Biomedical subjects

U Drews

Publications and source records attributed to U Drews.

At least 37 records · Page 2Linked to original sources

PubMed1992

[Sleep disorders: strategies for managing conflict by insomnia patients].

The investigation compares 136 insomniacs with 102 healthy controls with respect to their coping strategies. Coping strategies are evaluated with the questionnaire FKBS. This questionnaire measures 5 different coping strategies: TAS--turning against subject; TAO--turning against object; REV--reversal; PRN--prinzipialisation; PRO projection. Insomniacs seem to react less aggressive than healthy controls. They also show less projections, i.e. they do not believe in a hostile intention of a situation or a counterpart. These differences could be shown on the level of behaviour as well as experience. With the personality traits of the FPI (Freiburger Persönlichkeitsinventar FPI-R) there are some significant correlations. Finally there exists also a correlation between the strategy TAS and the incidence and intensity of depressive symptoms (i.e. state-variabels).

Adaptation, Psychological↗

PubMed1991

Distribution of estrogen target sites in the 2-day-old mouse forebrain and pituitary gland during the 'critical period' of sexual differentiation.

The present study provides a detailed anatomical description of estrogen target cells in the mouse forebrain and pituitary gland during the sexual imprinting stage of the brain. Six 2-day-old mice (3 males and 3 females) were s.c. injected with 16 alpha-[125I]iodo-11 beta-methoxy-17 beta-estradiol ([125I]MIE2) and two additional mice (one male and one female) were s.c. injected with 1000x unlabeled 17 beta-estradiol 1 h before [125I]MIE2 to check the specificity of estradiol binding. Two hours after injection the mice were decapitated, the brains dissected, frozen sectioned, and processed for thaw mount autoradiography. The highest intensity of nuclear labeling was observed in the preoptic-anterior hypothalamic area, amygdala and cortex entorhinalis. Strong labeling was present in the cerebral cortex and moderate to strong labeling in the lateral septum, bed nucleus of stria terminalis and pituitary gland. Weak to moderate labeling was observed in the bulbus olfactorius, circumventricular organs, basal ganglia, ventral striatum, thalamus, hippocampus and pineal gland. No sex differences were observed in the intensity of labeling and distribution of the estrogen target sites. The topographic distributions of estrogen-concentrating cells in the hypothalamus of the 2-day-old mouse forebrain was similar to the adult pattern but differed prominently in the cerebral cortex, entorhinal cortex and thalamus: the cerebral cortex showed an extensive and intensive labeling, the intensity of labeling in the entorhinal cortex greatly exceeded that observed in the adult and the nucleus anterior medialis thalami was distinctly labeled.

Animals↗

PubMed1991

Chick embryo muscarinic and purinergic receptors activate cytosolic Ca2+ via phosphatidylinositol metabolism.

In dissociated cells from chick embryos or from chick limb buds, acetylcholine (ACh) induced an increase in cellular levels of inositol 1,4,5-trisphosphate (Ins-P3) and of inositol 1,3,4,5-tetrakisphosphate (Ins-P4). The concentration of Ins-P3 was enhanced transiently, whereas the level of Ins-P4 remained elevated for at least 20 min after addition of ACh. In most cases the increase in Ins-P4 levels was more pronounced than that of Ins-P3 levels. The inhibition of the ACh-induced inositol-phosphate response by atropine (half-maximal inhibition at 10 nM) indicates the involvement of muscarinic receptors, which in chick embryo cells induce a transient rise and a following persistent elevation of cytosolic Ca2+ activity (G. Oettling et al. (1989) J. Dev. Physiol. 12, 85-94). Adenosine 5'-triphosphate (ATP) elicited a similar transient rise in cytosolic Ca2+ activity, however, without a subsequent plateau. ATP also caused an increase in inositol-oligophosphate levels. Thus, both muscarinic and purinergic receptors in chick embryo cells are coupled to phospholipase C. The enzymatically formed Ins-P3 mediates the release of Ca2+ from internal stores. The Ca2+ signal could be involved in embryonic cell migration during morphogenesis.

Acetylcholine↗

PubMed1990

Vasoactive intestinal polypeptide (VIP) induces calcium mobilization in the human neuroblastoma cell line SK-N-SH.

Release of catecholamines, a Ca2(+)-dependent process, is the most useful biochemical marker in the diagnosis of neuroblastoma. Unfortunately, its stimulus is still unknown. We found that vasoactive intestinal polypeptide (VIP), in addition to acetylcholine and muscarine (but not nicotine), causes elevation of the cytoplasmic Ca2(+)-concentration in the highly differentiated human neuroblastoma cell line SK-N-SH, with or without the presence of extracellular Ca2+. Additionally, VIP was detected in SK-N-SH cells (0.65 ng/10(6) cells). Based on these observations and the fact that neuroblastoma is not innervated in vivo, we hypothesize that in this tumor VIP is responsible for Ca2(+)-dependent release of catecholamines in an autocrine or paracrine fashion.

Acetylcholine↗

PubMed1990

Contraction wave in the chick blastoderm induced by muscarinic stimulation.

The mechanism of excitation contraction coupling during morphogenetic movements is unknown. We describe a contraction wave in the chick blastoderm after muscarinic stimulation, which indicates that an autocrine cholinergic mechanism might be involved in the induction of morphogenetic movements during embryogenesis. Chick blastoderms were explanted in a modified new culture and the cellular movements were recorded by time lapse video filming. Perfusion with acetylcholine or carbachol induced a contraction wave in the blastoderm which started in the periphery at the point of entrance of the drug, and proceeded within 8-10 min through the area pellucida to the opposite side of the blastoderm. Perfusion with the muscarinic antagonist pilocarpine in turn induced relaxation. Atropine inhibited the effect of the agonists acetylcholine and carbachol. From earlier studies we know that in the chick embryo a muscarinic system is present, the expression of which correlates with morphogenetic movements. The induction of a contraction wave in the chick blastoderm by muscarinic agonists supports our hypothesis that embryonic cell movements might be regulated via muscarinic receptors.

Acetylcholine↗

PubMed1989

Differential nuclear binding of [3H]testosterone and its metabolites to androgen and estrogen receptors in brain, pituitary, heart, kidney and accessory sex glands of the mouse: an autoradiographic study.

Nuclear binding of [3H]testosterone ([3H]T) was studied by autoradiography in brain and peripheral tissues of normal male mice and androgen receptor (AR) deficient Tfm (testicular feminized) mice at various time points after injection. All tissues examined contain AR and estrogen receptors (ER). Nuclear binding (accumulation of radioactive hormone) was characterized by competition with excess of dihydrotestosterone (DHT) or estradiol (E2) and by inhibition of aromatization (AI). 2 h after injection of [3H]T, nuclear binding is found in certain regions of the forebrain of male and Tfm mice, but only in area postrema of hindbrain and in accessory sex glands of males. In pituitary, heart and kidney no nuclear binding is observed. In brain, except for area postrema, binding is inhibited by competition with E2 or by AI. DHT has no effect. This indicates predominant binding to ER. In the area postrema and in accessory sex glands binding is inhibited by DHT but not by E2, indicating binding only to AR. After [3H]T together with E2 or AI, additional nuclear binding is found in certain regions of the brain and in pituitary, unlabeled after [3H]T alone and after [3H]T with DHT. It suggests binding to AR which becomes detectable by an increased amount of androgen available for AR. Up to 1 h after [3H]T in the brain, binding is detectable at more sites than after 2 h. This additional binding is not suppressible by E2, indicating binding to AR. Since this additional binding is found only within the first hour after injection, a difference in binding to AR between brain and accessory sex glands after [3H]T is suggested.

Animals↗

PubMed1989

No evidence for aromatization of [3H]testosterone in oestrogen receptor containing cells of the epididymis.

Oestrogen receptors are found in the principal cells of the caput and in apical and clear cells of the epididymis of the mouse. The distribution pattern of oestrogen receptors is different from that of androgen receptors and suggests a physiological role for oestrogens in the epididymis. We examined by competition experiments and thaw-mount autoradiography to see whether aromatization of [3H]testosterone is the source of oestrogens in the epididymis. After injection of [3H]testosterone we found the same labeling pattern as after non-aromatizable [3H]dihydrotestosterone. In particular, apical and clear cells showed a low or no nuclear concentration of radioactivity as with [3H]dihydrotestosterone. Competition with oestradiol had no effect on the binding pattern of [3H]testosterone in the epididymis in contrast to its effects in the brain of the same animals. Competition with dihydrotestosterone abolished labeling in contrast to the brain, where no effect was observed. Thus no aromatization of [3H]testosterone to oestrogens but conversion to dihydrotestosterone seems to occur in the epididymis.

Animals↗

PubMed1989

An embryonic Ca++ mobilizing muscarinic system in the chick embryo heart.

In the embryonic and in the adult heart muscarinic stimulation reduces the heart rate. Here we demonstrate that in the embryonic heart an additional muscarinic system is present, which is characterized by Ca++ mobilization and corresponds to the embryonic muscarinic system in other organ anlagen. In suspensions of embryonic chick heart cells we measured release of Ca++ from intracellular stores and influx of extracellular Ca++ with fura-2 and chlorotetracycline after muscarinic stimulation and determined the [3H]quinuclidinylbenzilate binding sites. We observed intense Ca++ mobilization at day 4, weaker reactions between day 4.5 and 11, and no Ca++ response at day 13. The pharmacological profile was identical to the profile of Ca++ mobilization in cells from other embryonic tissues in which the general embryonic muscarinic system is expressed. In parallel, we studied the effect of muscarinic agonists and antagonists on the heart rate of isolated embryonic hearts at day 4 and 5 in a perfusion chamber. Oxotremorine and bethanechol being antagonists or weak partial agonists in Ca++ mobilization, behaved as full agonists in frequency regulation. Thus, the pharmacological profile of the transient embryonic muscarinic system was different from that of the definitive adult form.

Animals↗

PubMed1988

Muscarinic receptor-mediated intracellular Ca2+ mobilization in embryonic chick heart cells.

Activation of muscarinic receptors of heart cells elevates the intracellular Ca2+ concentration. The increase is considered to be due to influx of extracellular Ca2+. We show that intracellular Ca2+ mobilization is involved. Cell suspensions prepared from hearts of 6-day-old chick embryos were loaded with the fluorescent Ca2+ chelator chlortetracycline. Muscarinic stimulation induces a dose-dependent fluorescence decrease (ED50 = 2.6 x 10(-6) M) indicating intracellular Ca2+ mobilization.

Acetylcholine↗

PubMed1988

Androgen receptor-deficient Tfm cells in the mosaic epididymis of sex-reversed mice heterozygous for Tfm: an autoradiographic study with [3H]-dihydrotestosterone and [3H]-estradiol.

Testicular feminization (Tfm) in the mouse is characterized by androgen insensitivity of the target cells. We describe the presence of androgen-insensitive Tfm cells in the epididymis of mosaic mice produced by converting female carriers of the Tfm mutation (XTfm/X+) to males via the sex reversal factor (Sxr). The mosaic arises by random X-inactivation. In the epididymal duct, flat undifferentiated Tfm cells are interspersed between high columnar wild-type cells. By thaw-mount autoradiography we show that after injection of [3H]dihydrotestosterone, radioactivity is concentrated in the nuclei of high columnar wild-type cells, whereas the nuclei of the low cuboid Tfm cells remain free of nuclear radioactivity. After injection of [3H]estradiol, both Tfm and wild-type cells show nuclear labeling. Our observations demonstrate that Tfm cells in the mosaic epididymis selectively lack nuclear dihydrotestosterone-binding sites, whereas estradiol-binding sites are intact.

Androgen-Insensitivity Syndrome↗

PubMed1988

Intersex mice composed of androgen insensitive Tfm and wild-type cells analysed by 3H dihydrotestosterone autoradiography.

The X-linked testicular feminization mutation (Tfm) in the mouse is characterized by an androgen receptor defect. Due to random X-chromosome inactivation, XTfm/X+ heterozygotes are mosaics with respect to Tfm. They are composed of androgen receptor deficient XTfm cells and normal X+ wild-type cells. If Tfm heterozygotes are converted to XX males by the sex reversal factor (Sxr) the mosaicism is expressed. Therefore in sex reversed Tfm heterozygotes (XTfm/X+-Sxr) intersexual sex organs develop. In five intersexes with small male accessory glands and hypospadia and one heavily feminized intersex with vagina and caudally dislocated deferent ducts the mosaic is visualized by 3H-DHT-autoradiography. In the epididymis differentiated wild-type cells show nuclear labeling, whereas undifferentiated Tfm cells are unlabeled. Unlabeled Tfm cells are also encountered in the vesicular glands of the heavily feminized animal, demonstrating that Tfm cells can participate in the formation of male sex glands. The urethral glands of the mosaic animals are composed of unlabeled Tfm lobules exhibiting the female phenotype of the glands, and of labeled wild-type lobules exhibiting the male phenotype. Formation of a vagina and deviation of the deferent ducts is correlated with lack of androgen binding sites in the connective tissue.

Androgens↗

PubMed1988

An in vitro model of gonad differentiation in the chick embryo. Roller cultures in gas permeable biofoil bags.

Embryonic gonads of 6 1/2 to 12 days old chick embryos were enzymatically dissociated. The cell suspensions were cultured in small gas permeable bags of foil (Biofolie Heraeus) in a roller culture apparatus. The cells formed multiple small aggregates, in which sex specific differences developed within two days. In cell suspensions of embryonic testes smooth spheric aggregates formed with well delineated testicular cords in the center and a tunica albuginea-like mesenchymal layer at the outside. Most of the male germ cells were incorporated in the central cords. A number of germ cells were barred from entering the cords by the tunica albuginea-like mesenchymal layer and populated the outer surface of the aggregates. The aggregates of left ovary were irregular in shape and characterized by clusters of germ cells residing in an outer cortical zone. The aggregates of the right ovary, which regresses in vivo, showed poor growth and did not differentiate, thus, indicating that the suppression of right ovary was not removed in culture. In the roller cultures of dissociated embryonic gonads male and female morphogenesis was mimicked in a reproducible manner, so that the system can be used for further experimental studies of gonadal development.

Animals↗

PubMed1988

Expression of the Ca2+ mobilizing muscarinic system in the chick embryo correlates with morphogenesis.

We describe muscarinic receptors and intracellular Ca2+ mobilization after cholinergic stimulation in cell suspensions prepared from chick embryos between day 2 (stage 12/13) and day 13 (stage 40) of development. Cell suspensions are prepared from whole chick embryos and from embryonic hearts, heads or brains, limb buds, and trunks. Muscarinic receptors are measured using [3H]quinuclidinylbenzilate as specific ligand. Intracellular Ca2+ mobilization is determined by changes of chlorotetracycline fluorescence. (1) Considerable amounts of muscarinic receptors are found in all parts of the embryo and at all stages tested. (2) The intracellular Ca2+ response after stimulation by muscarinic agonist shows a peak at day 3-4 (stage 23). (3) The pharmacological profile of the Ca2+ response remains constant during embryonic development and differs from the profiles of most adult systems. (4) The 'embryonic muscarinic system' is uniformly expressed in cells from neural and non-neural tissues. It appears and disappears independently of innervation.

Acetylcholine↗

PubMed1988

Serological H-Y antigen in the female chicken occurs during gonadal differentiation.

In the chicken, serological H-Y antigen is specific for the female sex. Male gonad differentiation can be experimentally influenced by estrogens, resulting in the transient formation of an ovotestis. The sex-inverted gonad becomes positive for H-Y antigen. Therefore, the question arises whether, in normal gonadogenesis also, the female gonad at the indifferent stage, before estrogens are produced, is negative for H-Y antigen. Here we show that this is indeed the case. The female gonad becomes positive for H-Y antigen when the ovary starts its organotypic differentiation at about day 6 1/2 of embryonal development. It is assumed that estrogens are responsible for the occurrence of H-Y antigen. This finding supports the view that H-Y antigen plays a role in primary ovogenesis in the chicken.

Animals↗

PubMed1988

An in vitro model of gonad differentiation in the chicken. Estradiol-induced sex-inversion results in the occurrence of serological H-Y antigen.

Dissociated cells from the gonads and mesonephros of 8-day-old chicken embryos were reorganized in rotation culture. The aggregates obtained from gonadal cells exhibited specific morphologic and histologic sex differences. In the presence of estradiol, aggregates from testicular cells showed characteristics similar to control ovarian aggregates, while in ovarian aggregates under estradiol treatment the female organization became more pronounced. Determination of serological H-Y antigen revealed that male aggregates of gonads and mesonephros were negative for H-Y and those of female embryos were positive for H-Y. Administration of estradiol did not change the H-Y findings in female aggregates. In contrast, in the male, gonadal cultures became H-Y positive while mesonephros cultures remained negative. It is assumed that estradiol induces the occurrence of H-Y antigen in the gonads.

Animals↗

PubMed1986

Sites of aromatization of [3H]testosterone in forebrain of male, female and androgen receptor-deficient Tfm mice: an autoradiographic study.

The distribution of radioactivity after injection of [3H]testosterone was studied in the forebrain of adult mice by thaw-mount autoradiography. Nuclear labeling was high in neurons in the dorsal part of the medial nucleus of the amygdala and in the dorsocaudal part of the bed nucleus of the stria terminalis. Low nuclear uptake occurred in the medial preoptic nucleus, in mediobasal hypothalamic nuclei and in the ventromedial amygdala. Nuclear concentration of radioactivity was not influenced by competition with dihydrotestosterone and was present in androgen receptor deficient Tfm mice. It was totally abolished by competition with estradiol. This indicates that in the brain [3H]testosterone is converted to estrogenic metabolites which bind to estrogen receptors. Nuclear labeling after [3H]testosterone was restricted to a few of the brain nuclei, known to contain estrogen receptors indicating that aromatization occurs only in select regions. The results suggest that testosterone acts on the brain via estrogen receptors.

Amygdala↗

PubMed1986

Embryonic cholinesterase activity during morphogenesis of the mouse genital tract. Light- and electron-microscopic observations.

In the genital tract of male and female mouse embryos cholinesterase activity is described that is independent from innervation. The enzyme activity is localized in the mesenchyme at the junction of Wolffian and Müllerian ducts with the urogenital sinus. During male development prostate buds and vesicular glands grow out into the cholinesterase-active mesenchyme. During female development the active mesenchyme participates in the downgrowth of the vaginal anlage. Ultrastructurally the cholinesterase activity is localized in the perinuclear cisterna and in smooth endoplasmic reticulum of the mesenchymal cells. The enzyme activity disappears with definitive differentiation of the tissue. The embryonic cholinesterase is a component of a primitive muscarinic system. Its relation to the morphogenetic action of testosterone and its possible general functions are discussed.

Animals↗

PubMed1986

Autoradiographic studies with 3H dihydrotestosterone in the brain of sex reversed mice, heterozygous for androgen insensitive testicular feminization (Tfm). A comparison with normal female mice and sex reversed male mice.

Specific binding sites for 3H dihydrotestosterone are demonstrated by autoradiography in brain nuclei of sex reversed mice heterozygous for testicular feminization (Tfm) which are phenotypically intersexes with testes and accessory sex glands that consist of a mosaic of androgen insensitive Tfm cells which lack specific dihydrotestosterone binding and androgen sensitive normal cells. The nuclear group evaluated include: nucleus (n.) septi lateralis, n. interstitialis striae terminalis, n. medialis amygdalae, the hypothalamic n. arcuatus, n. ventromedialis lateralis, n. pre-mammillaris ventralis, n. preopticus medialis, and nuclei of the cranial nerves VII, X, and XII. In the sex reversed males and the female, used as controls, the frequency of neurons with specific DHT binding show a distinct male-female difference in the caudal part of the arcuate nucleus. In the sex reversed Tfm heterozygotes, in all brain nuclei studied, the frequency of labeled neurons is reduced. The extent of reduction of androgen binding in the different brain nuclei varies among as well as within individual sex reversed Tfm heterozygotes, suggesting variations of the ratio of normal to Tfm neurons in sex reversed Tfm heterozygotes. The differentially reduced androgen binding of different brain systems corresponds to a differentially reduced androgen dependent behaviour reported in the literature.

Amygdala↗