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Biomedical subjects

Jindrich Martínek

Publications and source records attributed to Jindrich Martínek.

7 recordsLinked to original sources
PubMed2005

Expression of nitric oxide synthases in parathyroid gland adenoma and parathyroid gland hyperplasia.

OBJECTIVE: The aim of the presented study was to perform the immunohistochemical detection of endothelial (eNOS) and inducible (iNOS) isoform of nitric oxide synthase in the adenomatous and hyperplastic parathyroid gland in relation to the apoptotic process. DESIGN AND SETTING: Tissue samples from 12 patients with parathyroid gland adenoma (PGA) and 10 patients with secondary parathyroid gland hyperplasia (PGH) were collected during surgery at the Department of Otorhinolaryngology and Head and Neck Surgery of The First Faculty of Medicine in Prague. METHODS: Three-step immunoperoxidase reaction on acetone-fixed cryostat sections was performed using both polyclonal and monoclonal antibodies against eNOS and iNOS. The detection of apoptotic cells was done using antibody against cleaved caspase-3 as an apoptotic marker. RESULTS: The immunoreactivity to eNOS antibody was observed in the endothelial lining of vessels in PGA, PGH and in the rim of normal parathyroid gland adjacent to PGA sample. Variable expression of eNOS was confirmed in arteries, arterioles, capillaries and veins in the glandular parenchyma as well as in the surrounding connective tissue. There was no iNOS immunoreactive cell detected in any examined sample. No apoptotic cells were detected. MAIN RESULT: Our findings confirm that eNOS is regularly expressed in the vasculature of PGA and PGH. CONCLUSION: eNOS observed in the vasculature of the enlarged parathyroid glands can serve as a factor that contributes to the viability of hypertrophic pathologic tissue. The lack of stimulating signals may be a reason for negative iNOS detection and negligible apoptotic rate.

Adenoma↗
PubMed2004

Altered spermatogenesis in the hypodactylous rats.

Germinal epithelium of seminiferous tubules in adult, infertile hypodactylous males displays significant reduction in the number of germ-line cells. Detection of apoptosis in the germ-line cells during postnatal differentiation was performed to elucidate the mechanism of the decreased number of germ cells in the testes of adult rats. Evaluation of DNA fragmentation and expression of activated caspase-3 in germ cells did not confirm marked germ cell death during the onset of spermatogenesis as a main cause of significant reduction of germ cells in Hd/Hd testes of adult males. The primary cause of spermatogenesis defect seems to be rather associated with a disorder in the cell cycle regulation and interrelation of germ-line cells with Sertoli cells.

Animals↗
PubMed2004

Serum levels of growth factors HGF (Hepatocyte Growth Factor), TGFbeta1 (transforming growth factor beta1) and IGF-I (Insulin Like Growth Factor I) in parathyroid tumors.

INTRODUCTION: HGF (Hepatocyte Growth Factor), TGFbeta1 (Transforming Growth Factor beta1) and IGF-I (Insulin Like Growth Factor I) are cytokines that are involved in the parathyroid tumors formation and growth. We tried to determine, if there are changes and relationships in the production of these cytokines by tumor cells of parathyroid tumors. MATERIAL AND METHODS: We determined concentrations of HGF, TGFbeta1 and IGF-I in serum from peripheral blood of 16 patients with parathyroid adenoma and of 8 patients with parathyroid secondary hyperplasia before and after parathyroidectomy. Results were compared with serum levels in healthy people. RESULTS: Both preoperative and postoperative HGF serum levels in patients with parathyroid adenoma and secondary hyperplasia are significantly higher than in healthy people. Preoperative and postoperative serum levels of TGFbeta1 in parathyroid adenoma and postoperative TGFb1 serum levels in parathyroid secondary hyperplasia are higher, compared with those in the healthy population and in parathyroid secondary hyperplasia preoperatively. There are no significant differences of IGF-I serum levels among the all investigated groups of patients. CONCLUSIONS: Changes in the growth factors production by parathyroid tumor cells are reflected by their concentrations in peripheral blood. The elevation of HGF serum levels in patients with parathyroid adenoma and hyperplasia can be explained by very high HGF production by tumor cells. Nevertheless, there is no decrease of HGF serum levels after the parathyroidectomy. That may be the result of the extratumoral production of this cytokine. Also TGFbeta1 and IGF-I serum levels indicate high possibility of the extratumoral production of these cytokines. Higher postoperative IGF-I serum levels (but not significantly) in parathyroid secondary hyperplasia are in accordance with its bone production.

Adenoma↗
PubMed2003

Nitric oxide synthase inhibitors modulate lipopolysaccharide-induced hepatocyte injury: dissociation between in vivo and in vitro effects.

Effects of endotoxemia-induced NO production on rat liver and hepatocytes in culture were investigated. Rats were treated intraperitoneally with saline, lipopolysaccharide (LPS, 10 mg/kg), L-nitroarginine methyl ester (L-NAME)+LPS, aminoguanidine (AG)+LPS, FK 506+LPS, S-nitroso-N-acetyl penicillamine (SNAP)+L-NAME+LPS and SNAP+FK 506+LPS. Mortality, hepatocyte viability and liver function test were estimated. Liver morphology was observed by light and electron microscopy. Hepatocyte cultures were treated with LPS, cytokine mixture (CM) with or without FK 506, L-NAME or AG. Hepatocyte function and inducible form of NOS (iNOS) expression were evaluated. Twenty-four hours after treatments with saline, LPS, L-NAME+LPS, AG+LPS, FK 506+LPS, SNAP+L-NAME+LPS and SNAP+FK 506+LPS, rat mortalities were 0%, 10%, 48%, 8%, 20%, 38% and 0%, and hepatocyte viabilities were 93+/-3%, 80+/-3%, 52+/-8%, 88+/-1%, 70+/-3%, 80+/-4% and 82+/-3%, respectively. AG+LPS or L-NAME+LPS administration was followed by excessive vacuolization of hepatocytes with lesions in the intermediary lobule zone characterized by features of secondary necrosis as a continuation of apoptotic processes. SNAP+L-NAME+LPS resulted in a well-preserved structure of central vein lobules with sparse signs of apoptosis. Treatment with LPS or CM increased iNOS expression in hepatocyte culture, which was inhibited by L-NAME, FK 506 or AG. AG reduced LPS-induced rise in alanine aminotransferase leakage. LPS-induced NO exerts cytoprotective effects in vivo, while LPS-induced NO in vitro appears to be toxic. Based on the data of this report, one cannot use in vitro results to predict in vivo responses to LPS-induced NO production. The pharmacological modulation of iNOS expression or NO production in vivo or in vitro, therefore, by the development of specific NO donors or inhibitors is promising for improvement of hepatocyte functions under the two experimental conditions, respectively.

Alanine Transaminase↗