The impact of simultaneous inoculation of Pseudomonas aeruginosa,Staphylococcus aureus,and Candida albicans on rodent burn wounds

Burn wound infection often involves a diverse combination of bacterial and fungal pathogens. In this study, we characterize the mixed species burn wound infection by inoculating the burn surface with 1 × 10^3/4/5 CFU of Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans in a 1:1:1 ratio. Using the revised Walker–Mason scald burn rat model, 168 male Sprague-Dawley rats (350–450 g) subject to ∼10% TBSA burn injury, with or without inoculation, were evaluated for 11 days after burn. In the wound, P. aeruginosa and S. aureus formed robust biofilms as determined by the bacterial tissue load, ∼1 × 10⁹ CFU/g, and expression of key biofilm genes. Interestingly, within 3 days C. albicans achieved tissue loads of ∼1 × 10⁶ CFU/g, but its numbers were significantly reduced beyond the limit of detection in the burn wound by day 7 in partial-thickness injuries and by day 11 in full-thickness injuries. The pathogenic biofilms contributed to burn depth progression, increased release of HMGB-1 into circulation from injured tissue, and significantly elevated the numbers of circulating innate immune cells (Neutrophils, Monocytes, and Basophils). This robust model of multi-species burn wound infection will serve as the basis for the development of new antimicrobials for combating biofilm-based wound infections.     

Canine electrophysiology of encainide, a new antiarrhythmic drug

Encainide, a new benzanillide derivative with high potency and a good therapeutic/toxic ratio, was evaluated with the use of standard His bundle recording techniques to determine its effects on the cardiac conduction system in closed chest animals. Twenty mongrel dogs weighing 18 to 29 kg were anesthetized with 4 percent chloralose and classified into groups: group 1, a control group and groups 2,3, and 4, which were given 0.3, 0.9 and 2.7 mg/kg body weight, respectively, of encalnide In an intravenous infusion over a 15 minute period. Plasma concentration, blood pressure, surface electrocardiogram and atrlal and His bundle electrograms were recorded before, during and after drug infusion for a total of 120 minutes. Heart rate, A-H and H-V intervals, the QRS complex and Q-Tc interval were measured every 5 minutes during sinus rhythm and with constant atrial pacing. In addition, sinus nodal recovery time and atrial, atrioventrlcular (A-V) nodal and left ventricular refractory periods were measured before and immediately after infusion and every 30 minutes for 2 hours. Peak plasma concentration averaged 450 ng/ml in group 2,1,300 ng/ml in group 3 and 4,000 ng/ml in group 4. Blood pressure was not altered at any dose level throughout the study. The QRS complex and H-V interval were significantly prolonged (P < 0.005) at doses of 0.9 mg/kg and greater. These effects correlated well with plasma concentration. There was no significant change in heart rate, corrected sinus nodal recovery time, A-H interval, Q-Tc Interval atrial, A-V nodal or left ventricular refractory period. It is concluded that, unlike other antiarrhythmic agents, encainide prolongs His-Purkinje system conduction without significantly affecting conduction or refractoriness of other parts of the cardiac conduction system in animals.     

Clinical results after different operative treatment methods of radial head and neck fractures: A systematic review and meta-analysis of clinical outcome

Introduction

There is no consensus on optimal treatment strategy for Mason type II–IV fractures. Most recommendations are based upon experts’ opinion.

Methods

An OVID-based literature search were performed to identify studies on surgical treatment of radial head and neck fracture. Specific focus was placed on extracting data describing clinical efficacy and outcome by using the Mason classification and including elbow function scores.A total of 841 clinical studies were identified describing in total the clinical follow-up of 1264 patients.

Results

For type II radial head and neck fractures the significant best treatment option seems to be ORIF with an overall success rate of 98% by using screws or biodegradable (polylactide) pins.ORIF with a success rate of 92% shows the best results in the treatment of type III fractures and seem to be better than resection and implantation of a prosthesis. For this fracture type the ORIF with screws (96%), biodegradable (polylactide) pins (88%) and plates (83%) showed the best results.In the treatment of type IV fractures similar results could be found with a tendency of the best results after ORIF followed by resection and implantation of a prosthesis.If a prosthesis was implanted, the primary implantation seems to be associated with a better outcome after type III (87%) and IV (82%) fractures compared to the results after a secondary implantation.

Discussion

Recommendations for surgical treatment of radial head and neck fractures according to the Mason classification can now be given with the best available evidence.Level of evidence: IV     

假体置换与切开复位内固定治疗成人MasonⅢ型桡骨头骨折临床结局的系统评价与Meta分析

背景：对于MasonⅢ型桡骨头骨折,采用何种术式治疗一直是争论的焦点。 目的：比较假体置换与切开复位内固定治疗MasonⅢ型桡骨头骨折的术后优良率、并发症、肘关节功能。 方法：计算机检索PubMed（1950/2014-03）、OVID（1950/2014-03）、MEDLINE（1950/2014-03）、EMBASE（1980/2014-03）、CENTRAL（The Cochrane Library,1993/2014）、CBM（1978/2014-03）、万方数据库（1981/2014-03）、CNKI（1979/2014-03）、维普数据库（1989/2014-03）。搜集MasonⅢ型桡骨头骨折假体置换及切开复位内固定的对照研究并加以系统评价。用Revmen 5.1统计学软件进行异质性分析及Meta分析。 结果：本研究最终纳入2篇随机对照试验和7篇临床对照试验,总计344例患者。采用假体置换155例,切开复位内固定189例。假体置换组优良率[OR=3.17,95%CI （1.78,5.65）,P〈0.0001],并发症[OR=0.22,95%CI（0.10,0.50）,P=0.0003],Broberg-Morrey肘关节功能评分[WMD=12.43,95%CI （8.02,16.85）,P〈0.00001]与切开复位内固定组相比,均有明显优势。 结论：现有的有限证据表明,通过优良率、肘关节功能评分及并发症评价证实人工假体置换治疗MasonⅢ型桡骨小头骨折较切开复位内固定具有更大优势,且差异具有统计学意义。受纳入文献数量和质量的限制,Meta分析结果尚有待与高质量的大样本随机对照试验予以证实。     

自体髂骨再造桡骨头维持肘关节稳定的实验研究

目的利用兔动物模型进行实验研究,评价桡骨小头切除后用自体髂骨与尺骨冠突桡侧面融合再造桡骨头的骨愈合效果。方法选用健康成年新西兰白兔24只,随机分为实验组和对照组,每组各12只。实验组切除单侧桡骨头颈,取自体髂骨块行桡骨头再造。对照组在麻醉后行传统单侧桡骨小头切除术。2组在术后第4、8、12周分别处死4只白兔,通过大体标本测量肘关节外翻角的变化,进行影像学和骨组织形态计量分析观察骨愈合的效果。结果 2组肘关节外翻角随观察时间延长而逐渐增加,对照组增加幅度相对较大,而实验组增加幅度相对更小。大体标本肘关节外翻角测量(肘伸直位):术后12周时,对照组桡骨小头切除侧为(19.6±2.8)°,实验组桡骨头切除重建侧为(5.6±1.8)°,组间差异有统计学意义(t=4.004,P=0.028)。对照组术后均未见明显骨痂形成,实验组术后8周骨痂面积X线评分显著高于术后4周(t=5.175,P=0.014),术后12周显著高于术后8周(t=8.891,P=0.003)。实验组术后4周骨融合面部分软骨痂形成,术后8周再造骨融合面有较多骨痂形成,骨板排列无规律,术后12周再造骨融合面有大量新生骨痂形成;对照组桡骨小头切除后缺损处仅为纤维组织填充。结论改良桡骨头切除自体髂骨再造重建手术治疗Mason Ⅲ型桡骨小头骨折安全可行,自体髂骨块再造桡骨头能与尺骨冠突桡侧面牢固愈合,术后稳定性及融合效果良好。