Biomedical subjects

Ctibor Povýsil

Publications and source records attributed to Ctibor Povýsil.

10 recordsLinked to original sources

PubMed2006

Reconstruction of the anterior cruciate ligament: dynamic strain evaluation of the graft.

The study is focused on the biomechanical aspects of the anterior cruciate ligament (ACL) reconstruction procedures with an emphasis on evaluating the dynamic strain of materials commonly used for this purpose. Separate and multiple, equally tensioned strands of hamstring grafts used for the reconstruction of the ACL were biomechanically tested and compared to original ACL and bone-patellar tendon-bone (BPTB) grafts, using tissue samples from cadavers. The study was focused on measuring such material properties as the strength, stiffness, maximum load, and elongation at maximum load of the original ACL, BPTB graft, and single tendon hamstring (gracilis and semitendinosus) grafts, continued by double strands and finally by four-strand graft (STG) evaluation. Fresh-frozen cadaveric knees were used, which had been clamped and tensioned equally. The measurement was performed by drop-weight testing, using a Laser Doppler Vibrometer as a basic sensor of the dynamic movements of the gripping clamps, with parallel correlation by a piezoelectric transducer. The grafts for experiments were obtained from 21-paired knees. The measurement was performed at room temperature (21 degrees C) after 24 h of thawing at 4 degrees C. All the specimens were measured for their response to the dynamic tensile load. The maximum strength values were obtained and calculated for the appropriate section area of the specimen. The tensioned strands of the original ACL showed a maximum average load of 1,246 +/- 243 N in the section area of about 30 mm(2) (max. stress 41.3 MPa); the strands of BPTB grafts showed values of 3,855 +/- 550 N in the section area of 80 mm(2) (max. stress 40.6 MPa); the gracilis tendons showed 925 +/- 127 N in the section area of 10 mm(2) (max. stress 95.1 MPa) and the semitendinosuss yielded a result of 2,050 +/- 159 N in the area of 20 mm(2) (max. stress 88.7 MPa). Of all the materials, the original ACL have the lowest strength and stiffness in respect of their biomechanical properties. BPTB grafts showed a slightly higher value of maximum stress, while both the gracilis and semitendinosus tendons showed double the value of maximum load per section area-tensile stress. Two- and four- combined hamstring strands clamped together and equally tensioned with a drop-weight had the combined tensile strength properties of the individual strands within the estimated range of measurement errors. No significant changes in maximum loads/stresses were observed under impact loading conditions. The results of this study demonstrate that equally tensioned four-strand hamstring-tendon grafts have higher initial tensile properties than those in other varieties of samples. From a biomechanical point of view, they seem to be a reasonable alternative procedure for ACL reconstruction.

Aged↗

PubMed2006

Up-regulation of p21WAF1 expression is mediated by Sp1/Sp3 transcription factors in TGFbeta1-arrested malignant B cells.

BACKGROUND: TGFbeta1 has a profound effect on the growth of various mammalian cell types, including B lymphocytes. The inhibitory action of TGFbeta1 is mediated by deactivation of the cell cycle machinery. Several feedback-sensitive pathways determine whether the cells are stopped in G1 phase or allowed to leave G1 phase and enter S phase. Cell cycle-associated molecules, e.g. cyclin-dependent kinase inhibitors (CKIs), may become targets for the inhibitory signaling pathways induced by TGFbeta1. MATERIAL/METHODS: Our experimental DoHH2 cell line model was derived from a patient with malignant non-Hodgkin's lymphoma of follicular origin. The effect of TGFbeta1 on cell cycle progression was studied by flow cytometry. We examined the effect of TGFbeta1 on the expression of p21WAF1 by immunoblotting and RT-PCR. The binding activity of transcription factors to the p21 gene promoter was determined by gel mobility shift assay (GMSA). RESULTS: Our results showed that TGFbeta1 treatment increased the number of cells arrested in G0/G1 phase compared with untreated control cells. Moreover, we found that p21WAF1 expression was significantly up-regulated on the protein level after TGFbeta1 treatment. Similarly to the protein level, the expression of p21 mRNA was increased in TGFbeta1-treated cells. We further examined the binding activity of the Sp family of transcription factors to examine their role in p21WAF1 up-regulation. CONCLUSIONS: The results indicated that p21WAF1 over-expression in TGFbeta1-arrested malignant B cells is mediated by binding of Sp1/Sp3 transcription factors to the (-92/-71), (-77/-58), and (-65/-45) elements of the promoter region of the p21 gene.

B-Lymphocytes↗

PubMed2006

Intraneural perineurioma of the oral mucosa.

A 16-year-old boy presented with an intraneural perineurioma arising from a small nerve in the buccal mucosa. Histologically, the tumour comprised a tortuous proliferation of spindle cells arranged like an onion bulb. To our knowledge this is the third example of an intraneural perineurioma that did not present in a major nerve.

Adolescent↗

PubMed2006

Adrenocortical adenoma with rhabdoid features.

We report a case of an aldosterone producing adrenocortical adenoma with rhabdoid features in a 16-year-old girl. Grossly, the tumor measured 30 mm in diameter and weighed 24 g. Histologically, the tumor was composed of approximately equal parts of tumor cells with rhabdoid features arranged in a solid and trabecular pattern and cells characterized by compact eosinophilic cytoplasm, solid growth with focal necroses, and increased mitotic activity. The lipid-rich tumor cells with ample clear vacuolized cytoplasm represent a minor component. Immunohistochemically, all the tumor cells showed the same results and were positive for vimentin, synaptophysin, Melan A, and alpha-inhibin. Cytokeratin CAM 5.2 was positive only focally. Chromogranin A, actin, alpha-actin, S100 protein, EMA, and cytokeratin AE1/AE3 were negative. Rhabdoid features have been described in many tumors of variable histogenesis; however, to the best of our knowledge, the presence of rhabdoid phenotype has never been described in either adrenocortical adenoma or carcinoma.

Adolescent↗

PubMed2005

Molecular diagnosis of synovial sarcoma: RT-PCR detection of SYT-SSX1/2 fusion transcripts in paraffin-embedded tissue.

BACKGROUND: Synovial sarcomas comprise up to 10 percent of malignant soft tissue tumors, and most are characterized by the chromosomal translocation t(X;18) (pl 1.2;q11.2), which results in the expression of SYT-SSX fusion transcripts. These tumors include two major histological subtypes, biphasic and monophasic. Diagnosing biphasic synovial sarcomas does not usually pose a problem, whereas the monophasic spindle-cell form can be difficult to distinguish from other spindle-cell neoplasms using histological and immunohistochemical profiles only. MATERIAL/METHODS: We investigated the presence of SYT-SSX1/2 chimeric RNA in tumors from 7 patients. We applied amplification of the specific fusion transcripts by reverse transcriptase-polymerase chain reaction (RT-PCR) in fresh, frozen tumors. We also developed a method useful for RT-PCR SYT-SSX fusion transcript detection in formalin-fixed, paraffin-embedded tissue. RESULTS: We found that both histological subtypes of synovial sarcoma were SYT-SSX positive. Moreover, we observed a correlation between histological subtype and type of SYT-SSX fusion transcript. Biphasic synovial sarcoma expressed the SYT-SSX1 fusion transcript, whereas the monophasic subtype expressed the SYT-SSX2 fusion transcript. CONCLUSIONS: The detection of SYT-SSX1/2 fusion transcripts by RT-PCR is a valuable diagnostic marker of synovial sarcoma which can be used for the reclassification of cases whose diagnosis is difficult by routine methods.

Adult↗

PubMed2004

Granular cell basal cell carcinoma.

A 69-year-old woman presented with a 2-year history of a slowly growing tumour on the nose. The clinical diagnosis was basal cell carcinoma (BCC) and a complete excision was performed. Histologically, the tumour had the general features of a BCC but with sheets and nests of cells with granular cytoplasmic changes in the centre of the lesion. A pathological diagnosis of granular cell BCC was made. On immunohistochemical examination, the tumour cells were Ber-EP4, cytokeratin AE1/AE3 and cytokeratin CAM 5.2 positive but S100 protein negative. Only the granular cells were CD68 antigen (monoclonal antibody KP1) positive.

Adult↗

PubMed2003

Division of lymphatic vessels at varicocelectomy leads to testicular oedema and decline in testicular function according to the LH-RH analogue stimulation test.

OBJECTIVES: To study the andrological outcome of the division of testicular lymphatic vessels at varicocelectomy in children and adolescents. METHODS: Testicular size and basal and stimulated luteinizing hormone (LH) and follicle-stimulating hormone (FSH) values were determined prospectively in 86 patients with left unilateral varicocele grades II-III. 22 patients underwent lymphatic non-sparing surgery (LNS group), 10 of them with artery sparing (LNS/AS) and 12 without artery sparing (LNS/ANS), 23 patients underwent lymphatic sparing repair (LS group) and 41 patients were treated conservatively (NT group). RESULTS: The LNS group demonstrated significantly greater left testicular enlargement at six weeks and one year following repair, left testicular hypertrophy developed in 31.8% and hydrocele in 22.7% of patients. Marked oedema of intertubular tissue and a varying degree of tubular injury was observed in boys surgically treated for hydrocele. In the LS group, neither hypertrophy nor hydrocele developed postoperatively, the LH stimulated values were lower than in LNS/ANS group (p<0.05) and the NT group (p<0.04), the FSH stimulated values were lower than in the LNS/ANS group (p<0.001). CONCLUSIONS: Division of lymphatic vessels at varicocelectomy is associated with an excessive increase in testicular volume due to oedema, and with a reduced testicular function according to higher LH and FSH stimulated values. Preservation of lymphatics is strongly advised in varicocelectomy in adolescents to ensure better andrological outcome.

Adolescent↗

PubMed2003

Large cell neuroendocrine carcinoma of the urinary bladder with lymphoepithelioma-like features.

The group of undifferentiated carcinomas of the urinary bladder encompasses small cell undifferentiated carcinoma, giant cell carcinoma, lymphoepithelioma-like carcinoma (LELC), and large cell neuroendocrine carcinoma (LCNEC). These tumors are either pure or can be associated with other components, such as transitional cell carcinoma, squamous cell carcinoma, and adenocarcinoma. We report a case of LCNEC of the urinary bladder in a 54-year-old woman. Histologically, the tumor showed features of LELC; immunohistochemically, the tumor cells reacted to chromogranin A, NSE, and synaptophysin. In addition to these neuroendocrine markers, tumor cells were positive for cytokeratin CAM 5.2 and AE1/AE3, and there was focal positivity for vimentin. In situ hybridization for the detection of Epstein-Barr virus was negative. Despite radical cystourethrectomy and six courses of chemotherapy, the patient developed metastases invading the left inguinal lymph nodes 11 months postoperatively. Currently, 16 months postoperatively, the patient has developed metastases spreading into the lymph nodes of the right ischiorectal fossa; therefore, she is receiving a new cyclus of chemotherapy. There are only three previously reported cases of LCNEC of the urinary bladder, and the significance of neuroendocrine differentiation in non-small cell carcinomas at this location remains to be established. However, LELC appears to be a separate clinicopathological entity with sensitivity to chemotherapy and a relatively favorable prognosis. The differentiation between LELC and LCNEC with prominent inflammatory reaction could be of therapeutic relevance. However, in our case, this was possible using immunohistochemistry only.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2003

Pigmented composite paraganglioma-ganglioneuroma of the urinary bladder.

We report a case of a pigmented composite paraganglioma-ganglioneuroma of the urinary bladder in a 70-year-old female. Grossly, the tumor measured 6.5 cm in diameter and had arisen from the base of the urinary bladder. Histologically, the tumor was composed of approximately equal components of paraganglioma and ganglioneuroma, which were partly separated and partly mixed, and intermingled with each other. There were foci of ample dark brown pigmentation in the cytoplasm of chromaffin paraganglioma cells. The pigment was Masson-Fontana-positive and had been bleached by hydrogen peroxide (H2O2). Electron microscopy showed large, abundant, pleomorphic electron-dense granules consistent with neuromelanin. In addition, there were numerous electron-dense neurosecretory-type granules. Neuromelanin, melanin or lipofuscin are occasionally observed in paragangliomas, although the occurrence of these pigments has never been described in a composite tumor originating from either adrenal medulla or extraadrenal paraganglia. To the best of our knowledge, our report represents the first case of pigmented composite paraganglioma-ganglioneuroma and expands the morphological spectrum of these unusual tumors.

Aged↗

PubMed2000

Hemangiosarcoma of the Thyroid Gland. A case report.

OBJECTIVES: The authors described a case of rare histological type of primary thyroid tumor-angiosarcoma. Angiosarcoma generally represents a rare connective tissue tumor in the head and neck region. Its biological behavior is locally aggressive and destructive with a high recurrence rate. METHODS: A case of a rare histological type of primary thyroid tumor -angiosarcoma-has been described including fine needle aspiration biopsy, histology, and autopsy. RESULTS: Irrespective of the complex approach the angiosarcoma of the patient referred to was diagnosed in a radically inoperative stage of the disease. Radiation was therefore applied after the tumor mass was diminished with the partial thyroidectomy and a correct histopathological diagnosis was rendered. Nevertheless, the locally destructive course was followed with a rather rapid spread of the tumor (lymph nodes, bones, lungs, and brain). Autopsy proved with certainty that the thyroid was the primary tumor location. A suspected kidney origin due to an uncertain sonography shadow of this region was excluded with a complete absence of any neoplastic spread of the angiosarcoma in the abdominal cavity at all.

Journal Article↗