Astrocytes and intracerebral immune responses

The astrocyte is the most abundant cell within the central nervous system (CNS). This cell subserves a multiplicity of important functions that contribute to the process of neural development as well as to the integrity of normal brain function. Adding to the already exhaustive list of capabilities, the astrocyte has now been demonstrated to function as an intracerebral antigen presenting cell. These findings are serving to revise our view of the brain as an immunoprivileged site and perhaps will shed some light on the pathogenetic mechanisms involved in a number of CNS disorders of immune dysregulation. In this review we provide some perspective on the regulatory mechanisms that influence astrocyte immune functions. Specifically, we address the role played by the major histocompatibility complex (MHC) antigens as well as adhesion molecules in the initiation of brain immune responses.     

HLA antigens in affective disorders and schizophrenia

The distribution of HLA antigen frequencies has been studied in patients with affective disorders. There were no significant differences between bipolar patients, unipolar patients, or controls. Preliminary data on HLA antigen distribution in schizophrenic patients are reported. Our negative results in affective disorders are discussed in relation to HLA studies reported from other laboratories, with special reference to some potential methodological problems.     

Effect of postactivation potentiation on dynamic knee extension performance

Six men and four women performed, in separate trials, maximal dynamic knee extensions with loads of 15%, 30%, 45% and 60% of maximal isometric knee extension peak torque (MVC). The dynamic extensions were done after postactivation potentiation (PAP) had been induced with a 10-s MVC, and in a control trial without PAP. PAP, measured as the increase in evoked twitch torque, was 53 (4)% (SE) and 43 (3)% at the time of the first and second extensions with each load. PAP failed to increase the attained peak velocity with any load; on the contrary, there was a trend for peak velocity to decrease in the first extension, which occurred ≅15 s after the 10-s MVC. The results suggest that fatigue produced by the 10-s MVC suppressed any benefit that could be derived from the induced PAP. A surface electromyogram (EMG) recorded from one muscle of quadriceps femoris gave no indication of activation failure in the first knee extension; however, activation impairment specific to the rate of force development cannot be ruled out. It is concluded that the strategy employed, namely of having knee extensions performed soon after the 10-s MVC to maximize PAP at the time of performance, was unsuccessful because there had been insufficient time for recovery from fatigue. It is possible that a longer recovery time, even at the cost of a diminished PAP, may have proved beneficial. Accepted: 27 July 2000     

Changes in the P100 latency of the visual evoked potential and the saccadic reaction time during isometric contraction of the shoulder girdle elevators

We investigated changes in the P100 latency of the visual evoked potential (VEP) and the saccadic reaction time (SRT) in relation to the degree of activity of the shoulder girdle elevators. Muscle force was set in 10% increments from 0% to 50% of the maximal voluntary contraction (MVC). The VEP was derived from a midline occipital electrode with reference electrodes on the ears when the right retina was stimulated through the eyelid by light emitting diodes while the eyes were closed. The P100 latency of the VEP was defined as the time from the stimulus onset to the main positive peak. The SRT was defined as the latency until the beginning of eye movement toward the lateral target, which was moved at random time-intervals. P100 latency was shortened until 30% of the MVC, and which it lengthened. The SRT changed in a pattern similar to that observed for the P100 latency. The ratio of the shortening in P100 latency relative to that of the SRT was approximately 20%. All data is presented as the mean value, plus the standard deviation. We believe that the information processing time in the neural pathway from the retina to the visual cortex was shortened up to a certain muscle force of the shoulder girdle elevators, and then this processing time lengthened. These findings indicate that shortening of information processing time in the neural pathway beyond the visual cortex is included in the shortening of the SRT.     

Cornelia de Lange syndrome in a mother and daughter

The Cornelia de Lange syndrome was first described in 1933. Since then, more than 250 cases have been described in the medical literature. It has generally been considered to be sporadic, but several authors have raised the possibility of genetic factors. We present a mother and child affected with Cornelia de Lange syndrome and raise the possibility of autosomal dominant inheritance.     

Linking DJ-1 to neurodegeneration offers novel insights for understanding the pathogenesis of Parkinson’s disease

Rare monogenic forms of Parkinson's disease (PD) are promoting our understanding of the molecular pathways involved in the common, non-Mendelian forms of the disease. Here, we focus on PARK7, an autosomal recessive form of early-onset parkinsonism caused by mutations in the DJ-1 gene. We first review the genetics of this form and the rapidly expanding knowledge about the structure and biochemical properties of the DJ-1 protein. We also discuss how DJ-1 dysfunction might lead to neurodegeneration, and the implications of this novel piece of information for the pathogenesis of the common PD forms. Although much work remains to be done to clarify the biology of DJ-1, its proposed activity as a molecular chaperone and/or as oxidative sensor appear intriguing in the light of the current theories on the pathogenesis of PD.     

Interstitial deletion in the long arm of chromosome no. 5

A case of a male infant with several congenital anomalies combined with an interstitial deletion of the long arm of chromosome no. 5 is presented. The symptoms of the infant were compared to five previous reported cases with similar interstitial deletions in 5q.     

血糖感应型胰岛素给药智能载体的研究进展

胰岛素控制释放高分子载体系统一直是国内外科技工作者的研究热点 ,迄今已经研究报道了多种具有不同工作原理的血糖感应型胰岛素给药智能载体。本文基于国内外大量研究文献 ,综述了血糖感应型胰岛素控制释放智能化高分子载体的研究进展。