脱细胞牛心包构建引导骨再生膜的初步研究

目的制备具有良好生物相容性和适宜降解吸收时间的引导骨组织再生（guided bone regeneration，GBR）膜材料。方法采用0．25％Trypsin＋0．5％Triton X-100酶联脱细胞法对新鲜牛心包进行脱细胞处理，将脱细胞牛心包（A组）、甘油保存脱细胞牛心包（B组）、碳化二亚胺[1-ethyl-3-（3-dimethylamino propyl）carbodiimide hydrochloride，EDAC]交联脱细胞牛心包（C组）、甘油保存EDAC交联脱细胞牛心包（D组）4种膜材料分别植入38只SD大鼠背部皮下，不植人材料为E组。于2、4、8和16周分别处死大鼠7、12、12和7只，观察周围组织反应及材料的降解吸收情况。结果4种材料植入动物体内均有不同程度的炎性反应和纤维囊膜形成。术后4周，A组和C组的炎性反应轻微，纤维包膜变薄。A组膜材料吸收替代时间为8周左右，C组吸收替代时间为16周左右；16周时B组和D组材料仍有纤维包膜。结论EDAC交联脱细胞牛心包具有良好的生物相容性和理想的降解性能，在动物体内能顺利被自体组织替代。     

Link protein shows species variation in its susceptibility to proteolysis.

Human cartilage link protein exists as three native components, while equine, bovine, and porcine cartilage link protein exist as two and Swarm rat chondrosarcoma link protein exists as only one component. These nonhuman link protein components represent intact protein structures, and there is little evidence for proteolytically modified forms in nonhuman tissues. In human cartilage, the proteolytic production of modified link proteins increases with age, whereas high amounts of such products were not seen in the nonhuman tissues. However, the small amounts of link protein fragments that were observed in the nonhuman cartilages were of a similar size to their human counterparts. On digestion of human proteoglycan aggregate with stromelysin, rapid modification of the link protein components occurred, whereas the aggregates from nonhuman cartilages showed incomplete cleavage of their link protein components. The relative resistance of nonhuman link protein to stromelysin may in part be due to a unique amino acid substitution present near the enzymic cleave site.     

Hen liver and plasma can metabolize hexyl-DCP phosphoramidate at a rate comparable to that of rat

The in vitro and in vivo biochemical properties of O-hexyl, O-dichlorophenyl phosphoramidate (hexyl-DCP) as inhibitor of acetylcholinesterase (AChE) and neuropathy target esterase (NTE) were studied, as well as their neurotoxic effects. The differences found were suggested to be due to biotransformation effects. In this work, the in vitro time-dependent degradation of hexyl-DCP by plasma, liver and brain homogenates of rat and hen at 37°C at pH 7.4 are studied using 100 nM initial concentration. The loss of inhibitory potency against AChE was used as sensor of the biodegradation rate. An approximate estimation of the residual compound was made by comparison with an inhibition calibration curve. The rate of enzymatic degradation was corrected for the spontaneous hydrolysis. Rat tissues showed some higher activities (24, 17, 1 mU/g for plasma, liver, and brain, respectively) than hen (17, 6, 1 mU/g), with activities being highest for plasma and lowest for brain. Hexyl-DCP is a chiral compound. The loss of anti-AChE power could be due to degradation of only one of the two stereoisomers.     

Effect of iron on the surface, degradation and ion release properties of phosphate-based glass fibres

Phosphate-based glass fibres (PGF) have the unique characteristic of being completely soluble in an aqueous environment, releasing bioactive and biocompatible ions. They have been proposed as tissue engineering scaffolds for craniofacial skeletal muscle regeneration, where myoblasts are seeded directly onto the fibres. Studies have shown that these cells have a preference in their initial attachment to fibres of certain composition and size, which in turn control the rate of degradation. This study investigated the relationship between the surface properties, degradation properties and ion release (cationic and anionic species) by altering the chemical composition of the PGF. Iron oxide (Fe2O3) was incorporated into glasses containing P2O5 (50 mol%), CaO (30 mol%) and Na2O (20 mol%). Six glass compositions with Fe2O3 ranging from 0 to 5 mol% by replacing the equivalent Na2O mol% were investigated. Contact angle measurements showed that polar interactions occurring on the glass surfaces diminished with increasing Fe2O3 content. This behaviour was reflected in the estimated surface energies of the glasses, where the overall surface energy decreased with increasing Fe2O3 content due to the decrease in polar or acid/base component. The incorporation of up to 5 mol% Fe2O3 into PGF resulted in a significant reduction in the degradation rate (by two orders of magnitude), which can be related to the formation of more hydration resistant P-O-Fe bonds. However, the degradation rate increased with decreasing fibre diameter (comparing average diameters of 31.6 +/- 6.5 microm versus 13.1 +/- 1.3 microm) for a given mass of fibre, and this is related to the surface area to volume ratio. Taken together the results suggest that fibres with the larger diameters and containing 3-5 mol% Fe2O3 could initially be a more durable scaffold than ones with 1 or 2 mol% Fe2O3 for initial cell attachment.     

十二烷基硫酸钠在天然水体中的降解作用

本文研究了十二烷基硫酸钠在天然水体中的降解作用,结果表明十二烷基硫酸钠在天然水体中的降解主要依赖于微生物的降解。微生物最适降解条件为ｐＨ６．５～９．４和３６℃左右。降解作用随温度升高（４～３６．５℃）和微生物浓度增大而加快,用十二烷基硫酸钠预先驯化微...     

Effect of carbon disulphide intoxication on fecal excretion of end products of cholesterol metabolism

Summary The aim of this study was to compare the time course of ¹⁴C-steroid excretion following administration of ¹⁴C-cholesterol in normal and CS₂intoxicated rats. The excretion of steroid with the feces was evaluated in the normal and CS₂ intoxicated rats at the end of 7 month exposure to CS₂. The results of the experiment indicated that in rats exposed to CS₂ excretion of ¹⁴C-steroid is lower. It was due to a reduced excretion of ¹⁴C-bile acid fraction while at the same time the share of sterol + rose. On the basis of our former results which excluded the influence of CS₂ on absorption of cholesterol and indicated its effect on cholesterol synthesis it was revealed in this experiment that intoxication with CS₂ also inhibits cholesterol degradation. Disturbances of both processes can be essential for accumulation of cholesterol in blood of animals intoxicated with CS₂.This investigation has been carried out under the Polish-American agreement No. 05-008-2 with the Occupational Health Program, U.S. Public Health Service     

海带硫酸多糖的降解、分离纯化及理化性质分析

文章采用自由基方法降解海带硫酸多糖，然后通过琼脂糖凝胶电泳、凝胶色谱等方法进行分离纯化；分别利用硫酸酚法和明胶比浊法，测定糖的含量和硫酸根的含量；MN-纤维素膜层析和气相色谱测定单糖组成；利用超滤和凝胶过滤测定降解多糖的分子质量等。海带硫酸多糖可以被自由基有效地降解，降解之后海带硫酸多糖的多糖含量、硫酸根含量及单糖组成基本没有变化，分子质量可被降解到10000-15000左右。     

剖宫产术中放置吉娜IUD后产褥出血量及恶露持续时间的观察

目的:观察剖宫产术中放置吉娜固定式宫内节育器(GyneFix PP IUD)对产时、产后出血、恶露持续时间及子宫复旧的影响。方法:对200例剖宫产放置吉娜IUD和204例剖宫产未放IUD妇女产时、产后出血量,产后恶露持续时间进行比较,并B超复查产后42天、90天时子宫复旧情况及吉娜IUD的状况。结果:两组产后出血量、恶露持续时间无显著差异,子宫复旧正常。在产后42天复查时吉娜脱落率为4％。86％的妇女可在宫颈见到吉娜尾丝。结论:剖宫产术即时放置吉娜IUD是安全的,未增加产后出血量及恶露持续时间,不影响子宫复旧,为产后即时避孕提供了新的选择。     

HPLC检测长春西汀葡萄糖注射液中降解产物5-羟甲基糠醛

目的建立测定长春西汀葡萄糖注射液中降解产物5-羟甲基糠醛(5-HMF)含量的方法。方法采用HPLC法,色谱柱为KromasilODS-1C18(4.6mm×250mm);流动相为0.2%磷酸-甲醇(75∶25);流速1ml·min-1;检测波长284nm。以外标法测定5-HMF的含量。结果在1.0~20.0μg·ml-1范围内,对照品峰面积与浓度的线性关系良好(r=0.9999),加样平均回收率为99.5%,RSD=1.0%(n=5),最低检测浓度为7·7ng·ml-1。结论所用方法简便、准确、重复性好,可用于长春西汀葡萄糖注射液中降解产物5-HMF的检测。     

Role of Matrix Metalloproteinases in Skin Ageing

Matrix metalloproteinases are a family of ubiquitous endopeptidases playing a role in many different physiological and pathological processes in the skin. They are also involved in cutaneous ageing. This review summarizes the features and regulation of these enzymes and presents an overview of the molecular mechanisms of both intrinsic and extrinsic skin ageing presents. The role of matrix metalloproteinases in skin ageing is discussed in detail.