Effect of ICV infusion of CRF on blood pressure and adrenal steroids in rabbits

The effect of prolonged, 22 h long, intracerebroventricular (i.c.v.) infusion of corticotropin-releasing hormone (CRF) on plasma cortisol, corticosterone and electrolyte concentrations, mean arterial blood pressure (MAP) and heart rate (HR) were investigated in conscious rabbits. During i.c.v. infusion of CRF, 1 and 3 μ/h, at a rate of 17 μl/h, plasma cortisol and corticosterone concentrations rose to the level noted after ACTH stimulation in rabbits. Plasma [Na] did not change, but plasma [K] was reduced and plasma osmolality increased during the infusion of CRF, 3 μ/h. MAP and HR, recorded continuously during i.c.v. infusion of CRF, changed only with the higher dose of CRF: MAP was elevated during the first 5 h of infusion, and then returned to the control level. HR was lower than control at the end of the first hour of infusion and again between 9 and 15 h of infusion. The prolonged rise of CRF concentration in the brain induced a sustained rise in circulating adrenal steroid hormones. MAP did not increase to the level noted after bolus i.c.v. injection of CRF and the rise in MAP was not sustained.     

Relations between basal ganglia and hippocampus: action of substantia nigra and pallidum

Several interrelationships exist between basal ganglia and hippocampus. The ventral striatum appears to be involved in the control of the dopaminergic nigro-striatal pathway. The caudate, in turn, seems to influence the hippocampal theta rhythm and to inhibit hippocampal spikes. In the present work the role played by globus pallidus pars interna and substantia nigra pars compacta on hippocampal bioelectrical activity is studied. Injection of sodium penicillin i.v. produces steady interictal spikes in the hippocampus. Substantia nigra stimulation induces regular theta rhythm and inhibits the spikes. Pallidal stimulation, on the contrary, appears to strongly enhance epileptiform activity, proceeding to generalised seizure activity. The results are discussed in the light of a putative feedback loop from basal ganglia to hippocampus, probably underlying co-participation of the two subcortical structures in the control of motor behaviour.     

Food intake measured by an automated food-selection system: relationship to energy expenditure.

Measuring food intake in a laboratory usually involves limited food choices. An automated food-selection system with two vending machines containing a large variety of foods was used to measure food intake in 10 male volunteers (31 +/- 6 y, 69.2 +/- 7.1 kg, 18 +/- 7% fat, mean +/- SD) on a metabolic ward. The effect of carbohydrate, fat, and protein intakes on 24-h energy expenditure (24EE) and substrate oxidations was measured in a respiratory chamber during day 4 of weight maintenance and day 7 of ad libitum intake. Ad libitum intake resulted in a 7-d overfeeding of 6468 +/- 3824 kJ/d above weight-maintenance requirements, leading to a 2.3 +/- 1.2-kg gain. The 10,975 +/- 3774 kJ excess energy intake on day 7 of ad libitum intake caused a 1205 +/- 920 kJ/d increase in 24EE (delta 24EE = 0.17 x delta intake - 695; r = 0.71, P less than 0.02). Of the excess carbohydrate intake, 74% was oxidized (r = 0.86, P less than 0.001), whereas excess fat intake was not. Carbohydrate and protein stores are regulated whereas excess fat intake is channeled to fat stores.     

Evaluation of single-dose ciprofloxacin in the eradication of Neisseria meningitidis from nasopharyngeal carriers.

The ability of a single oral 750-mg dose of ciprofloxacin to eradicate Neisseria meningitidis from persistent nasopharyngeal carriers was prospectively evaluated in a placebo-controlled, randomized, double-blinded study. Cultures of specimens taken from all 23 ciprofloxacin-dosed subjects 1 day postdose were negative; cultures from 96% of these subjects were negative at 7 and 21 days postdose, including a specimen from a subject colonized with a minocycline-resistant strain. Of 22 placebo recipients, 20 (91%) remained culture positive. Single-dose ciprofloxacin appears efficacious for meningococcal prophylaxis.