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Background: Modern research has provided new insights into the biological mechanisms of noise-induced hearing loss, and a number of studies showed the appearance of increased reactive oxygen species (ROS) and reactive nitrogen species (RNS) during and after noise exposure. This study was designed to investigate the noise exposure induced nitrotyrosine change and the mechanism of outer hair cells death in guinea pig cochlea., Method: Thirty guinea pigs were used in this study. The experimental animals were either exposed for 4 hours per day to broadband noise at 122 dB SPL (A-weighted) for 2 consecutive days or perfused cochleae with 5 mg/ml of the SIN1 solutions, an exogenous NO and superoxide donor, for 30 minutes. Then the cochleae of the animals were dissected. Propidium iodide (PI), a DNA intercalating fluorescent probe, was used to trace morphological changes in OHC nuclei. The distribution of nitrotyrosine (NT) in the organ of Corti and the cochlear lateral wall tissue from the guinea pigs were examined using fluorescence immunohistochemistry method. Whole mounts of organ of Corti were prepared. Morphological and fluorescent changes were examined under a confocal microscope., Results: Either after noise exposure or after SIN1 perfusion, outer hair cells (OHCs) death with characteristics of both apoptotic and necrotic degradation appeared. Nitrotyrosine immunolabeling could be observed in the OHCs from the control animals. After noise exposure, NT immunostaining became much greater than the control animals in OHCs. The apoptotic OHC has significant increase of nitrotyrosine in and around the nucleus following noise exposure. In the normal later wall of cochleae, relatively weak nitrotyrosine immunolabeling could be observed. After noise exposure, nitrotyrosine immunoactivity became stronger in stria vascularis., Conclusion: Noise exposure induced increase of nitrotyrosine production is associated with OHCs death suggesting reactive nitrogen species participation in the cochlear pathophysiology of noise-induced hearing loss.

Background: The research of cancer in patients on hemodialysis (HD) in China has not been reported. The aim of this study was to investigate the clinical and histological features and outcomes of cancer in Chinese HD patients., Methods: The study subjects were 49 cancer patients (1.4%) out of 3448 end stage renal disease (ESRD) patients maintained on HD at China-Japan Friendship Hospital from October 1997 to July 2011., Results: Urinary tract cancer (74%) was the most common followed by gastrointestinal tract cancer (12%), breast cancer (6%), lung cancer (4%), thyroid cancer (2%), and hematologic cancer (2%). Thirty-three patients (67%) had urinary tract transitional cell carcinoma (TCC) and 29 of them had aristolochic acid nephropathy (AAN) as underlying disease. Death occurred in eight patients out of 49, and the survival rate of HD patients with cancer was similar to those without cancer (P = 0.120)., Conclusion: The urinary tract TCC is the most common cancer in HD patients with AAN in one of the centers of northern China.

Background: Beta-catenin, a 92 kDa protein that binds to the cytoplasmic tail of E-cadherin, has an essential role in intercellular adhesion and signal transduction. Aberrant expression of beta-catenin has been associated with progression and metastasis of various human cancers. The aim of this study was to elucidate the expression pattern of beta-catenin in primary oral squamous cell carcinoma and examine the correlation between beta-catenin expression and tumor differentiation, histological grade and lymph node status as well as its clinical significances., Methods: Seventy-six patients with oral squamous cell carcinoma and sixteen metastatic lymph nodes were studied. The beta-catenin expression was determined by immunohistochemical staining. The correlation with clinical, histological data was analyzed statistically., Results: Normal oral epithelium showed strong beta-catenin expression at the cell membrane, but no cytoplasmic or nuclear expression. Different degrees of reduced expression of beta-catenin at the cell membrane were found in 54 cases with squamous cell carcinoma (71%). Cytoplasmic beta-catenin expression was found in 17 tumors (22.4%). Three cases were found with nuclear beta-catenin expression. In sixteen lymph nodes with metastatic squamous cell carcinoma, negative beta-catenin expression at the cell membrane was seen in 13 tumors (81.2%) and weak expression in 3 tumors (18.8%). Statistical analysis showed that there was an inverse correlation between beta-catenin expression and lymph node status and histological grade of tumors., Conclusions: Reduced beta-catenin expression at the cell membrane is clearly associated with lymph node metastasis. A reduced expression of beta-catenin may constitute a hallmark of aggressive biological behavior of squamous cell carcinoma.

Background: Reports are increasingly appearing on the side effects caused by excessive iodine intake. Our objective was to find out whether iodine excess would impair the thyroid function and intelligence of schoolchildren in rural areas of China., Methods: A comparative epidemiological study was made on thyroid function and intelligence of the schoolchildren in the areas of low, moderate or excessive intake of iodine. In the area of low intake of iodine (Panshan, Liaoning province, median urinary iodine (MUI) was 99 microg/L), of moderate intake of iodine (Zhangwu, Liaoning Province, MUI was 338 microg/L) and of excessive intake of iodine (Huanghua, Hebei Province, MUI was 631 microg/L). The numbers of schoolchildren from each area selected to take part in a Chinese version of Raven's Test were 190, 236 and 313, respectively, and then 116, 110 and 112 of them were tested for thyroid function, thyroid autoantibody (TAA) and urinary iodine (UI)., Results: There were no significant differences in the incidences of overt hyperthyroidism, subclinical hyperthyroidism and overt hypothyroidism in Panshan, Zhangwu and Huanghua. But significant differences were found in the incidences of subclinical hypothyroidism (P = 0.001) in these three areas. The incidences of subclinical hypothyroidism in Huanghua and Zhangwu were 4.76 and 3.37 times higher than that in Panshan. TAA were negative in all the schoolchildren with subclinical hypothyroidism except for one. No significant difference was found among the rates of thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb) in these three areas. Mean serum thyroglobulin (TG) value of Huanghua was markedly higher than those of the other two (P = 0.02). Mean serum TG value of Zhangwu was higher than that of Panshan but the difference was not significant. Mean IQ value of the schoolchildren in Huanghua was markedly higher than that for Zhangwu (P = 0.001). Mean IQ value of the schoolchildren in Panshan was lower than that of Huanghua and higher than that of Zhangwu but, again, the differences were not significant., Conclusions: The increase of iodine intake may increase the risk for schoolchildren of subclinical hypothyroidism. In the area of iodine excess, most of the subclinical hypothyroidism cases are not of autoimmune origin. No obvious effect of excess iodine was found on mental development of schoolchildren.

Background: This study was designed to obtain a recombinant retroviral vector containing the human hepatocellular carcinoma-related gene ANGPTL4 (angiopoietin-like 4) cDNA and to evaluate the anti-tumor effect of recombinant retroviral vector-mediated human ANGPTL4 gene transfection., Methods: ANGPTL4 cDNA was cloned in vitro from normal human liver cells HL-7702 by using RT-PCR, and then subcloned into the plasmid vector pMSCV and sequenced. The retroviral plasmid vectors pMSCV-ANGPTL4, pVSV, and pGAG-POL were co-transfected into the packaging cell line 293 EBNA under mediation of lipofectamine. A high-titer retrovirus was obtained as a result, and HepG2 cells were infected with this retrovirus in vitro. Flow cytometry and fluorescence microscopy were used to detect expression of green fluorescence protein (GFP). The expression of ANGPTL4 mRNA in HepG2-ANGPTL4 cells was investigated using RT-PCR. The formation of tumors in nude mice and MTT assays were used to detect the growth of HepG2-ANGPTL4 cells in vivo and in vitro, respectively., Results: The cDNA sequence of the cloned ANGPTL4 gene was consistent with the recently reported sequence. Thus, the recombinant retroviral vector pMSCV-ANGPTL4 was constructed successfully. The titer of the packaged recombinant retrovirus was 1.4 x 10(6) infective viral grains/ml, and the rate of HepG2-ANGPTL4 cells expressing GFP was 68.45%, with an average intensity of fluorescence 31.67 times greater in HepG2-ANGPTL4 cells than in HepG2 cells. The expression of ANGPTL4 mRNA in HepG2-ANGPTL4 cells was higher than in HepG2-pMSCV cells (154% higher) or HepG2 cells (161% higher). The proliferation rate of HepG2-ANGPTL4 cells in vitro was obviously lower than those of HepG2-pMSCV cells and HepG2 cells (P <0.01). The mean volume and weight of tumors seeded from HepG2-ANGPTL4 cells were obviously lower than the mean volume or weight of tumors seeded from HepG2 cells and HepG2-pMSCV cells (P <0.01)., Conclusion: A stable ANGPTL4-transfected human liver cancer cell line HepG2-ANGPTL4 has been created. The transfer of the human ANGPTL4 gene mediated by a retroviral vector is a possibly effective approach for liver cancer therapy.

Background: An increasing incidence of Crohn's disease has been found in China in recent years. Our study has been focused on evaluating the diversity of the clinical manifestations of Crohn's disease in order to improve early diagnostic accuracy and therapeutic efficacy., Methods: Thirty patients with active Crohn's disease were enrolled and their clinical data, including diagnostic and therapeutic results, were analyzed. Endoscopy combined with histological examination of biopsy specimens provided characteristic features of the disease. Transabdominal bowel sonography (TABS) was used for detecting intestinal complications. Nutritional supportive therapy was given to 20 subjects with active cases of the disease., Results: Most patients were young adults with a higher proportion of females to males (ratio: 1.14:1). The disease affects any segment or a combination of segments along with the alimentary tract (from the mouth to the anus). In this study, the colon and small bowel were the major sites involved. Recurrent episodes of abdominal pain in the right lower quadrant and watery diarrhea were the most common symptoms. Granulomas were identifiable in nearly one-third (30.8%) of all biopsy specimens. In moderate cases of the disease, remission was achieved more quickly through the use of oral prednisone therapy than with SASP or 5-ASA. Beneficial effects on the host's nutritional status were observed. Immunosuppressives were used on an individual basis and showed variable therapeutic effects. Sixteen patients had surgery due to intestinal obstruction or failure to respond to drug therapies. Rapid improvement after surgery was reported., Conclusion: Endoscopy (with biopsy) and TABS were both crucial procedures for diagnosis. SASP (or 5-ASA) and prednisone were effective as inductive therapies. Azathioprine has demonstrable benefits after induction therapy with prednisone. Surgery, as an alternative treatment, provided another effective choice in selected patients.