Up-regulation of urokinase-type plasminogen activator in squamous cell carcinoma of human larynx.

The expression of urokinase-type plasminogen activator (uPA) was investigated in squamous cell carcinoma of the human larynx. For this purpose, tissue extracts from 25 matched samples of normal mucosa and neoplastic larynx were compared for the levels of uPA activity as evaluated by a chromogenic PA assay and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) zymography. Also, uPA antigen was quantified by enzyme-linked immunosorbent assay (ELISA) in 19 cases. The results demonstrate a significant increase in the levels of uPA activity and protein in tumour tissue extracts, more pronounced in tumours with lymph node metastases. Immunohistochemistry performed on 70 biopsies showed that uPA positivity is present both in neoplastic cells and in fibroblast-like cells and macrophages. However, depending on the histological grading and invasive capacity of the tumour, a pronounced intra- and intertumoral heterogeneity in uPA staining was observed. In situ hybridisation confirmed the presence of uPA mRNA in both tumour and stromal cells. The present study provides experimental evidence for a role of uPA in the invasive growth of human laryngeal carcinoma.

Development of chicken embryos exposed to an intermittent horizontal sinusoidal 50 Hz magnetic field.

The effects of intermittent exposure (2 h on/22 h off) to a 200 microT horizontal, sinusoidally oscillating (50 Hz) magnetic field were studied in 210 fertilized chicken eggs. Two hundred ten control eggs (sham-exposed) were incubated in the same chamber as the experimental eggs. Chick embryos were examined for developmental anomalies and maturity stage after 48 h of incubation. Immunohistochemical analysis of extracellular membrane components (laminin, fibronectin, and type IV collagen) were conducted on day 7 and histological examinations for malformations of brain, liver, and heart, on days 7, 12, and 18 of incubation. Furthermore, egg fertility and egg weights were evaluated on days 2, 7, 12, and 18. The investigation also measured the body weight of chickens for 90 days from hatching and included histological analysis of body organs. Each variable was investigated blind. Statistical comparison between exposed and sham-exposed values did not show significant differences in any of the variables investigated. Thus, it appears that the exposure of embryos to an intermittent 200 microT magnetic field at 50 Hz does not cause developmental anomalies, changes in maturity stage, alterations in distribution of extracellular membrane components, or malformations in the brain, liver, or heart. Moreover, there were no differences in body weight, morphology, or histology of central nervous system, liver, heart, or testis in 90-day-old chickens hatched from exposed in comparison to sham-exposed eggs.