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Biomedical subjects

R G Cooke

Publications and source records attributed to R G Cooke.

At least 55 records · Page 3Linked to original sources
PubMed1991

Effect of oxytocin on plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F2 alpha during the oestrous cycle and early pregnancy in the goat.

The effect of subcutaneous oxytocin on plasma concentrations of 13,14-dihydro-15-keto-prostaglandin (PG) F2 alpha (PGFM) was examined in the goat at various periods during the oestrous cycle and early pregnancy. 100 i.u. oxytocin was administered daily for 4 day, the dose being divided and given at 0900 and 2100 h; PGFM concentrations were assessed after the first treatment of each day. On days 3-6 (oestrus, day 0) PGFM concentrations increased significantly (P less than 0.001) within 15 minutes and both non-pregnant and mated goats exhibited oestrus behaviour by day 7. Significant (P less than 0.01) increases in PGFM were also produced on days 7-10, in both non-pregnant and pregnant goats, but the responses diminished from day 7 to day 10; only one goat (non-pregnant) came into oestrus. There was a marked difference in response between groups, however, during days 12-15. In non-pregnant goats significant (P less than 0.05) increases in PGFM were detected on days 13-15, but in pregnant animals oxytocin was without effect. Similarly, oxytocin did not increase PGFM concentrations on days 17-20 of pregnancy. However, uterine responsiveness reappeared in pregnant goats with significant (P less than 0.01) increases in PGFM on days 24 and 25.

Animals↗
PubMed1990

MS in the Faroe Islands and the possible protective effect of early childhood exposure to the "MS agent".

Epidemiologic data on multiple sclerosis (MS) in the Faroe Islands have been interpreted by the original investigators as supporting a particular infectious disease model. They suggest that MS occurs as a late consequence of extended exposure to an infectious agent which cannot be transmitted to subjects younger than 11 years of age. However, the Faroes data may better fit an alternate model, in which MS results from delayed primary exposure to an infectious agent which more commonly produces benign illness and protection against MS in subjects who are exposed in infancy or early childhood.

Adolescent↗
PubMed1990

Effect of concurrent medical illness on dexamethasone suppression test results in depressed inpatients.

A retrospective evaluation of the clinical records of 138 depressed patients, who received the dexamethasone suppression test (DST) as part of a standardized physical and psychiatric assessment protocol, revealed that 60 had acute, chronic (mild or severe), stable or remitted medical conditions. The proportion of DST nonsuppressors did not differ between depressed subjects with medical conditions (45% nonsuppressors) and those without (34.6% nonsuppressors; p greater than 0.2). However, all of the six subjects with acute or chronic-severe medical conditions were found to be nonsuppressors (p = 0.003). These results may help clarify the medical exclusion criteria for the clinical application of the DST.

Adult↗
PubMed1989

Testosterone secretion during early pregnancy in the goat.

Increased peripheral concentrations of testosterone were detected on Days 12 and 13 of the estrous cycle (estrus=Day 0), at the onset of luteolysis in goats. In pregnant goats no increases in testosterone occurred between Days 10 and 18 after mating, and luteal regression was inhibited. It is suggested that testosterone is required for luteolysis in goats, and that the absence of any increase in testosterone concentrations is another manifestation of the mechanisms involved in the maternal recognition of pregnancy.

Journal Article↗
PubMed1989

Epstein-Barr virus as a cause of autoimmune disease and other medical morbidity in patients with affective disorders.

We hypothesize that psychiatric patients suffering from the major affective disorders (depression and manic-depressive illness) may commonly also suffer from a chronic active infection with the Epstein-Barr virus. This infection would be a consequence of the immune dysfunction known to be associated with these disorders of mood. According to this hypothesis, the increased medical morbidity and mortality reported in these psychiatric patients would be attributable in part to diseases in which Epstein-Barr virus is implicated or suspected as a cause.

Autoimmune Diseases↗
PubMed1989

Effect of dose and route of administration of ACTH1-24 on plasma cortisol concentrations in ewes.

Doses of 0.005-1.0 mg of ACTH1-24 given intravenously, intramuscularly or as an intramuscular depot injection caused increases in cortisol concentrations within 15 min in the plasma of ewes. There was, however, considerable animal-to-animal variation in maximum concentrations achieved. A curvilinear dose-response relationship to ACTH1-24 was obtained which was similar for each route of administration when expressed in terms of maximum cortisol concentrations. However, for a given dose, more prolonged release of cortisol occurred after i.m. injection compared to i.v., with maximum concentrations occurring 6 h after the depot formulation injection. Five repeated daily doses of 1.0 mg depot ACTH1-24 resulted in no diminution of cortisol response indicating considerable synthesizing capacity of the adrenals in clinically normal ewes. Comparison of cortisol concentrations after an acute stressor (shearing) suggests that doses of ACTH1-24 greater than 0.25 mg are excessive for simulation of stress-induced adrenal activity.

Animals↗
PubMed1989

Effect of PGI-2 on uterine activity in vivo in non-pregnant ovariectomized goats (Capra hircus).

Jugular administration of 200 micrograms PGI-2 salt significantly reduced spontaneous uterine activity in ovariectomized, oestrogen-primed goats; the effect was acute and persisted for about 3 h. Peripheral plasma concentrations of 6-keto-PGF-1 alpha, the stable metabolite of PGI-2, decreased to 50% of initial values after 30 min; but at the start of uterine recovery were in excess of 2 ng.ml-1. Uterine reactivity to both oxytocin and PGF-2 alpha after PGI-2 administration was unaffected.

Animals↗
PubMed1988

A preliminary note on the transient polymorphic oxidation of sparteine in the Ngawbé Guaymí Amerindians: a case of genetic divergence with tentative phylogenetic time frame for the pathway.

The oxidation of sparteine was studied in a total of 121 Ngawbé Guaymí volunteers in Panama, 97 of whom were unrelated. When presented in a frequency histogram, the results of the log10 of the metabolic ratios (LMR) indicated the existence of two modes, the largest of which exhibited a normal distribution (alpha = 0.05; chi 2 = 5.46). A preliminary assignment of an antimode for this population sample is proposed, located within the region of LMR 0.65 to 0.85 vs LMR of 1.3 for white subjects, and results in five poor metabolizers (PMs) (5.2%). This is in contrast to the absence of PMs (0/210) we have reported for the Cuna Amerindians. The microevolution of the sparteine route, corresponding to a tenfold change in the frequency of PMs, is likely to have occurred within their genetic divergence time. These observations of the divergence of a metabolic route of therapeutic importance and the proposal of a time frame for its microevolution constitute the first cases in the literature.

Adolescent↗
PubMed1988

Age-specific prevalence of Epstein-Barr virus antibodies in adult patients with affective disorders.

It has been suggested that prior Epstein-Barr virus (EBV) infection is a necessary condition for the development of affective disorders. To address this issue, the authors performed serologic screening for the presence of EBV antibodies in 60 adult patients seen at an affective disorders investigational unit. Six patients with clinically significant mood disorders, all aged 32 years or younger, had no detectable EBV antibodies. The authors conclude that the onset of clinical mood disorders can occur before primary EBV infection; thus, EBV infection is not a necessary condition for the development of mood disorders.

Adolescent↗
PubMed1988

A possible role for testosterone during luteolysis in the ewe.

Increased peripheral plasma concentrations of testosterone were detected at the commencement of luteolysis and at oestrus in sheep. Daily subcutaneous administration of spironolactone (10 mg kg-1) between days 10 and 16 of the oestrous cycle suppressed testosterone secretion and delayed luteolysis and oestrus. In pregnant ewes no increases in testosterone concentrations occurred between days 10 to 16 after mating and luteal regression, monitored by peripheral progesterone concentrations, was inhibited. It is suggested that aromatisation of testosterone to oestrogens is needed for luteolysis in sheep.

Animals↗
PubMed1985

Elevated 3,4-dihydroxyphenylethyleneglycol (DHPG) excretion in dexamethasone resistant depressed patients.

Urinary and plasma DHPG and MHPG were estimated in patients with MADD and showing DST non-suppression as compared to those with normal suppression. Day and night 12h urine collections and morning plasma samples were analyzed by GC-MS for total MHPG and DHPG and free MHPG levels. Urinary DHPG excretion was significantly elevated in DST non-suppressors compared to suppressors, but no differences were found in urinary MHPG or plasma glycol levels. Elevated DHPG excretion in DST non-suppressors suggests that increased peripheral sympathetic NE activity occurs in association with dexamethasone resistance in MADD.

Adult↗
PubMed1985

Suppression of prostaglandin F-2 alpha release and delay of luteolysis after active immunization against oxytocin in the goat.

Active immunization against oxytocin significantly prolonged the oestrous cycle in 3 out of 4 goats; the mean (+/- s.e.m.) cycle length was 29.1 +/- 1.7 days (n = 12) compared to 19.4 +/- 0.6 days (n = 9) in control animals. During Days 10-21 of the cycle in the 3 responsive goats, peripheral plasma concentrations of progesterone and oxytocin were steady and those of 13,14-dihydro-15-keto-prostaglandin F-2 alpha were very low (50-100 pg X ml-1) with no marked pulsatile activity. The major effect of immunization would appear to be suppression of the synthesis of the uterine luteolysin PGF-2 alpha, thus confirming that endogenous oxytocin has a facilitatory role in luteolysis via prostaglandin production.

Animals↗
PubMed1985

Effect of PGF2 alpha administration on the release of endogenous PGF2 alpha and oxytocin in indomethacin-treated goats.

Repeated intramuscular injection of 1 mg prostaglandin F2 alpha (PGF2 alpha) during the luteal phase of the oestrous cycle of the goat hastened luteolysis and resulted in rapid increases in jugular concentrations of 13,14-dihydro-15-keto PGF2 alpha (PGFM), the primary metabolite of PGF2 alpha, and of oxytocin; similar injections of PGF2 alpha in indomethacin-treated goats had a reduced effect on PGFM and oxytocin concentrations, and failed to induce luteolysis. The same injections of PGF2 alpha were without effect on PGFM and oxytocin concentrations in ovariectomised goats. The results suggest that exogenous PGF2 alpha, or endogenous PGF2 alpha released at luteolysis, may induce the release of ovarian oxytocin in the goat.

Animals↗