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Biomedical subjects

B Sheridan

Publications and source records attributed to B Sheridan.

At least 127 records · Page 7Linked to original sources

Prolactin responses to thyrotrophin releasing hormone do not distinguish patients with isolated gonadotrophin deficiency from normals.

Prolactin secretion in response to TRH has been assessed in six patients with isolated gonadotrophin deficiency (IGD) and in eight normal controls. In all six subjects with IGD, serum oestradiol was below the detection limit of the method. There was no statistical difference between either the basal or maximum increment of serum prolactin between the two groups. Recent claims that prolactin responses to TRH distinguish constitutional delay of puberty from IGD have therefore not been supported.

Adult↗

Six year remission of ACTH-dependent Cushing's syndrome using bromocriptine.

A patient with ACTH-dependent Cushing's syndrome remained in clinical and biochemical remission six years after pituitary irradiation and while on bromocriptine therapy. When bromocriptine was discontinued urinary free cortisol values became elevated, and were not suppressed by dexamethasone. After reintroduction of the drug, remission was again obtained. It is concluded that bromocriptine is responsible for continuing longterm remission in this case. The possible use of bromocriptine as an adjunctive therapy in ACTH-dependent Cushing's syndrome is discussed.

Adrenocorticotropic Hormone↗

Cyclical Cushing's disease: two distinct rhythms in a patient with a basophil adenoma.

A 71-yr-old woman with clinical signs of Cushing's syndrome was studied continuously for an extended period after demonstration of a paradoxical response to dexamethasone. She proved to have a corticotroph cell adenoma of the pituitary which caused secretion of ACTH and cortisol in two distinct rhythms. One rhythm consisted of a period of 40 days of excess cortisol production, followed by a period of 60-70 days of normal production. During the period of excess cortisol production there was a second rhythm, consisting of peaks of cortisol production every 3-6 days with intervening troughs of normal cortisol production. Prolonged clinical remission followed transphenoidal surgery, but the pituitary still has the ability to provoke abnormal amounts of cortisol secretion, as occurred during a postoperative dexamethasone suppression test. The long duration of normal cortisol production phases in this patient demonstrates the difficulty in excluding Cushing's syndrome in patients with suggestive clinical symptoms but normal serum and urinary cortisol levels if these tests are measured for a single short phase of several days.

Adenoma, Basophil↗

Cod-liver oil in the prevention of intimal hyperplasia in autogenous vein grafts used for arterial bypass.

Cod-liver oil, rich in eicosapentaenoic acid, an unsaturated fatty acid, was administered to 14 mongrel dogs to determine if this acid would prevent platelet-mediated intimal hyperplasia. Twenty-eight 1 cm segments of undistended jugular vein were interposed between bilaterally divided femoral arteries. Seven control animals were fed a 2% cholesterol diet 1 week before and for 6 weeks after the operation. A further seven animals received cod-liver oil capsules containing 1.8 gm of eicosapentaenoic acid daily 1 week before and for 6 weeks after autogenous vein implantation, in addition to the lipid-supplemented diet. Baseline serum cholesterol was 4.6 +/- 0.4 mmol/L. The rise in serum cholesterol was similar in the two groups and increased to 7.4 +/- 0.6 mmol/L (control group) and to 6.8 +/- 0.2 mmol/L (eicosapentaenoic acid group) (p less than 0.001). Prothrombin time, partial thromboplastin time, bleeding time, and platelet counts were unchanged in the two groups. Vein grafts, harvested at 6 weeks, were fixed in formaldehyde. Mean intimal thickness was measured from multiple vein graft cross sections with a Zeiss computerized interactive image analyzing system. A mean of 140 +/- 11 measurements were computed from each graft. Marked intimal hyperplasia occurred in the control group and increased from 4.3 +/- 0.3 to 86.4 +/- 14 micron. In contrast, a high eicosapentaenoic acid diet inhibited intimal hyperplasia, with intimal thickness only increasing from 4.0 +/- 0.4 to 24.8 +/- 2.7 micron (p less than 0.001). These data indicate that eicosapentaenoic acid inhibits platelet-mediated intimal hyperplasia and suggest that cod-liver oil could be used to prevent intimal hyperplasia in vein grafts used for myocardial revascularization.

Animals↗

Serum cortisol concentrations during low dose dexamethasone suppression test to screen for Cushing's syndrome.

Forty four subjects (23 obese controls, 11 patients with possible Cushing's syndrome, and 10 patients with definite Cushing's syndrome) underwent low dose (0 X 5 mg every six hours for two days) dexamethasone suppression tests during which serum cortisol concentration at 0800 and excretion of urinary free cortisol over 24 hours were measured. Serum cortisol concentration fell to below 60 nmol/1 (2 X 2 micrograms/100 ml) in 31 subjects and remained above 250 nmol/1 (9 X 1 micrograms/100 ml) in the 13 others. Excretion of urinary free cortisol showed a similar response, falling to below 110 nmol (40 micrograms)/24 h in 31 and remaining above 180 nmol (65 micrograms)/24 h in the 13 others. There was complete concordance between the two variables in terms of the pattern of response. Serum cortisol concentration fell to below 60 nmol/1 (2 X 2 micrograms/100 ml) in at least 97% (31 of a possible 32) of subjects without Cushing's syndrome. On the other hand, a serum cortisol concentration of above 250 nmol/1 (9 X 1 micrograms/100 ml) after low dose dexamethasone gave a false positive diagnosis of Cushing's syndrome in at most only one of 13 patients (7 X 7%). Measurement of serum cortisol concentration during the low dose dexamethasone test is simpler than, and as accurate and reliable as, measurements of urinary steroids.

Adolescent↗

Contribution of isolated general practitioner maternity units.

A postal survey of isolated general practitioner maternity units in England and Wales showed that just under 4% of deliveries take place in them. Eight per cent of general practitioners are on the staffs, and in 87% of units midwives are integrated with the community midwifery service. Sixty two per cent of units have visiting consultant cover. Fifty seven per cent of patients are booked and delivered in the unit, 28% are booked and deliberately delivered elsewhere, 5% are transferred in the antenatal period, and 10% transferred as emergencies. The perinatal mortality rate for cases booked and delivered in the units is 1.1 per 1000. The number of emergency transfers was appreciably less for those units that were prepared to do their own operations. Thirty five per cent of these units are liable to be cut off in bad weather, and they will continue to fulfil an essential role in the midwifery services.

Delivery, Obstetric↗

Cushing's syndrome in pregnancy--treatment with metyrapone.

A 23-year-old female presented with severe Cushing's syndrome in the 23rd week of pregnancy. Investigations showed plasma cortisol 770 nmol/l (08.00 h) and 850 nmol/l (23.00 h); plasma ACTH was 10 ng/l (08.00 h) and 27 ng/l (23.00 h); urinary free cortisol excretion was 2460 nmol/24 h. Dexamethasone 2 mg 6-hourly for 48 h suppressed the 08.00 h plasma cortisol only to 680 nmol/l. Abdominal C.T. scan showed a right adrenal adenoma. The patient was treated with metyrapone and a good clinical improvement ensued. Plasma cortisol was reduced to 300-500 nmol/l. Depsite ultrasonographic evidence of normal fetal growth, urinary oestriol excretion was markedly deficient. Prior to the spontaneous onset of labour, there was a marked rise in plasma cortisol despite continuous metyrapone treatment. A normal female infant was born at 37 weeks' gestation. The maternal adrenal adenoma was subsequently removed. The deficiency of oestriol synthesis during the pregnancy may be explained by metyrapone-induced inhibition of C19-hydroxylation.

Adenoma↗

Sex hormone levels in younger male stroke survivors.

Increased plasma oestrogen levels have been reported in men with myocardial infarction. To establish whether similar findings occur in stroke, plasma oestradiol and testosterone levels were measured in 26 male survivors of stroke and 27 healthy male controls. There was no difference in oestradiol or testosterone levels between the two groups and the oestradiol : testosterone ratio was also identical. The result of this study does not support the suggestion that hyperoestrogenaemia is a risk factor for atherosclerosis in general.

Age Factors↗