Nacre surface transformation to hydroxyapatite in a phosphate buffer solution

Nacre, also known as mother-of-pearl, constitutes the inner layer of mollusc shells. Nacre is a natural composite material consisting mostly of calcium carbonate in the aragonite crystal form and some organic matter. Previous studies have shown that geological aragonite, coral and nacre can convert hydrothermally to hydroxyapatite (HAP) in phosphate solution by a solid-state topotactic ion-exchange reaction. This conversion typically occurs within the range of 140-260 degrees C, although higher temperatures are possible. In this work, we have found that nacre can transform to HAP in a phosphate buffer solution at room temperature via a surface reaction. The morphology of the nacre-transformed HAP surface was investigated by scanning electron microscopy (SEM). The HAP surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). A layer covered with packed particles was found in contrast to the tablet structure typical of nacre surfaces. XPS and SIMS indicated that the mineral phase of the nacre surface had converted from an aragonite phase to an HAP phase. Fourier transform infrared spectroscopy (FTIR) showed that phosphate (PO(4)) bands appeared after nacre was soaked in a phosphate buffer and the intensity of the PO(4) bands increased with exposure time. The FTIR was consistent with XPS and SIMS results. We suggest that this surface reaction occurs by a dissolution-precipitation mechanism. Calcium ions are released from the nacre surface, react with phosphate ions in the buffer solution, and then precipitate as HAP on the nacre surface.     

几个常用执行功能测验在抑郁症中的应用

本文回顾了几个常用执行功能测验在抑郁症研究中的应用情况,包括威斯康星卡片分类测验（WCST）、Stroop色词测验、连线测验（TMT）、Go/no go任务,以及N-back任务。另外,对已有研究中存在的问题进行了讨论和展望。     

凝血酶对人重组内皮细胞衍生IL—8融合蛋白转换作用

本文报道利用基因工程技术在大肠杆菌中表达出入内皮细胞衍生IL-8(EDhIL-8)与细菌蛋白lacZ 的融合蛋白lac-hIL-8和lac-T-hIL-8,后者含有一个人工合成凝血酶切点。EDhIL-8上含有一个凝血酶切点,凝血酶可以将lac-hIL-8及以前表达的MS2-hIL-8水解为有生物活性的天然IL-8,而对含有两个凝血酶切点的lac-T-hIL-8无水解作用。这些结果提示凝血酶的功能不仅依赖于所识别的氨基酸,而且依赖于这些氨基酸形成的构象。     

强迫症患者认知功能与病期的关系

目的：探讨强迫症的认知功能障碍与病期的关系。方法：分别用韦氏记忆测验，数字划销测验和威斯康星卡片分类测验评估25例急性强迫症和36例慢性强迫症患者的记忆、注意和执行功能。结果：急性强迫症患者的记忆测验中记图和数字划销测验中第二阶段失误率显著性较慢性强迫症差，其余两组间记忆测验、划销测验和威斯康星卡片分类测验各量表分无显著性差异。结论：强迫症的认知功能与病期无明显相关。     

Influence of growth hormone-insulin-like growth factor Ⅰ axis on normal pregnancy

Objective To investigate the role of growth hormone-insulin-like growth factor Ⅰ (IGF-Ⅰ) axis in normal pregnancy. Methods Totally, 116 normal pregnant women were recruited from January 1997 to June 1998, with 20 normal nonpregnant women as controls. Maternal growth hormone (GH) and IGF-Ⅰ concentrations were assayed by RIA and enzyme-linked immunosorbent assay, respectively. Results Maternal serum levels of GH increased throughout gestation, reached a peak at 25 weeks of pregnancy and remained fairly high (χ[2]=40.458, P<0.0001).There was a significant difference between samples at 5-9 week gestational age and the controls (3.45 μg/L vs 1.61 μg/L, P<0.05). The maternal serum levels of IGF-Ⅰincreased rapidly throughout gestation from 29-week gestation and reached a peak of 188.86 μg/L at term delivery (χ[2]=50.224, P<0.0001). Conclusions Maternal GH levels increased progressively throughout gestation, which correlated with fetal growth. Maternal GH may regulate nutrition supply among mother, placenta and the fetus and play an important role in transporting nutritional substrates by the placenta. The maternal IGF-Ⅰin the third trimester may promote fetal growth and placental functions.     

阴道炎患者HPV6/11-DNA定量分析

目的：了解女性阴道炎患者人乳头瘤病毒6／11型（HPV6／11）的感染情况。方法：荧光定量聚合酶链反应（FQ－PCR）技术检测258例门诊患者阴道分泌物中HPV6／11的病毒拷贝数。结果：共检出HPV6／11阳性者94例,阳性率36．43％,拷贝数在10^5以上者78例,占阳性者中82．98％,40岁以上年龄组阳性率高且病毒复制量均在10^5以上。结论：（1）中老年阴道炎患者就诊晚,感染重。（2）FQ－PCR检测HPV敏感,快速,准确,特别是其定量特点对临床很有意义。     

三味中药配伍应用对改善烫伤小鼠受损免疫功能的作用

目的　观察对烫伤小鼠受损免疫功能具有调理作用的单味中草药 ,经过配伍应用后的协同作用。方法　采用 1 .0 3 4× 1 0 5 Pa的蒸气烫伤 1 0s ,烫伤面积 1 6% ,深度为Ⅲ度的致伤模型烫伤动物。通过观察MΦ的吞噬功能、枯否细胞清除能力、MΦ抗原提呈功能、血清TNF量、淋巴细胞增殖反应及IL 2产生能力、小鼠抗体产生能力、PMNH2 O2 释放量及PMN溶菌酶释放量、血清补体的趋化作用和聚集作用等指标 ,籍以了解单味中药与配伍中药对烧 (烫 )伤小鼠受损免疫功能的调理作用。结果　单味中药三七(PP) ,金银花 (LJ)和虎杖 (PC)对小鼠受损免疫功能有一定的改善作用。PC +LJ、PP +PC、PP +LJ等二味配伍的中药 ,除少数指标外 ,均比单味药的作用好。而PP +LJ+PC三味配伍药的调理作用 ,比单味药和二味配伍药的调理作用更佳。结论　单味中药经配伍应用后对烧 (烫 )伤小鼠严重受损的免疫系统功能 ,具有比单味药更好的协同调理作用。     

阉割和睾酮替代对大鼠应激免疫抑制蛋白的影响

目的 :研究阉割和睾酮替代对束缚应激模型大鼠血清中应激免疫抑制蛋白的影响。方法 :成年雄性SD大鼠随机分为正常对照组、假手术组、阉割组、阉割后睾酮替代组。每组 10～ 12只。以上各组随机抽出一半给予束缚应激 ,另一半作为不应激对照。观察各组大鼠血清对ConA诱导的淋巴细胞转化的作用 ,作为反映血清中应激免疫抑制蛋白含量的指标。在离体实验中观察不同浓度的睾酮对淋巴细胞转化的直接作用。结果 :阉割可促进应激大鼠血清中应激免疫抑制蛋白的产生 ,睾酮替代可对抗这一作用。结论 :睾酮可在一定范围内对抗应激免疫抑制蛋白的产生。     

计算机辅助的心血管信号检测和处理系统的研究

【目的】研制一个计算机辅助的心血管信号检测和处理系统。【方法】本系统的硬件设计采用奔腾 Ⅱ / 2 33多媒体微机系统 ,多路模 /数转换器和心电电极、心音传感器、脉搏波传感器及由运算放大器等构成相关的放大器及滤波器。本系统采用可视化编程环境构建系统结构和功能模块设计的方法 ,基于多媒体技术和小波变换原理 ,在 32位Windows平台下 ,利用可视化编程语言VisualC 6 0和多媒体著作工具Authorware等进行系统的软件设计。【结果】本系统能完成心电、心音、脉搏波信号检测和处理 ,并将结果以图、文、声并茂的形式显示、打印或播放 ,还具有病案管理和心音听诊多媒体计算机辅助教学功能。【结论】它是一个新型的多功能心血管信号检测和处理系统。     

IgA肾病患者的扁桃体免疫组织化学观察

目的：了解ＩｇＡ肾病（ＩｇＡ－Ｎ）与扁桃体免疫异常的关系。方法：经肾穿刺活检确诊为ＩｇＡ－Ｎ３１例,以慢性扁桃体炎１６例作对照,扁桃体切除术后运用ＡＢＣ方法对扁桃体组织进行免疫组化标记。结果：两组扁桃体在ＩｇＡ、ＩｇＧ的表达上存在明显的区别,ＩｇＡ－Ｎ患者的扁桃体组织内产生ＩｇＡ的淋巴细胞数显著增加,结论：ＩｇＡ－Ｎ患者存在着扁桃体免疫异常,切除扁桃可预防抗原入浸,消除扁桃体来源的ＩｇＡ,减少循环中的ＩｇＡ免疫复合物形成,进一步使肾小球基底膜区的ＩｇＡ免疫复合物沉积减少。