AIM: To construct a high-level expression system of recombinant human neuronal nitric oxide synthase (hnNOS) full-length enzyme in Escherichia coli. METHODS: The coding sequence of hnNOS full-length was firstly amplified by PCR, and then ligated into the expression vector pCWori+. The recombinant plasmid was transformed into Escherichia coli BL21 for high-level expression. After having been checked with Western blot, the enzyme was used for large-scale culture and purification. Finally, the property of the enzyme was determined by spectrophotometric method. RESULTS: The constructed expression system could give a yielding of 3 mg/L initial culture. CONCLUSION: The expression system constructed is fully sufficient to express the active human neuronal nitric oxide synthase.

AIM: To examine the microsatellite instability (MSI) and loss of heterozygosity (LOH) in head and neck squamous cell carcinomas (HNSCC). METHODS: 36 cases of HNSCC were analyzed with 15 microsatellite markers from chromosome 3,5,6,8,9,13,17 and 18. RESULTS: Among the 36 cases of HNSCC, 27.8%(10/36)of samples showed MSI in one to eight microsatellite markers. High frequent MSI occurred at D17S520(22.9%), D6S105(16 7%)and D8S264(13 9%). LOH was detected on the site of 9p21-p22 and 3p14. No correlations were found between allelic instability and grade or stage of the tumor. CONCLUSION: Our data suggest that MSI is a common genetic change in HNSCC. Tumor suppressor genes related to HNSCC may harbor at chromosome 9p21-p22 and 3p14 regions. [

AIM: To assess the antiradiation effect of oligomeric procyanidins. METHODS: The hemolysis, malondialdehyde(MDA) levels of mouse liver homogenates and the broken degree of DNA single-strain after being irradiated by ultraviolet were examined. RESULTS: Oligomeric procyanidins significantly reduced the hemolysis of erythrocytes induced by ultraviolet irradiation, inhibited the increase in MDA levels of irradiated mouse liver homogenates ( P

AIM: To investigate the effect of tea polyphenols (TP) on alcohol-induced liver injury in mice.METHODS: 40% alcohol(0 5 mL) and TP (5 mg) were administered intragastrically, the liver MDA level and serum alanine transaminase (ALT) activity were determined. The effect of TP on MDA level in alcohol-treated liver in vitro was also examined.RESULTS: Pretreatment with TP significantly inhibited alcohol-induced liver MDA increase in mice in vivo and in vitro , the increase in serum ALT induced by alcohol was also reduced by pretreatment with TP (0 5 mg). TP at a dose of 5 mg, administered 1 h after alcohol treatment, also suppressed increase in liver MDA level stimulated by alcohol. CONCLUSION: These results demonstrated that TP has a protective effect on alcohol-induced liver injury in mice.

0.05), but in model rats it gradually increased at 2,4,6 and 8 weeks after endometriosis ( P