Anticoagulant chitosan nanoparticles：synthesis, characterization and biological safety / 中国组织工程研究

BACKGROUND:Studies have shown that chitosan and other natural polysaccharides have heparin-like anticoagulant function after sulfonated modification. Sulfonated chitosan has good anticoagulant property because the sulfonate group formed by sulfonated chitosan is similar with the active group of heparin. OBJECTIVE: To prepare the anticoagulant chitosan nanoparticles and to detect its morphology, physical and chemical properties and biological security. METHODS: Chitosan nanoparticles were synthesized by emulsion-chemical cross link. Sulfonated chitosan nanoparticles were synthesized by sulfonation reaction. Its morphology was described by transmission electron microscope. The peak-value change of its specific groups was observed by infrared spectroscopy. (1) Coagulation experiment: Heparin, chitosan nanoparticles and 10, 30 and 50 mg of sulfonated chitosan nanoparticles were added into the blood of Spraque-Dawley rats. The coagulation indicators were detected. (2) Hemolysis experiment: deionized water, physiological saline and 10, 30, 50 g/L sulfonated chitosan nanoparticles extracts were added into 2% red blood cel suspension of rabbits. The hemolysis rate was detected. (3) Cytotoxicity experiments: DMEM medium containing fetal bovine serum and 10, 30, 50 g/L sulfonated chitosan nanoparticle extracts were used to culture human umbilical vein endothelial cels. Cel relative growth rate and toxicity grading were detected after 72 hours. RESULTS AND CONCLUSION: Scanning electron microscopy showed that sulfonated chitosan nanoparticles had good morphology, with a diameter of 50 nm. Infrared spectroscopy showed that the sulfonated replacement occurred.In vitro coagulation experiments showed that sulfonated chitosan nanoparticles had significant anticoagulant effects in a dose-dependent manner. Sulfonated chitosan nanoparticles meet the national safety standard for hemolysis rate of less than 5%, non-induced hemolysis property. Cytotoxicity assays showed that sulfonated chitosan nanoparticles extracts had no significant cytotoxicity, and its biological safety was in line with the national standards.

Abnormal promoter methylation of p14(ARF), p16(INK4a)and BUB3 genes in malignant transformed cells induced by radiation / 中国肺癌杂志

<p><b>BACKGROUND</b>The methylation of tumor suppressor genes is believed to be one of the most important mechanisms of oncogenesis. In order to research the malignant transformed mechanism induced by radiation, the abnormal promoter methylation of p14(ARF) , p16(INK4a) and BUB3 genes are detected in the transformed human bronchial epithelial cells (BEP2D) induced by α-particles.</p><p><b>METHODS</b>Abnormal promoter methylations were detected with methylation specific PCR (MSP). The level of p14 ARF gene transcription was analyzed by using RT-PCR. DNA was purified and transformed and sequenced.</p><p><b>RESULTS</b>p14(ARF) gene was not methylated in BEP2D cells, but was methylated in the malignant transformed BERP35T-1 cells, and the level of its transcription was depressed remarkably in the latter. However p16(INK4a) gene, which shares two exons with p14 (ARF) gene, was not methylated. BUB3 gene was not methylated in BEP2D as well as BERP35T-1 cells and this was further proved by sequencing analysis.</p><p><b>CONCLUSIONS</b>The methylation of two tumor suppressor genes (p14(ARF) and p16(INK4a)) that share two exons and controll cell cycle are not synchronous in the transformed human bronchial epithelial cells induced by α-particles, and the methylated one (p14(ARF)) is repressed in transcription. The gene of mitosis spindle check-point (BUB3) is unmethylated.</p>

AN ANALYSIS OF THIRTY-SIX CASES OF FATAL PULMONARY THROMBOEMBOLISM CONFIRMED BY AUTOPSY / 解放军医学杂志

Objective To determine the clinical characteristics of hospitalized patients who died of pulmonary thromboembolism (PTE) confirmed by autopsy. Methods The medical and autopsy records of 36 cases of autopsy proven fatal PTE in General Hospital of PLA from 1982 to 2001were reviewed. Cases of tumor embolism, fat embolism, and amniotic fluid embolism were excluded from the study. Results Six patients [16 7% (95% confidence interval, 6 4% to 32 8%)] were diagnosed as PTE prior to death. The diagnosis of PTE was significantly lower in patients with COPD or coronary artery disease. No risk factors were noted in only 4 patients (13 9%). Only a minority of patients had pleuritic pain or hemoptysis(8 3% and 11 1% respectively), while a significantly larger proportion of patients (25%, P

MRSA INFECTION IN INTENSIVE CARE UNIT: A REPORT OF 6 CASES / 解放军医学杂志

Objective To explore the strategies of prevention and treatment of MRSA infection in ICU patients. Methods The clinical data of 6 patients with MRSA infection occurring at the same time in ICU were reviewed retrospectively. Results Vancomycin was given in 4 cases, 250mg twice daily, and teicoplanin was given in one case, 400mg once daily. MRSA cultures were negative in 5 cases after antibiotic treatment. Conclusions MRSA infection occurs frequently in ICU patients, and it spreads readily. Antibiotic treatment, isolation and bacteriological monitoring are very important measures for control of MRSA infection in ICU patients. [HS(1*2/3]

BIOCHEMICAL AND CYTOLOGIC CHARACTERISTICS OF 31 PLEURAL EFFUSIONS DUE TO PULMONARY THROMBOEMBOLISM / 解放军医学杂志

10% was found in 5 patients (16%). Mesothelial hyperplasia was found to be significantly higher in patients with PTE than that in the control group (P

The changes in proinflammatory cytokines in the circulation following acute pulmonary thromboembolism in dogs / 解放军医学杂志

Objective In the present study we examined the roles of three proinflammatory cytokines, i.e. tumor necrosis factor-?(TNF-?), interleukin 1?(IL-1?), and IL-8 in the early phase of APTE, and analyze the impact of these cytokines on the systemic circulation. Methods APTE was induced in 7 anesthetized dogs by injecting the thrombus of own blood into the right jugular vein. Seven animals receiving only warm sterile saline served as controls. Arterial serum samples were collected regularly (0h, 0.5h, 1h, 2h, 4h, 6h) and cytokine levels could be measured by radio-immunity assay. Results Introduction of clots into the pulmonary circulation caused significant increase in the mean pulmonary arterial pressure(from 99.1?5.7 to 66.8?15.3mmHg, P

A system for evaluating treatment efficacy and outcome prediction for senile patients with respiratory failure undergoing mechanical ventilation / 解放军医学杂志

Objective On the basis of the Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ), to establish and appraise a new prognostic evaluation system for elder patients with respiratory failure undergoing mechanical ventilation in order to predict hospital mortality in the respiratory intensive care unit. Methods Two hundred and thirty-eight senile patients with respiratory failure having had mechanical ventilation during their hospitalization were retrospectively analyzed. Patients were randomly divided into 2 groups: model group (n=138) and validation group (n=100). Data of model group were analyzed by monofactorial and multifactorial regression analysis to screen the risk factors. Risk factors were given numerical values according to different grades, and complementary scoring system was then established. APACHE Ⅱ system was combined with complementary scoring system with Logistic multiple regression to form SRFMV system, a special evaluation system for the senile patients with respiratory failure undergoing mechanical ventilation. One hundred patients from validation group were evaluated by both SRFMV system and APACHE Ⅱ system, and the results were then compared to assess the validity and reliability of SRFMV system. Oxygenation index, positive end expiratory pressure (PEEP), tidal volume, phlegm quantity and character, and pulmonary auscultation were selected to serve as standard for complementary scoring system. Mortality equation was set up with logistic multiple regression analysis. Results The predication sensitivity and specificity evaluated by SRFMV system in validation group (0.878 and 0.821, respectively) outstripped that evaluated by APACHE Ⅱsystem (0.818 and 0.771, respectively); the area under ROC curve in SRFMV system and the X2 value in Lemesshow-Hosmer statistic (0.911 and 13.77, respectively) also outstripped that in APACHE Ⅱsystem (0.860 and 11.808, respectively). Conclusions SRFMV system is of better sensitivity and specificity, in which the prediction of mortality is closely consistent with the reality. SRFMV system can be applied to obtain valid predictions of relevant outcomes in senile patients with respiratory failure underwent mechanical ventilation.