Diagnostic value of WT1 in neuroepithelial tumours.

AIMS: Currently, clinical trials using WT1 (Wilms tumour gene) peptide vaccines are conducted in haematopoietic malignancies and solid cancers. Single reports showed that the Wilms tumour gene product WT1 is also expressed in astrocytic neoplasms. Our aim was to investigate WT1 expression in a large cohort of various neuroepithelial tumours of different World Health Organization (WHO) grades and in normal central nervous system (CNS) tissue specimens to test its potential value as a diagnostic marker. METHODS: Specimens were assessed by RT-PCR, Western blotting and immunohistochemistry. The samples investigated in our study consisted of 334 human neuroepithelial tumours, among those 33 oligodendrogliomas, 219 astrocytomas (including 105 glioblastomas) and 47 ependymomas. RESULTS: Our results showed a de novo WT1 expression in neuroepithelial tumours. In diffuse astrocytomas and ependymomas, WT1 expression increased significantly with the grade of malignancy. In contrast, no significant difference was seen between WHO grade-II and -III oligodendrogliomas. Controlling for WHO grade, the comparison of oligodendrogliomas with ependymal and astrocytic tumours showed higher expression values for the latter. CONCLUSIONS: Our study shows that WT1 is expressed de novo in numerous neuroepithelial tumours and increases with the grade of malignancy. These results suggest an important role of WT1 in tumourigenesis and progression in human brain tumours.

De novo erythropoietin receptor (EPO-R) expression in human neoplastic glial cells decreases with grade of malignancy but is favourably associated with patient survival.

The erythropoietin receptor (EPO-R) is mainly known as a regulator of erythropoiesis. However, recent studies revealed that the EPO-R is not exclusively expressed in haematopoietic tissues but also in various cancer cell types and normal tissue such as the central nervous system (CNS). EPO-R is up-regulated under hypoxia and is able to counteract the deleterious effects of hypoxia on tumour growth, metastasis and treatment resistance. Therefore, the EPO-EPO-R signalling pathway is considered as a possible target for tumour treatment. Here, we investigated brain tumour samples obtained from patients between 1993 and 2003 to study EPO-R expression in vivo. Tissue samples included 194 gliomas of different WHO grades, additionally 25 infiltration zone samples and 31 relapses of WHO grade IV glioblastomas as well as 23 normal CNS tissue specimens to address the in vivo situation. Immunohistochemistry of the tissue microarray samples revealed significantly higher levels of EPO-R expression in neoplastic glial cells compared with glial cells derived from normal brain. EPO-R expression showed a highly significant decrease from low- to high-grade gliomas. Age-stratified Kaplan-Meier analysis revealed longer survival for patients exhibiting high EPO-R status in high-grade gliomas. Our results show a grade-dependent EPO-R down-regulation and might contribute to the understanding of high-grade glioma resistance to radio- and chemotherapy as both were shown to be improved by a well functioning EPO-EPO-R pathway in previous studies. Further studies are needed to investigate to what extent the decreased mortality in age-stratified patient groups with high EPO-R levels reflects a direct beneficial role of EPO-R expression.

Differential microglial regulation in the human spinal cord under normal and pathological conditions.

As the primary intrinsic immune effector cells of the central nervous system, microglia are involved in virtually all pathological processes of the brain and spinal cord including inflammatory, neurodegenerative, traumatic, neoplastic and vascular diseases. Despite this important role, there is a lack of data concerning microglial distribution and protein expression in the human spinal cord. In this study, we immunohistochemically investigated 10 normal human spinal cords to establish reference data and compared these results with 15 pathological human spinal cords deriving from distinct pathologies. Each spinal cord was evaluated at eight different levels for three white and two grey matter areas for both constitutive (MHC-II, CD68, IL-16, AIF-1, LCA, CD4) and reactive (MRP-8, MRP-14) microglial antigens. Whereas previous studies revealed significant regional differences in microglial distribution and protein expression in human brain, normal spinal cord displayed a uniform expression pattern, reaching levels of up to 17% MHC-II positive cells of the total cell population. This datum formed the basis for the further evaluation of microglia expression levels in pathological spinal cords, where levels of up to 45% positive cells were observed. Our results represent important reference values for future neuropathological diagnostic and therapeutical approaches in spinal cord pathologies.

A long-term toxicity test comprising reproduction and growth of zebrafish with 4-chloroaniline.

This study describes a long-term test over three generations, using zebrafish (Brachydanio rerio) as the test species and concentrations of 1, 0.2, and 0.04 mg/L 4-chloroaniline (CA) as a model substance. The effect of the compound on the ecologically important parameters reproduction and growth was the focus of interest. Reduction in egg release by fish raised under CA was the most sensitive parameter in the test. Compared to the toxic threshold concentration for growth (0.4 mg/L), egg release was affected by a ten-fold lower concentration (0.04 mg/L). This study demonstrates that a long-term test is still the most appropriate method to assess the chronic toxicity of a substance on fish. A chronic toxicity test is proposed which comprises two generations, with the zebrafish as test species.

Investigations on the origin of two radiation-induced compounds in irradiated meat.

After irradiation with 0.5 Mrad or higher doses, a radiation-induced ninhydrin-positive compounds was found in the muscle tissue of warm-blooded animals. In carp muscle another compound called X was formed. The origin of these two compounds was investigated. Irradiation of various amino acids and related compounds showed that substance Y is formed from the dipeptides carnosine and anserine, which are present in muscle tissue of warm-blooded animals unusually high concentrations. In carp muscle containing relatively high levels of histidine, but only low concentrations of anserine as the only dipeptide, histidine furnished compound X. This compound was found to be relatively stable in acid medium. After acid hydrolysis of irradiated carnosine solutions and of extracts of irradiation muscle tissue from warm-blooded animals, compound Y was no longer observed, but another compound appeared that was similar to X with regard to colour and migration properties during high-voltage electrophoresis and column chromatography.