[Sample size for the estimation of F-wave parameters in healthy volunteers and amyotrophic lateral sclerosis patients]

Objective: The study aimed to investigate whether sample sizes of F-wave study differed according to different nerves, different F-wave parameters, and amyotrophic lateral sclerosis(ALS) patients or healthy subjects. Methods: The F-waves in the median, ulnar, tibial, and deep peroneal nerves of 55 amyotrophic lateral sclerosis (ALS) patients and 52 healthy subjects were studied to assess the effect of sample size on the accuracy of measurements of the following F-wave parameters: F-wave minimum latency, maximum latency, mean latency, F-wave persistence, F-wave chronodispersion, mean and maximum F-wave amplitude. A hundred stimuli were used in F-wave study. The values obtained from 100 stimuli were considered "true" values and were compared with the corresponding values from smaller samples of 20, 40, 60 and 80 stimuli. F-wave parameters obtained from different sample sizes were compared between the ALS patients and the normal controls. Results: Significant differences were not detected with samples above 60 stimuli for chronodispersion in all four nerves in normal participants. Significant differences were not detected with samples above 40 stimuli for maximum F-wave amplitude in median, ulnar and tibial nerves in normal participants. When comparing ALS patients and normal controls, significant differences were detected in the maximum (median nerve, Z=-3.560, P<0.01; ulnar nerve, t=5.019, P<0.01; tibial nerve, Z=-2.475, P<0.05; peroneal nerve, Z=-2.088, P<0.05)and mean F-wave latency (median nerve, Z=-3.243, P<0.01; ulnar nerve, t=3.876, P<0.01; tibial nerve, Z=-2.206, P<0.05; peroneal nerve, Z=-2.205, P<0.05)in all four nerves, F-wave chronodispersion (Z=-3.152, P<0.01)in the ulnar nerve, F-wave persistence in the median (Z=6.139, P<0.01)and ulnar nerves(Z=5.350, P<0.01), mean F-wave amplitude in the tibial nerve(t=2.981, P<0.01), maximum F-wave amplitude in the ulnar (Z=-2.134, P<0.05)and tibial nerves (t=2.746, P<0.01)with 20 stimuli; for chronodispersion in tibial nerve (t=2.551, P<0.05)100 stimuli, for chronodispersion in peroneal nerve (Z=-2.086, P<0.05)80 stimuli, for F-wave persistence in tibial nerve (Z=2.119, P<0.05) 60 stimuli, for mean F-wave amplitude in ulnar (Z=-2.552, P<0.05)and peroneal nerve (Z=-2.228, P<0.05)40 stimuli, for maximum F-wave amplitude in peroneal nerve (t=2.693, P<0.01)60 stimuli were necessary to detect differences. Conclusions: Sample sizes of F-wave study differed according to different nerves, different F-wave parameters , and ALS patients or healthy subjects.

Relationship between the characteristics of immunopathological expression of hepatitis C virus antigen and hepatocytic injury

Biopsied liver tissues from 352 cases were tested for hepatitis C virus (HCVAg) with improved PAP immunohistologic chemical method. Furthermore, corresponding seroantibody to hepatitis C virus was also tested. The total HCVAg positive rate was 9.1%. The HCVAg positive rate in chronic persistent hepatitis (CPH) was 5%. The HCVAg positive rate in chronic active hepatitis (CAH) was 11.2%. The HCVAg positive rate raised gradually along with the severity of hepatocytic injury. HCVAg may be seen in necrotic liver cells exfoliating into the liver sinus, indicating a close relationship between HCVAg and hepatocytic injury. Expression of HCVAg was mostly of the nucleus type in CPH cases and was mostly of the plasma type in CAH cases. The periphery of nucleus type-expressed positive cells generally had no marked inflammatory cell infiltration. The periphery of plasma type-expressed positive cells had a certain amount of inflammatory cell infiltration. Along with the severity of hepatocytic injury, HCVAg expressed itself in a positive correlation according to the nucleus and plasma types. The HCVAg positive cells were located mostly in the lobular peripheral band and rarely located in the venoperipheral band. It was possible that this had some relation with the lobular microcirculation of blood and blood supply. In this study, there was no obvious correlation between the HCVAg positive rate in hepatic tissues and the anti-HCV positive rate in sera. Neither the patients with HCVAg positive liver tissues nor the patients with seropositive anti-HCV had any history of blood transfusion and the use of blood products.(ABSTRACT TRUNCATED AT 250 WORDS)