Stabilization of an inserted tricalcium phosphate spacer enhances the healing of a segmental tibial defect in sheep

The effect of inserting a tricalcium phosphate (TCP) spacer stabilized by a rigid or non-rigid fixation technique on the healing of segmental tibial defects of critical size was established. The osteotomized tibiae, 11 with and 8 without TCP spacers, were fixed by an external circular device in 11 mature sheep and by plates in 8 mature sheep, respectively. Healing was evaluated roentgenographically 16 weeks after the operation. Compared with the defects without TCP spacers, enhanced stability and healing were observed in the defects with TCP spacers under an identical external fixation. Furthermore, a significantly higher incidence of healing was obtained with plate fixation than with external device fixation in the TCP-implanted defects (P < 0.04). An abundant bridging callus was roentgenograpically demonstrated in most of the healed defects, but none in the unhealed defects. The TCP spacer with its mechanical integrity enhances the stability of external fixation, and the stable immobilization provided by rigid fixation is essential for osteoconduction of an inserted TCP spacer in the healing of segmental diaphyseal defects in sheep.     

Purification and chemical modification of porcine bone morphogenetic protein

Implantation of porcine bone morphogenetic protein (pBMP) in the muscle induces differentiation of mesenchymal-type cells and results in endochondral bone formation. pBMP was isolated from porcine demineralized bone matrix and purified by hydroxyapatite chromatography, Sephadex G75 gel filtration, preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), preparative isoelectric focusing (IEF), and chromatofocusing fast protein liquid chromatography (FPLC). Porcine BMP has an MW of 26 K and a range of pI from 4.65 to 4.73 determined by SDS-PAGE and IEF, respectively. Reconstitution with the citrate buffer supernatant fraction enables as little as 50 micrograms of the soluble pBMP fractions to induce osteogenesis in an in vivo assay. Chemical modification studies indicate that the osteoinductive potential of the pBMP molecule depends on tyrosine, carboxyl groups, and disulfide bonds and can be increased by modification of sulfhydryl groups. Modification of arginine and tryptophan has no effect on bioactivity. By pepsin-limited proteolysis, fragments of pBMP with an MW of 6-14 K show definite, although reduced, BMP activity.     

对居民使用液化气健康效应的初步探讨

对液化气燃烧后室内空气污染进行了流行病学调查，结果显示，液化气燃烧可造成ＳＯ＿２、ＮＯ＿２、空气总悬浮颗粒物和总烃类的室内空气污染。小鼠接触三个月出现Ｔ淋巴细胞计数降低、睡眠时间延长、骨髓嗜多染红细胞微核率增加、肺组织匀浆Ａｍｅｓ试验阳性率增高、雄性小鼠精子畸形率增加，并有明显的剂量－反应关系。对接触５年以上的人群调查发现，呼吸道、鼻和眼的自觉症状明显增加，咽炎、鼻炎、结膜炎患病率增高。人群尿液浓缩物Ａｍｅｓ试验和外周血红细胞微核率检出阳性结果，可能与液化气燃烧废气中含有致突变污染物有关。     

Spectral slope of vowels produced by tracheoesophageal speakers

Spectra of vowels were analyzed to determine whether differences exist between the spectral slope of vowels produced by tracheoesophageal (TE) speakers and normal speakers and, if so, to quantify such differences. The linear predictive autocorrelation method was used to calculate smoothed spectra and the spectra were normalized with respect to a low frequency component. Comparisons between normalized spectral energy within a selected high frequency range revealed that energy within this frequency range for vowels produced by TE speakers was significantly higher than that produced by normal speakers. A least-square distance matching procedure was used to quantify speaker group differences in the spectral slope of vowels. Average spectra of vowels produced by the normal speakers could be matched to average spectra of vowels produced by the TE speakers by decreasing the spectral slope of their vowels by 2-3 dB/octave.     

Probes for the cocaine receptor. Potentially irreversible ligands for the dopamine transporter.

Several potentially irreversible ligands (i.e., wash-resistant binding inhibitors) for the cocaine receptor site on the dopamine transporter, derived from (-)-cocaine or 3 beta-phenyltropan-2 beta-carboxylic acid methyl ester (WIN 35,065-2), were prepared and shown to produce wash-resistant inhibition of [3H]-3 beta-(p-fluorophenyl)tropan-2 beta-carboxylic acid methyl ester ([3H]WIN 35,428) binding. All the compounds prepared had the same absolute configuration as cocaine; they include analogues possessing chemically reactive groups such as the isothiocyanato and bromoacetamido as well as photoactive azido groups. The potentially irreversible ligands, as well as all the intermediates prepared in this study, were evaluated for their ability to inhibit the binding of [3H]WIN 35,428 in coincubation experiments. Of the potentially irreversible ligands, 3 beta-(p-chlorophenyl)tropan-2 beta-carboxylic acid 2-[p-(bromoacetamido)phenyl]ethyl ester (6c) had the highest apparent potency. The potentially irreversible ligands were also preincubated, and inhibition of [3H]WIN 35,428 binding was determined both before and after washing the ligand-exposed tissues. The most effective ligands in this regard were 3 beta-(3-iodo-4-azidophenyl)tropan-2 beta-carboxylic acid methyl ester (5) and 3 beta-(p-chlorophenyl)tropan-2 beta-carboxylic acid 2-(3-iodo-4-azidophenyl)ethyl ester (6d). The structure-activity relationships of these data are discussed.     

烧伤大鼠血清对血管内皮细胞通透性的影响

加深入阐明严重烧伤早期全身血管通透性增加继而引直民早期损害的发生机制，本实验应用培养于微孔滤膜上的小牛瞌 及皮细胞单层所构成的选择性通透屏障模型，观察了３０％Ⅲ度烧伤大鼠血清对其影响，结果发现，烧伤早期烧伤血清刺激后ＥＣ单层对Ｈａｎｋｓ液或白蛋白液滤过流量、滤过系数均明显增加。     

定坤丹的显微鉴定研究

对定坤丹(蜜丸)进行了显微鉴定研究,将29种组成药物全部检出,对各组成药物的显微鉴别特征作了简明描述,并附显微特征图。     

纤维组织粘合剂的实验研究

本文应用“冷沉淀”法制备纤维组织粘合剂。对纤维组织粘合剂中主要成份和含量进行了测定,并测定了主要理化性质,建立了动物实验模型,观察了实验兔对纤维粘合剂的反应。     

二甲基甲酰胺与乙醇联合毒性初探

经口分别给予Wistar大鼠蒸馏水、DMF 400mg/kg、乙醇1000mg/kg及DMF400mg/kg 乙醇1000mg/kg,染毒21天。结果表明DMF组及联合染毒组大鼠血清ALT明显增高,SLDH在后者也明显升高,且两组肝组织ATP酶及SDH活性明显降低。各染毒组尿LDH活性显著上升,DMF组及联合染毒r-GT活性显著降低,此两组肾脏组织AKP、ATP、SDH活性也明显降低。上述变化联合染毒组较单独作用组明显,因此认为DMF对肝肾具有损伤作用,乙醇可加重DMF的损伤作用。     

驻广州部队营区大气微生物含量的测定

用平板沉降法测定驻广州部队营区春季大气微生物含量。结果表明,营区大气微生物含量较高(10 311CFU/m~3)。驻市区部队营区大气微生物含量高于近郊营区,建议加强环境卫生监督、监测,控制环境污染。