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Biomedical subjects

J Greenfield

Publications and source records attributed to J Greenfield.

At least 37 records · Page 2Linked to original sources

Comparison of pressure differential procedures for dipping turkey hatching-eggs in gentamicin solution.

Studies have shown that antibiotics introduced into hatching eggs can destroy certain egg-borne bacterial pathogens. An investigation was made to determine an effective procedure to introduce gentamicin solutions into turkey eggs. The findings showed that a pressure differential (PD) method using a reduced pressure of 38 cm. (15 inches) Hg for 15 minutes followed by an absorption period of 15 minutes at atmospheric pressure was an effective method which did not cause excessive egg cracking nor adversely effect hatchability. In excess of two times more fluid was absorbed using a PD method compared to an established temperature differential procedure. For maximum absorption, eggs should be washed at collection time and stored for a period of up to two weeks prior to dipping.

Animals↗

Porcine Hemophilus parahemolyticus pneumonia in Saskatchewan. II. Bacteriological and experimental studies.

The incidence of porcine pleuropneumonia caused by Hemophilus parahemolyticus has shown a marked increase in recent years in some countries. Isolation of a strain distinct from European serotypes was made from a natural outbreak of the disease in pigs in Saskatchewan. Experimentally infected pigs did not develop clinical signs but pathologic-anatomic studies of lungs revealed the presence of necrotizing fibrinous pneumonia with intense proliferation of mesenchymal tissue elements. Similar extensive fibroblastic activity had been found to be a typical feature in the natural infection. It is speculated that the Saskatchewan strain may have invasive patterns different from European serotypes.

Animals↗

Porcine Hemophilus parahemolyticus pneumonia in Saskatchewan. I. Natural occurrence and findings.

An outbreak of fibrinous pleuropneumonia was observed in October 1971 in Saskatchewan on a farm of 900 feeder pigs. Morbidity and mortality were low. Pathologic-anatomic findings included fibrinous pleuritis, pulmonary vascular thrombosis and necrotizing fibrinous pneumonia. Hemophilus parahemolyticus was isolated from the lungs of affected animals. In addition pulmonary lesions were found which suggested an adenovirus infection. It was speculated that the viral infection possibly predisposed the pigs to the Hemophilus infection. The H. parahemolyticus isolate was sensitive to common antibiotics.

Animals↗

Isolation of Escherichia coli O157 from pigs with colibacillosis in Canada and the United States.

Cultures of Escherichia coli isolated from colibacillosis in pigs in Canada and the U.S.A. and previously identified as unclassified E. coli OX36 were found to belong to a new E. coli O group 157. Strains of E. coli V145, GIRI, C308 and V17 which had a weak relationship to E. coli O116 also were found to belong to O157. The increased incidence of E. coli O157 in colibacillosis of swine stresses the inclusion of this O group among those enteropathogenic for swine.

Agglutination Tests↗

Comparison of the rates of motility of Salmonella with those of other enteric bacteria.

Comparison of the rates of motility through a semisolid medium of 16 common Salmonella sp., 14 Escherichia coli serotypes, 4 Arizona strains, 2 Escherichia freundii (Citrobacter) isolates, 2 Proteus sp., and 2 Pseudomonas sp. revealed the following. (i) Very closely related bacteria could demonstrate markedly different rates of progression. (ii) All of the salmonellae tested advanced faster than the Proteus and Pseudomonas test cultures but some Salmonella sp., notably S. choleraesuis and S. typhi, progressed relatively slowly compared to many other test cultures. (iii) The mean rate of motility for the fastest 14 Salmonella sp. (1.49 cm/hr) was not statistically greater than the mean value for the 14 E. coli serotypes (1.31 cm/hr) at the 1% level of significance. Selective motility procedures may not be a reliable means of isolating all Salmonella sp. from materials contaminated with other bacteria.

Agar↗