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Biomedical subjects

A Beckers

Publications and source records attributed to A Beckers.

At least 19 recordsLinked to original sources
PubMed1995

The effect of naloxone and metoclopramide on the secretion of luteinizing hormone in a hyperprolactinemic hypogonadotropic postmenopausal woman.

OBJECTIVE: To determine the role of opioidergic and dopaminergic activity in the suppression of GnRH0LH in a hyperprolactinemic state. DESIGN: Case report. SETTING: University hospital. PATIENT: A 68-year-old woman with a macroprolactinoma. INTERVENTIONS: Serial 10-hour IV infusions of naloxone and metoclopramide. MAIN OUTCOME MEASURE: Serum LH concentration. RESULTS: Naloxone induced a small but significant rise of serum LH levels, which displayed a pulsatile pattern. By contrast, metoclopramide elicited no significant response in LH secretion. CONCLUSION: Opioidergic but not dopaminergic neurotransmission plays a direct role in the suppression of LH secondary to hyperprolactinemia.

Aged↗
PubMed1995

The prevalence of colonic polyps in acromegaly: a colonoscopic and pathological study in 103 patients.

Patients with acromegaly are reported to be at risk of developing adenomatous colonic polyps, which are considered to be preneoplastic lesions. This assumption is, however, usually drawn from results obtained in rather small series of patients or without a control group. We, therefore, undertook a prospective colonoscopic and pathological study comprising 103 acromegalic patients and 138 nonacromegalic control subjects referred for irritable bowel syndrome. The prevalence of adenomatous colonic polyps was significantly increased in acromegalic patients compared to that in control subjects (22.3% vs. 8.0%; P = 0.0024). The significance was similarly present in male acromegalic patients (28.6% vs. 5.5% in male control subjects; P = 0.0026), but was absent in female acromegalic patients. The prevalence of colonic polyps was also significantly increased in the group of acromegalic patients under 55 yr of age (20.0% vs. 3.0% in the control group of the same age; P = 0.0026). Other characteristics of adenomatous colonic polyps in acromegaly were the multiplicity and the presence proximal to the splenic flexure. No difference in the duration of acromegaly was found between patients with or without adenomatous polyps. The prevalence of hyperplastic colonic polyps was also significantly increased to 24.3% in acromegalic patients vs 4.4% in control subjects (P < 0.001). In conclusion, in view of the increased incidence of adenomatous colonic polyps, colonoscopy should be part of the follow-up examination in acromegaly.

Acromegaly↗
PubMed1994

Dramatic improvement of severe dilated cardiomyopathy in an acromegalic patient after treatment with octreotide and trans-sphenoidal surgery.

Severe congestive heart failure developed in an acromegalic patient, and was successfully treated with octreotide followed by trans-sphenoidal surgery. Clinical, hormonal echocardiographic and haemodynamic findings as well as histological heart examination before and after treatment revealed that over-production of growth hormone may induce the myocardial cell degeneration responsible for mechanical heart dysfunction. In addition, this unique example demonstrates the reversibility of myocardial damage following octreotide and trans-sphenoidal surgery, leading to significant improvement in cardiac function with minimal diastolic dysfunction and moderate interstitial fibrosis.

Acromegaly↗
PubMed1994

Variable regions of chromosome 11 loss in different pathological tissues of a patient with the multiple endocrine neoplasia type I syndrome.

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant inherited disorder characterized by nodular proliferation of the parathyroid glands and tumors of the anterior pituitary gland, the endocrine pancreas, and the neuroendocrine cell system of the gut. Loss of the putative tumor suppressor effect of the MEN1 gene is probably responsible for the development of MEN1-associated tumors. We report here a genetic study of a female MEN1 patient with the association of nodular hyperplasia of two parathyroid glands, an insulinoma, multiple duodenal gastrinomas, a prolactinoma, and a gastric carcinoid. We performed loss of heterozygosity (LOH) studies of chromosome 11 on all affected tissues except the insulinoma. Allelic losses of chromosome 11 were detected in several tumors, but the chromosomal regions of LOH were different, suggesting that different somatic mutational events are involved in the pathogenesis of these tumors. LOH of chromosome 11 was also detected in the prolactinoma of this patient, which indicates that the MEN1 gene has a tumor suppressor effect in the pituitary.

Calcium↗
PubMed1994

Autonomously functioning thyroid nodules in a patient with a thyrotropin-secreting pituitary adenoma: possible cause--effect relationship.

A 51-year-old female patient with long-standing hyperthyroidism due to a thyrotropin-secreting pituitary adenoma is reported, who became thyrotoxic again shortly after successful pituitary surgery. Functional testing and scintigraphy suggested the diagnosis of autonomous functioning thyroid nodules, which was confirmed by pathological examination of the resected thyroid tissue. This is the first report revealing the transition from a pituitary-dependent to a thyroid-dependent hyperthyroidism. Autonomous functioning thyroid nodules are, however, considered an intrinsic thyroid defect. In similarity with other disorders, in which trophic hormones may induce an autonomous secretion by the target gland, this report opens the possibility that a humoral factor may play a role in the development of autonomous functioning thyroid nodules.

Adenoma↗
PubMed1992

Contrast behavior between microadenoma and normal pituitary gland after gadolinium injection as a function of time at 1.5 T.

The behavior of contrast enhancement between a microadenoma and the normal pituitary gland after gadolinium injection was evaluated in 12 operatively confirmed cases using a repetitive sequence of four coronal T1-weighted spin echo series (T1 SE) (continuous acquisition, TR = 400 ms), followed by conventional coronal T1 SE (TR = 600 ms) and a three-dimensional fast low-angle shot sequence. The first and second acquisitions were useful with respect to delayed scans only in 3 cases (25%). Nevertheless, in these cases confident diagnosis could also be made on pre-contrast studies, which diminishes the real advantage of this finding. For a 1.5 T MRI unit we advocate starting with coronal T1 SE 30 s after a rapid injection of gadolinium.

Adenoma↗
PubMed1992

The association of astrocytoma and pituitary adenoma in a patient with alcaptonuria.

A female patient with a juvenile pilocytic astrocytoma and a pituitary adenoma is described. The patient also has alcaptonuria, a rare inborn error of metabolism with autosomal recessive mode of inheritance. The association of these three disorders has never been reported previously. The possible existence of a common genetic factor in the development of both tumors and alcaptonuria is discussed.

Adenoma↗
PubMed1992

Presurgical octreotide treatment in acromegaly.

The aim of this study was to determine the role of octreotide administration in acromegalic patients as a preparation for selective adenomectomy using transsphenoidal route. Octreotide was administered for 3 to 6 weeks before surgery in 12 patients and for 4 to 39 months in 25 patients. The clinical response was judged as excellent or good in 10 of 12 patients from group I and in 23 of 25 patients from group II. Marked reduction (ie, greater than 50% of initial values) in serum growth hormone (GH) levels was seen in all patients, with levels to less than 5 micrograms/L in 68% of patients and less than 2 micrograms/L in 27%. Insulin-like growth factor 1 (IGF-1) levels decreased to within normal limits in half the cases. During long-term treatment, an escape phenomenon could be seen. Varying degrees of tumor shrinkage were seen in more than 50% of cases. During surgery, with regard to the relative ease or difficulty in removing the tumor, the consistency of the tumor and the separation of normal from pathological tissue, no significant difference was observed between patients given octreotide and those from control series. Morphological changes in adenomatous tissue were rather small. The surgical outcome was similar in the pretreated series as in the control series, except in enclosed adenomas, which showed a tendency to a higher success rate. Since octreotide improves both the clinical condition and hormonal parameters and induces varying degrees of tumor shrinkage, it is potentially useful as an adjunct to surgery. Morphological data suggest that octreotide exercises a functional inhibitory effect on GH release.

Acromegaly↗
PubMed1992

Light and electron microscopic immunolocalization of bovine pregnancy-associated glycoprotein in the bovine placentome.

A bovine pregnancy-associated glycoprotein (bPAG) of 67 kDa has previously been isolated from bovine fetal cotyledons. The objective of this study was to determine the cytological localization of that protein in the placentomes and possibly the cells responsible for its production. Highly specific antisera raised against pure bPAG were used to demonstrate the cellular localization of the protein in bovine placentomes by light and electron microscopic techniques. Strong immunostaining was observed exclusively in the cytoplasm of large binucleate cells present predominantly in fetal cotyledonary tissue (villi). Some smaller weakly immunostained cells were also present in caruncular epithelium. By ultrastructural immunogold procedures, the protein was detected only within amorphous cytoplasmic granules. Granules of identical size, but weakly labeled, were found on the maternal side. All cells containing labeled granules were binucleate. These results suggest that bPAG is probably synthesized by trophoblast binucleate cells and stored in granules prior to delivery into the maternal circulation after cell migration.

Animals↗
PubMed1992

Treatment of macroprolactinomas with the long-acting and repeatable form of bromocriptine: a report on 29 cases.

Twenty-nine patients with macroprolactinomas were treated by monthly intramuscular injections of the long-acting and repeatable form of bromocriptine (Parlodel-LAR) in doses ranging from 50-150 mg. They were divided into two groups: group I consisted of 22 patients who received Parlodel LAR before transsphenoidal adenomectomy; group II was composed of 7 patients with earlier neurosurgery and of 2 patients from group I not cured by transsphenoidal adenomectomy. Duration of therapy varied from 1-12 months, and a total of 104 injections was given. At nadir day, serum PRL levels were situated between less than 1% and 43% of pretreatment values. At day 28 after the first injection, serum PRL levels varied between less than 1% to 139% of initial values. No difference could be detected between the two groups regarding the percent of PRL inhibition. Long-term treatment with Parlodel-LAR resulted in a sustained inhibition of PRL secretion, except for 1 case. Resumption of menstrual cycles occurred in 4 out of 15 women and correction of hypogonadism in 4 out of 14 men. Amelioration of disturbed visual fields was recorded in 3 out of 8 patients. Diminution of the adenoma volume was radiologically documented in 14 out of 22 cases. Only few and mild side effects were recorded. One patient with partial adrenal deficiency suffered from a syncope, but this was prevented by hydrocortisone supplementation during the subsequent Parlodel-LAR administration. In conclusion, Parlodel-LAR proved effective in the treatment of macroprolactinomas, achieving rapid inhibition of PRL secretion, and in some patients amelioration of hypopituitarism, reduction in tumor size, and improvement in visual fields, and caused no serious side effects. It is a valuable preparation to surgery and can also be used in long-term medical therapy.

Adult↗
PubMed1992

Aldosterone-secreting adrenal adenoma as part of multiple endocrine neoplasia type 1 (MEN1): loss of heterozygosity for polymorphic chromosome 11 deoxyribonucleic acid markers, including the MEN1 locus.

A 63-year-old female presented with the extremely rare occurrence of an aldosterone-secreting adrenocortical adenoma as part of the syndrome of multiple endocrine neoplasia type 1 (MEN1). Only two other MEN1 patients were reported in the literature with hyperaldosteronism. The patient's MEN1 syndrome consisted of the association of primary hyperparathyroidism due to parathyroid adenoma, a prolactinoma, and a toxic multinodular goiter. Elevated basal and meal-stimulated serum PP levels without demonstrable pancreatic tumor were also found. Genetic analysis of the aldosterone-secreting adenoma with DNA markers localized on chromosome 11 showed loss of heterozygosity in tumor DNA. Since the MEN1 syndrome is caused by loss of the tumor suppressor gene on chromosome 11 in the 11q13 region, it is probable that the same mechanism is associated with the formation of the adrenocortical adenoma.

Adenoma↗
PubMed1991

Acute effects of Parlodel-LAR and response to long-term treatment with bromocriptine in a patient with a follicle stimulating hormone-secreting pituitary adenoma.

A 68-year-old male patient presented with visual impairment due to a large pituitary tumor. After transsphenoidal adenomectomy the elevated serum FSH levels were lowered but not normalized. Deterioration of the vision was detected five years later and tumor regrowth was evidenced. The patient was treated with the long-acting and repeatable form of bromocriptine (Parlodel-LAR). Three days after the first intramuscular injection it already resulted in an important improvement of the visual field defects. Serum FSH concentration was suppressed during a prolonged period, but no change in the size of the pituitary adenoma was recorded on CT scan. Long-term oral treatment with bromocriptine resulted in a sustained suppression of the serum FSH levels, without further visual improvement, but with a significant reduction of the volume of the adenoma. The rapid and prolonged effect of Parlodel-LAR upon the FSH secretion, with a possible correction of the visual field defects and a reduction of the tumor mass, could make this medication appropriate as adjunctive treatment in some gonadotroph cell adenomas.

Adenoma↗
PubMed1991

Cyclical Cushing's disease. A case report.

A 41-year-old man with clinical Cushing's syndrome and intermittent central ACTH hypersecretion for a period of 9 1/2 years follow-up is described. Episodes of biochemical and clinical remission alternated with periods of florid Cushing's disease, characterized by circadian hyperpulsatile ACTH and cortisol secretion. Responses to metyrapone and inhibition of ACTH and cortisol hypersecretion after high dose dexamethasone during active phases of the disease favored a central origin of ACTH hypersecretion, confirmed by simultaneous bilateral venous sampling of the sinus petrosus inferior. Prolonged clinical remission followed near total anterior hypophysectomy. However, on anatomopathological examination of the pituitary neither corticotroph cell hyperplasia nor a microadenoma could be documented. The possibility of a functional ACTH hypersecretion is discussed.

Adrenal Glands↗
PubMed1991

Immunocytochemical evidence for production of luteinizing hormone and follicle-stimulating hormone in separate cells in the bovine.

In all mammalian females, follicular growth and maturation are essentially dependent on the pituitary gonadotropins, FSH and LH. These glycoprotein hormones have many similarities, but their action, based on high affinity binding to specific membrane receptors, are quite different. The purpose of this study was to perform a sensitive localization of FSH and LH in secretory granules of gonadotrophs using highly specific antisera. This morphological study included light microscopy (PAP) and electron microscopy (immunogold single and double labeling) procedures. Histologically, approximatively 11.5% of cells were positive for LH, whereas only 5.4% of cells were positive for FSH. With the electron microscope, single labeling allowed identification of morphologically distinct LH-containing cells and FSH-containing cells. Double immunostaining confirmed that no cells contained both hormones. The finding that FSH and LH are produced in separate pituitary cells is in agreement with recent studies that have suggested a specific role and regulatory process for gonadotropins in the bovine species.

Animals↗