中分子尿毒症毒素及其清除技术的研究进展

尿毒症毒素是一大组体内代谢的产物,在肾功能衰竭患者体液中水平明显升高,并与尿毒症毒素代谢紊乱或临床表现密切相关。一般认为中分子尿毒症毒素的分子量在500D-5000D之间。此类物质蓄积可促进尿毒症性心血管病变的发生发展、抑制机体免疫功能、加重患者营养不良等。研究发现,通过高通量透析、血液透析滤过和血液灌流等方法增加中分子尿毒症毒素的清除,可以为患者带来更好的生活质量和长期生存获益。     

尉家小堡遗址石制品的初步研究

山西北部桑干河中游的尉家小堡遗址,是华北地区以细石器加工技术为特征的旧石器时代晚期遗址,石制品岩性以硅质岩和火山角砾岩为主。细石核全部为楔形石核,显示出一套较为成熟而稳定的制坯及剥片工艺,包括软锤修整楔状缘、压制产生细石叶等。石器类型全部为刮削器。5.6%的拼合率说明此处为原地埋藏遗址。通过与同时代桑干河流域的其他遗址石制品的比较和遗址出土较精致的穿孔骨制品的现象判断,此遗址的年代应在旧石器时代晚期之末。     

The G82S polymorphism promotes glycosylation of the receptor for advanced glycation end products (RAGE) at asparagine 81: comparison of wild-type rage with the G82S polymorphic variant

Interaction between the receptor for advanced glycation end products (RAGE) and its ligands amplifies the proinflammatory response. N-Linked glycosylation of RAGE plays an important role in the regulation of ligand binding. Two potential sites for N-linked glycosylation, at Asn(25) and Asn(81), are implicated, one of which is potentially influenced by a naturally occurring polymorphism that substitutes Gly(82) with Ser. This G82S polymorphic RAGE variant displays increased ligand binding and downstream signaling. We hypothesized that the G82S polymorphism affects RAGE glycosylation and thereby affects ligand binding. WT or various mutant forms of RAGE protein, including N25Q, N81Q, N25Q/G82S, and N25Q/N81Q, were produced by transfecting HEK293 cells. The glycosylation patterns of expressed proteins were compared. Enzymatic deglycosylation showed that WT RAGE and the G82S polymorphic variant are glycosylated to the same extent. Our data also revealed N-linked glycosylation of N25Q and N81Q mutants, suggesting that both Asn(25) and Asn(81) can be utilized for N-linked glycosylation. Using mass spectrometry analysis, we found that Asn(81) may or may not be glycosylated in WT RAGE, whereas in G82S RAGE, Asn(81) is always glycosylated. Furthermore, RAGE binding to S100B ligand is affected by Asn(81) glycosylation, with consequences for NF-κB activation. Therefore, the G82S polymorphism promotes N-linked glycosylation of Asn(81), which has implications for the structure of the ligand binding region of RAGE and might explain the enhanced function associated with the G82S polymorphic RAGE variant.     

黑斑蛙的减数分裂研究

本文研究了黑斑蛙的减数分裂,发现其性染色体所形成的性二价体主要呈末端与末端联接,浓缩期占79.6％,中期Ⅰ占75％,这进一步证明黑斑蛙确实存在XY型性别决定机制,这种XY型性染色体虽形态相同,但已发生了质的分化,可能是同型异质。黑斑蛙的性染色体并不形成性泡,少数二价体有中间交叉。     

Enzymatic glycosidation of sugar oxazolines having a carboxylate group catalyzed by chitinase

Enzymatic glycosidation using sugar oxazolines 1-3 having a carboxylate group as glycosyl donors and compounds 4-6 as glycosyl acceptors was performed by employing a chitinase from Bacillus sp. as catalyst. All the glycosidations proceeded with full control in stereochemistry at the anomeric carbon of the donor and regio-selectivity of the acceptor. The N,N'-diacetyl-6'-O-carboxymethylchitobiose oxazoline derivative 1 was effectively glycosidated, under catalysis by the enzyme, with methyl N,N'-diacetyl-beta-chitobioside (4), pent-4-enyl N-acetyl-beta-D-glucosaminide (5), and methyl N-acetyl-beta-D-glucosaminide (6), affording in good yields the corresponding oligosaccharide derivatives having 6-O-carboxymethyl group at the nonreducing GlcNAc residue. The N,N'-diacetyl-6-O-carboxymethylchitobiose oxazoline derivative 2 was subjected to catalysis by the enzyme catalysis; however, no glycosidated products were produced through the reactions with 4, 5, and 6. Glycosidation reactions of the beta-d-glucosyluronic-(1-->4)-N-acetyl-D-glucosamine oxazoline derivative 3 proceeded with each of the glycosyl acceptors, giving rise to the corresponding oligosaccharide derivative having a GlcA residue at their nonreducing termini in good yields.     

Effect of increased convective clearance by on-line hemodiafiltration on all cause and cardiovascular mortality in chronic hemodialysis patients – the Dutch CONvective TRAnsport STudy (CONTRAST): rationale and design of a randomised controlled trial [ISRCTN38365125]

Background

The high incidence of cardiovascular disease in patients with end stage renal disease (ESRD) is related to the accumulation of uremic toxins in the middle and large-middle molecular weight range. As online hemodiafiltration (HDF) removes these molecules more effectively than standard hemodialysis (HD), it has been suggested that online HDF improves survival and cardiovascular outcome. Thus far, no conclusive data of HDF on target organ damage and cardiovascular morbidity and mortality are available. Therefore, the CONvective TRAnsport STudy (CONTRAST) has been initiated.

Methods

CONTRAST is a Dutch multi-center randomised controlled trial. In this trial, approximately 800 chronic hemodialysis patients will be randomised between online HDF and low-flux HD, and followed for three years. The primary endpoint is all cause mortality. The main secondary outcome variables are fatal and non-fatal cardiovascular events.

Conclusion

The study is designed to provide conclusive evidence whether online HDF leads to a lower mortality and less cardiovascular events as compared to standard HD.     

秀山湾兰多维列末期胞石成种与特型

特型包括形态特型和大小特型。特型是特殊环境的产物。随着温度上升、海水粘度下降,迁入并被隔离于温（盐）跃层内的Ａｎｇｏｃｈｉｔｉｎａｌｏｎｇｉｃｏｌｉｓ产生成种作用。Ｌａｍｂｄａｃｈｉｔｉｎａｂｉｐｅｄａｔａ和Ｌ．ｓｙｎａｐｈａｃａｎｔｈａ减少体积、增加表面积而上浮;Ａｎｇｏｃｈｉｔｉｎａｓｐ．增加体积而下沉：各自开发空生态灶。前者采取了ｒ策略,后者采取Ｋ策略。本文支持胞石是后生动物卵的卵囊的观点,认为：侏儒是按发育程序,但提前孵化的卵的卵囊,巨型是直接孵化（超期孵化）的卵的卵囊。Ａ．ｓｐ．的形态改变通过细胞分裂超期和加速而实现。成种作用产生的新生分子的形态和大小为空生态灶的容量和位置所渠导,具有明显的方向性。     

小苍兰试管球茎诱导及开花研究

小苍兰茎尖在含３．０ｍｇ／ＬＢＡ＋０．２ｍｇ／ＬＮＡＡ的ＭＳ培养基上,可诱导出许多侧芽。侧芽转移至０．５ｍｇ／ＬＩＢＡ＋０．５％活性炭的ＭＳ培养基,在１３＋２℃温度下培养１个月能诱导成小球茎。经电泳鉴定,试管球茎的可溶性蛋白质谱带与常规球茎的谱带完全相同。试管球移栽后约经７个月即可开花,其观赏性状完全稳定,花后成熟的大球达到商品球标准,可直接用于切花生产。     

维持性血液透析患者营养状况及营养不良的影响因素分析

目的:探讨维持性血液透析(MHD)患者营养状况以及营养不良的影响因素,为临床工作提供指导。方法:选择2010年-2014年在我院进行MHD治疗的120例患者作为研究对象,采用改良定量主观整体评估表(MQSGA)并结合相关生化指标测定等手段综合评估透析患者营养状况,分析MHD患者发生营养不良的危险因素。结果:MQSGA评估显示,营养正常组50例(41.67%),轻中度营养不良组61例(50.83%),重度营养不良组9例(7.50%)。不同营养状况组患者间Alb、PA、Cr比较差异有统计学意义(P0.05)。Logistic回归模型显示,Kt/V1.20、年龄≥60岁、透析龄≥3年及hs-CRP≥3 mg/L是MHD患者发生营养不良的危险因素。结论:MHD患者中发生营养不良的比例较大,Kt/V1.20、年龄≥60岁、透析龄≥3年及hs-CRP≥3 mg/L是其危险因素,可作为评价生营养不良的可靠指标。