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Biomedical subjects

A Beckers

Publications and source records attributed to A Beckers.

At least 19 recordsLinked to original sources
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↗
PubMed1991

Thyrotropin-secreting pituitary adenomas: report of seven cases.

Seven patients with hyperthyroidism due to a TSH-secreting pituitary macroadenoma have been observed of a total of 800 patients with pituitary tumors over a period of 15 yr. Serum TSH levels varied between 1.1-36.3 mU/L. The serum alpha-subunit level was low in 1 case, while in 4 other cases the concentration was elevated and varied between 3.7-7.8 micrograms/L. Serum TSH beta levels were normal in the 4 cases in which it was determined. Serum GH or PRL levels were elevated in 5 cases. In 1 patient the cosecretion of TSH, GH, and PRL was confirmed by immunocytochemical examination. Serum TSH and alpha-subunit responses to TRH, GnRH, CRF, GRF, dexamethasone, methimazole, T3, and bromocriptine administration were variable when studied. Serum TSH and alpha-subunit circadian rhythms were absent in 1 case and inverted in another. A serum alpha-subunit pulsatility without TSH pulses was observed in 1 patient. Five patients underwent transsphenoidal adenomectomy. Three of 4 patients operated on in our center were cured, but a recurrence of the adenoma was found in 1 of them after 5 yr. The fifth patient was not cured. Treatment with octreotide in 3 patients resulted in normalization of serum TSH, GH, and thyroid hormones levels. Cosecretion of PRL in 1 case and alpha-subunit in 2 cases was also inhibited. Partial tachyphylaxis occurred in 1 patient. In summary, heterogeneity in clinical presentation, hormonal expression, and therapeutic response appears to characterize these TSH-secreting adenomas.

Adenoma↗
PubMed1991

Adenohypophysis hormone gene products in 14 pituitary adenomas: analysis by immunohistochemistry and northern blotting.

We investigated 14 pituitary adenomas (10 silent adenomas; 3 prolactinomas and one GH-secreting tumor) for the presence of hormone gene transcripts (Northern blot) as well as for translation products (immunohistochemistry). The GH-secreting tumor was shown to express the genes coding for GH and PRL and to synthesize the corresponding hormones. In the cases of prolactinomas, immunohistochemical data demonstrated the synthesis of prolactin only. In addition to the PRL gene, Northern blot analysis revealed the transcription of the alpha-subunit gene in one case. Hormone genes were found to be expressed in 7 out of the 10 silent tumors, whereas no hormone synthesis was detected in any of these tissues. LH-beta mRNA was found in 3 cases, FSH-beta mRNA in 5 cases and alpha-subunit gene was shown to be expressed in one case. Surprisingly, the level of expression of the FSH-beta gene was higher than in normal tissue. This study confirms that some so called "silent" adenomas are expressing alpha- and/or beta-subunit glycoprotein hormone genes, even if no hormone is synthesized. The therapeutic action of bromocriptine described in some "silent" adenomas cases could be related to that hormone gene expression potentiality.

Adenoma↗
PubMed1990

Acromegaly, multinodular goiter and silent polyostotic fibrous dysplasia. A variant of the McCune-Albright syndrome.

A 36-year-old woman is reported with a possible variant of the McCune-Albright syndrome. The triad was incomplete because of the absence of skin pigmentation and since the sexual precocity was not evident. The presence of a pituitary mass and the secretory dynamics of growth hormone and prolactin were suggestive of a mammosomatotroph cell adenoma. A toxic multinodular goiter was also associated, but unique was the spontaneous normalization of the thyroid function. Unusual was the silent evolution of the polyostotic fibrous dysplasia, which was only fortuitously discovered during magnetic resonance imaging of the pituitary region. Treatment of the acromegaly with the long-acting somatostatin analogue octreotide resulted in an important inhibition of the GH secretion and in a reduction of the volume of the pituitary adenoma.

Acromegaly↗
PubMed1990

Cyclical Cushing's disease and its successful control under sodium valproate.

Several subgroups of Cushing's disease were recently described (anterior or intermediate lobe origin, hyper-or hypo-pulsatility of cortisol, presence or absence of response after GRH or TRH, cyclical Cushing's disease). We present here a detailed case report on a patient suffering from Cushing's disease whose endocrine functions were extensively investigated. Treatment with bromocriptine, as well as subsequent transsphenoidal surgery, were followed by rapid but transient reversal of symptoms. When clinical manifestations reoccurred, daily measurements of free urinary cortisol revealed a cyclic pattern of cortisol hyperexcretion. A study of ultradian rhythm revealed hyperpulsatility of cortisol secretion. More interestingly, a treatment with sodium valproate, a drug known to inhibit CRH production, was followed by a rapid and longstanding normalization of clinical and biological data for 2 years. Based on these data, and on information from the literature, the present case of Cushing's disease exhibits characteristics suggesting a possible hypothalamic origin.

Adolescent↗
PubMed1990

Pituitary microadenomas: diagnosis with two-and three-dimensional MR imaging at 1.5 T before and after injection of gadolinium.

The usefulness of different magnetic resonance (MR) imaging sequences (coronal and sagittal spin-echo [SE] and three-dimensional fast low-angle shot [3D FLASH]) in the detection of pituitary microadenomas before and after gadolinium injection was prospectively evaluated in 28 patients with surgical confirmation. When evaluated separately, the most useful sequences in the detection of these microadenomas were coronal pregadolinium T1-weighted SE, coronal pregadolinium 3D FLASH, coronal postgadolinium T1-weighted SE, and coronal postgadolinium 3D FLASH. The combination of pre- and postgadolinium T1-weighted sequences with pre-and postgadolinium 3D FLASH sequences produced the highest number of true-positive findings (90%) and the lowest number of false-positive findings (5%). When a 1.5-T imaging unit with a high signal-to-noise ratio allowing useful three-dimensional acquisition is used, the authors advocate a coronal T1-weighted SE sequence, followed (if necessary) by a coronal 3D FLASH sequence, both without injection of gadolinium, in the diagnosis of pituitary microadenomas. When no confident diagnosis is reached, the same sequences should be performed after the injection of gadolinium. The sagittal pre- and postgadolinium T1-weighted SE and long-TR SE sequences are useful only in specific cases.

Adenoma↗
PubMed1990

Perinatal growth hormone (GH) physiology: effect of GH-releasing factor on maternal and fetal secretion of pituitary and placental GH.

To study regulation of the secretion of human pituitary GH (hGH) and placental GH (hPGH) in the pregnant woman and human fetus, the GH-releasing factor Sermorelin [GRF-(1-29)-NH2] was administered to pregnant women at term (n = 5), just before elective cesarean section; saline was administered in control studies (n = 5). The effects of GRF-(1-29)-NH2 administration on maternal and fetal serum concentrations of hGH and GRF-(1-29)-NH2 and maternal serum levels of hPGH were evaluated at birth. The mean time span between injection and birth was 20 min (range, 15-25 min). Cord serum hGH concentrations were similar in infants of GRF-(1-29)-NH2-injected mothers and control infants. GRF-(1-29)-NH2 elicited a consistent but small rise in maternal hGH serum concentrations (P = 0.08), whereas hPGH concentrations remained unaltered. Finally, GRF-(1-29)-NH2 concentrations were undetectable in cord serum, but readily detectable in concomitantly obtained maternal serum. In conclusion, these data suggest that hGH secretion in the pregnant woman at term is suppressed at the pituitary level, that GRF does not affect hPGH secretion, and that fetal hGH secretion is independent of circulating maternal GRF, probably because of lack of transplacental GRF passage.

Cesarean Section↗
PubMed1990

Placental and pituitary growth hormone secretion during pregnancy in acromegalic women.

It is now well established that during the second half of normal pregnancy, the human placenta secretes its specific GH variant (placental GH) in increasing amounts up to delivery. During the same period, pituitary GH secretion is progressively suppressed. The present study was aimed at clarifying the physiology of GH secretion in pregnant acromegalic women. Two young women remained acromegalic despite transphenoidal removal of their pituitary adenoma. Increased basal levels of GH and insulin-like growth factor-I (IGF-I) as well as paradoxical GH release after TRH injection were noted. Both women became pregnant and delivered term babies without any complication. In both patients, pituitary GH remained elevated during the entire pregnancy, contrary to the situation in normal women. Paradoxical GH release after TRH treatment was also present, whereas no response was observed in five normal control subjects. GH pulsatility studies revealed a highly pulsatile secretory pattern of pituitary GH, in contrast to that in normal woman, whose placental GH is secreted tonically. Tissue placental GH concentrations were within the range of levels in normal placentas. An increase in serum IGF-I in late pregnancy was also similar to that observed in normal pregnancy. These findings confirm that increased IGF-I levels are not pituitary GH dependent in late pregnancy. They add new evidence that adenomatous somatotrophs lack an IGF-I-dependent feedback regulation present in normal somatotrophs.

Acromegaly↗
PubMed1989

Vestibular habituation training for positional vertigo in elderly patients.

Positional vertigo can be successfully treated by exercises (Vestibular Habituation Training, VHT) in elderly patients as well as in younger ones. Provided the patients have been correctly selected, this type of treatment is the only way for an adequate treatment of such a type of vertigo. Application of VHT has to be recommended also in elderly people, as the results obtained are as favourable as those in younger people. Only a slower evolution is observed, which can be correlated with a more restricted activity pattern in the elderly.

Adult↗