Clinical endocrinology
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Clinical endocrinology · Apr 2001
Comparative StudyEffects of androgen deficiency and replacement on prostate zonal volumes.
Androgens play a key role in prostate development and disease. However the effects of androgen deficiency and replacement on the prostate during mid-life are not well understood, and there is no information on their effects on prostate zonal volumes. This study aimed to define the effects of androgen deficiency and androgen replacement therapy on prostate zonal volumes (central, peripheral & total) using planimetric prostate ultrasound with particular emphasis on the central zone of the prostate, the most hormonally sensitive and fastest growing region of the prostate and the zone where nodular benign prostate hyperplasia originates. ⋯ We conclude that, during mid-life, chronic androgen deficiency due to hypogonadism is associated with reduced central, peripheral and total prostate volumes. Reduced prostate volumes persist even during long-term maintenance of effective androgen replacement therapy with physiological testosterone concentrations until the fourth decade of life. After that, prostate volumes increase with age regardless of androgen deficiency or replacement. These findings suggest that, during mid-life, age is a more important determinant of prostate growth than ambient testosterone concentrations maintained in the physiological range. The persistently subnormal prostate volumes despite adequate androgen replacement therapy may explain the apparent paucity of cases of overt prostate disease among testosterone-treated androgen deficient men who retain protection against prostate disease despite physiological androgen replacement therapy.
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Clinical endocrinology · Mar 2001
Randomized Controlled Trial Clinical TrialInfluence of melatonin administration on glucose tolerance and insulin sensitivity of postmenopausal women.
The effect of melatonin on human carbohydrate metabolism is not yet clear. We investigated whether melatonin influences glucose tolerance and insulin sensitivity in aged women. ⋯ The present results indicate that in aged women administration of 1 mg of melatonin reduces glucose tolerance and insulin sensitivity. The present data may have both physiological and clinical implications.
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Graves' disease (GD) complicates 0.1% to 0.2% of pregnancies, but congenital thyrotoxicosis is rare occurring in one in 70 of these pregnancies independent of maternal disease status. Antenatal prediction of affected infants is imprecise; however, maternal history, coupled with a high maternal serum TSH receptor binding immunoglobulin index (TBII) predict adverse neonatal outcome. Mortality is reported to be as high as 25% in affected infants and would therefore be expected to be higher in premature infants. This study illustrates that in sick, premature, extreme low birth weight (ELBW) or intrauterine growth retarded (IUGR) infants, the diagnosis maybe overlooked especially in the absence of antenatal risk assessment and management of thyrotoxicosis in this setting is complex. ⋯ This is a large series of extremely small and premature infants with neonatal thyro-toxicosis. Presentation was nonspecific. The diagnosis was delayed because of low birth weight, prematurity, multiple birth and/or an unrecognized maternal history of Graves' disease. The treatment of neonatal thyrotoxicosis was difficult in these extreme low birth weight infants yet no infant died and significant morbidity was confined to high output cardiac failure in one infant. With antenatal recognition of past or active Graves' disease, assessment of maternal TSH receptor binding immunoglobulin index prior to delivery and postnatal monitoring of cord TSH and venous fT4 and TSH on days 4 and 7 rapid treatment of affected infants may have further reduced neonatal morbidity.
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To determine whether the initial presentation of patients with central precocious puberty (CPP) varies according to the aetiology, whether this permits the differentiation between idiopathic and organic forms, and whether the body mass index (BMI) and plasma leptin concentrations are linked to gonadotrophin secretion. ⋯ The features of central precocious puberty vary according to the aetiology, but it is impossible to exclude a central nervous system lesion in a given patient with central precocious puberty without performing central nervous system imaging. This imaging remains necessary in all cases of central precocious puberty. Most of the girls with idiopathic central precocious puberty had increased BMI, but we found no correlation between plasma leptin concentrations and gonadotrophin secretion.
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Clinical endocrinology · Jan 2001
Management of Nelson's syndrome: observations in fifteen patients.
To analyse the results of different treatment modalities for Nelson's syndrome, which was defined as radiological evidence of a pituitary macroadenoma, fasting plasma ACTH levels of more than 200 pmol/l after stopping glucocorticoid substitution for at least 24 h in a patient who had undergone bilateral adrenalectomy for Cushing's disease. ⋯ Our results demonstrate that pituitary surgery of Nelson's macroadenomas is more successful when Nelson's adenomas are relatively small. Pituitary surgery should be performed before extrasellar expansion of the tumour occurs in order to attain long lasting remissions. Pituitary irradiation should be performed postoperatively in all patients with residual tumour. Our data also illustrate that in patients with Nelson's syndrome, plasma ACTH levels can reliably be used as an indirect approximation for tumour volume.