Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
1.
Int J Mol Sci ; 22(14)2021 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-34298941

RESUMO

Clinical research aiming at objectively identifying and characterizing diseases via clinical observations and biological and radiological findings is a critical initial research step when establishing objective diagnostic criteria and treatments. Failure to first define such diagnostic criteria may lead research on pathogenesis and etiology to serious confounding biases and erroneous medical interpretations. This is particularly the case for electrohypersensitivity (EHS) and more particularly for the so-called "provocation tests", which do not investigate the causal origin of EHS but rather the EHS-associated particular environmental intolerance state with hypersensitivity to man-made electromagnetic fields (EMF). However, because those tests depend on multiple EMF-associated physical and biological parameters and have been conducted in patients without having first defined EHS objectively and/or endpoints adequately, they cannot presently be considered to be valid pathogenesis research methodologies. Consequently, the negative results obtained by these tests do not preclude a role of EMF exposure as a symptomatic trigger in EHS patients. Moreover, there is no proof that EHS symptoms or EHS itself are caused by psychosomatic or nocebo effects. This international consensus report pleads for the acknowledgement of EHS as a distinct neuropathological disorder and for its inclusion in the WHO International Classification of Diseases.


Assuntos
Biomarcadores/metabolismo , Hipersensibilidade/metabolismo , Sensibilidade Química Múltipla/metabolismo , Animais , Consenso , Diagnóstico por Imagem/métodos , Testes Diagnósticos de Rotina/métodos , Campos Eletromagnéticos , Humanos , Doenças do Sistema Nervoso/metabolismo
2.
Electromagn Biol Med ; 40(3): 393-407, 2021 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-33687298

RESUMO

This study was designed to investigate the possible effects of exposure to mobile phone base station (MPBS) emits 1800-MHz RF-EMR on some oxidative stress parameters in the brain, heart, kidney and liver of Swiss albino mice under exposures below thermal levels. Mice were randomly assigned to three experimental groups which were exposed to RF-EMR for 6 hr/day, 12 hr/day and 24 hr/day for 45 consecutive days, respectively, and a control group. The glutathione (GSH) levels and activities of glutathione-s-transferase (GST) and superoxide dismutase (SOD) were significantly reduced in mice brain after exposure to RF-EMR for 12 hr and 24 hr per day. Exposure of mice to RF-EMR for 12 hr and 24 hr per day also led to a significant increase in malondialdehyde (an index of lipid peroxidation) levels in mice brain. On the contrary, exposures used in this study did not induce any significant change in various oxidative stress-related parameters in the heart, kidney and liver of mice. Our findings showed no significant variations in the activities of aspartate amino-transferase (AST), alanine amino-transferase (ALT), and on the level of creatinine (CRE) in the exposed mice. This study also revealed a decrease in RBC count with an increase in WBC count in mice subjected to 12 hr/day and 24 hr/day exposures. Exposure to RF-EMR from MPBS may cause adverse effects in mice brain by inducing oxidative stress arising from the generation of reactive oxygen species (ROS) as indicated by enhanced lipid peroxidation, and reduced levels and activities of antioxidants.


Assuntos
Telefone Celular , Campos Eletromagnéticos , Animais , Antioxidantes , Radiação Eletromagnética , Homeostase , Peroxidação de Lipídeos , Camundongos , Estresse Oxidativo
5.
Radiat Prot Dosimetry ; 178(3): 288-291, 2018 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-28981801
8.
Hepatol Int ; 7(2): 516-23, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26201783

RESUMO

BACKGROUND: Chronic hepatitis C (CHC) infection is associated with insulin resistance and with oxidative stress, but the relationship between the two has not been thoroughly examined. PURPOSE: To evaluate the association between insulin resistance and oxidative stress in CHC patients. METHOD: In 115 CHC patients (68 with genotype 1 and 47 with genotype 3), the relationship between the serum concentration of malondialdehyde (MDA), a marker of oxidative stress and insulin resistance as defined by the homeostasis model (HOMA-IR) was examined. RESULTS: There was no significant difference in MDA levels between genotype 1- and genotype 3-infected subjects (12.882 vs. 12.426 ng/mL, p = 0.2). By univariate analysis, factors associated with HOMA-IR in both genotypes were oxidative stress as measured by MDA (p = 0.002), body mass index (BMI), portal activity, and fibrosis. Genotype-specific differences in HOMA-IR association were steatosis and triglycerides (TG) for genotype 1, and age and glutathione (GSH) for genotype 3. In a stepwise multiple linear regression analysis in both genotypes, MDA was a significant and independent predictor of HOMA-IR (p = 0.04). As expected, BMI and fibrosis were likewise independently correlated to HOMA-IR. In addition, MDA levels were higher (p < 0.001) and GSH levels were lower (p = 0.023) in insulin-resistant subjects compared to their insulin-sensitive counterparts. CONCLUSIONS: It is concluded that in CHC, oxidative stress is an independent predictor of HOMA-IR, irrespective of virus genotype. Further studies on the role of oxidative stress in the development of insulin resistance in CHC are warranted.

9.
Hepatology ; 46(1): 66-73, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17596870

RESUMO

UNLABELLED: The role of tumor necrosis factor alpha, interleukin 6, leptin, and adiponectin in the pathogenesis of hepatitis C virus (HCV)-associated insulin resistance (IR) remains controversial. We tested the hypothesis that these adipocytokines contribute to chronic HCV-associated IR and liver injury by first comparing their serum levels and homeostasis model assessment of insulin resistance (HOMA-IR) in 154 untreated, non-diabetic, HCV-infected male subjects with fibrosis stage 0-2, to that in 75 healthy volunteers matched for age, body mass index (BMI), and waist-hip ratio (WHR). We next examined whether the adipocytokine levels were associated with the extent of hepatic steatosis, portal/periportal inflammation and fibrosis in our total cohort of 240 HCV-infected male subjects. Significantly higher levels of HOMA-IR (2.12 versus 1.63, P = 0.01), TNFalpha (1.28 versus 0.60 pg/ml, P < 0.001) and IL6 (2.42 versus 1.15 pg/ml, P = 0.001) were noted in the HCV cohort compared with healthy controls respectively, but there were no significant differences in leptin and adiponectin concentrations. By multiple linear regression, independent predictors of HOMA-IR included the body mass index, and the serum levels of leptin (positive correlation) and adiponectin (negative correlation), but not that of TNFalpha and IL6. Only TNFalpha levels were correlated with the extent of histological injury (portal/periportal inflammation, P = 0.02). CONCLUSION: Whereas leptin and adiponectin contribute to IR, none of the adipocytokines accounted for the elevated IR in HCV-infected subjects. The adipocytokines were not associated with histological features of chronic HCV infection except for TNFalpha which correlated with portal/periportal inflammation. HCV-associated IR is most likely an adipocytokine-independent effect of the virus to modulate insulin sensitivity.


Assuntos
Adiponectina/fisiologia , Hepatite C Crônica/fisiopatologia , Resistência à Insulina , Interleucina-6/fisiologia , Leptina/fisiologia , Cirrose Hepática/virologia , Fígado/patologia , Fator de Necrose Tumoral alfa/fisiologia , Adulto , Biópsia , Genótipo , Hepacivirus/genética , Hepatite C Crônica/patologia , Humanos , Fígado/virologia , Cirrose Hepática/patologia , Cirrose Hepática/fisiopatologia , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Valores de Referência , Carga Viral
10.
Liver Int ; 25(3): 518-26, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15910488

RESUMO

BACKGROUND: This study addressed the suggested association between levels of the antioxidants glutathione (GSH), vitamin C and vitamin E in peripheral blood and the histological activity and fibrosis stage in chronic hepatitis C (CHC). We then determined whether regular antioxidant supplementation influenced these antioxidant levels or disease severity. METHODS: Clinical, biochemical, histological and demographic data were collected from 247 CHC patients at the time of liver biopsy. Whole blood total GSH, plasma vitamin C and E were assessed by high-performance liquid chromatography. Statistical analyses were performed to test for associations between the variables and to identify independent predictors for hepatic necroinflammatory and fibrosis scores. RESULTS: GSH and vitamin C, but not vitamin E correlated with both portal/periportal activity (r = -0.19, P = 0.004; r = -0.19, P = 0.009 respectively) and fibrosis stage (r = -0.18, P = 0.007; r = -0.18, P = 0.009 respectively). GSH was an independent negative predictor of portal/periportal inflammation (P = 0.02) and fibrosis (P = 0.01). Vitamin C was an independent negative predictor of fibrosis stage (P = 0.02). Antioxidant intake was associated with higher vitamin C (P < 0.0001) and vitamin E (P = 0.005) levels, but not GSH. CONCLUSIONS: Whole blood GSH and plasma vitamin C are negatively associated with hepatic portal/periportal inflammation and fibrosis stage in CHC. Controlled intervention studies with vitamin C and agents that boost endogenous GSH levels are warranted.


Assuntos
Antioxidantes/metabolismo , Hepatite C Crônica/metabolismo , Cirrose Hepática/metabolismo , Adolescente , Adulto , Idoso , Antioxidantes/administração & dosagem , Ácido Ascórbico/sangue , Biomarcadores/sangue , Biópsia , Estudos de Coortes , Suplementos Nutricionais , Feminino , Glutationa/sangue , Hepatite C Crônica/patologia , Hepatite C Crônica/virologia , Humanos , Cirrose Hepática/patologia , Cirrose Hepática/virologia , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Índice de Gravidade de Doença , Carga Viral , Vitamina E/sangue
11.
Hepatology ; 39(5): 1239-47, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15122752

RESUMO

We sought to develop a clinically useful index comprising standard and physiologically relevant variables to predict the probability of significant hepatic fibrosis in subjects with chronic hepatitis C virus (HCV) infection. Fibrosis was graded as mild (stages F0 or F1) or significant (stages F2-F4). Thirty-five clinical and laboratory parameters were analyzed initially in 176 patients with detectable HCV RNA to derive a fibrosis probability index (FPI) to predict significant fibrosis. This index then was validated in a second group of 126 subjects. Among 18 variables associated with severe fibrosis on univariate analysis, multiple logistic regression analysis identified age, aspartate aminotransferase (AST), total cholesterol level, insulin resistance (by homeostasis model), and past alcohol intake as independent predictors of significant fibrosis. The area under the receiver operating characteristic (ROC) curves was 0.84 for the initial cohort and 0.77 for the validation cohort. In the initial cohort, the sensitivity of the FPI based on these five predictors was 96%, and the negative predictive value was 93% at a score of >/=0.2. At scores >/=0.8, the FPI was 94% specific and had a positive predictive value of 87%. In conclusion, an FPI using routinely assessed markers and incorporating a measure of insulin resistance can reliably predict the probability of significant hepatic fibrosis in most patients with chronic HCV infection. Such an index should prove useful to guide decision making regarding the need for liver biopsy, and potentially for avoiding or deferring biopsy in a large proportion of patients with mild liver disease.


Assuntos
Hepatite C Crônica/diagnóstico , Resistência à Insulina , Cirrose Hepática/diagnóstico , Índice de Gravidade de Doença , Adulto , Biomarcadores , Estudos de Coortes , Feminino , Hepatite C Crônica/epidemiologia , Humanos , Cirrose Hepática/epidemiologia , Cirrose Hepática/virologia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Prevalência , Probabilidade , Reprodutibilidade dos Testes , Fatores de Risco , Sensibilidade e Especificidade
12.
Gastroenterology ; 125(6): 1695-704, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14724822

RESUMO

BACKGROUND & AIMS: Chronic hepatitis C virus infection is associated with an increased prevalence of type 2 diabetes. We hypothesized that virus-induced insulin resistance may be a mechanism for fibrogenesis in chronic hepatitis C virus infection. METHODS: In 260 hepatitis C virus-infected subjects, we examined the relationship between histological findings and anthropometric and biochemical data, including insulin resistance determined by the homeostasis model assessment (HOMA-IR). We also compared fasting serum insulin, C peptide, and HOMA-IR levels between the subset of 121 hepatitis C virus patients with stage 0 or 1 hepatic fibrosis and 137 healthy volunteers matched by sex, body mass index, and waist-hip ratio. RESULTS: Hepatitis C virus-infected subjects with stage 0 or 1 hepatic fibrosis had higher levels of insulin, C peptide, and HOMA-IR (all P < or = 0.01) compared with matched healthy controls. In the 250 hepatitis C virus patients (fibrosis stage 0 to 4), viral genotype and portal, but not lobular, inflammation were univariate predictors of HOMA-IR. By multiple linear regression analysis, independent predictors of HOMA-IR included body mass index (P < 0.001), previous failed antiviral treatment (P < 0.001), portal inflammatory grade (P < 0.001), and genotype 3 status (P = 0.01). Genotype 3 had significantly lower HOMA-IR than other genotypes (which were comparable when adjusted for effects of the remaining independent predictors). HOMA-IR was an independent predictor for the degree of fibrosis (P < 0.001) and the rate of fibrosis progression (P = 0.03). CONCLUSIONS: Hepatitis C virus may induce insulin resistance irrespective of the severity of liver disease, and this effect seems to be genotype specific. Further, our findings support the hypothesis that insulin resistance may contribute to fibrotic progression in chronic hepatitis C virus infection.


Assuntos
Hepatite C Crônica/complicações , Resistência à Insulina , Cirrose Hepática/etiologia , Adolescente , Adulto , Idoso , Biópsia , Progressão da Doença , Fígado Gorduroso/etiologia , Feminino , Genótipo , Humanos , Fígado/patologia , Masculino , Pessoa de Meia-Idade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA