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1.
Eur Cardiol ; 19: e05, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38983579

RESUMO

Background: AF is a global health concern, with systemic complications including renal dysfunction. This systematic review and meta-analysis compares the effects of rivaroxaban, a Factor Xa inhibitor, and vitamin K antagonists (VKAs) on renal outcomes in AF patients. Methods: The study protocol is registered in PROSPERO (ID: CRD42023462756). We systematically searched the PubMed, Embase and Cochrane Library databases from 1 January 2017 to 30 June 2023 for real-world studies comparing the effects of rivaroxaban and VKAs on renal outcomes in AF patients, including acute kidney injury, a .30% decrease in estimated glomerular filtration rate, doubling of serum creatinine and worsening renal function. Subgroup analyses targeted diabetes, pre-existing kidney disease, the elderly (age .65 years) and Asian populations. The risk of bias was assessed used the Robins-I tool. HRs and 95% CIs were synthesised through a random-effects model. Two sensitivity analyses were performed, using a fixed-effects model and excluding conference abstracts. Results: We identified 1,666 records. After screening, 14 studies comparing rivaroxaban and VKAs were included. Rivaroxaban exhibited superiority over VKAs in preventing: acute kidney injury (HR 0.68; 95% CI [0.61.0.77]; p<0.00001); a .30% decrease in estimated glomerular filtration rate (HR 0.71; 95% CI [0.60.0.84]; p<0.0001); doubling of serum creatinine (HR 0.50; 95% CI [0.36.0.70]; p<0.0001); and worsening renal function (HR 0.56; 95% CI [0.45.0.69]; p<0.00001). Subgroup and sensitivity analyses consistently confirmed rivaroxaban's favourable effects on renal outcomes in diabetes, pre-existing kidney disease, the elderly and Asian populations. Conclusion: Our findings support the preference of rivaroxaban over VKAs for renal outcomes in AF. The findings endorse rivaroxaban as the preferred anticoagulant to mitigate renal complications, offering clinicians valuable insights for tailored strategies.

2.
J Med Case Rep ; 18(1): 49, 2024 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-38336791

RESUMO

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC), or more recently known as arrhythmogenic cardiomyopathy (ACM), is an heritable disorder of the myocardium characterized by progressive fibrofatty replacement the heart muscle and risk of ventricular arrhythmias and sudden cardiac death (SCD). We report a case study to demonstrate the role of gene mutation detection in risk stratification for primary prevention of SCD in a young patient diagnosed with ARVC. CASE PRESENTATION: A 15-year-old Asian (Vietnamese) male patient with no history of documented tachyarrhythmia or syncope and a family history of potential SCD was admitted due to palpitations. Clinical findings and work-up including cardiac magnetic resonance imaging (MRI) were highly suggestive of ARVC. Gene sequencing was performed for SCD risk stratification, during which PKP2 gene mutation was found. Based on the individualized risk stratification, an ICD was implanted for primary prevention of SCD. At 6 months post ICD implantation, the device detected and successfully delivered an appropriate shock to terminate an episode of potentially fatal ventricular arrhythmia. ICD implantation was therefore proven to be appropriate in this patient. CONCLUSIONS: While gene mutations are known to be an important factor in the diagnosis of ARVC according to the 2010 Task Force Criteria and recent clinical guidelines, their role in risk stratification of SCD remains controversial. Our case demonstrated that when used with other clinical factors and family history, this information could be helpful in identifying appropriate indication for ICD implantation.


Assuntos
Displasia Arritmogênica Ventricular Direita , Humanos , Masculino , Adolescente , Displasia Arritmogênica Ventricular Direita/complicações , Displasia Arritmogênica Ventricular Direita/diagnóstico , Displasia Arritmogênica Ventricular Direita/genética , Prognóstico , Morte Súbita Cardíaca/etiologia , Morte Súbita Cardíaca/prevenção & controle , Eletrocardiografia , Mutação
4.
Bull Cancer ; 109(2): 170-184, 2022 Feb.
Artigo em Francês | MEDLINE | ID: mdl-35034786

RESUMO

Technological advances, in particular the development of high-throughput sequencing, have led to the emergence of a new generation of molecular biomarkers for tumors. These new tools have profoundly changed therapeutic management in oncology, with increasingly precise molecular characterization of tumors leading to increasingly personalized therapeutic targeting. Detection of circulating tumor cells and/or circulating tumor DNA in blood samples -so-called 'liquid biopsies'- can now provide a genetic snapshot of the patient's tumor through an alternative and less invasive procedure than biopsy of the tumor tissue itself. This procedure for characterizing and monitoring the disease in real time facilitates the search for possible relapses, the emergence of resistance, or emergence of a new therapeutic target. In the long term, it might also provide a means of early detection of cancer. These new approaches require the treatment of ever-increasing amounts of clinical data, notably, with the goal of calculating composite clinical-biological predictive scores. The use of artificial intelligence will be unavoidable in this domain, but it raises ethical questions and implications for the health-care system that will have to be addressed.


Assuntos
Inteligência Artificial/tendências , Biomarcadores Tumorais/sangue , Biópsia Líquida , Oncologia/tendências , Neoplasias/sangue , Medicina de Precisão/tendências , Inteligência Artificial/ética , DNA Tumoral Circulante/sangue , Gerenciamento de Dados , Detecção Precoce de Câncer/métodos , Sequenciamento de Nucleotídeos em Larga Escala/tendências , Humanos , Imunoterapia , Biópsia Líquida/métodos , Oncologia/métodos , MicroRNAs/sangue , Recidiva Local de Neoplasia/sangue , Recidiva Local de Neoplasia/diagnóstico , Neoplasias/genética , Neoplasias/terapia , Células Neoplásicas Circulantes
5.
Bull Cancer ; 109(2): 151-169, 2022 Feb.
Artigo em Francês | MEDLINE | ID: mdl-35012767

RESUMO

In oncology, the identification of targets that correlate with a type of cancer has led to a profound change in the notion of "tumor markers". Technological advances, in particular the development of high-throughput sequencing, have led to the emergence of a new generation of molecular biomarkers for tumors. Despite their limited utility for screening and diagnosis, conventional tumor markers remain interesting for evaluation of prognoses, the choice and optimization of treatments, as well as for monitoring the effectiveness of those treatments. In this article, we revisit the conventional serum markers that are enjoying a 'come back' thanks to the development of high-performance scores based on biological, cytological, clinical, or radiological criteria.


Assuntos
Biomarcadores Tumorais/sangue , Oncologia/métodos , Proteínas de Neoplasias/sangue , Neoplasias/sangue , Medicina de Precisão/métodos , França , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Recidiva Local de Neoplasia/sangue , Recidiva Local de Neoplasia/diagnóstico , Neoplasias/diagnóstico , Neoplasias/imunologia , Neoplasias/terapia , Especificidade de Órgãos , Valor Preditivo dos Testes , Prognóstico , Reprodutibilidade dos Testes , Resultado do Tratamento
6.
Anaesth Crit Care Pain Med ; 40(3): 100830, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33744493

RESUMO

BACKGROUND: Mental health and well-being is a significant problem for medical students in training. In this study, we aim to estimate the prevalence of anxiety and depressive symptoms, burnout and psychosocial distress in French anaesthesia and intensive care residents. METHODS: A national online observational study used validated questionnaires (Hospital Anxiety and Depression Scale (HADS), Copenhagen Burnout Inventory (CBI), Perceived Stress Scale (PSS) and work-related questions (work-hours per week, night shift per month, safety rest after night shift, average time to start and end work, break time and time for lunch) to assess mental health and well-being of French residents in anaesthesia and intensive care. RESULTS: We obtained 519 answers (22.5% of 2302 students), 55% of respondents working in anaesthesia, 41% in intensive care at the time of study. Residents describe certain symptomatology in anxiety (19.8%) and depressive symptoms (7.8%). PSS identifies a perceived high stress (score > 27) for 55.7% of the subjects. The CBI questionnaire identifies 205 (38.9%) residents undergoing burnout, 80.7% working more than 48 h per week and 39.1% more than 60 h. The duration of work per week (> 50 h), gender (female) and on-going training in intensive care are independent risk factors of psychological suffering. Lifestyle and level of training are not statistically identified risk factors. CONCLUSION: This first online survey of French anaesthesia and intensive care residents reveals a significant frequency of anxiety and depressive symptoms, burnout and a link to potential targets of improvement in work conditions mainly related to the number of work hours per week.


Assuntos
Anestesia , Esgotamento Profissional , Internato e Residência , Ansiedade/epidemiologia , Esgotamento Profissional/epidemiologia , Cuidados Críticos , Depressão/epidemiologia , Feminino , Humanos , Inquéritos e Questionários
7.
Int J Med Inform ; 141: 104203, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32485553

RESUMO

OBJECTIVE: This article introduces SCALPEL3 (Scalable Pipeline for Health Data), a scalable open-source framework for studies involving Large Observational Databases (LODs). It focuses on scalable medical concept extraction, easy interactive analysis, and helpers for data flow analysis to accelerate studies performed on LODs. MATERIALS AND METHODS: Inspired from web analytics, SCALPEL3 relies on distributed computing, data denormalization and columnar storage. It was compared to the existing SAS-Oracle SNDS infrastructure by performing several queries on a dataset containing a three years-long history of healthcare claims of 13.7 million patients. RESULTS AND DISCUSSION: SCALPEL3 horizontal scalability allows handling large tasks quicker than the existing infrastructure while it has comparable performance when using only a few executors. SCALPEL3 provides a sharp interactive control of data processing through legible code, which helps to build studies with full reproducibility, leading to improved maintainability and audit of studies performed on LODs. CONCLUSION: SCALPEL3 makes studies based on SNDS much easier and more scalable than the existing framework [1]. It is now used at the agency collecting SNDS data, at the French Ministry of Health and soon at the National Health Data Hub in France [2].


Assuntos
Atenção à Saúde , Bases de Dados Factuais , França , Humanos , Reprodutibilidade dos Testes
8.
BMC Med ; 18(1): 107, 2020 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-32423410

RESUMO

BACKGROUND: Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE) risk score is the only currently available midlife risk score for dementia. We compared CAIDE to Framingham cardiovascular Risk Score (FRS) and FINDRISC diabetes score as predictors of dementia and assessed the role of age in their associations with dementia. We then examined whether these risk scores were associated with dementia in those free of cardiometabolic disease over the follow-up. METHODS: A total of 7553 participants, 39-63 years in 1991-1993, were followed for cardiometabolic disease (diabetes, coronary heart disease, stroke) and dementia (N = 318) for a mean 23.5 years. Cox regression was used to model associations of age at baseline, CAIDE, FRS, and FINDRISC risk scores with incident dementia. Predictive performance was assessed using Royston's R2, Harrell's C-index, Akaike's information criterion (AIC), the Greenwood-Nam-D'Agostino (GND) test, and calibration-in-the-large. Age effect was also assessed by stratifying analyses by age group. Finally, in multistate models, we examined whether cardiometabolic risk scores were associated with incidence of dementia in persons who remained free of cardiometabolic disease over the follow-up. RESULTS: Among the risk scores, the predictive performance of CAIDE (C-statistic = 0.714; 95% CI 0.690-0.739) and FRS (C-statistic = 0.719; 95% CI 0.693-0.745) scores was better than FINDRISC (C-statistic = 0.630; 95% CI 0.602-0.659); p < 0.001), AIC difference > 3; R2 32.5%, 32.0%, and 12.5%, respectively. When the effect of age in these risk scores was removed by drawing data on risk scores at age 55, 60, and 65 years, the association with dementia in all age groups remained for FRS and FINDRISC, but not for CAIDE. Only FRS at age 55 was associated with dementia in persons who remained free of cardiometabolic diseases prior to dementia diagnosis while no such association was observed at older ages for any risk score. CONCLUSIONS: Our analyses of CAIDE, FRS, and FINDRISC show the FRS in midlife to predict dementia as well as the CAIDE risk score, its predictive value being also evident among individuals who did not develop cardiometabolic events. The importance of age in the predictive performance of all three risk scores highlights the need for the development of multivariable risk scores in midlife for primary prevention of dementia.


Assuntos
Fatores de Risco Cardiometabólico , Demência/diagnóstico , Adulto , Envelhecimento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Medição de Risco
9.
Heliyon ; 6(2): e03383, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32072063

RESUMO

BACKGROUND: Hypertension (HTN) significantly contributes to global disease burden, and its prevalence varies amongst different countries and regions. This work is aimed to characterize the hypertensive prevalence and identify risk factors for HTN among the residents in five locations (four communes and one town) of Moc Chau district (Son La province, Vietnam). METHODS: A cross-sectional study with a cross-sectional methodology was done in selected places from August 2018 to December 2018. We interviewed 197 participants aged equal to or more than 18 years old and measured their blood pressure (BP). Univariate and multivariate logistic regression were applied. RESULTS: The overall HTN prevalence of 30.0% was recorded. The differences of HTN prevalence rates were seen by several characters including age groups (p <0.001), accompanying disease (p <0.001) and alcohol drinking (p <0.05). Factors independently associated with hypertension were age (ORs: 3.1 [1.1-9.1]; 6.1 [1.7-22.3]), much salty consumption (OR: 2.6 [1.1-6.6]), alcohol use (OR: 3.1 [1.2-8.1]), HTN familial history (OR: 4.2 [1.3-13.3]) and at least one suffering disease (OR: 5.2 [2.1-12.7]). CONCLUSIONS: Thus, this study highlighted the high overall HTN prevalence in the Vietnam Northwestern region. Significant differences of HTN rate were observed among several characteristics such as age groups, accompanying disease and alcohol drinking. Age group, much salty consumption, alcohol use, hypertension familial history and at least one suffering disease were risk factors for HTN in study group.

12.
Br J Clin Pharmacol ; 82(5): 1371-1381, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27331367

RESUMO

AIMS: In drug development, the anti-inflammatory properties of new molecules in the lung are currently tested using the inhaled lipopolysaccharide (LPS) model. The total and regional lung bioavailability of inhaled particles depends significantly on their size. The objective of the present study was to compare inflammatory responses in healthy volunteers after the inhalation of LPS of varying droplet size. METHODS: Three nebulizers were characterized by different droplet size distributions [mean mass median aerodynamic diameters: Microcirrus (2.0 µm), MB2 (3.2 µm) and Pari (7.9 µm)]. Participants inhaled three boluses of a 20 µg (technetium 99 m-labelled) solution of LPS, randomly delivered by each nebulizer. We measured the lung deposition of the nebulized LPS by gamma-scintigraphy, while blood and sputum biomarkers were evaluated before and after challenges. RESULTS: MB2 and Pari achieved greater lung deposition than Microcirrus [171.5 (±72.9) and 217.6 (±97.8) counts pixel-1 , respectively, vs. 67.9 (±20.6) counts pixel-1 ; P < 0.01]. MB2 and Pari caused higher levels of blood C-reactive protein and more total cells and neutrophils in sputum compared with Microcirrus (P < 0.05). C-reactive protein levels correlated positively with lung deposition (P < 0.01). CONCLUSIONS: Inhalation of large droplets of LPS gave rise to greater lung deposition and induced a more pronounced systemic and bronchial inflammatory response than small droplets. The systemic inflammatory response correlated with lung deposition. NCT01081392.


Assuntos
Proteína C-Reativa/metabolismo , Inflamação/induzido quimicamente , Lipopolissacarídeos/farmacocinética , Neutrófilos/efeitos dos fármacos , Tamanho da Partícula , Tecnécio/farmacocinética , Administração por Inalação , Adolescente , Adulto , Contagem de Células , Feminino , Voluntários Saudáveis , Humanos , Inflamação/metabolismo , Lipopolissacarídeos/administração & dosagem , Pulmão/metabolismo , Masculino , Pessoa de Meia-Idade , Nebulizadores e Vaporizadores , Cintilografia , Escarro/citologia , Tecnécio/administração & dosagem , Adulto Jovem
13.
Sci Rep ; 6: 18617, 2016 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-26743578

RESUMO

Hypothyroidism due to THRA1 (gene coding for thyroid hormone receptor α1) mutation-mediated Resistance to Thyroid Hormone (RTH) has been recently reported in human and is associated with memory deficits similar to those found in a mouse model for Thra1 mutation mediated RTH (Thra1(+/m) mice). Here, we show that a short-term treatment of Thra1(+/m) mice with GABAA receptor antagonist pentylenetetrazol (PTZ) completely and durably rescues their memory performance. In the CA1 region of the hippocampus, improvement of memory is associated with increased in long-term potentiation (LTP) and an augmentation of density of dendritic spines (DDS) onto the apical dendrites of pyramidal cells reflecting an increase in the local excitatory drive. Unbiased gene profiling analysis of hippocampi of treated Thra1(+/+) and Thra1(+/m) mice were performed two weeks and three months post treatment and identified co-expression modules that include differentially expressed genes related with and predicting higher memory, LTP and DDS in the hippocampi of PTZ-treated animals. We observed that PTZ treatment changed similar sets of genes in both Thra1(+/+) and Thra1(+/m) mice, which are known to be involved in memory consolidation and neurotransmission dynamics and could participate in the persistent effects of PTZ on memory recovery.


Assuntos
Antagonistas de Receptores de GABA-A/farmacologia , Hipotireoidismo/tratamento farmacológico , Transtornos da Memória/tratamento farmacológico , Pentilenotetrazol/farmacologia , Receptores alfa dos Hormônios Tireóideos/genética , Hormônios Tireóideos/genética , Transcriptoma , Animais , Região CA1 Hipocampal/efeitos dos fármacos , Região CA1 Hipocampal/metabolismo , Região CA1 Hipocampal/patologia , Espinhas Dendríticas/efeitos dos fármacos , Modelos Animais de Doenças , Potenciais Pós-Sinápticos Excitadores/efeitos dos fármacos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Hipotireoidismo/complicações , Hipotireoidismo/genética , Hipotireoidismo/metabolismo , Potenciação de Longa Duração/efeitos dos fármacos , Masculino , Transtornos da Memória/complicações , Transtornos da Memória/genética , Transtornos da Memória/metabolismo , Camundongos , Camundongos Transgênicos , Mutação , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Células Piramidais/efeitos dos fármacos , Células Piramidais/metabolismo , Células Piramidais/patologia , Transmissão Sináptica/efeitos dos fármacos , Receptores alfa dos Hormônios Tireóideos/deficiência , Hormônios Tireóideos/metabolismo
14.
BMC Pharmacol Toxicol ; 15: 60, 2014 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-25371053

RESUMO

BACKGROUND: Inhaled endotoxin induces airways'neutrophilia, in human. TNF-a being a key cytokine in the response to endotoxin, the effect of anti-TNF on the endotoxin-induced neutrophilic response was evaluated among healthy volunteers. METHODS: Among a population of 30 healthy subjects, an induced-sputum was collected 2 weeks before, and 24 hours after an inhalation of 20 mcg endotoxin (E. coli 026:B6). Then, the subjects were randomized into 3 parallel groups treated with control, oral methylprednisolone 20 mg/day during 7 days or anti-TNF (adalimumab, Humira®, Abbott) 40 mg s.c.. One week later, an induced-sputum was sampled, 24 hours after an inhalation of endotoxin. RESULTS: After endotoxin inhalation, the number of total cells, neutrophils and macrophages was significantly increased (p <0.001). Compared to the response to endotoxin among the control group, anti-TNF inhibited the endotoxin-induced neutrophil influx, both in relative (51.3 (±6.4)% versus 26.2 (±5.3)%, p <0.002) and in absolute values (1321 (443-3935) cells/mcL versus 247 (68-906) cells/mcL, p <0.02). The endotoxin-induced neutrophilic response was not significantly modified among the control group and oral corticosteroid group. CONCLUSIONS: While oral corticosteroid had no effect, anti-TNF inhibited the neutrophil influx in sputum, induced by inhalation of endotoxin, in human subject. The endotoxin model could be an early predictor of clinical efficacy of novel therapeutics. TRIAL REGISTRATION: ClinicalTrials.gov NCT02252809 (EudraCT2008-005526-37).


Assuntos
Anticorpos Monoclonais Humanizados/farmacologia , Inflamação/imunologia , Neutrófilos/efeitos dos fármacos , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Adalimumab , Administração por Inalação , Adulto , Contagem de Células , Escherichia coli , Feminino , Humanos , Inflamação/induzido quimicamente , Lipopolissacarídeos , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Masculino , Metilprednisolona/farmacologia , Neutrófilos/imunologia , Escarro/citologia
15.
Br J Clin Pharmacol ; 72(6): 912-20, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21595743

RESUMO

AIM: Pharmacological profiling techniques, such as the cantharidin-induced skin blister, may be used to assess the anti-inflammatory properties of novel drugs. However, no data are available on the reproducibility of this technique or on the blocking effect of anti-inflammatory drugs, such as anti-TNF and corticosteroids. METHODS: A group of 30 healthy subjects were randomized into three parallel groups treated with placebo, oral methylprednisolone 20 mg day(-1) for 7 days or anti-tumour necrosis factor (TNF) (adalimumab, Humira®, Abbott) 40 mg s.c. single dose. A first blister was induced at baseline and collected, immediately before the start of treatment and a second blister was obtained 7 days after the start of treatment. The total number of cells, the cell viability and the differential cell count were evaluated by two independent observers, who were blind to treatment. anova was used to compare change from baseline among the three groups before pairwise comparisons. RESULTS: Among the placebo group, there was no significant difference in the total cell count, neutrophils, eosinophils and monocytes between day 1 and day 7. Methylprednisolone inhibited the eosinophil influx in mean % (95% CI) (-1.0 (-1.7, -0.3); P < 0.02) and absolute (P < 0.02) values, while anti-TNF inhibited the neutrophil influx in mean % (95% CI) (-19.3 (-29.5, -9.1); P < 0.01) and absolute (P < 0.05) values. CONCLUSIONS: The cantharidin-induced skin blister is a safe, well tolerated and reproducible procedure. Pre-treatment with anti-TNF or methylprednisolone inhibited the neutrophilic or eosinophilic trafficking, respectively. It could be useful in profiling anti-inflammatory drugs regarding their effects on the cellular inflammatory response.


Assuntos
Anti-Inflamatórios/farmacologia , Vesícula/induzido quimicamente , Cantaridina/toxicidade , Inflamação/induzido quimicamente , Adalimumab , Adulto , Anticorpos Monoclonais Humanizados/farmacologia , Vesícula/tratamento farmacológico , Vesícula/patologia , Eosinófilos/efeitos dos fármacos , Eosinófilos/metabolismo , Feminino , Humanos , Inflamação/tratamento farmacológico , Inflamação/patologia , Irritantes/toxicidade , Masculino , Metilprednisolona/farmacologia , Modelos Biológicos , Neutrófilos/efeitos dos fármacos , Neutrófilos/metabolismo , Reprodutibilidade dos Testes , Pele/patologia , Fator de Necrose Tumoral alfa/antagonistas & inibidores
16.
J Phys Chem B ; 113(17): 5829-36, 2009 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-19341249

RESUMO

Electrotransport of sodium chloride near and through the ASV anion exchange membrane was first investigated. Chronopotentiometric and current-voltage characteristics results have shown that the ASV membrane acts as a totally conducting plane with respect to the transport of NaCl electrolyte. SEM and AFM images contributed to confirm the overall homogeneous surface of the membrane. Further chronopotentiometric studies of the membrane were evaluated in the presence of different alkaline chloride solutions in order to explore the influence of alkali co-ions on the transport phenomena. Membrane characterization led to determine the transport number of chloride counterion in the membrane. It is reported in this work that chronopotentiometry using the Sand equation toward the homogeneous ion exchange membrane is a simple and efficient method for determination of the diffusion coefficient of the electrolytes in the bulk solution. Discussions on the transport properties of the electrolyte solutions in relation with the hydrated ion sizes allowed us to verify the diffusion coefficient of the electrolytes determined by means of chronopotentiometric method.

17.
PLoS One ; 4(3): e5004, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19325915

RESUMO

Mutations in the gene encoding Cu-Zn superoxide dismutase (SOD1) are one of the causes of familial amyotrophic lateral sclerosis (FALS). Fibrillar inclusions containing SOD1 and SOD1 inclusions that bind the amyloid-specific dye thioflavin S have been found in neurons of transgenic mice expressing mutant SOD1. Therefore, the formation of amyloid fibrils from human SOD1 was investigated. When agitated at acidic pH in the presence of low concentrations of guanidine or acetonitrile, metalated SOD1 formed fibrillar material which bound both thioflavin T and Congo red and had circular dichroism and infrared spectra characteristic of amyloid. While metalated SOD1 did not form amyloid-like aggregates at neutral pH, either removing metals from SOD1 with its intramolecular disulfide bond intact or reducing the intramolecular disulfide bond of metalated SOD1 was sufficient to promote formation of these aggregates. SOD1 formed amyloid-like aggregates both with and without intermolecular disulfide bonds, depending on the incubation conditions, and a mutant SOD1 lacking free sulfhydryl groups (AS-SOD1) formed amyloid-like aggregates at neutral pH under reducing conditions. ALS mutations enhanced the ability of disulfide-reduced SOD1 to form amyloid-like aggregates, and apo-AS-SOD1 formed amyloid-like aggregates at pH 7 only when an ALS mutation was also present. These results indicate that some mutations related to ALS promote formation of amyloid-like aggregates by facilitating the loss of metals and/or by making the intramolecular disulfide bond more susceptible to reduction, thus allowing the conversion of SOD1 to a form that aggregates to form resembling amyloid. Furthermore, the occurrence of amyloid-like aggregates per se does not depend on forming intermolecular disulfide bonds, and multiple forms of such aggregates can be produced from SOD1.


Assuntos
Amiloide/metabolismo , Esclerose Lateral Amiotrófica/genética , Metais/metabolismo , Mutação , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismo , Esclerose Lateral Amiotrófica/enzimologia , Dissulfetos/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Multimerização Proteica , Superóxido Dismutase-1
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