胸腰椎爆裂性骨折短节段伤椎固定三维有限元模型构建及生物力学比较研究

[目的]建立胸腰椎爆裂性骨折后路不同固定方式的尸体标本和三维有限元模型,比较不同固定方式的生物力学特点,优化手术方式选择。[方法]6具20~40岁青壮年胸腰椎(T11~L3)标本,压缩法制作L1椎体爆裂性骨折模型。平均分成3组,分别行后路长节段固定、常规短节段固定和伤椎短节段固定的手术固定方式,三维运动试验机检测标本在10 N·m力矩下前屈、后伸、侧屈和旋转4个方位的运动范围(ROM),材料机评估标本在500 N压力下的轴向压缩刚度。另取1具尸体为正常胸腰椎模型,借助CT扫描和有限元软件,模拟L1节段爆裂性骨折生成三种不同手术固定方式的有限元模型,施加相应载荷,分析各模型的应力分布,比较并进一步验证力学分析结果。[结果]生物力学证明,后路长节段固定、短节段固定和伤椎短节段固定后的胸腰段爆裂性骨折模型的ROM值和轴向压缩刚度组间差异无统计学意义。三维有限元应力分布显示,常规短节段和经伤椎短节段固定在T12平面的应力显著小于后路长节段固定方式。[结论]三种手术固定方式均能达到T11~L3节段的稳定,但后路常规短节段固定和经伤椎短节段固定更易于对伤椎的保护,经伤椎短节段固定具有更高的稳定性。     

The Morphology and Electrophysiology of the Cochlea of the Miniature Pig

To report the cochlear morphology and electrophysiology of Chinese experimental miniature pigs. Twenty Chinese experimental miniature pigs were used in this study. Auditory brainstem responses (ABR), cochlear endolymphatic potentials (EP), and the potassium concentrations of cochlear endolymph were recorded. Hair cell morphology was examined using electron microscopy. The capsule of cochlea of the miniature pig has three and one‐half turns which contains a 39‐mm long membranous labyrinth. The organ of Corti in the labyrinth encompasses three rows of outer hair cells and one row of inner hair cells. The stereocilia of the hair cells in the apical turn of the cochlea were significantly longer than those in the basal turn. The vestibular apparatus consists of three semicircular canals and the otolith organs. The average threshold of the ABR was 35–45 dB SPL (n = 20) from 4 to 32 kHz. There was no significant difference in the threshold or latency of the ABR between 1‐day‐old and 30‐day‐old miniature pigs. The average EP value was 77.3 ± 14 mV (n = 9) and the average potassium concentration was 147.1 ± 13 mM (n = 5) recorded from the second turn of the cochlea. These studies on the cochlear morphology and electrophysiology of the miniature pigs help to establish the Chinese experimental miniature pig as an animal model for future studies in otology and audiology. Anat Rec, 298:494–500, 2015. © 2014 Wiley Periodicals, Inc.     

The auditory novelty system: An attempt to integrate human and animal research

In this account, we attempt to integrate two parallel, but thus far, separate lines of research on auditory novelty detection: (1) human studies of EEG recordings of the mismatch negativity (MMN), and (2) animal studies of single‐neuron recordings of stimulus‐specific adaptation (SSA). The studies demonstrating the existence of novelty neurons showing SSA at different levels along the auditory pathway's hierarchy, together with the recent results showing human auditory‐evoked potential correlates of deviance detection at very short latencies, that is, at 20–40 ms from change onset, support the view that novelty detection is a key principle that governs the functional organization of the auditory system. Furthermore, the generation of the MMN recorded from the human scalp seems to involve a cascade of neuronal processing that occurs at different successive levels of the auditory system's hierarchy.     

Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction

Manganese (Mn) oxides are among the most reactive minerals within the environment, where they control the bioavailability of carbon, nutrients, and numerous metals. Although the ability of microorganisms to oxidize Mn(II) to Mn(III/IV) oxides is scattered throughout the bacterial and fungal domains of life, the mechanism and physiological basis for Mn(II) oxidation remains an enigma. Here, we use a combination of compound-specific chemical assays, microspectroscopy, and electron microscopy to show that a common Ascomycete filamentous fungus, Stilbella aciculosa, oxidizes Mn(II) to Mn oxides by producing extracellular superoxide during cell differentiation. The reactive Mn oxide phase birnessite and the reactive oxygen species superoxide and hydrogen peroxide are colocalized at the base of asexual reproductive structures. Mn oxide formation is not observed in the presence of superoxide scavengers (e.g., Cu) and inhibitors of NADPH oxidases (e.g., diphenylene iodonium chloride), enzymes responsible for superoxide production and cell differentiation in fungi. Considering the recent identification of Mn(II) oxidation by NADH oxidase-based superoxide production by a common marine bacterium (Roseobacter sp.), these results introduce a surprising homology between some prokaryotic and eukaryotic organisms in the mechanisms responsible for Mn(II) oxidation, where oxidation appears to be a side reaction of extracellular superoxide production. Given the versatility of superoxide as a redox reactant and the widespread ability of fungi to produce superoxide, this microbial extracellular superoxide production may play a central role in the cycling and bioavailability of metals (e.g., Hg, Fe, Mn) and carbon in natural systems.     

不同入路减压内固定治疗胸腰椎爆裂骨折

目的 探讨不同入路减压内固定治疗胸腰椎爆裂骨折的疗效.方法 将92例胸腰锥爆裂性骨折患者根据病情和患者知情同意分为两组：后路短节段椎弓根螺钉内固定融合术47例,前路减压钛网植骨内固定术45例.对两种治疗方式的疗效进行比较.结果 两组均获满1年随访.两组患者的神经功能均好转;两组患者治疗1年后较治疗前的椎体前缘高度、Cobb角均有明显改善（P〈0.05）;治疗后两组间椎体前缘高度、Cobb角比较差异无统计学意义（P〉0.05）;两组均无顽固性腰痛及内固定断裂等并发症发生.结论 后路短节段椎弓根螺钉内固定融合术和前路减压钛网植骨内固定术治疗胸腰椎爆裂骨折均可取得较好效果.     

Effect of Bioactive Polypeptides on Leaking Large Bowel Anastomosis and Intestines in the Rat

Anastomotic leakage and postoperative adhesions represent major complications after colorectal surgery. We have previously shown a positive effect on both anastomotic strength and abdominal adhesions by the use of differently charged bioactive polypeptides. The present study aimed to investigate the effect of the same polypeptides on the healing of an insufficient intestinal anastomosis, as well as on accidental intestinal injury, in addition to measuring the preventive effect against the development of abdominal adhesions. An insufficient, and thereby potentially leaking, intestinal anastomosis and punctures of the intestine (“accidental intestinal injury model”) were performed in rats. The treatment groups received intraperitoneal administration of poly-L-lysine and poly-L-glutamate, while controls received sodium chloride. Burst pressure, extent of abdominal adhesions, and postoperative complications were analyzed in both experimental models. A significant decrease of adhesions was seen in all animals treated with polypeptides (p <. 05). Burst pressure was significantly higher (p <. 001) in animals with intestinal perforation as seen on day 1 and then decreasing. A significant decrease in the incidence of peritonitis was also noted early (day 1) in this model (p =. 002). The mortality and complications were high in the intestinal anastomosis model, though not affected by treatment with polypeptides. Intraabdominal adhesions were significantly reduced using polypeptides in this study, with no observed effect on other postsurgical complications. There were signs of less infectious complications in polypeptide treated animals. In animals with accidental intestinal injury, a higher burst pressure was noted in treated animals.     

经皮椎体成形术及后凸成形术在胸腰椎骨质疏松性爆裂骨折中的应用现状

经皮椎体成形术（percutaneous vertebroplasty,PVP）及后凸成形术（percutaneous kyphoplasty,PKP）目前广泛地应用于骨质疏松压缩性脊柱骨折中,但对于骨折累及椎管、椎体后壁有破裂甚至占位的爆裂性骨折,该技术曾一度被视为绝对手术禁忌。而中老年患者常发生骨质疏松性椎体爆裂骨折（osteoporotic vertebral burst fractures,OVBF）。他们是否如同骨质疏松性压缩性骨折（osteoporotic vertebral compression fractures,OVCF）患者那样从PVP和PKP手术中获益这个问题,促使越来越多的国内外学者开始研究、探讨,希望评价该技术在OVBF患者中的风险与受益。本文主要综述近十多年来该技术在OVBF中应用的疗效和安全性。