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Biomedical subjects

R C Fader

Publications and source records attributed to R C Fader.

26 records · Page 2Linked to original sources
PubMed1982

Immunoglobulin A and secretory immunoglobulin A antibodies to purified type 1 Klebsiella pneumoniae pili in human colostrum.

Immunoglobulin A antibodies with binding specificity for purified Klebsiella pneumoniae type 1 pili were detected by an enzyme-linked immunosorbent assay in 20 of 21 human samples (95%). The concentrations of secretory immunoglobulin A antibody in colostrum directed against the pili were calculated by comparison of experimental enzyme-linked immunosorbent assay values with values obtained from known secretory immunoglobulin A concentrations. The presence of antibodies to K. pneumoniae type 1 pili was confirmed by double diffusion-gel studies with selected specimens of colostrum. This study shows that in the majority of human colostral samples examined, secretory immunoglobulin A antibodies with specificity for K. pneumoniae type 1 pili can be commonly found in variable, but frequently high, concentrations.

Adolescent↗
PubMed1981

Evidence for a bladder cell glycolipid receptor for Escherichia coli and the effect of neuraminic acid and colominic acid on adherence.

The rat bladder epithelial cell receptors involved in mannose-sensitive adherence of Escherichia coli strains were studied. Sodium metaperiodate and lipase pretreatment of epithelial cells significantly reduced bacterial adherence to cells whereas trypsin and phospholipase C had a marginal or insignificant effect on adherence. Neuraminidase and colominic acid significantly increased adherence, whereas N-acetylneuraminic acid significantly reduced adherence. These data suggest that the rat bladder epithelial cell receptors involved in mannose-sensitive adherence are glycolipids. In addition, the data suggested that sialic acid on bladder epithelial cells acts as a nonspecific inhibitor of adherence, whereas colominic acid, a component of some E. coli K1 capsules, may act as a promoter of adherence.

Animals↗
PubMed1981

Environmental alteration and two distinct mechanisms of E. coli adherence to bladder epithelial cells.

We used an in vitro model to investigate Escherichia coli attachment to transitional epithelial cells obtained from bladders of female rats. Adhesive abilities and sensitivity to mannose inhibition differed among the isolates for both epithelial cells and erythrocytes. Adherence of some strains could be modulated by bacterial washes and growth media. Variations in adhesiveness were related to bacterial piliation as determined by transmission electron microscopy. With two strains, mannose inhibition of adherence to epithelial cells was dose-related; however, with a maximal inhibitory dose, adherence was reduced by approximately 80 per cent even when the bacteria-to-epithelial cell ratio was varied. These studies show that adhesiveness and piliation of certain adhesive E. coli strains are either reduced or enhanced by environmental alterations. We conclude that E. coli strains adhere to epithelial cells by at least two distinct mechanisms and that a single isolate may utilize both mechanisms. The more efficient process is pili-mediated and inhibited by mannose whereas undetermined surface components mediate the less efficient but mannose-resistant mechanism.

Animals↗
PubMed1980

Effect of piliation on Klebsiella pneumoniae infection in rat bladders.

The possible role of pili in the pathogenesis of urinary tract infection caused by Klebsiella pneumoniae was investigated in a rat model of cystitis by utilizing piliated- and nonpiliated-phase organisms derived from a single parent strain. Bladder surfaces were examined for evidence of infection by scanning electron microscopy. In animals infected with piliated-phase organisms, foci of infection were evident in the majority of bladders examined. Rat bladders associated with nonpiliated-phase bacteria showed little evidence of infection. The ability of methyl-D-mannoside, a known inhibitor of pilus-mediated adherence to mammalian cells, to protect the bladder surface from colonization was also tested. The results showed a significant decrease in the ability of piliated-phase K. pneumoniae to establish infection in bladders. These observations suggest that pili may play an integral role in the ability of K. pneumoniae to cause urinary tract infections by mediating the attachment of the bacteria to the uroepithelial surface.

Animals↗
PubMed1979

Evidence for pili-mediated adherence of Klebsiella pneumoniae to rat bladder epithelial cells in vitro.

The possible role of pili in the pathogenesis of urinary tract infections caused by Klebsiella pneumoniae was studied in an in vitro mixture of a phosphate-buffered saline suspension of rat bladder epithelial cells and phosphate-buffered saline-washed K. pneumoniae. Nonpiliated and piliated populations derived from a single K. pneumoniae strain were obtained by controlling the total time of growth in broth medium. The piliated phase demonstrated a significant increase in adherence when compared to the nonpiliated phase. Incubation of the bacteria and epithelial cell mixture at 4 and 37 degrees C resulted in no differences in adherence; optimal adherence occurred at pH 5. Pretreatment of the bacteria with enzymes to destroy the pili resulted in a decrease in adherence, as did killing the bacteria by various means before adherence testing. Pretreatment of the epithelial cells with certain saccharides inhibited bacterial adherence. Finally, a 96% decrease in adherence was observed after coincubation of bacteria and epithelial cells with papain-treated antipili antibodies. Thus, it appears that pili on the surface of K. pneumoniae mediate attachment of the bacteria to rat bladder epithelial cells.

Adhesiveness↗
PubMedDate not supplied

Effect of preexisting inhalation injury on response to bacteremia in sheep.

Inhalation injury increases the likelihood of sepsis. We tested the hypothesis that preexisting inhalation injury would diminish bacterial clearance across the pulmonary vasculature and induce greater hemodynamic response. Live Pseudomonas aeruginosa were infused centrally for one hour in three groups of awake sheep. Inh + Ps (n = 10), with a seven to 10-day-old inhalation injury; Ps-LOW (n = 8) both received 10(7) Ps/min; and Ps-HI (n = 9) received 5 x 10(7) Ps/min. for one hour. Pulmonary hypertension was more severe in Ps-HI and Inh + Ps. A hyperdynamic response with high cardiac index and low mean arterial pressure developed in Inh + Ps and Ps-HI from six to 18 hr, while Ps-LOW, only the cardiac index was elevated at six to eight hr. The Inh + Ps and Ps-LOW groups had equivalent pulmonary artery and aortic bacterial levels, while Ps-HI had levels approximately five times higher. All groups removed bacteria efficiently in the lungs. However, preexistent inhalation injury exaggerated the pulmonary and systemic hemodynamic response.

Animals↗
PubMedDate not supplied

Effect of thermal injury and immunosuppression on the dissemination of Candida albicans from the mouse gastrointestinal tract.

Candida albicans dissemination through the gastrointestinal tract was examined in mice given a thermal injury, immunosuppressive therapy, or both. After gastrointestinal tract colonization with C. albicans, mice were initially subjected to a 20% total body surface area, full-thickness, dorsal scald burn. Only one mouse in the burned group (5%) had evidence of C. albicans in the liver at the time the mice were killed. No dissemination was observed in sham-burned animals. When mice were immunosuppressed with cyclophosphamide, an increased incidence of gastrointestinal tract dissemination was noted in burned (31%) and sham-burned (23%) mice; however, only 3 days after burn was there a significant difference in dissemination between burned and sham-burned mice (p less than 0.02). This corresponded to the day of severest neutropenia in response to cyclophosphamide treatment. The results of the study indicate that C. albicans can disseminate from the gastrointestinal tract in response to thermal injury, but a significant suppression of the immune response must occur for the event to be commonplace.

Animals↗