弥漫性轴索损伤患者胼胝体DTI纵向评估

目的 评价亚急性期弥漫性轴索损伤(DAI)患者胼胝体各亚区域微观结构及其短期变化.方法 连续性纳入亚急性期DAI患者21例,其中12例于1月后(31.5 d±6.2 d,28~43 d)复查,招募12例性别、年龄匹配的健康对照组,所有受试者使用3.0T磁共振仪扫描获取脑部DTI数据.在矢状位各向异性分数(FA)图将胼胝体分为6个亚区域(胼胝体膝部、体嘴部、体前部、体后部、峡部及压部)计算FA值、表观扩散系数(ADC)值,分析亚急性期和随访患者胼胝体DTI参数变化,并将亚急性期患者胼胝体各亚区域DTI参数与入院时格拉斯哥(GCS)评分做相关分析.结果 亚急性期患者整个胼胝体及所有亚区域FA值显著降低,除胼胝体体前部、体后部外其余亚区域ADC值均显著升高(P<0.05),其中胼胝体峡部FA值下降幅度最大(-12.0%).12例随访患者整个胼胝体及各亚区域FA值和ADC值变化均无统计学意义(P>0.05).亚急性期患者整个胼胝体、峡部及压部FA值与入院时GCS评分呈正相关(整个胼胝体:r=0.848,P=0.000;峡部:r=0.447,P=0.048;压部:r=0.591,P=0.006).结论 胼胝体峡部是DAI最易损伤的部位;短期内(1个月)胼胝体亚区域微观结构无显著变化;亚急性期DAI患者整个胼胝体FA值能较好反映DAI患者损伤程度.     

MR T1WI纹状体高信号表现分析

目的探讨纹状体MRT1WI高信号病变的影像表现,并结合文献讨论其发生机制及病理改变。资料与方法回顾性分析32例纹状体MRT1WI高信号病变的影像表现,包括亚临床性肝性脑病,钙化、脑梗死及CO中毒性脑病。结果亚临床性肝性脑病患者表现为多个部位的T1WI高信号,主要累及部位有苍白球,壳核,中脑红核周围,T2WI及CT上未见异常,T2WI梯度回波上呈明显或较低信号;钙化表现为纹状体对称的T1WI高信号,其信号强度不均匀,T2WI上表现为稍低、等或高信号,CT表现为高密度;脑梗死后病变表现为纹状体点片状T1WI高信号,T2WI上可见比,T1WI上范围大的高信号;CO中毒性脑病表现为双侧纹状体对称性T1WI高信号,其信号强度不均匀,主要累及苍白球,T2WI上其周围深部白质可见大片状高信号。结论纹状体T12I高信号主要与金属顺磁性物质（锰、钙、铁等）的沉积有关。结合临床表现及实验室检查可以做出正确地诊断与鉴别诊断。     

Calcified meconium balls in a newborn: an unusual case with imperforate anus,rectourinary fistula,colpocephaly, and agenesis of corpus callosum

Calcified intraluminal meconium is a rare finding in newborn infants. It is often associated with communication between the urinary and gastrointestinal tracts. Intra-abdominal calcifications are unusual radiographic findings in the newborn and can easily be misinterpreted as meconium peritonitis. We report on a newborn infant with anorectal malformation, meconium balls, intraluminal calcifications, colpocephaly, and agenesis of the corpus callosum, a rare association.     

19q13.32 microdeletion syndrome: Three new cases

A previous report described a unique phenotype associated with an apparently de novo 732 kb 19q13.32 microdeletion, consisting of intellectual disability, facial asymmetry, ptosis, oculomotor abnormalities, orofacial clefts, cardiac defects, scoliosis and chronic constipation. We report three unrelated patients with developmental delay and dysmorphic features, who were all found to have interstitial 19q13.32 microdeletions of varying sizes. Both the previously reported patient and our Patient 1 with a larger, 1.3-Mb deletion have distinctive dysmorphic features and medical problems, allowing us to define a recognizable 19q13.32 microdeletion syndrome. Patient 1 was hypotonic and dysmorphic at birth, with aplasia of the posterior corpus callosum, bilateral ptosis, oculomotor paralysis, down-slanting palpebral fissures, facial asymmetry, submucosal cleft palate, micrognathia, wide-spaced nipples, right-sided aortic arch, hypospadias, bilateral inguinal hernias, double toenail of the left second toe, partial 2–3 toe syndactyly, kyphoscoliosis and colonic atony. Therefore, the common features of the 19q13.32 microdeletion syndrome include facial asymmetry, ptosis, oculomotor paralysis, orofacial clefting, micrognathia, kyphoscoliosis, aortic defects and colonic atony. These findings are probably related to a deletion of some combination of the 20–23 genes in common between these two patients, especially NPAS1, NAPA, ARHGAP35, SLC8A2, DHX34, MEIS3, and ZNF541. These candidate genes are expressed in the brain parenchyma, glia, heart, gastrointestinal tract and musculoskeletal system and likely play a fundamental role in the expression of this phenotype. This report delineates the phenotypic spectrum associated with the haploinsufficiency of genes found in 19q13.32.     

Critical role of Nitric Oxide on Nicotine‐Induced Hyperactivation of Dopaminergic Nigrostriatal System: Electrophysiological and Neurochemical evidence in Rats

Nicotine, the main psychoactive ingredient in tobacco, stimulates dopamine (DA) function, increasing DA neuronal activity and DA release. DA is involved in both motor control and in the rewarding and reinforcing effects of nicotine; however, the complete understanding of its molecular mechanisms is yet to be attained. Substantial evidence indicates that the reinforcing properties of drugs of abuse, including nicotine, can be affected by the nitric oxide (NO) system, which may act by modulating central dopaminergic function. In this study, using single cell recordings in vivo coupled with microiontophoresis and microdialysis in freely moving animals, the role of NO signaling on the hyperactivation elicited by nicotine of the nigrostriatal system was investigated in rats. Nicotine induced a dose‐dependent increase of the firing activity of the substantia nigra pars compacta (SNc) DA neurons and DA and 3,4‐dihydroxyphenylacetic acid (DOPAC) release in the striatum. Pharmacological manipulation of the NO system did not produce any change under basal condition in terms of neuronal discharge and DA release. In contrast, pretreatments with two NO synthase (NOS) inhibitors, N‐ω‐nitro‐l ‐arginine methyl ester (l ‐NAME) and 7‐nitroindazole (7‐NI) were both capable of blocking the nicotine‐induced increase of SNc DA neuron activity and DA striatal levels. The effects of nicotine in l ‐NAME and 7‐NI‐pretreated rats were partially restored when rats were pretreated with the NO donor molsidomine. These results further support the evidence of an important role played by NO on modulation of dopaminergic function and drug addiction, thus revealing new pharmacological possibilities in the treatment of nicotine dependence and other DA dysfunctions.     

Alcohol exposure during the first two trimesters-equivalent alters the development of corpus callosum projection neurons in the rat.

Children exposed prenatally to alcohol can display a variety of neural deficits, including an altered development of the corpus callosum (CC), the largest interhemispheric axon pathway in the brain. Furthermore, these children show functional abnormalities that are related to brain regions with significant numbers of CC connections. Little is known about how alcohol imparts influence on CC development, but one possible mechanism is by affecting the corpus callosum projection neurons (CCpn) directly. The purpose of this study was to quantify the effects of prenatal alcohol exposure on the number, size, and distribution of CCpn within the visual cortex. The visual cortex was selected specifically due to the many vision-related deficits noted in fetal alcohol exposed children and because the critical role of the CC in visual cortex development is well documented. Sprague-Dawley rat pups received one of four alcohol dosages during gestational days (G) 1-20, or reared as nutritional or untreated control animals. Each litter was categorized according to the peak blood alcohol concentration experienced. Pups were removed from each litter on days equivalent to G29, G36, G43, and G50, for histology and measurement. Callosal axons were labeled retrogradely to their CCpn using 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) and the CCpn were then examined using confocal laser scanning microscopy. Differences between alcohol-exposed and control animals were observed in CCpn cell body size, number, and location with the cortex. This was particularly true of animals exposed to high doses of alcohol. In addition, some trends of CCpn development were found to be unchanged as a result of prenatal alcohol exposure. The results demonstrate clear differences in the development of CCpn in the visual cortex between alcohol-exposed and control animals and suggest that this development is particularly affected in those animals exposed to high doses of alcohol.     

LRH-A对人胎盘和妊娠大鼠脑垂体-卵巢-子宫及胎盘作用的研究

本文研究大剂量LRH-A对人早孕胎盘绒毛、大鼠的脑垂体、卵巢、子宫和胎盘的作用。实验结果表明,大剂量LRH-A可使妊娠大鼠子宫内膜、胎盘淤血坏死,胚胎发育停滞,黄体退变及局灶性坏死,黄体细胞3β-HSD酶活性显著减弱,但大鼠垂体促性腺激素细胞超微结构没有受到明显影响。LRH-A可促进体外培养人绒毛hCG的分泌,并损害绒毛上皮的组织结构。     

A brief history of brain iron research

We present a patient with transient global amnesia (TGA) whose diffusion-weighted imaging (DWI) study showed a high-intensity signal in the left retrosplenium of the corpus callosum. In previous studies, lesions in the retrosplenium caused permanent but not transient global amnesia, called retrosplenial amnesia, by involving the thalamocortical portion of the Papez' circuit. This is the first report indicating that TGA can be associated with acute infarction only in the left retrosplenium of the corpus callosum.     

Cortical and subcortical contributions to the representation of temporal information

Converging evidence suggests that temporal representations of brief durations are derived subcortically. We tested split-brain patient JW in order to investigate whether these representations project bilaterally or unilaterally to cortex. Using visual stimuli to signal time intervals, JW was asked to compare the duration of a pair of standard stimuli that were presented bilaterally with a comparison stimulus that was presented to either the left or right visual field. Assuming the hand of response is controlled by the contralateral cerebral hemisphere, a hand by visual field interaction was predicted if the representation of stimulus duration was restricted to the cerebral hemisphere receiving the lateralized stimulus. However, we failed to observe this interaction for two different ranges of stimulus durations, both in the hundred (Experiment 2) to hundreds (Experiment 1) of milliseconds range. Instead, there was a consistent right hemisphere advantage in task performance. When the task then required a discrimination based on the physical size of the stimuli rather than their duration, an interaction between response hand and visual field was obtained (Experiment 3). Taken together, these results suggest that (1) even though the comparison stimulus was presented unilaterally, the representation of its duration was available to both cerebral hemispheres, and (2) a right hemisphere advantage in psychophysical tasks requiring the comparison of successive stimuli is observed for temporal and non-temporal judgments.