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Biomedical subjects

J C Wilt

Publications and source records attributed to J C Wilt.

At least 19 recordsLinked to original sources
PubMed1984

Detection of Clostridium difficile toxin with McCoy cell monolayers and cell suspensions and comparison with HeLa cell assay.

McCoy cell monolayers were compared with HeLa cell monolayers for the detection of Clostridium difficile toxin in 301 stool samples. Tests were positive (greater than or equal to 1/100 dilution) in 83 and 81 specimens tested with McCoy and HeLa cell monolayers, respectively. McCoy cell suspensions were compared with HeLa cell monolayers in 532 stool filtrates. Overall, 90 positive specimens were within one dilution and 432 filtrates were negative with either test, giving a correlation coefficient of r = 0.98. McCoy cell monolayers or suspensions may be a satisfactory substitute for the detection of C. difficile toxin in clinical specimens.

Bacterial Proteins↗
PubMed1983

Prevalence of antibodies to Chlamydia trachomatis in healthy population groups in Manitoba.

The prevalence of antibodies to Chlamydia trachomatis was determined in 1877 serum samples from healthy population groups of Caucasians, native Indians and recent Vietnamese immigrants in Manitoba. Testing was done with a commercially available immunofluorescence kit containing C. trachomatis antigen. The presence of antibodies was age-related; a progressive increase in prevalence was observed in children aged 1 to 15 years, and the overall prevalence was higher in female Caucasian blood donors and female Vietnamese immigrants than in males in both groups. However, there was no sex-related difference in prevalence among the subjects undergoing premarital testing or among the native Indians. Antibodies were more prevalent (p less than 0.001) in pregnant than in nonpregnant women matched for race and age, and a relatively high prevalence (66.6%) was found in the cord serum of newborns. The overall prevalence rate of antibodies in all Manitobans was 48.8% (44.9% in men, 55.9% in women and 35.3% in children.

Adolescent↗
PubMed1981

C. psittaci 6 BC soluble hemagglutinin: factors influencing the red cell receptor sites.

Human blood-group A, B and O erythrocytes did not possess receptor sites for either crude or ether-ethanol extracted chlamydial soluble hemagglutinin. Sensitive chicken erythrocytes were agglutinated to higher titres by ether-ethanol extracted than by crude chlamydial hemagglutinin. Studies indicated that trypsin-, chymotrypsin-, neuramanidase-sensitive receptor sites were not essential for binding of ether-ethanol extracted chlamydial hemagglutinin; neither were beta-glucuronidase- nor periodate-sensitive receptor sites essential. Since soluble chlamydial hemagglutinin consists of components of host cells and that of chlamydiae purification of hemagglutinin from chlamydiae is required in future studies.

ABO Blood-Group System↗
PubMed1981

Chlamydial hemagglutinin: interaction of ether-ethanol extracted fraction with sensitive erythrocytes.

Chlamydial particles and soluble hemagglutinin were separated by differential centrifugation from the supernatant of L-cells and the allantoic fluid of chick embryo infected with C. psittaci 6BC and C. trachomatis TW-3. Concentrated hemagglutinin was fractionated with ether-ethanol; specimens were compared using sensitive erythrocytes of adult white Leghorn chickens. The ether-ethanol extract had a 40- to 80-fold higher hemagglutinin titer than the crude hemagglutinin or the ether-ethanol insoluble fraction. The extracted hemagglutinin also showed a higher complement-fixing activity than the other two fractions. Extracted hemagglutinin was stable for 3 months at 4 degrees and --70 degrees C when sonicated immediately before hemagglutinin; it agglutinated to a similar titer at 37 degrees, 25 degrees and 4 degrees C, showing the reaction to be temperature independent; it agglutinated to a similar titer within a pH range of 7.0 to 8.0 McIlvaine citrate buffer-saline solution and Dulbecco's phosphate buffer solution without Ca++ and Mg++ at pH 7.0 were both suitable for hemagglutinin-titration. Hemagglutination failed to take place in non-electrolyte solutions.

Allantois↗
PubMed1980

Host influence on the density of chlamydiae in Renografin gradients.

Egg-grown and L cell-grown C. psittaci 6BC strains formed two bands when centrifuged through preformed Renografin gradients. No additional bands were observed by extending the time of centrifugation. Particles present in the bands which were collected from the Renografin gradients were examined by electron microscopy. Purified elementary bodies from both egg- and L cell-grown sources were located in a lower, minor bind; egg-derived elementary bodies showed a higher density (p < 0.01) than elementary bodies derived from L cells. Particles present in the major, upper band of both egg- and L cell-derived strains had similar densities and contained mixed populations of elementary bodies and polymorphic reticulate bodies.

Animals↗
PubMed1980

Infectivity of penicillin-induced Chlamydia psittaci forms for cell cultures from the chorioallantoic membrane of chick embryos.

L-cells were infected at high multiplicity with meningopneumonitis organsims (MP) and incubated in medium with penicillin (200 units/ml) and without the drug. At intervals up to 36 hours cells were removed and L-cell associated chlamydial infectivity was determined for cell cultures from the chorioallantoic membrane (CAM) of chick embryos which were treated before inoculation with Diethylaminoethyl (DEAE)-Dextran. In control L-cells, the infectivity decreased at 8 hours and reached it lowest level 16 hours after infection. In penicillin-treated L-cells in contrast, infectivity remained at low levels from 2 and up to 36 hours after infection. At 16 hours after infection about 90% of both penicillin-treated and nontreated L-cells contained single or multiple Giemsa-stained intracytoplasmic inclusions which in both series contained almost exclusively reticulate bodies (RB) by electron microscopy. RB from 16 hour infected penicillin-treated and non-treated L-cells were partially freed from cell debris and their infectivity (ID50) for CAM-culture cells (TC) was assayed 3 times. Penicillin-induced RB had TCID50 of 10(4.0)/ml compared to control RB of 10(4.5)/ml. The TCID50 of the original MP strain for CAM-culture cells was 10(8.0)/ml. Penicillin-induced RB and control RB from 16 hour L-cell samples were frozen and thawed 3 times and titrated in CAM cells; the TCID50 of both series dropped to 10(1.0)/ml while the TCID50 of the original MP inoculum after freezing and thawing 3 times was 10(7.0)/ml.

Animals↗
PubMed1978

Antimicrobial susceptibility of Haemophilus ducreyi.

The susceptibility of 19 isolates of Haemophilus ducreyi from a recent chancroid outbreak and four reference strains was determined in vitro to 13 antimicrobial agents. The rabbit intradermal test for virulence was positive for all of the local isolates, but not for the reference strains. The "nonvirulent" reference strains were inhibited by lower minimum inhibitory concentrations (MICs) of most agents tested. For the virulent isolates, the range of MICs (in micrograms per milliliter) of the following were: of vancomycin, 8 to 128; of polymyxin, 32 to 128; of cloxacillin, 32 to 64; of tetracycline, 0.5 to 32; of cephalothin, 4 to 8; of doxycycline, 0.25 to 8; and of kanamycin, 1 to 8. Three strains were resistant to penicillin and ampicillin (MIC >/= 128 mug/ml), and these three strains produced beta-lactamase. The remainder were susceptible to 4 mug/ml. All strains were susceptible to rifampin (MIC </= 1 mug/ml), chloramphenicol (MIC </= 4 mug/ml), sulfisoxazole (MIC </= 8 mug/ml), and nalidixic acid (MIC </= 8 mug/ml). These susceptibilities of H. ducreyi indicate several antimicrobial agents that may be effective for chancroid treatment and support the use of vancomycin in a selective medium for the culture of chancroid genital ulcers.

Animals↗
PubMed1978

Comparison of specimen collection and laboratory techniques for isolation of Haemophilus ducreyi.

Sixteen patients with clinical chancroid were studied prospectively; different culture media and sampling techniques from genital lesions were evaluated. Technique A was aspiration of a saline wash from the ulcer which was pooled and inoculated into rabbit blood, rabbit blood + vancomycin (5 microgram/ml), and semisolid chocolate agar + vancomycin (3 microgram/ml). Each primary culture medium was subcultured to chocolate agar with 1% IsoVitaleX (CA), CA with vancomycin (3 microgram/ml) plus polymyxin (7.5 microgram/ml; CA + vp). Technique B was the use of a cotton swab, plated directly on CA, CA + v, and CA + vp. Nine strains of Haemophilus ducreyi were obtained. Technique A yielded seven strains, whereas technique B yielded eight strains; with each technique, five strains were isolated only after use of selective antibiotic media. CA + v medium yielded the largest number of isolates. Direct inoculation by swab to CA + v from chancroidal ulcers is effective as an isolation technique for growth of H. ducreyi.

Bacteriological Techniques↗
PubMed1978

Determination of the hemin requirement of Haemophilus ducreyi: evaluation of the porphyrin test and media used in the satellite growth test.

Gonococcal (GC) agar supplemented with glucose and glutamine was found to be superior to Eugonagar and Trypticase soy agar in demonstrating the hemin requirement of 23 strains of Haemophilus ducreyi by the satellite growth test. The porphyrin test confirmed the requirement for exogenous hematin. With the agar dilution technique, using supplemented GC agar, the hemin concentration required to initiate growth was 10 microgram/ml, and the optimal hemin concentration to produce growth equivalent to that on chocolate agar was between 200 and 500 microgram/ml. On GC agar with added glucose and glutamine, the lowest hemin concentration impregnated in paper disks able to initiate satellite growth was 50 microgram/ml. The hemin requirements of these H. ducreyi were much higher than that reported for other Haemophilus species.

Bacteriological Techniques↗
PubMed1977

Sucrose density differences of Chlamydia psittaci 6BC in relation to its host.

Previous studies on Chlamydia psittaci 6BC propagated in different hosts have shown differences in cytotoxicity but no differences in the ultrastructure of the individual particles. It is shown here that the 6BC strain derived from yolk sac of infected chick embryo sedimented in sucrose gradients at lower densities than the 6BC strain derived from L-cells. Host-related modifications of lipid concentrations of the 6BC strains have been previously documented by others. It is thought that the phenomenon of host-induced modifications of physical properties of the agent might provide a new approach to the study of chlamydial pathogenicity.

Animals↗
PubMed1976

Autoradiography of [3H]thymidine-labeled Chlamydia psittaci 6BC in mononuclear phagocytes.

Incorporation of tritiated [3H]thymidine by Chlamydia psittaci 6BC was achieved by growing the parasites in chick embryo yolk sac explants which were exposed to exogenous labeled thymidine. These labeled, purified chlamydiae were next observed by autoradiography within mouse peritoneal macrophages. The number of silver grains remained constant in the cytoplasm of macrophages throughout the developmental cycle of the parasite. The proliferation of labeled chlamydiae in macrophages was confirmed by Giemsa staining and immunofluorescence. Chlamydiae have never been successfully labeled with thymidine in earlier studies when assayed in cultured mammalian fibroblasts. It is suggested that a critical factor in the successful incorporation thymidine in chlamydiae may be the host-parasite system used.

Animals↗
PubMed1976

Alterations in the ultrastructure of Chlamydia psittaci 6BC harvested from the allantoic fluid of chick embryos.

The allantoic fluid of chick embryos infected with Chlamydia psittaci is routinely used as a source of material for the study of the chemical and biological properties of the chlamydiae. We have examined pellets recovered from this allantoic fluid by low- and high-speed centrifugation, as well as high-speed pellets which had been stored at -70 degrees C, and we find that all of the pleomorphic forms of the chlamydiae are present in these materials. The reticulate bodies and large intermediate bodies are always seen to be morphologically damaged in that their cell envelopes are modified and in that they are distended and occasionally 'leaky.' No morphological evidence of damage was seen in small intermediate bodies or in elementary bodies in any of the materials which were examined. Thus the chlamydial population recovered from the allantoic fluid of infected chick embryos has been modified by selective damage to the least-condensed particles. We propose that the release of lysosomal enzymes from the host cell may coincide with the release of the chlamydia and that these enzymes may be responsible for this selective damage.

Allantois↗
PubMed1976

Ultrastructural studies of the nucleoids of the pleomorphic forms of Chlamydia psittaci 6BC: a comparison with bacteria.

The nucleoids of the various pleomorphic forms of Chlamydia psittaci have been examined by direct observation of infected cells and by observations on isolated particles. The fixation and staining methods used were the same as those routinely used for the examination of bacteria to facilitate the comparison of chlamydial fine structure with that of bacteria. The nucleoids of reticulate bodies were composed of fine fibrils which extended throughout these particles. The nucleoids of intermediate bodies are characterized by an electron-dense mass with which the fibrous elements are associated in a structurally coherent manner. As condensation of the intermediate bodies proceeds, the electron-dense mass becomes eccentrically located and the fibers form a distinct radiating structure. Large elementary bodies have a few fibers associated with their condensed electron-dense nucleoids but the more condensed mature elementary bodies have a very discrete and homogeneous electron-dense nucleoid which is separated from the cytoplasmic elements of these particles by a very distinct electron-transparent space. These highly condensed elementary body nucleoids are usually ovoid, but may be elongated or irregular, and a small number of these structures react very strongly with ruthenium red. While the nucleoid structure of reticulate bodies resembles that of the bacterial cell, both the condensation process and the nucleoid morphologies which result from it in intermediate and elementary bodies have no parallels among the bacteria. Thus we conclude that major differences in nucleoid organization exist between the chlamydia and the bacteria.

Bacteria↗
PubMed1976

Differences in physicochemical and antigenic properties of chlamydial strains.

Antigenic analysis of Chlamydia psittaci, C. trachomatis, and Lymphogranuloma venereum (LGV) revealed basic physicochemical differences among the three chlamydial strains. These were manifested in structural, isoelectric points, absorption spectra, and in the characteristics of the chromophobe-containing proteins. The effective period of sonication for C. psittaci and C. trachomatis is around 60 min during which the linkages most susceptible to external sonication forces were broken, releasing all attainable cellular components. Denaturation studies demonstrated that less than 50% of protein content of C. psittaci was denatured after 1 h of sonication, only 5% in the case of C. trachomatis. The protein and carbohydrate content of the most reactive fractions in macrophage-spreading inhibition test were different for LGV and C. trachomatis. The structural differences appear to determine the antigenic properties observed among the chlamydial strains as well as the specificity and probably the mechanisms (s) of cellular immune reactivity to Chlamydiae. This in turn may explain the failure of chlamydial vaccines, prepared from stock strains, to protect immunized children against 'wild' chlamydial strains.

Antigens, Bacterial↗
PubMed1976

Phagocytic and chlamydiae-inhibiting activities of stimulated and nonstimulated periotneal mouse macrophages.

Phagocytic and chamydiacidal properties of nonstimulated and stimulated mouse mononuclear cells for two Chlamydia psittaci 6BC strains were investigated. It was determined that macrophages kept in monolayer culture (i.e. stimulated phagocytes) developed much more efficient chlamydiacidal ability than did cells kept in suspension directly after harvest (i.e. nonstimulated phagocytes). A thousandfold decrease of chlamydial infectivity was observed 60 min after induction of phagocytosis in stimulated macrophages, irrespective of the strain offered. In contrast, the infectivity of both chlamydial strains remained essentially unchanged up to 1 h after phagcoytosis by nonstimulated phagocytes. Electron-microscopic examination indicated that chlamydiae were disintegrated within phagolysosomes of stimulated phagocytes within minutes after phagocytosis, although ultrastructurally altered chlamydiae not enclosed in vacuoles were also observed in the cytoplasm of several mononuclear phagocytes at different times after phagocytosis.

Animals↗
PubMed1975

Lysosomes and the "toxicity" of Rickettsias. VI. In vivo response of mouse peritoneal phagocytes to L-cell-grown Chlamydia psittaci 6BC strain.

The L-cell-grown 6BC strain of C. psittaci inoculated intraperitoneally in mice induced an injurious effect on mononuclear phagocytes and their lysosomes; the influx of polymorphonuclear phagocytes (PMN's) increased markedly and the PMN's showed karyorrhexis and lysis. Cytochemical methods failed to detect chlamydial forms in peritoneal fluids from day 1 and up to 6 days after inoculation of mice. Chlamydial infectivity was not detected in either the cell-bound or the cell-free fractions of peritoneal cells from 6 h up to 6 days after inoculation of mice. In contrast, after infection of mice with the egg-grown 6BC strain, readily identifiable multiplication of the parasites occurred from 4 days after inoculation of mice; the lysosomes of macrophages were refractory to egg-grown 6CB particles that were initially ingested and the macrophages were nonspecifically "activated." Some of these "transformed" into large epitheloid cells containing numerous chlamydial inclusions in the cytoplasm. That lysosomes of "professional phagocytes" play a role in the "toxic" effect of virulent chlamydiae in the intact host is discussed.

Animals↗