The importance of homocysteine levels in the prognosis of patients with chronic renal disease and in hemodialysis patients / Importância dos níveis de homocisteína no prognóstico de pacientes com doença renal crônica e em pacientes em hemodiálise

ABSTRACT Introduction: Homocysteine (Hcy) is one of the metabolites of methionine (Met), an essential diet-derived amino acid. There is a close relationship between high plasma Hcy levels and declining renal function. Plasma and urinary Hcy level has been the target of studies as a biomarker that forecasts poor outcome in renal patients and in hemodialysis patients. This review evaluates the main studies that sought to correlate Hcy and poor prognosis in renal disease as well as the treatments proposed for the reduction of plasma Hcy levels in these patients. Conclusion: Hcy could be an important biomarker of renal disease progression mainly in hemodialysis patients. We emphasize the importance of normalizing plasma levels of this amino acid to ensure a better prognosis in kidney disease.

RESUMO Introdução: A homocisteína (Hcy) é um dos metabólitos da metionina (Met), um aminoácido essencial proveniente da dieta. Existe uma estreita relação entre os altos níveis plasmáticos de Hcy e o declínio da função renal. A Hcy plasmática e urinária tem sido alvo de estudos como um biomarcador capaz de sinalizar o prognóstico em doentes renais e em pacientes em hemodiálise. Esta revisão avalia os principais estudos que buscaram correlacionar a Hcy e o prognóstico da doença renal e descreve os tratamentos propostos para a redução dos níveis plasmáticos de Hcy nesses pacientes. Conclusão: A Hcy pode ser um biomarcador da progressão na doença renal, principalmente em pacientes hemodialíticos. Ressaltamos a importância da normalização dos níveis plasmáticos desse aminoácido para garantir um melhor prognóstico na doença renal.

Evaluation of the performance of tuberculosis control actions and services of the family health strategies / Avaliação do desempenho das ações e serviços de controle da Tuberculose pela estratégia saúde da família

INTRODUCTION: Front of the persistence of tuberculosis in several municipalities in the country, the Ministry of Health (MS) established the National Tuberculosis Control Plan (NTCP), whose goals were to integrate 100% of the Brazilian municipalities in the fight against the disease. OBJECTIVE: To evaluate the performance of tuberculosis (TB) control actions and services of the Family Health Strategies in the city of Salgueiro-PE. METHOD: Cross-sectional, quantitative and descriptive survey study that evaluated health services in the city of Salgueiro-Pe, involving 40 participants. The data were selected through the steps of specific questions for the evaluation of TB, in addition to the questions on the epidemiological situation and the current state of health. In order to know the conditions for the control of TB in the municipality, a script was also elaborated with orientations directed to the manager. RESULTS: The results of our study showed a population aged from 34 to 59 years with a predominance of males (70%) and incomplete elementary school (37.5%). Regarding the place of diagnosis, the hospital had a higher prevalence of cases diagnosed with tuberculosis with 62.5%. 85,0% performed the Directly Observed Treatment. The averages of the evaluated actions showed that the municipality of Salgueiro-PE does not develop actions of health education and active search of symptomatic respiratory patients, The results were favorable only for the accomplishment of sputum bacilloscopy, monthly consultations of control and medical monitoring. CONCLUSION: The results showed weaknesses in the performance of actions and services by the Family Health Strategy in the municipality of Salgueiro, with damage to TB control and treatment.

INTRODUÇÃO: A atenção básica é resultado do desenvolvimento e consolidação do SUS através do programa de Estratégia Saúde da Família. Diante do quadro de persistência da tuberculose em vários municípios do País, o Ministério da Saúde (MS) estabeleceu o Plano Nacional de Controle da Tuberculose (PNCT) cujas metas eram integrar 100% dos municípios brasileiros na luta contra a doença. OBJETIVO: Avaliar o desempenho das ações e serviços de controle da tuberculose (TB) da Estratégia Saúde da Família no município de Salgueiro-PE. MÉTODO: Trata-se de estudo transversal, quantitativo e descritivo de inquérito que avaliou serviços de saúde na cidade de Salgueiro-PE, envolvendo 40 participantes. Os dados foram coletados através de questionário com perguntas específicas para cada componente organizacional essencial da atenção básica para as ações de controle da TB, além de perguntas sobre o perfil do paciente, informações clínicas epidemiológicas e estado atual de saúde. A fim de conhecer as políticas realizadas no controle da TB no município em estudo, foi também elaborado um roteiro com perguntas direcionadas ao gestor. RESULTADOS: Houve predominância do sexo masculino com 28 (70%), com ensino fundamental incompleto 15 (37,5%) e com faixa etária de 34 a 59 anos de idade. Quanto ao local do diagnóstico, o hospital teve maior prevalência de casos diagnosticados com tuberculose com 62,5%, os que realizavam tratamento supervisionado foram 85,0%. As médias das ações avaliadas demonstraram que o município de Salgueiro-PE não desenvolve ações de educação em saúde e busca ativa de sintomáticos respiratórios, obtendo médias favoráveis apenas para realização da baciloscopia de diagnóstico, consultas mensais de controle e acompanhamento medicamentoso. CONCLUSÃO: Houve fragilidades no desempenho das ações e serviços pela estratégia saúde da família no munícipio de Salgueiro, com prejuízos ao controle e ao tratamento, sendo necessário o fortalecimento das ações e serviços no combate à doença.

Basal neutrophil function in human aging: Implications in endothelial cell adhesion.

Much attention has been drawn to the pro-inflammatory condition that accompanies aging. This study compared parameters from non-stimulated neutrophils, obtained from young (18-30 years old [y.o.]) and elderly (65-80 y.o.) human volunteers. Measured as an inflammatory marker, plasmatic concentration of hs-CRP was found higher in elderly individuals. Non-stimulated neutrophil production of ROS and NO was, respectively, 38 and 29% higher for the aged group. From the adhesion molecules evaluated, only CD11b expression was elevated in neutrophils from the aged group, whereas no differences were found for CD11a, CD18, or CD62. A 69% higher non-stimulated in vitro neutrophil/endothelial cell adhesion was observed for neutrophils isolated from elderly donors. Our results suggest that with aging, neutrophils may be constitutively producing more reactive species in closer proximity to endothelial cells of vessel walls, which may both contribute to vascular damage and reflect a neutrophil intracellular disrupted redox balance, altering neutrophil function in aging.

Adhesion molecules in breast carcinoma: a challenge to the pathologist.

The role of adhesion molecules is very important both in the activation of carcinogenesis and in the differentiation of subtypes of breast carcinoma, aiding in diagnosis, prognosis and therapeutic choice in these tumors. Therefore, understanding the functions and interrelationships among these molecules is crucial to the pathologist, who often uses these factors as a resource to differentiate tumors and further classify them according to a molecular point of view. Our goal is to describe the applicability and the difficulties encountered by the pathologist in the diagnosis of breast carcinoma, discussing the most commonly used markers of adhesion in routine analyses.

Plasma levels of E-cadherin and MMP-13 in prostate cancer patients: correlation with PSA, testosterone and pathological parameters.

AIMS AND BACKGROUND: Prostate cancer is the most common malignant tumor in men. Serum prostate-specific antigen (PSA), Gleason score and clinical range at the time of diagnosis are important factors to predict prognosis and outcome after therapy but additional accurate and reliable biomarkers are still wanted. So far, few biomarkers of prostate cancer have been successfully implemented and are being used in clinical practice. However, modifications of E-cadherin and MMP-13 expression are likely to be involved in prostate cancer invasion and thus are potential biomarkers for prognosis. PATIENTS AND METHODS: We analyzed the concentrations of E-cadherin and MMP-13 in plasma of patients with prostate cancer at diagnosis and 3 and 6 months after the beginning of treatment and related these measures to free and total PSA and other clinical features. RESULTS: The concentration of E-cadherin was lower in patients with prostate cancer compared to the control group, but there was no difference in the concentration of MMP-13 between these two groups. During treatment, however, we found no significant differences between the concentrations of MMP-13 and E-cadherin, but we observed a significant positive correlation between total PSA and E-cadherin plasma concentration at the third month of treatment and between total testosterone and MMP-13 plasma concentration before the start of treatment. CONCLUSIONS: The results suggest that these parameters could be used both in the diagnosis and prognosis of prostate cancer.

Adhesion molecules in breast carcinoma: a challenge to the pathologist / Moléculas de adesão no carcinoma mamário: um desafio ao patologista

The role of adhesion molecules is very important both in the activation of carcinogenesis and in the differentiation of subtypes of breast carcinoma, aiding in diagnosis, prognosis and therapeutic choice in these tumors. Therefore, understanding the functions and interrelationships among these molecules is crucial to the pathologist, who often uses these factors as a resource to differentiate tumors and further classify them according to a molecular point of view. Our goal is to describe the applicability and the difficulties encountered by the pathologist in the diagnosis of breast carcinoma, discussing the most commonly used markers of adhesion in routine analyses.

O papel das moléculas de adesão é de suma importância tanto na ativação da carcinogênese quanto na diferenciação dos subtipos de carcinomas mamários, auxiliando no diagnóstico, no prognóstico e na escolha terapêutica nessas neoplasias. Portanto, a compreensão das funções e das inter-relações entre essas moléculas é de suma importância para o patologista, que, muitas vezes, as utiliza como recurso na diferenciação dos tumores e, consequentemente, elas auxiliam em uma posterior classificação do ponto de vista molecular. O objetivo é descrever a aplicabilidade e as dificuldades encontradas pelo médico patologista no diagnóstico de carcinoma mamário, discutindo os marcadores de adesividade mais utilizados na rotina.

Inability of Turbidimetry Method in Detecting Glycated Hemoglobin to Select Diabetes Mellitus Patients According to Their Concentrations of Blood Glucose Levels.

BACKGROUND: Diabetes mellitus is a chronicle illness in which there is a high blood glucose level defined as hyperglycemia, resulted by a deficiency in insulin secretion and/or in its action. Nowadays, it is being seen as a public health problem and is reaching increasing proportions with regard to the appearance of new cases. For diagnosis, sensible and accurate methods should be used to avoid complications of the sickness. The measure of glycated hemoglobin may not be used for diagnosis, but is the reference method to evaluate the grade of glycemic control in the long term, reflecting the blood glucose level in the latest 2-3 months. The aim of this study was to evaluate the grade of concordance between turbidimetry and liquid chromatography methods in the glycated hemoglobin determination and to estimate the sensibility and specificity values of turbidimetry. METHODS: This study included 133 blood samples obtained from patients and healthy donors, ageing between 18 and 80 years with glycemic values between 58 and 473 mg/dl. RESULTS AND CONCLUSION: Turbidimetry is a useful method for determining glycemic levels above 100 and over 200 mg/dl, but does not have the ability to select samples with intermediary blood glucose concentrations.

Systemic chemotherapy interferes in homocysteine metabolism in breast cancer patients.

BACKGROUND: Hyperhomocysteinemia in breast cancer (BC) patients can be a risk factor for thromboembolic events. This study aimed to evaluate homocysteine and its cofators (folic acid and vitamin B12) concentrations and platelet count at diagnosis of BC, 3 and 6 months after the beginning of chemotherapy treatment and to correlate them with clinical data. METHODS: Thirty-five BC patients were included; blood samples were obtained by venipuncture. Plasmatic Hcy and cofactors concentrations were measured by competitive chemiluminescent enzyme immunoassay method. Platelet count was done using an automated analyzer. Statistical analysis was performed using the software SPSS. RESULTS: During chemotherapy, homocysteine (P = 0.032) and vitamin B12 (P < 0.001) concentrations increased, while folate and platelets decreased (P < 0.001). Among the clinical data, the menopausal status showed significant positive correlation (P = 0.022) with homocysteine concentration increase. CONCLUSIONS: Evaluation of homocysteine concentrations during chemotherapy is extremely important because their levels increase during chemotherapy treatment, thus increasing the risk of thromboembolism development.

Endothelial, renal and hepatic variables in Wistar rats treated with Vancomycin.

Vancomycin (VCM) is indicated in combat against Gram-positive infections, but it is not considered a first-choice drug because of its adverse effects. It is believed that oxidative stress is the primary mechanism of endothelial injury and the consequent VCM toxicity, which varies from phlebitis to nephrotoxicity. Moreover, dose recommendations, dilution, rates and types of infusion are still controversial. The aim of this study was to determine the effect of different VCM dilutions in endothelial, liver and kidney injuries by biochemical parameters and histopathological analysis. Wistar rats were randomly divided into six groups and subjected to femoral vein cannulation for drug administration. Control groups received 0.9 ml of saline and the others received VCM (10mg/Kg/day) at dilutions of 5.0 and 10.0 mg/mL for 3 and 7 days. Homocysteine, hs-CRP, AST, ALT, GGT, urea, creatinine, lycopene, alpha-tocopherol, beta-carotene and retinol were analyzed. Kidney, liver and cannulated femoral vein fragments were collected.This study showed alterations in ALT which featured hepatotoxicity. However, drug dilutions were not able to show changes in other biochemical parameters. In contrast, kidney and endothelium pathological changes were observed. More studies are needed to characterize VCM induced kidney and endothelium toxicity and biochemical markers able to show such morphological modifications.

Standardization of a method to study angiogenesis in a mouse model.

In the adult organism, angiogenesis is restricted to a few physiological conditions. On the other hand, uncontrolled angiogenesis have often been associated to angiogenesis-dependent pathologies. A variety of animal models have been described to provide more quantitative analysis of in vivo angiogenesis and to characterize pro- and antiangiogenic molecules. However, it is still necessary to establish a quantitative, reproducible and specific method for studies of angiogenesis factors and inhibitors. This work aimed to standardize a method for the study of angiogenesis and to investigate the effects of thalidomide on angiogenesis. Sponges of 0.5 x 0.5 x 0.5 cm were implanted in the back of mice groups, control and experimental (thalidomide 200 mg/K/day by gavage). After seven days, the sponges were removed. The dosage of hemoglobin in sponge and in circulation was performed and the ratio between the values was tested using nonparametric Mann-Whitney test. Results have shown that sponge-induced angiogenesis quantitated by ratio between hemoglobin content in serum and in sponge is a helpful model for in vivo studies on angiogenesis. Moreover, it was observed that sponge-induced angiogenesis can be suppressed by thalidomide, corroborating to the validity of the standardized method.

Circulating tumor cell detection during chemotherapy in patients with breast cancer is not associated with plasma homocysteine levels.

Breast cancer remains the second most frequent type of cancer in the world and the first among women, and systemic chemotherapy is an adjuvant therapeutic modality that improves survival in a great part of patients. Women with breast cancer, however, frequently show a higher risk of thromboembolism, an event associated to hyperhomocysteinemia and the presence of circulating tumor cells (CTC). Our aim is to correlate the presence of CTCs, detected by the analysis of CK19 and c-erbB2 gene expressions, and the homocysteine plasma levels in the peripheral blood in patients with breast cancer undergoing chemotherapy. Epithelial marker expression (CK19 and c-erbB2) and homocysteine levels were analyzed in a mononuclear fraction of the peripheral blood and plasma, respectively, obtained from 35 patients diagnosed with breast cancer at diagnosis and throughout chemotherapy treatment. No significant relation between the CK19 and c-erbB2 expressions and hyperhomocysteinemia was observed at any moment of the evaluation throughout the chemotherapy treatment (3 and 6 months after the onset). Among clinical data, only menopausal status showed a statistically significant correlation with homocysteine concentration. Although differences in the expressions of the analyzed epithelial markers were detected at 3 and 6 months of chemotherapy treatment, no relation between plasma homocysteine variations and the CK19 and c-erbB2 gene expressions was found in patients under chemotherapy treatment at any moment of the evaluation, suggesting that chemotherapy affects the expressions of the studied genes independently.

Mild systemic oxidative stress in the subclinical stage of Alzheimer's disease.

Alzheimer's disease (AD) is a late-onset, progressive degenerative disorder that affects mainly the judgment, emotional stability, and memory domains. AD is the outcome of a complex interaction among several factors which are not fully understood yet; nevertheless, it is clear that oxidative stress and inflammatory pathways are among these factors. 65 elderly subjects (42 cognitively intact and 23 with probable Alzheimer's disease) were selected for this study. We evaluated erythrocyte activities of superoxide dismutase, catalase, and glutathione peroxidase as well as plasma levels of total glutathione, α-tocopherol, ß-carotene, lycopene, and coenzyme Q10. These antioxidant parameters were confronted with plasmatic levels of protein and lipid oxidation products. Additionally, we measured basal expression of monocyte HLA-DR and CD-11b, as well as monocyte production of cytokines IL1-α, IL-6, and TNF-α. AD patients presented lower plasmatic levels of α-tocopherol when compared to control ones and also higher basal monocyte HLA-DR expression associated with higher IL-1α production when stimulated by LPS. These findings support the inflammatory theory of AD and point out that this disease is associated with a higher basal activation of circulating monocytes that may be a result of α-tocopherol stock depletion.

Effects of ethanol on CYP2E1 levels and related oxidative stress using a standard balanced diet.

Expression of cytochrome P4502E1 (CYP2E1) is very much influenced by nutritional factors, especially carbohydrate consumption, and various results concerning the expression of CYP2E1 were obtained with a low-carbohydrate diet. This study describes the effects of ethanol treatment on CYP2E1 levels and its relationship with oxidative stress using a balanced standard diet to avoid low or high carbohydrate consumption. Rats were fed for 1, 2, 3, or 4 weeks a commercial diet plus an ethanol-sucrose solution. The results have shown that ethanol administration was associated with CYP2E1 induction and stabilization without related oxidative stress. Our findings suggest that experimental models with a low-carbohydrate/high-fat diet produce some undesirable CYP2E1 changes that are not present when a balanced standard diet is given.

Adhesion molecules affected by treatment of lung cancer cells with epidermal growth factor.

Lung cancer is one of the leading causes of death in the world. Some tumor events are attributed to an important group of molecules (cadherins and integrins). We evaluated the interactions of cell adhesion molecules in cell lines from lung cancer. Two lung cancer cell lines were nonmetastatic (H358 and H441) and two were metastatic (H1299 and H292). All cell lines were treated with epidermal growth factor (EGF), and Western blot analysis was performed to assess the interactions between these proteins. The bronchoalveolar cells H358 showed the three analyzed proteins: E-cadherin, ß-catenin, and p120 catenin. The adenocarcinoma cells H441 did not present p120 catenin, and carcinoma cells did not show E-cadherin (H1299) or p120 catenin (H292). FAK (pTyr925) was dephosphorylated in adenocarcinoma cells H441, absent in carcinoma cells H1299, and upregulated in the other carcinoma cells H292. p130Cas showed no difference when the cell lines were treated with EGF for 30 min; it was absent in the metastatic carcinoma cells H1299. Paxillin was dephosphorylated in adenocarcinoma cells H441 and also absent in other metastatic carcinoma cells H292. Vinculin showed the same results, and talin was downregulated in adenocarcinoma cells H441 when the cells were treated with EGF. Rap1 was downregulated and PYK2 was upregulated in the same cell line. Our data help to comprehend the mechanism involved in cell migration to the blood and metastasis generation. In conclusion, the expression patterns of cell-cell adhesion were not affected by EGF treatment but it affected cell-extracellular matrix adhesion.

Insulin resistance and not steatosis is associated with modifications in oxidative stress markers in chronic hepatitis C, non-3 genotype.

BACKGROUND: Modifications of oxidative stress are reported in hepatitis C. The relationship between insulin resistance (IR), steatosis and oxidative stress is not established. MATERIALS AND METHODS: One hundred and eighty-seven HCV-RNA patients were assessed by determination of biochemical, metabolic and viral features, HOMA-IR and morphological alterations. In the 52-non-3 genotypes sub-group and 35 healthy individuals, thiobarbituric acid (TBARS), total glutathione (total-GSH), vitamins C and E, lycopene, beta-carotene, glutathione peroxidase (GPx), catalase and superoxide dismutase were determined. RESULTS: In non-3 genotype patients, steatosis was associated with higher values of BMI, HOMA-IR and triglycerides. In the 52-HCV sub-group, values of TBARS, GPx and total-GSH differ from the control group. Despite these, differences could not be observed according to the presence of steatosis, patients with IR presented significant differences regarding total-GSH (p=0.019), beta-carotene (p=0.006), lycopene (p=0.005) and GPx (p=0.009). CONCLUSION: In non-3 genotype HCV carries, IR, and not steatosis, is associated with modifications in serum levels of oxidative stress.

Aging and oxidative stress.

The scientific establishment has been discussing the relationship between aging and oxidative stress for quite some time now. While we are still far from a general agreement about this subject, there is an impressive amount of data collected that can be used to draw a compelling picture of the events that take place during the human aging process and their correlation with the oxidant status of the organism. In this review, we bring forth the results of some key studies that can help to elucidate the aging-oxidative stress puzzle, as well as to explain which are the fundamental events in this interplay and why their causal relationships remain so elusive. We also put forward here data on the systemic oxidative stress status of a group of 503 healthy human subjects. The data consist of the plasma levels of TBARS and of the nutritional antioxidants, alpha-tocopherol, beta-carotene and ascorbic acid, and of the activity of the antioxidant enzymes, Cu, Zn-superoxide dismutase, catalase and glutathione peroxidase, of red blood cells. The data indicate that a moderate situation of oxidative stress gradually develops during human aging.

Role of beta2-glycoprotein I, LDL-, and antioxidant levels in hypercholesterolemic elderly subjects.

The levels of electronegative low-density lipoprotein (LDL-), LDL cholesterol oxidability, and plasma levels of molecular antioxidants and of beta(2)-glycoprotein I (beta(2) GPI) were studied in a group of 10 hypercholesterolemic (HC) and 10 normocholesterolemic (NC) elderly subjects. HC subjects showed significantly higher levels of cholesterol, LDL cholesterol, LDL-, and beta(2)GPI than NC, whereas high-density lipoprotein cholesterol and alpha-tocopherol levels were lower in HC as compared with NC subjects. Correlations among LDL- levels, LDL oxidation lag time, beta(2)GPI, and antioxidant plasma levels were studied in 100 HC elderly subjects. Lag time for in vitro LDL oxidation positively correlated with ubiquinol-10 levels (p = 0.008), but not with other antioxidants studied or beta(2)GPI. LDL- and alpha-tocopherol levels showed an inverse and significant correlation (p = 0.018). beta(2)GPI and LDL cholesterol levels were correlated (p = 0.001), whereas no significance was found between LDL- and beta(2)GPI levels (p = 0.057). The physiological significance of alpha-tocopherol and ubiquinol-10 levels on LDL- levels, and the presence of high levels of beta(2)-GPI, are discussed in terms of protective mechanisms operating during the overall atherosclerosis process.

Effects of gamma-hexachlorocyclohexane and L-3, 3', 5-triiodothyronine on rat liver cytochrome P4502E1-dependent activity and content in relation to microsomal superoxide radical generation

Liver microsomal cytochrome P4502E1-dependent p-nitrophenol (PNP) hydroxylation and expression of cytochrome P4502E1 were studied in rats subjected to gamma-hexachlorocyclohexane (HCCH) or L-3,3,5-triiodothyronine (T3) administration as a possible mechanism contributing to superoxide radical (O2.-) generation. HCCH treatment (a single dose of 40 mg/kg body wt) produced a 43 per cent increase in the content of total cytochrome P450, whereas T3 (daily doses of 0.1 mg/kg body wt for two consecutive days) led to a 37 per cent decrease. NADPH-dependent O2.- generation was elevated by HCCH and T3, expressed as either per mg of protein or per nmol of cytochrome P450, with a 135 per cent enhancement in the O2.- production/superoxide dismutase (SOD) activity ratios being observed in both conditions. This was partly due to depression of SOD activity. Concomitantly, the molecular activity of NADPH-cytochrome p450 reductase was enhanced by 90 and 69 per cent by HCCH and T3, respectively. In these conditions, microsomal PNP hydroxylation showed increases of 58 and 45 per cent in HCCH- and T3-treated rats over control values, respectively, with a parallel 31 per cent (HCCH) and 41 per cent (T3) enhancement in the content of cytochrome P4502E1 assessed by western immunoblotting. We conclude that HCCH and T3 enhance the expression and activity of cytochrome P4502E1 and that of NADPH-cytochrome P450 reductase in rat liver, regardless of the changes in total cytochrome P450 content, representing major contributory mechanisms to microsomal NADPH-dependent O2.- generation.

Liver necrosis induced by acute intraperitoneal ethanol administration in aged rats.

It is generally agreed that the deleterious pathophysiological effects of ethanol are caused, at least partially by an increase in free radical production. However, little attention has been directed to the effects of ethanol upon elderly organisms. Male Wistar rats at ages 3, 6, 12, 18 and 24 months were treated either with a single i.p. dose of 35% ethanol (v/v) at 3 g ethanol/kg body weight or an isovolumetric amount of 0.9% saline solution. We then assessed the plasma levels of transaminases and hepatic levels of oxidative stress-related parameters, followed by liver histological evaluation. The younger rats (3 months old) were not affected by the treatment with ethanol with respect to any of the studied parameters except for a lowering of total hepatic GSH and an increase in hepatic thiobarbituric acid reactants (TBARS) formation, while animals older than 3 months were increasingly more affected by the treatment. Acute ethanol treatment elicited the similar responses to those in the 3 months-old group, plus a decrease in the hepatic and plasma levels of beta-carotene and the plasma level of alpha-tocopherol, as well as an increase in the activity of plasma transaminases. In the 12,18 and 24 months old groups, there was increasing liver necrosis. These findings suggest that liver damage induced by acute ethanol administration in elderly rats may involve a lack of antioxidants.

Enhancement of lindane-induced liver oxidative stress and hepatotoxicity by thyroid hormone is reduced by gadolinium chloride.

The role of Kupffer cells in the hepatocellular injury and oxidative stress induced by lindane (20 mg/kg; 24h) in hyperthyroid rats (daily doses of 0.1 mg L-3,3',5-triiodothyronine (T3)/kg for three consecutive days) was assessed by the simultaneous administration of gadolinium chloride (GdCl3; 2 doses of 10mg/kg on alternate days). Hyperthyroid animals treated with lindane exhibit enhanced liver microsomal superoxide radical (O2.-) production and NADPH cytochrome c reductase activity, with lower levels of cytochrome P450, superoxide dismutase (SOD) and catalase activity, and glutathione (GSH) content over control values. These changes are paralleled by a substantial increase in the lipid peroxidation potential of the liver and in the O2.- generation/ SOD activity ratio, thus evidencing a higher oxidative stress status that correlates with the development of liver injury characterized by neutrophil infiltration and necrosis. Kupffer cell inactivation by GdCl3 suppresses liver injury in lindane/T3-treated rats with normalization of altered oxidative stress-related parameters, excepting the reduction in the content of GSH and in catalase activity. It is concluded that lindane hepatotoxicity in hyperthyroid state, that comprises an enhancement in the oxidative stress status of the liver, is largely dependent on Kupffer cell function, which may involve generation of mediators leading to pro-oxidant and inflammatory processes.