PubMed Health⌕ Search

Biomedical subjects

K Fuchs

Publications and source records attributed to K Fuchs.

At least 91 records · Page 5Linked to original sources
PubMed1991

N-deglycosylation and immunological identification indicates the existence of beta-subunit isoforms of the rat GABAA receptor.

beta 2- and beta 3-subunits of GABAA receptors purified from the brains of 5-10-day-old rats were investigated in the intact or completely N-deglycosylated state using the beta-subunit-specific monoclonal antibody bd-17 and polyclonal antibodies directed against synthetic amino acid sequences specific for the GABAA receptor beta 2- or beta 3-subunits. The present results seem to indicate the existence of two different isoforms of the beta 3-subunit and several different isoforms of the beta 2-subunit of the GABAA receptor which probably are produced by alternative splicing.

Amidohydrolases↗
PubMed1991

Characterization of nucleotide sequences from European hepatitis C virus isolates.

We characterized the 5' end and parts of the structural genes of European isolates of hepatitis C virus (HCV) and compared them with recently published RNA sequences of American and Japanese HCV isolates. The cDNA, obtained by reverse transcription of viral RNA extracted from different sera, was amplified by nested PCR, cloned and sequenced. Within 239 nucleotides (nt) of the 5' end, we found only three single-nt exchanges compared to two sequences of Japanese origin and one exchange to the prototype HCV sequence (ptHCV) (homology greater than 99%). The sequence of the core region (534 nt) in two European isolates showed a homology of about 97-98% on the nt level, as compared to ptHCV and one Japanese isolate, and 90% to other Japanese isolates. The amino acid (aa) homology was between 98-99% among all published sequences. A greater discrepancy was found in the European isolates within the 434 nt sequenced from the N-terminus of the putative envelope region, where the nt homology to ptHCV and one Japanese isolate was 90-93% (aa homology 93-95%), and to other Japanese isolates was 72-73% (aa homology 77-78%), indicating that the European isolates may be more closely related to the ptHCV and one Japanese isolate than to the other Japanese isolates. Amplified genes encoding structural proteins (core, envelope) were expressed in Escherichia coli. Sera from chronically infected patients reacted strongly with the recombinant core protein, but no specific immunoreactivity occurred with the putative envelope protein.

Amino Acid Sequence↗
PubMed1991

Flow cytometric characterization and sorting of cultured Brassica napus microspores.

A flow cytometric procedure was used to characterize and sort embryogenic Brassica napus microspore cultures. Embryogenic microspores continued to increase in size throughout the culture period and fluoresced when stained with fluoresecein diacetate (FDA). However, most of the cells in culture (greater than 95%) lost their viability over the culture period and the correlation between the percentage viable cells in a culture and the productivity of the culture was not significant until day 3. By sorting large fluorescent cells on day 1 and day 3 of the culture period populations of cells that were 7-18-fold more embryogenic than sorted mixed cells were obtained. The flow cytometric procedure would be useful for rapidly assessing the effects of a large variety of culture and media conditions on embryogenesis is rapeseed microspore cultures. Furthermore, the populations of potentially embryogenic microspores isolated by flow cytometry might be useful for studies of the early cellular and molecular changes that occur during androgenesis in rapeseed.

Brassica↗
PubMed1991

Degradation of 2-methylaniline and chlorinated isomers of 2-methylaniline by Rhodococcus rhodochrous strain CTM.

Rhodococcus rhodochrous strain CTM co-metabolized 2-methylaniline and some of its chlorinated isomers in the presence of ethanol as additional carbon source. Degradation of 2-methylaniline proceeded via 3-methylcatechol, which was metabolized mainly by meta-cleavage. In the case of 3-chloro-2-methylaniline, however, only a small proportion (about 10%) was subjected to meta-cleavage; the chlorinated meta-cleavage product was accumulated in the culture fluid as a dead-end metabolite. In contrast, 4-chloro-2-methylaniline was degraded via ortho-cleavage exclusively. Enzyme assays showed the presence of catechol 1,2-dioxygenase and catechol 2,3-dioxygenase as inducible enzymes in strain CTM. Extended cultivation of strain CTM with 2-methylaniline and 3-chloro-2-methylaniline yielded mutants, including R. rhodochrous strain CTM2, that had lost catechol 2,3-dioxygenase activity; these mutants degraded the aromatic amines exclusively via the ortho-cleavage pathway. DNA hybridization experiments using a gene probe revealed the loss of the catechol 2,3-dioxygenase gene from strain CTM2.

Aniline Compounds↗
PubMed1991

Degradation of 2-methylaniline in Rhodococcus rhodochrous: cloning and expression of two clustered catechol 2,3-dioxygenase genes from strain CTM.

Rhodococcus rhodochrous strain CTM degrades 2-methylaniline mainly via the meta-cleavage pathway. Conversion of the metabolite 3-methylcatechol was catalysed by an Mr 156,000 catechol 2,3-dioxygenase (C23OI) comprising four identical subunits of Mr 39,000. The corresponding gene was detected by using an oligonucleotide as a gene probe. This oligonucleotide was synthesized on the basis of a partial amino acid sequence obtained from the purified enzyme from R. rhodochrous. The structural gene of C23OI was located on a 3.5 kb BglII restriction fragment of plasmid pTC1. On the same restriction fragment the gene for a second catechol 2,3-dioxygenase, designated C23OII, was found. This gene coded for the synthesis of the Mr 40,000 polypeptide of the Mr 158,000 tetrameric C23OII. More precise mapping of the structural genes showed that the C23OI gene was located on a 1.2 kb BglII-SmaI fragment and the C23OII gene on the adjacent 1.15 kb SmaI fragment. Comprehensive substrate range analysis showed that C23OII accepted all the substrates that C23OI did, but additionally cleaved 2,3-dihydroxybiphenyl and catechols derived from phenylcarboxylic acids. C23OI exhibited highest activity towards methylcatechols, whereas C23OII cleaved unsubstituted catechol preferentially.

Aniline Compounds↗
PubMed1990

Identification of alpha 2- and alpha 3-subunits of the GABAA-benzodiazepine receptor complex purified from the brains of young rats.

Polyclonal antibodies were raised to synthetic amino acid sequences of the bovine GABAA receptor alpha 2- and alpha 3-subunits and purified by affinity chromatography on a column coupled with the respective peptide. Anti-peptide alpha 2(416-424) and anti-peptide alpha 3(459-467) antibodies immunoprecipitated GABAA receptors and recognized a protein of 53 kDa (P53) and 59 kDa (P59), respectively, in Western blots of GABAA receptors purified from the brains of 5-10 day old rats. P53 as well as P59 are specifically photolabeled by [3H]flunitrazepam and are recognized by the alpha-subunit specific monoclonal antibody bd 28.

Animals↗
PubMed1990

Different outcomes of chronic hepatitis delta virus infection in woodchucks.

Hepatitis delta virus (HDV) superinfection of woodchuck chronic carriers of woodchuck hepatitis virus (WHV) results in acute and chronic disease. The different courses of disease mimicked the outcome of human HDV superinfection, making woodchucks valuable models for clinical studies of HDV. Ten of 11 woodchuck chronic carriers of WHV superinfected with HDV developed acute HDV infection with markers of viral replication in the serum and liver. One animal (DW128) had no serological markers of acute HDV infection. Nine of 11 (82%) superinfected animals developed chronic HDV infection. An unusual course of chronic HDV infection occurred in one woodchuck (DW128): no serum markers of acute or chronic HDV infection appeared but HDV RNA was detected in the liver, indicating that chronic HDV infection can occur without serological markers.

Acute Disease↗
PubMed1989

Evidence for the existence of several different alpha- and beta-subunits of the GABA/benzodiazepine receptor complex from rat brain.

gamma-Aminobutyric acid (GABA)/benzodiazepine receptors purified from the brains of young and adult rats were photolabeled by [3H]flunitrazepam or [3H]muscimol. Gel electrophoresis revealed 3 different proteins with apparent molecular weight (Mr) 51,000, 53,000 and 59,000 which were specifically and irreversibly labeled by [3H]flunitrazepam and recognized by the alpha-subunit specific antibody bd-28. Similarly, 3 different proteins with Mrs 51,000, 53,000 and 56,000 were irreversibly labeled by [3H]muscimol and recognized by the beta-subunit-specific antibody bd-17. Comparison of the photolabeling and immunological staining pattern from young and adult rats seems to indicate that proteins labeled by [3H]flunitrazepam and bd-28 are different from those labeled by [3H]muscimol and bd-17.

Affinity Labels↗
PubMed1989

Characterization of woodchuck hepatitis virus DNA and RNA in the hepatocellular carcinomas of woodchucks.

Integration and transcription of woodchuck hepatitis virus DNA were studied by Southern and Northern blot analysis in 26 hepatocellular carcinomas and in adjacent nontumor tissue of woodchucks (Marmota monax). All liver tissue chronically infected with woodchuck hepatitis virus contained various amounts of episomal and replicative forms of woodchuck hepatitis virus DNA: episomal and replicative forms of woodchuck hepatitis virus DNA without integration were found in six tumors, episomal and integrated woodchuck hepatitis virus DNA was observed in 18 tumors and exclusively integrated woodchuck hepatitis virus DNA was found in two tumors. In most tumors and in all of the liver tissues chronically infected with woodchuck hepatitis virus, two major woodchuck hepatitis virus RNA species (3.7 and 2.1 kilobases) were detected. In tumors of two other animals (HW76 and HW89) with integrated woodchuck hepatitis virus DNA, only single major transcripts of 3.5 and 2.5 kilobases, respectively, were detected. Hybridization with subcloned woodchuck hepatitis virus DNA probes showed that both aberrant transcripts lacked the C gene and a part of the pre-S1 gene; characterization of corresponding integrated woodchuck hepatitis virus DNA sequences revealed that the C gene was deleted in one tumor, although not in the other. In agreement with the nucleic acid data, we found expression of core protein by Western blotting only in chronically infected liver tissue of these animals, but not in the corresponding tumors. Deletion of the C gene in mRNA may be due to deletion of this gene in the integrated sequences or due to transcriptional regulation.

Animals↗
PubMed1989

Protection of woodchucks from infection with woodchuck hepatitis virus by immunization with recombinant core protein.

Woodchucks were immunized with recombinant woodchuck hepatitis virus (WHV) core antigen (WHcAg) to investigate whether such immunization protects against WHV infection. The C gene was cloned into a pUC12 vector and expressed in Escherichia coli. Core particles purified by sucrose and CsCl gradient centrifugation had a buoyant density of 1.37 g/ml which corresponded to the density of WHcAg particles present in chronically infected liver. Two animals immunized with the recombinant antigen developed high antibody titres and were protected against infection after challenge with WHV. The surface antigen (WHsAg) and WHV DNA were not detected in the sera of immunized animals after challenge and these animals did not develop anti-WHs. Three control animals developed a typical WHV infection. The protection from WHV infection may depend not on the presence of antibodies against the core protein but on a cellular immune response to WHcAg.

Animals↗
PubMed1989

envM genes of Salmonella typhimurium and Escherichia coli.

Conjugation and bacteriophage P1 transduction experiments in Escherichia coli showed that resistance to the antibacterial compound diazaborine is caused by an allelic form of the envM gene. The envM gene from Salmonella typhimurium was cloned and sequenced. It codes for a 27,765-dalton protein. The plasmids carrying this DNA complemented a conditionally lethal envM mutant of E. coli. Recombinant plasmids containing gene envM from a diazaborine-resistant S. typhimurium strain conferred the drug resistance phenotype to susceptible E. coli cells. A guanine-to-adenine exchange in the envM gene changing a Gly codon to a Ser codon was shown to be responsible for the resistance character. Upstream of envM a small gene coding for a 10,445-dalton protein was identified. Incubating a temperature-sensitive E. coli envM mutant at the nonpermissive temperature caused effects on the cells similar to those caused by treatment with diazaborine, i.e., inhibition of fatty acid, phospholipid, and lipopolysaccharide biosynthesis, induction of a 28,000-dalton inner membrane protein, and change in the ratio of the porins OmpC and OmpF.

Alleles↗
PubMed1988

Various proteins from rat brain, specifically and irreversibly labeled by [3H]flunitrazepam, are distinct alpha-subunits of the GABA-benzodiazepine receptor complex.

gamma-Aminobutyric acid (GABA)-benzodiazepine receptors were purified from the brains of 5 to 10-day-old rats and photolabeled by [3H]flunitrazepam. After sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), 3 different proteins with apparent molecular weight 51,000, 53,000 and 59,000 Da specifically and irreversibly labeled by [3H]flunitrazepam were revealed by autoradiography. The same 3 proteins were recognized by the alpha-subunit-specific monoclonal antibody bd-28. In contrast, a different protein with apparent molecular weight 56,000 Da was recognized by the beta-subunit-specific antibody bd-17. These results indicate that the various proteins specifically labeled by [3H]flunitrazepam are different alpha-subunits and distinct and different from the beta-subunit of the GABA-benzodiazepine receptor complex.

Animals↗
PubMed1988

Modification of the apparent molecular weight of different benzodiazepine binding proteins from rat brain membranes by various endoglycosidases.

Membranes from rat cerebellum or hippocampus were photolabeled by [3H]flunitrazepam and incubated with various endoglycosidases. The largest reduction in apparent molecular weight of photolabeled proteins P51 (mol. wt. 51,000) and P55 (mol. wt. 55,000) was obtained using endoglycosidase F or glycopeptidase F. However, even after extensive treatment with these enzymes the deglycosylated products of proteins P51 (apparent mol. wt. 44,000) and P55 (two peptides with apparent mol. wt. 48,000 and 51,000) still differed in their apparent molecular weight. This might indicate that structural features other than N-linked carbohydrates are responsible for the difference in apparent molecular weight of these proteins.

Acetylglucosaminidase↗
PubMed1988

The influence of maternal hypnosis on fetal movements in anxious pregnant women.

The influence of maternal hypnotherapy on fetal body movements in anxious parturients was studied in 25 patients at 35-37 weeks of gestation. There were two groups of patients. Group A consisted of 16 parturients who performed self-hypnosis. Group B consisted of 9 parturients in whom hypnosis was induced by a physician. When compared to a control period of 30 min there was a significant increase in the duration of fetal body movements recorded by ultrasound during 30 min of maternal hypnosis, p less than 0.005 for group A and p less than 0.01 for group B. It is suggested that in anxious parturients fetuses move into a more active state when maternal relaxation is achieved by hypnotherapy.

Anxiety↗
PubMed1985

The "grand multipara"--is it a problem? A review of 5785 cases.

The Grand Multipara (GM) has almost disappeared in the Western countries due to the advancement of family planning. Having a heterogeneous population, the problem of Grand Multiparity still exists in our country. This study is based on 5785 cases of GM which were treated in our Obstetrical Department during a period of 16 years (1960-1975). We have compared this group to the general obstetrical population in terms of pregnancy and delivery complications. Face and breech presentations as well as transverse lie were twice, brow presentations were three times as frequent in the GM group. Postpartum hemorrhage (P.P.H.) was four times and premature separation of the placenta twice as frequent. Rupture of the uterus was about 20 times more frequent. Forceps delivery and Cesarean section rate were twice, while the vacuum extraction 5-fold more frequent. Though there was no material mortality and perinatal mortality was not higher than in the general population. Even though the percentage of GM in our population has been decreased in the last 10 years, our results suggest that Grand Multiparity is still a high risk obstetrical problem.

Female↗