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Biomedical subjects

J M Hall

Publications and source records attributed to J M Hall.

At least 163 records · Page 9Linked to original sources
PubMed1983

Plasma amine and hormone changes in 'post-partum blues'.

The relationship between hormone levels, plasma catecholamines, and mood disturbances has been investigated in 44 patients during days 2 to 5 of the immediate post-partum period. Fifty-two per cent of the mothers showed periods of emotional lability although there was no significant correlation between plasma concentrations of FSH, prolactin, oestrone, oestradiol, cortisol, or progesterone and the incidence of post-partum blues. In contrast there was a significant reduction of circulating catecholamines which correlated with mood disturbances. Women who experienced only a single day of post-partum blues had significantly lower levels of noradrenaline and adrenaline on that day compared with preceding or subsequent days.

Adult↗
PubMed1983

Use of cholate/sodium chloride for solubilisation of brain D2 dopamine receptors.

The use of cholate (in the presence of sodium chloride) is described for solubilising brain D2 dopamine receptors. The method described gives in high yield a preparation of solubilised D2 receptors which when assayed by [3H]spiperone binding show little interference from nonspecific and nonstereospecific binding sites. Characterisation by ultrafiltration, electron microscopy, gel filtration, and sucrose density gradient centrifugation has been achieved, showing the receptors to be truly solubilised. Pharmacological characterisation using [3H]spiperone binding suggested the presence of serotonergic S2 receptors in addition to D2 receptors. The pharmacological properties of the solubilised D2 receptors show a good correlation with those of membrane-bound receptors, although ligand binding affinities are lower in the solubilised preparation.

Animals↗
PubMed1983

Effects of chronic treatment with oestrogen, an oestrogen antagonist and a potent luteinizing hormone releasing hormone agonist analogue on pituitary responsiveness to luteinizing hormone releasing hormone in the rat.

The rise in gonadotrophin release which occurs after ovariectomy is caused by steroid withdrawal resulting in an enhanced pituitary responsiveness to LH releasing hormone (LHRH) associated with increased LHRH release and pituitary LHRH binding. The effects of oestrogen replacement after ovariectomy and chronic treatment of intact rats with an oestrogen antagonist, tamoxifen, on LH release and in-vitro pituitary responses to LHRH have been investigated. Capsules containing crystalline oestradiol, implanted at the time of ovariectomy, completely inhibited the rise in LH release although pituitary responsiveness was greater after 10 days in the oestrogen-treated rats than in untreated ovariectomized controls. On day 4 after ovariectomy pituitary responses to LHRH were comparable in both treated and untreated groups although in both groups the responses were greater than those measured in intact dioestrous rats. Treatment with tamoxifen over a 4-day period also augmented pituitary responsiveness but only at the lowest dose (0.5 mg/kg); no effect on serum LH concentrations was observed. Higher doses of the antagonist (1 and 2 mg/kg) did not affect pituitary responses, although the highest dose did cause a significant rise in serum LH. Treatment with a daily dose of 50 ng [D-Ser(But)6]LHRH(1-9)nonapeptide-ethylamide, starting on the day of ovariectomy, markedly attenuated the LH responses to LHRH ex vivo at days 2, 4 and 10 after ovariectomy. In contrast, the analogue treatment did not abolish the rise in LH release but this was proportionately less than in controls.

Animals↗
PubMed1983

Fc and complement receptor lymphocytes in the ocular tissues of rabbits immunized intravitreally with ovalbumin.

The numbers of antibody producing cells (PFC) and the percentages of Fc receptor cells (FcR) and complement receptor cells (CRL) in the ocular and lymphoid tissues of rabbits immunized intravitreally with ovalbumin were determined. Antibody-producing cells were detected first in the lymph nodes and then in the uveas and corneas. The uveal tracts contained more than 50% FcR early in the antibody response, but the percentages returned to normal levels during the second postinjection week. An apparent inverse relationship between the numbers of ocular PFC and the percentages of ocular FcR was noted. The percentages of CRL in the spleens and lymph nodes were similar to those reported by other investigators. No obvious correlation between CRL percentages in the ocular tissues and the numbers of PFC was seen. The "T-" or "B-" cell nature of the ocular FcR and their possible functions in regulating ocular immune responses are yet to be determined.

Animals↗
PubMed1982

Fluorine compounds in anaesthesia (9). Examination of six aliphatic compounds and four ethers.

Six heavily fluorinated aliphatic compounds and four heavily fluorinated derivatives of diethyl ether have been examined as anaesthetics, using mice. Two compounds are felt to be worth further examination. These are 1,1,1,-trifluoro-2,2-dichloroethane (halothane with the bromine atom replaced by a second chlorine) and 1,1,2,2,4,5,5-heptafluoro-3-oxapentane (ordinary diethyl ether with seven hydrogen atoms replaced by fluorine).

Anesthesia, Inhalation↗
PubMed1982

Studies on the antitumour effects of N-137.

The antitumour properties of the drug N-137 were assessed in vivo in two murine T lymphoma models and two naturally metastatic hamster fibrosarcomas of Herpesvirus hominis aetiology. N-137 therapy caused a significant delay in the subcutaneous growth rate of both lymphomas (EL4 and TLX9) and in many cases completely prevented tumour appearance when administered at high doses. The antitumour effect observed in both systems was shown to be dose dependent. In contrast, N-137 therapy failed to influence the growth of two hamster fibrosarcomas (HSV-333-2-26 Met A and Met B lines), and drug administration prior to or following resection of Met B tumours failed to influence the development of natural metastases as measured by monitoring animal survival.

Animals↗
PubMed1981

The pharmacokinetics of levonorgestrel and ethynylestradiol in women - studies with Ovran and Ovranette.

A radioimmunoassay for levonorgestrel (Ng), which is applicable to plasma samples obtained from women who have taken a combination type oral contraceptive, has been developed and fully validated. Plasma concentrations of Ng rise to a peak of 3.6 ng/ml after an oral dose of 150 microgram and to 5.0 ng/ml after a 250 microgram dose. Following the intravenous administration of Ng, plasma concentrations of the steroid decline bi-exponentially with mean half-lives of 0.76 and 11.55 hours. Comparison of the results of the intravenous and oral administration of the steroid show a mean systemic bioavailability of 89% after the 150 microgram dose and 99% after a 250 microgram dose. This difference was not statistically significant. The values for volume of distribution were approximately half and the values for plasma clearance three times less than that previously reported for norethindrone. The plasma ethynylestradiol levels were also measured following administration of 30 microgram both intravenously and orally. The bioavailability and kinetics were similar to that previously reported for a 50 microgram dose. The peak values after oral dosing were 103 pg/ml and were reached by 1.0 hour in all subjects.

Adult↗
PubMed1981

The in vitro metabolism of ethinyloestradiol, mestranol and levonorgestrel by human jejunal mucosa.

1 Ethinyloestradiol was extensively metabolised in vitro by human jejunal mucosa to form ethinyloestradiol sulphate. 2 The amount of conjugation was directly related to the weight of biopsy tissue. 3 The degree of conjugation of mestranol and levonorgestrel was much lower than for ethinyloestradiol suggesting that the 17-position of the steroid nucleus is relatively inaccessible for conjugation. 4 No Phase I metabolism of ethinyloestradiol or levonorgestrel was apparent in the conditions used in these experiments.

Adult↗
PubMed1981

Topical ocular immunization of rabbits.

New Zealand white rabbits were immunized by dropping ovalbumin (100 mg/ml) into the conjunctival sac four times daily for 3 weeks. Many rabbits developed detectable hemagglutinating antibody by day 7 and all had antibody by day 14. The serum antibody persisted for at least 6 months after the beginning of immunization. Plaque-forming cells were found in the lymph nodes, spleens, the conjunctiva, and limbal tissue. Fc receptor cells were found in all the tissues examined, but the numbers of Fc receptors cells did not seem to have any relationship to the numbers of plaque-forming cells in the same tissues.

Animals↗
PubMed1980

The effect of rifampicin on the pharmacokinetics of ethynylestradiol in women.

A single dose of Minovlar (50 microgram ethynylestradiol (EE) and 1 mg norethindrone acetate) was given to seven women during treatment with rifampicin (450-600 mg/day) and again one month after stopping rifampicin. Blood samples were taken at intervals over a 24-hour period. The area under the plasma EE versus time curve increased significantly on stopping rifampicin from 1014 +/- 317 pg/ml x h (mean +/- SE) to 1747 +/- 218 pg/ml x h (p less than 0.01). The terminal plasma half-life increased from 2.9 +/- 0.8 h to 6.3 +/- 1.4 h (p less than 0.005). The sex hormone binding globulin (S.H.B.G.) capacity was also reduced from 213.4 +/- 11.5 nmoles to 129.0 +/- 7.7 nmoles/1 after stopping rifampicin. In one patient starting rifampicin who was taking Minovlar as a long-term oral contraceptive, a fall in the plasma EE concentration was associated with a rise in the plasma follicle stimulating hormone concentration. These effects of rifampicin on EE pharmacokinetics are consistent with induction of the microsomal enzymes that metabolise EE.

Adolescent↗
PubMed1980

Idiopathic retroperitoneal fibrosis with functional duodenal obstruction.

Idiopathic retroperitoneal fibrosis with duodenal obstruction is a rarely reported clinical entity. The presenting symptoms of nausea, vomiting, weight loss, and progressive fatigability can be easily overlooked if attention is focused on the more prominent symptoms of low back and flank pain. Duodenal obstruction can present several months after the initial diagnosis of retroperitoneal fibrosis. Nutritional support before surgical correction is imperative.

Duodenal Obstruction↗