Biomedical subjects
A J Hardy
Publications and source records attributed to A J Hardy.
Immunization of calves against salmonellosis.
Fifty-six normal colostrum-fed Holstein-Friesian and Holstein-Friesian X Angus crossbred calves ranging in age from 3 to 9 weeks were divided into 4 vaccinated groups and 1 nonvaccinated (control) group. Group I consisted of 10 calves vaccinated 2 or 3 times subcutaneously with formalin-killed Salmonella dublin-S typhimurium bacterin with added adjuvant. Group II consisted of 4 calves vaccinated orally with formalin-killed S typhimurium daily for 21 days. Group III consisted of 17 calves given colostrum from dams which had been vaccinated twice subcutaneously with a formalin-killed S dublin-S typhimurium bacterin with added adjuvant. Group IV consisted of 8 calves orally given small doses of live virulent S typhimurium twice. Seventeen calves served as nonvaccinated controls. One to 2 weeks after the final vaccine dose (or at 3-weeks of age for group III), all calves were orally challenge exposed with virulent S typhimurium. Oral challenge dose levels ranged from 1.5 X 10(9) viable organisms to 1.5 X 10(11) viable organisms. Mortality following oral challenge exposure was 11 of 17 controls, 6 of 10 group I calves (ns), 2 of 4 group II calves (ns), 11 of 17 group III calves (ns), and 1 of 8 group IV calves (p = 0.001). Twenty calves, 4 from group I, 8 from group III, and 8 from the control group, given 1.5 X 10(11) challenge organisms (the largest challenge, inoculum) died, whereas only 1 of 6 calves in group IV given this dose died. Group II calves were not given the 1.5 X 10(11) challenge dose. Under the conditions of this experiment, bacterins given parenterally or orally to calves or given parenterally to the dams of calves did not decrease morbidity and mortality, whereas small numbers of live organisms given orally to calves were effective in lessening morbidity and mortality following oral challenge exposure with virulent S typhimurium.
Bovine salmonellosis: experimental production and characterization of the disease in calves, using oral challenge with Salmonella typhimurium.
A highly virulent strain of Salmonella tyhimurium was given orally to produce disease experimentally in 21 normal colostrum-fed calves 3 to 9 weeks old. The challenge inoculum varied from 10(4) to 10(11) organisms. The disease was characterized by fever, depressed attitude, and decreased appetite. Many calves given larger challenge dose levels also had diarrheic feces containing mucus, fibrin, and blood. Fecal cultures were positive for salmonella. Septicemia occurred in some calves (9 of 15 calves cultured were positive). Eleven calves died and 10 calves survived challenge exposure. Survival was inversely related to the size of the challenge inoculum and directly related (although to a lesser degree) to age of the calf. White blood cell total and differential counts were variable. Both neutropenia and neutrophilia were observed. Plasma proteins decreased markedly in calves with diarrhea, probably indicating fecal protein loss. Fibrinogen increased during the acute stages of diarrhea.
Equine salmonellosis: experimental production of four syndromes.
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Prevalence and epizootiology of equine salmonellosis.
Feces from 1,451 horses entering a veterinary hospital over a 13-month period were cultured for salmonella. A total of 46 horses (3.2%) yielded 1 or more salmonella-positive fecal cultures. Twenty horses were found to be excreting salmonella in the feces on admission, and 5 of these later had severe diarrhea associated with enteric salmonellosis. Abdominal surgery and other severe stresses were associated with all cases of severe enteric salmonellosis. Serotypes of salmonella isolated included Salmonella agona (15), S anatum (14), S typhimurium (7), S typhimurium var copenhagen (4), S infantis (2), S montevideo (1), S meleagridis (1), S drypool (1), and an unnamed Salmonella serotype (1). Seven deaths were attributed to 4 serotypes (S typhimurium, 3; S anatum, 2; S typhimurium var copenhagen, 1; and S montevideo, 1). A marked seasonal incidence is isolations was found with isolations highest in later summer to early fall and lowest in the spring. It was also found that horses can shed salmonella intermittently, and a minimal of 5 consecutive negative fecal cultures is recommended before considering a horse not to be infected with salmonella.
Valine requirement of the growing kitten.
The valine requirement of the kitten was studied using a crossover design with two groups of three weanling kittens. The kittens were fed a semipurified diet containing only free amino acids as a source of nitrogen containing 0.0%, 0.6%, or 1.8% valine. The mean +/- SE of the linear components of growth (g/day) of the six kittens were respectively:-13.8 +/- 1.7, 17.3 +/- 4.8, and 15.3 +/- 2.6. Corresponding food intakes were 26.0 +/- 3.9, 50.4 +/- 2.5, and 44.0 +/- 1.5. Nitrogen balance was positive with the same amount retained for the two valine-containing diets while nitrogen balance was negative for the kittens fed the valine-free diet. Plasms valine dropped markedly when the dietary valine was decreased from 1.8% to 0.6% (363 +/- 59 versus 66 +/- 13 nmole/ml), and was further decreased (33 +/- 13) when the valine-free diet was fed. It does not appear that the valine requirement of the kitten exceeds 0.6% of a diet containing 25% fat. These results support the hypothesis that the high protein requirement of the kitten is not a result of a high requirement for all the essential amino acids, but a result of a high "nitrogen" requirement.
Analysis of the ribosomes engaged in the synthesis of the outer membrane proteins of Escherichia coli.
The messenger RNAs for the outer membrane proteins in E. coli are more stable than the bulk of the messenger RNA s (Hirashima et al., 1973). Polysomes, enriched in those containing stable mRNAs have been isolated following rifampicin treatment and have been shown to contain quantitatively the same complement of ribosomal protein as normal polysomes. There is one exception: ribosomal protein S1 is present in larger amounts in the polysomes containing stable messengers. However, there are grounds for believing this finding to be an artifact. It is concluded that the differences between outer membrane protein synthesis and bulk protein synthesis are not due to a difference in the ribosomes.
The Brighton poisoning case 1872.
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