罗汉果对雄性小鼠骨髓微核和精子形态的影响

背景：对罗汉果的遗传毒性进行研究,可为其安全使用提供实验依据。目的：观察罗汉果水提液对雄性小鼠骨髓细胞微核率和附睾精子畸形率的影响,了解其是否有遗传毒性。方法：按罗汉果水提液最大使用剂量（3g/mL）和最大灌胃容量（20mL/kg）灌胃小鼠,观察罗汉果水提液的急性毒性。将雄性昆明小鼠随机分为5组,分别灌胃给予30,15,7.5g/kg的罗汉果水煎液、蒸馏水,连续5d;或腹腔注射40mg/kg环磷酰胺。于灌胃第5天,采用骨髓嗜多染红细胞微核试验计算小鼠的骨髓微核率。于首次灌胃后第35天,观察小鼠精子畸形率。结果与结论：罗汉果水提液对昆明小鼠的经口急性毒性最大耐受剂量大于120g/kg。罗汉果水提液30,15,7.5g/kg灌胃后,小鼠的骨髓微核率、精子畸形率与正常小鼠无差异（P〉0.05）,均明显低于环磷酰胺诱发的骨髓微核率和精子畸形率（P〈0.05）。说明罗汉果水提液对成年雄性小鼠无明显遗传毒性。     

姜蒜精华素安全性实验研究

目的对姜蒜精华素片进行安全性实验研究。方法依据《保健食品检验与评价技术规范》(2003年版)进行急性毒性试验、Ames试验、小鼠骨髓嗜多染红细胞微核试验、小鼠精子畸形试验、30d喂养试验。结果小鼠的急性毒性MTD均大于15g/KgBW;Ames试验未呈现遗传毒性;小鼠骨髓嗜多染红细胞微核试验阴性;30d喂养试验未呈现毒性。结论在本实验条件下姜蒜精华素片无毒属安全性食品。     

N,O-羧甲基壳聚糖对小白鼠精子畸形的影响

目的:观察能明显促进禽类等动物的生长发育,改善肉质的新型饲料添加剂N,O-羧甲基壳聚糖对昆明种小白鼠精子畸形的影响,分析其应用在畜牧生产中的安全性。方法:实验于2005-06-22/2005-08-06于南京农业大学动物医学院药理组实验室完成。挑选体质量25～28g的小鼠50只,以随机数字表法分为生理盐水组、环磷酰胺组、N,O-羧甲基壳聚糖(南京龙源天然多酚合成厂提供,商品名为毕罗喜,质量浓度为105g/kg)2,4,8g/kg剂量组,每组10只。N,O-羧甲基壳聚糖2,4,8g/kg剂量组分别给予相应剂量的N,O-羧甲基壳聚糖,溶于1mL生理盐水,2,4g/kg剂量1次灌服,8g/kg剂量分2次灌服,每次间隔约3h;生理盐水组给予生理盐水1mL;环磷酰胺组给予环磷酰胺0.04g/kg,溶于1mL生理盐水。给药前禁食10h,不禁水。连续灌胃5d,给药后30d麻醉下处死,取两侧附睾按Wyrobek方法涂片,观察小白鼠精子畸形状况。评估标准参照农业部兽药评审委员会办公室编写的兽药试验技术规范汇编(2001年)。评估内容参照沈建忠主编的动物毒理学(中国农业出版社,2002年),包括各种畸形的精子形态:不定形、胖头、香蕉头、无钩、双头(多头)和双尾(多尾)等,及其分类计数。每组随机选取5只小鼠,计算总畸形率。精子畸形率(%)=畸形精子总数/检查精子总数×100。结果:最终25只小鼠进入结果分析,每组5只。①环磷酰胺组的精子畸形率远高于生理盐水组和N,O-羧甲基壳聚糖2,4,8g/kg剂量组(6.10%,2.48%,2.46%,2.64%,2.78%,P<0.01);N,O-羧甲基壳聚糖2,4,8g/kg剂量组与生理盐水组比较,差异无显著性意义(P>0.05),且各剂量组之间差异也没有显著性意义(P>0.05)。②各组精子畸形主要表现为头部或尾部异常。以无定形和胖头居多,占35.48%(292/823)和29.28%(241/823);其次是无钩形及香焦形多见,占19.68%(162/823)和13.49%(111/823);偶尔可见双头双尾形,只占2.07%。结论:N,O-羧甲基壳聚糖精子畸形试验结果呈阴性,说明其对雄性生殖细胞没有明显的遗传毒性。     

酸性氧化电位水毒性的试验研究

为了解酸性氧化电位水消毒使用的安全性,采用动物试验法对其进行了毒理学评价。结果,酸性氧化电位水对大、小鼠急性经口毒性LD50均大于10000 mg/kg(体重),属实际无毒级。皮肤和眼刺激性试验结果刺激强度积分为0分,属无刺激性。小鼠骨髓嗜多染红细胞微核试验和精子畸形试验结果均为阴性,无致微核和无致精子畸形作用。亚急性毒性试验各剂量组试验动物生长发育和处死动物解剖检查各项指标未发现明显改变;雌性动物3个剂量组天冬转氨酶活性均显著升高,高剂量组动物白细胞数显著下降;雄性动物高剂量组肝脏脏器系数比对照组显著降低,血清白蛋白含量显著上升,这些指标仍在本实验室正常范围内;但血清天冬转氨酶活性增高异常。结论,酸性氧化电位水急性毒性属实际无毒级,对皮肤和眼睛无刺激性,无致微核和精子畸形作用,未显示明显亚急性毒性。     

阳离子表面活性剂与戊二醛复合消毒剂毒性评价

目的了解一种阳离子表面活性剂与戊二醛复合消毒剂的安全性,评价其毒性。方法采用急性经口毒性试验、皮肤刺激试验、急性眼刺激试验、小鼠骨髓嗜多染红细胞微核试验、小鼠精子畸形试验等评估复合消毒剂的安全性。结果该复合消毒剂原液急性经口毒性试验LD505 000 mg/kg;对完整皮肤和眼无刺激性;各剂量组小鼠骨髓嗜多染红细胞微核率和精子畸形率与阴性对照相比无显著性差异,与阳性对照差异显著。结论该复合消毒剂无毒性,安全性良好。     

聚甲基丙烯酸甲酯／二氧化硅纳米义齿树脂材料遗传毒性的小鼠骨髓微核试验评价

背景:甲基丙烯酸甲酯/二氧化硅纳米复合材料已通过了包括细胞毒性试验、溶血试验、急性全身毒性试验、口腔黏膜刺激试验、皮肤致敏反应试验的生物安全性检测.目的:采用小鼠骨髓微核试验进一步探讨聚甲基丙烯酸甲酯/二氧化硅纳米义齿树脂对细胞遗传物质可能产生的损伤作用.设计、时间及地点:随机对照动物实验,于2007-11/2008-01在天津医科大学公共卫生学院毒埋实验室完成.材料:SPF级昆明小白鼠50只,随机分为5组:阴性对照组,低、中、高剂量混悬液组,阳性对照组,10只/组.聚甲基丙烯酸甲酯/二氧化硅纳米义齿树脂由天津医科大学口腔医院制备.方法:将聚甲基丙烯酸甲酯/二氧化硅纳米义齿树脂材料粉碎成细小颗粒,过筛后加入生理盐水形成混悬液,质量浓度为0.3 g/mL.阴性对照组灌胃生理盐水:低、中、高剂量混悬液组分别按15.0,7.5,3.75 g/kg灌胃混悬液进行染毒;阳性对照组腹腔注射环磷酰胺,按40 mg/kg给药.第1次染毒后24 h再次染毒,末次染毒后6 h取材,取胸骨骨髓加入胎生血清制备涂片,Giemsa染色.主要观察指标:每只小鼠骨髓涂片计数1 000个嗜多染红细胞,记录含微核的嗜多染红细胞数,求出微核率.结果;阴性对照组微核率为0.248%,阳性对照组为4.384%,低、中、高剂量混悬液组微核率分别为0.150%,0.254%,0.277%.与阴性对照组比较,低、中、高剂量混悬液组微核率无明显变化(P0.05),阳性对照组微核率显著升高(P<0.01).结论:聚甲基丙烯酸甲酯,二氧化硅纳米义齿树脂对小鼠细胞染色体无明显的诱变效应,具有较好的生物安全性.     

N,O-羧甲基壳聚糖对小白鼠精子畸形的影响

目的：观察能明显促进禽类等动物的生长发育。改善肉质的新型饲料添加剂N，O-羧甲基壳聚糖对昆明种小白鼠精子畸形的影响，分析其应用在畜牧生产中的安全性。 方法：实验于2005—06—22／2005—08—06于南京农业大学动物医学院药理组实验室完成。挑选体质量25～28g的小鼠50只，以随机数字表法分为生理盐水组、环磷酰胺组、N，O-羧甲基壳聚糖（南京龙源天然多酚合成厂提供，商品名为毕罗喜，质量浓度为105g／kg）2，4，8g／kg剂量组，每组10只。N，O-羧甲基壳聚糖2，4，8g／kg剂量组分别给予相应剂量的N，O-羧甲基壳聚糖，溶于1mL生理盐水，2，4g／kg剂量1次灌服，8g／kg剂量分2次灌服。每次间隔约3h；生理盐水组给予生理盐水1mL；环磷酰胺组给予环磷酰胺0．04g／kg，溶于1mL生理盐水。给药前禁食10h，不禁水。连续灌胃5d，给药后30d麻醉下处死，取两侧附睾按Wyrobek方法涂片。观察小白鼠精子畸形状况。评估标准参照农业部兽药评审委员会办公室编写的兽药试验技术规范汇编（2001年）。评估内容参照沈建忠主编的动物毒理学（中国农业出版社，2002年），包括各种畸形的精子形态：不定形、胖头、香蕉头、无钩、双头（多头）和双尾（多尾）等，及其分类计数。每组随机选取5只小鼠，计算总畸形率。精子畸形率（％）=畸形精子总数／检查精子总数&;#215;100。 结果：最终25只小鼠进入结果分析，每组5只。①环磷酰胺组的精子畸形率远高于生理盐水组和N，O-羧甲基壳聚糖2，4，8s／kg剂量组（6．10％，2．48％，2．46％，2．64％，2．78％，P〈0．01）；N，O-羧甲基壳聚糖2，4，8g／kg剂量组与生理盐水组比较，差异无显著性意义（P〉0．05），且各剂量组之间差异也没有显著性意义（P〉0．05）。②各组精子畸形主要表现为头部或尾部异常。以无定形和胖头居多，占35．48％（292／823）和29．28％（241／823）；其次是无钩形及香焦形多见，占19．68％（162／823）和13．49％（111／823）；偶尔可见双头双尾形，只占2.07％。 结论：N，O-羧甲基壳聚糖精子畸形试验结果呈阴性，说明其对雄性生殖细胞没有明显的遗传毒性。     

对一种强化碱性戊二醛消毒剂的毒理学评价

为了解四环牌强化碱性戊二醛的安全性,进行了急性经口毒性、蓄积毒性、皮肤变态反应、小鼠骨髓嗜多染红细胞微核和精子畸形试验。结果,该剂对小鼠经口LD50为6329mg/kg（体重）,蓄积系数K>5;豚鼠皮肤变态反应试验未出现过敏反应;试验用戊二醛剂量诱导PCE微核细胞率与阴性对照组差异无统计学意义（P>0.05）,对小鼠精子畸形发生率无影响。因此,在本实验条件下,强化碱性戊二醛为实际无毒、弱蓄积毒性。极轻致敏性物质,没有致突变作用。     

汰可分手消毒液毒性评价

为了解汰可分手消毒液的安全性,对其进行了急性经口毒性、蓄积毒性、皮肤刺激性、小鼠骨髓嗜多染红细胞微核试验和精子畸形试验。结果,汰可分手消毒液对雌、雄小鼠急性经口毒性LD50均大于5000 mg/kg体重;对小鼠蓄积毒性蓄积系数K>5;对家兔皮肤刺激指数<0.4,无皮肤刺激性;对小鼠骨髓嗜多染红细胞无致微核作用;对小鼠精子无致畸作用。因此,在本实验条件下,该消毒液为实际无毒物质,对皮肤无刺激性,没有致突变作用。     

二氯甲烷不同途径染毒对小鼠骨髓细胞微核率的影响

目的 通过比较不同途径染毒的小鼠骨髓细胞微核实验,探讨二氯甲烷(DCM)的遗传毒性.方法 通过连续染毒5天的静式吸入和灌胃给予DCM,分别于末次染毒后6 h和24 h取股骨骨髓常规制片.结果 在经呼吸道染毒的小鼠骨髓细胞微核试验中,高浓度组(16 mg/L)小鼠骨髓细胞微核率与阴性对照组比较有极显著性差异(P＜0.01),中浓度组(8 mg/L)和低浓度组(4 mg/L)小鼠骨髓细胞微核率与阴性对照组比较也有显著性差异(P＜0.05).在剂量4～16 mg/L之间,小鼠骨髓微核率由4.0‰上升至15.0‰,呈明显的剂量反应关系.在经灌胃染毒的小鼠骨髓细胞微核试验中,随着剂量的增加,小鼠骨髓细胞微核率也有不同程度的增加,与阴性对照组比较有显著性差异.末次染毒后6h采样结果 与24 h采样无显著性差异(P＞0.05).结论 经呼吸道和消化道给予一定剂量的DCM均能明显增加小鼠骨髓嗜多染红细胞(PCE)的微核率,且微核率的增加并没有性别差异.     

Anti-influenza virus activity of propolis in vitro and its efficacy against influenza infection in mice

BACKGROUND: Propolis has been used worldwide as a dietary supplement to maintain and improve human health. We examined whether ethanol extracts of Brazilian propolis exhibit antiviral activity against influenza virus in vitro and in vivo. METHODS: Among 13 ethanol extracts screened in a plaque reduction assay, four showed anti-influenza virus activity. The anti-influenza efficacy of the four extracts was further examined in a murine influenza virus infection model. The mice were infected intranasally with influenza virus, and the four extracts were orally administered at 10 mg/kg three times daily for seven successive days after infection. RESULTS: In this infection model, only one extract, AF-08, was significantly effective at 10 mg/kg in reducing the body weight loss of infected mice. The doses of 2 and 10 mg/kg were also effective in prolonging the survival times of infected mice significantly, but 0.4 mg/kg was not. The anti-influenza efficacy of AF-08 at 10 mg/kg was confirmed in a dose-dependent manner in mice. AF-08 at 10 mg/kg significantly reduced virus yields in the bronchoalveolar lavage fluids of lungs in infected mice as compared with the control. The reduction of virus yields by AF-08 at 10 mg/kg significantly corresponded to those induced by oseltamivir at 1 mg/kg twice daily from day 1 to day 4 after infection. CONCLUSION: The Brazilian propolis AF-08 was indicated to possess anti-influenza virus activity and to ameliorate influenza symptoms in mice. AF-08 may be a possible candidate for an anti-influenza dietary supplement for humans.     

小鼠灌胃赤芍单味药和桃红四物汤后体内芍药苷的水平比较

背景:桃红四物汤由桃仁、红花、当归、赤芍、生地、川芎组成。芍药苷为赤芍单味药和中药复方桃红四物汤的主要有效成分之一,具有活血化瘀,抗急性心肌缺血的作用。目的:比较小鼠灌胃赤芍和桃红四物汤后血清中芍药苷的质量浓度。设计:随机对比观察。单位:河北北方学院药学系,河北北方学院基础医学部。材料:实验于2005-02/06在河北北方学院药学系第一实验室完成。选用18～22g昆明种小鼠80只,雌雄兼有,清洁级,购自北京中国科学院遗传与发育生物学研究所实验动物中心。6种中药桃仁、红花、当归、赤芍、生地、川芎均购自张家口中医研究院。方法:①取8只小鼠空腹12h后分离空白血清,于空白血清中加芍药苷对照品溶液,乙腈沉淀蛋白,离心分离,取上清液20μL,得回归方程。②将72只昆明种小鼠按随机数字表法分为赤芍组和桃红四物汤组,每组36只。空腹12h后,分别灌胃赤芍提取物及桃红四物汤提取物,以芍药苷计300mg/kg,灌胃后于15,30,60,90,120,180min取血1mL(每组每个时间点各6只),制备血清样品。比较小鼠灌胃赤芍提取物与桃红四物汤提取物后血清中芍药苷达峰时间和达峰浓度的差异。高效液相色谱法测定芍药苷含量,色谱条件为:色谱柱YWG-C18(250×4.6mm,10μm),流动相甲醇-0.05mol/LKH2PO4(38∶62);流速1.0mL/min;检测波长230nm;柱温25℃。主要观察指标:赤芍和桃红四物汤在小鼠血清中芍药苷的质量浓度。结果:72只小鼠用于赤芍和桃红四物汤实验,全部进入结果分析,无脱失。①色谱分离结果:芍药苷与血清中其他成分能很好分离,在5.40～646.0μg/mL范围内线性关系良好,平均回收率为93.6%,最低监测浓度1.08mg/L。②灌胃不同时间两组小鼠血清中芍药苷的质量浓度比较:赤芍组和桃红四物汤组分别在灌胃60,30min后达峰值(46.82±5.29),(36.27±5.72)mg/L,桃红四物汤组的峰值浓度低于赤芍组(P<0.01)。结论:复方配伍后,血清中芍药苷浓度明显降低,提示配伍组方后其他化学成分可能促进了芍药苷的代谢转化,从而降低了血清中原形药的浓度。     

The effects of plastic bag extracts prepared in either mouse serum or phosphate-buffered saline with ethanol on mouse splenic cells

Chemicals leached from plastic blood bags are potentially immunogenic when introduced parenterally into humans. The experiments reported here represent an attempt to sensitize B6C3F1 mice to parenteral injections of solutions used to extract potentially immunogenic material from plastic blood bags. Mice were given intraperitoneal injections: blood bag extracts prepared from phosphate-buffered saline and ethanol; mouse red cells stored in extract solution; or blood bag extracts prepared from mouse serum. None elicited a significant in vitro immunologic reaction as determined by 3H-thymidine or 3H-leucine uptake into spleen cells. In contrast, intraperitoneal injections in mice of large amounts (0.5 ml) of the phosphate-buffered saline and ethanol extracts decreased spleen cellularity to 59 percent of the control value and reduced spleen cell blastogenic activity in vitro. When solutions of either mouse serum extract or mouse cells stored in extract were given intraperitoneally to mice, no spleen toxicity or increased blastogenic activity was observed. In addition, the extracts obtained from plastic blood bags by using either allogenic serum or buffered saline and ethanol did not elicit an immunologic response when they were administered parenterally to mice.     

Comparison of the mechanism of isoproterenol-stimulated glycogenolysis in skeletal muscle of normal and phosphorylase kinase-deficient mice (I strain).

Diaphragm extracts from mice with the phosphorylase kinase deficiency mutation (I strain) have only 3.7% of the phosphorylase kinase activity of muscle extracts of the control strain (C57BL). Nevertheless, previous studies have shown that isoproterenol-stimulated glycogenolysis in I strain diaphragm muscle at a rate 57% (average relative response at 10 isoproterenol concentrations) of that of C57BL (GROSS, S.R., MAYER, S.E. and LONGSHORE, M.A.: J. Pharmacol. Exp. Ther. 198: 523-538, 1976). The present studies were initiated to compare the mechanism of isoproterenol-stimulated glycogenolysis in I and C57BL diaphragms. Isoproterenol was found to stimulate phosphorylase b to a conversion with an EC50 of 8 nM in muscles from mice of either strain, and the maximum increase in phosphorylase alpha activity in I diaphragms was 23% of that in C57BL diaphragms. Moreover, the initial rate of increase in phosphorylase alpha activity in I diaphragms incubated with 40 nM isoproterenol was 24% of that in C57BL muscles. The isoproterenol-stimulated increases in cyclic AMP content in diaphragms of the two strains were the same. Incubation of I diaphragms with isoproterenol did not significantly increase the concentrations of AMP, IMP or inorganic phosphate, activators of phosphorylase beta activity, nor was there a decrease in ATP and glucose 6-phosphate content, allosteric inhibitors of phosphorylase beta activity. Thus, phosphorylase alpha formation is the principal, if not only, catalyst of isoproterenol-stimulated glycogenolysis in skeletal muscle of phosphorylase kinase-deficient mice, and no evidence was obtained indicating that allosteric regulation of phosphorylase beta activity is part of the mechanism.     

Molecular dissection of hepatitis C virus expression

OBJECTIVE: The 5' untranslated region (5' UTR) of the hepatitis C virus genome is thought to be important for the control of viral gene expression and a likely target for therapeutic interception. A functional role of this viral gene segment was analyzed both in vivo and in vitro. METHODS: Transgenic mice carrying a reporter gene that contains the complete 5' UTR sequence were made. Cellular protein(s) which associate with the 5' UTR were analyzed by gel shift analysis and a following affinity purification. RESULTS: Transgenic mice revealed protein accumulation only in periportal hepatocytes around the portal triad and not in perivenous hepatocytes around the central vein. Gel shift analysis using mouse liver extracts provides further evidence that trans-acting proteins, which recognize a specific cis-acting element with the 5' UTR (an apparent stemmed structure formed by two noncontiguous RNA sequences), are present in adult mice but not in young mice. A similar 5' UTR RNA-protein complex was also detected with human liver extracts. CONCLUSION: The presence of cellular factor(s) which allow HCV 5' UTR to express in tissue and differentiation state-specific manner was suggested.     

RESPONSES TO IMMUNIZATION IN THE THYMUS OF THE ADULT MOUSE

The rate of synthesis of RNA in the thymus glands of adult mice increased after immunization with sheep red blood cells (SRBC). The specific activity of some fractions of RNA, separated first by density gradient centrifugation and then by polyacrylamide gel electrophoresis, was 16-fold higher on day 3 after immunization than control mice not injected. RNA synthesis in the thymus was inhibited by rabbit anti-mouse thymus serum, injected along with antigen. A material was found in RNA extracts from the thymus glands of mice immunized with SRBC which converted a small proportion of either spleen cells or peritoneal cells from nonimmunized mice to form sheep cell hemolysins. Neither extracts from the glands of nonimmunized mice nor the livers of immunized mice were active. Extracts from the thymus glands of mice immunized with rabbit red blood cells (RRBC) were inactive and activity was destroyed by ribonudease. The residual antigen content was not determined. Biologically active extracts from the thymus had a different electrophoretic mobility from active extracts from the spleen.     

Acute and sub-acute toxicity study of Clerodendrum inerme,Jasminum mesnyi Hance and Callistemon citrinus

ObjectiveTo study acute and sub-acute toxicity study of Clerodendrum inerme (C. inerme), Jasminum mesnyi (J. mesnyi) Hance and Callistemon citrinus (C. citrinus).MethodsThe acute toxicity test was conducted in Swiss albino mice. The extracts of C. inerme, J. mesnyi Hance and C. citrinus was administered in single dose of 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0 g/kg and observed for behavioral changes and mortality, if any. In sub-acute toxicity study, Wistar rats of either sex were administered 1/5th of the maximum tolerated dose, p.o. for 4 weeks. Rats were observed weekly for any change in their body weight, food and water intake during 28 d of the treatment. At the end of 28 d, blood samples of the rats were collected for hematological and biochemical study.ResultsIn acute toxicity study, all four extracts of three plants were found to be well tolerated up to the dose of 2 000 mg/kg. These produced neither mortality nor any change in the behavior in mice. In sub-acute toxicity study, all four extracts of three plants at the LD₅₀ dose level did not produce any significant alteration in hematological and biochemical parameters in rats.ConclusionsThe results demonstrated that there is a wide margin of safety for the therapeutic use of each of the four extracts of three plants. The findings also corroborated the traditional use of these extracts.     

内毒素诱导性基因启动子结合蛋白的筛选新方法及其应用

目的建立研究DNA-蛋白质相互作用的新方法。方法选择6只SPF级BALB／c小鼠,模型组经尾静脉注射脂多糖（LPS）25mg／kg,使平均动脉压（MAP）降至40mmHg（1mmHg=0．133kPa）造成内毒素休克,然后迅速处死,正常对照组同期处死,取肝脏组织。利用生物素一链亲和素系统结合磁珠分离技术筛选内毒素诱导基因（LIG）启动子的结合蛋白。用聚合酶链反应（PCR）扩增末端带生物素标记的LIG启动子探针,提取动物肝脏组织胞核蛋白,与制备的LIG启动子探针进行孵育,再以标记有链亲和素的磁珠分离LIG启动子-蛋白反应复合物,使用不同浓度NaCl洗脱结合的蛋白,使用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS—PAGE）分离样品蛋白,并对凝胶进行银染显色,比较模型组与正常对照组的差异条带。结果两组胞核蛋白中共观察到15条差异条带。分析差异条带显示,与正常对照组比较,在低亲和力作用水平,LPS作用后有4个蛋白开始与LIG启动子作用力增强,而有1个蛋白则同启动子的相互作用减弱;在DNA-蛋白质高亲和力作用水平,则有9个蛋白因LPS刺激而同DNA的结合力增强,有1个蛋白同启动子的相互作用消失。结论成功建立了生物素-链亲和素结合磁珠分离技术的新方法,为研究DNA-蛋白质相互作用开拓了新思路,并从“转录调控组学”角度深入理解基因表达调控机制奠定了基础。     

A FACTOR FROM NORMAL TISSUES INHIBITING TUMOR GROWTH

Extracts of desiccated embryo skin and placenta have been found to exert a definite retarding action on the growth of two transplantable carcinomas of mice, but they were without effect on sarcomas. In tests involving some 828 inoculations of the tumor cells and the extracts, complete suppression of growth occurred in from 55 to 71 per cent of instances, as compared with 21 to 27 per cent in the controls, and where growth was not completely suppressed some retardation was found in practically every instance. To judge from findings in rabbits the inhibitor is not demonstrable in the placenta until the beginning of the second third of pregnancy, reaches its maximum by the last third, but disappears about 2 or 3 days before term. Extracts of fresh placenta are without effect, and no very definite inhibition was noted in extracts of a variety of other desiccated or fresh tissues. The conclusions here reported are based on the results of over 3800 inoculations.