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Biomedical subjects

R Ziegler

Publications and source records attributed to R Ziegler.

At least 541 records · Page 30Linked to original sources
PubMed1976

Hypoglycemia in diabetics.

Hypoglycemia in diabetes can be divided into 1) spontaneous hypoglycemic reactions due to absolute or relative overproduction of endogenous insulin or some other blood glucose-lowering substance, as in islet cell adenoma or carcinoma, latent or protodiabetic conditions, (extrapancreatic) tumors and pituitary and/or adrenal disorders; and 2) hypoglycemia caused by exogenous, i.e. therapeutic, measures. The problem of hypoglycemia in insulin-treated diabetics is far from being solved. As revealed by continuous blood glucose monitoring, nocturnal hypoglycemic attacks frequently escape attention especially in juvenile diabetics. Circadian variations in peripheral glucose utilization, rather than changes in plasma insulin activity, are likely to be involved in this mechanism. At least, this was the conclusion drawn from studies carried out by means of a glucose-controlled insulin and glucose infusion system (GCIGIS) -or artificial pancreas-which delivers short-acting insulin and glucose on demand intravenously. Hypoglycemic reactions in patients being treated with oral anti-diabetic agents, on the other hand, should be regarded primarily as one of the side reactions intrinsic to the mechanism of action of some of these drugs, e.g. sulfonylureas, which act mainly via stimulation of secretion of endogenous insulin reserves not responding properly to postprandial blood glucose increments. In the case of glibenclamide, at least partial resensitization of the defective glucose receptor of the beta-cell also becomes operative. A higher incidence of a characteristic type of hypoglycemic reaction was observed soon after glibenclamide therapy was introduced. Better understanding of the drug and dissemination of the information about it to doctors and patients has reduced the number of hypoglycemic reactions caused by glibenclamide to the same proportions as for other sulfonylureas. Hypoglyoemia following therapeutic hypophysectomy retains its position as one of the main hazards of this heroic therapy.

Adenoma, Islet Cell↗
PubMed1976

Calcitonin-biochemistry and physiology.

Calcitonin is still a mysterious protein hormone. Secreted by the C-cell in ultimobranchial body or thyroid glands, it seems to act as a hypocalcemic antagonist against parathyroid hormone by inhibiting osteolysis. This concept which was developed especially in small mammals like the rat, does not entirely fit the results gained from other species: in fish, CT levels change in connection with the reproductive cycle in the female, in amphibians, buffering capacity of the organism is bound to the ultimobranchial body, and in birds, sexual development in the male is accompanied by increasing calcitonin levels.

Amphibians↗
PubMed1976

[Interaction between gastrointestinal hormones and endocrine regulation].

The vicinity of several hormone-producing glands as part of the anatomy of the intestinal tract and the resulting interaction has been confirmed by the discovery of hormonal factors of a specifically gastro-intestinal origin. Today we are mainly interested in the interaction between intermediary metabolism and incretory intestinal function; this is characterized by the joint action of conventional glandular hormones such as insulin and pancreatic glucagon as well as by the incretion of diffuse intestinal organs, hormones such as secretin, pancreozymin, motilin, VIP and GIP. The latter are at present subject of active research with the object of discovering their physiological significance be it as tissue hormones or as humoral agents with a "long distance" impact; their role within pathophysiology is also of interest. GIP ("gastric inhibitory peptide"), apart form acting upon the intestinal tract, also causes a marked rise in insulin production; this GIP possibly is the factor responsible for the difference in glucose tolerance following i. v. or oral administration of glucose, something that scientists have been trying to discover for a long time. We have also endeavored to investigate somatostatin. This substance was originally discovered as a hypothalamic factor with inhibitory action on growth hormone secretion; in the meantime, however, cells containing and possibly also producing somatostatin have also been detected in the intestine and particularly in the islets of Langerhans (D-cells). Since somatostatin inhibits insulin secretion and especially glucagon release as well as the exretory functions of the stomach and of the pancreas, the significance of this hormone possibly is that of a tissue hormone with inhibitory action on adjacent cells. As factor inhibiting both endocrine and exocrine secretory processes it would combine these two complexes. The possible therapeutic significance of somatostatin administration to diabetics would lie in the saving of insulin. A third sector of present-day research deals with the interaction between the calcium metabolism and the hormones involved as well as the intestine. We know that patients suffering from primary hyperparathyroidism are prone to contract stomach ulcers and pancreatitis; patients with a gastrinoma and a hyperfunction of the epithelial bodies suffer from a Zollinger-Ellison-sindrome and this again suggests association with endocrine polyadenomatosis (Wermer syndrome). The inhibitory action of the parathormone antagonist calcitonin on the exocrine functions of the intestinal tract, such as the acid secretion of the stomach and the enzyme secretion of the pancreas, have already given rise to some considerations and experiments relative to treatment. It is to be hoped that because of all the joint observations cited above there will be better intergration of research both from the aspect of gastro-enterology and endocrinology. This might hopefully elucidate some of the unresolved problems ranging from basic research to practical application.

Adolescent↗
PubMed1975

The DNA melting transition in aqueous magnesium salt solutions.

The melting transition of the magnesium salt of DNA has been systematically examined in the presence of various types of anions. The addition of ClO4- to a concentration of 3.0 N results in the biphasic optical transition, with the first phase exhibiting rapid reversibility and independence of the DNA concentration. This subtransition, which is interpreted as an intramolecular condensation to a collapsed form of DNA, is followed by a DNA concentration-dependent aggregation reaction. The aggregation can be reversed by increasing the ClO4- concentration to 6.0 N while elevating the temperature to post-transition levels. Alternatively, both the collapse and the aggregation can be prevented by melting in the presence of trichloroacetate, the most strongly chaotropic solvent for DNA which has been reported (K. Hamaguchi and E. P. Geiduschek (1962), J. Am. Chem. Soc. 84, 1329). The forces responsible for mediating both the collapse and the aggregation are superficially similar to those involved in maintaining duplex stability. The collapsed form, in particular, possibly possesses features in common with the condensed structures which can be produced in aqueous solution of certain polymers, such as polyethylene glycol (Lerman, L.S. (1971), Proc. Natl. Acad. Sci. U.S.A. 68, 1886).

Animals↗
PubMed1975

[Parathormone determination with synthetic human parathormone 1-34 (PTH) (author's transl)].

Using synthetic human parathormone 1-34, a radioimmunological method for measuring this hormone fragment was developed which, as the amino-terminal PTH assay, permits the measurement of the concentration gradient in the neighborhood of OTH-secreting tumors. The use of preoperative location diagnosis in primary hyperparathyroidism is demonstrated with some typical cases, especially in revision operations.

Adenoma↗
PubMed1975

[Observations in vitamin D and dihydrotachysterol poisoning].

In three women intoxication with vitamin D or dihydrotachysterol occurred. Two patients died from complications despite successful lowering of the serum calcium, the third died after a pulmonary embolus during hypercalcaemia 5 months after cessation of vitamin D. Correct observation of the narrow therapeutic range of vitamin D preparations appears most important in the treatment of hypoparathyroidism and other indications. Particular attention should be given to the prophylaxis of over dosage. Apart from regular serum calcium estimations instruction of the patient and relatives as to the dangers and symptoms of intoxication is recommended. The issuing of a therapy identity card would meet these requirements.

Aged↗
PubMed1975

Pancreatic enzyme secretion in the conscious rat. Method and application.

1. A method for collecting duodenal juice and gastric content separately, in conscious rats, is described. Metal cannulas were implanted into the stomach fundus. For the main experiment a double lumen tube was inserted through the cannula via the pylorus into the duodenum. 2. The following secretion patterns were observed: a) In the resting state there was a constant flow rate of duodenal volume, bicarbonate, trypsin and amylase. b) Cholinergic stimuli were capable of increasing enzyme secretion as much as fourfold for a period of 30 to 40 min when administered as a single subcutaneous injection. This effect was annulled by atropine. c) Secretin and cholecystokinin-pancreozymin given together in a single injection s.c. or i.v., elicited a similarly strong response. d) Identical ranges of the secretion maxima were found with a tendency to decrease after the first hour, when the hormones were infused either s.c. or i.v. e) Doses from 0.5 to 25 U/100 g b.w. /hr showed identical responses. Doses below 0.2 U/100 g/hr were without effect. 3. Narcosis (pentobarbital) inhibited markedly the resting and stimulated enzyme secretion. 4. The method is suitable for examination of physiological and pharmacological effects on resting and stimulated enzyme secretion of the rat pancreas.

Amylases↗
PubMed1975

The effect of chronic lithium application on the mineral content of rat bone and soft tissues.

Rats were treated with lithium chloride over 6 weeks. During the experiment, determinations of serum calcium, magnesium and phosphorus revealed no changes due to the therapy. Postmortem examinations of liver, skeletal muscle, and femur minerals as well as bone histology showed these organs to be unaffected by lithium application. Only body weight gain was in part increased by lithium.

Animals↗
PubMed1975

The hypercalcaemic syndrome in rats bearing the Walker carcinosarcoma 256.

The strain of Walker carcinosarcoma 256 described induces hypercalcaemia, hyperphosphataemia and hyperuraemia in tumour bearing rats. Changes in calcium and phosphorus excretion are observed as well as accompanying calcification of soft tissue organs and loss of bone calcium. These changes in calcium metabolism disappear after removal of the tumour, so that long-range action of the tumour can be stated. The results are discussed in comparison with three other animal models of tumour dependent hypercalcaemia.

Animals↗