Objective To study the liver histological changes in chronic hepaitits B (CHB) patients with normal serum alanine aminotransferase (ALT) levels and the related factors. Methods Six hundred and thirty-two CHB patients with normal ALT levels had undergone ultrasound guided percutaneous liver biopsies. All specimen were examined by HE staining, collagen fiber Masson staining and immunohistochemical staining for hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg). The Knodell inflammation score and Ishak fibrosis score were both calculated and the relationship with age, serum levels of ALT and hepatitis B virus (HBV) DNA, hepatic expressions of HBsAg and HBcAg were analyzed. The means between two groups were compared by t test and those among groups were compared by one-factor analysis of variance and q test. Enumeration data were analyzed by x2 test. Results Among 632 CHB patients with normal ALT levels, 167 (26.4%) showed moderate necrotic inflammation in liver tissues and 26 (4.1%) showed severe necrotic inflammation; 217 (34. 3 % ) showed moderate fibrosis and 52 (8. 2 % ) showed severe fibrosis (cirrhosis). The Knodell inflammation score and Ishak fibrosis score in high ALT group were higher than low ALT group, those in female high ALT group were higher than male high ALT group and those in patients ＞ 40 years old were higher than ≤20 years old (q= 19.63, P＜0. 05). The liver injuries in patients with active HBV replication were more severe than those with undetectable HBV DNA levels (Knodell score, q=3.87, 2.87, 6.34; Ishak score, q=2.64,2. 64,5.54, all P＜0. 05),while there was no significant difference between patients with high levels and low levels of HBV DNA (F= 1.35, P＞0. 05). There was no significant difference between expressions of HBsAg (F= 1.65,0. 73,respectively; both P＞0. 05) and HBcAg in liver tissues and Knodell inflammation score and Ishak fibrosis score (F=0. 17, 1.29, respectively; both P＞0. 05). Conclusions Liver biopsies should be considered in CHB patients with normal ALT levels and detectable HBV DNA levels, especially those ＞ 40 years old and with ALT of (0.75-1.00) × upper limits of normal (ULN).

Objective:Labview and VC were used to design software based on the Active One biopotential measurement system to realize the visual evoked potential based brain-computer interface.Methods:The data acquisition software was designed by Labview,the human-interface,real time signal processing and dynamic link library software were designed by VC.Data transmission between Labview and VC was realized through the dynamic link library using shared memory technology.The multimedia timer,DirectDraw technology and parallel port data output were used to design the visual stimulation interface.The 5 points averaging filter combining with averaging method were used to detect the visual evoked potential and the correlation coefficient was computed for signal recognization.Results:The experiments showed that the visual stimulator can produce effective visual stimulation.The data transmission method using the dynamic link library can satisfy the requirement of the system.Conclusions:The real-time signal processing method can improve signal-noise ratio and realize detection and recognization of visual evoked potential.The system can determine which module the subject was fixating and the result was feedback to the subject in real time.