生物可降解肋骨骨折内固定材料-蚕丝纤维增强纯聚己内酯的体内降解实验研究

目的对纯聚己内酯（PCL）和蚕丝纤维增强PCL多孔复合材料进行体内降解实验研究,观察其降解速度变化及组织反应情况,为临床应用于多发性肋骨骨折固定材料提供实验依据。方法将纯PCL和蚕丝纤维增强PCL植入兔背部脊柱两侧皮下和肌肉之间,于2、4、8、12、16、24周取材,分别测试2种材料的生物吸收率、组织学观察（HE染色）和扫描电镜观察。结果蚕丝纤维增强PCL在体内植入过程中生物吸收率大于纯PCL,材料内部结构断裂融合降解明显,未见材料周围组织变性、坏死或异常增生现象。结论蚕丝纤维增强PCL多孔复合材料植入体内后具有合适的降解速度,异物反应小,是具有良好应用价值的新型肋骨骨折内固定材料。     

壳聚糖在过氧化氢存在下的氧化降解

主要研究了壳聚糖在H_2O_2存在下的氧化降解反应,分别讨论不同的pH值、H_2O_2浓度、温度和反应时间对降解反应影响。实验结果表明用H_2O_2使壳聚糖降解是制备低分子量可溶性壳聚糖的一种有效和简便的方法。     

Potential Improvement in the Shelf Life of Parenterals Using the Prodrug Approach: Bacampicillin and Talampicillin Hydrolysis Kinetics and Utilization Time

The utilization time for a parenteral prodrug solution with a bioavailable fraction of unity was defined as the time during which the total of the prodrug concentration and the drug concentration equals or exceeds 90% of the initial prodrug concentration. This utilization time was calculated as a function of pH, buffer, and temperature using the experimentally determined rate expressions for bacampicillin and talampicillin. The results were compared to the shelf life of ampicillin solutions under identical storage conditions. First-order rate constants were determined for conversion of the prodrugs to ampicillin (k _c), for -lactam degradation of the prodrugs (k _nc), for the overall loss of prodrugs (k _sum), and for -lactam degradation of ampicillin (k _h) in aqueous solutions at 25.0 to 60.0°C, µ = 0.5, in the pH range 0.90 to 8.4. Loss of bacampicillin proceeded primarily by degradation at pH levels below 4 but was due predominantly to conversion at pH levels above 5. Loss of talampicillin was due primarily to conversion throughout the entire pH range. While the prodrug utilization times were approximately twice the shelf life of ampicillin in acidic solutions, ampicillin was significantly better in neutral solutions. The results illustrate the potential for increased prodrug storage periods when utilization time is defined on the basis of the bioactivity rather than on the prodrug concentration alone.     

Degradation of microcystin-RR by UV radiation in the presence of hydrogen peroxide.

Experiments were conducted to investigate the degradation of microcystin-RR in order to assess the effectiveness and feasibility of the combined UV/H(2)O(2) catalytic system for purification of water polluted by microcystins. The operating parameters such as hydrogen peroxide dosage, pH value, UV light intensity, initial concentration of microcystin-RR and reaction time were evaluated, respectively. The degradation efficiency increased nonlinearly with increasing UV light intensity and hydrogen peroxide dosage, respectively. There existed an optimal hydrogen peroxide dosage, beyond which the reagent exhibited an inhibitory effect, for degrading microcystin-RR. The degradation process could be fitted by both of the pseudo-first-order and second-order kinetics well and primarily followed a mechanism of both direct photolysis and hydroxyl radical oxidation. Compared with the treatment using UV radiation and hydrogen peroxide individually, the combined UV/H(2)O(2) system could significantly enhance the degradation efficiency due to the synergetic effect between UV radiation and hydrogen peroxide oxidation. The observed rate constants decreased and the corresponding half-lives prolonged as the concentrations of microcystin-RR increased. The combined UV/H(2)O(2) process provides an effective technology for the removal of microcystins from drinking water supplies.     

Effects of Ro 31-8220 on smooth muscle cell proliferation induced by fibrinogen degradation products

目的：研究纤维蛋白原降解产物的致有丝分裂原活性及一种新型ＰＫＣ抑制剂Ｒｏ３１８２２０（Ｒｏ）的作用．方法：大鼠主动脉平滑肌细胞增殖采用结晶紫染色法测定．结果：纤维蛋白原降解产物促进大鼠主动脉平滑肌细胞的增殖，Ｒｏ（００１－１μｍｏｌ·Ｌ－１）剂量依赖地抑制增殖．结论：Ｒｏ抑制纤维蛋白原降解产物诱导的平滑肌细胞的增殖．     

苦参碱对纤维蛋白纤维蛋白原降解产物诱导血管细胞损伤、增殖及腹腔巨噬细胞释放IL-1的影响

目的：研究苦参碱（Ｍａｔ）对纤维蛋白纤维蛋白原降解产物（ＦＦＤＰ）作用的影响。方法：大鼠主动脉内皮细胞损伤以乳酸脱氢酶释放测定;大鼠主动脉平滑肌细胞增殖采用结晶紫染色法测定;白细胞介素１活性采用小鼠胸腺细胞增殖法测定。结果：ＦＦＤＰ能促进大鼠主动脉内皮细胞释放乳酸脱氢酶,诱导大鼠主动脉平滑肌细胞增殖,并促使小鼠腹腔巨噬细胞分泌ＩＬ１增加。结论：Ｍａｔ可抑制ＦＦＤＰ的作用。对动脉粥样硬化的防治可能有一定意义。     

龙胆规范化种植中农药世高安全使用标准的研究

目的：制定龙胆规范化种植中农药世高的安全使用标准，以保证其施用安全有效。方法：通过测定农药世高在龙胆生长期的降解动态，计算农药世高在龙胆中的半衰期，从而制定农药世高的安全使用标准。结果：在当地的气候条件下，农药世高在龙胆茎叶上的半衰期为6.84～6.90 d。结论：龙胆规范化种植中，建议农药世高喷施量应小于400 g·hm^-2，安全使用间隔期为40 d。     

溴甲纳曲酮水溶液降解动力学研究

 目的 研究溴甲纳曲酮在水溶液中的降解动力学特征,考察溴甲纳曲酮的降解影响因素,为其制剂的研究提供必要的实验结果和数据。方法 通过经典恒温实验,应用HPLC测定溴甲纳曲酮在不同温度、pH值、光照和Fe³⁺浓度条件下的降解动力学参数,用阿仑尼乌斯公式预测其有效期和活化能。结果 溴甲纳曲酮在水溶液中的降解反应级数为n=1,其水溶液最稳定的pH值在3.51左右;随着温度升高,溴甲纳曲酮降解速率增加,在常温水溶液中的有效期t_0.9=145 d;Fe³⁺和光照能促进溴甲纳曲酮的降解。结论 溴甲纳曲酮在水溶液中的降解属近似一级动力学过程,降解速率与温度成正相关,pH对溴甲纳曲酮的降解有一定的影响,Fe³⁺和光照对溴甲纳曲酮的降解速率影响较明显。为制剂的研发提供了必要的实验结果和数据。     

3.0 T MRI联合血清DR-70检测显著提高早期结直肠癌的诊断效能

目的  探讨3.0 T MRI与血清纤维蛋白降解复合物（DR-70）联合检测在早期结直肠癌诊断中的价值。方法  选取本院2018年8月~2020年8月收治的早期结直肠癌患者96例,另选取同期40例结直肠良性肿瘤患者,实施3.0 T MRI行动态增强和扩散加权成像等序列扫描和血清DR-70检测,利用Spearman相关性分析3.0 T MRI相关参数和血清DR-70水平与早期结直肠癌的关系,并采用ROC曲线评估这两种检测指标对早期结直肠癌的诊断效能。结果  96例患者中本次共检出结直肠癌94例,漏诊2例,检出率为97.92%;3.0T MRI能较好地观察到肿瘤的病灶部位、形态、侵袭等情况,肿瘤病灶在T1图像呈中等偏低信号,T2图像呈略高信号,动态增强扫描早期呈不均匀强化,延迟期表现为稍低信号,在扩散加权成像中呈明显高信号,在表观扩散系数（ADC）图上呈低信号;观察组MRI参数ADC值低于对照组（P < 0.05）,而DR-70水平高于对照组（P < 0.05）;Spearman相关性分析显示ADC值与结直肠癌呈负相关（r=-0.383,P < 0.05）,而DR-70水平则与结直肠癌呈正相关（r=0.460,P < 0.05）;ROC曲线显示：ADC、DR-70联合诊断结直肠癌曲线下面积为0.850,明显高于各单项指标曲线下面积（P < 0.05）。结论  结直肠癌患者利用3.0T MRI技术和DR-70联合检测能显著提高结直肠癌的诊断鉴别效能。     

Heterogeneous Loss of Connexin43 Protein in Ischemic Dog Hearts

Heterogeneous Loss of Connexin43 Protein in Ischemic Dog Hearts. Introduction: Ischemia causes cell decoupling in the myocardium. Prolonged ischemia activates proteases and causes degradation of structural proteins as well as gap junctions. There is little information about the degradation of gap junction protein during the early time period after acute ischemia. The purpose of the present study was to investigate connexin43 (Cx43) protein degradation and distribution patterns in (he canine left ventricular wall during 1 to 6 hours of ischemia. Methods and Results: Ischemia of canine left ventricular myocardium was induced by ligation of the left anterior descending coronary artery. Following a period of in situ ischemia of up to 6 hours, samples were harvested, and standard paraffin slides were prepared for Cx43 and wheat germ agglutinin double labeling. Cx43 distribution was visualized by confocal microscopy. In controls, homogeneous distribution of Cx43 staining was determined. Ischemia caused a loss of Cx43 with a heterogeneous pattern by mixing foci of infarcted cells among normal cardiac myocytes. To determine if the changes were induced by heterogeneous reduction in the blood supply, an in vitro ischemic model was studied to induce more homogeneous ischemia. Western blot analysis of these in vitro ischemic tissue samples revealed a reduction of Cx43 protein concentration with a 50% decay time of 4.8 hours. Cx43 dephosphorylation was detected after 1 hour of in vitro ischemia. Heterogeneous loss of Cx43 was found in the in vitro ischemic tissue. There were no. significant changes in Cx43 staining density during the first hour of ischemia at a time when dephospharylation of the protein was observed. After 1 hour of ischemia, Cx43 was reduced at intercalated disk areas, and. after 6 hours, most Cx43 disappeared at intercalated disk areas, while small amounts of Cx43 remained at side-to-side junctions. Conclusion: Cx43 undergoes both distribution and concentration changes following acute cardiac Ischemia. The loss of Cx43 protein is heterogeneous. Cx43 dephosphorylation occurred within 1 hour following ischemia.