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Biomedical subjects

A Geisler

Publications and source records attributed to A Geisler.

At least 73 records · Page 4Linked to original sources
PubMed1977

A simple and inexpensive protein binding assay for cyclic AMP in biological materials.

We have developed a simple and inexpensive method for largecapacity cAMP determination in biological materials. The assay is based on competitive binding of 3H-cAMP to proteins isolated from rabbit skeletal muscle. Bovine serum albumin is added to the incubate to reduce non-specific interference. Separation of free and bound radioactivity is performed by (NH4)2SO4 precipitation allowing determination of either free or bound fraction. In the latter case, all procedures are performed in the same tube, to which is finally added 1.2 ml of scintillation fluid for counting. By this only one fourth. The method has been applied to rat tissue extracts and urine with satisfactory sensitivity, precision and accuracy.

Ammonium Sulfate↗
PubMed1977

Antidiuretic and urinary cyclic AMP response of vasopressin in normal rats and in rats with lithium-polyuria.

The antidiuretic and urinary cyclic AMP response to supramaximal vasopressin infusion was studied in normal rats and in rats with lithium-polyuria. The animals were anaesthetized and then infused with a solution designed to produce excessive water diuresis and to lower basal cyclic AMP excretion. In 6 control animals not infused with vasopressin (1) urinary cyclic AMP excretion decreased during the infusion period. Vasopressin infusion (300 muU/min.) consistantly induced antidiuresis in all of 13 control rats (II); but the urinary cyclic AMP response varied individually from a significant increase in 6 animals to either no change or to a decrease in the remaining animals. The antidiuretic response to vasopressin was inhibited by 85% in 10 animals with marked polyuria induced by lithium administration (III). None of the animals in this group showed a significant increase of cyclic AMP excretion in response to vasopressin. The average rate of cyclic AMP excretion, which was equal in the two groups before vasopressin, was signifimantly lower in group III than in group II during vasopressin infusion. It is suggested that the increase in cyclic AMP excretion during vasopressin antidiuresis, although not consistant, most likely reflects hormone-induced changes of intracellular cyclic AMP levels in the renal medulla. Thus, the data suggest that the nephrogenic diabetes insipidus syndrome produced by lithium is associated with a defect in the renal formation of cyclic AMP in response to vasopressin.

Animals↗
PubMed1976

Cyclic AMP levels in cerebrospinal fluid in manic-melancholic patients.

The concentrations of adenosine 3'5'-cyclic monophosphate (cyclic AMP) in cerebrospinal fluid (CSF) in manic-melancholic patients were studied. As control groups served patients suffering from other psychiatric disorders as well as neruological and orthopedic patients. The results showed no difference between the various diagnostic groups, including melancholic versus manic patients, unipolar versus bipolar types. The severity of the affective states measured by rating scales showed no correlation to cyclic AMP levels in CSF. The cyclic AMP levels were apparently not influenced by electroconvulsive therapy or treatment with lithium, neuroleptica, or tricyclic antidepressants.

Adolescent↗