Exercício contínuo e intermitente: Efeitos do treinamento e do destreinamento sobre a gordura corporal de ratos obesos

Exercise training is often recommended in prevention and treatment of obesity. The present study was designed to compare the effects of intermittent and continuous exercise on weight loss and carcass composition in obese rats. Obese male Wistar rats (monosodium glutamate [MSG] administration, 4 mg/g of body weight every other day from birth to 14 days old) were used. After drug administration, the rats were separated into three groups: MSG-SED (sedentary), MSG-CONT (continuous, swimming, 45 min/day, 5 days/week, with and overload of 5% body weight for 12 weeks) and MSG-INT (intermittent, 15s swimming intermitted by 15s rest, during 45 min, 5 days/week, with and overload of 15% body weight for 12 weeks). Rats of the same age and strain, administered with saline were used as control (SAL), and subdivided into three groups: SAL-SED, SAL-CONT and SAL-INT. The animals were evaluated at the 10 weeks of training and 8 weeks of its interruption. MSG rats showed higher carcass fat as well as weight and cell size in epididymal adipose tissue than SAL rats, indicting the efficacy of the drug in producing obesity. Intermittent training protocol led to a reduction in blood lactate accumulation during acute exercise and both protocols reduced body weight gain during the experiment in MSG rats. After 8 weeks of training interruption no differences were observed among groups in the examined parameters. Only intermittent exercise training improved aerobic fitness but both protocols were similarly efficient in determining weight loss. However, the effects were transitory, since they disappeared after detraining.

Doença arterial coronariana: Um novo paradigma na AIDS

The HIV-infected individuals have been identified as a peculiar group whose propensity to the development of abnormalities in lipids metabolism supports the hypothesis that AIDS itself can be considered as an independent risk factor for the occlusive diseases development. The AIDS progression, as well as the therapy against HIV has been capable to show an array of metabolic disturbances that HIV-infected patients are prone to. These metabolic alterations affect the fate of plasmatic lipids and homocysteine as a result of three factor mainly: (i) the viral infection per se which triggers the development of hypertriglyceridemia and hipocholesterolemia; (ii) multiple vitamins and micronutrients deficiencies, that favors an onset of hyperhomocysteinemia; (iii) the state-of-the-art therapy for HIV infection, which is accompanied to idiosyncratic effects encompassing the lipid metabolism. In this context, a variety of risk factors to atherosclerosis can be identified in the HIV-infected individual. Of note, it must be considered that once life expectancy of these patients has been expanded due to the effective therapy, on the other hand they can accelerate atherosclerotic disease or its pathological appearance in the same extent.

Avaliação da fertilidade e de possíveis defeitos estruturais externos sobre a prole de ratos machos expostos cronicamente ao arsênio

Arsenic is an environmental pollutant that influences the male reproductive function, affecting the spermatogenesis process in the testis and causing alterations in the sperm. The objective of this work was evaluate the reproductive efficiency in adult male rats exposed to arsenic and the possible male-mediated structural malformations. The animal were treated with sodium arsenato (3,6 mg/Kg, i.p.), twice a weak, for 15, 30, 45, 60 or 75 days whereas control received only distilled water. Results have showed a reduced pregnancy rate associated to a decrease in the fertility potencial and to a increase in the preimplantation loss. There was a decrease in the fetal weights, as showed by its average. Malformations rate, postimplantation loss and resorptions were unaffect by treatment. These results suggest that chronic exposure to arsenic provokes reduction on fertility of male rats. Further studies are required to clarify the arsenic effects on male reproductive system and male-mediated effects on progeny.

Diltiazem não induziu crescimento gengival em ratos. Análise clínica, histológica e histométrica

The administration of calcium channel blockers has been associated with gingival overgrowth. However, there are few studies in humans or animals that evaluated the effect of diltiazem on gingival tissues. The present study assessed the influence of diltiazem, at different dosages and treatment duration, on gingival tissues of rats, using clinical, histological and histometric analyses. Eighty young male rats were separated into eight groups according to the dosage and duration of treatment. Rats were treated for 20 or 40 days with a daily subcutaneous injection of 5, 20 or 50 mg/kg of body weight of diltiazem. The results confirmed that diltiazem did not induce gingival overgrowth in rats. For all animals, the evaluation did not show gingival alterations regardless of the dosages and periods of treatment. The histometric analysis showed no significant change in the area of epithelium and connective tissues, although after 40 days of treatment a decrease in the area of connective tissue was observed, without statistically significant difference from control groups. Within the limits of this study, we suggest that diltiazem did not induce gingival overgrowth.

Influence of arginine vasopressin receptor and nitric oxide on the water, sodium intake and arterial blood pressure induce by angiotensin injected into third ventricle of the brain

As several structures of the central nervous system are involved in the control of hydromineral and cardiovascular balance we investigated whether the natriorhexigenic and pressor response induced by the injection of ANG II into the 3rd V could be mediated by vasopressinergic and nitrergic system. Male Holtzman rats weighing 200-250 g with cannulae implanted into the 3rd V were used. The drugs were injected in 0.5 μL over 30-60 sec. Controls were injected with a similar volume of 0.15 M NaCl. ANGII increased the water intake vs control. AVPA injected into 3rd V prior to ANGII decreased the dipsogenic effect of ANGII. L-arginine also decreased the water intake induced by ANGII. AVPA plus L-arginine inhibit the water intake induced by ANGII. 7NIT injected prior to ANGII potentiated the dipsogenic effect of ANGII. Pre-treatment with ANGII increased the sodium ingestion vs control. AVPA decreased the ANGII effect in sodium intake. L-arginine also decreased the natriorhexigenic effect of ANGII. The combination of L-arginine and AVPA inhibit the sodium intake induced by ANGII. 7NIT injected prior to ANGII potentiated the sodium intake induced by ANGII. ANGII induced an increase in Mean Arterial Pressure (MAP) vs control. AVPA and L-arginine induced a decreased in the pressor effect of ANGII. The combination of L-arginine and AVPA inhibit the pressor effect of ANGII. 7NIT injected prior to ANGII into 3rd V potentiated the pressor effect of ANGII. These data suggest that arginine vasopressin V 1 receptors and Nitric Oxide (NO) within the circumventricular structures may be involved in sodium intake and pressor response induced by the activation of ANGII receptors within the circumventricular neurons. These studies revealed the involvement of sodium appetite by utilizing the angiotensinergic, vasopressinergic and nitrergic system in the central regulation of blood pressure. © 2006 Asian Network for Scientific Information.