Prediction value of radiosensitivity of hepatocarcinoma cells for apoptosis and micronucleus assay

AIM： To investigate the prediction value of radiosensitivity of hepatocarcinoma cells for apoptosis and rnicronucleus assay. METHODS： Clonogenic assay, flow cytometry, and CB micronuclei assay were used to survey the cell survival rate, radiation-induced apoptosis and rnicronucleus frequency of hepatocarcinorna cell lines SMMC-7721, HL-7702, and HepG2 after being irradiated by X-ray at the dosage ranging 0-8 Gy. RESULTS： After irradiation, there was a dose-effect relationship between rnicronucleus frequency and radiation dosage among the three cell lines （P〈0.05）. A positive relationship was observed between apoptosis and radiation dosage among the three cell lines. The HepG2 cells had a significant correlation （P〈0.05） but apoptosis incidence had a negative relationship with rnicronucleus frequency. There was a positive relationship between apoptosis and radiation dosage and the correlation between 5MMC-7721 and HL-7702 cell lines had a significant difference （P〈0.01）. After irradiation, a negative relationship between cell survival rate and radiation dosages was found among the three cell lines （P〈0.01）. There was a positive relationship between cell survival rate and rnicronucleus frequency （P〈0.01）. No correlation was observed between apoptosis and cell survival rate. CONCLUSION： The radiosensiUvity of hepatocarcinoma cells can be reflected by apoptosis and rnicronuclei. Detection of apoptosis and rnicronuclei could enhance the accuracy for predicting radiosensitivity.

Cell cycle and radiosensitivity of progeny of irradiated primary cultured human hepatocarcinoma cells

AIM： To evaluate the change of growth characteristics and radiosensitivity of irradiated primary cultured human hepatocarcinoma cells. METHODS： All tumor tissue samples were obtained from 39 hepatocarcinoma patients with a mean age of 49.6 years （range 22-76 years）. We divided the samples into irradiated group and non-irradiated group and measured their plating efficiency （PE）, population doubling time （PDT）, radiosensitivity index SF2 and cell RESULTS： The PDT of primary culture of hepatocardnoma cells was 91.0±6.6 h, PE was 12.0±1.4%, SF2 was 0.41±0.05%. The PDT of their inadiated progeny was 124.8±5.8 h, PE was 5.0±0.7%, SF2 was 0.65±0.09%. The pdmary cultured human hepatocarcinoma cells showed significant S reduction and G^2 arrest in a dose-dependent manner. The progeny of irradiated primary cultured hepatocarcinoma cells grew more slowly and its radiosensitivity increased. CONCLUSION： The progeny of irradiated primary cultured human hepatocarcinoma cells grows more slowly and its radiosensitivity increases.

Cell survival curve for primary hepatic carcinoma cells and relationship between SF2 of hepatic carcinoma cells and radiosensitivity

AIM： To establish the cell survival curve for primary hepatic carcinoma cells and to study the relationship between SF2 of primary hepatic carcinoma cells and radiosensitivity. METHODS： Hepatic carcinoma cells were cultured in vitro using 39 samples of hepatic carcinoma at stages Ⅱ-Ⅳ. Twenty-nine samples were cultured successfully in the fifth generation cells. After these cells were radiated with different dosages, the cell survival ratio and SF2 were calculated by clonogenic assay and SF2 model respectively. The relationship between SF2 and the clinical pathological feature was analyzed. RESULTS： Twenty-nine of thirty-nine samples were successfully cultured. After X-ray radiation of the fifth generation cells with 0, 2, 4, 6, 8 Gy, the cell survival rate was410, 36.5%, 31.0%, 26.8%, and 19%, respectively. There was a negative correlation between cell survival and irradiation dosage （r = -0.973, P〈0.05）. SF2 ranged 0.28-0.78 and correlated with the clinical stage and pathological grade of hepatic carcinoma （P〈0.05）. There was a positive correlation between SF2 and D0.5 （r = 0.773, P〈0.05）. CONCLUSION： SF2 correlates with the clinical stage and pathological grade of hepatic carcinoma and is a marker for predicting the radiosensitivity of hepatic carcinomas.

Improving native human sperm freezing protection by using a modified vitrification method

Slow freezing is the most commonly used technique for the cryopreservation of spermatozoa in clinical practice.However,it has been shown to have a negative impact on sperm function and structure.Vitrification as a successful alternative method has been proved to have better protective effects on human embryos,but vitrification of spermatozoa is still subject to low recovery rates.In this study,a modified vitrification method for native spermatozoa was developed.A total of 28 semen samples were included;each sample was divided into three equal parts and assigned to fresh,slow freezing,and vitrification groups.Sperm vitality,motility,morphology,DNA integrity,and acrosome reaction were assessed for each of the groups.The results showed that vitrification achieves better results for several sperm protection parameters than slow freezing;vitrification achieves a higher recovery rate(P<0.05),motility(P<0.05),morphology(P<0.05),and curve line velocity(P<0.05)than slow freezing.Furthermore,DNA fragmentation was decreased(P<0.05)and better acrosome protection(P<0.05)was exhibited in the spermatozoa after vitrification.Principal component analysis of all sperm parameters revealed that the vitrification cluster was closer to the fresh cluster,indicating that spermatozoa are better preserved through vitrification.In conclusion,while both slow freezing and vitrification have negative effects on sperm function and structure,the vitrification protocol described here had a relatively better recovery rate(65.8%)and showed improved preservation of several sperm quality parameters compared with slow freezing.

On the selection of solutions for mutation in differential evolution

Differential evolution （DE） is a kind of evolutionary algorithms, which is suitable for solving complex optimization problems. Mutation is a crucial step in DE that generates new solutions from old ones. It was argued and has been commonly adopted in DE that the solutions selected for mutation should have mutually different indices. This restrained condition, however, has not been verified either theoretically or empirically yet. In this paper, we empirically investigate the selection of solutions for mutation in DE. From the observation of the extensive experiments, we suggest that the restrained condition could be relaxed for some classical DE versions as well as some advanced DE variants. Moreover, relaxing the restrained condition may also be useful in designing better future DE algorithms.