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Biomedical subjects

B Grant

Publications and source records attributed to B Grant.

70 records · Page 4Linked to original sources

Characterization of the equine platelet aggregation response.

Equine platelet aggregation responses to bovine collagen, adenosine diphosphate (ADP), serotonin, epinephrine, and arachidonate in a platelet aggregometer were recorded. Equine platelets exhibited irreversible aggregation when incubated with ADP at a final concentration of 10 microM and bovine collagen. A secondary aggregation wave was recorded from platelets from certain horses at final ADP concentrations of 1 to 5 microM. Serotonin and arachidonate induced a weak reversible aggregation response, but a response was not observed following epinephrine addition. Equine platelet aggregation was influenced by concentration of anticoagulant (sodium citrate). Platelet aggregation responses at 37 C were indistinguishable from those recorded at 39 C. Platelet aggregation responses also were altered if the aggregation tests were not performed within 4 hours of blood sample acquisition. An assessment of platelet aggregation from multiple blood samples from the same horse indicated that the procedures described provide a reliable method to assess equine platelet aggregation in vitro.

Adenosine Diphosphate↗

Phenylbutazone inhibition of equine platelet function.

Nonsteroidal anti-inflammatory drugs impair platelet aggregation and secretion in man, pigs, and rabbits and inhibit platelet thromboxane/prostaglandin synthesis. The present investigation studied the effects of phenylbutazone on platelet aggregation and bleeding times in the horse. Aggregation responses to adenosine diphosphate and collagen were markedly impaired 15 minutes and 2 hours after treatment, but 4 hours after treatment, platelet responses approximated those prior to treatment. The in vivo effect of phenylbutazone correlated with its plasma concentrations. Phenylbutazone, like aspirin, appeared to exert its effect by inhibiting thromboxane/prostaglandin synthesis, because thrombin-induced malondialdehyde formation was inhibited. However, unlike aspirin, free arachidonate-induced malondialdehyde synthesis was reduced but not eliminated, which suggested that phenylbutazone may have more than one site of action. Although collagen-induced platelet aggregation was impaired, a response was still present, and bleeding times were not altered by phenylbutazone treatment. To account for these findings, it is proposed that equine platelets can respond to collagen by thromboxane/prostaglandin independent pathways. The physiologic and pathophysiologic importance of these findings is discussed.

Adenosine Diphosphate↗

The effect of oral local anaesthetic and alkali on basal and food-stimulated serum gastrin levels in patients with duodenal ulcer.

Twelve patients with duodenal ulcers were each given on separate days and in random order an oral local anaesthetic (oxethazaine), an alkali (aluminium hydroxide and magnesium hydroxide), a combination of local anaesthetic and alkali (Mucaine), and a similar volume of water (control) followed one hour later by a solution of meat extract (Oxo). The effect of these treatments on serum gastrin levels was measured. None of the treatments altered the normal basal gastrin levels. The gastrin response to ingestion of protein extract was significantly lower in patients who had been pre-treated with local anaesthetic than those who had received alkali, with or without local anaesthetic, or water.

Administration, Oral↗

Electrogoniometric analysis of equine metacarpophalangeal joint lameness.

Electrogoniometry was used qualitively and quantitatively to assess the movements of the normal and pathologic metacarpophalangeal joints of selected horses. A total of 4 Thoroughbreds, 1 normal and 3 with clinical and radiographic changes in the metacarpophalangeal joints of 1 limb, were evaluated at the walk and trot. Goniograms of the affected joints were compared with those of the normal horse and the normal contralateral metacarpophangeal joint. Qualitative asymmetry was recognized on the goniograms, and the ranges of motion were quantified and related to the clinical and radiologic observations.

Animals↗

Cognitive functioning in the last year of life as a function of age, gender, and race.

Research has shown that many factors affect cognitive functioning. In this study cognitive functioning was analyzed using proxy reports concerning 17,135 decedents included in the 1993 National Followback Mortality Study conducted for the National Center for Health Statistics. These responses form a representative sample of all U.S. residents over age 15 who died in 1993 (except for those in South Dakota, which did not participate). Decedents had more difficulty understanding where they were than remembering what year it was or in recognizing family members. Logistic regression models found that age, gender, and race were the most important predictors of these basic cognitive functions. Although increasing age was associated with more cognitive difficulties, men had fewer deficits than women and Black Americans tended to have fewer deficits than White Americans. Possible reasons for these findings are discussed as well as some general implications for health service provision.

Black or African American↗