DTI at long diffusion time improves fiber tracking

While diffusion‐tensor‐imaging tractography provides remarkable in vivo anatomical connectivity of the central nervous system, the majority of DTI studies to date are predominantly limited to tracking large white‐matter fibers. This study investigated DTI tractography using long diffusion time (t_diff) to improve tracking of thinner fibers in fixed rhesus monkey brains. Stimulated Echo Acquisition Mode (STEAM) sequence on a 3T Siemens TRIO was modified to include a diffusion module. DTI was acquired using STEAM with t_diff of 48 and 192 ms with matched signal‐to‐noise ratios (SNR). Comparisons were also made with the conventional double‐spin echo (DSE) at a short t_diff of 45 ms. Not only did the fractional anisotropy increase significantly with the use of long diffusion time, but directional entropy measures indicated that there was an increased coherence amongst neighboring tensors. Further, the magnitude of the major eigenvector was larger at the t_diff = 192 ms as compared to the short t_diff. Probabilistic connectivity maps at long t_diff showed larger areas of connectivity with the use of long diffusion time, which traversed deeper into areas of low anisotropy. With tractography, it was found that the length of the fibers, increased by almost 10% in the callosal fibers that branch into the paracentral gyrus, the precentral gyrus and the post central gyrus. A similar increase of about 20% was observed in the fibers of the internal capsule. These findings offer encouraging data that DTI at long diffusion time could improve tract tracing of small fibers in areas of low fractional anisotropy (FA), such as at the interfaces of white matter and grey matter. Copyright © 2010 John Wiley & Sons, Ltd.     

Supraventricular Tachycardia Control with Tachylog II: Long-Term Follow-Up

SULKE, A.N., ET AL.: Supraventricular Tachycardia Control with Tachylog 11: Long-Term Follow-Up. Ten patients aged 16–63 years (mean 36.3) had the Siemens P56T "Tachylog II" pacemaker implanted for treatment of drug refractory supraventricular tachycardia. The pacemaker incorporates a noninvasive electrophysiological study (EPS) facility and a sophisticated Holter function combined with a unique "learning" self-search antitachycardia algorithm. The Holter reveals that new tachycardias arise that are not previously detected at conventional EPS. The number of stimuli in the initiation sequences during noninvasive EPS proved highly variable, however, termination sequences remained constant in the long term. There was variability of timing of stimuli in the long term that was significantly greater for "new" tachycardias than for "original" arrhythmias. Long-term follow-up [at 1 month, 6 months, and 1 year] have shown that 90% of patients have good tachycardia control without the need for drugs. All patients confirm the acceptability of this pacemaker for control of their arrhythmias in the long term.     

微量胎儿细胞中Y染色体锌指结构基因自动测序及影响因素的探讨

目的：在已建立的较简便、敏感的对性连锁遗传病胎儿进行产前性别鉴定方法的基础上探讨高温循环全自动测序中几个因素对测序鉴定ZFY基因结果的影响。方法：自行设计ZFY引物并建立了富集胎儿细胞结合巢式聚合酶链反应扩增男性特异性ZFY基因并进一步循环测序方法，计算机辅助设计的两对寡核苷酸引物位于Y染色体短臂的Ucdo43保守区内；同时对DNA纯度、浓度和测序过程中水的质量对DNA自动测序结果的影响进行回顾性分析。结果：实验表明利用孕妇外周血中微量胎儿细胞扩增男性特异性ZFY基因并进行高温循环全自动测序方法可行，结果可靠，在DNA纯度、浓度较低以及配制测序胶时所用纯水水质较差时，对测序曲线造成不同程度的影响，从而影响测序结果。结论：提示该方法检测胎儿DNA是可行的，同时在DNA自动测序鉴定产物特异性时需使用高纯度高浓度的DNA和高质量的纯水，要想获得较长的测序片段，所用模板浓度不能太低。     

肿瘤组织中人乳头瘤病毒HPV基因组相关序列的检测

本文报道应用核酸分子杂交方法,以[α-(32)P]-dTTP标记的HPV16型基因组为探针,共检测恶性肿瘤53例(标本包括宫颈癌22例,阴茎癌3例、膀胱癌6例、肾癌3例、肺癌7例、胃癌1例、结肠癌11例)、7例良性肿瘤、8例正常上皮组织中HPV基因组相关序列。检测结果表明,在恶性肿瘤中仅于宫颈癌组织检测出HPV16型基因组相关序列59.1％,P<0.01。而良性肿瘤和正常上皮组织中均未检测出HPV16型和其他型别基因组相关序列。此种阴性结果,可能与地理分布、病变组织的病理类型、检测使用的探针和方法、例数少等因素有关。为进一步探讨HPV感染与肿瘤的关系,尚需深入研究。     

献血员中TTV感染的检测及部分基因序列分析

目的　探讨湛江地区献血员中输血传播病毒 (TTV)的感染状况及部分TTV的基因序列。方法　采用SDS和蛋白酶K法提取 4 80份正常献血员、6 0份血清丙氨酸转氨酶 (ALT)异常献血员的血清标本DNA ,应用套式PCR方法检测TTV的感染状况 ,并对部分扩增出的阳性片段进行克隆测序 ,与国内外报道的序列进行同源性比较。结果　在 4 80份正常献血员血清标本中 ,5 2份 (10 83% )TTVDNA阳性 ;在ALT异常的 6 0份献血员血清标本中 ,15份TTVDNA阳性 ,阳性检出率为 2 5 % ,明显高于正常献血员人群 (χ2 =9 84 7,P <0 0 1)。序列分析结果显示 ,从献血员中随机选出的 5例TTVDNA阳性片段 ,其序列与日本株 (AB0 0 8394 )和中国株 (TTVCH1)相应位置核苷酸序列的同源性大于97% ,可能属同一基因型。结论　湛江地区献血员中存在TTV感染 ,输血可能成为TTV感染的传播途径之一。     

牙龈卟啉菌蛋白酶的结构和作用

牙龈蛋白酶是牙龈卟啉菌的主要致病因子，因其对宿主蛋白的广泛活性受到了普遍关注本文就牙龈蛋白酶的生化特征、基因结构、蛋白分子结构与作用的研究现状作一综述。     

Relationship among serotype G3P5A rotavirus strains isolated from different host species

The relationship among G3P5A rotavirus strains was analysed by restriction endonuclease assay of the VP4, VP6 and VP7 encoding genes, neutralization assay and phylogenetic analysis. The restriction patterns of the capsid encoding genes were species specific allowing the differentiation among the strains of different origin. The VP7 profiles differentiated human from animal strains more efficiently. The phylogenetic analysis of the VP4 gene demonstrated that HCR3A and K9 are closer related to each other than to other P5A strains. The same occurs to strains Ro1845 and Cat 97. The CU-1 virus appears to be an ancestor of the P5A strains by neutralization and phylogenetic analysis. The results placed the RRV strain definitely in a separate VP4 serotype and genotype from that of P5A strains. Restriction endonuclease assay of the capsid encoding genes seems to be a useful tool to identify the host species of rotavirus strains belonging to the same serotype and/or genotype.     

血小板膜糖蛋白受体I b α Kozak序列基因多态性与缺血性脑血管病相关性的研究

目的研究GP I bαKozak序列基因多态性与缺血性脑血管病的相关性。方法本研究采用聚合链式反应对正常对照组228例和缺血性脑血管病组232例进行研究,对所得结果进行统计学处理,得出GP I bαKozak序列基因多态性与缺血性脑血管病的相关性。结果缺血性脑血管病组Kozak序列C等位基因(TC 33．4％, CC 4．3％)的比例达到37．7％。对照组C等位基因(TC 21．2％,CC 21．8％)的比例为23%,经卡方检验,两组比较, X2=17．378,df=1,P=0．03,具有显著性差异。Kozak序列C等位基因脑栓塞组21．6％;腔梗组28．1％;大面积梗塞组36．3％;对照组与脑栓塞组比较,X2=3．086,df=1,P=0．079,没有显著性差异。与腔梗组比较X2=1．854,df =1,P=0．173,没有显著性差异。与大面积梗塞组比较X2=4．293,df=1,P=0．038,有显著性差异。结论血小板膜糖蛋白受体I bαKozak序列基因多态性与缺血性脑血管病明显相关。     

THE USE OF A SHUTTLE PLASMID TO STUDY NONTARGETED MUTAGENESIS AND ITS SEQUENCE SPECIFICITY

ＴＨＥＵＳＥＯＦＡＳＨＵＴＴＬＥＰＬＡＳＭＩＤＴＯＳＴＵＤＹＮＯＮＴＡＲＧＥＴＥＤＭＵＴＡＧＥＮＥＳＩＳＡＮＤＩＴＳＳＥＱＵＥＮＣＥＳＰＥＣＩＦＩＣＩＴＹＺｈａｎｇＸｉａｏｓｈａｎ（张小山）；ＹｕＹｉｎｇｎｉａｎ（余应年）ａｎｄＣｈｅｎＸｉｎｇｒｕｏ...