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Biomedical subjects

B Sheridan

Publications and source records attributed to B Sheridan.

At least 109 records · Page 6Linked to original sources
PubMed1987

Three months energy restricted diet does not reduce peripheral insulin resistance in newly diagnosed non insulin dependent diabetics.

Sixteen newly diagnosed non insulin dependent diabetic patients were treated for 3 months with an individual energy restricted diet. The effect on weight, hyperglycaemia and insulin response to oral glucose was measured in all subjects, and in 7, peripheral insulin resistance was estimated using a hyperinsulinaemic glucose clamp at two insulin infusion rates (40 and 400 mU m-2 X min-1). After diet, fasting plasma glucose fell from 12.0 +/- 0.7 mmol/l (mean +/- SEM) to 7.4 +/- 0.5 mmol/l (P less than 0.001) and weight fell from 92.9 +/- 4.2 kg to 85.0 +/- 3.1 kg (P less than 0.001). The plasma insulin response to oral glucose was unchanged after diet therapy. Insulin induced glucose disposal (M) was also unaffected by diet at insulin infusion rates of 40 mU m-2 X min-1 (12.5 +/- 1.5 mumol X kg-1 X min-1 vs 15.7 +/- 1.6 mumol X kg-1 X min-1) and 400 mU m-2 X min-1 (49.5 +/- 2.7 mumol X kg-1 X min-1 vs 55.1 +/- 2.5 mumol X kg-1 X min-1). These results show that 3 months reduction of energy consumption with weight loss in newly diagnosed non insulin dependent diabetics improves B-cell responsiveness to glucose but has no effect on liver glucose output or on peripheral insulin action.

Adult↗
PubMed1987

Normal growth and pubertal development during bromocriptine treatment for a prolactin-secreting pituitary macroadenoma.

An 11-year-old male presented with a 2-year history of headache and lethargy. Serum PRL was elevated at 14,000 mU/l and computerized tomography showed a pituitary macroadenoma. Visual fields and fundi were normal and the testes showed early pubertal changes. There was normal responsiveness of serum cortisol but absence of GH response to hypoglycaemia. After bromocriptine therapy for 4 months serum PRL had fallen to 90 mU/l and the tumour was not visible on repeat computerized tomography. After 7 months treatment, repeat pituitary function testing showed restoration of GH response to hypoglycaemia. Treatment with bromocriptine was continued and there was spontaneous progression of normal puberty; the serum testosterone continued to rise, and height maintained the 50th centile. Bromocriptine therapy should be considered as initial therapy in the management of prolactinomas in prepubertal patients.

Adenoma↗
PubMed1987

Clinical experience with ketoconazole as a therapy for patients with Cushing's syndrome.

Six consecutive patients with Cushing's disease were treated with the broad spectrum antifungal drug ketoconazole. Urinary cortisol levels rapidly fell to within the normal range in five of the six patients. Acute hypoadrenalism occurred in one patient, and nausea and pyrexia in three. Our experience with hepatotoxicity was different from that reported by others in that reversible hepatotoxicity was demonstrated in three patients within 7 to 12 days of treatment. Further work is required before ketoconazole can be recommended as a standard primary therapy for patients with Cushing's syndrome. Continuing vigilance for both hypoadrenalism and hepatotoxicity is essential in any patient being treated with this drug either for hypercortisolism or for other reasons.

Adult↗
PubMed1987

Assays for follicle stimulating hormone and luteinising hormone: guidelines for the provision of a clinical biochemistry service.

The measurement of serum follicle stimulating hormone (FSH) and luteinising hormone (LH), together with the appropriate sex steroid, is of great value in the investigation of delayed and precocious puberty, hypogonadism, subfertility, polycystic ovarian disease and hypothalamic-pituitary disorders. Dynamic function testing of the hypothalamic-pituitary-gonadal axis should be restricted to a few defined situations. Sequential LH measurements, either in serum or in urine, may be used to time ovulation during artificial insemination or in vitro fertilisation programmes. No special precautions are necessary when sampling for FSH and LH measurement; serum is preferred to plasma and should be stored frozen before assay. Aliquots of timed urine specimens of known volume should be stored frozen without preservative. Gonadotrophin results should be available within 2-3 weeks; laboratories unable to meet this schedule are advised to send their samples to a Regional Centre for assay. Reagents for the radioimmunoassay of FSH and LH are readily available, and standard techniques have been developed for their use. Laboratories using 'in-house' methods should pay particular attention to the matrix used for preparing standard solutions, the purification of radioligands and the optimisation of the separation system. Low cost matched reagents of proven performance are available in kit form from the Chelsea Hospital for Women; several commercial kits are also available, although few are widely used in the UK. The overall performance of laboratories in the UK External Quality Assessment Scheme (EQAS) for FSH and LH has remained steady for several years. Of the 130 participants, only about 15% in each scheme have 'good' performance (cumulative bias less than 10%, plus cumulative variability of bias less than 10%), whilst a similar proportion have 'unacceptable' performance (cumulative bias greater than 20% and/or cumulative variability of bias greater than 25%). The remaining 70% of laboratories have 'adequate' performance but are at risk of producing results that are clinically misleading. Within any one method group, the performance of FSH and LH assays are closely related. Optimal assay performance depends upon sensible laboratory management to ensure skilled operators, a regular programme of reagent/kit renewal, comprehensive internal and external quality assessment, and attention to detail in all aspects of gonadotrophin assay. The working range of each individual assay should be defined and no absolute result reported from outside this range.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

Short term administration of gonadotropin-releasing hormone analog to a patient with a testosterone-secreting ovarian tumor.

A GnRH superagonist, buserelin, was administered for 16 days to a postmenopausal woman with a testosterone-secreting ovarian tumor. Serum gonadotropin levels decreased by more than 70%, and serum testosterone fell by more than 50%. This short term study demonstrates that in these uncommon tumors androgen secretion is gonadotropin sensitive, and suggests that GnRH analogs may have therapeutic value in such patients.

Administration, Intranasal↗
PubMed1987

Pure FSH induces ovulation in polycystic ovary syndrome despite rising androgen levels.

Five patients with carefully defined polycystic ovarian disease (PCOS) were treated with pure follicle stimulating hormone (FSH) to induce ovulation. Serum levels of androstenedione and testosterone were measured daily and noted to rise dramatically, reaching a maximum at the time of ovulation. However, despite the rise in androgens, ovulation occurred in each case and three patients conceived. Contrary to the traditional concept, it is concluded that elevated androgen levels in patients with PCOS do not interfere with ovulation induction using pure FSH.

Androgens↗
PubMed1986

Familial hypocalciuric hypercalcaemia as a differential diagnosis of hyperparathyroidism: studies in a large kindred and a review of surgical experience in the condition.

We have studied 46 members of a large kindred with familial hypocalciuric hypercalcaemia (FHH) after a neck exploration failed to cure hypercalcaemia in an asymptomatic patient. Serum calcium, serum phosphate, plasma parathormone and vitamin D metabolites do not distinguish affected members from patients with hyperparathyroidism. Because of the continuing debate as to whether or not FHH is a variant of, or distinct from, hyperparathyroidism, we have carried out a review of surgical experience with subtotal parathyroidectomy in hyperparathyroidism secondary to parathyroid hyperplasia and in FHH. Whereas the procedure is successful in 90 per cent of the former cases only one case of FHH has been cured by it. This provides evidence for the two conditions being aetiologically distinct. Before patients with asymptomatic hypercalcaemia are referred for parathyroid surgery the calcium:creatinine clearance ratio should be measured using a 2 h urine sample collected after an overnight fast and a fasting blood sample. If this ratio is less than 0.01 then screening of first degree relations should be undertaken before any parathyroid surgery is performed. Unnecessary surgery can therefore be avoided.

Adult↗
PubMed1986

Human leukocyte function-associated antigens on lympho-hemopoietic precursor cells.

The expression of human leukocyte function-associated antigens (HLFA, equivalents of murine LFA-1) was studied on early lympho-hemopoietic cells in infant thymus and normal bone marrow by double immunofluorescence methods, cell sorting and colony-forming assays. Monoclonal antibodies MHM-24 recognizing the alpha chain (180 kDa) and 60.3 and 60.1 identifying the beta chain (95 kDa) were used. The vast majority of thymocytes including large terminal deoxynucleotidyl transferase (TdT)-positive blast cells are HLFA positive. On the other hand, most B cell precursors in the bone marrow, identified by the expression of nuclear TdT, do not show surface HLFA which appears at the pre-B cell stage (cytoplasmic mu positive, surface Ig negative). Cell sorting experiments revealed an enrichment of early myeloid cells (myeloblasts and colony-forming unit cells) in the HLFA-negative fraction. Erythroid cells appeared to be completely negative from the burst-forming unit erythrocyte stage onwards. Anti-HLFA-antibodies, capable of blocking T cell and natural killer function, may have therapeutic potential without interfering with precursor cell development in man.

Antibodies, Monoclonal↗
PubMed1986

One month's insulin treatment of type II diabetes: the early and medium-term effects following insulin withdrawal.

In order to see if subcutaneous insulin treatment of type II diabetes might produce lasting physiologic changes, ten patients received one month's insulin treatment under strict dietary supervision. When compared to the pretreatment period, 48 hours after discontinuing insulin treatment fasting plasma glucose had fallen (P = 0.005), fasting serum insulin had risen (P = 0.005), and fasting hepatic glucose production measured by 3H-3-glucose turnover had fallen (P = 0.008). The metabolic clearance rate of glucose measured with the glucose clamp rose significantly after treatment at insulin infusion rates of 40 mU m-2 min-1 (P = 0.015) and 400 mU m-2 min-1 (P = 0.012). The serum insulin and C-peptide responses to oral glucose improved after the treatment in association with the improvement in glucose tolerance, but the plasma glucose response was unchanged. Six other type II diabetic patients who received only dietary supervision did not show significant changes in these variables. Six weeks after discontinuing insulin, the patients' fasting hepatic glucose production was still reduced compared to pretreatment (P = 0.028) and insulin action was still improved at both the lower (P = 0.028) and the higher (P = 0.028) insulin infusion rates, but the fasting plasma glucose and insulin and C-peptide responses to oral glucose had returned to pretreatment values. The improvement in glucose tolerance and beta-cell function induced by insulin treatment seems to be of more limited duration than the improvements in basal hepatic glucose production and in insulin action.

Aged↗
PubMed1986

Comparison of cod-liver oil and aspirin-dipyridamole for the prevention of intimal hyperplasia in autologous vein grafts.

The combination of aspirin and dipyridamole is currently used to prevent intimal hyperplasia and to improve long-term vein graft patency following myocardial revascularization. Preliminary studies indicate that cod-liver oil, rich in eicosapentaenoic acid, an unsaturated fatty acid, may also be effective in the prevention of intimal hyperplasia. Twenty-four mongrel dogs were used to compare the effectiveness of aspirin-dipyridamole and cod-liver oil on vein graft intimal hyperplasia following arterial bypass. Forty-eight segments of undistended autologous external jugular vein were interposed between bilaterally divided femoral arteries. All animals received a 2% cholesterol diet for 1 week before and 6 weeks after operation. Eight controls received the diet alone. Eight other animals received dipyridamole (2.5 mg per kilogram of body weight) two days before operation and dipyridamole (2.5 mg/kg) and aspirin (30 mg/kg) daily for 6 weeks after operation. Another 8 animals received cod-liver oil containing 1.8 gm of eicosapentaenoic acid daily 1 week before and for 6 weeks following operation. Serum cholesterol increased similarly in all groups; it rose from 4.5 +/- 0.2 mm/L to 8.3 +/- 0.8 mm/L in the controls, to 7.2 +/- 0.5 mm/L in the aspirin-dipyridamole group, and to 7.1 +/- 0.5 mm/L in the cod-liver oil group (p less than 0.01). Prothrombin time, partial thromoboplastin time, total platelet counts, and bleeding times were unchanged. Intimal hyperplasia was measured at 6 weeks with a Zeiss computerized microscope; 376 +/- 25 measurements were made from each graft. The intima increased from 4.5 +/- 0.2 to 83 +/- 10 micron in the control dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Inappropriate thyrotrophin secretion, increased dopaminergic tone and preservation of the diurnal rhythm in serum TSH.

A patient presented with mild hyperthyroidism, elevated serum T4 and T3, and an inappropriately raised serum thyrotrophin (TSH). There was no evidence of pituitary tumour (alpha-subunit secretion and CT scan of the pituitary were normal). The TSH response to TRH was greater than normal. The elevated TSH was suppressed by oral triiodothyronine (100 micrograms daily for 10 d). The normal diurnal variation of TSH was preserved. Intravenous injection of the dopamine receptor blocking agent domperidone led to a greater than normal elevation in TSH (maximum increments 18-20 mU/l). This increased dopaminergic tone was similar in studies carried out in the morning and late evening. The dopamine agonist bromocriptine (2.5 mg twice daily) failed to suppress serum TSH either acutely or over 6 weeks. The circadian rhythm was unaltered by this treatment. Basal serum prolactin levels were normal, and responded appropriately to TRH, domperidone and bromocriptine. These observations indicate that dopamine does not control the diurnal variation of TSH in nontumoral TSH-mediated hyperthyroidism. The increased dopaminergic tone demonstrated may be secondary to the primary failure of pituitary-thyroid feedback in the condition.

Adult↗
PubMed1986

Studies of hypothalamic pituitary structure and function in patients previously treated with bilateral adrenalectomy alone for Cushing's disease.

A controversy still exists in regard to hypothalamic pituitary function long-term after cure of hypercortisolism due to Cushing's disease. In an attempt to resolve this controversy, we have studied 15 patients, treated at least 6 years previously, by bilateral adrenalectomy. None of these patients had had pituitary-directed therapy. The maximum increment response of serum TSH in response to TRH was greater than 5 mU/l in 13 of the 15. Serum PRL response to TRH, GH response to insulin-induced hypoglycaemia, gonadotrophin responses to LHRH and nocturnal PRL secretion were normal in all patients studied. When nocturnal GH secretion was corrected for age, body mass index and menopausal status it was definitely abnormal in only two patients. The mean nocturnal GH secretion did not differ from that measured in a control group of Addisonian patients. The series of patients also did not differ significantly from the Addisonian patients in relation to the pattern of changes in plasma ACTH, over 24 h after an 0800 h oral dose of hydrocortisone. There was a significant rise in plasma ACTH between 2200 h and 0600 h in both groups of patients. The plasma ACTH concentrations were significantly higher in post-adrenalectomy patients. Hypothalamic pituitary function is normal in the long-term in the majority of patients treated by bilateral adrenalectomy for Cushing's disease.

Adrenalectomy↗
PubMed1986

Bromocriptine reduces growth hormone in acromegaly.

We assessed serum growth hormone (GH) levels in ten patients with acromegaly during a 24-hour profile and a 75-g oral glucose tolerance test (GTT). Serum GH levels were measured after five weeks of bromocriptine mesylate therapy, 20 mg daily (P1), after five weeks without bromocriptine mesylate therapy (P2), and again five weeks following restarting treatment with bromocriptine, 20 mg daily (P3). During the 24-hour profile, the following occurred: (1) mean serum GH level of the group was lower during P1 (20.5 mU/L) and P3 (20.8 mU/L) than P2 (49.6 mU/L); (2) in six individual patients during P1 and P3, there was a significant reduction in the mean serum GH value; and (3) a marked circadian variation in the serum GH value was present both with and without the drug therapy in five patients. During the GTT, the mean serum GH value was lower during P1 (18.4 mU/L) and P3 (16.7 mU/L) than P2 (43.3 mU/L), and in seven individual patients during P1 and P3, there was a significant reduction in the mean serum GH value. Overall, a clear reduction in serum GH values due to bromocriptine was demonstrated. In individual patients, serum GH values during a 24-hour profile and GTT gave similar indications of response.

Acromegaly↗
PubMed1985

Five cases of cyclical Cushing's syndrome.

Reported cases of cyclical Cushing's syndrome are rare. Of 14 successive patients with Cushing's syndrome nine collected sequential urine samples for the estimation of cortisol:creatinine ratio. Five had cyclical Cushing's syndrome while two had considerable variation in urinary cortisol excretion without a cyclical pattern being established. Two of the five patients with a cyclical syndrome had paradoxical responses to dexamethasone. In only one patient with a cyclical pattern did the cortisol:creatinine ratio fall after treatment with bromocriptine or cyproheptadine, or both. The high incidence of the cyclical form of Cushing's syndrome has important clinical implications. A high index of suspicion of the syndrome is required in patients with symptoms or signs of Cushing's syndrome but with normal cortisol values, in patients with fluctuating cortisol values, and in patients with anomalous responses to dexamethasone. Because of possible variations in steroidogenesis the results of drug studies in Cushing's syndrome must be interpreted cautiously.

Adrenocorticotropic Hormone↗
PubMed1985

Amiodarone-induced hypothyroidism. A common complication of prolonged therapy: a report of eight cases.

Amiodarone is a widely used antiarrhythmic drug, which contains 75 mg of iodide per 200 mg of active substance. Eight of our patients receiving long-term amiodarone therapy became hypothyroid. Seven of these patients had no previous history of thyroid dysfunction or goiter. Antithyroid antibodies were absent, and standard perchlorate discharge tests were positive in seven patients when hypothyroidism was diagnosed. In one patient, amiodarone therapy was withdrawn; over the next nine months, the hypothyroidism resolved, and results of the perchlorate discharge test reverted to normal. We conclude that amiodarone-induced hypothyroidism is similar to previously described iodide-induced hypothyroidism. It may develop in the absence of a previous history of thyroid disease, and all patients receiving long-term amiodarone therapy should therefore be regularly monitored for hypothyroidism.

Aged↗