Biomimetic deposition of apatite coating on surface-modified NiTi alloy

TiO(2) coatings were prepared on NiTi alloy by heat treatment in air at 300, 400, 600 and 800 degrees C. The heat-treated NiTi alloy was subsequently immersed in a simulated body fluid for the biomimetic deposition of the apatite layer onto the surface of TiO(2) coating. The apatite coatings as well as the surface oxide layer on NiTi alloy were characterized using scanning electron microscopy equipped with energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy. Results showed the samples heat-treated at 600 degrees C produced a layer of anatase and rutile TiO(2) on the surface of NiTi. No TiO(2) was detected on the surface of NiTi after heat treatment at 300 and 400 degrees C by X-ray diffraction, while rutile was formed on the surface of the 800 degrees C heat-treated sample. It was found that the 600 degrees C heat-treated NiTi induced a layer consisted of microcrystalline carbonate containing hydroxyapatite on its surface most effectively, while 300 and 400 degrees C heat-treated NiTi did not form apatite. This was due to the presence of anatase and/or rutile in the 600 and 800 degrees C heat-treated NiTi which could provide atomic arrangements in their crystal structures suitable for the epitaxy of apatite crystals, and anatase had better apatite-forming ability than rutile. XPS and Raman results revealed that this apatite layer was a carbonated and non-stoichiometric apatite with Ca/P ratio of 1.53, which was similar to the human bone. The formation of apatite on 600 degrees C heat-treated NiTi following immersion in SBF for 3 days indicated that the surface modified NiTi possessed excellent bioactivity.     

人和大鼠腰椎关节突关节的SP能神经纤维的分布

目的：证实支配腰椎关节突关节的神经支配和化学性质，方法：用逆行荧光素标记结合免疫组化法，研究７只大鼠腰部脊神经节细胞的周围突分支投射到腰椎关节突关节及其递质性质以及３例人腰椎关节突关节囊上神经末梢的化学性质，结果：发现大鼠一侧Ｌ５和Ｌ６之间的关节突关节受同侧Ｌ２－５节段的脊神经节的部分细胞周围突分支支配，其中有３３．３９９％的中型和小型细胞为中ＳＰ能免疫反应阳性，人的关节突关节囊含有ＳＰ阳性的神经     

老年学习记忆减退大鼠齿状回突触的定量研究

据老年大鼠在Ｍｏｒｒｉｓ水迷宫中的行为表现，将其分为老年学习记忆减退和学习记忆正常两部分，采用透射电镜观察、拍片，对齿状回中分子层触的数量和大小进行体视学定量分析。     

Five novel mutations in the L1CAM gene in families with X linked hydrocephalus.

Five novel mutations have been identified in the gene encoding L1CAM, a neural cell adhesion protein, in families with X linked hydrocephalus (XHC). Interestingly, all five mutations are in the evolutionarily highly conserved Ig-like domains of the protein. The two frameshift mutations (52insC and 955delG) and the nonsense mutation (Trp276Ter) most probably result in functional null alleles and complete absence of L1CAM at the cell surface. The two missense mutations (Tyr194Cys and Pro240Leu) may considerably alter the structure of the L1CAM protein. These data provide convincing evidence that XHC is genetically extremely heterogeneous.     

Acrylic‐Based Polyurethane/Silica Hybrids Prepared by Acid‐Catalyzed Sol–Gel Process: Structure and Mechanical Properties

Summary: Silica sols were first prepared based on different ratios of tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) by an acid‐catalyzed sol–gel process, and then incorporated into acrylic‐based polyurethanes. The structures and morphologies of silicone‐oxo clusters were studied by ²⁹Si NMR, SAXS, and scanning electron microscopy (SEM), whereas the mechanical properties of polyurethane/silica hybrids were characterized by DMA and tensile tests. The silicone‐oxo clusters in both silica sol and polyurethane hybrids became denser and larger at a higher molar ratio of TEOS/MTES and higher silica content, and the silica‐oxo clusters of polyurethane/silica hybrids even became more compact and larger than those of silica sols, increasing the elastic modulus and tensile strength of polyurethane/silica hybrids.

Typical structure of silica sol prepared from the hydrolysis and condensation of TEOS and MTES with acid as the catalyst.     

中药“神经再生素”促神经生长过程中基因差异性表达的初步研究

为了探索中药“神经再生素”促神经生长过程中基因水平的变化。本实验采用 dd-PCR方法 ,从体外培养背根神经节细胞加药组和不加药组中获得两者的差异表达片段 ,并经反杂交筛选、克隆测序、DNA序列检索分析、Northern验证。结果表明 ,差异显示共获得 8个差异条带 ,一个为下调基因 ,其余为上调基因 ,其中 2个 c DNA序列与 RRAJ5 16 1基因 (增殖相关基因 )、AF196 3 15基因 (锌指样蛋白 DDP2 ) 10 0 %同源 ,2个 c DNA序列与 AK0 0 175 7基因、STA5 SRR基因 (t RNA合成酶 )部分同源。结论是中药“神经再生素”在促神经生长过程中 ,对神经元基因的选择性表达起着重要的调控作用。     

巨噬细胞源性神经营养因子的初步分离

本文制备了巨噬细胞条件培养基（ＭφＣＭ），并应用快速自动比色微量分析法检测ＭφＣＭ对体外培养的生后７ｄＳＤ大鼠小脑皮质神经元的作用。结果表明，分子量大于１０ｋＤ的ＭφＣＭ对神经元（细胞密度１×１０６／ｍｌ）的作用，与对照组比较有明显的神经营养活性（Ｆ＜０．０５）；用盖玻片培养法表明，该组份有促进神经元突起生长的作用。ＭφＣＭ经ＳｅｐｈａｃｒｙｌＳ－１００－ＨＲ凝胶层析和生物活性鉴定，获得了具有神经营养活性的第二峰洗脱液。此洗脱液经ＳＤＳ－聚丙烯酰胺凝胶电泳分析，证明ＭφＣＭ中神经营养活性成份的蛋白质其分子量为３１ｋＤ－６８ｋＤ之间。     

近代甲状腺功能检查新策略的初步临床评估

本文观察研究了九组共263例循环血TT4、TT3、FT4、TF3，经数理统计和临床综合分析判断，这些测定值生理，病理含义，临床价值不尽雷同。TT4、TT3是现今临床甲状腺功能检验常用，多用、频用的方法，仍不失为一种金试验。FT4、FT3测定方法灵敏，方法学上仍有争论，TT4、TT3留存的临床问题，FT4、FT3亦常存在，且易发生；FT4、FT3试剂盒价贵，在价格论——效益分析上也应商榷。当前我国临床应用策略上似仍以TT4、TT3、FT3、s-TSH；甲状腺疾病；非甲状腺疾病。     

Long-term regulation of N-methyl-D-aspartate receptor subunits and associated synaptic proteins following hippocampal synaptic plasticity

Synaptic plasticity in the dentate gyrus is dependent on activation of the N-methyl-D-aspartate (NMDA)-subtype of glutamate receptors. In this study, we show that synaptic plasticity in turn regulates NMDA receptors, since subunits of the NMDA receptor complex are bidirectionally and independently regulated in the dentate gyrus following activation of perforant synapses in awake animals. Low-frequency stimulation that produced a mild synaptic depression resulted in a decrease in the NMDA receptor subunits NR1 and NR2B 48 h following stimulation. High-frequency stimulation that produced long-term potentiation resulted in an increase in NR1 and NR2B at the same time point. Further investigations revealed that in contrast to NR2B, NR1 levels increased gradually after long-term potentiation induction, reaching a peak level at 48 h, and were insensitive to the competitive NMDA receptor antagonist 3-3(2-carboxypiperazin-4-yl) propyl-1-phosphate. The increased levels of NR1 and NR2B at 48 h were found associated with synaptic membranes and with increased NMDA receptor-associated proteins, postsynaptic density protein 95, neuronal nitric oxide synthase and Ca(2+)/calmodulin-dependent protein kinase II, alpha subunit. These data suggest that the persistence of long-term potentiation is associated with an increase in the number of NMDA receptor complexes, which may be indicative of an increase in synaptic contact area.     

Myxobolus sp., another opportunistic parasite in immunosuppressed patients?

During a study of intestinal parasitic infections in human immunodeficiency virus-positive patients, a parasite belonging to the phylum Myxozoa, recently described from human samples, was identified in one sample. When this parasite was stained by the modified Ziehl-Neelsen staining method, the features of the spores were identified: they were pyriform in shape, had thick walls, and had one suture and two polar capsules, with each one having four or five coils. The suture and two polar capsules were observed with the chromotrope-modified stain. The number of stools passed was more than 30 per day, but oocysts of Isospora belli were also found. Upon reexamination of some formalin- or merthiolate-iodine-formaldehyde-preserved samples an identical parasite was found in another sample from a patient presenting with diarrhea. Strongyloides stercoralis larvae and eggs of Hymenolepis nana and Ascaris lumbricoides were also found in this sample. Given that both patients were also infected with other pathogens that cause diarrhea, the possible pathogenic role of this parasite could not be established. The probable route of infection also could not be established.