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Biomedical subjects

G Peters

Publications and source records attributed to G Peters.

At least 289 records · Page 16Linked to original sources
PubMed1983

Numerical taxonomy of staphylococci.

Over two hundred staphylococci from human and animal sources and representatives of established species of Staphylococcus, Micrococcus and Planococcus were compared in a numerical phenetic survey using 115 unit characters. Data were analyzed using the Jaccard coefficient and the unweighted pair group method with averages algorithm. Cluster composition was not markedly affected by test error, estimated as 3.49%. The staphylococci were assigned to eighteen clusters containing four or more strains and to three single member clusters. Most of the clusters were distinct and homogeneous though two were divided into subclusters. Some of the clusters and subclusters were equated with the established taxa S. aureus, S. capitis, S. cohnii, S. epidermidis, S. haemolyticus, S. hominis, S. hyicus, S. saprophyticus, S. sciuri subspecies lentus, S. sciuri subspecies sciuri, S. simulans, S. warneri and S. xylosus, the remaining ones may represent the nuclei of additional centres of variation. The numerical data also cast doubts upon the reliability of some of the tests recommended for the identification of coagulase-negative staphylococci.

Computers↗
PubMed1983

Microbial colonization of prosthetic devices. V. attachment of coagulase-negative staphylococci and "slime"-production on chemically pure synthetic polymers.

On 12 different, chemically pure polymers attachment and "slime"-production of the coagulase-negative staphylococcal strain KH 11 were studied. According to their behaviour the polymers investigated could be arranged into three groups: Group 1 with good attachment of staphylococci, but missing "slime"-production; group 2 with good attachment and moderate "slime"-production; group 3 with both properties strongly developed. According to the results presented, attachment of staphylococci and "slime"-production seem to be independent of the presence of organic additives in biomaterials.

Adhesiveness↗
PubMed1982

Adherence and growth of coagulase-negative staphylococci on surfaces of intravenous catheters.

Colonization of intravenous catheters by coagulase-negative staphylococci was followed by scanning electron microscopy. Regular sampling of specimens demonstrated adhesion of the staphylococci to the catheter surface followed by cell proliferation, possible breakdown of catheter components, and production of a slimy material covering the bacterial colonies. The implications of these findings with reference to nosocomial infections of prosthetic devices are discussed.

Adhesiveness↗
PubMed1982

Conservation of protein coding potential in the long terminal repeats of exogenous and endogenous mouse mammary tumor viruses.

In vitro protein synthesis and DNA sequence analysis indicate that mouse mammary tumor virus differs from other well-characterized retroviruses in that the long terminal repeat region of the provirus has the capacity to encode proteins. Different exogenously transmitted mouse mammary tumor virus strains and endogenous proviral units conserved this open reading frame feature in the long terminal repeat despite a variation in nucleotide sequence. The proteins encoded by the different long terminal repeats were clearly related, but showed minor variations in size and tryptic peptide maps. In each case, the largest in vitro product had a molecular weight of about 36,000 to 37,000, suggesting that the open reading frame sequences must extend for approximately 1,000 nucleotides beginning at the extreme 5' end of the long terminal repeat. The fact that the reading frame was conserved among these viruses argues in favor of an in vivo function for the open reading frame protein.

DNA, Recombinant↗
PubMed1982

FBJ murine osteosarcoma virus: identification and molecular cloning of biologically active proviral DNA.

A 12.0-kilobase EcoRI restriction fragment containing FBJ murine osteosarcoma virus (FBJ-MSV) proviral DNA was identified in FBJ-MSV-transformed nonproducer rat cells and molecularly cloned in bacteriophage Charon 30 (lambda FBJ-1). A 5.8-kb HindIII fragment containing the entire FBJ-MSV proviral DNA was isolated from lambda FBJ-1 and subsequently subcloned in plasmid pBR322 (pFBJ-2). The DNA from recombinant plasmid pFBJ-2 was able to induce morphological transformation of rat fibroblasts in tissue culture. Transfected cells contained the p55 and p39 antigens specific for cells transformed by FBJ-MSV (T. Curran and N. M. Teich, J. Virol. 42:114-122, 1982). The organization of the FBJ-MSV provirus was analyzed by restriction endonuclease mapping, and a region of nonhomology with the helper virus was delineated. Sequences specific for this region (presumably the viral fos gene) were subcloned and used as a probe to identify related sequences present in the normal genomes of cells from a variety of mammalian species (cellular fos). A single-size (3.4 kilobases long) class of RNA hybridizing to the viral fos probe was identified in FBJ-MSV-transformed cells.

Animals↗
PubMed1982

On the resident aerobic bacterial skin flora in unaffected skin of patients with atopic dermatitis and in healthy controls.

In 14 patients with atopic dermatitis the superficial bacteria from unaffected skin were extracted with the scrub method, aerobically cultured, and analysis qualitatively and quantitatively. For comparison, 12 healthy subjects served as control group. Staphylococcus aureus, as well as coagulase-negative staphylococci were significantly increased in patients with atopic dermatitis. It is assumed that special characteristics of the horny layer in atopic dermatitis favor the growth of aerobic bacteria. The qualitative biotyping and phage typing gave no support to the claim that special bacteria dominate the microbial flora of the skin of patients with atopic dermatitis.

Adult↗
PubMed1981

Single-electron transfer from NADH analogues to singlet oxygen.

Laser flash photolysis techniques have yielded rate constants for physical and reactive quenching modes of O2(1 delta g) by nicotine, nicotinamide adenine dinucleotide (oxidized and reduced forms) and the reduced forms of nicotinamide mononucleotide, nicotinamide adenine dinucleotide phosphate and nicotinamide hypoxanthine dinucleotide. In the case of the last four named compounds, kinetic spectroscopy furnished evidence for one-electron transfers to O2(1 delta g). Specifically, production of O2 was demonstrated unequivocally by reaction with 1,4-benzoquinone. Quantitative determinations revealed the extent of reactive quenching to be near 60% in each case.

Chemical Phenomena↗
PubMed1981

Protein-coding potential of mouse mammary tumor virus genome RNA as examined by in vitro translation.

The protein-coding capacity of the mouse mammary tumor virus genome has been examined by in vitro translation of genome length and polyadenylated subgenomic fragments of viral RNA. Intact genome RNA of about 35S programmed synthesis of the Pr77gag, Pr110gag and Pr160gag/pol precursors seen in infected cells in vivo. Polyadenylated RNA fragments of 18 to 28S encoded products whose tryptic peptide maps resembled those of the nonglycosylated precursor to the envelope glycoproteins, confirming the gene order 5'-gag-pol-env-3'. Translation of polyadenylated RNA fragments smaller than 18S yielded a series of related proteins whose peptide maps bore no resemblance to any of the virion structural proteins. Thus, a region of the mouse mammary tumor virus genome distal to the env gene appears to have an open reading frame sufficient to encode at least 36,000 daltons of protein as of yet unknown function.

Cell-Free System↗
PubMed1981

Microbial colonization of prosthetic devices. II. Scanning electron microscopy of naturally infected intravenous catheters.

Forty two nonselected naturally infected intravenous catheters were investigated by Scanning Electron Microscopy (SEM) and usual bacteriological methods. In many catheter samples an amorphous deposited substance could be detected by SEM investigation, mostly associated with the isolation of staphylococci, Acinetobacter calcoaceticus and Pseudomonas aeruginosa. The thickest layers of such a substance were found in catheters infected by coagulase-negative staphylococci. The bacteria seemed to be closely packed and cemented by this matrix. It's possible protective role against the defence mechanisms of the host and chemotherapeutic agents was discussed.

Bacteria↗
PubMed1981

Phage-typing of Klebsiella strains from Cologne and Wroclaw.

276 strain of Klebsiella pneumoniae and Klebsiella oxytoca were phage-typed. 126 of these strains were isolated from clinical sources in the Institute of Hygiene in Cologne and 150 came from Wrocław. The set of 19 phages used for phage-typing was chosen out of 46 Klebsiella specific bacteriophages. 80% of the isolates from Cologne were sensitive to the phages in comparison to 83% of the strains from the Wrocław region. The phage sensitivity of the German strain differed from that of the Polish strains. 28 of the 67 phage-types were seen in Cologne and 35 in Wrocław, only 6 phage-types were observed in both regions. The frequency and the spectrum of the phage-types were different, too. Phage-types denoted by the numbers 1, 17, 32, 36, 37, 59, 64 appeared to be most frequent (10 to 16 strains). No significant differences in the sensitivity to typing phages between strains of Klebsiella pneumoniae and Klebsiella oxytoca were demonstrated.

Bacteriophage Typing↗