Dissertations / Theses on the topic 'Noninvasive diagnostic'

It is known that the formation of oxidants, antioxidant protection, lipid peroxidation proteins are natural processes. However, these mechanisms imbalance initiates peroxidation of proteins, leading to cell dysfunction, in particular the ability of cells to generate and conduct impulses and energy of regulatory functions.

Le projet de recherche que j’ai suivi depuis 2015 concerne le diagnostic des troubles respiratoires du sommeil chez les enfants ayant une maladie génétique et leur prise en charge. Le projet a été développé entièrement dans l’unité de ventilation non invasive (VNI) et du sommeil de l’enfant de l’hôpital Necker Enfants malades de Paris.Dans le premier parti je me suis concentré sur le développement des nouveaux outils pour le diagnostic des troubles respiratoires du sommeil. La polysomnographie (PSG) représente l’examen de référence pour l’étude de troubles respiratoires du sommeil chez l’enfant. Néanmoins cet examen n’est pas disponible dans la plupart des centres hospitalier, est couteux et d’interprétation difficile. En plus, la qualité de l’examen est souvent réduite à cause de la perte involontaire ou à cause de l’intolérance de l’enfant aux capteurs posés. Pour cette raison, une de tache plus importante dans ce domaine c’est de développer des outils diagnostiques capables d’ameliorer la tolérance à l’examen et aussi sa performance. La première étude que j’ai suivie regarde la validation d’un particulaire capteur sous sternal pour la caractérisation des évènements respiratoires pendant une polygraphie ventilatoire. Les résultats de cette étude ont été publiés en 2016 (J Clin Sleep Med. 2016 Sep 13.). Une deuxième partie concerne la validation du même capteur pour la détection des évènements respiratoires chez l’enfant. Cette étude est actuellement en cours. Le but de ce projet est donc de démontrer la validité de ce capteur pour la détection et la caractérisation des évènements respiratoires chez l’enfant pour pouvoir permettre un ‘analyse complémentaire par rapport aux signaux dérivant des canules nasales et des bandes thoraco abdominales.La deuxième étude a analysé l’utilité de réductions de l’amplitude de l’onde de pouls pendant une polysomnographie, comme mesure des réveils corticaux liés aux évènements respiratoires. Le but de cette étude était de valider l’utilisation d’un outil simple pour remplacer l’analyse de l’EEG pour la détection des réveils corticaux associé aux évènements respiratoires. Les résultats de cette étude ont été publiés (Sleep Med. 2017 Jun;34:64-70).En ce qui concerne le deuxième parti je me suis concentré sur le traitement des troubles respiratoires du sommeil. La première étude a concerné l’efficacité du traitement par PPC dans une cohorte d’enfants ayant une séquence de Pierre Robin. Le but de cette etude etait de prouver l’efficacité de ce traitement pour eviter la tracheostomie dans ce groupe d’enfants ayant une obstruction severe des voies aeriennes superieures. Les résultats de cette étude ont été publiés en 2016 (Continuous Positive Airway Pressure for Upper Airway Obstruction in Infants with Pierre Robin Sequence (Reconstr Surg. 2016 Feb;137(2):609-12). La deuxième étude a permis d’analyser les critères de début de ventilation noninvasive (VNI) ou PPC dans une population d’enfant ayant des maladies génétiques hétérogènes. Les résultats de cette étude ont été publiés en 2016 (Sep;51(9):968-74). J’ai ensuite conclu une étude sur le début d’un traitement par PPC en ambulatoire. L’etude est actuellement en révision.J’ai aussi collaboré dans l’analyse des données et dans la rédaction des plusieurs études concernant les caractéristiques des troubles respiratoires du sommeil et de leur prise en charge chez des enfants porteurs de trisomie 21, de myasthénie congénitale et d’achondroplasie.J’ai ensuite recueilli les caractéristiques des troubles du sommeil dans une cohorte des patientes porteuses d’un syndrome de Rett
The research project I carried out since 2015 concerns the “diagnosis and treatment of SDB in children with genetic diseases”. The entire project was developed at the NIV and sleep unit of Necker Children Hospital in Paris.The first aim of my research project is focused on the development and improvement of new tools to diagnose SDB in children. PSG remains the gold standard for the diagnosis of SDB, but this exam is expensive, time consuming, difficult to interpret and most important, not available in most paediatric centres. Moreover, PSG quality is often affected by the involuntary displacement or loss of sensors or by the intolerance of the different sensors by the child. Given these considerations, one of the main challenges in paediatric sleep medicine is the development and validation of simplified tools, capable of improving the tolerance issues while assuring high and reliable accuracy.The first project I developed concerned the validation of a suprasternal pressure sensor to characterise sleep apnoea during respiratory polygraphy. This study was published in the Journal of Clinical Sleep Medicine in December 2016. A second part of this study is currently ongoing and explores the usefulness of the same sensor for the detection of respiratory events. The aim of this two part project is to demonstrate the validity of this sensor for the detection of airflow and respiratory efforts in children, thus allowing complementary analysis to nasal cannula and thoraco abdominal belts.The second project I carried out regards the use of the variations of pulse wave amplitude (PWA) as a surrogate of cortical microarousals. This study aimed at the validation of a surrogate of cortical microarousals in order to replace the standard EEG signal for their detection and to use PWA as a simple tool for the scoring of hypopneas during respiratory polygraphy. This study was published in Sleep Medicine in June 2017.During my PhD program, I also collaborate to another study concerning the use of pulse transit time (PTT) for the characterisation of respiratory events during polygraphy. This study was published in Sleep and Breathing in March 2017.The second axe of my research concerned the treatment of SDB in children with genetic and congenital disorders. The first study concerned the use of CPAP in the treatment algorithm of a series of infants with Pierre Robin sequence. This study highlighted the usefulness of CPAP in avoiding tracheostomy in this particular group of patients with severe OSAS. This paper was published in Plastic and Reconstructive Surgery in February 2016. The second study aimed at the identification of objective criteria that lead to the initiation of CPAP or NIV in children and infants. This study was published in Pediatric Pulmonology in September 2016. I also collaborated to the conception, data analysis and draft redaction of a second manuscript regarding the criteria authorising the weaning from CPAP and NIV in children. This paper was published in Pediatric Pulmonology in September 2017. A third article concerning a programme of outpatient initiation of CPAP in children is currently under revision in the Journal of Clinical and Sleep Medicine.I also collaborated in the conception, data analysis and manuscript revision of other papers regarding the description and management of SDB in children with Down syndrome, congenital myasthenia and achondroplasia.Finally, I am the first investigator of a study concerning sleep structure and sleep related respiratory events in girls with Rett syndrome

Implanted tissue engineered substitutes constitute dynamic systems, with remodeling mediated by both the implanted cells and the host. Thus, there exists a significant need for methods to monitor the function and morphology of tissue engineered constructs. Noninvasive monitoring using 1H Nuclear Magnetic Resonance (NMR) spectroscopy and imaging can prove to be the solution to this problem. Spectroscopy allows for assessment of cellular function through the monitoring of inherent metabolic markers, such as total-choline, while high resolution imaging enables the evaluation of construct morphology and interfacial remodeling. We applied these 1H NMR methods to monitor betaTC3 mouse insulinoma cells within hydrogel-based materials as a model pancreatic tissue substitute. In vitro research established a strong correlation between total-choline, measured by 1H NMR spectroscopy, and viable betaTC3 cell number, measured by MTT. Extending these methods to in vivo monitoring, however, was met with additional challenges. First, the implanted cells needed to be contained within a planar construct above a threshold density to allow for adequate quantification of the total-choline peak. Secondly, cell-free buffer zones between the implanted cells and the host tissue needed to be incorporated to prevent host tissue signal contamination. Finally, quantitative techniques needed to be developed to accurately account for contaminating signal from diffusing molecules. To overcome these challenges, a disk-shaped agarose construct, initially containing a minimum of 4 million betaTC3 cells and coated with an outer layer of pure agarose, was fabricated. Mathematical simulations aided the implant design by characterizing diffusive transport of nutrients and metabolites into and out of the construct. In vivo 1H NMR studies of these constructs implanted in mice established a strong correlation between total-choline, measured noninvasively using 1H NMR spectroscopy, and viable cell number, measured invasively using MTT. This study establishes total-choline as a reliable marker for noninvasively quantifying dynamic changes in viable betaTC3 cell number in vivo. 1H NMR imaging was used to monitor the implants structural integrity over time, while also assessing the hosts fibrotic response. We expect these studies to establish quantitative criteria for the capabilities and limitations of NMR methodologies for monitoring encapsulated insulinomas, as well as other tissue implants.

Les maladies chroniques du foie constituent un problème majeur de santé publique. L’évaluation précise du degré de fibrose hépatique apporte au clinicien une estimation du pronostic dès la prise en charge initiale de ces patients, mais permet également la réalisation d’une surveillance évolutive, et intervient dans la décision et le choix d’un traitement. L’évaluation noninvasive de la fibrose hépatique par élastographie a permis de révolutionner la prise en charge des malades atteints d’une maladie chronique du foie. L’objectif de notre travail est d’évaluer les performances diagnostiques d’une nouvelle technique d’élastographie hépatique, appelée « Supersonic ShearImaging » (SSI), et d’analyser sa plus-value dans l’évaluation non-invasive des maladies chroniques du foie.Dans une première étude, nous avons prospectivement analysé et comparé les performances diagnostiques de l’élastographie SSI par rapport au FibroScan et l’ARFI pour le staging de la fibrose hépatique sur une série de 349 patients avec une maladie chronique du foie diagnostiquée et gradée par ponction-biopsiehépatique.Dans une seconde étude, nous avons prospectivement étudié l’impact diagnostique de l’élastographie SSIsur le foie et la rate chez une population de 401 patients avec cirrhose pour l’évaluation de la gravité de la maladie cirrhotique.Dans une troisième étude, nous avons réalisé une analyse prospective bicentrique (Angers et Bordeaux)de la performance diagnostique de l’élastographie SSI par rapport au FibroScan et l’ARFI dans l’évaluation non invasive de la fibrose hépatique sur une série de 291 patients avec stéatopathie non-alcoolique et ponction-biopsiehépatique
Abstract :The management and the prognosis for chronic liver diseases are widely based on the presence and the development of a liver fibrosis. The progressive worsening of liver fibrosis leads in a certain number of patients to the development of cirrhosis and its complications. Thus, the development of non-invasive diagnostic tools for the diagnosis and the monitoring of the liver fibrosis is of crucial interest. Liver elastography is one of the most promising techniques that have recently emerged in the field of chronic liver diseases. In this study, we aim to assess the diagnostic accuracy of a new elastography technique, named “Supersonic Shear Imaging” (SSI), and toanalyse its added value in the non invasive diagnosis of chronic liver diseases.In a first study, we prospectively analysed and compared the diagnostic performances of SSI elastography versus FibroScan and ARFI for the staging of liver fibrosis in a cohort of 349 patients with chronic liver diseases that consecutively underwent a liver biopsy. In a second study, we prospectively analysed the impact of liver and spleen SSI elastography in a cohortof 401 cirrhotic patients for the non invasive diagnosis of cirrhosis severity and oesophageal varices.In a third study, we assessed the clinical use of liver stiffness measurement evaluated by SSI, FibroScan,and ARFI in a cohort of nonalcoholic fatty liver disease patients who underwent liver biopsy. A total of 291 NAFLD patients were prospectively enrolled at 2 French university hospitals (Angers and Bordeaux)

To works of art is often assigned a specific value of cultural and expressive testimony of an artist or, more generally, of a culture. Preserve this value means keeping intact the appearance of the work and its component material in order for the message to reach the public, without alteration. A good knowledge of the materials constituting the work is needed to preserve them appropriately. My research work is focused on the study of modern and contemporary paintings and of materials used, which are not well known compared to traditional materials. The main goal of this work was to investigate some of the most popular art materials to track even the weakest changes, which are index of degradation and occur in the form of chromatic alterations. Image spectroscopy (IS) was the scientific technique on which we focused the attention, since it helps to reveal early alterations using imaging, in a complete non-invasive way. Spectral data in the VIS-NIR range were processed by multivariate statistical analysis. The use of Principal Component Analysis (PCA) on IS spectra was applied to modern painting materials, as Titanium White, Artificial Ultramarine Blue in acrylic and oil binders in a test panel. IS + PCA has proven to be an effective method for the early identification of chromatic alterations, although of faint amounts. Moreover, colorimetric data have provided useful and complementary information, recognizing the alterations trends. Unexpectedly, IS has also demonstrated a discriminant power for some materials. The most striking case was the identification of white Lithopone for an absorption band in the visible range, due to the presence of cobalt as vicariant element of Zinc. The knowledge of changes in the chemical composition of this pigment in a specific time period has allowed the recognition of a fake in contemporary artwork. Other scientific methodologies have been used. X-ray fluorescence was used to collect more detailed information about the materials. This can be the case of examinations on Jean Metzinger’s work, present in the Peggy Guggenheim Collection (Venice). Image diagnostics, as Ultraviolet fluorescence, Wide band infrared reflectography, have proved useful to collect information on the state of conservation of works in non-quantitative way. The common features of such techniques are to be non-invasive, non-destructive, to be used in situ.

Les moteurs électriques sont responsables de 67% de la consommation d’électricité dans l’industrie. Remplacer les moteurs installés par des entrainements plus efficients requiert de statuer sur leur adéquation avec les charges qu’ils entrainent. Une contrainte forte est de les analyser « on-line » et sans mesures intrusives ni consignations des installations.Cette thèse répond à un triple objectif. Premièrement, un dispositif de diagnostic « non-invasif » facilement intégrable en milieu industriel a été développé avec quatre méthodes d’évaluation du niveau de charge des moteurs asynchrones directement connectés au réseau. Deux de ces méthodes, existantes et basées sur la mesure du courant et du flux magnétique de dispersion, font l’objet d’améliorations significatives qui les portent à un niveau TRL7. Les deux autres méthodes exploitent la mesure seule du flux de dispersion. Leur applicabilité est vérifiée pour une alimentation par un système de tensions, équilibré ou non, avec des variations permanentes ou aléatoires. Une étude plus exploratoire montre que l’estimation non-invasive du courant absorbé par les machines asynchrones alimentées par convertisseurs électroniques est possible par exploitation du flux rayonné. Deuxièmement, le dispositif de diagnostic énergétique et des algorithmes de recherche de motorisation adaptée à un cycle de fonctionnement défini ont été appliqués à des exemples concrets d’optimisation énergétique sur un site industriel très énergivore, une aluminerie. Troisièmement, cette étude propose une réflexion sur la gestion d’un parc moteurs et, notamment, sur l'analyse des performances des moteurs neufs comparés à ceux ayant subi un rebobinage
In the industry, electrical motors are responsible for 67% of electricity consumption. Replacing installed motors by more efficient ones requires the knowledge of their suitability with the loads that they drive. Analyzing the load variations without intrusive measurements or installations consignments is a strong constraint.That is why this thesis has a threefold purpose. Firstly, a “noninvasive” diagnostic device has been developed with four methods for evaluating the load of grid-connected induction motors. Two of these methods, based on the measurement of the current and the magnetic stray flux, have been significantly improved up to TRL7. The two other methods exploit only the measurement of the stray flux. Their applicability is checked for balanced and unbalanced supply voltage systems with permanent or random variations. A more exploratory study shows that the noninvasive estimation of the current for inverter-fed induction machines is possible using the radiated external flux. Secondly, the energy diagnosis device and search algorithms adapted to an operating cycle motorization have been applied to practical examples of energy optimization in an electro-intensive industrial plant, an aluminum smelter. Thirdly, a reflection on the management of a motor fleet is proposed, in particular, on the performance analysis between new motors and rewounded ones

Thesis: Ph. D. in Biomedical Engineering, Harvard-MIT Program in Health Sciences and Technology, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 149-166).
Accurate, timely, and effective diagnosis is the first step in appropriately treating disease. Many diseases have confusing symptoms, nonspecific biomarkers, or require invasive biopsy; these factors and others contribute to the low rates of early diagnosis for noncommunicable diseases like cancer, clotting disorders, or fibrotic diseases. A promising approach is the introduction of pro-diagnostic agents that interact with pathologic processes to produce a readout. In this vein, our group has developed responsive nanomaterials that, upon cleavage by disease-associated proteases, release reporters into the urine. This thesis sought to improve these tools by enabling the noninvasive quantification of disease-associated protease activity, deskilling complex diagnostic procedures, and developing a pipeline for extending these tools to additional diseases. Drawing inspiration from existing diagnostics, we modified our protease nanosensors to release ligand-encoded reporters compatible with clinical ELISA and paper-based lateral flow assays. These detection techniques enable simple and inexpensive quantification of our synthetic disease reporters by ensuring compatibility with existing diagnostic resources and infrastructure. To demonstrate our platform's versatility, we adapted it to a highly sensitive single molecule array (SiMoA) assay and validated disease detection in mice using 1000-fold lower doses of nanosensors. We next used disease-specific protease expression data to develop an inhalable formulation of our protease nanosensors and investigated direct tissue delivery. Finally, we built a pipeline to improve protease substrate sensitivity and specificity. Using liver fibrosis as a model, we identified target proteases, designed a peptide-screening assay, and nominated peptide candidates that efficiently classify diseased tissue. The protease nanosensors developed here provide a noninvasive, quantitative, and otherwise unavailable glimpse of the complex proteolytic milieu of disease and health. These tools form a framework for developing new diagnostics that simply, rapidly, and inexpensively identify protease-driven diseases without complex equipment or specialized personnel.
by Andrew David Warren.
Ph. D. in Biomedical Engineering

Résumé de l'étude in vitro. L'objectif de cette étude in vitro était de créer un fantôme avec la même architecture musculaire (fibre, aponévrose ...) et les mêmes propriétés mécaniques que le muscle en condition passive et active. Deux fantômes homogènes ont été fabriqués avec différentes concentrations de plastisol pour simuler les propriétés élastiques du muscle en condition passive (50% plastisol) et active (70% de plastisol). Pour cela, des fils en Téflon (d = 0,9 mm) ont été insérés dans la partie supérieure du fantôme (50%) pour représenter les fibres musculaires. De plus, une feuille en matière plastique (8 x 15 cm) a également été placée au milieu du fantôme pour imiter la structure de l'aponévrose. Ensuite, des tests ERM ont été effectués à 90 Hz avec deux stimulateurs pneumatiques de différentes formes (tube en silicone, membrane circulaire) pour analyser l'effet du type du stimulateur sur la propagation des ondes. La longueur d'onde a été mesurée à partir des images phase et les propriétés élastiques (module de cisaillement) ont été calculées. Les deux fantômes (50% et 70%) ont montré des propriétés élastiques similaires à celles du muscle à l’état passif (2,40 ± 0,18 kPa) et actif (6,24 ± 0,21 kPa). Le stimulateur en forme de tube a donné des valeurs plus élevées (environ 1,2 kPa à 1,53 kPa). L'analyse du comportement des ondes a révélé un glissement le long de la feuille plastique. Ce phénomène a aussi été observé in vivo le long de l’aponévrose. L'onde a également été sensible à la présence des fils en téflon car des coupures, des trous, ont été identifiés au cours de la propagation de l’onde. Une nouvelle méthode de post-traitement a été créée pour mesurer les paramètres G' et G" à partir de tests ERM réalisés à plusieurs fréquences (60, 80, 100 Hz) et en utilisant des modèles rhéologiques. Cette méthode a été testée sur un fantôme (50%) qui n’avait pas d’inclusion. Les résultats des mesures viscoélastiques (G', G") ont été validés avec la technique HFVS (Hyper-Fréquence viscoélastique Spectroscopy). Des valeurs similaires, G' et G’’, ont été obtenues avec les deux techniques. Ce dernier résultat valide la nouvelle méthode de post-traitement pour mesurer les propriétés viscoélastiques. Résumé de l'étude in vivo. L'objectif de cette étude in vivo a été de développer des protocoles ERM pour caractériser les propriétés élastiques (module de cisaillement) des neuf muscles de la cuisse. Ces tests ont été effectués à une seule fréquence (90 Hz). Différents modules de cisaillement ont été trouvés entre les muscles. Le gracilis a révélé des propriétés élastiques plus élevées que les autres muscles. Ces différentes élasticités peuvent être dues à différentes compositions physiologiques et architecturales entre les tissus. Ensuite, les propriétés viscoélastiques des muscles ischio (ST, SM, et la BC) et du muscle Gr ont été déterminées en appliquant la nouvelle méthode de post-traitement des données (précédemment validée sur le fantôme 50%) avec des tests ERM multi fréquences (70, 90 et 120 Hz) et en utilisant des modèles rhéologiques. Les résultats ont montré que deux modèles rhéologiques, Zener et springpot, peuvent être utilisés pour mesurer les propriétés viscoélastiques des muscles à l’état passif. De plus, des résultats similaires ont été trouvés entre G "/ G ', obtenus expérimentalement à 90 Hz, et la valeur α du modèle de springpot
Summary of the vitro studies. The objective of this in vitro study was to create a phantom witch the same muscle architecture (fiber, aponeurosis …) and mechanical properties of muscle in passive and active states. Two homogeneous phantoms were manufactured with different concentrations of plastisol to simulate the muscle elastic properties in passive (50% of plastisol) and active (70% of plastisol) muscle conditions. Moreover, teflon tubing pipes (D = 0.9 mm) were thread in the upper part of the phantom (50%) to represent the muscle fibers and a plastic sheet (8 x 15 cm) was also included in the middle of the phantom to mimic the aponeurosis structure. Subsequently, MRE tests were performed at 90Hz with two different pneumatic drivers, tube and round shapes, to analyze the effect of the type of driver on the wave propagation. The wavelength was measured from the phase images and the elastic properties (shear modulus) were calculated. Both phantoms revealed elastic properties which were in the same range as in vivo muscle in passive (2.40 ± 0.18 kPa) and active (6.24 ± 0.21 kPa) states. The impact of the type of driver showed higher values with the tube (range: 1.2 kPa to 1.53 kPa). The analysis of the wave behavior revealed a sliding along the plastic sheet as it was observed for in vivo muscle study. The wave was also sensitive to the presence of the fibers where gaps were identified. A new post processing method was established to measure G’ and G” from experimental multi frequencies (60, 80, 100 Hz) MRE (MMRE) tests and rheological models. This method was tested on the phantom (50%) made without fiber. Cross validation of the viscoelastic (G’, G”) results was made with Hyper-Frequency Viscoelastic Spectroscopy (HFVS). Both techniques showed similar range of values for G’ and G” at the same frequencies. This last result validated our new data processing for the viscoelastic measurement. Summary of the in vivo studies. The objective of this in vivo study was to develop MRE protocols to characterize the elastic properties (shear modulus) of the nine thigh muscles. These tests were performed at a single frequency (90Hz). Different shear moduli were found between the muscles. The gracilis revealed the highest elastic properties compared to all the other muscles. These different elasticities may be due to different physiological and architectural compositions between the tissues. Then the viscoelastic properties of the ischio (ST, SM, and BC) and Gr muscles were determined based on our new data-processing method (validated on the phantom 50%) using MMRE tests (70, 90 and 120Hz) and rheological models. The results revealed that two rheological models, zener and springpot, can be used to measure the viscoelastic properties in passive state. A similar trend was found between the experimental ratios G”/G’ obtained at 90 Hz and the α value of the springpot model. The present MRE muscle protocol, and the viscoelastic data base, could be used as non-invasive diagnostic tools to evaluate tissue alterations, the progression of diseases, and the effect of treatments, such as the ongoing therapeutic trials for Duchenne muscular dystrophy

In order to identify patients with severe coronary artery disease (CAD) and at a higher risk of future cardiac events after uncomplicated myocardial infarction, 105 consecutive patients were studied prospectively. There were 93 men and 12 women with a mean age of 56 +/- 8.2 years. Treadmill testing, exercise radionuclide ventriculography, thallium-201 myocardial imaging and selective coronary arteriography were performed 6-8 weeks after infarction. Patients were grouped into those who had single and multiple vessel disease. Multiple regression analysis of 18 noninvasive indices was carried out using generalized linear interactive modelling (GLIM) and the results were compared with the severity of underlying CAD and the clinical outcome after a mean follow-up period of 18.8 +/- 3. 4 months. At the end of the follow-up period, patients were categorized into those who had no cardiac events, minor and major cardiac events. Multivariate analysis produced an algorithm from three factors found to be most predictive of the severity of CAD. These included ST-segment depression on exercise, total score of rest and exercise regional wall motion and the presence of significant redistribution on thallium-201 imaging. The sensitivity of this algorithm for predicting multiple vessel disease was 42%, with a specificity of 94%, and a predictive accuracy of 69%. However, the total score of regional wall motion abnormalities was the single most predictive factor of major cardiac events with a sensitivity of 94%, a specificity of 57%, and predictive accuracy of 63%. None of the other factors produced additional prognostic information. Therefore, exercise radionuclide ventriculography appears to be the investigation of choice in assessing prognosis after myocardial infarction.

Coherence is the fundamental property of optical radiation. Methods based on this characteristic are employed in different areas of research even in NASA and European space agency. However, coherence properties of light can be successfully applied in life sciences for the purposes of diagnostics and treatment. The subject of current research is the development and improvement of the quantitative performance of non-invasive low coherence optical diagnostic which is a novel modern biomedical technique uniquely suited for the measurements of particles distribution within the topical layers of biological tissues and other complex media, such as polymers, colloids, composite materials, etc. This approach is based on the illumination of a medium by optical radiation with a low coherence both spatial and temporal, and analysis of the back-scattering signal. Recently introduced this technique is not currently used. The main difficulty in the developing of practical low-coherence systems in biomedical diagnostics is associated with the complexity of biotissues structure. For example, the human skin has very complex structure and consists with several layers of cells with unique optical properties in each layer. External boundary and internal boundaries between layers are rough and wavy. Thus, the most accurate description of optical radiation propagation is extremely complicated to achieve and can be performed only as a computer simulation. All further investigations of the optical methods of biotissues diagnostics can be enhanced using such computer models.

Dissertation (Ph.D.)--University of Toledo, 2005.
Typescript. "A dissertation [submitted] as partial fulfillment of the requirements of the Doctor of Philosophy degree in Engineering." Bibliography: leaves 106-120.

Le FibroTest (Brevet APHP-Sorbonne Université) est un marqueur quantitatif de la sévérité de la fibrose, largement validé chez les sujets avec les quatre maladies chroniques les plus fréquentes: les hépatites chroniques C et B, la maladie alcoolique du foie et la stéatose non alcoolique du foie (NAFLD). Sa valeur pronostique pour la prédiction des décès liés au foie a également été validée dans ces maladies à l'exception de la NAFLD, probablement en raison de la progression plus lente de la fibrose, et du fait de la plus grande fréquence des décès d'origine extra-hépatique et la plus faible incidence des décès d'origine hépatique par rapport aux autres causes virales ou alcooliques. L'objectif principal de la thèse a été de démontrer que la valeur pronostique à long terme (10 ans) du FibroTest pour la mortalité liée au foie était équivalente à celle obtenue pour les patients avec hépatite chronique C, la population la mieux validée. Grâce à la précocité d'utilisation du Fibrotest utilisé dès 1997 dans la cohorte prospective de la Pitié-Salpêtrière (projet FibroFrance) il a été possible sur 20 ans de suivre suffisamment de patients à risque métabolique pour valider les performances pronostiques du FibroTest qui étaient au moins égales à celles obtenues chez les patients avec hépatites chroniques virales C et B et les maladies alcooliques du foie. La moitié de la mortalité des maladies du foie étant due au cancer du foie, le deuxième objectif a été de construire et de valider en interne deux nouveaux marqueurs précoces prédictifs de ce cancer, HR1 et HR2 (brevets APHP-Sorbonne Université), chez les sujets avec maladies chroniques du foie, sans ou avec cirrhose initiale. Ces tests combinent l'apolipoprotéine-A1, l'haptoglobine, deux protéines "hépato-protectrices", avec la gammaglutamyl transférase, un marqueur simple et sensible de cytotoxicité. HR1 ne comprend pas de marqueur spécifique de cancer et HR2 utilise l'alpha-foetoprotéine. Nos travaux ont démontré que l'apolipoprotéine-A1 et l'haptoglobine ont une valeur pronostique chez les sujets sans cirrhose avec hépatite médicamenteuse (DILI-ActiTest, brevet APHP-Sorbonne Université), et chez les sujets avec maladies chroniques du foie avec et surtout sans cirrhose, pour prédire précocement le risque de cancer du foie, qualités inconnues au début du projet FibroFrance. L'algorithme de surveillance combinant HR1 et HR2 permet chez les sujets de plus de 50 ans avec ou sans cirrhose de détecter un cancer pour 10 sujets dépistés, et donc autoriserait un dépistage coût-efficace. Pour le troisième objectif, l'amélioration des marqueurs de stéatose et de NASH, deux nouveaux tests quantitatifs ont été construits et validés, (brevets APHP-Sorbonne Université): le NashTest-2 pour le diagnostic de NASH et le SteatoTest-2 pour le diagnostic de stéatose. Pour prendre en charge ces patients à risque métabolique, les tests ont été construits pour reproduire le mieux possible le compte-rendu de biopsie du foie, c’est à dire estimant la présence et la gravité des trois lésions histologiques élémentaires : la stéatose, l'activité inflammatoire et la fibrose. C'est pour cette raison qu'un long travail méthodologique préalable a été mené pour utiliser au mieux les scores de référence maintenant uniformisé par les anatomopathologistes européens et américains. Les principales limites de ces travaux sont l'absence de larges validations externes chez les sujets à risque métabolique, pour reproduire les résultats observés sur nos cohortes, et ce d'autant plus qu'il existe un conflit d'intérêt. Pour les tests largement utilisés pour les hépatites virales et les maladies alcooliques du foie, et la première génération de tests pour les maladies métaboliques, les validations indépendantes avaient confirmé les performances initiales
The FibroTest (Patent APHP-Sorbonne University) has been validated as a biomarker for the diagnosis of the stages of fibrosis in non-alcoholic-fatty liver disease (NAFLD) with results similar to those in chronic hepatitis C, B and alcoholic liver disease (ALD), but it has not yet been confirmed for the prediction of liver-related death. This was mainly due to the lower incidence of liver related deaths, and the higher incidence of non-liver related deaths, as well as the slower progression of fibrosis to cirrhosis, in NAFLD in comparison with other liver diseases. The primary aim was to assess the long-term (10-year) prognostic value of FibroTest in NAFLD and in comparison with that observed in CHC, the most validated population. Due to the very early start of the FibroFrance project in 1997, FibroTest was prospectively assessed in the Pitié-Salpêtrière cohort allowing a 20 years follow-up with a sufficient number of liver-related deaths. As half of the liver-related deaths were due to primary liver cancer, the second aim was to construct and validate internally two new multi-analyte tests, HR1 and HR2 (APHP-Sorbonne University Patents) for the early prediction of cancer, in patients with chronic liver diseases, without and with cirrhosis. Those tests combined apolipoprotein- A1 and haptoglobin, two "hepato-protective" proteins, with gammaglutamyl transferase, a simple marker of cytotoxicity, without specific marker of liver cancer for HR1, and with alpha-fetoprotein for HR2. Our work demonstrated that apoliporotein-A1 and haptoglobin had a prognostic value in patients without cirrhosis and drug-induced liver injury (DILI-ActiTest, APHP-Sorbonne University patent), and in patients with chronic liver diseases with and mostly without cirrhosis, permitting to identify very early the patients at high risk of cancer. These advantages of these proteins were unknown when our project started in 1997. A surveillance algorithm combining HR1 and HR2 in patients older than 50-year permitted to detect one cancer every 10 patients screened. For the third aim, the improvement of blood test for the diagnosis of steatosis and NASH, two new quantitative tests have been constructed and internally validated (APHPSorbonne University Patents), SteatoTest-2 and Nash-Test-2. To manage patients with metabolic risk, these tests have been constructed to reproduce as well as possible the pathologist report of the biopsy, that is estimating the presence and the severity of the elementary histological features: steatosis, inflammatory activity and fibrosis. For this reason a long methodological analysis has been performed to better use as reference the scoring systems now uniformized and recommended by European and American pathologists. The main limitations of our works were the absence of large external validations in patients with metabolic risk, in order to reproduce our results, especially according to a conflict of interest. For the other blood tests widely used in chronic viral hepatitis and alcoholic liver disease, as well as the first generation used in NAFLD, the independent external validations has confirmed the initial performances

A non-invasive, in vitro method of estimating mean pulmonary artery pressure (PAP) was developed. This information was obtained by establishing a relationship between the pneumatic right drive pressure (RDP) and PAP waveforms. The RDP-PAP relationship was formalized into a series of multiple-linear regression equations for TAH cardiac cycles of known fill volume (FV). Correlation of computed estimates of PAP to actual measurements showed that these equations were greater than 92% accurate within 1.84 mmHg. In addition, while the RDP-PAP relationships were wholly dependent on FV, it was shown that they are independent of the manner in which FV was obtained. This method proved useful over the clinical operating range of the pneumatic heart driver, as well as over the normal physiological range of PAP in the human. Effectiveness of this method in vivo needs to be demonstrated.

Elevated pulmonary artery pressure (PAP) is a significant healthcare risk. Continuous monitoring for patients with elevated PAP is crucial for effective treatment, yet the most accurate method is invasive and expensive, and cannot be performed repeatedly. Noninvasive methods exist but are inaccurate, expensive, and cannot be used for continuous monitoring. We present a machine learning model based on heart sounds that estimates pulmonary artery pressure with enough accuracy to exclude an invasive diagnostic operation, allowing for consistent monitoring of heart condition in suspect patients without the cost and risk of invasive monitoring. We conduct a greedy search through 38 possible features using a 109-patient cross-validation to find the most predictive features. Our best general model has a standard estimate of error (SEE) of 8.28 mmHg, which outperforms the previous best performance in the literature on a general set of unseen patient data.

Thesis (M.S.)--University of Akron, Dept. of Biomedical Engineering, 2006.
"May, 2006." Title from electronic thesis title page (viewed 01/16/2008) Advisor, Dale Mugler; Co-Advisor, Bruce Taylor; Committee member, Daniel Sheffer; Department Chair, Daniel Sheffer; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1985.
MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.
Vita.
Includes bibliographical references.
by Jonathan Marc Teich.
Ph.D.

Die im Rahmen dieser Arbeit vorgestellten Studien führen zu einer Erweiterung der Indikationen der kardiovaskulären Magnetresonanztomographie bei der Diagnostik der koronaren Herzerkrankung. Die Methoden zur schnellen Erfassung der Myokardbewegung bis hin zu Echtzeittechniken, zur Bestimmung der Myokardperfusion, zur Quantifizierung von hibernating Myokard und zur Unterdrückung von Atemartefakten bei der Koronararteriendarstellung oder Koronarflussmessung wurden optimiert und in klinischen Studien evaluiert. Die Magnetresonanztomographie ist der Echokardiographie bei Dobutamin-Stress-Untersuchungen zur Erkennung einer koronaren Herzerkrankung signifikant überlegen, was sich insbesondere durch die bessere Bildqualität erklärt. Dabei kann zur Überwachung der Patienten während der Stressuntersuchung auf Echtzeitverfahren zurückgegriffen werden, die sowohl für eine quantitative Analyse der linksventrikulären Funktion, als auch für die Erkennung von stressinduzierten Wandbewegungsstörungen geeignet ist. Für die Beurteilung der Myokardperfusion ist die Magnetresonanztomographie mit herkömmlichen Techniken wie SPECT oder PET vergleichbar. Dabei ist insbesondere die Analyse der Einwaschgeschwindigkeit eines Kontrastmittelbolus in Ruhe und unter Vasodilatation geeignet, ischämische und normal perfundierte Myokardabschnitten zu differenzieren. Für die Abbildung der Koronararterien haben sich insbesondere Navigatortechniken als sinnvoll erwiesen. Dabei kann die Anwendung optimierter Korrekturverfahren der Zwerchfellposition zu einer Verringerung von ateminduzierten Bewegungsartefakten führen. Mit Hilfe diese Navigatortechnik können auch Koronarflussmessungen optimiert und ihre Genauigkeit im Vergleich zur intravaskulären Doppler-Sonographie durch Verbesserung der räumlichen und zeitlichen Auflösung gesteigert werden. Damit steht die kardiovaskuläre Magnetresonanztomographie an der Schwelle zum breiten Einsatz in der klinischen Routine. Das derzeitige Indikationsspektrum ist für eine integrative und genaue Untersuchung geeignet und kann in den nächsten Jahren durch weitere Aspekte (z.B. Darstellung von Gefäßplaques, Anwendung spezifischer Kontrastmittel) noch erweitert werden.
The studies compiled in the following manuscript lead to a broadening of indications for cardiovascular magnetic resonance imaging for the diagnosis of coronary artery disease Methods for rapid assessment of myocardial motion including real-time techniques, for the determination of myocardial perfusion, for the quantification of hibernating myocardium, and for the reduction of artefacts from breathing motion for the visualization of the coronary arteries and coronary flow measurements were optimised and evaluated in clinical studies. Dobutamin stress magnetic resonance imaging is superior to dobutamine stress echocardiography for the detection of coronary artery disease, which is mainly due to the superior image quality. For patient monitoring real-time techniques can be used which allow quantitative assessment of left ventricular function and detection of stressinduced wall motion abnormalities. The accuracy of perfusion measurements with magnetic resonance imaging is comparable to conventional techniques such as SPECT of PET. Especially the analysis of the wash-in of a contrast agent bolus at rest and during vasodilation allows a differentiation of ischemic and normal myocardium. For coronary artery imaging especially navigator techniques have been shown to be useful. The application of optimised correction techniques for the position of the diaphragm can lead to a reduction of breathing induced artefacts. Thus, cardiovascular magnetic resonance is on its way towards broad clinical application. The current spectrum of indications allows an integrative and accurate examination and can be expanded with additional aspects (e.g. plaque imaging, use of specific contrast agents) in the next years

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado.
This paper proposes a technological solution using a predictive analysis model to identify and reduce the level of risk for type 2 diabetes mellitus (T2DM) through a wearable device. Our proposal is based on previous models that use the auto-classification algorithm together with the addition of new risk factors, which provide a greater contribution to the results of the presumptive diagnosis of the user who wants to check his level of risk. The purpose is the primary prevention of type 2 diabetes mellitus by a non-invasive method composed of the phases: (1) Capture and storage of risk factors; (2) Predictive analysis model; (3) Presumptive results and recommendations; and (4) Preventive treatment. The main contribution is in the development of the proposed application.
Revisión por pares

Introduction: Au Québec, environ 110 000 femmes enceintes sont éligibles au dépistage prénatal volontaire de la trisomie 21(T21). Différentes stratégies de dépistage sélectionnent environ 4% des femmes à haut risque pour le test invasif (amniocentèse) en vue d'un diagnostic définitif. Les nouveaux tests génomiques prénataux non invasifs (TGPNI) utilisant l'ADN fœtal circulant dans le sang maternel pourraient réduire ces procédures invasives. Leur introduction dans les programmes nationaux de dépistage requiert cependant que des données sur leur coût-efficacité et leur impact budgétaire soient produites. Objectifs : L’objectif principal de cette thèse était d'évaluer les aspects économiques attendus de l'introduction du TGNI dans le programme québécois de dépistage de la trisomie 21. La première étude a consisté en une revue systématique de la littérature des évaluations économiques sur les TGPNI. La deuxième étude a porté sur l'évaluation économique de 7 stratégies de dépistages incluant le TGPNI comparées ainsi que des 6 stratégies de dépistage traditionnelles recommandées par la Société canadienne d’obstétrique et de gynécologie(SOGC). La troisième étude a porté sur l'évaluation de l'impact budgétaire attendu de l’implantation du dépistage par TGPNI dans le programme québécois de dépistage de la trisomie 21. Méthodologie: Une revue systématique de la littérature a été réalisée pour la première étude. Pour la deuxième étude, ainsi que la troisième, des modèles de décision semi-markoviens ont été élaborés pour simuler l’évaluation économique et l'impact budgétaire du dépistage par TGPNI pour une cohorte virtuelle de femmes enceintes similaire à celle des femmes enceintes du Québec en termes d'âge et de nombre de grossesses par âge. La perspective du système de santé québécois a été considérée. Pour l’évaluation économique, 13 stratégies de dépistage ont été comparées : 6 traditionnelles recommandées par la Société canadienne d’obstétrique et de gynécologie, 6 incluant le TGPNI comme test de dépistage de deuxième intention et 1 considérant le TGPNI en première intention. Quant à l’analyse d’impact budgétaire, elle a porté sur l’option considérée comme la plus coût-efficace par la deuxième étude, c’est-à-dire le TGPNI en deuxième intention offert aux femmes à haut risque (Sérum intégré +TGPNI). Cette option a été comparée à la stratégie actuellement offerte par le programme de dépistage au Québec (Sérum intégré). La principale issue pour l'analyse coût-efficacité était le coût additionnel par trisomie 21 additionnelle détectée. Celle de l'analyse d'impact budgétaire était la différence de coûts entre la stratégie incluant le TGPNI et la stratégie de dépistage actuelle. Résultats: La première étude qui a inclus 16 études a révélé que par rapport aux stratégies de dépistage actuelles, la stratégie offrant le TGPNI à toutes les femmes n'était pas coût-efficace. C'est l'option du TGPNI offert aux femmes enceintes à risque élevé qui s'avère l'option la plus coût-efficace dans la majorité des études incluses. La deuxième étude a montré que, sur un total de 13 stratégies comparées, la stratégie « Dépistage par sérum intégré suivie par le TGPNI » est celle qui coûte le moins cher et la stratégie « TGPNI universel » est celle qui coûte le plus bien qu'étant la plus efficace. Ainsi, la stratégie « Dépistage par sérum intégré suivie par le TGPNI » est considérée comme plus la coût-efficace. D'autres stratégies, bien que relativement plus efficace pour détecter le nombre de cas T21, entraînent une augmentation des coûts marginaux par cas additionnel détecté allant de 61 623 $ à 1 553 615 $. Les résultats étaient sensibles au coût du TGPNI et aux seuils considérés pour déterminer les femmes enceintes à risque élevé. La troisième étude a montré que le TGPNI offert aux femmes à haut risque identifiées par le programme de dépistage actuel serait abordable pour le système de santé québécois. Comparativement au programme de dépistage actuel, son implantation se ferait à coût neutre considérant une modeste économie annuelle de 80 432 $ (IC à 95%: 79 874 $ - 81 462 $). Les résultats étaient sensibles aux coûts du TGPNI et au taux d'acceptation des tests diagnostiques invasifs. Conclusion: Le TGPNI comme test de seconde intension, c'est-à-dire offert aux femmes à haut risque selon les critères du programme de dépistage actuel, est coût-efficace et abordable pour le système de santé québécois. Avant d'envisager son introduction, les décideurs devraient cependant considérer d'autres aspects, notamment les aspects éthiques.
Introduction: In the Province of Quebec, about 110,000 pregnant women are eligible to voluntary prenatal screening for trisomy 21(T21). Conventional screening strategies select about 4% of women for invasive fetal chromosome testing. Noninvasive prenatal testing using maternal blood cell-free DNA (NIPT) is a new highly accurate screening strategy that could reduce these invasive procedures but evidence about its health economic aspects (cost-effectiveness and affordability) is still lacking. Objectives: The objective of this thesis is to evaluate the expected health economic aspects of introducing NIPT into the Quebec trisomy 21 screening program. The first study systematically reviewed the literature of full economic evaluation studies on NIPT. The second study evaluated the expected cost-effectiveness of screening strategies incorporating NIPT, as well as conventional screening strategies. The third study evaluated the expected budget impact of implementing NIPT into the Quebec trisomy 21 screening program. Methodology: A systematic review of literature was performed for the first study. For the second and third studies, semi-Markov decision-analytic models were built to simulate the cost-effectiveness and the budget impact of NIPT for a virtual cohort of pregnant women similar to that of Quebec in terms of age and pregnancy rate by age. The main outcome for the cost-effectiveness analysis was the incremental cost per additional trisomy 21 detected. The main outcome for the budget impact analysis was the difference in the overall costs between the two alternatives: the current screening strategy vs. the most cost-effective strategy incorporating NIPT). Results: The first study included 16 studies. Results show that compared to current screening practice a universal NIPT screening program is not cost-effective. A program that offers NIPT to high risk pregnant women was found to be the most cost-effective option in the majority of studies included. The second study showed that NIPT as a second-tier test for high-risk women is cost-effective compared to screening algorithms not including NIPT. Out of 13 strategies compared, the integrated serum screening strategy followed by NIPT was the most cost-effective strategy. Other strategies can improve the number of T21 cases identified, but with increasing incremental costs per case (from $ 61,623 to $1,553,615). Results were sensitive to NIPT cost and cut-offs considered to determine high risk pregnant women. The third study found that NIPT as a second-tier test offered to high-risk women identified by the current screening program is affordable for the Quebec health care system. Compared to the current screening program, this strategy could be implemented at a neutral cost considering a modest yearly saving of $80,432 (95% CI: $79,874-$81,462). Results were sensitive to the NIPT costs and the uptake-rate of invasive diagnostic tests. Conclusion: NIPT as a second-tier test offered to high-risk women identified by the current screening program is cost-effective and affordable for the Quebec health care system. Decision makers should consider its introduction after considerations of others aspects such as ethical issues.

[EN] Atrial tachyarrhythmias present a high prevalence in the developed world, and several studies predict that in the coming decades it will be increased. Micro or macro-reentrant mechanisms of the electrical wavefronts that govern the mechanical behavior of the heart are one of the main responsibles for the maintenance of these arrhythmias. Atrial flutter is maintained by a macro-reentry around an anatomical or functional obstacle located in the atria. In the case of atrial fibrillation, the hypothesis which describes high frequency rotors as dominant sources of the fibrillation and responsible for the maintenance of the arrhythmia, has been gaining relevance in the last years. However, the therapies that target high frequency sources have a limited efficacy with current techniques. Radiofrequency ablation allows the destruction of parts of the cardiac tissue resulting in the interruption of the reentrant circuit in case of macro-reentries or the isolation of micro-reentrant circuits. The non-invasive location of reentrant circuits would increment the efficacy of these therapies and would shorten surgery interventions. In parallel, pharmacological therapies modify ionic expressions associated to the excitability and electrical refractoriness of the cardiac tissue with the objective of hindering the maintenance of reentrant behaviors. These therapies require a deep knowledge of the ionic mechanisms underlying the reentrant behavior and its properties in order to be effective. The research in these mechanisms allows the evaluation of new targets for the treatment and thus may improve the efficacy in atrial fibrillation termination. In this thesis, mathematical modeling is used to go forward in the minimization of the limitations associated to these treatments. Body surface potential mapping has been evaluated, both clinically and by means of mathematical simulations for the diagnosis and location of macro-reentrant circuits. The analysis of phase maps obtained from multiple lead electrocardiographic recordings distributed in the whole torso allowed the discrimination between different reentrant circuits. It is the reason why this technique is presented as a tool for the non-invasive location of macro and micro-reentrant circuits. A population of mathematical models designed in this thesis based on the action potentials recordings of atrial cardiomyocites from 149 patients, allowed the evaluation of the ionic mechanisms defining the properties of reentrant behaviors. This study has allowed us defining the blockade of ICaL as a target for the pharmacological treatment. The blockade of this current is associated with the increase of the movement in the core of the rotor which easies the collision of the rotor with other wavefronts or anatomical obstacles promoting the extinction of the reentry. The variability observed between patients modeled in our population has allowed showing and explaining the mechanisms promoting divergent results of a single treatment. This is why the introduction of populations of models will allow the prevention of side effects associated to inter-subject variability and to go forward in the development of individualized therapies. These works are built through a simulation platform of cardiac electrophysiology based in Graphic Processing Units (GPUs) and developed in this thesis. The platform allows the simulation of cellular models, tissues and organs with a realistic geometry and shows features comparable to that of the platforms used by the most relevant electrophysiology research groups at the moment.
[ES] Las taquiarritmias auriculares tienen una alta prevalencia en el mundo desarrollado, además diversos estudios poblacionales indican que en las próximas décadas ésta se verá incrementada. Los mecanismos de micro o macro-reentrada de los frentes de onda eléctricos que rigen el comportamiento mecánico del corazón, se presentan como una de las principales causas del mantenimiento de estas arritmias. El flutter auricular es mantenido por un macro-reentrada alrededor de un obstáculo anatómico o funcional en las aurículas, mientras que en el caso de la fibrilación auricular la hipótesis que define a los rotores de alta frecuencia como elementos dominantes y responsables del mantenimiento de la arritmia se ha ido imponiendo al resto en los últimos años. Sin embargo, las terapias que tienen como objetivo finalizar o aislar estas reentradas tienen todavía una eficacia limitada. La ablación por radiofrecuencia permite eliminar zonas del tejido cardiaco resultando en la interrupción del circuito de reentrada en el caso de macro-reentradas o el aislamiento de comportamientos micro-reentrantes. La localización no invasiva de los circuitos reentrantes incrementaría la eficacia de estas terapias y reduciría la duración de las intervenciones quirúrgicas. Por otro lado, las terapias farmacológicas alteran las expresiones iónicas asociadas a la excitabilidad y la refractoriedad del tejido con el fin de dificultar el mantenimiento de comportamientos reentrantes. Este tipo de terapias exigen incrementar el conocimiento de los mecanismos subyacentes que explican el proceso de reentrada y sus propiedades, la investigación de estos mecanismos permite definir las dianas terapéuticas que mejoran la eficacia en la extinción de estos comportamientos. En esta tesis el modelado matemático se utiliza para dar un paso importante en la minimización de las limitaciones asociadas a estos tratamientos. La cartografía eléctrica de superficie ha sido testada, clínicamente y con simulaciones matemática,s como técnica de diagnóstico y localización de circuitos macro-reentrantes. El análisis de mapas de fase obtenidos a partir de los registros multicanal de derivaciones electrocardiográficas distribuidas en la superficie del torso permite diferenciar distintos circuitos de reentrada. Es por ello que esta técnica de registro y análisis se presenta como una herramienta para la localización no invasiva de circuitos macro y micro-reentrantes. Una población de modelos matemáticos, diseñada en esta tesis a partir de los registros de los potenciales de acción de 149 pacientes, ha permitido evaluar los mecanismos iónicos que definen las propiedades asociadas a los procesos de reentrada. Esto ha permitido apuntar al bloqueo de la corriente ICaL como diana terapéutica. Ésta se asocia al incremento del movimiento del núcleo que facilita el impacto del rotor con otros frentes de onda u obstáculos extinguiéndose así el comportamiento reentrante. La variabilidad entre pacientes reflejada en la población de modelos ha permitido además mostrar los mecanismos por los cuales un mismo tratamiento puede mostrar efectos divergentes, así el uso de poblaciones de modelos matemáticos permitirá prevenir efectos secundarios asociados a la variabilidad entre pacientes y profundizar en el desarrollo de terapias individualizadas. Estos trabajos se cimientan sobre una plataforma de simulación de electrofisiología cardiaca de basado en Unidades de Procesado Gráfico (GPUs) y desarrollada en esta tesis. La plataforma permite la simulación de modelos celulares cardiacos así como de tejidos u órganos con geometría realista, mostrando unas prestaciones comparables con las de las utilizadas por los grupos de investigación más potentes en el campo de la electrofisiología.
[CAT] Les taquiarítmies auriculars tenen una alta prevalença en el món desenvolupat, a més diversos estudis poblacionals indiquen que en les pròximes dècades aquesta es veurà incrementada. Els mecanismes de micro o macro-reentrada dels fronts d'ona elèctrics que regeixen el comportament mecànic del cor, es presenten com una de les principals causes del manteniment d'aquestes arítmies. El flutter auricular és mantingut per una macro-reentrada al voltant d'un obstacle anatòmic o funcional en les aurícules, mentre que en el cas de la fibril·lació auricular la hipòtesi que defineix als rotors d'alta freqüència com a elements dominants i responsables del manteniment de l'arítmia s'ha anat imposant a la resta en els últims anys. No obstant això, les teràpies que tenen com a objectiu finalitzar o aïllar aquestes reentrades tenen encara una eficàcia limitada. L'ablació per radiofreqüència permet eliminar zones del teixit cardíac resultant en la interrupció del circuit de reentrada en el cas de macro-reentrades o l'aïllament de comportaments micro-reentrants. La localització no invasiva dels circuits reentrants incrementaria l'eficàcia d'aquestes teràpies i reduiria la durada de les intervencions quirúrgiques. D'altra banda, les teràpies farmacològiques alteren les expressions iòniques associades a la excitabilitat i la refractaritat del teixit amb la finalitat de dificultar el manteniment de comportaments reentrants. Aquest tipus de teràpies exigeixen incrementar el coneixement dels mecanismes subjacents que expliquen el procés de reentrada i les seues propietats, la recerca d'aquests mecanismes permet definir les dianes terapèutiques que milloren l'eficàcia en l'extinció d'aquests comportaments. En aquesta tesi el modelatge matemàtic s'utilitza per a fer un pas important en la minimització de les limitacions associades a aquests tractaments. La cartografia elèctrica de superfície ha sigut testada, clínicament i amb simulacions matemàtiques com a tècnica de diagnòstic i localització de circuits macro-reentrants. L'anàlisi de mapes de fase obtinguts a partir dels registres multicanal de derivacions electrocardiogràfiques distribuïdes en la superfície del tors permet diferenciar diferents circuits de reentrada. És per açò que aquesta tècnica de registre i anàlisi es presenta com una eina per a la localització no invasiva de circuits macro i micro-reentrants. Una població de models matemàtics, dissenyada en aquesta tesi a partir dels registres dels potencials d'acció de 149 pacients, ha permès avaluar els mecanismes iònics que defineixen les propietats associades als processos de reentrada. Açò ha permès apuntar al bloqueig del corrent ICaL com a diana terapèutica. Aquesta s'associa a l'increment del moviment del nucli que facilita l'impacte del rotor amb altres fronts d'ona o obstacles extingint-se així el comportament reentrant. La variabilitat entre pacients reflectida en la població de models ha permès a més mostrar els mecanismes pels quals un mateix tractament pot mostrar efectes divergents, així l'ús de poblacions de models matemàtics permetrà prevenir efectes secundaris associats a la variabilitat entre pacients i aprofundir en el desenvolupament de teràpies individualitzades. Aquests treballs es fonamenten sobre una plataforma de simulació de electrofisiologia cardíaca basat en Unitats de Processament Gràfic (GPUs) i desenvolupada en aquesta tesi. La plataforma permet la simulació de models cel·lulars cardíacs així com de teixits o òrgans amb geometria realista, mostrant unes prestacions comparables amb les de les utilitzades per els grups de recerca més importants en aquesta área.
Liberos Mascarell, A. (2016). Mathematical modeling approaches for the diagnosis and treatment of reentrant atrial tachyarrhythmias [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62166
TESIS

Orientadores: Fabio Husemann Menezes, João Poterio Filho
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
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Resumo: Introdução- A gestação é considerada como fator de desenvolvimento de varizes nas pernas e um dos fatores supostamente responsável por isso, seria o aumento de pressão nas veias das pernas devido ao aumento do útero e compressão das veias ilíacas. Para avaliar a pressão nas veias das pernas em posição ortostática nos ambulatórios, o método considerado como padrão ouro, é a punção da veia diretamente, mas isso é inconveniente. Objetivos- O propósito desse estudo foi o de utilizar um método não invasivo para medir a pressão nas veias das pernas em posição ortostática; o estudo foi aplicado em um grupo controle, em um grupo de varicosos e em um grupo de gestantes no 3º trimestre da gestação e comparar os valores obtidos entre os grupos. Método- Foram selecionadas para o estudo, 24 mulheres gestantes (média das gestações de 29,7 semanas) que foram avaliadas e comparadas com um grupo de 20 pacientes com varizes e 20 pessoas de um grupo controle. Os três grupos foram submetidos a medida da pressão venosa nas pernas em posição ortostática por meio de um pletismógrafico a ar, usando transdutor diferencial de pressão; a medida da pressão encontrada foi comparada com o valor da pressão hidrostática calculada a partir do segundo espaço intercostal até o local de aplicação do manguito. Resultados- Não houve diferença estatística entre a pressão calculada nos três grupos. A média da pressão no grupo de gestantes foi de 63,5 mmHg ± 5,4 SD, e foi comparada com a pressão encontrada no grupo controle 66,1 mmHg ± 8,0 SD, (p=0.1851). A pressão medida no grupo de gestantes foi estatisticamente diferente da pressão medida no grupo das varicosas (71,0 mmHg ± 6,6 SD) ? p<0,0003). Conclusão- Não foi verificado no estudo atual aumento dos valores de pressão hidrostática nas veias das pernas no 3º trimestre da gestação
Abstract: Introduction- Pregnancy is a predisposing factor to the development of varicose veins of the lower legs. One of the possible explanations is the compression of the iliac veins by the enlarged uterus, leading to a raise in the venous pressure (VP) and consequently to the enlargement of the venous system at the legs. To evaluate the VP the gold standard is Ambulatory Venous Pressure measured b+y the venipuncture, but it is inappropriate. The purpose of this study is to measure the VP at the legs, in the standing position, in a control group, varicose women and in a group of women in the third trimester of pregnancy, using a new non-invasive technique. Method- Twenty-four pregnant women (mean pregnancy age 29.7 weeks) were evaluated and compared to a group of 20 patients presenting with varicose veins and a group of 20 control volunteers. The three groups were submitted to VP measurement in the standing position by means of air-plethysmography using a pressure differential transducer; the measured pressures (MP) were compared to the hydrostatic pressures calculated (CP) from the second intercostal space to the level of the leg cuff. Results- There was no statistic difference between the mean CP of the three groups. The mean MP in the pregnancy group was 63.5 mmHg ± 5.4 SD, and it was comparable to the MP of the normal volunteers, 66.1 mmHg ± 8.0 SD, (p = 0.1851). The MP of the pregnancy group was statistically different from the mean MP of the varicose veins group (71.0 mmHg ± 6.6 SD, -p<0.0003). Conclusion- There is no increase in the hydrostatic pressure in the leg veins at the end of pregnancy
Mestrado
Cirurgia
Mestre em Cirurgia

INTRODUÇÃO: A ecocardiografia tridimensional em tempo real (E3DTR) vem provando sua acurácia para quantificar os volumes do ventrículo esquerdo (VE), fração de ejeção (FEVE) e massa em pacientes com cardiomiopatia. Na cardiomiopatia hipertrófica (CMH), onde a morfologia ventricular pode estar muito alterada, a análise das estruturas cardíacas é fundamental para indicação da terapêutica ideal. A ressonância magnética cardiovascular (RMC) é um método superior na análise segmentar do VE em comparação a ecocardiografia bidimensional (E2D), mas com alta complexidade e existente em poucos centros diagnósticos, com contraindicações e limitações para a sua realização. MÉTODOS: Estudo transversal, comparativo, duplo cego, em 20 portadores de CMH, com E2D, E3DTR e RMC realizados com intervalo máximo de 06 meses e armazenados em formato digital. A espessura das paredes, volumes, função sistólica e massa ventricular esquerda foram analisados pelos métodos ecocardiográficos e pela RMC, assim como o movimento anterior sistólico da valva mitral, o índice geométrico do VE e o índice sistólico de dissincronia do VE. ANÁLISE ESTATÍSTICA: Análise estatística pelo coeficiente de concordância de Lin, correlação linear de Pearson e modelo de Bland-Altman. RESULTADOS: Foi obtida exeqüibilidade elevada acima de 94%, dependente do parâmetro avaliado. Concordância satisfatória e forte correlação linear evidenciada para a análise segmentar (Rc>0.84 e r>0.85; p<0.0001) observada para os métodos ecocardiográficos comparados à RMC, com concordância excelente entre os métodos ecocardiográficos (Rc=0,92 e r=0,92, p<0,0001). Concordância satisfatória e forte correlação linear para a fração de ejeção do VE (Rc=0.83 e r=0.93; p<0.0001) pela E3DTR comparada à RMC. Concordância excelente e forte correlação linear para o VDFVE e VSFVE pela E3DTR comparada à RMC e pela E2D comparada à E3DTR (Rc>0.90 and r>0.95; p<0.0001), assim como para a massa do VE, para os métodos E3DTR e RMC (Rc=0.96 e r=0.97; p<0.0001). Evidenciada maior exeqüibilidade da análise do MAS pela E3DTR. O índice geométrico do VE foi >0,15mmxm²xml-1 para todos os métodos. Observada correlação negativa entre o índice de dissincronia do VE e o percentual de fibrose miocárdica, sem significância estatística. CONCLUSÕES: A E3DTR é precisa e superior à E2D na avaliação da distribuição da hipertrofia miocárdica, quantificação dos volumes, função e massa ventricular esquerda em pacientes com CMH quando comparada à RMC, e parece ser superior na análise do MAS, pela melhor visão espacial da valva mitral.Todas as medidas do índice geométrico do ventrículo esquerdo estavam acima de 0,15mmxm²xml-1, compatível com CMH. Não foi identificada correlação entre o índice sistólico de dissincronia ventricular esquerda e a fibrose miocárdica.
INTRODUCTION: Real-time three-dimensional echocardiography (RT3D) has been demonstrated an accurate technique for the quantification of left ventricular (LV) volumes, ejection fraction (LVEF), and mass. In patients with hypertrophic cardiomyopathy (HCM), in which alterations of ventricular morphology are common, cardiac structural analysis is of utmost importance for guiding adequate therapy. Although magnetic resonance imaging (MRI) seems to have better definition for segmental analysis than two-dimensional echocardiography, (2D-E), it is considered a complex test with low availability and some limitations for use. METHODS: Comparative and double-blinded study in 20 patients with HCM. All patients underwent 2DE, RT3D and MRI within maximal interval of 6 months. Parameters analyzed by echocardiography and MRI included: wall thickness, LV volumes, systolic function, LV mass, systolic anterior motion of mitral valve, LV geometric index and LV dyssynchrony index. Statistical analysis was performed by Lin agreement coefficient, Pearson linear correlation and Bland-Altman model. RESULTS: Feasibility for measurements by MRI and echocardiography was 94%. There was good agreement and linear correlation between segmental analysis by echocardiography and MRI (Rc>0.84 and r>0.85; p<0.0001) and excellent correlation between 2DE and RT3DE (Rc=0.92 and r=0.92; p<0.0001). We also observed good agreement and linear correlation between RT3DE and MRI for ejection fraction (Rc=0.83 and r=0.93; p<0.0001) and excellent agreement and linear correlation between RT3DE and MRI for LV end diastolic volume and LV end systolic volume determinations (Rc>0.90 and r>0.95; p<0.0001) and mass (Rc=0.96 and r=0.97; p<0.0001). The feasibility for systolic anterior motion of mitral valve was higher by RT3DE (91%) than 2DE (64%). LV geometric index was >0.15 mmxm²xml-1 for all techniques. There was no correlation between LV dyssynchrony index and the percentage of myocardial fibrosis. CONCLUSIONS: RT3D is an accurate technique with superior performance than 2DE for the evaluation of myocardial hypertrophy localization, LV volume and functional determination as well as for LV mass assessment in patients with HCM in comparison with MRI. In addition, it seems to be superior for the analysis of systolic anterior motion due to its better spatial view of mitral valve. All measurements of LV geometric index were above the value of 0.15 mmxm²xml-1, and such findings are compatible with HCM. No correlation between LV dyssynchrony index by RT3D and the percentage of myocardial fibrosis determined by MRI was identified.

Thesis (MScMedSc)--University of Stellenbosch, 2011.
ENGLISH ABSTRACT: An important next step to Tuberculosis control relies on the translation of basic science and modern diagnostic techniques into primary health care clinics. These assays must be rapid, inexpensive, interpretation of results must be easy and they must be simple so that a healthcare worker with limited training can perform the tests under safe conditions. This study consists of four aims. The first aim was to develop a methodology to sterilize sputum specimens for rapid TB diagnosis and drug resistance testing. Candidate bactericides were identified from the literature, and tested for their bactericidal activity in Mycobacterium tuberculosis. We identified ultraseptin®aktiv as a powerful bactericidal agent which sterilizes sputum specimens for subsequent safe handling prior to light emitting diode microscopy and it also provides a DNA template for PCR-based tests. An algorithm has been proposed for the processing of specimens and rapid diagnosis of TB and drug resistant TB while patients wait for results. Recently, the World Health Organization has endorsed the MTBDRplus test for diagnosis of TB and drug resistant TB. However genotypic tests may have more problems than anticipated. With the HIV pandemic, an increase of non-tuberculous mycobacteria has been reported. The sensitivity of genotypic tests in specimens with underlying non-tuberculous mycobacterial species therefore requires further evaluation. This study therefore also aimed at determining the reliability of the MTBDRplus assay for detection of drug resistant TB where non-tuberculous bacterial load is high. Clinically relevant non-tuberculous mycobacterium DNA and DNA from a multi-drug resistant TB isolate were obtained. Ratios of the different NTM with the MDR-TB DNA were made and subjected to the MTBDRplus assay. Known mix NTM and TB infected clinical isolates and sputum sediments were also evaluated for TB and drug resistance detection on the MTBDRplus assay. Under these conditions, this study provides evidence that the MTBDRplus test cannot reliably detect TB and drug resistance TB in specimens with underlying non-tuberculous mycobacteria. Thirdly, to evaluate the sensitivity of the MTBDRplus assay for detecting drug resistance in hetero-resistant isolates, ratios were made using purified DNA from an MDR and pan-susceptible TB isolate. The MTBDRplus assay was then performed on the different ratios. We report that the MTBDRplus assay can efficiently detect wild type DNA in genes associated with resistance during the early evolution of drug resistance. However, in the later stage during treatment when both the wild type and mutants are present, the detection limit for the mutant DNA was 1:55. Due to these results, the MTBDRplus assay should still be further improved or other tests should be developed to address these limitations. And finally to combat cross amplicon contamination during the final steps of genotypic detection with the MTBDRplus assay, a proof of concept for a patentable closed tube line probe device was proposed on the 4th aim. This device can be improved to enable automated drug resistance genotyping of multiple specimens. The results of this study highlight the need for a sensitive inexpensive point of care drug resistance test that does not require intensive training.
AFRIKAANSE OPSOMMING: 'n Belangrike volgende stap om Tuberkulose te beheer is om basiese wetenskap resultate te gebruik sodat moderne diagnose tegnieke ontwikkel kan word wat in primêre gesondheidsorg klinieke toegepas kan word. Hierdie toetse moet vinnig, goedkoop, en die interpretasie van resultate moet maklik wees. Die toetse moet eenvoudig wees sodat 'n gesondheidswerker met beperkte opleiding die toetse onder veilige omstandighede kan uitvoer. Hierdie studie bestaan uit vier doelwitte, waarvan die eerste was om 'n metode te ontwikkel vir die sterilisasie van sputum monsters vir vinnige TB diagnose en die toesting van middelweerstandigheid. Kandidaat kiemdodende middels was geïdentifiseer vanaf die literatuur en die middels se kiekdodende aktiviteit was getoets op Mycobacterium tuberculosis. Ons het ultraseptin®aktiv geïdentifiseer as 'n kragtige kiemdodende middel wat bakteria in sputum monsters steriliseer vir veilige hantering voordat diagnose met 'n lig uitstralende diode mikroskopie gedoen kan word. Hierdie behandeling met ultraseptin®aktiv bied ook 'n DNA templaat vir PCR-gebaseerde toetse. 'n Algoritme is voorgestel vir die hantering van monsters en die vinnige diagnose van sensitiewe- en middel weerstandige Tuberkulose terwyl die pasiënte by die kliniek wag vir die resultate. Onlangs het die Wêreld Gesondheid Organisasie die genotipiese MTBDRplus toets vir die diagnose van Tuberkulose en middel-weerstandige Tuberkulose onderskryf. Hierdie toets word tans op groot skaal in Suid Afrika gebruik. Dit kan egter wees dat genotipiese toetse baie meer probleme kan he as wat aanvanklik verwag is. Die HIV pandemie gaan toenemend gepaard met n toename van nie-tuberkulose mycobacteria. Die sensitiwiteit van genotipiese toetse op monsters met onderliggende nie-tuberkulose mikobakteriese spesies vereis dus verdere evaluasie. Die doel van hierdie studie was ook om die betroubaarheid van die MTBDRplus-toets te bepaal vir die opsporing van middelweerstandige TB waar die nie-tuberkulose bakteriële lading hoog is. DNA van kliniese relevante nie-tuberkulose mikobakteria en multi-middelweerstige TB isolate was bekom. Verskillende verdunnigs van die spesifieke NTM DNA te same met die van MDR-TB DNA is gemaak en onderwerp aan die MTBDRplus toets. Bekende gemengde NTM- en TB geïnfekteerde kliniese isolate en sputum sedimente was ook geevalueer vir die opsporing van TB en middel weerstandigheid met die MTBDRplus toets. Hierdie studie verskaf bewyse dat die MTBDRplus toets nie betroubaar is met die diagnose van sensitiewe- en middel weerstandige Tuberkulose in monsters met onderliggende nie-tuberkulose mycobacteria nie. Verskillende verdunnings van gesuiwerde DNA van MDR en pan-sensitiewe TB isolate is gemaak om die sensitiwiteit van die MTBDRplus toets vir die opsporing van middelweerstandigheid te bepaal. Die MDRDRplus toets is gebruik met hierdie verdunnings. Resultate in hierdie studie toon dat die MTBDRplus toets effektief is met die identifisering van wilde-tipe DNA (dit beteken middel sensitief) in gene wat geassosieer word met middel weerstandigheid gedurende die vroeë ontwikkeling van weerstandigheid. Hier teenoor toon die resultate dat in die later stadium tydens behandeling, wanneer beide die wilde-tipe (sensitief) en mutante DNA (weerstandig) teenwoordig is, is die opsporingslimiet vir die mutante DNA maar 1:55. As gevolg van hierdie resultate raai ons aan dat die MTBDRplus toets nog verder verbeter moet word of dat ander toetse ontwikkel moet word om hierdie beperkinge aan te spreek. Amplikon kruiskontaminasie kan n groot impak hê op die betroubaarheid van enige genotipiese diagnostiese toets. Die finale stappe van MTBDRplus toets behels die gebruik van 'n oop sisteem sodat kontaminasie maklik kan plaasvind. In die 4de doewit 'n konsep vir 'n patenteerbare geslotebuis toestel ontwikkel en die resultate het getoon dat kontaminasie suksesvol uitgeskakel kan word. Hierdie toestel kan verbeter na 'n outomatiese apparaat verbeter word sodat die module genotipering van verskeie monsters moontlik kan maak. Die resultate van hierdie studie beklemtoon die noodsaaklikheid van 'n sensitiewe goedkoop “point of care” diagnostiese toets wat nie intensiewe opleiding benodig nie.
Medical Research Council of South Africa
University of Stellenbosch, Dept. of Molecular Biology and Human Genetics

A novel system has been simulated with accompanying experimental data that is designed to provide spatial information of elemental concentrations at biologically relevant levels. Using a deuterium-deuterium (DD) neutron generator, two large high-purity germanium (HPGe) detectors operating in tandem, and the associated particle imaging (API) technique, elemental iron concentrations as low as 100 ppm have been resolved in vivo in the liver of a simulated reference man with an equivalent dose to the region of interest of < 5 mSv and an estimated whole body dose of 0.82 mSv. Using the Monte Carlo Neutral Particle (MCNP) transport code, achievable spatial resolutions in the projective and depth dimensions of < 1 cm and < 3 cm are achievable, respectively, for iron-containing voxels on the order of 1,000 ppm Fe – with an overall 225 ps system timing resolution, 6.25 mm² imaging plate pixels, and a Gaussian-distributed DD neutron source spot with a diameter of 2 mm. Additionally, as a departure from Monte Carlo simulations, the underlying concepts of fast neutron inelastic scatter analysis as an initial surrogate to true associated particle neutron elemental imaging (APNEI) were demonstrated using a DD neutron generator, iron-made interrogation targets, a sodium iodide detector, and physical neutron/gamma shielding, which yielded an approximate detection limit for iron of 3.45 kg which was simulated to improve to 0.44 kg upon incorporation of the associated particle collimation methodology.

The API technique allows concentrations of elements such as iron to be quantified due to time-tagged electronic collimation and corresponding background signal reduction. Inherent to the API process is the collection of spatial and temporal information, which allows the perceived origin of a photon signal to be identified in 3D space. This process was modeled algorithmically in MCNP and employed using relevant equipment and shielding geometries. By leveraging the capabilities of modern-day neutron generator and coincident timing technologies with high throughput signal processing discrimination, the applicability of APNEI to disease diagnostics and etiological research is promising.

碩士
國立交通大學
電控工程研究所
101
Many clinical results and literatures revealed that the hyper-spectral imaging was widely applied to biomedical diagnosis. Nowadays, the operative steps of hyper-spectral devices for cancer detection were slicing the region of suspected lesions, and the pathologist observed the image information through the analysis of hyper-spectral instruments. The process must slice the lesions and caused the pain of patients. This thesis proposes an in vivo diagnostic method that utilizes the fiber endoscopic to capture the image of the oral tissue and then the image information is transmitted to the hyper-spectral instrument through the endoscope. The research develops two sets of diagnostic systems. The high-resolution fiber endoscopy combined with Embedding Relay Lens Hyper-spectral Image system (ERL-HSI). The system can simultaneous acquire 400nm to 1000nm spectral information and spatial image for analysis. For the clinical fast diagnosis, this study proposes a simple handheld device. The fluorescent image is excited by the UV light source and then passes through the selected spectral filter. Finally, the sensor acquires the specific band image for diagnosis. This study eventually develops the algorithm for diagnosing the oral cancer with high accuracy. In the experimental data of the fiber endoscope combined with hyper-spectral system, we find the spectral index of oral cancer using for algorithm. It reached 94% sensitivity and 93% specificity.

Prenatal diagnosis is an established obstetrics practice in many countries. Currently available methods to obtain fetal materials for a definitive diagnosis involve invasive procedures such as chorionic villus sampling and amniocentesis. Due to the invasive nature of the procedures, confirmatory testing is usually recommended only for pregnant women who are screened as being high risk of bearing a fetus with abnormalities. There has been an urge to develop safer alternatives in obtaining fetal genetic materials for prenatal assessment. Thus, the discovery of circulating fetal DNA in maternal plasma and serum has opened up new possibilities for noninvasive prenatal diagnosis.
The use of genetic markers such as Y chromosomal sequences from a male fetus or paternally-inherited polymorphic markers has been well-described in the literature. However, there is an obvious limitation on the use of these markers because they are gender- and/or polymorphism-dependent. This thesis focuses on the development of a universal fetal marker, namely SERPINB5 (encoding maspin), based on the intrinsic epigenetic differences between the placenta (the major contributor of fetal genetic materials in maternal plasma) and maternal blood cells (postulated to be the predominant source of cell-free DNA in the circulation). Analysis of the methylation profile of the SERPINB5 promoter in the placenta and maternal blood cells, and the development of methods and protocols to detect the differentially methylated SERPINB5 promoter molecules are described. The application of this epigenetic marker in prenatal assessment of the fetal chromosomal aneuploidy is illustrated by an epigenetic allelic ratio (EAR) approach. Basically, the ratio of a single-nucleotide polymorphism (SNP) on the placenta-derived SERPINB5 molecules is shown to be deviated in the maternal plasma from trisomic pregnancies when compared to the euploid ones. Results described in this thesis show the promising potential for the EAR approach for the noninvasive prenatal detection of fetal chromosomal aneuploidies. In addition, a novel approach for methylation analyses on the amplification and detection of restriction enzyme-digested DNA fragments will be discussed. This thesis has essentially described the evolution of a fetal epigenetic marker from basic science to potential clinical application.
Tong, Yu Kwan.
Adviser: Yuk-Ming Dennis Lo.
Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 0953.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2007.
Includes bibliographical references (leaves 149-172).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
School code: 1307.

Oral cancer is the 11th most common cancer in the world. Cancers of the oral cavity and oropharynx account for more than 7,500 deaths each year in the United States alone. Major advances have been made in the management of oral cancer through the combined use of surgery, radiotherapy and chemotherapy, improving the quality of life for many patients; however, these advances have not led to a significant increase in survival rates, primarily because diagnosis often occurs at a late stage when treatment is more difficult and less successful. Accurate, objective, noninvasive methods for early diagnosis of oral neoplasia are needed. Here a method is presented to noninvasively evaluate oral lesions using depth-sensitive optical spectroscopy (DSOS). A ball lens coupled fiber-optic probe was developed to enable preferential targeting of different depth regions in the oral mucosa. Clinical studies of the diagnostic performance of DSOS in 157 subjects were carried out in collaboration with the University of Texas M. D. Anderson Cancer Center. An overall sensitivity of 90% and specificity of 89% were obtained for nonkeratinized oral tissue relative to histopathology. Based on these results a compact, portable version of the clinical DSOS device with real-time automated diagnostic capability was developed. The portable device was tested in 47 subjects and a sensitivity of 82% and specificity of 83% were obtained for nonkeratinized oral tissue. The diagnostic potential of multimodal platforms incorporating DSOS was explored through two pilot studies. A pilot study of DSOS in combination with widefield imaging was carried out in 29 oral cancer patients, resulting in a combined sensitivity of 94% and specificity of 69%. Widefield imaging and spectroscopy performed slightly better in combination than each method performed independently. A pilot study of DSOS in combination with the optical contrast agents 2-NBDG, EGF-Alexa 647, and proflavine was carried out in resected tissue specimens from 15 oral cancer patients. Improved contrast between neoplastic and healthy tissue was observed using 2-NBDG and EGF-Alexa 647.

1997年，胎兒DNA被首次證實存在於母體血漿中。這一發現促進了無創產前診斷技術的發展。由於孕婦血漿中含大量來自母體的背景DNA，這給針對胎兒特異性DNA序列以外的產前診斷變得有挑戰性。近期開發的大規模平行測序技術把DNA定量精度提升到了一個空前的水平。本團隊已證實這一技術可應用於對胎兒染色體非整倍體和對胎兒全基因組的檢測。由於目前平行測序的費用仍相當昂貴，目標性測序技術可提高目標區域的數據比例從而降低測序成本。
在論文第一部分，本人論述了目標性測序在母體血漿DNA應用的可行性。本實驗採用雜交型富集技術對X染色體的外顯子進行富集。我們用平行測序比較了經由和未經富集處理的樣本。對比發現，經富集處理的樣本在目標區域的平均測序深度是未經富集處理樣本的213倍。目標區域的母體和胎兒DNA分子的富集程度相當。經富集處理後，目標區域的胎兒特異性等位基因的檢測率從3.5%提升至95.9%。
在論文第二部分，本人論述了目標性測序對胎兒21三體無創產前診斷的應用價值。我們對7，13，18和21號染色體上的單核苷酸多態性位點進行目標性測序。目標性測序數據顯示，在父源性21三體的樣本中，21號染色體上的胎兒特異性等位基因與共有性等位基因的比值上升約2倍。而在母源性21三體的樣本中，這一比值則下降約11%。本人採用電腦模擬實驗探討胎兒DNA濃度，有效等位基因數量和測序深度對檢測準確率的影響。
在論文第三部分，本人論述了目標性測序對胎兒單基因疾病無創產前診斷的應用。針對兩個需進行β地中海貧血產前診斷的家庭，我們對其β球蛋白基因進行目標性測序。我們用數字PCR技術推導了父母親β球蛋白基因區域的單倍型。經過相對性單倍型劑量分析，兩個胎兒的β地中海貧血遺傳狀況均得到了正確的推斷。其中一對夫婦位於致病區域的單倍型結構相近。
鑒於目標性測序技術可降低測序成本和提高目標序列的通量，其在血漿DNA的應用將有助於平行測序技術在無創性產前診斷、癌症診斷和移植監控等分子診斷學領域的發展。
The presence of fetal DNA in the cell-free plasma of pregnant women was first reported in 1997. This discovery has facilitated the development of noninvasive prenatal diagnosis. The coexistence in maternal plasma of a minor population of fetal DNA among a major background of maternal DNA has posed challenges for extending noninvasive prenatal diagnostic applications that require analytical information beyond the detection of fetus-specific DNA sequences. The recent availability of massively parallel sequencing has enhanced the precision of DNA quantification to an unprecedented level. Our group has demonstrated the application of massively parallel sequencing in noninvasive prenatal diagnosis of chromosomal aneuploidies, as well as genome-wide fetal whole genome sequencing and mutational profiling. While the current costs of massively parallel sequencing are relatively expensive, targeted massively parallel sequencing may enhance the cost-effectiveness compared with the non-targeted approach because it increases the proportion of informative data from the regions-of-interest.
In the first part of this thesis, I have demonstrated the feasibility of targeted massively parallel sequencing in maternal plasma DNA. In this proof-of-principle study, hybridization-based target enrichment was used to enrich exons on chromosome X. Plasma DNA libraries with and without target enrichment were analyzed by massively parallel sequencing. For the targeted regions, the mean sequencing depth of the enriched samples was 213-fold higher than that of the non-enriched samples. Maternal and fetal DNA molecules were enriched to similar extents within the targeted regions. With target enrichment, the detection rate of fetus-specific alleles within the targeted regions increased from 3.5% to 95.9%.
In the second part of this thesis, I have demonstrated the potential application of targeted massively parallel sequencing of plasma DNA for noninvasive prenatal diagnosis of trisomy 21 using an allelic ratio approach. Targeted sequencing was used to enrich single nucleotide polymorphism loci on chr7, chr13, chr18 and chr21. The targeted sequencing data showed that the ratio between fetus-specific and shared alleles increased by approximately 2-fold on chr21 in a paternally-derived trisomy 21 case, and decreased by approximately 11% on chr21 for maternally-derived trisomy 21 cases. I have also used computer simulation to determine the impact of fractional fetal DNA concentration, number of informative alleles and sequencing depth on the detection accuracy.
In the third part of this thesis, I have demonstrated the feasibility of targeted massively parallel sequencing of maternal plasma DNA for noninvasive prenatal diagnosis of monogenic diseases. Targeted sequencing was used to enrich the β-globin gene region in two families undergoing prenatal diagnosis for β-thalassemia. Parental haplotypes of the β-globin gene region were deduced via digital polymerase chain reaction. Relative haplotype dosage analysis was performed successfully to determine the β-thalassemic status for the fetuses, including one family in which the parents had similar haplotype structures in the disease-causing region.
Because of its potential to save costs and increase throughput, targeted sequencing may catalyse the translation of massively parallel sequencing based molecular diagnostics into many fields, including noninvasive prenatal diagnosis, cancer diagnostics and transplantation monitoring.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Detailed summary in vernacular field only.
Liao, Jiawei.
Thesis (Ph.D.)--Chinese University of Hong Kong, 2013.
Includes bibliographical references (leaves 147-155).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstracts also in Chinese.
ABSTRACT --- p.i
ACKNOWLEDGEMENTS --- p.vi
PUBLICATIONS --- p.vii
CONTRIBUTORS --- p.viii
TABLE OF CONTENTS --- p.ix
LIST OF TABLES --- p.xiii
LIST OF FIGURES --- p.xiv
LIST OF ABBREVIATIONS --- p.xvi
Chapter SECTION I : --- BACKGROUND --- p.1
Chapter CHAPTER 1: --- Cell-free fetal DNA and targeted massively parallel sequencing --- p.2
Chapter 1.1 --- Cell-free fetal DNA in maternal plasma --- p.2
Chapter 1.2 --- NIPD by qualitative analysis --- p.3
Chapter 1.2.1. --- Fetal sex assessment --- p.4
Chapter 1.2.2. --- RHD genotyping --- p.5
Chapter 1.2.3. --- Other implementations --- p.5
Chapter 1.3 --- NIPD by quantitative analysis --- p.6
Chapter 1.3.1. --- NIPD of chromosomal aneuploidies --- p.6
Chapter 1.3.2. --- NIPD of autosomal recessive monogenic diseases --- p.8
Chapter 1.4 --- Massively parallel sequencing of maternal plasma --- p.9
Chapter 1.4.1. --- Massively parallel sequencing --- p.9
Chapter 1.4.2. --- MPS-based NIPD of chromosomal aneuploidies --- p.11
Chapter 1.4.3. --- MPS-based prenatal fetal whole-genome scanning --- p.15
Chapter 1.5 --- Targeted massively parallel sequencing of maternal plasma --- p.19
Chapter 1.5.1. --- Microdroplet-based PCR --- p.19
Chapter 1.5.2. --- Molecular inversion probe --- p.20
Chapter 1.5.3. --- On-array capture --- p.21
Chapter 1.5.4. --- In-solution capture --- p.21
Chapter 1.5.5. --- Implementation on plasma DNA --- p.22
Chapter 1.6 --- Aims of this thesis --- p.29
Chapter SECTION II : --- Feasibility of targeted MPS in maternal plasma DNA --- p.30
Chapter CHAPTER 2: --- Targeted MPS of maternal plasma DNA permits efficient and unbiased detection of fetal alleles --- p.31
Chapter 2.1 --- Introduction --- p.31
Chapter 2.2 --- Methods --- p.34
Chapter 2.2.1 --- Study participants and sample collection --- p.34
Chapter 2.2.2 --- Sample processing and DNA extraction --- p.34
Chapter 2.2.3 --- DNA quantification --- p.36
Chapter 2.2.4 --- Microarray genotyping --- p.39
Chapter 2.2.5 --- Plasma DNA library preparation --- p.39
Chapter 2.2.6 --- Plasma DNA library validation --- p.40
Chapter 2.2.7 --- Target enrichment --- p.44
Chapter 2.2.8 --- Massively parallel sequencing and alignment --- p.45
Chapter 2.3 --- Results --- p.48
Chapter 2.3.1 --- Efficiency of target enrichment --- p.48
Chapter 2.3.2 --- Sequence coverage within the targeted region --- p.53
Chapter 2.3.3 --- Fetus-specific allele detection --- p.59
Chapter 2.3.4 --- Fractional fetal DNA concentrations before and after enrichment --- p.63
Chapter 2.4 --- Discussion --- p.66
Chapter SECTION III : --- NIPD of trisomy 21 by targeted MPS of maternal plasma DNA --- p.71
Chapter CHAPTER 3: --- NIPD of fetal trisomy 21 by allelic ratio analysis using targeted MPS of maternal plasma DNA --- p.72
Chapter 3.1 --- Introduction --- p.72
Chapter 3.2 --- Methods --- p.74
Chapter 3.2.1 --- Study participants and sample collection --- p.74
Chapter 3.2.2 --- Sample processing and DNA extraction --- p.74
Chapter 3.2.3 --- Targeted MPS of plasma DNA libraries --- p.74
Chapter 3.2.4 --- F-S ratio calculation --- p.76
Chapter 3.2.5 --- Microarray genotyping --- p.78
Chapter 3.2.6 --- Computer simulation --- p.78
Chapter 3.3 --- Results --- p.80
Chapter 3.3.1 --- Efficiency of target enrichment --- p.80
Chapter 3.3.2 --- Estimation of fractional fetal DNA concentrations --- p.83
Chapter 3.3.3 --- F-S ratio calculation using non-targeted sequencing data --- p.83
Chapter 3.3.4 --- F-S ratio calculation using targeted sequencing data --- p.85
Chapter 3.3.5 --- Computer simulation --- p.85
Chapter 3.4 --- Discussion --- p.90
Chapter SECTION IV : --- NIPD of monogenic diseases by targeted MPS of maternal plasma DNA --- p.94
Chapter CHAPTER 4: --- NIPD of monogenic diseases by targeted MPS of maternal plasma: application to Beta-thalassemia --- p.95
Chapter 4.1 --- Introduction --- p.95
Chapter 4.2 --- Methods --- p.98
Chapter 4.2.1 --- Sample collection and DNA extraction --- p.98
Chapter 4.2.2 --- Microarray-based genotyping --- p.100
Chapter 4.2.3 --- Targeted MPS of plasma DNA libraries --- p.100
Chapter 4.2.4 --- Genotyping by Sanger sequencing --- p.103
Chapter 4.2.5 --- Haplotyping by digital PCR --- p.105
Chapter 4.2.6 --- RHDO analysis --- p.105
Chapter 4.3 --- Results --- p.110
Chapter 4.3.1 --- Effectiveness of targeted sequencing --- p.110
Chapter 4.3.2 --- Determination of fetal HBB genotype in the first family --- p.112
Chapter 4.3.3 --- Determination of fetal HBB genotype in the second family --- p.113
Chapter 4.4 --- Discussion --- p.115
Chapter SECTION V : --- CONCLUDING REMARKS --- p.120
Chapter CHAPTER 5: --- Conclusion and future perspectives --- p.121
Chapter 5.1 --- Targeted MPS in plasma DNA --- p.121
Chapter 5.2 --- Targeted MPS in NIPD of chromosomal aneuploidies --- p.124
Chapter 5.3 --- Targeted MPS in NIPD of monogenic diseases --- p.126
Chapter Appendix I: --- Primer names and sequences for genotyping and haplotyping of βeta-globin gene cluster region --- p.128
Chapter Appendix II: --- Primers used in PCRs and sequencing for the parents in the first family --- p.132
Chapter Appendix III: --- Primers used in PCRs and sequencing for the parents in the second family --- p.138
Chapter Appendix IV: --- RHDO analysis on maternal plasma DNA in the first family --- p.140
Chapter Appendix V: --- RHDO analysis on maternal plasma DNA in the second family --- p.145
References --- p.147

Leong Hok Chong.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1998.
Includes bibliographical references (leaves 87-103).
Abstract also in Chinese.
Chapter 1. --- Abstract --- p.5
Chapter 2. --- Introduction --- p.8
Chapter 3. --- Noninvasive Methodology in Pulse Wave Assessment --- p.20
Chapter 3.1 --- Applanation Tonometry --- p.20
Chapter 3.2 --- The Instrument: Sphygmocardiograph --- p.20
Chapter 3.3.0 --- Reproducibility of Sphygmocardiograph --- p.27
Chapter 3.3.1 --- Background --- p.27
Chapter 3.3.2 --- Study Aims --- p.28
Chapter 3.3.3 --- Subjects and Methods --- p.28
Chapter 3.3.4 --- Statistical Analysis --- p.29
Chapter 3.3.5 --- Results --- p.31
Chapter 3.3.6 --- Discussion --- p.35
Chapter 4. --- Radial Artery-Derived Aortic Augmentation Indexin Normotensive Subjects --- p.36
Chapter 4.1 --- Background --- p.36
Chapter 4.2 --- Study Aims --- p.36
Chapter 4.3 --- Subjects and Methods --- p.38
Chapter 4.4 --- Statistical Analysis --- p.38
Chapter 4.5 --- Results --- p.39
Chapter 4.6 --- Discussion --- p.52
Chapter 5. --- Changes of Arterial Pulses in Normotensive Subjects with Family History of Hypertension --- p.56
Chapter 5.1 --- Background --- p.56
Chapter 5.2 --- Study Aims --- p.58
Chapter 5.3 --- Subjects and Methods --- p.58
Chapter 5.4 --- Statistical Analysis --- p.59
Chapter 5.5 --- Results --- p.59
Chapter 5.6 --- Discussion --- p.65
Chapter 6. --- Radial Artery-Derived Aortic Augmentation Indexin Hypertensive Subjects --- p.67
Chapter 6.1 --- Background --- p.57
Chapter 6.2 --- Study Aims --- p.68
Chapter 6.3 --- Subjects and Methods --- p.68
Chapter 6.4 --- Statistical Analysis --- p.69
Chapter 6.5 --- Results --- p.69
Chapter 6.6 --- Discussion --- p.70
Chapter 7. --- Changes of Arterial Pulses in Antihypertensive Therapies: Comparison between Diuretic and Long-Acting Calcium Antagonist --- p.72
Chapter 7.1 --- Background --- p.72
Chapter 7.2 --- Study Aims --- p.73
Chapter 7.3 --- Subjects and Methods --- p.73
Chapter 7.4 --- Statistical Analysis --- p.74
Chapter 7.5 --- Results --- p.74
Chapter 7.6 --- Discussion --- p.76
Chapter 8. --- General Remarks and Conclusion --- p.80
Chapter 9. --- Acknowledgments --- p.86
Chapter 10. --- References --- p.87

Chook Ping.
Publication date from spine.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1995.
Includes bibliographical references (leaves 72-96).
Chapter 1.0 --- Abstract --- p.1
Chapter 2.0 --- Introduction --- p.3
Chapter 3.0 --- Aim of Study --- p.7
Chapter 4.0 --- Patients and Methods --- p.7
Chapter 4.1.0 --- Patients and Preparations --- p.7
Chapter 4.2.0 --- Ultrasound Machine --- p.8
Chapter 4.3.0 --- B-mode Ultrasound Imaging --- p.10
Chapter 4.3.1 --- Artery Anatomy --- p.10
Chapter 4.3.2 --- Interface of Arterial Wall --- p.11
Chapter 4.3.3 --- B-mode Ultrasound Image Orientation --- p.12
Chapter 4.3.4 --- B-mode Ultrasound Scanning Procedure --- p.13
Chapter 4.3.5 --- Classification of Atherosclerotic Lesion --- p.16
Chapter 4.4.0 --- Training of Sonographer --- p.28
Chapter 4.5.0 --- Reproducibility of B-mode Ultrasonography --- p.28
Chapter 4.6.0 --- Statistical Evaluation --- p.29
Chapter 5.0 --- Results --- p.31
Chapter 5.1.0 --- Assessment of Training of Sonographer --- p.31
Chapter 5.2.0 --- Reproducibility of Two Ultrasonic Measurements --- p.31
Chapter 5.2.1 --- Intimal-Media Thickness --- p.31
Chapter 5.2.2 --- Lumen Diameter --- p.32
Chapter 5.3.0 --- Clinical Relevance --- p.43
Chapter 5.3.1 --- Patient's Characteristics --- p.43
Chapter 5.3.2 --- Relation of Intimal-Media Thickness to Disease and Age Groups --- p.43
Chapter 5.3.3 --- Prevalence of Atherosclerosis --- p.44
Chapter 5.3.4 --- Extent of Atherosclerosis --- p.45
Chapter 6.0 --- Discussion --- p.59
Chapter 7.0 --- General Remarks and Conclusion --- p.70
Chapter 8.0 --- Acknowledgment --- p.71
Chapter 9.0 --- References --- p.72

Trabalho Final do Mestrado Integrado em Medicina apresentado à Faculdade de Medicina
Noninvasive prenatal testing (NIPT) brought into obstetrics the unprecedented ability to access the fetal genome with a noninvasive technique. Currently, this technique’s most reliable application is in prenatal screening for trisomy 21. Several studies comparing its performance with traditional maternal serum screening have been published in the last decade, showing its potential in improving overall aneuploidy detection rate, reducing the need for invasive diagnostic procedures (IDP) and broadening our ability to explore fetal genetic features. Its reliable performance and noninvasive nature have resulted in its inclusion in many different prenatal screening models worldwide. However, the use of NIPT in prenatal care does not obviate the need for a confirmatory IDP after a positive test result. The existence of a significant number of discordant and “no call” test results justifies the need for a confirmatory IDP. Pregnancy, maternal and fetal-related conditions may be the reason for these discordant results. In addition, it is important to highlight its limitations regarding congenital conditions other than the most common trisomies, where ultrasound, traditional serum screening and IDP still play an irreplaceable role. Health care providers are thus responsible for recognizing the test’s limitations and interpreting its results, as well as defining situations where NIPT may not be the most adequate screening test..........................................................................................................
O teste pré-natal não invasivo trouxe à obstetrícia uma capacidade única de aceder ao genoma fetal de forma não invasiva. Atualmente, a aplicação mais bem aceite é o rastreio pré-natal da trissomia 21. Vários estudos comparando o seu desempenho com o tradicional rastreio bioquímico no sangue materno têm sido publicados na última década, mostrando o seu contributo superior na taxa de deteção das aneuploidias mais comuns, reduzindo o número de procedimentos invasivos de diagnóstico realizados e alargando o nosso espectro de análise do genoma fetal. O seu desempenho promissor e natureza não invasiva têm levado à sua introdução em diferentes modelos de rastreio pré-natal por todo o mundo. Contudo, o recurso ao teste pré-natal não invasivo não descarta a necessidade subsequente de realização de um procedimento invasivo de diagnóstico confirmatório, após a obtenção de um resultado positivo no teste não invasivo. Este facto é justificado pela existência de um número significativo de resultados discordantes e 'no-call' results. Características próprias da gravidez, maternas ou fetais podem ser a causa desses erros. É importante sublinhar a sua limitação no rastreio de condições congénitas que vão além das trissomias mais comuns, onde os métodos de rastreio e diagnóstico tradicionais ainda desempenham um papel preponderante. Os profissionais de saúde são, por isso, responsáveis por reconhecer as limitações deste teste e interpretar os seus possíveis resultados, assim como definir situações em que o teste pré-natal não invasivo pode não ser o método de rastreio mais adequado a ser aplicado.

In the first part of this thesis, two chromosome Y specific genes ( SRYand TSPY) were chosen as the molecular targets to investigate the characteristics of fetal-specific DNA fragments in maternal plasma. By employing the touch down ligation-mediated PCR coupled with cloning and sequencing, the end property and the fragment species of fetal DNA were studied.
Noninvasive prenatal detection of fetal chromosomal aneuploidies is a much sought-after goal in fetomaternal medicine. The discovery of fetal DNA in the plasma of pregnant women has offered new opportunities for this purpose. However, the fact that fetal DNA amounts to just a minor fraction of all DNA in maternal plasma makes it challenging for locus-specific DNA assays to detect the small increase in sequences derived from a trisomic chromosome. On the other hand, although the clinical applications of plasma DNA for prenatal diagnosis are expanding rapidly, the biological properties of circulating DNA in plasma remain unclear. Recently, next-generation sequencing technologies have transformed the landscape of biomedical research through the ultra-high-throughput sequence information generated in a single run. Massively parallel sequencing allows us to study plasma DNA at an unprecedented resolution and also precisely detect fetal chromosomal aneuploidies in a locus-independent way.
Our group has demonstrated the use of massively parallel sequencing to quantify maternal plasma DNA sequences for the noninvasive prenatal detection of fetal trisomy 21. In the second part of this thesis, the clinical utility of this new sequencing approach was extended to the prenatal detection of fetal trisomy 18 and 13. A region-selection method was developed to minimize the effects of GC content on the diagnostic sensitivity and precision for the prenatal diagnosis of trisomy 13. To facilitate the next-generation sequencing-based maternal plasma DNA analysis for clinical implementation, two measures, i.e., lowering the starting volume of maternal plasma and barcoding multiple maternal plasma samples, were investigated.
Taken together, the results presented in this thesis have demonstrated the clinical utility of massively parallel sequencing of maternal plasma DNA and have also provided us a better understanding of the biology of circulating DNA molecules.
The third part of this thesis focuses on the massively parallel paired-end sequencing of plasma DNA. By analyzing millions of sequenced DNA fragments, the biological properties of maternal plasma DNA were elucidated, such as the size distribution of fetal-derived and maternally-contributed DNA molecules and the potential effect of epigenetic modification on DNA fragmentation. Moreover, the plasma DNA from hematopoietic stem cell transplant patients was characterized by paired-end sequencing approach. These sequencing data not only confirmed the predominant hematopoietic origin of cell-free DNA but also revealed the size difference between hematologically-derived and other tissue-derived DNA molecules in plasma.
Zheng, Wenli.
Adviser: Lo Yu Ming Dennis.
Source: Dissertation Abstracts International, Volume: 73-03, Section: B, page: .
Thesis (Ph.D.)--Chinese University of Hong Kong, 2010.
Includes bibliographical references (leaves 261-275).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.

The use of noninvasive imaging technologies has recently changed the clinical approach to diagnosis and management of skin cancers, becoming an essential tool in daily dermatological practice. The present research focused on new applications of noninvasive imaging techniques, namely: a) evaluation of clinical and dermoscopic criteria of nevus-associated melanoma (NAM); b) assessment of the accuracy of dermoscopy, compared to clinical examination, in the detection of borders of basal cell carcinoma (BCC) and description of the most common dermoscopic findings in the clinically healthy tissue surrounding BCC, in case of not-matching clinically and dermoscopically detected margins; c) evaluation of the diagnostic accuracy of electrical impedance spectroscopy in the diagnosis of actinic keratosis (AK) and subclinical lesions in comparison to the naked eye examination and dermoscopy. Concerning NAM, different clinical and dermoscopic features of melanomas associated with congenital or non-congenital nevi and their correlation with specific patients’ characteristics were discovered. As regards BCC, dermoscopic findings in the area between clinically and dermoscopically detected margins were described, which are useful to better define the actual tumor margins and achieve a really radical excision. Finally, the possible usefulness of electrical impedance spectroscopy in the management of AKs was evaluated, obtaining preliminary data of good sensitivity but low specificity, likely open to improvement in the future. These results confirm the pivotal role of noninvasive imaging in both diagnostic and therapeutic phase of dermato-oncology, and suggest possible additions and/or changes to currently employed criteria.

As the global burden of liver disease evolves, a need for noninvasive detection and diagnosis has emerged. For over fifty years biopsy has been the standard to which all other disease detection and confirmation methods have been compared. With the development of several noninvasive methods in the detection of liver disease, biopsy has come under scrutiny for its cost-effectiveness, reliability and safety. Serologic testing has proven useful but not specific overall for the determination of disease stages. Liver stiffness is a relatively new parameter used in the diagnosis and monitoring of hepatic disease. It is a quantifiable through the use of an ultrasound-based method of transient elastography using a tool Fibroscan. The implementation of transient elastography has changed the paradigm of liver disease diagnostics with a more cost effective, reproducible, reliable, and well-tolerated option. While the hepatitis C virus is the primary cause of fibrosis and cirrhosis, numerous studies of the application of liver stiffness measurement to varying disease etiologies have broadened the scope of the method. Optimizing reliability criteria has been the focus of many studies to find a standard by which cirrhosis may be ruled out and fibrosis staging may be accomplished. Novel non-interferon based HCV therapies are altering the course of disease progression and may affect the need for continued development of noninvasive monitoring procedures. However, globally the impact of advanced liver disease is rising with an increase in mortality by fifty million cases per year from 1990-2010 indicating the continued relevance and need for widely applicable noninvasive procedures for both diagnosing hepatic disease and informing treatment options.

碩士
國立交通大學
材料科學與工程學系奈米科技碩博士班
107
It is always an important issue on prevention and diagnosis for human diseases. As medical technology advances, life expectancy on humans is longer than before. Therefore, the early detection of diseases is more critical. Among the top 10 causes of death globally, over half of the causes are derived from chronic diseases. Thus, how to detect and diagnose chronic diseases in early stages is a main research topic from now on. Tumor necrosis factor-α (TNF-α), a key member of cytokines, is a meditator of inflammation in immune system. The present study was focused on the fabrication of a biosensor which can detect the biomarker TNF-α through the application of a supramolecular hydrogel and aptamer for early diagnosis of chronic disease. First, we synthesized a novel hydrogel, 2-Naphthylacetic acid- L-Phenylalanine- L-Phenylalanine (Nap-FF), which was based on Napthyl acetic moiety by liquid phase synthesis strategy, and investigated its characteristic and the condition of hydrogelation. To capture and assess the cytokines TNF-α which was related to inflammation, the combination of hydrogel and the TNF-α aptamer (VR11) which was modified by amino group was used. In addition, the effects of gelation were observed and analyzed after the target TNF-α was added. Finally, we constructed a detecting system of TNF-α’s concentration assessment. In our sensing system, the specificity between the aptamer and its corresponding target plays an important role. When the aptamer VR11 which connected to hydrogel Nap-FF in two terminal sites captured TNF-α, its formation would change and let the hydrogel stacked together. Thus, the π-π interaction would increase, and so would the strength of the hydrogel. Moreover, the white points would be appeared. By means of the strengthening of hydrogelation and the difference of transmittance because of the white points, the concentration of TNF-α could be inferred easily and rapidly.

碩士
高雄醫學大學
醫學研究所
88
The most pulmonary embolism, which owns the potential fetal risk, results from deep venous thrombosis, especially the proximal limb. Incorrect diagnosis and inadequent treatment of deep venous thrombosis always results in chronic postphlibitc syndrome. Contrast venography, the diagnostic gold standard for deep venous thrombosis, has a deal of clinical practicle disadvantage. In recent years, noninvased image modalities become the image choice for diagnosis of clinical suspected (proximal) deep venous thrombosis. Since 1999, Jan to 2000, May, 81 lower limb swelling patients with clinical suspected deep venous thrombosis, have received both image examinations of Tc99m PYP RBCs SC-RNV and compression, color Doppler ultrasonography to identify proximal deep venous thrombosis. The average age of patients is 56.5+-3.5 year-old (the range of age from 8 to 97 year-old) and the ratio of female to male is 2:5. The underline diseases of our patients are including cancer, systemic vascular disorders, trauma, major surgery, and blood coagulant disorders. Little amout of stannous chloride was first injected subcutaneously for each limb which was tied with tourniquet above the ankle joint.. As soon as possible, the flow-dynamic half-body image, from foot to diaphrgram, was acquired by Gamma camera (Toshiba GCA 90B or ADAC vertex; LEGP, collimator). Then, the next half-body image for blood pool static study was proceeded after release the tourniquet. At the same time, compression ultrasonograph was performed with 5.0 MHz linear probe (Acuson 128). The pressure applied with transducer to collapse a normal vein was sufficient to cause minimal dimpling of the skin (approximately 10 4 dynes/cm2). The patient was initially placed in the supine position for evaluation of common femoral and superficial femoral veins. Then popliteal vein was assessed as prone position. Intraluminal diameter, echogenicity and compressibility of vessels were seen carefully. The color Doppler ultrasonography for evaluation of deep vascular flow provided hemodynamic information and assist the diagnosis of deep venous thrombosis. We found 33 patients, diagnosed as unilateral proximal deep venous thrombosis among 81 sympatic patients by compression ultrasonography. However, the sensivity and specificity of flow dynamic study of subcutaneous radionuclide venography are 78.7%, 89.1% for diagnosis of proximal deep venous thrombosis, seperately. The blood pool static study provides more higher sensivity and specificity, as 93.9 % and 86.0 % for diagnosis of proximal deep venous thrombosis. However, the diagnostic acurracy of combined both studies reaches 92.6%. Because of half-body image of radionuclide venography, there were 14 cases with extensively decreased or nonvisualized iliac venous radioactivity in the 33 patients. The incident ratio of deep venous thrombosis in the left lower limb is about one and half time than right side. Both images not only diagnose the proximal deep venous thrombosis, but also provide the differential diagnosis for swelling legs, such as focal "cold" lesion of hematoma, active "hot" arthritis, Baker's cysts, and diffusely increased vascularity in soft tissue with cellulitis. In conclusion, Tc99m PYP RBCs SCRNV has highly concordant with compression ultrasonography to identify the proximal deep venous thrombosis and provides whole venous hemodynamic situation on the half-body image.

Worldwide, head and neck squamous cell cancers (HNSCC) account for over 375,000 deaths annually. The majority of these cancers arise in the outermost squamous cells which progress through a series of precancerous changes before developing into invasive HNSCC. It is widely accepted that prognosis is strongly correlated to the stage of diagnosis, with early detection more than doubling the patient’s chance of survival. Currently, however, 60% of HNSCCs are diagnosed when they have already progressed to stage 3 or stage 4 disease. The current diagnostic method of visual examination often fails to recognize early indicators of HNSCC, thereby missing an important prevention window.

Determination of cancer from non-malignant tissues is dependent on pathological examination of lesion biopsies. Thus, all patients with any clinically suspicious lesions undergo surgical biopsies. Furthermore, these surgical biopsies carry risks. In addition to the risk of general anesthesia for patients undergoing panedoscopy, some patients have poor healing and develop ulcerations or infections as a result of surgical biopsy at any anatomical site. Additionally, studies have shown that approximately 50% of suspected biopsies are later pathologically confirmed normal. An enormous amount of labor, facility, and monetary resources are expended on non-malignant biopsies and patients who ultimately have no malignancy. It would be of immense overall benefit to clinicians and patients to have a non-invasive and portable technique that could rapidly identify those patients that would benefit from further surgical biopsy from those that only need follow-up clinical observations.

Once carcinoma is confirmed in a patient, treatment currently involves modalities of surgery, radiation, and chemotherapy. Radiotherapy plays a significant role, particularly in the management of localized HNSCC, because it is a non-invasive and function-preserving modality. However, the effectiveness of radiotherapy is limited by hypoxia. Previous studies showed that tumors reoxygenated during radiotherapy treatment may have a better prognosis. Despite decades of work, there is still no reliable, cost-effective way for measuring tumor hypoxia over multiple time points to estimate the prognosis.

To address these unmet clinical needs, three aims were proposed. The first aim was to improve early detection by identifying biomarkers of early pre-cancer as well as developing an objective algorithm to detect early disease. Neovasculature is an important biomarker for early cancer diagnosis. Even before the development of a clinically detectable lesion, the tumor vasculature undergoes structural and morphological changes in response to oncogenic signaling pathways [8]. Without receiving a sufficient supply of oxygen and nutrients to proliferate, early tumor growth is limited to only 1-2 mm. High-resolution optical imaging is well suited to characterize the earliest neovascularization changes that accompany neoplasia owing to its sensitivity to hemoglobin absorption and resolution to visualize capillary level architecture. Dark field microscopy is a low-cost and robust method to image the neovasculature. We imaged neovascularization in vivo in a spontaneous hamster oral mucosa carcinogen model using a label-free, reflected-light spectral dark field microscope. Hamsters’ cheek pouches were painted with 7, 12-Dimethylbenz[a]anthracene (DMBA) to induce precancerous to cancerous changes, or mineral oil as control. Spectral dark field images were obtained during carcinogenesis and in control oral mucosa, and quantitative vascular features were computed. Vascular tortuosity increased significantly in oral mucosa diagnosed as hyperplasia, dysplasia and squamous cell carcinoma (SCC) compared to normal. Vascular diameter and area fraction decreased significantly in dysplasia and SCC compared to normal. The areas under the receiver operative characteristic (ROC) curves (AUC) computed using a Support Vector Machine (SVM) were 0.95 and 0.84 for identifying SCC or dysplasia, respectively, vs. normal and hyperplasia oral mucosa combined. To improve AUCs for identifying dysplasia, quantitative vascular features were computed again after the vessels were split into large and small vessels based on diameter. The large vessels preserved the same significant trends, while small vessels demonstrated the opposite trends. Significant increases in diameter and decreases in area fraction were observed in SCC and dysplasia. The AUCs were improved to 0.99 and 0.92 for identifying SCC and dysplasia. These results suggest that dark field vascular imaging is a promising tool for pre-cancer detection.

Optical imaging can also be applied to quantifying other important characteristics of solid tumors in head and neck cancer (HNC), such as hypoxia, abnormal vascularity and cell proliferation. Diffuse reflectance spectroscopy is a simple and robust method to measure tissue oxygenation, vascularity and cell density. It is particularly suitable for applications in the operation room because of its compact design and portability. In addition, a fiber probe-based system is ideal for obtaining measurements at suspicious lesions in the head and neck area during surgery. Thus, my second aim was to reduce the number of unnecessary HNSCC biopsies by developing a robust tool and rapid analysis method appropriate for clinical settings. We propose the use of morphological optical biomarkers for rapid detection of human HNSCC by leveraging the underlying tissue characteristics in the aerodigestive tracts Prior to biopsy, diffuse reflectance spectra were obtained from malignant and contra-lateral non-malignant tissues of 57 patients undergoing panendoscopy. Oxygen saturation (SO2), total hemoglobin concentration ([THb]), and the reduced scattering coefficient were extracted using an inverse Monte Carlo (MC) method previously developed by former student in our lab. Differences in malignant and non-malignant tissues were examined based on two different groupings: by anatomical site and by morphological tissue type. Measurements were acquired from 252 sites, 51 of which were pathologically classified as SCC. Optical biomarkers exhibited statistical differences between malignant and non-malignant samples. Contrast was enhanced when parsing tissues by morphological classification rather than by anatomical subtype for unpaired comparisons. Corresponding linear discriminant models using multiple optical biomarkers showed improved predictive ability when accounting for morphological classification, particularly in node-positive lesions. The false-positive rate was retrospectively found to decrease by 34.2% in morphologically- vs. anatomically-derived predictive models. In glottic tissue, the surgeon exhibited a false-positive rate of 45.7% while the device showed a lower false-positive rate of only 12.4%. Additionally, comparisons of optical parameters were made to further understand the physiology of tumor staging and potential causes of high surgeon false-positive rates. Optical spectroscopy is a user-friendly, non-invasive tool capable of providing quantitative information to discriminate malignant from non-malignant head and neck tissues. Predictive models demonstrated promising results for diagnostics. Furthermore, the strategy described appears to be well suited to reduce the clinical false-positive rate.

To further improve the speed for extracting the tissue oxygenation and [THb] to reduce the time when patients were under anesthesia, the third aim was to develop a rapid heuristic ratiometric analysis for estimating tissue [THb] and SO2 from measured tissue diffuse reflectance spectra. The analysis was validated in tissue-mimicking phantoms and applied to clinical measurements in head and neck, cervical and breast tissues. The analysis works in two steps. First, a linear equation that translates the ratio of the diffuse reflectance spectra at 584 nm to 545 nm to estimate the tissue [THb] using a Monte carlo (MC)-based lookup table was developed. This equation is independent of tissue scattering and oxygen saturation. Second, SO2 was estimated using non-linear logistic equations that translate the ratio of the diffuse reflectance spectra at 539 nm to 545 nm into the tissue SO2. Correlations coefficients of 0.89 (0.86), 0.77 (0.71) and 0.69 (0.43) were obtained for the tissue hemoglobin concentration (oxygen saturation) values extracted using the full spectral MC and the ratiometric analysis, for clinical measurements in head and neck, breast and cervical tissues, respectively. The ratiometric analysis was more than 4000 times faster than the inverse MC analysis for estimating tissue [THb] and SO2 in simulated phantom experiments. In addition, the discriminatory power of the two analyses was similar. These results show the potential of such empirical tools to rapidly estimate tissue hemoglobin and oxygenation for real-time applications.

In addition to its use as a diagnostic marker for various cancers, tissue oxygenation is believed to play a role in the success of cancer therapies, particularly radiotherapy. However, since little effort has been made to develop tools to exploit this relationship, the fourth aim was to estimate patient prognosis by measuring tumor hypoxia over multiple time points so physicians are able to develop more informed and effective clinical treatment plan. To test if oxygenation kinetics correlates with the likelihood for local tumor control following fractionated radiotherapy, we again used diffuse reflectance spectroscopy to noninvasively measure tumor vascular oxygenation and [THb] associated with radiotherapy of 5 daily fractions (7.5, 9 or 13.5 Gy/day) in FaDu xenografts. Spectroscopy measurements were obtained immediately before each daily radiation fraction and during the week after radiotherapy. SO2 and [THb] were computed using an inverse MC model. Oxygenation kinetics during and after radiotherapy, but before a change in tumor volume, was associated with local tumor control. Locally controlled tumors exhibited significantly faster increases in oxygenation after radiotherapy (days 12-15) compared with tumors that recurred locally. (2) Within the group of tumors that recurred, faster increases in oxygenation during radiotherapy (days 3-5) were correlated with earlier recurrence times. An AUC of 0.74 was achieved when classifying the local control tumors from all irradiated tumors using the oxygen kinetics with a logistic regression model. (3) The rate of increase in oxygenation was radiation dose dependent. Radiation doses ≤9.5 Gy/day did not initiate an increase in oxygenation whereas 13.5 Gy/day triggered significant increases in oxygenation during and after radiotherapy. Additional confirmation is required in other tumor models, but these results suggest that monitoring tumor oxygenation kinetics could aid in the prediction of local tumor control after radiotherapy.

Angiogenesis is a highly regulated process to support tissue growth. Neovasculature is designed by nature to grow toward areas lacking nutrition and oxygen. Cancer cells proliferate too quickly to have their nutritional and oxygen needs completely satisfied, which results in an imbalanced state of angiogenesis leading to tortuous blood vessels, hypoxic tissues and radioresistance. We characterized the tumor-induced vascular features with simple, robust and low-cost dark field microscopy and spectroscopy to enable early cancer diagnosis, improvement of surgical biopsy accuracy and better predict the prognosis of radiotherapy for HNC. Our results demonstrated that these noninvasively measured, label-free vascular features are able to detect pre-cancer, reduce unnecessary surgical biopsies and predict prognosis of radiotherapy.

Dissertation