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Biomedical subjects

M Nowak

Publications and source records attributed to M Nowak.

At least 145 records · Page 8Linked to original sources
PubMed1990

Sex-dependent effect of melatonin on the secretory activity of rat and hamster adrenal gland in vitro.

Adrenal quarters from adult male or female hamsters were incubated in the presence of melatonin (10(-7) or 10(-4)M), and cortisol concentration in the incubation medium was assayed by RIA. Melatonin did not change cortisol output by adrenals obtained from the male hamsters, while a slight stimulatory effect was observed in female glands, the lower concentration of melatonin being more effective than the higher one. At both concentrations tested, melatonin notably stimulated corticosterone output by isolated rat adrenocortical cells derived from the males, and lowered corticosterone secretion by the cells obtained from the female glands only at a concentration of 10(-7) M. The lower concentration of melatonin increased ACTH (0.1 mU.ml-1)-stimulated corticosterone output by the cells of male and female rat adrenals. The pineal hormone was ineffective at a concentration of 10(-4) M, as well as in the presence of a higher dose of ACTH (1.0 mU.ml-1). These findings indicate a distinct sex-dependent effect of melatonin on in vitro cortisol and corticosterone production, and demonstrate that the modulatory effect of melatonin of the secretion of steroid hormones is more effective at lower concentrations.

Adrenal Glands↗
PubMed1990

Long-term effects of neuropeptide-Y on the rat adrenal cortex.

Adult female rats, intact or dexamethasone suppressed, were i.p. injected twice a day for 4 consecutive days with 0.5 ug neuropeptide-Y (NPY). In intact rats, NPY lowered serum ACTH and aldosterone levels, and had no effects either on serum and adrenal corticosterone or the morphology of the adrenal cortex. In dexamethasone-treated rats, NPY again decreased serum aldosterone concentration. Moreover, it caused a small but significant drop both in the volume of zona fasciculata cells and the adrenal content of corticosterone. These findings seem to suggest an inhibitory effect of NPY on the function of rat zona glomerulosa and perhaps zona fasciculata.

Adrenal Cortex↗
PubMed1990

The mast cell in health and disease.

The presence of mast cells, often in an activated state or increased numbers, has been noted in various cutaneous disorders. Recent studies suggest that mast cells are of primary importance in these conditions and their presence does not merely represent a secondary event. This review focuses on atopic dermatitis, contact hypersensitivity reactions, bullous pemphigoid, fibrosing conditions, neurofibromatosis, wound healing, polycythemia vera, and psoriasis, in which there is significant evidence to indicate a pathophysiologic role for mast cells.

Animals↗
PubMed1990

Coincident rupture of the scapholunate and lunotriquetral ligaments without perilunate dislocation: pathomechanics and management.

Wrist injuries causing coincident disruptions of the scapholunate and lunotriquetral ligaments commonly result in perilunate dislocations. This article (1) describes our management of eight patients with wrist pain after coincident scapholunate and lunotriquetral ligament disruptions in the absence of perilunate dislocation; and (2) reports the results of biomechanical testing of some of the extrinsic and intrinsic wrist ligament and interprets these data to explain the injury seen clinically. The diagnosis of ligament failure was made on the basis of history, physical examination, arthrography and surgical exploration. Surgical treatment of seven patients consisted of concomitant scapho-trapezio-trapezoid fusion and lunotriquetral fusion. Three of seven patients were free of pain, two had pain only at the extremes of motion, and two required additional surgery. Biomechanical analysis of the scapholunate and lunotriquetral ligaments and two extrinsic wrist ligaments, the radiolunotriquetral and the radioscaphocapitate, confirmed the clinical suspicion that the intrinsic ligaments could be completely disrupted while the extrinsics are only partially injured. Such a scenario could account for the residual stability that prevents the development of perilunate dislocations. Coincident disruption of the scapholunate and lunotriquetral ligaments in the absence of perilunate dislocation is an unusual injury. Treatment with lunotriquetral fusion and scapho-trapezio-trapezoid fusion restored functional use in five of seven wrists while maintaining wrist motion.

Adult↗
PubMed1990

[Health promotion in the framework of the health reform legislation--current perspectives for health insurance and municipalities].

This paper describes the perspectives of health promotion within the framework of the basic laws promulgated as of January 1989 in the Federal Republic of Germany. The initial situation, the intentions of the legislator, the performance criteria and the types of organised health promotion on a regional or county (community) basis are described. The new legislation on health promotion opens up new perspectives for compulsory health insurance bodies and regional (community) bodies. The advantages offered thereby must be made use of. The health insurance bodies can revive the principles of self-administration by taking full advantage of all possibilities of creating health promotion facilities. Community bodies must not only bear costs, they are also centrally responsible for health promotion policies to be enforced in their respective regions by organising cooperation between the individual persons and institutions who can regionally act as health policy promoters, and they are expected to bring about a general consensus on health promotion procedures.

Germany, West↗
PubMed1990

Sex differences in adrenocortical structure and function. XXVIII. ACTH and corticosterone in intact, gonadectomised and gonadal hormone replaced rats.

Plasma ACTH and corticosterone (B) concentration, ACTH content in the anterior pituitary gland and B content in the adrenals were measured in intact, gonadectomised and testosterone or estradiol replaced rats. Plasma ACTH and B levels and adrenal B content were higher in female than male rats. Neither orchiectomy nor testosterone replacement had an effect on plasma ACTH and B concentration. Orchiectomy did not affect adrenal B content and decreased pituitary ACTH while testosterone significantly lowered ACTH and B content in studied glands. On the other hand ovariectomy did not change pituitary ACTH and adrenal B content and notably lowered concentrations of these hormones in the blood. Estradiol replacement resulted in an increase in plasma ACTH and B concentrations, an effect accompanied by a marked drop in pituitary ACTH and an increase in adrenal B. These findings indicate the distinct sex differences in basal plasma ACTH and B concentrations with higher values in female rats, an effect dependent on the stimulatory action of estradiol on pituitary-adrenocortical axis.

Adrenal Cortex↗
PubMed1989

Error thresholds of replication in finite populations mutation frequencies and the onset of Muller's ratchet.

The occurrence of thresholds for error propagation in asexually replicating populations is investigated by means of a simple birth and death model as well as by numerical simulation. Previous results derived for infinite population sizes are extended to finite populations. Here, replication has to be more accurate than in infinitely large populations because the master sequence can be lost not only by accumulation of errors--similar to the loss of wildtype through the operation of Muller's ratchet--but also by natural fluctuations. An analytical expression is given which allows straight computation of highly accurate values of error thresholds. The error threshold can be expanded in a power series of the reciprocal square root of the population size and thus increases with 1 square root of N in sufficiently large populations.

Computer Simulation↗
PubMed1989

Oscillations in the evolution of reciprocity.

A game-theoretical analysis of the Iterated Prisoner's Dilemma shows that the evolution of ensembles of stochastic strategies displays a dynamics of high complexity and unpredictability.

Game Theory↗
PubMed1989

Gestational changes in hamster adrenal cortex: morphometric and ultrastructural stereologic studies.

In the hamster, the weight of the adrenal glands increases during the course of gestation, with the highest value at day 5. In comparison to non-pregnant control animals, there were no changes in the volume of the zona glomerulosa (ZG) and zona fasciculata (ZF), while the volume of the zona reticularis (ZR) increased notably. The average volume of ZG-cells rose at day 5 of pregnancy and thereafter gradually decreased to that of control hamsters. A marked drop in the volume of ZF-cells was seen at days 5 and 10 of pregnancy, whereas at day 15 the cells were larger than in controls. At day 5 of pregnancy, a conspicuous increase in the cell volume was found in ZR, followed by lower values at day 10 and again higher than in control hamsters at day 15. The total number of parenchymal cells in hamster adrenal cortex increased at day 10 of gestation, then underwent a marked decrease, reaching the control value at the final day of pregnancy; this drop was mainly due to a reduction in the number of ZF-cells. The changes in the cell volume were paralleled by rather proportional changes in the volume of the mitochondrial compartment and in the quantity of smooth endoplasmic reticulum. The volume of the lipid-droplet compartment significantly rose in the course of gestation in both ZF- and ZR-cells. The cortisol output by adrenal homogenates gradually decreased during pregnancy.

Adrenal Cortex↗
PubMed1989

Studies on the compensatory growth of the adrenal cortex of the male hamster after unilateral adrenalectomy.

The aim of the study was to investigate the cellular aspects of compensatory growth of the adrenal cortex of male hamster after unilateral adrenalectomy. Relative right adrenal gland weight was higher at 24 h after hemiadrenalectomy with no differences--if compared with sham operated hamsters--at 12, 48, 96 and 120 h. In vitro 3H-thymidine incorporation per mg of adrenal after 12 h was higher and 120 h lower in monoadrenalectomised male hamsters than in sham operated animals with no differences in the remaining time-points studied. If 3H-thymidine incorporation was expressed per entire gland, only 120 h after surgery the uptake was lower than in sham operated animals. Five days after hemiadrenalectomy an increase in the average volume of the zona fasciculata cell and no change in the glomerulosa and reticularis zones were observed. At that day solitary adrenal cortex contained similar number of parenchymal cells as the right adrenal gland of sham operated animals. Thus, hemiadrenalectomy in the male hamster leads to a prompt proliferative response of the contralateral gland at 12 h after surgery, followed by decreased proliferative activity at 120 h after surgery. Monoadrenalectomy increased average volume of the zona fasciculata cell and did not change the total number of parenchymal cells in the gland if compared with sham operated animals.

Adrenal Cortex↗
PubMed1989

The radiological examination of the pancreas harvested for transplantation.

The radiological examination of the pancreatic arterial blood supply was performed to show the presence of the arterial variability. 40 arteriograms of pancreatic vessels were made. The research confirmed the subsistence of the arterial variability concerning the dorsal pancreatic artery in particular. The importance of the previous arteriography in donor, before harvesting the pancreatic graft, was unterlined.

Angiography↗
PubMed1989

[Incidence of abnormalities following the use of hormonal contraceptives].

In order to get evidence about the incidence of malformations as because of intrauterine exposition of steroids as after cessation of hormonal contraception in dependence on the time interval between the last intake of hormonale contraceptives (h.c.) and on different pills 5,866 pregnant women have been entered into a case-control-study. 2,834 pregnant women had taken h.c. during pregnancy or got pregnant within 6 menstrual cycles after discontinuation of pills (= cases). For control the data of 3,032 pregnant women were examined. These one had never taken pills or their pregnancy occurred after 7 menstrual cycles after cessation of pill ingestion. Perinatal mortality, Apgar-score (5 min) and incidence of twins were not different in cases and controls. The incidence of malformations was significant (p less than or equal to 0.01) higher in controls than in cases. It depended on age in form of an increase with rising age. The incidence of malformations in both groups increased significantly (p less than or equal to 0.01) with a rising cigarette consumption during pregnancy. The results of this study suggest that smoking regarding malformations represents a higher risk than the intake of h.c.

Abnormalities, Drug-Induced↗
PubMed1988

Studies on hypothalamo-pituitary corticoliberin system. V. The effects of gonadectomy and sex hormones on plasma ACTH and on the reactivity of the anterior pituitary gland to CRF.

The aim of the study was to investigate the effects of gonadectomy and sex hormones on responsiveness of anterior pituitary slices to synthetic CRF and on plasma ACTH level in male and female control, gonadectomised and testosterone or estradiol replaced rats. In animals of both sexes neither gonadectomy nor sex hormone replacement had an effect on plasma level of radioimmunoassayable ACTH. Adenohypophyseal ACTH output in vitro in response to CRF was unchanged by orchiectomy and lowered after testosterone replacement. Moreover, neither ovariectomy nor estradiol replacement had an effect on ACTH output by the entire adenohypophysis. Thus, since there were no apparent changes in plasma ACTH concentration among intact, gonadectomised and testosterone or estradiol replaced male and female rats as well as in responsiveness of the gland to CRF it seems that sex difference in the adrenocortical structure and function depends on action of sex hormones on adrenal and/or liver than on ACTH release on hypothalamic or pituitary level.

Adrenocorticotropic Hormone↗