Academic literature on the topic 'Amb a 1'
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Journal articles on the topic "Amb a 1"
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Ogoshi, Maho, Shigenori Nobata, and Yoshio Takei. "Potent osmoregulatory actions of homologous adrenomedullins administered peripherally and centrally in eels." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 295, no. 6 (December 2008): R2075—R2083. http://dx.doi.org/10.1152/ajpregu.90688.2008.
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The teleost adrenomedullin (AM) family consists of three groups, AM1/AM4, AM2/AM3, and AM5. In the present study, we examined the effects of homologous AM1, AM2, and AM5 on drinking and renal function after peripheral or central administration in conscious freshwater eels. AM2 and AM5, but not AM1, exhibited dose-dependent (0.01–1 nmol/kg) dipsogenic and antidiuretic effects after intra-arterial bolus injection. The antidiuretic effect was significantly correlated with the degree of associated hypotension. To avoid the potential indirect osmoregulatory effects of AM-induced hypotension, infusion of AMs was also performed at nondepressor doses. Drinking was enhanced dose-dependently at 0.1–3 pmol·kg−1·min−1 of AM2 and AM5, matching the potency and efficacy of angiotensin II (ANG II), the most potent dipsogenic hormone known thus far. AM2 and AM5 infusion also induced mild antidiuresis, while AM1 caused antinatriuresis. Additionally, AMs were injected into the third and fourth ventricles of conscious eels to assess their site of dipsogenic action. However, none of the AMs at 0.05–0.5 nmol induced drinking, while ANG II was highly dipsogenic. AM2 and ANG II injected into the third ventricle increased arterial pressure while AM5 decreased it in a dose-dependent manner, and both AM2 and AM5 decreased blood pressure when injected into the fourth ventricle. These data suggest that circulating AM2 and AM5 act on a target site in the brain that lacks the blood-brain barrier. Collectively, the present study showed that AM2 and AM5 are potent osmoregulatory hormones in the eel, and their actions imply involvement in seawater adaptation of this euryhaline species.
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Oakley, Karen L., Caroline B. Moore, and David W. Denning. "In Vitro Activity of the Echinocandin Antifungal Agent LY303,366 in Comparison with Itraconazole and Amphotericin B against Aspergillus spp." Antimicrobial Agents and Chemotherapy 42, no. 10 (October 1, 1998): 2726–30. http://dx.doi.org/10.1128/aac.42.10.2726.
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ABSTRACT LY303,366 (LY) is a novel derivative of the echinocandin class of antifungal agents. The in vitro activities of LY, itraconazole (ITZ), and amphotericin B (AMB) were assessed against 60Aspergillus isolates, including 35 isolates of A. fumigatus, eight isolates of A. terreus, eight isolates of A. flavus, eight isolates of A. niger and one isolate of A. nidulans. Four A. fumigatus isolates were resistant to ITZ. Susceptibility testing for all drugs was performed with a broth microdilution procedure. LY was tested in two media: antibiotic medium 3 (AM3) and Casitone with 2% glucose (CAS) with an inoculum of 2 × 103spores/ml. ITZ and AMB were tested in RPMI 1640 with 2% glucose with an inoculum of 1 × 106 spores/ml. All tests were incubated at 37°C for 48 h. A novel end point was used to determine a minimal effective concentration (MEC) for LY, i.e., almost complete inhibition of growth save a few tiny spherical colonies attached to the microplate. MICs were measured for ITZ and AMB with a no-growth end point. Ranges and geometric mean (GM) MECs were from 0.0018 to >0.5 and 0.0039 mg/liter and from 0.0018 to >0.5 and 0.008 mg/liter for LY in AM3 and LY in CAS, respectively. Differences between species were apparent, with A. flavus being significantly less susceptible to LY than any other species tested with both media (P ≤ 0.05). Ranges and GM MICs were from 0.125 to >16 and 0.7 mg/liter for ITZ and from 0.25 to 16 and 1.78 mg/liter for AMB. Minimal fungicidal concentrations (MFCs) were also determined for all drugs. GM MFCs were 0.018, 0.09, 19.76, and 12.64 mg/liter for LY in AM3, LY in CAS, ITZ, and AMB, respectively. LY in AM3 and LY in CAS were fungicidal for 86.7 and 68% of isolates, respectively (98% killing). In comparison, ITZ and AMB were fungicidal for 35 and 70% of isolates, respectively (99.99% killing). A reproducibility study was performed on 20% of the isolates. For 12 isolates retested, the MEC or MIC was the same or was within 1 dilution of the original value for 11, 11, 10, and 9 isolates for LY in AM3, LY in CAS, ITZ, and AMB, respectively. In conclusion, LY seems to be a promising antifungal agent with excellent in vitro activity against Aspergillusspp.
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Yeo, Eun-Jin, Ji-Hye Ryu, Young-Suk Cho, Yang-Sook Chun, L. Eric Huang, Myung-Suk Kim, and Jong-Wan Park. "Amphotericin B blunts erythropoietin response to hypoxia by reinforcing FIH-mediated repression of HIF-1." Blood 107, no. 3 (February 1, 2006): 916–23. http://dx.doi.org/10.1182/blood-2005-06-2564.
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AbstractAmphotericin B (AmB) is widely used for treating severe systemic fungal infections. However, long-term AmB treatment is invariably associated with adverse effects such as anemia. The erythropoietin (EPO) suppression by AmB has been proposed to contribute to the development of anemia. However, the mechanism whereby EPO is suppressed remains obscure. In this study, we investigated the possibility that AmB inhibits the transcription of the EPO gene by inactivating HIF-1, which is a known key transcription factor and regulator of EPO expression. EPO mRNA levels were markedly attenuated by AmB treatment both in rat kidneys and in Hep3B cells. AmB inactivated the transcriptional activity of HIF-1α, but did not affect the expression or localization of HIF-1 subunits. Moreover, AmB was found to specifically repress the C-terminal transactivation domain (CAD) of HIF-1α, and this repression by AmB required Asn803, a target site of the factor-inhibiting HIF-1 (FIH); moreover, this repressive effect was reversed by FIH inhibitors. Furthermore, AmB stimulated CAD-FIH interaction and inhibited the p300 recruitment by CAD. We propose that this mechanism underlies the unexplained anemia associated with AmB therapy.
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Montagna, Maria Teresa, Grazia Lovero, Caterina Coretti, Osvalda De Giglio, Domenico Martinelli, Andrea Bedini, Mario Delia, Antonio Rosato, Mauro Codeluppi, and Giuseppina Caggiano. "In vitro activities of amphotericin B deoxycholate and liposomal amphotericin B against 604 clinical yeast isolates." Journal of Medical Microbiology 63, no. 12 (December 1, 2014): 1638–43. http://dx.doi.org/10.1099/jmm.0.075507-0.
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We determined the in vitro antifungal activity of liposomal amphotericin B (L-AmB) against 604 clinical yeast isolates. Amphotericin B deoxycholate (D-AmB) was tested in parallel against all the isolates. Susceptibility testing was performed according to the Clinical and Laboratory Standards Institute (CLSI) M27-A3 method. Overall, L-AmB was highly active against the isolates (mean MIC, 0.42 µg ml−1; MIC90, 1 µg ml−1; 97.2 % of MICs were ≤1 µg ml−1) and comparable to D-AmB (mean MIC, 0.48 µg ml−1; MIC90, 1 µg ml−1; 97.3 % of MICs were ≤1 µg ml−1). The in vitro activity of D-AmB and L-AmB was correlated (R 2 = 0.61; exp(b), 2.3; 95 % CI, 2.19–2.44, P<0.001). Candida albicans (mean MICs of D-AmB and L-AmB, 0.39 µg ml−1 and 0.31 µg ml−1, respectively) and Candida parapsilosis (mean MICs of D-AmB and L-AmB, 0.38 µg ml−1 and 0.35 µg ml−1, respectively) were the species most susceptible to the agents tested, while Candida krusei (currently named Issatchenkia orientalis) (mean MICs of D-AmB and L-AmB, 1.27 µg ml−1 and 1.13 µg ml−1, respectively) was the least susceptible. The excellent in vitro activity of L-AmB may have important implications for empirical treatment approaches and support its role in treatment of a wide range of invasive infections due to yeasts.
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Zbîrcea, Lauriana-Eunice, Maria-Roxana Buzan, Manuela Grijincu, Elijahu Babaev, Frank Stolz, Rudolf Valenta, Virgil Păunescu, Carmen Panaitescu, and Kuan-Wei Chen. "Relationship between IgE Levels Specific for Ragweed Pollen Extract, Amb a 1 and Cross-Reactive Allergen Molecules." International Journal of Molecular Sciences 24, no. 4 (February 17, 2023): 4040. http://dx.doi.org/10.3390/ijms24044040.
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Ragweed (Ambrosia artemisiifolia) pollen is a major endemic allergen source responsible for severe allergic manifestations in IgE-sensitized allergic patients. It contains the major allergen Amb a 1 and cross-reactive allergen molecules, such as the cytoskeletal protein profilin, Amb a 8 and calcium-binding allergens Amb a 9 and Amb a 10. To assess the importance of Amb a 1, profilin and calcium-binding allergen, the IgE reactivity profiles of clinically well-characterized 150 ragweed pollen-allergic patients were analysed regarding specific IgE levels for Amb a 1 and cross-reactive allergen molecules by quantitative ImmunoCAP measurements, IgE ELISA and by basophil activation experiments. By quantifying allergen-specific IgE levels we found that Amb a 1-specific IgE levels accounted for more than 50% of ragweed pollen-specific IgE in the majority of ragweed pollen-allergic patients. However, approximately 20% of patients were sensitized to profilin and the calcium-binding allergens, Amb a 9 and Amb a 10, respectively. As shown by IgE inhibition experiments, Amb a 8 showed extensive cross-reactivity with profilins from birch (Bet v 2), timothy grass (Phl p 12) and mugwort pollen (Art v 4) and was identified as a highly allergenic molecule by basophil activation testing. Our study indicates that molecular diagnosis performed by the quantification of specific IgE to Amb a 1, Amb a 8, Amb a 9 and Amb a 10 is useful to diagnose genuine sensitization to ragweed pollen and to identify patients who are sensitized to highly cross-reactive allergen molecules present in pollen from unrelated plants, in order to enable precision medicine-based approaches for the treatment and prevention of pollen allergy in areas with complex pollen sensitization.
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Lobato-Freitas, Carolina, Andreia Machado Brito-da-Costa, Ricardo Jorge Dinis-Oliveira, Helena Carmo, Félix Carvalho, João Pedro Silva, and Diana Dias-da-Silva. "Overview of Synthetic Cannabinoids ADB-FUBINACA and AMB-FUBINACA: Clinical, Analytical, and Forensic Implications." Pharmaceuticals 14, no. 3 (February 25, 2021): 186. http://dx.doi.org/10.3390/ph14030186.
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ADB-FUBINACA and AMB-FUBINACA are two synthetic indazole-derived cannabinoid receptor agonists, up to 140- and 85-fold more potent, respectively, than trans-∆9-tetrahydrocannabinol (∆9-THC), the main psychoactive compound of cannabis. Synthesised in 2009 as a pharmaceutical drug candidate, the recreational use of ADB-FUBINACA was first reported in 2013 in Japan, with fatal cases being described in 2015. ADB-FUBINACA is one of the most apprehended and consumed synthetic cannabinoid (SC), following AMB-FUBINACA, which emerged in 2014 as a drug of abuse and has since been responsible for several intoxication and death outbreaks. Here, we critically review the physicochemical properties, detection methods, prevalence, biological effects, pharmacodynamics and pharmacokinetics of both drugs. When smoked, these SCs produce almost immediate effects (about 10 to 15 s after use) that last up to 60 min. They are rapidly and extensively metabolised, being the O-demethylated metabolite of AMB-FUBINACA, 2-(1-(4-fluorobenzyl)-1H-indazole-3-carboxamide)-3-methylbutanoic acid, the main excreted in urine, while for ADB-FUBINACA the main biomarkers are the hydroxdimethylpropyl ADB-FUBINACA, hydroxydehydrodimethylpropyl ADB-FUBINACA and hydroxylindazole ADB-FUBINACA. ADB-FUBINACA and AMB-FUBINACA display full agonism of the CB1 receptor, this being responsible for their cardiovascular and neurological effects (e.g., altered perception, agitation, anxiety, paranoia, hallucinations, loss of consciousness and memory, chest pain, hypertension, tachycardia, seizures). This review highlights the urgent requirement for additional studies on the toxicokinetic properties of AMB-FUBINACA and ADB-FUBINACA, as this is imperative to improve the methods for detecting and quantifying these drugs and to determine the best exposure markers in the various biological matrices. Furthermore, it stresses the need for clinicians and pathologists involved in the management of these intoxications to describe their findings in the scientific literature, thus assisting in the risk assessment and treatment of the harmful effects of these drugs in future medical and forensic investigations.
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Chen, Tao, Lawrence Mwenge, Shabir Lakhi, Duncan Chanda, Peter Mwaba, Síle F. Molloy, Adrian Gheorghe, et al. "Healthcare Costs and Life-years Gained From Treatments Within the Advancing Cryptococcal Meningitis Treatment for Africa (ACTA) Trial on Cryptococcal Meningitis: A Comparison of Antifungal Induction Strategies in Sub-Saharan Africa." Clinical Infectious Diseases 69, no. 4 (March 13, 2019): 588–95. http://dx.doi.org/10.1093/cid/ciy971.
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Abstract Background Mortality from cryptoccocal meningitis remains high. The ACTA trial demonstrated that, compared with 2 weeks of amphotericin B (AmB) plus flucystosine (5FC), 1 week of AmB and 5FC was associated with lower mortality and 2 weeks of oral flucanozole (FLU) plus 5FC was non-inferior. Here, we assess the cost-effectiveness of these different treatment courses. Methods Participants were randomized in a ratio of 2:1:1:1:1 to 2 weeks of oral 5FC and FLU, 1 week of AmB and FLU, 1 week of AmB and 5FC, 2 weeks of AmB and FLU, or 2 weeks of AmB and 5FC in Malawi, Zambia, Cameroon, and Tanzania. Data on individual resource use and health outcomes were collected. Cost-effectiveness was measured as incremental costs per life-year saved, and non-parametric bootstrapping was done. Results Total costs per patient were US $1442 for 2 weeks of oral FLU and 5FC, $1763 for 1 week of AmB and FLU, $1861 for 1 week of AmB and 5FC, $2125 for 2 weeks of AmB and FLU, and $2285 for 2 weeks of AmB and 5FC. Compared to 2 weeks of AmB and 5FC, 1 week of AmB and 5FC was less costly and more effective and 2 weeks of oral FLU and 5FC was less costly and as effective. The incremental cost-effectiveness ratio for 1 week of AmB and 5FC versus oral FLU and 5FC was US $208 (95% confidence interval $91–1210) per life-year saved. Clinical Trials Registration ISRCTN45035509. Conclusions Both 1 week of AmB and 5FC and 2 weeks of Oral FLU and 5FC are cost-effective treatments.
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Nath, Christa E., Peter J. Shaw, Robyn Gunning, Andrew J. McLachlan, and John W. Earl. "Amphotericin B in Children with Malignant Disease: a Comparison of the Toxicities and Pharmacokinetics of Amphotericin B Administered in Dextrose versus Lipid Emulsion." Antimicrobial Agents and Chemotherapy 43, no. 6 (June 1, 1999): 1417–23. http://dx.doi.org/10.1128/aac.43.6.1417.
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ABSTRACT In a prospective, randomized clinical trial, the toxicity of 1 mg of amphotericin B (AmB) per kg of body weight per day infused in 5% dextrose was compared with that of AmB infused in lipid emulsion in children with malignant disease. In an analysis of 82 children who received a full course of 6 days or more of AmB (117 courses), it was shown that there were significant increases in plasma urea and creatinine concentrations and in potassium requirement after 6 days of therapy with both AmB infused in dextrose and AmB infused in lipid emulsion, with there being no difference between the two methods of AmB administration. An intent-to-treat comparison of the numbers of courses affected by acute toxicity (fever, rigors) and chronic toxicity (nephrotoxicity) also indicated that there was no significant difference between AmB infused in dextrose (78 courses) and AmB infused in lipid emulsion (84 courses). The pharmacokinetics of AmB were investigated in 20 children who received AmB in dextrose and 15 children who received AmB in lipid emulsion. Blood samples were collected up to 24 h after administration of the first dose, and the concentration of AmB in plasma was analyzed by a high-performance liquid chromatography assay. The clearance (CL) of AmB in dextrose (0.039 ± 0.016 liter · h−1 · kg−1) was significantly lower (P < 0.005) than the CL of AmB in lipid emulsion (0.062 ± 0.024 liter · h−1 · kg−1). The steady-state volume of distribution for AmB in dextrose (0.83 ± 0.33 liter · kg−1) was also significantly lower (P < 0.005) than that for AmB in lipid emulsion (1.47 ± 0.77 liter · kg−1). Although AmB in lipid emulsion is apparently cleared faster and distributes more widely than AmB in dextrose, this study did not reveal any significant advantage with respect to safety and tolerance in the administration of AmB in lipid emulsion compared to its administration in dextrose in children with malignant disease.
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Alakkad, Abdulghani, Paul Stapleton, Corinna Schlosser, Sudaxshina Murdan, Uchechukwu Odunze, Andreas Schatzlein, and Ijeoma F. Uchegbu. "Amphotericin B Polymer Nanoparticles Show Efficacy against Candida Species Biofilms." Pathogens 11, no. 1 (January 7, 2022): 73. http://dx.doi.org/10.3390/pathogens11010073.
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Purpose: Chronic infections of Candida albicans are characterised by the embedding of budding and entwined filamentous fungal cells into biofilms. The biofilms are refractory to many drugs and Candida biofilms are associated with ocular fungal infections. The objective was to test the activity of nanoparticulate amphotericin B (AmB) against Candida biofilms. Methods: AmB was encapsulated in the Molecular Envelope Technology (MET, N-palmitoyl-N-monomethyl-N,N-dimethyl-N,N,N-trimethyl-6-O-glycolchitosan) nanoparticles and tested against Candida biofilms in vitro. Confocal laser scanning microscopy (CLSM) imaging of MET nanoparticles’ penetration into experimental biofilms was carried out and a MET-AmB eye drop formulation was tested for its stability. Results: MET-AmB formulations demonstrated superior activity towards C. albicans biofilms in vitro with the EC50 being ~30 times lower than AmB alone (EC50 MET-AmB = 1.176 μg mL−1, EC50 AmB alone = 29.09 μg mL−1). A similar superior activity was found for Candida glabrata biofilms, where the EC50 was ~10× lower than AmB alone (EC50 MET-AmB = 0.0253 μg mL−1, EC50 AmB alone = 0.289 μg mL−1). CLSM imaging revealed that MET nanoparticles penetrated through the C. albicans biofilm matrix and bound to fungal cells. The activity of MET-AmB was no different from the activity of AmB alone against C. albicans cells in suspension (MET-AmB MIC90 = 0.125 μg mL−1, AmB alone MIC90 = 0.250 μg mL−1). MET-AmB eye drops were stable at room temperature for at least 28 days. Conclusions: These biofilm activity findings raise the possibility that MET-loaded nanoparticles may be used to tackle Candida biofilm infections, such as refractory ocular fungal infections.
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Florenza Satorres, Patrícia. "Actors, mims i altres pallassades. 3, 2, 1, acció!" Comunicació educativa, no. 30 (March 24, 2020): 61. http://dx.doi.org/10.17345/comeduc201761-76.
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Des de fa uns anys, a l’Escola Guillem Fortuny de Cambrils duem a terme una experiència expressiva, vivencial i creativa en què, mitjançant l’experimentació dels diferents recursos expressius i el treball del llenguatge corporal, els alumnes fan representacions amb mímica en grups cooperatius.L’expressió corporal potencia el desenvolupament natural de les expressions i manifestacions corporals de l’infant, amb la idea que sigui ell mateix i que el joc amb el cos li serveixi per conèixer-se i aprendre a comunicar-se sense contradiccions que l’inhibeixin.
Dissertations / Theses on the topic "Amb a 1"
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Borrisser, Pairó Francesc. "Expressió miocardíaca d'IGF-1 i miostatina en donants hipertensos i amb consum excessiu d'alcohol. Relació amb el desenvolupament de miocardiopatia." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/668698.
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Les miocardiopaties són malalties cardíaques d’etiologia molt diversa, entre les quals hi trobem la miocardiopatia hipertensiva i la miocardiopatia alcohòlica. La hipertensió arterial és una de les principals causes d’insuficiència cardíaca crònica. El consum crònic d’alcohol té efectes negatius sobre l’organisme: fetge, aparell digestiu, sistema neurològic i sistema cardiovascular. El dany cardíac causat per aquests factors (hipertensió i consum d’alcohol) està regulat per factors de creixement com l’insuline-like growth factor-1 (IGF-1) i la miostatina. En cas de dany miocardíac, el cor té mecanismes compensatoris per tal de revertir-lo. En aquesta tesi s’analitzaran els efectes de la hipertensió arterial i el consum crònic d’alcohol sobre l’expressió miocardíaca d’IGF-1 i miostatina. Per a l’execució d’aquesta tesi, es disposava de teixit cardíac de donants dividits en diferents grups (sans, amb hipertensió, amb consum crònic d’alcohol i amb altres causes de miocardiopatia). Es va estudiar l’expressió miocardíaca d’IGF-1 i de miostatina mitjançant immunohistoquímica per a cada grup de donants. El consum excessiu d’alcohol en pacients que no presenten dany miocardíac disminueix l’expressió d’IGF-1. Els donants afectats de miocardiopatia (hipertensiva o alcohòlica) presenten un augment en l’expressió de miostatina. Aquests resultats obren la porta a un objectiu terapèutic amb IGF-1 i miostatina per tal de controlar el dany cardíac causat per la hipertensió o el consum d’alcohol.Cardiomyopathies are cardiac diseases of various causes, among them hypertensive cardiomyopathy and alcoholic cardiomyopathy. Arterial hypertension is one of the main causes of cardiac failure. Chronic alcohol consumption has negative effects in the body: liver, digestive system, neurological system and cardiac system. The cardiac damage caused by these factors (hypertension and alcohol consumption) is regulated by growth factors such as insuline-like growth factor-1 (IGF-1) and myostatin. In case of cardiac damage, the heart has some compensatory mechanisms to revert them. In this thesis the effects of arterial hypertension and chronic alcohol consumption on IGF-1 and myostatin cardiac expression. Cardiac tissue from donors was available (healthy, with hypertension, with alcohol consumption and with other causes of cardiomyopathy). Excessive alcohol consumption in patients without cardiac damage decreases IGF-1 expression. Myocardiac expression of IGF-1 and myostatin was studied for each group of donors. Donors affected by cardiomyopathy (hypertensive or alcoholic) presented an increase on myostatin expression. These results open the door to a therapeutic objective with IGF-1 and myostatin to control the cardiac damage caused by hypertension or alcohol consumption.
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Serra, Planas Enric. "Prevalença de malaltia cardiovascular subclínica i associació amb factors de risc cardiovasculars no clàssics en el pacient amb diabetis mellitus tipus 1." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/666933.
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El maneig i el seguiment dels factors de risc cardiovascular clàssics com la hipertensió arterial, la hipercolesterolèmia, la hiperglucèmia i el tabaquisme no han aconseguit modificar la causa principal de morbimortalitat dels pacients amb diabetis mellitus del tipus 1, la malaltia arterial coronària. La importància d’aquesta complicació de la diabetis contrasta amb la controvèrsia que existeix sobre la necessitat d'un cribratge cardiovascular entre els pacients amb diabetis i malaltia cardiovascular subclínica, les diferents opinions sobre les proves d'imatge per a la diagnosi de la malaltia cardiovascular en fase preclínica i el poc coneixement del paper, en els pacients amb diabetis mellitus del tipus 1, de determinats factors de risc cardiovasculars de nova aparició com són la vitamina D, diversos marcadors inflamatoris o la malaltia hepàtica per dipòsit de greix no alcohòlica.
En aquesta investigació s’ha aprofundit en l’estudi meticulós d’una cohort de malalts de l'àrea Mediterrània de Badalona afectes de diabetis mellitus del tipus 1, asimptomàtics des del punt de vista cardiovascular i amb més de 10 anys d’evolució de la seva malaltia, mitjançant la caracterització clínica, l'anàlisi de paràmetres sèrics de potencial rellevància com l’adiponectina, l'YKL-40, la 25-hidroxivitamina D, així com l'avaluació ecogràfica hepàtica per a la detecció d'esteatosi hepàtica no alcohòlica. Tota la informació que se n’ha extret s’ha correlacionat amb dades d'ateroesclerosi precoç obtingudes mitjançant la mesura de la calcificació arterial coronària per tomografia computeritzada i la mesura del gruix de la capa íntima-mitja arterial carotídia mitjançant l’ecografia.
Com a resultats s’ha constatat que la nostra cohort, mostra significativa de la població amb diabetis mellitus del tipus 1 de la nostra àrea, presenta una molt reduïda prevalença de malaltia cardiovascular subclínica, aproximadament del 10%. A part, s’ha detecta una bona correlació entre els resultats de l'ecografia carotídia i la quantificació del calci coronari mitjançant la tomografia, fet que assenyala el potencial d’aquestes proves pel diagnòstic de la malaltia cardiovascular subclínica en els pacients amb diabetis mellitus del tipus 1. L’avaluació dels factors de risc cardiovasculars no clàssics quant a l’associació amb la presència de malaltia cardiovascular preclínica ha descartat les concentracions de vitamina D i els marcadors sèrics com l'adiponectina o l'YKL-40 però, per contra, en l'estudi univariant de la vinculació entre la presència d’esteatosi hepàtica la l’ateroesclerosi carotídia, es va confirmar una vinculació.
Es conclou que, en el nostre territori de reconegut baix risc cardiovascular, existeix una molt reduïda prevalença de malaltia cardiovascular subclínica entre els pacients amb diabetis mellitus del tipus 1, que no en justifica el cribratge generalitzat però que, en pacients determinats, disposem de proves diagnòstiques per a la seva detecció. Per tant, en l’estudi del pacient amb diabetis mellitus del tipus 1 de l'àrea Mediterrània i, basant-nos en les dades obtingudes, ens podem valdre de l'ecografia carotídia per a la detecció i de l'ecografia abdominal per a l’estratificació del risc cardiovascular. Aquest coneixement més profund de l’ateroesclerosi del pacient amb diabetis mellitus del tipus 1 de la nostra àrea, quant a prevalença com a mètodes de diagnosi, gravetat i factors associats, ens ajuda a dissenyar intervencions preventives, terapèutiques i de seguiment potencialment més dirigides i eficaces.The management and monitoring of classical cardiovascular risk factors such as hypertension, hypercholesterolemia, hyperglycaemia and smoking habit have not been able to modify the main cause of morbidity and mortality in patients with type 1 diabetes mellitus, the coronary artery disease. The importance of this diabetes complication contrasts with the existing controversy about the need for cardiovascular screening among patients with diabetes and subclinical cardiovascular disease, with different opinions about some image tests for the diagnosis of the cardiovascular disease in the preclinical phase and with the lack of knowledge about the real role, in patients with type 1 diabetes mellitus, of certain new cardiovascular risk factors such as vitamin D, different inflammatory markers or liver disease for non-alcoholic fat deposit. In this research we have studied a cohort of patients with type 1 diabetes mellitus from the Mediterranean area of Badalona, asymptomatic from a cardiovascular point of view and with more than 10 years of evolution of their disease, through clinical characterization, analysis of serological parameters of potential relevance such as adiponectin, YKL-40 and 25-hydroxyvitamin D, as well as liver ecographic evaluation for the detection of hepatic non-alcoholic steatosis. All the information extracted has been correlated with early atherosclerotic data obtained by measuring coronary artery calcification by computerized tomography and the measurement of the carotid intima-media thickness through ultrasound. As a result, our cohort, a significant sample of the population with type 1 diabetes mellitus in our area, has a very low prevalence of subclinical cardiovascular disease, approximately 10%. In addition, a good correlation between the results of carotid ultrasound and the quantification of coronary calcium by tomography has been detected, indicating the potential of these tests for the diagnosis of subclinical cardiovascular disease in patients with type 1 diabetes mellitus. The evaluation of the non-classical cardiovascular risk factors regarding the association with the presence of preclinical cardiovascular disease has discarded the concentrations of vitamin D and the serum markers such as adiponectin or YKL-40 but, opposite of that, in the univariate study of the association between the presence of liver steatosis and carotid atherosclerosis, a link was confirmed. It is concluded that, in our territory with recognized low cardiovascular risk, there is a very small prevalence of subclinical cardiovascular disease among patients with type 1 diabetes mellitus, which does not justify generalized screening, but that, in certain patients, we have diagnostic test for its detection. Therefore, in the study of the patient with type 1 diabetes mellitus from the Mediterranean area and, based on the data obtained, we can use the carotid ultrasound for detection and abdominal ultrasound for the stratification of the cardiovascular risk. This deeper understanding of the atherosclerosis of the patient with type 1 diabetes mellitus in our area, in terms of prevalence, diagnostic methods, severity and associated factors, helps us to design preventative, therapeutic and follow-up interventions that are potentially more targeted and effective.
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Perna, Barrull David. "Efecte del tractament prenatal amb betametasona en el desenvolupament de la diabetis mellitus tipus 1." Doctoral thesis, Universitat Autònoma de Barcelona, 2019. http://hdl.handle.net/10803/670183.
Full textAbstract:
La incidència de diabetis mellitus tipus 1 (DT1) està augmentant en tot el món en els últims anys i la causa d’aquest fet segueix sent desconeguda. Els factors ambientals són crucials en el desenvolupament de la DT1, però fins ara no han sigut profundament estudiats durant l’època prenatal. Els dos actors principals de la DT1, el sistema immunitari i els illots pancreàtics, estan en desenvolupament fins a l’última setmana abans del naixement i poden ser fàcilment alterats utilitzant fàrmacs. En aquest sentit, els glucocorticoides sintètics tenen potents efectes antiinflamatoris i immunosupressors i poden travessar la barrera materno-fetal. Aquesta família de molècules interaccionen amb el receptor de glucocorticoides que s’expressa de forma ubiqua a totes les cèl·lules. La betametasona és un glucocorticoide administrat a dones amb risc de part prematur per a millorar la salut perinatal del nadó al naixement gràcies a estimular la maduració dels pulmons fetals. Actualment, al mateix nivell que augmenten els nadons prematurs, augmenta l’ús de la betametasona. La hipòtesi d’aquest treball és que la betametasona influeix en la incidència de la DT1, mitjançant modificacions en el desenvolupament del sistema immunitari prenatal i de la cèl·lula β. L’objectiu principal de l’estudi és determinar l’efecte de la betametasona prenatal sobre la susceptibilitat de desenvolupar DT1.
Es va realitzar un estudi d’incidència en el model experimental de DT1, el ratolí No-Obès Diabètic (NOD). La betametasona prenatal va reduir la incidència de DT1 en la descendència femella del grup tractat (22%) respecte a la incidència del grup control (75%), correlacionant amb una disminució dels limfòcits infiltrants a l’illot. Notablement, la betametasona va induir hipotròfia del timus i alteracions en les subpoblacions del sistema immune en els ratolins nounats. El repertori de famílies Vβ del TCR de limfòcits T es va determinar en ratolins de 6 setmanes d’edat i es va observar una reducció en la freqüència de les famílies de Vβ autoreactives. La betametasona va provocar un efecte tòxic en els limfòcits no estimulats del ratolí. En les cèl·lules dendrítiques, la betametasona va induir un estat de resistència a la maduració, fet que va comportar una reducció en la seva producció de citocines i va aturar la proliferació autòloga de limfòcits T γδ i la seva secreció d’IL-17. L’efecte de la betametasona en la cèl·lula β es va determinar en la línia cel·lular NIT-1 de ratolí NOD, en pàncrees i en illots purificats de ratolí NOD. La betametasona disminuir la viabilitat de les cèl·lules NIT-1, evitant la proliferació cel·lular i reduint la secreció d’insulina. A més, La betametasona va induir una disminució de la molècula CD44 i un increment de MHC de classe I a la membrana de les cèl·lules NIT-1. D’altra banda, la betametasona va alterar l’expressió gènica en la línia cel·lular NIT-1, en el
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pàncrees i en els illots, afectant gens relacionats amb l’autoimmunitat, el metabolisme, la massa d’illots i inhibidors de la regulació immunitària. Per tal de realitzar una aproximació a l’efecte en humans, es va testar l’efecte de la betametasona en leucòcits humans. Es van utilitzar cèl·lules mononuclears de sang perifèrica i només es va observar un efecte tòxic en limfòcits B i monòcits. A més, dades epidemiològiques preliminars de pacients amb DT1 de l’HUGTiP apunten cap a l’efecte protector de la betametasona en el risc de desenvolupar DT1.
En conclusió, la betametasona protegeix contra la DT1 experimental mitjançant alteracions de la resposta immunitària i reduint el reconeixement autoimmune contra les cèl·lules β. Aquests resultats, juntament amb dades preliminars d’estudis en humans, recolzen l’efecteRecientemente la incidencia de diabetes mellitus tipo 1 (DT1) está aumentando en todo el mundo y la causa de este hecho sigue siendo desconocida. Los factores ambientales son cruciales en el desarrollo de la DT1, pero hasta el momento no han sido estudiados exhaustivamente durante la época prenatal. Los dos actores principales de la DT1, el sistema inmunitario y los islotes pancreáticos, se encuentran en desarrollo hasta la última semana antes del nacimiento y pueden ser fácilmente alterados por efecto de algunos fármacos. En este sentido, los glucocorticoides sintéticos tienen potentes efectos antiinflamatorios e inmunosupresores y pueden cruzar la barrera materno-fetal. Esta familia de moléculas interacciona con el receptor de glucocorticoides que se expresa de forma ubicua en todas las células. La betametasona es un glucocorticoide administrado a mujeres con riesgo de parto prematuro para mejorar la salud perinatal del bebé gracias a estimular la maduración de los pulmones fetales. En la actualidad, al mismo tiempo que aumentan los bebés prematuros, también aumenta la utilización de betametasona. La hipótesis de este trabajo es que la betametasona influye en la incidencia de DT1, mediante modificaciones en el desarrollo del sistema inmunitario prenatal y en la célula β. El objetivo principal del estudio es determinar el efecto de la betametasona en la susceptibilidad de desarrollar DT1. Se realizó un estudio de incidencia en el modelo experimental de DT1, el ratón No Obeso Diabético (NOD). La betametasona prenatal redujo la incidencia de DT1 en la descendencia femenina del grupo tratado (22%) respecto a la incidencia del grupo control (75%), correlacionando con una disminución de los linfocitos infiltrantes del islote. Notablemente, la betametasona indujo hipotrofia en el timo y alteraciones en las subpoblaciones del sistema inmunitario en los ratones recién nacidos. El repertorio de familias Vβ del TCR de los linfocitos T se determinó en ratones de 6 semanas de edad y se observó una reducción en la frecuencia de las familias Vβ autoreactivas. Además, provocó un efecto tóxico en los linfocitos no estimulados del ratón. En las células dendríticas, la betametasona indujo un estado de resistencia a la maduración, lo que comportó una reducción tanto en su capacidad de producir citocinas como una disminución de la proliferación autologa de linfocitos T γδ y secreción de IL-17. El efecto de la betametasona en la célula β se determinó en la línea celular NIT-1, en páncreas y en islotes purificados de ratón NOD. La betametasona redujo la viabilidad de las células NIT-1, evitando la proliferación celular y reduciendo la secreción de insulina. También, este fármaco indujo una disminución de la molécula CD44 y un incremento de MHC de clase I en la membrana de las células NIT-1. Por otro lado, la betametasona alteró la expresión génica en la línea celular NIT-1, en el páncreas y en los islotes murinos, afectando genes relacionados con la autoinmunidad, el metabolismo, la masa del islote e inhibidores de la regulación inmunitaria. Para realizar una aproximación al efecto en humanos, se determinó el efecto de la betametasona en leucocitos humanos. Se utilizaron células mononucleares de sangre periférica y observándose únicamente un efecto tóxico en linfocitos B y monocitos. Además, datos epidemiológicos preliminares recogidos de pacientes con DT1 del HUGTiP apuntan hacia el efecto protector de la betametasona en el riesgo de desarrollar DT1. En conclusión, la betametasona protege contra la DT1 experimental a través de alteraciones de la respuesta inmunitaria y reduciendo el reconocimiento autoinmune contra las células β. Estos resultados, junto datos preliminares de estudios en humanos, apoyan el efecto protector de la betametasona prenatal en el desarrollo de la DT1
The incidence of type 1 diabetes (T1D) has been steadily increasing worldwide in the last years and the cause remains to be elucidated. Environmental factors are crucial in the pathogenesis of T1D, but these factors have not been studied thoroughly during the prenatal stage. The two actors in the development of T1D, the immune system and the pancreatic islets, are still developing until the last weeks before delivery and can be easily altered by drugs. In this sense, synthetic glucocorticoids have powerful anti-inflammatory and immunosuppressive effects and can cross the maternofoetal barrier. This family of drugs interacts with the ubiquitously expressed glucocorticoid receptor. Betamethasone is a glucocorticoid administered to women at risk of preterm delivery to improve perinatal outcome after birth by stimulating foetal lung maturation. At the same time that premature new-borns are increasing, the use of betamethasone is raising. The hypothesis of this work is that betamethasone may affect the development of foetal immune system and pancreas, thus influencing the risk of developing T1D in the offspring. The aim of this study was to determine the effect of prenatal betamethasone on T1D susceptibility. An incidence study was performed in the experimental model of T1D, the non-obese diabetic (NOD) mice. Prenatal betamethasone administration caused a reduction in T1D incidence in the female offspring from the treated group (incidence of 22%) when compared to the sham group (incidence of 75%), correlating with a decrease in infiltrating lymphocytes in the islets. Remarkably, betamethasone caused thymus hypotrophy and alterations in immune cells subsets in new-born mice. The TCR Vβ T cell repertoire was assessed in 6 weeks-old mice and a clear decrease in the frequency of autoreactive Vβ families was found. Betamethasone caused in vitro toxicity to resting mouse lymphocytes. In dendritic cells, betamethasone induce a maturation-resistant status, thus decreasing their cytokine production and impairing autologous γδ T lymphocyte proliferation induction ability and secretion of IL-17. The effect of betamethasone on β-cells was determined in the NOD β-cell line NIT-1, in whole pancreas and in purified islets from NOD mice. Betamethasone effects were detrimental for NIT-1 cell viability, arresting cell growth and reducing insulin secretion. Downregulation of CD44 membrane expression and upregulation of MHC class I expression was induced by this glucocorticoid in NIT-1 cells. Betamethasone also altered gene expression in NIT-1 cell line, pancreas and islets, affecting genes related to autoimmunity, metabolism, islet mass and immune checkpoint inhibitors. In order to move forward, human peripheral blood mononuclear cells were used to determine betamethasone effects. A toxic effect was observed only in monocytes and B cells. Moreover, preliminary epidemiological data from paediatric patients with T1D from the Germans Trias i Pujol Hospital reinforces the putative the protective effect of betamethasone in the risk of developing T1D. In conclusion, betamethasone has a protective effect against experimental T1D by altering the immune system response and potentially decreasing autoimmune recognition of β-cells. These results, together with our preliminary data from human studies, support a protective effect of prenatal betamethasone in T1D development.
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Roig, Bourgine Bàrbara. "Expressió del receptor domini discoidina 1 (DDR1) en cervell huma. Relació amb l'esquizofrènia." Doctoral thesis, Universitat Rovira i Virgili, 2007. http://hdl.handle.net/10803/8860.
Full textAbstract:
L'esquizofrènia és una de les psicosis més comunes que té una prevalença d'un 1% en la població mundial i una etiologia desconeguda. Una de les hipòtesis etiopatològiques més recolzades per l'esquizofrènia és la teoria del neurodesenvolupament la qual postula que l'origen de la esquizofrènia tindria lloc per alteracions de la neurogènesi i gliogènesi en les etapes del desenvolupament perinatal. Nombrosos estudis han descrit diverses alteracions de la mielina (substància blanca del cervell) en pacients esquizofrènics. La mielinització dels axons és important per una correcta transmissió del senyal entre neurones. Les cèl·lules responsables de sintetitzar mielina per embolcallar el axons en el cervell són els oligodendròcits. En humans els majors pics del procés de mielinització ocorren en la etapa perinatal, infantesa i adolescència. En aquesta última etapa és on es manifesten majoritàriament els primers símptomes de l'esquizofrènia.Diversos estudis de lligament apunten a que a la regió cromosòmica 6p hi podria haver un gen o gens de susceptibilitat per l'esquizofrènia. El nostre grup va escollir un gen d'aquesta regió, el gen que codifica pel Receptor Domini Discoidina 1 (DDR1), com a candidat per l'esquizofrènia. Se sap que DDR1 és un receptor tirosina quinasa que s'expressa de forma molt important en zones proliferatives durant el neurodesenvolupament del cervell de rata i ratolí i també s'ha vist que s'expressa en cervell humà. DDR1 té com lligant el col·lagen, el qual promou la diferenciació i proliferació de les cèl·lules neuroepitelials en rates. El nostre grup ha observat una important expressió de DDR1 en la substància blanca i en concret en els oligodendròcits durant el desenvolupament pre i postnatal en ratolins. A demés l'expressió d'aquest receptor segueix un patró espacio-temporal al procés de mielinització.
En la present tesi doctoral hem estudiat per primera vegada en detall el patró d'expressió gènica i proteïca del receptor DDR1 en cervell humà mitjançant tècniques específiques d'hibridació in situ, immunohistoquímica i de quantificació d'RNAm. Hem trobat que existeix una associació positiva tan a nivell gènic com haplotípic de DDR1 amb l'esquizofrènia mitjançant un estudi d'anàlisi de variants tipus SNPs en una mostra de casos i control.
També hem descrit per primera vegada que DDR1 és una proteïna de la mielina en cervell humà i que entre les 5 diferents isoformes que es coneixen només les isoformes DDR1c i DDR1a es relacionen amb la mielina. D'aquesta tesi es deriven les següents aportacions científiques:
- Roig B, Virgos C, Franco N, Martorell L, Valero J, Costas J, Carracedo A, Labad A, Vilella E. The discoidin domain receptor 1 as a novel susceptibility gene for schizophrenia. Molecular Psychiatry. 2007. doi: 10.1038/sj.mp.4001995. IF: 11.8
- Roig B, Franco-Pons N, Martorell L, Tomàs J, Costas J, Vogel WF, Vilella E. Identification of the tyrosine kinase receptor discoidin domain 1 (DDR1) as a novel myelin protein. Sotmés a revisió a la revista Glia. IF: 4.1
- Roig B, Franco-Pons N, Martorell L, Vilella E. Quantitative analysis of DDR1 mRNA expression in normal and schizophrenic brain. Manuscrit en preparació.
Schizophrenia is one of the most common psychoses in the world today. It has a prevalence of 1% in the population and is of unknown etiology. One of the most widely accepted etiopathogenic hypotheses for schizophrenia is neurodevelopmental theory, which postulates that schizophrenia originates from a variety of neurogenetic and gliogenetic disorders during perinatal development. Many studies have reported that schizophrenic patients have alterations in their myelin (white matter of the brain). Axons must be myelinated if signals are to be properly transmitted between neurons. The cells that form the myelin sheaths of the axons in the CNS are the oligodendrocytes.
In humans, the myelination process peaks in the perinatal, childhood and adolescence stages. It is during this last stage that the symptoms of schizophrenia become manifest. Several linkage studies indicate that the 6p chromosomal region may contain one or more susceptibility genes for schizophrenia. Our group chose a gene in this region, the gene encoding the discoidin domain receptor 1 (DDR1), as a candidate gene for schizophrenia.
DDR1 is known to be a receptor tyrosine kinase which is highly expressed in proliferative areas during murine brain development, and has also been shown to be expressed in human brain. The DDR1 ligand is collagen, which promotes the proliferation and differentiation of the neurophitelial cells in rats. Our group has observed that DDR1 is significantly expressed in the white matter and particularly in oligodendrocytes during pre- and postnatal development in mice. Furthermore, the expression of this receptor follows a spatial-temporal pattern similar to the process of myelination.
In this doctoral thesis we have made the first detailed study of the pattern of gene and protein expression of DDR1 in human brain, using specific techniques such as in situ hybridization, immunohistochemistry and quantification of RNAm. We found a positive association of DDR1 with schizophrenia in a case-control association study using markers of the SNP (single nucleotide polymorphism) type.
We have also reported for the first time that DDR1 is a myelin protein in the human brain and that of the five different isoforms that are known only isoforms DDR1c and DDR1a are related to the myelin.
The following scientific articles have been written as a result of this doctoral thesis:
- Roig B, Virgos C, Franco N, Martorell L, Valero J, Costas J, Carracedo A, Labad A, Vilella E. The discoidin domain receptor 1 as a novel susceptibility gene for schizophrenia. Molecular Psychiatry. 2007. doi: 10.1038/sj.mp.4001995. IF: 11.8
- Roig B, Franco-Pons N, Martorell L, Tomàs J, Costas J, Vogel WF, Vilella E. Identification of the tyrosine kinase receptor discoidin domain 1 (DDR1) as a novel myelin protein. Submitted to Glia. IF: 4.1
- Roig B, Franco-Pons N, Martorell L, Vilella E. Quantitative analysis of DDR1 mRNA expression in normal and schizophrenic brain. Manuscript in preparation.
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Mumper, Eric Keith. "Mixotrophic Magnetosome-Dependent Magnetoautotrophic Metabolism of Model Magnetototactic Bacterium Magnetospirillum magneticum AMB-1." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1551880645784717.
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Aparicio, Prats Ester. "Factors Predictius de la Resposta al Tractament contra el VHC, amb Interferó-α i Ribavirina, en Pacients Coinfectats amb el VHC i el VIH-1." Doctoral thesis, Universitat Autònoma de Barcelona, 2011. http://hdl.handle.net/10803/83944.
Full textAbstract:
El paper de la proteasa NS3/4A de l'hepatitis C (VHC) en el bloqueig de la via de
senyalització implicada en la producció dels interferons alfa/beta (IFN-α/β) suggereix
una relació entre l'activitat proteolítica de la NS3/4A i la resposta a la teràpia basada en
IFN. Per identificar els factors virals associats a la resposta al tractament contra el VHC,
es va analitzar la composició de les quasiespècies de la proteasa NS3/4A, de 56 mostres
basals, provinents de pacients coinfectats amb el VHC de genotip 1 i el VIH de tipus
1, tractats a la nostra unitat clínica amb IFN pegilat (pegIFN) més ribavirina (RBV).
L'eficiència catalítica de la quasiespècie dominant (és a dir, la més abundant) va ser
assajada davant el punt de tall Cardif i es va correlacionar amb els resultats obtinguts
del tractament. Un total de 1.745 clons es van aïllar i seqüenciar. L’heterogeneïtat de les
quasiespècies i valors de l'entropia de Shannon, ambdós magnituds expressades en
nucleòtids, van resultar significativament menors, entre el grup de pacients que van
obtenir la resposta al tractament (P < 0,05). També, es va trobar una correlació entre
l'eficàcia catalítica de la proteasa NS3/4A davant de Cardif i la resposta al tractament.
Les proteases de pacients responedors eren més eficients en el processament de Cardif
(error ± estàndard de la mitjana [SEM], 0,8960 ±0,05568, n = 19) que les proteases
originàries dels no responedors (mitjana ±
SEM, 0,7269 ±
0,05306, n = 37, p <
0,05). Finalment, la distància genètica expressada en aminoàcids, va ser
significativament menor entre els pacients amb l’al · lel de risc interleucina-28B (IL-
28B) (P <0,01), el que suggereix que els portadors de l'al · lel de risc IL28B exerceixen
una menor pressió de selecció positiva sobre la proteasa NS3/4A. Eficiència de la
proteasa NS3/4A, en processar Cardif pot estar associada amb la resposta al tractament
pegIFN-RBV, com es mostra en la nostra cohort de pacients coinfectats VHC-VIH. Una
major heterogeneïtat de la proteasa NS3/4A en nucleòtids i valors més alts de l'entropia
de Shannon, també en nucleòtids, en pacients que no responen al tractament, suggereix
que una menor complexitat de les quasiespècies del VHC pot afavorir una millor
resposta a pegIFN-RBV.The role of the hepatitis C virus (HCV) NS3/4A protease in ablating the signaling pathway involved in the production of alpha/beta interferon (IFN-‐α/β) suggests a relationship between NS3/4A proteolytic activity and a patient’s response to IFN-‐ based therapy. To identify viral factors associated with the HCV treatment response, we analyzed the pretreatment NS3/4A protease gene quasispecies composition of 56 HCV genotype 1–HIV-‐1-‐coinfected patients treated in our clinic with pegylated IFN (pegIFN) plus ribavirin (RBV). The catalytic efficiency of the dominant (i.e., the most abundant) quasispecies was also assayed for Cardif cleavage and correlated with treatment outcome. A total of 1,745 clones were isolated and sequenced. Significantly less nucleotide quasispecies heterogeneity and lower Shannon entropy values were detected within the responder group (P < 0.05). A correlation was also found between the efficiency of NS3/4A protease Cardif cleavage and therapy outcome. Proteases from sustained responder patients were more efficient at processing Cardif (mean standard error of the mean [SEM], 0.8960 ± 0.05568; n = 19) than proteases from nonresponders (mean ± SEM, 0.7269 ± 0.05306; n = 37; P < 0.05). Finally, the amino acid p distance (the proportion [p] of nucleotide sites at which two sequences being compared are different) was significantly shorter in patients with an interleukin-‐28B (IL-‐28B) risk allele (P < 0.01), suggesting that IL-‐28B risk allele carriers exert a lower positive selection pressure on the NS3/4A protease. NS3/4A protease efficiency in cleaving Cardif may be associated with the pegIFN-‐RBV treatment response, as shown in our cohort of HIV-‐HCVcoinfected patients. Greater NS3/4A nucleotide heterogeneity and higher Shannon entropy values in nonresponders suggest that less HCV quasispecies complexity may favor a better response to pegIFN-‐RBV.
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Alonso, Pedrol Núria. "Estudi de paràmetres immunològics i hormonals gàstrics en pacients amb diabetis mellitus tipus 1." Doctoral thesis, Universitat Autònoma de Barcelona, 2010. http://hdl.handle.net/10803/50995.
Full textAbstract:
La diabetis mellitus tipus 1 (DM1) és una malaltia autoimmunitària deguda a una destrucció sel·lectiva de les cèl·lules beta pancreàtiques. Els pacients amb DM1 presenten un increment de la prevalença d’altres malalties autoimmunitàries associades, entre les quals hi ha la gastritis autoimmunitària o tipus A que en la seva fase més evolucionada es manifesta clínicament amb una anèmia perniciosa. La gastritis crònica atròfica tipus A cursa, de forma característica, amb una atròfia de la mucosa del cos i fundus gàstrics. En canvi, la mucosa de l’antre està conservada. Els diferents treballs publicats en aquesta tesi s’han centrat en la valoració de la utilitat de varis paràmetres immunològics i hormonals gàstrics per a l’estudi de la gastritis autoimmunitària en els pacients amb DM1.
Els diferents treballs publicats en aquesta tesi s’han centrat en la valoració de la utilitat de varis paràmetres immunològics i hormonals gàstrics per a l’estudi de la gastritis autoimmunitària o tipus A en els pacients amb DM1.
Els paràmetres que s’han avaluat han estat: la concentració sèrica de pepsinogen I (pèptid que es sintetiza a les cèl·lules principals del cos gàstric), els anticossos anti-cèl·lula parietal gàstrica, la concentració sèrica de cobalamina o vitamina B12, la concentració sèrica de gastrina, la concentració plasmàtica de ghrelina (pèptid de 28 aa sintetizat a les cel·lules neuroendocrines de la mucosa gàstrica) i, finalment, l’anàlisi en sang perifèrica de les cèl·lules T reguladores que són un subgrup de limfòcits T implicats en el control de l’autoimmunitat.
Els resultats obtinguts en els diferents treballs han mostrat que:
1.- La determinació de la concentració sèrica de pepsinogen I juntament amb uns anticossos anti-cèl·lula parietal gàstrica són el millor marcador bioquímic per al cribratge de la gastritis autoimmunitària en els pacients amb DM1. A més, aquesta combinació permet detectar al subgrup de pacients amb DM1 que presenten un major risc de presentar concentracions sèriques baixes de cobalamina que, de confirmar-se, haurien de ser tractades degut a les possibles complicacions neurològiques associades al seu déficit.
2.- La concentració plasmàtica de ghrelina total no és un bon marcador d’atròfia de la mucosa gàstrica en els pacients amb DM1 i gastritis tipus A.
3.- La concentració plasmàtica total de ghrelina no permet identificar al subgrup de pacients amb hiperplàsia de les cèl·lules neuroendocrines dintre del grup de pacients amb gastritis tipus A.
4.- Els pacients amb DM1 i gastritis autoimmunitària presenten, en comparació amb el grup de pacients amb DM1 sense altres malalties autoimmunitàries associades, un percentatge major de cèl·lules T reguladores a sang perifèrica.
5.- Els pacients amb DM1 i gastritis tipus A o autoimmunitària en fase atròfica presenten un menor percentatge de cèl·lules T reguladores a la mucosa gàstrica que els pacients amb gastritis atròfica de causa infecciosa (Helicobacter pylori). En canvi, el percentatge de cèl·lules T reguladores a la mucosa gàstrica dels pacients amb DM1 gastritis tipus A és superior a l’observat a la mucosa gàstrica normal. Aquest fet, podria posar de manifest la influència del percentatge de cèl·lules T reguladores in situ necessari per a la cronificació d’una gastritis autoimmunitària o infecciosa.Type 1 diabetes mellitus (T1D) is the consequence of the autoimmune destruction of pancreatic beta cells of the islets of Langerhans. T1D patients show an increased prevalence of other associated organ-specific autoimmune diseases. Type A chronic atrophic gastritis (CAG) is an autoimmune disease that involves the fundus and body of the stomach and spares the antrum. In the later stage of the disease, pernicious anaemia may result from cobalamin deficiency. The papers published in this thesis have focused on assessing the usefulness of several hormonal and immunological parameters for the study of autoimmune gastritis in patients with T1D. The parameters evaluated were: serum pepsinogen I concentrations (a peptide secreted by zymogenic cells in the body and fundus of the stomach), gastric parietal cell antibodies, serum cobalamin or vitamin B12 concentrations, plasma ghrelin concentrations (a 28-aminoacid peptide mainly synthesised in the neuroendocrine cells of the stomach) and finally, the analysis of regulatory T cells (Tregs), which are a subset of T lymphocytes involved in controlling autoimmunity. The results of the studies have shown that: 1.- The determination of serum pepsinogen I concentrations together with gastric parietal cell antibodies are the best biochemical marker for the screening of autoimmune gastritis in patients with T1D. The determination of both parameters is more useful than each other separately, for the identification of those patients with a higher risk to present cobalamin deficiency, that in case to be confirmed, should be treated given its possible associated neuropathy. 2.- Plasma ghrelin concentration is not a good biochemical marker of gastric mucosa atrophy in T1D patients with type A CAG. 3.- Plasma ghrelin concentration doesn`t predict neuroendocrine cell hyperplasia in those patients with T1D and type A CAG. 4.- Type 1 diabetic patients with chronic autoimmune gastritis (type A) have a higher frequency of Tregs in peripheral blood compared to T1D patients with no evidence of type A CAG or other associated autoantibodies, and healthy controls. 5.- The number of Tregs in gastric mucosa of T1D patients with type A-CAG is lower than in those with Helicobacter pylori-induced CAG, although higher than that observed in normal gastric mucosa. This fact, underlies the influence of the percentage of Tregs in situ necessary for controlling the chronification of an autoimmune or infectious gastritis.
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Rioux, Jean-Baptiste. "Du génome à la protéine : caractérisation d'une nouvelle actin-like chez Magnetospirillum Magneticum AMB-1." Thesis, Aix-Marseille 2, 2011. http://www.theses.fr/2011AIX22016/document.
Full textAbstract:
Les bactéries magnétotactiques synthétisent des organites spécialisés appelés magnétosomes. Ils sont composés d'un cristal magnétique entouré d'une membrane et de protéines spécifiques. Arrangés en chaîne dans la bactérie, ils orientent la bactérie dans le champ magnétique, ce qui simplifierait sa recherche d’environnements microaérophiles. Dans le génome de toutes les souches magnétotactiques séquencées, l'îlot génomique de magnétotaxie contient les gènes impliqués dans la formation des magnétosomes. Nous avons procédé à l’annotation du génome de la souche magnétotactique marine QH-2 et montré que la région du génome codant les gènes de la magnétotaxie n'est, dans ce cas, pas définie comme un îlot génomique, bien qu’elle ait été acquise par transfert latéral de gènes. Dans le génome de M. magneticum AMB-1, nous avons identifié un nouvel îlot génomique de petite taille que nous avons appelé l'îlet de magnétotaxie portant 7 gènes homologues à des gènes liés à la synthèse des magnétosomes. Pour répondre à la question de la fonction biologique de cet îlet génomique, nous avons examiné le rôle de l'un des sept gènes, mamK-like. MamK-like exprimée dans E. coli forme des filaments, comme observé pour MamK. La polymérisation in vitro des deux protéines est également comparable, mais présente des différences structurales. En outre, nous démontrons que mamK-like est transcrite dans AMB-1 de type sauvage et dans le mutant ΔmamK. Par immuno-marquage, nous montrons la présence d'un filament dans le mutant ΔmamK, probablement dû à MamK-like. Nous émettons l'hypothèse que ce filament contribue à maintenir l’organisation en chaîne des magnétosomes dans la souche mutanteMagnetotactic bacteria synthesise specialised organelles called magnetosomes. They are composed of a magnetic crystal surrounded by a lipid bilayer and specific proteins. Arranged in chains, they orient magnetotactic bacteria in the geomagnetic field, thereby simplifying their search for their microaerophilic environments. In each sequenced magnetotactic strain, the magnetotaxis genomic island contains the genes involved in magnetosomes formation. Our annotation of the newly sequenced genome of the magnetotactic strain QH-2 shows that the region coding the magnetotaxis genes is not a genomic island, though it has been acquired by lateral genes transfer. In the genome of M. magneticum AMB-1 we identified a new, small genomic island we termed the magnetotaxis islet, encoding 7 genes homologous to genes related to the magnetosomes synthesis. To assess the question of the biological function of this genomic islet, we further investigated the role of one of the seven genes, mamK-like. Filaments were observed in E. coli cells expressing MamK-like-Venus fusion by fluorescence microscopy. In vitro polymerization of both isoforms is comparable, though some differences are present at the structural level. In addition, we demonstrate that mamK-like is transcribed in AMB-1 wild-type and ΔmamK mutant cells. Immunolabelling assay using an anti-MamK antibody reveals the presence of a filament in the ΔmamK mutant. We hypothesise that this filament is due to MamK-like and that it helps maintaining a chain-like organisation of magnetosomes in the mutant strain
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Shirkhani, Khojasteh. "Bioactivity of new AmB-PMA nanoparticle in prophylaxis and treatment of transplant-related invasive aspergillosis." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/24157.
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Aspergillus species are opportunistic mould pathogens that can cause a wide variety of pulmonary diseases. They are mainly caused by Aspergillus fumigatus (Munoz et al., 2006). Germination of conidia in hosts with a susceptible immune system is the first step in Aspergillus infection, and invasive aspergillosis (IA) is a major cause of mortality in transplant patients. Due to the increased occurrence of IA in high-risk populations, prophylaxis against IA is important. Prophylactic prevention of life threatening infections with drugs is now the preferred clinical strategy for these patients rather than treating the disease after it has become established. Inhaled amphotericin B (AmB) has potential for preventing IA and it has been reported to decrease the incidence of IA in solid organ transplant patients (Arthur et al., 2004). I have generated a new respiratory formulation of AmB (AmB-PMA) with a commercially available high purity, low polydispersity and non-toxic poly methacrylic acid sodium salt (PMA-Na). The chemical synthesis was optimized and showed that AmB-PMA complex was effective against A. fumigatus and was also less toxic than Fungizone in-vitro. The efficacy of AmB-PMA was determined in-vivo in BALB/c and C57BL/6 mice. Mice were infected intranasally with A. fumigatus CEA10 and treated with AmB-PMA by the nasal and nebulisation routes. In this thesis, the optimum routes of in-vivo administration, dosing regimens and treatment frequency were defined. Disease progression in A. fumigatus-infected BALB/c and C57BL/6 mice was monitored by histology, qPCR analysis of chemokine and cytokine responses in mouse lung, colony forming unit (CFU) and qPCR for Aspergillus ribosomal 28S rRNA. The results showed a significant reduction in CFU and DNA fungal load in AmB-PMA infected mice as compared to infected untreated mice. In addition, AmB-PMA could also affect cytokine production by increasing IFN-γ production and reducing MIP-1β, TNF-α and IL-10 as compared to infected untreated mice. However, the increase in IFN-γ production was not statistically significant when compared to infected untreated mice. My thesis demonstrates that a new low-cost AmB based PMA-Na polymer antifungal drug can be successfully given by the aerosol route to immuno-suppressed mice by nebulisation to prevent IA.
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Guilà, Matarin Meritxell. "Estudi de l’evolució de l’envolta del VIH-1 en pacients infectats sotmesos a vacunació terapèutica amb virus autòleg inactivat." Doctoral thesis, Universitat de Barcelona, 2011. http://hdl.handle.net/10803/78937.
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La infecció pel virus de la immunodeficiència humana (VIH) constitueix una de les epidèmies més importants actualment. El VIH es caracteritza per la seva elevada variabilitat genètica al llarg de la seva història natural. Les múltiples variants existents dins del mateix hoste, el que es coneix com quasiespècies, constitueixen una font d'adaptabilitat del virus, ja que permeten la disponibilitat d'una variant d'escapament davant una possible pressió selectiva en l'ambient (resposta immune, fàrmacs antiretrovirals, etc) .
Malgrat els grans avenços en el desenvolupament de tractaments eficaços, actualment no ha estat possible l'eradicació de la infecció. El tractament antiretroviral de gran activitat (TARGA) ha disminuït significativament la morbi-mortalitat associada a la infecció pel VIH, però, no aconsegueix l'eliminació del virus. Conseqüència directa d'això és que, en suspendre'l, el virus reapareix en sang perifèrica, i caldrà mantenir el tractament de per vida, amb els seus costos tant a nivell d'efectes secundaris com econòmics. Davant aquesta situació, ha estat necessari el disseny de teràpies alternatives com les teràpies immunomediades (interrupcions estructurades del tractament o vacunes terapèutiques), enfocades a estimular el sistema immunològic del pacient per poder suspendre el TARGA de forma definitiva o, almenys, durant períodes variables de temps.
Avui en dia no es coneixen amb exactitud els efectes que pugui tenir la variabilitat del VIH en les teràpies immunomediades, i l'interès del nostre estudi parteix d'aquesta premissa. Per això, l'objectiu d'aquesta tesi és analitzar, per primera vegada, l'evolució del virus en pacients sotmesos a vacunació terapèutica (en el nostre cas, una vacuna terapèutica de cèl•lules dendrítiques polsades amb el virus autòleg inactivat per calor).La infección por el virus de la inmunodeficiencia humana (VIH) constituye una de las epidemias más importantes actualmente. El VIH se caracteriza por su elevada variabilidad genética a lo largo de su historia natural. Las múltiples variantes existentes dentro del mismo huésped, lo que se conoce como cuasiespecie, constituyen una fuente de adaptabilidad del virus, pues permiten la disponibilidad de una variante de escape frente una posible presión selectiva en el ambiente (respuesta inmune, fármacos antiretrovirales, etc). A pesar de los grandes avances en el desarrollo de tratamientos eficaces, actualmente no ha sido posible la erradicación de la infección. El tratamiento antirretroviral de gran actividad (TARGA) ha disminuido significativamente la morbi-mortalidad asociada a la infección por el VIH, no obstante, no consigue la eliminación del virus. Consecuencia directa de ello es que, al suspenderlo, el virus reaparece en sangre periférica, siendo necesario mantener el tratamiento de por vida, con sus costes tanto a nivel de efectos secundarios como económicos. Frente esta situación, ha sido necesario el diseño de terapias alternativas como las terapias inmunomediadas (interrupciones estructuradas del tratamiento o vacunas terapéuticas), enfocadas a estimular el sistema inmunológico del paciente para poder suspender el TARGA de forma definitiva o, al menos, durante períodos variables de tiempo. Hoy en día no se conocen con exactitud los efectos que pueda tener la variabilidad del VIH en las terapias inmunomediadas, y el interés de nuestro estudio parte de esta premisa. Por ello, el objetivo de esta tesis es analizar, por primera vez, la evolución del virus en pacientes sometidos a vacunación terapéutica (en nuestro caso, una vacuna terapéutica de células dendríticas pulsadas con el virus autólogo inactivado por calor).
Human Immunodeficiency Virus (HIV) infection is one of the largest epidemics today. HIV is characterized by high genetic variability throughout its natural history. Multiple variants exist within the same host, which is known as quasispecies. These quasispecies are a source of adaptability of the virus, and allow the availability of alternative escape variants against a possible selective pressure in the environment (immune response, antiretroviral drugs, etc). Despite the great advances in the development of effective treatments, now has not been possible to eradicate the infection. Antiretroviral therapy (HAART) has significantly decreased morbidity and mortality associated with HIV infection, however, it fails to eliminate the virus. Direct consequence is that, when HAART is stopped, virus rebound in peripheral blood, being necessary to maintain treatment for life, with its costs both in terms of side effects and economic burden. Facing this situation, it has been necessary to design alternative therapies such as immune-mediated therapies (structured treatment interruptions or therapeutic vaccines), aimed to stimulate the patient's immune system to permanently remove HAART or, at least, for varying periods of time. Today, effects of the variability of HIV in immune-mediated therapies are not exactly known , and the interest of our study is based on this premise. Therefore, the objective of this thesis is to analyze, for the first time, the evolution of HIV in patients undergoing therapeutic vaccination (in our case, a therapeutic vaccine based on dendritic cells pulsed with autologous heat-inactivated virus).
Books on the topic "Amb a 1"
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United States. Dept. of the Air Force., ed. UH-1 Huey. [Dover Air Force Base, Del.?: AMC Museum?, 2004.
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Janata, Alfred. Kurden: Azadi, Freiheit in den Bergen : Schallaburg, 17. Mai-1. November 1992. Wien: Amt der NÖ Landesregierung, Abt. III/2 Kulturabt., 1992.
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Stone, Shararah. Characterisation and linkage mapping of C-1 negative mutants of Methylbacterium extorquens AM1. Uxbridge: Brunel University, 1989.
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Bunte, Hermann-Josef. Allgemeine Geschäftsbedingungen und Sonderbedingungen der Kreditinstitute: Neuere Entwicklungen sowie Änderung der AGB zum 1. Januar 1986. Frankfurt am Main: Verlag Wertpapier-Mitteilungen, 1986.
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Contes amb animals. Susaeta, 2002.
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Green, John Patrick. Els InvestiGators 1 - Agents amb moltes dents. ALFAGUARA, 2022.
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Dufseth, Rhonda. MXT144UD-AMT/mXT144UD-AMB 1. 0 Datasheet. Microchip Technology Incorporated, 2020.
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Dufseth, Rhonda. MXT288UD-AMT/mXT288UD-AMB 1. 0 Datasheet. Microchip Technology Incorporated, 2020.
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Anderson, Julie. MXT144UD-AMT/mXT144UD-AMB 1. 0 Advance Datasheet. Microchip Technology Incorporated, 2019.
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Dufseth, Rhonda. MXT144UD-AMT/mXT144UD-AMB 1. 0 Product Brief. Microchip Technology Incorporated, 2020.
Find full textBook chapters on the topic "Amb a 1"
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Rogers, Bruce L., Julian F. Bond, Jay P. Morgenstern, Catherine M. Counsell, and Irwin J. Griffith. "Immunological Characterization of the Major Ragweed Allergens Amb a I and Amb a II." In Pollen Biotechnology, 211–34. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4757-0235-4_11.
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Rafnar, Thorunn, William J. Metzler, and David G. Marsh. "The Amb V Allergens from Ragweed." In Pollen Biotechnology, 235–44. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4757-0235-4_12.
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Yoon, Se Young, Zongli Lin, and Paul E. Allaire. "Design of AMB Supported Centrifugal Compressor." In Advances in Industrial Control, 89–124. London: Springer London, 2013. http://dx.doi.org/10.1007/978-1-4471-4240-9_4.
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Tay, Andy Kah Ping. "Phenotypic Selection of Magnetospirillum magneticum (AMB-1) Over-Producers Using Magnetic Ratcheting." In Acute and Chronic Neural Stimulation via Mechano-Sensitive Ion Channels, 61–70. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-69059-9_4.
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Yang, Chen-Dong, Haruko Takeyama, Tsuyoshi Tanaka, Aki Hasegawa, and Tadashi Matsunaga. "Synthesis of Bacterial Magnetic Particles During Cell Cycle of Magnetospirillum magneticum AMB-1." In Twenty-Second Symposium on Biotechnology for Fuels and Chemicals, 155–60. Totowa, NJ: Humana Press, 2001. http://dx.doi.org/10.1007/978-1-4612-0217-2_13.
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Wahyudi, Aris Tri, Haruko Takeyama, and Tadashi Matsunaga. "Isolation of Magnetospirillum magneticum AMB-1 Mutants Defective in Bacterial Magnetic Particle Synthesis by Transposon Mutagenesis." In Twenty-Second Symposium on Biotechnology for Fuels and Chemicals, 147–54. Totowa, NJ: Humana Press, 2001. http://dx.doi.org/10.1007/978-1-4612-0217-2_12.
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Okamura, Yoshiko, Haruko Takeyama, and Tadashi Matsunaga. "Two-Dimensional Analysis of Proteins Specific to the Bacterial Magnetic Particle Membrane from Magnetospirillum sp. AMB-1." In Twenty-First Symposium on Biotechnology for Fuels and Chemicals, 441–46. Totowa, NJ: Humana Press, 2000. http://dx.doi.org/10.1007/978-1-4612-1392-5_35.
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Matsunaga, Tadashi, Shinji Kamiya, and Noriyuki Tsujimura. "Production of a Protein (Enzyme, Antibody, Protein A)-Magnetite Complex by Genetically Engineered Magnetic Bacteria Magnetospirillum Sp. AMB-1." In Scientific and Clinical Applications of Magnetic Carriers, 287–94. Boston, MA: Springer US, 1997. http://dx.doi.org/10.1007/978-1-4757-6482-6_20.
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Abrams, David B., J. Rick Turner, Linda C. Baumann, Alyssa Karel, Susan E. Collins, Katie Witkiewitz, Terry Fulmer, et al. "AMI." In Encyclopedia of Behavioral Medicine, 85. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4419-1005-9_100065.
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Kuwert, Joachim. "Gegenstand der Versicherung (§ 1 AHB)." In Allgemeine Haftpflichtversicherung, 25–51. Wiesbaden: Gabler Verlag, 1988. http://dx.doi.org/10.1007/978-3-663-14837-1_3.
Full textConference papers on the topic "Amb a 1"
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Yu, Jiangfan, Huanbing Yu, Tiantian Xu, and Li Zhang. "Magnetic control of AMB-1 magnetotactic bacteria for micromanipulation." In 2015 IEEE International Conference on Automation Science and Engineering (CASE). IEEE, 2015. http://dx.doi.org/10.1109/coase.2015.7294331.
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Zhang, Yuhong, Shiying Ren, Hongqing Wu, and Tian Xiao. "Magnetosome Assembling and Optimization of Growth Conditions of the Magnetospirillum Magneticum AMB-1 Strain." In 2008 2nd International Conference on Bioinformatics and Biomedical Engineering. IEEE, 2008. http://dx.doi.org/10.1109/icbbe.2008.686.
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González, Lina M., Warren C. Ruder, William C. Messner, and Philip R. LeDuc. "Sensing of Local, Highly Concentrated Magnetic Field Gradients in Magnetotactic Bacteria Induces Motility Reversal." In ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80447.
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Many motile unicellular organisms have evolved specialized behaviors for detecting and responding to chemical gradients (chemotaxis) or oxygen (aerotaxis), while magnetotactic bacteria sense magnetic fields to align their direction of movement. Herein we show that Magnetospirillum magneticum (AMB-1) have the ability to sense and respond not only to the direction of magnetic fields of naturally occurring magnitude, but also to local, highly concentrated magnetic field gradients that do not occur in their natural environment. We imposed these gradients through our system integrating Helmholtz coils and permalloy (Ni80Fe20) microstructures. The AMB-1 exhibit three distinct behaviors as they approached gradients near the microstructures—unidirectional, single direction reversal, and double direction reversal. These results indicate previously unknown capabilities of the magnetic sensing systems of AMB-1.
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Siva Srinivas, Rangavajhala, Rajiv Tiwari, and Ch Kanna Babu. "Interaction Between Unbalance and Misalignment Responses in Flexibly Coupled Rotor Systems Integrated With AMB." In ASME 2017 Gas Turbine India Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gtindia2017-4535.
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This paper studies the rotor dynamic behavior of misaligned-coupled rotor systems integrated with active magnetic bearings. The simplest possible numerical model has been derived with a 4-degree of freedom two coupled Jeffcott rotor systems. The effect of flexible coupling on the interaction between the response due to unbalance and misalignment has been studied. To demonstrate the influence three cases have been considered a) pure misalignment b) pure unbalance c) presence of both unbalance and misalignment. This is an original attempt considering the standard practice of using beam element based finite element modeling techniques for such systems. To simplify the problem, the weight dominance of discs has been assumed. Also the coupling considered in the problem is of flexible type. Misalignment in coupled rotors has been reported in literature to produce all harmonics both odd and even (...−2, −1, 0, 1, 2...) on either side of full spectrum. A suitable coupling excitation function has been chosen so that the response yields all the harmonics in spectrum. The numerical simulation has been performed in MATLAB/SIMULINK™ to generate the responses in time domain. Though AMB is incorporated in the system for vibration attenuation, the emphasis of the present paper shall be to demonstrate the interplay between unbalance and misalignment in flexibly coupled rotor systems.
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Yan, Zhou, Yan Xunshi, Mo Ni, Yang Guojun, and Shi Zhengang. "The Electro Magnetic Compatibility Tests for the AMB System on HTR-10GT." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-66350.
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With more and more widely used in the industrial field, Active Magnetic Bearings (AMB) have bigger challenge, such as the size and the load capacity are larger than before. In order to increase the reliability of the whole system, a lot of aspects have to be improved to adapt some special industrial requirements. Just like the 10MW high temperature gas-cooled test module reactor (HTR-10GT) with the core made of spherical fuel elements, which was designed and constructed by the Institute of Nuclear and New Energy Technology of Tsinghua University in China, take the AMB as the support bearings. HTR-10GT is the reactor with 3.5 meter long rotor, 230mm diameter, and 15000rpm Rated speed. Since there are some difficulties in HTR-10GT including the blade stages, small gap and so on, the high precision control on magnetic bearing is required very much. Once any part in the system is out of work, the rotor would happen to vibrate, which will lead to turbine blades scraping. The consequences could be disastrous especially when the system is in full power at the rated speed [1]. As you know, the electronic control system is the weakest point in AMB, both in operating site and the control room. Therefore, before engineering applications, the electronic control system must be tested for Electromagnetic Compatibility (EMC). Based on the experimental results, some design would be optimized, to improve anti-interference capability to meet the requirements of HTR-10GT. This paper describes the testing process and gives some solutions for EMC problems during the Electro Magnetic Susceptibility (EMS) test, such as the grounding, cable, wiring, filtering etc. These methods are the fundamental basis for reducing interference and improving the reliability of AMB in the HTR-10GT.
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Wizinowich, P., D. S. Acton, A. Gleckler, T. Gregory, P. Stomski, K. Avicola, J. Brase, H. Friedman, D. Gavel, and C. Max. "W.M. Keck Observatory Adaptive Optics Facility." In Adaptive Optics. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/adop.1996.amb.1.
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The W.M. Keck Observatory, in collaboration with Lawrence Livermore National Laboratory (LLNL), is currently in the critical design phase of a natural guide star (NGS) and single laser guide star (LGS) adaptive optics (AO) user facility for the Nasmyth platform of the Keck II 10-m telescope.1 Two science instruments will accompany the AO facility: a near infrared camera (NIRC-2) being built at Caltech, and a near infrared spectrometer (NIRSPEC) being built at UCLA. NASA is planning to fund an interferometer between the Keck telescopes which will require a second NGS AO facility on Keck I.
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Zhang, Wei, Ming-Hui Yao, Xue-Ping Zhan, and Li-Lai Bai. "Multi-Pulse Chaotic Motions of a Rotor-Active Magnetic Bearing With Time-Varying Stiffness." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84676.
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In this paper, we investigate the Shilnikov type multi-pulse chaotic dynamics for a rotor-active magnetic bearings (AMB) system with 8-pole legs and the time-varying stiffness. The stiffness in the AMB is considered as the time varying in a periodic form. The dimensionless equation of motion for the rotor-AMB system with the time-varying stiffness in the horizontal and vertical directions is a two-degree-of-freedom nonlinear system with quadratic and cubic nonlinearities and parametric excitation. The asymptotic perturbation method is used to obtain the averaged equations in the case of primary parametric resonance and 1/2 subharmonic resonance. It is found from the numerical results that there are the phenomena of the Shilnikov type multi-pulse chaotic motions for the rotor-AMB system. A new jumping phenomenon is discovered in the rotor-AMB system with the time-varying stiffness.
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Du, Guowei, Jinpeng Yu, Hong Wang, and Lei Zhao. "The Influence of Thermal Deformation on the Dynamic Characteristics of AMB Rotor of HTR-PM Helium Blower." In 2018 26th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icone26-81132.
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Helium blower is the core component of high temperature gas cooled reactor, which rotor is supported by active magnetic bearings (AMBs). The special advantage of AMB is that there is no contact between bearing and rotor, and this permits operation with small friction, long service life, no lubrication system, and no pollution to the helium environment. [1–3] Helium blower rotor is mainly composed of rotating shaft, impeller, motor, cooling blower and so on, which runs in an uneven temperature field that the impeller runs in a helium chamber of 250 degrees centigrade, and the motor housing’s outer surface temperature is 65 degrees centigrade. The temperature rises from standstill to stable operation will cause the thermal deformation of rotor and bearing, leading to the change of gap between rotor and bearing, which will lead to the change of electromagnetic force of AMB. The electromagnetic force determines the bearing stiffness and bearing damping of the AMB, so the change of temperature is the most important to the stiffness and damping of the AMB, which can affect the dynamic characteristics of the rotor. Through finite element method (FEM) to calculate the temperature field and displacement field of helium blower, the change of the gap of AMB and rotor is calculated. The rotor radial displacement orbits are obtained through numerical simulation, which are affected by thermal deformation. Finally, the results of numerical simulation are verified by experiments. The simulation and experiments both show that temperature rise can increase the vibration amplitude of rotor, so the influence of thermal deformation should be considered when designing the active magnetic bearings.
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Wu, Ruiqin, Wei Zhang, and Ming Hui Yao. "Nonlinear Vibration of a Rotor-Active Magnetic Bearing System With 16-Pole Legs." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-67103.
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In this paper, the nonlinear dynamics of a rotor-active magnetic bearing system with 16-pole legs and the time varying stiffness is investigated. The magnetic forces are obtained through an electromagnetic theory. The motion governing equation is derived by using Newton law. The resulting dimensionless equation of motion for the rotor-AMB system with 16-pole legs and the time varying stiffness is presented with the two-degree-of-freedom system including parametric excitation, the quadratic and cubic nonlinearities. The averaged equations of the rotor-AMB system are obtained by using the method of multiple scales under the case of the primary parametric resonance and 1/2 sub-harmonic resonance. The numerical results show that there exist the periodic, quasi-periodic and chaotic motions in the rotor-active magnetic bearing system. Since the weight of the rotor effect the system, it is also found that there are the different shapes of motion on the two directions of the rotor-AMB system. The parametric excitation, or the time-varying stiffness produced by the PD controller has great impact on the system. Thus, the complicated dynamical response in the rotor-AMB system can be controlled through adjusting the parametric excitation.
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Parfenov, Vadim A., and Sergei N. Rodin. "Nd:YAG Laser Beam Pointing Stability and Artificial Guide Star Generation." In Adaptive Optics. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/adop.1996.amb.26.
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Laser beam pointing instability is one of the most actual problem at the artificial guide stars generation, because high angular stability (~1…2 arcsec) of laser beacons is required for atmosphreric compensation with adaptive optics. In our work we investigated the beam pointing stability of frequency-doubled Nd:YAG lasers generating at the wavelength of 532 nm. Such lasers may be used for guide stars generation by Rayleigh optical scattering by air molecules in the stratosphere [1].
Reports on the topic "Amb a 1"
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Miller, Mark Alan. AMF 1 Site Science. Office of Scientific and Technical Information (OSTI), August 2016. http://dx.doi.org/10.2172/1297867.
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Melidis, Konstantin, and Markus Gruber. Begleitende Evaluierung IWB/EFRE AT 2014-20. Leistungspaket 1: Prioritätsachse 1 – Forschung, technologische Entwicklung und Innovation. Endbericht. Convelop gmbh, February 2022. http://dx.doi.org/10.22163/fteval.2022.582.
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Die Geschäftsstelle der Österreichischen Raumordnungskonferenz (ÖROK GSt.) hat als Verwaltungsbehörde des österreichischen IWB/EFRE -Programms die Durchführung einer begleitenden Evaluierung des Programms beauftragt, die mit Zuschlagserteilung der Bundesbeschaffung GmbH vom 07.12.2017 an ein Konsortium bestehend aus ÖIR, convelop, KMUFA, ÖAR, ÖGUT sowie Spatial Foresight ging. Die Evaluierung wird in mehreren Leistungspaketen bearbeitet, die sich im Wesentlichen auf die Prioritätsachsen des Programms beziehen, ergänzt um Evaluierungen zu den Bereichen „Governance“, „Kommunikation“ und „Querschnittsthemen“. Die gegenständliche Evaluierung ist ein Bestandteil dieser begleitenden Evaluierung und befasst sich im Kern mit den Maßnahmen der Priorität 1 „Stärkung der regionalen Wettbewerbsfähigkeit durch Forschung, technologische Entwicklung und Innovation“, ergänzt um die Maßnahme 15 „F&I in CO2-Reduktionstechnologien“ (P3) sowie die Maßnahmen 16 „F&T-Infrastruktur (Wien)“ und 17 „Innovationsdienstleistungen (Wien)“ (beide PA4). Mit 226,4 Mio. € decken die behandelten Maßnahmen 42% der EFRE-Mittel des Gesamtprogramms ab. Die Evaluierung zeichnet insgesamt ein überwiegend positives Bild der FTI-Förderung im EFRE, das es gilt, auch in Zukunft aufrechtzuerhalten. Die Empfehlungen der FTI-Evaluierung zielen vor allem auf eine noch klarere Konzeption und Darstellung von FTI-Maßnahmen mit grundsätzlich unterschiedlichen Wirkungslogiken und eine Weiterführung bestehender Bemühungen zur Harmonisierung regional unterschiedlicher Abwicklungsmodi innerhalb dieser Maßnahmen ab. Daneben sollte der Anspruch der Anwendungsorientierung im Lichte der stark wahrgenommenen Grundlagenorientierung in der Praxis reflektiert werden. Auch im Bereich der Datenerfassung und -qualitätsicherung wurden Ansatzpunkte für Verbesserungen aufgezeigt.
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