[Analysis of curative effects of chemoembolization with drug-loaded microspheres of different particle sizes for the treatment of hepatocellular carcinoma].

Objective: To compare and analyze the clinical curative effect and safety of chemoembolization with drug-loaded microspheres of different particle sizes (D-TACE) for the treatment of hepatocellular carcinoma. Methods: Clinical data of 281 cases with hepatocellular carcinoma treated with drug-loaded microspheres-transarterial chemoembolization (TACE) were retrospectively analyzed. According to the different particle sizes of drug-loaded microspheres, they were divided into 100~300 µm (small particle size) and 300~500 µm (large particle size) group. Tumor response rate and complication conditions at 1, 3, and 6 months after chemoembolization were compared. The overall survival time of the two groups were analyzed. Quantitative data conformed to normal distribution and homogeneity of variance were compared using t-test, while other with Wilcoxon signed rank-sum test. Qualitative data were compared using χ2 test. Kaplan-Meier method was used for survival analysis, and the differences in survival were analyzed using Log-rank test. P＜0.05 was considered as statistically significant. Survival curves and histograms were drawn using GraphPad Prism9.1 software. Results: The complete remission rates at 1, 3 and 6 months after surgery in the small and large particle size groups were 31.25%, 30.15%, and 42.45% and 18.25%, 15.79% and 24.74%, respectively, and the differences were statistically significant between groups (P1 month=0.012, P3 month=0.009, P6 month=0.008, P＜0.05). The objective remission rates at 1, 3 and 6 months after surgery in the small and large particle size groups were 88.19%, 76.99%, and 70.75% and 81.02%, 72.81% and 53.60%, respectively. Six months after surgery, the small particle size group (objective response rate = 70.75%) was significantly higher than the large particle size group (objective response rate=53.6%, P=0.012). The disease control rates of the small particle size group were 95.14%, 83.33%, and 74.53%, while large particle size group were 91.24%, 81.58%, and 64.95%, respectively, with no statistically significant difference between the two groups. However, the incidence of postoperative biliary tumors (6.20%) was significantly higher in the small-size than large-size group (0.70%), and the difference was statistically significant (P＜0.05, P=0.03). There were no statistically significant differences between other adverse events such as post-embolization syndrome, liver abscess, and myelosuppression. The median survival time of the small and large particle size groups was 31.8 months and 20.5 months, respectively, but the difference was not statistically significant (P=0.182). Conclusions: In the treatment of hepatocellular carcinoma with D-TACE, the short-term curative effect of the small particle size group was better than large particle size group, but the incidence of biliary tumors was high, and D-TACE of different particle sizes had no significant effect on long-term survival.

Further evaluation of the safety and protective efficacy of live attenuated hepatitis A vaccine (H2-strain) in humans.

A study on the possibility of transmission of live hepatitis A vaccine (H2-strain) from vaccinees to nonvaccinees was conducted. As a result, no seroconversion was found among 87 seronegative nonvaccinees, who had a close contact with their 141 subcutaneously vaccinated classmates nor was it found among 101 seronegative children administered the vaccine orally. The above fundings suggest that by losing the ability to be transmitted orally the vaccine virus may result in a decreasing possibility of dissemination among contacts. A 4-year study on the protective efficacy of the H2-strain vaccine was done at 11 primary schools starting at 1991 in Shaoxing County. Since then, there has been no hepatitis A reported among 18102 cumulative person-years in the vaccination group, while 495 cases occurred among 242168 cumulative person-years in the control groups. A large scale vaccination with a cumulative vaccination coverage of 89.45% was carried out in Jiaojiang City among children 1-15 years old. Hepatitis A in this age group in the city, which had 12-87 cases per annum with an average of 32 for 8 years before vaccination, decreased drastically to 0-1 cases after vaccination. The protective efficacy of H2-strain vaccine proved to be satisfactory.

Primary study of attenuated live hepatitis A vaccine (H2 strain) in humans.

Strain H2, an attenuated live hepatitis A virus (HAV), was derived from the fecal specimen of a patient with hepatitis A in Hangzhou, China. After isolation and passage in a culture of newborn monkey kidney cells, adaptation to grow in human lung diploid cells (KMB17), and serial passage at a low temperature (32 degrees C) in KMB17 cells, this strain became the master seed virus for H2-strain vaccine. Twelve human volunteers received the experimental vaccine subcutaneously and were closely observed for 20 w. None of the subjects developed any local or systemic reactions, and there were no elevations of serum glutamic-pyruvic transaminase, type 5 isoenzyme of lactate dehydrogenase, or isocitrate dehydrogenase. Seroconversion occurred in all subjects at a mean time of 3 w after inoculation. ELISA competitive test for titer of antibody to HAV showed values ranging from 1:2 to 1:8 with a geometric mean titer of 1:3.48 at 20 w after inoculation. No marked decrease in titer of HAV antibody was found in the subjects tested at 1 y. These antibodies were proved to be neutralizing antibodies.

Studies in monkeys of attenuated hepatitis A variants.

Three HAV variants, H2M20(35 degrees C), H2M20(35 degrees C) and H2M20K5(32 degrees C), were developed by passage in different tissue culture cells and at different temperatures. Virulence for monkeys was assessed by inoculating each of the variants into four monkeys. Weekly bleeding through 16 weeks post-inoculation was assayed for anti-HAV titers and SGPT as well as LDH5 activities. And in some monkeys liver biopsies were also studied. Seroconversion was induced in all of the inoculated monkeys. The anti-HAV titers tested at 16 weeks post-inoculation were: 40-640 with H2M20(35 degrees C), 40-160 with H2M20(32 degrees C) and 20-40 with H2M20K5(32 degrees C). These variants showed different levels of virulence/attenuation for monkeys. Variant H2M20(35 degrees C) showed no evidence of attenuation, variant H2M20(32 degrees C) retained slight virulence and variant H2M20K5(32 degrees C) showed no evidence of virulence for monkeys. Criteria are proposed for assay of HAV virulence tested in monkeys.

Studies on the transmission of human hepatitis A virus to stump-tailed monkey.

The newly-caught stump-tailed monkeys (Macaca speciosa) with negative antibody to hepatitis A were inoculated with human hepatitis A virus. The following findings were observed in the monkeys after inoculation: (i) the elevation of activities of the serum glutamic-pyruvic transaminase, lactate dehydrogenase and its isoenzyme (LDH5), (ii) the seroconversion of antibody to hepatitis A virus. (iii) the shedding of hepatitis A antigen in feces. These findings show that the stump-tailed monkey (Macaca speciosa) is susceptible to infection of human hepatitis A virus. The virus recovered from the feces of the infected monkey, named as Hang-zhou A-1A strain of hepatitis A virus, has experienced two generations of successful transmission in monkeys.

Susceptibility of monkeys to human hepatitis A virus.

A stump-tailed monkey, newly caught and without antibody to hepatitis B virus (HAV), was successfully infected with human HAV. The following alterations were observed in the monkey's functions: (1) elevation in activities of serum glutamic pyruvic transaminase, lactate dehydrogenase, and its type 5 isoenzyme (electrophoretically the fastest moving); (2) development of antibody to HAV; and (3) shedding of HAV antigen in feces. The virus isolated from the monkey, designated the Hangzhou A-1A strain of HAV, was serially transmitted to two other stump-tailed monkeys. Thus, the stump-tailed monkey (Macaca speciosa) is susceptible to infection with human HAV.

Patterns of shedding of hepatitis A virus antigen in feces and of antibody responses in patients with naturally acquired type A hepatitis.

Serial stools and sera from 13 patients with hepatitis A were collected during an epidemic in 1978 in a rural village near Hangzhou, China, and were studied to determine the patterns of shedding of hepatitis A antigen (HAAg) and of antibody response in some cases. Of 44 stool specimens, 31 were HAAg-positive by a radioimmunoprecipitation-polyethylene glycol assay. The highest percentage of HAAg positivity was in stools collected one week before and one week after the peak elevation of serum glutamic pyruvic transaminase (SGPT) levels, and peak HAAg shedding in each patient usually occurred in the early stools. Fecal shedding of HAAg was detected as early as day 19 before peak elevation in SGPT level and as late as day 11 afterward and continued for at least 25 days. The pattern of HAAg shedding in feces and of complement-fixation and immune adherence antibody response in relation to the change in SGPT activity and jaundice in four patients with hepatitis A was demonstrated.