Literatura académica sobre el tema "Humour Vitrous"
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Artículos de revistas sobre el tema "Humour Vitrous"
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Orii, Yusuke, Eriko Kunikane, Yutaka Yamada, Masakazu Morioka, Kentaro Iwasaki, Shogo Arimura, Akemi Mizuno y Masaru Inatani. "Brimonidine and timolol concentrations in the human vitreous and aqueous humors after topical instillation of a 0.1% brimonidine tartrate and 0.5% timolol fixed-combination ophthalmic solution: An interventional study". PLOS ONE 17, n.º 12 (1 de diciembre de 2022): e0277313. http://dx.doi.org/10.1371/journal.pone.0277313.
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Purpose To evaluate the concentrations of brimonidine and timolol in the vitreous and aqueous humors after instillation of a 0.1% brimonidine tartrate and 0.5% timolol fixed-combination ophthalmic solution. Methods This single-arm open-label interventional study included patients with macular holes or idiopathic epiretinal membranes who were scheduled for vitrectomy. Written informed consent was obtained from all participants. A 0.1% brimonidine tartrate and 0.5% timolol fixed-combination ophthalmic solution was administered topically twice daily for 1 week preoperatively. The vitreous and aqueous humors were sampled before vitrectomy, and brimonidine and timolol concentrations were quantified using liquid chromatography-tandem spectrometry. This study was registered with the Japan Registry of Clinical Trials (jRCT, ID jRCTs051200008; date of access and registration: April 28, 2020). The study protocol was approved by the University of Fukui Certified Review Board (CRB) and complied with the tenets of the Declaration of Helsinki. Results Eight eyes of eight patients (7 phakic eyes and 1 pseudophakic eye) were included in this study. The mean brimonidine concentrations in the vitreous and aqueous humors were 5.04 ± 4.08 nM and 324 ± 172 nM, respectively. Five of the eight patients had brimonidine concentrations >2 nM in the vitreous humor, which is necessary to activate α2 receptors. The mean timolol concentrations in the vitreous and aqueous humors were 65.6 ± 56.0 nM and 3,160 ± 1,570 nM, respectively. Brimonidine concentrations showed significant positive correlations with timolol concentrations in the vitreous humor (P < 0.0001, R2 = 0.97) and aqueous humor (P < 0.0001, R2 = 0.96). Conclusions The majority of patients who received a 0.1% brimonidine tartrate and 0.5% timolol topical fixed-combination ophthalmic solution showed a brimonidine concentration >2 nM in the vitreous humor. Brimonidine and timolol may be distributed in the ocular tissues through an identical pathway after topical instillation.
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Mochizuki, Kiyofumi, Akira Sawada, Shinsuke Suemori, Hideaki Kawakami, Yoshiaki Niwa, Yuji Kondo, Kiyofumi Ohkusu et al. "Intraocular Penetration of Intravenous Micafungin in Inflamed Human Eyes". Antimicrobial Agents and Chemotherapy 57, n.º 8 (20 de mayo de 2013): 4027–30. http://dx.doi.org/10.1128/aac.02300-12.
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ABSTRACTEight eyes of 7 patients with fungal disease received intravenous injections of 150 to 300 mg micafungin, and samples of blood, cornea, retina-choroid, aqueous humor, and vitreous humor were collected. The micafungin levels in all collected samples exceeded the MICs; however, the levels in the vitreous and aqueous humors were lower. Our findings suggest that intravenous micafungin should be given in combination with intravitreal antifungal agents after vitrectomy in severe cases of intraocular fungal diseases.
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Semoun, Oudy, Sandrine Marchand, Nicolas Grégoire, Isabelle Lamarche, Christophe Adier, Laurent Laroche, Pablo Goldschmidt y William Couet. "Modeling Approach To Characterize Intraocular Doripenem Pharmacokinetics after Intravenous Administration to Rabbits, with Tentative Extrapolation to Humans". Antimicrobial Agents and Chemotherapy 56, n.º 7 (23 de abril de 2012): 3531–34. http://dx.doi.org/10.1128/aac.06329-11.
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ABSTRACTThe aim of this study was to determine the penetration of doripenem administered intravenously into the rabbit aqueous and vitreous humors. Nineteen New Zealand White rabbits received a 20-mg dose of doripenem intravenously over 60 min. Specimens of aqueous humor, vitreous humor, and blood were obtained 30 min (n= 5), 1 h (n= 5), 2 h (n= 5), and 3 h (n= 4) after the beginning of the infusion and analyzed by high-performance liquid chromatography (HPLC). A pharmacokinetic (PK) model was developed to fit the experimental data. Doripenem concentrations in aqueous humor were lower than those in plasma ultrafiltrates at all sampling times, with an average aqueous humor-to-plasma ultrafiltrate area under the concentration-time curve ratio estimated as 8.3%. A pharmacokinetic model with peripheral elimination described the data adequately and was tentatively used to predict concentration-versus-time profiles and pharmacokinetic-pharmacodynamic (PK-PD) target attainment in patients under various dosing regimens. In conclusion, systematically administered doripenem does not seem to be a promising approach for the treatment of intraocular infections, especially since it could not be detected in the vitreous humor. However, this study has provided an opportunity to develop a new PK modeling approach to characterize the intraocular distribution of doripenem administered intravenously to rabbits, with tentative extrapolation to humans.
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Piette, M. "The Effect of the Post-Mortem Interval on the Level of Creatine in Vitreous Humour". Medicine, Science and the Law 29, n.º 1 (enero de 1989): 47–54. http://dx.doi.org/10.1177/002580248902900107.
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By means of 103 medico-legal autopsies it was established that a rise in the creatine level occurs in the vitreous humour after death. In view of the satisfactory correlation between the post-mortem interval and the creatine level in the vitreous humour (r = 0.84, p < 0.001) investigations were undertaken as to whether the creatine level in vitreous humour can serve in current medico-legal practice as an indication for the post-mortem interval, especially for the later period (more than three days). On balance this creatine determination is only useful when combined with all other medico-legal parameters that establish the time of death, remembering that the confidence-interval in the investigations was rather wide.
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Silva, Andreia F., Manuel A. Alves y Mónica S. N. Oliveira. "Rheological behaviour of vitreous humour". Rheologica Acta 56, n.º 4 (7 de febrero de 2017): 377–86. http://dx.doi.org/10.1007/s00397-017-0997-0.
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Bergandi, Loredana, Oleksii A. Skorokhod, Rosalba La Grotta, Evelin Schwarzer y Raffaele Nuzzi. "Oxidative Stress, Lipid Peroxidation, and Loss of Hyaluronic Acid in the Human Vitreous Affected by Synchysis Scintillans". Journal of Ophthalmology 2019 (30 de octubre de 2019): 1–8. http://dx.doi.org/10.1155/2019/7231015.
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The aim of this study was to assess the oxidative stress status in eyes affected by synchysis scintillans and to compare it to vitreoretinal disorders without synchysis scintillans. Human aqueous and vitreous humors were obtained during vitrectomy from thirty-seven otherwise healthy patients that were randomly chosen among patients that had to undergo a 25-gauge pars plana vitrectomy from the central vitreous cavity, for either synchysis scintillans (n = 16) or vitreoretinal disorders without synchysis scintillans (n = 21), such as idiopathic epimacular membrane (n = 12), macular hole (n = 5), or rhegmatogenous retinal detachment (n = 4). The redox parameters thiobarbituric acid reactive substances (TBARS), a measurement of lipid peroxidation, nitrite concentration, an estimate of nitric oxide (NO) production, 4-hydroxynonenal (4-HNE)-protein conjugates, a structural protein modification by lipid peroxidation product 4-HNE, and the antioxidative activities of Cu,Zn-superoxide dismutase (SOD), and catalase were measured in aqueous and vitreous humors and compared between synchysis scintillans affected and not-affected patients. TBARS and nitrite levels of the vitreous humor were significantly higher in patients with synchysis scintillans as compared to patients affected by vitreoretinal disorders without synchysis scintillans. Synchysis scintillans patients had significantly lower activities of SOD and catalase both in aqueous and vitreous humors than patients with vitreoretinal disorders without synchysis. The consequently higher lipoperoxide-dependent 4-HNE production in synchysis scintillans was detectable in aqueous and vitreous humors as a significant increased accumulation of 4-HNE-protein conjugates vs nonsynchysis vitreoretinal disorders. Additionally, hyaluronic acid (HA) was significantly decreased in the vitreous body of synchysis scintillans patients. The data consistently show that synchisis scintillans is accompanied by a redox imbalance with increased oxidative modifications of 4-HNE proteins and loss of HA, both of likely importance for remote damages of the retina. It remains to be proven whether a therapeutic strategy which targets oxidative stress may be effective in the treatment of synchysis patients.
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Bennett, Michael J., Marie C. Ragni, Ian Hood y Daniel E. Hale. "Comparison of Post-Mortem Urinary and Vitreous Humour Organic Acids". Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 29, n.º 5 (septiembre de 1992): 541–45. http://dx.doi.org/10.1177/000456329202900509.
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We have analysed organic acid profiles in 74 samples of post-mortem vitreous humour from the suddent infant death syndrome and compared the profiles to those obtained from the corresponding urine or bladder wall swab. There was a high degree of correlation indicating that vitreous humour analysis in high-risk infants is an appropriate analytical strategy when urine is not available. In our patient sample two infants had evidence of abnormal methylmalonic acid metabolism, one had glyceric aciduria (and elevated levels of vitreous humour glyceric acid), one had evidence of pre-existing liver damage as judged by the presence of 4-hydroxyphenyllactic acid, one had a non-ketotic dicarboxylic aciduria indicating inhibited fatty acid oxidation and two patients had significant long-chain 3-hydroxydicarboxylic acids and evidence of paracetamol ingestion.
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Yip, David C. P. "Vitreous humor alcohol". Forensic Science International 73, n.º 2 (mayo de 1995): 155. http://dx.doi.org/10.1016/0379-0738(95)01727-z.
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ABDELKAWI, SALWA A. "THE RHEOLOGICAL PROPERTIES OF VITREOUS HUMOR AFTER Q-SWITCHED Nd:YAG LASER PHOTO DISRUPTION". Biophysical Reviews and Letters 07, n.º 01n02 (junio de 2012): 29–39. http://dx.doi.org/10.1142/s179304801250004x.
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This work aimed to study the photo disruptive effect of a Q-switched Nd:YAG laser with two different energy protocols on the rheological properties of the vitreous humor after treatment of posterior vitreous detachment (PVD). Twenty-one New Zealand albino rabbits were used in this study and divided into three groups. One group was used as control (n = 6 eyes), the second group (n = 18) was treated with Q-switched Nd:YAG laser energy of 5 mJ × 100 pulse (× means times) delivered to the anterior, middle and posterior vitreous respectively (n = 6 eyes for each). The third group (n = 18 eyes) was treated with 10 mJ × 50 pulse delivered to the anterior, middle and posterior vitreous respectively (n = 6 eyes for each). After two weeks, the protein content, refractive index (RI) and the rheological properties of vitreous humor were determined. The protein content, refractive index, consistency, shear stress and viscosity were increased especially for irradiation of the mid-vitreous, and posterior vitreous. The flow index remained below unity indicating the non-Newtonian behavior of the vitreous humor. Application of Q-switched Nd:YAG laser on mid-vitreous and posterior vitreous induce deleterious effect on the gel state of the vitreous humor.
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Lutty, G. A., R. J. Mello, C. Chandler, C. Fait, A. Bennett y A. Patz. "Regulation of cell growth by vitreous humour". Journal of Cell Science 76, n.º 1 (1 de junio de 1985): 53–65. http://dx.doi.org/10.1242/jcs.76.1.53.
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Extracts of normal vitreous have been found to inhibit angiogenesis in two animal models: tumour-induced neovascularization in the rabbit corneal micropocket and retinal extract-induced angiogenesis in the chick chorioallantoic membrane assay. Using in vitro assays, we have found recently that an extract of bovine vitreous, free of hyaluronic acid, inhibits proliferation of cells in the aortic wall, i.e. endothelium and smooth muscle cells, as well as capillary and corneal endothelium. The inhibition is dose-dependent, as determined by either cell count or [3H]thymidine incorporation, and not due to cytotoxicity, as demonstrated with a double-label thymidine assay. The inhibitor is trypsin-sensitive and heat-stable (95 degrees C for 10 min). Conversely, proliferation of pericytes, lens epithelium and fibroblasts (dermal and corneal) was stimulated by the vitreous extract. This mitogenic activity was heat-labile. Growth of pigment epithelium and several tumour cell lines was unaffected. The data demonstrate that normal vitreous contains a heat-stable growth inhibitor specific for endothelium and smooth muscle cells, and a non-specific heat-labile mitogen. The paradoxical effect of this antiangiogenic factor on arterial and capillary contractile cells, smooth muscle and pericytes, suggests a basic difference in the regulation of the two vasculatures. The results suggest that a substance in normal vitreous may be important in controlling neovascularization that results from diabetic and other retinopathies, and could be useful for inhibiting tumour-induced angiogenesis.
Tesis sobre el tema "Humour Vitrous"
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Cafferata, Chiara. "Investigations on vitreous humour dynamics". Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3421873.
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The vitreous humour is the substance that fills the posterior chamber. The vitreous body ensures the adherence of the retina to the underlying layers and acts as a barrier for heat and drug transport between the anterior and the posterior segments of the eye. In the medical literature many authors have postulated the existence of a connection between the fluid dynamics within the vitreous chamber during eye movements (especially when the substance filling the chamber is a liquid) and the occurrence of the retinal detachment.
In the present PhD Thesis the vitreous humour dynamics is studied by means of both an experimental and a numerical point of view.
The experiments consist in the measurement of the velocity field on the equatorial plane of a magnified model of the vitreous chamber using PIV techniques. The vitreous chamber has been modeled by means of a cavity carved in a rigid Perspex container. Two different geometries were used: a spherical geometry and a deformed geometry, which closely resembles that of the real eye. The model is filled with Glycerol, a highly viscous Newtonian fluid, and it is mounted on the shaft of a computer controlled motor, which rotates according to a generic time law. Visualizations of the fully three-dimensional flow show that the primary flow occurs on planes perpendicular to the axis of rotation. Secondary flows can be detected, the magnitude of which is however three or four orders smaller than the primary flow. In the case of spherical geometry, theoretical results, based on a simplified solution, are shown to be in very good agreement with the experimental findings. The maximum value of the shear stress at the wall does not significantly depend on the amplitude of saccadic
movements but is strongly influenced by the vitreous viscosity. Velocity fields are found to be strongly influenced by the deformed geometry of the domain. When using the deformed model the formation of a vortex in the vicinity of the lens is invariably observed. The path described by this vortex during a
period of oscillation is found to depend on the Womersley number of the flow. The second part of the Thesis is devoted to the formulation of a numerical model which provides a direct numerical simulation of the flow of a viscous fluid inside an oscillating sphere. The problem is formulated in the primitive velocity-pressure form. Replacing the continuity equation by the Poisson equation for the pressure supported by an independent condition of integral character an uncoupled formulation of the problem is derived. The equations are discretized in time by means of a non-fractional-step scheme. A spectral technique is used to transform the original problem in a sequence of ordinary differential problems for the coefficients of a spherical harmonics expansion of the variables. Spectral techniques have been tested on a simplified problem providing encouraging results.L’umor vitreo `e la sostanza che riempie la camera posteriore dell’occhio. Esso assicura l’aderenza della retina agli strati sottostanti e costituisce una barriera per il trasporto di calore o sostanze tra la camera anteriore e la camera posteriore dell’occhio. Molti autori nella letteratura medica hanno ipotizzato una connessione tra la dinamica del vitreo durante i movimenti oculari (specialmente nei casi in cui la sostanza che riempie la camera `e un liquido) e l’insorgenza del distacco retinico. Nella presente Tesi di Dottorato lo studio della dinamica del vitreo oculare `e stato affrontato secondo un approccio sperimentale e numerico. Gli esperimenti hanno riguardato la misura dei campi di moto che si realizzano sul piano equatoriale di un modello in scala amplificata della camera vitrale attraverso l’utilizzo della tecnica PIV. La camera vitreale `e stata modellata per mezzo di una cavit`a ricavata in un contenitore rigido di perspex. I contenitori usati hanno due diverse geometrie: una sferica e una sferica deformata che riproduce verosimilmente la reale conformazione della camera. Il modello `e stato riempito con glicerina, un fluido newtoniano ad elevata viscosit`a, e montato sull’albero di un motore che `e stato fatto ruotare secondo una generica legge di tipo. Attraverso visualizzazioni del moto tridimensionale si `e osservato come il moto principale si sviluppi su piani ortogonali all’asse di rotazione. Sono stati anche osservati moti secondari la cui intensit`a risulta essere di tre-quattro ordini di grandezza inferiori al moto principale. Nel caso di modello sferico i risultati sperimentali sono stati confrontati con una teoria semplificata mostrando un buon accordo con quest’ultima. Il massimo valore della tensione tangenziale`e risultato non dipendere in modo significativo dall’ampiezza del movimento ma di essere influenzato dalla viscosit`a del fluido interno alla camera. I campi di moto sono fortemente influenzati dalla geometria del dominio. Usando il contenitore deformato in tutti gli esperimenti `e stata osservata la formazione di un vortice. Il percorso descritto dal vortice durante un periodo di oscillazione `e risultato dipendere dal numero di Womersley del moto. La seconda parte della Tesi `e dedicata alla formulazione di un modello numerico consistente in una simulazione numerica diretta del moto di un fluido viscoso all’interno di una sfera oscillante. Il problema `e formulato nelle variabili primitive pressione-velocit`a. Sostituendo l’equazione di continuit`a con l’equazione di Poisson per la pressione, associata ad una condizione al contorno indipendente di tipo integrale, si `e ricavata una formulazione disaccoppiata dl problema. Le equazioni sono state discretizzate nel tempo per mezzo di uno schema non frazionario. Il problema originale `e stato trasformato attraverso una tecnica spettrale in una sequenza di problemi alle derivate ordinarie per i coefficienti di espansione in armoniche sferiche delle variabili del problema. Le tecniche spettrali sono state testate per la soluzione di un problema semplificato fornendo risultati confortanti.
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Bévalot, Fabien. "Intérêts et limites de la bile et de l'humeur vitrée comme matrices alternatives en toxicologie médicolégale". Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10362/document.
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Ce travail avait pour objectif d'étudier l'intérêt et les limites de l'analyse de deux matrices alternatives que sont la bile et l'humeur vitrée (HV), en toxicologie médicolégale. Pour chacune des deux matrices, une revue de la littérature visait à investiguer les connaissances utiles à leur application en toxicologie médicolégale. Une place importante de ces revues est réservée à l'anatomie et la physiologie de l'HV et du système biliaire ainsi qu'aux mécanismes de distribution des xénobiotiques dans ces matrices. La partie expérimentale décrit trois études: deux menées sur populations autopsiques et une associant expérimentations animales et études de populations autopsiques. Les deux premières ont permis de proposer des outils statistiques d'interprétation des concentrations de méprobamate mesurées dans ces matrices. Ils peuvent être utilisés dans diverses situations à la place ou en complément de l'interprétation des concentrations sanguines: cadavre exsangue, putréfaction avancée du corps, redistribution post mortem des xénobiotiques… La troisième étude concernait six molécules (diazépam, citalopram, cyamémazine, morphine, caféine et méprobamate). Les molécules détectées dans le sang l'étaient systématiquement dans l'HV et la bile aussi bien dans les prélèvements des populations autopsiques que ceux issus des expérimentations animales. Les concentrations vitréennes chez l'animal et chez l'homme étaient systématiquement corrélées aux concentrations sanguines, exceptées celles de cyamémazine et de citalopram chez l'homme. Pour la bile, une corrélation significative était observée pour le méprobamate et la caféine chez l'homme et l'animal. Il ressort de ces résultats, que l'analyse de l'HV et de la bile permettent de disposer d'informations relatives à la nature des molécules absorbées et à leur rôle dans la survenue du décèsThe present study sought to assess the interest and limitations of analyzing two alternative matrices, bile and vitreous humor (VH), in forensic toxicology. For each matrix, a literature review established the state of knowledge relating to their forensic application. The review placed special focus on the anatomy and physiology of VH and the biliary system and the mechanisms of xenobiotic distribution within the specific matrix. The experimental sections describe three studies: two performed on autopsy populations, and one associating autopsy populations to an animal model. The first two studies resulted in statistical tools for interpreting meprobamate concentrations in these matrices, which can be used as alternatives or complements to blood concentrations in various situations: exsanguination, advanced putrefaction, postmortem xenobiotic redistribution, etc. The third study focused on 6 molecules: diazepam, citalopram, cyamemazine, morphine, caffeine and meprobamate. Molecules detected in blood were also systematically detected in VH and bile samples from both the autopsy and animal populations. Animal VH and blood levels showed systematic correlation. In autopsy samples, cyamemazine and citalopram showed no such correlation. In bile, significant correlations with blood concentrations were found for meprobamate and caffeine in both the autopsy and animal populations. This study confirmed the interest of postmortem analysis of bile and VH. Results show that analyzing bile and VH sheds light on drugs intake and on their implication in cause of death
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Morris, Janine M. "A biophysical study into the mammalian vitreous humour and investigations into replacements". Thesis, University of East Anglia, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445210.
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Silva, Andreia F. "Rheological characterisation and numerical flow simulation of the human eye vitreous humour fluid". Thesis, University of Strathclyde, 2018. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=29428.
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In this work, the dynamics of vitreous humour (VH) and of a range of pharmacological fluids used to replace VH in eye surgery were investigated, both experimentally and numerically. Vitreous humour is a gel-like viscoelastic material that fills the majority of the ocular globe. Age-related changes occur in the VH, and as a consequence VH becomes progressively liquefied with age, which has an impact on the corresponding rheological properties, and leads to the appearance of vitreoretinal pathologies. The most effective treatment for such diseases is the injection of a VH substitute in the vitreous cavity. Most of the vitreous substitutes commercially available are silicone oils (SiO) and perfluorocarbon liquids (PFLC), but so far none of them proven to be used as a permanent substitute. The results of the rheological characterisation of the VH and pharmacological fluids under shear and extensional flow conditions are presented in the first part of this thesis. Vitreous humour samples were obtained from New Zealand specimen rabbit eyes, whereas the pharmacological fluids were purchased from two different pharmaceutical companies. Two distinct VH phases were analysed: a liquid and a gel phase. The average surface tension measured for the VH liquid phase was 47.8 mN/m, at T = 21 ± 2 °C. Steady shear experiments demonstrated that VH liquid phase has a pronounced shear-thinning behaviour. Small amplitude oscillatory shear (SAOS) experiments showed that both gel and liquid VH phases present a solid-like behaviour, which is more dominant in the gel phase, and these results were corroborated by creep experiments. Experiments with the VH liquid phase under extensional flow yielded an average relaxation time of λ = 9.7 ms, at T ≈ 37 °C. None of the pharmacological fluids tested showed a rheological behaviour close to the VH. The PFLCs and SiO-based fluids exhibit a Newtonian behaviour, with the exception of Siluron 2000 fluid, which under extensional flow presents a relaxation time of λ = 6.8 ms, at T ≈ 20 °C. The PFLCs have viscosities close to the viscosity of water, whereas the SiO-based fluids present viscosities between 0.73 and 4.57 Pa s, at T = 37 °C. Surface tension experiments showed that the PFLCs present lower values than the SiO-based fluids, and that the surface tension of the VH liquid phase is more than double of that measured for each of the pharmacological fluids tested. In contact with VH liquid phase from rabbit eyes, all the pharmacological fluids tested yielded interfacial tensions around 30 mN/m. The dynamic response of VH during saccadic movements was studied numerically using the opensource software OpenFOAM®. A comparative study between the VH and pharmacological fluids was performed for a saccadic movement with an amplitude of 40°. The numerical results showed that the VH liquid and gel phases present distinct behaviour. The shear stresses at the walls for the VH gel phase are higher than those produced by the VH liquid phase. This shows that the phase balance in VH significantly affects the flow dynamics of the biofluid. The numerical results also showed that velocity and wall shear stress (WSS) profiles are significantly different for VH and pharmacological fluids, revealing that the latter are unable to mimic accurately the VH flow behaviour in conditions such as those experienced during saccadic eye movements. Finally, different degrees of saccadic movements were studied and the numerical results showed that, for all the fluids investigated, the momentum diffusion across the vitreous cavity and the WSS increase with the increase of the saccadic movement amplitude. The new experimental results provided in this thesis, complemented by the dynamic behaviour computed numerically for saccadic eye movements, offer new insights for the improvement and development of new VH substitutes to be used in eye surgery, with particular focus on their mechanical functionality.
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Goto, Aline Yoshie. "Estudo da produção, composição e drenagem dos meios oculares de Carassius auratus (Cyprinidae) variedades padrão e demekin". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/47/47135/tde-22022017-115235/.
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O peixe dourado é extensivamente utilizado em pesquisas sobre visão devido a diversos fatores: é um animal pecilotermo, o que possibilita manter sua retina ex-vivo viável para manipulação experimental por mais tempo; apresenta uma organização retiniana semelhante à de mamíferos; possui neurônios grandes, facilitando estudos eletrofisiológicos e morfológicos e, diferentemente de mamíferos, é dotado de neurogênese constante de alguns tipos celulares retinianos. A produção, composição e escoamento dos meios oculares nesta espécie, fundamentais para a formação de imagens sobre a retina, são, entretanto, pouco conhecidos. A variedade padrão desta espécie apresenta desenvolvimento ocular normal, enquanto a variedade demekin é extremamente míope por possuir crescimento ocular exagerado (buftalmia), condição característica de alguns tipos de glaucoma em mamíferos. O presente trabalho investigou aspectos morfofisiológicos do sistema de produção e drenagem do humor aquoso e a composição do humor vítreo nestas duas variedades de peixe dourado, com o objetivo de melhor compreender as causas subjacentes ao crescimento ocular do demekin. Para estudar a drenagem do humor aquoso, foram realizadas injeções de corante na câmara anterior de animais das duas variedades, com processamento histológico posterior em intervalos de tempo pré-determinados (5, 15, 30, 60, 120 minutos e 1, 2, 3 4 e 7 dias, n <= 3 olhos de cada variedade por grupo experimental). Não foram observadas diferenças na drenagem de humor aquoso entre as duas variedades. Em ambas, o humor aquoso é drenado principalmente pela malha trabecular contida na porção ventral do ângulo de drenagem, entre a íris e o ligamento anular. Duas vias secundárias de drenagem foram encontradas nas duas variedades de peixe dourado estudadas: (i) a via irídica e (ii) a drenagem através de vasos epirretinianos. Estas vias são aparentemente mais lentas do que a via trabecular, uma vez que foi encontrado corante nessas regiões até quatro dias após as injeções de corante na câmara anterior. Foi realizado também estudo ultraestrutural da retina e epitélio ciliar em ambas as variedades através de microscopia eletrônica de transmissão. O epitélio pigmentado da retina do demekin apresentou grânulos de melanina mais escassos, e observamos certa desorganização da camada de fotorreceptores, bem como redução da sua densidade. Através de aparato invasivo construído por Joselevitch e Smith (1997), foi mensurada a pressão intraocular (PIO) de 14 olhos de cada variedade. O demekin apresentou valores de PIO ligeiramente aumentados em relação ao animal padrão (3,6 ± 0,9 mmH2O para o demekin e 1,9 ± 0,6 mmH2O para o peixe dourado padrão). A composição proteica do corpo vítreo foi estudada através de eletroforese em gel de poliacrilamida utilizando um pool de humor vítreo de 4 animais da variedade padrão e 2 da variedade demekin. As proteínas de baixa massa molecular (entre 15 a 25 kDa) estavam expressas em ambas - embora com maior expressão na variedade padrão - e outras, de maior massa molecular, expressas apenas no humor vítreo do demekin (50-75 kDa e 150 kDa). Os resultados obtidos sugerem, portanto, que há diferenças importantes na ultraestrutura retiniana, na composição proteica do humor vítreo e na pressão intraocular do demekin. Para melhor compreensão do crescimento ocular desta variedade faz-se necessária a realização de um estudo proteômico, identificando quais são as proteínas do humor vítreo evidenciadas através da eletroforese, bem como estudos morfológicos em animais de diferentes tamanhos visando a quantificação dos danos retinianos decorrentes do seu crescimento ocularThe goldfish is extensively used in vision research due to several factors: it is a poikilothermic animal, which allows ex-vivo experiments using its retina for longer periods of time; its retinal organization is very similar to that of mammals; it has large neurons, which facilitates electrophysiological and morphological studies and, unlike mammals, it is endowed with constant neurogenesis of some retinal cell types. However, the production, composition and outflow of ocular media in this species, which are fundamental for image formation onto the retina, are poorly understood. The standard goldfish has normal eye development, while the Black Moor goldfish is extremely myopic due to excessive eye growth (buphthalmos), a condition that is present in certain types of mammalian glaucoma. The present study investigated morphophysiological aspects of the aqueous humor production and drainage system and vitreous humor composition in these two varieties of goldfish to better understand the causes underlying the eye growth of the Black Moor. To study the drainage of the aqueous humor, anterior chamber dye injections and histological processing were performed in animals of both varieties after predetermined time intervals (5, 15, 30, 60, 120 minutes and 1, 2, 3, 4, and 7 days, n <= 3 eyes of each variety for each experimental group). No differences were observed in the drainage of aqueous humor between the two varieties. In both, the aqueous humor is drained mainly by the trabecular meshwork contained in the ventral portion of the drainage angle, between the iris and the annular ligament. Two secondary drainage routes were found in the two goldfish varieties studied: (i) the iridic route and (ii) drainage through epiretinal vessels. These pathways are apparently slower than the trabecular route, since the dye was found in these regions 4 days after the injections. An ultrastructural study of the retina and ciliary epithelium was also carried out in both varieties through transmission electron microscopy. The retinal pigment epithelium of the Black Moor presented more scarce melanin granules and we observed some disorganization of the photoreceptor layer, as well as a reduction in its density. Through an invasive device constructed by Joselevitch and Smith (1997), the intraocular pressure (IOP) of 14 eyes of each variety was measured. The Black Moor presented slightly increased IOP values compared to the standard animal (3.6 ± 0.9 mmH2O for demekin and 1.9 ± 0.6 mmH2O for the standard goldfish). The protein composition of the vitreous body was studied by polyacrylamide gel electrophoresis using a vitreous humor pool of 4 animals of the standard variety and 2 of the Black Moor variety. Low molecular weight proteins (15 to 25 kDa) were expressed in both - although with greater expression in the standard variety - and others of higher molecular mass, expressed only in the vitreous humor of the Black Moor (50-75 kDa and 150 kDa). These results suggest, therefore, that there are important differences in the retinal ultrastructure, the protein composition of the vitreous humor and the intraocular pressure of the Black Moor. To better understand the ocular growth in this variety, it is necessary to carry out a proteomic study, identifying which are the vitreous humor proteins evidenced through electrophoresis, as well as morphological studies in animals of different sizes aiming the quantification of the retinal damages caused by its ocular growth
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Atluri, Harisha Mitra Ashim K. "Part I: Vitreous disposition of alcohols as a function of lipophilicity part II: transporter mediated delivery of acycloguanosine antivirals to retina /". Diss., UMK access, 2004.
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Thesis (Ph. D.)--School of Pharmacy and Dept. of Chemistry. University of Missouri--Kansas City, 2004."A dissertation in pharmaceutical sciences and chemistry." Advisor: Ashim K. Mitra. Typescript. Vita. Description based on contents viewed Feb. 22, 2006; title from "catalog record" of the print edition. Includes bibliographical references (leaves 156-188). Online version of the print edition.
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Peres, Mariana Dadalto. "Humor vítreo: uma alternativa para investigação de drogas de abuso postmortem". Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/60/60134/tde-12052015-112035/.
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O humor vítreo (HV) é um gel aquoso, transparente e incolor, situado entre o cristalino e a retina. Ele pode ser uma ferramenta para determinação de drogas de abuso, sobretudo quando é impossível fazer a determinação em sangue devido à sua ausência ou sua deterioração, por exemplo em casos de exsanguinação, embalsamento e carbonização. As drogas e seus metabólitos passam para o HV por difusão passiva e, de modo geral, a concentração dos analitos no HV é similar às concentrações obtidas no sangue. A cocaína e a benzoilecgonina são facilmente detectadas na matriz. Por outro lado, a difusão da morfina é bem limitada. O maior interesse do estudo de opioides é a análise de 6-acetilmorfina, que pode diferenciar o uso de heroína e morfina. O delta-9-tetrahidrocanabinol é uma molécula muito polar e fortemente ligada a proteínas plasmáticas, o que limita a sua difusão para o HV. Entre as anfetaminas, a metilenodioximetanfetamina e a metanfetamina são as moléculas mais estudadas no HV. Foi desenvolvido e validado um método utilizando GC-MS para análise simultânea de cocaína, anfetaminas, opioides, canabinoides e respectivos metabólitos em HV. Os analitos de interesse foram extraídos do HV utilizando extração em fase sólida e analisadas por GC-MS, utilizando o modo de aquisição SIM. A faixa de linearidade foi de 10 a 1000 ng/mL para todos os analitos, com exceção do éster de metilanidroecgonina (10 a 750 ng/mL). A exatidão variou de 95,6 a 104,0%, a precisão inter-ensaio variou de 1,2 a 10,0% e a precisão intra-ensaio foi menor que 10,4% para todos os analitos. O limite de quantificação para todas as drogas foi de 10 ng/mL e a recuperação variou de 70,4 a 100,1% para compostos básicos e neutros, entretanto os compostos ácidos apresentaram baixa recuperação - menor que 40%. A dosagem de etanol foi realizada por GC-FID e extração por headspace. Os métodos validados foram aplicados em 250 amostras de HV coletadas de vítimas de morte violentas nos anos de 2011 e 2012 que foram necropsiadas no Departamento Médico Legal de Vitória - ES. A maioria das vítimas era do sexo masculino (85,4%) e a causa mais comum de morte foi homicídio (46,2%), destes, 89,5% foram mortos por disparo de arma de fogo. Os acidentes de trânsito corresponderam a 44,1%; suicídio, 2,4%; e outras mortes totalizaram 7,2% das amostras. Substâncias psicoativas (álcool e drogas) foram positivas em 60,4% dos casos. Em 23,2% das amostras foi quantificada cocaína e/ou seu metabólito, e em um terço destes foi identificado o uso de crack. O álcool estava presente em 19,2% dos casos e a associação entre cocaína e álcool em 12,8% dos casos. Outras drogas incluíram anfetaminas (13 casos) e codeína (1 caso). Quando comparadas as concentrações das drogas pesquisadas no sangue e HV, a anfetamina e metanfetamina mostraram boa correlação entre as duas matrizes. A 6-acetilmorfina encontrada no HV foi utilizada para demonstrar o uso de heroína, uma vez que as concentrações foram mais altas do que no sangue. Entretanto, o HV não pode ser utilizado como amostra alternativa para detecção de canabinoides.Vitreous humor is the aqueous gel located between the lens and retina. Vitreous humor is a useful alternative postmortem matrix for the detection of drugs, particularly in death investigations where postmortem blood is not available or is of limited quality or quantity (e.g. after hemorrhagic shock, burns, embalming or decomposition processes). Drugs and their metabolites enter the vitreous humor by passive diffusion from blood across the blood-vitreous barrier. Vitreous humor concentrations are often similar to the drug concentrations in the circulation blood. Cocaine and benzoylecgonine are easily detected in this matrix. On the order hand, morphine diffusion is limited. The interest in opiates is due to 6-acetylmorphine, which is stable in vitreous humor and can confirm heroin abuse. Drugs that are highly protein-bound, such as THC, achieve lower vitreous humor concentrations as only the free fraction can cross the blood-vitreous barrier. Methamphetamine and methylenodioxymetamphetamine are also detected in vitreous humor. A GC-MS method for simultaneous analysis of cocaine, amphetamines, opiates, cannabinoids and its metabolites in vitreous humor was developed and fully validated. Vitreous humor samples were extracted using solid phase extraction and analyzed by GC-MS in SIM mode. For all analytes the linearity ranged from 10 to 1000 ng/mL, excepted for anydroecgonine methylester which ranged from 10 to 750 ng/mL. Inter-assay imprecision ranged from 1.2 to 10.0% and intra-assay imprecision was less than 10.4% for all analytes at all QC concentrations. Accuracy ranged from 95.6 to 104.0% and recoveries ranging from 70.4 - 100.1% for basic and neutral compounds, the acids compounds had poor recovery (less than 40%). The limits of detection were up to 1.0 ng/mL. Ethanol was quantified by headspace extraction and GC-FID. The validated methodology was applied to 250 vitreous humor samples collected from violent death victims between 2011 and 2012 in the Departamento Médico Legal de Vitória - ES. Most of the victims were male (85.4%) and the most common cause of death was homicide (46.2%), in which 89.5 occurred by firearm shot. Traffic accident represented 44.1%, suicide 2.4% and other deaths 7.2%. Psychoactive substances (alcohol and?or drugs of abuse) were positive in 60.4% of the cases. Cocaine was quantified in 23.2% of the samples and one third was positive for crack cocaine. Ethanol was present in 19.2% of the cases and the association between cocaine and alcohol in 12.8%. Other drugs included amphetamines (13 cases) and codeine (1 case). When comparing the drug concentrations in blood and vitreous humor, amphetamine and methamphetamine showed a good correlation. 6-acetylmorphine in vitreous humor can demonstrate heroine abuse and its concentration is higher in vitreous humor than in blood. However, vitreous humor is not a good matrix for the detection of cannabinoids.
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Tram, Nguyen Khoi. "Hydrogels with Antioxidants that Replace the Physical and Chemical Functions of the Vitreous Humor". The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu158558328501199.
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Santos, Júnior Júlio César 1985. "Novas técnicas analíticas aplicadas a drogas de abuso presentes em humor vítreo". [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/312948.
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Orientadores: Nelci Fenalti Höehr, Marcos Nogueira EberlinDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas
Made available in DSpace on 2018-08-26T10:40:41Z (GMT). No. of bitstreams: 1 SantosJunior_JulioCesar_M.pdf: 4092105 bytes, checksum: 8809a688f7411f1a87fd956c6674fe41 (MD5) Previous issue date: 2014
Resumo: Embora as anfetaminas estejam proibidas no Brasil, elas continuam sendo adquiridas ilegalmente assim como os canabinóides e cocaína, que representam um dos principais problemas de saúde pública a serem enfrentados no nosso país. Um dos grandes desafios desta área é a dificuldade de obtenção de material para exames periciais. O humor vítreo por encontrar-se isolado em um compartimento relativamente protegido de contaminação externa, invasão de microorganismos e traumatismos em geral, bem como por sua simplicidade/estabilidade analítica e esterilidade durante um longo período após a morte constitui-se como uma excelente amostra para a determinação de xenobióticos em corpos politraumatizados, carbonizados ou em decomposição, auxiliando na delegação da causa mortis. O uso da espectrometria de massas e o advento de novas metodologias de ionização são ferramentas essenciais à toxicologia forense, a V-EASI (venture easy ambient sonic-spray), é uma fonte de ionização de fácil aplicação e instalação, que não requer fluxo de eluente e os demais fatores utilizados nas fontes comerciais. Além disso, o uso da espectrometria de massas de ressonância ciclotrônica de íons por transformada de Fourier (FT-ICR-MS) de ultra-alta resolução e exatidão (valores de m/z exatos) leva a exata composição molecular, alcançando erros abaixo de 1 ppm (partes-por-milhão). Perante isso a avaliação da fórmula molecular normalmente é inequívoca. Quando acoplada a ionização por eletrospray (ESI) espécies moleculares suaves são formadas reduzindo a complexidade do espectro e produzindo informação composicional livre de fragmentos em misturas complexas facilitando sua compreensão. Portanto este trabalho visa o desenvolvimento de metodologias analíticas para análise de drogas de abuso presentes em humor vítreo, empregando o uso de técnicas modernas de espectrometria de massas (FT-ICR-MS e V-EASI-MS)
Abstract: Although amphetamines are banned in Brazil, they remain illegally acquired as cannabinoids and cocaine, which account for a public health task to be faced in this country. The major challenge is to obtain material for investigation exams. The vitreous humor constitutes a good alternative for these exams, since it occurs isolated in a protected space, free of external contamination and of microorganisms and traumatisms, and also due to its analytical stability and sterility preserving it for a long period after death. Moreover, the vitreous humor constitutes an excellent sample for the determination of xenobiotics even in polytraumatized bodies, carbonized or in decomposition, involved in the causa mortis. The use of mass spectrometry and the advent of new ionization methods are essential tools for forensic toxicology, the V-EASI (venture easy ambient sonic-spray), is a source of ionization easy to use and install, not requiring nitrogen flow, eluent flow and other factors used in commercial sources. Furthermore, the use of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) provides ultra high resolution and accuracy in mass analysis and its accurate m/z values lead to the exact molecular composition, reaching errors below 1 ppm (parts-per-million) on normal operational conditions, the assigned molecular formula are normally unequivocal. When electrospray ionization (ESI) is used, soft molecular species are formed reducing spectra complexity and providing fragment-free compositional information about complex mixtures facilitating comprehension. Therefore, this work aims at the development of analytical methodologies for the analysis of drugs of abuse present in the vitreous humor, employing the use of modern techniques of mass spectrometry (FT-ICR-MS and V-EASI-MS
Mestrado
Ciencias Biomedicas
Mestre em Ciências Médicas
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Ishikawa, Aline Akemi. "Desenvolvimento de metodologia analítica para a investigação de metilenodioxi derivados em amostras de humor vítreo em vítimas fatais de acidentes de trânsito". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/60/60134/tde-12122011-083238/.
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Os metilenodioxi derivados estão entre as drogas sintéticas de uso ilícito mais consumidas no ocidente, são substâncias que causam alterações motoras e psíquicas e tem causado grande ameaça a segurança no trânsito, pois estes efeitos afetam o desempenho dos condutores, podendo causar acidentes de trânsito. O humor vítreo é uma matriz biológica disponível apenas nas análises postmortem, e é de grande relevância para toxicologia forense. Constitui uma matriz simples, de fácil coleta e manuseio, boa estabilidade, muito indicada principalmente nos casos de corpos politraumatizados, parcialmente carbonizados ou em estado de decomposição. Isto porque o humor vítreo localiza-se em uma área anatomicamente isolada, relativamente protegida contra a contaminação externa e invasão de microorganismos. O objetivo do presente trabalho foi desenvolver e validar uma metodologia analítica para detectar e quantificar metilenodioxi derivados em amostras de humor vítreo em vítimas fatais de acidentes de trânsito. Para desenvolvimento do método foi utilizado 1 mL de humor vítreo, extração líquido-líquido com solvente acetato de etila, derivatização com anidrido heptafluorobutírico (HFBA) e detecção por cromatografia gasosa acoplada a espectrometria de massas (CG/MS). A metologia foi validada de acordo com os parâmetros preconizados pela ANVISA e demonstrou linearidade de 10 a 400 ng/mL. Os limites de detecção variaram entre 1 a 2,5 ng/mL, a exatidão variou entre 97,1% -103,7%, na precisão intra-ensaio foram obtidos valores entre 4,54%-9,14% e na precisão inter- ensaio, valores entre 6,92%-10,59%. A recuperação encontrada foi superior a 57,87%. A metologia validada foi aplicada em humor vítreo de vítimas fatais de acidentes de trânsito coletadas no Centro de Medicina Legal de Ribeirão Preto (CEMEL).The methylenedioxy derivatives are among synthetic drugs of illicit use most consumed in the occident, these are substances cause mental and motor disorders and has caused major threat to traffic safety, these effects affect the performance of drivers and may lead to traffic accidents. The vitreous humor is a biological matrix available in postmortem analysis, and has great relevance to forensic toxicology. It is a simple matrix, clean, easy collection and handling, good stability, highly recommended especially in cases of body injuries, partially carbonization or in a state of decomposition. This is because the vitreous humor is located in an anatomically isolated area, relatively protected from external contamination and invasion of microorganisms. The purpose of this study was to develop and validate an analytical methodology to detect and quantify methylenedioxy derivatives in samples of vitreous humor in fatal traffic accidents. To develop the method we used 1 mL of vitreous humor, liquid-liquid extraction with ethyl acetate solvent, derivatization heptafluorobutyric anhydride (HFBA) and detection by gas chromatography-mass spectrometry (GC/MS). The methodology was validated according to the parameters established by ANVISA and demonstrated linearity from 10 to 400 ng /mL. The limits of detection were between 1,0 ng/mL and 2,5 ng / mL. The accuracy had values between 97.1% -103.7%, the intra-assay precision was 4.54% -9.14% and inter assay precision between 6.92% -10.59%. The recovery was higher than 57.87%. The methodology validated was applied in vitreous humor of victims of fatal traffic accidents collected in the Centre of Forensic Medicine of Ribeirão Preto (CEMEL)
Libros sobre el tema "Humour Vitrous"
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A, Schulman Joel, ed. Vitreous substitutes. East Norwalk, Conn: Appleton & Lange, 1995.
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F, Spaide Richard, ed. Diseases of the retina and vitreous. Philadelphia: W.B. Saunders, 1999.
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Johnston, Robert L. Retina, vitreous, and choroid: Clinical procedures. Boston: Butterworth-Heinemann, 1995.
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Symposium on Retina and Vitreous (1992 New Orleans, La.). Retina and vitreous: Proceedings of the Symposium on Retina and Vitreous, New Orleans, LA, USA, March 12-15, 1992. Amsterdam: Kluger Publications, 1993.
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Arnd, Gandorfer, ed. Pharmacology and vitreoretinal surgery. Basel: Karger, 2009.
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Elton, Ben. Inconceivable. New York: Dell Publishing, 2000.
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Inconceivable. London ; New York: Bantam Press, 1999.
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Inconceivable. London: Black Swan, 2000.
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Schepens, Charles L., Clement L. Trempe y Masataka Takahashi. Atlas of Vitreous Biomicroscopy. Butterworth-Heinemann, 1999.
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Török, M. Estée, Fiona J. Cooke y Ed Moran. Ophthalmological infections. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199671328.003.0020.
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This chapter covers periorbital infections such as blepharitis, and infections of the lacrimal apparatus such as canaliculitis, dacryocystitis, dacryoadenitis, and Mikulicz syndrome. The chapter also covers orbital infections such as preseptal (periorbital) cellulitis, and orbital (post-septal) cellulitis. The chapter also includes conjunctivitis (the commonest ocular inflammation), keratitis (an inflammation of the cornea), uveitis (an inflammation of the uveal tract), and endophthalmitis (an inflammation of the ocular cavity, i.e. aqueous and vitreous humour).
Capítulos de libros sobre el tema "Humour Vitrous"
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Stepien, Kimberly E. "Vitreous Humor". En Encyclopedia of Ophthalmology, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2012. http://dx.doi.org/10.1007/978-3-642-35951-4_140-2.
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Stepien, Kimberly E. "Vitreous Humor". En Encyclopedia of Ophthalmology, 1910–11. Berlin, Heidelberg: Springer Berlin Heidelberg, 2018. http://dx.doi.org/10.1007/978-3-540-69000-9_140.
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Chirila, T. V. y Y. Hong. "The Vitreous Humor". En Handbook of Biomaterial Properties, 125–31. Boston, MA: Springer US, 1998. http://dx.doi.org/10.1007/978-1-4615-5801-9_12.
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Chirila, Traian V. y Ye Hong. "Chapter C2 The Vitreous Humor". En Handbook of Biomaterial Properties, 125–34. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4939-3305-1_12.
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Repetto, Rodolfo y Mariia Dvoriashyna. "Mathematical Models of Vitreous Humour Dynamics and Retinal Detachment". En Ocular Fluid Dynamics, 303–25. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-25886-3_13.
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Madea, Burkhard. "“Normal” Values in Vitreous Humor — Reflections and Refutations". En Acta Medicinæ Legalis Vol. XLIV 1994, 421–24. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-642-79523-7_134.
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Coe, John I. "Post-mortem biochemistry of blood and vitreous humour in paediatric practice". En Paediatric Forensic Medicine and Pathology, 191–203. Boston, MA: Springer US, 1989. http://dx.doi.org/10.1007/978-1-4899-7160-9_13.
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Friedrich, Stuart, Bradley Saville y Yu-Ling Cheng. "Mathematical Modeling of Drug Distribution in the Vitreous Humor". En Ophthalmic Drug Delivery Systems, 181–221. 2a ed. London: Routledge, 2021. http://dx.doi.org/10.4324/9781003113423-8.
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Clayton, E. H., Q. Wang, S. K. Song, R. J. Okamoto y P. V. Bayly. "Magnetic Resonance Elastography of the Mouse Vitreous Humor In Vivo". En Application of Imaging Techniques to Mechanics of Materials and Structures, Volume 4, 129–33. New York, NY: Springer New York, 2012. http://dx.doi.org/10.1007/978-1-4419-9796-8_16.
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Kintz, P., A. Tracqui y P. Mangin. "Toxicological Investigations on Unusual Materials (Hair and Vitreous Humor): Interest and Limitations". En Archives of Toxicology, 282–85. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-77260-3_37.
Texto completoActas de conferencias sobre el tema "Humour Vitrous"
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Kummer, Michael P., Jake J. Abbott, Sandro Dinser y Bradley J. Nelson. "Artificial Vitreous Humor for In Vitro Experiments". En 2007 29th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 2007. http://dx.doi.org/10.1109/iembs.2007.4353822.
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Bonfiglio, Andrea, Alessandro Stocchino, Rodolfo Repetto y Jennifer H. Siggers. "In-Vitro Simulations of Drug Delivery in the Vitreous Chamber of the Eye". En ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80272.
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The vitreous chamber has an approximately spherical shape, and is filled with vitreous humor, a transparent material with viscoelastic properties. The vitreous humor has the mechanical roles of supporting the eye shape, promoting the adherence between the retina and the choroid, and acting as a barrier between the anterior and posterior segments of the eye for transport of heat and molecules [1]. Often, in elderly people, the vitreous humor has almost Newtonian properties as a consequence of a liquefaction process consisting of degradation of the collagenous framework of the gel. Moreover, after vitrectomy the vitreous humor is sometimes replaced with viscous tamponade fluids (typically silicone oils). Since intra-vitreal drug injection is increasingly used to treat retinal diseases, and the efficacy of this procedure depends on molecular transport processes after the injection, much of the biomechanical research on the vitreous humor has focused on understanding transport processes in the vitreous chamber. Many authors have considered purely diffusive transport or alternatively diffusion with advective transport due to creeping bulk flow only [2,3]. However, when the vitreous is liquefied, rotational motion of the eye has been shown to induce significant fluid flow, which plays a fundamental role for drug delivery in the vitreous chamber [4–7]. The most significant contribution to mass transport is due to the generation of a steady streaming flow, i.e. a steady flow resulting from the non-linearity in the equations. This flow component gives rise to a slow particle drift that becomes dominant over long times.
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Silue, Tjerignimin, Saugandhika Minnikanti y Nathalia Peixoto. "Randles Model of Vitreous Humor". En 10th International Conference on Biomedical Electronics and Devices. SCITEPRESS - Science and Technology Publications, 2017. http://dx.doi.org/10.5220/0006166001560162.
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Meskauskas, Julia, Rodolfo Repetto y Jennifer H. Siggers. "Theoretical Model of the Dynamic Stress on the Retina During Eye Rotations". En ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80526.
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The vitreous humor is the transparent gel-like material that fills the vitreous chamber, the largest chamber of the eye, which has an approximately spherical shape. The viscoelastic properties of the vitreous humor have been studied by several authors [1–3].
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Stocchino, Alessandro, Rodolfo Repetto y Jennifer H. Siggers. "Steady Streaming in the Liquefied Vitreous Due to Saccadic Eye Movements". En ASME 2009 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2009. http://dx.doi.org/10.1115/sbc2009-206191.
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The posterior chamber of the eye has an approximately spherical shape, and is filled with vitreous humor, a transparent material with viscoelastic properties [1]. The vitreous has the mechanical roles of supporting the eye shape, promoting the adherence between the retina and the choroid, and acting as a barrier between the anterior and posterior segments of the eye that inhibits both heat diffusion and molecular transport [2]. Sometimes, particularly in elderly people, the fluid in the posterior chamber has almost Newtonian properties. This can be as a consequence of liquefaction of the vitreous humor due to synchisys (degradation of the collagenous framework of the vitreous humor), or after a vitrectomy, a surgical procedure in which the vitreous humor is replaced by tamponade fluids (typically silicone oils). Since intra-vitreal drug injection is increasingly used to treat retinal diseases, and the efficacy of this procedure depends on molecular transport processes following injection, much of the biomechanical research on the vitreous humor has focused on understanding these processes. Many authors have considered purely diffusive transport or alternatively purely advective transport due to creeping bulk flow [3,4]. However, when the vitreous is liquefied, rotational motion of the eye is also likely to induce significant fluid flow.
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Rendon-Nava, A., L. Nino-de-Rivera-y-O, V. Ponomaryov, M. Cuz Irisson y R. Vazquez M. "Intraocular pressure system inside vitreous humor". En 2008 International Conference on Mathematical Methods in Electromagnetic Theory (MEET). IEEE, 2008. http://dx.doi.org/10.1109/mmet.2008.4581013.
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Cafferata, Chiara, Rodolfo Repetto, Jennifer Siggers y Alessandro Stocchino. "Fluid Dynamic Events Within the Vitreous Cavity Induced by Saccadic Eye Rotations". En ASME 2007 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2007. http://dx.doi.org/10.1115/sbc2007-176417.
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The vitreous cavity constitutes most of the eye volume and is filled by the vitreous humour or vitreous body. It has the shape of a weakly deformed sphere, the deformation being essentially due to the presence of the lens, which produces an inward indentation in the anterior part of the chamber. Under normal conditions the vitreous body has the consistency of a gel with viscoelastic rheological behaviour [1]. Ageing gradually disintegrates the gel structure leading to a partial or total vitreous liquefaction. After some surgical procedures (vitrectomy) the vitreous body may be completely replaced by “tamponade fluids”, typically silicon oils, which are left for a certain time within the eye and are eventually replaced by water.
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Amini, Rouzbeh, Victor H. Barocas, H. Pirouz Kavehpour y Jean Pierre Hubschman. "Intraocular Pressure Alters Following Altitude Changes in Patients With Gas-Filled Eyes: Theoretical Analysis". En ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19150.
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Retinal detachment is an eye disorder that, if not treated, can lead to blindness. One of the treatment options is removing all or part of vitreous humor from the vitreous cavity and filling it with a gas bubble. The gas bubble eventually reabsorbs over a few weeks into the systemic circulation.
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Urbanska, Magdalena Anna, Sophia Areta Rodrigues y Frédérique Vanholsbeeck. "Validation of optical coherence elastography to study frequency dependent behaviour of the vitreous humour". En Optical Elastography and Tissue Biomechanics VIII, editado por Kirill V. Larin y Giuliano Scarcelli. SPIE, 2021. http://dx.doi.org/10.1117/12.2577967.
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Biswas, Satarupa, Debanjan Das, Manjunatha Mahadevappa y Soumen Das. "Characterization of retinal tissue and vitreous humor with Electrical Impedance Spectroscopy". En 2017 8th International IEEE/EMBS Conference on Neural Engineering (NER). IEEE, 2017. http://dx.doi.org/10.1109/ner.2017.8008323.
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