Therapeutic effects of photocatalytic nano-TiO₂on human nasopharyngeal carcinoma xenografts in nude mice / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To study the therapeutic effect of photocatalytic nano-TiO₂ on nasopharyngeal carcinoma xenograft in nude mice and underlying mechanism.</p><p><b>METHODS</b>Nude mice bearing human nasopharyngeal carcinoma xenograft were randomly divided into six groups: nano-TiO₂ + UV irradiation (with gradient concentration of nano-TiO₂); nano-TiO₂ alone and UV irradiation alone and blank control. The nano-TiO₂ suspension was injected into xenografts, and 24 h after UV light with the wave length of 330 - 400 nm, all the xenografts were removed and sectioned for HE staining. Ultrastructure and apoptosis of tumor cells in the xenografts were observed by transmission electron microscope (TEM). The expression of Caspase-3 was examined immunohistochemical staining and the apoptosis was detected with TUNEL.</p><p><b>RESULTS</b>Pathological analysis showed significant inflammatory responses (grade II and III) with local necrosis occurred in tumor tissues after nano-TiO₂ photodynamic therapy, but not in the negative control and blank control. TEM showed the nano-TiO₂ particles entered into the cytoplasm and the nucleus of tumor cells and many tumor cells had morphological changes for apoptosis. Significant positive expression of Caspase-3 and TUNEL-positive cells were found in the the xenografts with the treatments of nano-TiO₂ + UV irradiation compared to control (P < 0.01), which were enhanced with the increases in nano-TiO₂ concentration (P < 0.01).</p><p><b>CONCLUSION</b>Photocatalytic nano-TiO₂ can inhibit the growth of nasopharyngeal carcinoma xenograft in nude mice by inducing Caspase-3 expression and apoptosis in the tumor cells.</p>

Ultrastructural and immunohistochemical studies on Trichomonas vaginalis adhering to and phagocytizing genitourinary epithelial cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Trichomonas vaginalis (T. vaginalis) belongs to a common sexually transmitted disease pathogen causing genitourinary trichomoniasis in both sexes. We investigated the pathogenetic mechanism of genitourinary trichomoniasis.</p><p><b>METHODS</b>Cultured T. vaginalis bodies were injected into the vaginas of rats, or incubated with genitourinary epithelial cells of female subjects, male subjects, and sperm. The ultrastructural and microscopic changes were observed via transmission and scanning electron microscopy and through microscopic histochemistry.</p><p><b>RESULTS</b>Groups of T. vaginalis adhered to PAS positive columnar cells at the surface of stratified epithelium in the middle and upper portions of the vaginas. They also traversed under these cells. The parasites were shown to be PAS, cathepsin D, and actin positive, and they could release hydrolase into the cytoplasm of adhered epithelial cells. In the amebiform T. vaginalis, microfilaments were arranged into reticular formation. Similar phenomena were found during the interaction of T. vaginalis with host cells, both in vitro and in vivo. Usually several protozoa adhered to an epithelial cell and formed polymorphic pseudopodia or surface invaginations to surround and phagocytize the microvilli or other parts of the epithelial cytoplasm. Adhesion and phagocytosis of sperm by the protozoa occurred at 15 - 30 minutes of incubation. Digestion of sperm was found at 45 - 75 minutes and was complete at 90 - 105 minutes.</p><p><b>CONCLUSIONS</b>T. vaginalis tends to parasitize at the fornix of the vagina, because this is the site where columnar cells are rich in mucinogen granules and their microvilli are helpful for adhesion and nibbling. T. vaginalis possesses some invading and attacking abilities. Shape change, canalization, encystation, phagocytosis, digestion, the cell coat, cytoskeleton, and lysosome all play important roles in the process of adhesion. They have two methods of phagocytosis: nibbling and ingestion. Genitourinary epithelium may be injured directly by the digestive action of hydrolases, phagocytosis, and the mechanical action of pseudopodia.</p>

The quantitative analysis of protein particles of erythrocyte membrane from Duchenne muscular dystrophy patients and the gene carriers / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To study the changes of the intramembrane protein particles of erythrocyte from Duchenne muscular dystrophy (DMD) patients and the gene carriers and to explore the pathogenesis of DMD and the diagnostic value of erythrocyte freeze-fracture technology.</p><p><b>METHODS</b>The fixed erythrocyte mass was treated to form replica membrane by means of the freeze-fracture technology. Then the replica membrane was observed and a picture was taken under electron microscope. The protein particles of extracellular face(EF) and protoplasmic face(PF) per square were counted. The statistical comparative analysis was performed.</p><p><b>RESULTS</b>The protein particle counts of EF face and PF face of erythrocyte membrane from DMD patients and DMD carriers decreased obviously in comparison with the normal control group (P<0.001).</p><p><b>CONCLUSION</b>The erythrocyte freeze-fracture electron microscopic technology may serve as a method for accessory examination of diagnosing DMD patients and a method for detecting DMD carriers. This investigation material supplies reliable evidence for the theory of the systemic membrane defect of DMD.</p>