Search PubMed⌕ Search

Biomedical subjects

G Benker

Publications and source records attributed to G Benker.

At least 91 records · Page 5Linked to original sources
PubMed1986

Diagnostic criteria in pituitary tumour recurrence--combined modality of surgery and radiotherapy.

The tumour recurrence rate of 210 patients with operated hypophysomas were investigated. Depending on the surgical approach, total or subtotal extirpation of the adenomas, the recurrence rates varied from 10,4 to 35%. 33 patients with pituitary tumour recurrences were followed up over a period of 20 years. Clinical symptoms CT-results at relapse are represented. Serum prolactin level (PRL) was determined before and after surgical and radiotherapy of PRL-producing adenomas. In these cases PRL can be accepted as a tumour marker. 13 patients with relapsed hypophysomas received local irradiation (5.7 MeV linear accelerator) after recurrence operation. An individual comparison in the same patient between surgical therapy alone and combined surgical and radiotherapy was possible. Based on the obtained experience with this combined treatment a therapy scheme using combined surgery and radiotherapy in pituitary tumours is suggested.

Adenoma↗
PubMed1986

Parenteral bromocriptine in the treatment of hormonally active pituitary tumours.

Eleven patients with PRL and three with GH-secreting pituitary adenomas were treated with a single intramuscular injection of 50 mg of bromocriptine retard (Parlodel, LA (long-acting)). There was a marked PRL suppression in 9 prolactinoma patients, in four for a period of at least 6 weeks. In one patient with acromegaly GH plasma levels decreased into the normal range. The size of the pituitary adenoma diminished considerably, as shown by CT scan, in three out of the 9 responding patients with prolactinoma and in the above acromegalic patient. Visual fields normalized within 14 d in one patient with a PRL-secreting macroadenoma and bitemporal hemianopsia who also had CT scan-documented shrinkage of the tumour. There were no side-effects except slight hypotension in two and local tenderness at the injection site in one patient; these symptoms disappeared without treatment. It is concluded that bromocriptine retard is a safe and effective therapeutic tool for shrinking hormonally active pituitary tumours in selected patients. Due to its good tolerance and the rapid hormonal and clinical improvement it may be also considered as the best therapeutic approach to initiate the treatment of PRL- and/or GH-secreting pituitary tumours.

Acromegaly↗
PubMed1986

Continuous infusion of growth hormone releasing hormone does not alter the growth hormone response to different stress stimuli.

Continuous infusion of GHRH, as well as a bolus injection of GHRH, specifically stimulates the release of GH by the anterior pituitary. However, repetitive bolus injections of GHRH result in diminished responses of GH, while a constant infusion of GHRH cannot maintain high serum GH levels. To investigate whether different GH-releasing stimuli are able further to challenge the somatotroph being exposed to continuous infusion of GHRH, we determined the GH response to insulin-induced hypoglycaemia and bicycle exercise. Six normal volunteers received a bolus of 50 micrograms GHRH or vehicle followed by a continuous infusions of GHRH 1-29 amide (1 microgram/kg/h) or vehicle for 2.5 h. GHRH bolus and infusion resulted in elevated GH levels, but GH levels fell to values not significantly different from baseline levels after 150 min, GH plasma levels rose again, however, in response to insulin hypoglycaemia and bicycle exercise after both GHRH or vehicle infusion. Thus, the somatotroph's responsiveness to GHRH remains intact to respond to stress stimuli after continuous GHRH infusion.

Adult↗
PubMed1986

Corticotropin-releasing hormone (CRH) stimulation in Nelson's syndrome: response of adrenocorticotropin secretion to pulse injection and continuous infusion of CRH.

Nelson's syndrome develops in 10-15% of patients with Cushing's disease who undergo bilateral adrenalectomy. Whether the pituitary tumors of Nelson's syndrome are autonomous or are regulated by hypothalamic signals or glucocorticoids is controversial. We, therefore, compared the plasma ACTH responses to synthetic ovine corticotropin-releasing hormone (CRH) in 11 patients with Nelson's syndrome, 1 patient with Cushing's disease who had had bilateral adrenalectomy and did not have Nelson's syndrome, 14 patients with Cushing's disease, and 27 normal subjects. The plasma ACTH response to CRH in 10 patients with Nelson's syndrome was markedly increased and prolonged compared to the responses of normal subjects or patients with Cushing's disease. In 4 patients with Nelson's syndrome, plasma ACTH and cortisol concentrations also were determined at frequent intervals for 10-24 h during continuous infusions of 0.15 M saline or CRH (1 microgram/kg X h). There was no desensitization of ACTH secretion during short term continuous infusion of CRH. Exogenous cortisol inhibited CRH-stimulated ACTH secretion. These findings suggest that the ACTH response to CRH of patients with ACTH-secreting tumors of Nelson's syndrome differs from the response of those who have the microadenomas of Cushing's disease in two ways: the magnitude is greater, and the response is prolonged. These differences can be explained by the greater size of the tumor and the reduced glucocorticoid feedback in adrenalectomized patients with Nelson's syndrome.

Adolescent↗
PubMed1986

Response of total and 'free' thyroid hormones and diiodotyrosine to bovine TSH in subclinical hypothyroidism.

Thirty-three patients with Addison's disease were studied. Twenty-two had idiopathic Addison's disease; within this group, 14 patients had clinical or subclinical hypothyroidism, and 16 had increased titres of thyroid autoantibodies. Five patients had tuberculous, and eight had unclassifiable Addison's disease; only one patient in the latter group had evidence of thyroid autoimmunity. A stimulation test with 15 mU bTSH/kg was performed in three patients with Schmidt's syndrome (coexisting Addison's disease and manifest primary hypothyroidism), 15 patients with either subclinical hypothyroidism or increased titres of thyroid autoantibodies, 10 patients without thyroid involvement, and 10 normal controls. There was no detectable increase of 'free' and total thyroid hormones in Schmidt's syndrome. The mean increases after 3-4 h of T4, fT4, T3 and fT3 were 22, 35, 63 and 66%, respectively, in patients without thyroid involvement, and 13, 24, 46 and 45% in patients with subclinical hypothyroidism. 'Free' but not total thyroid hormones rose significantly (P less than 0.01) higher in patients without signs of thyroid involvement than in patients with subclinical hypothyroidism and/or thyroid autoantibodies. Thyroid hormone response to bTSH in Addison's disease with apparently healthy thyroid glands was not different from normal controls. Serum diiodotyrosine rose in all groups except in hypothyroidism; hypothyroid patients had, however, basal levels well within the normal range. Thus, thyroid hormone synthesis appears to be blocked at a point distal to diiodotyrosine formation in this particular situation. These results support the assumption that TSH elevation in idiopathic Addison's disease is due to coexisting thyroid autoimmunity and that it reflects incipient thyroid failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Addison Disease↗
PubMed1985

[Sonographic volumetry of the thyroid gland in the control o thyroxin and iodide treatment of non-toxic goiter].

In a prospective study 39 patients with diffuse euthyroid goitre were treated for one year with 100 micrograms levothyroxine (n = 19) or 500 micrograms iodide (n = 20). Efficacy of treatment was assessed by sonographic thyroid volumetry . In both forms of treatment maximum volume decrease was already seen within the first six months. After treatment for one year the mean decrease of thyroid volumes was 27.5% in the thyroxine group and 22% in the iodide group. This difference was statistically not significant. There was no difference in the extent of goitre size reduction within the thyroxine group among patients with complete TSH suppression and with still positive TRH test. Significant increases of T4 and of fT4 values within the normal range were observed already after one month with thyroxine treatment and only after 3 months with iodide treatment. There were no changes of the T3 values. In one female patient iodine-induced hyperthyroidism occurred. However, there were no further side effects in both treatment groups. This randomised study documents for the first time that both 500 micrograms of iodide and 100 micrograms of levothyroxine have a comparable efficacy for reduction of goitres.

Adolescent↗
PubMed1985

[Sonography of the neck in hypercalcemic crisis].

In hypercalcaemic crisis sonographic identification of an enlarged parathyroid permits the indication for parathyroidectomy. This is particularly important as determination of the parathormone concentration to find out the cause of hypercalcaemia takes too long and thus delays diagnosis and therapy. In two patients with symptoms of crisis successful parathyroidectomy was performed solely on the basis of a raised serum calcium concentration and a sonographically proven enlarged parathyroid.

Acute Kidney Injury↗
PubMed1985

Failure to respond to growth hormone releasing hormone (GHRH) in acromegaly due to a GHRH secreting pancreatic tumor: dynamics of multiple endocrine testing.

Growth hormone releasing hormone (GHRH) has recently been isolated and sequenced from pancreatic tumors secreting GHRH. Patients with untreated acromegaly due to a pituitary tumor respond to exogenous administration of GHRH with a further rise of their elevated basal growth hormone (GH) levels. For the first time, we report the effects of exogenously administered synthetic GHRH in a patient with acromegaly due to a GHRH secreting pancreatic tumor. The diagnosis was established by high peripheral IR-GHRH levels (1100 pg/ml) and an arterio- venous tumor gradient of IR-GHRH. In this patient GH failed to respond to 1 microgram/kg of exogenous GHRH with the pancreatic tumor in situ; however, further increase of serum GH levels occurred after TRH administration, hypoglycemia and oral glucose administration. After removal of the tumor, serum GH levels decreased and a normal response to GHRH and TRH were demonstrated. The extract of the tumor contained 1.7 micrograms IR-GHRH per g wet tissue. Thus, lack of response to exogenous GHRH in untreated acromegaly may indicate the presence of an ectopic GHRH producing tumor.

Acromegaly↗
PubMed1985

Effects of small doses of bovine TSH on serum levels of free and total thyroid hormones, their degradation products, and diiodotyrosine.

Bovine TSH was administered iv to 10 normal volunteers in doses of 2.5, 7.5, 15 and 30 mU/kg. Brisk elevations of serum diiodotyrosine occurred already after the smallest dose (mean, +183%) while larger doses had only slight additional effects. T3 rose much higher than T4 (+71% compared to +23% after 15 mU bTSH/kg), and free thyroid hormones exhibited changes similar to total T3 and total T4. The mean absolute increase in serum fT3 ranged from 2.03 to 9.04 pmol/l and proved to be an easily measurable parameter for the TSH effect. Dose-response effects were seen for the increase of fT4, fT3 and T3. TBG and rT3 did not change but the degradation product 3,3'-T2 showed large increments of serum levels. There was no correlation between the response of T3 and T4, fT3 and fT4, or diiodotyrosine and any of the other parameters of thyroid function. The interindividual differences in the magnitude of thyroid hormone response to TSH were considerable, and there was no relationship between this response and thyroid volume by ultrasound. We conclude that direct stimulation of the thyroid gland with bTSH in small doses leads to consistent increases of thyroid hormones, especially T3 and fT3, that the response varies between individuals, and that the precursor diiodotyrosine is released together with thyroid hormones.

Adult↗
PubMed1983

[Sonographic determination of thyroid volume in subjects with healthy thyroids].

Echography of the thyroid was performed on 542 persons with thyroid glands normal to palpation. Thyroid volume in men ranged between 9 and 38 ml, in females between 6 and 25 ml; median 16.7 ml and 13.5 ml, respectively. This sex difference is significant. There was only a weakly positive correlation between thyroid size, on one hand, and age or surface area, on the other. In future, thyroid echography should be used as reliable and yet simple method in any epidemiological study of the incidence of goitre.

Adolescent↗