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Journal Article 2005; 26(4): 373-376 PubMed PMID: 16136006 Citation  Keywords:  Adenoma:blood supply, Apoptosis, Humans, Hyperplasia, Immunoenzyme Techniques, Neovascularization, Pathologic:metabolism, Nitric Oxide Synthase Type II:metabolism, Nitric Oxide Synthase Type III:metabolism, Parathyroid Glands:blood supply, Parathyroid Neo.   

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....

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Journal Article 2005; 26(4): 413-418 PubMed PMID: 16135999 Citation  Keywords:  Animals, Cell Division:drug effects, Cell Line, Culture Media, Conditioned:pharmacology, Endothelial Cells:cytology, Humans, In Vitro Techniques, Mice, Neovascularization, Pathologic:metabolism, Pituitary Gland:cytology, Rats, Vascular Endothelial Growth .   

OBJECTIVES: The process of neoangiogenesis plays a key role in development and progression of solid tumours. The formation of new blood vessels different from the portal network system is important for pituitary tumour formation. The pivotal role of activated endothelial cells in angiogenesis was well documented. The degree of endothelial cells stimulation depends on the angiogenic activity of the tumorous cells. The aim of the study was to elucidate the angiogenic properties of the lactosomatotrophic pituitary cell line.

MATERIAL AND METHODS: The study was carried out on the mouse endothelial HECa10 cell line subjected to medium obtained from the culture of rat lactosomatotrophic pituitary GH3 cell line. The endothelial cell growth was measured using the modified colorimetric method EZ4Y detecting the viable cells. The secretion of vascular endothelial growth factor (VEGF) to GH3 cells conditioned medium was assessed by immunoenzymatic method.

RESULTS: It was shown that the exposure of endothelial cells to pituitary tumorous conditioned medium significantly stimulated the cellular growth after 24 and 48 hours of incubation. Moreover, the concentration of VEGF in GH3 conditioned medium occurred to be 13 times higher than in the control medium.

CONCLUSION: Our results indicate the angiogenic activity of lactosomatotrophic GH3 cell line and suggest the role of VEGF in pituitary tumorous angiogenesis....

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