PubMed Health⌕ Search

Biomedical subjects

F D Hofeldt

Publications and source records attributed to F D Hofeldt.

At least 19 recordsLinked to original sources
PubMed1991

Covert hypothyroidism presenting as a cardiovascular event.

Hypothyroidism presenting with classic signs and symptoms is generally easily recognized. Less often, patients with hypothyroidism may present with symptoms and laboratory abnormalities suggestive of cardiovascular disease. In this article, we describe six such patients. Hypothyroidism was suspected when creatine phosphokinase (CPK) levels were persistently elevated. The diagnosis was confirmed by thyroid function tests, and thyroid hormone therapy resulted in resolution of symptoms and CPK elevations. Persistently elevated CPK levels associated with cardiovascular symptoms but without demonstrable myocardial damage should prompt consideration of covert hypothyroidism.

Adult↗
PubMed1990

The effects of theophylline and nifedipine on corticotropin-stimulated cortisol secretion.

The adrenal cortisol response to corticotropin appears to involve both calcium and cyclic adenosine 3',5'-monophosphate (cAMP) as intracellular mediators. In 10 healthy male volunteers, the short-term administration of theophylline, which affects both intracellular calcium and cAMP, lowered basal cortisol levels but augmented the in vivo cortisol response to short-term corticotropin stimulation. Short-term administration of nifedipine, a calcium channel antagonist, had no effect on basal or peak cortisol levels but reduced the incremental cortisol response to corticotropin. The effects of both theophylline and nifedipine, although statistically significant, were modest and of questionable clinical significance but should be considered in the interpretation of the clinical corticotropin stimulation test. They may also provide some insight into the post-receptor actions of corticotropin.

Adrenal Cortex↗
PubMed1990

Cushing's syndrome in pregnancy.

Fertility and childbearing rarely occur in Cushing's syndrome because amenorrhea, oligomenorrhea, infertility, and abortions characterize the disease. Currently, a total of 53 cases of Cushing's syndrome and pregnancy have been reported. When Cushing's syndrome occurs during pregnancy, approximately 56 per cent of the cases are associated with adrenal cortical adenoma or carcinoma. Excluding Cushing's disease, nearly 21 percent of the cases are caused by adrenal carcinoma. The maternal catabolic state of glucocorticoid excess contributes to poor fetal outcome with many of the cases complicated by either fetal wastage or prematurity. However, congenital malformations are not seen more frequently than in normal pregnancy. Pregnancy may or may not influence Cushing's syndrome, but Cushing's syndrome definitely complicates pregnancy.

Adult↗
PubMed1990

Tamoxifen therapy for painful idiopathic gynecomastia.

We have evaluated the efficacy of the antiestrogen tamoxifen in six men with painful idiopathic gynecomastia. Subjects were given either tamoxifen or placebo for 2 to 4 months and then were given the other agent for an identical period. Breast size was considered to have been reduced only if it had decreased by one or more Marshall-Tanner stages during the treatment period. Pain reduction with tamoxifen therapy was statistically significant for the group, occurring in five of six subjects during tamoxifen treatment and in only one of six during the placebo period. Size reduction with tamoxifen was only marginally significant for the entire group, but occurred in all three subjects who were initially in Marshall-Tanner stage III and in none of the three subjects who were initially in stage V. During tamoxifen treatment, there was a significant increase in the serum levels of luteinizing hormone and total estradiol and a marginally significant increment in the total testosterone level.

Adult↗
PubMed1990

Effects of a continuous thyrotropin-releasing hormone infusion on gonadotropin-releasing hormone-stimulated gonadotropin secretion.

We examined the effects of elevated thyrotropin-releasing hormone (TRH) levels on the gonadotropin response to gonadotropin-releasing hormone (GnRH) in 16 healthy men. A TRH infusion, which was begun 15 minutes before and continued for 120 minutes after the bolus administration of GnRH, was compared with a saline infusion. During the TRH infusion the gonadotropin responses to acute GnRH stimulation were higher than in the saline control period but, although statistically significant, the differences were small in magnitude and were similar to the intraindividual coefficient of variation in gonadotropin responses determined under control conditions. They did not appear to be of clinical significance. TRH significantly lengthened the interval between GnRH administration and the appearance of peak gonadotropin levels. These results indicate that a brief TRH infusion, producing mild elevations of thyrotropin and prolactin, causes slight alterations predominantly in the timing of GnRH-stimulated gonadotropin secretion.

Adult↗
PubMed1989

Reactive hypoglycemia.

Reactive hypoglycemia is a relatively uncommon meal-induced hypoglycemic disorder. Most patients with adrenergic-mediated symptoms have a diagnosis other than reactive hypoglycemia. In many patients with this self-diagnosis, other disorders can be attributed as a cause for symptoms, especially neuropsychiatric disease. The continued use of the terminology "functional hypoglycemia" only contributes vagueness to our correct understanding of this metabolic condition. There are a number of conditions associated with postprandial hypoglycemia. One category is the reactive hypoglycemias, which occur in patients with diabetes mellitus (diabetes reactive hypoglycemia), gastrointestinal dysfunction (alimentary reactive hypoglycemia), hormonal deficiency states (hormonal reactive hypoglycemia), and a large patient group characterized as having idiopathic reactive hypoglycemia. Of these causes the alimentary, hormonal, and diabetic patients are less disputed, whereas the idiopathic reactive hypoglycemic group has been referred to as a "nondisease" group. Characteristic alterations in insulin secretion accompany each of these conditions. In bona fide patients, dysinsulinism or hyperinsulinism usually accounts for the hypoglycemia. Some patients may have increased insulin sensitivity, but this association is doubtful or very rare. Patients with this meal-related eating disorder are characterized as ingesting excessive quantities of refined carbohydrate. In the research setting, the disorder can easily be elicited with the oral glucose tolerance test. However, to establish clinical relevance, the hypoglycemia needs documentation in the home setting with measurements of blood glucose during a postpradial symptomatic episode. The reactive hypoglycemic patients are frequently confused with patients with underlying psychiatric illness. Both syndromes are similar, with adrenergic-mediated symptoms and a common characteristic personality as noted on Minnesota Multiphasic Personality Inventory (MMPI) testing. Patients with bona fide meal-related reactive hypoglycemia should be treated primarily with dietary restriction of refined carbohydrates; other patients may require medications.

Blood Glucose↗
PubMed1987

Effects of hypothyroidism and short-term aging on whole blood thromboxane and arterial prostacyclin synthesis.

Hypothyroidism results in decreased platelet aggregation and has unique effects on the development of atherosclerosis and angina pectoris. Because prostacyclin and thromboxane A2 profoundly influence platelet function and vascular tone and are thought to be important in the development of atherosclerosis and angina pectoris, we studied the effects of hypothyroidism in rats on the in vitro elaboration of prostacyclin passively by aortic tissue and of thromboxane A2 by thrombin-stimulated whole blood. Hypothyroidism induced by iodine 131 (given at age 7 weeks) persistently caused a mild decrease in platelet count (P less than 0.01) and 30% decrease in immunoreactive thromboxane B2 (the hydrolysis product of thromboxane A2) generation per platelet (P less than 0.01) compared with age-matched euthyroid rats. Between 20 and 23 weeks of age immunoreactive 6-ketoprostaglandin F1 alpha (the hydrolysis product of prostacyclin) generation decreased by 30% in euthyroid rats. In hypothyroid rats less than 23 weeks of age, 6-ketoprostaglandin F1 alpha production was the same as that of age-matched euthyroid rats. With further aging, 6-ketoprostaglandin F1 alpha production did not decrease as it did in euthyroid rats. Hypothyroid rats more than 20 weeks old had, therefore, significantly greater 6-ketoprostaglandin F1 alpha production than age-matched euthyroid rats (P less than 0.005). L-Thyroxine given daily for 28 days to 23-week-old hypothyroid rats caused a rapid increase in platelet count and a delayed normalization of the thromboxane synthetic abnormality. 6-Ketoprostaglandin F1 alpha production transiently increased in response to L-thyroxine, but decreased to the euthyroid level after 28 days of therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

6-Ketoprostaglandin F1 alpha↗
PubMed1986

Hyperthyroidism following hypothyroidism.

Two patients are presented who developed autonomous thyrotoxicosis following a diagnosis of primary hypothyroidism. In one of these patients, antibodies to the TSH receptor were typical of Graves' disease when measured as thyrotropin binding inhibitor immunoglobulins (TBII) and as human thyroid adenylate cyclase stimulating (HTACS) activity, while a needle biopsy of the thyroid gland was consistent with lymphocytic thyroiditis. Twenty-one other reported cases of this unusual sequence found in the literature are reviewed. This occurrence is more common than is generally appreciated.

Adult↗
PubMed1977

Abnormal sella turcica. A tumor board review of the clinical significance.

Sixty of 146 patients with intracranial neoplasms or arterial aneurysms had roentgenographic abnormalities of the sella turcica. These abnormalities were most commonly due to chromophobe adenoma, craniopharygioma, and acromegaly, but ten of them were caused by lesions arising distant to the sella. There were also three cases of empty sella syndrome. Headache, visual disturbance, and sexual dysfunction were the most frequent presenting complaints, with visual field abnormality being most common. Pituitary dysfunction was manifested most frequently by alterations in growth hormone level and gonadotrophin secretion and less frequently by hypothyroidism and adrenocortical insufficiency. When the abnormal sella was associated with evidence of symptomatic intracranial disease, endocrine dysfunction, or visual field compromise as evidence of an anatomically aggressive intracranial neoplasm, specialized neuroroentgenographic localizing procedures were usually positive, and treatment for most of the causative lesions was highly effective.

Acromegaly↗
PubMed1977

"Masked" 21-hydroxylase deficiency of the adrenal presenting with gynecomastia and bilateral testicular masses.

An infertile 27 year old man with precocious puberty is described. He presented in adulthood with unilateral and then bilateral gynecomastia, and subsequently testicular tumors developed. An early diagnosis of congenital adrenal hyperplasia would have avoided unnecessary surgery. Initial detailed metabolic evaluation led to the erroneous diagnosis of 11-hydroxylase deficiency because of the presence of an unusual steroid (21-desoxycortisol) in serum which was falsely reported as an increased 11-desoxycortisol (compound S). The observed low urinary pregnanetriol measurements would have supported this diagnosis. Subsequent specific measurements of 21-desoxycortisol established its presence in the serum and its major metabolite, tetrahydro-21-desoxycortisol, in the urine. The unique features in this case of 21-hydroxylase deficiency alert the physician to its unusual clinical presentation and the pitfalls that may be encountered when evaluating adrenal steroidogenesis.

Adrenal Glands↗
PubMed1976

Low dose radioiodide thyroid ablation in postsurgical patients with thyroid cancer.

Sixty-four patients with well-differentiated carcinoma of the thyroid were treated with initial high (80 to 100 mCi) or low (less than 30 mCi) doses of I131 after bilateral subtotal thyroidectomy. A total of 36 patients in the various histologic categories were initially treated with the low dose of I131 (group 1), and a total of 28 patients were treated with the higher dose (group 2). Disease-free criteria were no visible tissue in the neck or body, a protein-bound radioactive iodine (PBI131) of less than 0.005 per cent per liter at seven days and/or whole body retention of less than 3 per cent at seven days. Of the patients receiving less than 30 mCi (group 1), 56 per cent with papillary carcinoma, 67 per cent with follicular carcinoma and 56 per cent with mixed carcinoma of the thyroid were rendered disease-free after this initial dose. Of the patients receiving the higher dose of I131 (group 2), 67 per cent with papillary carcinoma, 50 per cent with follicular carcinoma and 67 per cent with mixed carcinoma of the thyroid were rendered disease-free after this initial dose. Disease-free mean follow-up time was 5.17 years (group 1) and 5.82 years (group 2). There was no statistical difference in these mean follow-up times, nor was there a statistical difference in the net (total minus initial) dose of I131 needed to render the patient disease-free. These data demonstrate that low dose I131 therapy is as effective as the larger more routine doses of I131 given in this disease.

Adenocarcinoma↗
PubMed1976

Isolated galactorrhea with normal serum prolactin levels: clinical implications.

Detailed endocrine-metabolic studies were performed on five women who were otherwise well but who had had inappropriate breast secretions for variable periods of time (three months to 16 years). Our results suggest that the presence of a lactose-containing breast secretion, which strictly defines galactorrhea, does not necessarily indicate a recognizable abnormality if normal hypothalamic-pituitary function is present. In these regularly menstruating women with isolated galactorrhea, we suggest a minimum initial evaluation, but careful long-term follow-up studies to identify those cases which may progress to the other recognized, more serious amenorrhea-galactorrhea syndromes.

Adult↗
PubMed1976

Use of the Anger scintillation camera for determining thyroid uptake.

Nineteen patients, representing a spectrum of thyroid function, were studied. The mean 24-hr thyroid 131I uptakes determined by a standard counting procedure and by our scintillation camera counting method were 15.0% and 16.4%, respectively, for the entire patient population. The 24-hr 131I uptakes from these two methods correlated with a coefficient of 0.99. A high degree of correlation between the two methods was found in evaluating euthyroid and hypothyroid patients and a similar finding was noted in the one hyperthyroid patient studied.

Adult↗