Immunohistochemical localization of glutathione S-transferase-pi in human colorectal polyps.

AIM: To investigate the distribution of the placental form of glutathione-S-transferase (GST) in colon polyps in order to evaluate the role of GST-pi in these tissues. METHODS: Sixteen polyp tissues removed at colonoscopy were examined. Tissues were investigated histologically and ultrastructurally. GST-pi expression was also analysed immunohistochemically, using peroxidase anti-peroxidase (PAP) method and immunogold labelling method, for light and electron microscope respectively. RESULTS: All polyp tissues examined were adenoma of low, mild and high- grade dysplasia as shown in the histopathological reports. Nevertheless, the examination of the above specimens with electron microscope revealed that 3 of 9 adenoma of mild dysplasia had ultrastuctural features similar to high-grade dysplasia adenoma. GST-pi was variably expressed in adenoma, with the lowest relative levels occurring in low-grade adenoma and the highest levels found in high-grade adenoma. GST-pi was located mainly in undifferentiated epithelial cells. GST-pi positive particles were found in the cytoplasm and especially in the nucleus adjacent to the nuclear membrane of these cells. CONCLUSION: The overexpression of GST-pi in mild-grade adenomas with significant subcellular changes and in the majority of high-grade dysplasia adenoma suggests that this might be related to the carcinogenetic proceeding. Immunohistochemical localization of GST-pi in combination with ultrastructural changes indicate that GST-pi might be a sensitive agent for the detection of preneoplastic transformations in adenoma.

The effect of negative pressure therapy on the femoral vein blood flow and wall structure.

Negative pressure therapy has been recently used for managing lymphatic or infective groin complications. The aim of this study was to investigate any possible association between application of negative pressure therapy in the groin area and deep-vein thrombosis. Acute surgical wounds were created at the inguinal areas in 7 pigs. Different negative pressures ranging from -50 to -200 mmHg were applied directly over the femoral vessels, and blood flow alterations were studied using a Doppler ultrasound. Femoral vein specimens were also removed for histological examination after 12 hours of therapy. It has been demonstrated that negative pressure therapy does not significantly alter the baseline lower limb venous return. Histology demonstrated several changes, which are associated with vein thrombogenesis. The hemodynamic and pathological findings still leave a potential for thrombogenic effects of negative pressure therapy and warrant care to protect the femoral veins, with the use of thrombosis prophylaxis measures.