Glycophorin A mutation and relevant factors in medical radiation workers / 中华放射医学与防护杂志

Objective To explore the feasibility of using glycophorin A somatic mutation in peripheral erythrocytes,in order to evaluate the cancer risk of occupational medical exposure to ionizing radiation.Methods Totally 336 medical radiation workers were recruited as three groups (general radiation group,computer tomography group,intervention and radiation treatment group) and 112 healthy adults were selected as control by using stratified random cluster sampling method,where 176 medicalradiation workers and 58 health controls had a MN-heterozygous type.The erythrocytes were fixed and bound with fluorescent-labeled monoclonal antibody,and the glycophorin A somatic mutation frequency was assayed by a modified BR6-1W1 method using a FACScan flow cytometer.The individual susceptibility to radiation was investigated using micronuclei test and 3-Aminobenzamide index test.Results The GPA somatic mutation frequency of medical-radiation workers was significantly higher than that of healthy control ( t =2.29 - 11.48,P ＜ 0.05 ).In particular,the NO GPA aberration frequency of interventional radiology workers was much higher than that of the general medical diagnostic workers (t =2.01,P ＜ 0.05).In addition,the NO GPA variant frequency changed significantly with the years of radiation service,cumulative doses,and 3AB index.However,the NN GPA variant frequency was only associated with the years of radiation service,and no significant correlations were found between NN GPA variant frequency and cumulative dose of radiation exposure or 3AB index. Conclusions GPA mutation frequency,especially NO GPA mutation frequency could be used as a sensitive biomarker to predict the DNA damage and individual susceptibility for the population exposed to professional low-dose ionizing radiation.

Frequencies of Mutations at Glycophorin-A Locus of Erythrocytes in Patients with High Arsenic Coal Poisoning / 中华皮肤科杂志

Objectives To observe the frequencies of mutations at glycophorin A(GPA)of erythro-cytes in patients with high arsenic coal poisoning(HACP)in comparison with normal controls.Methods The peripheral erythrocytes were isolated and immunolabelled,and were detected by flow cytometry in40patients and18normal adults.Results The mutation frequencies(MF)were(21.23?13.97)?10 -6 for type NN,(33.13?25.72)?10 -6 for type NO,(110.90?63.58)?10 -6 for type MM,and(20.35?21.26)?10 -6 for type MO of erythrocytes in patients with HACP,which were significantly higher than those in normal controls.The mutation frequencies were(31.50?16.13)?10 -6 for type NN,(54.50?38.13)?10 -6 for type NO,(159.33?66.22)?10 -6 for type MM,and(45.16?12.69)?10 -6 for type MO of erythrocytes in tumor group of HACP patients,which were significantly higher than those of non-tumor group of the patients.Conclusions Arsenic poisoning may induce the mutation at the glycophorin-A locus of erythrocytes,sug-gesting that arsenic may be one of potential mutagens.GPA-MF may serve as a parameter for the detection of patients with HACP.

Detection of fetal erythroid cells from maternal blood using fluorescence in situ hybridization and liquid culture

Fetal nucleated erythrocytes circulating in maternal blood are a potential source of fetal DNA for noninvasive prenatal genetic diagnosis. However, the estimated ratio of fetal to maternal cells is extremely small. In order to enrich these cells, we performed direct culture using a two-phase liquid system. Mononuclear cells were obtained from maternal blood samples at 8-10(+3) weeks of gestation and cultured in the first phase. After 4-5 days, the nonadherent cells were harvested and recultured with erythropoietin in the second phase for another 3-5 days. We examined cellular morphology, and counted the number of benzidine- positive cells and the percentage of glycophorin A/CD71 positive erythroid cells. We also did Kleihauer-Betke stain for Hb F, polymerase chain reaction (PCR) for SRY/DYZ1, chromosome analysis, and fluorescence in situ hybridization (FISH). The number of total erythroid cells reached about 0.1x10(6)-1.0x10(6)/mL with a purity of 84.0-97.3%. Hb F stain showed total erythroid cells of approximately 0.4x10(4)-9.8x10(4)/mL. Male DNA was detected in one case by PCR. In this case, the XY karyotype was confirmed by FISH and amniocentesis. This approach provides enriched source of fetal cells for further prenatal genetic analysis without complicated separation or sorting procedures.

Assessment of the Glycophorin A Mutant Assay as a Biologic Marker for Low Dose Radiation Exposure / 예방의학회지

OBJECTIVES: To assess the availability of the glycophorin A (GPA) assay to detect the biological effect of ionizing radiation in workers exposed to low-doses of radiation. METHODS: Information on confounding factors, such as age and cigarette smoking was obtained on 144 nuclear power plant workers and 32 hospital workers, by a self-administered questionnaire. Information on physical exposure levels was obtained from the registries of radiation exposure monitoring and control at each facility. The GPA mutant assay was performed using the BR6 method with modification by using a FACScan flow cytometer. RESULTS: As confounders, age and cigarette smoking habits showed increasing trends with GPA variants, but these were of no statistical significance. Hospital workers showed a higher frequency of the GPA variant than nuclear power plant workers in terms of the NO variant. Significant dose-response relationships were obtained from in simple and multiple linear regression models. The slope of the regression equation for nuclear power plant workers was much smaller than that of hospital workers. These findings suggest that there may be apparent dose-rate effects. CONCLUSION: In population exposed to chronic low-dose radiation, the GPA assay has a potential to be used as an effective biologic marker for assessing the bone marrow cumulative exposure dose.

Cloning of glycophorin A cDNA and construction of its expression plasmid for yeast two hybrid system / 中国病理生理杂志

AIM: To obtain the glycopohorin A (GPA) cDNA and construct the target gene in yeast two-hybrid.METHODS: About 410 bp cDNA fragment was amplified from K562 cell by RT-PCR.After being sequenced, the GPA gene fragment was cloned into EcoR -Ⅰ- Pst Ⅰ site of pbridge to form BD ends in yeast two-hybrid system. The recombinant plasmid was transfered into yeast AH109, and the expression in the yeast was also examined. RESULTS: The amino acid sequence encoded by cloned cDNA was mostly the same as reported GPA, and about 1 mm white yeast clone grew in the selective medium after 3 d.CONCLUSION: pbridge-GPA has nontoxic to the yeast, which can serve as a target gene in yeast two-hybrid system.

THE RECEPTOR ROLE OF GLYCOPHORIN A DURING THE INVASION OF ERYTHROCYTES BY PLASMODIUM FALCIPARUM / 第二军医大学学报

Glycophorin A(GPA)of human erythrocyte membrane is closely related with the invasion of erythrocytes by Plasmodium falciparum. Under the condition of the in vitro culture, the effects of GPA, anti-GPA-IgG, ?1-acid glycoprotein, wheat germ agglutinin, etc. on the invasion of erythrocytes by Plasmodium falciparum were observed in the research. The results showed that the combination of GPA with Plasmodium falciparum merozoites has high specificity, high affinity and a tendency to saturation, and produces specific biological effects. These confirm for the first time from the characteristics of the ligand-receptor interaction that GPA is a recptor recognized and bound by Plasmodium falciparum merozoites.