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Biomedical subjects

E Karasek

Publications and source records attributed to E Karasek.

At least 19 recordsLinked to original sources
PubMed1990

Experiments with volume overload in SHR/Frid and WKY/Frid.

Heart rate, systolic and diastolic blood pressure, and left ventricular pressure were continuously measured in volume overload experiments with SHR and WKY rats. The index for contractility dp/dtmax was determined. The initial data and the changes during overload are tabulated and compared between the strains. Overload led to a marked increase of the end-diastolic left ventricular pressure in WKY rats. The SHR overload model reacts less to the standard drug Dopamine than the normotensive strain. It combines chronic hypertension with acute volume overload and is suitable for circulation basic research and special screening experiments with prospective new cardiovascular drugs. It is bound to a high technical and preparative expenditure.

Animals↗
PubMed1989

Influence of melatonin and N-acetylserotonin on the cyclic AMP concentration in the rat thyroid lobes incubated in vitro.

Effects of melatonin and N-acetylserotonin on the cyclic AMP (cAMP) concentration in the organ-cultured rat thyroid gland were investigated. Exposure of the thyroid explants to melatonin (10(-8) M) resulted in a decrease of cAMP levels. Melatonin at higher concentrations (10(-7) M and/or 10(-6) M) failed to influence the thyroid cAMP level. N-acetylserotonin (10(-6) M), like melatonin in the lowest concentration employed, reduced cAMP concentrations in the thyroid explants when compared with controls. Unexpectedly, melatonin (at a concentration of 10(-7) M) added to the incubation medium with TSH (60 mU/ml), decreased the cAMP concentration in the thyroid compared with the group exposed to melatonin (10(-7) M) alone.

Animals↗
PubMed1985

Colloid droplet accumulation precedes the enhancement of 6-keto-PGF 1 alpha release from the thyrotropin-stimulated thyroid gland.

Influence of thyrotropin (TSH) on colloid droplet formation in thyroid follicular cells and on release of a stable prostacyclin metabolite, 6-keto-prostaglandin 1 alpha (6-keto-PGF 1 alpha) from the thyroid has been studied in rats. Maximal accumulation of colloid droplets preceded the enhancement of the 6-keto-PGF 1 alpha release. Such a time sequence speaks against the possibility of prostacyclin involvement in the thyroid secretory response to TSH.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Prolongation of the survival of skin grafts in mice by PUVA treatment.

The combined application of psoralen and UVA radiation to skin grafts induced a prolongation of the survival time of the grafts in mice. This was observed using the H-Y barrier, an allogeneic barrier without H-2 disparities, and a strong H-2 incompatible barrier. The effect is probably due to a reduction of antigen-presenting cells, or to other, unknown mechanisms.

Animals↗
PubMed1984

Prolongation of skin graft survival in mice by in vitro PUVA treatment and failure of induction of specific immunological memory by PUVA-treated grafts.

Treatment of murine skin grafts in vitro with 8-methoxypsoralen and longwave ultraviolet radiation prolonged their subsequent survival on allogeneic recipients, but not in cases where the recipients had been presensitized by a former skin graft of the same donor strain. In contrast to normal skin, grafts pretreated with 8-methoxypsoralen and longwave ultraviolet radiation were not able to induce an immunological memory as revealed by a second transplantation of normal skin. The results show that primary and secondary skin graft rejection can be affected by the combined action of psoralen and ultraviolet radiation.

Animals↗
PubMed1984

Melatonin inhibits prostaglandin E release from the medial basal hypothalamus of pinealectomized rats.

The effects of pinealectomy and of melatonin administration on prostaglandin E synthesis in the medial basal hypothalamus were studied in male rats. Melatonin treatment significantly decreased prostaglandin E release from the medial basal hypothalamus in pinealectomized rats. The results of the present study suggest that melatonin modulates hypothalamo-hypophyseal function, at least in part, via inhibition of hypothalamic prostaglandin synthesis.

Animals↗
PubMed1981

Effects of dopamine on cyclic AMP concentration in the anterior pituitary gland in vitro.

Effects of different concentrations of dopamine on the cyclic AMP concentration in the anterior pituitary gland were investigated in vitro. Low concentrations of dopamine (10(-9)--10(-8) mol/l) were found to decrease, whereas the high concentration (10(-5) mol/l) increased the cyclic AMP concentration in pituitaries collected from ovariectomized and estradiol-treated females. In contrast, dopamine had no effect on the anterior pituitary cAMP concentration when pituitaries were collected from ovariectomized rats which had not received estrogen replacement. These data show that the action of dopamine on the anterior pituitary cAMP largely depends on the dopamine concentration and the hormonal state of animals.

Animals↗