Dextranase can degrade dextran polymer into low molecular weight polysaccharide. Dextranase and its hydrolysates are widely used in food, medicine and chemical industries. Studies on dextranase progresses rapidly in recent years. We reviewed literature reports combined with our study about the progress of dextranase and its potential applications in industry. In addition, we addressed hot topics and emphasized on the current research about dextranase, existing problems in domesticstudies and the future research needs needs.
Dextranase ; chemistry ; Dextrans ; chemistry ; Molecular Weight ; Polymers

The experimental teaching of Pharmaceutical Technology plays a critical role in improving the students' knowledge conversion,application,and innovation abilities in pharmaceutical engineering specialty.According to the problems existing in experimental teaching process,exploration and practice on the case teaching method and the student-centered teaching mode are introduced in this paper.The implementation of the teaching reform can effectively combine pharmaceutical technology theory with practice,and is conducive to the professional development of pharmaceutical engineering in our university.

Objective To explore the effect of intensity of 1 Hz repetitive transcranial magnetic stimulation (rTMS) to right Broca's ho-mologue on nonfluent aphasia after stroke. Methods 40 inpatients were equally divided into low-intensity group and high-intensity group, who received rTMS (1 Hz for 10 minutes) once a day and twice a day respectively for 10 days. They were assessed with Western Aphasia Battery (WAB) before and after intervention, and 2 months after intervention. Results The scores of content and fluency, auditory compre-hension, naming, repetition and AQ improved more in the high-intensity group than in the low-intensity group (P<0.01). It maintained more for 2 months in the scores of content and fluency, repetition and AQ (P<0.05). Conclusion High-intensity rTMS can promote the improve-ment of speech in patients with nonfluent aphasia after stroke that remains for a long term.

Objective:To see the influence of different antiplatelet therapies on stroke patients’ readmission by performing a deep data-mining into Beijing Healthcare Insuring Database,based on a large sample size.Methods:Aretrospective cohort study,was adopted to extract patients primarily diag-nosed as ischemic stroke from healthcare database.The first hospital records were considered as the pa-tient’s baseline in this study,who were divided into MAPT (aspirin)and DAPT (aspirin and clopi-dogrel)according to the patient’s baseline medications.A follow-up was conducted to see whether the patients would have rehospitalization record because of major result events after medication.The major re-sult events,included:(1 )recurrence of ischemic stroke;(2)hemorrhagic transformation of ischemic stroke;(3)myocardial infarction;(4)the digestive hemorrhage.The Kaplan-Meier figure was used to compare the survival situations between these two groups,the log-rank test was used to test the difference of the survival curve,and 1 ∶1 propensity score matching was calculated from the patients’baseline da-ta.Cox proportional hazards model was used to calculate the hazard ratio (HR).Results:A total of 27 695 patients From January 201 0 to September 201 3 were included,4 047 with DAPT,and 23 648 with MAPT.Because the baseline characteristics of the patients was disequilibrium,so we used 1 ∶1 pro-pensity score matching,after which,the number of the two groups was 4 046 each.Adjusted for the gen-eral demographic characteristics such as age,sex,nationality,complication and drug combination,no statistical significance was observed between the survival curves of the two groups (P =0.06).HR value of major result events between the groups was 0.91 (0.82 -1 .01 ,P =0.07),which was not statistically significant.The covariate gender HR =1 .36 (1 .20 -1 .55,P <0.05),accompanied by diabetes HR =1 .36 (1 .20 -1 .54,P <0.05 ),dyslipidemia HR =1 .1 3 (1 .00 -1 .27,P =1 .1 3),heart disease HR =1 .39 (1 .22 -1 .58,P <0.05)was statistically significant.Drug combination with other antiplate-let agents HR =1 .05 (0.95 -1 .1 7,P >1 .05)did not increase the risk of readmission.Conclusion:There was no difference in prevention of readmission between patients with DAPT and MAPT.Patients with complications should actively treat the complications at the same time as they prevent recurrence after first attack.

Objective To explore the effect of acupuncture on stroke patients in hemiplagic spasm period.Methods63 stroke patients in hemiplagic spasm period were randomly divided into the electro-acupuncture group(n=31) and control group(n=32).All patients of two groups received routine rehabilitation training,but those of the electro-acupuncture group were added with electro-acupuncture at "Zusanli"(ST36).The composite spasticity scale(CSS) score,H/Mmax and muscular compliance of two groups before and after treatment were observed and compared.ResultsThe CSS scores and H/Mmax and grading gastrocnemius muscular compliance of the electro-acupuncture group were superior to that of the control group(P<0.05～0.01).ConclusionAcupuncture can decrease muscular tension and increase motor function of stroke patients in hemiplagic spasm period.

Carotid atherosclerotic plaque rupture and thrombosis are the independent risk factors of acute ischemic cerebrovascular disease. Early identification of vulnerable plaques provides the evidence for early intervention in patients with asymptomatic carotid artery stenosis, and also helps to reduce the recurrence risk in patients with symptomatic carotid artery stenosis. This article focuses on comparing the advantages and limitations of the available clinical imaging methods in identifying vulnerable carotid artery plaque, and provides relevant prognostic indicators for patient risk stratification in clinical work.

Objective To explore the effect of low frequency repetitive transranial magnetic stimulation (rTMS) on unilateral spatial neglect (USN). Methods 40 stroke patients with USN were divided into treatment group (n=20) and control group (n=20). Patients in the treatment group were treated with low frequency rTMS for 2 weeks. The USN degree of these groups were evaluated before and after the treatment. Results There was no significant difference of USN degree between these groups before the treatment (P>0.05); Compared with the control group, the treatment group improved significantly after the treatment (P<0.05). The USN degree of patients in the treatment group decreased significantly after the treatment (P<0.05), while patients in the controlled group had no difference (P>0.05). Conclusion USN induced by stroke could be improved obviously through low frequency rTMS.

Background: and Purpose As a leading cause of disability and death in China, stroke as well as its epidemiologic features have gained increasing attention. Prior studies, however, have overgeneralized the north-to-south gradient in China. Whether the differences exist across urban and rural areas remains unexplored. This study therefore aims to investigate the north-to-south gradient in stroke incidence across urban and rural China. Methods: The present prospective cohort study analyzed data from the China Health and Nutrition Survey 1997 to 2015. By including 16,917 individuals from diverse social contexts, we calculated the age-standardized incidence of stroke across regions and the age-adjusted risk ratio (aRR). Cox proportional hazards models with time-varying covariates were employed to analyze variations in incident stroke. Results: During the follow-up, age-standardized incidence of stroke ranged from 4.17 per 1,000 person-years (95% confidence interval [CI], 3.38 to 4.96) in the north region to 1.95 (95% CI, 1.60 to 2.30) in the south region (aRR, 2.04; 95% CI, 1.58 to 2.64; P<0.001). The north-to-south gradient of stroke incidence was observed only in rural areas, but not in urban areas. Hierarchical modelling analyses further indicated that the regional differences could be mostly explained by the disparities in the prevalence of hypertension. Conclusions The present study extends the current evidence on the north-to-south gradient by demonstrating that the difference varied across urban and rural China. Our findings highlight the importance of hypertension management as the measure for alleviating regional differences in stroke incidence.

Objective To explore the application value of dazzle speed dual-source dual-energy CT imaging in head and neck arteries. Methods Total 96 patients were enrolled into two groups randomly in this study. Fourty-eight pa tients were scanned the dual-energy scanning mode (140 kV/Sn80 kV,210/105 mAs) in group A. The other 48 patients were scanned in a tranditional Neuro-DSA mode (120 kV/245 mAs) in group B. The CT volume dose index (CTDI vol) and the subjective image quality score were compared between two groups. Results The difference of the subjective im age quality score was significant between the two groups(P<0.05), the effective dose of group A was decreased by 25%compared with the dose of group B [(7.54±0.05) mGy vs (10.67±0.08) mGy). Conclusion Radiation dose is lower, image quality is better in the dazzle speed dual-source double energy imaging of the head and neck vascular when compared to the conventional Neuro-DSA imaging. But excessive?subtraction angiography exists in the bone of the skull base, the technology needs to be improved.

Objective:To explore the short-term outcomes of reconstruction of tumorous critical bone defects at femoral shaft with a 3D printed ultra-short stem with a porous structure.Methods:From September 2016 to June 2018, 8 patients underwent reconstruction of critical bone defects with a 3D printed ultra-short stem with a porous structure after resection of femoral shaft malignant tumor at Department of Orthopaedics, West China Hospital. There were 4 males and 4 females, with an average age of 36.9 years (from 11 to 61 years). Their preoperative Enneking staging was stage Ⅱb in all. There were 3 osteosarcomas, 2 Ewing sarcomas, 2 chondrosarcomas and one periosteal osteosarcoma. Preoperative CT/MRI image fusion technology was used to define the surgical boundary, design the guide plate and prosthesis, and perform surgical simulation. Tomosynthesis-shimadzu Metal Artefact Reduction technology was used to evaluate osseointegration. Complications and bone oncology prognosis of the patients were documented. The lower limb function of the patients was evaluated using Musculoskeletal Tumor Society (MSTS) 1993 scoring and knee range of motion.Results:The overall follow-up time ranged from 36 to 50 months, averaging 42.8 months. During operation one patient sustained a periprosthesis fracture, the union of which was followed up after wire assisted fixation. There was no local tumor recurrence, lung metastasis or death. The last follow-up revealed good osseointegration and basically isometric lower extremities in all cases. There was no such a complication as aseptic loosening of the prosthesis, deep infection or prosthesis fracture during the follow-up period. At the last follow-up in the 8 patients, the flexion range of the knee joint was 116.2°±9.1°, significantly improved compared with that before operation (98.8°±10.9°), and the MSTS score was (26.2±2.1) points, also significantly improved compared with that before operation [(21.6±1.8) points] ( P<0.05). Conclusions:Reconstruction with a 3D printed ultra-short stem with a porous structure is an accurate operation for femoral shaft tumorous bone defects. With careful preoperative design, intraoperative manipulation and strict postoperative follow-up management, this operation can lead to fine early curative outcomes for long shaft critical bone defects.