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Biomedical subjects

B Niederle

Publications and source records attributed to B Niederle.

At least 127 records · Page 7Linked to original sources
PubMed1990

Evaluation of glucose tolerance, insulin secretion, and insulin action in patients with primary hyperparathyroidism before and after surgery.

Glucose tolerance, insulin secretion, and insulin sensitivity were evaluated in 8 asymptomatic patients with primary hyperparathyroidism (PHPT) before and at least 8 weeks after surgical correction of PHPT by means of the hyperglycemic clamp technique. In addition, 15 sex- and age-matched control subjects were investigated for comparative reasons by the same technique. Glucose metabolized (M) during the hyperglycemic clamp was not significantly (NS) different between patients with PHPT and controls (7.9 +/- 2.3 vs. 6.3 +/- 1.9 mg/kg/min). However, insulin secretion (I) was significantly elevated in patients with PHPT compared to controls (87 +/- 17 vs. 45 +/- 12 microU/ml, P less than 0.05). The calculated insulin sensitivity index (M/I) was significantly reduced in PHPT compared to controls (11.0 +/- 2.1 vs. 15.2 +/- 1.4 mg/kg/min per microU/ml x 100, P less than 0.05). Comparing patients with PHPT before and after surgery, the M value, which is a measure of glucose tolerance, was not significantly different (7.9 +/- 2.3 vs. 7.8 +/- 1.5 mg/kg/min). However, insulin secretion was significantly lower after surgical correction of PHPT compared to the preoperative situation (48 +/- 9 microU/ml vs. 87 +/- 17 microU/7 ml, P less than 0.01). The calculated M/I rose significantly after surgery compared to the preoperative value (11 +/- 2.1 vs. 17.6 +/- 2.7 mg/kg/min per microU/ml x 100, P less than 0.001). We conclude that disturbed carbohydrate metabolism, such as insulin hypersecretion and insulin resistance, in patients with PHPT is an early finding in this disease and that these early disturbances in glucose metabolism are, however, fully reversible.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Endoscopic tube implantation for the palliation of malignant esophageal stenosis.

One hundred endoscopic tube implantations were carried out on 95 patients with malignant esophageal stenosis. Palliative treatment was performed in 43% of cases because of the advanced stage of the tumor, and in 57% of cases because of risk factors which made resection inadvisable. Clinical mortality was 16%, with six deaths caused by technical complications (perforation, arrosion bleeding), and ten by cardiopulmonary problems. Dislodgement or obstruction of the prostheses was observed in 20% of cases, but could readily be corrected. The median survival time was two months, with 17% of the patients still alive after six months. Poor general health, advanced age and the presence of distant metastases were established as unfavorable prognostic indications with a significant influence on postoperative mortality. Functional results were good: 87% of patients were able to eat solid or pulpy food post-operatively.

Adult↗
PubMed1990

Cardiac calcific deposits in patients with primary hyperparathyroidism: preliminary results of a prospective echocardiographic study.

To explain the incidence and significance of mitral and aortic valve calcification and calcific deposits in the myocardium, a prospective echocardiographic study was performed with 21 consecutive patients who had primary hyperparathyroidism (PHP) and with 21 age- and sex-matched control subjects with normocalcemia. Calcific deposits in the myocardium were seen in 13 patients (62%) with PHP, mainly in the interventicular septum, and in one control subject. Aortic valve calcification was observed in 12 patients (57%) with PHP and in one control subject. Calcification of the mitral valve was found in seven patients with PHP (33%) and three controls (14%). Calcification led to mild or moderate stenosis of the aortic valve in three patients with PHP and of the mitral valve in two patients with PHP. No stenosis was found in the subjects in the control group. Both calcification of the aortic and mitral valves and calcific deposits in the myocardium are common in patients with PHP and can be detected noninvasively by echocardiography. Because of the potential relationship of elevated calcium, calcification, and valvular heart disease, clinical evaluation of PHP should include echocardiographic studies before surgery is performed and during follow-up examination.

Adult↗
PubMed1990

Intraatrial extension of thyroid cancer: technique and results of a radical surgical approach.

An occlusion of the superior vena cava by a tumor thrombus extending into the right atrium was diagnosed in three patients with a follicular thyroid cancer. All patients showed the typical clinical picture of the superior vena cava syndrome. A right parasternal thoracotomy was performed for preparation of the major vessels. The superior vena cava was opened and the entire intravascular tumor thrombus was removed. The cavotomy was closed directly in two patients. In the third patient the left brachiocephalic trunk was resected and reconstructed with a vascular (polytetrafluoroethylene) graft. This patient had bone and brain metastases and an occlusion of the graft 3 months after surgery after anticoagulation was stopped. The other two patients were clinically symptom free without local recurrence 13 and 50 months after surgery. An aggressive surgical approach is justified in grossly invasive thyroid cancer to decrease local recurrence and death rates, to correct the disturbing clinical symptoms of superior vena caval occlusion, and to prevent tumor embolism and the development of distant metastases. By reducing tumor mass, an even better basis for radioiodine treatment can be prepared.

Adenocarcinoma↗
PubMed1989

Groin infections following vascular surgery: obturator bypass (BYP) versus "biologic coverage" (TRP)--a comparative analysis.

Deep infections in the groin complicating vascular surgical procedures pose a serious problem, in the treatment of which two alternative methods are available: (1) Removal of the graft and the construction of an extra anatomic bypass (obturator canal bypass, BYP), or (2) retaining the graft and achieving healing of the infected wound by various biological materials, such as omentum or an inferior rectus abdominis muscle flap (TRP). The probability of patient and limb survival was estimated by the Kaplan-Meier method and possible differences between both groups checked using Breslow's and Mantel's tests. No statistically significant differences were found and a variety of factors with potential influence on the outcome were considered equally balanced. However, as soon as the catastrophic event of infection plus haemorrhage enforced emergency surgery, the incidence of success differed markedly: in the BYP group 6 infections healed out of 8 and in the TRP group 1 out of 6.

Adult↗
PubMed1989

Dislocated Atkinson tubes: removal and repositioning with a balloon catheter.

Atkinson tubes are inserted endoscopically for palliation of obstructing esophageal carcinoma. A technique was developed to reposition or remove dislocated tubes that involves the use of a dilation balloon catheter. The technique was successful in treating three partially dislocated tubes and one of two completely dislocated tubes (tubes completely dislodged into the stomach). The only complication occurred in two patients who coughed up a small amount of blood.

Aged↗
PubMed1989

Transforming growth factor beta regulates thyroid growth. Role in the pathogenesis of nontoxic goiter.

The production and growth regulatory activity of transforming growth factor beta were studied in human thyroid tissue. As estimated by its mRNA expression in fresh tissue samples, transforming growth factor beta was produced in normal and in diseased thyroid glands. Transforming growth factor beta mRNA was mainly produced by thyroid follicular cells and in lesser quantities by thyroid infiltrating mononuclear cells. The concentrations of transforming growth factor beta mRNA were lower in iodine-deficient nontoxic goiter than in Graves' disease and normal thyroid tissue. Transforming growth factor beta protein secretion by cultured thyroid follicular cells was also low in nontoxic goiter, but could be increased by addition of sodium iodide (10 microM) to the culture medium. Recombinant transforming growth factor beta did not affect basal tritiated thymidine incorporation in cultured thyroid follicular cells, but inhibited, at a concentration of 10 ng/ml, the growth stimulatory influence of insulin-like growth factor I, epidermal growth factor, transforming growth factor alpha, TSH, and partly that of normal human serum on cultured thyroid follicular cells. This inhibition was greater in Graves' disease than in nontoxic goiter. These results suggest that transforming growth factor beta may act as an autocrine growth inhibitor on thyroid follicular cells. Decreased transforming growth factor beta production and decreased responsiveness to transforming growth factor beta may be cofactors in the pathogenesis of iodine-deficient nontoxic goiter.

Adult↗
PubMed1989

[Parathyroidectomy and autotransplantation in renal hyperparathyroidism. II. Morphologic and functional studies in transplant-dependent recurrence].

Corresponding to predefined macroscopic criteria indicating morphological and functional characteristics, fragments of a type 1a-gland were used after total parathyroidectomy for auto-transplantation in 16 hemodialyzed patients with drug-resistant renal hyperparathyroidism (rHPT). Fragments of a type 1b-gland were used in two, fragments of a type 2-gland in 17 patients, respectively. The clinical and biochemical follow-up three to 84 months postoperatively showed one patient (3%) with graft-dependent hypocalcemia (type 1a-graft) and in two patients (6%) with type 2-grafts histological examinations confirmed graft-dependent recurrent hyperparathyroidism. Thus the estimated cumulative success (= normal parathyroid metabolism; Kaplan Meier) was 78 +/- 12% 5 years postoperatively. Comparing the estimated cumulative function rate of type 1a- and type 2-autotransplants, a better course was found in typ 1a-grafts three years postoperatively (Breslow: p = 0.0724; Mantel-Cox: p = 0.0677). The morphological examinations of the removed enlarged fragments of different size (between 0.2 cm and 0.9 cm) showed signs of an expansive, but never invasive growth. The chief and oxyphilic cells were intermixed and arranged in a follicular pattern as in the former glands selected for grafting. Mitoses could be found more often in larger fragments, thus correlating with a tendency to proliferation and a bad in vitro suppressibility. The results of the studies confirm the conclusions of an in vitro study, showing that the diffuse hyperplastic type 1a-parathyroids are most suited for autotransplantation. Glands or gland areas without fat-cells (type 1b) or nodules of type 2-glands which can be identified intraoperatively using a stereomagnifier should not be used.

Adult↗
PubMed1989

Morphologic and functional studies to prevent graft-dependent recurrence in renal osteodystrophy.

The cross sections of hyperplastic glands removed during total parathyroidectomy in patients with renal osteodystrophy were classified on the basis of macroscopic and functional criteria. Diffuse (type 1) and nodular (type 2) glands could be distinguished macroscopically. Functional in vitro studies showed no significant difference in suppressibility and basal parathyroid hormone (PTH) secretion (61% and 74%, respectively). In both types of glands A, B, C, and D regions could be distinguished with use of a stereo magnifier (magnification, x10 to x16). In diffuse A regions containing stroma fat cells, PTH secretion could be suppressed optimally (more than 50% of maximum secretion) in more than 90% of all specimens in vitro. In diffuse B regions containing no fat cells, hormonal secretion could be suppressed in only 17% and 25%, respectively. Confined (oxyphilic or chief cell) nodules (C regions), only found in type 2 glands, could be suppressed in 18%. Nodules of "degenerating" oxyphilic cells (D regions), only found in type 2 glands, were suppressible, but the low PTH secretion indicated degenerative processes. Thus only fragments from A regions should be selected for autotransplantation.

Calcium↗
PubMed1989

[The covering of the infected cubital vessels after complications of dialysis shunts by the use of the musculus brachioradialis].

The case of a 52-year-old patient with uremia and infection in his av-shunt (homologous saphenous vein) is described. Due to the infection a rupture of the venous anastomosis in the cubital area with acute hemorrhage occurred and the av-fistula had to be removed and the artery repaired by an autologous vein patch. To cover the exposed cubital artery and the infected ventral elbow area a brachioradial muscle flap was inserted. By this procedure the amputation of the upper extremity could be avoided. Full range of extension and flexion was obtained within 4 weeks.

Anastomosis, Surgical↗
PubMed1988

[Magnetic resonance tomography as a localization method in hyperparathyroidism].

Magnetic Resonance Imaging (MRT) was performed in 36 consecutive patients with hyperparathyroidism. MR tomograms of 31 patients were evaluated and compared with the results of operation and histology (n = 29). In the remaining 5 patients MR examination was not completed, due to claustrophobia or motion artefacts. MR examinations were performed in 2 superconductive magnets (0.5 and 1.5 Tesla). A surface coil with following spinecho sequences was used: SE: TR/TE: 550-700/15-30; 2000/22-100. All patients were subjected to additional sonography. Out of 28 parathyroid adenomas 25 were identified on MR tomograms (sensitivity: 73%, specificity: 90%). However, only 2 out of 6 hyperplastic parathyroid glands were localized on MR tomograms. Lesions missed on MR tomograms measured 15 mm and less in diameter. It is characteristic that parathyroid adenomas showed isointense MR signal to the thyroid (SE 550/30 and hyperintense MR signal to fat (SE 2000/100). Different signal intensities of the adenomas were observed in 25% of the cases. MR imaging is a valuable diagnostic method for preoperative localisation of parathyroid adenomas. We think that MR imaging should be performed when sonography and subtraction scintigraphy are not able to identify a suspected adenoma in the same location.

Adenoma↗
PubMed1988

[Recurrent renal hyperparathyroidism: reoperation on the autograft].

Graft-dependent recurrence was observed 24 and 27 months after total parathyroidectomy and immediate autotransplantation in 2 out of 35 haemodialized patients (6%) with reactive (renal) hyperparathyroidism. In order to normalize the altered parathyroid metabolism in these 2 patients 7 reductions of the graft have been required so far in the patients and cervico-mediastinal reexploration was necessary as an additional procedure in one of the patients. Histological examination of the more or less enlarged fragments showed nearly the same architecture as the original glands used for grafting. Proliferating chief cell nodules with mitoses and signs of expansive, but never invasive growth were seen. Reviewing the literature, 38 authors describe 61 graft-dependent recurrences in 783 patients (7.8%) since 1975. Our own experiences and those in literature are discussed with respect to diagnosis, differential diagnosis, localization and histology of the graft-dependent recurrence.

Follow-Up Studies↗
PubMed1988

[Epidemiological research on primary hyperparathyroidism. A prospective multicenter study].

Serum calcium determination of 11,588 hospitalized patients during a twelve-month period revealed hypercalcaemia in 74 (0.64%). Further clinical and biochemical investigation established primary hyperparathyroidism in 20 of them (27%), and in 15 (20%) a malignant tumour (with bone metastases in six) as the cause of the hypercalcaemia. Rarer causes were found in 11 patients (15%): diuretic medication (5), lithium treatment (3), immobilization (2) or hyperthyroidism (1). In the remaining 28 patients (38%) no cause of the hypercalcaemia could be established with certainty. In at least six patients, however, there were clinical pointers towards hyperparathyroidism in the absence of unequivocal biochemical findings. Leaving out of account borderline cases, one must reckon on a prevalence of hyperparathyroidism in 0.17% of an unselected group of hospitalized patients. Parathyroid hyperfunction must always be considered in the differential diagnosis because of its manifold clinical presentation.

Austria↗
PubMed1988

[Parathyroidectomy and autotransplantation in renal hyperparathyroidism. I. Morphologic studies for tissue selection].

During total parathyroidectomy and autotransplantation 140 enlarged glands were removed in 35 hemodialyzed patients (normocalcemic: n = 14; hypercalcemic: n = 21). The cross-sections of all glands were classified intraoperatively. Diffuse hyperplastic (type 1) and nodular hyperplastic (type 2) glands could be distinguished. Using a stereo-magnifier (magnification: x 10 -x 16), type 1a- (stromal fat cells!) and type 1b- glands (without stromal fat cells!) could be differentiated. Those areas were also found between the nodules of type 2-glands. Significantly, nodular hyperplastic glands predominated in hypercalcemic patients (chi 2-Test: p less than 0.001). The colour of the nodules on the cross-sections of type 2-glands correlated with the predominating cell type ("dark": nodule of oxyphile cells; "medium": nodule of chief cells; "light": nodule of 'degenerating' oxyphile cells). As sign of proliferation the mitotic index was elevated (greater than 1:10,000) in type 1b-glands, in type 1b-like areas and in nodules of type 2-glands. These areas should not be used for autotransplantation.

Adipose Tissue↗
PubMed1988

[Parathyroidectomy and autotransplantation in renal hyperparathyroidism. II. Functional in vitro studies for tissue selection].

The PTH secretion was studied in fragments of 83 (reactive) hyperplastic parathyroids (type 1 a: n = 24; type 1 b: n = 20, type 2: n = 39) simulating hypo- (0.3 mmol Ca++ = maximal PTH secretion), normo- (0.9 and 1.2 mmol Ca++) and hypercalcemia (3.0 mmol Ca++ = basic PTH secretion, maximal suppressibility) in vitro. 56 out of 83 glands (67%) were suppressible (PTH secretion decreased under 50% of maximal secretion) with no significant difference in suppressibility of diffuse and nodular hyperplasia (50% and 74%, respectively). Differentiating diffuse hyperplastic glands in those with (type 1 a) and without (type 1 b) stroma fat cells, 92% of type 1 a glands and only 25% of type 1 b glands were suppressible (Fischer's test: p less than 0.001). Separated (oxyphilic and/or chief cell) nodules, type 1 b- and type 1 a-like areas (both localized between nodules) of types 2 glands were suppressible in 18%, 17% and 91%, respectively (Fischer's test: p less than 0.001). Thus fragments of type 1 a regions should be autotransplanted for preference. Type 1 b regions or nodules should not be used for grafting.

Calcium↗