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Copyright of Česká a Slovenská Neurologie a Neurochirurgie is the property of Czech Medical Association of JE Purkyne and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper is a retrospective analysis of a 33 patient cohort with dia gnosis of glioblastoma multiforme treated us ing gam ma knife stereotactic radiation ther apy fol low ing surgical resection and fractionated radiation ther apy. Over al l, 35 stereotactic radiation procedures were performed. Within this group, we differentiated patients who benefited from these procedures - we managed to stabilise or achieve remis sion of the dis ease in 13 cases (37%) in a 3 month fol low-up and in 6 cases (18%) in a 6-month fol low-up. Long-term remis sion of this highly malignant tumor us ing gamma knife ther apy was achieved in 4 patients. [ABSTRACT FROM AUTHOR]

γ-Glutamyltranspeptidase (GGT, syn. γ-Glutamyltransferase) and dipeptidylpeptidase-IV (DPP-IV) activity participates in metabolic and growth control of normal and tumor cells by processing biologically active peptides. Here, we report on up-regulation of these enzymes in human brain gliomas determined by catalytic enzyme histochemistry and immunocytochemistry. Higher activity of GGT was found in 50%, 68% and 81% of WHO grade II, III and IV tumors, respectively. The process started at/near the microvasculature, from where it spread to the parenchyma. On average, the enzyme activity in grade II, III and IV gliomas exceeded controls 2.0, 3.0 and 3.5-fold, respectively. Up-regulation of DPP-IV-like activity also started at the microvasculature, but mainly in pericytes and mononuclear-like cells around the vessels and dispersed in the parenchyma. Marked elevation of this enzyme activity, comprising also tumor parenchyma, occurred only in grade IV glioblastomas (65% patients; 3.6 times above controls) which can, therefore, help in their differentiation from grade III gliomas. The increase of total DPP-IV-like activity also included its two enzymatic homologs, the canonical DPP-IV/CD26 and FAP-1α. The increase in GGT is supposed to be a tumor grade dependent response of microvasculature and tumor astrocytes to stress induced by tissue hypoxia and/or the metabolic aberrancies. The increase in DPP-IV-like activity in high-grade tumors can be attributed to inflammatory/scavenging processes performed by the mononuclear-like cells and, in glioblastomas, also to regressive changes in the structure and function of the microvasculature and tumor parenchyma, including astrocyte stress response. The inverse relationship between DPP-IV-like activity and Ki67 in most glioblastomas and shorter survival time of patients with low activity of this enzyme also suggest its anti-oncogenic effects.