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Biomedical subjects

A T Guay

Publications and source records attributed to A T Guay.

At least 37 records · Page 2Linked to original sources
PubMed1991

Possible hypothalamic impotence. Male counterpart to hypothalamic amenorrhea?

Twenty-one men with erectile complaints who were found to have a low level of serum testosterone without a reciprocal elevation of the serum levels of luteinizing hormone were evaluated to identify whether the defect was of hypothalamic or of pituitary origin. Patients underwent a luteinizing hormone (LH)-follicle-stimulating hormone (FSH)-releasing hormone stimulation test that showed a normal but sluggish increase in LH and FSH levels, thus ruling out a pituitary defect and suggesting a suprapituitary abnormality. This was confirmed when, in response to clomiphene, patients had a normal increase in gonadotropin and testosterone levels. Although the basal as well as clomiphene and gonadotropin releasing hormone-stimulated levels of total testosterone and gonadotropins were identical in men less than and more than fifty years old, the elevation of free testosterone levels in response to clomiphene was higher in patients younger than fifty. This suggested that although the primary abnormality found in these patients is altered secretion of gonadotropin hormone-releasing hormone from the hypothalamus, an age-related decline in the responsivity of Leydig cells to LH may make it more manifest in older patients. Elevation of testosterone levels from a subnormal to a normal range in response to clomiphene administered for seven days suggests that the defect is functional and reversible and that the drug may be useful in treatment of sexual dysfunction in this group of patients.

Aging↗
PubMed1991

Susceptibility to subacute thyroiditis is genetically influenced: familial occurrence in identical twins.

Subacute thyroiditis is thought to be virally induced in genetically predisposed individuals because a strong association has been suggested recently between HLA-B35 and patients in whom subacute thyroiditis has developed. Two identical twin brothers were seen at our clinic with the same symptoms and date of onset of hyperthyroidism and enlargement and tenderness of the thyroid, which gave us a unique opportunity to study the genetic predisposition and treatment of this thyroid disease. Diagnostic criteria for subacute thyroiditis were met in both twins, including hyperthyroxinemia, suppression of thyroidal 123I uptake, increased erythrocyte sedimentation rate, transient painful goiter, and absence of antimicrosomal antibodies. Twin B was treated with corticosteroids, and a nonsteroidal anti-inflammatory agent was prescribed for Twin A. The mode of treatment used did not make a difference in affecting the course of the disease. The erythrocyte sedimentation rate was normal after 2 months from onset of symptoms. Results of viral studies were inconclusive. The same HLA typing was found in each twin: A3, B18, B35, Cw4, DR2, DRw10, DQw1. Thus, each was heterozygous for HLA-B35. We reviewed the literature and found a strong association between HLA-B35 and subacute thyroiditis in various ethnic groups tested. Our experience with these identical twins provides additional evidence to suggest that HLA-35 and perhaps Cw4 confer genetic susceptibility in acquiring subacute painful thyroiditis in a possible dominant mode of inheritance.

Adult↗
PubMed1989

New perspectives in pheochromocytoma.

Pheochromocytomas are tumors that arise from chromaffin cells. Although the majority occur in the adrenal gland, these tumors can be found anywhere from the neck to the base of the pelvis. This condition, which is the cause of hypertension in only a small percentage of patients, can be cured in approximately 90 per cent of cases but can be lethal if left untreated. Pheochromocytomas may be familial in 10 per cent of patients, and in such cases, they may be associated with a variety of other conditions. The authors review the biochemical and radiologic diagnosis of adrenal and extra-adrenal tumors and discuss the treatment, including the special problems of pheochromocytoma during pregnancy.

Adrenal Gland Neoplasms↗
PubMed1987

Lymphocytic hypophysitis in a man.

Fewer than 20 patients with lymphocytic adenohypophysitis have been reported, all of them women, and it usually occurs during pregnancy or the postpartum period. We report the recognition of lymphocytic adenohypophysitis in a man. The patient presented with anterior hypopituitarism and an intrasellar mass on computed tomography. Antipituitary antibodies, found in only one of the previous patients, were not present in this man, although low titer antinuclear antibodies were found. The implications of this latter finding are unclear. The patient's histocompatibility antigen (HLA) types were A2, B8, Bw58, DR1, and DR5. The degree of pituitary failure seemed out of proportion to the size of the mass seen on computed tomographic scan.

Antibodies, Antinuclear↗
PubMed1986

An adrenocorticotropic hormone-producing pheochromocytoma: diagnostic and immunohistochemical studies.

A patient is described with Cushing's syndrome owing to a pheochromocytoma that was producing adrenocorticotropic hormone. Preoperative diagnosis was suggested by finding bilateral adrenocortical hyperplasia plus a separate unilateral adrenal medullary mass and was confirmed laboratory studies. Proper preoperative preparation was followed by a unilateral adrenalectomy and a clinical cure of both conditions. Immunohistochemical studies confirmed the ectopic production of adrenocorticotropic hormone and its related peptides more thoroughly than previous reports. The hormone production appeared clinically and immunocytochemically to resemble pituitary Cushing's disease more closely than ectopic production of adrenocorticotropic hormone by other tumors. The clinical aspects of this case illustrate the importance of proper preoperative recognition to reduce the high known percentage of morbidity and mortality.

ACTH Syndrome, Ectopic↗
PubMed1985

Familial ciliary dyskinesis: a cause of infertility without respiratory disease.

Two brothers were found to have primary infertility and nonmotile sperm secondary to ultrastructural defects, which included absent central doublets and peripheral microtubular translocation. No personal or family history of sinobronchial disease was obtained. Although sporadic cases of this type of ciliary dyskinesis have been reported, our patients constitute the first known occurrence of familial association.

Adult↗
PubMed1984

Primary intrasellar germinoma in a woman presenting with secondary amenorrhea and hyperprolactinemia.

A 32-year-old woman with secondary amenorrhea was found to have an elevated level of serum prolactin, partial diabetes insipidus, and a subtle visual field defect. A primary intrasellar tumor was noted on the computed tomographic scan. Although the tumor had some characteristics of a prolactinoma, transsphenoidal exploration revealed a primary germinoma. The tissue diagnosis led to appropriate treatment with radiotherapy. The tumor regressed, and the patient had a spontaneous pregnancy. Had dopamine agonists been used initially, amelioration of the hyperprolactinemia and delay in the proper diagnosis and treatment would have occurred.

Adult↗
PubMed1982

Secretion of prolactin after acute and chronic stimulation of the breast: effect of timing during the menstrual cycle.

The effect of acute and chronic stimulation of the breast was studied in 11 nonpostpartum women in both follicular and luteal phases of menstruation. In no subject did an increase in secretion of prolactin (PRL) result from either solitary or multiple episodes of stimulation of the breast over 24 hours. After 2 weeks of stimulation, three patients noted increased secretion; however, on rechallenge, this was found to be the result of testing in luteal versus follicular phase, rather than of the stimulation of breast itself. We concluded that breast stimulation, either acute or chronic, had no appreciable impact on secretion of PRL, but, rather, the phase of menstruation may influence basal secretion of PRL. Normal ranges may have to be recalculated to take this into account after larger numbers of women are studied.

Adult↗
PubMed1982

Concurrent production of adrenocorticotropin and prolactin from two distinct cell lines in a single pituitary adenoma: a detailed immunohistochemical analysis.

A pituitary tumor from a patient with severe Cushing's disease and marked hyperprolactinemia was extensively studied by immunohistochemical techniques. Tissues from two separate areas of the adenoma were found to contain similar cell proportions of PRL as well as ACTH and related peptides (beta-lipotropin, beta-endorphin, and alpha MSH). The tumor was composed of approximately 70% immunoreactive PRL cells and 5% ACTH-containing cells. Double immunostaining revealed that PRL or ACTH and related peptides were found in two distinct populations of tumor cells. These results document for the first time inappropriate synthesis and secretion of an unusual combination of pituitary hormones from a mixed pituitary adenoma.

Adenoma↗