Radiographic detection of thoracic lesions in adult cows: a retrospective study of 42 cases (1995-2002)

Medical records of 42 cows that underwent both thoracic radiographic and postmortem examinations within a period of 7 days were reviewed to develop an evaluation grid to interpret bovine thoracic radiographs and to determine the sensitivity and the specificity of thoracic radiographs for detection of thoracic lesions, based on postmortem examination. Most cows (64%) had clinical signs of respiratory disease, whereas 19% showed signs of cardiac problems. The sensitivity and specificity of radiographs for identifying cows with thoracic lesions were 94% and 50%, respectively. In this study, with a prevalence of thoracic lesions of 86%, the positive- and negative-predictive values were 92% and 57%, respectively. This study provides an evaluation grid that allows standardization of the reading of bovine thoracic radiographs and the identification of most thoracic lesions. Bovine thoracic radiographs are useful in detecting thoracic lesions in cows.     

Bat Rabies in Ontario

Rabies has been diagnosed for the first time in the bat population of Ontario. In the course of a study involving 72 bats from 24 counties of the province, five big brown bats (E. fuscus) were found to be infected with rabies through the mouse inoculation test. At the present time, it does not look as if bats have been connected with the epizootic of sylvatic rabies in Ontario.

La rage est apparue pour la première fois chez les chauves-souris en Ontario. Au cours d'une étude qui a porté sur 72 de ces animaux provenant de 24 comtés de la province, l'inoculation d'animaux de laboratoire a permis confirmer la présence de la maladie chez cinq grosses chauves-souris brunes (E. fuscus). A date, il ne semble toutefois pas que les chauves-souris soient impliquées dans l'épizootie de rage sylvatique qui sévit en Orntario.

     

The Use of Fluorescent Antibody Staining in the Diagnosis of Rabies

Brain material from 750 domestic and wild animals submitted to this laboratory for rabies diagnosis was studied by the following three methods: a) microscopic examination of Williams'' stained impressions, b) mouse inoculation test, and c) microscopic examination of impressions stained with fluorescein-tagged antibodies. The purpose of this investigation was to compare the sensitivity of the fluorescent antibody technique with that of two classical methods, when applied to the routine diagnosis of rabies. From the results obtained by one or the other method of study, 175 specimens were diagnosed as positive. Of these, only 58 (33 per cent) were detected by the examination of Williams'' stained impressions. On the other hand, two rabid cases were missed by the mouse inoculation test, and four by the fluorescent antibody technique. Without being completely reliable, the last two methods proved to be almost equally sensitive and much more so than the examination of Williams'' stained impressions.     

Engineering nutritious proteins: improvement of stability in the designer protein MB-1 via introduction of disulfide bridges.

Protein design is currently used for the creation of new proteins with desirable traits. In this laboratory the focus has been on the synthesis of proteins with high essential amino acid content having potential applications in animal nutrition. One of the limitations faced in this endeavor is achieving stable proteins despite a highly biased amino acid content. Reported here are the synthesis and characterization of two disulfide-bridged mutants derived from the MB-1 designer protein. Both mutants outperformed their parent protein MB-1 with their bridge formed, as shown by circular dichroism, size exclusion chromatography, thermal denaturation, and proteolytic degradation experiments. When the disulfide bridges were cleaved, the mutants' behavior changed: the mutants significantly unfolded, suggesting that the introduction of Cys residues was deleterious to MB-1-folding. In an attempt to compensate for the mutations used, a Tyr62-Trp mutation was performed, leading to an increase in bulk and hydrophobicity in the core. The Trp-containing disulfide-bridged mutants did not behave as well as the original MB-1Trp, suggesting that position 62 might not be adequate for a compensatory mutation.