The expression of Gal beta 1,4GlcNAc alpha 2,6 sialyltransferase and alpha 2,6-linked sialoglycoconjugates in human brain tumors.

CMP-NeuAc: Gal beta 1,4GlcNAc alpha 2,6 sialyltransferase (alpha 2,6-ST) [EC 2.4.99.1] is developmentally regulated, shows a high degree of tissue specificity, and appears to play a role in oncogenic transformation and metastasis. In the present study, we have performed the first detailed analysis of the expression of alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugates in human brain tumors. We used a polyclonal, monospecific anti-rat alpha 2,6-ST antibody and the alpha 2,6-linked sialic acid-specific lectin, Sambucus nigra agglutinin (SNA) for histochemical studies, and a human alpha 2,6-ST-specific cDNA probe for Northern analysis. Meningiomas, chordomas and craniopharyngiomas frequently expressed alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugates. Among the different meningioma subtypes, meningothelial meningiomas stained more strongly with both anti-alpha 2,6-ST antibody and SNA than the fibroblastic and anaplastic meningiomas. On the other hand, all tumors of glial origin and medulloblastomas were virtually devoid of either alpha 2,6-ST or alpha 2,6-linked sialoglycoconjugate expression. Moreover, very weak to negligible expression of both alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugates was observed in brain metastases. In conclusion, alpha 2,6-ST and alpha 2,6-linked sialoglycoconjugate expression is associated with non-neuroectodermal epithelial-like tumors.

Immunohistochemical demonstration of human carbonic anhydrase isoenzyme II in brain tumours.

Carbonic anhydrase (CA) is a functionally important enzyme in the central nervous system (CNS), where it is involved in the control of the acid-base balance and regulates the production of cerebrospinal fluid (CSF). Isoenzyme II (CA II) is the most widely distributed CA in the CNS, being present in at least myelin, oligodendrocytes, astrocytes and the choroid plexus. This study was undertaken to examine the presence of CA II in different brain tumours from 31 patients. Specific antibodies recognizing CA II were used in immunoperoxidase staining of tumour specimens. Anti-CA I and VI sera and normal rabbit serum were used as controls. CA II-positive staining was observed in all the astrocytic tumours (n = 9), oligodendrogliomas (n = 3) and medulloblastomas (n = 3). The most malignant tumours exhibited the strongest staining. In addition, four acoustic neurinomas, one plexiform neurofibroma, one choroid plexus papilloma, one ependymoblastoma and one subependymoma expressed the enzyme. Meningiomas (n = 4) and neuronal tumours (n = 4), including one dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos), were negative. Anti-CA I, VI and normal rabbit sera showed no specific staining in tumour cells. The presence of CA II in the astrocytomas was confirmed by Western blotting, which revealed a distinct 29 kDa polypeptide band corresponding the CA II. Anti-CA I serum showed similarly a single 29 kDa band, recognizing the enzyme which is abundantly present in the erythrocytes. The present results demonstrate that despite the malignant transformation of the cells, the expression of CA II is sustained in astrocytic tumours, oligodendrogliomas, ependymal and choroid plexus tumours and tumours of nerve sheath cell origin. Our results suggest that some tumours contain abundant CA II, which might leak into the CSF.

[Changes in arginase activity during neurinoma growth]. / Izmenenie aktivnosti arginazy v protsesse rosta nevrinomy.

Arginase activity was studied in the brain and other tissues of the rat at the different periods of neurinoma growth. The activity of the enzyme was considerably activated in the affected hemisphere on the 4th day, in the skin of the head and thigh on the 6th day after tumor transplantation. Elevation in arginase activity in the neoplasm itself was recorded on the 16th day. The data obtained point to the physiological significance of arginase during neurinoma growth.

The histochemical behaviour of zinc-activated tartrate-resistant phosphatase (ZnTP) in early stages of experimental tumors in the rat trigeminal nerve.

The activity of the ZnTP (Felicetti und Rath 1975; Rath and Felicetti 1975) was investigated histo- and biochemically in neurinomas of trigeminal nerves of rats. The tumors were induced by a single transplacental pulse of 30 mg ENU/kg on the 17th day of gestation. The rats were killed at the age of 40 to 160 days. The activity of the ZnTP is demonstrated histochemically by a coupling azo dye technique with 1-naphthylphosphate after Rath and Felicetti (1975) as well as a lead nitrate method with 4-nitrophenyl phosphate at the age of 40 to 140 days. Biochemical investigations of the trigeminal nerves are performed at the age of 140 and 160 days only. The separation of ZnTP is carried out by isoelectrofocusing in polyacrylamide gels after Felicetti and Rath (1975). Together 14 neurinomas are found in the trigeminal nerves of 53 rats. All neurinomas show a high activity of the ZnTP. The ZnTP activity is absent in normal Schwann cells. Three trigeminal nerves of rats subjects to the transplacental pulse of ENU harbour small foci of ZnTP activity without detectable neoplastic cell proliferation. Similar spots of enhanced ZnTP activity have never been found in control rats. This rises suspicion that the neoplastic proliferation of cells is preceded by the activation of ZnTP.

[The effect of ethylnitrosourea in the activity of the NAD-linked glycero-3-phosphate dehydrogenase in the Vth nerve of developing rats and its relation to myelination and tumour induction (author's transl)]. / Der Einfluss von Athylnitrosoharnstoff auf die Aktivität der Nad-abhängigen L-alpha-Glyzerin-3-Phosphatdehydrogenase während der Myelinisierung und Tumorinduktion im N. trigeminus der Ratte.

The activity of NAD-linked L-alpha-glycero-3-phosphate dehydrogenase (E.C. 1.1.1.8.) in the Vth nerve from albino rats treated with a single subcutaneous injection of ethylnitrosourea in the first day of life and from controls was determined biochemically in 10 different age groups ranging from 7 to 70 days. The specific activities of the controls rise rapidly from the 7--35 days of life and remain there after almost at the same level. The activity of the ENU treated animals is significantly lower than that of the controls and reaches only at the age of 63 days the values of the 35 days old untreated animals. About 26% of the activity values of the treated animals are below the lower confidence limit of the controls.