两株红杆菌YIM 93620和YIM 9941耐辐射机制研究

目的研究缩短红杆菌(Rubrobacter sp.)YIM93620和YIM9941对紫外线、γ射线照射及低能碳离子注入后的生物学效应,揭示二者的辐射抗性及耐辐射机制。方法分别对这两株菌进行不同剂量的紫外、γ射线照射及低能碳离子注入,以E.coli K-2为阴性对照,绘制致死率曲线;检测DNA损伤修复(Rec A基因)以及辐射过程中耐辐射微生物蛋白酶变化。结果 YIM93620和YIM9941在UV辐照剂量达30 J/m2时,与阴性对照菌比较(1%),受试菌株存活率均高达95%以上。在γ辐照剂量达0.1k Gy时,阴性对照菌株的生存率已经低至21%,而阳性对照株和受试菌株均未见死亡。YIM 93620基因组内Rec A和RecR表达较高(P0.01),而YIM9941基因组内RecR表达较高(P0.01)。YIM 93620和YIM 9941菌体细胞中含有较高的SOD活性和CAT活性,其中YIM93620细胞内的SOD活性比E.coli K-12高5.8倍,CAT活性高26.8倍。结论 YIM 93620和YIM 9941两株菌生长均有强的耐UV和γ射线特性,与其细菌的重组修复和抗氧化特性有关。     

非致死热疗对低剂量率照射的增敏作用

中国仓鼠V_(79)原代细胞在F_(12)培养基中培养(37℃、潮湿、5%CO_2、95%空气、pH=7.3),取指数生长细胞经处理置于T75瓶(2.5×10~5细胞/瓶),37℃培养12h,细胞于Lauda WGW/B水浴中作加热处理,温度变化小于0.05℃;经胰蛋白酶处理、冲洗、计数、形成集落,培养7～9天后固定、染色、测存活率,部分细胞用流式细胞光度计测细胞周期位置.高剂量率照射用15MeV线性加速器,5Gy/min,热处理后立即照射,低剂量率照射用~(60)Co,0.8Gy/min,与加热同时进行,源距细胞180cm.     

~(12)C~(6+)重离子束治疗皮肤鳞状细胞癌临床疗效分析

目的通过应用重离子加速器产生的12C6+束治疗皮肤鳞状细胞癌,评价高线性能量传递在临床治疗的应用。方法 15例经病理证实的皮肤鳞状细胞癌患者,应用80~100 meV/U12C6+重离子束分别给予总剂量43.5~120.6 Gy/5~13次照射,相对生物效应(RBE)等于3。结果 12例患者3月后病变完全消失,达临床治愈(CR);2例缩小75%,达临床部分缓解(PR);总有效率达100%(1例中途终止照射)。治疗中及治疗后照射野皮肤无破溃等放射性损伤。结论 12C6+重离子束具有治疗精度高,疗程短,对肿瘤周围正常组织损伤小等特点。     

褪黑素对重离子辐射损伤小鼠肺的防护作用研究

目的探讨褪黑素(melatonin,MLT)对重离子辐射损伤小鼠肺的防护作用。方法预先给小鼠腹腔注射10mg/kg的MLT,1h后给予0、0.5、1.0、2.0及4.0Gy的全身12C6+束均匀照射,剂量率约1.4Gy/min,辐射后8h,检测辐射损伤小鼠肺组织的SOD活性和MDA、GSH含量,并通过单细胞凝胶电泳技术检测辐射损伤小鼠肺细胞的拖尾长度和尾距。结果和单纯辐射组相比,10mg/kg的MLT腹腔注射能有效抑制重离子辐射引起的小鼠肺组织SOD活性降低、GSH含量下降和MDA含量提高;同时,MLT还能使受损小鼠肺细胞的拖尾长度和尾距显著降低,且都存在剂量效应关系。结论MIT对重离子全身辐射所致小鼠的抗氧化系统有一定的激活效应,对辐射损伤有一定的防护作用,这可能与对抗膜脂质过氧化、清除自由基及其减轻DNA损伤有一定的关系。     

伽玛刀立体定向放疗结合全脑照射治疗脑转移瘤临床效果分析

目的 分析立体定向放疗结合全脑照射治疗脑转移瘤的疗效和预后,同时观察服用替莫唑胺(TMZ)与放疗结合对患者生存率的影响。方法 脑转移瘤患者52例,按照治疗方法不同分为2组,一组为全脑照射(WBRT)+立体定向放疗(SRT,伽玛刀),共35例,一组为单纯SRT,共17例。全脑放疗分次剂量为1.8~3.0 Gy/次,1 次/d,5 次/周,总剂量D_T30~40 Gy,WBRT+SRT组全脑后伽玛刀补量采用45%~75%等剂量曲线包绕PTV,边缘剂量12~15 Gy,中心剂量20~30 Gy。单纯SRT组分次立体定向放疗采用45%~75%等剂量曲线包绕PTV,边缘剂量36~40 Gy,中心剂量70~80 Gy。随访1~2年。所选52例患者中有20例患者放疗期间及放疗后服用替莫唑胺胶囊,同步化疗组化疗方案为:口服替莫唑胺75 mg/m²,1次/d,直至放疗结束,放疗结束后再服用3~6个月,剂量改为150 mg/m²。结果 放射治疗后1~3个月,复查CT/MRI显示总有效率(CR+PR)为84.62%,WBRT+SRT组有效率为88.57%,SRT组有效率为76.47%;肿瘤的6个月及1年的局部控制率分别为92.10%和85.20%。WBRT+SRT组的平均生存期13.2个月,中位生存期11个月;6个月生存率为71.40%,12个月生存率为54.30%,18个月生存率为14.30%。SRT组的平均生存期10.2个月,中位生存期9个月;6个月生存率为41.20%,12个月生存率为23.50%,18个月生存率为5.88%。替莫唑胺+放疗与单纯放疗的6个月、12个月及18个月生存率分别为80.00%和56.30%、60.00%和37.50%、10.00%和12.50%。结论 WBRT+SRT治疗脑转移瘤总体上优于单纯SRT治疗。放疗+TMZ联合治疗与单纯放疗相比,替莫唑胺在放疗过程中服用可提高患者生存率,不良反应无显著增加。     

痤疮丙酸杆菌对抗菌药物的体外抗菌活性分析

目的 研究外伤后细菌性致死性肉芽肿(FBGT)病原菌的培养分离方法并了解常用抗菌药的体外抗菌活性,为该病的诊断和治疗提供实验室依据.方法 采用改良兔脑厌氧增菌肉汤(RRNB)、厌氧琼脂平板置厌氧环境培养,用API鉴定系统20A鉴定板鉴定病原菌;采用肉汤稀释法测定最低抑菌浓度(MIC).结果 从13例FBGT患者中应用RRNB培养基分离到14株病原菌,经ATB/API细菌鉴定系统20A检测,确定为痤疮丙酸杆菌.该菌严格厌氧,培养初期生长极为缓慢,在RRNB中生长良好,但需1～2周时间.环丙沙星对14株病原菌的MIC值均在0.0625～0.5mg/L,青霉素、氨苄西林、氨苄西林/舒巴坦、头孢哌酮、林可霉素、亚安培南/西司他丁的MIC值均在0.125～0.5mg/L,替卡西林/克拉维酸的MIC值为0.25～1.0mg/L,甲硝唑的MIC值为64.0～256.0mg/L.结论 FBGT的病原菌为痤疮丙酸杆菌,该菌对甲硝唑耐药,临床不能用该类药物治疗;青霉素、氨苄西林、林可霉素等常用抗菌药物体外抗菌活性均较高,临床可选择不同种类的抗菌药物联合应用,并与其他疗法联合治疗FBGT.     

144例鼻咽癌常规放疗后鼻窦炎发生的因素分析

目的 探讨鼻咽癌患者常规放疗后鼻窦炎的发生情况及其影响因素。方法 回顾分析本院2000—2005年收治的放疗前无鼻窦炎而放疗后发生鼻窦炎的144例鼻咽癌患者资料,并就其影响因素进行分析。鼻窦炎的诊断用MRI法。T₁+T₂期82例,T₃+T₄期62例。鼻腔受侵58例,无鼻腔受侵86例。鼻咽灶为面颈联合野6 MV X线常规分割照射68~78 Gy, 6~8周,其中>70 Gy 55例、≤70 Gy 89例。颈部为6 MV X线+高能电子线照射,淋巴结阳性者64~74 Gy, 6~8周;阴性者50~54 Gy, 4~5周。结果 全组患者放疗后鼻窦炎总的发生率为86.8%(125例),其中T₃+T₄期的高于T₁+T₂期的,分别为94%(58例)和82%(67例),差异有统计学意义(χ²=4.32, P<0.05);鼻咽灶剂量>70 Gy的高于≤70 Gy的,分别为95%(52例)和82%(73例),差异有统计学意义(χ²=4.65, P<0.05) ;鼻腔受侵的高于未受侵的,分别为95%(55例)和81%(70例),差异有统计学意义(χ²=5.46, P<0.05)。鼻窦炎发生在放疗后3、6、12、>12个月的比例不同,分别占13.6%(17例)、31.2%(39例)、48.8%(61例)及6.4%(8例),差异有统计学意义(χ²=70.48, P<0.01)。结论 鼻咽癌患者常规放疗后鼻窦炎的发生率较高,并在1年内达最高峰;鼻腔有无侵犯、鼻咽照射剂量和T分期与放疗后鼻窦炎的发生有关。     

p~(53)依赖途径的辐射诱导潜在致死损伤的研究

目的 :研究潜在致死损伤 (PL D)是否与 p5 3有关。方法 :采用 12种肿瘤细胞株和 3种人二倍体纤维原细胞株分析辐射敏感性、DNA双链断裂重连接、PL D表达及修复 (PL DR)。其中 7种细胞株 p5 3正常表达 ,8种 p5 3功能缺陷 (6种基因突变 ,2种 HPV 16 E6转染 p5 3表达正常的细胞株 )。取指数生长期 (辐射前低密度培养 18h)和高峰生长期细胞 (待细胞长满后继续培养 3 d以上 ) ,1 3 7　 Csγ射线或 X射线 (剂量率为 1Gy/ min,剂量为 7Gy)照射后立即或于 2 4h以后消化成单细胞悬液 ,培养 2～ 3周 ,固定 ,0 .2 5 %结晶紫染色 ,观察细胞克隆…     

X线辐射体外诱发大鼠肺成纤维细胞恶性转化

本文报告了X线辐射0.5、1.0、3.0及5.0Gy体外诱发WAL-F_1细胞系恶性转化的剂量-效应关系及其细胞生物学特征.细胞转化率(y,%)与剂量(D,Gy)有关,可用下式表达:?3.0Gy照射时转化率最高,为0.41×10~(-1)%.转化细胞生物学特性明显不同于对照细胞,(1)呈上皮样细胞形态;(2)具有持续增殖能力,没有衰老现象,复层生长;(3)染色体核型异常,出现异倍体或多倍体;(4)Con A凝集试验阳性;(5)在半固体琼脂培养基中形成集落;(6)接种于同种动物体内诱发肿瘤.本研究为肿瘤病因学、发病机理及防治研究提供一个良好的实验模型.     

白细胞介素1的辐射防护作用——与红细胞系和粒-巨噬集落形成细胞(GM-CFC)的关系

本文报道纯化的人类白细胞介素1(rIL-1)给予正常和照射小鼠辐射防护剂量20小时后对红细胞系和粒-巨噬集落形成细胞的影响.实验用B6D2F1雌性健康小鼠,12～14周龄,给药组腹腔注射rIL-15.6μg/kg,对照组注射0.5mL生理盐水,给药后20小时照射.~(60)Coγ线,剂量率0.4Gy/min,全身照射6.5、1.0和0.5Gy.结果:6.5Gy照后24小时,给药组与照射对照组的GM-CFC/股骨分别为非照射对照组的1.2±0.6%和1.0±0.3%,给药组经0.5Gy和0.1Gy照后二天,BFU-E/股骨,股骨与牌的CFU-E值均高于照射对照组.rIL-1和生理盐水注入后20小时,对脾细胞数无明显影响,然而rIL-1注射鼠每股骨细胞总数几乎是对照组骨髓细胞数的79%,每个股骨的GM-     

Rays as weapons

PURPOSE: Ionizing radiation is being regarded as life threatening. Therefore, accidents in nuclear power plants are considered equal threatening as nuclear bomb explosions, and attacks with dirty bombs are thought as dangerous as nuclear weapon explosions. However, there are differences between a nuclear bomb explosion, the largest imaginable accident in a nuclear power plant, and an attack with a dirty bomb. It is intended to point them out. METHOD: The processes are described, which damage in a nuclear bomb explosion, in the largest imaginable accident in a nuclear power plant, and in an attack with a dirty bomb. Their effects are compared with each other, i.e. explosion, heat, shock wave (blast), ionizing radiation, and fallout. RESULTS: In the center of the explosion of a nuclear bomb, the temperature rises to 100Mio degrees C, this induces damaging heat radiation and shock wave. In the largest imaginable accident in a nuclear power plant and in the conventional explosion of a dirty bomb, the temperature may rise up to 3000 degrees C, heat radiation and blast are limited to a short distance. In nuclear power plants, explosions due to oxyhydrogen gas or steam may occur. In nuclear explosions the dispersed radioactive material (fall out) consists mainly of isotopes with short half-life, in nuclear power plants and in dirty bomb attacks with longer half-life. The amount of fall out is comparable in nuclear bomb explosions with that in the largest imaginable accident in a nuclear power plant, it is smaller in attacks with dirty bombs. An explosion in a nuclear power plant even in the largest imaginable accident is not a nuclear explosion. In Hiroshima and Nagasaki, there were 200,000 victims nearly all by heat and blast, some 300 died by ionizing radiation. In Chernobyl, there have been less than 100 victims due to ionizing radiation up till now. A dirty bomb kills possibly with the explosion of conventional explosive, the dispersed radioactive material may damage individuals. The incorporation of irradiating substances may kill and be difficult to detect (Litvinenko). A new form of (government supported) terrorism/crime appears possible. CONCLUSION: The differences are important between a nuclear weapon explosion, the largest imaginable accident in a nuclear power plant, and an attack with a dirty bomb. Nuclear weapons kill by heat and blast; in the largest imaginable accident in a nuclear power plant, they are less strong and limited to the plant; an attack with a dirty bomb is as life threatening as an ("ordinary") bomb attack, dispersed radiating material may be a risk for individuals.     

Sleep extension: getting as much extra sleep as possible

Nearly all people, whether they consider themselves sleep deprived or not, can initially obtain extra sleep. However, as accumulating extra sleep reduces carryover sleep debt, a point is reached where it is no longer possible to obtain extra sleep. If there were a practical method to make a precise measurement of a person's daily sleep requirement, it may be possible to show that most individuals are carrying a very large sleep debt. Several observations and studies demonstrate that almost everyone is sleep deprived and carries some amount of sleep debt. How long such an indebtedness will persist without change if no extra sleep is obtained is not known.