Correlation between patterns of horizontal connectivity and the extend of short-term representational plasticity in rat motor cortex

Plasticity of representational maps in adult cerebral cortex has been documented in both sensory and motor cortex, but the anatomical basis for cortical plasticity remains poorly understood. To investigate horizontal connectivity in primary motor cortex (M1) as a putative anatomical substrate for short-term, functional plasticity of adult motor cortical representations, a combination of electrical stimulation and biocytin labeling was used to examine pre-existing patterns of intrinsic connections in adult rat M1 in relationship to the pattern of reorganization of the motor movement may induced by transection of the contralateral facial nerve. Two hours after nerve cut, small, circumscribed regions of the forelimb representation expanded medially into territory previously devoted to the vibrissae representation. Outside of this novel, expanded forelimb region, no forelimb movement could be evoked from the former vibrissae representation at any time over the period of hours tested, thus representing silent cortex. Injections placed into vibrissae cortex representing the newly expanded forelimb representation gave rise to labeled axons and dense terminal fiber labeling which crossed the forelimb/vibrissae border and extended up to 1.2 mm within the low-threshold forelimb representation. In contrast, injections placed into silent vibrissae cortex gave rise to labeled axons and terminal boutons which remained mostly restricted to the original vibrissae representation, with only sparse projections that crossed into the low-threshold forelimb representation. Thus, these results suggest that the extent of short-term, functional reorganization of M1 induced within the first several hours following peripheral nerve cut is mediated, and constrained, by an anatomical framework of pre-existing, horizontal projections which traverse representation borders.      

Transobturator slings for stress incontinence: using urodynamic parameters to predict outcomes

The purpose of this study is to evaluate the ability of preoperative urodynamic urethral function parameters to predict the success rate of transobturator slings (TOS). Seventy women urodynamically diagnosed with stress incontinence with urethral hypermobility underwent a Monarc™ TOS (American Medical Systems, Minnetonka, USA). Postoperative continence status was correlated with preoperative urodynamic urethral function parameters. Mathematical modeling was used to determine whether urodynamic parameters can be used to predict postoperative continence. Average follow-up was 8.1 (6–12) months; 56 (80%) patients were continent based on a standardized stress test and subjective report. The median Valsalva leak point pressure at 150 cc (VLPP₁₅₀) in the failures and successes was not different (p = 0.12). The median VLPP at cystometric capacity (VLPP_cap) in the failures was 32 cmH₂O compared to 71 cmH₂O in the successes (p < 0.001). The maximum urethral closure pressure (MUCP) had a median of 20 cmH₂O in the failures and 45 cmH₂O in the successful patients (p < 0.001). No correlation existed between the degree of urethral hypermobility, as measured by the cotton swab test, and surgical success (p = 0.17). There was no correlation between level of preoperative urethral function and persistent overactive bladder symptoms, post-void residual, voids/day, and nocturia. Using a combined model, the cutoff values of VLPP_cap > 60 cmH₂O and MUCP > 40 cmH₂O were the most predictive of surgical success, revealing a sensitivity of 83% (0.55, 0.95) and specificity of 79% (0.67, 0.88). A combination of urodynamic parameters can be used to predict continence rates after a TOS. A TOS should be used with caution in women with impaired urethral function. G. Willy Davila is a consultant to American Medical Systems.     

Vascular endothelial growth factor in exercising humans under different environmental conditions

It was the aim of this study to investigate the time course of changes in the serum concentrations of vascular endothelial growth factor (VEGF) during a regular survival training programme combined with food and fluid deprivation and during a high altitude marathon run. We studied soldiers of the Austrian Special Forces performing survival training at sea-level and marathon runners of the Posta Atletica who crossed the border between Chile and Argentina at altitudes up to 4722?m. Baseline data collected before the 1-week of survival training showed that the soldiers had normal VEGF [n=8, 246.7?(SD 118.5)?pg?·?ml^?1] serum concentrations which remained unchanged during the course of the study. Before the high altitude marathon the subjects showed normal VEGF serum concentrations [178?(SD 84.5)?pg?·?ml^?1]. After the run VEGF concentrations were found to be significantly decreased [41.0?(SD 41.6)?pg?·?ml^?1, P?相似文献   

荧光原位杂交法快速鉴定血培养阳性葡萄球菌的临床应用

目的快速鉴定血培养中的金黄色葡萄球菌和凝固酶阴性葡萄球菌(CoNS),结合临床快速判定是否为污染菌。方法采用荧光原位杂交法鉴定血培养中的金黄色葡萄球菌和CoNS,杂交结果若为CoNS,根据临床资料进行判断,并与文献推荐的污染判断法进行结果比较。结果探针的特异性经由标准菌株和临床分离菌株证实。金黄色葡萄球菌探针的特异性和敏感性均为100%,GoNS探针的特异性和敏感性分别为100%和95.5%。179株CoNS中117株判断为污染菌,污染率为68%,与文献推荐的污染判断方法一致。结论荧光原位杂交法适用于血培养中的金黄色葡萄球菌和CoNS的快速鉴定,以排除CoNS污染。     

The relative contributions of pre-neural and neural factors to areal summation in the fovea

In order to determine the relative contributions of pre-neural and neural factors to areal summation in the fovea, measurements of Ricco's area were made. These were compared to the results of an ideal-observer analysis which incorporated only pre-neural factors, up to the level of the photoreceptor. The comparison indicated that Ricco's area in the fovea is largely (if not completely) accounted for by pre-neural factors. Thus, our results, in agreement with the recent analysis of contrast sensitivity by Banks, Geisler and Bennett (1987; Vision Research, 27, 1915-1924), are consistent with the hypothesis that a neural pathway exists which consists of units whose center mechanisms sum over only a single cone or a single row of cones. Our results also imply that the quantum efficiency for detection is constant for test areas up to 256 min2, once the effects of the optics and receptor aperture are factored out.     

融合蛋白 NrCAM-Fc的重组体的构建

目的：构建神经原相关的细胞粘附分子（NrCAM）和免疫球蛋白Fc片段融合基因的重组质粒并通过Baculovirus载体转染到昆虫细胞。方法：利用RT－PCR方法从神经母细胞瘤细胞系SK－N－SN获得NrCAM的信号肽区和跨膜区片段并直接克隆到pGEMT载体，经多次酶切、连接、转化、筛选获得NrCAM-Fc的重组副合基因，测序后将此基因通过Baculovirus载体转染至昆虫细胞。结果：多种酶切和测序结果表明NrCAM-Fc的序列与原序列符合率达98％以上，NrCAM与Fc连接处序列保证了Fc的读码框架（ORF）。结论：Baculovirus载体转染效率高，检测方法简便易行。     

MGA5 Health Utilities Index: Further Evidence of Responsiveness

Quality adjusted life years (QALYs) are well recognized as a valid measure for outcomes in cost-effectiveness analyses. However, it is difficult to obtain a summary utility score from health status measure such as the SF-36.
OBJECTIVE: To predict a summary utility score (represented by HUI) from the scores on the SF-36.
METHODS: A structural equation framework was applied to data collected from 1992 to 1995 on the Southern California Kaiser Permanente population (n = 5,794). An instrumental variable (IV) method mitigated the endogeneity in estimating the HUI(MarkII). Socioeconomic and disease variables were used as covariates. A split-sample analysis provided cross-validation.
RESULT: This model predicted 33.68% of the observed variance in HUI index scores with an adjusted R²of 0.3335. Observed HUI index scores were distributed with a mean of 0.7963 and std. deviation of 0.1796. Parameter estimates of most of the SF-36 components (except General Health & Social Functioning) showed statistical significance at α= 0.05 level. People with high chronic disease scores were found to have low SF-36 scores, and parameter estimates of this covariate were also found statistically significant at α= 0.05 level in all structural equations. However, all the socioeconomic variables showed statistical insignificance. Comparison of "Forecasting" and "Estimation" sub-samples showed satisfactory results during cross-validation.
CONCLUSION: Result of this study provides a quantitative link between two important measures of health status. The present model can be used to estimate overall health utility summary scores from previous studies using the SF-36.     

Metastatic germ cell tumor to the heart presenting with syncope.

Malignant nonseminomatous germ cell tumors (NSGCT) rarely metastasize to the heart. The first such case presenting with syncope is described. Eight previously described cases of NSGCT with intracaval metastasis to the heart are reviewed and the literature to date is discussed. Transesophageal echocardiography is the diagnostic study of choice and treatment consists primarily of platinum-based chemotherapy followed by surgical resection of residual deposits.