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Biomedical subjects

A D Osborne

Publications and source records attributed to A D Osborne.

At least 19 recordsLinked to original sources
PubMed1986

The normal microflora of the female rabbit's genital tract.

Microorganisms associated with the vagina, cervix and uterus of rabbits were isolated and identified. The predominant microorganisms isolated from the vaginas and cervices were coagulase-negative staphylococci, micrococci, and nonfermentative bacilli. Coagulase-negative staphylococci were isolated frequently, but in small numbers, from the uteri. The pH of the rabbit vagina was found to be near neutrality. Our data indicate that the genital flora of female rabbits is relatively simple, regarding the number and type of microorganisms.

Animals↗
PubMed1983

Dose response relationship of Haemophilus pleuropneumoniae aerosols in pigs.

The virulence of Haemophilus pleuropneumoniae was quantitated for ten and 12 week old pigs following aerosol exposure. The volume and concentration of culture aerosolized, the estimated numbers of organisms inhaled by the pigs and the mortality rates at 72 hours postexposure were computed and used to calculate the LD50. There was correlation between the concentration of culture aerosolized, the amount of the estimated inhaled dose and the mortality rates. The ten week old pigs were apparently more susceptible to aerosols of H. pleuropneumoniae than the 12 week old pigs. The LD50 value or a multiple of it appears to be a reasonable basis for a standardized aerosol challenge of the immunity of pigs vaccinated with experimental or commercial H. pleuropneumoniae vaccines.

Aerosols↗
PubMed1983

Pulmonary clearance of Bacillus subtilis spores in pigs.

The pulmonary clearance rate of Bacillus subtilis was determined in ten pigs (23-39 kg) exposed simultaneously for 15 minutes to an aerosol generated by an ultrasonic nebulizer. Two pigs were killed at each interval of zero, two, four, eight and 12 hours and the concentrations of B. subtilis in lungs (all lobes), dorsal and ventral nasal turbinates, trachea, pharyngeal and bronchial lymph nodes were determined. The mean percent (+/- standard error) pulmonary clearance of B.subtilis was 54.2+/-11.7, 53.0+/-11.8, 77.4+/-5.2 and 88.1+/-3.7 at two, four, eight and 12 hours, respectively. The numbers of B. subtilis retained in the posterior (caudal and accessory) lobes at zero time were significantly greater than those in the anterior (cranial and middle) lobes (P<0.05). However, by 12 hours postinoculation the numbers of organisms retained in the two regions did not differ significantly (P>0.05). The mean percentage of B. subtilis retained by the turbinates, trachea, pharyngeal and bronchial lymph nodes varied between pigs at each time interval, but was usually less than that retained by the lungs. It was concluded that deposition of B. subtilis spores took place in all parts of the respiratory tract when pigs were exposed to aerosols and that the spores were progressively cleared by the normal lung.

Aerosols↗
PubMed1983

A model aerosol exposure system for induction of porcine Haemophilus pleuropneumonia.

One group of six pigs and another group of three pigs were separately exposed in a polyethylene enclosed chamber for ten minutes, respectively, to Haemophilus pleuropneumoniae serotype 1 and Bacillus subtilis aerosols generated by an ultrasonic nebulizer. Haemophilus pleuropneumoniae and B. subtilis were deposited throughout the lungs immediately following aerosol exposure. The number of H. pleuropneumoniae and B. subtilis deposited varied within and between lungs in each group. The mean numbers of both organisms deposited in the posterior (caudal and accessory) lobes were significantly greater than those in the anterior (cranial and middle) lobes (P less than 0.001). The four principals that received H. pleuropneumoniae aerosols and the two contact controls developed fatal fibrinous pneumonia which simulated that seen in natural infections. Since this exposure system consistently resulted in clinical disease it has good potential as a model for the study of pathogenesis of the disease and more specifically for the evaluation of vaccines.

Aerosols↗
PubMed1982

Secondary structure and dynamics of glucagon in solution.

A correlation between the secondary structure of glucagon determined by circular dichroism and its dynamic behaviour as obtained from picosecond fluorescence anisotropy is demonstrated. The CD data show that the percentage of alpha-helix decreases with increasing temperature, but the rotational relaxation time of the glucagon increases with temperature. These observations suggest that the protein's shape changes with temperature in such a way that its volume is larger at 38 degrees C than at 5.5 degrees C. The fluorescence anisotropy of glucagon decays biexponentially at each temperature studied and at 26 degrees C the rotation lifetimes are 1670 and 307 ps at pH 10.2 and 2147 and 517 ps at pH 2.2. It is proposed that the shorter decays are due to the restricted motion of the single tryptophan residue while rotation of the whole protein is responsible for the longer decays. The calculated rotational diffusion coefficient, Dw, of the tryptophan residue is much smaller, (ie. has a larger apparent volume) than that of a free tryptophan in solution. The hydrophobic interactions between residues Phe-22 to Leu-26 are probably responsible for the larger apparent volume in the protein compared to solution and will stabilize this part of the protein. The rotational diffusion of aggregated glucagon is also discussed.

Circular Dichroism↗
PubMed1981

An outbreak of Pseudomonas mastitis in dairy cows.

An outbreak of mastitis in a dairy herd is described in which the causative organism was Pseudomonas aeruginosa. Cases occurred either in dry cows or in animals which had very recently calved. The fact that all four quarters were involved is a very strong indication that the bacteria had been introduced in the dry cow therapy.

Animals↗
PubMed1981

An abattoir survey of the incidence of pneumonia in Saskatchewan swine and an investigation of the microbiology of affected lungs.

The lungs of 15 409 pigs, mostly from Saskatchewan, slaughtered at an abattoir were examined over a one year period. The incidence of lesions was 36.7% for "enzootic" pneumonia and 2.1% for pleurisy unassociated with pneumonia. Seasonal variations were recorded and compared with the results of similar surveys carried out in Australia, Belgium and England. Mycoplasmological examination of lungs from 347 animals was consistently negative for Mycoplasma hyopneumoniae. Pasteurella multocida was the commonest bacterial isolate, a result which agrees with those of other workers.

Animals↗
PubMed1981

Pneumonia in Saskatchewan swine: abattoir incidence of intrathoracic lesions in pigs from a herd infected with Haemophilus pleuropneumoniae and from other herds.

A 1978-79 survey of the incidence of thoracic cavity lesions at slaughter had shown that the overall incidence of pleurisy in Saskatchewan swine was low (2%). Therefore, in the summer of 1979 a comparison was made between the incidence of pleurisy in a herd of pigs chronically affected with Haemophilus pleuropneumoniae pneumonia and in animals from other herds slaughtered at the same time. The incidence of pleurisy in control pigs (3.6%) was slightly higher than in the large scale survey but in the pigs from the Haemophilus infected herd it was almost four times as great (13.3%). In the same herd the survivors of a batch of pigs which had been decimated by more severe disease showed an incidence of 32% pleurisy. The economic implications of these findings are detailed and discussed.

Animals↗
PubMed1979

Antibody studies in natural bovine cowpox.

Serological studies on cows recovered from natural cowpox indicated that Haemagglutinin-Inhibiting (HAI) antibody persisted for at least 27 weeks, and Virus Neutralizing (VN) antibody persisted for at least 98 weeks.

Animals↗
PubMed1979

Proliferative hemorrhagic enteropathy in swine: an outbreak and review of the literature.

An account is given of an acute outbreak of hemorrhagic enteric disease in 34 young adult boars of primarily Yorkshire breeding at a performance testing station in Western Canada. Two of the boars died. A diagnosis of proliferative hemorrhagic enteropathy was made on the basis of clinical signs, gross necropsy and histopathological lesions. Campylobacter-like bacteria were seen in the apical cytoplasm of epithelial cells of the ileal mucosa by Warthin-Faulkner stain on histological sections, but were not isolated on culture. Treatment with several drugs simultaneously was associated with termination of the outbreak, but the therapeutic effect was not controlled by leaving some animals untreated. Reported sequelae, such as porcine intestinal adenomatosis, were not present at necropsy or slaughter of pigs surviving the outbreak, but all were killed no longer than two months after the first case was observed. This outbreak is discussed in the context of previously reported hemorrhagic enteric conditions of pigs.

Anemia↗
PubMed1978

Treatment of experimental calf salmonellosis with amoxycillin.

Treatment of experimental Salmonella dublin infection in the calf with amoxycillin is described. In most animals a rapid response occurred when the drug was administered by the parenteral route. Results were moderately good when the oral route was used in calves fed solely on a milk replacer diet. In calves consuming hay and concentrates oral administration was much less efficient.

Administration, Oral↗
PubMed1977

Aujeszky's disease in a pack of hounds.

Aujeszky's disease occurred in a pack of harrier hounds in the south west of England and caused the death of 11 of a pack of 51 animals. The onset appeared to have followed the feeding of pig carcase material from a very large fattening unit. No evidence of clinical disease was seen in pigs in this unit, but serological evidence of earlier infection was obtained. Interesting lesions in the intestinal wall of the hounds are described.

Animals↗