Role of sodium channels in recovery of sciatic nerve‐stretch injury in rats

Introduction: To elucidate the mechanism of functional recovery after gradual nerve‐stretch injury, we used rats in which the femur length was increased by 15 mm at 1.5 mm/day. Methods: We performed electrophysiology, mRNA analysis of tetrodotoxin‐resistant voltage‐gated sodium channels (TTX‐R VGSCs) in dorsal root ganglia, and histology of unmyelinated sciatic nerve fibers and examined pain thresholds at 1, 10, 20, and 30 days after cessation of lengthening. Results: Electrophysiology revealed conduction block after cessation that recovered after 30 days. TTX‐R VGSC levels decreased immediately after cessation but were restored after 10 (Nav1.9) or 20 (Nav1.8) days. Histology revealed that injured unmyelinated nerve fibers regenerate 30 days after cessation. Pain threshold decreased gradually during lengthening but had not recovered to the control group level after 30 days. Conclusions: Early restoration of TTX‐R VGSC mRNA in dorsal root ganglia preceded functional recovery of stretched nerves before regeneration of injured unmyelinated nerve fibers. Muscle Nerve 50 : 425–430, 2014     

抗结核药物复合支架的制备及其性能研究

【摘要】 目的：制备抗结核药物复合支架,并观察其载药性能、药物释放性能和组织相容性。方法：应用乳酸-羟基乙酸共聚物（PLGA）、磷酸三钙（β-TCP）、异烟肼（INH）,通过结合相分离/粒子沥滤法制备成复合药物支架。采用扫描电镜观察支架的形貌;测定支架的孔隙率;在体外测定支架的生物力学强度、载药率、包封率以及药物释放特性;将复合支架（PLGA/β-TCP/INH）埋入大鼠肌肉中,4周后取材固定、染色行组织切片观察其组织相容性。结果：PLGA/β-TCP/INH复合支架表面及内部呈均匀多孔状,孔隙分布较均匀,在大孔的周围布满了相互贯通的微孔,外形多为近似圆形,大孔直径约150~300μm,平均222±23μm,小孔直径约10μm;孔隙率为（86±3）%;抗压强度为1.93±0.65MPa,药物包封率为（66.73±2.65）%;在体外药物释放过程较平稳,其释放曲线较平滑;组织学检查显示埋入大鼠肌肉中4周支架周围组织正常,细胞无变性坏死。结论：PLGA/β-TCP/INH复合支架具有良好的孔隙率、力学强度、释药特性和组织相容性,有望在脊柱结核病灶清除术后利用其修复骨缺损的同时发挥局部抗结核治疗作用。     

孟鲁司特钠治疗小儿变异性哮喘的临床疗效探讨

目的：探讨孟鲁司特钠治疗小儿变异性哮喘的临床疗效。方法选取我院2011年4月～2014年1月收治的180例小儿变异性哮喘患者作为研究对象,随机分为实验组和对照组各90例,对照组患者仅给予常规对症治疗,实验组患者在常规治疗的基础上加用孟鲁斯特钠治疗,比较两组患者临床治疗效果、各项症状缓解时间以及肺功能改善情况。结果实验组患者临床治疗效果总有效率显著优于对照组（P＜0.05）。实验组患者咳嗽消失时间、哮鸣音消失时间以及哮喘持续时间均明显短于对照组患者,两组间比较差异有统计学意义（P＜0.05）。治疗后两组患者FEV1和PEF（%）均较治疗前得到一定改善,差异有统计学意义（P＜0.05）,其中实验组患者改善较明显,与对照组比较差异有统计学意义（P＜0.05）。对照组患者不良反应发生率显著高于实验组患者,差异有统计学意义（x2=4.185,P＜0.05）。结论小儿变异性哮喘应用孟鲁斯特钠治疗可以有效改善肺部功能,迅速缓解临床症状,同时其安全性较高,值得在临床治疗中推广应用。     

The effects of non-calcium-based phosphate binders versus calcium-based phosphate binders on cardiovascular calcification and bone remodeling among dialysis patients: a meta-analysis of randomized trials

Background: Vascular calcification significantly increases the rates of cardiovascular mortality in hemodialysis (HD) patients. Abnormalities in mineral metabolism may play a role in the pathogenesis of arterial calcification. Whether patients treated with non-calcium-based phosphate binders had reduced aortic vascular calcification compared to those treated with calcium-based phosphate binders is still unclear. Methods: We searched multiple databases for studies published through August 2013 that evaluated the effects of non-calcium-based phosphate binders (NCBP) versus calcium-based phosphate binders (CBP) on cardiovascular calcification and bone remodeling among dialysis patients. We summarized test performance characteristics with the use of forest plots, fixed and random effects models, and Egger regression test. Results: Eighteen eligible randomized controlled trials totaling 3676 patients were included. Meta-analysis results showed NCBP could significantly attenuate the progression of coronary artery calcification than CBP (WMD: ?144.62, 95% CI: ?285.62 to ?3.63). The serum calcium levels significant lower in NCPB group than in CPB groups (WMD: ?0.26, 95% CI: ?0.37 to ?0.14), but the serum iPTH levels were significantly higher in NCPB groups (WMD: 57.1, 95% CI: 13.42 to 100.78). The osteoid volume and osteoblast numbers were significant higher in NCPB group than in CPB group (WMD: 1.75, 95% CI: 0.78 to 2.73 for osteoid volume; WMD: 4.49, 95% CI: 1.83 to 7.15 for osteoblast numbers). The Egger regression test also showed no potential publication bias (p?=?0.725). Conclusions: Based on available data, NCBPs have equally effective with CBPs for serum phosphate control. But there was significantly lower incidence of coronary artery calcification and a significant higher bone formatting rate in NCBP groups than in CBP groups. So we recommend NCBPs as phosphate binders for HD patients.     

Long‐term outcomes in African American kidney transplant recipients under contemporary immunosuppression: a four‐yr analysis of the Mycophenolic acid Observational REnal transplant (MORE) study

Mycophenolic acid Observational REnal transplant (MORE) was a prospective, observational study of de novo kidney transplant patients receiving mycophenolic acid (MPA). Four‐yr data on 904 patients receiving tacrolimus and enteric‐coated mycophenolate sodium (EC‐MPS) or mycophenolate mofetil (MMF) were analyzed to evaluate immunosuppression and graft outcomes in African American (AA, n = 218) vs. non‐AA (n = 686) patients. Mean tacrolimus dose was higher in AA vs. non‐AA patients but mean tacrolimus trough concentration was similar. Use of the recommended MPA dose in AA patients decreased from 78.9% at baseline to 33.1% at year 3. More AA patients received the recommended MPA dose with EC‐MPS than MMF at month 6 (56.2% vs. 35.7%, p = 0.016) and month 36 (46.6% vs. 16.7%, p = 0.029), with no safety penalty. Significantly, more AA patients received corticosteroids than non‐AA patients. Biopsy‐proven acute rejection was higher in AA vs. non‐AA patients (18.9% vs. 10.7%, p = 0.003), as was graft loss (10.9% vs. 4.4%, p = 0.003); differences were confirmed by Cox regression analysis. Patient survival was similar. Estimated GFR was comparable in AA vs. non‐AA patients. Kidney allograft survival remains lower for AA vs. non‐AA recipients even under the current standard of care.     

Summary of knowledge gaps related to quality and efficacy of current influenza vaccines

Influenza viruses are a public health threat, as they are pathogenic, highly transmissible and prone to genetic changes. For decades vaccination strategies have been based on trivalent inactivated vaccines, which are regulated by specific guidelines. The progress in scientific knowledge and the lessons learned from the A(H1N1)2009 pandemic have highlighted further the need to improve current guidelines, including the immunogenicity criteria set by the CHMP in 1997, and to promote the discussion on the shortcomings encountered, e.g. the evaluation of vaccine efficacy in the paediatric and elderly populations, the measurement of the naivety of a population, the impact of prior immunity on subsequent vaccinations, and the technical issues with the serological assays for detection of immunity and immunogenicity.     

Molecular Surface of JZTX-V (β-Theraphotoxin-Cj2a) Interacting with Voltage-Gated Sodium Channel Subtype NaV1.4

Voltage-gated sodium channels (VGSCs; Na_V1.1–Na_V1.9) have been proven to be critical in controlling the function of excitable cells, and human genetic evidence shows that aberrant function of these channels causes channelopathies, including epilepsy, arrhythmia, paralytic myotonia, and pain. The effects of peptide toxins, especially those isolated from spider venom, have shed light on the structure–function relationship of these channels. However, most of these toxins have not been analyzed in detail. In particular, the bioactive faces of these toxins have not been determined. Jingzhaotoxin (JZTX)-V (also known as β-theraphotoxin-Cj2a) is a 29-amino acid peptide toxin isolated from the venom of the spider Chilobrachys jingzhao. JZTX-V adopts an inhibitory cysteine knot (ICK) motif and has an inhibitory effect on voltage-gated sodium and potassium channels. Previous experiments have shown that JZTX-V has an inhibitory effect on TTX-S and TTX-R sodium currents on rat DRG cells with IC₅₀ values of 27.6 and 30.2 nM, respectively, and is able to shift the activation and inactivation curves to the depolarizing and the hyperpolarizing direction, respectively. Here, we show that JZTX-V has a much stronger inhibitory effect on Na_V1.4, the isoform of voltage-gated sodium channels predominantly expressed in skeletal muscle cells, with an IC₅₀ value of 5.12 nM, compared with IC₅₀ values of 61.7–2700 nM for other heterologously expressed Na_V1 subtypes. Furthermore, we investigated the bioactive surface of JZTX-V by alanine-scanning the effect of toxin on Na_V1.4 and demonstrate that the bioactive face of JZTX-V is composed of three hydrophobic (W5, M6, and W7) and two cationic (R20 and K22) residues. Our results establish that, consistent with previous assumptions, JZTX-V is a Janus-faced toxin which may be a useful tool for the further investigation of the structure and function of sodium channels.     

Intestinal necrosis related to administration of cation exchange resin without sorbitol: A retrospective analysis of 61 patients with end‐stage renal diseases

Intestinal necrosis associated with cation exchange resin (CER) is considered related to sorbitol, but it has been reported even in patients receiving CER alone. This study was performed to identify the risk factors of CER‐related intestinal necrosis. The pathological database of 61 end‐stage renal disease patients with surgical intervention for intestinal perforation was reviewed. The correlations between CER treatment and clinicopathological factors were studied among three groups: (i) patients administered CER and with CER at the perforation site (n = 23), (ii) patients administered CER with undetected CER at the perforation site (n = 12) and (iii) patients not administered CER (n = 26). The majority of the perforation site in group 1 was in the sigmoid colon (82.6%) with significantly higher average age and more frequent CER adhesion rates to the mucosa around the perforation site than group 2. The laxative administration rate in group 1 was significantly higher than group 3 and tended to be higher than group 2. The incidence of CER‐related intestinal necrosis was estimated at 0.57%. CER should be used with extreme caution in elderly patients with passage disturbance.     

伊班膦酸钠干预骨关节炎模型大鼠丝裂原活化蛋白激酶信号通路的变化

背景:丝裂原活化蛋白激酶信号通路参与成骨细胞与破骨细胞的分化,与软骨下骨重建过程密切相关,在骨关节炎的发生发展中起重要作用。双膦酸盐作为骨吸收抑制剂,主要用于骨质疏松的治疗。目的:探讨伊班膦酸钠对大鼠骨关节炎的治疗效果,以及其对丝裂原活化蛋白激酶信号通路的影响。方法:实验方案经南华大学附属第一医院动物实验伦理委员会批准。30只雌性SD大鼠随机分为假手术组、模型组、治疗组。模型组和治疗组行双侧去卵巢及前交叉韧带切断术,假手术组大鼠只切除卵巢周围与卵巢大小相仿的脂肪组织,切开双侧膝关节腔,但不切断前交叉韧带。术后1周,治疗组予以腹腔注射伊班膦酸钠10μg/kg,模型组予以腹腔注射等量生理盐水,假手术组不作干预。12周以后,处死实验动物,进行关节软骨的组织形态学观察及Mankin评分,软骨下骨的Micro-CT扫描及骨组织显微结构定量分析,检测丝裂原活化蛋白激酶信号通路中细胞外信号调节蛋白激酶(ERK1)和c-Jun氨基酸末端激酶(JNK)的mRNA表达量及蛋白表达水平。结果与结论:①模型组软骨结构明显破坏,Mankin评分较假手术组明显增高,而治疗组的Mankin评分较模型组显著降低(P<0.01);②与假手术组比较,模型组中的骨密度、骨体积分数、骨小梁数量降低,骨小梁分离度显著增高(P<0.01);与模型组相比,治疗组的骨密度、骨体积分数、骨小梁数量增加,骨小梁分离度明显下降(P<0.01);③模型组中的ERK1、JNK mRNA表达和蛋白表达较假手术组明显增加(P<0.05,P<0.01);与模型组相比,治疗组中的ERK1、JNK mRNA表达和蛋白表达显著降低(P<0.05);④结果说明,伊班膦酸钠可能通过抑制ERK1、JNK丝裂原活化蛋白激酶信号通路的表达改善膝骨关节炎大鼠的软骨下骨的微结构,抑制软骨的退变。