Search PubMed⌕ Search

Biomedical subjects

A Bishop

Publications and source records attributed to A Bishop.

87 records · Page 5Linked to original sources
PubMed1975

Development of olfactory-guided behavior in the golden hamster.

Hamster pups were tested for an odor preference every day from 1-16 days of age with shavings from their home cage and with clean wood shavings. The hamster pups showed a clear preference for their home cage shavings by 8 days of age. They were then tested for preferences with other odor combinations. Tests for preference with other odor pairs indicate that this preference is due to a change in the hamsters rather than a change in the stimulus. In these tests the hamster pups did not demonstrate a preference for their home shavings over shavings in which a nonlactating female had lived. Further tests will have to be done to determine how specific the hamster pup's olfactory preferences are.

Age Factors↗
PubMedDate not supplied

Preclinical pharmacokinetics and metabolism of a potent non-nucleoside inhibitor of the hepatitis C virus NS5B polymerase.

The disposition of compound A, a potent inhibitor of the hepatitis C virus (HCV) NS5B polymerase, was characterized in animals in support of its selection for further development. Compound A exhibited marked species differences in pharmacokinetics. Plasma clearance was 44 ml min-1 kg-1 in rats, 9 ml min-1 kg-1 in dogs and 16 ml min-1 kg-1 in rhesus monkeys. Oral bioavailability was low in rats (10%) but significantly higher in dogs (52%) and monkeys (26%). Compound A was eliminated primarily by metabolism in rats, with biliary excretion accounting for 30% of its clearance. Metabolism was mainly mediated by cyclohexyl hydroxylation, with N-deethylation and acyl glucuronide formation constituting minor metabolic pathways. Qualitatively, the same metabolites were identified using in vitro systems from all species studied, including humans. The low oral bioavailability of compound A in rats was mostly due to poor intestinal absorption. This conclusion was borne out by the findings that hepatic extraction in the rat was only 30%, intraperitoneal bioavailability was good, and compound A was poorly absorbed from the rat isolated intestinal loop, with no detectable intestinal metabolism. Compound A was not an inhibitor of major human cytochrome P450 enzymes, indicating minimal potential for clinical drug-drug interactions. The metabolic clearance of compound A in rat, dog and monkey hepatocytes correlated with the systemic clearance observed in these species. Since compound A was very stable in human hepatocytes, the results suggest that it will be a low clearance drug in humans.

Animals↗
PubMedDate not supplied

The prognosis of photosensitivity.

Since 1968, annual EEG recordings during photic stimulation using a standardised technique have been made on photosensitive patients and siblings. In 1983, 72 were aged greater than or equal to 20 years and 14 were aged 16-19 years. Mean duration of follow-up was 9.8 +/- 4.8 years. Seventy-five patients were treated with sodium valproate (VPA), which was withdrawn in 15 but restarted in eight because of return of photosensitivity. Eighty-two patients had seizures at some time; at follow-up 58 were receiving monotherapy with VPA, seven were receiving comedication, and three were taking other drugs. Fifty-four of them were seizure free, as were 10 of the 15 who were not being treated with drugs. Photosensitivity disappeared in 44 of 65 patients at a mean dosage of VPA at 21.5 +/- 6 mg/kg day. In 55 of 86 patients photosensitivity was no longer present at follow-up; in 18, slight abnormality was evoked by intermittent photic stimulation, and in 13, photoconvulsive responses were still present. Eighteen patients were not receiving drugs, 10 of them being no longer photosensitive at the mean age of 24.5 +/- 4.9 years. Thirty-one treated and untreated patients were still photosensitive at age 21.5 +/- 3.4 years. Photosensitivity disappeared earlier in those treated with VPA than in the untreated. Spontaneous remission in the treated cases may have occurred at 22.9 +/- 2.5 years of age. Photosensitivity appears around puberty and may disappear around 24 years of age. Photosensitive epilepsy is easily and rapidly controlled by VPA.

Adolescent↗