微型种植体支抗愈合期稳定性的比较

目的比较不同愈合时间种植体支抗的稳定性。方法10只新西兰大白兔应用种植体60枚,均分为种植即刻组、种植后1周组、2周组、4周组、8周组进行拉出实验和转矩实验。采用单因素方差分析组间差异,相关性分析愈合时间、最大剪切力、最大力矩两两之间的相关性。结果4周与8周组最大剪切力分别为(179·68±24·65)N、(212·06±42·51)N;4周与8周组的最大力矩分别为(0·47±0·13)N·m、(0·61±0·16)N·m,与其他组相比差异均有统计学意义(P<0·05)。愈合时间、最大剪切力、最大力矩两两之间均呈正相关。结论4周是种植体愈合期生物稳定性的一个关键时间点。8周内种植体的生物力学性能与愈合时间呈正相关。     

羟基红花黄色素A的Caco-2细胞摄取转运研究

 目的研究羟基红花黄色素A(HSYA)的胃肠吸收转运机制。方法采用Caco-2细胞模型考察孵育时间、介质pH、药物浓度及抑制剂(环孢菌素A和叠氮钠)对羟基红花黄色素A摄取转运的影响,并分析HSYA灌胃给药后在大鼠尿及粪中的累积排泄。结果HSYA的摄取符合被动扩散过程,pH7.8环境下药物的细胞摄取量[(1.05±0.045)mg·g^-1]低于pH5.4[(1.24±0.09)mg·g^-1](P<0.05),其在Caco-2单细胞层的表观透过系数(Papp)为(2.16±1.21)×10^-8cm·s^-1,加入环孢菌素A和叠氮钠后其Papp显著提高(P<0.05),分别为(47.92±17.8)×10^-8和(12.53±4.55)×10^-8cm·s^-1。HSYA大鼠灌胃给药(5.6mg·kg^-1)后31h,其尿和粪中的累积排泄量分别为给药剂量的0.74%和28.57%。结论HSYA的吸收基本符合被动扩散过程并有P-gp的参与,其黏膜透过性较差,碱性环境相对不利于药物的吸收。HSYA口服后的胃肠吸收较差,大量的药物被排出体外或在胃肠道内被代谢转化。     

替硝唑葡萄糖注射液的稳定性研究

采用反相ＨＰＬＣ法测定替硝唑葡萄糖注射液中替硝唑的含量，用加温加速实验研究该制剂的热稳定动力学。结果表明，替硝唑的热降解反应为一级动力学过程，在５０、６５、８０、９５℃时的降解速度常数分别为５．５８×１０－４、２．６６×１０－３、８．１０×１０－３、２．８２×１０－２ｄ－１，为８．３年，半衰期为３９．５年。     

补碘对7～12岁轻度碘缺乏病儿童脑功能及生长、发育的影响

通过半年对３５名７～１２岁轻度碘缺乏病儿童进行补碘，并与同龄、同地的正常儿童和缺碘未补碘儿童进行比较，以观察补碘对儿童脑功能及生长发育的影响。结果发现：①补碘可使儿童碘营养状况恢复正常，尿碘值由（８３．２±３．５）μｇ／Ｌ上升到（１６２．２±１．６）μｇ／Ｌ，血清Ｔ４、ＦＴ４Ｉ和ｒＴ３：也与正常儿童一致而与未补碘儿童有显著性差异（Ｐ＜０．０５）．②轻度碘缺乏病儿童智商低于正常儿童（Ｐ＜０．０１），补碘在一定程度上改善其智商水平。③轻度碘缺乏病及补碘未能明显影响儿童的生长发育，可能与儿童总营养水平较差有关。     

Atrial Synchronous Ventricular Pacing with a Single Lead: Reliability of Atrial Sensing During Physical Activities, and Long-term Stability of Atrial Sensing

A VDD pacing system with bipolar single-pass leads, were implanted in 36 consecutive patients (average age 72 ± 2years) with high degree atrioventricular block and normal sinus node function. At implant the atrial signal amplitude was 2.6 ± 0.2mV measured by a pacing system analyser (PSA), 1.8 ± 0.1mV measured peak-to-peak from the telemetered calibrated electrogram, and 1.3 ± 0.1mV measured from the sensing threshold. At one month follow-up the peak-to-peak amplitudes (mV) of the telemetered atrial electrograms were not significantly different measured continuously during resting supine with quiet breathing (1.4 ± 0.1), sitting (1.6 ± 0.2). standing (1.5 ± 0.1), arm swinging (1.4 ± 0.2), hyperventilation (1.3 ± 0.1), Vaisalva manoeuvre (1.4 ± 0.1), and treadmill exercise (1.9 ± 0.6). The telemetered atrial electrogram amplitude and the atrial sensing threshold varied between 1.2 ± 0.09mV and 1.8 ± 0.1mV, and between 0.95 ± 0.07mV and 1.3 ± 0.01mV, respectively at 0.5, 1, 3, 6 and 12 months follow-up, but the changes were statistically nonsignificant. The Event Summary showed sensing of 98% to 99% of the atrial events at the different follow-up periods.     

弱智儿童与正常儿童智力结构的比较研究

以中国－韦氏儿童智力量表和修订幼儿Ｈ．Ｒ神经心理测验中的范畴测验作为儿童智力和思维能力的指标，对４７名８－１１岁弱智儿童和５０名普通小学儿童进行了测试，发现弱智儿童ＩＱ在４６－６９之间，属智力迟滞，与教育的筛选结果相同。且危险因素明显多于正常儿童。正常儿童ＩＱ在１１０－１３３之间，属高于平常智力，两组间有显著性差异。两组儿童智力结构图走势相似，提示智力测验对个体的指导意义更大。弱智儿童与正常儿童的范畴测验得分有极显著的差异，且与ＩＱ呈显著负相关，提示范畴测验鉴别力良好，可单独作为儿童思维能力的检测指标。     

丝裂霉素C化学稳定性的研究

在广泛ＰＨ范围内对丝裂霉素Ｃ的化学稳定性进行了研究，测定不同温度下不同ｐＨ时的速率常数，得到不同ｐＨ时的分解活化能及不同温度下的稳定ｐＨ值。活化能数据在ｐＨ５．５及７．８时出现极大值，而不同温度下的两上最稳定（ｐＨ）ｍ恰恰位于两个ｐＨ范围内。     

Effect of Glass Transition Temperature on the Stability of Lyophilized Formulations Containing a Chimeric Therapeutic Monoclonal Antibody

Purpose. The purpose of this study is to highlight the importance of knowing the glass transition temperature, T_g, of a lyophilized amorphous solid composed primarily of a sugar and a protein in the interpretation of accelerated stability data. Methods. Glass transition temperatures were measured using DSC and dielectric relaxation spectroscopy. Aggregation of protein in the solid state was monitored using size-exclusion chromatography. Results. Sucrose formulation (T_g ~ 59°C) when stored at 60°C was found to undergo significant aggregation, while the trehalose formulation (T_g ~ 80°C) was stable at 60°C. The instability observed with sucrose formulation at 60°C can be attributed to its T_g (~59°C) being close to the testing temperature. Increase in the protein/sugar ratio was found to increase the T_gs of the formulations containing sucrose or trehalose, but to different degrees. Conclusions. Since the formulations exist in glassy state during their shelf-life, accelerated stability data generated in the glassy state (40°C) is perhaps a better predictor of the relative stability of formulations than the data generated at a higher temperature (60°C) where one formulation is in the glassy state while the other is near or above its T_g.     

Stability of subtilisins and related proteinases (subtilases)

The stability towards thermal and chemical (guanidine hydrochloride, GnHCl) denaturation of six inhibited subtilases (mesentericopeptidase, subtilisins BPN′, Carlsberg and DY, proteinase K and thermitase) has been investigated by kinetic and equilibrium studies. The unfolding processes were monitored by circular dichroic and fluorescence spectroscopy. Experiments in the absence and presence of extraneous calcium in the concentration range 2×10^?3-10^?1 M were performed. The presence of calcium in the weak calcium binding site changes the denaturation drastically. The heat- (or GnHCl-) induced unfolding curves obtained using CD spectroscopy show two independent transitions which seem not to have been resolved before. The presence of Ca²⁺ in the second (third in the case of thermitase) binding site increases the T_m, values by 11-21 °C and the δG_D(H₂O) values obtained from denaturation experiments in GnHCl by 6.7-7.2 kcal/mol when an extraneous Ca²⁺ concentration of 2 × 10^?2 M was used. One interpretation is that the initial step of denaturation in the presence of added calcium is the formation of a partially unfolded intermediate form, retaining a highly ordered structure with 60-85% of the a-helix structure of the native enzyme. This intermediate then unfolds at a temperature considerably higher than that of the same proteinases in the absence of added Ca²⁺. The free energy of stabilization of the intermediates is increased by 1.8-2.8 times in comparison with that for the unfolding reactions of the subtilases with empty Ca2/Ca3 binding sites. A second interpretation is that the two steps in the unfolding curves correspond to enzyme without and with calcium in the weak binding site. Fluorescence experiments confirm the mechanism involving the formation of intermediate states. The results are discussed in relation to the X-ray models of the six subtilases.     

学龄儿童单纯性肥胖对智商影响的meta分析

目的 应用meta分析正确评价学龄儿童单纯性肥胖对智商的影响。方法 对检索到的符合标准的11篇相关文献进行meta分析，选择随机效应模型进行统计处理。结果 单纯性肥胖组与对照组儿童智商比较，平均较应尺度为-0．3385，平均效应尺度的95％可信区间为-0．8036～0．1266。结论 单纯性肥胖对智商影响的meta分析结果无统计学意义。