Rheological properties of compound carrageenan / 药学学报

The rheological properties of six compound gels that consists of kappa carrageenan (KC) and another excipient such as konjac gum were explored through comparison of their viscosity measured by the rotation method. The gel fluid type was dependent on the rheological curve fitted by the power-law equation. The effect of concentration on the viscosity of different compound gels was investigated by establishing the linear equation between their viscosity and concentration, the slope of which was used to determine the relation between viscosity and concentration of different compound gels. The viscous flow activation energy (Eη) was calculated by the Arrhenius equation, which was able to investigate the effect of temperature on their viscosity. The interaction between monomer and compound gels was also studied by measuring their viscosity. The results showed that six compound gels were pseudoplastic fluid. Among all compound gels, the KC-xanthan gum (KC-XG) solution exhibited the most obvious shear thinning, the strongest pseudoplasticity, while the smallest Eη, resulting in the best thermal stability of viscosity. Furthermore, the concentration of KC-sodium hyaluronate (KC-HA-Na) solution affected its viscosity significantly. The viscosity of six compound gels was greater than the summation of the two kinds of monomer gels, which suggests that there is a synergistic-viscosity interaction between KC and another excipient.

Three-dimensional finite element modeling and stress analysis on different posts and cores for repairing the maxillary central incisors / 医用生物力学

Objective To establish four finite element models for repairing root canals of the maxillary central incisors, study the influences from different post and core materials as well as root canal rehabilitations on stress distributions of the maxillary central incisors, so as to provide theoretical references for clinical application. Methods Four finite element models of repairing system were established by CBCT scanning, Mimics software, Rapidform.xor3, Solidworks and Ansys Workbench software. The occlusal loads were simulated and Von Mises stresses on the roots were calculated. Results Four precise 3D finite element models for repairing maxillary central incisors were established, including dentin, all ceramic crow, coping crown, post and core, gutta percha point, periodontal ligament, glue and alveolar bone. The analysis found out that different post and core materials as well as glues had different influences on Von Mises stress of the dentins as the greater elastic modulus of the post was, the smaller Von Mises stresses of the dentin would be. The Von Mises stress on the post and core made of cobalt-chromium alloy was 23.15 MPa, which was the smallest. Conclusions Stress distributions on repairing systems of the maxillary central incisors with different post and core materials can be predicted by establishing such different finite element models and provides a basis for the clinical application of maxillary central incisors repair systems.

Liver support therapy with molecular adsorbents recirculating system in liver failure: a summary of 252 cases from 14 centers in China / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>A liver support therapy, named molecular adsorbents recirculating system (MARS), has been used for more than 700 liver failure patients in China. We made here a summary to evaluate the effects of MARS treatment in different applications with emphasis on hepatitis B virus (HBV) based liver failure.</p><p><b>METHODS</b>This report analyzed data of 252 patients (mean age (44.9+/- 12.7) years) in three groups: acute severe hepatitis (ASH), subacute severe hepatitis (SSH) and chronic severe hepatitis (CSH). The largest group was CSH (156 patients, 61.9%), and 188 patients (74.6%, 188/252) were infected with HBV.</p><p><b>RESULTS</b>MARS treatments were associated with significant reduction of albumin bound toxins and water-soluble toxins. Most of the patients showed a positive response with a significant improvement of multiple organ function substantiated by a significant increase in prothrombin time activity (PTA) and median arterial pressure (MAP). There was a decrease in hepatic encephalopathy (HE) grade and Child-Turcotte-Pugh (CTP) scale. Thirty-nine of 188 HBV patients (20.7%) dropped out of the commendatory consecutive therapy ending with lower survival of 43.6% while the rest of the 149 patients had a survival rate of 62.4%. Survival within the ASH and SSH groups were 81.2% and 75.0%, respectively. In the CSH group, end stage patients were predominant (65/151, 43%), whereas the early and middle stage patients had a better prognosis: early stage survival, including orthotopic liver transplantation (OLT) survival of 91.7%, middle stage survival of 75%, end stage survival of 33.8%.</p><p><b>CONCLUSIONS</b>MARS continues to be the most favorable extracorporeal treatment for liver support therapy in China for a wide range of conditions, including the majority of hepatitis B related liver failure conditions. The appropriate application of MARS for the right indications and stage of hepatic failure, as well as the fulfillment of prescribed treatments, will lead to the optimal therapeutic result.</p>

Investigation on the alteration of hepatitis B virus (HBV) markers in liver allograft of HBV related recipients in perioperative period / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the alteration of HBV markers in liver allograft of HBV related recipients pre and post liver transplantation under Lamivudine or combination of Lamivudine with HBIG prophylaxis and explore the mechanism of HBV de nova infection in liver allograft after orthotopic liver transplantation, as well as seek to establish a optimal prophylactic protocol.</p><p><b>METHODS</b>The serial liver biopsy specimens of 90 liver allograft and sera of 78 liver transplant recipients during operation and after 1 week, 1 month, 3 months, 6 months, 12 months, 24 months post transplantation have been collected and detected for HBV markers with enzyme-linked radioimmunoassay, fluorescent quantitative assay for HBV-DNA in serology and with immunohistochemistry stain, HBV-DNA in situ hybridization in histology for detection of HBV markers in liver allograft samples.</p><p><b>RESULTS</b>Whether recipients with active replicative or inactive replicative HBV preoperatively, none of positive HBV-DNA, HBsAg and HBcAg in 100% liver biopsy specimens with HBV-DNA hybridization in situ and immunohistochemistry stains in histology within 2 hours after reperfusion.</p><p><b>CONCLUSION</b>Whatever HBV replicative status the recipients have before surgery, no evidence of HBV particles direct invasion to the liver allograft from HBV related cirrhotics during operation under current prophylactic measures. However, the further supposed mechanism and its significance in HBV de nova infection of liver allograft remained to be disclosed further.</p>

Early indexes to predict the therapeutic effect of interferon on chronic hepatitis B / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To summarize the clinical changing characters of the clinical markers after interferon treatment in chronic hepatitis B (CHB) and make out practical indexes to predict the effect.</p><p><b>METHODS</b>150 CHB patients were randomly divided into two groups: therapeutic group (90) and control group (60) in the prospective controlled trial. The levels of endogenous interferon before treatment, interferon antibody at the end of the second month and fourth month after treatment, alanine aminotransferase (ALT) and HBV DNA in the serum were detected. Then the data was analysed to find out indexes for predicting the effect.</p><p><b>RESULTS</b>(1) The clearance rate of HBeAg had no significant difference in age except for 20 - 30 and 30 - 40 (t > 2.331 2, P < 0.01). (2) It was more effective if ALT level was higher than 400 U/L before treatment and it decreased more than 50% two months after treatment. (3) The patients whose HBV DNA was negative (dot hybridization) or less than 10(6) copies/ml before treatment had higher rate of HBeAg clearance. (4) There was no effect on patients whose interferon antibody turned positive at the end of the second month. (5)A predictive method of comprehensive factors was made out, whose sensitivity, specificity, and accuracy were 80%, 100% and 90%, respectively.</p><p><b>CONCLUSION</b>The clinical characters of these Chinese patients are different from those of the westerners and the effects of interferon have close relation to the levels of ALT, HBV DNA and interferon antibody.</p>