Na+/Ca2+‐exchanger‐mediated Mn2+‐enhanced 1H2O MRI in hypoxic,perfused rat myocardium

Paramagnetic Mn²⁺ has emerged in the search for non‐invasive magnetic resonance imaging (MRI) techniques to monitor Ca²⁺ in diagnostic and prognostic cardiovascular disease tests because it both alters MRI contrast and behaves as a Ca²⁺ ‘surrogate’ in vivo. However, the reliance on macroscopically averaged measurements to infer microscopic processes constitutes a major limitation of MRI. This investigation circumvents this limitation and contributes an MRI‐based myocardial Ca²⁺‐transporter assay, which probes the Na⁺/Ca²⁺‐exchanger involvement in Mn²⁺ (and presumably Ca²⁺) transport by virtue of its response to pharmacological inhibition. In the model employed herein, ex vivo arrested rat hearts underwent normoxia and then hypoxia while a constant (hyperkalemic) perfusion minimized flow (and uncontrolled Ca²⁺‐channel) contributions to Mn²⁺‐enhanced MRI measurements. The results (i) demonstrate that Mn²⁺ (and presumably Ca²⁺) accumulates via Na⁺/Ca²⁺‐exchanger‐mediated transport during hyperkalemic hypoxia and further, (ii) implicate hypo‐perfusion (rather than the diminished participation of an isolated sarcolemmal Ca²⁺‐transporter) as the mechanism that underlies the reported reductions of Mn²⁺ accumulation (relative to healthy myocardium) subsequent to myocardial insults in MRI studies. Although myriad studies have employed Mn²⁺‐enhanced MRI in myocardial investigations, this appears to be the first attempt to assay the Na⁺/Ca²⁺‐exchanger with MRI under highly circumscribed conditions. MRI‐based Ca²⁺‐transporter assays, such as the Na⁺/Ca²⁺‐exchanger assay utilized here, will inevitably impact disciplines in the medical sciences and beyond. Copyright © 2007 John Wiley & Sons, Ltd.     

具核梭杆菌黏附和侵入上皮细胞的初步研究

目的:本研究以P.gingivalisATCC33277为阳性对照,用KB细胞体外模拟牙龈上皮细胞,初步研究F.nucleatum对上皮细胞的黏附和侵入能力。方法:将实验菌株P.gingivalisATCC33277、F.nucleatumATCC10953以及F.nucleatumWCD05-1分别配制成2×107CFU/mL的菌悬液,加入培养有KB细胞的24孔细胞培养板中。在37℃,50 mL二氧化碳的细胞培养箱中孵育2 h,以P.gingivalisATCC33277为阳性对照,观察F.nucleatum对KB细胞的黏附和侵入。结果:两种F.nucleatum均能黏附和侵入KB细胞。与P.gingivalisATCC33277相比较,F.nucleatumATCC10953的黏附和侵入能力稍弱,而F.nucleatumWCD05-1的黏附和侵入能力更强。结论:F.nucleatum能黏附和侵入上皮细胞,至少在短时间内能保持一定的黏附和侵入量,在细胞内保持一定的活力。F.nucleatum的不同菌株之间黏附和侵入能力存在差异,临床株的毒力明显强于标准株。     

核因子-κB活性在创伤性炎症大鼠肝脏损伤中的变化及其意义

目的探讨核因子-kB（NF-kB）活性在创伤性炎症大鼠肝脏损伤中的变化及其意义。方法Wistar大鼠60只，随机分成对照组和创伤性是症组。运用匀浆法提取肝细胞的核蛋白，运用凝胶阻滞实验检测创伤性炎症术后肝脏组织NF-kB的活性，检测血浆转氨酶的水平，在光镜下观察肝细胞损伤程度，电镜下观察肝脏超微结构改变，以线拉体的肿胀程度作为肝细胞损伤的评价指标。结果大鼠创伤性炎症术后第3小时，肝脏NF—kB的活性开始升高，第12小时达高峰，第72小时后基本降至正常。血浆ALT含量在伤后明显上升。于第24小时达高峰，同时肝细胞出现明显的水肿、变性和坏死，肝小叶结构破坏明显。结论大鼠创伤性炎症肝脏损伤后，NF—kB活性明显升高。与肝脏结构和功能改变基本一致，NF—kB在创伤性炎症肝脏损伤中具有重要意义。     

LY294002逆转KB/VCR细胞多药耐药的作用及机制

目的 探讨蛋白激酶抑制剂LY294002对多药耐药细胞KB/VCR的耐药逆转作用及逆转机制.方法 采用MTT法检测LY294002对VCR和ADR的耐药逆转作用,流式细胞仪检测Rh123在KB和KB/VCR细胞内的蓄积,Western blot法检测LY294002对P-gp蛋白表达的影响,DAPI染色检测细胞凋亡.结果 LY294002对化疗药物具有协同增效作用,可以显著逆转KB/VCR的耐药性,能明显减少Rh123的外排,同时降低P-gp的表达.结论 LY294002能够逆转KB/VCR细胞的多药耐药性,不仅能够抑制P-gp功能,而且能够降低P-gp蛋白表达,使肿瘤细胞内化疗药物的浓度增加,提高化疗药物的杀伤作用.     

肾茶联合泼尼松对多柔比星肾病大鼠核因子-KB、白介素-8水平的干预研究

目的：通过现察多柔比星肾病大鼠核因子-KB、白介素-8水平变化,探讨肾茶联合泼尼松对肾病综合征的保护机制.方法：50只雄性Wistar大鼠随机分为正常组,模型组,肾荼组及肾荼与泼尼松联合治疗组.除正常组大鼠外单次尾静脉注射多柔比星5mg/kg来制备肾病模型,用酶联免疫吸附法检测核因子-KB、白介素-8.结果：各组大鼠尿蛋白、核因子-KB及白介素-8均明显高于正常组（P＜0.01）;肾荼组和联合治疗组的尿蛋白、核因子-KB及白介素-8均低于肾病组（P＜0.01）,但联合治疗组降低更明显,与肾茶组比较差异有显著性（P＜0.01）.结论：肾荼与泼尼松联合治疗组可有效降低核因子-KB和白介素-8水平,其机制可能通过下调核因子-KB和白介素-8表达,从而对多柔比星肾病大鼠起保护作用.     

核因子NF—kB对帕金森病MPTP模型小鼠黑质区iNOS表达的影响

①目的观察核因子NF—KB（nuclearfactorkappaB）对1-甲基-4-苯基-1,2,3,6-四氢吡啶（MPrrP）制备的帕金森病（PD）小鼠模型黑质区诱导型一氧化氮舍酶（induciblenitricoxide,iNOS）表达的影响,以及给予人参皂甙Rgl（GinsenosideRgl,Rgl）后表达的变化,探讨在PD发病过程中NF—KB对iNOS的表达调控作用以及人参皂甙Rgl对PD可能的防治作用。②方法采用MPl．P制备PD小鼠模型,观察小鼠行为学变化;采用免疫组织化学和免疫蛋白印迹法观察小鼠黑质区酪氨酸羟化酶（tyrosinehydroxylase,TH）、NF—KB和iNOS的表达变化;并观察给予人参皂甙Rgl后对上述变化的影响。③结果与对照组相比,模型组小鼠出现典型PD症状,黑质区TH阳性神经元明显丢失、蛋白水平下降,NF—KB和iNOS表达也明显增加,二者表达呈正相关关系;经人参皂甙Rgl处理后,上述变化均明显减轻。④结论在MPllP所致PD模型小鼠中,核因子NF—KB对黑质区iNOS表达可能起重调控作用,人参皂甙Rsl可能通过影响NF—KB表达从而发挥对多巴胺能神经元的保护作用。     

人表皮癌细胞在裸鼠体内的移植

将人表皮癌细胞ＫＢ－３－１及其阿霉素抗性细胞ＫＢ－Ａ－１接种于裸小鼠ＢＡＬＢ／ｃ－ｎｕ前肢左腋下,经８～９ｄ的潜伏期,在小鼠左前肢长出肿瘤,建立了裸小鼠人表皮癌模型。     

具核梭杆菌调控牙龈卟啉单胞菌感染对口腔鳞状细胞癌KB细胞周期和细胞因子分泌的研究

目的: 通过研究牙龈卟啉单胞菌(Porphyromonasgingivalis, P. gingivalis)和具核梭杆菌(Fusobacteriumnucleatum, F. nucleatum)感染对KB细胞的细胞周期和炎症因子分泌的调控,初步探讨牙周细菌感染对口腔鳞状细胞癌进展和炎症反应的影响。方法: 建立P. gingivalis和F. nucleatum单独或联合感染KB细胞模型,透射电镜观察细菌感染细胞情况,流式细胞术检测细胞周期变化,酶联免疫法检测IL-6和IL-8蛋白分泌水平。结果: P. gingivalis联合F. nucleatum感染KB细胞8 h抑制细胞周期进程,感染24 h后加速细胞周期进程;P. gingivalis联合F. nucleatum感染促进KB细胞分泌IL-6和IL-8,并且有时间和F. nucleatum浓度依赖性。结论: 牙周致病菌之间的联合作用更能促进口腔鳞状细胞癌的发展及免疫炎症反应。     

拓扑特肯诱导人口腔上皮癌细胞凋亡的机制

目的 :研究拓扑特肯 (Topotecan ,TPT)诱导体外培养的人口腔上皮癌细胞 (KB)凋亡的作用及其可能机制 .方法 :体外培养KB细胞 ,加 30mg/L的TPT孵育 1 2 ,2 4和4 8h ,用MTT法检测TPT对KB细胞增殖的作用 ;DNA凝胶电泳和流式细胞仪技术检测TPT诱导KB细胞凋亡 ,West ern blot检测 p p38MAPK的表达 .结果 :TPT处理细胞 1 2 ,2 4和 4 8h后 ,KB细胞的抑制率分别为 (2 4± 9) % ,(34±7) %和 (4 5± 1 0 ) % ,各组间有显著性差异 (P <0 .0 5 ) ;流式细胞仪检测其凋亡率 ,1 2h时 (1 1 .5± 2 .8) % ,2 4h(31 .2± 4 .1 ) % ,各组间有显著性差异 (P <0 .0 1 ) ;DNA凝胶电泳可见TPT作用 1 2h组DNA碎片化 ,是典型的细胞凋亡生化指标 ;TPT处理细胞 1 2 ,2 4和 4 8h后 ,KB细胞的 p p38MAPK表达逐渐升高 (n =3,P <0 .0 5 ) .结论 :TPT可通过p p38MAPK开放表达信号通路诱导体外培养的TPT处理KB细胞凋亡 .     

Polymorphisms of RPS6KB1 and CD86 associates with susceptibility to multiple sclerosis in Iranian population

Objective: Multiple sclerosis (MS) is the most prevalent disorder of nervous system inflammation which involves demyelination of spinal cord; this process depends on both environmental and genetic susceptibility factors. In the present study, we examined the association between two SNPs in RPS6KB1 (rs180515) and CD86 (rs9282641) with MS in Iranian population. RPS6KB1gene encodes p70S6K1 protein which plays a key role in mTOR signaling pathway, while CD86 gene codes a membrane protein type I which belongs to immunoglobulin super family act on co-stimulation signaling pathway. Methods: In this case-control study 130 patients with MS and 128 matched healthy controls were enrolled, genomic DNA was isolated and genotyping was performed using mismatched PCR-RFLP. The results were finally analyzed using SPSS. Results: Our results showed significant difference in allelic frequency of SNP rs180515 among cases and controls (P = 0.004). For this variation, AA genotype was shown to have protective effect (P = 0.016 and OR = 0.6), while GG genotype was a susceptive genotype to MS (P = 0.04 and OR = 2.2). Allelic frequency of SNP rs9282641 also showed significant difference between cases and controls (P = 0.006). For this SNP, AG genotype had predisposing effect (P = 0.04, OR = 2.3), and GG genotype showed protective (P = 0.01, OR = 0.411).

Conclusion: We successfully replicated the association of two novel SNPs introduced by a GWAS study, and MS in the Iranian population. This result can open ways for better understanding the mechanisms involved in MS.