Characterization of erythromycin-resistant Streptococcus pneumoniae in Korea, and In Vitro activity of telithromycin against erythromycin-resistant Streptococcus pneumoniae

To characterize the phenotypes and genotypes of erythromycin-resistant clinical isolates of Streptococcus pneumoniae in Korea and to evaluate the in vitro activity of telithromycin against these erythromycin-resistant isolates, we tested a total of 676 isolates of S. pneumoniae collected from 1997 to 2002 in a tertiary hospital in Seoul, Republic of Korea. MICs for erythromycin and telithromycin were determined by the agar dilution method. The macrolide resistance phenotypes of erythromycin-resistant isolates were determined by the erythromycin- clindamycin-rokitamycin triple disk (ECRTD) and MIC induction tests, whereas their macrolide resistance genotypes were determined by PCR for the erm(B), erm(A), subclass erm(TR), and mef genes. To discriminate between mef(A) and mef(E), PCR-restriction fragment length polymorphism (RFLP) analyses were performed. Of the 676 S. pneumoniae isolates, 459 (67.9%) were resistant to erythromycin. Of the 459 erythromycin-resistant isolates, 343 (74.7%) were assigned to the cMLS phenotype, 48 (10.4%) to the iMcLS phenotype, 4 (0.9%) to the iMLS phenotype, and 64 (14.0%) to the M phenotype. The erm(B) gene was detected in 251 (54.6%) isolates, the mef gene was detected in 64 (14.0%), and both the erm(B) and mef genes were detected in 144 (31.4%) isolates. All of the mef genes detected were identified as mef(E). Of the 459 erythromycin- resistant isolates, all but one were susceptible to telithromycin. The MIC(50)/MIC(90) to telithromycin of isolates carrying erm(B), mef(E), and both genes was 0.06/0.5 microg/ml, 0.03/0.125 microg/ml, and 0.5/1.0 microg/ml, respectively. Although the MICs of telithromycin for the erythromycin-resistant isolates varied according to genotype, telithromycin was very active against these erythromycin-resistant S. pneumoniae.     

GABA(B) receptor activation modulates GABA(A) receptor-mediated inhibition in chicken nucleus magnocellularis neurons

Neurons of nucleus magnocellularis (NM), a division of avian cochlear nucleus that performs precise temporal encoding, receive glutamatergic excitatory input solely from the eighth nerve and GABAergic inhibitory input primarily from the ipsilateral superior olivary nucleus. GABA activates both ligand-gated Cl^– channels [GABA_A receptors (GABA_ARs)] and G protein-coupled receptors (GABA_B receptors). The net effect of GABA_AR-mediated input to NM is inhibitory, although depolarizing. Several studies have shown that this shunting, inhibitory GABAergic input can evoke action potentials in postsynaptic NM neurons, which could interfere with their temporal encoding. While this GABA-mediated firing is limited by a low-voltage-activated K⁺ conductance, we have found evidence for a second mechanism. We investigated modulation of GABA_AR-mediated responses by GABA_BRs using whole cell recording techniques. Bath-applied baclofen, a GABA_BR agonist, produced dose-dependent suppression of evoked inhibitory postsynaptic currents (eIPSCs). This suppression was blocked by CGP52432 a potent and selective GABA_BR antagonist. Baclofen reduced the frequency but not the amplitude of miniature IPSCs (mIPSCs) and did not affect postsynaptic currents elicited by puff application of a specific GABA_AR agonist muscimol, suggesting a presynaptic mechanism for the GABA_BR-mediated modulation. Firing of NM neurons by synaptic stimulation of GABAergic inputs to NM was eliminated by baclofen. However, endogenous GABA_BR activity in the presynaptic inhibitory terminals was not observed. We propose that presynaptic GABA_BRs function as autoreceptors, regulating synaptic strength of GABA_AR-mediated inhibition, and prevent NM neurons from generating firing during activation of the inhibitory inputs.     

离心作用测定细胞与材料间的粘附力及其初步应用

目的：介绍一种简单易行的检测细胞与材料间黏附力的方法。方法：本方法的建立基于离心力在转速一定时与半径成正比的原理。医用石膏制备培养皿固定装置，于培养皿底制备材料薄膜（包括有PLGA，PLGA COLI，PLGA COL I FN），待大鼠骨骼肌卫星细胞悬液与其作用一定时间后，一定转速开动离心机。测定未脱落细胞斑的半径R,取均值。结果：上述三种材料表面未脱落大鼠骨骼肌卫星细胞圆斑半径（R）分别为7.96、15.11、26.10mm，三组间有显著性差异。结论：（1）R的变化可反映细胞与材料间粘附力的改变。（2）利用离心作用检测细胞与材料间的粘附力是可行的，尤其适用于同一种细胞与不同材料间粘附力的比较。（3）COL I和FN的使用可以增加大鼠骨骼肌卫星细胞与PLGA间的粘附。     

RT-PCR-ELISA方法检测甲肝减毒活疫苗病毒滴度的初步研究

目的 应用核酸扩增产物测定的固相杂交酶联显色法(RT-PCR-ELISA)检测甲肝减毒活疫苗病毒滴度。方法 应用RT-PCR-ELISA。将标记有生物素的寡核苷酸引物所扩增的疫苗病毒基因产物。与微孔反应板上的特异性探针进行快速杂交，通过辣根过氧化物酶标记的链亲和素进行酶联显色。读取吸光度(A值)。判断结果。应用此法检测了11批甲肝活疫苗滴度。并与常规细胞培养法(CCID50)比较。结果 本方法与细胞培养法的敏感性相仿，具有简便、快速、特异的优点。结论 RTPCR-ELISA法有望代替常规细胞培养法应用于甲肝减毒活疫苗病毒滴度的检测。     

骨髓间充质干细胞复合羟基磷灰石/磷酸三钙植骨材料的体外研究

目的研究兔骨髓间充质干细胞(BMSCs)在羟基磷灰石/磷酸三钙(HA/TCP)植骨材料上的黏附增殖情况。方法抽取兔股骨骨髓,进行贴壁培养BMSCs。在成骨诱导液中诱导BMSCs,于7d用钙钴法检测碱性磷酸酶活性,10d进行茜素红矿化结节染色;在成脂诱导液中诱导BMSCs,于21d进行油红O染色。将BMSCs接种到HA/TCP植骨材料上,加入成骨诱导液,采用倒置显微镜、荧光显微镜及扫描电镜检测,并采用四氮唑蓝(MTT)比色法测定HA/TCP植骨材料上BMSCs的增殖情况。结果BMSCs在成骨诱导液中7d碱性磷酸酶呈强阳性,10d矿化结节染色呈橘红色;在成脂诱导液中,21d油红O染色呈阳性。BMSCs在HA/TCP植骨材料上孔隙周围及孔隙内生长良好并大量增殖。MTT分析结果显示,HA/TCP对BMSCs的体外增殖无抑制作用。结论BMSCs与HA/TCP植骨材料有良好的生物相容性。     

非言语型学习障碍儿童社会信息加工的特点

目的: 探讨非言语型学习障碍儿童社会信息加工特点.方法: 本研究为病例对照研究.根据确定学习障碍儿童的标准,先确定学习障碍儿童,然后对学习障碍儿童进行韦氏儿童智力测验,根据测验结果把学习障碍儿童进一步分为非言语型学习障碍组(23人)、言语型学习障碍组(28人),然后按1:1比例选取对照组(51人).设置儿童与同伴、成人相互作用的三类情景,每类情景又分为模糊和清晰两种情况,对三组儿童进行结构性访谈.结果: ①清晰权威情景下.非言语型学习障碍儿童的编码数显著低于对照组儿童[(2.35±1.15)vs.(3.25±1.27),P＜0.01];对人物意图的判断,非言语型学习障碍儿童选择"恶意"的比率(65%)高于言语型学习障碍儿童(29%)(P＜0.05);在工具效能感上,非言语型学习障碍儿童选择有效的比率(74%)高于言语型学习障碍儿童(36%)(P＜0.05).②非言语型学习障儿童在每个情景故事下的总反应数都显著低于对照组儿童[模糊同伴加入情景:(1.17±0.49)vs.(1.09±0.86).P＜0.01;清晰同伴加入情景:(1.09±0.28)vs.(1.69±0.96),P＜0.01;模糊同伴激惹情景:(1.09±0.41)V8.(1.49±0.78),P＜0.05;清晰同伴激惹情景:(1.17±0.49)vs.(1.65±0.95),P＜0.05:模糊权威情景:(0.96±0.36)vs.(1.37±0.72),P＜0.01;清晰权威情景:(1.00±0.30)vs.(1.37±0.59),P＜0.01].结论: ①清晰权威情景下,非言语型学习障碍儿童编码精确性不如对照组儿童;对他人意图的判断非言语型学习障碍儿童比言语型学习障碍儿童倾向于敌意归因;非言语型学习障碍儿童比言语型学习障碍儿童工具效能感高.②在每个情景下,非言语型学习障碍儿童比对照组儿童生成策略少,反应不灵活.     

抗核糖体抗体阳性判断标准的探讨

目的 :分析针对分子量为 38kD和 或 15 16 5kD多肽抗原的抗核糖体抗体 (anti ribosomalantibodies)与SLE的关系 ,探讨抗核糖体抗体的阳性判断标准及其在SLE中的检出情况。方法 :收集病人血清 2 6 2例 ,包括SLE115例、RA5 7例、硬皮病 2 0例、MCTD39例及其他免疫性疾病 31例 ,用免疫印迹法 (Western blot)检测其抗ENA抗体谱。结果 :分别以同时出现 38kD和 16 5 15kD蛋白条带以及出现 38kD蛋白条带为判断抗核糖体抗体阳性的标准 ,则该抗体对诊断SLE的敏感性和特异性结果分别为 2 8 7% (33 115 )、96 6 % (14 2 14 7)及 17 4 % (2 0 115 )、97 3% (14 3 14 7) ,两者比较敏感性有显著性差异 (P <0 0 5 ) ,特异性无显著性差异 (P >0 0 5 ) ;仅 38kD分子阳性的 14例样本中 ,SLE占大多数 ,显著多于其它疾病 (71 4 %比 2 8 6 % ,P <0 0 5 ) ;38kD分子阳性同时伴抗Sm抗体阳性者多于抗Sm抗体阴性者 ,但无显著性差异 (6 4 3%比 35 7% ,P >0 0 5 )。结论 :抗核糖体抗体 38kD分子与SLE密切相关 ,而与抗Sm抗体相关性不强。以 38kD为主要抗原多肽判断抗核糖体抗体 ,不仅可以提高该抗体的阳性检出率 ,同时也不会降低其对SLE诊断的特异性 ,该判断方法值得推广应用。     

D-二聚体测定与急性早幼粒细胞白血病

目的探讨D -二聚体含量与急性早幼粒细胞白血病(APL)经全反式维甲酸(ATRA)治疗前后弥漫性血管内凝血(DIC)发生率的关系及意义。方法应用ELISA法检测21例APL患者(包括7例合并DIC患者)发病时及应用ATRA治疗后D -二聚体水平的变化 ,并与正常对照组比较。结果21例APL患者治疗前血浆D -二聚体水平(2.38±0.98)mg/L较正常对照组(0.25±0.09)mg/L明显升高(P<0.01) ,其中7/21例并发DIC者(2.52±0.12)mg/L明显高于14/21例不并发DIC者 ,(2.18±0.96)mg/L。结论APL患者D -二聚体检测值随维甲酸治疗逐渐降低 ,并可预测ATRA治疗过程中DIC变化及预后     

再生障碍性贫血患者淋巴细胞表型变化

目的：研究再生障碍性贫血（AA）患者骨髓（BM）及外周血（PB）淋巴细胞及其活化相关分子的表达及临床意义。方法：采用单色和双色免疫荧光标记法，流式细胞仪分析AA患者的BM和PB中淋巴细胞膜分子的表达。结果：AA患者BM和BP中CD8^ 细胞增加，CD4／CD8比例下降，BM在CD25^ 细胞和HLA－DR^ 细胞增多，急性AA增加尤为显著（P＜0．01），BM中CD16^ 或CD56^ 细胞也明显增多（P＜0．05），双标记分析提示T细胞主要为CD8^ 细胞：急性AA患者CD8^ -CD25^ 细胞显著增多（P＜0．01），AA患者BM中淋巴细胞活化相关分子表达增多，尤其4－1BB^ ,CD95L^ 和CD40L＋细胞显著增多（P＜0．01），结论：AA患者BM中淋巴细胞活化相关膜分子增多，是AA免疫功能异常及最终导致造血功能衰竭的原因之一。