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Biomedical subjects

H Beauregard

Publications and source records attributed to H Beauregard.

At least 37 records · Page 2Linked to original sources
PubMed1988

Low serum urea level in dehydrated patients with central diabetes insipidus.

Dehydrated patients usually present with an elevated serum urea level, owing in part to increased renal reabsorption of urea mediated by antidiuretic hormone (ADH). We carried out a study to examine whether, during dehydration, the variations in the serum urea level could discriminate patients with central diabetes insipidus (CDI) from those with dehydration not due to CDI. We studied retrospectively 27 episodes of dehydration in 23 patients with CDI and 14 episodes in 14 patients without CDI. The mean serum urea level was 2.9 mmol/L in the CDI group and 15.4 mmol/L in the patients without CDI (p less than 0.001); the mean serum sodium level was 155 mmol/L in both groups. All the patients with CDI had a sodium/urea ratio greater than 24.2, whereas the ratio was less than 21.7 in all the patients without CDI. In the patients with CDI a positive correlation was found between the magnitude of diuresis and the percentage decrease in the serum urea level compared with the level before dehydration (p less than 0.001). In the patients with CDI the serum urea level returned to the level before dehydration after the administration of vasopressin; a striking increase in the clearance of urea, which exceeded the creatinine clearance, was observed during dehydration in the three patients in whom clearance studies were done. The results suggest that serum urea values can be used to distinguish patients dehydrated because of CDI from those with hypertonic dehydration but without ADH deficiency and that during dehydration the net reabsorption of urea is dependent on the renal action of ADH.

Adult↗
PubMed1988

Defective dopaminergic regulation of prolactin secretion in patients with hyperprolactinemia.

In order to evaluate the dopaminergic control of the lactotroph, we examined the plasma prolactin response to metoclopramide (a dopamine receptor blocker, 10 mg iv bolus) and to dopamine (1 microgram/Kg/min iv infusion for 120 min) in 52 hyperprolactinemic female patients and 19 healthy volunteer women. Three diagnostic categories were included: "idiopathic" hyperprolactinemia (21), microadenoma (24), and macroadenoma (7). Patients from all groups showed a marked blunting of the prolactin response to metoclopramide as compared to the prolactin rise in normal women (p less than 0.001). However, normal responses were observed in 8 patients with idiopathic hyperprolactinemia and in one patient with adenoma. The magnitude of the prolactin response to metoclopramide (percent of baseline level) correlated negatively with the level of basal prolactin in each group except for macroadenoma patients. Dopamine infusion significantly (p = 0.015) reduced the mean plasma prolactin levels in hyperprolactinemic patients and normal women. However, patients with idiopathic hyperprolactinemia were hyposensitive to dopamine (p less than 0.05). Furthermore, microadenoma patients were less responsive to dopamine suppression than were the patients with macroadenoma (p less than 0.05). The results indicate the presence of a relative resistance to dopamine in patients with idiopathic hyperprolactinemia and in patients with microadenoma. They also suggest that in these patients, the decrease in prolactin response to metoclopramide may be explained by the relative refractoriness to endogenous dopamine.

Adenoma↗
PubMed1987

Hyperprolactinemia associated with clinically silent adenomas: endocrinologic and pathologic studies; a report of two cases.

Pituitary adenomas containing adrenocorticotropic hormone (ACTH) in one case, and ACTH, beta-lipotropin, and beta-endorphin in the other, were demonstrated in two patients who had amenorrhea-galactorrhea and hyperprolactinemia with no manifestation of Cushing's disease. Neither adenoma contained prolactin (PRL). Initial bromocriptine therapy resulted in cessation of amenorrhea-galactorrhea and normalization of PRL levels. However, there was radiologic evidence of tumor enlargement in both patients. After pituitary adenomectomy, the two patients resumed regular menses and normal PRL dynamics. These patients illustrate the need for bromocriptine therapy for possible enlargement of their pituitary adenomas. The diagnosis of silent corticotroph adenoma should be kept in mind.

Adenoma↗
PubMed1987

Distinctive features of prolactin secretion in acromegalic patients with hyperprolactinaemia.

We have investigated the relationship between the plasma PRL concentrations of 98 untreated acromegalic patients and the GH levels during basal and dynamic conditions. Hyperprolactinaemia was present in 27 patients. In patients with marked hyperprolactinaemia (PRL greater than 80 ng/ml or greater than 1600 mU/l), basal plasma PRL and the TRH-induced response correlated with basal plasma GH (correlation coefficients of 0.9, P less than 0.001 and 0.74, P less than 0.02, respectively). The PRL response to TRH also correlated with GH response to TRH (r = 0.38, P less than 0.01). In contrast, in patients with moderately elevated PRL (20 to 80 ng/ml), and in those with normal plasma PRL (less than 20 ng/ml or less than 400 mU/l), no such correlations were found. Immunostaining for PRL was positive in 24 out of 25 adenomas of patients with hyperprolactinaemia, while no PRL was found in the tumour tissue of 10 normoprolactinaemic patients. In conclusion, our data suggest the existence of two populations of acromegalic patients with hyperprolactinaemia, one group with correlations between GH and PRL secretion, and the other without.

Acromegaly↗
PubMed1986

Decreased sensitivity to insulin in women with microprolactinomas.

To determine whether there exists an altered sensitivity to insulin in hyperprolactinemia, we studied, in 15 women with microprolactinomas, the insulin effects on glucose, PRL, GH, and cortisol before and after successful adenoma removal. Our results show that in women with microprolactinomas, the sensitivity to insulin is lower in hyperprolactinemia than in normoprolactinemia achieved by selective adenomectomy.

Adenoma↗
PubMed1986

Capnocytophaga ochracea and group F beta-hemolytic streptococcus suppurative thyroiditis.

The route of infection in acute suppurative thyroiditis is unknown in most cases; when demonstrated, pyriform sinus fistula appears to be the most frequent one. We report the clinical and laboratory findings of a child in whom culture of the thyroid pus yielded two bacteria which are part of the normal oropharyngeal flora: capnocytophaga ochracea and group F Beta-hemolytic streptococcus. The preliminary results of the culture, which showed a mixed flora, prompted us to search and to find a pyriform sinus fistula. Apart from the onset in infancy, the left lobe involvement and the frequent recurrence, the recovery from the thyroid pus of bacteria from normal oropharyngeal flora should be included in the characteristic features of thyroiditis resulting from an infection through the pyriform sinus fistula.

Adolescent↗
PubMed1985

Acromegaly: biochemical assessment of cure after long term follow-up of transsphenoidal selective adenomectomy.

This study reports the clinical and biological follow-up 5-11 yr after transsphenoidal selective adenomectomy in 25 patients with acromegaly. Eight patients had microadenomas, and 17 had macroadenomas. Initial normalization of plasma GH levels (basal values, less than 5 ng/ml; glucose-suppressed concentrations, less than 2.5 ng/ml) was achieved in all 8 patients with microadenomas and in 13 patients with macroadenomas. Of these, 3 patients with normal GH levels and dynamics had relapse of GH hypersecretion after intervals between 1-6 yr after microadenoma removal. Recurrence of pituitary adenoma was documented by surgery in 1 patient and by computed tomographic scanning in 2 others. Normal basal and glucose-suppressed plasma GH concentrations were maintained 7.4 +/- 0.5 (+/- SEM) yr after adenomectomy in 7 patients with microadenomas and in all 10 patients with macroadenomas. Thus, 88% of the patients with microadenomas and 59% of the patients with macroadenomas were cured, and the overall cure rate was 68%. We conclude that recurrence of acromegaly after successful surgery may occur late after adenoma removal and that it cannot be predicted by normal postoperative GH levels and dynamics. However, in view of the overall cure rate, transsphenoidal adenomectomy remains a most valuable treatment for acromegaly.

Acromegaly↗
PubMed1983

Recurrence of hyperprolactinemia after selective transsphenoidal adenomectomy in women with prolactinoma.

To assess the long-term prognosis for women with prolactinoma after selective transsphenoidal adenomectomy, we followed 44 patients for 6.2 +/- 1.5 years. Group 1 (28 patients) had microprolactinomas, and Group 2 (16 patients) had macroprolactinomas. After surgery, normal plasma prolactin levels, resumption of menses, and cessation of galactorrhea were observed in 24 Group 1 patients (85 per cent) and 5 Group 2 patients (31 per cent). Hyperprolactinemia recurred in 12 of the 24 Group 1 patients and in 4 of the 5 Group 2 patients after 4 +/- 1.3 and 2.5 +/- 1.6 years of remission, respectively. There was no radiologic evidence of tumor recurrence in any patient, and no relation was found between the occurrence of pregnancy after surgery and the recurrence of hyperprolactinemia. Clinical and biologic features before surgery could not predict the long-term outcome. However, the immediate postoperative level of plasma prolactin was significantly lower in patients in whom normal prolactinemia (6.4 +/- 1.1 ng per milliliter) was maintained than in those who relapsed (11.7 +/- 1.5 ng per milliliter) (P less than 0.02). We conclude that recurrence of hyperprolactinemia after successful surgery is frequent but delayed. The immediate postoperative level of plasma prolactin may be a predictive risk factor.

Adenoma↗
PubMed1982

Oral contraceptives and prolactinomas: a case-control study.

The increase in the number of newly diagnosed cases of prolactinomas seems to coincide with the use of oral contraceptives during the past two decades. The following retrospective case-control study was undertaken in an attempt to disprove a null hypothesis of relationship between oral contraceptive use and prolactinomas. Each of 70 patients operated upon for removal of a prolactinoma was closely matched for age, gravidity, and year of final diagnosis with one patient in each of three control groups. The control groups selected were constituted, respectively, of patients with secondary amenorrhea and normal prolactin levels, patients with normal ovulatory cycles consulting for infertility, and subjects without medical or gynecologic problems. No statistically significative differences were found in the exposure rates to oral contraceptives among four groups. This study thus failed to reveal a significant association between prolactinomas and oral contraceptives but, given the sample size, a relative risk lower than 3.32 cannot be demonstrated or disproved.

Adolescent↗
PubMed1981

[Prolactinoma in the male. Preoperative evaluation of 40 patients].

Forty male patients with a prolactinoma were studied. The majority of tumors were large. Eight (20%) were microadenomas. Loss of libido and sexual impotence, the most frequent symptoms, were found in 82,5% of cases. Gynecomastia with galactorrhea was noted in six cases. Seven patients had hypopituitarism and nine visual field defects. Prolactin levels ranged from 30 to 7,000 ng/ml. The mean baseline prolactin value was higher in the group of invasive adenomas or enclosed adenomas with a suprasellar expansion. The LH-RH test, performed on twenty-eight patients, showed an abnormal response in 80% of the cases.

Adenoma↗
PubMed1981

[Prolactinoma in the male. Therapeutic results in 40 men].

Forty male patients with a prolactinoma were operated on by the transsphenoidal approach. Postoperative normalization of PRL levels occurred in 37% of the cases, in 100% of the microadenomas and 68% of the adenomas with preoperative PRL levels below 700 ng/ml. None of the invasive tumors were normalized. Partial hormonal deficits were produced by surgery in three cases and panhypopituitarism in one case.

Adenoma↗
PubMed1980

ACTH-secreting medullary carcinoma of the thyroid: monitoring of clinical course with calcitonin and cortisol assays and immunohistochemical studies.

The clinical course of a patient with Cushing's syndrome secondary to metastatic medullary carcinoma of the thyroid was documented with serial calcitonin and cortisol assays and tumor immunohistochemistry studies. Cortisol levels were originally markedly elevated but returned to normal after total thyroidectomy. These levels rose again when the patient developed liver metastases but normalized during chemotherapy, never to rise again despite the appearance of cervical lymph node metastasis. Calcitonin levels remained elevated throughout the course. The original tumor was composed of two cell lines: one containing both calcitonin and ACTH and another containing only calcitonin-reacting cells. However, the cervical metastasis showed a marked decrease in both cell lines with fever than 1% of cells reacting to ACTH, and only 25% to calcitonin. The almost total disappearance of ACTH-reacting cells may have been therapeutically induced or may represent a consequence of tumor progression.

Adrenocorticotropic Hormone↗
PubMed1980

Prolactin-secreting pituitary adenomas in males: transsphenoidal microsurgical treatment.

Fifteen male patients with prolactin-secreting pituitary adenomas were studied before and after transsphenoidal microsurgical treatment. Loss of libido and sexual impotence were the most frequent symptoms, being present in 12. Visual defects were present in seven patients, gynecomastia was observed in four and galactorrhea was noted in three. Most of the tumours were large; only one was a microadenoma. Four patients were cured by the operation. In all the other patients the plasma levels of prolactin were significantly lowered and the visual defects corrected or lessened, but sexual impotence was not modified. No important deficiency of the pituitary gland was induced by the operation. The results indicate that in males loss of libido and sexual impotence are frequent and early manifestations of prolactinomas, and that transsphenoidal resection is a safe therapeutic approach.

Adenoma↗