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Biomedical subjects

J Kaiser

Publications and source records attributed to J Kaiser.

At least 217 records · Page 12Linked to original sources
PubMed1982

Deprivation of paradoxical sleep and intracranial self-stimulation.

Effects of paradoxical sleep deprivation upon intracranial self-stimulation behavior were studied. After stable response rates to electrical brain reward were obtained, rats were assigned to an experimental group in which they were deprived of paradoxical sleep with the pendulum technique for 72 h, to a pendulum control group and to a home-cage control group. In baseline, postdeprivation, and postrecovery sessions, rate-intensity functions for intracranial self-stimulation were determined. Partially in contrast to the literature, no change in the response rate or threshold for brain stimulation was found. The question was raised whether factors accompanying the different paradoxical sleep deprivation techniques rather than paradoxical sleep deprivation itself were responsible for these behavioral differences.

Animals↗
PubMed1981

A community support system's use of state hospitalization: is it still necessary?

The development of the community support system model and other efforts to decentralize psychiatric care for the severely disabled has made the future role of the state psychiatric hospital uncertain. The authors studied patient admissions from a community support program in New York State to a state psychiatric hospital over a period of 18 months. They found that the program made very little use of the state hospital, accounting for only ten of the county's 33 admissions. The findings also suggest that refractory patients, staff fatigue, and restrictive utilization review criteria applied to the local general hospital were the primary reasons for continued use of the state hospital. The authors conclude that while the state hospital's front-line treatment role may no longer be necessary, the institution may be needed to care for those few patients whose illnesses do not respond well to current treatment alternatives.

Community Mental Health Services↗
PubMed1980

[The specificity of action of penbutolol and propranolol and their optical isomers].

Several specific and unspecific effects of penbutolol and propranolol and their optical isomers were tested in the following test models: -- The beta-sympatholytic activity in the heart of the anaesthetized dog (measurement of the contractility), -- the sympathomimetic intrinsic activity in the reserpinized rat, -- the antiarrhythmic activity in the digoxin poisoned guinea pig, the digitoxin/aconitine poisoned isolated guinea pig heart, and the cooled cat, -- the beta-sympatholytic activity together with electrophysiological effects in the isolated guinea pig papillary muscle. The antiarrhythmic effects of l-penbutolol are mainly due to its beta-sympatholytic activity. d-Penbutolol reveals only a local anaesthetic action and is otherwise nearly without pharmacological effects. In beta-sympatholysis it is 50 times less active than l-penbutolol. It has no intrinsic sympathomimetic activity. It does not prolong the refractory period in the heart muscle. For this reason only l-penbutolol is proposed to be used as a beta-sympatholytic drug.

Action Potentials↗
PubMed1980

[On the pharmacology of the beta-receptor blocker penbutolol (author's transl)].

1-tert.-Butylamino-3-(2-cyclopentylphenoxy)-propan-2-ol (penbutolol, Hoe 893d) is a beta-adrenergic blocking agent about 4 times more active than propranolol in vivo and in vitro. In comparison to propranolol it is characterized by a longer lasting activity. The antihypertensive effect of penbutolol in spontaneously hypertonic rats is more than 5 times stronger than that of propranolol. Penbutolol reduces basal plasma renin activity in the same dose range as does propranolol but is about 3 times stronger with respect to isoproterenol-induced increase of PRA. Penbutolol is 5 times more potent than propranolol inhibiting isoproterenol-stimulated phosphorylase activity in the isolated heart. In reserpine pretreated rats, penbutolol has a moderate intrinsic sympathomimetic activity (ISA). Penbutolol shows less unspecific actions -- such as negative inotropy or calcium antagonism -- than propranolol. Characteristic parameters of lung function (compliance and resistance) are less affected by penbutolol than propranolol in spite of the fact that penbutolol has a stronger beta-adrenergic blocking effect.

Animals↗
PubMed1976

Cell mediated immunity to herpes simplex in man. IV. A correlation of lymphocyte stimulation and inhibition of leukocyte migration.

The cell mediated immune response to herpes simplex virus was assessed by a modification of the leukocyte migration inhibition test, developed to increase its sensitivity and correlated with the in vitro stimulation of lymphocytes. The introduction of a preincubation step allowed us to demonstrate significant inhibition of leukocyte migration in 15 out of 24 subjects susceptible to recurrent herpes labialis. This was not present in any of the 10 subjects without such infections. However lymphocytes from all 24 subjects demonstrated stimulation in response to herpes virus antigen. The degrees of lymphocyte stimulation and migration inhibition in the susceptible subjects were well correlated and do not support the suggestion that there is a focal defect in this aspect of the cell mediated immune response to herpes simplex virus in those patients.

Antigens, Viral↗
PubMed1976

Hypotensive and antiarrhythmic effects of a new alkaloid, the 13-hydroxylupanine-2-pyrrolcarbonic acid ester, from the Madagascan plant Cadia ellisiana.

The alkaloid 13-hydroxylupanine-2-pyrrolcarbonic acid ester (Hoe 933) from the Madagascan plant Cadia ellisiana has an hypotensive and antiarrhythmic effect. The hypotensive effect in dogs, monkeys, and rats anaesthetized with barbiturates reaches its maximum with 0.2 mg/kg i.v. However, the hypotensive effect is much weaker in conscious animals. The enteral absorption in the dog is good; an intraduodenal dose of only 0.5 mg/kg lowered the blood pressure. In the isolated rabbit heart whose accelerator nerves were intact, the perfusion with concentrations of 0.6 mug/min Hoe 933 (total dose 6 mug) decreased the release of norepinephrine from the nerve endings, reduced the positive inotropic effect, and diminished the increase in heart rate produced by electrical stimulation of the accelerator nerve. The effect of the stimulation of the accelerator nerve on dp/dt in dogs in situ was considerably diminished by such low doses as 10 and 25 mug/kg i.v. Consequently, the alkaloid inhibits sympathetic impulse transmission. Sympathetic circulatory reflexes are weakened by the compound. The alkaloid has also a ganglionic blocking effect, which is demonstrated on the upper cervical ganglion of the cat. The effect of preganglionic stimulation of the nictitating membrane was reduced with 200 mug Hoe 933/kg i.v. In the isolated guinea pig heart the effect of nicotine on heart rate and contraction was diminished. In this respect the ganglion blocker pentolinium is 8 times more active. The antifibrillatory effect of Hoe 933 was demonstrated with 0.3 mg/kg i.v. in supercooled cats, the antiarrhythmic activity was evident with 0.5 mg/kg i.v. in dogs intoxicated with K-strophanthin. In isolated hearts of guinea pigs, a dose of only 6 mug/heart inhibited ventricular fibrillation induced by aconitine and digitoxin. Even the toxicity of digoxin was diminished by previous administration of 300 mug/kg i.v. The relative refractory period and the duration of the action potential were prolonged in the isolated papillary muscle of the guinea pig heart.

Alkaloids↗
PubMed1975

Pathogenesis of fungal infection on heart valve prosthesis.

Four patients with heart valve prostheses developed Candidate endocarditis. At autopsy the foci of infection were confined to patches of neoendocardium that appeared to have developed as ingrowths of host endocardium onto the sewing cloth of the artificial valve. This suggested that one mechanism of fungal infection is related to the presence of the neoendocardium rather than to the cloth or metallic substances of the valve itself. Future studies might be directed toward inhibiting the development of the neoendocardium or to agents preventing its susceptibility to infection.

Adult↗