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Biomedical subjects

G Benker

Publications and source records attributed to G Benker.

At least 37 records · Page 2Linked to original sources
PubMed1992

Treatment of juvenile goitre with levothyroxine, iodide or a combination of both: the value of ultrasound grey-scale analysis.

The effects of oral iodide, levothyroxine and of iodide and levothyroxine in combination were studied in three groups of 30 children, age 13-15 years, with euthyroid goitre. As endpoints of this study, we used thyroid volume reduction, thyroid hormones, thyrotropin and thyroid grey-scale histograms by computerized analysis. The three groups were well matched with respect to mean age, body weight and pretreatment thyroid volumes and thyroid hormones. Mean urinary iodide excretion before treatment was in the range of 30 micrograms/g creatinine, since the study was conducted in an iodine-deficient area. All three treatment regimens led to significant reductions in thyroid volume within one month. After six months on 100 micrograms of levothyroxine, thyroid volume had decreased from 14.1 +/- 4.2 ml to 8.3 +/- 2.6 ml (mean +/- SD); on 150 micrograms of iodide, from 18.5 +/- 6.2 ml to 8.8 +/- 2.7 ml; and on 100 micrograms of iodide plus 50 micrograms of levothyroxine, from 17.2 +/- 3.1 ml to 8.3 +/- 2.0 ml. When treatment was discontinued for three months, or the dosage reduced, thyroid volume increased again in the levothyroxine (to 11.3 +/- 2.5 ml) but not in the iodide group. Grey-scale values (by ultrasound, computer-aided estimation) after nine months were significantly different between the three treatment groups; no change was observed with levothyroxine, but after 150 micrograms of iodide as well as after combined treatment with levothyroxine and iodide there were marked decreases of grey-scale values; this is interpreted as reflecting a decrease in follicle size and colloid content of the thyroid which takes place after iodide supplementation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[The concentration of atrial natriuretic peptides (ANP). ANP in different sections of the circulation during atrial volume load with and without anesthesia].

We studied the effect of a volume load induced by a 45 degrees Trendelenburg position on atrial natriuretic peptide (ANP) secretion in awake and anaesthetized patients with coronary artery disease undergoing aortocoronary bypass surgery. ANP was measured in different parts of the circulation before and after induction of high dose fentanyl anaesthesia at fixed times prior to and after extracorporeal circulation. METHOD. In eight patients with coronary artery disease (NYHA classification II-III), who received neither diuretic nor positive inotropic therapy, ANP was measured in the various parts of the circulation: in a peripheral vein, a radial artery, in the pulmonary artery and in the coronary sinus. The measurements were made in the supine and 45 degrees Trendelenburg position. Measurements of mean arterial pressure (MAP), central venous pressure (RAP), pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI) and heart rate (HR) were taken simultaneously. The measurements were taken in the awake patient, during steady-state high-dose fentanyl anaesthesia with 50% O2 in N2O and after extracorporeal circulation. RESULTS. Compared to measurements in a control group, ANP levels were significantly higher in all parts of the circulation in patients with coronary artery disease, although clinical symptoms of heart failure were absent. After extracorporeal circulation, significantly higher levels of ANP were found at all measurement sites; however the concentration gradient of ANP between coronary sinus and arterial or venous blood was reduced. In awake and anaesthetized patients a change in body position, causing a significant increase in filling pressures, did not produce an increase in ANP levels at all measurement sites. The induction of high-dose fentanyl anaesthesia did not have an influence on plasmatic ANP levels. CONCLUSION. The results of this study lead to the following conclusions: 1. ANP levels in patients with CAD are increased, even if clinical heart failure symptoms are absent. 2. ANP is secreted in the coronary vessels. Following dilution in the atrial blood, it is metabolized to inactive compounds in the periphery. 3. Basic ANP levels are not changed by high-dose fentanyl anaesthesia. Marked increases of the filling pressures do not correlate with atrial ANP levels either before or after induction of anaesthesia. 4. After extracorporeal circulation ANP levels are significantly increased in all parts of the circulation. The concentration gradient between coronary sinus blood, on the one hand, and arterial and venous blood on the other hand is reduced. This phenomenon is probably caused by an alteration in the metabolism of ANP during hypothermic extracorporeal circulation.

Aged↗
PubMed1991

[Coincidence of non-medullary thyroid cancer and hyperparathyroidism].

Hyperparathyroidism (HPT) and non-medullary thyroid carcinoma are not related by a common embryologic origin. In a 5-years period (1985-1989) 163 patients were operated for HPT at our hospital. Of these, 54 patients had concurrent thyroid disease, which was operated simultaneously. In 6 cases, thyroid carcinoma was found, e.g. 3.7% of all patients. This prevalence compares well to reports of different authors in the literature. The most probable explanation is the early diagnosis of asymptomatic occult papillary carcinomas; this was true in 4 of our 6 patients with thyroid malignancy.

Adenoma↗
PubMed1990

Control of prolactin secretion.

1. Prolactin is a 21,500 Dalton single-chain polypeptide hormone but may occur in 50 kDa and 150 kDa molecular variants. 2. These large PRL variants may be secreted predominantly; this condition is termed "macroprolactinemia". It is characterized by high immunological and normal biological serum levels of prolactin, and lack of clinical symptoms of hyperprolactinemia. 3. The information on PRL is encoded on chromosome 6. Transcription can be enhanced and suppressed by a variety of hormonal factors. 4. PRL is secreted in a pulsatile fashion; it displays a circadian rhythm (with a maximum during sleep) and is stimulated by some amino acids. PRL also responds to mechanical stimulation of the breast. 5. PRL rises during pregnancy, and maintainance of hyperprolactinemia (and, thereby, physiological infertility) is dependent on the frequency and duration of breast feedings. 6. Hypothalamic regulation of prolactin mainly involves tonic inhibition via portal dopamine. The physiological importance of various stimulating factors present in the hypothalamus is still incompletely understood. In particular, there is still no place for TRH in PRL physiology. 7. PRL is released in response to stress; this response may be mediated by opioids. The low-estrogen, low-gonadotropin amenorrhea of endurance-training women is not mediated by prolactin, however. 8. Estrogens stimulate PRL gene transcription via at least two independent mechanisms. There are many clinical examples of this estrogen effect on prolactin serum levels, and also on the growth of prolactinomas. 9. Mild hyperprolactinemia remains an enigma which cannot satisfactorily be resolved by biochemical or radiological testing. The border between "normal" and "elevated" prolactin is ill-defined. The possibility of macroprolactinemia complicates this matter even further. 10. The number of drugs which suppress prolactin by acting on pituitary D2 receptors, and which are useful in the treatment of hyperprolactinemia, continues to increase. In the field of ergot alkaloids, parenteral application appears to be a logical solution to the problem of the high first-pass effect; in addition, this form of treatment is frequently better tolerated than the oral route. 11. Prolactinoma development is presently being studied employing molecular biological techniques; the question of whether tumorigenesis can be attributed to specific defects of gene regulation remains to be answered.

Adult↗
PubMed1990

Acromegaly and hypertension: prevalence and relationship to the renin-angiotensin-aldosterone system.

The prevalence of arterial hypertension was evaluated in a retrospective study of 158 patients with acromegaly, and results were compared to control populations, namely, the Munich Blood Pressure Study (MBPS) and the Framingham Study. The prevalence of hypertension (defined according to WHO criteria) was significantly increased in female patients but not in men; hypertensive acromegalics were older and tended to have higher body weight compared to normotensive patients. Hypertension was not related to serum concentrations of growth hormone. After successful treatment of acromegaly, growth hormone levels and systolic and diastolic blood pressure fell only in female hypertensive acromegalics; this did not occur in normotensives. The rise in plasma renin activity in response to upright posture was diminished in 57.9% of acromegalic patients. The prevalence of low-renin hypertension in our group of patients was 31.6%, which is similar to figures reported for unselected non-acromegalic subjects with essential hypertension. Orthostatic renin activity was weakly and inversely related (r = -0.3) to blood pressure. No relationship between plasma aldosterone concentration and blood pressure could be detected; however, in acromegalic women, aldosterone rose higher after ambulation than in men. In conclusion, hypertension is a common problem in acromegaly and at least in part related to similar risk factors in control populations. The association with abnormalities of the renin-angiotensin-aldosterone system is difficult to interpret and does not offer an explanation for the slight increase in the prevalence of hypertension.

Acromegaly↗
PubMed1990

[What is the recurrence rate for Basedow's disease treated with thyrostatic agents. Answers from a prospective study].

Graves' disease is an autoimmune disease whose development involves immunogenetic and exogenous factors such as viruses, bacteria and iodine excess. In a number of patients the disease follows a chronic recurrent course. A recurrence rate of 50% can be expected one year after the end of therapy. Based on the preliminary results of the prospective study presented here, this recurrence rate does not differ in groups where patients underwent long-term treatment with 10 or 40 mg thiamazole. Retrospectively obtained data suggest that the time at which euthyroidism occurs under low-dose treatment is dependent on the alimentary iodine supply. A number of groups have attempted to develop clinically applicable methods to identify patients at risk for recurrence at the end of treatment. All the studies yielded controversial results. A prospective multicenter study was undertaken to reinvestigate the importance of measuring TSH receptor antibodies and performing the TRH test and the suppression test at the end of therapy in connection with this problem. In 451 patients the recurrence rate was 50.3% one year after the end of treatment. The patients in the recurrence group had a significantly higher rate of persistent antibody activity, no increase in TSH after TRH (negative TRH test), no normal suppressibility of thyroid 123 iodine uptake (negative suppression test) and larger goiter. The calculation of sensitivities and specificities shows, however, that these differences are not large enough to be of clinical importance for the individual patient.

Autoantibodies↗
PubMed1990

Survival rates in patients with differentiated thyroid carcinoma. Influence of postoperative external radiotherapy.

Nine hundred thirty-two patients with papillary and follicular thyroid carcinomas were seen at the Departments of Medicine, Surgery, and Radiology of the University of Essen, Essen, Germany, between 1970 and 1986. In addition to standard treatment by surgery, radioactive iodine and medical thyroid stimulating hormone (TSH) suppression, 346 patients had received conventional external irradiation to the neck (mostly 40-60 Gy) before referral to our institutions, whereas 586 patients had not received radiotherapy. From the follow-up data of these patients, survival rates were calculated separately for tumor Stages T1 (n = 203), T2 (n = 552), and T3/T4 (n = 277) using life-table analysis. Distribution of risk factors (histologic type of tumor, grading of malignancy, presence of distant metastases, age and sex) was similar in all groups with the one exception, that the radiotherapy patients with Stage T3/T4 were older. There was no significant difference in the life expectancy of irradiated and not irradiated patients by Breslow and Mantel-Cox tests. In Stages T1, T2, and T3/T4, 75% of the radiotherapy patients survived for 10.6 +/- 0.32, 11.5 +/- 0.61, and 6.71 +/- 0.85 years, respectively; the figures for the nonirradiated patients were 9.4 +/- 0.17, 10.8 +/- 0.37, and 6.26 +/- 0.51 years, respectively. When survival rates were calculated separately for patients with Stage T3/T4 older and younger than 40 years, there was no obvious effect of radiotherapy in the younger group, whereas in the older patients, improvement of survival by radiation just failed to reach statistical significance (P less than 0.09). In conclusion, this retrospective analysis failed to prove that survival is prolonged in patients with differentiated carcinoma by administration of conventional external radiotherapy after surgery. A benefit to older patients with locally advanced tumors has still to be demonstrated.

Adenocarcinoma↗
PubMed1990

[A registry of medullary thyroid cancer in West Germany].

A register for medullary thyroid carcinoma (MTC) in FRG has been set up by the "German Medullary Thyroid Carcinoma Study Group" in 1988. The aim is to provide a basis for collaborative work on MTC especially in the hereditary forms (i.e. multiple endocrine neoplasia [MEN] type IIa, IIb). For these hereditary varieties reliable screening tests exist and, if the disease is detected by family screening in an early stage, curative surgery is possible. Until now 408 patients (234 female, 174 male) with MTC have been reported by 17 cooperative centers. The mean age at diagnosis was 45.5 years. 25% (n = 104) are hereditary forms, most of them MEN IIa (n = 86), 13 are MEN IIb and 18 belong to the familial variety without other endocrinopathy. The mean age at diagnosis for MEN IIa was 36.5 years, MEN IIb 26.9 and for the pure familial form 27.5 years. As 33 patients per year have been diagnosed since 1982, nearly 25% of all expected cases of MTC in FRG have been registered.

Adult↗
PubMed1990

TSH secretion in Cushing's syndrome: relation to glucocorticoid excess, diabetes, goitre, and the 'sick euthyroid syndrome'.

Thyrotrophin (TSH) secretion was studied in 63 patients with Cushing's syndrome (53 patients with pituitary dependent Cushing's disease, eight with adrenocortical tumours, and two with the ectopic ACTH syndrome). Prior to treatment, TSH response to 200 micrograms of TRH intravenously was significantly decreased compared to controls; TSH response was 'flat' (increment less than 2 mU/l) in 34 patients (54%). Patients with a flat response to TRH had significantly higher morning and midnight cortisol levels than patients with a TSH response of 2 mU/l and more; this was not due to differences in serum thyroid hormone levels. Basal TSH, TSH increment after TRH, and stimulated TSH value, but not serum triiodothyronine, were correlated with cortisol measurements (0800 h serum cortisol, midnight cortisol, and urinary free corticoid excretion). After exclusion of 40 patients with additional disease (severe systemic disease, diabetes mellitus, or goitre), cortisol-TSH correlations were even more pronounced (r = -0.73 for midnight cortisol and stimulated TSH levels), while in the patients with additional complications, these correlations were slight or absent. Successful treatment in 20 patients was associated with a rise in thyroid hormone levels and the TSH response to TRH. These results indicate that (1) the corticoid excess but not serum T3 is the principal factor regulating TSH secretion in Cushing's syndrome, (2) a totally flat response to TRH is rare, and (3) TSH suppression and lower than normal serum thyroid hormone levels are reversible after treatment. Since factors like severe systemic disease, diabetes mellitus and goitre also affect TSH secretion, they tend to obscure the statistically significant correlations between cortisol excess and TSH secretion.

Adult↗
PubMed1990

Infusion of low dose etomidate: correction of hypercortisolemia in patients with Cushing's syndrome and dose-response relationship in normal subjects.

To investigate the adrenostatic potential of a nonhypnotic low dose etomidate infusion, we administered 0.03 mg/kg etomidate in a bolus injection, followed by constant infusion of 0.3 mg/kg.h for 24 h to 6 patients with severe Cushing's syndrome. The dose-response relationship also was determined in 15 normal subjects. Three groups of 5 received, respectively, doses of 0.03, 0.1, and 0.3 mg/kg.h etomidate for 5 h after an initial bolus dose of 0.03 mg/kg. The response to exogenously administered ACTH [0.25 mg ACTH-(1-24)], injected after the etomidate or control infusion, was determined in all normal subjects. In the six hypercortisolemic patients, serum cortisol concentrations decreased from 1374 +/- 436 nmol/L (mean +/- SEM) to 188 +/- 91 nmol/L after 11 h of etomidate infusion and remained low until the end of the infusion. Cortisol levels returned to pretreatment concentrations by 24 h. Excretion of urinary free cortisol decreased from 1180 +/- 196 to 185 +/- 66 nmol/day. In the normal subjects, administration of etomidate led to a dose-dependent decrease in serum cortisol from about 550 to 83 nmol/L, while 11-deoxycortisol rose from low or undetectable levels up to 346 nmol/L. In response to ACTH, cortisol levels rose in inverse proportion to the etomidate dose. It was, however, significantly reduced compared to normal saline infusion even after the lowest dose. Changes in aldosterone and corticosterone concentrations were similar to those in cortisol, and 11-deoxycorticosterone changed in a pattern similar to that of 11-deoxycortisol. Two of five normal subjects reported tiredness during the highest etomidate infusion. No other side-effects were noted. We conclude that iv administered etomidate in a low nonhypnotic dose reduces serum cortisol concentrations in a dose-dependent manner in both hyper- and eucortisolemic subjects. This study suggests that etomidate at a dose of 0.1 mg/kg.h or lower may be an effective strategy for the control of severe hypercortisolemia.

Adolescent↗
PubMed1990

A multihormonal response to corticotropin-releasing hormone in inferior petrosal sinus blood of patients with Cushing's disease.

Bilateral, selective, and simultaneous catheterization of the inferior petrosal sinus is not only a valuable tool in the differential diagnosis of Cushing's syndrome, but may also provide new insights into paracrine interactions at the pituitary level. We have investigated whether CRH (1 microgram/kg BW) has any effect on the release of PRL, GH, TSH, or the alpha-subunit of hCG during this procedure. Sixteen patients under evaluation for Cushing's syndrome (Cushing's disease, n = 12; ectopic ACTH syndrome, n = 2; glucocorticoid resistance, n = 1; hormonally inactive adenoma, n = 1) were catheterized. Two of the patients with Cushing's disease received 4.0 mg naloxone iv 15 min before stimulation with CRH. Patients with Cushing's disease demonstrated a central/peripheral gradient and an intersinus gradient not only for ACTH, but also for PRL, alpha-subunit, GH, and TSH, provided that the latter two hormones were not completely suppressed by the glucocorticoid excess. Moreover, all hormones increased in response to CRH on the side with the highest ACTH concentration; PRL rose from 31.2 +/- 6.4 to 61.6 +/- 12.4 micrograms/L (P less than 0.01), and alpha-subunit from 2.6 +/- 0.6 to 6.4 +/- 1.7 micrograms/L, (P less than 0.01). Naloxone was unable to abolish the PRL or alpha-subunit increase in response to CRH. A multihormonal response to CRH in inferior petrosal sinus blood was also observed in the patient with glucocorticoid resistance and in the patient with the hormonally inactive tumor, but not in the patients with ectopic ACTH secretion. The multihormonal response to CRH could be explained by cosecretion of other hormones together with ACTH from corticotroph adenoma, by an effect of CRH on pituitary blood flow, or by a paracrine action of pituitary corticotrophs on adjacent normal pituitary cells. Our results do not support the concept that such a paracrine action is mediated by beta-endorphin. However, a higher dose of naloxone may be required to antagonize the action of pituitary beta-endorphin.

Adrenocorticotropic Hormone↗
PubMed1990

Antithyroid drug treatment of Graves' disease in pregnancy: long-term effects on somatic growth, intellectual development and thyroid function of the offspring.

With regard to their thyroid function, somatic and intellectual development, we compared 17 children of 13 hyperthyroid mothers (group I) receiving antithyroid drug treatment during their pregnancies with 25 children of 15 mothers who were euthyroid without any antithyroid treatment during their pregnancy (group II). Mean duration of maternal treatment was 3.5 months in group I, using carbimazole or thiamazole (N = 12) and propylthiouracil (N = 1). Age at examination in group I was 7.2 +/- 6.2 years, in group II 8.7 +/- 7.1 years (mean +/- SD). Both groups showed no significant differences in the results of the clinical examination and in the degree of their mental and psychomotoric development at the time of study. We found the mean birth weight of the infants in group I significantly lower than in group II (3165 +/- 339 vs 3666 +/- 670 g, p less than 0.03). The individual birth weights, however, were normal for gestational age. The body weight difference between groups disappeared during the further somatic development of the children. The serum concentration of free thyroxine in group I was significantly higher than in group II (17.2 +/- 2.4 vs 14.9 +/- 1.9 pmol/l, p less than 0.003), but fell in both groups within the normal range. The evaluation of the psychomotoric and intellectual capacity of the children at different developmental stages showed no abnormalities detectable by our tests. Thus, in the children of the two groups we found no adverse effects of a maternal antithyroid drug treatment during pregnancy or of inactive maternal Graves' disease alone, neither on thyroid gland size and function nor on the physical or intellectual development, after the neonatal period.

Birth Weight↗
PubMed1990

New therapeutic approaches in thyroidal autoimmune diseases.

Antithyroid drugs (AD) still represent the most widely chosen therapy for hyperthyroidism of Graves' disease. Since their interaction with iodine is still poorly understood, this was addressed in multicenter clinical trials. The interaction of iodine and methimazole was studied in 260 patients from iodine deficient countries. Whereas patients with very low iodine supply needed low doses of methimazole, patients with even slightly increased iodine supply needed high doses of methimazole to remain euthyroid. In another study of 1256 patients side effects of AD were shown to be dose-dependent. Immunological markers of thyroid autoimmunity disappear in most patients during treatment with AD although with many exceptions. Remissions after treatment with AD may represent disease heterogeneity within a spontaneous disease course and the spectrum of relapsing hyperthyroidism over euthyroidism to hypothyroidism. Lastly therapeutic strategies in thyroid eye disease have not provided evidence which therapy is superior.

Antithyroid Agents↗
PubMed1990

[Subtotal thyroid gland resection in immunogenic hyperthyroidism: results of a 9-year period].

UNLABELLED: From 01. 01. 1980-31. 12. 1988 149 patients with Graves' disease were subtotally thyreoidectomized with little rests of 2-3 g on each side. The nervi recurrente and the parathyreoids were exposed. RESULTS: There was only one permanent pulsy of the recurrence nerve and no permanent hypoparathyreoidsm. 146 patients could be observed: two had a recidiv and must be treated with radiojodine. 70% of our patients were hypothyreotic, 20% euthyreotic. We think that the operation is the therapy of choice in young patients with Graves' disease.

Adolescent↗
PubMed1990

[Coincidence of hyperparathyroidism and thyroid gland cancer].

127 patients, operated for hyperparathyroidism in a 4-years period (1986-1989) were analyzed retrospectively, regarding concurrent thyroid disease. In 42 patients (33%) thyroid resection was performed simultaneously. Of these, in five cases (4%), thyroid malignancy was discovered: there was one follicular carcinoma, one multilocular papillary tumor and three well differentiated small papillary carcinomas (less than 1.5 cm diameter). This prevalence of thyroid tumors is comparable to the results of different authors (2.5-8.5% in the literature). We conclude that preoperative examination should include the thyroid gland before parathyreotoid exploration.

Adenoma↗