棒状链霉菌中lat基因的置换与克拉维酸的选择性生产

目的提高棒状链霉菌的克拉维酸生产能力 ,去除副产物头霉素C。方法将安普霉素抗性基因片段插入到 4 7kb的lat pcbAB基因片段中 ,采用接合转移方法对棒状链霉菌中头霉素C生物合成的关键基因lat基因进行了置换。结果与结论经PCR验证 ,染色体上正常的lat pcbAB基因被插入失活的基因所替代。对重组菌株的发酵产物进行HPLC检测 ,发现所有的重组菌株均不再合成头霉素C ,并且重组菌株C35 85 lat ::apr、C2 5 1 lat::apr和C16 6 lat::apr的克拉维酸产量较出发菌株分别提高了 2 6 7 6 8%、4 3 6 9%和 35 0 5 %。结果表明基因插入失活是去除多余组分 ,提高目标组分产量的可行途径     

海藻糖在气管低温保存中的保护机制

目的探讨海藻糖在气管低温保存中的保护作用和机制。方法新鲜配制4组保存液，其中：Ⅰ组LPD；Ⅱ组LPD 10％DMSO；Ⅲ组LPD 0．15M海藻糖；Ⅳ组LPD 10％DMSO 0．15M海藻糖。切取SD大鼠气管后立即分别放入含上述4种溶液的冻存管，在程序降温仪降至-80℃后投入液氮中保存。20d后对气管标本进行HE染色和Bcl-2、Pax蛋白检测(免疫组化)，并将其异位移植到Wistar大鼠腹腔，15d后取出移植气管，观察组织学变化。结果4种保存液低温保存气管20d后，Ⅲ组和Ⅳ组气管结构完整，软骨细胞Pax蛋白表达较低，尤其Ⅳ组保存效果最好，同种异体异位移植后生长良好。各组Bcl-2蛋白表达无明显区别。结论在气管低温保存中海藻糖的保护作用主要是通过对软骨细胞的保护实现的，抑制软骨细胞Pax基因的表达是其中的保护机制之一。海藻糖和DMSO合用保护作用更好。     

喉癌组织中BcL-2和Bax基因的表达

目的探讨喉癌组织BcL2和Bax基因蛋白表达与喉癌发生、发展的关系。方法采用免疫组化SP法测定15例正常人声带组织和73例喉癌组织标本中BcL2和Bax基因蛋白表达。结果喉癌组织中BcL2基因蛋白表达阳性检出率452%,喉癌组织中Bax基因蛋白表达阳性检出率603%,差异有显著意义(P<005)。喉癌组织中BcL2和Bax基因蛋白的表达呈明显的负相关关系(r=-071,P<005)。结论喉癌组织中BcL2和Bax基因蛋白表达的失调可能与喉癌的发生、发展有关。     

幽门螺杆菌的耐药分析及对Hp根除的影响

目的探讨幽门螺杆菌(Hp)对常用抗菌药的耐药性及对Hp根除的影响,给临床提供合理用药的科学依据.方法采用用改良布氏活性炭培养基(平板)在微需氧环境中培养幽门螺杆菌,并利用琼脂稀释法行幽门螺杆菌的药敏试验.并用三联疗法对62例消化性溃疡进行Hp根除治疗.结果从112例消化性溃疡患者胃黏膜中培养出Hp 62株,对阿莫西林、四环素、克拉霉素、甲硝唑、替硝唑、呋喃唑酮的耐药率分别为1.61%、3.23%、11.2%、58.1%、3.23%、0%.7d根除治疗对Hp的总根除率为:对甲硝唑及克拉霉素敏感株根除率为91.5%,对甲硝唑耐药株根除率为52%,对克拉霉素耐药株根除率为0(P＞0.05).结论阿莫西林、替硝唑、四环素、呋喃唑酮的耐药率较低;而甲硝唑和克拉霉素耐药率较高.其耐药影响Hp根除.     

Differential expression of CYP1A, 2B, and 3A genes in the F344 rat following exposure to a polybrominated diphenyl ether mixture or individual components.

Polybrominated diphenyl ethers (PBDEs), used as flame retardants, have been detected in the environment and in mammalian tissues and fluids. Evidence indicates that PBDE mixtures induce CYPs through aryl hydrocarbon receptor (AhR)-dependent and -independent pathways. The present work has investigated the effects of individual components of a commercial PBDE mixture (DE71) on expression of CYP1A1, a biomarker for activation of the AhR (dioxin-like), and CYP2B and CYP3A, biomarkers for activation of the constitutive androstane and pregnanexreceptors (CAR and PXR), respectively, in the rat. Male F344 rats were dosed orally on three consecutive days with either DE71, PBDE components, 2,2',4,4'-tetraBDE (BDE47), 2,2',4,4',5-pentaBDE (BDE99), 2,2',4,4',5,5'-hexaBDE (BDE153), representative polybrominated dibenzofurans (PBDFs) present in DE71, or reference PCBs. Differential expression of target genes was determined in liver 24 h after the last dose. Quantitative PCR analysis indicated up-regulation of CYP1A1 by DE71; however, the response was weak compared to that for dioxin-like PCB126. Individual PBDE components of DE71 up-regulated CYP1A1 only at the highest administered dose (100 micromol/kg/day). Representative PBDFs efficiently up-regulated CYP1A1; therefore, they, along with other PBDFs and polybrominated dibenzodioxins detected in DE71 and individual PBDE components, may be responsible for most, if not all, dioxin-like properties previously observed for PBDEs. Conversely, PBDEs appear capable of up-regulating CYP2B and CYP3A in rats at doses similar to that for non-dioxin-like PCB153. These results indicate that in vivo PBDE-mediated toxicity would be better categorized by AhR-independent mechanisms, rather than the well-characterized AhR-dependent mechanism associated with exposure to dioxin-like chemicals.     

Detection of thyroid system-disrupting chemicals using in vitro and in vivo screening assays in Xenopus laevis.

We developed a thyroid hormone (TH) inducible primary screening assay for the identification and assessment of man-made chemicals that interfere with the TH-signalling pathway within target cells. The assay was developed in a Xenopus laevis cell line that was transduced with a self-inactivating (SIN) lentivirus vector (LV) containing a luciferase gene. The luciferase activation in this cell line was TH-specific: 3,3',5-L-triiodothyronine (T(3)) > 3,3'5-L-triiodothyroacetic acid (Triac) > 3,3',5-D-triiodothyronine (D-T(3)), > L-thyroxine (T(4)) > 3,3',5'-L-triiodothyronine (rT(3)). The application of the ligand-dependent luciferase assay for screening for thyroid system-disrupting chemicals revealed that three phthalates (dicyclohexyl phthalate, n-butylbenzyl phthalate, and di-n-butyl phthalate), two herbicides (ioxynil and pentachlorophenol) and a miticide (dicofol) had 3,3',5-L-triiodothyronine- T(3)- antagonist activity at concentrations ranging from 10(-6) to 10(-5) M. These chemicals also inhibited the expression of the endogenous primary T(3)-response TH nuclear receptor beta (TRbeta) gene. The inhibitory characteristics of these chemicals were similar for both assays performed, although the assay for T(3)-dependent activation of TRbeta gene was more sensitive than the luciferase assay. These results indicate that the luciferase assay was a rapid method with a small intra-assay variation for the primary screening of thyroid system-disrupting chemicals. Of the six chemicals, only n-butylbenzyl phthalate and pentachlorophenol exhibited T(3)-antagonist activity in an in vivo metamorphosis-based assay. It should be noted that chemicals elicited thyroid system-disrupting activity in the luciferase assay did not always interfere with the thyroid system in vivo.     

胃癌中医证型与胃癌转移相关基因E-cadherin的关系研究

目的:从基因蛋白表达上探索胃癌患者中医证的本质.方法:将收集到的术前胃癌患者病例资料按中医辨证分型标准确定其证型归属;用免疫组化EnVision二步法检测术后胃癌肿瘤标本中E-cadherin基因蛋白表达情况.结果:E-cadherin在100例胃癌患者中的阳性表达率为90%,证型间表达差异存在显著性(P<0.01);进一步两两比较示,痰湿凝结型、气血双亏型与脾胃虚寒型之间无明显差异,表达较高;瘀毒内阻型与肝胃不和型无明显差异,表达较低.结论:瘀毒内阻型与肝胃不和型胃癌患者的E-cadherin表达偏低,此两种证型肿瘤转移形成的途径可能与E-cadherin,即与肿瘤细胞间同质性黏附力降低相关.     

雌激素调节蛋白PS2乳腺浸润性导管癌表达及其临床意义

[目的]探讨雌激素调节蛋白(PS2)在乳腺浸润性导管癌中的表达及其与临床病理因素间的关系。[方法]采用免疫组化方法检测155例乳腺浸润性导管癌中ER、PR和PS2的表达。[结果]全组PS2表达阳性率38.1%。在ER阳性和阴性病例中,PS2阳性率分别为48.6%和29.4%(χ2=5.977,P<0.05);在PR阳性和阴性组中,PS2阳性率分别为50.8%和28.9%(χ2=7.664,P<0.01)。PS2的表达与病人年龄、月经状况、肿瘤大小无关(P>0.05);而与腋淋巴结状况(P<0.001)、临床分期(P<0.05)有关。此外,PS2的表达在民族间也存在一定差异,但无统计学意义。[结论]乳腺浸润性导管癌中PS2的表达与ER、PR呈正相关关系,并与腋淋巴结状况和临床分期有关。PS2可以作为预测乳腺癌预后的一项重要指标。     

nm23-H1基因表达与鼻咽癌的早发转移

目的探讨nm23-H1基因产物的表达与鼻咽癌早发转移的关系.方法应用免疫组化S-P法对95例鼻咽癌组织蜡块进行nm23-H1检测.结果nm23-H1的阳性表达率为47.4%(45/95),早发转移组nm23-H1阳性率(26.7%)低于无转移组(60.0%),差异有统计学意义(P＜0.05).nm23-H1表达与临床分期无关.结论nm23-H1阴性表达与鼻咽癌早发转移有关,nm23-H1的表达水平可能是预测中晚期鼻咽癌远处转移的一个重要的生物学指标.     

胃癌中p27~(Kip1)、p53表达与其浸润、转移和预后的关系(英文)

目的研究胃癌组织中p27~(Kipl)和 p53的表达与胃癌浸润、转移和预后的关系。方法用免疫组化(二步法)检测100例胃癌组织中的 p27~(Kipl)蛋白和 p53蛋白的表达。结果 100例胃癌组织中 p27~(Kipl)和 p53蛋白阳性表达率分别为44%和49%。在胃癌深部浸润组、淋巴结转移组和5年内死亡组中p27~(kipl)呈显著低表达(P<0.05);在胃癌淋巴结转移组和5年内死亡组中 p53呈显著高表达(P<0.05)。经单变量分析结果显示p27~(Kipl)高表达组5年生存率为70.59%,显著高于低表达组54.55%和阴性组26%;p53高表达组5年生存率为19.23%,显著低于低表达组43.75%和阴性组53.19%。多变量 Cox 回归模型分析显示p27~(Kipl)、p53均是独立的预后指标,但 p27~(Kipt)表达对患者预后的相对危险度(RR=3.06)显著大于 p53表达的相对危险度(RR=2.33,P<0.01)。结论 p27~(Kipl)低表达与 p53高表达的癌细胞常更能浸润与转移,使患者生存率明显降低。p27~(kipl)和 p53是胃癌预后的独立指标,其中 p27~(Kipl)表达评估胃癌预后的作用优于 p53。