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Biomedical subjects

G F Webster

Publications and source records attributed to G F Webster.

At least 73 records · Page 4Linked to original sources
PubMed1981

Activation of the alternative pathway of complement in human serum by Propionibacterium acnes (Corynebacterium parvum) cell fractions.

Activation of the alternative pathway of complement is known to be initiated by bacterial structures. We have fractionated Propionibacterium acnes cells, purified various cell fractions, and tested their complement-activating ability in human serum chelated with ethyleneglycol bis-(beta-aminoethylether)-N,N1-tetraacetic acid. The majority of complement-activating activity was localized in the wall fraction. This activity was resistant to lipid extraction, protease, RNAse, DNAse and lysozyme treatment. NaIO4, formamide, and hot (but not cold) trichloroacetic acid (TCA) extraction ablated the complement-activating capacity of cell walls. Compounds removed by extraction failed to consume significant hemolytic activity against antibody-coated sheep erythrocytes (EA). Addition of TCA-extracted soluble material to cell wall suspensions resulted in an inhibition of hemolytic consumption by the cell wall. These results indicate that, in P. acnes, complement-activating molecules are located in the cell wall and are carbohydrate in nature. Peptidoglycan, lipid, protein, and nucleic acid do not appear to contribute to the cell wall's ability to activate complement.

Carbohydrates↗
PubMed1981

Inhibition of the classical and alternative pathways of human and guinea pig complement by pyran copolymer.

The ability of pyran copolymer to interact with the classical and alternative pathways of complement was assessed in human and C4-deficient guinea pig serum. Pyran induced a dose-dependent inhibition of hemolytic activity in both serum systems. Immuno-electrophoretic analysis of pyran-treated human serum revealed that C3 was not cleaved. Factor B was altered into a more anionic mobility which was not similar to biologically cleaved Ba or Bb fragments. Pyran-treated serum was unable to lyse antibody-coated erythrocytes (EA or EA coated with C1 and C4 and EA coated with C1, C4 and C2. Pretreatment of serum with ethylenediaminetetraacetic acid did not prevent inhibition of hemolytic activity by pyran. Cobra venom factor did not cleave C3 in the presence of pyran. These data indicate that pyran does not activate complement by standard mechanisms but does inhibit one or more of its components.

Animals↗
PubMed1980

Characterization of serum-independent polymorphonuclear leukocyte chemotactic factors produced by Propionibacterium acnes.

The size and production of polymorphonuclear leukocyte (PMN) chemotactic factors by Propionibacterium acnes has been studied. All eight strains of P. acnes which were tested liberated PMN chemotactic factors in their growth culture media. The factor(s) produced by one strain, 6919, were studied in greater depth. The PMN response was proportional to the dose of culture supernatant and chemotactic activity increased with the duration of P. acnes culture. The neutrophil migration towards culture supernatants was chemotactic, with a slight stimulation of random migration by 72-h supernatants. The size of the chemotactic molecules was studied through dialysis, ultrafiltration, and Sephadex G-25 chromatography of 72-h supernatants. Low-molecular-weight chemotactic factors were found to be predominant by each method of size determination.

Chemotactic Factors↗
PubMed1980

Polymorphonuclear leukocyte lysosomal release in response to Propionibacterium acnes in vitro and its enhancement by sera from inflammatory acne patients.

Propionibacterium acnes cells were tested for the ability to trigger lysosomal hydrolase release from human polymorphonuclear leukocytes. Representative strains of P. acnes serotype I and II failed to stimulate lysosomal release in the absence of serum. P. acnes growth culture supernatants failed to trigger release under any test condition. Addition of fresh or heat-inactivated human serum resulted in lysosomal hydrolase release directly proportional to the number of P. acnes/PMN. Pooled sera from acne patients, with a high anti-P. acnes titer stimulated release to P. acnes. Preabsorption of this reagent with P. acnes cells reduced the anti-P. acnes titer and produced 93.37 +/- 11.49% inhibition of lysosomal enzyme release compared to unabsorbed anti-serum. Electron microscopy indicated that P. acnes was readily phagocytosed by PMNs when fresh or heated serum was present.

Acne Vulgaris↗
PubMed1980

Headspace analysis of volatile metabolites of Pseudomonas aeruginosa and related species by gas chromatography-mass spectrometry.

Gas chromatographic-mass spectrometric analysis of headspace volatiles was performed on cultures of 11 strains of Pseudomonas aeruginosa and 1 strain each of Pseudomonas cepacia, Pseudomonas putida, Pseudomonas putrefaciens, Pseudomonas fluorescens, and Pseudomonas maltophilia. All strains of Pseudomonas aeruginosa produced a distinctive series of odd-carbon methyl ketones, particularly 2-nonanone and 2-undecanone, and 2-aminoacetophenone. The other strains failed to produce 2-aminoacetophenone. Two sulfur compounds, dimethyldisulfide and dimethyltrisulfide, were present in strains of P. aeruginosa and in variable amounts in other species. Butanol, 2-butanone, 1-undecene, and isopentanol were also detected in P. aeruginosa cultures.

Alcohols↗
PubMed1980

Regional variations in density of cutaneous propionibacteria: correlation of Propionibacterium acnes populations with sebaceous secretion.

Cutaneous Propionibacterium acnes populations were quantitatively measured in 33 young adults and compared with the rate and composition of sebum secretion in nine skin regions. Bacteriological and lipid analyses were performed on the forehead, cheek, anterior chest, abdomen, lower back, volar forearm, upper inner arm, thigh, and calf. P. acnes populations in these sites correlated significantly with the total amount of lipid produced (r = 0.77) as well as with di- and triglycerides (r = 0.68), squalene and wax esters (r = 0.72), cholesterol and cholesterol esters (r = 0.67), and free fatty acids (r = 0.67).

Adolescent↗
PubMed1980

Serologic analysis of the extractable carbohydrate antigens of Pityrosporum ovale.

Antigens soluble in hot trichloracetic acid from eighteen strains of Pityrosporum ovale were studied using rabbit antiserum to American Type Culture Collection strains 24027, 12078, and 14521. These strains were found to share two antigens, both of which were present in cells of Pityrosporum orbiculare and one of which was present in cells of Pityrosporum pachydermatis, Pityrosporum canus, Candida albicans and Rhodotorula rubrum.

Antigens, Fungal↗
PubMed1979

A method for the assay of inflammatory mediators in follicular casts.

A method is presented whereby inflammatory mediators may be detected and quantified in individual follicular casts. Lysozyme, lactoferrin, IgG, IgM, C3 and material reacting with antiserum to polymorphonuclear leukocytes (PMN) were assayed by functional and immunologic methods. By these techniques, lysozyme, IgG and anti-PMN reactive material were detected in clinically uninflamed follicular casts from acne subjects.

Acne Vulgaris↗
PubMed1979

Characteristic gamma-lactone odor production of the genus Pityrosporum.

Mass spectrometric-gas chromatographic analysis of culture headspaces revealed that members of the genous Pityrosporum produce volatile gamma-lactones during growth on lipid-containing media. Representative members of other yeast genera found on humans failed to produce these compounds. Addition of lecithin, oleic acids, triolein, or human sebum to the culture media stimulated gamma-lactone production by Pityrosporum species. All yeasts tested produced isopentanol and phenylethanol. Production of gamma-lactones may serve as a valuable characteristic in the identification of organisms of the genus Pityrosporum.

Culture Media↗
PubMed1979

Complement activation in acne vulgaris: consumption of complement by comedones.

Comedones, the contents of acne lesions, were shown to consume scomplement hemolytic activity in normal serum. This consumption was stimulated by the addition of serum from patients with inflammatory acne. Absorption of acne serum with Propionibacterium acnes cells removed all stimulating activity. Immunoelectrophoretic analysis of serum incubated with comedones revealed the conversion of C3 and factor B in normal serum. The addition of acne serum resulted in cleavage of C4. In serum treated with ethylene glycol-bis(beta-aminoethyl ether)-N,N'-tetraacetic acid, only C3 and factor B were converted. This indicates that comedones may activate complement by either the classical or the alternative pathway. It is suggested that P. acnes cells in comedonal material are responsible for the complement activation.

Acne Vulgaris↗
PubMed1978

Regional variations of cutaneous propionibacteria.

Propionibacterium acnes, P. avidum, and P. granulosum were quantitatively measured in 50 young adults. The scalp, forehead, external auditory canal, alae nasi, anterior nares, groin, rectum, and antecubital and popliteal fossa were sampled. These represent various cutaneous microenvironments, differing in moisture, density of sweat, sebaceous glands, and extent of anaerobiosis. These studies show that the propionibacteria are ubiquitous on the skin, with P. acnes predominant in both prevalence and population, especially in areas rich in sebum. P. granulosum recovery paralled that of P. acnes, but the density was significantly lower. P. avidum was found mainly in moist areas and the retum, suggesting an intestinal reservoir.

Adolescent↗
PubMed1978

Complement activation in acne vulgaris: in vitro studies with Propionibacterium acnes and Propionibacterium granulosum.

To better define the role of bacteria in inflammatory acne vulgaris, we have investigated the ability of four strains of Propionibacterium acnes and three strains of Propionibacterium granulosum to activate complement. Complement activation was assayed by incubating normal human serum with varying concentrations of each strain and measuring residual total hemolytic complement activity. When serum was tested unaltered, P. acnes strains were approximately threefold more potent than an equal weight of P. granulosum in consuming complement, which could reflect classical and/or alternative pathway activation. All strains also consumed complement in serum chelated with ethyleneglycol-bis (beta-aminoethyl ether)-N,N'-tetraacetic acid, which selectively assays alternative pathway activation. Incubation of unaltered serum with both P. acnes and P. granulosum resulted in immunoelectrophoretic conversion of C4, C3, and factor B of the alternative pathway. Incubation of chelated serum resulted in conversion of C3 and factor B. These data taken together suggest that both species can activate complement through either pathway. Serum incubated with P. acnes was chemotactic for polymorphonuclear leukocytes, and this chemotactic activity was largely C5 dependent as shown by antibody inhibition. It is suggested that complement activation may occur in vivo in acne, and the inflammatory response may be contributed to by the generation of C5-dependent chemotactic factors.

Acne Vulgaris↗
PubMed1978

Use of bacteriophage typing to distinguish Propionibacterium acne types I and II.

Strains of serotypes I and II of Propionibacterium were compared for phage sensitivity. The two serotypes could be distinguished by using a typing set consisting of 16 bacteriophages at concentrations that demonstrated selective lysis of serotype I or II bacterial strains. Seven phage types were found; three were composed exclusively of serotype I, and four were exclusively composed of serotype II organisms. Generally, serotype I strains were more sensitive to phage lysis than were serotype II strains. No correlation was found between phage type and site of isolation.

Bacterial Infections↗