Classification of early infection interfaces associated with existing implants and its clinical application / 中华创伤骨科杂志

Objective To introduce a classification of infection interfaces associated with existing implants which was used to guide the treatment algorithms for implants and infection.Methods From January 2006 to April 2016,197 patients were treated at Department of Bone Tumor Osteopathology,Zhengzhou Orthopaedics Hospital for early infection associated with an existing implant.They were 147 males and 50 females,aged from 12 to 63 years (average,47.3 years).After bacterial cultures and drug sensitive tests and other laboratory examinations,their infection interfaces were classified into 3 types.In type Ⅰ of 89 cases,the infection was confined to the soft tissue and spread to only part of the implant;in type Ⅱ of 75 cases,the infection spread to the internal implant but ended at the implant and bone surface,involving no intramedullary cavity;in type Ⅲ of 33 cases,the infection spread to the intramedullary cavity with defects at broken ends.In primary surgery,plating was performed in 126 cases,external fixation in 48 and intramedullary nailing in 23.Type I cases were treated by systemic intravenous infusion combined with local antibiotic therapy and/or limitedly extended debridement while the implants were reserved,type Ⅱ cases by extended debridement while the implants were reserved,and type Ⅲ cases by extended debridement and external fixation while the implants were removed.Antimicrobial therapy was conducted before and after surgery according to their pathogen examination results.Antibiotics were used after surgery according to their pathogen examination results.Their therapeutic outcomes were evaluated according to their systemic and local symptoms,signs,blood routine indexes,erythrocyte sedimentation rate and level of C reactive protein.Results All the patients were followed up for 2 to 5 years (mean,3.4 years).After antibiotic therapy,debridement and vacuum sealing drainage,the implants were reserved in 150 cases,of which 84 were type I and 66 type Ⅱ,and removed in 47 cases,of which 5 were type Ⅰ,9 type Ⅱ and 33 type Ⅲ.By the criteria described in Surgery for Pyogenic Infection of Bone and Joint,the therapeutic outcomes were rated as cured in 185 cases,as effective in 7 and ineffective in 5.Conclusions A classification of infection interfaces associated with existing implants is significant for scientific,reasonable,standardized and individualized treatment algorithms for implants and infection,avoiding not only incidence of osteomyelitis but also unnecessary removal of implants with effective control of inflammation.

Bone formation mediated by local administration of thymosin β4 in distraction osteogenesis / 中华创伤骨科杂志

Objective To explore the effect and mechanism of local administration of thymosin β4 (Tβ4) on bone regeneration in a distraction osteogenesis model of rat fenur.Methods Sixty Sprague-Dawley rats were randomly divided into groups A,B and C in this study.A distraction osteogenesis model was established in the left femur after osteotomy.At the end of distraction period,the bone regeneration area in group A was subjected to no treatment,that in group B to injection of phosphate buffer saline (PBS),and that in group C to injection of Tβ4.On days 22,29 and 43 postoperatively,the rats from each group were randomly sacrificed and processed for observation of bone regeneration in the distraction osteogenesis area using radiography,Micro-CT,histology and immunohistochemical staining.RT-PCR was used to detect the expression of related genes as well.Results Radiography revealed that the bone regeneration in group C was superior to that in groups A and B on days 22,29 and 43 postoperatively.Micro-CT examination showed significantly increased bone volume (BV),bone mineral density (BMD) and ratio of bone volume to tissue volume (BV/TV) in group C on days 22,29 and 43 postoperatively,and significantly decreased ratio of bone surface area to bone volume on postoperative day 43 in comparison with groups A and B(P ＜ 0.05).HE staining indicated that local capillary density was significantly higher in group C than in groups A and B after local administration of Tβ4 in the distraction osteogenesis.Immunohistochemical staining showed that the capillary density and osteoblasts in group C were higher than in groups A and B.RT-PCR results revealed significantly higher expression of eNOS and Osterix mRNA in the local callus in group C on postoperative day 22 than in groups A and group B (P ＜ 0.05).Conclusion Local administration of thymosin β4 may promote bone formation,which is probably related to the increased expression of eNOS and Osterix.

Management of metacarpophalangeal bone defects after hand trauma by distraction osteogenesis with mini external fixation / 中华创伤骨科杂志

Objective To evaluate the outcomes of distraction osteogenesis with mini external fixation in management of metacarpophalangeal bone defects after hand trauma.Methods From June 2010 to December 2015,16 patients with metacarpophalangeal bone defects after hand trauma received distraction osteogenesis at our department.They were 11 men and 5 women,from 20 to 45 years of age (average,32.5 years).There were altogether 20 bone defects:8 cases had single metacarpal bone defect,2 unilateral second and third metacarpal bone defects and 6 phalangeal shortening after repair of digital stump (involving thumb in 4 cases,index finger in one and index and middle fingers in one).The metacarpophalangeal bone defects averaged 1.8 cm (from 1.0 to 3.1 cm).Under the fluoroscopic guide,4 or 6 mini half-pins in one line were directly drilled into the dorsal aspect of the involved metacarpophalangeal bone before the Orthofix fixator was mounted.The proximal (18 digits) or distal (2 digits) osteotomy between the second and third pinholes was performed via the dorsal approach,The external fixator and pins were removed without anesthesia after callus maturation.Results Average follow-up period was 12.2 months (range,from 9 to 26 months).All the metacarpal bone defects were reconstructed and all the phalangeal shortenings were lengthened;the bony callus was completely calcified at the lengthened part.The mean lengthening was 1.9 cm (from 1.0 to 3.1 cm);the percentage of lengthening ranged from 26％ to 51％ (average,34％).The bone lengthening index (time cost by average 1 cm) was 70.9 d/cm (from 60.0 to 87.1 d/cm).According to the Tentative Assessment Criteria for Upper Extremity Function by Hand Surgery Society,Chinese Medical Association,the total activity of motion (TAM) was excellent in 13 cases,good in 4,fair in 2,and poor in one,yielding an excellent to good rate of 85.0％.Conclusion Distraction lengthening using mini external fixation is a valid option with a minor rate of complications which allows for early functional exercise to help restore the appearance and function of the affected fingers.

Mechanism of genuineness of Glycyrrhiza uralensis based on SNP of β-Amyrin synthase gene / 药学学报

β-Amyrin synthase (β-AS) genes of Glycyrrhiza uralensis from 6 different regions were analyzed by PCR-SSCP and sequenced, then the correlationship between β-AS SNP and regions of Glycyrrhiza uralensis were determined. According to the 1 coding single nucleotide polymorphism on the first exon of β-AS gene at 94 bp site, Glycyrrhiza uralensis could be divided into 3 genotypes. In these genotypes, the percentage of 94A type in genuine regions was much higher, and it had significant differences with the percentage in non-genuine regions (P < 0.001). The results of the experiment proved that different β-AS genotypes at 94 bp site from different regions may be one of the important reasons to result in the genuineness of Glycyrrhiza uralensis.

Enhancing the accumulation of beta-amyrin in Saccharomyces cerevisiae by co-expression of Glycyrrhiza uralensis squalene synthase 1 and beta-amyrin synthase genes / 药学学报

Glycyrrhiza uralensis Fisch. ex DC is widely used in traditional Chinese medicine (TCM). Among its various active components, glycyrrhizic acid is believed to be the marker component. Squalene synthase (SQS) and beta-amyrin synthase (beta-AS) are key enzymes in the biosynthetic pathway of glycyrrhizic acid in G uralensis. To reveal the effects of co-expression of SQS1 and beta-AS genes on this pathway, 7 yeast expression vectors harboring different SQS1 variants and beta-AS were constructed and expressed in Saccharomyces cerevisiae as fusion proteins. TLC and GC-MS results showed that co-expression of SQS1 and beta-AS enhanced the accumulation of beta-amyrin. The effects of SQS12 were more obvious than the other two SQS1 variants. This study is significant for further investigations concerned with exploring the biosynthesis of glycyrrhizic acid in vitro and strengthening the efficacy of G. uralensis by means of increasing the content of glycyrrhizic acid.

Cloning and characterization of a cDNA coding 3-hydroxy-3-methylglutary CoA reductase involved in glycyrrhizic acid biosynthesis in Glycyrrhiza uralensis / 药学学报

The roots of Glycyrrhiza uralensis are widely used in Chinese medicine for their action of clearing heat, detoxicating, relieving cough, dispelling sputum and tonifying spleen and stomach. The reason why Glycyrrhiza uralensis has potent and significant actions is that it contains various active secondary metabolites, especially glycyrrhizic acid. In the present study, we cloned the cDNA coding 3-hydroxy-3-methylglutary CoA reductase (HMGR) involved in glycyrrhizic acid biosynthesis in Glycyrrhiza uralensis. The corresponding cDNA was expressed in Escherichia coli as fusion proteins. Recombinant HMGR exhibited catalysis activity in reduction of HMG-CoA to mevalonic acid (MVA) just as HMGR isolated from other species. Because HMGR gene is very important in the biosynthesis of glycyrrhizic acid in Glycyrrhiza uralensis, this work is significant for further studies concerned with strengthening the efficacy of Glycyrrhiza uralensis by means of increasing glycyrrhizic acid content and exploring the biosynthesis of glycyrrhizic acid in vitro.