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Biomedical subjects

H Cramer

Publications and source records attributed to H Cramer.

At least 109 records · Page 6Linked to original sources
PubMed1977

Cyclic AMP in cerebrospinal fluid of manic and depressive patients.

Cyclic 3',5'-adenosine monophosphate (c-AMP) was measured in cerebrospinal fluid (CSF) of manic and depressive patients with and without probenecid administration both before and during treatment with various psychotropic drugs. Oral probenecid (100 mg/kg) produced substantial c-AMP accumulations in CSF suggesting a probenecid-sensitive transport mechanism for c-AMP. Baseline and probenecid-induced accumulations of c-AMP were not significantly different in manic and depressed patients, while baseline levels in depressed patients were higher than those in neurological controls. Imipramine, amitriptyline, lithium, tryptophan, and electroconvulsant therapies did not significantly alter levels or accumulations of c-AMP in CSF of depressed patients.

Administration, Oral↗
PubMed1976

In vitro effects of histamine liberator compound 48/80 on rat superior cervical ganglia with special regard to the small granule-containing cells.

The effect of the histamine liberator compound 48/80 on the rat superior cervical ganglia in vitro has been investigated. After incubation of the ganglia with compound 48/80: (1) ganglionic mast cells degranulate in the same manner as in other tissues; (2) cell bodies of the postganglionic neurons are not affected by compound 48/80; (3) there is evidence that ganglionic interneurons, the monoamine-containing cells are activated. The ultrastructural aspects of this process are characterized by degranulation of perikarya and accumulation of dense core vesicles in cell processes and in terminals adjacent to presynaptic membranes. These vesicles vary in size between 200-800 A in diameter. They may represent storage sites of the neuro-transmitter complexes that have undergone exocytosis. The results are discussed with special reference to models of exocytotic processes involving the adrenergic transmitter. It is concluded that monoamine-containing cells represent interneurons in sympathetic ganglia which inhibit ganglionic transmission and which are stimulated by low concentrations of compound 48/80 in vitro.

Animals↗
PubMed1976

3': 5'-Nucleotide phosphodiesterase in the superior cervical ganglion of the rat. Evidence for multiple forms and influence of the beta-adrenergic receptor system in the electrophoretic pattern of the enzyme.

Two forms of a cAMP phosphodiesterase were found in the superior cervical ganglia of the rat. The influence of various detergents on solubility and activity of the enzyme was studied. Two Km values were determined, one of 0.9mum and the other 270mum cAMP. Separation by polyacrylamide disc electrophoresis revealed four distinct peaks of enzyme activity. One of these activities was increased when ganglia were incubated with adrenaline for at least 4 h. The increase caused by adrenaline was unaffected when ganglia were pre-incubated with cycloheximide, but was blocked in the presence of propranolol, a beta-adrenergic antagonist. Incubation with dibutyryl cAMP for 4 h mimicked the effect of adrenaline. Brief incubation with adrenaline was without effect. Electrophoresis in the presence of 0.1% Lubrol W, a non-ionic detergent, showed that one band of activity disappeared, while the main peak of enzyme activity increased in size. Two-dimensional starch gel electrophoresis confirmed the results of the disc electrophoresis.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1976

[Results of cytologic examinations of the cervix in women under the age of thirty (author's transl)].

154 suspicious and positive findings for carcinoma in women between the ages of 18 and 30 were reported. Included here were 7 cases of invasive carcinoma, 57 cases of epithelial carcinoma, 8 cases of advanced dysplasia and 17 cases of dysplasia in beginning and intermediate stages. The findings from two gynecologic practices in which the physicians annually conducted a cytologic examination of the cervix on every woman, regardless of age, were studied in particular. In both of these practices, 64 of the 89 preliminary stages of carcinoma and carcinoma itself in this age group were discovered in this way. The total material came from 26 contributors. The participation on the part of the young women in both gynecologic practices was unexpectedly high (33% of all those patients receiving preventive examinations). The established practice of conducting cytologic cancer tests on the cervix uteri only after the age of 30 can no longer be justified. One possible causal factor for the increased morbidity and the earlier occurrence of the disease is the coincidence between genital infections and the increased occurrence of neoplasia of the cervix due to earlier onset of sexual activity. It is imperative that women be informed of the increased risks and that they be given the opportunity of a cervical cancer test even before the age of thirty.

Adolescent↗
PubMed1976

[Effects of levodopa and piribedil on cyclic AMP levels in cerebrospinal fluid in rats (author's transl)].

30 min after injection of levodopa (200 mg/kg) into rats the cAMP levels in the cisternal fluid were significantly elevated by 60% over controls. When dopamine-beta-hydroxylase was inhibited by bis-(4-methyl-1-homopiperazinyl-thiocarbonyl)-disulfide (Fla 63) the levodopa induced increase of cAMP levels was less marked, it was suppressed by propranolol (10 mg/kg), a beta-adrenergic blocking agent. Piribedil (10 mg/kg) failed to influence cisternal cAMP concentrations. The findings do not support the concept of a dopamine-sensitive adenylate cyclase in vivo, and suggest a beta-adrenergic stimulation of cerebral adenylate cyclase by metabolites of levodopa.

Animals↗
PubMed1976

Effects of compound 48/80, a histamine-releasing agent, on accumulation and release of cyclic AMP in various regions of rat brain in vitro.

The effect of compound 48/80 in various rat brain regions - by means of incubating brain sclices with compound 48/80 - on cyclic AMP accumulation and release of the nucleotide into the incubation medium was studied. In all regions tested, accumulation of cyclic AMP occurred within at least 10 min. In the cortex, brain stem and cerebellar regions these increases of cyclic AMP could be blocked by propranolol, a beta-adrenergic antagonist. Diphenhydramin, an antihistaminic agent, was without effect in these regions, but could partially block the compound 48/80-induced rise of cyclic AMP in the hypothalamus. Propranolol had in this region only a moderate blocking effect. Release of cyclic AMP, induced by compound 48/80, occurred in all regions tested and could not be effectively blocked by propranolol or diphenhydramin.

Adenylyl Cyclases↗
PubMed1976

[Liberation of growth hormone and melanocyte-stimulating hormone in natural and melatonin-induced human sleep (author's transl)].

As in the early period of night sleep, plasma levels of human growth (HGH) are markedly elevated in afternoon sleep in healthy young males. Melatonin (50 mg i.v.) induces marked secretion of HGH when sleep is prevented. It decreases latencies for sleep onset and deep sleep significantly, and markedly enhances peak secretion of HGH during slow-wave sleep. Plasma melanocyte-stimulating hormone (betal-MSH) levels were influenced neither by melatonin nor by sleep.

Growth Hormone↗
PubMed1975

Cyclic adenosinemonophosphate in cerebrospinal fluid. Effects of theophylline, L-dopa and a dopamine receptor stimulant in rats.

The effects of L-Dopa and the dopamine receptor stimulant ET-495 on cisternal cAMP levels were studied in rats. L-dopa (100-200 mg/kg) increased cisternal cAMP levels by 60 to 80% of controls. When peripheral Dopa-decarboxylase was inhibited, smaller doses of L-Dopa were effective. Fla-63, an inhibitor of dopamine-beta-hydroxylase lowered the increase induced by L-Dopa which was completely suppressed by propranolol, not by phentolamine, suggesting that the cAMP increase is mediated through a central beta-adrenoceptor stimulation. ET-495 failed to influence cAMP levels which argues against a dopamine-sensitive adenylate cyclase involved in the L-Dopa effect. Moreover, large increases of cisternal cAMP were observed after treatment with theophylline , not papaverine which suggests different effects of these "phosphodiesterase inhibitors" on the cyclic AMP systems in the central nervous system or on transport mechanisms.

Animals↗