Graves' ophthalmopathy--a clinical review

Graves' ophthalmopathy occurs in 2% to 7% of patients with Graves' disease with the major manifestations being proptosis, ophthalmoplegia, optic neuropathy and/or eyelid retraction. Although autoimmune in nature, the precise pathophysiology is unknown. The course of the ophthalmopathy is not influenced by the mode of treatment of the hyperthyroidism. In addition to restoration of the euthyroid state, the aims of treatment include relief of eye pain, correction of extraocular muscle dysfunction, protection of visual acuity and improvement of appearance. Specific therapy depends on the severity of the ophthalmopathy and varies from lubricating eye drops in mild disease to high-dose steroids and radiotherapy or decompressive surgery in severe cases.

Effects of combined insulin-sulfonylurea therapy in type II patients

We conducted a double-blind crossover study to determine which patient characteristics best predict a beneficial response to combined insulin-glyburide therapy. Glyburide (15 mg/day) or placebo was added to the treatment regimen of 31 insulin-treated type II (non-insulin-dependent) diabetic subjects. During glyburide therapy, there was a significant improvement in glycemic control with a reduction in glycosylated hemoglobin from 9.9 +/- 1.3 to 9.1 +/- 1.3% (P less than .001). Patients who responded had higher fasting C-peptide levels (P less than .001) and shorter durations of insulin therapy (P less than .01) than those who did not respond. Glyburide withdrawal was associated with a greater than expected deterioration in glycemic control. Patients on insulin therapy for greater than 8 yr are unlikely to benefit significantly from the addition of glyburide to their treatment regimen.

Candidiasis-endocrinopathy syndrome with progressive myopathy

A women suffering from the candidiasis-endocrinopathy syndrome, developed severe myopathy in her fourth decade and died from it at the age of 37 years. Associated conditions were hypoparathyroidism, vitiligo, chronic mucocutaneous candidiasis, short stature, intellectual disability, ovarian failure and alopecia totalis. Muscle biopsy findings were non-specific with focal atrophy of type 2 fibres. Serum immunoglobulin levels were normal. The only demonstrable abnormalities of her immune system were impaired T-cell function and antibody production by B-cells (detectable to smooth muscle, mitochondria and gastric parietal cells). The T-cell abnormality may have been part of a more generalized cell defect, resulting from an unidentified genetic abnormality, whilst the circulating antibodies could have been a response to tissue damage. There was no convincing evidence of primary autoimmune damage.

Hypertrophic and functional response to experimental chronic aortic regurgitation

Aortic regurgitation was induced by retrograde perforation of an aortic valve cusp under hemodynamic guidance in 12 New Zealand White rabbits. Regurgitant fraction was documented by electromagnetic flow probe and six sham-operated animals served as controls. Two-dimensional, M-mode and Doppler echocardiography was performed pre-operatively and serially post-operatively for 3 to 6 months. Animals with aortic regurgitation developed progressive left ventricular dilatation and eccentric hypertrophy. Left ventricular internal dimension at end-diastole and left ventricular mass were increased from baseline values by 41 and 94% (P less than 0.001), respectively; fractional shortening was stable while end-systolic stress increased 50% (P less than 0.01. Thus, acutely induced aortic regurgitation in rabbits results in a chronic model which may be appropriate for stimulation of the hypertrophic response to aortic regurgitation in humans.

Reduced adrenal androgens in patients with myotonic dystrophy

Endocrine disturbances associated with myotonic dystrophy (MD) include testicular atrophy, hyperinsulinemic glucose intolerance, thyroid abnormalities, and low or low normal urinary 17-ketosteroid (17-KS) excretion. Since the major circulating precursors of urinary 17-KS are dehydroepiandrosterone sulfate (DHAS) and dehydroepiandrosterone (DHA), a decrease in adrenal androgen production has been suggested. This possibility was studied in 19 MD patients and 19 age- and sex-matched normal subjects. Each patient had a 24-h urine collection for 17-KS and cortisol determinations, a 4-h iv infusion of 25 micrograms tetracosactrin with serial measurements of serum DHAS, DHA, and cortisol, and an insulin-induced hypoglycemia test. Sixteen patients had 0800 and 2400 h serum collections for cortisol estimations. Serum DHAS [1.0 +/- 0.5 (+/- SD) vs. 3.9 +/- 1.9 mumol/liter; P less than 0.0005] and DHA (5.9 +/- 2.7 vs. 11.0 +/- 7.1 nmol/liter; P less than 0.005) levels were significantly lower in MD patients than in normal subjects; cortisol levels were higher (540 +/- 222 vs. 394 +/- 128 nmol/liter; P less than 0.01), almost certainly a reflection of stress. A normal diurnal cortisol rhythm was found in all 16 subjects. Cortisol responses to insulin-induced hypoglycemia were normal, increasing from 345 +/- 243 nmol/liter to a maximum of 831 +/- 282 nmol/liter. Urinary 17-KS excretion was low or low normal, while urinary cortisol levels were normal in 18 and mildly elevated in 1 patient. There was a significant correlation between 17-KS and DHAS levels (r = 0.46; P less than 0.05). DHAS, DHA, and cortisol responses to tetracosactrin infusion were similar in patients and normal subjects. It is concluded that 1) in MD patients, serum DHAS and DHA concentrations are significantly lower than those in normal subjects, explaining the frequent reports of low or low normal 17-KS excretion; 2) the reduced DHAS and DHA concentrations are most likely due to decreased production rather than increased clearance; and 3) glucocorticoid production is normal.

Quantitative bone histology in the hypercalcemia of malignant disease

Quantitative bone histology was studied in 23 patients with malignant hypercalcemia (MH) due to carcinoma (16) or immunoproliferative disease (7). Plasma calcium was 3.37 +/- 0.47 (mean +/- SD) mmol/liter. Bone resorbing surface (RS) was measured using a sensitive histochemical stain to identify osteoclasts. In the MH patients with carcinoma, the RS was 3.1 +/- 2.6% compared to 1.0 +/- 0.3% in controls (P less than 0.02). In the myeloma patients it was 2.3 +/- 1.7%, and in normocalcemic patients with malignant disease 0.8 +/- 1.1%. RS did not correlate with serum PTH, and several high RS values were associated with undetectable PTH. RS correlated with forming surface (FS) in MH patients (r = 0.44, P less than 0.05) and controls (r = 0.68, P less than 0.005), but there was a greater RS relative to FS in MH patients than in controls (P less than 0.005). "Excess" RS in the MH patients was calculated by subtracting the RS accounted for by the measured FS, using the relationship defined by the controls. Bone loss, as reflected in urinary calcium excretion, correlated weakly with excess RS (r = 0.44, P less than 0.05) but was high even when excess RS was zero. Thus, the histological findings do not account for the bone loss, and additional resorption around bone metastases is likely; the results of this study are consistent with a humoral substance produced by the malignant tissue causing generalized bone resorption in addition to bone dissolution around metastases.

Thyroid abnormalities in patients with myotonic dystrophy

Myotonic dystrophy (MD) is a systemic genetic disorder predominantly affecting musculature. Although endocrine disturbances have been described, data relating to thyroid gland involvement are sparse and conflicting. To further investigate this aspect, twenty MD patients and twenty age-and sex-matched controls were studied. All were clinically euthyroid and there were no significant differences between circulating levels (mean +/- SD) of T4 (101 . 5 +/- 28.2 v. 103 . 8 +/- 27 . 7 nmol/l), T3 (1 . 86 +/- 0 . 57 v. 2 . 15 +/- 0 . 47 nmol/l), rT3 (0 . 39 +/- 0 . 14 v. 0 . 42 +/- 0 . 09) nmol/l) or TSH (2 . 6 +/- 0 . 5 v. 2 . 4 +/- 0 . 8 mu/l) or between T3 resin uptakes (97 +/- 8 v. 98 +/- 11%). TSH responses following TRH stimulation were significantly less in the MD patients (323 +/- 141 v. 529 +/- 240%; P less than 0.0025). The mean maximum TSH levels achieved were 6 . 7 +/- 3 . 6 mu/l (MD) and 17 . 1 +/- 7 . 2 mu/l (controls); P less than 0.005. Two patients had multinodular goitres (MNG) and one a single thyroid nodule. Thyroid scans were normal except for patchy uptake in the two MNG patients. There was no abnormal incidence of circulating thyroid microsomal or thyroglobulin antibodies, and thyrotrophin binding inhibitory immunoglobulin levels were normal in four patients. It is concluded that in MD: 1 palpable thyroid gland abnormalities occur with increased frequency, 15% (three/twenty) in the present study and 20% (twenty/102 case reports) from a review of the literature; 2 TSH responses to TRH are significantly reduced; 3 circulating thyroid hormone levels are usually normal.

Studies of the ideal [H+] for perfusional preservation

The neutral point of water, being a function of its dissociation constant, is temperature dependent. This is also true of protein-buffered solutions such as perfusates. In organ preservation these facts have been long ignored and, as a result, perfusions have been carried out in a relatively acidotic environment. These studies evaluated the effects of correcting the pH partially or completely for the level of hypothermia involved in perfusional preservation. The findings both in rabbits and dogs were that a pH of 7.4 (measured at 7 C) is dangerously close to the pH below which there is rapid deterioration of function. On the other hand, perfusate pHs up to 7.75 in dogs and 8.25 in rabbits were tolerated at no detriment. As a result, the recommendation is made to carry out hypothermic organ perfusion at a pH well above 7.4; 7.60 or 7.65 seems reasonable.

The relationship of adrenal androgens to the secretory patterns for cortisol, prolactin, and growth hormone during early puberty

Serum concentrations of dehydroepiandrosterone (DHA), dehydroepiandrosterone sulfate (DHA-sulfate), cortisol, prolactin, and growth hormone were measured at half-hour intervals for 24 hr in five healthy children aged 8--13 yr. Their adolescent development was assessed by clinical staging, plus determinations of serum FSH, LH, testosterone and estradiol during both wakefulness and sleep. Correlative analysis indicates that there was synchronous secretion of DHA and cortisol, implying regulation of both by ACTH. With advancing age and sexual maturation, there was a progressive rise in mean serum DHA and DHA-sulfate levels, but no similar change in serum cortisol concentrations. There was evidence for enhanced secretion of both growth hormone and prolactin during sleep in all subjects (including one who was hyperprolactinemic), but there was no obvious relationship between levels of these pituitary hormones and the early pubertal rise in adrenal androgens.

Effect of ovine prolactin on serum somatomedin bioactivity in hypophysectomized female rats

Ovine prolactin (oPRL) increased serum somatomedin (SM) bioactivity in hypophysectomized female rats. ACTH, in small but not large doses, augmented this oPRL effect. These results suggest that in the female rat PRL may regulate SM production. Adrenal factors may variably modulate SM production or serum SM bioactivity.

Prolactin-secreting tumors and hypogonadism in 22 men

We studied 22 men with prolactin-secreting pituitary tumors and hypogonadism. Twenty complained of impotence, nine had visual impairment, and three experienced galactorrhea. None of the 17 patients undergoing operation or radiotherapy, or both, were subsequently normoprolactinemic. In all 13 patients treated with bromocryptine major clinical improvement was associated with a decrease in serum prolactin levels and in nine with an increase in serum testosterone. Two patients receiving testosterone replacement therapy showed improved potency only after bromocryptine was administered. The results indicate that hyperprolactinemia frequently induces hypogonadism in men, that bromocryptine ameliorates symptoms of disease previously unchanged by operation or radiotherapy, and that the impotence observed may not be solely the result of hypogonadism.

Nursing-mediated prolactin and luteinizing hormone secretion during puerperal lactation

Alterations in plasma prolactin (PRL) concentrations in response to nursing in puerperally lactating women are often significant beyond the 90th postpartum day, yet the increment appears unrelated to the frequency or duration of the nursing stimulus. Tonic gonadotropin secretion is low, assuming a more episodic secretory pattern either when the frequency of breast-feeding is reduced or when weaning takes place. Significant increments in peripheral concentrations of luteinizing hormone can be seen in response to weaning coincident with a fall in peripheral plasma PRL concentration. At the same time, peripheral estrogen concentrations increase, suggesting that a specific set point for ovarian responsiveness to gonadotropins exists. Whether this set point is related solely to the peripheral concentration of gonadotropins or whether it is also related to the peripheral PRL concentration is not known at this time.

Hormonal changes in girls with precocious adrenarche: a possible role for estradiol or prolactin

Serum concentrations of dehydroepiandrosterone, DHA sulfate, estradiol, and prolactin in 20 girls with precocious adrenarche were compared with those of healthy girls of varying age and degrees of breast and sex hair development. Production of adrenal androgens, as reflected by serum DHA and DHA-sulfate concentrations, was significantly increased in PA above that in age-matched control subjects. Surprisingly, in spite of their lack of breast growth, the patients with PA also had serum estradiol levels that were higher than in the prepubertal girls and similar to those found in girls with both breast and pubic hair development. Serum prolactin concentrations in the patients with PA were not increased over those of the age-matched (less than 8 years) prepubertal girls. In the older prepubertal ( greater than 8 years) and early pubertal girls serum prolactin levels were lower. The finding of increased estradiol levels suggests that precocious adrenarche is not a distinct endocrine entity, but merely represents a variant of early adolescence in which estrogen secretion is sufficient to influence adrenal 3beta-hydroxysteroid dehydrogenase activity with a resultant rise in DHA production, but not sufficient to produce clinically apparent breast changes. The data do not support a similar role for prolactin.

Effects of triiodothyronine administration in patients with chronic renal failure

Clinically euthyroid patients with severe, chronic, non-thyroidal illnesses usually have decreased serum total and absolute free T3 concentrations. Since T3 is the metabolically more active of the two thyroid hormones, it has been suggested that these patients may be hypothyroid and thus may benefit from T3 therapy. To test this hypothesis, five patients with chronic renal failure requiring maintenance haemodialysis were treated with 5 microgram T3 eight hourly, increasing at three weekly intervals to 10 microgram eight hourly, 20 microgram eight hourly and finally 30 microgram eight hourly. The mean +/- SD serum T3 level did not change over the 12 week period (1.42 +/- 0.17 vs. 1.41 +/- 0.26 nmoll-1 whilst the mean serum T4 and TSH levels fell from 87.0 +/- 15.2 to 47.5 +/- 18.8 nmoll-1 and 1.9 +/- 0.9 to 1.3 +/- 1.6 mUl-1 respectively. Only the change in T4 levels was significant (P less than 0.005). A significant decrease in mean serum T4 levels was apparent even after the treatment period with 5 microgram T3 eight hourly (87.0 +/- 15.2 vs. 51.2 +/- 15.7; P less than 0.005). The mean fasting serum triglyceride level fell from 1.16 +/- 0.74 to 0.94 +/- 0.74 mmoll-1 (P less than 0.05) and the mean fasting serum cholesterol level fell from 6.06 +/- 1.13 to 4.69 +/- 1.10 mmoll-1 (P less than 0.05). There were no subjective improvements in any of the patients. From the marked changes in serum T4 levels during the administration of T3, it is concluded that, prior to treatment, the patients were biochemically euthyroid and not hypothyroid and thus did not require T3 therapy.

Adrenocortical function in hyperprolactinemic women

To study the effects of prolactin (PRL) on adrenocortical function in humans, dehydroepiandrosterone (DHA), dehydroepiandrosterone sulfate (DHAS), androstenedione (delta) and testosterone (T) were measured in serum obtained from 35 hyperprolactinemic women with galactorrhea and amenorrhea before and after treatment with bromocriptine-induced fall in mean PRL levels from 82 +/- 8 (SE) to 14 +/- 2 ng/ml (n = 39, P less than 0.0005), DHAS fell from 322 +/- 21 to 237 +/- 21 microgram/dl (n = 39); P less than 0.0005), DHA fell from 492 +/- 47 to 378 +/- 30 ng/dl (n = 39; P less than 0.01) while T (n = 16) and delta (n = 13) levels were unchanges (44 +/- 4 vs. 49 +/- 4 ng/dl and 280 +/- 55 vs. 236 +/- 40 ng/dl, respectively). In addition, 4 women were infused iv with 25 microgram synthetic ACTH over 4 h and serial blood samples drawn while hyperprolactinemic, and again 2-4 months later following normalization of PRL levels by bromocriptine. Although pre-infusion levels of DHAS were lower when PRL levels were normalized, no significant differences in responses of circulating DHAS, DHA, T, cortisol and 17-hydroxyprogesterone concentrations were detected between the two infusions. Since DHAS is virtually an exclusive product of the adrenal cortex, and since high PRL levels appear to inhibit ovarian steroid production, the findings suggest that hyperprolactinemia selectively stimulates adrenocortical androgen production.

Circulating thyroid hormone levels in children

Extensive use of radioimmunoassay for routine measurement of serum thyroid hormones in paediatric thyroid disorders showed inconsistencies between laboratory results based upon adult criteria and clinical observation. To resolve this disparity, serum triiodothyronine (T3) and thyroxine (T4) levels were measured by radioimmunoassay in 354 healthy children aged between 3 weeks and 17 years. The mean serum T3 concentration in children up to 10 years of age was 1·94±0·35 ng/ml (SD) which was higher than the mean serum T3 of 1·37±0·25 ng/ml in healthy adults. Similarly, the mean serum T4 of 10±2·5 μg/100 ml was higher than the adult mean serum T4 of 8·5±1·5 μg/100 ml. Neither concentration changed significantly from 3 weeks to 10 years of age, nor was there any sex difference. In girls serum T3 and T4 concentrations declined gradually from age 10 to maturity. A perimenarcheal nadir observed in the T4 data was thought to reflect the joint effects of the age-dependent fall in circulating T4 and the concomitant oestrogen-dependent rise in thyroxine-binding globulin. In boys the decline in serum T3 occurred approximately 2 years later than in the girls. These observations show that the normal ranges for serum T3 and T4 in children are higher than those in adults and that reference to normal adult ranges may lead to misclassification in diagnosis and monitoring of paediatric thyroid disorders.

Inhibition of conversion of thyroxine to triiodothyronine in patients with severe chronic illness

Many clinically euthyroid patients with severe, chronic, non-throidal illnesses (i.e. sick euthyroid patients) have very low circulating concentrations of total and absolute free triiodothyronine (T3), low-normal concentrations of total thyroxine (T4), elevated concentrations of absolute free T4, and circulating concentrations of thyrotrophin (TSH) that are either normal or subnormal. This study was undertaken to elucidate the mechanism of the low circulating T3 concentrations. The disappearance rate of 125 I-T3 from the circulation of five representative sick euthyroid patients was studied and found to be slower, but not significantly so, compared with three control subjects, thus excluding an increased destruction rate as the cause of the low T3 levels. A selective decrease of T3 secretion from the thyroid gland of these patients was also excluded by the results of TSH stimulation tests. Inhibition of extra-thyroidal conversion of T4 to T3 was suggested by studies of the thyroid function in a hypothyroid woman with a Grade IV lymphoma on T4 replacement therapy. When the lymphoma was in remission, her circulating T3 concentration was 2-55 nmol/l but when it relapsed it fell to 0-55 nmol/l. The T4 concentrations were 124-7 nmol/l and 126 nmol/1 respectively. Decreased monodeiodination of T4 to T3 in sick euthyroid patients was confirmed by paper chromatography of extracted serum obtained 48 h after an i.v. injection of 125 I-T4 into two severely ill patients from the intensive therapy unit and a control subject. Peaks of radioactivity corresponding to 125 I-T4 and 125 I-T3 were detected in the control subject, but only a single peak corresponding to 125 I-T4 was detected in the ill patients.

P-wave abnormalities in hyperthyroidism

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