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M Baumann

Publications and source records attributed to M Baumann.

At least 199 records · Page 11Linked to original sources
PubMed1993

Regulation of IL-6 and the hepatic IL-6 receptor in acute inflammation in vivo.

The serum levels of interleukin 6 (IL-6) and the expression (mRNA) of the 80 kDa IL-6 receptor (IL-6R) were examined in three different models of acute inflammation. Rats were treated with either Freund's complete adjuvant (FA) via intraperitoneal injection, LPS via intravenous injection, or turpentine via subcutaneous injection. Using bio- and specific immunoassays, rat serum levels of IL-6, corticosterone, and acute phase proteins were quantified. LPS treatment induced the quickest and greatest serum IL-6 response (> 100 ng/ml within 3 h). In comparison, sera from turpentine and FA-treated rats contained much lower levels of IL-6 activity (< 10 ng/ml). Serum corticosterone levels increased by 3 h after injection in all three models, and equivalent raised serum levels of acute phase proteins were detected within 12-24 h. The expression of IL-6 receptor mRNA in hepatocytes increased markedly as early as 3 h after treatment and message levels began to decline by 6-12 h in all three models. To analyze the individual effects of raised corticosterone and IL-6 on the expression of hepatic IL-6R mRNA, rats were injected with either dexamethasone (Dex) or purified recombinant rat IL-6 (rIL-6) via intraperitoneal injection. Rats injected with rIL-6 showed highly induced IL-6R mRNA levels as early as 1 h after injection, and Dex-injected rats showed a significant but less dramatic rise in IL-6R message levels. Dex- or rIL-6-injected rats demonstrated a distinct profile of acute phase protein response different from that seen in the three experimental models. Regulation of IL-6R gene expression in the liver in vivo depends on a complex interaction between the hepatocyte and a combination of cytokines and other hormones.

Acute Disease↗
PubMed1993

The genus-specific lipopolysaccharide epitope of Chlamydia is assembled in C. psittaci and C. trachomatis by glycosyltransferases of low homology.

Chlamydiae possess a genus-specific epitope that is located on the lipopolysaccharide (LPS) and is composed of a 3-deoxy-D-manno-octulosonic acid (Kdo) trisaccharide of the sequence alpha Kdo-(2-->8)--alpha Kdo-(2-->4)-alpha Kdo. In Chlamydia trachomatis, this trisaccharide is biosynthetically generated through the action of a multi-functional Kdo-transferase encoded by the gene gseA. gseA of Chlamydia psittaci 6BC was cloned and expressed in a rough mutant (Re chemotype) of Escherichia coli (strain F515) that contains an LPS with only two alpha 2-->4-linked Kdo residues. Recombinant strains were able to add the immunodominant Kdo residue in alpha 2-->8-linkage to the parental LPS, as determined by SDS-PAGE and Western blot analysis using a monoclonal antibody against the genus-specific epitope. The DNA sequence of gseA was determined and aligned to that published recently for C. trachomatis serovar L2. Most surprisingly, the two deduced amino acid sequences shared only an overall homology of 67%. Thus, gseA exhibits species specificity at the DNA level, whereas its gene product results in the synthesis of a carbohydrate antigen with genus specificity.

Amino Acid Sequence↗
PubMed1993

Molecular comparison of the structural proteins encoding gene clusters of two related Lactobacillus delbrueckii bacteriophages.

Virulent phage LL-H and temperate phage mv4 are two related bacteriophages of Lactobacillus delbrueckii. The gene clusters encoding structural proteins of these two phages have been sequenced and further analyzed. Six open reading frames (ORF-1 to ORF-6) were detected. Protein sequencing and Western immunoblotting experiments confirmed that ORF-3 (g34) encoded the main capsid protein Gp34. The presence of a putative late promoter in front of the phage LL-H g34 gene was suggested by primer extension experiments. Comparative sequence analysis between phage LL-H and phage mv4 revealed striking similarities in the structure and organization of this gene cluster, suggesting that the genes encoding phage structural proteins belong to a highly conservative module.

Amino Acid Sequence↗
PubMed1993

Early inflammatory response of minocycline and tetracycline on the rabbit pleura.

The histopathologic findings were compared from 20 mg/kg intrapleural tetracycline hydrochloride (TCN) and three doses of intrapleural minocycline hydrochloride (5, 10, and 20 mg/kg) (MCN) in New Zealand white rabbits. Both TCN and MCN produced an early neutrophilic predominant pleural effusion that became mononuclear over 48 h. There was no difference in pleural fluid accumulation, number of adhesions, or histologically measured visceral and parietal pleural thickness between TCN and MCN (all p = ns). The TCN, 20 mg/kg, produced more visceral pleural plaque than MCN, 5 mg/kg (p < 0.05). Increasing MCN doses resulted in greater pleural fluid neutrophil accumulation. With higher dose MCN, greater mesothelial cell desquamation and fibroblast proliferation was evident compared to the 5 mg/kg dose. The MCN and TCN produce similar histopathologic condition in the rabbit pleura which suggests that MCN should cause a similar clinical response in humans.

Analysis of Variance↗
PubMed1993

[Adjuvant radiotherapy following radical prostatectomy--results, acute and late toxicity].

Between 1975 and 1987, 53 patients with radical retropubic prostatectomy for adenocarcinoma of the prostate (pathological stage C or D1) underwent adjuvant radiotherapy. 26 of these patients additionally underwent subcapsular orchiectomy. Radiation therapy was given to 45 patients as 40 to 50 Gy to the pelvic lymph nodes followed by a boost to the tumor bed to a total of 64 to 70 Gy. Only five of the 45 patients received treatment to prostate and pelvis developed progression, whereas four out of eight patients who were irradiated to the prostate alone showed progression (p < 0.01). The five- and ten-year disease-free survival rates of 33 patients with stage C tumors were 91% and 83%, the local control rate 97% and 94%. 20 patients with stage D1 carcinoma showed a five-year disease-free survival of 79% and a local control rate of 95%. 25/26 patients with subcapsular orchiectomy are living disease-free, 8/27 patients without hormonal manipulation had a progression of disease (p < 0.05). All 13 patients with well or moderate differentiated tumor are alive without evidence of disease, 9/40 patients with poor differentiated carcinoma have shown tumor progression (p < 0.05). Compared to published results, our data suggest, that adjuvant radiotherapy can decrease local recurrence and probably increase disease-free survival in stage C and D1 carcinoma of the prostate.

Adenocarcinoma↗
PubMed1992

Enzymatic defect in "X-linked" sideroblastic anemia: molecular evidence for erythroid delta-aminolevulinate synthase deficiency.

Recently, the human gene encoding erythroid-specific delta-aminolevulinate synthase was localized to the chromosomal region Xp21-Xq21, identifying this gene as the logical candidate for the enzymatic defect causing "X-linked" sideroblastic anemia. To investigate this hypothesis, the 11 exonic coding regions of the delta-aminolevulinate synthase gene were amplified and sequenced from a 30-year-old Chinese male with a pyridoxine-responsive form of X-linked sideroblastic anemia. A single T----A transition was found in codon 471 in a highly conserved region of exon 9, resulting in an Ile----Asn substitution. This mutation interrupted contiguous hydrophobic residues and was predicted to transform a region of beta-sheet structure to a random-coil structure. Prokaryotic expression of the normal and mutant cDNAs revealed that the mutant construct expressed low levels of enzymatic activity that required higher concentrations of pyridoxal 5'-phosphate to achieve maximal activation than did the normal enzyme. The amino acid substitution occurred in the exon containing the putative pyridoxal 5'-phosphate binding site and may account for the reduced ability of the cofactor to catalyze the formation of delta-aminolevulinic acid.

5-Aminolevulinate Synthetase↗
PubMed1992

Subunit interactions of GTP-binding proteins.

Fluorescence energy transfer [cf. Förster, T. (1948) Ann. Phys. 6, 55-75] was tested for its suitability to study quantitative interactions of subunits of G0 with each other and these subunits or trimeric G0 with the beta 1-adrenoceptor in detergent micelles or after reconstitution into lipid vesicles [according to Feder, D., Im, M.-J., Klein, H. W., Hekman, M., Holzhöfer, A, Dees, C., Levitzki, A., Helmreich, E. J. M. & Pfeuffer, T. (1986) EMBO J. 5, 1509-1514]. For this purpose, alpha 0- and beta gamma-subunits and trimeric G0 purified from bovine brain, the beta gamma-subunits from bovine rod outer segment membranes and the beta 1-adrenoceptor from the turkey erythrocyte were all labelled with either tetramethylrhodamine maleimide or fluorescein isothiocyanate under conditions which leave the labelled proteins functionally intact. In the case of alpha 0- and beta gamma-interactions, specific high-affinity binding interactions (Kd approximately 10 nM) and nonspecific low-affinity binding interactions (Kd approximately 1 microM) could be readily distinguished by comparing fluorescence energy transfer before and after dissociation with 10 microM guanosine 5'-O-[gamma-thio]triphosphate and 10 mM MgCl2 where only low-affinity binding interactions remained. Interactions between alpha 0- and beta gamma-subunits from bovine brain or from bovine retinal transducin did not differ much. The beta gamma-subunits from bovine brain were found to bind with high transfer efficiency and comparable affinities to the hormone-activated and the nonactivated beta 1-receptor reconstituted in lipid vesicles: Kd = 100 +/- 20 and 120 +/- 20 nM, respectively; however, beta gamma-subunits from transducin appeared to bind more weakly to the beta 1-adrenoceptor than beta gamma-subunits from bovine brain. Separated purified homologous alpha 0- and beta gamma-subunits from bovine brain interfered mutually with each other in binding to the beta 1-adrenoceptor presumably because they had a greater affinity for each other than for the receptor. These findings attest to the suitability of fluorescence energy transfer for studying protein-protein interactions of G-proteins and G-protein-linked receptors. Moreover, they supported the previous finding [Kurstjens, N. P., Fröhlich, M., Dees, C., Cantrill, R. C., Hekman, M. & Helmreich, E. J. M. (1991) Eur. J. Biochem. 197, 167-176] that beta gamma-subunits can bind to the nonactivated beta 1-adrenoceptor.

Animals↗
PubMed1992

A novel polymorphism of apolipoprotein A-IV is the result of an asparagine to serine substitution at residue 127.

We have identified a hitherto unknown genetic polymorphism of apolipoprotein A-IV (apoA-IV). The molecular basis for this polymorphism is an A to G substitution at nucleotide 1687 resulting in an Asn to Ser change of amino acid 127. The frequencies of the two apoA-IV alleles (designated apoA-IV127Asn and apoA-IV127Ser), determined by Hin c II restriction analysis of PCR amplified exon three of the apoA-IV gene, were 0.788 and 0.212, respectively, in a Finnish population sample. Allele frequencies of another polymorphism due to a Thr to Ser substitution at amino acid 347 were determined using Hinf I restriction analysis. The allele frequencies were 0.823 for apoA-IV347Thr and 0.177 for apoA-IV347Ser. None of the apoA-IV polymorphisms (apoA-IV127:Asn----Ser, apoA-IV347:Thr----Ser and apoA-IV360:Gln----His) had any effect on plasma lipid and lipoprotein concentrations in cohorts of dyslipidemic men and in a population sample of normolipidemic controls. There was also no association between the history of previous myocardial infarction and any of the apoA-IV alleles.

Alleles↗
PubMed1992

Nucleotide sequence of the 3'-terminal region of potato virus A RNA.

The sequence of the 3'-terminal region of the genome of the potato virus A (PVA) was obtained from two independent cDNA clones. This sequence is 1383 nucleotides long and contains an open reading frame of 1178 nucleotides, ending with the translation termination codon TAA and followed by untranslated region of 205 nucleotides. Since the N-terminal amino acid of the coat protein of PVA was blocked, the position of the putative coat protein cleavage site has been deduced by searching for consensus sequences and by the analogy to other potyviruses. The resulting coat protein is 269 amino acids long and has a calculated MW of 30257. Two independently sequenced cDNA clones show sequence heterogeneity at four nucleotide positions: C422/A422, G432/A432, G446/A446 and T706/C706. Three first nucleotide differences are located at the PVA coat protein N-terminal region and led to the change of the amino acid. The coat protein of PVA displayed significant (73-78%) sequence homology to the coat proteins of six other potyviruses: papaya ringspot virus (PRV), pepper mottle virus (PeMV), plum pox virus (PPV), potato virus Y (PVY), sugarcane mosaic virus (SCMV) and tobacco vein mottling virus (TVMV). Even higher sequence homology (82%) was detected with a coat protein of a seventh potyvirus, tobacco etch virus (TEV). Major differences among the coat protein of PVA and of other potyviruses are located at the N-terminal region of the coat protein.

Amino Acid Sequence↗
PubMed1992

Response of xenografts of human malignant gliomas and squamous cell carcinomas to fractionated irradiation.

The response of xenografts of five human malignant glioma cell lines and two human squamous cell carcinomas to fractionated irradiation was studied. For this, the tumors were transplanted into nude mice which had been further immunosuppressed by 6 Gy whole-body irradiation. Radiation was given as 30 fractions applied under normal blood flow conditions in two sessions per day over 15 days. Absolute and specific tumor growth delay after 48 Gy, and tumor control dose 50% (TCD50) were evaluated. Using local tumor control as experimental endpoint, four out of five malignant gliomas were more resistant to fractionated radiation therapy than the two squamous cell carcinomas. The TCD50s of these four gliomas ranged from 73 Gy to more than 120 Gy, whereas the TCD50s of the squamous cell carcinomas were 51 and 60 Gy. Absolute tumor growth delay correlated well with TCD50, but no correlation was obtained between specific growth delay and TCD50. The response of the human tumor xenografts in vivo did not correlate with the surviving fractions at 2 Gy of the same cell lines in vitro which have been previously obtained in our laboratory. The results suggest that the unique radioresistance observed in malignant gliomas in patients is at least in part reflected in human tumor xenografts. The lack of correlation between the surviving fraction at 2 Gy in vitro and the tumor response in vivo could be a consequence of an immune response by the host, a difference in cell radiation sensitivity between cell lines and xenografted tumors, or of differences of parameters such as hypoxic fraction, rate of repopulation, and cell cycle effects between the different tumor lines studied. It illustrates the difficulties which might be involved in the prediction of the response of individual tumors to radiation therapy based solely on the intrinsic radiosensitivity of the tumor cells as assayed by in vitro assays of colony formation.

Animals↗
PubMed1992

Staining of surface antigens of Chlamydia trachomatis L2 in tissue culture.

Surface labeling of chlamydial elementary and reticulate bodies in L929 cells infected with Chlamydia trachomatis serotype L2 was monitored by using monoclonal antibodies (MAb) against the major outer membrane protein and lipopolysaccharide (LPS). Different staining and fixation procedures were used to detect these surface antigens during the developmental cycle. Anti-major outer membrane protein MAb yielded a clear staining pattern of exclusively chlamydial inclusions independent of the fixation or staining technique used. Anti-LPS MAb gave a faint staining pattern of reticulate bodies when methanol fixation was used and showed that LPS was released from chlamydiae into the host cell cytoplasm and into the surroundings of the infected host cell. However, when paraformaldehyde-glutardialdehyde fixation was used, extracellular LPS staining was not observed. The data show that chlamydial LPS is loosely bound in the bacterial outer membrane but suggest that shedding of LPS is a fixation artifact.

Antibodies, Monoclonal↗
PubMed1992

A synthetic glycoconjugate representing the genus-specific epitope of chlamydial lipopolysaccharide exhibits the same specificity as its natural counterpart.

The tetrasaccharide 3-deoxy-alpha-D-manno-2-octulosonic acid (alpha-KDO) (2----8)-alpha-KDO(2----4)-alpha-KDO(2----6)-beta GlcNAc, a partial structure of chlamydial lipopolysaccharide (LPS) representing a genus-specific epitope, was synthesized and covalently linked to bovine serum albumin, resulting in an artificial glycoconjugate antigen. Mice were immunized with the glycoconjugate to prepare chlamydia-specific monoclonal antibodies. They were selected with chlamydia-specific LPS antigens and the structurally and antigenically related Re-type LPS of a Salmonella minnesota rough mutant. Characterization of the selected antibodies was by (i) hemagglutination of sheep erythrocytes coated with recombinant chlamydia-specific LPS, (ii) inhibition by synthetic polyacrylamide derivatives containing the genus-specific epitope or partial structures thereof, (iii) enzyme immunoassay with recombinant LPS and synthetic bovine serum albumin glycoconjugates as solid-phase antigens, (iv) immunofluorescence of L929 monolayers infected with Chlamydia psittaci or C. trachomatis, and (v) Western immunoblots with glycoconjugates and LPS as the antigen. Two groups of monoclonal antibodies were obtained; the monoclonal antibodies in one group cross-reacted with chlamydial and Re-type LPS, but those of the other group were chlamydia specific. Among the latter, KDO trisaccharide-specific antibodies that had the same epitope specificity as antibodies obtained after immunization with chlamydial elementary bodies were identified; however, they exhibited a more than 100-fold higher affinity. In addition, antibodies that bound preferentially to the 2.8-linked KDO disaccharide were detected, although with lower affinity. The data show that the artificial glycoconjugate antigen is similar to its natural counterpart.

Animals↗
PubMed1992

Growth and characterization of fibroblasts obtained from bronchoalveolar lavage of patients with scleroderma.

We describe the detection and the growth of fibroblasts with human smooth muscle cell differentiation features from bronchoalveolar lavage (BAL) fluid of 53% of patients with scleroderma, but not from healthy controls. The binding of alpha-actin, vimentin and desmin antibodies by scleroderma lung fibroblasts exceeded that of normal adult lung fibroblasts, indicating that scleroderma lung fibroblasts express some markers of human smooth muscle cell differentiation (myofibroblasts), which may account for differences in biological behavior. A mesenchymal cell phenotype was documented by mRNA analysis, showing high expression of collagen type I and fibronectin in these cells. Fibronectin is also released in significantly higher amounts by scleroderma alveolar macrophages than by macrophages from healthy donors.

Actins↗
PubMed1992

[The hyperfractionated radiotherapy of tumors in the head-neck area].

This paper provides a survey on investigations that deal with the effects of hyperfractionation. The influence of relevant parameters on treatment results is explained. Furthermore, clinically practicable hyperfractionated treatment schedules for therapy of head and neck tumours are proposed. Clinical and experimental reports reveal that with hyperfractionation two strategies can be realised: 1. Late normal tissue reactions can be reduced without changing total dose. In this case local tumour control rate remains unchanged. 2. To enhance tumour control rates a higher total dose can be administered, if late reactions were dose limiting in the reference schedule. In this case a reduced dose per fraction and an appropriately increased total dose will leave late reactions unchanged. Applying two fractions per day the dose per fraction should not exceed 1.4 Gy. Otherwise severe acute reactions could require treatment interruption. A time interval of at least six hours between fractions reduces the risk of acute and late reactions considerably.

Head and Neck Neoplasms↗
PubMed1991

Human leucocyte aspartylglucosaminidase. Evidence for two different subunits in a more complex native structure.

Human leucocyte aspartylglucosaminidase (AGA: 1-aspartamido-beta-N-acetylglucosamine amidohydrolase, EC 3.5.1.26) was purified to homogeneity by using affinity chromatography, gel filtration, chromatofocusing and reverse-phase h.p.l.c. As shown by SDS/PAGE, the homogeneous purified enzyme preparation consists of four polypeptide chains with molecular masses of 25, 24, 18 and 17 kDa. In the native polyacrylamide gel these polypeptides migrate as one active enzyme complex, and by gel filtration the peak of enzyme activity can be detected in a position of about 65 kDa. Digestion with endoproteinase Lys-C or endoproteinase Asp-N, followed by peptide analysis with reverse-phase h.p.l.c., reveals an identical peptide pattern for the 24 and 25 kDa bands as well as for the 17 and 18 kDa bands. This treatment further demonstrated a totally different peptide pattern for the 24/25 kDa versus the 17/18 kDa subunit. The N-terminal sequences of the 17 kDa and the 18 kDa peptides were identical, as determined by Edman degradation. The N-termini of the 24 kDa and the 25 kDa peptides were blocked. The enzyme was partly resistant to endoglycosidases H and F, but N-glycosidase F transformed the 24/25 kDa band into one 23 kDa band and the 17/18 kDa band into one 16 kDa band. Also, immunological data obtained with antisera produced against these subunits showed that AGA consists of two non-identical polypeptides.

Amino Acid Sequence↗
PubMed1991

Amino-terminal sequence analysis of four plasmid-encoded virulence-associated proteins of Salmonella typhimurium.

We have expressed four virulence-associated proteins encoded by the Salmonella typhimurium plasmid pEX102 in Escherichia coli. The genes coding for the proteins MkaA, MkaB, MkaC and MkaD subcloned in the vectors pUC19 or Bluescript KS+ directed substantial production of these proteins in E. coli. The same host harbouring pEX102 did not produce these proteins in detectable amounts. The proteins were exclusively found in the particulate fraction. The amino-terminal sequence analysis showed that the N-termini of these proteins corresponded to the ones predicted from the open reading frames found previously in the DNA sequence of the virulence determinant and that no N-terminal signal sequence processing of the proteins occurred.

Amino Acid Sequence↗