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J D Allen

Publications and source records attributed to J D Allen.

At least 109 records · Page 6Linked to original sources
PubMed1983

An assessment of adjunctive behavior in a safety-signal paradigm.

Three groups of rats were exposed to 0.4 mA shock presentations on a VT 30-sec schedule. Behavior was monitored during 35-sec shock-free periods inserted randomly after 15 of the 60 shocks per session. In the no-signal and random-signal control groups the behavior patterns which developed were similar to defense or fear reactions. In the safety-signal group, in which a tone signalled the 35-sec no-shock periods, a pattern of adjunctive and facultative behaviors developed including marked increases in grooming and rearing behaviors. No evidence of adjunctive drinking was found in any of the three groups.

Animals↗
PubMed1982

Evaluation of a hardjo-pomona vaccine to prevent leptospiruria in cattle exposed to a natural challenge with Leptospira interrogans serovar hardjo.

The efficacy of a vaccine against Leptospira interrogans serovar pomona and Leptospira interrogans serovar hardjo was evaluated in a group of dairy heifers that were serologically negative at the time of vaccination and later subjected to natural challenge with L. interogans serovar hardjo. Thirty-nine heifers were vaccinated twice, at a one-month interval, with a commercially prepared bivalent vaccine, while 43 unvaccinated heifers were used as controls. After vaccination, microscopic agglutination (MA) titres of serums to L. interrogans serovar hardjo ranged from 32 to 512, and those to L. interrogans serovar pomona ranged from 32 to 2048. Titres resulting from vaccination were short-lived and after the first vaccination the serums of 95% of vaccinated heifers did not react in the MA test by 24 weeks. The first indication of infection in the heifers was noted at week 6, and by week 16, elevated MA titres (greater than or equal to 128) to L. interrogans serovar hardjo had occurred in 62% of unvaccinated heifers and had increased to 85% by week 24. At week 18, 18% of the vaccinated heifers and 56% of the unvaccinated heifers had leptospiruria (p less than 0.01); after 22 weeks, 13% of the vaccinated heifers and 58% of the unvaccinated heifers showed evidence of leptospiruria (p less than 0.01).

Agglutination Tests↗
PubMed1981

Determination of mortality risk in obstructive pulmonary syndromes: physical examination compared with measurement of forced expired volume in one second.

A standardised physical examination based on four clinical signs was compared with the FEV1 with regard to ability to determine five-year mortality risk in subjects with varying degrees of obstructive airway disease. Both evaluation methods identified low, intermediate, and high risk groups within the population studied. Individuals with no positive physical signs, or with an FEV1 of 70% of predicted or more had mortality not significantly greater than that predicted on the basis of standard mortality tables. There was no difference between the FEV1 and the physical examination in ability to predict mortality.

Adult↗
PubMed1981

Argyria.

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Aged↗
PubMed1979

An improved fluorimetric determination of alpha-mannosidase activity in bovine plasma.

This paper describes a manual fluorimetric method for the assay of acidic alpha-mannosidase activity in bovine plasma. The optimum conditions for the assay of this enzyme were studied. The assay method devised includes the addition of zinc to the substrate, which stimulates activity by approximately twofold, and reduces the optimum substrate concentration. This latter feature affords considerable cost saving in each test. We have also shown that the alpha-mannosidase activity in lithium heparin plasma, EDTA plasma and blood serum is the same whether the plasma/serum is separated from the cells/clot at 6, 20 or 25 hours after sample collection. This has eliminated the previous necessity of having to deliver whole blood samples to the laboratory within 6 hours of collection. Furthermore samples for the supplementary neutrophil assay can now be taken at the same time as those for the plasma test, and both samples forwarded together. The plasma alpha-mannosidase assay is a rapid and reliable screening test for the mannosidosis genotype and for detecting carrier animals. Carrying out this plasma assay in conjunction with the more definitive neutrophil assay provides a reliable method of distinguishing homozygotes and heterozygotes from normal animals.

Animals↗