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Biomedical subjects

C A Mebus

Publications and source records attributed to C A Mebus.

At least 91 records · Page 5Linked to original sources
PubMed1976

Characterization of a calf diarrheal coronavirus.

A coronavirus-like agent isolated from feces of a calf with diarrhea and attenuated by consecutive passage in a fetal bovine kidney cell line was characterized as a coronavirus. Negatively stained virions were approximately circular, had a mean diameter of 120 nm, and were covered with wide-spaced, petal-shaped projections about 20 nm long. Virions in ultrathin sections of infected cell monolayers had a mean diameter of 80 nm, lacked surface projections, and were found within cytoplasmic vesicles. Viral antigen was demonstrated by immunofluorescence microscopy to occur only in cytoplasm. Growth of the virus was not inhibited by 5-iodo-2'- deoxyuridine and actinomycin D. The virus was sensitive to ether, chloroform, deoxycholate, and heat treatment. However, thermosensitivity was stabilized in the presence of 1 M MgCl2; at pH 3, the virus was stable. Hemadsorption and hemagglutination were observed with erythrocytes of hamsters, mice, and rats but not with erythrocytes of cats, dogs, goats, sheep, cattle, horses, turkeys, chickens, guinea pigs, rabbits, geese, pigs, and man (type O). However, hemadsorption and hemagglutination were shown to be virus specific, since this could be inhibited by specific antiserum. Both infectivity and hemagglutinating activity were maximal at a particle density of 1.18 g/ml by sucrose density gradient centrifugation, indicating that hemagglutinin was part of the virion.

Animals↗
PubMed1976

Immune response to orally administered calf reovirus-like agent and coronavirus vaccine.

Twenty 6-to 7-hour-old gnotobiotic calves inoculated orally with attenuated calf diarrhea reovirus-like agent and challenge-inoculated with virulent virus 48-72 h post-inoculation (PI) remained clinically normal during the post-vaccination observation period; one developed mild diarrhea after challenge inoculation. Four non-vaccinated challenge control calves developed severe diarrhea. Twenty 6-to 7-hour-old gnotobiotic calves inoculated orally with attenuated calf diarrhea coronavirus and challenge inoculated with virulent virus 96 h later remained clinically normal during the post-vaccination and post-challenge observation period. Four non-vaccinated challenge control calves developed severe diarrhea and 2 of these died. Five-foot long isolated loops prepared in the lower ileum (Thiry-Vella loop) of newborn colostrum-deprived calves were inoculated with attenuated coronavirus. Daily loop washings were cultured for virus and tested for neutralizing antibody. Peak viral titers of 10(6.5) to 10(7) occurred 3-4 days PI and descended rapidly to 0 between 6 and 8 days PI. Neutralizing antibody was first detected in the washings 6-8 days PI and reached a titer of 128-256 7 to 9 days PI. Loop immunoglobulin separated by gel filtration and identified by immunodiffusion were primarily IgM and IgA. Initial resistance to virulent viral infection is thought to be due to an interference phenomenon, with later resistance due to local antibody.

Administration, Oral↗
PubMed1975

New complement-fixation test for the human reovirus-like agent of infantile gastroenteritis. Nebraska calf diarrhea virus used as antigen.

A complement-fixation (C.F.) test for the human reovirus-like agent of infantile gastroenteritis has been developed using the serologically related Nebraska calf diarrhoea virus (N.C.D.V.) as antigen. Most infants and children who shed the agent in stools and/or who demonstrated serological (C.F.) evidence of infection with a reovirus-like-particle-positive human stool-filtrate C.F. antigen also demonstrated serological evidence of infection when a concentrated N.C.D.V. preparation was employed AS C.F. antigen. The N.C.D.V., which was previously shown to be related to the human reovirus-like agent, was found to be related antigenically to the epizootic diarrhoea of infant mice (E.D.I.M.) virus also. Studies on the prevalence of C.F. antibody in sera from infants and young children revealed a pattern of rapid acquisition of antibody to both the human reovirus-like agent and the N.C.D.V. as over 80 percent of these individuals possessed antibody to each agent by 36 months of age. A strong positive association was found in the results obtained with the two antigens. The ready availability of cell-culture grown N.C.D.V., and its ability to serve as a "substitute" C.F. antigen for the human reovirus-like agent, should enable the serodiagnosis of many cases of disease due to the human agent and facilitate seroepidemiological studies of such infections. In addition, the observation that a large proportion of individuals infected with the human reovirus-like agent develop serological evidence of infection not only to the human agent but to the calf agent as well may have important implications in the immunoprophylaxis of disease caused by the human reovirus-like agent.

Animals↗
PubMed1975

Scanning electron, light, and transmission electron microscopy of intestine of gnotobiotic calf.

Adjacent areas of upper, middle, and lower parts of the small intestine and spiral colon from a 48-hour-old gnotobiotic calf were compared by scanning electron microscopy (SEM), light microscopy (LM), and transmission electron microscopy (TEM). As visualized by all 3 methods, small intestinal histologic features, except for apical location of villous epithelial cell nuclei in sections of upper and middle parts of small intestine, were similar to those described for other species. The colonic surface visualized by SEM was composed of flattened ridges separated by furrows into which opened the crypts of Lieberkühn. The epithelial surfaces of the ridges and the furrows had an extensive microvillous covering and scattered goblet cell openings.

Animals↗
PubMed1975

Scanning electron, light, and immunofluorescent microscopy of intestine of gnotobiotic calf infected with calf diarrheal coronavirus.

Intestinal lesions in 2 gnotobiotic calves given (oral inoculation) calf diarrheal coronavirus were studied by scanning electron, light, and immunofluorescent microscopy. The calves were euthanatized at 34 and 73 hours after the onset of diarrhea. Lesions in the small intestine were similar to those reported in animals affected with transmissible gastroenteritis of swine. Small intestinal villi were shortened, some adjacent villi were fused, and villous epithelium was composed of low cuboidal to squamous cells. In the ansa spiralis coli, there were atrophy of the colonic ridges and marked differences in length and spacing of the microvilli on individual epithelial cells.

Animals↗
PubMed1975

Recovery of transmissible gastroenteritis virus from chronically infected experimental pigs.

Transmissible gastroenteritis (TGE) virus was reisolated from pulmonary and intestinal tissues from 6 of 9 chronically infected experimental pigs (principals) necropsied 30 to 104 days after inoculation. Tissue homogenates (lung and small intestine) from the principals were prepared and inoculated into 3- to 5-day-old gnotobiotic pigs. The virus reisolated from the tissue homogenates produced a milder disease on 1st passage and a more severe disease on 2nd passage. The chronically infected experimental pigs (principals) developed serum-neutralization titers to TGE of 1:30 to 1:525. There appeared to be no relationship between serum titers and reisolation of TGE virus from the 9 principals. The persistence of virus in lung or intestine to 104 days indicates the recovered (or carrier) pig may be considered the primary source of TGE virus infection.

Animals↗