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R D Glock

Publications and source records attributed to R D Glock.

At least 37 records · Page 2Linked to original sources
PubMed1982

Applications of peroxidase-antiperoxidase staining technique for detection of transmissible gastroenteritis virus in pigs.

The peroxidase-antiperoxidase (PAP) staining technique was used for the detection of transmissible gastroenteritis virus (TGEV) in small intestines of TGEV-infected 8-week-old pigs and in infected McClurkin pig testicle cells by means of light microscopy. The specific-positive reaction was characterized by the presence of many brown granules of various sizes in the cytoplasm of infected cells. Nonspecific granules caused by endogenous peroxidases in the cytoplasm of eosinophils stained by PAP were darker, larger, more round, and more uniform in size than were specific granules. Acetone fixation was superior to fixation with periodate-lysine-paraformaldehyde or 10% formalin. Our results indicate that the PAP staining technique is a sensitive, specific technique for detection of TGEV in the small intestines of pigs.

Animals↗
PubMed1982

Changes in gut-associated lymphoid tissues of the small intestine of eight-week-old pigs infected with transmissible gastroenteritis virus.

The responses of the interepithelial lymphocytes (IEL) and aggregated lymph nodules (ALN; Peyer's patches) of the small intestines of 8-week-old pigs to transmissible gastroenteritis virus (TGEV) infection were characterized at 12, 18, and 24 hours after pigs were inoculated. There was no significant difference in numbers of IEL between control and TGEV-infected pigs at 12 and 18 hours. However, in pigs examined at 24 hours, there was a significant decrease in the number of IEL in the duodenum and cranial portion of the jejunum and an increase of IEL numbers in the nuclear level of the intestinal epithelium. Number and distribution were unchanged in the middle portion of the jejunum and the ileum. Microscopic changes in TGEV-infected pigs included microulceration of the dome epithelium (DE) over the ALN, especially in the cranial portion of the intestine, and villous atrophy in the entire length of the small intestine. Generally, TGEV was found by means of peroxidase-antiperoxidase staining in areas where microscopic lesions occurred. Electron microscopy revealed that M cells and ordinary microvillus-covered epithelial cells in the DE embraced one or more lymphocytes, and formed a specialized cell complex or DE complex. Most of the lymphocytes in the DE complex possessed many organelles indicative of an active cell state. The TGEV was found between microvilli, in the cytoplasmic vesicles of M cells and microvillus-covered epithelial cells in the DE, and in the cytoplasm of macrophages and lymphocytes and some degenerated cells of unidentified origin in the domes of the ALN. The virus was also commonly found in cytoplasmic vesicles of macrophages and degenerated cells in the intestinal lumen near the base of the dome of the ALN.

Animals↗
PubMed1982

Naturally occurring porcine proliferative enteritis: pathologic and bacteriologic findings.

The lesions of porcine proliferative enteritis were studied by light and electron microscopic techniques in feeder pigs, fattening hogs, bred gilts, sows, and boars. The characteristic microscopic feature common to all age groups was proliferation of immature crypt epithelial cells, primarily in the ileum and the distal part of the jejunum. Similar changes were also observed in the midjejunum, cecum, and colon of a new swine. The earliest detectable microscopic lesion was focal proliferation of crypt epithelial cells with accompanying inflammation of the lamina propria and leukocytic exudate within affected crypt lumina. Lesions progressed to diffuse crypt cell proliferation, elongation of crypts, and loss of villi. Immature epithelial cells contained variable numbers of intracytoplasmic, nonmembrane-bound, curved organisms resembling Campylobacter sp bacteria. Similar organisms were within phagolysosomes of macrophages in the lamina propria and within the cytoplasm of crypt epithelial cells undergoing mitosis. Campylobacter sputorum subsp mucosalis was isolated from the ileal mucosa in 30 of 58 swine.

Animals↗
PubMed1982

Porcine proliferative enteritis: experimentally induced disease in cesarean-derived colostrum-deprived pigs.

The hypotheses that porcine proliferative enteritis is an infectious disease and that Campylobacter sputorum subsp mucosalis (CSM) is involved in the development of this disease were experimentally tested. Three experiments were conducted with 10-week-old, cesarean-derived colostrum-deprived pigs. Of 22 pigs given homogenized mucosal scrapings (crude inocula) intragastrically, 15 had gross and/or microscopic lesions of proliferative enteritis. Of 10 pigs inoculated with cultures of both CSM and Salmonella cholerae-suis, 2 had evidence of proliferative enteritis. The 4 pigs treated with S cholerae suis only had diffuse fibrinous gastroenteritis without evidence of mucosal proliferation. Proliferative enteritis was produced in 1 of 5 pigs inoculated with pure cultures of CSM. Proliferative lesions in the intestine were characterized by the proliferation of immature crypt epithelial cells. Affected cells contained variable numbers of curved, intracytoplasmic Campylobacter sp organisms. The CSM organism was isolated from the intestinal mucosa of 8 pigs treated with either crude inocula or cultures of CSM.

Animals↗
PubMed1981

Production of lesions in gnotobiotic mice by inoculation with Treponema hyodysenteriae.

Treponema hyodysenteriae was established in the ceca of gnotobiotic mice in the absence of other organisms. Superficial mucosal lesions characteristic of swine dysentery were present in the ceca of mice inoculated with T. hyodysenteriae in combination with viable Bacteroides vulgatus. Deep crypt necrosis was detected in the ceca of mice inoculated with T. hyodysenteriae alone.

Animals↗
PubMed1980

Differentiation of Treponema hyodysenteriae from T innocens by enteropathogenicity testing in the CF1 mouse.

Fourteen isolates of Treponema hyodysenteriae and 11 isolates of T innocens from eight different countries were evaluated in the CF1 strain female mouse for virulence. Mice were fasted for 24 hours and inoculated intragastrically with 1 ml of culture for two consecutive days. Mice were killed and necropsied at 12 to 15 days after inoculation. Caecitis was detected in mice from each of the groups receiving T hyodysenteriae (67 per cent) but not in mice receiving T innocens or sterile broth. Lesions consisted of hyperaemia, mucosal oedema, catarrhal inflammation and occasional haemorrhage. These studies suggest that the CF1 mouse may be an inexpensive in vivo means of differentiating T hyodysenteriae from T innocens.

Animals↗
PubMed1980

Pathophysiology of swine dysentery: colonic transport and permeability studies.

Net transport of electrolytes and water, unidirectional Na+ and Cl- fluxes, and mucosal permeability were examined in isolated colonic loops of control pigs and pigs infected with Treponema hyodysenteriae. Results indicated that all net ion and water absorption from the colon was abolished in infected pigs. This abolition of net absorption was almost exclusively the result of a decrease in the lumen-to-blood fluxes of Na+ and Cl-; the blood to lumen fluxes and mucosal permeability were essentially unaffected. The results indicated that the diarrhea observed in these pigs was a consequence of colonic absorptive failure alone. Neither an active nor a passive secretory process could explain the fluid losses under the conditions of these experiments.

Animals↗
PubMed1979

Pathogenic synergism between Treponema hyodysenteriae and other selected anaerobes in gnotobiotic pigs.

Gnotobiotic pigs were orally exposed to various anaerobes at 6 to 9 days of age and similarly inoculated with Treponema hyodysenteriae B204 3 to 6 days later. Watery diarrhea and fecal excretion of large quantities of mucus and some fibrin clots were observed 4 to 20 days after inoculation with B204 if other anaerobes were present. Colonic lesions characteristic of swine dysentery were observed when B204 was present with Fusobacterium necrophorum, three strains of Bacteroides vulgatus, a Clostridium species, and Listeria denitrificans individually and when some of these microbes were present in various combinations, but not when B204 was present alone. These results are consistent with the conclusion that T. hyodysenteriae is the primary pathogen in the etiology of swine dysentery and that the presence of one or more other anaerobes is a prerequisite for expression of pathogenicity of T. hyodysenteriae. This prerequisite can be met by a variety of anaerobes.

Anaerobiosis↗
PubMed1978

Isolation of Treponema hyodysenteriae from sources other than swine.

Fecal samples were collected from animals and environments on 3 swine farms and cultured for Treponema hyodysenteriae. Each farm was a farrow-to-finish operation and, at the time of sampling, swine dysentery was enzootic among 8- to 22-week-old pigs. Pathogenic T hyodysenteriae was isolated from pigs on all 3 farms. On farm A, nonpathogenic T hyodysenteriae was isolated from a sample of lagoon water. On farm B, pathogenic T hyodysenteriae was isolated from a waste-holding pit. On farm C, a dog was observed to be eating feces of pigs that had swine dysentery. The dog was diarrheic and a fecal sample yielded a pathogenic isolant of T hyodysenteriae. Further isolation attempts were unsuccessful after the dog was removed from the infected premises. Isolation of pathogenic and nonpathogenic organisms from waste-holding systems emphasizes the need for cultural techniques in detecting pathogenic T hyodysenteriae.

Animals↗
PubMed1978

Swine dysentery: studies of gnotobiotic pigs inoculated with Treponema hyodysenteriae, Bacteroides vulgatus, and Fusobacterium necrophorum.

Transmission experiments were carried out in gnotobiotic pigs to determine whether lesions typical of swine dysentery could be produced by oral inoculation of Treponema hyodysenteriae in combination with Bacteroides vulgatus or Fusobacterium necrophorum, or both. Each of the organisms had been isolated from swine with early lesions of the disease. Lesions were not found in 6 pigs inoculated with T hyodysenteriae alone, in 4 pigs given F necrophorum and T hyodysenteriae, or in 4 pigs given B vulgatus and F necrophorum. Lesions typical of swine dysentery developed in 8 pigs given B vulgatus, F necrophorum, and T hyodysenteriae as well as in 3 of 4 pigs given B vulgatus and T hyodysenteriae. In both of these groups, the inoculated bacteria were recovered from the colon, and T hyodysenteriae was demonstrated in the colonic crypts, epithelium, and lamina propria. The pathogenicity of the T hyodysenteriae was shown by the development of characteristic signs and lesions of swine dysentery in 12 of 14 naturally farrowed pigs inoculated with T hyodysenteriae alone.

Animals↗
PubMed1978

Experimental infection with Treponema hyodysenteriae in guinea pigs.

Outbred and inbred (Hartley strain) guinea pigs (GP) were inoculated intragastrically with pathogenic and nonpathogenic Treponema hyodysenteriae. GP 3 to 16 weeks old received T. hyodysenteriae after a fasting period of 36 to 72 h. Infected GP with pathogenic T. hyodysenteriae developed a diarrheal and/or depressive condition, with mucus but not blood in the feces. Of 88 GP, 40 had gross lesions resembling those of swine dysentery. Lesions were limited mainly to the large intestine. TP used as controls or inoculated with nonpathogenic T. hyodysenteriae did not develop these lesions in the large intestine. These studies suggest that the GP may be used as an animal model for swine dysentery.

Animals↗
PubMed1978

Parenteral immunization of pigs against infection with Treponema hyodysenteriae.

Six intravenous injections of formalin-inactivated Treponema hyodysenteriae were given to 8 specific-pathogen-free pigs at 6-day intervals. The 8 vaccinated and 8 control pigs were challenged intragastrically with pure cultures of T hyodysenteriae 7 and 8 days after the last intravenous injection. Clinical signs of swine dysentery were observed in all 8 control pigs, but was observed in only 1 of the immunized pigs. Three control pigs died. These findings suggest that parenteral immunization with T hyodysenteriae provided a marked degree of protection against subsequent intragastric challenge exposure with the homologous isolate of T hyodysenteriae.

Animals↗
PubMed1978

Enteropathogenicity testing of Treponema hyodysenteriae in ligated colonic loops of swine.

Multiple, ligated loops of swine colon were used as an in vivo model in which to test enteropathogenicity of isolates of Treponema hyodysenteriae. Gross and microscopic lesions observed in 21 of 22 colonic loops in pigs killed 48 to 72 hours after inoculation with isolates known to be enteropathogenic were characteristic of swine dysentery. These lesions were not observed in 12 loops exposed to uninoculated media or in 12 loops inoculated with nonpathogenic isolates of T hyodysenteriae. The swine-loop technique provides a relatively rapid, economical, reliable model in which to test enteropathogenicity of T hyodysenteriae isolates.

Animals↗