牛磺酸对大鼠心脏模拟缺血再灌注损伤的保护作用

在离体大鼠心脏模拟缺血再灌注(I/R)损伤的模型上观察了牛磺酸的心肌保护作用。实验结果发现预先给大鼠牛磺酸灌胃(300mg/kg)三日或再灌注同时给药(20mmol/L),对心肌均有保护作用,明显减少心肌细胞内的Mb、LDH的漏出,降低心肌MDA的生成,减轻细胞内钙的聚集,促进心肌ATP含量的恢复。在本实验条件下预防应用牛磺酸较再灌注的同时应用更为有效,表现为更大程度地减少LDH漏出,抑制心肌MDA生成和钙聚集。结果证明牛磺酸具有心肌保护作用,对于防治心肌I/R损伤可能具有临床应用价值。     

The inhibitory effect of altered collagen II peptide on HLA-DRB1-restricted T-cell activation

It has been known that rheumatoid arthritis (RA)-associated antigenic peptides CII263-272 are coupled with human leucocyte antigen (HLA)-DRB1 and recognized by T-cell receptor (TCR), which in turn induced T-cell proliferation and pathogenesis of RA. Non-T-cell-stimulating type II collagen (CII) peptides might be generated by removing the amino acids responsible for TCR contact and keeping the HLA-DR-binding residues intact. In this study, a panel of altered CII peptides (APs) with consecutive or single substitutions of the TCR-contacting residues were synthesized. Through peptide binding and T-cell activation assays, we demonstrated that altered CII263-272 peptides with substitution of the TCR-contacting residues did not or barely induced T-cell activation; one of the best non-T-cell-stimulating peptide AP268-270 inhibited the binding of wild-type CII263-272 to HLA-DR1 and T-cell activation triggered by wild-type CII263-272 and HA306-318 in a dose-response manner. These data suggest that removal of the TCR-contacting residues of CII263-272 leads to HLA-DRB1 binding and low T-cell-stimulating peptides, which could potentially inhibit the T-cell response induced by HLA-DRB1-binding antigenic peptides.     

X-ray scatter correction algorithm for cone beam CT imaging

Developing and optimizing an x-ray scatter control and reduction technique is one of the major challenges for cone beam computed tomography (CBCT) because CBCT will be much less immune to scatter than fan-beam CT. X-ray scatter reduces image contrast, increases image noise and introduces reconstruction error into CBCT. To reduce scatter interference, a practical algorithm that is based upon the beam stop array technique and image sequence processing has been developed on a flat panel detector-based CBCT prototype scanner. This paper presents a beam stop array-based scatter correction algorithm and the evaluation results through phantom studies. The results indicate that the beam stop array-based scatter correction algorithm is practical and effective to reduce and correct x-ray scatter for a CBCT imaging task.     

Acupoint-specific fMRI patterns in human brain

Specific central nervous system (CNS) responses to acupuncture have recently attracted attention. It is important to understand the differences in fMRI images of the brain evoked by acupuncture at an acupoint and at a nearby "sham" point. Here, we report analyses of fMRI images of the brains of 37 healthy volunteers in response to acupuncture at Liv3 (Taichong) and LI4 (Hegu) versus their sham points. We found common activation areas in response to Liv3 or LI4 acupuncture in the middle temporal gyrus and cerebellum, along with deactivation areas in the middle frontal gyrus and inferior parietal lobule, compared with the effects of acupuncture at sham points. Acupuncture at Liv3 evoked specific activation at the postcentral gyrus, posterior cingulate, parahippocampal gyrus, BA 7, 19 and 41, but deactivation at the inferior frontal gyrus, anterior cingulate, BA 17 and 18, compared with acupuncture at its sham point. Acupuncture at LI4 evoked specific activation at the temporal pole, but deactivation at the precentral gyrus, superior temporal gyrus, pulvinar and BA 8, 9 and 45, compared with acupuncture at its sham point. These observations reveal that acupuncture at acupoints induces specific patterns of brain activity, and these patterns may relate to the therapeutic effects of acupuncture.     

Monoclonal ribosomal P autoantibody inhibits the expression and release of IL-12, TNF-alpha and iNOS in activated RAW macrophage cell line

Monoclonal ribosomal P protein antibody (anti-P mAb) may bind to the cell surface, penetrate into cells, and induce apoptosis of Jurkat T cells. Recently, modulation of cytokines has been considered to be important in the pathogenesis of systemic lupus erythematous (SLE). In this study, effects of anti-P mAbs (9B6) on gene expression of cytokines, apoptosis, and reactive oxygen species in murine macrophage RAW 264.7 were analyzed by RT-PCR and ELISA and those on IL-12 promoter activity was determined in an IL-12p40 promoter-reporter gene transfected cell line RAW (IL-12p40-SEAP). After treating LPS-activated RAW 264.7 with 9B6 for 6 or 24 h, the levels of mRNA and protein expression of IL-12, TNF-alpha, and iNOS were significantly inhibited by 25%, 16%, and 13%, respectively. The IL-12 promoter activity of RAW (IL-12p40-SEAP) was also inhibited by 13-22%. However, inhibitory effects were not observed in cells pre-treated with IgG1 for 1 h. The productions of IL-10 in LPS-activated RAW 264.7 and human macrophages were potentiated by 9B6 up to 65% and 51%, respectively. Since anti-P Abs inhibit productions of IL-12 and TNF-alpha and enhance IL-10 production in macrophages, these autoantibodies may augment Th2 responses and amplify lupus manifestations by causing immunological polarity and lymphocyte dysfunction.     

人工神经网络预滤波的自适应运动心电信号增强器

运动心电图是一种将人体对象置于非平静状态下检测到的心电信号，其特点是运动导致基线严重漂移，肌电干扰显著增加，信噪比低。介绍了一种用人工神经网络预滤波的自适应运动心电信号增强器。运用人工神经网络的非线性和自适应处理的跟踪特性有机地结合设计而成。能降低噪声，提高信噪比，有效地提取运动心电信号。     

Morphological, physiological and biochemical observations on skate electric organ

Summary The electric organs of two species of skate have been examined morphologically, physiologically and biochemically. They can be easily dissociated into innervated or denervated component electrocytes by a Torpedo Ringer's solution containing 1% collagenase. Collagenase treatment did not, however, separate the Schwann cell cover capping the synaptosomes. Isolated electrocytes generate normal MEPP frequencies and show evoked responses for two days in Torpedo Ringer's. The nerve terminals retain excitability and transmitter release properties up to the time of separation. Since isolated terminals and denervated electrocytes show normal ultrastructural characteristics for up to 12 h, the skate electric organ provides several preparations which are not attainable with Torpedo tissue. Acetylcholine (ACh) content of supernatant fractions containing the synaptosomes was comparable to that found in Torpedo (sps.). Collagenase specifically eliminates the basal lamina associated with the synaptic junctional region. Neuronal cell death and synaptic terminal degeneration were also noted in the adult organs of both species. The skate electric organ is ideally suited for the study of cholinergic development and transmission.     

Single sperm typing demonstrates that reduced recombination is associated with the production of aneuploid 24,XY human sperm

To account for the increased proportion of paternal nondisjunction in 47,XXY males as compared to other trisomies, it has been suggested that the XY bivalent, with its reduced region of homology, is particularly susceptible to nondisjunction. Molecular studies of liveborn Klinefelter syndrome (47,XXY) individuals have reported an association between the absence of recombination in the pseudoautosomal region and nondisjunction of the XY bivalent. In this study we examined single sperm from a normal 46,XY male to determine if there is any alteration in the recombination frequency of aneuploid disomic 24,XY sperm compared to unisomic sperm (23,X or Y). Two DNA markers STS/STS pseudogene and DXYS15 were typed in sperm from a heterozygous man to determine if recombination had occurred in the pseudoautosomal region. Individual unisomic sperm (23,X or Y) were isolated using a FACStar(Plus) flow cytometer into PCR tubes. To identify disomic 24,XY sperm, 3-colour FISH analysis was performed with probes for chromosomes X,Y and 1. The 24,XY cells were identified using fluorescence microscopy, each disomic sperm was scraped off the slide using a glass needle attached to a micromanipulator and then put into a PCR tube. Hemi-nested PCR analysis of the two markers was performed to determine the frequency of recombination. A total of 329 unisomic sperm and 150 disomic sperm have been typed. The frequency of recombination between the two DNA markers was 38.3% for the unisomic sperm, similar to frequencies previously reported. The 24,XY disomic sperm had an estimated recombination frequency of 25.3%, however, a highly significant decrease compared to the unisomic 23,X or 23,Y sperm (chi(2) = 10.7, P = 0.001). This direct analysis of human sperm indicates that lack of recombination in the pseudoautosomal region is a significant cause of XY nondisjunction and thus Klinefelter syndrome. Copyright Wiley-Liss. Inc.