Depressed thyroid indexes associated with occupational exposure to inorganic lead.

The finding of low values for serum thyroxine and estimated free thyroxine in seven of 12 workers referred because of elevated blood lead levels (greater than 40 mg/L) prompted further investigation. In a cross-sectional study of workers at a small foundry, both measurements were found to regress negatively with blood lead level. In 12 of 47 subjects, both indexes were in the hypothyroid range. Serum thyrotropin and triiodothyronine levels in patients and study subjects with low indexes were all normal. Physical examinations failed to demonstrate the classic features of hypothyroidism. These data are compatible with a central depression of the thyroid axis or an alteration in thyroxine metabolism or binding to proteins. Irrespective of mechanism, the association between low thyroid indexes and elevated lead levels merits attention because of the large number of workers exposed to lead and the similarities between the clinical features of adult lead poisoning and hypothyroidism.

Hypoglycemia-induced prolactin release.

Recent advances in neurosurgical techniques have made it possible to remove pituitary adenomata with minimal morbidity and mortality. These developments have focused attention on early recognition of pituitary tumors, before the onset of visual disturbances or endocrine dysfunction. We have studied the prolactin response to insulin-induced hypoglycemia as an aid in the evaluation of patients with hypothalamic and pituitary disease. Regular insulin 0.1 units/kg was administered intravenously to normal subjects, to patients with pituitary tumors, and to patients with idiopathic galactorrhea. While the normal subjects regularly showed a prolactin response to hypoglycemia, this was observed infrequently in the other groups. It is possible that prolactin nonresponsiveness to insulin hypoglycemia may reflect nonspecific pituitary damage or may represent an abnormality specific to patients with galactorrhea. Our data suggest that the prolactin response to insulin hypoglycemia is a sensitive index of hypothalamic-pituitary dysfunction.

Erythrocyte insulin binding in insulin-dependent diabetes mellitus: lack of relationship to duration and control of diabetes in children and adolescents.

Insulin binding was measured in the erythrocytes (RBCs) of four children and 12 adolescents with insulin-dependent diabetes mellitus in the basal (fasting, nonketotic) state. Children and adolescents with insulin-dependent diabetes mellitus showed normal binding of insulin to their RBCs when expressed as the total insulin bound over the physiologic range of insulin concentrations. The insulin receptor concentration and receptor binding affinity for insulin were also normal. These parameters of insulin binding were not correlated with either the duration of diabetes or the degree of diabetic control in the patients. Since insulin binding by erythrocytes has been shown to reflect binding by traditional target tissues (liver, fat), the data suggest that alterations in binding of insulin to cells in children and adolescents with insulin-dependent diabetes mellitus probably play little, if any, role in the response of these patients to exogenous insulin or in the control of their glucose metabolism in the basal state.

Endocrine and reproductive dysfunction in men associated with occupational inorganic lead intoxication.

In an attempt to define a postulated effect of lead on male endocrine function, seven men with symptomatic occupational lead intoxication (maximum whole blood lead levels 66-139 micrograms/dl) underwent in-patient endocrine evaluation at the time of diagnosis. Defects in thyroid function, probably of central origin, were present in three patients. Six patients had subnormal glucocorticoid production measured by 24-hr urinary 17-hydroxycorticosteroids and plasma cortisol responses to vasopressin- and/or insulin-induced hypoglycemia. Although serum testosterone concentration was normal in six patients, five had defects in spermatogenesis, including two with oligospermia and two with azoospermia. Repeat examinations after chelation therapy showed only partial improvement. It is concluded that heavy occupational exposure to lead, sufficient to cause clinical poisoning, may be associated with diffuse disturbances of endocrine and reproductive functions in men which are not rapidly reversible with standard treatment. Since men without overt poisoning have not been studied, these results cannot yet be included as sequelae of low-dose exposures.

Anterior pituitary function in women with postpartum hemorrhage.

Thirteen asymptomatic women with postpartum blood loss of at least 500 cc were evaluated for anterior pituitary endocrine function. Insulin tolerance tests and TRH stimulation tests were done and determinations made for serum growth hormone, cortisol, thyrotropin, and prolactin. There was no laboratory evidence of pituitary dysfunction in this group of 13 patients. Subclinical hypopituitarism in women with previous postpartum hemorrhage would appear to be uncommon.

Ectopic ACTH syndrome due to pheochromocytoma: case report and review of the literature.

A 51-year-old female was diagnosed preoperatively to have a pheochromocytoma producing ACTH. This diagnosis was based upon her paroxysmal hypertension, hyperpigmentation, and hypokalemia. Elevated levels of serum and urine corticosteroids, plasma ACTH, urinary VMA, and catecholamines fell after a right adrenal pheochromocytoma was removed. Subsequently this tumor was found to have a high content of ACTH. Review of the literature indicates a mortality rate of 57% for this syndrome. Proper preoperative recognition and management can result in total cure.

The relationship of cognitive, personality, and academic measures to anesthesiology resident clinical performance.

UNLABELLED: Cognitive skills (including vigilance), personality factors, and standardized academic test performance may be associated with clinical competence in anesthesiology to varying degrees. Sixty-seven anesthesiology residents in training at one center between 1993 and 1995 were administered the modified Vigil (For Thought, Ltd., Nashua, NH), the Paced Auditory Serial Addition Test, the California Personality Inventory, the State-Trait Anxiety Inventory, and five standardized academic performance tests. The clinical performance of anesthesiology residents was rated on a quarterly basis by a clinical competence committee. A growth curve model indicated that there was significant variability in clinical competence at the start of residency and a statistically significant improvement over time, and that the relative ranking of the residents remained stable over the course of training. Of 46 potential variables, 7 were associated (P < 0.10) with poor clinical performance; these were subjected to a multivariate test (Mantel-Haenszel). Cognitive variables predicting poor clinical performance were difficulty performing a rapid mental arithmetic test requiring divided attention and commission errors during complex visual target detection. Personality variables predicting poor clinical performance were introversion and flexibility. A predictive academic variable was poor anesthesia knowledge as measured by using two different tests during the first month of training. There were varying levels of independence among these variables. IMPLICATIONS: Early academic test performance and certain cognitive and personality tests were associated with the clinical performance of anesthesiology residents. The predictive value of these findings should be confirmed in a prospective, multicenter study.