Evaluation of high protein intake to improve clinical outcome and nutritional status for patients with burns: a systematic review

Background and aimPatients with severe burns undergo a local and systemic response to the injury. As part of this response the patient becomes hypermetabolic. Current guidelines advise high protein intakes to counteract the catabolic response to burns, but this appears to be based on minimal experimental evidence. Hence the aim of this review was to examine the evidence for improvements in nutritional status and clinical outcome with the administration of high protein intakes for patients with burns.MethodsEight databases were searched for clinical trials with burn patients receiving two or more levels of protein intake at or above the level recommended for healthy individuals (0.75 g/kg/d) and presenting results for at least one of the following pre-defined outcomes: nitrogen balance, length of stay, weight change, survival, physical therapy index, protein fractional synthetic rate, immunological measurements, bacteraemic days, systemic antibiotic days and net protein synthesis.ResultsSix studies were included, 4 of which were randomized trials. All had major methodological limitations, in particular none was blinded. There was too much heterogeneity in study design, patient characteristics and the timing and magnitude of the interventions to justify formal meta-analysis. There was no reliable evidence of improvement in nitrogen balance, but there was some evidence of increased weight gain on higher protein diets. One small study reported an increase in survival and significant improvements in infection rates and some indicators of immune function in children. Length of stay was not significantly improved. There was weak evidence of an improvement in muscle strength and endurance but no significant increase in protein synthesis in muscle or skin, or net protein synthesis in the whole body.ConclusionThere is currently only very weak evidence to justify administering high protein diets to patients following burns.     

Establishment of a bilateral femoral large segmental bone defect mouse model potentially applicable to basic research in bone tissue engineering

Background

To understand the cellular mechanism underlying bone defect healing in the context of tissue engineering, a reliable, reproducible, and standardized load-bearing large segmental bone defect model in small animals is indispensable. The aim of this study was to establish and evaluate a bilateral femoral defect model in mice.

Materials and methods

Donor mouse bone marrow mesenchymal stem cells (mBMSCs) were obtained from six mice (FVB/N) and incorporated into partially demineralized bone matrix scaffolds to construct tissue-engineered bones. In total, 36 GFP⁺ mice were used for modeling. Titanium fixation plates with locking steel wires were attached to the femurs for stabilization, and 2-mm–long segmental bone defects were created in the bilateral femoral midshafts. The defects in the left and right femurs were transplanted with tissue-engineered bones and control scaffolds, respectively. The healing process was monitored by x-ray radiography, microcomputed tomography, and histology. The capacity of the transplanted mBMSCs to recruit host CD31⁺ cells was investigated by immunofluorescence and real-time polymerase chain reaction.

Results

Postoperatively, no complication was observed, except that two mice died of unknown causes. Stable fixation of femurs and implants with full load bearing was achieved in all animals. The process of bone defect repair was significantly accelerated due to the introduction of mBMSCs. Moreover, the transplanted mBMSCs attracted more host CD31⁺ endothelial progenitors into the grafts.

Conclusions

The present study established a feasible, reproducible, and clinically relevant bilateral femoral large segmental bone defect mouse model. This model is potentially suitable for basic research in the field of bone tissue engineering.     

冻干同种异体髂骨作为支架材料的性能研究

目的 研究冻干同种异体髂骨块支架材料的微观结构及生物力学特点.方法 参考美国组织库协会标准,进行髂骨块采取、脱细胞、脱脂、脱蛋白、消毒、保存.分别将纤维蛋白胶、利福平负压灌注入骨块孔隙内;大体观察冻干同种异体髂骨块、载利福平髂骨块的结构特征,扫描电镜观察孔径、孔隙连通、利福平晶体分布情况,液体置换法测定孔隙率和密度,弯曲试验、扭转试验、压缩试验评价其力学性能.结果 冻干同种异体髂骨支架材料呈乳白色,为三面薄层皮质骨及中间松质骨组成的"夹心饼结构",具有骨组织天然三维网状孔隙,孔隙内洁净,相互连通,利福平晶体被纤维蛋白胶均匀地固定于骨块表面和内部;冻干同种异体髂骨块密度(0.35±0.03)g/ml,孔隙率(67.23±9.12)%,孔径(395.36±37.02)μm,抗扭强度(5.96±1.53)MPa,抗压强度(9.94±0.73)MPa,弹性模量(376.14±27.32)MPa,抗弯强度(15.70±2.35)MPa.结论 冻干髂骨块具有天然生理性孔隙,生物力学性能良好,具有广阔的开发前景.     

Nano-hydroxyapatite modulates osteoblast lineage commitment by stimulation of DNA methylation and regulation of gene expression

Hydroxyapatite (HA) is the primary structural component of the skeleton and dentition. Under biological conditions, HA does not occur spontaneously and therefore must be actively synthesized by mineralizing cells such as osteoblasts. The mechanism(s) by which HA is actively synthesized by cells and deposited to create a mineralized matrix are not fully understood and the consequences of mineralization on cell function are even less well understood. HA can be chemically synthesized (HAp) and is therefore currently being investigated as a promising therapeutic biomaterial for use as a functional scaffold and implant coating for skeletal repair and dental applications. Here we investigated the biological effects of nano-HAp (10 × 100 nm) on the lineage commitment and differentiation of bone forming osteoblasts. Exposure of early stage differentiating osteoblasts resulted in dramatic and sustained changes in gene expression, both increased and decreased, whereas later stage osteoblasts were much less responsive. Analysis of the promoter region one of the most responsive genes, alkaline phosphatase, identified the stimulation of DNA methylation following cell exposure to nano-HAp. Collectively, the results reveal the novel epigenetic regulation of cell function by nano-HAp which has significant implication on lineage determination as well as identifying a novel potential therapeutic use of nanomaterials.     

Immunohistochemical localization of steroid receptor coactivators in chondrosarcoma: An in vivo tissue microarray study

Chondrosarcoma is the second most common type of primary bone malignancy following up osteosarcoma, characterized by resistance to conventional chemotherapeutic agents and radiation regimens. The p160 family members steroid receptor coactivator-1 and -3 (SRC-1 and SRC-3) have been implied in the regulation of cancer growth, migration, invasion, metastasis and chemotherapeutic resistance; but we still lack detailed information about the levels of SRCs in chondrosarcoma. In this study, expression of SRC-1 and SRC-3 in chondrosarcoma was examined by immunohistochemistry with tissue microarrays; the four score system (0, 1, 2 and 3) was used to evaluate the staining. The results showed that there were no gender-, site- or age-differences regarding the expression of SRC-1 or SRC-3 (p > 0.05); organ (bone or cartilage) -differences were only detected for SRC-1 but not SRC-3 (p < 0.05). Significant higher levels of SRC-1 and SRC-3 were detected in MDC and PDC when compared to WDC. Our study clearly demonstrated differentiation-dependant expression of SRC-1 and SRC-3 in chondrosarcoma, may be novel targets for the prognosis and/or treatment of chondrosarcoma, would have opened a new avenue and established foundation for studying chondrosarcoma.     

前路减压植骨融合及钛板固定治疗胸腰椎骨折合并脊髓损伤

目的观察前路减压、植骨融合及钛板固定治疗胸腰椎骨折合并脊髓损伤的临床疗效。方法1999年3月～2004年5月有68例胸腰椎骨折合并脊髓损伤的患者接受前路减压、结构性植骨及钛板固定治疗。本组男45例，女23例，年龄14～61岁，平均36．7岁。骨折节段：T11 1例、T12 20例、L1 33例、L2 12例，为L1．2 1例和L2．3 1例。神经功能情况：完全性截瘫10例，不全性截瘫58例。固定器材：Z-PLATE钛板43例，PROFILE钛板19例，ALPS钛板6例。植骨材料：自体髂骨块45例和充填自体碎骨的钛网23例。采用Frankel分级和ASIA评分评估神经功能恢复情况，通过影像学检查脊柱畸形角(Cobb角)的纠正、减压范围、骨块或钛网的位置及骨愈合情况。结果65例随访8～48个月(3例失访)，平均15．6个月。61例术后神经功能均有不同程度的改善，平均提高了1．25级，ASIA评分明显提高。Cr及M砒检查示椎管减压彻底。髂骨块和钛网均无松动、移位等变化。三种钛板均无松动、移位及断裂。所有随访病例脊柱畸形均获得良好矫正和骨性融合，无畸形矫正的丢失。结论胸腰椎骨折合并脊髓损伤行前路减压安全彻底，有利于神经功能恢复。钛板内固定和结构性植骨稳定性好，骨性愈合率高。     

副舟骨源性平足症的手术治疗策略

副舟骨源性平足症是临床常见的足部畸形之一,目前其治疗方法存在较多争议,不同手术方法临床疗效差异较大,针对副舟骨源性平足症的外科治疗尚无统一标准,围绕副舟骨切除后如何重塑足弓产生了一系列手术方法,不同术式产生的临床疗效亦不尽相同,如何制定手术策略,选择手术方式,以及副舟骨切除后是否需要重建胫后肌腱,如何重建,采用何种方式重建等问题是目前研究的热点和难点,期待更进一步的研究。     

Endometrial Ablation: Long-Term Outcome

hysteroscopic endometrial ablation is an effective treatment for the management of chronic menorrhagia unresponsive to medical therapy, with acceptably low complication rates and high patient satisfaction rates when assessed at long term follow-up. Endometrial ablation compares favourably with hysterectomy in randomized trials comparing efficacy and cost. Global endometrial ablation devices are currently being evaluated and may Prove useful alternatives to hysteroscopis endometrial ablation surgery in selected patients. Good patient selection may optimize outcome with hysteroscopis endometrial ablation surgery. Endometrial pretreatment does not improve long term outcome. Further studies of long term follow-up are necessary to assess the efficacy of this procedure.     

一期前方入路病灶清除植骨融合内固定治疗下颈椎结核

目的探讨一期前方入路结核病灶清除髂骨移植内固定治疗下颈椎结核的疗效。方法本组均采用一期前方入路行病灶清除、植骨融合和内固定术。结果术中无大血管、脊髓或喉返神经损伤,术后随访所有患者结核症状消失,无结核复发、切口感染、窦道形成或内固定失败等并发症,复查血沉结果正常。结论一期前方入路显露下颈椎结核病灶安全可靠,椎管减压效果显著,病灶清除后行自体或同种异体髂骨植骨,钢板内固定可有效重建颈椎的稳定性。     

The biomechanics of point contact-dynamic compression plate and its effects on bone perfusion

Objective: To compare the mechanical properties of point contact-dynamic compression plate (PC-DCP) and its effects on cortical bone perfusion with that of dynamic compression plates (DCP) in goat tibiae. Methods: Twenty pairs of matched fresh goat tibiae were used. A transverse fracture model was established. The fractures with a 3mm interspace between the fracture ends were subject to fixations with the DCPs and the PC-DCPs respectively, then the four-points bending tests and the torsion tests were conducted to compare the mechanical properties of the PC-DCP with that of DCP. Another 13 sexually mature goats underwent fixations with the DCPs and the PC-DCPs, respectively, at the mid-shafts of the intact bilateral tibiae. Ischemic zones were observed at four time points (1 day ,2,6, and 12 weeks after operation) using disulphine blue staining technique. Results: There were no significant differences in mechanical properties, such as bend- and torsion-resistance, between the DCPs and the PC-DCPs. One day, 2, and 6 weeks after operation, on the side of DCP fixation, outer cortical bone ischemia under the plate persisted, and this condition did not reverse until 12 weeks after operation. However, on the side of PC-DCP fixation, cortical bone ischemia occurred only in the periphery of the screw holes and at the contact sites of the PC NUTs 1 day after operation, and it disappeared at 2 weeks after operation. Conclusions: The PC-DCP has similar biomechanical properties of the DCP, byt is less detrimental to local bone blood circulation than the conventional plates.