OBJECTIVE: To assess the effect of endogenous estrogens on the bioavailability of nitric oxide (·NO) and in the formation of lipid peroxidation products in pre- and postmenopausal women. METHODS: NOx and S-nitrosothiols were determined by gaseous phase chemiluminescence, nitrotyrosine was determined by ELISA, COx (cholesterol oxides) by gas chromatography, and cholesteryl linoleate hydroperoxides (CE18:2-OOH), trilinolein (TG18:2-OOH), and phospholipids (PC-OOH) by HPLC in samples of plasma. RESULTS: The concentrations of NOx, nitrotyrosine, COx, CE18:2-OOH, and PC-OOH were higher in the postmenopausal period (33.8±22.3 mM; 230±130 nM; 55±19 ng/mL; 17±8.7 nM; 2775±460 nM, respectively) as compared with those in the premenopausal period (21.1±7.3 mM; 114±41 nM; 31±13 ng/mL; 6±1.4 nM; 1635±373 nM). In contrast, the concentration of S-nitrosothiols was lower in the postmenopausal period (91±55 nM) as compared with that in the premenopausal p in the premenopausal period (237±197 nM). CONCLUSION: In the postmenopausal period, an increase in nitrotyrosine and a reduction of S-nitrosothiol formation, as well as an increase of COx, CE18:2-OOH and PC-OOH formation occurs. Therefore, •NO inactivation and the increase in lipid peroxidation may contribute to endothelial dysfunction and to the greater risk for atherosclerosis in postmenopausal women.

Com atividade antioxidante e estrogênica, isoflavonas de soja têm sido associadas à diminuição do risco de câncer e doenças cardiovasculares. Assim, buscou-se nesse trabalho a padronização de um método de extração de isoflavonas a partir do melaço de soja e avaliar a respectiva concentração plasmática e urinária após o consumo deste extrato, em coelhos. As isoflavonas foram extraídas em etanol 90% e purificadas em uma coluna de extração em fase sólida C18, obtendo-se rendimento de 81%. O extrato purificado foi adicionado à dieta dos animais (5 mg de isoflavonas/kg de peso corporal/dia), que foram observados por período experimental de 6 meses. A concentração das isoflavonas (genisteína e daidzeína) dos extratos, da ração, do plasma e da urina foi determinada por CLAE. A concentração média de isoflavonas no plasma foi de 4 mM e a excreção urinária foi de 22 mmoles/24 horas. A purificação das isoflavonas a partir do melaço de soja resultou em preparação adequada para estudos experimentais.

Soy isoflavones show antioxidant and estrogenic effects and have been related to decreased risk of cancer and cardiovascular diseases. The goal of the present study was to standardize the extraction of isoflavones from soy molasses and to evaluate the plasmatic and urinary concentrations of isoflavones in rabbits after consumption of extracted isoflavones. Isoflavones were extracted with 90% ethanol and purified with a C18 column. The extraction yield was 81%. The purified isoflavone extract was added to the chow (5 mg isoflavone/ kg body weight/ day) used for feeding rabbits during 6 months. The concentration of isoflavones (genistein and daidzein) in the extracts, chow, blood plasma and urine was determined by high performance liquid chromotagraphy. The mean concentration of isoflavones in blood plasma was 4 mM and the urinary excretion was 22 µmol/24 h. The extraction of isoflavones from soy molasses resulted in a suitable preparation for experimental studies.

Lipid and acute-phase protein alterations have been described in various infection diseases, and they have been recorded during the early stages of HIV infection. Lipid and acute-phase protein profiles also have been correlated with cellular immunological abnormalities. To document these correlations during HIV infection, we studied 75 HIV-infected patients and 26 HIV-negative controls. Patients were classified according to the criteria proposed by the Walter Reed Army Institute: as WR-1 (CD4 lymphocytes, 1154 ± 268/mm³), WR-2 (CD4, 793 ± 348/mm³) and WR3/4 (CD4, 287±75 mm³). Triglycerides, total cholesterol and HDL-cholesterol concentrations were measured by enzymatic methods. Immunoglobulins (IgA and IgG) and acute-phase proteins (haptoglobin, a1-acid glycoprotein, C-reactive protein and transferrin) were determined by immunonephelometry. Haptoglobin levels were significantly increased in HIV-positive patients and correlated with the progression of HIV-infection (control<WR1<WR2<WR3/4). WR-2 and WR-3/4 patients had lower total cholesterol, HDL-cholesterol, and albumin concentrations, however, a1-acid glycoprotein and IgA levels were higher, when compared to HIV-negative controls. Elevated triglyceride levels (1.51±0.75 mmol/L) were found only in WR3/4 patients, when compared to the control individuals (1.05±0.04 mmol/L). No differences were found in transferrin and C-reactive protein concentrations among the studied groups. CD4+ lymphocyte counts were inversely correlated with triglycerides, IgA, a1-acid glycoprotein and haptoglobin, and they were positively correlated with albumin, total cholesterol and HDL-cholesterol. Multiple linear regression analysis showed that increased haptoglobin and IgA levels were the best predictive variables of a decreasing CD4+ lymphocyte count. In conclusion, our data showed that: 1) a decrease in total cholesterol, HDL-cholesterol and albumin levels occurred earlier than hypertriglyceridemia in the course of HIV infection; 2) increased levels of haptoglobin occurred earlier than that of a1-acid glycoprotein and IgA; 3) haptoglobin and IgA were the best predictive variables of a decreasing CD4+ lymphocyte count. Decreases in HDL-cholesterol and albumin levels with increases in haptoglobin, a1-acid glycoprotein, IgA, and triglycerides levels are indications of disease progression in HIV-infected patients.