Synergistic anti-tumor effect of ultrasound and hematoporphyrin on sarcoma180 cells with special reference to the changes of morphology and cytochrome oxidase activity of tumor cells.

This study is aimed at evaluating the inhibitory effects of the association of hematoporphyrin and ultrasound at variable intensities with a fixed frequency of 1.1MHz in tumor nodules. Specifically, the effects were studied both in solid and ascitic S180 tumors transplanted in mice by clinical, cytochemical and ultrastructural evaluation. The results indicated that the use of hematoporphyrin alone had no significant effect on destroying tumor cells. The ultrasound alone had little effect. Interestingly, the inhibition was much more effective when hematoporphyrin was combined with ultrasound. The inhibition was 3 times better than ultrasound alone and 8 times better than hematoporphyrin used alone. Our results also indicated that the changes on cell structure and cytochrome oxidation activity are important factors that could inhibit tumor cell growth and induce cell death. Apoptosis of tumor cells could be induced by hematoporphyrin. Our study investigated the killing mechanism on S180 tumor cells by using hematoporphyrin and low frequency ultrasound at cell, tissue and individual level.

Piezoelectric crystal for sensing bacteria by immobilizing antibodies on divinylsulphone activated poly-m-aminophenol film.

A polymer sorbent formed at the surface of gold-plated piezoelectric crystal by anodic oxidation of m-aminophenol was investigated by voltammetric, FTIR techniques for antibody coupling after activation by divinylsulphone. A novel film with increased capacity for immobilizing antibodies was obtained using phloroglucinol to modify poly-m-aminophenol via divinylsulphone. Compared with the dip-coating methods using polyethylenimine and (gamma-aminopropyl)trimethoxysilane, this new technique gave more reproducible results for the immobilization of antibody from sample to sample due to the improved homogeneity and reproducibility of the coating. With present modification method, a piezoelectric immunosensor was developed for the detection of Salmonella enteritidis. A detection limit of 1x10(5) cells ml(-1) and an assay time of 25 min were achieved.