Localized deposition of M-cadherin in the glomeruli of the granular layer during the postnatal development of mouse cerebellum

M-cadherin is a Ca2+-dependent cell adhesion molecule of the cadherin family, initially localized at the areas of contact between myotubes during myogenesis, but also detected in the peripheral nerve and at the adult neuromuscular junction. In this study, searching for the expression of M-cadherin in the adult mouse brain, we observed a restricted expression of M-cadherin in one of the three layers of the cerebellar cortex: the granular layer. M-cadherin was accumulated in structures rich in synapses and other intercellular junctions where mossy fibers connect granule cell dendrites, the glomeruli. This molecule was not expressed in the cerebellum during the first steps of postnatal cerebellar neurogenesis: granule cell proliferation and migration and Purkinje cell alignment. M-cadherin expression was first detected at postnatal day (P) 11, after the establishment of the synaptic connections between mossy fibers and granule cell dendrites. It then accumulated in glomeruli during their phase of maturation which is characterized by the formation of puncta adherentia between granule cell dendrites. M-cadherin was undetectable in the cerebella of the weaver and staggerer mutants, lacking granule cells, and therefore mature glomeruli and puncta adherentia. Furthermore, other components classically associated with intercellular junctions, i.e., alpha-caterin, beta-catenin and actin filaments, closely paralleled M-cadherin appearance and colocalized with M-cadherin in the mature glomeruli. M-cadherin, which appears as a molecular marker of glomerulus maturation, might be implicated in the formation, and be the ligand, of adherens junctions encountered in this structure.     

DNA fragmentation in granular cells of human cerebellum following global ischemia

Vulnerability of human cerebellum in two autopsy cases following global brain ischemia was examined histologically by using a specific in situ nick-end labeling method for DNA breaks. In both cases, DNA fragmentation was observed in approximately one-third of the granular cells in cerebellar cortex, whereas Purkinje cells were still alive and no DNA fragmentation was recognized in the nuclei. The present study suggests that some granular cells of cerebellar cortex are more vulnerable to transient ischemia than Purkinje cells and death of granular cells is induced by an apoptotic DNA fragmentation following global brain ischemia.     

Calbindin immunoreactivity in the auricular lobe and interauricular granular band of the cerebellum in bullfrogs

Thirty codependent cocaine and alcohol users were compared with age-, education-, race-, and sex-matched cocaine abusers (N = 30) and normals (N = 30) using an extended Halstead-Reitan Neuropsychological Test Battery to determine whether cocaine abusers with alcohol dependence were more cognitively impaired than singly addicted cocaine abusers. Tests were grouped and analyzed according to 8 major ability areas. Participants who abused both cocaine and alcohol did not differ from normals on the majority of test measures. An unexpected but consistent finding was the poorer performance of the cocaine sample relative to cocaine and alcohol abusers on measures of complex psychomotor and simple motor functioning (ps < .001). Pure cocaine abusers, but not abusers of both cocaine and alcohol, also performed more poorly than normals on a measure of global neuropsychological functioning (p < .01). These results are consistent with previous reports of generally mild cognitive dysfunction in cocaine abusers. The findings also suggest that cocaine and alcohol abusers of relatively young ages may be less cognitively impaired than demographically comparable cocaine abusers. Evidence from studies of vascular functioning in abusers of cocaine and alcohol alone and in combination is discussed as possible explanation for these findings.     

转鼓中颗粒流动层厚度及其影响因素

研究转鼓中颗粒物质流动层厚度随转速的变化能提供颗粒物性的重要信息.该文作者实验研究了几种不同尺寸和形状的颗粒物质在低速转鼓中的流动层厚度变化情况,从理论上分析了影响流动层厚度的主要因素.结果表明:流动层厚度受转鼓半径与颗粒直径的比值K、转速ω和剪切率(γ)的综合作用影响.在试验条件相同的条件下,钢球、沙粒、雾化铁粉和CuP粉4种颗粒物质的流动层厚度均与K成线性关系;剪切率(γ)越高的颗粒物质,其流动层越薄;随转速ω增加,流动层厚度呈增大趋势.     

Expression of corneodesmosin in the granular layer and stratum corneum of normal and diseased epidermis

The stratum corneum (SC) has long been considered as a sort of inert membrane destined to be shed at the surface of the epidermis. During the last two decades, however, several lines of evidence have been reported, suggesting that active physical and chemical changes take place in the horny layer despite the absence of intracytoplasmic organelles. In particular, processing of filaggrin, replacement of the plasma membrane by a ceramide envelope and constant, progressive modification of extracellular lipid multilayers have been put forward. Recently, attention has focused on the intercellular junctions, which may be involved in the regulation of SC desquamation. Corneodesmosin, a newly discovered protein of s.c. desmosomes (corneodesmosomes), is synthesized at the latest stages of keratinocyte differentiation and persists between the horny cells until desquamation occurs. In the present study, we performed immunohistochemical and immuno-ultrastructural investigations on corneodesmosin expression in various skin lesions characterized by abnormal production and/or retention of the horny layer. Our results suggest that corneodesmosin expression is independent from profilaggrin synthesis. We found corneodesmosin in almost all morphologically recognizable corneodesmosomal structures and specifically those which persisted up to the SC surface. Hyperkeratotic lesions which are characterized by an increased number of junctions showed intense immunoreactivity with anticorneodesmosin antibody. A complete absence of corneodesmosin was not observed in any disease. This finding, together with our previous biochemical studies, suggests that corneodesmosin may exert a protective function against proteolytic degradation of corneodesmosomes both in normal skin and in the pathological horny layer.     

Glial fibrillary acidic protein expression but no glial demarcation follows the lesion in the molecular layer of cerebellum

The present study investigates the reactive gliosis following a simple stab wound lesion to a brain area in which a characteristic astroglial architecture exists, i.e., the Bergmann-glia in the molecular layer of cerebellum. While in mammalian brain the Bergmann-glia contains glial fibrillary acidic protein (GFAP), in the avian Bergmann-glia, the cytoskeletal protein is vimentin, which is characteristic for immature astroglia in mammals. The operations were performed on chickens and rats under deep anaesthesia, using a sterile disposable needle. After a 1-week survival period, the animals were overdosed with ether and perfused transcardially with 4% buffered paraformaldehyde. Free-floating sections cut with a vibration microtome were processed for immunohistochemistry against GFAP and vimentin. GFAP immunopositivity of Bergmann-glia appeared in chicken and increased in rat in the lesioned area but the lesion was not surrounded by typical astrocytes and no demarcation was formed in the molecular layer, in contrast to the usual appearance of reactive gliosis, which was observed in the granular layer and in the white matter in both species. Vimentin immunopositivity of the Bergmann-glia also increased around the lesion in both species. The results suggest that a highly developed glial architecture fails to re-arrange into a demarcating scar, which offers an interesting model system to study the importance of glial demarcation. The observations also support that the resident glia is the main component of the glial reaction, and prove the capability of avian Bergmann-glia to express GFAP.     

Actinomycosis infection of the cerebellum

The case is presented of a 37-year-old male with a cerebellar abscess due to Actinomyces israelii. The patient was admitted after dental surgery because of fever and symptoms indicative of raised, intracranial pressure. No abnormalities were detected in peripheral blood and cerebrospinal fluid. CT scan revealed a space-occupying lesion in the left cerebellar hemisphere with perifocal oedema and occlusive hydrocephalus. After emergency external ventriculostomy complete removal of the mass was achieved in a two-stage surgical procedure. Culture of the pus under anaerobic conditions resulted in a growth of Actinomyces israelii, Peptostreptococcus anaerobius and Bifidobacterium adolescentis. A 20-day regimen of antibiotics including penicillin G 10 million U x 3/d and clindamycin 900 mg x 3/d was administered. The patient made a full recovery. Pathogenesis and therapeutic principles of CNS infections due to Actinomyces israellii are discussed.     

Blebs in the mouse cerebellar granular layer as a sign of structural inhomogeneity. 1. Anterior lobe vermis

Blood previously acidified with aqueous saturated ammonium chloride solution was extracted with ethyl acetate. The dried extract was subjected to acetonitrile-hexane partition. The acetonitrile portion was analysed for the presence of acidic and neutral drugs by HPLC-DAD (200 mm x 2.1 mm I.D. microbore ODS-Hypersil column) and GC-FID (25 m narrow-bore x 0.25 mm I.D. HP-5 column with 0.33 micron film thickness). The protocol was found to be suitable for both clinical toxicology (including emergency toxicology) and postmortem toxicology. At least 66 drugs of interest were unequivocally identified by RRTs (HPLC) and UV spectra (DAD) match while another 12 were unequivocally identified by double RRTs match (HPLC and GC). Quantitation was facilitated by incorporating calibration blood standards in each assay batch. The five drugs most commonly encountered in clinical blood specimens (1150 cases) were: paracetamol (47.4% of the cases); chlormezanone (6.6%), theophylline (1.74%), naproxen (1.65%) and mefenamic acid (1.56%). The following drugs were detected in toxicologically significant quantities in postmortem blood specimens (245 cases): phenobarbitone (1.22% of the cases), naproxen (0.82%), chlormezanone (0.82%), theophylline (0.82%), carbamazepine (0.41%) and paracetamol (0.41%).     

Effect of La2O3 on granular bainite microstructure and wear resistance of hardfacing layer metal

The purpose of this work was to investigate the effect of La2 O3 on the granular bainite microstructure and wear resistance of hardfacing layer metal. The hardfacing layer metals with different contents of La2 O3 were prepared. The microstructures of the hardfacing layer metals were observed by field emission scanning electron microscopy(FESEM) and transmission electron microscopy(TEM). The hardness and wear resistance of the hardfacing layer metals were measured respectively. The results indicated that with the increasing content of La2 O3, the amount of granular bainite increased, while that of martensite decreased and that of retained austenite did not change obviously. When the content of La2 O3 was 2.55 wt.%, the volume fraction of the granular bainite in the hardfacing layer metal was 73.2%. Meanwhile, the wear resistance of the hardfacing layer metal was the largest, which was 12100 min/g. The mismatch between the face(100) of LaAlO3 and the face(100) of δ-Fe was 7.1%. Therefore, LaAlO3 could act as moderate effective heterogeneous nuclei of δ-Fe and the granular bainite could be refined.     

Compartmentation and control of arginine metabolism in Neurospora

The fate of [14-C]arginine derived from the medium or from biosynthesis has been examined in Neurospora growing in arginine-supplemented medium. In both cases the label enters the cytosol, where it is used efficiently for both protein synthesis and catabolism before mixing with the majority of the endogenous [12C]arginine pool. Both metabolic processes appear to use the same cytosolic arginine pool. It is calculated that the nonorganellar cytoplasm contains approximately 20% of the intracellular arginine pool when the cells are growing in arginine-supplemented medium. The results suggest that compartmentation of arginine is a significant factor in controlling arginine metabolism in Neurospora. The significance of these results for studies of amino acid metabolism in other eukaryotic systems is discussed.     

Nonmotor functions of the cerebellum.

Reviews the literature to determine the involvement of the cerebellum in psychological processes. Traditional concepts of cerebellar physiology have emphasized motor control functions. It is suggested that this brain structure may participate in sensory integration activities, motor skills learning, visual and auditory discrimination performance, emotion and motivation control, and reinforcement processes. (6 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unilateral aplasia of the cerebellum in Aicardi's syndrome

A case of unilateral aplasia of the cerebellum in a girl with Aicardi's syndrome is described. Aplasia of an entire hemisphere is one of the least frequent malformations of the cerebellum. Hypoplasia, partial hemispheric defects of the cerebellum and, rarely, complete absence of one hemisphere have been described in Aicardi's syndrome, which is associated with multiple systemic and CNS malformations. In our patient, who presented the characteristic trial of infantile spasms, callosal agenesia and retinal lacuna, we also saw right cerebellar aplasia along with other CNS malformations using magnetic resonance. We discuss the possibility that this aplasia arises as the result of a developmental defect of the posterior arterial system of Willis's polygon.     

Regionalization defects in the weaver mouse cerebellum

The mammalian cerebellum consists of parasagittal bands and transverse zones that are laid down early in development. When the adult cerebellum is immunostained for the Purkinje cell-specific antigen zebrin II (i.e., aldolase C), compartmentation is reflected in alternating zebrin II+ (P+) and zebrin II- bands (P ). The zebrin II phenotype is Purkinje cell autonomous; thus, disruptions in the zebrin pattern may reflect early problems in pattern formation. Zebrin II expression has been examined in the weaver (wv) mouse cerebellum. Both zebrin II- and zebrin II Purkinje cells are present in the homozygous weaver (wv/wv) mouse, but they are not distributed normally. In the posterior vermis, although the zebrin II+ bands are wider and multilaminate, the standard compartmentation is present. However, a large zebrin II+ cell mass is absent from the central vermis, and analysis of the anterior lobe reveals several missing zebrin II- bands. The cytoarchitectonic defects in wv mice are not simply related to the Purkinje cell abnormalities. Instead, serial reconstruction reveals two transverse boundaries-one rostrally in lobule VI and the other caudally in lobule IX-that delineate cytoarchitectonic transverse zones important in cerebellar development. The abnormal zebrin expression pattern in wv/wv mice may be secondary to the deletion of a transverse zone. This is the first demonstration that Purkinje cell compartmentation can be altered by mutation; therefore, the wv mutation should prove valuable in understanding cerebellar regionalization.     

Compartmentation of albumin and ferritin synthesis in rat liver in vivo

Infusion of rats with [U-14C]glycine resulted in labelling of glycine and serine in plasma albumin and liver ferritin. The patterms of labelling in these two proteins were not similar, suggesting that each is synthesized from a different pool of free amino acids.     

Large granular lymphocytosis

The isolation from human liver microsomes and identification by electrospray mass spectrometry and tandem mass spectrometry of a new metabolite of IMM-125 resulting from the biotransformation of the amino acid 1 vinylic methyl group to a carboxylic acid, called the IMM-125-COOH metabolite, is described. It was found that the complex of this new metabolite with cyclophilin A is formed less easily than the corresponding cyclophilin A-IMM-125-CH2OH main metabolite and cyclophilin A-IMM-125 complexes. However, when formed, the IMM-125-COOH metabolite-cyclophilin A complex requires more collision-induced dissociation (CID) to dissociate the complex than the complexes formed with the two other ligands. The nanospray tandem mass spectrum of the IMM-125-COOH metabolite-cyclophilin A complex (m/z 1755) gives rise to cyclophilin A-ligand complexes of m/z 1751 by elimination of CO2 and of m/z 1749 by loss of CO2 and H2O or glycerol. Since immunosuppressive activity is known to be dependent on the formation of a binary complex between cyclophilin A and the drug and since the target for the binary complex was found to be the calcium- and calmodulin-dependent protein phosphatase, calcineurin, it could be interesting to measure for structurally related immunosuppressive drugs the CID energy necessary to dissociate the binary complexes in order to evaluate whether a correlation with the phosphatase activity could be derived.     

颗粒物质的堵塞行为

在无序状态体系中形成了屈服应力或者是当应力的驰豫时间超过实验时间尺度时就会形成堵塞（jamming）。近年来,堵塞行为已成为颗粒物质研究中的一个热点和难点问题。文内概述了颗粒物质堵塞的基本概念和临近堵塞的行为特征（如颗粒间应力的形成和分布特征、颗粒构形和密度）,以及相关实验和数值模拟研究得出的重要结论。有关颗粒物质堵塞行为的研究,对探明颗粒物质的本质特征,非晶相变机制,以及人流、物流、交通流、信息流中的瓶颈效应等重大问题的解决将产生积极的推动作用。     

Compartmentation of the type I regulatory subunit of cAMP-dependent protein kinase in cardiac ventricular muscle

The species-dependent compartmentation of type I cAMP-dependent protein kinase (PKA I) and its dissociated regulatory subunit (RI) was examined in the heart by biochemical and immunohistochemical means. PKA I and RI were resolved from type II cAMP-dependent protein kinase and its regulatory subunit by DEAE-Sephacel chromatography of the supernatant and Triton X-100 soluble particulate fractions of heart homogenates. The relative amounts of holoenzymes and subunits were determined by cAMP-binding, protein kinase, 8-N3-[32P]cAMP photoaffinity labeling, and Western blot assays. Rat, rabbit, and guinea pig hearts all contained PKA I to varying degrees, but only in the supernatant fractions. Significant amounts of dissociated RI were found in the supernatant fractions, and to a lesser extent the particulate fractions, of these species. In contrast, though no PKA I was detected in the supernatant or particulate fractions of pig and beef heart, half of the cAMP-binding activity in the particulate fraction was attributed to RI. The results suggest that RI may associate with membrane fractions when it is not associated with the PKA catalytic subunit. Immunohistochemical studies of tissue sections from pig, beef, and rat cardiac ventricle using antibodies directed against RI also revealed species-dependent localization of RI. Cardiac myocyte intercalated discs were stained in pig and beef sections with additional sarcolemmal staining in beef sections. Rat ventricle, which contained large amounts of supernatant PKA I, showed nuclear staining. The localization of RI to cardiac myocyte intercalated discs and sarcolemma in certain species suggests a role(s) for this subunit in mediating cAMP-regulated events in these regions.