应用染色体G显带技术评估辐射剂量和染色体畸变的量效关系

目的:应用染色体G显带技术观察4MV的X线辐射后的染色体畸变情况,分析不同类型的染色体畸变和辐射剂量的关系.方法:以4MV的X线0.5、1、2、4 Gy对离体人外周血进行辐照,其淋巴细胞培养后,采用染色体G显带分析不同类型的染色体畸变率.结果:染色体双着丝粒、缺失、易位以及片段畸变和辐射剂量呈线性正相关,其线性趋势线和R<'2>值依次分别为:Y=24.1X-13.3(R<'2>=0.975);Y=10.5X-2.7(R<'2>=0.887);Y=30.2X-17.8(R<'2>=0.913);Y=53.3X-38.7(R<'2>=0.976).结论:染色体G显带技术可以较非显带技术提供更多更准确的畸变信息,为进一步研究提供借鉴.     

不同剂量电离辐射对小鼠脾脏调节性T细胞及TGF-β1表达的影响

目的:观察不同剂量X射线照射后小鼠脾脏调节性T细胞(Treg)和转化生长因子-β1(TGF-β1)表达的变化,探讨X射线对Treg阳性率及TGF-β1表达水平的影响.方法:雄性ICR小鼠,用X.S.S.205(FZ)型固定式X射线深部治疗机进行不同剂量的全身照射(低剂量组为0.050、0.075、0.100和0.200 Gy;高剂量组为0.500、1.000、2.000、4.000 和6.000 Gy),同时设立假照组,于照射后16 h处死小鼠,取脾脏,分别采用流式细胞术、RT-PCR及Western blotting法检测Treg和TGF-β1的表达水平.结果:与假照组比较,低剂量照射组小鼠脾脏Treg阳性率无明显变化(P>0.05);高剂量照射组,1.000 Gy照射后开始脾脏Treg阳性率明显高于假照组(P<0.05,P<0.01),并呈剂量依赖性升高.与假照组比较,小鼠脾脏细胞TGF-β1 mRNA表达水平从0.500 Gy剂量组开始升高,2.000 Gy组达到假照组的2倍以上,但随后略有下降;在低剂量照射范围时,0.100 Gy组小鼠TGF-β1蛋白表达水平明显高于假照组(P<0.05),而在大剂量组呈递增趋势,4.000 Gy和6.000 Gy组与假照组比较差异有统计学意义(P<0.05).结论:在高剂量X射线诱导下小鼠脾脏Treg阳性率增高,同时TGF-β1分泌增加,这种变化可能是高、低剂量X射线诱导不同免疫效应的又一原因.     

Taurolidine联合X射线对小鼠恶性黑色素瘤细胞周期进程的影响

目的:观察taurolidine联合X射线照射对小鼠恶性黑色素瘤(B16-4A5和B16-F10)细胞周期进程的影响,探讨其诱导肿瘤细胞凋亡的发生机制.方法:选择B16-4A5和B16-F10细胞系按给药浓度随机分为4组,taurolidine剂量分别为0、25、50和100 μmol·L-1,同时进行1、2和4 Gy X射线照射,采用流式细胞术检测细胞凋亡率和细胞周期,Western blotting分析cyclin B、cdc2和caspase-3的表达.结果:与25 μmol·L-1 taurolidine组比较,50和100 μmol·L-1 taurolidine组诱导B16-4A5和B16-F10细胞发生G0/G1期阻滞,细胞数分别升高54.9%、73.7%和36.8%、55.5%(P＜0.05); 50 μmol·L-1 taurolidine联合2和4 Gy X射线照射组,细胞G2/M期阻滞消除,细胞数分别降低52.1%、44.2%和59.3%、52.7%(P＜0.05).与对照组、单纯taurolidine组及单纯照射组比较,联合4 Gy X射线照射组cyclin B和cdc2的表达降低,caspase-3的表达升高(P＜0.05).结论:taurolidine联合X射线照射可去除G2/M期阻滞,可选择地抑制肿瘤细胞cyclin B和cdc2的表达、增强caspase-3的表达,共同诱导细胞凋亡.     

低剂量电离辐射诱导小鼠睾丸中细胞色素c和caspase-3表达的变化

目的:研究低剂量电离辐射诱导小鼠睾丸中细胞色素c(Cyt c)和caspase-3表达的变化,阐明二者对低剂量电离辐射诱导小鼠睾丸细胞凋亡的作用.方法:实验小鼠分为不同剂量(0、0.050、0.075、0.100和0.200 Gy)组与不同时程(0、6、12和24 h)组.采用实时PCR和Western blotting分别检测不同剂量X射线照射后不同时间小鼠睾丸组织中细胞色素c(Cyt c)和caspase-3 mRNA和蛋白表达的变化.结果:实时PCR结果显示,不同剂量X射线照射后12 h,Cyt c和caspase-3 mRNA表达随剂量增加而增加,Cyt c mRNA在0.100 Gy照射时表达最多,而caspase-3则在0.075 Gy照射时表达最多;在0.075 Gy照射时二者蛋白表达最多.0.075 Gy照射后Cyt c和caspase-3 mRNA表达随着时间延长表达增多,24 h时达到最高;二者蛋白表达在12 h时最高.结论:低剂量电离辐射能够诱导小鼠睾丸生精细胞中Cyt c和caspase-3 mRNA和蛋白表达的增加,并且具有剂量和时程规律性.     

表皮生长因子受体单克隆抗体对辐射诱导肺腺癌细胞SPC-A-1的增敏作用

目的:探讨表皮生长因子受体单克隆抗体(C225)作为靶向治疗药物联合放射治疗对肺腺癌细胞系(SPC-A-1)的增敏作用,为临床综合治疗非小细胞肺癌提供理论依据.方法:SPC-A-1细胞体外传代培养6代以上,取对数生长期细胞进行实验.SPC-A-1细胞分为对照组(PBS)、照射组(4 Gy)、C225组(100 nmol·L-1)和照射+ C225组(4Gy+100 nmol·L-1),Hoechst 33258染色后采用荧光显微镜观察细胞凋亡情况.SPC-A-1细胞分别给予0、2、4和8 Gy 6-MV X射线照射后继续培养72 h,收集细胞,分为照射组和实验组(照射+C225组),用流式细胞仪检测细胞凋亡率.SPC-A-1细胞分为对照组(PBS)、C225组(100 nmol·L-1)、照射组(8 Gy)和照射+ C225组(8 Gy+100 nmol·L-1),作用48 h后,采用流式细胞仪检测细胞周期.结果:Hoechst 33258染色后,照射+ C225组凋亡细胞数明显高于照射组和C225组;细胞凋亡实验,实验组细胞凋亡率明显高于相应剂量照射组(P<0.05).细胞周期检测,与对照组比较,C225组G0+G1期细胞增加(P<0.05),照射组G2+M期细胞增加(P<0.05),而照射+C225组G0+G1和G2+M期细胞均增加(P<0.05);与对照组比较,C225组、照射组及照射+C225组S期细胞均下降(P<0.05).结论:C225对SPC-A-1细胞系有放射增敏作用,其机制可能与诱导细胞凋亡和细胞周期G0+G1期阻滞有关.     

MT方案治疗急性单核细胞白血病的疗效及其与染色体核型的关系

目的 研究米托蒽醌联合替尼泊苷(MT)方案在急性单核细胞白血病(M5)诱导缓解中的疗效及患者不良反应,并观察疗效与白血病染色体核型的关系.方法 将33例M5患者按治疗史分两组:初治组23例(A组)、DA(柔红霉素联合阿糖胞苷)或HDA(三尖杉酯碱、柔红霉素和阿糖胞苷)1个疗程无效组10例(B组).按核型预后分两组:预后中等组29例(C组),预后不良组4例(D组),均采用MT方案2个疗程诱导缓解,分别统计4组的临床疗效及患者不良反应.结果 MT方案对A、B组的M5诱导完全缓解(CR)率分别为83%(19/23)及60%(6/10),有效率达91%(21/23)及70%(7/10).C、D组CR率分别为83%(24/29)及25%(1/4),有效率为88%(26/29)及50%(2/4),其中复杂核型CR率为0(0/3),非复杂核型的11q23染色体异常患者一次化疗达CR率100%(4/4).MT方案对M5化疗后白细胞最低点在第(7±3)天出现,为(0.4±0.2)×109/L,白细胞<1×109/L时间达(8±5)d,未见化疗相关死亡病例.结论 MT方案简单有效、较安全,是治疗M5的较佳化疗方案,对1个疗程DA、HDA方案无效者亦可试用.MT方案化疗疗效与核型预后分组有关,对11q23染色体异常的M5患者疗效较好,对复杂核型患者疗效欠佳.     

骨髓间充质干细胞对放射性胸腺损伤的修复作用

目的 观察骨髓间充质干细胞(MSCs)对放射性胸腺损伤的修复作用.方法 C57BL/6小鼠行1.75Gy X 线全身照射,每周1次,连续4周.实验设正常对照组、照射组及照射+MSCs组,于末次照射后30、60、90 d称量各组小鼠体质量.取胸腺组织,计算胸腺质量指数,并通过组织学观察MSCs对胸腺组织损伤的修复作用.结果 辐射组和MSCs组在照射期间体质量下降,在观察期间内,小鼠体质量随时间逐渐增加,并且MSCs组小鼠体质量略高于辐射组.对照组小鼠胸腺指数随周龄增大而逐渐减小,辐射组和MSCs组小鼠随照射后时间的延长胸腺指数逐渐增加,MSCs组90d时胸腺指数与对照组小鼠接近.通过观察病理结果可知,正常对照组小鼠胸腺组织皮、髓质结构清楚.辐射组小鼠30d时胸腺组织淋巴细胞可见变性、坏死,细胞数量减少;60d时辐射组可见胸腺淋巴细胞出现修复性再生与增生;90 d时辐射组可见胸腺瘤癌前病变.MSCs移植30 d时胸腺组织皮质高度增生,髓质缩小,皮髓质内可见新生的淋巴组织;60d时胸腺结构趋于正常.结论 MSCs可促进损伤胸腺再生与修复.     

红景天醇提物对乙醇诱导QZG细胞氧化损伤的保护作用

目的:研究乙醇对氧化应激损伤的作用特点和红景天醇提物的抗氧化作用.方法:采用DPPH自由基生成体系、体外鲁米诺化学发光反应(OH和O<,2><'+>)体系观察红景天醇提物对DPPH自由基、OH和O<,2><'+>化学发光强度的抑制作用以及剂量-效应关系.采用乙醇诱导人正常肝细胞系QZG细胞的氧化应激反应模型,观察红景天醇提物对乙醇诱导细胞活力和氧化应激损伤的保护作用.实验分设红景天醇提物3个不同浓度(50、100、200 mg/L)的预防给药组和治疗给药组、阳性对照组(200 mmol/乙醇干预)和阴性对照组(不加受试物).预防给药组用红景天醇提物预处理QZG细胞12 h后,再加入200 mmol/L乙醇处理6 h,治疗给药组采用红景天醇提物和乙醇同时处理QZG细胞6 h.用MTT试验和生化法测定细胞活力、细胞丙二醛(MDA)、还原型和氧化型谷胱甘肽(GSH、GSSG)和总巯基(T-SH)含量、过氧化氢酶(CAT)、超氧阴离子歧化酶(SOD)活力;免疫印迹法检测细胞抗氧化酶血红素加氧酶-1(HO-1)和核因子相关因子2(NRF-2)蛋白的表达.结果:红景天醇提物对自由基的生成具有显著的抑制作用,呈现较为明显的剂量-效应关系;红景天醇提物可有效保护乙醇所致的肝细胞活力损伤,且治疗组具有明显的剂量-效应关系.与阳性对照组相比,红景天醇提物干预组细胞的MDA含量和GSSG含量下降(P<0.05),GSH和T-SH含量显著升高(P<0.05);CAT和SOD活性也显著升高(P<0.05).免疫印迹测定结果表明,红景天醇提物可以诱导HO-1蛋白和NRF-2蛋白表达上调(P<0.05).结论:红景天醇提物在体外自由基模型中具有较强的抗自由基作用,可保护乙醇导致的QZG细胞氧化损伤,其作用机制可能和抗氧化作用相关.     

三七醇提物对大鼠肝组织体内外抗氧化作用的研究

目的:研究三七(panax notoginseng,PNG)醇提物对大鼠肝组织的体内外抗氧化作用.方法:采用羟自由基(·OH)和超氧阴离子自由基(O2-)两种化学发光体系,观察三七醇提物对化学发光强度的抑制作用;采用过氧基异丙苯(cumene hydroperoxide,CHP)、维生素C(VC)/硫酸亚铁(Fe2+)和四氯化碳(CCl)4/还原型辅酶Ⅱ(NADPH)作为激发剂,建立3种微粒体脂质过氧化(lipid peroxidation,LPO)损伤模型,观察三七醇提物对丙二醛(MDA)生成的抑制作用.用60Co γ射线辐照大鼠建立氧化损伤模型,观察三七醇提物对肝组织的氧化型谷胱甘肽(GSSG)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)含量及活性的影响,以及对MDA生成的抑制作用.结果:在两种化学发光的体系中,三七醇提物对O2-和·OH的抑制率均显著高于阴性对照组(P<0.05),且呈明显剂量-效应关系,三七醇提物对O2-和·OH的IC50分别为1.25和0.625 mg/ml;3种LPO损伤模型中三七醇提物不同浓度组的MDA含量均显著低于对照组(P<0.05);在体大鼠氧化损伤模型实验的肝组织中,三七醇提物不同剂量灌胃组[(50、225和450 mg/(kg·d)],其MDA的含量均较阳性对照组(仅做60Co γ照射)降低(P<0.05);225和450 mg/(kg·d)剂量组CAT活性较阳性对照组显著升高(P<0.05);其450mg/(kg·d)剂量组SOD的活性较阳性对照组显著升高(P<0.05);而225和450 mg/(kg·d)剂量组GSSG含量较阳性对照组显著降低(P<0.05).结论:三七醇提物对体外氧化损伤模型具有很强的抗氧化作用,对辐射引起的大鼠体内肝脏氧化损伤具有一定的抗氧化修复功效,并呈剂量-效应关系.     

氟替卡松/沙美特罗对哮喘患者外周血单个核细胞中辅助性T细胞亚群及气道炎症的影响

目的:探讨氟替卡松/沙美特罗对哮喘患者外周血单个核细胞中辅助性T细胞亚群(Th)及气道炎症的影响,为其临床治疗哮喘提供理论依据.方法:13例慢性持续期中度哮喘患者,给予氟替卡松/沙美特罗连续治疗1.5和3.0个月.检测治疗前后外周血Th亚群(Th1、Th2和Th3)、血清细胞因子及IgE水平,观察诱导痰炎症细胞的变化和临床疗效.结果:氟替卡松/沙美特罗治疗1.5个月时,与治疗前比较,哮喘患者外周血Th3百分数增加、Th2百分数减少(P<0.05),转化生长因子β(TGF-β)、白细胞介素4(IL-4)无明显变化(P>0.05);痰嗜酸细胞(eos)百分比明显降低(P<0.01),血eos及痰中性粒细胞百分比无明显变化;呼气峰流速值 (PEF)、哮喘控制测试(ACT)评分明显增加,PEF变异率明显降低(P<0.01),每日急救药物使用无明显减少.治疗3个月时,与治疗前比较,Th1、Th1/Th2、Th3明显增加,Th2明显减少(P<0.05或P<0.01);IL-4、TGF-β明显降低(P<0.05),干扰素γ(IFN-γ)明显增加(P<0.05);IgE含量无明显变化(P>0.05);血eos、痰eos及痰中性粒细胞均明显降低(P<0.01);PEF、ACT评分明显增加,PEF变异率明显降低(P<0.01),每日急救药物使用次数明显减少(P<0.01).治疗3.0个月与治疗1.5个月时比较,PEF变异率继续降低、ACT评分继续增加(P<0.01).结论:氟替卡松/沙美特罗能提高哮喘患者外周血Th3数量,纠正Th1/Th2失衡,减轻气道炎症和临床症状,且随治疗时间延长,效果进一步提高.     

Sexual orientation and the second to fourth finger length ratio: A meta-analysis in men and women.

The ratio of the lengths of the second and fourth fingers (2D:4D) may serve as a marker for prenatal androgen signaling. Because people are typically unaware of their 2D:4D, its use allows possible effects of early sex hormone regimes and socialization to be disentangled. We conducted a meta-analysis on relationships between 2D:4D and sexual orientation in men and women in 18 independent samples of men and 16 independent samples of women. Collectively, these samples comprised 1,618 heterosexual men, 1,693 heterosexual women, 1,503 gay men, and 1,014 lesbians. In addition to identifying the normative heterosexual sex difference in 2D:4D for both hands, we found that heterosexual women had higher (more feminine) left- and right-hand 2D:4D than did lesbians, but we found no difference between heterosexual and gay men. Moderator analyses suggested that ethnicity explained some between-studies variation in men. These results add to a literature suggesting that early sex hormone signaling affects sexual orientation in women, and highlight the need for further research exploring the relationships among 2D:4D, sexual orientation, and ethnicity in men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Suspected skeletal dysplasias: femur length to abdominal circumference ratio can be used in ultrasonographic prediction of fetal outcome

OBJECTIVES: Skeletal dysplasias are a group of bone growth disorders, some of which can be recognized prenatally. Certain types of skeletal dysplasias result in a lethal fetal outcome. The ability to predict this outcome prenatally would be important in counseling parents. This study evaluated the ratio of femur length to abdominal circumference as a predictor of fetal outcome in cases of suspected skeletal dysplasia. STUDY DESIGN: This 3-year retrospective study identified 18 cases of prenatally suspected skeletal dysplasia from a population of approximately 35,000 fetuses undergoing prenatal ultrasonography. The femur length/abdominal circumference ratio was calculated and compared with fetal-neonatal outcomes and diagnoses. RESULTS: Eighteen cases of suspected skeletal dysplasia were identified, and the femur length/abdominal circumference ratio was found to be a good predictor of fetal outcome independent of gestational age. A ratio < 0.16 resulted in a lethal outcome in nine of nine cases. Conversely, a ratio > or = 0.16 resulted in a diagnosis of a nonlethal form of skeletal dysplasia or a diagnosis that ruled out any form of skeletal dysplasia in nine of nine cases. CONCLUSIONS: The femur length/abdominal circumference ratio may be useful to predict a lethal fetal outcome when ultrasonography indicates a possible skeletal dysplasia.     

Effect of specimen geometry, gage length, and width measurement locations on plastic strain ratio (R-value) in sheet metals

The effects of gage length, width measurement locations, and specimen geometry on plastic strain ratio have been investigated for the AA8011 aluminum alloy and interstitial-free (IF) steel sheets. The specimens were ASTM E 517 to 92a subsize, type A, and type A alternative with, respectively, 37.5, 76, and 57 mm reduced parallel sections and with different fillet radii. In each specimen type, there were differences in axial strains of gage marks and changes in width strain over the reduced parallel section, which depend on the applied axial strain, reduced parallel section legth, and fillet radius. Therefore, the magnitudes of the calculated R-values depend upon gage length, width measurement location, axial strain, and specimen geometry. These dependencies were more pronounced in the high R-value IF steel sheet relative to the low R-value AA8011 aluminum alloy sheet. The dependencies of R-value on gage length and width measurement location are negligible in all AA8011 specimens, while in IF specimens, these dependencies can be neglected only for type A specimens with 12.5-mm fillet radius. It is concluded that the observed differences in the measured R-values for specimens with different geometries can be attributed to the constraints imposed by the shoulders, which affect the width strain measurements and the resulting R-values.     

When does length cause the word length effect?

The word length effect, the finding that lists of short words are better recalled than lists of long words, has been termed one of the benchmark findings that any theory of immediate memory must account for. Indeed, the effect led directly to the development of working memory and the phonological loop, and it is viewed as the best remaining evidence for time-based decay. However, previous studies investigating this effect have confounded length with orthographic neighborhood size. In the present study, Experiments 1A and 1B revealed typical effects of length when short and long words were equated on all relevant dimensions previously identified in the literature except for neighborhood size. In Experiment 2, consonant–vowel–consonant (CVC) words with a large orthographic neighborhood were better recalled than were CVC words with a small orthographic neighborhood. In Experiments 3 and 4, using two different sets of stimuli, we showed that when short (1-syllable) and long (3-syllable) items were equated for neighborhood size, the word length effect disappeared. Experiment 5 replicated this with spoken recall. We suggest that the word length effect may be better explained by the differences in linguistic and lexical properties of short and long words rather than by length per se. These results add to the growing literature showing problems for theories of memory that include decay offset by rehearsal as a central feature. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Limb length discrepancy

The surgical management of LLD has gradually evolved from a time when patients were bedridden in traction for prolong periods of time to the point at which much of the treatment time is spent in mobility. Improved surgical techniques, such as percutaneous epiphysiodesis and distraction osteogenesis, have contributed greatly to the success of surgery for LLD. Factors affecting outcome and patient satisfaction must be weighed carefully before selecting treatment for LLD.     

Sex ratio associated with timing of insemination and length of the follicular phase in planned and unplanned pregnancies during use of natural family planning

This was a multicentred, prospective study of pregnancies among women using natural family planning. The women maintained natural family planning charts of the conception cycle, recording acts of intercourse and signs of ovulation (cervical mucus changes, including peak day and basal body temperature). Charts were used to assess the most probable day of insemination relative to the day of ovulation and length of the follicular phase of the cycle. The sex ratio (males per 100 females) for 947 singleton births was 101.5, not significantly different from the expected value of 105. The sex ratio did not vary consistently or significantly with the estimated timing of insemination relative to the day of ovulation, with the estimated length of the follicular phase or with the planned or unplanned status of the pregnancy. Although these findings may be affected by imprecision of the data, the study suggests that manipulation of the timing of insemination during the cycle cannot be used to affect the sex of offspring.     

The ratio of 2nd to 4th digit length: a predictor of sperm numbers and concentrations of testosterone, luteinizing hormone and oestrogen

The differentiation of the urinogenital system and the appendicular skeleton in vertebrates is under the control of Hox genes. The common control of digit and gonad differentiation raises the possibility that patterns of digit formation may relate to spermatogenesis and hormonal concentrations. This work was concerned with the ratio between the length of the 2nd and 4th digit (2D:4D) in humans. We showed that (i) 2D:4D in right and left hands has a sexually dimorphic pattern; in males mean 2D:4D = 0.98, i.e. the 4th digit tended to be longer than the 2nd and in females mean 2D:4D = 1.00, i.e. the 2nd and 4th digits tended to be of equal length. The dimorphism is present from at least age 2 years and 2D:4D is probably established in utero; (ii) high 2D:4D ratio in right hands was associated with germ cell failure in men (P = 0.04); (iii) sperm number was negatively related to 2D:4D in the right hand (P = 0.004); (iv) in men testosterone concentrations were negatively related to right hand 2D:4D and in women and men LH (right hand), oestrogen (right and left hands) and prolactin (right hand) concentrations were positively correlated with 2D:4D ratio and (v) 2D:4D ratio in right hands remained positively related to luteinizing hormone and oestrogen after controlling for sex, age, height and weight.     

Peribulbar anaesthesia and needle length

This retrospective audit of 87 consecutive patients undergoing routine cataract surgery compared the effect of peribulbar local anaesthesia using 16 mm and 25 mm, 25 gauge needles to administer the anaesthetic. The effect on optic nerve function was observed. There was a significant increase of complete amaurosis in the group where the 16 mm needle had been used. This may be explained by more effective anatomic placement of the 16 mm needle within the orbit, allowing access to the retrobulbar space via fascial septae. There was significantly more lid akinesia with the 16 mm needle. None of this group required an additional facial nerve block, as opposed to 14% of the 25 mm needle group. The use of a 16 mm needle is theoretically safer than a 25 mm needle to administer a peribulbar anaesthetic, in this review it was also demonstrated to be more effective.