Lack of correlation between expression of Epstein-Barr virus (EBV) latent membrane protein and bcl-2 oncoprotein in vivo.

AIMS--To evaluate whether there is any correlation between the expression of Epstein-Barr virus (EBV) latent membrane protein (LMP) and oncoprotein bcl-2 in the lymph node biopsy specimens of a Chinese patient with EBV-related reactive lymphoproliferation who later developed T cell lymphoma after a short period of time. METHODS--Immunohistochemistry, with a standard alkaline phosphatase antialkaline phosphatase (APAAP) method and New Fuchsin as a chromogen, was used for single staining of bcl-2 or LMP. Double immunostaining combining APAAP and indirect immunofluorescence was performed for dual labelling of LMP and bcl-2. RESULTS--bcl-2 was expressed in 10-30% of cells in the first lymph node biopsy specimen (EBV-associated lymphoproliferative disorder) and 30-50% of cells in the second lymph node biopsy specimen (T cell lymphoma). LMP was expressed in the first biopsy specimen but not in the second. Double immunostaining results showed that around 78% of LMP positive cells were bcl-2 negative and 94% bcl-2 positive cells were LMP negative. Among the very small fraction of LMP and bcl-2 double positive cells, the intensity of bcl-2 staining was heterogeneous and was not always stronger than that observed in LMP negative bcl-2 positive cells. CONCLUSIONS--The expression of bcl-2 protein is independent of LMP protein status in vivo. Several mechanisms may be involved in EBV associated lymphomagenesis, and bcl-2 induction may occur independently of LMP expression.     

The influence of normal human ageing on automatic movements

There is evidence that aged normal subjects have more difficulty in achieving automaticity than young subjects. The underlying central neural mechanism for this phenomenon is unclear. In the present study, functional magnetic resonance imaging (fMRI) was used to investigate the effect of normal ageing on automaticity. Aged healthy subjects were asked to practice self-initiated, self-paced, memorized sequential finger movements with different complexity until they could perform the tasks automatically. Automaticity was evaluated by having subjects perform a secondary task simultaneously with the sequential movements. Although it took more time, most aged subjects eventually performed the tasks automatically at the same level as the young subjects. Functional MRI results showed that, for both groups, sequential movements activated similar brain regions before and after automaticity was achieved. No additional activity was observed in the automatic condition. While performing automatic movements, aged subjects had greater activity in the bilateral anterior lobe of cerebellum, premotor area, parietal cortex, left prefrontal cortex, anterior cingulate, caudate nucleus and thalamus, and recruited more areas, including the pre-supplementary motor area and the bilateral posterior lobe of cerebellum, compared to young subjects. These results indicate that most healthy aged subjects can perform some complex motor tasks automatically. However, aged subjects appear to require more brain activity to perform automatically at the same level as young subjects. This appears to be the main reason why aged subjects have more difficulty in achieving automaticity.     

肿瘤光动力治疗中组织氧含量的动态模型研究

目的：分析肿瘤光动力治疗中的组织氧含量的变化规律，研究影响肿瘤光动力治疗效果的与氧相关的因素,探讨改进光动力治疗的途径。方法：建立肿瘤光动力治疗中氧含量的动态模型，并采用Crank—Nicolson离散方法解析该模型，在时间域和空间域上，分析光动力过程中肿瘤氧含量的动态变化过程，研究光照的光功率密度、肿瘤初始氧含量等因素对光动力疗效的影响，并比较间断光照和连续光照两种方式的不同疗效。结果：肿瘤氧含量随着治疗时间和离血管的距离呈衰减趋势，光动力反应只发生在血管附近的有限区域，且区域大小与初始氧含量密切相关．在较高的初始氧含量下，更大区域的氧含量因为处于阈值Cth以上，所以能发生光动力反应。当采用较低的光功率密度光照治疗时,肿瘤氧含量衰减比高功率密度下慢；当采用间断光照进行光动力治疗时，在治疗黑暗期肿瘤氧含量能得到回升．有利于光照期的治疗。结论：初始氧含量较高的情况下治疗效果更好；在较低的光功率密度下，光动力反应较难进行，但是有利于保护肿瘤供氧源的工作。在较低的初始氧含量下，间断光照方式的疗效要比连续光照要好。     

Self-assembled biomimetic monolayers using phospholipid-containing disulfides

Several phospholipid-based disulfide molecules were synthesized and attached onto the gold-coated silicon wafer using the self-assembling method. The syntheses of these surface-modifying agents were conducted by introducing bromoethylphosphorate (PBr), phosphorylcholine (PC) or phosphorylethanolamine (PE) groups on the terminals of a dialkyl disulfide. After disulfides adsorption onto gold substrate surfaces, the composition, the film thickness, and the conformational order of self-assembled monolayer surfaces were explored and discussed in detail based on reflection-absorption infrared spectroscopy, contact angle measurement, Auger electron spectroscopy, X-ray photoelectron spectroscopy, and so on. The monolayer having the PBr end group could also be converted to a PC surface by treating with trimethylamine. The model functional surfaces of Au-SC11-PC, -PE, -PBr, -OH or corresponding mixed layers were used to mimic biomembrane surfaces. The monolayer having PC groups was found to reduce fibrinogen adsorption as evaluated from protein adsorption experiments using quartz crystal microbalance. It also showed relatively low platelet adherence compare to the glass, PBr and PE surfaces. The cell viability test also revealed that the PC surface displayed lower cytotoxicity than other surfaces.     

大鼠孤束核内NT-LI成分生后发育和衰老变化的光镜和电镜观察

用免疫细胞化学和电镜相结合技术,在光镜和电镜水平对生后4天、15天、30天、90天、300天和760天6组大鼠孤束核内神经降压肽样免疫反应(NT-LI)成分的生后发育和衰老变化进行了定量研究。光镜下孤束核内NT-LI胞体和终末主要分布于最后区平面,多见于背侧亚核、内侧亚核和连合核内。电镜下内侧亚核内可见NT-LI胞体、树突、轴突及终末。6组大鼠孤束核内NT-LI细胞均数和内侧亚核内NT-LI终末密度及其突触密度均以生后4天至15天间增长最快,NT-LI细胞数在生后15天达到最高,NT-LI终末及突触密度在生后90天达到最高。三者在生后300天时均明显减少。发育期内侧亚核内NT-LI终末构成的突触以Gray Ⅰ型为主,至老年期则变为Gray Ⅱ型占优势。发育期内侧亚核内以含清亮囊泡伴颗粒囊泡的NT-LI终末为主,老年期此类终末明显减少。只含清亮囊泡的NT-LI终末从生后至老年变化不明显。     

重组人免疫缺陷病毒Ⅰ型逆转录酶的纯化及其动力学性质

目的纯化重组人免疫缺陷病毒Ⅰ型逆转录酶（ＨＩＶ－１ＲＴ），筛选新的ＨＩＶ－１ＲＴ抑制剂。方法在适宜的培养条件下诱导工程菌Ｅ．ｃｏｌｉＪＭ１０９（ＰＫＲＴ２）可高效表达重组人免疫缺陷病毒Ⅰ型（ＨＩＶ－１）逆转录酶（ＲＴ）。应用ＤＥＡＥ－纤维素和磷酸纤维素离子交换柱层析法从细菌裂解液中分离、纯化重组ＲＴ。结果１升细菌培养液可得到１．１ｍｇ产物。ＳＤＳ－聚丙烯酰胺凝胶电泳分析显示所纯化的重组ＲＴ为由两个分子量分别为６６ｋＤ和５１ｋＤ的亚基组成的杂二聚体。酶活性测定结果表明，经纯化的重组ＲＴ具有很高的逆转录酶活性（比活力为１．４×１０４ｕｍｇ）。结论本文通过对ＲＴ反应条件的研究，优化了ＲＴ反应系统，并测定了磷甲酸钠（ＰＦＡ）对重组ＲＴ的抑制效应，结果表明ＰＦＡ对重组ＲＴ的抑制反应动力学机制与天然ＲＴ相同，从而进一步说明用此法纯化的重组ＲＴ可直接用于抗ＨＩＶ药物的筛选与评价。     

Mouse homologues of the human AZF candidate gene RBM are expressed in spermatogonia and spermatids, and map to a Y chromosome deletion interval associated with a high incidence of sperm abnormalities

An RNA-binding motif (RBM) gene family has been identified on the human Y chromosome that maps to the same deletion interval as the 'azoospermia factor' (AZF). We have identified the homologous gene family (Rbm) on the mouse Y with a view to investigating the proposal that this gene family plays a role in spermatogenesis. At least 25 and probably >50 copies of Rbm are present on the mouse Y chromosome short arm located between Sry and the centromere. As in the human, a role in spermatogenesis is indicated by a germ cell-specific pattern of expression in the testis, but there are distinct differences in the pattern of expression between the two species. Mice carrying the deletion Yd1, that maps to the proximal Y short arm, are female due to a position effect resulting in non-expression of Sry ; sex-reversing such mice with an Sry transgene produces males with a high incidence of abnormal sperm, making this the third deletion interval on the mouse Y that affects some aspect of spermatogenesis. Most of the copies of Rbm map to this deletion interval, and the Yd1males have markedly reduced Rbm expression, suggesting that RBM deficiency may be responsible for, or contribute to, the abnormal sperm development. In man, deletion of the functional copies of RBM is associated with meiotic arrest rather than sperm anomalies; however, the different effects of deletion are consistent with the differences in expression between the two species.      

How self-initiated memorized movements become automatic: a functional MRI study

We used functional magnetic resonance imaging (fMRI) and dual tasks to investigate the physiology of how movements become automatic. Normal subjects were asked to practice some self-initiated, self-paced, memorized sequential finger movements with different complexity until they could perform the tasks automatically. Automaticity was evaluated by having subjects perform a secondary task simultaneously with the sequential movements. Our secondary task was a letter-counting task where subjects were asked to identify the number of times a target letter from the letter sequences was seen. Only the performances that achieved high accuracy in both single and dual tasks were considered automatic. The fMRI results before and after automaticity was achieved were compared. Our data showed that for both conditions, sequential movements activated similar brain regions. No additional activity was observed in the automatic condition. There was less activity in bilateral cerebellum, presupplementary motor area, cingulate cortex, left caudate nucleus, premotor cortex, parietal cortex, and prefrontal cortex during the automatic stage. These findings suggest that most of the motor network participates in executing automatic movements and that it becomes more efficient as movements become more automatic. Our results do not provide evidence for any area to become more activated for automatic movements.