Calcium antagonism by the antioestrogen tamoxifen.

Tamoxifen, an oestrogen receptor antagonist and an effective treatment for breast carcinoma, has recently been shown to possess spasmolytic activity in smooth muscle. Tamoxifen in vitro inhibited the contraction of smooth muscle from rat myometrium and aorta produced by exogenous calcium. At the same concentration tamoxifen did not affect the uptake of calcium into the muscle.

Seminiferous epithelial function in the pubertal rat following local testicular irradiation.

The dose- and time-related responses of the irradiated seminiferous epithelium in the pubertal rat have been investigated. The threshold dose for Sertoli cell dysfunction, as assessed by serum androgen binding protein (ABP) concentrations, was estimated to be 5 Gy. A significant reduction (to less than 50% of control levels) in serum ABP was observed at 8 weeks post-irradiation, with further reductions at later times (24 and 36 weeks).

Leydig cell function in the pubertal rat following local testicular irradiation.

Dose- and time-response relationships were measured after irradiation of the pubertal rat testis with between 1 and 20 Gy of 300 kVp X-rays. The threshold dose for Leydig cell dysfunction was about 5 Gy. Dysfunction after higher doses was observed by 2 weeks post-irradiation as a dose-dependent decrease in serum testosterone (T) concentrations, and the levels were undetectable after 15 or 20 Gy.

Dose and time relationships in the endocrine response of the irradiated adult rat testis.

The dose- and time-dependent responses for the interstitial and tubular compartments in irradiated adult rat testes are described. Leydig cell dysfunction, as indicated by increased serum LH (to a maximum of 385% of control after 5 Gy) and decreased serum T (to a minimum of 30% of control after 10 Gy), was observed at 8 weeks postirradiation. Subsequent recovery of Leydig cell function was then observed, so that after 9 months serum T was normal but LH was still marginally elevated.

Transfer of passive immunity from mother to young in a teleost fish: haemagglutinating activity in the serum and eggs of plaice, Pleuronectes platessa L.

Plaice were immunized against rabbit red blood cells (rbc) and the haemagglutinating activity in their sera and eggs was isolated by gel filtration in Sephacryl S300 SF. A "heavy" (greater than 6.69 X 10(5) Daltons) and a "light" (less than 2.

Dose and time related responses of the irradiated prepubertal rat testis. II. Seminiferous epithelial function.

Dose-related effects of radiation upon the seminiferous epithelium were examined in the prepubertal rat. Marked damage to the spermatogenic cell populations was produced by doses of 5 Gy and above. As a result serum levels of FSH were increased, maximum changes being observed at 2 weeks, but levels remaining high even at 36 weeks after irradiation.

Dose and time related responses of the irradiated prepubertal rat testis. I. Leydig cell function.

The testes of prepubertal rats were locally irradiated with 300 kVp x-rays to doses of between 1 and 15 Gy. Leydig cell function was assessed between 2 and 36 weeks post-irradiation. Dysfunction was observed at two weeks as evidenced by a reduction in serum levels of testosterone to between 40 and 70% of control, with a threshold dose of about 5 Gy.

Inhibition of intestinal smooth muscle function by tamoxifen and clomiphene.

The acute in vitro effects of the oestrogen antagonists clomiphene (a racemic mixture) and tamoxifen were examined upon spasmogen induced contractions of the guinea pig ileum. Both oestrogen antagonists inhibited the contractions produced by acetylcholine, the muscarinic agonist beta-methylcholine, histamine and bradykinin in a manner which suggests non competitive antagonism. Concentration effect curves to each of the spasmogens were unaffected using 0.

Leydig cell resistance to the cytotoxic effect of ethylene dimethanesulphonate in the adult rat testis.

Weekly doses of the Leydig cell cytotoxic ethylene dimethanesulphonate (EDS) were administered to adult male rats in an attempt to study the endocrine activity of the testis in the absence of Leydig cells. One week after the first dose serum testosterone and LH concentrations and seminal vesicle weights were close to levels in castrated rats and testicular human chorionic gonadotrophin (hCG) binding was severely depressed. These changes were maintained for a further week but subsequently began to return to, but did not achieve, control levels.

Influence of growth hormone, corticosterone, corticotrophin and changes in the environmental temperature on pituitary-ovarian function in the immature rat.

The influence of various endocrine and environmental factors on pituitary-ovarian function was studied in peripubertal rats treated with pregnant mare serum gonadotrophin (PMSG). Pregnant mare serum gonadotrophin induced ovulation in rats aged 27 days provided they weighed over 60 g. The response was preceded by a marked hypersecretion of LH which was detectable by radioimmunological and biological assay methods.

A new unit for long-stay psychiatric patients: organization, attitudes and quality of care.

The present study describes and evaluates aspects of care in a new residential unit for chronic patients. The findings suggest that the unit is relatively resident-orientated in its management practices and that the staff are similarly orientated in their attitudes. Staff also hold generally optimistic attitudes to residents' potential accomplishments and consider themselves highly involved in decision-making.

Colonic motility in the postoperative period.

The effect of a laparotomy on postoperative motility in the colon has been studied in dogs. Movement has been recorded by an electrical impedance method each day after a standard laparotomy. Mean values of movement in the descending colon were reduced, not abolished, for 3 days after operation (preoperative: 34.

Changes in small bowel myoelectrical activity following laparotomy.

Recordings of the myoelectrical activity have been obtained from the small intestine of 4 dogs by means of serosally implanted electrodes. The occurrence of the activity front (phase III) of the migrating myoelectrical cycle (MMC) in the recordings obtained each day after abdominal surgery have been compared. No activity fronts were seen on postoperative days 1 and 2.

Fluprostenol-induced softening of the cervix of the pregnant rat.

Fluprostenol, an analogue of prostaglandin F2 alpha, administered s.c. to rats on day 18 of pregnancy increased cervical creep, or softness, by the following day.

The biological activity of a single dose of tamoxifen in the adult ovariectomized rat.

1 The peripheral and central activities of tamoxifen were studied in the ovariectomized adult rat, up to 16 d after a single dose of 7.0 or 0.7 mg/kg.

Simultaneous recording of myoelectrical activity and resistance from the human colon.

A system used to record myoelectrical activity from the rectosigmoid colon has been modified so that a continuous recording of electrical resistance is obtained simultaneously. Normal subjects, patients with diverticular disease and patients with the irritable colon syndrome have been studied by this method. There were variations in resistance in the form of waves for 74.

The release of pituitary gonadotrophins by luteinizing hormone releasing hormone in the intact, castrated and aspermatogenic rat.

The change in serum gonadotrophin concentration in response to synthetic Luteinizing Hormone Releasing Hormone (LHRH - 400 ng i.v.) was investigated under barbiturate anaesthesia in adult male rats either chronically castrated, rendered aspermatogenic by the administration of alpha-chlorohydrin 12-16 weeks previously (to remove inhibin), or treated with vehicle.

Hypothalamic, pituitary and uterine cytoplasmic and nuclear oestrogen receptors and their relationship to the serum concentration of tamoxifen and its metabolite, 4-hydroxytamoxifen, in the ovariectomized rat.

High-affinity oestrogen receptors were measured in the cytosol and nuclei prepared from the hypothalamus, pituitary gland and uterus of the ovariectomized rat up to 16 days after a single dose of tamoxifen or 4-hydroxytamoxifen. Tamoxifen produced a dose-related fall in the concentration of cytosol receptors in the hypothalamus, pituitary gland and uterus. Minimum values were observed after 24 h; cytosol receptor concentrations were restored slowly and only reached expected control values between 4 and 8 days and 2 and 4 days for 7.

The effect of naloxone on some neuroendocrine responses to limb ischaemia.

The finding that naloxone reverses the arterial hypotension produced by bacterial endotoxin in the rat was confirmed and the effect of naloxone on the responses to another form of injury, limb ischaemia was studied. Naloxone had no effect on the fall in blood pressure and colon temperature or on behaviour and survival after bilateral hind-limb ischaemia. The ambient temperature threshold for the onset of shivering was depressed by limb ischaemia as in untreated rats.