Pyruvate dehydrogenase activity in several tissues of genetically obese hyperglycemic mice

The active form (PDHa) and total activity of pyruvate dehydrogenase (PDH) were measured in homogenates from heart muscle, epididymal fat pads and liver of genetically obese hyperglycemic mice and compared with similar data derived from lean controls or Swiss albino mice. Both PDHa and total PDH activities were similar in heart muscle from all mice with a precipitous decrease in the PDHa upon fasting. Adipose tissue and liver of obese mice had a PDHa level that was almost two-fold higher than either lean control or Swiss albino mice. Fasting for 24 hours decreased the elevated activity of PDHa in adipose tissue and liver in obese mice to a value that was comparable to lean control or Swiss albino mice, fasted similarly. The elevation in both the active form and total activity of pyruvate dehydrogenase in livers from obese mice could explain the increased provision of acetyl-CoA units necessary for the accelerated hepatic lipogenesis observed with this mouse, a model for human obesity and insulin resistance.     

Effect of avitaminosis B6 in mice on the function of the T-lymphocytes in vitro]

The influence of different degrees of avitaminosis B6 in mice on the cytolytic activity of T-lymphocytes measured by the amount of Na2Cr51O4 released from the lysed target cells was studied on a model of primary immune response in a mixed lymphocyte culture in vitro. Keeping of the animals for 3 weeks on pyridoxine-free diet failed to influence the capacity of lymphocytes to proliferate in vitro and their cytolytic activity. In animals on pyridoxine-free diet for 45 days the amount of pyridoxal 5(1)-phosphate in the spleen decreased by 55% in comparison with control. Lymphocytes obtained from these animals and cultivated in vitro had a markedly decreased capacity to 3H-thymidine incorporation into DNA in response to alloantigen. The cytolytic activity of these lymphocytes also diminished. The capacity of various pyridoxine forms to restore T-lymphocyte functions disturbed by avitaminosis B6 was studied.     

Study of the restoration and balance of thiamine in the tissues of albino mice in alcoholic intoxication

Acute inhalative alcoholic intoxication has been studied for its effect on the influx and level of free and bound thiamine in tissues of white mice. It is established that acute inhalative ethanol intoxication increases 35S-thiamine incorporation in tissues and decreases the level of endogenic free and bound thiamine. The results obtained permit a conclusion on intensification of the thiamine renewal in tissues with its sufficient influx from outside as affected by the ethanol narcosis.     

Effects of hydralazine on the blood flow in RIF-1 tumors and normal tissues of mice

Hydralazine is a peripheral vasodilator used as an antihypertensive agent. Hydralazine has been reported to potentiate tumor damage by hyperthermia as well as by hypoxic-cell-specific drugs through the reduction of tumor blood flow and pO2. In the present study, we investigated the changes in blood perfusion caused by hydralazine in S.C. RIF-1 tumors and normal tissues in C3H mice using the 86Rb uptake technique and laser Doppler flowmetry. The tumor blood flow was decreased significantly by an intravenous administration of 0.5-10.0 mg/kg hydralazine, as determined by both uptake of 86Rb and laser Doppler flowmetry. The tumor pO2 was also decreased significantly by the injection of hydralazine. On the other hand, the uptake of 86Rb was increased significantly in the skin and muscle by hydralazine. The changes seen in the skin and muscle after injection of hydralazine as assessed by laser Doppler flowmetry were similar to those assessed by uptake of 86Rb, indicating a significant increase in blood circulation in these tissues. Uptake of 86Rb remained unchanged in the kidney and decreased in the liver and spleen in the presence of hydralazine in a dose-dependent manner at 0.5-10.0 mg/kg. The decline in uptake of 86Rb in normal tissues strongly suggests that hydralazine decreases the blood flow in these normal tissues. Thus the recent proposal to use hydralazine to increase the antitumor activity of heat or certain drugs needs to be reexamined.     

Prolonged viral RNA detection in blood and lymphoid tissues from coxsackievirus B4 E2 orally-inoculated Swiss mice

The spreading of viral RNA within Swiss Albino mice orally inoculated with coxsackievirus B4 E2 strain (CVB4 E2) was studied by using RT-PCR and semi-nested-RT-PCR methods. Viral RNA was detected in various organs: pancreas, heart, small intestine, spleen, thymus, and blood at various postinfectious (p.i.) times ranging from 8 hr to 150 days. Our results show that (i) outbred mice can be infected with CVB4 E2 following an oral inoculation, which results in systemic spreading of viral RNA, (ii) CVB4 E2 infection can be associated with a prolonged detection of viral RNA in spleen, thymus and blood, up to 70 days p.i. and further in other organ tissues.