Biomedical subjects
Publications and source records attributed to Bin Cheng.
1-D ZnO nanorods with different aspect ratios were synthesized by a one-step, hydrothermal method. The ZnO nanorods grow along the [0001] direction to form single crystals. The experimental results reveal that the growth of polar inorganic crystals is sensitive to the reaction solvents.
Accumulation of genetic alterations in hepatocarcinogenesis is closely associated with chronic inflammatory liver disease. 8-oxo-2'-deoxyguanosine (8-oxo-dG), the major promutagenic DNA adduct caused by reactive oxygen species (ROS), leads to G:C --> T:A transversions. These lesions can be enzymatically repaired mainly by human MutT homolog 1 (hMTH1), human 8-oxo-guanine DNA glycosylase (hOGG1) and human MutY homolog (hMYH). The aim of this study was to evaluate the extent of oxidative damage and its dependence on the cellular antioxidative capacity and the expression of specific DNA repair enzymes in tumor (tu) and corresponding adjacent nontumor (ntu) liver tissue of 23 patients with histologically confirmed hepatocellular carcinoma. 8-oxo-dG levels, as detected by high-pressure liquid chromatography with electrochemical detection, were significantly (P =.003) elevated in ntu tissue (median, 129 fmol/microg DNA) as compared to tu tissue (median, 52 fmol/microg DNA), and were closely associated with inflammatory infiltration. In ntu tissue, the hepatic iron concentration and malondialdehyde levels were significantly (P =.001) higher as compared to tu tissue. Glutathione content, glutathione peroxidase activity and manganese superoxide dismutase messenger RNA (mRNA) expression did not show statistical differences between ntu and tu tissue. Real-time reverse transcription polymerase chain reaction revealed in tu tissue significantly (P =.014) higher hMTH1 mRNA expression compared to ntu tissue. In contrast, hMYH mRNA expression was significantly (P <.05) higher in ntu tissue. No difference in hOGG1 mRNA expression was seen between tu and ntu. In conclusion, these data suggest that ROS generated by chronic inflammation contribute to human hepatocarcinogenesis. The role of DNA repair enzymes appears to be of reactive rather than causative manner.
OBJECTIVE: The purpose of this study was to identify and measure apoptotic cells in whole saliva of patients with oral premalignant and malignant lesions and explore its utility as a prognostic indicator. STUDY DESIGN: A fluorescent TUNEL technique (APO-BrdU TUNEL) modified by our lab was applied to unstimulated whole saliva from 8 healthy volunteers, 16 patients with oral leukoplakia and/or lichen planus, 10 untreated and 5 treated cases with oral malignant lesion. RESULTS: The apoptotic cells in whole saliva were detected in 4 groups of study subjects. The apoptotic cells demonstrated morphology similar to normal exfoliated epithelial cells of oral mucosa. The fraction of apoptotic cell in treated malignant patients (18.18+/-12.65) was significantly higher than that in healthy volunteers (6.99+/-6.52), premalignant patients (4.43+/-5.52), and untreated malignant patients (3.40+/-5.14) (P<.05). CONCLUSION: Detection of apoptotic epithelial cells in whole saliva appears to have some clinical potential in monitoring reaction to chemoradiotherapy and may reveal some insight into the mechanism of oral carcinogenesis.
BACKGROUND & OBJECTIVE: Previous studies have revealed the close relationship between Fas/FasL pathway and carcinogenesis of oral squamous cell carcinoma (OSCC). This study was designed to explore the potential of cdc25A-Fas chimeric expression vector in inducing apoptosis of human OSCC cell line Tca8113. METHODS: The 2 chimeric expression vector pAdTrack-CMV-cdc25A-Fas (pCCF), and pAdTrack-cdc25A-Fas (pCF) were constructed by gene engineering, pCCF, pCF, and the control plasmid pAdTrack-CMV were transfected into Tca8113 cells by liposome, respectively. The transfection efficiency was presented by the expression of the report gene, green fluorescence protein (GFP). The mRNA and protein levels of Fas were determined by Northern blot analysis, reverse transcription-polymerase chain reaction (RT-PCR), Western blot analysis, and immunohistochemistry methods. The apoptosis of transfected Tca8113 cells was analyzed by techniques of DNA agarose gel electrophoresis, TUNEL, Annexin V label, and flow cytometry (FCM). RESULTS: (1) The chimeric expression vectors pCCF, and pCF were successfully transfected into Tca8113 cells and the maximum transfection (15%) was observed at the 5th-7th day after transfection. (2) Up-regulation of Fas expression was detected at the 3rd day after transfection in pCCF, and pCF transfection groups. At 3rd, 5th, and 7th day after transfection, Fas protein was found to express on membrane and in plasma of transfected Tca8113 cells with distinct morphology of partial apoptosis. (3) From 2.5 days after transfection, early apoptosis had been observed in pCCF, and pCF transfection groups. At 3rd day, the increased apoptosis index (AI,=25%) of pCCF, and pCF transfection groups was significant higher than that of control group (P< 0.05), whereas there was no significant difference in AI between pCCF transfection group and pCF transfection group (P >0.05). (4) FCM analysis showed that the peak of GFP-expression cells was identical to that of the apoptotic cells. CONCLUSION: The cdc25A-Fas chimeric expression vector was able to initiate the apoptosis of Tca8113 cells by up-regulating Fas expression. This result indicated that the 27 bp cdc25A fragment can be designed as a cis-regulatory element to modulate the effects of C-Myc/Max in cellular proliferation and apoptosis.
AIM: To study the chemical constituents of Marsdenia tenacissima (Roxb.) Wight et Arn. METHODS: To separate compounds with various chromatography technology and to elucidate their structures by chemical and spectral analysis. RESULTS: Two compounds were isolated from Marsdenia tenacissima and their stuctures were determined as tenacissosides J (I) and tenacissosides K (II). CONCLUSION: Compounds I and II are new C21 steroidal glycosides.
OBJECTIVE: To investigate the relationship of Fas mRNA and protein expression and apoptosis in human oral squamous cell carcinoma. METHODS: Northern blot and flow cytometry (TUNEL method) were used to detect the expression of Fas mRNA and Fas protein, cell cycle and apoptotic level in oral squamous cell carcinoma. The relationship between Fas gene expression and OSCC apoptosis was analyzed statistically. RESULTS: Fas mRNA and protein could be detected in all five normal oral mucosa specimens. There was positive correlation between expression of Fas mRNA/protein and cell differentiation as well as apoptosis in OSCC (P < 0.005). CONCLUSION: The expression of Fas gene was highly correlated with the differentiation and apoptosis in OSCC.
Single-crystal selenium nanowires were successfully synthesized for the first time by a convenient solution-mediated transformation of polycrystalline powder, and characterized by SEM, XRD, TEM and HRTEM.
OBJECTIVE: The aim of the study was to evaluate the clinical efficacy of Oratest in detecting oral mucosal lesions. METHODS: Sixty patients with oral mucosal lesions that were suspected as carcinoma or premalignant lesions were divided into two groups randomly. The lesions were stained with Oratest by topical application in one group and rinse application in another group. Staining results were recorded and compared with the pathological diagnosis. RESULTS: The sensitivity of Oratest stain to oral carcinoma and dysplasia were 93.9% and 42.9%, respectively. The difference between rinse application and local application showed no significance(P > 0.01). CONCLUSION: Oratest can be used as a method of diagnosing squamous cell carcinoma of oral mucosa, but its reliability in screening oral pre-malignant lesions is still uncertain.
OBJECTIVE: To investigate the relationship of apoptosis and expression of Fas gene in oral squamous cell carcinoma. METHODS: Plasmid including Fas gene was transfected into Tca8113 cell by lipofectamine kit. The expression of Fas mRNA in transfected and non-transfected cell was detected by RT-PCR. The expression of Fas protein and apoptosis index(AI) was assessed by flow cytometry(FCM). RESULTS: No variation of positive expression rate of Fas protein was found in Fas-transfected and non-transfected Tca8113 (P > 0.05), but the expression of Fas mRNA, intensity of Fas protein and apoptosis index were significantly increased respectively from 0.201 +/- 0.015, 31.02 +/- 4.63, 0.88% +/- 0.16% to 0.399 +/- 0.073, 54.32 +/- 6.38 and 10.21% +/- 1.46%(P < 0.01). CONCLUSION: Apoptosis in tongue squamous cell carcinoma was not directly associated with the positive expression rate but intensity of Fas protein. A liminal value might exist before apoptosis in Tca8113 cell could be activated.
To elucidate role of the three enzymes in hepatocarcinogenesis, hMTH1, hOGG1 and hMYH, mRNA expression were examined by using RT/semi-quantitative real-time PCR and 8-O-HdG levels was studied by HPLC/ECD in HCC and non-tumorous liver tissue of 21 patients with hepatocellular carcinoma (HCC). It was found that the 8-OHdG level in non-tumourous liver tissue was significantly higher than in HCC tissue (P = 0.006), and this was correlated with the degree of inflammation. The hMTH1 expression in HCC tissue was significantly higher than in non-tumorous liver tissue (P = 0.014). Inversely, The hMYH alpha expression was significantly increased (P = 0.039) in non-tumorous liver tissue. No difference was seen in hOGG1 expression in non-tumorous liver and HCC tissue. A significant linear correlation between hMTH1 and hOGG1 expression was found both in HCC tissue (r = 0.809, P < 0.001) and in non-tumorous liver tissue (r = 0.883, P < 0.001). Our findings suggested a reactive rather than pathogenic role of the DNA repair enzymes in the hepatocarcinogenesis.
For locally acting drug products such as nasal aerosols and nasal sprays, therapeutic equivalence between two drug products may be established by in vitro bioequivalence studies based on measurements intended to reflect the rate and extent to which the active ingredient becomes available at the site of action. For cascade impaction or multistage liquid impinger for particle size distribution, profile analysis is required. However, we find that the analysis procedure described in the 1999 FDA guidance lacks statistical justification. In this article, we explain why FDA's approach is incorrect and propose a correct statistical method for profile analysis using the basic ideas in the FDA guidance.
PURPOSE: To assess the concentrations of vascular endothelial growth factor (VEGF) in aqueous humor in eyes with and without glaucoma. METHODS: Concentrations of VEGF were measured using a sandwich ELISA kit in aqueous humor aspirates taken during anterior segment surgery from 87 patients, of whom 54 had glaucoma (27 primary open-angle glaucoma, 8 angle-closure glaucoma, 16 exfoliative glaucoma) and 33 had cataract only. RESULTS: Vascular endothelial growth factor was detected in all samples. The concentration in eyes with cataract only without glaucoma was 102.4 +/- 29.7 pg/mL (mean +/- SD), which was significantly lower than that from eyes with glaucoma (146.7 +/- 51.8 pg/mL). There were no significant differences between primary open-angle glaucoma (140.4 +/- 51.0 pg/mL), angle-closure glaucoma (142.8 +/- 40.2 pg/mL), and exfoliative glaucoma (158.6 +/- 58.9 pg/mL). An unusually high VEGF concentration was detected in one eye with neovascular glaucoma (759 pg/mL) and two eyes with uveitic glaucoma (322 pg/mL). No effect of age, gender, or previous history of medical, laser, or surgical treatment of the aqueous humor VEGF concentration could be detected ( > 0.05). Aqueous humor and plasma VEGF concentrations were measured and compared in 46 patients. The aqueous humor VEGF concentration (144.2 +/- 107.9 pg/mL) was significantly higher ( < 0.01) than the plasma concentration (79.2 +/- 46.1 pg/mL). No significant correlation was found between aqueous humor and plasma VEGF concentrations. CONCLUSION: Aqueous VEGF concentration is increased in eyes with glaucoma.
BACKGROUND AND OBJECTIVE: The process of carcinogenesis is not only correlated to the abnormality of cell proliferation but also to the change of normal cell apoptosis. The aim of this study was to investigate the mechanism of apoptosis induced by c-myc(cellular avian myelocytoma virus) gene in oral squamous cell carcinoma cell line Tca8113. METHODS: Plasmid including c-myc gene was transfected into Tca8113 cell by using lipofectamine kit. The cells were selected by G418. The expression of fas(fatty acid synthase) gene in transfected and non-transfected Tca8113 cell was detected by RT-PCR. Apoptosis of Tca8113 cell was determined by TUNEL. RESULTS: Up-regulation of fas expression was found in c-myc transfected Tca8113 cell. The increased apoptosis index (AI) could only be found under the condition of low serum concentration. CONCLUSIONS: c-myc could mediate apoptosis of oral squamous cell carcinoma in certain condition. This might be related with the up-regulation of fas expression.