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H Müller

Publications and source records attributed to H Müller.

At least 235 records · Page 13Linked to original sources
PubMed1996

Molecular analysis of the amy gene locus of Thermoanaerobacterium thermosulfurigenes EM1 encoding starch-degrading enzymes and a binding protein-dependent maltose transport system.

A gene of Thermoanaerobacterium thermosulfurigenes EM1 encoding a protein with similarity to the maltose-binding protein of Escherichia coli was cloned and sequenced. It was located in the amy gene region of the chromosome downstream of the pullulanase-encoding amyB gene and upstream of amyDC, encoding membrane components of an ABC transport system, and the alpha-amylase gene amyA. The gene was designated amyE. Analysis of mRNA by Northern (RNA) blotting revealed that expression of the amy gene region is repressed during growth on glucose. Maximum levels of mRNA were detected with maltose as a substrate. An operon which was transcribed in the order amyBEDC was identified. However, an additional transcription start point was found in front of amyE. The amyA gene represented a monocistronic operon. Putative -35 and -10 promoter sites were deduced from the three transcription start sites of the amy gene region, and possible regulatory regions mediating induction by maltose and catabolite repression by glucose were identified by sequence analysis and comparison. The biochemical characterization of maltose uptake in T. thermosulfurigenes EM1 revealed two transport systems with Km values of 7 microM (high affinity) and 400 microM (low affinity). We conclude that the high-affinity system, which is specific for maltose and maltotriose, is a binding-protein-dependent transporter encoded by amyEDC. The gene for the putative ATP-binding protein has not yet been identified, and in contrast to similar systems in other bacteria, it is not located in the immediate vicinity of the chromosome.

ATP-Binding Cassette Transporters↗
PubMed1996

Correlation between the development of extracolonic manifestations in FAP patients and mutations beyond codon 1403 in the APC gene.

The APC gene was investigated in 31 unrelated polyposis coli families by SSCP analysis and the protein truncation test. Twenty-three germline mutations were identified which gave rise to a variety of different phenotypes. Some of these mutations have already been described; however we report six previously unpublished mutations. Typical disease symptoms were observed in families who harboured mutations between exon 4 (codon 169) and codon 1393 of exon 15. Mutations beyond codon 1403 were associated with more varied phenotype with respect to the development of extracolonic symptoms. In this report we provide support for the notion that there appears to be a correlation between the location of an APC mutation (beyond codon 1403) and extracolonic manifestations of familial adenomatous polyposis.

Adenomatous Polyposis Coli↗
PubMed1996

BRCA1 mutations in a selected series of breast/ovarian cancer patients.

Germline mutations in the BRCA1 gene have been associated with familial breast/ ovarian cancer in large families showing high penetrance of the disease. Little is known, however, about the contribution of BRCA1 mutations to breast/ovarian cancer in small families with few affected members or in isolated early onset cases. Therefore we examined the BRCA1 gene in 63 breast/ovarian cancer patients who either came from small families with as few as one affected first degree relative, or in patients who had no family history but had developed breast cancer under 40 years of age. Using the protein truncation test, we were able to identify three unique BRCA1 germline mutations (4.8%). Two of the probands had only one affected first degree and several second degree relatives and the third had three affected first degree relatives including two sisters who, when tested, were also found to carry the mutation. There was no family history of ovarian cancer in any of the three families.

Adult↗
PubMed1996

Gender and AD.

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Aged↗
PubMed1996

Effects of perorally applied endotoxin on colonic mucins of germfree rats.

BACKGROUND: The intestinal epithelium, with the potential to restrict luminal noxae from the host, secretes a mucous layer with various protective functions. Microbial colonization of germfree (GF) rats stimulates this mucin-secreting tissue. The present study determined the effect of bacterial lipopolysaccharides (LPS) on this process. METHODS: One, 3, and 5 days after peroral application of 35 micrograms LPS/100 g body weight (from Escherichia coli O55:B5), LPS concentrations were monitored in ingesta, intestinal tissue, and liver. Mucin high molecular weight glycoproteins (HMG), released in response to LPS, were isolated and separated into mucins, i) attached to the colonic epithelium (EM) and ii) mixed to the luminal content (LM), respectively. Subsequently, the binding capacity of both mucin fractions for various lectins and for type-1 pili expressing E. coli was determined. RESULTS: Ingesta and tissue had maximal LPS concentrations on days 3 (jejunum) and 5 (colon). Maximal EM secretion was found on day 3, release of LM further increased to day 5. Both mucin fractions had altered glycosylation patterns: augmentation of beta-galactose, alpha-N-acetyl galactosamine, and mannose coincided with a decrease in alpha-fucose. Compared with the controls, attachment of E. coli to EM increased slightly on day 1 only; the binding capacity of LM increased continuously up to day 5. CONCLUSION: Results suggest that mucins, released in response to LPS, in addition to the epithelial protection, support the gut microbial clearance system.

Administration, Oral↗
PubMed1996

Action of vasopressin in superfused human granulosa cells in vitro.

Arginine-vasopressin as well as luteinizing hormone (LH)/follicle-stimulating hormone (FSH) stimulate progesterone release in superfused human granulosa cells. Extracellular administration of inositol triphosphate (10(-6) mol/l) or calcium ions (10(-4) mol/l) mimics the action of both arginine-vasopressin and LH/FSH and evokes progesterone secretion in superfused granulosa cells.

Arginine Vasopressin↗
PubMed1996

[75-Se-labeled bile acid analog absorption in various gastrointestinal diseases using a whole body counter].

AIM: It is possible to detect disturbances of bile acid absorption using a whole body counter after administration of Se-75 labelled bile acid analogues. We scrutinized the benefit of a modification of the test method. METHODS: We investigated 77 patients with different forms of a gastrointestinal disease. After application of Se 75 homotaurocholic acid we measured patient-activity up to 7 days later including whole-body profile scans in the first 6 h. RESULTS: The fractional retention after 7 days was between 20 and 67%. In cases of impaired absorption it was below 12%. Patients with liver diseases and after cholecystectomy (without bile acid resorption disturbance) showed normal values. Patients with Crohn's disease of the ileum or with intestinal ileac by-pass or with colestyramine treatment or with disturbance of vitamin B12-absorption or with cystic fibrosis showed a disturbance of bile acid absorption. The normal whole-body half-life was more than 2.8 days. The 24 and 72 h values were 62 and 31% in cases with normal absorption. Smaller values are signs of bile acid malabsorption. Impulse rates measured with the whole body counter are of an order of magnitude that allows to reduce the usually administered dose of 37 kBq to 9.25 kBq. CONCLUSION: This is an efficient method to detect disturbances of bile acid absorption. The usually administered activity of 37 kBq can be reduced to 9.25 kBq.

Adult↗
PubMed1996

Troponin T as a marker for posttransplantation adaptational problems of the donor heart.

BACKGROUND: Troponin T is used as a marker for myocardial cell damage (e.g., in aiding diagnosis and follow-up of myocardial infarction). Elevated troponin T levels are also observed after heart transplantation, although until now no explanation could be found for this phenomenon. METHODS AND RESULTS: Serum samples of 15 patients who underwent orthotopic heart transplantation were tested for troponin T with a one-step enzyme immunoassay. The highest concentrations of troponin T were seen between day 3 and 14 after transplantation (3.05 +/- 1.30 micrograms/L) and remained elevated up to 3 months. A correlation (r = 0.61, p < 0.02) was found between pretransplantation systolic pulmonary artery pressure and the cumulative troponin T release after transplantation. No association was found with rejection, and no correlation was found with ischemic time of the donor heart. CONDITIONS: These findings support the hypothesis that the acute exposure of the donor heart to the preexisting elevated right ventricular afterload in the recipient represents a strong mechanical stress for the transplanted heart. Measurement of troponin T may therefore be helpful in the posttransplantation monitoring and management of ventricular function after orthotopic heart transplantation.

Adaptation, Physiological↗
PubMed1996

Vasopressin V2 receptor mutants that cause X-linked nephrogenic diabetes insipidus: analysis of expression, processing, and function.

We investigated the biochemical and functional properties of five vasopressin V2 receptor mutants (L44F, L44P, W164S, S167L, and S167T) that were recently described in families with a history of X-linked nephrogenic diabetes insipidus. COS.M6 cells transfected with cDNA encoding these mutants acquired < 4% specific [3H]arginine vasopressin (AVP) binding sites on the cell surface in comparison with cells transfected with cDNA coding for the wild-type receptor. Membrane preparations from COS.M6 cells or human embryonic kidney 293 cells expressing these mutants did not respond with an increase in adenylyl cyclase activity in response to AVP, which is in contrast to membranes from cells expressing the wild-type. By analyzing fusion proteins of the V2 receptor and Escherichia coli alkaline phosphatase attached to the carboxyl terminus of the receptor moiety, we found that the mutants L44P, W164S, S167L, and S167T lacked complex glycosylation and were expressed at low levels. The data suggest that the mutants L44P, W164S, S167T, and S167L are misfolded and therefore retained within the endoplasmic reticulum and degraded. In contrast, the fusion proteins carrying the mutant L44F and the in vitro mutant S167A were expressed in their mature form at wild-type levels; however, only the mutant S167A was functionally active. Site-directed mutagenesis of S167 revealed that elimination of the endogenous hydroxyl group (S167A) yielded a protein with properties identical to those of the wild-type receptor, whereas both the introduction of a methyl group (S167T) and the replacement of the hydroxyl group by an isopropyl group (S167L) profoundly disturbed receptor processing. The data show that minute changes at codon 167 nearly abolish expression of a mature protein, thus defining structural requirements of this codon.

Alkaline Phosphatase↗
PubMed1996

Response of germfree rat colonic mucous cells to peroral endotoxin application.

During microbial colonization, mucin-releasing goblet cells of germ-free (GF) rats proliferate and upregulate their mucin synthesis, thus improving the intestinal mucus barrier. The present study determined the significance of bacterial membrane constituents for this development. A single dose of lipopolysaccharide (LPS) (35 micrograms/100 g body weight) and lipid A (3.5 micrograms/100 g body weight, respectively), was perorally administered to GF AS/Ztm rats. One, 3 and 5 days later, sections of the proximal and distal colon served for characterization of mucin-secreting goblet cells, released mucins were isolated in parallel. Maximal goblet cell diameters were evidenced at day 3. LPS generated a maximal goblet cell hyperplasia one day after challenge, lipid A stimulated the goblet cell proliferation continuously up to day 5. Three days after challenge with one of the stimuli, either, intracellular mucins had shifted significantly to neutral constituents. In addition, mucins, adherent to the colon mucosa and submerged to the luminal content, respectively, then were augmented. At day 5, adherent mucins were similar to the controls, while luminal, soluble constituents had further increased. Histometrical and biochemical methods evidenced a transient, inflammatory response of mucin-secreting cells, followed by an upregulated release of immature mucins.

Administration, Oral↗
PubMed1996

[Methods, value and limits of prenatal hearing diagnosis].

An intrauterine sound test was developed for monitoring prenatal hearing disorders and evaluated concerning its efficacy and practical feasibility. The procedure is based on the fetesto capacity react upon exogenous sound stimulation. An acoustic stimulation was achieved by a noise generator placed directly on the maternal abdomen in the proximity of the fetal ear. Successful stimulation was monitored by sonographic means expressed as fetal child movements in 447 pregnant women at the end of the 26th to the 37th week of gestation. The most favourable time for an intrauterine hearing test is between the 30th and 32nd week of gestation. The quantity of amniotic liquor, placental location and pathological pregnancies influences the test results. Efficiency and limits of prenatal hearing diagnostics are discussed.

Acoustic Stimulation↗
PubMed1995

Early phase in the infection of cultured cells with papillomavirus virions.

The fate of full bovine papillomavirus (BPV) virions and virus-like particles after binding to C127 or CV-1 cells was studied by electron microscopy and indirect immunofluorescence. After incubation at 4 degrees for 1 hr, BPV virions were found to be bound to the plasma membrane, and most viruses were absorbed by the cells after 30 min incubation at 37 degrees. Ninety minutes after the virions had been bound to the plasma membrane, the uptake of the virions was completed and most of the antigen was found to be localized in the nucleus. The viruses were transported in phagosomes and the uptake and transportation could be inhibited by cytochalasin B and taxol, suggesting the possible involvement of microfilaments and microtubules in the virus particle uptake and transportation. The capsid proteins could be detected for about 14 hr, until degradation and deposit of the viral antigen in the Golgi complexes. Although binding to the plasma membrane and uptake of virions into large cytoplasmic vesicles could be monitored by electron microscopy, no complete virions were observed in the nucleus of infected cells despite a very strong nuclear fluorescent staining for both L1 and L2 proteins. This may indicate that disintegration of the virions occurs in the cytoplasm and the L1/L2 proteins migrate to the nucleus via their nuclear localization signals.

Animals↗
PubMed1995

Effect of initial treatment with antidepressants as a predictor of outcome after 8 weeks.

Most findings of antidepressant treatment prediction have not been replicated, and this applies to biological predictors as well as sociodemographic and early course predictors. One exception might be early psychopathological improvement. To reevaluate this question, we examined the results of two large-scale controlled clinical trials comparing the selective and reversible inhibitor of monoamine oxidase type A (MAO-A) brofaromine with the standard tricyclic compound imipramine. One trial was carried out in a normal-aged patient group; the other, in elderly patients. Above all, we were interested in determining whether early treatment course would prove predictive of later outcome. The main finding was that the initial antidepressant effect (measured after 1 and 2 weeks) predicted longer term outcome. Although this association was not as strong in the elderly patient group, its predictive value did possess a certain clinical relevance.

Adult↗