Cytokinesis ; Micronucleus Tests

OBJECTIVEAlkaline comet assay was used to evaluate DNA repair (nucleotide excision repair, NER) capacity of human fresh lymphocytes from 12 young healthy non-smokers (6 males and 6 females).

METHODSLymphocytes were exposed to UV-C (254 nm) at the dose rate of 1.5 J/m2/sec. Novobiocin (NOV) and aphidicolin (APC), DNA repair inhibitors, were utilized to imitate the deficiency of DNA repair capacity at the incision and ligation steps of NER. Lymphocytes from each donor were divided into three grougs: UVC group, UVC plus NOV group, and UVC plus APC group. DNA single strand breaks were detected in UVC irradiated cells incubated for 0, 30, 60, 90, 120, 180, and 240 min after UVC irradiation. DNA repair rate (DRR) served as an indicator of DNA repair capacity.

RESULTSThe results indicated that the maximum DNA damage (i.e. maximum tail length) in the UVC group mainly appeared at 90 min. The ranges of DRRs in the UVC group were 62.84%-98.71%. Average DRR value was 81.84%. The DRR difference between males and females was not significant (P < 0.05). However, the average DRR value in the UVC plus NOV group and the UVC plus APC group was 52.98% and 39.57% respectively, which were significantly lower than that in the UVC group (P < 0.01).

CONCLUSIONThe comet assay is a rapid, simple and sensitive screening test to assess individual DNA repair (NER) capacity. It is suggested that the time to detect DNA single strand breaks in comet assay should include 0 (before UV irradiation), 90 and 240 min after exposure to 1.5 J x m(-2) UVC at least. The DRR, as an indicator, can represent the individual DNA repair capacity in comet assay.

Adult ; Aphidicolin ; pharmacology ; Comet Assay ; methods ; DNA Damage ; drug effects ; radiation effects ; DNA Repair ; drug effects ; genetics ; radiation effects ; Enzyme Inhibitors ; pharmacology ; Female ; Humans ; Lymphocytes ; drug effects ; metabolism ; radiation effects ; Male ; Novobiocin ; pharmacology ; Risk Assessment ; Time Factors ; Ultraviolet Rays ; adverse effects

OBJECTIVETo assess DNA repair capacity of human lymphocytes with comet assay.

METHODSFresh lymphocytes form twelve 26-year old donors (6 males, 6 females) were exposed to ultraviolet C (UVC, 254 nm) at the dose rate of 1.5 J/m(2). The lymphocytes of each donor were divided into three parts: UVC group, UVC + aphidicolin (APC) group, UVC + novobiocin (NOV) group. DNA single strand breaks were detected with comet assay in UVC-irradiated cells and unirradiated cells incubated for 30, 60, 90, 120, 180 and 240 min. DNA repair rate (DRR) was calculated and served as an indicator of DNA repair capacity.

RESULTSThe maximum average comet tail length (MTL) in three groups appeared 90 min after UVC exposure. The DRR range of UVC group was 81.84% (62.84% - 98.71%); There was no significant difference in DRR between males and females (P > 0.05). However, the average DRRs of UVC + NOV group and UVC + APC group (52.98% and 39.57% respectively) were significantly lower than that of UVC group (P < 0.01).

CONCLUSIONComet assay is a rapid and simple screening test to assess DNA repair capacity. DRR, as an indicator, may express the individual DNA repair capacity.

Aphidicolin ; pharmacology ; Comet Assay ; methods ; DNA ; drug effects ; genetics ; radiation effects ; DNA Repair ; Enzyme Inhibitors ; pharmacology ; Female ; Humans ; Lymphocytes ; drug effects ; metabolism ; radiation effects ; Male ; Novobiocin ; pharmacology ; Ultraviolet Rays

Background:Chronic kidney disease (CKD) is an independent risk factor for cardiovascular disease (CVD).However,the association between CKD and CVD risk in patients with type 2 diabetes mellitus (T2DM) in China has not yet been well investigated.This study aimed to determine the association of CKD with the risks of coronary heart disease (CHD) and stroke in a Chinese population with T2DM.Methods:A total of 1401 inpatients with T2DM at the Second Affiliated Hospital of Zhejiang University School of Medicine between April 2008 and November 2013 were included in this study.The CKD-Epidemiology Collaboration equation for Asians was used to classify CKD.The UK Prospective Diabetes Study risk engine was used to estimate the risks of CHD and stroke.Results:CHD risk was significantly increased with CKD stage (20.1％,24.8％,and 34.3％ in T2DM patients with no CKD,CKD Stage 1-2,and Stage 3-5,respectively;P ＜ 0.001 for all).The stroke risk was also increased with CKD stage (8.6％,12.7％,and 25.4％ in T2DM patients with no CKD,CKD Stage 1-2,and Stage 3-5,respectively;P ＜ 0.001 for all).Compared with no-CKD group,the odds ratios (ORs) for high CHD risk were 1.7 (P ＜ 0.001) in the CKD Stage 1-2 group and 3.5 (P ＜ 0.001) in the CKD Stage 3-5 group.The corresponding ORs for high stroke risk were 1.9 (P ＜ 0.001) and 8.2 (P ＜ 0.001),respectively.Conclusion:In patients with T2DM,advanced CKD stage was associated with the increased risks of CHD and stroke.

OBJECTIVETo detect the response of lymphocytes to radiation in untreated breast cancer patients with three different genetic assays.

METHODSBlood samples were collected from 25 untreated patients and 25 controls. Each blood sample was divided into two parts: one was irradiated by 3-Gy X-ray (irradiated sample), the other was not irradiated (non-irradiated sample). The radiosensitivity of lymphocytes was assessed by comet assay, cytokinesis-block micronucleus (CBMN) assay and 6-TG-resistant cells scored (TG) assay.

RESULTSThe baseline values of micronucleated cell frequency (MCF) and micronucleus frequency (MNF) in the patients were significantly higher than those in the controls (P < 0.01), and 3-Gy X-ray induced genetic damage to lymphocytes in the patients increased significantly as compared with that in the controls as detected with the three genetic assays (P < 0.01). The proportion of radiosensitive cases in the patient group was 48% for the mean tail length (MTL), 40% for the mean tail moment (MTM), 40% for MCF, 44% for MNF, and 48% for mutation frequencies of the hprt gene (Mfs-hprt), respectively, whereas the proportion of radiosensitive cases in the control group was only 8% for all the parameters.

CONCLUSIONThe difference in the lymphocyte radiosensitivity between the breast cancer patients and the controls is significant. Moreover, there are wide individual variations in lymphocyte radiosensitivity of patients with breast cancer. In some cases, the radiosensitivity of the same patient may be different as detected with the different assays. It is suggested that multiple assays should be used to assess the radiosensitivity of patients with breast cancer before therapy.

Breast Neoplasms ; blood ; genetics ; Carcinogenicity Tests ; Case-Control Studies ; Comet Assay ; Cytokinesis ; radiation effects ; Drug Resistance ; Female ; Humans ; Lymphocytes ; metabolism ; pathology ; radiation effects ; Micronucleus Tests ; Middle Aged ; Radiation Tolerance ; radiation effects ; Thioguanine ; X-Rays

OBJECTIVETo study genetic damage of workers alone occupationally exposed to methotrexate (MTX) with three end-points.

METHODSThe blood samples from 21 workers exposed to MTX and 21 controls were detected with micronucleus test, comet assay, hprt gene mutation test and TCR gene mutation test.

RESULTSThe mean micronuclei rate (MNR) and mean micronucleated cells rate (MCR) in 21 workers were 10.10 per thousand +/- 0.95 per thousand and 8.05 per thousand +/- 0.75 per thousand, respectively, which were significantly higher than those (5.48 per thousand +/- 0.82 per thousand and 4.38 per thousand +/- 0.58 per thousand) in control (P < 0.01). The mean tail length (MTL) of 21 workers and 21 controls were (1.30 +/- 0.06) microm and (0.07 +/- 0.01) microm, respectively, there was significant difference between workers and controls (P < 0.01). But the difference between workers and controls for mean tail moment (MTM) was not significant (P > 0.05). The average mutation frequency (Mf-hprt) of hprt and (Mf-TCR) of TCR in workers were 1.00 per thousand +/- 0.02 per thousand and (6.87 +/- 0.52) x 10(-4), respectively, which were significantly higher than those [0.86 per thousand +/- 0.01 per thousand and (1.67 +/- 0.14) x 10(-4)] in control (P < 0.01).

CONCLUSIONThe genetic damage to some extent appeared in workers occupationally exposed to methotrexate.

Adult ; Comet Assay ; DNA Damage ; Female ; Humans ; Hypoxanthine Phosphoribosyltransferase ; genetics ; Male ; Methotrexate ; toxicity ; Micronucleus Tests ; Middle Aged ; Mutation ; Occupational Exposure

OBJECTIVETo observe the influence of 1.8 GHz microwave (MW) specific absorption rate (SAR, 3 W/kg) on human lymphocytes DNA damage induced by 4 chemical mutagens [mitomycin C (MMC), bleomycin (BLM), methyl methanesulfonate (MMS), and 4-nitroquinoline 1-oxide (4NQO)].

METHODSComet assay in vitro was used to detect human lymphocyte DNA damage induced by 1.8 GHz MW, 4 chemical mutagens, and MW plus 4 chemicals 0 h and 21 h respectively after exposure. The time exposed to MW or mutagens was 2 h or 3 h respectively. The results were showed by tail length (TL) and tail moment (TM).

RESULTSThe difference of DNA damage between MW group and control group was not statistically significant (P > 0.05). DNA damages in MW plus MMC groups and MW plus 4NQO groups were significantly greater than those in the corresponding concentrations of MMC groups and 4NQO groups (P < 0.01 or P < 0.05). However, MW did not enhance DNA damage induced by MMS and BLM (P > 0.05).

CONCLUSIONExposure to 1.8 GHz (SAR, 3 W/kg) microwave may not induce human lymphocyte DNA damage, but could enhance DNA damage induced by MMC and 4NQO.

4-Nitroquinoline-1-oxide ; toxicity ; Adult ; Bleomycin ; toxicity ; Cells, Cultured ; Comet Assay ; DNA ; drug effects ; DNA Damage ; Humans ; Lymphocytes ; drug effects ; radiation effects ; Male ; Methyl Methanesulfonate ; toxicity ; Microwaves ; adverse effects ; Mitomycin ; toxicity ; Mutagens ; toxicity

OBJECTIVETo study whether 1.8 GHz microwaves (MW) (SAR, 3 W/kg) exposure can influence DNA damage induced by ultraviolet ray (UV).

METHODSThe lymphocytes were obtained from three young healthy donors. The cells were exposed to 254 nm UV at the doses of 0.25, 0.50, 0.75, 1.00, 1.50 and 2.00 J/m(2). The lymphocytes were also exposed to 1.8 GHz MW (SAR, 3 W/kg) for 0, 1.5 and 4.0 h. The combination exposure of UV plus MW was conducted. The treated cells were incubated for 0, 1.5 and 4.0 h. Finally, comet assay was used to detect DNA damage of above treated lymphocytes.

RESULTSThe difference of DNA damage induced between MW group and control group was not significant (P>0.05). the MTLs induced by UV were (1.71+/-0.09), (2.02+/-0.08), (2.27+/-0.17), (2.27+/-0.06), (2.25+/-0.12), (2.24+/-0.11)microm, respectively, which were significantly higher than that of control [(0.96+/-0.05) microm], (P<0.01). MTLs of some sub-groups in combination exposure groups at 1.5 h incubation were significantly lower than those of corresponding UV sub-groups (P<0.01 or P<0.05. However, MTLs of some sub-groups in combination exposure groups at 4.0 h incubation were significantly higher than those of corresponding UV sub-groups (P<0.01 or P<0.05).

CONCLUSIONThe exposure to 1.8 GHz (SAR, 3 W/kg) MW for 1.5 and 4.0 h can not enhance significantly human lymphocyte DNA damage. But MW can reduce or enhance DNA damage of lymphocytes induced by UV at 1.5 h and 4.0 h incubation in comet assay in vitro, respectively.

Adult ; Cells, Cultured ; DNA Damage ; radiation effects ; Female ; Humans ; Lymphocytes ; radiation effects ; Male ; Microwaves ; Ultraviolet Rays ; adverse effects

OBJECTIVETo investigate the cyto-genotoxicity of cigarette smoke condensates (CSCs) in human peripheral blood lymphocytes with different assays in vitro.

METHODSHuman lymphocytes were exposed to particle matter of cigarette smoke combined with or without S9 mixtures at doses of 25, 50, 75, 100 and 125 microg/ml for 3 h. The cytotoxicity induced by CSCs was detected by CCK-8 assay. The DNA damage, DNA repair (repair time: 30, 60, 90, 120 and 240 min, respectively) and the somatic cell mutations induced by 75 microg/ml CSCs were measured by comet assay, hprt gene and TCR gene mutation tests, respectively.

RESULTSCCK-8 assay indicated that the cell viability decreased with CSCs doses. At the doses of 100, 125 microg/ml, the cell viability of CSCs +S9 group was significantly higher than that of CSCs -S9 group (P < 0.05, P < 0.01). In comet assay, DNA damage significantly increased in a dose-dependent manner, as compared with controls (P < 0.01). Moreover, there was significant difference between -S9 group and +S9 group (P < 0.05, P < 0.01). The Mf-TCR at each dose group was significantly higher than that of controls (P < 0.05, P < 0.01). The Mf-hprt at high-dose groups were significantly higher than that of controls (P < 0.01), and significant difference of Mf-TCR and Mf-hprt at high doses of CSCs between -S9 group and +S9 group (P < 0.05, P < 0.01). The DNA damage induced by CSCs +S9 or CSCs -S9 could be repaired, but DNA repair speed was different between -S9 group and +S9 group (P < 0.05, P < 0.01).

CONCLUSIONCSCs may induce cyto-genotoxicity in human peripheral blood lymphocytes in vitro, but S9 mix could reduce the toxicity of CSCs and impact DNA repair speed.

Cells, Cultured ; Comet Assay ; DNA Damage ; drug effects ; DNA Repair ; drug effects ; Humans ; Lymphocytes ; drug effects ; Male ; Mutation ; Tobacco Smoke Pollution ; adverse effects ; Young Adult

Objective:Summarize the experience of the medical rescue team at the main landing site of China's manned space mission, analyze the new characteristics of the Shenzhou 12 space station mission, and take corresponding countermeasures and measures to ensure the strong medical rescue guarantee for astronauts.Methods:Search the publications about astronaut medical aid domestic and abroad, summarize the rescue and medical aid experiences from Shenzhou 5 to Shenzhou 11. In consideration of prolonged on-orbit time, Location adjustment of the landing site and the new characteristics of the complex terrain, new targeted strategies were presented.Results:The astronauts flew in orbit for 90 days, and the main landing site and launch site are in the same area. The medical security includes three parts: launch section, running section and return section. Desert rescue model were added. Ten injuries were simulated and each injury first-aid procedure was standardized.Conclusion:After targeted improvement and optimization, the Shenzhou 12 astronauts medical rescue support program ensures the safety of the whole process, all-weather and all-terrain emergency and rear delivery of the astronauts in the new mission environment and complex terrain.