In vitro Antigenotoxicity of Ulva rigida C. Agardh (Chlorophyceae) Extract against Induction of Chromosome Aberration, Sister Chromatid Exchange and Micronuclei by Mutagenic Agent MMC

Objective To determine the in vitro possible clastogenic and cytotoxic activities of Ulva rigida crude extracts （URE）, and identify their antigenotoxic and protective effects on chemotherapeutic agent mitomycine-C （MMC）. Methods Anti-clastogenic and anti-genotoxic activities of Ulva rigida crude extracts （URE） were studied using chromosome aberration （CA）, sister chromatid exchange （SCE）, and micronuclei （MN） tests in human lymphocytes cultured in vitro. Results The chromosome aberration, sister chromatid exchange or micronuclei tests showed that URE at concentrations of 10, 20, and 40 lag/mL had no clastogenic activity in human lymphocyte cell culture. Three doses of URE significantly decreased the number of chromosomal aberrations and the frequencies of SCE and MN when compared with the culture treated with MMC （P〈0.0001）. Conclusion Although URE itself is not a clastogenic or cytotoxic substance, it possesses strong antigenotoxic, anti-clastogenic, and protective effects on MMC in vitro.

Sister chromatid exchange and DNA damage in human lymphocytes induced by air-dust in Lanzhou City: involvement in free radicals

The air-dust samples collected from petro-chemical industrial region in the suburb of Lanzhou and from a certain rural region 64 km away from the city were extracted, with a mixed solvent (benzene: hexane: isopropanol=7:2:1) for 8 hours. A strong free radical signal at g= 2.00 of air-dust itself and a hyperfine splitting EPR signal of extract from air-dust have been detected. The sister chromatid exchange frequency (SCE) was increased by extracts of both dusts from the industrial region and from the rural region. If a chemical is able to increase SCE up to twice as high as the control, this chemical is considered to be mutagenic and/or carcinogenic. The double SCE frequency concentration is 23 μg/ml for the dust extract obtained from the industrial region and 47μg/ml for that from the rural region. Extracts were able to damage to DNA template. Results indicated that the mutagenicity and/or carcinogenicity of the extracts obtained from the petro-chemical industrial region were stronger than that of the extracts from the rural region.

Non-genotoxicity of Dental Monomer Siloranes in the Sister Chromatid Exchange Assay with Cultured Mammalian Cells

目的:Siloranes是一种含硅的新型牙科复合树脂环氧乙烷单体,较传统的含碳的环氧乙烷单体具有更好的生物相容性。本研究的目的为用哺乳动物细胞培养检测姐妹染色体交换的方法评估Siloranes的基因毒性,并与传统的环氧乙烷比较。方法:研究所用的传统环氧乙烷为CyracureTM UVR6105。Silorane包括Ph-Sil,TET-Sil和二者50/50(w/w)的混合物(3M-ESPE)。用CHO细胞在有或无S9情况下检测姐妹染色体交换(SCE)。Bonferron post hoc统计分析检测有无显著性差异。结果:与溶剂对照相比,在有或无S9情况下,环氧乙烷UVR6105显著性地增加了培养CHO细胞的SCE数目。3种Silorane单体Ph-Sil,TET-Sil或Sil-Mix均未能增加SCE数目。结论:用哺乳动物细胞培养检测姐妹染色体交换的方法评估显示,3种新型Silorane单体Ph-Sil,TET-Sil或Sil-Mix均未检测出基因毒性效果,提示Silorane单体具有较低基因毒性,是适于研发牙科树脂的新型单体。

OBSERVATION ON PERIPHERAL BLOOD LYMPHOCYTE SISTER CHROMATID EXCHANGES IN PAINTING WORKERS

This paper reports the peripheral bloodlymphocyte sister chromatid exchanges (SCE) in 95painters.The freqency of SCE was 5.49±1.21(SCE/cell ±SE).There was statistical significantdifference (P【0.01) as compared with 27 individualsin control group.It seemed to be a tendency that

SISTER CHROMATID EXCHANGES FREQUENCY IN PATIENTS WITH MONONUCLEOSIS

Biomonitoring with cytogenetic methods consistto compare a known or suspected exposed groups with acontrol group with different endpoints.Generallyfactors which may influence the baseline levels ofsister chromatid exchanges frequency fall in 2 cate-gories:technical and biological factors.In additionto age,sex,drug use,smoking habits,health statusmight also be relevant.During a long term survey ofpeople professionally exposed to ethylene oxide

Is there a connection between synthetic bone grafts and sisters chromatide exchange?

Background: In oral and maxillofacial surgery, synthetic bone grafts are most widely used as bone substitutes, due to the limited sources of autologous bone. The aim of this study was to examine the influence of three different synthetic bone grafts (Cerasorb, Fortoss and Perioglass) on sisters chromatide exchanges (SCEs) in peripheral lymphocytes. Materials and Methods: Peripheral blood samples taken from 68 patients (45 females and 23 males), who underwent oral surgery procedures, such as apical resection, cyst enucleation or periodontal curretage, were obtained for SCE a day before and two months after the surgeries. A control group included 30 patients, while the study group was made of the patients who underwent bone grafting with Cerasorb? (11 patients), Fortoss? VITAL (10 patients) or Perioglass? (17 patients). Results: Comparing with the results of the study group before and after the treatment, it was concluded that the results were statistically significant (p = 0.001). In the Perioglass? subgroup, a greater statistical significance (p = 0.003) was noted, than that in either the Cerasorb? (p = 0.620) or Fortoss? (p = 0.210) subgroups, in which there was no statistical significance. Conclusions: Although further investigations may be necessary, our results suggest that the synthetic bone grafts might have an influence on SCE in peripheral lymphocytes.

On the regulation of PP2A and its role in controlling sister chromatid cohesion and microtubule-kinetochore attachment

Protein phosphatase 2A(PP2A)plays a critical multi-faceted role in the regulation of the cell cycle.PP2A is involved in such diverse processes by the formation of structurally distinct families of holoenzymes,which are regulated spatially and temporally by specific regulators.Mitosis requires the correct arrangement of sister chromatids so that replicated chromosomes can bind correctly to microtubules and segregate towards opposite poles.A large number of studies have shown that PP2A is mainly involved in a series of phosphorylation processes during the G2/M phase transition and the termination of M phase.Moreover,PP2A shows a more substantial contribution to sister chromatid cohesion and microtubule-kinetochore attachment.These processes are all crucial for proper cell survival and proliferation and are often deregulated in cancer and other diseases.

A Comparative Study of Humanistic Exchange and Cooperation between China and Southeast Asian in the Perspective of "the Belt and Road" Initiative

In the exchanges between different countries,apart from enhancing political mutual trust and strengthening pragmatic cooperation,it is of great importance to forging humanistic exchange.With a long history of exchanges between China and all the countries in South-east Asia,the humanistic exchange between China and South-east Asia has been continuing since the founding of the People's Republic of China.After the establishment of China-ASEAN dialogue relations,the strategic position of humanistic exchange has been rapidly improved.By means of the case study of Confucius Institute,sister cities,and tourism cooperation,the author has found that humanistic exchange between China and South-east Asia has enjoyed a long history and embodied profound and extensive meaning.It is the ancient Maritime Silk Road that helped to form the exchanges between China and South-east Asia.In the meantime,it is the 21st-Century Maritime Silk Road that has deepened this friendship.The successful experience of humanistic exchange and cooperation between China and South-east Asia has not only consolidated the China-ASEAN strategic partnership but also provided a conducive reference for people-to-people ties in the implementation of the Belt and Road Initiative.In addition,it has added dynamics and confidence to the building of a community with a shared future for mankind which is propelled by China's humanistic diplomacy.

DETECTION OF SISTER CHROMATID EXCHANGES IN MOUSE SPERMATOGONIA IN VIVO

Sister chromatid exchanges (SCE) can be detected and a clear demarcation between sister chromatids can be obtained by incorporating 5-bromo-2′-deoxyuridine (BrdU) into chromosomal DNA throughout two rounds of replication period and with the sister chromatid differential staining technique. Numerous experiments have proved that SCEs are very sensitive indicators of mutagens and carcinogens. This

COMPARATIVE STUDIES ON SISTER CHROMATID EXCHANGES INDUCED BY MITOMYCIN C IN HUMAN AND RABBIT LEUKOCYTES

In recent years, cytogenetic studies show that sister chromatid exchanges (SCE) during mitosis in higher organisms are the exchanges between DNA double-strands, and the frequencies of exchanges may be enhanced when cells are treated with various exogenous agents. Furthemore, the formation of SCE is closely related to the

自然流产女性117例染色体结构稳定性研究

目的:观察自然流产女性外周血淋巴细胞姐妹染色单体互换(sister-chromatid exchange,SCE)频率,探讨SCE与自然流产之间的关系。方法:收集自然流产女性117例为观察组,收集同期健康育龄女性50名为对照组,按SCE检测方法检测2组受试者外周血淋巴细胞,计数SCE互换频率。结果:观察组和对照组女性外周血淋巴细胞SCE互换频率分别为(8.04±2.30)次和(6.43±1.50)次,2组差异有统计学意义(P<0.01)。结论:女性自然流产可能与SCE互换频率异常有关。

以鲁班工坊为契机,持续发展多元国际交流合作

天津市已在亚非欧三大洲19个国家建成20个鲁班工坊,可开设世界职业院校技能大赛项目30项,可与19个国家城市形成国际友城。以交流合作为主要抓手,与友城共享先进的发展理念,讲好“中国故事”“天津故事”,为提升天津对外影响力和知名度发挥着积极的促进作用。

Valuable exchanges between Xi'an and foreign sister cities in pandemic

Nara,Japan,was the first city to establish sister city ties with Xi’an in May 1974.Since then,Xi’an has remained open for international sister city exchanges.Over the past four decades,the international network of Xi’an has been expanding.Even when confronting various difficulties brought by COVID-19,Xi’an has never slowed its pace of facilitating valuable cross-cultural exchanges with cities around the globe.

International sister city exchanges exhibition

On the evening of Dec 29,2017,A Close Friend from Afar Brings Distant Land Near:Chengdu International Sister City Exchanges Exhibition opened at the Chengdu Museum.The unique Tulip Chair from the Netherlands,the exquisite Sousse Tin Olive Branch from Tunisia,the delicate Drum from Gimcheon,Republic of Korea,the indigenous Waka Bowl from New Zealand,the mysterious Talisman Pendant from Canada and many other gifts from Chengdu’s international sister

高氟对人体DNA稳定性的影响

本文对33例地方性慢性氟中毒患者进行了细胞遗传学检查。结果表明:氟中毒患者外周血淋巴细胞微核率和姊妹染色单体交换频率明显高于对照组,经统计学处理,都有显著性差异(P<0.01)。说明高氟可造成不同类型的 DNA 损伤。

金匮肾气丸延缓衰老作用的实验研究

目的：探讨金匮肾气丸延缓衰老作用的机理。方法：用环磷酰胺（ＣＰＰ）诱致小鼠骨髓细胞ＤＮＡ损伤，以微核（ＭＮ）和姐妹染色单体互换（ＳＣＥ）为指标，观察温补肾阳、延缓衰老代表方金匮肾气丸的抗ＤＮＡ损伤作用。结果：金匮肾气丸对由环磷酰胺所致ＤＮＡ损伤具有良好的拮抗作用。结论：提高机体抗ＤＮＡ损伤能力可能是金匮肾气丸延缓衰老作用的主要机理所在。

甲醛对雄性小鼠生殖细胞遗传物质的影响及其机制

目的 研究甲醛对各阶段生殖细胞遗传物质的损伤及其机制。方法 选用雄性昆明种小鼠为研究对象 ,甲醛染毒剂量分别为 0 2 ,2 ,2 0mg/kg。采用腹腔注射染毒 5d ,第 6天处死一批小鼠 ,余下的小鼠于第 14天处死。观察不同阶段生殖细胞遗传物质的损伤和生物材料中脂质过氧化物丙二醛 (MDA)、铜和锌的变化。结果 甲醛能诱发早期精细胞微核率和精原细胞SCE频率显著升高 ;甲醛高剂量组能使小鼠睾丸组织中MDA含量明显升高 ,Cu和Zn的含量显著降低。结论 甲醛能诱发小鼠生殖细胞遗传物质的损伤 ,睾丸组织脂质过氧化损伤 ;脂质过氧化作用可能是甲醛致遗传物质损伤的机制之一。

稀土元素钬对蚕豆根尖细胞姊妹染色单体互换的影响

背景与目的 :研究稀土元素钬对蚕豆根尖细胞姊妹染色单体互换的影响。 材料与方法 :将蚕豆初生根浸入10-4 mol/L5_BrdU溶液中 ,23℃避光培养18h ,然后把实验组蚕豆转移到硝酸钬溶液中 ,23℃避光培养4h,对照组蚕豆转移到去离子水中23℃避光培养4h。再把实验组、对照组蚕豆分别转移到10 -4mol/L5_BrdU溶液中继续在23℃避光条件下培养17h。切取根尖,在23℃避光条件下用0.05 %秋水仙素处理3.5h,固定液固定3.5h ,盐酸水解 ,Schiff试剂染色 ,制片 ,镜检 ,统计SCE频率/细胞。结果 :各剂量组的硝酸钬溶液均能诱导蚕豆根尖细胞SCE频率显著上升 ,并且细胞核异常现象明显。结论

4种方药对环磷酰胺诱发的SCE的抑制作用

目的:对中医常用滋阴补阳方药进行筛选。方法:以ICR纯种小鼠的骨髓细胞为实验材料,用公认的诱变剂环磷酰胺(CPP)诱发的姐妹染色单体互换(SCE)作为指标,研究六味地黄汤、金匮肾气丸、理中汤及桂枝甘草汤对环磷酰胺诱导的SCE的影响。结果:4种方药对SCE均具明显的抑制作用。

苯并（a）芘对人血淋巴细胞的细胞遗传学损伤研究

以不同浓度苯并（ａ）芘（ＢａＰ）对人血淋巴细胞进行体外染毒，运用微核（ＭＮ）、染色体畸变（ＣＡ）和姊妹染色单体交换（ＳＣＥ）试验，综合评价了ＢａＰ对人血淋巴细胞的细胞遗传学损伤作用。结果表明，经Ｓ９代谢活化，ＢａＰ可诱发细胞ＭＮ率、ＣＡ率和ＳＣＥ率显著增高，并呈现明显浓度－反应关系。上述三指标的变化相互间呈高度正相关。三项指标中与ＢａＰ染毒浓度的对数值呈高度正相关。三项指标中ＳＣＥ试验的浓度－反应关系最好，敏感性和精密度最高。