Calculation of Hydrolytic Rate Constants of Poly(ortho ester)s from Molecular Weights Determined by Gel Permeation Chromatography

Purpose. To obtained rate constants from weight-averaged (M_w) or z-averaged (M_z) molecular weights for polymers of Schule-Flory distribution and undergoing random scission. These constants were compared with those obtained by parallel ¹HNMR studies. Methods. The hydrolysis of two poly(ortho ester)s were followed by ¹HNMR and gel permeation chromatography (GPC). Results. Equations to convert number-averaged (M_n), M_w and M_z into fraction of backbone remaining (f_c) were derived. First-order hydrolytic rate constants of two poly(ortho ester)s; DETOSU-HD and DETOSU-CDM were calculated using these relationships. The rate constants calculated from ¹HNMR, M_z and M_w were 0.215, 0.218 and 0.182 hr^–1, respectively, for DETOSU-CDM and 0.152, 0.086 and 0.038 hr^–l for DETOSU-HD. The large discrepancy in the rates determined by ¹HNMR and GPC in the latter case was attributed to that the detector response (refractive index) of the monomers was lower than that of the high molecular weight polymer. The difference is small in the case of DETOSU-CDM, and the rates calculated from GPC data were comparable or nearly identical to that obtained from ¹HNMR data. Conclusions. Although GPC can yield rapid and valuable kinetic data for the degradation of biodegradable polymers, the system, however, must be carefully calibrated to account for the variations in Mark-Houwink coefficients and in the response of the mass detector between the high and low MW polymers.     

Quantitative relationship between pupillary reflex feature and its diopter in retinoscopy

ＱｕａｎｔｉｔａｔｉｖｅｒｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｐｕｐｉｌｌａｒｙｒｅｆｌｅｘｆｅａｔｕｒｅａｎｄｉｔｓｄｉｏｐｔｅｒｉｎｒｅｔｉｎｏｓｃｏｐｙＸｕＳｈａｎｇ（徐上）；ＪｉＳｈａｎｇｎｉａｎ（计尚年）（ＤｅｐａｒｔｍｅｎｔｏｆＯｐｈｔｈ...     

脑肿瘤伴发精神障碍─—附36例分析

９８例颅内肿瘤经手术和病理检查证实，其中３６例脑瘤伴精神障碍，最常见的精神症状是情感淡漠，情感不稳，遗忘，意识模糊，嗜睡、痴呆。为最常见的部位为额顶部和颞叶部。     

Liver transplantation for erythropoietic protoporphyria liver disease.

In erythropoietic protoporphyria (EPP), there is excessive production of protoporphyrin, primarily in the bone marrow, resulting in increased biliary excretion of this heme precursor. Some patients will develop progressive liver disease that may ultimately require liver transplantation. However, excessive production of protoporphyrin by the bone marrow continues after transplantation, which may cause recurrent disease in the allograft. This study was performed to define post-transplant survival, the risk of recurrent disease, and specific management issues in patients transplanted for EPP liver disease. The patients studied consisted of twelve males and eight females, with an average age of 31 (range, 13-56) years at the time of transplantation. The estimated maximum MELD score prior to transplant was 21 (range, 15-29). Unique complications in the perioperative period were light induced tissue damage in four patients and neuropathy in six, requiring prolonged mechanical ventilation in four. Patient and graft survival rates were 85% at 1 year, 69% at 5 years, and 47% at 10 years. Recurrent EPP liver disease occurred in 11 of 17 patients (65%) who survived more than 2 months. Three patients were retransplanted at 1.8, 12.6, and 14.5 years after the initial transplant for recurrent EPP liver disease. In conclusion, the 5-year patient survival rate in patients transplanted for EPP liver disease is good, but the recurrence of EPP liver disease appears to diminish long term graft and patient survival.     

Preservation of the spleen using human fibrin seal

Because of the spleen's role in host defence and the recognition of overwhelming post-splenectomy sepsis, the current aim of treatment for splenic injuries is to preserve the spleen. A number of hemostatic agents have been used in an effort to control bleeding but have not proved satisfactory. The authors report the results of an experiment using a two-component fibrin seal on injured rabbit spleens. In female rabbits a longitudinal laceration of the entire spleen was made. After 2 1/2 minutes of continuous hemorrhaging, the spleens were either not treated (5 rabbits) or treated by splenectomy suture repair or fibrin-seal repair. Hemoglobin values were measured preoperatively and 3 days postoperatively. The greatest number of deaths within 14 days occurred in the untreated group. There was no difference in death rate between the treated groups; similarly, there was no difference in blood loss or fall in hemoglobin values. Fewer adhesions formed in the fibrin-seal group than in the others (p less than 0.02). Histopathological examination revealed a greater fibrinoblastic response in the spleens treated with fibrin seal than in the other groups. The authors believe that fibrin seal is an effective and safe hemostatic agent applicable to splenic parenchymal injuries, and that it promotes wound healing and suppresses adhesion formation.     

白细胞介素-13功能研究进展

白细胞介素－13主要由活化的Th2(CD4^ )细胞分泌，诱导单核巨噬细胞分化及延长寿命；促进MHC－Ⅱ，CD23表达；抑制炎性和趋化因子产生；诱导B细胞增殖，活化，刺激IgM,IgG的产生和重链的转换；使血管细胞粘附分子－1表达；抑制人类免疫缺陷病毒（HIV）复制；间接诱导巨噬细胞和NK细胞参与抗肿瘤作用。在变态反应性疾病和哮喘中引起呼吸道高反应性，嗜酸粒细胞性炎症，粘液分泌过多，基膜纤维化等，其受体是与IL－4Rα形成功能复合体而发挥作用。IL－13信号转导途径除了JAK／STAT6以外，尚有IRS－1,Fes，磷酸激酶，BCL－6／SOCS等途径。     

Regional anaesthesia in ambulatory surgery

Regional anaesthesia provides many advantages and can be practised safely in ambulatory surgery. It provides better postoperative pain control, avoids many complications associated with general anaesthesia and shortens recovery time. However, extra time required, associated complications and acceptance of patients are the factors of concern in practising regional anaesthesia in an ambulatory setting. This review will discuss various regional anaesthesia techniques suitable for outpatients.     

Controlled-release codeine is equivalent to acetaminophen plus codeine for post-cholecystectomy analgesia

PURPOSE: Following ambulatory surgery, long-acting analgesics may provide advantages over short-acting analgesics. This study compared controlled-release codeine (CC) and acetaminophen plus codeine (A/C; 300 mg/30 mg) for pain control in the 48-hr period following laparoscopic cholecystectomy. METHODS: Eligible patients were randomized to CC or A/C in a double-blind, double-dummy parallel group study. Unrelieved pain in hospital was treated with fentanyl i.v. bolus. Pain [100 mm visual analogue scale (VAS)] was assessed before the first dose of medication; at 0.5, one, two, three, and four hours post-dose; at discharge; and three times a day for 48 hr. Adverse events were recorded and measures of patient satisfaction were assessed at the end of the study. RESULTS: Eighty-four patients were enrolled in the study; 42 patients in each group. There were no statistically significant differences between CC and A/C treatment. Mean VAS baseline pain was similar in both groups (P = 0.49) and there was no significant difference in the time to onset of analgesia (P = 0.17). At 0.5 hr, the mean VAS pain score was significantly reduced from baseline in both groups (P = 0.0001). The VAS pain scores at discharge were reduced 59% and 56% from baseline, respectively (P = 0.61). There was no difference between treatments in the incidence of adverse events and patients reported similar levels of satisfaction. CONCLUSIONS: Controlled-release codeine provides an equivalent onset of analgesia, reduction in postoperative pain, and level of patient satisfaction, to acetaminophen plus codeine, over 48 hr following cholecystectomy, with the advantage of less frequent dosing.     

田径运动员最大摄氧量和无氧功测试中血乳酸的应用

目的:研究田径运动员最大摄氧量和Wingate测试后血乳酸的变化,分析血乳酸对测试结果的意义。方法:测试田径短跑运动员36例和中长跑运动员29例的最大摄氧量和Wingate无氧功,以及测试后的血乳酸值。结果:最大摄氧量测试后血乳酸数值为9～11mmol/L左右,摄氧量与乳酸值没有直接相关关系,但不同项目之间有一定的差异;Wingate测试后血乳酸数值一般大于12mmol/L,测试的主要评价指标与乳酸值都有较高的相关关系。结论:血乳酸值对于最大摄氧量测试意义不大,但对于Wingate测试可以作为一项辅助评价指标。