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Biomedical subjects

C E Gray

Publications and source records attributed to C E Gray.

At least 19 recordsLinked to original sources

Possible upregulation of hypothalamic 5-hydroxytryptamine receptors in patients with postviral fatigue syndrome.

OBJECTIVE: To study the dynamic function of hypothalamic 5-hydroxytryptamine receptors in patients with postviral fatigue syndrome. DESIGN: Prospective comparison of patients with postviral fatigue syndrome with two control groups. SETTING: Department of neurology, University of Glasgow, Southern General Hospital; department of psychiatry, St James's Hospital, Dublin. SUBJECTS: 15 patients with postviral fatigue syndrome, 13 age and sex matched healthy subjects, and 13 patients with primary depression. MAIN OUTCOME MEASURES: Serum prolactin concentrations before and one, two, and three hours after administration of buspirone. RESULTS: Because of the effects of sex hormones on prolactin secretion data for men and women were analysed separately. There was no significant difference in baseline prolactin concentrations between patients with postviral fatigue syndrome and healthy subjects or those with primary depression. However, the percentage difference between peak and baseline values was significantly higher in patients with postviral fatigue syndrome than the control groups (one way analysis of variance: women, p = 0.003; men, p = 0.004). CONCLUSIONS: The results suggest upregulation of hypothalamic 5-hydroxytryptamine receptors in patients with postviral fatigue syndrome but not in those with primary depression. The buspirone challenge test may therefore be useful in distinguishing these two conditions. Larger studies are required to explore the potential value of drugs acting on central 5-hydroxytryptamine receptors in the treatment of patients with the postviral fatigue syndrome.

Adult

Magnetic resonance findings in sarcoidosis of the thorax.

Fifteen patients with sarcoidosis underwent thoracic MRI examinations. The T2 signal intensity of lymphadenopathy varied, with no characteristic pattern noted. Three of four patients with bright lymph nodes on T2 images had stage I sarcoidosis, but low intensity nodes were also seen in stage I patients. Coronal images were complementary to axial images and better depicted subcarinal adenopathy. MRI does not distinguish the lymphadenopathy of sarcoidosis from other entities, but is useful for defining the anatomic extent of disease and differentiating pulmonary artery enlargement from adenopathy.

Adult

The effects of systemic intraoperative hypothermia on the acute-phase and endocrine response to cardiac surgery.

To determine the ability of intraoperative hypothermia to modify changes in the plasma protein component of the acute-phase response (APR) and the plasma hormone component of the endocrine response (ER) to surgical injury, 20 patients undergoing coronary artery surgery were randomised to an intraoperative blood temperature of 28 degrees C or 20 degrees C during cardiopulmonary bypass (CPB). Serial measurements of pack-cell-volume corrected concentrations (PCVCC) of five plasma proteins (albumin, prealbumin, transferrin, caeruloplasmin, ferritin) and six plasma hormones (adrenaline, noradrenaline, cortisol, triiodothyronine, thyroxine, and thyroid-stimulating hormone) were obtained twice preoperatively, seven times during surgery, six times in the 24 hours following surgery, and a further four times until the seventh postoperative day. A more profound level of intraoperative hypothermia significantly reduced the plasma adrenaline response to CPB but not the other components of the ER or APR.

Acute-Phase Reaction

Pancreatic and pituitary hormonal responses to insulin-induced hypoglycaemia during muscarinic cholinergic blockade in man.

To investigate the role of muscarinic cholinergic mechanisms in mediating the pancreatic and pituitary hormonal responses to hypoglycaemia, six normal subjects were studied during acute insulin-induced hypoglycaemia under control conditions, and during blockade with intravenous atropine. During atropine blockade the response of pancreatic polypeptide was suppressed while the maximum response of plasma glucagon was significantly higher. The increment in plasma vasopressin was also increased significantly during cholinergic blockade. During blockade with atropine the responses of plasma prolactin was reduced, with a slight but significant reduction in the growth hormone response, and although a similar maximum response of plasma ACTH was achieved, this rise was delayed. These results implicate involvement of a cholinergic muscarinic inhibitory and stimulatory mechanisms in regulating the responses of pancreatic and pituitary hormones to hypoglycaemia.

Adrenocorticotropic Hormone

Beta endorphin release in patients after spontaneous and provoked acute myocardial ischaemia.

BACKGROUND: In animal models of circulatory shock and heart failure concentrations of the endogenous opioid peptide beta endorphin are raised and opioid receptor blockade improves haemodynamic variables and survival. This study was performed to identify whether acute myocardial ischaemia provokes the release of beta endorphin in humans. METHODS: Observational study in a university cardiology centre. Serial measurements of beta endorphin made by specific radioimmunoassay were correlated with other clinical and neuroendocrine variables that were measured prospectively. Fifty five patients with acute myocardial ischaemia and 26 patients undergoing elective coronary angioplasty of the left anterior descending coronary artery were studied. RESULTS: beta endorphin concentrations were raised above the upper limit of normal in 31/42 (74%) patients with confirmed myocardial infarction, 3/13 (23%) patients with unstable angina, and 10/24 (42%) patients after coronary angioplasty. There was no evidence of myocardial release of beta endorphin. There were significant positive correlations between beta endorphin and the concentrations of adrenocorticotrophic hormone, cortisol, and arginine vasopressin. In patients with acute myocardial ischaemia there was a significant positive correlation between the peak concentrations of creatine kinase and beta endorphin but no correlation with visual analogue scores of the intensity of chest pain. The highest beta endorphin concentrations were seen in patients whose clinical course was complicated by the development of heart failure. CONCLUSIONS: beta endorphin release is a component of the neuroendocrine activation associated with myocardial ischaemia/infarction.

Acute Disease

Reversible menopause induced by the GnRH analogue buserelin: effects on lipoprotein metabolism.

GnRH agonists can induce a reversible pharmacological menopause and can be used to treat endometriosis, a fairly common gynaecological problem which responds well to oestrogen deprivation. Premature menopause is associated with adverse lipid changes and an increased risk of coronary heart disease. Therefore we set out to investigate changes in lipoprotein metabolism in a group of premenopausal women being treated with the GnRH analogue buserelin for active endometriosis. We monitored lipoprotein levels, high density lipoprotein subfractions and apolipoproteins AI, AII and B during a 12-month course of treatment and for 6 months afterwards. Treatment caused a sustained increase in HDL3 cholesterol levels and a small increase in low density lipoprotein cholesterol, which was significant at the six-month visit only. Apolipoprotein B levels rose significantly and there were marginal increases in apolipoproteins AI and AII. All changes and trends were reversed after cessation of treatment. We conclude that the treatment did not profoundly affect lipoprotein metabolism, neither LDL nor HDL cholesterol, the established important risk markers for coronary heart disease appreciably altered.

Adult

Effect of alpha-adrenergic blockade on pituitary hormonal responses to insulin-induced hypoglycemia in humans.

Arginine vasopressin, oxytocin and ACTH are released from the pituitary gland in response to acute hypoglycemia. To investigate the role of alpha-adrenergic mechanisms in mediating this response, 6 non-diabetic subjects were studied during hypoglycemia induced by 0.15 IU/kg i.v. insulin under control conditions, and during non-selective alpha-adrenergic blockade with phentolamine. In the control study plasma arginine vasopressin rose from 1.6 +/- 0.8 pmol/l (mean +/- SEM) basally to a maximum of 2.5 +/- 0.8 pmol/l following hypoglycemia (p less than 0.05). An exaggerated response was found during phentolamine blockade, with a maximum plasma vasopressin of 11.5 +/- 0.4 pmol/l (by analysis of variance, p less than 0.05). The plasma oxytocin response to hypoglycemia was similarly increased during phentolamine compared to control. Plasma growth hormone rose to 94 +/- 19 mU/l, and during blockade with phentolamine the response was significantly reduced reaching a peak of 34 +/- 7 mU/l (by analysis of variance, p less than 0.05). ACTH and prolactin both increased in response to hypoglycemia, but the increases were not affected by phentolamine. An alpha-adrenergic mechanism appears to inhibit the release of arginine vasopressin and oxytocin in response to hypoglycemia, but does not appear to affect the secretion of ACTH.

Adrenergic alpha-Antagonists

A comparison of calcium pentagastrin and TRH tests in screening for medullary carcinoma of the thyroid in MEN IIA.

Intravenous injections of calcium gluconate and pentagastrin (CPG) or TRH were compared as secretagogues for calcitonin (CT) in screening for medullary thyroid carcinoma (MTC) in multiple endocrine neoplasia type IIA (MEN IIA). Administration of CPG resulted in a prompt increase in plasma CT in all five patients with MTC studied, one of whom had a normal baseline value (peak 412-371,000 ng/l, 636-4847% above basal). TRH produced a rise in plasma CT levels only in MTC patients with elevated basal values; the magnitude of increase was less than that observed with CPG (peak 168-17,200 ng/l, 113-180% above basal). CT levels did not rise above 300 ng/l with either test in four unaffected first-degree relatives of MEN IIA patients, three subjects with sporadic unilateral phaeochromocytomas and five controls with essential hypertension. CPG remains the CT secretagogue of choice in screening for MTC in MEN II A.

Adult

The incidence of clinical thyroid dysfunction in an unselected group of pregnant and post partum women.

This study has examined the incidence of thyroid dysfunction during pregnancy and up to six months post partum in 65 women attending an antenatal clinic in the West of Scotland. Five were found to be positive for thyroid antibodies at presentation and in these the antibody titre fluctuated during pregnancy and in the post partum period. One patient developed thyroglobulin antibodies post partum. Mean total T3 and total T4 levels rose during pregnancy but had normalised by six weeks post partum. The changes in FT4 and TBG levels observed during pregnancy did not normalise until after six weeks post partum. Only one patient developed any biochemical evidence of thyrotoxicosis post partum and this was not found to be associated with the presence of thyroid antibodies. No patient showed any evidence of hypothyroidism.

Adult

ACTH-induced adrenal hemorrhage: a complication of therapy masquerading as an acute abdomen.

Four patients developed adrenal hemorrhage during treatment with intravenous adrenocorticotropic hormone (ACTH) for severe inflammatory bowel disease (IBD). This complication presented suddenly with upper abdominal and flank pain mimicking an acute surgical abdomen. In each patient the symptoms of the underlying bowel disease had subsided under the ACTH therapy. In our first patient the diagnosis was not made until laparotomy, but in the subsequent three patients the diagnosis was suspected by the strikingly similar clinical presentation. In each of these three latter patients the diagnosis was confirmed by sonography or computed tomography (CT) scan, and surgery was avoided. All four of our patients are doing well at 1-58 months of follow-up. Signs of adrenal insufficiency occurred only in the one of our four patients, and in those six of 11 previously reported patients, who had bilateral adrenal hemorrhage. ACTH-induced adrenal hemorrhage requires stopping ACTH and maintaining corticosteroid support. The diagnosis of adrenal hemorrhage should be considered in the patient treated with ACTH who develops unexplained acute abdominal or flank pain. Failure to recognize this complication of ACTH therapy can lead to unnecessary surgery or the dangerous continuation of the offending agent.

Abdomen, Acute

Recovery of hypothalamic-pituitary-adrenal function after intermittent high-dose prednisolone and cytotoxic chemotherapy.

Hypothalamic/pituitary and adrenal (HPA) function was assessed in ten patients who received intermittent high-dose prednisolone and cytotoxic chemotherapy for 5-40 months. Standard insulin hypoglycaemia (IHT), thyrotrophin-releasing hormone and tetracosactrin tests were performed 36 hr after the last dose of prednisolone and subsequently 10 days--52 weeks after completion of all chemotherapy. In the first tests there was evidence of impaired hypothalamic-pituitary function judged by peak adrenocorticotrophic hormone (ACTH), growth hormone (GH) and thyrotrophin (TSH) responses, and corresponding plasma corticosteroid responses were sub-normal in five patients. In the final IHTs, seven patients had persistently subnormal ACTH responses but all the corresponding plasma corticosteroid responses returned to normal. Mean peak corticosteroid responses to insulin and tetracosactrin and peak GH responses were significantly greater than in the first tests. Such chemotherapy regimens may have prolonged effects on hypothalamic/pituitary function but the demonstration of normal corticosteroid responses to hypoglycaemia and tetracosactrin indicates that these patients' stress responses will be normal as early as 10 days after treatment is stopped.

Adrenal Cortex Hormones

Hypothalamic/pituitary/adrenal function in patients treated with intermittent high-dose prednisolone and cytotoxic chemotherapy.

Hypothalamic/pituitary/adrenal (H.P.A.) function was assessed in ten patients receiving intermittent high-dose prednisolone and cytotoxic chemotherapy for myeloma of lymphoma in order to predict their possible requirement for additional steroid therapy between and at the end of treatment courses. Standard insulin hypoglycaemia tests performed 36 hours after the last dose of prednisolone often demonstrated impairment of corticotrophin (adrenocorticotrophic hormone, A.C.T.H.) and growth-hormone responses, indicating hypothalamic/pituitary suppression; plasma-corticosteroid responses to endogenous A.C.T.H. and tetracosactrin were abnormal in two patients, indicating secondary adrenal suppression. Such hypothalamic/pituitary and adrenal suppression may make these patients susceptible to acute adrenal insufficiency in times of stress. H.P.A. function should be fully assessed on completion of chemotherapy.

Adrenal Cortex Hormones

The renal handling of insulin and thyroid hormones in normal man.

1. The renal extraction of insulin and thyroid hormones T3 and T4 was studied in man by right renal vein catheterization. 2. The mean renal extraction of insulin was 0-46, suggesting that the right renal vein should be utilized in comparable studies. 3. No renal extraction of thyroid hormones was detected.

Adult

Hypoaldosteronism in three sibs due to 18-dehydrogenase deficiency.

Three sibs all presented in the early neonatal period with a salt-losing syndrome. The salt-losing form of congenital adrenal hyperplasia was diagnosed and appropriate treatment with glucocorticosteroids, mineralocorticosteroids, and additional dietary salt started. Although early life was maintained with difficulty, with age all 3 children required decreasing amounts of replacement steroids to maintain normal plasma electrolyte balance. They were reinvestigated at the ages of 15 years and 8 years (twins), when cortisol synthesis and metabolism proved normal, but aldosterone synthesis was blocked by deficiency of 18-dehydrogenase. Rational treatment of these cases of a salt-losing syndrome in which aldosterone synthesis alone is blocked due to lack of the enzyme 18-dehydrogenase requires the administration of a mineralocorticosteroid drug only. Since deoxycorticosterone (acetate or pivalate) requires intramuscular administration, as life-long therapy oral fludrocortisone is preferable. Although fludrocortisone has glucocorticoid activity, the "hydrocortisone equivalent" effect of the small dosage used was unlikely to inhibit either pituitary corticotrophin or growth hormone production.

Adolescent