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G V Groom

Publications and source records attributed to G V Groom.

At least 19 recordsLinked to original sources
PubMed1984

Analyses for progesterone in serum by gas chromatography/mass spectrometry: target data for external quality assessment of routine assays.

We describe a procedure for measuring progesterone in plasma and serum by isotope dilution and mass spectrometry. Extraction with use of a microcellulose-coupled antiserum is followed by conversion to the 3-enol heptafluorobutyrate and analysis by gas chromatography/mass spectrometry (GC/MS) with selected ion monitoring, at a resolution of 5000. Interassay CVs were 1.5 to 5.4% for the concentration range 13 to 43 nmol/L. Analyses of various serum volumes showed excellent linearity. Accurate determination of progesterone added to serum was demonstrated. Plasma and serum pools were analyzed to provide target data for use in the U.K. national external quality-assessment scheme for progesterone assays. Direct, non-extraction radioimmunoassays and those incorporating solvent extraction both showed a positive bias with respect to data obtained by the present procedure, but the bias was more marked with the direct assays.

Female↗
PubMed1983

The effect of tamoxifen on plasma growth hormone and prolactin in postmenopausal women with advanced breast cancer.

The effect of tamoxifen on serum levels of basal prolactin and basal and stimulated growth hormone was assessed in 10 women with advanced breast cancer prior to and after 1 and 8 weeks of treatment. Tamoxifen had no effect on basal levels of either hormone or on insulin-stimulated growth hormone. Two of 4 patients undergoing arginine provocation testing had a partial response to tamoxifen and both exhibited marked diminution of growth hormone stimulation which was not seen in the non-responders.

Aged↗
PubMed1983

External quality assessment of assays for cortisol in plasma: use of target data obtained by gas chromatography/mass spectrometry.

We describe procedures for measuring cortisol in plasma and serum by isotope dilution and mass spectrometry. A method that incorporated solvent extraction, derivatization, and gas chromatography/high-resolution mass spectrometry provided data of good precision; interassay CVs were generally 3 to 4% for the concentration range of 100-650 nmol/L. Replacing solvent extraction with extraction on a column of Lipidex 1000 or extraction by immunoadsorption yielded data in excellent agreement with the first method. Plasma and serum pools were analyzed to provide target data for use in the U.K. National External Quality Assessment Scheme for cortisol assays. Routine laboratory assays, as judged by comparison with mass-spectrometric data, were generally positively biased except for analysis of a charcoal-stripped plasma supplemented with cortisol. The results emphasize the importance of using unadulterated plasma or serum pools in assessments of steroid assay procedures.

Charcoal↗
PubMed1981

The effect on plasma prolactin, growth hormone and luteinising hormone concentrations of single oral doses or propranolol and tolamolol in normal man.

In a placebo controlled double-blind study in six healthy male volunteers the effects of single oral doses of 100 mg and 200 mg of tolamolol on plasma concentrations of prolactin, growth hormone and luteinising hormone were investigated. In a second placebo controlled single-blind study in a further six healthy male volunteers the effects of single oral doses of 200 mg tolamolol and 160 mg propranolol on the same plasma hormone concentrations were compared. A dose dependent increase in plasma prolactin concentration was demonstrated after tolamolol. The increase in plasma prolactin concentration was not evident after propranolol. Plasma growth hormone and luteinising hormone concentrations were not significantly changed by either propranolol or tolamolol.

Administration, Oral↗
PubMed1981

The investigation and treatment of germ cell tumours of the testis.

Fifty-five per cent of patients presenting with testicular tumours in 1973--78 had teratomata. A history of undescended testis was only found in patients with seminoma. The right testis was the more frequent site of the primary. Radiation doses of 3400 cGy (rad) in 20 fractions for seminoma and 4500 cGy in 25 fractions for teratoma were well tolerated and sterilised microscopic disease in the majority of patients. Forty-two of 44 seminoma patients are alive and free from disease at a median follow-up of three years. Only 15 of 22 Stage I teratoma patients remain disease free, however. A combination of vinblastine and bleomycin produced 12 complete remissions in 30 patients with metastatic teratoma. Survival was significantly longer for patients achieving complete remission. Although six of the complete responders remain alive, only three are in their initial complete remission. Alpha-foeto-protein and/or beta-subunit human chorionic gonadotrophin levels were elevated in almost all cases of advanced teratoma. The biological half-life of alpha-foeto-protein in the serum is less than six days. The value of these markers in predicting relapse was limited in this series. The doubling of complete response rate in metastatic teratomata that can be achieved by adding cis-platinum to the vinblastine/bleomycin combination, together with the propensity for extranodal metastasis shown by testicular teratomata, suggest that adjuvant chemotherapy should be explored in early disease.

Adult↗
PubMed1981

The effects of propranolol and acebutolol on the overnight plasma levels of anterior pituitary and related hormones.

1 The effects of single evening doses of the beta-adrenoceptor blocking agents propranolol (80 mg orally) and acebutolol (200 mg orally) on plasma levels throughout the night of prolactin, growth hormone, luteinising hormone, follicle stimulating hormone, cortisol and testosterone have been studied in seven healthy male volunteers. 2 Three way analysis of variance showed that acebutolol significantly reduced circulating levels of prolactin and follicle stimulating hormone, but did not alter the levels of the other hormones studied. 3 Propranolol significantly reduced follicle stimulating hormone and testosterone, and significantly increased circulating levels of cortisol, but caused no change in the other hormones studied. 4 Prolactin, luteinising hormone, testosterone and cortisol showed a significant variation with time indicating the existence of a diurnal rhythm in the pattern of their secretion. 5 There was a significant inter-subject variability in all the hormones studied. 6 There was a significant between-subject variation in response to both propranolol and acebutolol. 7 Different subjects showed significant variations with respect to time in prolactin, growth hormone and cortisol levels. 8 Neither propranolol nor acebutolol significantly altered the time course of secretion of any of the hormones studied. 9 Possible relationships of these beta-adrenoceptor blocker-induced changes in anterior pituitary and related hormones to the antihypertensive mechanism of acebutolol and propranolol are discussed.

Acebutolol↗
PubMed1981

The effect of chronic propranolol treatment on overnight plasma levels of anterior pituitary and related hormones.

1 Treatment of eight healthy males with propranolol (80 mg twice daily) for 6 weeks resulted in a significant reduction in overnight plasma levels of prolactin and LH. 2 Plasma testosterone levels were elevated whilst GH and cortisol were unchanged by such treatment. 3 Measurement of overnight hormone levels 48 h after discontinuing treatment showed no evidence of a 'rebound' phenomenon. 4 Cortisol, GH, prolactin, and testosterone plasma levels all showed time dependent changes: propranolol treatment significantly altered the time course of cortisol but not of the other hormones. 5 The effects of chronic propranolol treatment are discussed in terms of a probable direct central action of the drug. In addition the lowered plasma prolactin levels may directly contribute to the hypotensive action of propranolol.

Adult↗
PubMed1981

Characterisation of breast skin temperature rhythms of women in relation to menstrual status.

Circadian breast skin temperature rhythms were characterised throughout the menstrual cycle, for various locations on the left breast of ambulatory women. All subjects exhibited highly significant circadian rhythms (P less than 0.001). Changes in rhythm parameters, such as the mesor, amplitude and acrophase, were observed during the menstrual cycle. No consistent trend in these rhythm parameters was observed between subjects in relation to menstrual cycle stage. Experimental and statistical techniques used to characterise circadian rhythms in pre-menopausal women were applied to a post-menopausal woman with primary breast cancer. Comparison of rhythm parameters associated with the tumour area and corresponding site on the contralateral breast showed abnormal thermal characteristics such as elevated mesor values, decreased amplitude as well as changes in the timing of the acrophase. These properties may be exploited for the early detection of breast cancer. The project also involved the design and testing of an ambulatory device, known as the 'chronobra', for the measurement of breast skin temperature. The performance of the chronobra was in close agreement with reliable, conventional equipment. The chronobra now allows studies of breast skin temperature rhythms associated with breast disease to be extended.

Adolescent↗
PubMed1980

Prolactin responses to histamine H2 receptor antagonists.

We have compared the effects of cimetidine and SK&F 92994, a new more potent histamine H2 receptor antagonist, on serum prolactin, and also assessed the effect of the H2 receptor agonist impromidine on the response to cimetidine. As previously reported, cimetidine 200 mg given as an iv bolus dose produced a marked rise in serum prolactin, but 50 mg and 200 mg of SK&F 92994 given by the same route had no effect. Iv infusion of impromidine 10 microgram kg-1h-1 failed to modify the prolactin response to cimetidine. It is concluded that the rise in serum prolactin following iv administration of cimetidine may be due to a specific property of cimetidine. An effect mediated via histaminergic pathways within the central nervous system, although less likely, cannot be excluded.

Cimetidine↗
PubMed1980

The interrelationship between hormones, psychotropic drugs and the opiate receptor--a pilot study.

Earlier reports had shown pronounced effects of clomipramine on plasma pituitary and gonadal hormone levels. In a continuation of these studies no change could be seen in rat plasma corticosterone levels following long-term, toxic administration of the drug despite a marked adrenal hyperplasia. It had been suggested that the action of clomipramine might be potentiated through the opiate receptor. Initial experiments using a rat model system have shown that morphine increased plasma prolactin and reduced plasma luteinizing hormone levels in vivo and that these effects could be overcome by naloxone. No direct effect of enkephalins was observed on rat pituitary organ cultures. The results are discussed in the light of recent findings of the relationship between properties of the opiate receptor and the observed side effects of tricyclic antidepressant therapy.

Animals↗
PubMed1980

The effect of naloxone on psychotropic drug-induced prolactin, growth hormone and cortisol secretion--a preliminary report.

In the course of studies of the effects of interaction between opiate receptors and psychotropic drugs, plasma hormone levels were measured in a group of psychiatric patients on steady-state antidepressant or neuroleptic drugs following intravenous naloxone administration. Plasma prolactin levels were depressed after 10 minutes but at 1 hour rebound elevation was observed in some subjects. Plasma growth hormone and cortisol levels were elevated from 10 minutes to 1 hour following naloxone. These results are discussed with respect to the possible mode of action of psychotropic drugs. In a volunteer given oral clomipramine a marked reduction of the plasma level of the drug was observed following the insertion of an indwelling cannula kept patent with citrate. The use of this technique to study the effect of drugs, especially in single-dose volunteer studies, calls for further critical evaluation.

Adult↗
PubMed1979

Prolactin responses to cimetidine.

1 An intravenous injection of cimetidine 400 mg to four healthy male subjects resulted in high blood concentrations of cimetidine and a rapid three-fold increase in serum prolactin. 2 This effect was prevented by pretreatment with bromocriptine. 3 No increase in prolactin followed a single oral dose of cimetidine 800 mg administered to a different group of healthy male subjects. The mean peak blood concentration of cimetidine was less than 20% of that achieved with 400 mg i.v. 4 Only isolated reports have been received of gynaecomastia or galactorrhoea occurring during cimetidine treatment. In three of seven cases studied there was associated hyperprolactinaemia. This may be an idiosyncratic response at the lower blood concentration of cimetidine associated with oral therapeutic dose regimens.

Administration, Oral↗