Search PubMed⌕ Search

Biomedical subjects

M Müller

Publications and source records attributed to M Müller.

At least 919 records · Page 51Linked to original sources
PubMed1994

Comparison of peptide enzyme-linked immunosorbent assay and radioimmunoprecipitation assay with in vitro-translated proteins for detection of serum antibodies to human papillomavirus type 16 E6 and E7 proteins.

Antibodies to human papilloma virus (HPV) type 16 (HPV-16) E6 and E7 proteins in serum are markers for HPV-associated invasive cervical carcinoma. We compared two assays, a radioimmunoprecipitation assay with in vitro-translated HPV-16 E6 and E7 proteins and an enzyme-linked immunosorbent assay (ELISA) with E6 and E7 synthetic peptides, for their abilities to discriminate serologically between patients with invasive cervical cancer and controls. Among the patients, antibody prevalences were higher by the E6 radioimmunoprecipitation assay (55.7%) than by the E6 peptide ELISA (15.5%), but among the controls, they were lower by the radioimmunoprecipitation assay (1.7%) than by the E6 peptide ELISA (5%). For E7, antibody prevalences among the patients were comparable by the radioimmunoprecipitation assay (43%) and the peptide ELISA (41%), but among the controls they were higher by the E7 peptide ELISA (17.4%) than by the radioimmunoprecipitation assay (4.1%). There was good agreement between the E7 radioimmunoprecipitation assay and the E7 peptide ELISA among patients but not among controls. In tests with representative sera, heat denaturation of the translated proteins resulted in a complete loss of reactivity to the E6 protein and a marked decrease in reactivity to the E7 protein. Our study showed that the radioimmunoprecipitation assay discriminates better than the peptide ELISA between patients with invasive cervical cancer and controls and that this is related to the ability of the radioimmunoprecipitation assay to detect conformational epitopes.

Antibodies, Viral↗
PubMed1994

Tissue factor controls the balance of angiogenic and antiangiogenic properties of tumor cells in mice.

Meth-A sarcoma cells were stable transfected to overexpress (sense construct) or underexpress (antisense construct) tissue factor. In vitro, there was no difference in plating efficiency or growth between these cell lines. In vivo, tumor cells transfected to overexpress tissue factor grew more rapidly, and established larger and more vascularized tumors than control transfectants. Antisense transfectants grew the slowest and were the least vascularized. Anticoagulation of mice with warfarin did not alter the difference between these tumor lines. Tumor cells over-expressing tissue factor released more (compared with control transfectants) mitogenic activity for endothelial cells in parallel with enhanced transcription of vascular permeability factor/vascular endothelial cell growth factor (VEGF/VPF), and diminished transcription of thrombospondin (TSP2), a molecule with anti-angiogenic properties. Antisense tissue factor transfectants, while releasing the lowest amount of mitogenic activity, had increased thrombospondin and decreased VEGF/VPF transcription compared with control transfectants or wild-type cells. Experiments with these sense, antisense, truncated sense, or vector tumor lines gave comparable results in complete medium, serum free medium or in the presence of hirudin, indicating that the activation of the coagulation mechanism was not likely to be responsible for changes in tumor cell properties. These results suggest that tissue factor regulates angiogenic properties of tumor cells by altering the production of growth regulatory molecules of endothelium by a mechanism distinct from tissue factor activation of the coagulation mechanism.

Animals↗
PubMed1994

Analysis of oxygen radical toxicity in pancreatic islets at the single cell level.

Despite extensive studies on streptozotocin, alloxan and nitric oxide toxicity in pancreatic islets the mechanism of oxygen radical induced islet cell death has not been determined. The present study shows at the level of single cells that following exposure to oxygen radicals generated from xanthine oxidase DNA strand breaks occur in cell nuclei within 5-60 min and precede cell death by several hours. Similar kinetics were seen when treating islet cells with the alkylating agent streptozotocin. Immunofluorescence studies demonstrated the endogenous formation of ADP-ribose polymers in nearly all islet cell nuclei within minutes of treatment with xanthine oxidase, indicating activation of the enzyme poly(ADP-ribose) polymerase (PARP). Concomitantly, cellular NAD+ depletion was noted. Nicotinamide largely prevented NAD+ depletion and in parallel resulted in islet cell survival. These findings identify islet cell nuclear DNA as a primary target of oxygen radical toxicity and suggest related pathways of oxygen radical, nitric oxide and streptozotocin toxicity.

Animals↗
PubMed1994

Radical surgery (R2 resection) for gastric cancer. A multivariate analysis.

BACKGROUND: Extended lymphadenectomy remains controversial in the Western world. Its evaluation and the identification of high-risk patients after surgery are important tasks. METHODS: A retrospective prognostic study of 318 patients treated for potential cure of gastric cancer was performed. All patients underwent extended lymphadenectomy. Clinical histopathologic and surgical factors were examined for their influence on survival by univariate and multivariate analysis. RESULTS: Postoperative mortality was 4.4% (14 of 318), and the 5-year adjusted survival rate was 57.8%. Multivariate analysis using the Cox model identified seven factors as having independent influence on survival. Detrimental factors were male gender, age over 65 years, high pN category, increasing number of lymph nodes invaded by metastases, total gastric resection, splenectomy, and increasing number of perioperatively required blood units. CONCLUSION: Extended lymphadenectomy was possible without sacrificing low postoperative mortality rates. The importance of certain prognostic factors, in particular lymph node status, could be confirmed.

Aged↗
PubMed1994

The proteins encoded by two tapetum-specific transcripts, Sa tap35 and Sa tap44, from Sinapis alba L. are localized in the exine cell wall layer of developing microspores.

By differential screening of a copy DNA (cDNA) library from flowering Sinapis alba L. apices against cDNAs from vegetative apices, two cDNA clones were isolated representing transcripts that are expressed transiently at an early stage of tapetum development. The Sa tap35 cDNA encodes a polypeptide with a predicted molecular weight of 12.7 kDa and an isoelectric point of 10.4. The sa tap44 cDNA codes for a putative 12.4-kDa polypeptide with an isoelectric point of 7.5. The deduced amino-acid sequences display 76% sequence identity and contain an N-terminal stretch of hydrophobic amino acids which has characteristics of secretory signal sequences. In-vitro transcription of the cDNAs and translation of the resulting RNAs in the presence of canine pancreatic microsomes demonstrates that the two proteins are translocated into the microsomes and that the putative preproteins are proteolytically processed to the mature forms. By immunoelectron microscopy the Sa TAP35 and Sa TAP44 proteins were detected at the developing peritapetal membrane between the tapetal cytoplasm and the adjacent middle layer of the anther wall. Furthermore, labelling was observed within the locule in association with globules resembling pro-Ubisch bodies which appeared at the tetrad stage. During the early vacuolate stage of microspore development the young exine was strongly labelled. The exine and the peritapetal membrane both are composed of sporopollenin, and the pro-Ubisch bodies are thought to contain sporopollenin precursors. Thus, Sa TAP35 and Sa TAP44 might be involved in sporopollenin formation and/or deposition.

ATP-Binding Cassette Transporters↗
PubMed1994

[Perityphlitic abscess after perforated appendicitis with carcinoid of the appendix].

Appendix carcinoid in children is a rare condition which is found by accident at the histological examination of the appendix. We report on a rare case in which a covered perforation of a diverticulum had occurred. First of all the patient was treated conservatively with antibiotics and 2 months later the appendectomy à froid was performed. The annual follow-up of these patients is certainly indicated.

Abdominal Abscess↗
PubMed1994

Poly(ADP-ribose) polymerase activity in intact or permeabilized leukocytes from mammalian species of different longevity.

Poly(ADP-ribosyl)ation is a eukaryotic posttranslational protein modification catalyzed by poly(ADP-ribose) polymerase (PARP), a highly conserved nuclear enzyme which uses NAD as substrate. We have previously tested PARP activity in permeabilized mononuclear blood cells (MNC) from 13 mammalian species as a function of the species-specific life span. A direct and maximal stimulus of PARP activation was provided by including saturating amounts of a double-stranded oligonucleotide in the PARP-reaction buffer. The data yielded a strong positive correlation between PARP activities and the species' maximal life spans (r = 0.84; p << 0.001). Here, we investigated the formation of poly(ADP-ribose) in living MNC from two mammalian species with widely differing longevity (rat and man) by immunofluorescence detection of poly(ADP-ribose). The fraction of positive cells was recorded, following gamma-irradiation of intact MNC, as a semiquantitative estimation of poly(ADP-ribose) formation. Human samples displayed a significantly higher percentage of positivity than did those from rats, consistent with our previous results on permeabilized cells. While rat MNC had a higher NAD content than human MNC, the number of radiation-induced DNA strand breaks was not significantly different in the two species. Since poly(ADP-ribosyl)ation is apparently involved in DNA repair and the cellular recovery from DNA damage, we speculate that the higher poly(ADP-ribosyl)ation capacity of long-lived species might more efficiently help to slow down the accumulation of unrepaired DNA damage and of genetic alterations, as compared with short-lived species.

Animals↗
PubMed1994

From HIS to IAIMS: expanding the scope of information processing applications in a German university hospital.

Since the mid eighties the department of medical informatics at the University Hospital of Giessen (Germany) has been engaged in the development of a comprehensive hospital information system. The installation of a campus wide network has set the basis to provide not only clinical patient-oriented information, but also general information resources for research, medical education and administrative purposes, thus creating an environment which in the U.S. became known as an integrated academic information management system (IAIMS). The underlying concept of the whole approach is to provide one-stop information shopping capabilities at the clinicians and administrators desktop in order to meet the increasing information needs of health professionals with the emerging reality of the potential benefits of computer and communication technologies. This paper describes the various steps performed to realize this concept at Giessen University Hospital and the evaluation results derived from analysis of the acceptance of these new technologies among our hospital staff.

Computer Systems↗
PubMed1994

Pharmacological characterization of bosentan, a new potent orally active nonpeptide endothelin receptor antagonist.

The authors describe here the pharmacological properties of bosentan, a new nonpeptide mixed antagonist of endothelin (ET) receptors, obtained by structural optimization of the less potent Ro 46-2005 [Ro 46-2005 (4-tert-butyl-N-[6-(2-hydroxyethoxy)-5-(3-methoxy-phenoxy)-4-pyrimidinyl ]-benzenesulfonamide]. Bosentan (Ro 47-0203, 4-tert-butyl-N-[6-(2-hydroxy-ethoxy)-5-(2-methoxy-phenoxy)-2,2'-bipyr imidin-4-yl]-benzenesulfonamide) competitively antagonized the specific binding of [125I]-labeled ET-1 on human smooth muscle cells (ETA receptors) with a Ki of 4.7 nM and on human placenta (ETB receptors) with a Ki of 95 nM. It also inhibited the binding of selective ETB ligands on porcine trachea. Contractions induced by ET-1 in isolated rat aorta (ETA) and by the selective ETB agonist sarafotoxin S6C in rat trachea were competitively inhibited by bosentan (pA2 = 7.2 and 6.0, respectively), as was the endothelium-dependent relaxation to sarafotoxin S6C in rabbit superior mesenteric artery (pA2 = 6.7). The binding of 40 other peptides, prostaglandins, ions and neurotransmitters was not significantly affected by bosentan, which shows its specificity for ET receptors. In vivo, bosentan inhibited the pressor response to big ET-1 both after i.v. and oral administration, with a long duration of action and no intrinsic agonist activity. It also inhibited the depressor and pressor effect of ET-1 and sarafotoxin S6C. Thus, bosentan is the most potent orally active antagonist of ET receptors described so far. Its pharmacological profile makes bosentan a potentially useful drug in the management of clinical disorders associated with vasoconstriction.

Administration, Oral↗
PubMed1994

[Regulation of equilibrium in acute alcoholic intoxication with the craniocorpography method].

Twenty young male volunteers carried out a drinking experiment during which they underwent the Romberg standing test and the Unterberger treading test. These tests were carried out three times each in a sober state, 25 minutes and 2 hours after alcohol consumption. The balance tests were recorded, evaluated and documented by means of a Cranio-Corpo-Graphy. The Romberg standing test proved to be the more sensitive indicator of impaired balance, even when only slightly under the influence of alcohol. Both the degree of anterior-posterior and of lateral swaying increased according to the BAC and decreased after the end of absorption. Only lateral swaying was similarly recorded with the Unterberger test.

Adolescent↗
PubMed1994

[Infection with Mycoplasma mycoides ssp. mycoides LC (large colony type) in bezoar goat kids (Capra aegagrus cretica) in the Bern (Switzerland) Zoo].

Mycoplasma mycoides ssp. mycoides LC (large colony type) (MML) was isolated from three 2 to 6 weeks old wild goat kids (Capra aegagrus cretica) dead of septicemia in a Swiss zoo. Necropsy revealed peritonitis, pneumonia and enteritis. MML was isolated out of the ear canal of most of the healthy animals in the flock. The high density of the animals, the presence of concomitant diseases and the carriage among healthy animals seem to have been important predisposing factors for the MML-infection.

Animals↗
PubMed1994

Study on the influence of food on the absorption of theophylline from a controlled-release preparation.

The possible influence of food and fat content of meals on the bioavailability and pharmacokinetics of a 350 mg sustained-release theophylline (CAS 58-55-9) preparation (Bronchoretard) was investigated after single-dose oral administration to 18 volunteers in a randomized 3-way cross-over design. The treatments investigating an administration of the test preparation in a fasting state, after a standard meal and after a high-caloric fat evening meal, according to the commonly applied rules, could be shown to be equivalent with respect to the amount of bioavailability (AUC) and the observed maximal concentrations (Cmax). Pharmacokinetic parameters describing sustained-release characteristics were not changed either to any relevant degree. As expected, the co-administration of food resulted in a physiologically determined delay in absorption, which probably is not therapeutically relevant during long-term administration.

Adult↗
PubMed1994

p53 overexpression is frequent in European hepatocellular carcinoma and largely independent of the codon 249 hot spot mutation.

Mutations in the p53 tumour suppressor gene have been recently described in hepatocellular carcinomas (HCC) from high risk areas such as China and South Africa. Our study was designed to assess the importance of p53 aberrations in HCCs from Europe, where the major risk factors in hepatocarcinogenesis, aflatoxin exposure and chronic hepatitis B virus (HBV) infection, do not play a dominant role. We investigated 22 HCCs and, as controls, their corresponding tumour-free liver tissues, seven livers with primary biliary cirrhosis and four morphologically normal livers. p53 overexpression, which is usually associated with point mutations of the p53 gene, was detected in 10 of the 22 HCCs by immunoblotting and immunohistochemistry. p53 expression was restricted to the nucleus in the positive cells, while all cells in the control tissues were negative. There was no obvious etiological preference in the p53 positive tumours. Particularly, underlying chronic HBV infection did not appear to be associated with an increased rate of p53 overexpression in European HCCs. SSCP and sequence analysis of exons 5-8 of the p53 gene revealed point mutations in six out of eight tumours with increased steady state levels of p53. In conclusion, our study demonstrates increased p53 levels due to point mutations in a significant proportion of European HCCs. The codon 249 mutation, which was detected in one of the cases, is not predominant in these tumours.

Adult↗
PubMed1993

Nuclear magnetic resonance spectroscopy of a DNA complex with the uniformly 13C-labeled Antennapedia homeodomain and structure determination of the DNA-bound homeodomain.

A 1:1 complex formed by the mutant Antennapedia(C39S) homeodomain and a 14 base-pair DNA duplex (molecular weight approximately 18,000) was prepared in which the protein was uniformly 13C-labeled. Using two-dimensional nuclear Overhauser enhancement (NOE) spectroscopy with 13C(omega 1, omega 2)-double-half-filter and three-dimensional 13C-correlated NOE spectroscopy, nearly complete sequence-specific resonance assignments were obtained for both the protein and the DNA in the complex. On this basis conformational constraints needed for a three-dimensional structure determination were collected. Using 855 intramolecular distance constraints as input, the structure of the DNA-bound Antp(C39S) homeodomain was calculated with the program DIANA, followed by restrained energy minimization with the program OPAL. A group of 20 conformers characterizes a well-defined structure for residues 8 to 56, with an average of 0.5 A of the pairwise root-mean-square deviations calculated for the backbone atoms of the individual conformers relative to the mean coordinates. The quality of the resulting structure is comparable to the one for the free protein, and the global fold of the free Antp(C39S) homeodomain was found to be conserved in the DNA complex. The structure of the DNA-bound protein was the starting point for the subsequent structure determination of the complete Antp(C39S) homeodomain-DNA complex in solution.

Amino Acid Sequence↗
PubMed1993

Determination of the nuclear magnetic resonance solution structure of an Antennapedia homeodomain-DNA complex.

The nuclear magnetic resonance (NMR) solution structure of a complex formed by the mutant Antennapedia homeodomain with Cys39 replaced by Ser, Antp(C39S), and a 14 base-pair DNA duplex containing the BS2 operator sequence was determined using uniform 13C and 15N-labeling of the protein. Two-dimensional nuclear Overhauser enhancement spectroscopy ([1H,1H]NOESY) with 15N(omega 2)-half-filter and 13C(omega 1, omega 2)-double-half-filter, and three-dimensional heteronuclear-correlated [1H,1H]NOESY yielded a total of 855 intramolecular NOE upper distance constraints in the homeodomain, 151 upper distance constraints within the DNA duplex, and 39 intermolecular protein-DNA upper distance constraints. These data were used as the input for the structure calculation with simulated annealing followed by molecular dynamics in a water bath and energy refinement. A group of 16 conformers was thus generated which represent the solution structure of the Antp(C39S) homeodomain-DNA complex. The new structure determination confirms the salient features reported previously from a preliminary investigation of the same complex, in particular the location of the recognition helix in the major groove with the turn of the helix-turn-helix motif outside the contact area with the DNA, and the N-terminal arm of the homeodomain contacting the minor groove of the DNA. In addition, distinct amino acid side-chain-DNA contacts could be identified, and evidence was found that the invariant residue Asn51 (and possibly also Gln50) is in a slow dynamic equilibrium between two or several different DNA contact sites. The molecular dynamics calculations in a water bath yielded structures with hydration water molecules in the protein-DNA interface, which coincides with direct NMR observations of hydration waters. In the Appendix the experimental data obtained with the Antp(C39S) homeodomain-DNA complex and the techniques used for the structure calculation are evaluated using a simulated input data set derived from the X-ray crystal structure of a DNA complex with a homologous homeodomain. This study indicates that a nearly complete set of NOE upper distance constraints for the Antp(C39S) homeodomain and the protein-DNA interface was presently obtained. It further shows that the structure calculation used here yields a precise reproduction of the crystal structure from the simulated input data, and also results in hydration of the protein-DNA interface in the recalculated complex.

Animals↗
PubMed1993

The protein tyrosine kinase JAK1 complements defects in interferon-alpha/beta and -gamma signal transduction.

We have produced a cell line which lacks the protein tyrosine kinase JAK1 and is completely defective in interferon response. Complementation of this mutant with JAK1 restored the response, establishing the requirement for JAK1 in both the interferon-alpha/beta and -gamma signal transduction pathways. The reciprocal interdependence between JAK1 and Tyk2 activities in the interferon-alpha pathway, and between JAK1 and JAK2 in the interferon-gamma pathway, may reflect a requirement for these kinases in the correct assembly of interferon receptor complexes.

Animals↗
PubMed1993

Complementation by the protein tyrosine kinase JAK2 of a mutant cell line defective in the interferon-gamma signal transduction pathway.

Interferons (IFNs) alpha/beta (type I) and gamma (type II) bind to distinct cell surface receptors, inducing transcription of overlapping sets of genes by intracellular pathways that have recently attracted much attention. Previous studies using cell lines selected for their inability to respond to IFN-alpha (ref. 4) have shown that the protein kinase Tyk2 plays a central role in the IFN alpha/beta response. Here we report the isolation of the cell line gamma 1A, selected for its inability to express IFN-gamma-inducible cell-surface markers, that is deficient in all aspects of the IFN-gamma response tested, but responds normally to IFNs alpha and beta. The mutant cells can be complemented by the expression of another member of the JAK family of protein tyrosine kinases, JAK2 (refs 6-9). Unlike IFNs alpha and beta, IFN-gamma induces rapid tyrosine phosphorylation of JAK2 in wild-type cells, and JAK2 immunoprecipitates from these cells show tyrosine kinase activity. These responses are absent in gamma 1A cells. JAK2 is therefore required for the response to IFN-gamma but not to IFNs alpha and beta.

Animals↗