聚多巴胺改性聚合物在神经修复中的研究进展 *

多巴胺在碱性条件下会发生自聚合生成聚多巴胺。由于聚多巴胺具有超强黏附性能,在过去几年中其被大量应用于修饰各类生物材料。神经修复中使用的材料多为聚合物,但单独使用聚合物修复神经的效果不佳。聚多巴胺改性聚合物的亲水性和生物相容性均优于单一聚合物。除此以外,聚合物上的聚多巴胺涂层还可用于进一步修饰促进神经修复的分子。综述了聚多巴胺的合成机理、性能以及聚多巴胺改性各类聚合物在神经修复中的研究进展,并展望了该类材料的发展前景。     

难溶于二甲亚砜多糖的甲基化方法研究

本文对难溶于二甲亚砜(DMSO)但易溶于水的多糖——羊栖菜褐藻糖胶的甲基化方法进行了研究。10mg多糖用0．1mL水溶解后,加和3mL DMSO,使多糖转溶于DMSO,然后加人2mL 3A分子筛脱除水分。将DNSO溶液过滤后,滤液中加入50mg NaOH粉末,室温下反应10min。加入0．5mL碘甲烷,室温下反应60min。加1mL水终止反应,加1mol／L HAc中和、透析、冻干。该法简便易行,所得产物的甲基化程度比较高。     

用斑点酶联免疫吸附试验检测轮状病毒抗原

我们用国产试剂和材料建立了一种以硝酸纤维素膜(NCM)作为固相载体的斑点酶联免疫吸附试验(Dot-ELISA),用于检测粪标本中的轮状病毒. 首先用铁笔将NCM划成5×5mm的小方格,然后将免抗人轮状病毒IgG打点至方格中心,室温凉干后,置封闭液中室温作用1小时,取出用PBST洗涤3～5次,每次5分钟,然后将膜直接浸入待检粪样、阳性抗原对照和阴性抗原对照中.置37℃ 30～60分钟,洗涤。随后将上述诊断膜浸入酶标兔抗人轮状病毒IgG中,室温45～60分钟,洗涤。用底物DAB显色数分钟,至阳性对照样本出现明显褐色斑点时,用自来水终止反应。根据斑点颜色深浅,肉眼即可判断阳性或阴性结果。     

锁阳种子生活力测定及前处理的方法

以野生充分成熟的锁阳净种子为材料,研究了附属物清除、硬实破除及生活力测定的方法。结果表明,清除锁阳种子附属物最有效的方法是开水烫种,冷至室温浸种24h后用尼龙纱网搓揉和1％的NaOH溶液处理。破除硬实,去除种皮最适宜的方法是1．0mol·L-1的NaOH处理5h、1．5mol·L-1的NaOH处理4～5h、2．0mol·L-1的NaOH处理3～5h。测定锁阳种子生活力的最佳方法是20℃光照条件下离体培养15d。     

苧麻组织培养再生植株研究

植物名称:苎麻(Bochmeria nivea L.) 品种:广西黑皮蔸。材料类别:茎和叶。培养条件:基本培养基MS,另有附加成份:2.4-D或NAA0.5毫克/升,6-BA(6苄基嘌呤)或玉米素(ZT)2～5毫克/升。培养基内均加水解酪蛋白500毫克/升,蔗糖3％,琼脂0.8％,pH5.8～6.0,常规消毒灭菌接种。材料置于室温(24～34℃)和     

木材制片的一种新方法

本文介绍一种木材制片的方法,这种方法可靠易行,其步骤如下: 1.取材:根据观察目的选取试验材料,要照顾三个切面的位置.材料大小一般切成1.5×1.5×1.5立方厘米为宜. 2.软化:将材料置于相当于材料5倍体积的10%乙二胺水溶液中浸泡,放在60℃温箱内;浸泡时间视材料软硬程度而定,一般3～5天即可.特别硬的材料可延长至10天以上,其间应更换一次溶液.对特别软的或腐朽的材料可以用4%乙二胺水溶液在室温下     

聚乙烯醇的生物降解

聚乙烯醇(PVA)是较少的可溶于水并被生物降解的乙烯聚合物之一。研究表明,在受PVA污染的自然环境中存在着能降解PVA的微生物,并从中提取出了PVA降解酶。介绍了国内外研究聚乙烯醇生物降解的情况。分别讨论了聚乙烯醇被单一菌种、共生细菌和真菌降解过程中的生物化学和生理学特性,以及结构因素对聚乙烯醇生物降解的影响。这些研究促进了可有效生物降解的PVA类材料产品项目的发展。     

沙漠玫瑰的组织培养

是植物名称沙漠玫瑰（A山如规（Desl’IT。2材料类别茎尖、带眼芽茎段。3培养条件基本培养基为MS。芽增殖培养基为MS＋BAI．0～20ms／L（单位下同）＋KTI．0～2．0;诱导生根培养基为1／ZMS＋IBAI．0～1．5。各种培养基均用0．65％卡拉胶固化,PH5．8,培养室光照度2000IX,每天辅助光照10～12h,室温25～30C。4生长与分化情况4．工外植体的消毒和接种茎尖、茎段用0．l％HgCI。溶液消毒3～4min,无菌水冲洗2次,再用0．正％HgCI。溶液消毒4～5min,最后用无菌水冲洗3～4次,在无菌条件下将茎段切成0．4～0．5cm长的切段接种到…     

吊竹梅茎段培养成完整植株

植物名称:吊竹梅(Zebrina pendula)。材料类别:带节茎段。培养条件:茎去叶后用饱和漂白精片浸出液消毒4～6分钟,后用无菌水冲洗4～5次。切成长1.5～2.5cm的带节茎段。随后接入BA2mg/l与NAA0.2mg/l的 MS固体培养基上。诱导发根的培养基为:1/2MS+0.2mg/l NAA。在室温25±     

蚕丝在生物医学应用上的研究进展

蚕丝作为一种天然的蛋白质聚合物,在生物医学领域越来越受到研究者的广泛关注。它具有独特的优良性能,不仅可以单独用作生物医学材料,也可以和其他材料一起混合成新材料。简要阐述了近年来蚕丝应用在组织工程、活性分子配送系统及肿瘤等疾病治疗方面的研究进展。     

A homozygous female hemophilia A

BACKGROUND:

Hemophilia A (HA), being an X-linked recessive disorder, females are rarely affected, although they can be carriers.

AIMS:

To study the mutation in F8 gene in an extended family with a homozygous female HA.

MATERIALS AND METHODS:

All the seven affected members (six males and one female) were initially screened by Conformation Sensitive Gel Electrophoresis (CSGE) and direct DNA sequencing.

RESULTS:

A homozygous missense mutation c.1315G>A (p.Gly420Ser) was identified in exon 9 of F8 gene in homozygous state in the affected female born of 1° consanguinous marriage and in all the affected male members of the family. Her factor VIII levels was found to be 5.5%, vWF:Ag 120%.

CONCLUSION:

In India, as consanguineous marriages are very common in certain communities (up to 30%), the likelihood of encountering female hemophilia is higher, although this is the first case of HA out of 1600 hemophilia families registered in our Comprehensive Haemophilia Care Center. Genetic diagnosis in such cases is not necessary as all the male children will be affected and daughters obligatory carriers.     

A glucoside of urospermal A

The aerial parts of Urospermum picroides afforded, in addition to urospermal A a p-hydroxylphenyl acetate of a glucoside of urospermal A.     

Aminopeptidase A is angiotensinase A

Summary Quantitative histochemical measurements of aminopeptidase A (APA; E.C.3.4.11.7) were done kinetically in the kidney glomeruli of rat and mouse with an instrumental setup consisting of a microdensitometer and a computer-supported morphometric system. The histochemical demonstration of APA was carried out using the simultaneous azo coupling technique (purest-grade Fast Blue B as coupling agent and -l-glutamic acid-4-methoxy-2-naphthylamide as substrate). The methodological studies show that APA activity is calcium-ion-dependent and increases linearly with the thickness of the tissue section (3–12 m) and that the time-course of APA activity as determined by linear regression is linear only for the first 1 to 2 min of the reaction. — Kinetic measurements indicate a 40% decrease in APA activities when -l-glutamic acid-4-methoxy-2-naphthylamide (-l-Glu-MNA) is replaced by -l-aspartic acid-4-methoxy-2-naphthylamide. When -l-Glu-MNA is replaced with l-alanine-4-methoxy-2-naphthylamide, which is a substrate of aminopeptidase M (APM) only very low reaction rates are measurable (about 1.4% of those with -l-Glu-MNA). 100 and 130 mM NaCl in the incubation medium increase APA activities by approximately 16%–17%. — To clarify the functional importance of APA in the kidney, their activities were measured under the influence of angiotensins. The glomerulus was selected as the measuring site, for besides APA it contains no APM or other peptidases that could degrade angiotensins (the glomerular dipeptidyl peptidase IV is not inhibited by angiotensin II). Using the Lineweaver-Burk plot, we determined a K _m of 0.16 mM for the APA in rat glomeruli and 0.14 mM in mouse glomeruli. The V _max in mouse glomeruli is 1.6 times higher than in rat glomeruli. Ang iotensin I, II and III competitively inhibit APA in the rat and mouse glomeruli. — With quantitative histochemical techniques it was possible to show that APA is equivalent to angiotensinase A (splitting off the N-terminal aspartic acid from angiotensin I and II).Supported by the Deutsche Forschungsgemeinschaft (SFB 105)     

Quadruplexes of human telomere DNA analogs designed to contain G:A:G:A,G:G:A:A,and A:A:A:A tetrads

Replacement of two to four guanines by adenines in the human telomere DNA repeat dG₃(TTAG₃)₃ did not hinder the formation of quadruplexes if the substitutions took place in the terminal tetrad bridged by the diagonal loop of the intramolecular antiparallel three‐tetrad scaffold, as proved by CD and PAGE in both Na⁺ and K⁺ solutions. Thermodynamic data showed that, in Na⁺ solution, the dG₃(TTAG₃)₃ quadruplex was destabilized, the least by the two G:A:G:A tetrads, the most by the G:G:A:A tetrad in which the adenosines replaced syn‐guanosines. In physiological K⁺ solution, the highest destabilization was caused by the 4A tetrad. In K⁺, only the unmodified dG₃(TTAG₃)₃ quadruplex rearranged into a K⁺‐dependent quadruplex form, none of the multiple adenine‐modified structures did so. This may imply biological consequences for nonrepaired A‐for‐G mutations. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 880–886, 2010.