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Biomedical subjects

H Schwarz

Publications and source records attributed to H Schwarz.

At least 109 records · Page 6Linked to original sources
PubMed1993

A receptor induced by lymphocyte activation (ILA): a new member of the human nerve-growth-factor/tumor-necrosis-factor receptor family.

A 1.4-kb full-length cDNA was isolated from a library constructed from activated human T-cell leukemia virus type 1-transformed human T-lymphocytes. Sequence analysis identified this cDNA as a new member of the human nerve-growth-factor receptor/tumor-necrosis-factor receptor family and as the potential human homologue of the murine sequence, 4-1BB. The gene encodes three cysteine-rich motifs in the extracellular domain which are characteristic of this receptor family, a transmembrane region and a short N-terminal cytoplasmic portion which contains potential phosphorylation sites.

Amino Acid Sequence↗
PubMed1993

Serotonin induces progesterone release from human granulosa cells in a superfused granulosa cell system.

The dynamics of the release of progesterone (P) by human granulosa cells (GCs) was investigated in a granulosa cell-superfusion system using serotonin (5-HT), propranolol (PR), or mianserin (MI). Granulosa cells were obtained from 8 women undergoing in-vitro fertilization and embryo transfer. Progesterone was measured using radioimmunoassay. Serotonin (100 pMol) induced P release from human GCs. This effect was specifically blocked by 100 pMol MI whilst 100 pMol PR was ineffective in this condition. The results suggest, that the superfused GC system is suitable for studying the dynamics of steroid secretion by human GCs.

Adult↗
PubMed1993

The modulatory effect of catecholamines on gonadotropin-stimulated granulosa cell steroid secretion.

The physiological role of catecholamines in the regulation of gonadotropin stimulated ovarian steroid secretion is unclear. This study was undertaken to investigate the influence of catecholamines on gonadotropin stimulated cultured human granulosa cells under serum-free conditions. Adrenaline and dopamine had no influence on LH stimulated estradiol production. Noradrenaline, however inhibited it (P < 0.01). FSH response was enhanced by adrenaline and decreased by dopamine and noradrenaline (P < 0.05). Noradrenaline and adrenaline decreased the progesterone stimulating effect of LH (P < 0.01), but dopamine had no influence. Adrenaline treatment enhanced, dopamine and noradrenaline decreased slightly the progesterone production of FSH treated granulosa cells (P < 0.05). The results suggest that catecholamines modulate the stimulating effect of gonadotropins.

Catecholamines↗
PubMed1993

Relationship between the monoamine, progesterone and estradiol content in follicular fluid of preovulatory graafian follicles after superovulation treatment.

We measured the progesterone, estradiol (E2), serotonin (5-HT), noradrenaline (NA) and dopamine (DA) contents of follicular fluid (FF) samples obtained from 35 patients undergoing in vitro fertilization and embryo transfer. Progesterone and E2 were determined by radioimmunoassay, and monoamines were measured by a spectrofluorimetric method. Significantly higher progesterone and NA levels were found (p < 0.01) in FF from cycles in which the oocyte cleaved and resulted in pregnancy compared to FF containing uncleaved oocytes. NA and DA contents were significantly higher in FF from cycles resulting in pregnancy than in FF containing cleaved oocytes not resulting in pregnancy (p < 0.01). There were significantly lower NA and 5-HT levels in FF containing uncleaved oocytes compared to the latter group (p < 0.05). Significant positive correlations were found between progesterone and 5-HT (r = 0.67) and between NA and DA (r = 0.93) in the pregnant group; between progesterone and E2 (r = 0.84) in FF containing uncleaved oocytes; between progesterone and E2 (r = 0.71) and between NA and DA (r = 0.62) in FF from cycles in which the oocyte cleaved but did not result in pregnancy. The results suggest that the follicular hormonal changes associated with oocyte maturation may be locally modulated by monoamines.

Biogenic Monoamines↗
PubMed1993

Cholinergic stimulation of progesterone and estradiol secretion by human granulosa cells cultured in serum-free medium.

Cholinergic effects on hormone secretion by human granulosa cells (GCs) are not well characterized. The aim of this study was to explore the direct action of acetylcholine and carbachol on progesterone and estradiol secretion of human GCs cultured in serum-free medium. Granulosa cells were obtained from 26 women undergoing in vitro fertilization and embryo transfer. Progesterone and estradiol production was measured in the presence and absence of acetylcholine, carbachol, or atropine using radioimmunoassays; statistical analysis of the data was performed by ANOVA. Acetylcholine significantly stimulated progesterone secretion by GCs in a dose-related manner. Estradiol secretion was also stimulated by acetylcholine, but this effect did not show dose dependency. Carbachol showed a similar stimulatory effect, but to a lower degree; both effects can be blocked by acetylcholine. The results suggest that cholinergic action on steroid production by human GCs is mediated through the muscarinic route, and cholinergic neurotransmission may have a physiological significance in the intra-ovarian regulatory pathways.

Acetylcholine↗
PubMed1993

The effect of histamine on progesterone and estradiol secretion of human granulosa cells in serum-free culture.

The aim of this study was to explore the direct action of histamine on progesterone and estradiol secretion of human granulosa cells cultured in serum-free medium. Human granulosa cells were isolated from preovulatory follicular fluid aspirated from 17 women (32 +/- 3 years old, mean +/- SD) undergoing in vitro fertilization treatment at the University Women's Hospital of Tübingen. Progesterone and estradiol production was measured in the presence and absence of histamine, terfenadine or cimetidine using radioimmunoassays. Statistical analysis of the data was performed by analysis of variance and Newmann-Keul tests. Histamine stimulated a dose-related increase in estradiol secretion with a maximal stimulatory effect at 10(-3) mol/l. This response was blocked specifically by the H1-receptor antagonist terfenadine. Progesterone production in response to histamine stimulation was independent of dose at the limit of significance. The specific H2-receptor antagonist cimetidine did not block the stimulatory effect of histamine. We suggest that histamine has a direct stimulatory effect on steroid production of granulosa cells mediated via the H1-receptor. This effect may have a physiological role in the regulation of granulosa cell function during the menstrual cycle.

Adult↗
PubMed1992

Activation of an inducible c-FosER fusion protein causes loss of epithelial polarity and triggers epithelial-fibroblastoid cell conversion.

As a novel approach to studying the modulation of the polarized epithelial phenotype, we have expressed c-Fos and c-Myc estrogen receptor fusion proteins (c-FosER and c-MycER) in mammary epithelial cells. The hybrid proteins could be activated by estrogen for defined time periods and after the cells had achieved their fully polarized organization. Activation of c-MycER deregulated proliferation but did not affect epithelial polarity. Short-term activation of c-FosER induced the reversible loss of morphological and functional cell polarity. In contrast, long-term stimulation of c-FosER caused the cells to depolarize irreversibly, to invade collagen gels, and to undergo epithelial-fibroblastoid cell conversion. Our data suggest that Fos proteins are important in modulating the epithelial phenotype both in normal tissue development and in invasive processes.

Animals↗
PubMed1992

[A villous adenoma of the duodenum].

X-ray contrast examination of the upper gastrointestinal tract in a 73-year-old man with nocturnal heartburn demonstrated a constant filling defect in the duodenum. Gastroduodenoscopy revealed a 4 x 3 cm polypoid mucosal change of the duodenal wall adjacent to the pancreas. Histological examination of an endoscopically obtained biopsy showed a tubulovillous adenoma with severe mucosal dysplasia. The affected segment of duodenum was resected. Serial sections showed extensive focal carcinomatous degeneration of an adenoma. The postoperative course was unremarkable. At endoscopy 30 months later, when the patient was free of any symptoms, there was no macroscopic or microscopic evidence of recurrence. Experience so far indicates that villous adenoma of the duodenum should be treated by radical surgery.

Adenoma↗
PubMed1992

The lethal(1)optomotor-blind gene of Drosophila melanogaster is a major organizer of optic lobe development: isolation and characterization of the gene.

The X-chromosomal complementation unit lethal(1)optomotor-blind [l(1)omb] is defined by lack of complementation among over a dozen recessive lethal mutations that map to the omb gene locus. Mutations in l(1)omb also fail to complement viable mutations of three seemingly unrelated functions in this region: bifid (bi), manifesting defective wings, Quadroon (Qd), a semi-dominant mutation expressing abnormal tergite pigmentation, and In(1)ombH31, giving rise to a normal external morphology but with discrete defects in the optic lobes and behavior. The locus encodes a 70-kilobase primary transcript that is spliced into a 6-kilobase mature RNA. cDNAs for this transcript were isolated and sequenced and the derived amino acid sequence was analyzed. Certain features of this sequence suggest that the l(1)omb gene product is a nuclear regulatory protein. The lethal phase of various apparent null mutants was determined and found to occur mainly in the pupal stage. A large proportion of all hemizygous mutant males develop to pharate adults that eclose only rarely but can be rescued from the pupal case. These animals show a severe maldevelopment of the optic lobes. In addition they have only rudimentary wings as well as a Quadroon-like abdominal pigmentation. Thus, in the lethal mutants those parts of the body are affected for which independent viable mutations have been previously described in the omb locus, such as optomotor-blind, bifid, and Quadroon.

Amino Acid Sequence↗
PubMed1992

Transcriptional repression of band 3 and CAII in v-erbA transformed erythroblasts accounts for an important part of the leukaemic phenotype.

The v-erbA oncogene confers two prominent properties on transformed erythroblasts: a block of spontaneous differentiation and tolerance to wide variations in the pH or ionic strength of culture medium. V-erbA acts as a constitutive repressor of erythrocyte-specific gene transcription, arresting the expression of at least three different erythroid genes: the erythrocyte anion transporter (band 3), carbonic anhydrase II (CAII) and delta-aminolevulinate synthase (ALA-S). To test whether or not the v-erbA induced repression of these genes is causally related to the v-erbA induced leukaemic phenotype, we have reintroduced the genes for band 3 or CAII into transformed erythroblasts via retrovirus vectors. We show here that such erythroblasts, expressing v-erbA, require the same narrow range of medium pH and ion concentration for growth as do transformed erythroblasts lacking v-erbA, i.e. the v-erbA induced tolerance to pH variation was abrogated. The v-erbA induced differentiation block, however, remained unaffected by the re-expression of band 3 and was only slightly affected by the re-expression of CAII. Our experiments show that the two v-erbA-related 'erythroblast transformation parameters' are separable: suppression of band 3 and CAII accounts for one parameter (pH/ion tolerance), while the second parameter (differentiation block) must involve v-erbA regulation of a different set of target genes.

5-Aminolevulinate Synthetase↗
PubMed1992

Acupuncture fails to improve treatment outcome in alcoholics.

Fifty-six alcoholics (49 male, 7 female) of lower socioeconomic class attending an outpatient treatment program in Brooklyn, New York were prospectively randomized to one of three treatment group: point-specific acupuncture, sham transdermal stimulation or standard care (control). One third of the subjects reported a history of drug use in addition to alcohol. Results in this small sample showed no significant differences in attendance at Alcoholics Anonymous meetings, number of outpatients sessions attended, number of weeks in either the study or in the outpatient program, number of persons completing treatment or in the number of relapses. It is therefore concluded that in this small racially mixed sample of urban outpatient alcoholics, fixed point-specific standardized acupuncture did not improve outcome. We caution against the routine use of this treatment until more randomized controlled trials demonstrate a beneficial effect.

Acupuncture Points↗
PubMed1992

Iron(III) hydroxamate transport in Escherichia coli K-12: FhuB-mediated membrane association of the FhuC protein and negative complementation of fhuC mutants.

Iron(III) hydroxamate transport across the cytoplasmic membrane is catalyzed by the very hydrophobic FhuB protein and the membrane-associated FhuC protein, which contains typical ATP-binding domains. Interaction between the two proteins was demonstrated by immunoelectron microscopy with anti-FhuC antibodies, which showed FhuB-mediated association of FhuC with the cytoplasmic membrane. In addition, inactive FhuC derivatives carrying single amino acid replacements in the ATP-binding domains suppressed wild-type FhuC transport activity, which arose either from displacement of active FhuC from FhuB by the mutated FhuC derivatives or from the formation of mixed inactive FhuC multimers between wild-type and mutated FhuC proteins. Inactive FhuC derivatives containing internal deletions and insertions showed no phenotypic suppression, indicating conformational alterations that rendered the FhuC derivatives unable to displace wild-type FhuC. It is concluded that the physical interaction between FhuC and FhuB implies a coordinate activity of both proteins in the transport of iron(III) hydroxamates through the cytoplasmic membrane.

ATP-Binding Cassette Transporters↗
PubMed1992

[Inguinal hernia as a sequela of disordered bladder emptying?].

We examined 56 patients with hernias and 49 patients with other diseases prior to operation. They were all above 50 years of age. The urological screening examination included the patients history of the frequency of urination during night and day time, dysuria, the common risk factors (smoking, coughing, obstipation), obesity, a sonographic measurement of the prostate diameters, a sonographic evaluation of residual urine and the determination of the urinary flow rate. None of the above parameters showed a significant difference between the two groups. Surprisingly more than 60% of all men showed a pathological voiding function (either residual urine and/or a pathological flow rate). Our conclusions are: 1. Patients with inguinal hernias do not show a greater incidence of pathological bladder function than patients of the control group. The benign prostatic hypertrophy as a risk factor for the development of inguinal hernias is most questionable. 2. Because the results showed no significant difference between the two groups, a determination of residual urine prior to operation is not necessary. 3. More than 60% of the men above 50 years showed a pathological voiding function. We recommend a urological screening test for all men above 50 years of age during hospitalisation.

Aged↗
PubMed1992

[Hemorrhage-induced rupture of the pancreatic pseudocyst].

Hemorrhage from pseudocyst may be the most serious complication of chronic pancreatitis: the mortality from such hemorrhage approaches 80%. The bleeding arises from a major artery--the artery is eroded by the basic process of autodigestion, and the pseudocyst is converted into a pseudoaneurysm. The wall of the pseudoaneurysm is subjected to arterial pressure and may perforate into the peritoneal cavity, an adjacent segment of the gastrointestinal tract, or the pancreatic ductal system. Clinical signs and indications of complicated pseudocyst are sudden abdominal pain, hypotension, sudden increase in abdominal tenderness, decrease of hematocrit and sudden disappearance of the mass. Sonography, CT and angiography accurately define the bleeding lesion and greatly aid in planning operative strategy. Surgery, angiographic embolisation, or a combination of both may be employed. Transcystic arterial ligation and internal drainage of the pseudocyst or distal pancreatectomy are the operative procedures of choice and give the best results.

Diagnosis, Differential↗
PubMed1991

[HIV transmission in hospitals and office practice. Protection of patients and medical personnel].

Research has brought full knowledge of the identity of the human immunodeficiency virus (HIV) and its infective pathways. There are not enough diagnostic tools, however, to detect all HIV carriers in the first weeks and months after infection. This fact emphasizes that all patients should be assumed to be infectious for HIV and other bloodborne pathogens. A slight but certainly existent risk for all health-care workers is a reality. Information and recommendations concerning the protection of surgical personnel against acquisition of HIV while performing their duties, and protection of HIV carriers, were published in 1988 by the Union of Swiss Surgical Societies, Practicability and compliance with these infection-control precautions were checked in 1990 after two years' operation with the aid of a questionnaire. 89 valid answers from 110 Swiss hospitals (yielding a response rate of 81%), together with overall experience, allow us to evaluate the recommendations of 1988. We conclude that the risk of HIV infection after occupational exposure to blood and other body fluids, and the potential threat to the HIV carrier, can be minimized to a very high degree by acceptance of the recommended infection-control precautions. This is especially true in surgical units, emergencies and first aid.

Carrier State↗
PubMed1991

Suitability of different silver enhancement methods applied to 1 nm colloidal gold particles: an immunoelectron microscopic study.

In order to exploit the recently introduced 1 nm gold colloids in routine electron microscopic labeling experiments, an efficient enhancement step for a better visualization of this small marker is a prerequisite. Efficiency and reproducibility of enhancement as well as growth homogeneity of gold particles were evaluated for three different silver intensifying solutions: silver lactate/hydroquinone/gum arabic (Danscher, 1981), Ilford L4/Metol (Bienz et al., 1986), and the commercially available IntenSE M silver enhancement kit (Janssen Pharmaceutica). The best results were obtained by using the silver lactate/hydroquinone/gum arabic mixture. The quality of enhancement of the IntenSE M kit was considerably increased by the addition of the protective colloid gum arabic.

Bacterial Outer Membrane Proteins↗
PubMed1991

High precision immunoscanning electron microscopy using Fab fragments coupled to ultra-small colloidal gold.

Ultra-small colloidal gold (less than 1 nm), bound to Fab fragments provides the shortest practical specific marker system to date and can be used in concert with field emission scanning electron microscopes to precisely locate antigenic sites. An "in-lens" FE-SEM equipped with a highly sensitive single crystal YAG-detector for backscattered electrons, as well as the use of advanced specimen preparation techniques based on cryofixation, are among the indispensible prerequisites. A T-even type Escherichia coli bacteriophage, Tu II*-46, was chosen to study properties of the immunogold labeling system. Distinct regions on the tail fibers of this phage were labeled with Fab fragments derived from antibodies against the related phage Tu II*-6. The tail fibers are composed of pairs of homologous proteins, thus offering two identical antigenic sites at the same locus on the tail fibers. Fab fragments can be visualized in the SEM at high accelerating voltage (30 kV) without any additional marker. This permits comparison of the labeling characteristics of unmarked and colloidal gold-marked Fab fragments. Unmarked Fab fragments often bind by pairs (two singlet Fab fragments bound opposed to each other along the axis of the tail fiber). The labeling efficiency of unmarked Fab fragments was greater than that of ultra-small gold-labeled Fab fragments. Binding by pairs was not seen after labeling with ultra-small gold-Fab fragments. The conjugates used in this study exhibited one colloidal gold per Fab fragment.

Animals↗