Influences of simulated gastrointestinal environment on physicochemical properties of gold nanoparticles and their implications on intestinal epithelial permeability

Gold nanoparticles (Au NPs) hold great promise in food, industrial and biomedical applications due to their unique physicochemical properties. However, influences of the gastrointestinal tract (GIT), a likely route for Au NPs administration, on the physicochemical properties of Au NPs has been rarely evaluated. Here, we investigated the influence of GIT fluids on the physicochemical properties of Au NPs (5, 50, and 100?nm) and their implications on intestinal epithelial permeability in vitro. Au NPs aggregated in fasted gastric fluids and generated hydroxyl radicals in the presence of H₂O₂. Cell studies showed that GIT fluids incubation of Au NPs affected the cellular uptake of Au NPs but did not induce cytotoxicity or disturb the intestinal epithelial permeability.     

Platelets in Early Antibody-Mediated Rejection of Renal Transplants

Antibody-mediated rejection is a major complication in renal transplantation. The pathologic manifestations of acute antibody-mediated rejection that has progressed to functional impairment of a renal transplant have been defined in clinical biopsy specimens. However, the initial stages of the process are difficult to resolve with the unavoidable variables of clinical studies. We devised a model of renal transplantation to elucidate the initial stages of humoral rejection. Kidneys were orthotopically allografted to immunodeficient mice. After perioperative inflammation subsided, donor-specific alloantibodies were passively transferred to the recipient. Within 1 hour after a single transfer of antibodies, C4d was deposited diffusely on capillaries, and von Willebrand factor released from endothelial cells coated intravascular platelet aggregates. Platelet-transported inflammatory mediators platelet factor 4 and serotonin accumulated in the graft at 100- to 1000-fold higher concentrations compared with other platelet-transported chemokines. Activated platelets that expressed P-selectin attached to vascular endothelium and macrophages. These intragraft inflammatory changes were accompanied by evidence of acute endothelial injury. Repeated transfers of alloantibodies over 1 week sustained high levels of platelet factor 4 and serotonin. Platelet depletion decreased platelet mediators and altered the accumulation of macrophages. These data indicate that platelets augment early inflammation in response to donor-specific antibodies and that platelet-derived mediators may be markers of evolving alloantibody responses.     

使用棱镜重新定位双侧中心暗点患者视网膜物像的预试验

目的 本研究使用激光扫描检眼镜(SLO)评价双侧中央暗点患者使用棱镜后的眼球运动反应.方法 本预试验共招募6例有双侧中央暗点的年龄相关性黄斑变性(AMD)患者以及6例正常视力的志愿者.首先用Nidek MP-1微视野仪确认患者的中央暗点和优选视网膜注视点(PRL),然后用Rodenstock SLO,在将视标投射在优选视网膜注视点时拍下实时视网膜像,接着在受检者眼前加入6～8 PD的棱镜,要求受检者保持注视视标,这时通过视网膜标记来测量视网膜像的移位量,以及随后发生的优选视网膜注视点的再次注视.过程中平均移位量和再次注视时间通过图像软件(ImageJ software)来计算.结果 实验组再次注视时的移位量在3个像素点或11.66个弧分之内(x轴:2.90±3.92,y轴:2.53±4.18).对照组再次注视时的移位会准确些(x轴:0.33±1.15,y轴:0.89±2.50),但与实验组差异无统计学意义(tx=1.32,Px＞0.05;ty=0.80,Py＞0.05).对照组再次注视时间(0.98±0.19)s较实验组(2.83±1.63)s要短,差距有统计学意义(t=5.03,P＜0.01).其中有1例实验组受检者没有发生再次注视,其结果被排除并单独分析.结论 研究发现,双眼中央暗点患者对棱镜物像转移后的再注视反应与正常人接近,但实验组再注视明显较对照组慢,并有1例受检者没有发生再注视.该数据说明双侧中央暗点患者无论眼前有没有棱镜,都会利用相同的视网膜位置视物,因此,通过棱镜物像再定位的意义不大.     

电子线照射对小鼠胰岛素生长因子相关蛋白表达的影响

目的：探讨电子线对胰岛素生长因子-1家族蛋白表达的影响，为研究辐射对肝脏的早期损伤提供依据。方法：采用电子线照射小鼠，照射剂量为1、2、4 Gy，用Western blot法检测照射后12、48和72 h小鼠肝脏中胰岛素生长因子1受体（IGF-1R）、胰岛素生长因子结合蛋白1（IGFBP1）、胰岛素生长因子结合蛋白4（IGFBP4）和胰岛素生长因子1（IGF-1）蛋白表达水平的改变。结果：照射剂量为1 Gy时，与对照组相比，IGF-1蛋白在照射后48 h时表达增加，IGFBP1、IGFBP4和IGF1R蛋白的表达在照射后12、48和72 h均表达减少。照射剂量为2 Gy时，IGF-1和IGFBP4蛋白在照射后48 h时表达增加，其余时间点表达减少。IGFBP1蛋白在照射后12 h时表达增加，48和72 h时表达减少。IGF1R蛋白在照射后3个时间点均呈现为表达减少。照射剂量4 Gy时，肝脏中IGF-1、IGFBP1和IGFBP4蛋白均表达减少，IGF1R蛋白在照射后12 h时表达增加，48、72 h时均表达减少（均为P < 0.05）。结论：电子线照射后小鼠肝脏中胰岛素生长因子-1家族蛋白多以下调表达为主，与前期基因表达的结果相一致，有可能作为反映放射性工作人员早期肝脏损伤的生物标志物之一。     

亚麻籽胶的胶凝性质

采用流变学法测定了亚麻籽胶溶液的胶凝点、熔化点，并采用质构仪、扫描电镜和原子力显微镜等手段研究了影响亚麻籽胶凝胶强度的因素，结果表明亚麻籽胶具有胶凝性，它能形成一种热可逆的冷致凝胶，亚麻籽胶溶液的胶凝点低于其凝胶的熔化点，且亚麻籽胶溶液的胶凝点及其凝胶的熔化点均随冷却的起始温度的升高而升高。亚麻籽胶浓度、溶解温度、pH、NaCl、CaCl2及复合磷酸盐能影响亚麻籽胶的凝胶强度，亚麻籽胶的凝胶强度随着浓度的增加及溶解温度的升高而增强；在pH6～9的范围内，亚麻籽胶的凝胶强度达到最大；NaCl和复合磷酸盐可以降低亚麻籽胶的凝胶强度，低浓度（〈0．3％）的CaCl2可以增强亚麻籽胶的凝胶强度，而高质量分数（〉0．3％）的CaCl2能降低亚麻籽胶的凝胶强度。     

Ultrastructural detection of neuronally transported choleragenoid by postembedding immunocytochemistry in freeze-substituted Lowicryl HM20™ embedded tissue

Choleragenoid (cholera toxin B-fragment; CTB) is an anterograde, retrograde and transganglionic neuronal tracer. We describe a method for detecting CTB-labeled neuronal cell bodies, neurites and boutons at the ultrastructural level, using postembedding immunogold techniques on freeze-substituted Lowicryl HM20™ embedded nervous tissue. Primary afferents and motoneurons were labeled by injection of CTB in the dorsal ramus of the C2 spinal nerve of the rat. Following fixation with paraformaldehyde (4%) and glutaraldehyde (0.25%), tissue sections from the spinal cord C2 segment were freeze-substituted and embedded in Lowicryl HM20™ and subsequently processed with postembedding immunocytochemistry for CTB and glutamate. Immunogold particles indicating CTB immunoreactivity were found over primary afferents and motoneurons. In primary afferents in the central cervical nucleus (CCN) and motor nuclei, immunogold labeling was seen in boutons over vesicle-containing axoplasm and to a lesser extent over axoplasm devoid of vesicles, but not over mitochondria or axolemma. In motoneurons, immunogold particles were seen over the Golgi apparatus in the soma and over lysosomes in both soma and dendrites. Quantification of glutamate-like immunoreactivity in 20 CTB-labeled and 20 CTB-negative boutons in the neuropil was found similar, indicating that CTB does not interfere with the immunocytochemical detection of neuronal epitopes such as the transmitter substance glutamate.     

小儿特发性血小板减少性紫癜发病机制的研究

本文采用体外建立抗原—抗体—补体反应体系的试验方法,通过测定该反应体系的血小板~(51)Cr 释放量来进一步探讨特发性血小板减少紫癜(ITP)患儿血小板的破坏机制。结果45例ITP 惠儿其血小板~(51)Cr 释放量与正常值比较明显增高(P<0.01),急慢性之问无显著差异性。45例患儿中有31例血小板~(51)Cr释放量高出正常值上限。同时观察ITP 患儿血清对血小板超微形态和结构的影响,发现血小板表面有圆钝伪足形成,血小板聚集,血小板脱颗粒和空泡性变。正常儿血清对血小板超微形态和结构无明显影响。作者认为,ITP 患儿的血小板相关抗体,能介导血管内血小板的溶解与破坏,其既影响血小板数量,又改变血小板的结构,二者都是导致该病出血的重要原因。     

电镜下的乙型肝炎表面抗原

本文对81例乙型肝炎病人的肝活检组织进行了电镜观察,发现HBsAg的阳性率达93.8％。电镜下,HBsAg细丝不仅有一般的管状细丝型,还有分枝管型和管泡型,而且CAH病人肝组织不易找到HBsAg丝(易见者仅9％),CPH,CLH则多数(79.5％)为易见及可见,二者有高度显著性差异(P<0.01)。     

电子直线加速器照射对NIH 3T3细胞的细胞周期及凋亡的影响

目的 探讨电子直线加速器照射对细胞周期及细胞凋亡的影响。方法 采用直线加速器对NIH 3T3细胞进行照射，观察细胞周期及细胞凋亡的改变情况；同时测定损伤前后p53蛋白的表达情况。结果 照射后细胞凋亡数增加，p53蛋白表达量上升。结论 电子直线加速器照射损伤可诱导细胞凋亡。     

甲氧苄氨嘧啶—PVP共沉淀物的研究

本工作用差示扫描量热法(DSC)研究甲氧苄氨嘧啶与PVP溶剂法制备的共沉淀物,表明已不存在甲氧苄氨嘧啶晶体。用x射线衍射法研究了1:12共沉淀物,证明无甲氧苄氨嘧啶的晶体衍射峰。经分光光度法测定结果,1:12共沉淀物比原药的溶解度大28.3倍。