Effect of acute hypoxia on blood catecholamine and whole blood platelet aggregation

Experiments were performed on 250-300 g male Sprague-Dawley rats under urethane (700 mg/kg) and alpha-chloralose (35 mg/kg) anesthesia. Plasma catecholamine concentration and the whole blood platelet aggregation were measured during normoxia, acute hypoxia, reoxygenation, acute hypoxia immediately after bilateral adrenalectomy and acute hypoxia at the end of 15 and 30 min after bilateral adrenalectomy. The plasma adrenaline concentration and the whole blood platelet aggregation increased markedly (P < 0.01), while the plasma noradrenaline concentration tended to increase (P > 0.05) during acute hypoxia. The plasma adrenaline concentration and the whole blood platelet aggregation are capable of restoring to the normal level during reoxygenation. The plasma noradrenaline concentration did not change, while the plasma adrenaline concentration and the whole blood platelet aggregation decreased significantly (P < 0.001 or 0.05) during acute hypoxia for 15 min immediately after bilateral adrenalectomy. On the other hand, plasma adrenaline and noradrenaline were not detectable during acute hypoxia 30 min after bilateral adrenalectomy while the whole blood platelet aggregation deceased markedly (P < 0.01). When adrenaline (1 ng/ml) was added to the blood (in vitro), the whole blood platelet aggregation increased significantly (P < 0.01). All the above results indicate that acute hypoxia leads to increament of whole blood platelet aggregation and plasma adrenaline concentration due to release from the adrenal gland and the increament of the whole blood platelet aggregation may be partly mediated by increased plasma adrenaline.     

Effect of electrical stimulation of the hypothalamus on the process of blood platelet aggregation

Stimulation of hypothalamic ventromedial and posterior nuclei via implanted electrodes was followed by phasic changes of the blood coagulation processes and thrombocytes dynamic functions. Within the first minutes after stimulation, an increase of the blood coagulation potential, of aggregation and adhesive features of thrombocytes was observed, replaced later by reduction of thrombocytes dynamic features and by decreasing blood coagulation potential. The above changes are associated with alteration of the blood content of aggregating agents, inhibitors of aggregation, and blood coagulating factors. The hypothalamic structures are suggested to exert control over thrombocytes hemostatic functions via a humoral link.     

Effect of desympathization on thrombocyte aggregation capacity and the blood clotting potential of rats

It was shown that platelet aggregation in partially (with stellate ganglia containing 25% neurons of normal amount) and completely (0,5% neurons) sympathectomized rats was significantly lower than in intact animals. Concurrently the blood coagulation system of sympathectomized rats was hyperactive. The reasons for sympathectomy-induced changes seems likely to be elevated adrenalin blood concentration in such rats.     

Daily variations of platelet aggregation in relation to blood and plasma serotonin in diabetes

INTRODUCTION: An increase in digitalis-like substances has been reported in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. We hypothesized that the role of saline and unilateral nephrectomy in DOCA hypertension may be due to stimulation of endogenous digitalis-like substances. METHODS: We investigated the effects of digoxin and DOCA alone and in combination in intact rats drinking water. Forty male Sprague-Dawley rats were used (body weight 223-298 g). RESULTS: Neither digoxin (40 micrograms/kg per day, by gavage, for 35 days, n = 10) nor DOCA (30 mg/kg twice a week, subcutaneously, for 5 weeks, n = 10) caused a consistent increase in blood pressure in intact rats drinking water. In contrast, combined digoxin and DOCA administration (n = 10) increased systolic blood pressure from day 18 of treatment onwards, to a maximum at day 34 compared with sham-treated rats (n = 10). There were no consistent changes in water intake, urine volume, urinary sodium or potassium excretion, or plasma sodium or potassium concentration with digoxin treatment. DOCA increased water intake and urine volume, and caused an initial decrease in urinary sodium excretion, but no change in urinary potassium excretion or plasma sodium concentration. Plasma potassium excretion was lower in DOCA- than sham-treated rats. CONCLUSION: Combined digoxin and DOCA administration in intact rats drinking water increased blood pressure significantly compared with either drug alone, raising the possibility that the mechanism by which nephrectomy and salt loading contribute to DOCA hypertension in the rat might be through stimulation of endogenous digitalis-like substances.     

Effect of chlorpromazine on blood glucose and plasma insulin in man

In three groups of normal subjects and in one group of patients with latent diabetes mellitus a study has been made of the effects of chlorpromazine (CPZ) on blood glucose and plasma insulin. CPZ 75 mg/day for 7 days did not alter the plasma insulin response after oral glucose; nor did CPZ 50 mg/day for 7 days affect the glucose assimilation rate or insulin response to glucose injection. Infusion of CPZ 50 mg in 60 min slightly increased the basal blood glucose level but had no significant effect on basal plasma insulin. The insulin/glucose ratio after the end of the infusion was significantly higher than during the period of infusion of the drug. In latent diabetic patients CPZ infusion significantly diminished the insulin/glucose ratio during an intravenous glucose tolerance test. These results suggest that, whereas prolonged treatment with low doses of CPZ did not modify glucose tolerance and glucose-stimulated pancreatic response, higher acute doses of the drug may induce hyperglycaemia and can inhibit insulin secretion both in normal man and in patients with latent diabetes mellitus.     

Effect of nonselective beta-adrenergic blockade on blood plasma levels of glucagon in plasma during insulin-induced hypoglycemia

An effect of nonselective beta-adrenergic blockade with propranolol on the blood plasma level of glucagon during insulin-induced hypoglycemia was studies in 20 control dogs and 20 alloxan diabetic dogs. Increased sensitivity to exogenous insulin and prolonged hypoglycemia were noted during nonselective beta-adrenergic blockade. However, glucagon response to insulin-induced hypoglycemia following propranolol administration was increased.     

High levels of factor VIII--related antigen in cadaveric blood

The effect of chronic consumption of alcohol on the circadian variations of the plasma corticosterone investigated in DBA/2J male mice. After 15 weeks of alcohol consumption (3.8%w/v for the first week and 7.5% for subsequent weeks) the alcohol groups exhibited a flattened circadian corticosterone curve, the level being intermediate between the peak and trough values of the water control groups. The diurnal patterns of food and liquid consumption were still present at the 10th week of alcohol treatment in the alcohol groups, although the absolute amount of food and liquid consumed at each of the 6-h intervals was somewhat different between the alcohol and water groups. The blood alcohol showed a peak at early morning with the mean of 100 mg/100 ml, but the levels of alcohol during the remaining periods were remarkably stable, the means ranging from 30 to 46 mg/100 ml. Chronic consumption of alcohol, even relatively low concentrations, appears to affect the neural sites in the CNS controlling the circadian rhythm of ACTH release.     

Effect of xanthinol nicotinate treatment on platelet aggregation

Treatment of 24 male patients with 3 g/day of xanthinol nicotinate did not change the in vitro measurements of ADP-induced platelet aggregation but produced a marked inhibition of collagen-induced platelet aggregation. This effect may be connected with the drug-induced depression of the ATP level in platelet-rich plasma. Changes in the platelets in the patients' blood or in the lipid composition and the concentration of uric acid in their serum were ruled out as reasons for the decrease of the collagen-induced aggregation. The activity of the three serum enzymes y-GT, GOT, and GPT and the concentration of the blood sugar did not change.     

In vitro radioautographic studies of the biodistribution of radiopharmaceuticals on blood elements

Alpha-tocopherol and bilirubin antioxidant properties were evaluated in sickle cell disease. The total peroxyl radical trapping antioxidant activity of plasma (TRAP) was measured with a polarographic method using hemin as oxidative stress initiator. The TRAP was not correlated with plasma alpha-tocopherol concentration. The TRAP was correlated with plasma total bilirubin concentration [TRAP = 8.1 (total bilirubin) +363.7 (r = 0.67)] and the correlation was even better with the sum (alpha-tocopherol + total bilirubin) plasma concentration [TRAP = 9.1(alpha-tocopherol + total bilirubin)+ 170.5(r = 0.77)]. The alpha-tocopherol contribution in the antioxidant capacity of plasma was significant but bilirubin level acted as the limiting factor of plasma antioxidant capacity in sickle cell anemia. This result can be explained by the antioxidant property of bilirubin but also by coantioxidant activity towards oxidized alpha-tocopherol.     

Effect of whole blood storage on factor VIII recovery in fresh frozen plasma and cryoprecipitate

BACKGROUND: Evaluate two recent tests for HIV infection diagnosis using the Enzyme-Linked Fluorescent Assay (ELFA) technique for rapid diagnosis in microbiology or virology laboratories. METHODS: A panel of 429 sera with different Ab prevalencies and different sources was prepared: 50 blood bank samples from habitual donors; 8 with positive results from other blood banks; 50 from individuals infected with HIV at various stages; 164 from subjects having practices of risk, with a prevalence of 24.4%; and 157 hospital samples selected at random, with a prevalence of 12.2%. All the samples were analyzed using IMX HIV-1/HIV-2 (ELFA A) and VIDAS HIV-1+2 (ELFA B) tests. Samples yielding positive results from either of the two tests were confirmed by WB. In the cases of indeterminate WB, p24 antigenemia was detected, the positive cases being confirmed by neutralization. RESULTS: From the panel of sera studied, 112 samples were reactive by ELFA A and 109 by ELFA B. The concordance between both assays was 97.3% for reactive samples and 99.1% for non-reactive. WB confirmation showed a global sensitivity of 100% in both tests, with a specificity of 98.4% for ELFA A and 99.3% for ELFA B. Three samples positive for both tests but indeterminate for WB corresponded to sera in the seroconversion window period, one with positive p24 antigenemia. CONCLUSIONS: The new ELFA technology is shown to be an adequate rapid, automatized diagnosis method which decreases risks from laboratory manipulation, with good sensitivity and specificity characteristics for the diagnosis of Ab HIV in health care settings.     

Effect of emotional stress on platelet aggregation in humans

Atypical fibroxanthoma of the skin has been recognized recently as a pseudo-malignant tumor, probably reactive in nature. By all the classic morphological criteria, the lesion appears to be malignant--but in behavior it is benign. In older patients the head and neck are primarily involved, while in younger patients these tumors appear on the covered areas of the trunk and limbs. Complete local excision is considered to be adequate treatment.