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R Freter

Publications and source records attributed to R Freter.

42 records · Page 3Linked to original sources
PubMed1970

Mechanism of Action of Intestinal Antibody in Experimental Cholera II. Antibody-Mediated Antibacterial Reaction at the Mucosal Surface.

Earlier studies have shown that intestinal antibody (coproantibody) decreases the adsorption of vibrios to the intestinal wall of rabbits. The mechanism underlying this phenomenon was studied by means of an in vitro model in which vibrios were grown on slices of rabbit ileum in a moist chamber. Antibody prevented the adsorption of vibrios onto such slices in the same manner as it did in vivo. Studies of the in vitro growth rate of vibrios on slices of ileum indicated an antibody-dependent antibacterial mechanism on the mucosal surface. This mechanism appeared to require the presence of viable mucosal cells, as it was not present when filter paper was substituted for the tissue slices and it could not be demonstrated in fresh scrapings from the intestinal mucosa. Antigen-antibody mixtures were added to the surface of slices of rabbit ileum or were introduced into the lumen of intestinal loops. Presence of these mixtures did not inhibit the antibody-dependent antibacterial mechanism on the mucosa in either the in vivo or the in vitro system. The amount of antigen-antibody mixture used in vivo was at least 12 times that required to neutralize the complement released by homogenization from an entire intestinal loop. The results obtained support the hypothesis that coproantibody protects by decreasing the adsorption of vibrios on the intestinal mucosa. The mechanism responsible appears to be an antibacterial effect on the mucosal surface which requires antibody plus some additional factor(s) supplied by viable mucosal cells. The postulated factor does not appear to be complement.

Journal Article↗
PubMed1969

Isolation of anaerobic bacteria from human gingiva and mouse cecum by means of a simplified glove box procedure.

An anaerobic glove box constructed of clear flexible vinyl plastic is described. It is sufficiently inexpensive and simple in operation to be used not only in research but also in a clinical laboratory by technicians without special training. Conventional bacteriological techniques may be used inside the glove box for culturing and transferring anaerobic bacteria. The box may be heated to 37 C and thus serve as an anaerobic incubator as well, permitting inspection of cultures at any time. Media may be prepared and agar plates may be poured on the laboratory bench in the conventional manner. An overlay of trace amounts of palladium black catalyst over plated agar media reduces the medium to an oxidation-reduction (O-R) potential of - 300 mv within 2 days after introduction into the glove box. In spite of its greater simplicity, the system matched or excelled the roll tube method with respect to all parameters tested, including O-R potential obtainable in the media, O(2) concentration in the gas phase, and efficiency in isolating anaerobic bacteria from the mouse cecum. Comparative studies indicate that the conventional anaerobic jar method was inadequate for the isolation of strict anaerobes from human gingival specimens and from the mouse cecum. This was due to the exposure of specimens and media to air during plating on the open laboratory bench. Anaerobic jars were adequate for maintaining the proper conditions for growth of anaerobic bacteria once these had been established in the glove box.

Animals↗
PubMedDate not supplied

Models for studying the role of bacterial attachment in virulence and pathogenesis.

Simple in vitro tests for bacterial adhesion can indeed identify the various adhesive mechanisms of bacteria on an immunologic, physiochemical, biochemical, and genetic basis. Difficulties in interpretation arise, however, when attempts are made to relate the presence of a given adhesion to the colonizing ability or virulence of a bacterium. The reasons for this confusion are threefold: (1) there is more than one basic mechanism by which bacteria may associate with mucosae; (2) numerous intervening reactions in the mucosal microenvironment modify the various steps leading to association; and (3) mucosal association may sometimes be detrimental to a bacterium. Bacterial association with the mucosa, therefore, is determined by the final equilibrium established as a consequence of various synergistic and antagonistic reactions. An understanding of such a complex, interdependent system of reactions cannot be gained solely by studying each of its component parts in isolation. More complex models, such as those developed in experimental animals, are therefore required, and the relationship between adhesion and colonization must be explored within the conceptual framework employed by ecologists.

Adhesiveness↗