Biomedical subjects
Publications and source records attributed to J A Reynoldson.
1 Morphine (1-200 mg/kg s.c.) reduced the incidence and prolonged the latency of priming-induced audiogenic siezures in a dose-dependent manner. 2 This effect was reversed by naloxone (1 and 2 mg/kg) although naloxone was itself inactive. 3 This priming-induces seizure model may be useful in the study of tolerance and physical dependence.
The effects of albendazole were assessed against Giardia duodenalis in vitro and compared with those of tinidazole and metronidazole. Trophozoite morphology, adherence and viability were markedly affected by albendazole, to a far greater extent than by either metronidazole or tinidazole. The results of this study, and in particular the superior potency of albendazole in vitro, are discussed with respect to its potential value as a new approach to the chemotherapy of giardiasis.
A capture enzyme linked immunosorbent assay (CELISA) was evaluated for its ability to detect Giardia coproantigens in the faeces of humans and dogs in the Perth metropolitan area and Aboriginal communities in Fitzroy Crossing, Western Australia. Using zinc sulphate flotation and light microscopy, Giardia cysts and/or trophozoites were observed in 8 of 57 (14%) human stool samples from Perth and 21 of 55 (38%) stool samples from Fitzroy Crossing, after 2 separate examinations. Analysis of diagnostic sensitivity using the ELISA revealed that coproantigens were detected in all 29 human samples (100%) in which Giardia cysts and/or trophozoites were also present. Coproantigens were detected in one further sample from Perth and in 3 samples from Fitzroy Crossing in which no Giardia cyst or trophozoite was observed. The specificity of the test, as defined using Fitzroy Crossing samples free from Giardia, was 91%. The assay did not cross-react with Giardia-free stool samples containing Hymenolepis nana, Entamoeba coli, E. hartmanni, Chilomastix mesnili or Ancylostoma duodenale. Giardia cysts and/or trophozoites were also observed in 11 of 32 dog faecal samples (34%) in Perth and 11 of 29 dog samples (38%) in Fitzroy Crossing, after one zinc sulphate examination. The sensitivity of the ELISA for dogs was 64% and 55% for Perth and Fitzroy Crossing specimens respectively. The specificity was 95% when Fitzroy Crossing samples were used. Other parasites observed in Giardia-free faecal samples from dogs which did not produce a positive reaction with the kit were Ancylostoma caninum, Sarcocystis sp. and Isospora sp.(ABSTRACT TRUNCATED AT 250 WORDS)
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1. Cardiovascular reflexes to intravenous adrenaline and histamine and to carotid occlusion were studied in the renal vasculature, and direct effects of noradrenaline and clinidoine were compared in renal and hindlimb vascular beds in anaesthetized cats. 2. Unlike its reported effects on cardiovascular reflexes in the hindlimbs, clonidine depressed all three reflexes in the kidneys. 3. Noradrenaline caused vasoconstriction when given directly into both renal and hindlimb circulartions, but clonidine produced vasoconstriction only in the hindlimb vascular bed. 4. These results suggest that alpha-adrenoceptors in the reanl vasculature may be different from those in the hindlimbs, and that the cardiovascular reflexes in these two areas are under different control.
Blood pressure and heart rate were recorded continuously in methoxyflurane anaesthetized dogs. Amitraz (i.v.) caused a dose-dependent rise in blood pressure with a fall in heart rate at lower doses. Pressor responses to amitraz were reduced by phentolamine and slightly enhanced by atropine and hexamethonium, while bradycardia was reduced by phentolamine, atropine and hexamethonium. Amitraz reduced the responses to acetylcholine and enhanced pressor responses to tyramine, while reducing bradycardia. Pressor responses to DMPP were reduced, but there was little effect on responses to noradrenaline, isoprenaline or histamine. It is possible that amitraz exerts its cardiovascular effects by stimulation of alpha 2-adrenoceptors and has some similarities to clonidine and xylazine in action.