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Biomedical subjects

D Bauer

Publications and source records attributed to D Bauer.

At least 19 recordsLinked to original sources
PubMed1992

A 41.7 kDa serine protease from Clostridium perfringens type A: degradation of purified human serum proteins.

Two clinical isolates of Clostridium perfringens type A produced a novel caseinolytic serine protease. Both enzymes had a molecular weight of 41.7 kilodaltons and an isoelectric point of 9.1. The two enzymes were immunogenic for rabbits and closely related serologically. Both enzymes partially degraded the heavy chains of human immunoglobulins (Ig) G and IgM, but not IgA. Purified human complement (C) components C3, C5, C8, and C9 were attacked; C1q was refractory. Both enzymes were active against human transferrin, alpha 1-antitrypsin, alpha 2-macroglobulin, haptoglobin, type III fibrinogen, and fibronectin. C-reactive protein was refractory.

Blood Proteins↗
PubMed1992

Ankle reconstruction for malunion by fibular osteotomy and lengthening with direct control of the distal fragment: a report of three cases and review of the literature.

Malunion of ankle fractures will lead to severe osteoarthritis when the architecture and mechanics of the talocrural joint are deranged. When fibular shortening is present, ankle reconstruction can be achieved by fibular lengthening and can provide an alternative to early arthrodesis for deformity and pain. Acceptable clinical and radiographic results can be achieved, provided that accurate reconstruction is achieved and intra-articular osteochondral injury is minimal. Restoration of fibular length, necessary for a good clinical result, can be estimated radiographically by the bimalleolar angle. We report three cases of ankle reconstruction by fibular lengthening with an average follow-up of 33 months.

Adult↗
PubMed1991

Metalloproteases of Serratia liquefaciens: degradation of purified human serum proteins.

Two representative strains of Serratia liquefaciens, SL 5 (serotype O5:H1) and SL 11 (serotype O1:H1), produced proteases characterized by molecular weights of 52.5 kilodaltons and isoelectric points of 6.2; both enzymes were inhibited by 50 mM EDTA. As demonstrated with SDS-PAGE electrophoresis, the two metalloproteases attacked the following purified human serum proteins: complement components C3, C4, C5, C6, C7, C8, and C9, transferrin, alpha 1-antitrypsin, alpha 2-macroglobulin, fibronectin, type III fibrinogen, immunoglobulin G (heavy chains), and IgM (heavy chains). However, C1q, IgA, haptoglobin, and C-reactive protein were refractory.

Blood Proteins↗
PubMed1991

Collagenase of Clostridium perfringens type A: degradation of human complement component C1q.

The semipurified collagenases from Clostridium perfringens type A strains 2-Cli and ATCC 13124, both characterized by molecular weights of 79.4 kilodaltons, partially degraded purified human complement (C) component C1q. The following purified human serum proteins were refractory: C components C3, C4, C5, C6, C7, C8, and C9; immunoglobulin (Ig)A (from colostrum), IgG, and IgM; alpha 2-macroglobulin, haptoglobin, and C-reactive protein.

Blotting, Western↗
PubMed1991

Teicoplanin combined with various antibiotics and human blood against a multiple-drug-resistant strain of Staphylococcus aureus.

Neither teicoplanin nor vancomycin at 2, 1 and 0.5 micrograms/ml consistently killed inocula of representative isolates of a multiple-drug-resistant (MDR) strain of Staphylococcus aureus in the presence of 65% (v/v) of fresh, defibrinated human blood, although both antibiotics sterilized tube contents in Mueller-Hinton broth (MHB). With added human blood, teicoplanin (1 microgram/ml) combined with rifampin (1 microgram/ml) was the most effective in vitro combination, followed by teicoplanin (1 microgram/ml) + amoxicillin (8 micrograms/ml) + clavulanate (3 micrograms/ml), ampicillin (8 micrograms/ml) + sulbactam (8 micrograms/ml), cefamandole (8 micrograms/ml), fosfomycin (4 micrograms/ml + 25 micrograms/ml glucose-6-phosphate), imipenem (8 micrograms/ml), netilmicin (4 micrograms/ml), trimethoprim + sulfamethoxazole (1/19 micrograms/ml) and vancomycin (1 microgram/ml), respectively. Conversely, teicoplanin (1 microgram/ml) combined with fusidic acid (0.5 micrograms/ml) and ofloxacin (4 micrograms/ml), respectively, proved ineffective with 65% (v/v) added human blood. In concurrent control tubes, however, all drug combinations were bactericidally active in MHB against the MDR strain of S. aureus.

Aminoglycosides↗
PubMed1991

Immunobiology of Clostridium perfringens type A: passive protection of NMRI mice. Western blot analysis of immunoreactive polypeptides.

Polyvalent, equine antitoxin (250 IU/mouse) passively protected NMRI mice against 7 of 9 challenge strains of Clostridium perfringens type A. Two human immunoglobulin G (IgG) preparations (Polyglobin N and Sandoglobulin) and two rabbit immune sera prepared against formalinized cells of C. perfringens were ineffective. Cell homogenates of 4 C. perfringens strains revealed more than 15 polypeptides in SDS-PAGE electropherograms; the molecular weights ranged from 138 to 14.4 kD. Normal human serum from 2 donors revealed up to 3 immunoblot-reactive antibodies against 126-, 69.2-, 49- or 14.4-kD antigens, the two rabbit immune sera showed antibodies against 4-7 distinct antigens that ranged from 138 to 28.8 kD, whereas the two human IgG preparations revealed antibodies against up to 12 antigens (range 138.7-31.6 kD) and antibodies against lower-molecular-weight (less than 24.5-kD) components. Polyvalent, equine antitoxin reacted with at least 14 polypeptides (range 136.5-31 kD) and numerous smaller (less than 24-kD) components.

Animals↗
PubMed1991

Virulence of clinical and fecal isolates of Clostridium perfringens type A for outbred NMRI mice.

Twelve clinical and 102 fecal isolates from healthy carriers of Clostridium perfringens type A were tested for virulence in juvenile, outbred NMRI mice (intramuscular route). There were marked differences (up to 1,000-fold) in virulence among strains of both groups of isolates. On average, clinical isolates were not more virulent than fecal isolates. Fresh epinephrine (10 micrograms/mouse and given concurrently with bacterial inocula) significantly augmented virulence. The murine model of Hill and Osterhout for experimental gas gangrene yielded reproducible results. Myelosuppressed (cyclophosphamide-pretreated) mice were somewhat more susceptible to C. perfringens as contrasted with mice that had been pretreated with either carrageenan type II or with zymosan. The murine virulence of C. perfringens was enhanced significantly by Escherichia coli.

Animals↗
PubMed1990

Isolation from adult human serum of four insulin-like growth factor (IGF) binding proteins and molecular cloning of one of them that is increased by IGF I administration and in extrapancreatic tumor hypoglycemia.

We have isolated four insulin-like growth factor binding proteins (IGFBPs) from adult human serum by insulin-like growth factor (IGF) I affinity chromatography and high performance liquid chromatography. A 36-kDa binding protein (BP), not digestible with N-glycanase, is increased in patients with extrapancreatic tumor hypoglycemia and during IGF I administration in healthy adults. Its 38 NH2-terminal amino acids are identical to those of an IGFBP sequence derived from a human cDNA that cross-hybridizes with the rat IGFBP-2 cDNA. With probes encoding a NH2-terminal, COOH-terminal, and a middle region of this protein we have obtained three cDNA clones from a Hep G2 cDNA library; one encodes human IGFBP-2, and the other two presumably represent unspliced heteronuclear and alternatively spliced mRNA, respectively. A 28-30-kDa IGFBP represents a novel BP species in human serum. Its 30 NH2-terminal amino acids are not homologous to IGFBP-1, -2, or -3. It is not digestible with N-glycanase and does not bind 125I-IGF I. The NH2-terminal sequences of a 42/45- and a 31-kDa IGFBP are identical to that of human IGFBP-3. The 42/45-kDa proteins are two glycosylation variants of BP-3. The 31-kDa protein presumably is a degradation product of BP-3 that lacks the COOH terminus. It is likely that the different IGFBPs modulate auto-/paracrine and endocrine effects of IGFs on growth and metabolism in a different and specific manner.

Adult↗
PubMed1990

Cloning and characterization of cDNAs for murine macrophage inflammatory protein 2 and its human homologues.

A cDNA clone of murine macrophage inflammatory protein 2 (MIP-2) has been isolated from a library prepared from lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and the nucleotide sequence determined. This cDNA was used to clone cDNAs for human homologues of MIP-2 from a library prepared from phorbol myristate acetate-treated and LPS-stimulated U937 cells. Two homologues were isolated and sequenced. Human MIP-2 alpha and MIP-2 beta are highly homologous to each other and to a previously isolated gene, human gro/melanoma growth-stimulating activity (MGSA). These three human genes, MIP-2 alpha, MIP-2 beta, and gro/MGSA, constitute a sub-family within the cytokine family represented by platelet factor 4 and interleukin 8.

Amino Acid Sequence↗
PubMed1990

Epoxide hydrolase, its function and determination of its activity in rat liver.

Epoxides are a group of reactive intermediates formed by the cytochrome P-450-mediated monooxygenation of unsaturated xenobiotics. Epoxide hydrolase inactivates these epoxides by addition of water to form diols. Commonly the function of epoxide hydrolase is finally followed by excretion of the diols. However, reactivation of certain diols by a second epoxidation may happen. Epoxide hydrolase inactivates also the epoxides existing in the metabolism of endogenous compounds. The determination of the activity of epoxide hydrolase by the addition of water to styrene oxide (1,2-epoxyethylbenzene) and measurement of the concentration of the produced phenylglycol (1-phenyl-1,2-ethandiol) with subsequent separation of the 2 substances by HPLC is described. Lipophilic xenobiotics tend to accumulate into tissues, and they must be transformed to water soluble compounds to enable the excretion. In this transformation process reactive intermediates are produced. If biotransformation fails to detoxify these reactive intermediates, they may react covalently with critical targets like the genetic material, or start harmful reaction chains like lipid peroxidation. As a result of this carcinogenicity, mutagenicity etc. may ensue Miller and Miller (1976). Depending on the chemical structure of the molecule, different kinds of reactive substances are generated. Epoxides originate from oxidation of an aliphatic or aromatic double bond by the action of cytochrome P-450-mediated monooxygenases (Leibmann et al. 1979). One detoxifying pathway is the addition of water to form diols, which are of low reactivity; this reaction is catalyzed by epoxide hydrolase. Other possible pathways are the formation of glutathione conjugates or the rearrangement to aldehydes or ketones (Habig et al. 1974; Oesch 1979).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Humoral antibody response of rabbits against experimental Serratia marcescens septicemia.

Rabbits reconvalescent from experimental septicemia due to serologically defined strains of Serratia marcescens were examined for the diversity of their humoral antibody response with traditional serological procedures and the Western blot (immunoblotting) technique. Trichloracetic acid (TCA)-whole cell extracts of the homologous and heterologous O-antigen reference strains served as the antigen for the latter procedure. Reconvalescent rabbit sera contained antibodies against the homologous lipopolysaccharide (LPS) moiety (molecular weight (MW) range = 45-31 kilodaltons (= k] and antibodies against numerous heat-modifiable, cross-reactive proteins, in particular 7 proteins characterized by MWs of 117 k, 95 k, 91 k, 71 k, 68 k, 38 k, and 33 k in TCA-whole cell extracts from the homologous as well as from 11 heterologous S. marcescens O-antigen reference strains. Rabbits, which had been actively immunized with TCA-whole cell extracts from representative S. marcescens strains, mounted a humoral antibody response remarkably similar to that of rabbits which had recovered from septicemia, except that the sera from the actively immunized animals interacted somewhat more strongly with an additional cross-reactive protein (MW = 47 k). Conversely, conventional anti-O and anti-H rabbit immune sera revealed antibodies directed predominantly against the homologous LPS moiety (MW range = greater than or equal to 200 k - less than or equal to 15 k). It was concluded that numerous proteinaceous cellular constituents of S. marcescens accounted for immunoblot cross-reactivity.

Animals↗
PubMed1990

Human immunodeficiency virus type 1 cellular host range, replication, and cytopathicity are linked to the envelope region of the viral genome.

Human immunodeficiency virus type 1 (HIV-1) isolates vary in their in vitro biologic characteristics such as cellular host range, replication kinetics, and cytopathicity. In this study, we molecularly exchanged equivalent regions between two cloned HIV-1 isolates with differing replicative and cytopathic properties. To facilitate generation of recombinant viruses, we used a method involving cotransfection of human monolayer cells with plasmid constructs containing half of the biologically active viral genome. The two halves of the genome were subsequently ligated by intracellular processes to form the complete proviral genome. This method simplifies plasmid construction, since new infectious virus particles can be produced easily from the individual constructs that are correctly ligated in vivo. Results obtained by using recombinant viruses generated in this manner indicate that the ability of HIV to replicate in specific cell types and cytopathicity segregate with the env region of the viral genome.

Amino Acid Sequence↗
PubMed1990

Recombinants from a proviral bovine leukemia virus genome corresponding to the 3' region transactivate viral LTR in NIH3T3 and non-infected FLK cells.

Bovine leukemia virus (BLV), like human T-cell leukemia viruses, Types I and II, contains three open reading frames at the 3' end of its genome. The longest open reading frame encodes a transactivator protein which is generated by a doubly-spliced mRNA. A series of co-transfection experiments, using proviral BLV pX expression plasmids under the control of the Moloney leukemia virus LTR and the indicator plasmid containing the assayable lac Z gene under the control of BLV LTR, revealed that both NIH3T3 cells and non-infected fetal lamb kidney cells are able to express an active transactivator protein.

Animals↗
PubMed1990

[Anti-radical enzymes, oxygenated free radicals and lipoperoxydation in rheumatoid polyarthritis. Effects of treatment with D-penicillamine].

Three aspects of the action of oxygenated free radicals were studied in 10 controls and 20 patients with rheumatoid arthritis, 11 not treated and 9 treated with D-penicillamine. Free radical production was evaluated in whole blood, malondialdehyde was measured in plasma, the concentration of antiradicular enzymes (copper and manganese superoxide dismutase, catalase and glutathion peroxydase) in hemolysate, platelets and plasma and copper superoxide dismutase activity in a chloroform erythrocyte extract. Only patients treated with D-penicillamine showed a significant decrease in the concentration of platelet anti-radicular enzymes and plasma manganese superoxide dismutase. The involvement of oxygenated free radicals in the pathophysiology of rheumatoid arthritis and in the mechanism of action of D-penicillamine in this pathology is discussed.

Arthritis, Rheumatoid↗
PubMed1989

Molecular cloning of human myelin-associated glycoprotein.

The nucleotide sequence for human myelin-associated glycoprotein (MAG) and its deduced amino acid sequence, obtained by analysis of two overlapping cDNA clones isolated from a human brain cDNA library, is presented and compared to that reported for rat MAG. The sequence provides an open reading frame of 1,878 nucleotides encoding a peptide of 626 amino acids with a calculated molecular weight of 69.1 kD. It is 89% homologous in nucleotide sequence to the large isoform of rat MAG, with 95% homology in the amino acid sequence. It contains 9 potential glycosylation sites, one more than in rat, and shares other key features with rat MAG, including 5 immunoglobulin-like regions of internal homology, an RGD sequence, and potential phosphorylation sites. Its structure appears to be highly conserved in evolution, possibly suggesting a close interdependence between its structure and function. The human gene is located on the proximal long arm of chromosome 19 (19q12----q13.2).

Amino Acid Sequence↗