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Biomedical subjects

A B Atkinson

Publications and source records attributed to A B Atkinson.

At least 127 records · Page 7Linked to original sources
PubMed1988

Natural history of pancreatic islet B-cell function in type 2 diabetes mellitus studied over six years by homeostasis model assessment.

Islet B-cell function and insulin sensitivity were estimated with the aid of a mathematical model from repeated fasting plasma glucose and insulin measurements over a 6 year period in 131 patients with type 2 diabetes mellitus who could be managed satisfactorily on dietary therapy alone. They presented between the ages of 40 and 69 years, and were studied before and after one year of treatment, and then at regular intervals from 12 until 72 months later. A method of averaging the individual trends by means of a linear model regression technique was used to assess the progression of their diabetes. Dietary management over the first 12 months resulted in weight loss from 118% to 106% average body weight, and improved insulin sensitivity from 26% to 40% of normal (p less than 0.001). From 12 to 72 months, the fasting plasma glucose rose at a mean rate of 0.23 mmol/l per year (p less than 0.001) despite a rate of weight loss of 0.2% average body weight per year (p less than 0.01). The estimated islet B-cell function, expressed as a percentage of normal, decreased significantly (p less than 0.05) at a rate of 1.5% per year, with no statistically significant change in insulin sensitivity. Extrapolation suggests the reduction in B-cell function predated the departure of fasting plasma glucose from the normal range.

Adult↗
PubMed1988

Renal artery stenosis in hypertensive diabetic patients.

The prevalence of secondary forms of hypertension in diabetes is unknown. One hundred and five of 465 patients randomly selected from a diabetic clinic population were found to be hypertensive. Hypertensive patients aged less than 70 years were screened for renal artery stenosis using intravenous digital subtraction angiography. Two angiograms were technically unsatisfactory. All 18 insulin-dependent patients successfully screened had normal renal arteriograms. Five of 24 non-insulin-dependent patients had unilateral renal artery stenosis but functional tests did not clearly suggest that renal artery stenosis was causing the hypertension in these cases. No patient was referred for surgery or angioplasty. We conclude that renal artery stenosis is common in hypertensive non-insulin-dependent diabetics but may not, in many cases, be the cause of the hypertension. The criteria for investigating diabetic hypertensives for renal artery stenosis should be no different from those used in the general hypertensive population.

Adult↗
PubMed1988

Conventional dose intravenous pulsatile GnRH therapy does not induce ovulation in polycystic ovarian disease.

The value of pulsatile GnRH therapy for induction of ovulation in patients with polycystic ovarian disease remains unclear. Intravenous pulsatile GnRH therapy was administered to a defined group of 5 patients with polycystic ovarian disease; all were infertile, had an LH:FSH ratio of greater than 2:1 on two or more occasions, and had multiple cysts on ovarian ultrasonography. All had failed to respond to clomiphene citrate. The 5 patients received increasing doses of GnRH (5-40 micrograms/pulse) continuously for up to 6 weeks. The response was evaluated by serial hormone levels and ovarian ultrasonography. During nine treatment periods no patient ovulated, and in only one did the LH:FSH ratio revert to normal. Four patients have subsequently had wedge resection of the ovaries and in each case the diagnosis of polycystic ovarian disease was confirmed. Pulsatile GnRH therapy was of no value in the management of this group of infertile patients with strictly defined polycystic ovarian disease.

Adult↗
PubMed1988

Increased pro-opiomelanocortin-derived peptide release in myotonic dystrophy.

The response of plasma immunoreactive (IR)-ACTH, IR-beta-endorphin (beta-END) and IR-cortisol to insulin-induced hypoglycaemia, an acute stimulus to the pituitary corticotrophs through the central nervous system, and to synthetic ovine corticotrophin-releasing hormone (CRH), a direct corticotroph stimulator, were studied in normal males and males with myotonic dystrophy. Myotonics had an increased IR-ACTH and IR-beta-END response to hypoglycaemia and an increased IR-ACTH response to CRH compared with normals. Plasma IR-cortisol response were not different in either group of subjects to both stimuli. This neuroendocrine abnormality in myotonic dystrophy may represent a manifestation of the purported specific cell membrane defect underlying the disease. This is the first report of an abnormality in proopiomelanocortin peptide release in myotonic dystrophy.

Adolescent↗
PubMed1987

Renal tuberculosis and accelerated hypertension: the use of renal vein renin sampling to predict the outcome after nephrectomy.

This case report records the rare presentation of accelerated hypertension secondary to long-standing renal tuberculosis and the subsequent beneficial response to surgery predicted by lateralisation of renin levels within the renal veins. The patient's hypertension proved difficult to control medically and he was therefore assessed for possible surgical management. Renin sampling revealed clear lateralisation within the renal veins indicating possible benefits from surgery. Nephro-ureterectomy was performed and, post-operatively, the patient's hypertension, while not completely resolved, was easily controlled with monotherapy. Patients with unilateral renal tuberculosis and hypertension which prove difficult to control should have measurement bilaterally of renal venous renin which may indicate potential benefits from surgery.

Humans↗
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

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↗
PubMed1986

Neuroendocrine tumors. A European view.

A center in Belfast, Northern Ireland, has established a register for tumors of the gastroenteropancreatic endocrine system. Carcinoid tumors occur most frequently. Of the non-carcinoid tumors, insulinomas, gastrinomas, and unknown types have the highest incidence, with other types being extremely rare. The potentially remediable nature of the tumors is stressed, and frequently a good quality of life can be experienced even in the presence of metastatic disease. The syndromes are probably underdiagnosed as they present with clinical features for which there are more common explanations, and appropriate diagnostic methods are therefore not used. The management of the syndromes is reviewed with particular emphasis on the treatment of patients with inoperable disease. Histamine (H2)-receptor antagonist therapy has made an impact in Zollinger-Ellison syndrome, and streptozotocin and somatostatin analogues can control tumor growth and endocrine syndromes, respectively.

Apudoma↗
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

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

Enalapril following captopril-induced nephrotic syndrome.

The development of proteinuria, and more rarely nephrotic syndrome, has been seen with the use of the first orally active converting-enzyme inhibitor captopril. Both of these side effects appear to occur more frequently when the drug is used at higher dose, particularly in the presence of renal impairment. We have used enalapril, a new orally active converting-enzyme inhibitor in the treatment of a patient with drug-resistant hypertension and renal impairment who previously developed nephrotic syndrome with captopril. Recurrence of the nephrotic syndrome was not seen in this patient during a period of 20 months on enalapril. On the contrary, urinary protein excretion over the same period was reduced to around 1 g in 24 hours. Our experience would suggest that enalapril may usefully be substituted for captopril in the treatment of hypertensive patients in whom the latter has caused proteinuria or nephrotic syndrome.

Adult↗
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↗
PubMed1986

Natural history of diabetes presenting age 40-69 years: a prospective study of the influence of intensive dietary therapy.

Two hundred and twenty-three newly-diagnosed symptomatic diabetic patients with onset age 40-69 years enrolled in a prospective study of intensive dietary management of diabetes were observed for a period of six years and the data obtained is analysed. The variables studied were weight and fasting levels of plasma glucose and insulin, and of serum total cholesterol and triglyceride. These tests were monitored throughout the study and in addition the oral glucose tolerance test was analysed at entry to the study, after six months intensive dietary management and again after 72 months. Blood pressure, electrocardiogram and the presence of posterior tibial artery pulsation were recorded at entry to the study and at 36 months and 72 months. Approximately 80 per cent of the patients were managed solely by dietary restriction for the entire six years, but 25 patients received oral hypoglycaemic drugs and 26 required insulin treatment. Weight, and fasting glucose and triglyceride values fell in the first few months of intensive dietary management. Analysis of possible risk factors in survivors and patients dead at six years showed no significant differences, apart from a higher mean age at diagnosis in those who died. During the six years of intensive dietary management the mortality from all causes in these diabetic patients was no greater than that for the general population of Northern Ireland.

Adult↗
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↗