AIM: To synthesize biodegradable poly lactic acid (PLA) through the optimization and selection of process and catalyst.METHODS: This experiment was performed at the Research Center for Green Chemistry and Technology in the School of Municipal and Environmental Engineering of Harbin Institute of Technology from February 2003 to October 2004. Biodegradable poly L-lactic acid (PLLA) was synthesis by melt polycondensation using L-lactic acid (LA) as material. Firstly, oligo L-lactic acid (OLLA) was prepared by dehydrating aqueous solution of LA without catalyst. And then, the mixture of OLLA and catalyst was heated at a certain temperature and pressure for a period of time to get the product of PLLA. The structure of PLLA was characterized by Fourier transform infrared (FTIR) spectra and 1H- nuclear magnetic resonance (1H-NMR) spectra. The polydispersity was determined by gel permeation chromatography (GPC).RESULTS: OLLA with the viscosity average molecular weight (Mη) of 6 500 g/mol was prepared by the following steps: the solution of LA without catalyst was dehydrated at 140 ℃, first at reduced pressure of 30 kPa for 2 hours, and then at 5 kPa for 4 hours. SnCl2-p-toluenesulfonic acid (TSA) system was the effective catalyst for the polycondensation of OLLA. After the mixture of OLLA and catalysts polycondensed at 165 ℃ and 5 kPA for about 8 hours, PLLA with the Mη of 65 000 g/mol was obtained by using SnCl2-TSA system as catalyst with the SnCl2 amount of 0.4wt% to OLLA and equal mol ratio of SnCl2 and TSA.CONCLUSION:PLLA with a certain practicability was obtained under the optimal process and catalyst. Oligomerization of LA played an important role on improving the molecular weight of PLLA.

Objective To study the phase correlation of cutaneous multichannel impedance measurements and the contractions, peristalsis of stomach and the conduction properties in space.Methods A spiral gastric body model was rotated to simulate shrinkage and creep of the stomach.In order to verify the feasibility and validity of the multichannel impedance gastric dynamic measurement, experiments with emulation of multichannel impedance gastric motility measuring principle were conducted through three-dimensional simulation on the electrical characteristics of gastric body model in saline tank simulator.Results The emulation results showed that the change of epigastric current density and potential distribution is consistent with the course of moving from top to bottom when lateral edge of model (namely the intumescent location when the stomach is full) after detecting electrodes in sequence.Meanwhile, the measurement voltage wave forms clearly showed the contraction location of stomach after the model rotating for three cycles in a row, and the phase relationship between adjacent measurement channels was also measured.The sixty seconds data acquired by the experiment device proved that voltage wave form of three measurement channels corresponded to the phase relationship of movement status of the gastric body model.Conclusions Cutaneous multichannel wave forms prove a cyclical movement of stomach, and phase difference among the multichannel signals relating to speed of peristaltic wave, position of the measuring electrodes and channel spacing, etc.This study provides simulation and experimental basis for explanation of quantitative study of conduction properties in space and phase relationship between the results of surface multichannel impedance measurements and the contractions, peristalsis of stomach.

Antineoplastic Agents ; administration & dosage ; pharmacology ; Drug Delivery Systems ; Humans ; Liposomes ; administration & dosage ; pharmacology ; Sesquiterpenes ; administration & dosage ; pharmacology

Objective To investigate the serum levels of soluble human leukocyte antigen (sHLA)-G in patients with polymyositis (PM) or dermatomyositis (DM),and to analyze its association with clinical features and possible role in the pathogenesis of PM/DM.Methods Serum sHLA-G levels of 26 patients with PM,70 patients with DM and 35 matched healthy controls were measured by ELISA.The relationship between the sHLA-G levels and clinical features or seroimmunological data in the patients with PM/DM was analyzed.Results Serum levels of sHLA-G in PM/DM patients were significantly higher compared to healthy controls [(44±70) U/ml vs (4±5) U/ml,P＜0.01].There was statistically significant difference between DM patients and PM patients [(54±81) U/ml vs (27±41) U/ml,P=0.004].The incidence of dysphagia was significantly higher in sHLA-G elevated group than those in sHLA-G normal group (P=0.001).Additionally,Spearman rank correlation analysis showed that the serum sHLA-G levels were positively correlated with serum C3 (r=0.284,P=0.021),but negatively correlated with CD3+ T cells (r=-0.233,P=0.047) and CD4+ T cells (r=-0.287,P=0.015) in the peripheral blood in patients with PM/DM.Serum levels of sHLA-G in non-treated PM/DM patients were significantly higher compared to treated patients [(77±99) U/ml vs (34±52) U/ml,P=0.021].No relationship between serum sHLA-G levels and PM/DM disease activity,or different drug therapy was found.Conclusion Serum levels of sHLA-G are increased in PM/DM patients.The increased production of sHLA-G,paralleled with higher incidence of dysphagia and lower level of CD3+ T cells and CD4+ T cells,indicates that sHLA-G may play an important role in the pathogenesis of PM/DM.

Animals ; Cell Culture Techniques ; methods ; Cell Separation ; methods ; Culture Media ; Epithelial Cells ; cytology ; Respiratory System ; cytology ; Swine

[ ABSTRACT] AIM:To investigate the effect of atorvastatin on the development of heart failure after myocardial infarction and the association with sodium-calcium exchanger (NCX) expression.METHODS:The model of heart failure was established by ligation of the anterior descending coronary artery for 8 weeks.The rats were randomly divided into con-trol group, heart failure group, and atorvastatin group.Either atorvastatin (10 mg· kg-1· d-1) or vehicle was orally ad-ministered to the rats on the next day after the surgery .The left ventricular function and NCX expression were analyzed 8 weeks after ligation .Neonatal rat cardiomyocytes were cultured to investigate the effect of atorvastatin on the changes of cal -cium concentration induced by hypoxemia .RESULTS: A decrease in left ventricular diastolic dimension , an increase in left ventricular fractional shortening , and reductions of BNP level and NCX expression were observed in atorvastatin group . The hypoxemia-induced calcium overload in cultured cardiomyocytes was inhibited by atorvastatin , and it was inhibited by the inhibitor of NCX .CONCLUSION:Atorvastatin treatment improves cardiac function , which may be related to the ex-pression and function of sodium calcium exchanger in heart failure .

Background Diabetic complication is associated with lipid peroxidation.Aldehyde dehydrogenases (ALDH) catalyze the irreversible oxidation of a variety of biological aldehydes,including lipid-derived aldehydes (LDAs),and thus protect organs and tissues from toxic LDAs.Understanding the activity of ALDH in different ocular tissues in diabetic subjects is very important for prevention and treatment of diabetic ocular complications.Objective This research aimed to investigate the activity and expression of ALDH in different ocular tissues in diabetic rats and to explore the mechanism of ALDH in diabetes-induced eye disease.Methods Twenty-eight healthy SPF male Sprague-Dawley(SD) rats weighted 170-180 g were randomly divided into the normal control group and diabetic group.The diabetic animal model was established by intraperitonial injection of 4％ streptozotocin at 65 mg/kg.Isometric citric acid buffer was injected in the rats of the normal control group.The rats were sacrificed in each group 2 and 4 months after the establishment of the diabetic models,and eyeballs were obtained for the preparation of corneal,lens and retinal homogenates.ALDH activity was detected using a multifunctional microplate reader SpectraMax M5,and ALDH content was measured by ELISA at the wavelength of 450 nm with the SpectraMax M5 ELISA reader.Results The blood glucose level in diabetic rats was significantly elevated at various time points compared with the normal control group(P=0.000),and body weights were evidently lower in the diabetic group than in the normal group (P =0.000).The activities of ALDH (A340) in corneal,lens and retinal tissues in the diabetic group were increased in comparison with the normal control group (F =396.601,P=0.000),and showed an enhancement with the lapsing of time (F =53.139,P =0.000).In addition,the highest level of ALDH was found in the cornea and the lowest level in the lens(F =6973.000,P=0.000).The expression level of ALDH in the corneal,lens and retinal homogenates was significantly higher in the diabetic group compared with the normal control group (F=312.985,P =0.000) and showed a considerable increase over the course (F =19.203,P=0.000).The highest expression level was seen in the cornea and the lowest was in the lens,with a significant difference among these three kinds of tissues (F =3243.000,P =0.000).Conclusions ALDH can protect ocular tissue from the damage of lipid peroxidation.Thess results suggest that ALDH plays a role in preventing diabetes-related ocular complications.

ObjectiveTo investigate the clinical significance of peripheral blood lymphocyte subsets in patients with idiopathic inflammatory myopathy (ⅡM).MethodsPeripheral blood lymphocyte subsets was determined by flow cytometry in 89 patients with polymyositis(PM ) or dermatomyositis ( DM ).The association between clinical features and peripheral blood lymphocyte subsets was analyzed by F test,t test and x2 test.ResultsPatients with active DM showed significant decreases in counts of CD3+ cell,CD3+CD4+ cell and CD3+CD8+ cell[(8±4),(5.4±2.8) and (2.6±1.6) ×108/L respectively],compared with those in inactive DM [(16±6), (10.4±5.6) and (5.6±3.8) ×108/L respectively] and healthy controls [(14±4), (8.3±2.8) and (4.6±1.7) ×108/Lrespectively](F=12.901,8.257,7.084; P＜0.05).Logistic regression analysis indicated that myositis disease activity could influence the counts of peripheral blood CD3+ cell,CD3+CD4+ cell and CD3+ CD8+ cell (b=0.211,0.344,0.289; P＜0.05 ).ILD in ⅡM could influence the counts of CD3+ cell and the ratio of CD3+CD4+cell (b=0.928,1.974; P＜0.05 ).Logistic regression analysis indicated that the count of CD3+CD8+ cell was risk factor for death,and the relative risk was 0.989(b=-0.011 ; P＜0.05).ConclusionPeripheral blood lymphocyte subsets may be regarded as useful laboratory parameters for monitoring RA disease activity.Decreased CD8+ T cell may predict a poor outcome of patients with IIM.

Objective To study the protective mechanism of adenosine on intestinal barrier function in acute hemorragic necrotizing pancreatitis (AHNP) pigs; Methods Twelve small pigs were equally devided into two groups randomly after the AHNP model sitted up: (1) AHNP controll group (group A) and adenosine treated group (group B). The intestinal blood flow, intestinal permeability, bacterial culture and endotoxin in portal blood were compared between the two groups in pre and post AHNP. Results (1)The intestinal blood flow was dramatically decreased in group A, and much higher in group B than that in group A at the 8 h, 24 hour and day 7 after ANHP model was setted up (P0.001,P

Objective:To evaluate the clinical value of Truview~(TM)EVO_2 optic laryngoscope by comparing it with the Macintosh laryngoscope in patients receiving cervical vertebral surgery.Methods:One hundred patients scheduled for elective cervical vertebral surgery were enrolled in this randomized crossover study.After induction,the patients'glottis in group A (n=50)was displayed by Macintosh laryngoscope and the Cormack-Lehane(C/L)grade was recorded,and then optic laryngoscope was employed to display the laryngeal structure.The order of laryngoscopy attempts was reversed in group B(n= 50).Parameters recorded included demographics,airway assessment feat ures(BMI,thyromental distance,mandibular size,mouth opening,mallampati oropharyngeal scale,and neck movement),C/L grade,laryngoscopic force applied,duration of intubation, difficulties of laryngeal view and injury of upper airway.Results:There were no significant difference in demographics,airway assessment features,C/L grade and duration of intubation between the 2 groups,whereas the laryngoscopic force in group A was significantly lower than that in group B(P