Petal-like apatite formed on the surface of tricalcium phosphate ceramic after soaking in distilled water

In the present study six types of tricalcium phosphate ceramic were prepared and soaked in distilled water for different periods to investigate whether a surface apatite layer was formed on TCP ceramics or not. X-ray diffractometry (XRD) and Fourier-transformed infrared (FTIR) spectrometer were used to examine the changes in crystalline phases and functional groups of TCP ceramics for different soaking periods. Calcium and phosphate ions released from TCP ceramics during soaking were recorded by atomic absorption analysis and ion-coupled plasma. Results revealed that alphaTCP, alphaTCP/betaTCP mixture (alphabetaTCP) and betaTCP ceramic were gradually dissolved. There was no apatite layer formed on their surface after being immersed in distilled water for different durations of time. Mg-TCP ceramic, tricalcium phosphate doped with Mg ions, exhibited a lower dissolution rate than the other types of TCP ceramics. Apatite crystals were also not formed on the surface of Mg-TCP ceramic when immersed in distilled water. Tribasic calcium phosphate, prepared from wet precipitation method, was converted to betaTCP/HAP (HbetaTCP) or alphaTCP/betaTCP/HAP (HalphabetaTCP) crystalline composition at different sintering temperatures (1,150 degrees C and 1,300 degrees C). The surface apatite layer did not appear on HbetaTCP ceramic after soaking. We observed that petal-like apatite was formed on the HalphabetaTCP ceramic surface after being immersed for 2 weeks. alphaTCP phase of HalphabetaTCP ceramic was not directly converted to apatite during soaking. The surface apatite layer formed on the HalphabetaTCP ceramic surface was due to the precipitation of the calcium and phosphate ions released from alphaTCP dissolution. HAP, which existed in the structure of HalphabetaTCP ceramic, plays a role as apatite-precipitating seed to uptake calcium and phosphate ions. TCP ceramics which lacked alphaTCP and HAP content neither converted to apatite nor formed surface apatite on their surfaces during immersion.     

Universally conserved and yeast-specific U1 snRNA sequences are important but not essential for U1 snRNP function

To study the contribution of the large, 568-nucleotide yeast (Saccharomyces cerevisiae) U1 snRNA to pre-mRNA splicing, we generated mutations in two regions of the molecule and introduced each mutant gene back into yeast as the sole copy of the U1 snRNA gene. We mutagenized the "A loop," a subregion highly conserved in primary sequence in all U1 snRNA molecules analyzed to date. We also mutagenized a portion of the yeast core subdomain, a region conserved in primary and secondary structure among several yeast species but absent from the much smaller metazoan U1 molecule. Surprisingly, mutations in these two regions had little or no effect on growth rate, yet several of them affected an inefficiently spliced reporter gene construct. In addition, combinations of mutants in both regions gave rise to reduced growth rates. Using the latter assay, we confirmed some of the proposed secondary structure of the yeast core domain. The experiments indicate that both regions contribute to U1 snRNP activity but that mutations in a single region do not have a substantial effect on growth rate because U1 snRNP activity is not rate-limiting for growth.     

绝经后骨质疏松大鼠模型的综合评价

利用双能X线骨密度仪、扫描电镜和骨生物力学试验综合评价大鼠去卵巢后的骨骼状况。结果显示：①大鼠卵巢切除后,活体、离体腰椎以及股骨（除R3区）、胫骨近端干骺端（R1区）的离体骨密度显著下降（P＜0.01),离体L5和L6的骨丢失率最大,达13%;②骨小梁减少、变细,连接中断,骨小梁表面有吸收陷窝;③腰椎压缩强度和股骨力学性均下降,前者更明显,腰椎最大压缩力下降率达33.32%。提示：①类似于绝经后妇女,6月龄大鼠在卵巢切除4个月后骨量和骨质量均下降,特别在富含松质骨的部位,如腰椎、股骨远端等;②利用绝经后骨质疏松大鼠模型评价骨质疏松新药的有效性,应包括该新药对骨量、骨结构和骨强度的作用。     

假鹰爪化学成分研究(Ⅱ)

目的：寻找番荔枝科假鹰爪属植物假鹰爪Ｄｅｓｍｏｓ ｃｈｉｎｅｎｓｉｓ抗肿瘤活性成分。方法：采用硅胶柱色谱分离化学成分。根据理化性质及波谱分析等方法鉴定结构。结果：从氯仿萃取物中分离鉴定了７个化合物,分别是ｕｎｏｎ－ａｌ（Ⅰ）,黄芩素－７－甲醚（Ⅱ）,去甲氧杜鹃花素（Ⅲ）,去甲氧杜鹃花素－７－甲醚（Ⅳ）,苯甲酸（Ⅴ）,β－谷甾醇（Ⅵ）和豆甾醇（Ⅶ）。结论：该种植中鉴定的黄酮类化合物均为β－环未取代,     

香青藤的生药鉴定

利用药材性状、显微特征、紫外吸收光谱和薄层层析等鉴别方法对香青藤进行生药鉴定研究 ,为该药材的鉴别和开发利用提供科学依据     

单纯疱疹病毒TK基因介导GCV治疗人RB肿瘤的实验研究

为探讨HSV－TK基因介导的GCV系统对人视网膜母细胞瘤（RB）基因治疗的有效性,利用电穿孔技术把重组逆转录病毒载体pLXSNTK导入包装细胞PA317,筛选出逆转录病毒产生细胞PA317/TK,收获病毒。体外实验：用逆转录病毒感染RB细胞,筛选出含TK基因的RB细胞（RB/TK）,用GCV分别处理RB、RB/TK及不同比例的混合细胞。体内实验：建立人RB裸鼠原位异种移植模型,瘤内注射病毒液后再经GCV处理。结果：体外实验RB/TK细胞对GCV的敏感性显著高于RB细胞,并存在旁观者效应;RB荷瘤裸鼠内TK/GCV系统对RB细胞的生长也有明显的抑制作用。提示HSVTK/GCV系统有望成为人RB肿瘤的基因治疗途径。     

带蒂额肌帽状腱膜复合组织瓣Ⅰ期修复颅底缺损——附3例报告

目的:探讨颅面联合手术后颅底中央区穿通性缺损I期修复重建的新方法.方法:采用带血管蒂的额肌帽状腱膜复合组织瓣修复重建3例颅底恶性肿瘤切除术后颅底中央区组织缺损,其中正中双蒂额肌帽状腱膜复合组织瓣2例,正中双蒂额肌帽状腱膜颅骨瓣1例.取瓣面积可达8cm×15cm左右.结果:用该瓣修复的3例患者无并发症发生.结论:带蒂额肌帽状腱膜复合组织瓣血管恒定、血供好、组织薄、带有硬性支撑并可弯曲成形,取瓣径路与手术切口一致,不影响美观.因此,该组织瓣为修复颅底中央区穿通性组织缺损的一种新方法.     

各种肝病患者血清TGFα含量与肝细胞损害的关系研究

目的 :探讨转化生长因子α(Transforminggrowthfactor aplha ,TGFα)在各种肝病患者中的变化规律及其与肝细胞损害的关系。方法 :采用非平衡竞争性放射免疫法测定 172例各种肝病患者血清中TGFα含量。结果 :慢性中度肝炎、急性黄疸肝炎、慢性重度肝炎、肝硬化失代偿期、原发性肝癌患者血清TGFα含量分别为 12 .12± 7.35pg ml、14.19± 7.30 pg ml、15 74±9 6 5pg ml、16 .0 2± 9.18pg ml、19.89± 9.0 9pg ml,逐渐升高 ,明显高于对照组 6 .86± 0 .89pg ml(P <0 .0 5)。肝硬化失代偿期与代偿期组间差异有显著性 (P <0 .0 5)。结论 :血清TGFα含量明显升高对原发性肝癌的诊断有帮助。TGFα与各种肝病肝细胞的再生、分化、增殖以及损害有一定的关系。     

铅对大鼠肠道神经元和血管平滑肌细胞NOS活性的影响

用β－ＮＡＤＰＨ组织化学方法研究铅对大鼠肠壁肌间神经佾内神经元和血管平滑肌一氧化氮合酶（ＮＯＳ）活性的影响。结果发现：腹腔注射醋酸铅（４０ｍｇ．ｋｇ＾－１）１５ｄ后,大鼠肠道ＮＯＳ阳性神经无元和阳性纤维数量减少,且阳性神经元的形态也有不同程度的改变,肠壁内血管平滑肌ＮＯＳ活性下降。上述变化提示ＮＯ的生成减少可能是铅中毒时腹能的机制之一。     

陵水暗罗活性成分研究

从陵水暗罗(polyalthia nemoralis A.etDC)根的乙醇提取物中分离得到五个化合物。经光谱(UV,IR,¹H-NMR,¹³C-NMR,DEPT和MS)解析和化学反应,分别鉴定为暗罗素(zincpolyanemine,PN1),2-巯基吡啶-N-氧化物铜盐(PN₂),β-谷甾醇(PN₃),β-谷甾醇-β-D-吡喃葡萄糖甙(PN₄)和2-巯基吡啶-N-氧化物-2-S-β-D-吡喃葡萄糖甙(PN₅),其中PN₅为新化合物,PN2为新天然产物。PN1和PN2有较强抗疟、防霉杀菌作用。PN5的抗疟、防霉试验尚在进行中。