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Biomedical subjects

F Nürnberger

Publications and source records attributed to F Nürnberger.

At least 19 recordsLinked to original sources
PubMed1995

Somatostatin-immunoreactive cell in the gastrointestinal tract of the frog Rana esculenta.

The morphology and topographic distribution of somatostatin-immunoreactive cells in the stomach and small intestine of the frog Rana esculenta were studied at the light-microscopic level by the use of the peroxidase-antiperoxidase method. Scattered immunostained cells occurred in all regions of the gastrointestinal tract investigated. In the small intestine, the number of these cells decreased gradually in the oral to anal direction, i.e. from the pyloric (antral) stomach to the entrance into the colon. Most of the immunostained cells possessed thick, short cytoplasmic processes, which did not display a preferential spatial orientation. Other somatostatin-immunoreactive cells, which were exclusively located in the small intestine, gave rise to a single long extension oriented toward the lumen. In both stomach and small intestine, a complete penetration of the epithelial surface by these processes of somatostatin-immunoreactive cells was observed only occasionally. The morphological features of the somatostatin-immunostained cells speak in favor of endocrine, paracrine, and possibly also intraluminal secretory functions of the enteroendocrine somatostatin system in frogs.

Animals↗
PubMed1995

The neuroendocrine system in hibernating mammals: present knowledge and open questions.

The present review describes the distribution and the function-dependent reactivity pattern of those peptidergic and aminergic components of the neuroendocrine system of hibernating mammals that have been studied by histological, pharmacological and physiological techniques. Particular attention has been paid to the intrinsic connectivity of the peptidergic apparatus and its input systems. Since the reactivity patterns of the neuroendocrine system show remarkable fluctuations in relation to the various stages of hibernation and euthermia, these fluctuations have been analyzed with respect to (1) their causative role in the regulation of hibernation and (2) their secondary response to physiological changes during hibernation. The author's investigations described in this review have mainly been performed in European hedgehogs (Erinaceus europaeus), European and golden hamsters (Cricetus cricetus, Mesocricetus auratus), dormice (Glis glis), and in Richardson's and Columbian ground squirrels (Spermophilus richardsonii, Spermophilus columbianus), by the use of light- and electron-microscopic immunocytochemistry and histochemistry, in situ hybridization, radioimmunoassays and stereotaxically guided application techniques. These experiments were also performed in hypothermic animals. The (partially published) results obtained by the author and his associates are reviewed with reference to the body of evidence found in the recent literature. With respect to their reactivity patterns, several neuropeptide and transmitter systems can be regarded as candidates for control systems of hibernation. Neuronal complexes immunoreactive for endogenous opiates, in particular enkephalin, and also for vasopressin, somatostatin, substance P, corticotropin-releasing factor and serotonin are probably involved in the neuroendocrine control of hibernation.

Animals↗
PubMed1995

Distribution and ultrastructure of somatostatin-immunoreactive cells in the pancreas of Rana esculenta.

Apart from a description of the general organization of the endocrine pancreas, the present study is focussed on the distribution and ultrastructural morphology of somatostatin-immunoreactive cells in the pancreas of the frog Rana esculenta. For light-microscopic histochemistry, the peroxidase-antiperoxidase technique was used. For the ultrastructural investigation, we employed the immunogold method. The endocrine pancreas of R. esculenta is composed of numerous islet-like structures, which contain several small somatostatin-immunoreactive cells arranged in the form of clusters. Often, however, single somatostatin cells are randomly distributed among the acinar tissue of the pancreas. These individually arranged elements possess long processes which terminate on exocrine pancreatic cells. The ultrastructural features of somatostatin-immunoreactive cells speak in favor of their endocrine and paracrine functions.

Animals↗
PubMed1994

Effects of illumination and enucleation on substance-P-immunoreactive structures in subcortical visual centers of golden hamster and Wistar rat.

The undecapeptide substance P is found in different entities of the visual system that control eye movement and synchronize endogenous rhythms with the light cycle (i.e., superior colliculus, suprachiasmatic nucleus, intergeniculate leaflet). Immunocytochemical methods were used to compare the reactivity to substance P in the brain of five groups of golden hamsters and two groups of Wistar rats: (1) untreated hamsters kept under 14L:10D and sacrificed at noon; (2) identically maintained animals sacrificed at midnight; (3) enucleated animals kept under control conditions; (4) hamsters kept under constant darkness; (5) hamsters kept under the same conditions as the controls, but intraventricularly injected with colchicine. The results obtained in golden hamsters of groups (1) and (3) were compared with findings in Wistar rats treated accordingly [groups (6) and (7)]. Substance P-immunoreactive perikarya were found in the suprachiasmatic nucleus and superior colliculus of hamsters and Wistar rats. Substance P-immunoreactive nerve fibers were abundant in the hypothalamic area ventral to the paraventricular nucleus, in the intergeniculate leaflet, in some thalamic nuclei, and in the superior colliculus. Immunoreactivity to substance P in the suprachiasmatic nucleus and intergeniculate leaflet did not vary among the experimental groups. However, a conspicuous decrease in reactivity to substance P was observed in the superficial layers of the superior colliculus of enucleated hamsters and rats, compared with all other groups. These results indicate that substance P immunoreactivity in the superior colliculus, but not that in the suprachiasmatic nucleus or intergeniculate leaflet, depends on the integrity of the retinal projection.

Animals↗
PubMed1993

Acute monoblastic leukemia with skin nodules in an adult.

An 18-year-old man had a 3-week history of malaise, a 1-week history of a papular eruption, and increasingly severe multisystem neurologic symptoms. A diagnosis of acute monoblastic leukemia was made. Immunophenotypic characterization of peripheral blood, bone marrow, and cutaneous infiltrates revealed a predominant myelomonocytic phenotype with the coexpression of intercellular adhesion molecule type 1, IgE receptor, terminal deoxynucleotidyl transferase, and some T-cell markers. These findings may have important clinical and pathogenetic implications regarding the biologic and pathologic behavior of the myelomonocytic leukemic cells. They also explain in part the impressive presentation of the disease in the skin.

Adolescent↗
PubMed1993

[Treatment of vitiligo with phenylalanine and UV-A].

Seven patients with generalized vitiligo were treated with 100 mg/kg body weight phenylalanine in combination with UV-A. A 20% repigmentation of the vitiligenous area was achieved in only one patient. Three patients each showed either a sparse follicular repigmentation or no effect at all. Because of the disappointing therapeutic results and possible side effects, we cannot recommend a therapy with phenylalanine and UV-A for vitiligo.

Administration, Oral↗
PubMed1991

The efferent connections of the lateral septal nucleus in the guinea pig: projections to the diencephalon and brainstem.

The anterograde Phaseolus vulgaris-leucoagglutinin (PHA-L) tracing technique was used to determine the distribution of efferent fibers originating in the lateral septal nucleus of the guinea pig. For complementary detection of the chemical identity of the target neurons, double-labeling immunocytochemistry was performed with antibodies to PHA-L and to vasopressin, oxytocin, vasoactive intestinal polypeptide, serotonin or dopamine beta-hydroxylase, respectively. The hypothalamus received the majority of the PHA-L-stained septofugal fibers. Here, a specific topography was observed. (1) The medial and lateral preoptic area, (2) the anterior, lateral, dorsal, posterior hypothalamic and retrochiasmatic area, (3) the supraoptic, paraventricular, suprachiasmatic, dorsomedial, caudal ventromedial and arcuate nuclei, and (4) the tuberomammillary, medial and lateral supramammillary, dorsal and ventral premammillary nuclei always contained PHA-L-labeled fibers. The rostral portion of the ventromedial nucleus and the medial and lateral mammillary nucleus only occasionally showed weak terminal labeling. In other diencephalic areas, termination of PHA-L-labeled fibers was observed in the epithalamus and the nuclei of the midline region of the thalamus. In the mesencephalon, terminal varicosities occurred in the ventral tegmental area, interfascicular and interpeduncular nucleus, and periaqueductal gray. In addition, the dorsal and medial raphe nuclei of the metencephalon, together with the locus coeruleus and the dorsal tegmental nucleus, received lateral septal efferents.

Animals↗
PubMed1991

The efferent connections of the lateral septal nucleus in the guinea pig: intrinsic connectivity of the septum and projections to other telencephalic areas.

The distribution of efferent fibers originating in the lateral septal nucleus was investigated in guinea pigs by means of anterograde tracing with Phaseolus vulgaris-leucoagglutinin (PHA-L). Special emphasis was placed on the intraseptal fiber systems. The fibers originating from the different subnuclei of the lateral septal nucleus formed massive horizontal connections in the rostrocaudal axis. Projections to the contralateral, congruent subnuclei were also detected. In the medial septum/diagonal band of Broca complex the largest number of PHA-L-stained fibers was found after application of the tracer into the dorsal subnucleus of the lateral septal nucleus; the density of the efferent fibers decreased progressively after injection into the intermediate or ventral subnuclei. In all cases the diagonal band contained a much higher number of efferent fibers from the lateral septal nucleus than from the medial septal nucleus. In the medial septal nucleus, terminal labeling was generally sparse. Other telencephalic areas (organum vasculosum of the lamina terminalis, nucleus accumbens, bed nucleus of the stria terminalis, amygdala, hippocampal complex, and other cortical areas) contained varying numbers of labeled projections. In double-labeling experiments, a close spatial relationship between PHA-L-stained fibers and vasoactive intestinal polypeptide-immunoreactive perikarya was observed in several of these target areas.

Animals↗
PubMed1991

Incidence and mortality of malignant melanoma in Berlin (West) from 1980 to 1986.

Newly diagnosed melanomas were investigated utilizing the histological reports from the 4 Departments of dermatology as well as from 3 Departments of pathology in Berlin (West) during the years 1980-86. The study included 960 melanomas and documented the histological features, age, gender and nationality of the patients involved. 936 patients were Germans (379 males, 557 females), and the mean age-adjusted incidence rate (for the European standard population) was 7.1 cases per 100,000 inhabitants and year for both genders with an increase between 1980-81 and 1985-86 in men from 6.0 to 9.8 and in women from 5.8 to 7.8/100,000 and year. Thus a 49% increase in incidence was observed for both genders combined during a 5-year period. In this study, a preponderance of male incidence rates was observed for the first time in Germany. Interestingly, the age-adjusted incidence rate for the Turkish population, which is the largest foreign population with more than 100,000 inhabitants in Berlin, was only 1.3/100,000 and year. 162 men and 145 women died of melanoma in the time period examined. From 1980-81 to 1985-86, the age-adjusted mortality rate changed from 3.5 to 2.6 for men and from 1.2 to 1.6 for women per 100,000 and year, thus revealing a slight decrease in mortality for both genders combined.

Adult↗
PubMed1990

Changes in physiological and neuroendocrine properties during thermal adaptation of golden hamsters (Mesocricetus auratus).

Golden hamsters raised at 22 degrees C were adapted in the early summer for 3 weeks to either 28 degrees C or 5 degrees C. To achieve profound changes the photoperiod was also shortened from 14 h to 11 h during adaptation to cold. During the investigation body weight, food consumption, water intake, urine production, and osmolality, as well as secreted amounts of noradrenaline (NA) and dopamine (DA), were recorded in each animal before, during, and after the adaptation period. In another group of golden hamsters the brains were processed for immunocytochemical detection of arginine-vasopressin (AVP) and corticotropin releasing factor (CRF) in the third week of adaptation to a cold or warm environment. In warm-adapted animals food and water consumption and urine production remained unchanged or were only slightly reduced. NA and DA secretion were reduced by 50%. The AVP-immunoreactivity reflected an anti-diuretic state in these animals. In fibers influencing the adrenal axis, AVP-immunoreactivity was weak compared to CRF fibers. Food and water consumption, urine production, and DA secretion increased two-fold during cold adaptation. Daily secreted amounts of NA increased nine-fold. AVP-immunoreactivity was weak in projections to the neurohypophysis. Fibers influencing the adrenal axis, however, displayed strong AVP-immunoreactivity in comparison to that of CRF. The immunocytochemically determined patterns of AVP and CRF distribution indicated an activation of the osmoregulative axis in the warm-adapted animals and of the adrenal axis in the cold-adapted golden hamsters.

Adaptation, Physiological↗
PubMed1990

An improved silver staining technique as an alternative nuclear or combined nuclear nerve-fiber impregnation for comparative light-, secondary and backscattered electron scanning microscopy.

Slices of rat brain were stained by a new silver impregnation technique. This method takes into consideration the pH-dependent differences of silver stain affinity of nerve tissues and can be used alternatively as a stain for nuclei or as a method for combined demonstration of nuclei nerves fibers. The slices were studied at the light microscopical (LM) level and subsequently with a scanning electron microscope, using secondary (SSEM = classical SEM), and backscattered electron detectors (BSEM). This new silver staining technique offers the opportunity of comparative studies with regard to different information acquired with LM, SSEM and BSEM. The described method allows to distinguish between nervous and glial tissue without necessarily damaging the glial tissue surrounding the nerve fibers. Specifically, scanning electron microscopy with backscattered electron detector of in situ preparations provides a higher contrast of stained and unstained tissue and increased depth of focus as compared to secondary electron detectors.

Animals↗
PubMed1990

Columnar arrangement of lumbar motoneurons innervating a pair of antagonistically acting leg muscles in the rat.

Various problems concerning the physiology of muscular units depend on the exact localization of motoneurons innervating antagonistically acting muscles. The present communication is focussed on the distribution of motoneurons innervating the gastrocnemius (GC) and tibialis anterior (TA) muscles. After injection of horseradish peroxidase (HRP) into these muscles and a survival time ensuring sufficient retrograde transport, the number of motoneurons, their segmental distribution, the mean area covered the labeled cells and the mean diameter of their somata were determined. After injections into the GC-muscle, 129 +/- 6 labeled perikarya were found, and following injections into the TA-muscle, 120 +/- 9 motoneurons were marked with HRP. The motoneurons of both muscles were distributed in spinal cord segments L4-5-6; however, the GC-neurons accumulated in segments L5-6 (approximately 94%) and the TA-neurons in L4-5 (approximately 95%). Although the motoneurons innervating both muscles were located in a rather similar area of the ventral column, i.e. its dorsolateral portion as judged from transverse sections, the GC-motoneurons were situated ventrolaterally to the TA-motoneurons. The measurement of the area of the somata and the mean soma diameter did not reveal any conspicuous differences between both pools of motoneurons. An unimodal distribution pattern of these parameters suggests a broad overlap in the size of alpha-, beta-, and gamma-motoneurons.

Animals↗
PubMed1989

Pattern of afferents to the lateral septum in the guinea pig.

The septal region represents an important telencephalic center integrating neuronal activity of cortical areas with autonomous processes. To support the functional analysis of this brain area in the guinea pig, the afferent connections to the lateral septal nucleus were investigated by the use of iontophoretically applied horseradish peroxidase (HRP). Retrogradely labeled perikarya were located in telencephalic, diencephalic, mesencephalic and metencephalic sites. The subnuclei of the lateral septum (pars dorsalis, intermedia, ventralis, posterior) receive afferents from the (i) medial septal nucleus, diagonal band of Broca (pars horizontalis and pars ventralis), and the principal nucleus of the stria terminalis, the hippocampus, and amygdala (nucleus medialis): (ii) the medial habenular nucleus, and the para- (peri-) ventricular, parataenial and reuniens nuclei of the thalamus; the anterior, lateral and posterior hypothalamic areas (in particular, the medial and lateral preoptic, suprachiasmatic, periventricular, paraventricular, arcuate, premammillary, and supramammillary nuclei; (iii) the periaquaeductal grey, ventral tegmental area, nucleus interfascicularis, nucleus reticularis linearis, central linear nucleus, interpeduncular nucleus; (iv) dorsal and medial raphe complex, and locus coeruleus. Each subnucleus of the lateral septum displays an individual, differing pattern of afferents from the above-described regions. Based on a double-labeling method, the vasopressinergic and serotonergic afferents to the lateral septum were found to originate in the nucleus paraventricularis hypothalami and the raphe nuclei, respectively.

Animals↗
PubMed1989

The serotonin-immunoreactive system of the suprachiasmatic nucleus in the hibernating ground squirrel, Spermophilus richardsonii.

In the suprachiasmatic nucleus (NSC) of hibernating and non-hibernating ground squirrels, the distribution of serotonin-immunoreactive (5HT-IR) fibers was studied by the use of the peroxidase-antiperoxidase technique. The cytology of perikarya giving rise to these suprachiasmatic 5HT-IR fibers was investigated in the anterior raphe nuclei. Differences in the immunoreactivity of suprachiasmatic fibers between hibernating and non-hibernating ground squirrels were determined by digital image analysis. The cellular activity was determined by digital image analysis. The cellular activity was determined densitometrically after RNA-staining in anterior raphe neurons and suprachiasmatic perikarya. Abundant 5HT-IR fibers were observed in the medial and ventromedial portions of the NSC. Frequently, the fibers were found in close contact with perikarya of suprachiasmatic neurons. The central portion of the nucleus and the surrounding hypothalamic areas contained only a few scattered 5HT-IR fibers. Inside the raphe nuclei, 5HT-IR fibers and perikarya formed a dense network. In hibernating ground squirrels, the immunoreactivity to serotonin was approximately 45% higher than in non-hibernating controls. This difference is in accordance with signs of higher neuronal activity (40% higher RNA-content, 20% larger cell nuclei) in 5HT-IR perikarya of the raphe nucleus and the persisting activity of the NSC during hibernation; the activity of other brain regions dropped conspicuously in torpid animals.

Animals↗