In recent years, due to the dramatic increase in the number of surgical operations, there has been a clinically significant increase in the demand for medical adhesives capable of cohesion in a moist environment that can overcome blood or tissue fluids in vivo. As the understanding of the mechanisms and key elements of natural adhesion to aquatic organisms continues to develop, a variety of medical adhesives have been developed by mimicking adhesion procedures or utilizing key functional groups. This article will review the classification, adhesion mechanism, use, research progress and development prospects of biomedical adhesives inspired by aquatic organisms octopus and mussels.
Objective To verify the technics of inactivating/removing pathogens in medical chitosan derived from shrimp shell. Methods Possible pathogen species were included according to the raw material of shrimp shell used in production, then bacillus cereus, porcine parvovirus (PPV) and pseudorabies virus (PRV) were selected as indicator pathogens.Pathogen solution was prepared in accordance with Technical Standard for Disinfection. The processing procedure of medical chitosan was analyzed to determine whether the alkal ization of chitin and the filter steril ization of chitosan were capable of inactivating/removing pathogens and their efficiencies were tested. Results Bacillus cereus was removed by 8 184 cfu/ mL after alkal ization and 30 818 cfu/mL after filter steril ization. The average logarithm inactivation value (LIV) of PPV and PRV after alkal ization were equal to or above 4.76 logTCID50/0.1 mL and 6.67 logTCID50/0.1 mL, respectively, and their average LIV after filter steril ization were 2.25 logTCID50/0.1 mL and 3.04 logTCID50/0.1 mL. The alkal ization of chitin inactivated/removed indicator pathogens effectively, while the filter steril ization of chitosan removed bacterial effectually but could not inactivate viruses completely. Conclusion The alkal ization of chitin can be used as the technics of inactivating/removing pathogens during the preparation process of medical chitosan to guarantee the safety of the product.
ObjectiveTo investigate the stability of unilateral fractured vertebral pedicle screw fixation in the treatment of thoracolumbar fracture. MethodsEighteen fresh calf thoracolumbar spine specimens (T11-L3) were obtained to establish the L1 burst fracture models with Panjabi's high speed trauma apparatus, and were divided into 3 groups:pedicle fixation for adjacent upper and lower vertebrae of fractured vertebra (4 pedicle screws in group A), combined with pedicle screw fixation for unilateral fractured vertebrae (5 pedicle screws in group B), and three-level 6 pedicle fixation (group C). Under normal, fractured, and reconstructed conditions, the range of motion (ROM) of adjacent upper and lower vertebrae of fractured vertebra were measured in flexion, extension, bilateral bending, and axial rotation. Axial stiffness under flexion-compression was measured on the MTS-858 testing system. ResultsThere was no significant difference in ROM and axial stiffness under normal and fractured conditions in all directions among groups (P<0.05), indicating load balance in the groups. ROM of groups B and C were significantly less than that of group A under reconstructed condition in all directions (P<0.05), but no significant difference was found between group B and group C (P>0.05). Biomechanical test showed that group B was significantly higher than group A in the axial stiffness value (P<0.05), but difference was not significant between group B and group C (P>0.05). ConclusionTranspedicular fixation of fractured vertebrae can enhance the stability of the spine. Both unilateral and bilateral fractured vertebral pedicle screw fixations have the same stability.
ObjectiveTo systematically review the efficacy between key hole approach versus large trauma craniotomy for patients with hypertensive intracerebral hemorrhage. MethodsSuch databases as The Cochrane Library (Issue 3, 2013), PubMed, EMbase, WangFang Data, CNKI and VIP was searched to identify randomized controlled trials (RCTs) on key hole approach versus large trauma craniotomy for patients with hypertensive intracerebral hemorrhage from January 2005 to June 2013. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data, and assessed the methodological quality of included studies. Then meta-analysis was performed using RevMan 5.2. ResultsA total of 13 studies involving 1 324 patients was included. The results of meta-analysis showed that, key hole approach was superior to large trauma craniotomy with significant differences in the fatality rate (OR=0.29, 95%CI 0.19 to 0.45, P < 0.000 01), incidence of postoperative complications (OR=0.35, 95%CI 0.21 to 0.57, P < 0.000 1), recovery time of consciousness (MD=-4.52, 95%CI-5.84 to-3.20, P < 0.000 01), neurologic impairment score after 1-month treatment (MD=-12.63, 95%CI-16.36 to-8.90, P < 0.000 01), total effectiveness (OR=3.79, 95%CI 2.54 to 5.66, P < 0.000 01), and postoperative living ability (ADL Grade I, Ⅱ). ConclusionKey hole approach is better than large trauma craniotomy for patients with hypertensive intracerebral hemorrhage. Due to limited quality and quantity of the included studies, the abovementioned conclusion still needs to be verified by conducting more high quality studies, especially conducting multicenter blinding RCTs with large sample-size.
Arrhythmia is a kind of common cardiac electrical activity abnormalities. Heartbeats classification based on electrocardiogram (ECG) is of great significance for clinical diagnosis of arrhythmia. This paper proposes a feature extraction method based on manifold learning, neighborhood preserving embedding (NPE) algorithm, to achieve the automatic classification of arrhythmia heartbeats. With classification system, we obtained low dimensional manifold structure features of high dimensional ECG signals by NPE algorithm, then we inputted the feature vectors into support vector machine (SVM) classifier for heartbeats diagnosis. Based on MIT-BIH arrhythmia database, we clustered 14 classes of arrhythmia heartbeats in the experiment, which yielded a high overall classification accuracy of 98.51%. Experimental result showed that the proposed method was an effective classification method for arrhythmia heartbeats.