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Biomedical subjects

R Roka

Publications and source records attributed to R Roka.

At least 19 recordsLinked to original sources
PubMed1992

Radiation of jejunal interposition in T3-T4 upper aerodigestive tumours.

30 patients with T3 and T4 tumours of the upper aerodigestive tract had their tumours resected by pharyngolaryngectomy. This was followed by reconstruction of a gullet or creation of a siphon as a tracheohypopharyngeal shunt for voice restoration with a free jejunal autograft. All patients were treated postoperatively with 60Co gamma radiation, 6 MeV photons or 7.5 to 10 MeV electrons of a beta-tron, with a dose of 50-65 Gy in the area of the primary tumour and 50-65 Gy to the neck. 4 patients refused further treatment after a depth dose of between 16 and 32 Gy. Local recurrence occurred in 40% of cases. The survival rate was 36.6% (11/30) after a mean follow-up time of 21.5 months, although 2 patients died of intercurrent diseases without recurrence of their tumours. The results obtained justify active surgical intervention with postoperative irradiation even at an advanced stage of the tumour.

Aged↗
PubMed1992

Autotransplanted jejunum in patients with carcinomas of the head and neck: transport of immunosurveillance against tumor cells?

Autologous jejunum, transplanted as a functional replacement immediately after radical dissection of advanced stages of squamous cell carcinomas of the head and neck and subsequently irradiated, was examined by immunohistochemistry (APAAP/PAP-technique). Biopsies from 9 patients were taken at the time of transplantation and up to 24 months thereafter (group 1) and from 5 patients only once after transplantation (group 2). Twenty-six monoclonal antibodies (mAbs) were used as surface markers to give an overview about phenotypical changes with respect to T-, B- and M phi-antigens. 1) B cells: a general increase of CR2+ (CD21, p less than 0.01) could be noticed after transplantation, immunoglobulin positive cells remained unchanged expect for a significant decrease of IgM+ (p less than 0.01) and IgA1+ (p less than 0.01) cells. 2) The number of T cells (CD3+) showed no significant differences although TcR gamma/delta+ cells decreased (p less than 0.01) in the autotransplant. ICAM-1 (CD54) and IL-2R (CD25) were found on a significant (p less than 0.01) higher number of cells after transplantation. 3) Cells with M/M phi morphology showed increased expression of the Fc gamma receptors (CD64, p less than 0.001; CD32, n.s.; CD16, p less than 0.001), of the complement receptors CR1 (CD35, (p less than 0.001) and CR3 (CD11b, p less than 0.02), of HLA-DQ (p less than 0.01), and of the antigens 25F9 (mature M phi; p less than 0.01) and CD4 (p less than 0.02). Correlation analyses of data obtained from the biopsies of the 14 autotransplanted jejunum cases revealed a CD35+ and a 25F9+ subpopulation of M/M phi. Our findings indicate that despite irradiation autotransplanted jejunum contained cells with immunological capacities. Therefore, the replacement of larynx by autologous jejunum may facilitate not only mechanical but also immunological functions.

Adult↗
PubMed1992

Biologic and cytogenetic characterization of three human medullary thyroid carcinomas in culture.

Neuroendocrine features and cytogenetic abnormalities of one continuous cell line (MTC-SK) and two long-term cultures (GER, STAH) derived from three sporadic cases of human medullary thyroid carcinomas (MTCs) were studied. Specific neuroendocrine markers (NSE, chromogranins, calcitonin, calcitonin gene-related peptide) were identified by electron microscopy and immunocytochemistry. In situ hybridochemistry and Northern blot analysis confirmed endocrine activity. Cytogenetic studies of the cell line MTC-SK revealed three consistent marker chromosomes, t(3;10), 11p+, and 22p+. Cells of long-term cultures GER and STAH exhibited a consistent translocation t(2;18), a trisomy 7, and two consistent marker chromosomes der3 and 5p+, respectively. Recently, we have isolated 12 stable clones of this MTC-SK cell line, which showed two different growth patterns. Quantitative measurement of mitotic activity flow cytometry and semiquantitative analysis of AgNOR-, Ki67-, and Cyclin/PCNA-(immuno)reactivity showed different DNA composition and duplication rates, indicating at least two subpopulations. Some of our clones developed a new consistent marker (i.e., an unbalanced translocation between mar11p+ and 1q). However, no correlations between chromosome findings, growth rate, and neuroendocrine markers were observed.

Carcinoma↗
PubMed1992

[Multivisceral and extended resection in tumor surgery--esophageal cancer].

Extended resections are strategies in the surgical treatment of cancer which provide large oncological safety margins: these are of particular relevance in the neck in view of the close anatomical relation of the major cervical organs. In the region of the distal esophagus, extended resections may be a reasonable alternative to conservative approaches even when only intended as a palliative treatment. The removal of metastases does not influence the outcome in patients with esophageal carcinoma, in contrast to simultaneous surgery of other malignancies.

Esophageal Neoplasms↗
PubMed1991

[Histologic study of the effect of postoperative irradiation on free transplanted jejunal segments].

After the reconstruction of defects resulting from the resection of advanced tumors from the upper aerodigestive tract using free microvascular anastomized jejunum, the autotransplant is influenced by local radiotherapy (cumulative dose 50-70 Gray). Biopsies were taken from 15 patients, stained with haemotoxilin-eosin and Giemsa and compared by means of light microscopy with jejunum taken at the time of transplantation. It was possible to observe a widened mucosal and submucosal space two to three months after radiotherapy, similar to the clinical impression of a radiogenic enteritis. The villi were flat and shortened with no or slight epithelial lesions. Additionally, it was possible to observe an inflammatory infiltration consisting mainly of neutrophilic granulocytes, edemas, and telangiectases. The latter were also evident in nonirradiated autotransplanted jejunum and are therefore not only caused by irradiation. One year after radiotherapy the mucosal membrane was atrophic. Fibrosis was to be seen in the lamina propria, accompanied by widened muscularis mucosae. The submucosal space was also widened and fibrotic to a varying degree. It was possible to detect varying stages of alteration in the vascular system up to a complete obliteration. After two years, changes were more pronounced. At no time could any alteration in the nervous system of the plexus submucosus be observed. All of these changes have to be interpreted as a consequence of irradiation. However, lubrication of the mucosal surface and the motility of the transplant are not altered severely by irradiation and therefore the desired functions of the free transplanted jejunal grafts, such as swallowing and phonation, are carried out sufficiently.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
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

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

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↗
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↗