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Biomedical subjects

M J Twiehaus

Publications and source records attributed to M J Twiehaus.

At least 19 recordsLinked to original sources
PubMed1976

Diarrhea in gnotobiotic calves caused by the reovirus-like agent of human infantile gastroenteritis.

Gnotobiotic newborn calves were found to be susceptible to infection with the reovirus-like agent of human infantile gastroenteritis (HRVL). Infection was based on (i) seroresponse using immunofluorescence and (ii) fecal shedding of virus particles using electron microscopy. Virus was detected in fecal samples for at least 2 to as long as 7 days after inoculation, although peak virus concentrations were observed on days 1 to 4. Diarrheal illness was observed in seven calves on second to fourth serial passage of HRVL in calves but in none of four animals studied on first passage. Diarrhea began 15 to 30.5 h (mean = 22.3 h) post-inoculation and lasted less than 24 h; three of the seven animals that developed diarrhea were also depressed or anorectic.

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↗
PubMed1973

Cell culture studies of a neonatal calf diarrhea virus.

The effects of a neonatal calf diarrhea virus on cell cultures were investigated. Bovine embryonic kidney cell cultures were the most satisfactory for production of virus. Cytoplasmic changes detected after inoculation with a high multiplicity of virus were: 1) cytoplasmic vacuoles; 2) some eosinophilic cytoplasmic inclusions; and 3) some degeneration of cells and detachment from the monolayer. Cultures stained with fluorescein-labeled antibody showed cytoplasmic fluorescence as early as four hr after infection with the maximum fluorescence at five days. No cross reactions were observed between the neonatal calf diarrhea virus and reovirus type 1 or type 3 by the fluorescent antibody technique. Plaques were small and were not produced consistently. The optimal adsorption time was one to two hr. The maximum titer was reached at 18 hr, with the cell-associated titer remaining higher than the cell-free titer until that time. An interferon was produced by cultures infected with either ultraviolet-inactivated or untreated virus.

Adsorption↗
PubMed1971

Effects of thiabendazole treatment on weight gains by Nebraska range cattle.

The results of these studies indicate that a high percentage of Nebraska range cattle are infected with gastrointestinal parasites, but at a subclinical level of infection. However, significant differences were not observed in average daily gain between thiabendazole-treated range cattle and unmedicated controls in three of four field trials. In the three trials the average improvement in daily gain in animals receiving thiabendazole once averaged .01 lb greater than untreated controls. During a 120 day grazing period this improvement would not be sufficient to pay for the wormer or cost of additional labor.

Analysis of Variance↗