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Biomedical subjects

R G Thomson

Publications and source records attributed to R G Thomson.

At least 91 records · Page 5Linked to original sources
PubMed1971

Urinary delta amino levulinic acid (ALA) in the cow, dog and cat.

The level of delta amino levulinic acid (ALA) was determined in the urine of normal cows and dogs, and in the urine of dogs, cows and cats with a variety of diseases. ALA was measured in the urine of two steers and two dogs experimentally poisoned with lead. Experimental lead poisoning was followed by increased excretion of ALA in the urine. Higher levels of ALA were present in the urine of sick dogs and cats than in the urine of sick cows.

Amino Acid Metabolism, Inborn Errors↗
PubMed1971

Regional histological variations of the nasal mucosa of cattle.

Aspects of the histology of the nasal mucosa of calves from four to six months of age have been described. The functional significance of the type of epithelium, its thickness, the degree of neutrophil invasion, and its relationship to the numbers of Pasteurella haemolytica in the nasal cavity have been discussed. In addition, the arrangement and depth of glands in the lamina propria and the presence of lymph follicles have been described.

Analysis of Variance↗
PubMed1971

Pasteurella haemolytica of cattle: serotype, production of beta-galactosidase and antibacterial sensitivity.

Two hundred and three isolates of Pasteurella haemolytica from cattle were studied. They originated from the nasal cavity of cattle in housed herds; the nasal cavity and pneumonic lungs of experimental feedlot calves and from pneumonic bovine lungs submitted for bacteriological diagnosis.To determine whether a single characteristic or combination of characteristics might be a feature of isolates collected from animals with pneumonic pasteurellosis (Shipping Fever), the following tests were made. Cultures were serotyped by indirect haemagglutination; the ability to produce beta-galactosidase was examined in the ortho-nitrophenyl-beta-D-galactopyranoside (ONPG) test and antibacterial sensitivity tests were done. None of these factors could be directly related to the role of P. haemolytica in "Shipping Fever".

Animals↗
PubMed1970

Preliminary observations on the effect of specific immunity on nasal bacterial flora.

This investigation has shown that Pasteurella hemolytica could actively colonize the nasal cavity of calves in the presence of indirect hemagglutinating IHA antibody against that particular strain. It was not determined if the level of nasal IHA antibody to Past. hemolytica had an effect on colonization of the nasal passage by Past. hemolytica. Specific immunity to Past. hemolytica would appear to be important in respiratory disease induced by this organism.

Animals↗
PubMed1970

Influence of immunization procedures on upper respiratory tract immunity in cattle.

Aspects of respiratory tract immunity have been investigated in the bovine species. Using Past. hemolytica type I as the antigen for this model the relationship of nasal and serum antibody production to the route of vaccination and type of vaccine was investigated in a series of 15 dairy calves from two to four months of age. Experimental results indicated that an aerosol vaccination with live Past. hemolytica resulted in a significant nasal antibody response while parenterally vaccinated gave calves with equivalent serum titers had no significant nasal antibody response.

Aerosols↗
PubMed1969

Pneumonic pasteurellosis of cattle: microbiology and immunology.

Pasteurellosis was investigated under natural conditions by comparing bacterial and viral nasal flora and levels of bacterial and viral antibody in sera and nasal secretions between animals sick with the disease and those that remained well. The animals were classified sick or well on the basis of the levels of body temperature and plasma fibrinogen. The most significant feature of the bacterial flora was the higher frequency of isolation and the numbers of Past. hemolytica in the nasal flora in the first two weeks after shipment. As indicated by the number of animals with serum antibody to PI-3 virus, infection with this virus was active in both sick and well animals, and serologically, the incidence of infection was higher in animals that remained well. Nasal antibody to PI-3 virus was slightly lower in incidence than serum antibody. Examination of untreated fatal cases and animals killed during the experiment suggests that in some animals there may be a relationship between the high numbers of a bacterial species in the nasal passage and infection by that organism in the lung.

Animals↗
PubMed1969

Nasal bacterial flora of calves in healthy and in pneumonia-prone herds.

An enclosed swab assembly was employed in a survey of 790 samples of nasal mucus collected from calves in 12 herds. It was possible to classify the nasal bacterial flora of calves in three components, basal, supplementary and transient. The potential pathogens, P. multocia, and P.hemolytica, together with micrococci, saprophytic Neisseria and a Streptococcus composed the basal flora and were judged to be widely distributed in the cattle population.A special bacteriological-statistical formula was employed to quantitatively classify the populations of several bacterial species. Enzootic pneumonia of calves was not found to be associated with a characteristic nasal bacterial flora; in contrast, cases of bacterial pneumonia in a well-managed "pool" herd of young bulls were regularly associated with the isolation of P. hemolytica from the nasal secretion. Pasteurella species were capable of dominating the flora for periods of several days at a time in what was judged to be a state of active colonization of the nasal muscosa with shedding of the organisms in large numbers. This state of active colonization did not fore-tell the likelihood of the development of pneumonia in affected calves; periodic suppression of P. hemolytica was observed in closely studied calves.

Animals↗
PubMed1969

Experimental adenovirus infection in calves.

Twenty-four dairy calves ranging in age from six to 15 weeks were divided so that 10 were inoculated with bovine adenovirus serotype 1 (BA-1), eight were inoculated with bovine adenovirus serotype 3 (BA-3), and six were inoculated with control tissue culture and fluids.Post-inoculation serum samples from most of the calves presented evidence of adenovirus infection, but none of the animals exhibited signs of respiratory or enteric disease. Histopathological examination of lung tissue was not considered to be specific for adenovirus pneumonia, but was characterized by peribronchial cuffing and slight aspiration pneumonia. BA-1 was not isolated from any of the inoculated calves, and BA-3 was only recovered from the feces of two animals. Reasons for the discrepancy between these results and those of other workers are considered, and the etiology of peribronchial cuffing is briefly discussed.

Adenoviridae↗
PubMed1968

Pathogenicity of vibrio coli for swine. I. Experimental infection of gnotobiotic pigs with vibrio coli.

Fifteen gnotobiotic pigs varying in age from three to eight weeks were exposed to 23 strains of V. coli isolated from swine with clinical and/or pathological signs of swine dysentery and also from clinically healthy pigs. Clinical or pathological signs of swine dysentery were not produced, although the organism was readly established in the sedimentary tract. Culture of feces, alimentary tract and environment revealed V. coli in large numbers, but no bacterial growth was obtained from other organs. The histopathology and serology are discussed.

Animals↗