Fluorinated poly(propylenimine) dendrimers as gene vectors

The use of poly(propylenimine) (PPI) dendrimers as gene delivery vectors is limited by their low transfection efficacy and serious cytotoxicity. In this study, we prepare a series of efficient and low cytotoxic gene vectors based on PPI dendrimers using a facile fluorination strategy. Fluorinated G3, G4, and G5 PPI dendrimers show comparable or superior transfection efficacies to six representative transfection reagents such as Lipofectamine 2000, jetPEI, branched poly(ethyleneimine), SuperFect, PolyFect, as well as arginine-modified dendrimer on both HEK293 and HeLa cells. These fluorinated PPI dendrimers exhibit low cytotoxicity on the transfected cells because they achieve optimal transfection efficacy at extremely low nitrogen to phosphorus (N/P) ratios. In addition, the synthesized materials show high transfection efficacy on 3D multicellular spheroids. These results demonstrate that fluorination is a promising strategy to improve the transfection efficacy of PPI dendrimers while reducing the cytotoxicity of these cationic polymers.     

上颈椎合并远隔颈椎骨折脱位一期前后路手术的评价

目的：通过一期前后路手术来评价该方法治疗上颈椎合并远隔颈椎骨折脱位的可行性与安全性。方法：对1996年5月至2000年6月入院的10例上颈椎与远隔颈椎同时存在骨折脱位的患者进行一期前后路联合手术,其中男性8例,女性2例,年龄从30－68岁不等。下颈椎骨折和／或脱位主要采用前路手术,包括椎体次全切或单椎间隙椎间盘切除,髂骨块移植,带锁钢板内固定。上颈椎骨折脱位主要采用后路手术,利用Apofix系统、Atlas线览系统或Axis系统进行复位植骨固定。所有患者术后均给予颈托保护;对同时伴有脊髓损伤者,尤其是累及C4以上水平,呼吸受累者,可行预防性气管切开术。术后均行重症监护,术后平均随访2年5个月。结果：10例患者均获得满意的复位固定,植骨区域均获得骨性融合,无神经损伤加重,植骨块移位或钢板螺钉松动断裂等并发症。结论：一期前后路联合手术复位,减压、植骨和内固定,重建上颈椎合并远隔颈椎骨折脱位后的稳定性,可提供即刻的坚强固定,避免术后Halo支架或颅骨牵引,便于术后护理和尽早开始功能锻炼,是一种理想的选择。     

Protein intake and physical function in older adults: A systematic review and meta-analysis

BackgroundThe present study explored cross-sectional and longitudinal associations between protein intake and physical function in older adults.MethodsWe conducted a systematic review and meta-analysis of cross-sectional and longitudinal studies that investigated the association between protein intake and measures of physical function in older adults. Cross-sectional, case-control, and longitudinal cohort studies that investigated the association between protein intake and physical function as a primary or secondary outcome in people aged 60 + years were included. Studies published in languages other than English, Italian, Portuguese, or Spanish were excluded. Studies were retrieved from MEDLINE, SCOPUS, EMBASE, CINAHL, AgeLine, and Food Science Source databases through January 31, 2022. A pooled effect size was calculated based on standard mean differences (SMD), MD, log odds ratio (OR) and Z-score..ResultsTwenty-two cross-sectional studies examined a total of 11,332 community-dwellers, hospitalized older adults, and elite senior athletes with a mean age of approximately 75 years. The pooled analysis indicated that a protein intake higher than the recommended dietary allowance (RDA) was significantly associated with higher Short Physical Performance Battery (SPPB) scores (SMD: 0.63, 95% CI: 0.27, 0.99, P-value: 0.0006), faster walking speed, greater lower-limb (SMD: 0.22, 95% CI: 0.04, 0.40, P-value: 0.02) and isometric handgrip strength (Z-score: 0.087, 95% CI: 0.046–0.128, P-value: 0.0001), and better balance (SMD: 0.33, 95% CI: 0.05, 0.62, P-value: 0.02). Nine longitudinal studies investigated 12,424 community-dwelling and native older adults with a mean age of approximately 85 years. A protein intake higher than the current RDA was not associated with lower decline in either isometric handgrip strength (logOR: 0.99, 95% CI: 0.97–1.02, P-value= 0.67) or walking speed (logOR: 0.92, 95% CI: 0.77–1.10, P-value= 0.35).ConclusionsA protein intake higher than the RDA is cross-sectionally associated with better physical performance and greater muscle strength in older adults. However, a high consumption of proteins does not seem to prevent physical function decline over time.     

Animal models for studying the etiology and treatment of low back pain

Chronic low back pain is a major cause of disability and health care costs. Effective treatments are inadequate for many patients. Animal models are essential to further understanding of the pain mechanism and testing potential therapies. Currently, a number of preclinical models have been developed attempting to mimic aspects of clinical conditions that contribute to low back pain (LBP). This review focused on describing these animal models and the main behavioral tests for assessing pain in each model. Animal models of LBP can be divided into the following five categories: Discogenic LBP, radicular back pain, facet joint osteoarthritis back pain, muscle‐induced LBP, and spontaneous occurring LBP models. These models are important not only for enhancing our knowledge of how LBP is generated, but also for the development of novel therapeutic regimens to treat LBP in patients. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1305–1312, 2018.

     

Reconstruction of reflex pathways to the atonic bladder after conus medullaris injury: preliminary clinical results

Neurogenic bladder dysfunction following spinal cord injury is a major medical and social problem for which there is no ideal treatment strategy. In this study, spinal root anastomoses were performed in 10 paraplegic patients with traumatic lesions of the conus medullaris, in an attempt to reinnervate the paralyzed bladder. For the operation, the functional T11 ventral root (VR) above the lesion was transected and anastomosed to the S2 ventral roots unilaterally through a nerve graft. The T11 dorsal root was left intact as the trigger for micturition after axonal regeneration. All patients underwent urodynamic evaluation before surgery and at follow-up. The mean follow-up duration was 2 years. Of the 10 patients, 7 (70%) regained satisfactory bladder control within 18-24 months after VR microanastomosis. In these seven patients, the average bladder capacity decreased from 508 +/- 83 (mean +/- SD) to 370 +/- 59 ml, residual urine decreased from 477 +/- 98 to 35 +/- 11 ml, and urinary infections were not observed. Patients with impaired renal function experienced a full recovery. Three patients failed to show any improvement after the operation. These results suggest that a restitutive process occurs in the bladder following reinnervation from new T11 VR connections to the bladder nerves. Spinal cord lesions that may benefit from such a nerve crossover surgery are those located at the conus, whereby a functional suprasacral nerve can be connected to the sacral roots to bypass the injury in an attempt to restore central connections to the bladder.     

Bypassing spinal cord injury: surgical reconstruction of afferent and efferent pathways to the urinary bladder after conus medullaris injury in a rat model

Afferent and efferent nerve function in the atonic bladder caused by conus medullaris injury in a rat model was established by intradural microanastomosis of the left L5 ventral root (VR) to right S2 VR to restore pure motor-to-motor reinnervation coupled with extradural postganglionic spinal nerve transfer of L5 dorsal root (DR) to S2 DR for pure sensory-to-sensory reinnervation. Early function of the reflex arc was evaluated by electrophysiological study, as well as by intravesicular pressure measurement and histological examination. The results demonstrated that single focal stimulation of the left S2 DR elicited evoked potentials at the left vesicular plexus before and after horizontal spinal cord damage between the L6 and S4 level. Bladder contraction was successfully initiated by trains of stimuli targeting the left L5-S2 DR anastomosis. Achievable bladder pressures and amplitude of bladder smooth muscle complex action potentials were unchanged before and after induced paraplegia and comparable to those of the control. Prominent axonal sprouting was seen in the distal part of nerve graft. Both afferent and efferent nerve pathways in the atonic bladder can be reconstructed by suprasacral motor-to-motor and sensory-to-sensory nerve transfer after spinal cord injury in rats. This reconstructive strategy has significant potential in clinical application.     

齿突游离小骨的影像学测量与手术治疗

目的对齿突游离小骨的影像学测量及其手术治疗进行研究.方法对已治疗的45例齿突游离小骨进行分析,其中38例采用3种影像学测量方法来评价C1～2不稳程度.所有病人均行后路融合术,其中寰枢椎融合28例,枕颈融合17例.结果测量分析发现,上颈椎最大椎管矢状径<13mm时有脊髓损害的危险.所有手术病人平均随访6年,均取得牢固骨性愈合.38例临床症状改善,4例无变化,3例加重.结论对于齿突游离小骨伴有脊髓压迫症状,或仅有枕颈部症状但影像学测量椎管矢状径减小接近13mm这一临界值,有脊髓损害危险时应施行手术治疗.     

脊髓半切伤后胶质纤维酸性蛋白的表达及意义

目的:研究脊髓半切伤(hSCI)后脊髓远端组织星形胶质细胞中胶质纤维酸性蛋白(GFAP)表达的意义,并探讨反应性胶质化在脊髓半切伤中的作用。方法:SD大鼠25只,随机分为5组(n=5),正常对照组、脊髓半切伤后1d、4d、7d和14d组。用免疫组化及图像分析方法观察星形胶质细胞中GFAP的表达;用大鼠综合行为评分(CBS)对各组评分。结果:hSCI后远端星形胶质细胞GFAP表达比对照组明显增高(P<0.01);1～14d呈进行性增高,损伤各组CBS1～14d呈降低趋势,两指标有显著性相关性(r=-0.05,P<0.01)。结论:hSCI后星形胶质细胞通过其反应性胶质化对脊髓再生和修复起重要作用。     

几丁聚糖和透明质酸钠抑菌作用的研究

目的　比较几丁聚糖和透明质酸钠的抑菌作用及抑菌范围。方法　对奇异变形杆菌、大肠埃希氏菌、白色念珠菌、铜绿假单胞菌及金黄色葡萄球菌进行培养。每种细菌培养 33管 ,其中 30管分为 A、B及 C组 ,按倍比稀释法在 A组加入高相对分子量 (Mr)几丁聚糖 ,B组加入低 Mr几丁聚糖 ,C组加入透明质酸钠 ;另 3管为对照组 (D组 )。37℃恒温下培养 18小时 ,观察细菌的生长情况。结果　 A组最小抑菌浓度 (MIC)为 :奇异变形杆菌 0 .0 31% ,大肠埃希氏菌 0 .0 6 3% ,白色念珠菌 0 .0 6 3% ,铜绿假单胞菌 0 .0 6 3% ,金黄色葡萄球菌 0 .0 6 3% ;B组 MIC为 :奇异变形杆菌0 .12 5 % ,大肠埃希氏菌 0 .2 5 % ,白色念珠菌 0 .2 5 % ,铜绿假单胞菌 0 .2 5 % ,金黄色葡萄球菌 0 .12 5 %。 C组和 D组各管都有细菌生长。结论　透明质酸钠无抑菌作用 ;几丁聚糖有广谱抑菌作用 ,而高相对分子量几丁聚糖抑菌能力较强。