A radioimmunoassay study and comparison of seasonal variation in plasma triiodothyronine and thyroxine concentrations in normal healthy persons

The serum triiodothyronine (T3) and thyroxine (T4) concentration of healthy persons remains almost constant for at least ten months. Fresh serum and serum frozen for two years were compared. The mean difference in T3 concentration is negligible, only 3 ng/100 ml. The radioimmunoassay has a Between Assay Coefficient of 6.3% and is therefore reliable. Results can be obta     

自体骨髓间充质干细胞移植后心肌缝隙连接蛋白43表达与室性心动过速发生的关系

目的:缝隙连接蛋白43对维持心肌细胞的连接通讯功能、电信号传导和正常的节律性收缩起重要作用,其表达和分布的异常是多种室性心律失常的解剖学基础,建立小型猪急性心肌梗死模型.观察自体骨髓间充质干细胞移植后室性心动过速的发生及心肌缝隙连接蛋白43的表达方法:实验于2006-01/2007-01在河北省人民医院导管室完成。①材料:选取8～12月龄小型猪22头,由河北医科大学实验动物中心提供,体质量20～30 kg,随机数字表法分为细胞移植组12头、模型对照组10头.实验过程中对动物的处置符合动物伦理学际准②实验方法:无菌条件下抽取猪双侧股骨骨髓20 mL,percoll法 贴壁法分离培养骨髓间充质干细胞,待细胞生长达75%融合时用胰酶消化传代。将传至第2代细胞加入终浓度为10μmol/L的5-氮胞苷进行诱导,用胶体金标记12 h后继续培养20 d用于移植:两组小型猪均采用球囊堵闭法建立急性心肌梗死模型.心电图监测示相关至少2个导联ST段抬高大于0.2 mV、术后血肌钙蛋白和肌酸磷酸激酶同工酶升高超过正常的两倍为建模成功标准:细胞移植组于造模成功后经OTW球囊于第一对角支远端1 cm处再次阻断血流,注入经胶体金标记的10×10~7个骨髓间充质干细胞。③实验评估:于细胞移植后2 h及4周行电生理程序刺激.观察室性心动过速的发生情况。末次电生理检查后、采用免疫组化染色法检测心肌缝隙连接蛋白43的表达.计算其积分吸光度值。结果:①模型建立指标检测:与术前比较.造模后所有小型猪血肌钙蛋白含量和肌酸磷酸激酶同工酶活性均增高,峰值浓度分别为(21.3±3.6)μg/L和(178.3×41.4)IU/L,术中心电图ST段平均抬高(10.67±1.43)mm.证明急性心肌梗死模型成功建立。②骨髓间充质干细胞移植后室性心动过速的发生情况:与模型对照组诱发出室性心动过速的动物数量比较,术后2 h细胞移植组无明显变化(X~2=0.201,P=0.650),术后4周细胞移植组明显降低(X~2=4.455.P=0.035)。②骨髓间充质干细胞移植后梗死心肌缝隙连接蛋白43的表达:术后4周移植到梗死心肌的骨髓间充质干细胞与宿主心肌生长为一体,移植部位颜色变黑,苏木精-伊红染色示移植细胞的胞浆呈紫红色。细胞移植组心肌梗死区缝隙连接蛋白43积分吸光度值明显高于模型对照组(t=16,82.P=0.00),细胞移植组中未发生室性心动过速小型猪的梗死心肌缝隙连接蛋白43的表达明显高于发生室性心动过速小型猪(t=5.06,P=0.00)。结论:自体骨髓间充质干细胞移植可促进急性心肌梗死猪心肌缝隙连接蛋白43的表达,其表达程度可能与急性心肌梗死室性心动过速的发生有关。     

Taguchi S/N and TOPSIS Based Optimization of Fused Deposition Modelling and Vapor Finishing Process for Manufacturing of ABS Plastic Parts

Despite several additive manufacturing techniques are commercially available in market, Fused Deposition Modeling (FDM) is increasingly used by researchers and engineers for new product development. FDM is an established process with a plethora of advantages, but the visible surface roughness (SR), being an intrinsic limitation, is major barrier against utilization of fabricated parts for practical applications. In the present study, the chemical finishing method, using vapour of acetone mixed with heated air, is being used. The combined impact of orientation angle, finishing temperature and finishing time has been studied using Taguchi and ANOVA, whereas multi-criteria optimization is performed using the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS). The surface finish was highly responsive to increase in temperature while orientation angle of 0° yielded maximum strength; increase in finishing time led to weight gain of FDM parts. As the temperature increases, the percentage change in surface roughness increases as higher temperature assists the melt down process. On the other hand, anisotropic behaviour plays a major role during tensile testing. The Signal-to-noise (S/N) ratio plots, and ANOVA results indicated that surface finish is directly proportionate to finishing time because a longer exposure results in complete layer reflowing and settlement.     

Effect of recombinant granulocyte colony-stimulating factor on neutrophil kinetics in normal young and elderly humans

Recombinant granulocyte colony-stimulating factor (G-CSF) was administered to healthy young (n = 32) and elderly (n = 19) volunteers (0 microgram/d, 30 microgram/d, or 300 microgram/d) to determine its effect on neutrophil production, blood kinetics, and tissue migration. Measurements included blood counts (daily), marrow neutrophil pool sizes and neutrophil tissue migration (baseline and day 5), blood kinetics (day 6), and marrow transit time while on drug (days 6 to 14). G-CSF markedly expanded the marrow neutrophil mitotic pool and shortened the transit time of the postmitotic pool (control, mean = 6.4 days; 300 microgram/d, mean = 2.9 d). G-CSF increased neutrophil production without significantly altering blood neutrophil half-life or margination. Compared to control, neutrophil accumulation in skin chambers decreased by about 50% in the 300 microgram/d group in both young and elderly subjects. G-CSF induced neutrophilia by stimulating proliferation of marrow neutrophil precursors and accelerating neutrophil entry into the blood. Decreased neutrophil inflammatory responses measured with the skin chamber technique may be because of the relative immaturity of the circulating cells or to alterations in neutrophil phenotype induced by G-CSF.     

Correlation of the biologic effects and binding of cytochalasins to human polymorphonuclear leukocytes

Treatment of human PMNs with cytochalasins (CE, CD, CB, and H2CB) results in alteration of cell morphology and inhibition of cell motility. Morphological changes are similar to those reported for nonamoeboid fibroblasts--rounding, zeiosis, and arborization. Mean cell velocity of PMNs, as measured by quantitative analysis of time-lapse videotape recordings, was reduced to 0.1 micron/min (control, 7.3 +/- 4.2 micron/min). Phagocytosis by PMNs, as measured by phagocytosis of latex beads, was inhibited by 75%. The relative potency of the cytochalasins for inducing morphological change or for inhibiting locomotion and phagocytosis is similar to their relative potencies for affecting non-amoeboid cells: CE greater than CD greater than CB greater than or equal to H2CB. Quantitative binding of 3H-CB to purified PMNs under equilibrium conditions reveal two types of specific CB binding sites: high-affinity sites (KD approximately 3 x 10(-7) M, 3 x 10(6) sites/cell) and low affinity sites (KD approximately 2 x 10(-6) M). The relative affinities of the cytochalasins for the high-affinity and low-affinity CB binding sites parallel their relative potencies for inducing biologic effects (i.e. CE greater than CD greater than CB greater than or equal to H2CB).