Regionally selective atrophy of subcortical structures in prodromal HD as revealed by statistical shape analysis

Huntington disease (HD) is a neurodegenerative disorder that involves preferential atrophy in the striatal complex and related subcortical nuclei. In this article, which is based on a dataset extracted from the PREDICT‐HD study, we use statistical shape analysis with deformation markers obtained through “Large Deformation Diffeomorphic Metric Mapping” of cortical surfaces to highlight specific atrophy patterns in the caudate, putamen, and globus pallidus, at different prodromal stages of the disease. On the basis of the relation to cortico‐basal ganglia circuitry, we propose that statistical shape analysis, along with other structural and functional imaging studies, may help expand our understanding of the brain circuitry affected and other aspects of the neurobiology of HD, and also guide the most effective strategies for intervention. Hum Brain Mapp 35:792–809, 2014. © 2012 Wiley Periodicals, Inc.     

Effect of menstrual cycle phase on dopamine D2 receptor availability in female cynomolgus monkeys

Sex differences have been reported in a variety of affective and neurodegenerative disorders that involve dysfunctional dopamine (DA) neurotransmission. In addition, there is evidence for differences in sensitivity to the abuse-related effects of psychostimulants across the menstrual cycle which may result from effects of ovarian hormones on DA function. The goal of the present study was to extend previous work examining menstrual cycle-related changes in DA D2 receptor availability in humans to drug-naive female cynomolgus monkeys (n=7) using the selective D2-like receptor ligand [(18)F]fluoroclebopride (FCP) and a high-resolution microPET P4 scanner. Menstrual cycle phase was characterized by daily vaginal swabs and measurements of serum progesterone levels. PET studies were conducted once during the luteal phase and once during the follicular phase. Regions of interest in the caudate nucleus, putamen, and cerebellum were defined on coregistered MRIs. Distribution volumes were calculated for FCP in each structure and the distribution volume ratio (DVR) for both brain regions relative to the cerebellum was used as a measure of D2 receptor availability. FCP DVRs were significantly higher in the luteal phase compared to the follicular phase in both the caudate nucleus (11.7% difference, p=0.02) and putamen (11.6% difference, p=0.03). These findings extend earlier work in humans and suggest that changes in DA receptor availability may be involved in the variation in symptoms of various neuropsychiatric disorders across the menstrual cycle, including differences in sensitivity to the abuse-related effects of stimulants.     

Pathophysiological mechanisms of dominant and recessive KVLQT1 K+ channel mutations found in inherited cardiac arrhythmias

The inherited long QT syndrome (LQTS), characterized by a prolonged QT interval in the electrocardiogram and cardiac arrhythmia, is caused by mutations in at least four different genes, three of which have been identified and encode cardiac ion channels. The most common form of LQTS is due to mutations in the potassium channel gene KVLQT1, but their effects on associated currents are still unknown. Different mutations in KVLQT1 cause the dominant Romano-Ward (RW) syndrome and the recessive Jervell and Lange-Nielsen (JLN) syndrome, which, in addition to cardiac abnormalities, includes congenital deafness. Co- expression of KvLQT1 with the IsK protein elicits slowly activating potassium currents resembling the cardiac Iks current. We now show that IsK not only changes the kinetics of KvLQT1 currents, but also its ion selectivity. Several mutations found in RW, including a novel mutation (D222N) in the putative channel pore, abolish channel activity and reduce the activity of wild-type KvLQT1 by a dominant-negative mechanism. By contrast, a JLN mutation truncating the carboxyterminus of the KvLQT1 channel protein abolishes channel function without having a dominant-negative effect. This fully explains the different patterns of inheritance. Further, we identified a novel splice variant of the KVLQT1 gene, but could not achieve functional expression of this nor of a previously described heart-specific isoform.      

Prevention of transfusion-associated graft-versus-host disease: selection of an adequate dose of gamma radiation

To determine the optimal dose of gamma radiation necessary to inhibit T- lymphocyte function and prevent transfusion-acquired graft-versus-host disease (TA-GVHD), a donor plateletpheresis component was initially divided into ten 20-mL samples. One sample was not irradiated, while the other nine samples were treated with gamma radiation at doses ranging from 500 to 4500 cGy. T-lymphocyte function was subsequently measured by mixed lymphocyte cultures and mitogen stimulation assays. The results were assessed in each test by calculating the percentage of inhibition of each irradiated sample as compared to that of the unirradiated sample. The accuracy of the delivered dose of gamma radiation was measured with thermoluminescent dosimeters. It was concluded that a nominal dose of 3000 cGy (actual dose delivered, 2898 cGy) is the appropriate amount of gamma radiation needed to eliminate T- lymphocyte-mediated graft-versus-host disease.     

三种移植物关节镜下重建膝关节前交叉韧带效果比较：2年随访

目的:采用自体骨-髌韧带、自体双股半腱肌腱半膜肌及同种异体跟腱移植重建膝关节前交叉韧带,比较不同移植物的临床疗效。方法:选择1998-06/2003-02中山大学附属第三医院骨科单纯前交叉韧带损伤后行关节镜下重建手术病例96例,患者均签署知情同意书。根据不同移植物分为3组:①自体骨-髌韧带组38例,应用自体中1/3骨-髌韧带-骨移植物。②自体双股半腱肌腱股薄肌腱组22例,应用自体双股半腱肌腱股薄肌腱。③同种异体跟腱组36例,应用同种异体跟腱。术后定期随访,对膝关节活动度、肌力恢复程度、Werner髌股痛评分(最差为0分,最高为55分)、Lysholm评分(0～100分,分数越高膝关节功能恢复越好)、国际膝关节文献委员会评分(按病情严重程度分类分为正常、接近正常、异常、严重异常4个等级)等进行对比观察。结果:①96例患者随访2年,无脱落。②全部患者无感染,未发生髌骨骨折。也未发现关节内粘连、下肢深静脉血栓形成和血管神经损伤等并发症。③膝关节活动度、肌力恢复情况、髌股痛评分:随访结束时3组差异均无显著性意义(P>0.05)。④Lysholm膝关节评分:随访结束时自体骨-髌韧带组由术前(68.2±6.3)分提高至(88.6±6.8)分,自体双股半腱肌腱股薄肌腱组由术前(66.5±6.5)分提高至(86.4±6.6)分,同种异体跟腱组由术前(68.2±6.3)分提高至(86.3±6.2)分,随访结束时各组评分均显著高于术前(P<0.05),3组比较差异无显著性意义(P>0.05)。⑤国际膝关节文献委员会评分(术后活动水平正常或接近正常):随访结束时自体骨-髌韧带组为87%,自体双股半腱肌腱股薄肌腱组为86%,同种异体跟腱组为89%,各组移植术后膝关节功能均有所改善,3组间差异无显著性意义(P>0.05)。结论:关节镜下采用自体骨-髌韧带、自体双股半腱肌腱股薄肌腱和同种异体跟腱移植重建前交叉韧带,均能明显改善膝关节运动功能,3种移植方法的临床疗效无明显差异,提示重建前交叉韧带的术后疗效与移植物种类的相关性不明显。     

构建Loa22基因去信号肽片段原核重组表达载体

目的：构建赖型钩端螺旋体OmpA膜蛋白Loa22基因去信号肽片段的原核表达载体，并对其进行克隆表达。方法：实验于2004—12／2005—12在四川大学华西医学中心感染免疫研究室完成。以赖型钩端螺旋体017株基因组DNA为模板，PCR扩增Loa22基因去信号肽片段，亚克隆至原核表达载体pGEX-4T-1，经双酶切、PCR鉴定，筛选出阳性重组质粒克隆。经DNA测序正确后，转化大肠杆菌，利用IPTG进行诱导表达，通过SDS—PAGE鉴定表达产物。结果：PCR获得长516bp的片段。Loa22基因去信号肽片段与pGEX-4T-1的重组质粒构建成功。重组质粒经IPTG诱导后能在大肠杆菌中表达Mr45000的融合蛋白。结论：制备了Loa22基因去信号肽片段原核重组表达载体，为钩体新型疫苗的研究奠定基础。