椎间盘软骨终板退变的研究进展

椎间盘的退变与多种因素相关,其中软骨终板作为椎间盘的组成部分,通过其渗透作用为椎间盘提供大部分营养,在维持椎间盘正常功能方面发挥重要作用。软骨终板退变作为椎间盘退变的始动因素近来受到广泛关注。软骨终板退变的具体机制尚不明确,但现有研究表明其退变与年龄、异常应力、局部炎症因子、软骨细胞凋亡、软骨基质退变等因素相关,深入研究各因素在终板退变过程中的具体作用机制将为治疗椎间盘退变性疾病提供新的方法,现对软骨终板退变的主要因素做如下综述。     

生物钟与椎间盘退变的研究进展

椎间盘退变在老年群体的发病率很高,且呈现出年轻化趋势,是导致下腰痛最常见的原因。在椎间盘退变的过程中,椎间盘细胞的功能出现异常,细胞合成和分解代谢异常,细胞外基质成分降解,细胞死亡增加,最终导致椎间盘结构和功能异常。椎间盘是高度节律化的器官,每日经历着运动和休息状态产生的周期性力学载荷变化,而工作倒班或者飞行时差等节律扰乱行为,增加了慢性下腰痛的发生率,这提示生物钟破坏可能是导致椎间盘退变的重要因素。本文对生物钟紊乱如何导致椎间盘退变进行了系统回顾,并总结了靶向生物钟基因调控网络各个环节的干预策略,为预防和治疗椎间盘退变提供时间治疗学新思路。     

椎间盘退变影响因素研究进展

椎间盘退变是由多种因素影响所致。长期过高和过低的压力负荷均为椎间盘退变的病因之一。近年研究证实软骨终板钙化引起的椎间盘营养供应减少可能是启动椎间盘退变的关键因素。椎间盘老化或营养供应障碍时椎间盘细胞合成一些细胞因子,影响细胞活性和细胞间信息交流,导致细胞凋亡。椎间盘内环境改变后激活潜伏状态的降解酶,使椎间盘基质分解加速,导致椎间盘退变。该文就生物力学、营养、细胞凋亡、细胞因子及降解酶等因素对椎间盘退变的影响及作用机制,作一综述。     

白细胞介素在椎间盘退变中的作用

椎间盘退变引起的下腰痛严重影响着老年患者的健康，同样也给社会和家庭带来巨大的负担。椎间盘退变从18岁开始，由于年龄、生物力学、生物化学、自身免疫炎症反应和遗传易感等因素的影响，加速椎间盘退变的过程。椎间盘退变是一个序贯、级联发生的病理过程，从椎间盘细胞微环境的改变开始，发展为椎间盘结构和功能的改变，其主要病理特征是炎症细胞因子，如白细胞介素（interleukins, ILs）的释放，促分解代谢酶的表达增加，细胞外基质降解，椎间盘细胞凋亡等。在椎间盘退变过程中白细胞介素起到了重要作用，本文将对白细胞介素在椎间盘退变中的作用进行综述。     

微小RNA在椎间盘退变中的研究进展

目的总结微小RNA(micro RNA)在椎间盘退变中的研究进展,分析其在椎间盘退变中的研究方向和临床应用潜能。方法广泛查阅国内外有关micro RNA在椎间盘退变中作用的相关文献并进行综述。结果micro RNA是通过对基因表达进行调控,从而影响椎间盘细胞的增殖与凋亡、增加退变椎间盘组织的炎性介质和蛋白酶等方式在椎间盘退变中发挥重要作用。结论 micro RNA是椎间盘退变领域的研究新热点,对micro RNA的研究将有助于明确椎间盘退变的发病机制,同时为椎间盘退变疾病的诊断与治疗提供了新思路。     

长链非编码RNA及其介导椎间盘退变机制的研究进展

椎间盘位于椎体之间,由髓核、纤维环和软骨终板构成,其主要成分为蛋白多糖、胶原纤维、弹性蛋白和水。因其特殊的解剖结构,血液供应和营养状况有限以及常处于应力状态下,在外伤、职业、妊娠、遗传及先天发育异常等因素作用下,极易发生退变。随着椎间盘退变机制研究的深入,发现长链非编码RNA(LncRNA)可能通过调控髓核细胞凋亡、细胞外基质降解,参与炎症反应等过程,在椎间盘退变的发生、发展中起到重要作用。本文拟对长链非编码RNA的特点及其介导椎间盘退变的不同机制作一综述。     

颈椎术后邻近节段退变研究进展

脊柱融合固定是众多脊柱疾病行之有效的治疗方法,但随着时间的推移,部分患者手术邻近节段逐渐退变并出现症状,从而引发对其发病率、发病机制、影响因素、预防治疗策略等的大量研究.一般认为颈椎前路融合固定较后路融合固定更易引起邻近节段退变,本身已有退变者术后退变发病率更高.颈椎术后邻近节段退变的确切机制还不清楚,但融合内固定、部位脊柱生理曲度异常等引起生物力学应力改变、邻近节段活动度增加、关节面载荷和椎间盘内压力增加在病程发展中起重要作用.影响邻近节段退变的因素还包括融合节段的多少、融合术式和部位、邻近椎间盘状况、术前疾病类型等.尽可能地保留运动节段能减少邻近节段退变的发生率,人工颈椎间盘置换等治疗效果良好.     

基质金属蛋白酶(MMPs)与椎间盘退变

椎间盘退变的近期相关研究提示细胞外基质成分的变化可能是直接导致其退变的一个重要因素.细胞外基质成分的改变与基质金属蛋白酶的作用密切相关,该酶的很多特性使其成为椎间盘退变的研究中的热点.本文对近期基质金属蛋白酶与椎间盘退变的相关研究加以综述,供科研工作者参考.     

代谢性疾病与椎间盘退变关系的研究进展

正椎间盘退变性疾病引起的慢性腰腿痛、颈肩痛严重影响了人们的正常生活,给社会带来了巨大的经济负担~([1])。近年来随着老龄人口增多和工作方式改变,与椎间盘退变相关的疾病发病人数不断增加,且发病年龄有不断提前的趋势~([2])。椎间盘退变受年龄、生活方式、遗传等多种因素的影响。但是关于椎间盘退变的确切机制尚不清楚,目前研究主要集中在生物力学因素、细胞因子及炎症介质、细胞营养缺乏及代谢紊乱、椎间盘细胞衰老、凋亡及遗传因素     

椎间盘退变的基因治疗

下腰痛是一种常见病、多发病,它影响人们的生活质量和精神状态,成为困扰人类的疾病之一［1-3］。很多因素都会导致下腰痛,其中椎间盘退变是最重要的因素之一［4］。目前临床上针对椎间盘退变引起相关疾病的治疗策略是解除椎间盘退变相关的脊髓、神经和血管刺激或压迫,并非针对椎间盘退变的病理过程,因而临床症状可反复发作,而且手术后病变节段的相邻节段椎间盘退变加速［5-6］。随着科学技术的发展,特别是分子生物学技术不断进步,延缓甚至逆转椎间盘退变正成为可能。目前治疗椎间盘退变的分子生物学技术主要包括三大类：细胞治疗、组织工程治疗及基因治疗。本综述主要着重基因治疗。     

Vasopressor hormone response following mesenteric traction during major abdominal surgery

Background : We investigated the vasopressor hormone response following mesenteric traction (MT) with hypotension due to prostacyclin (PGI₂) release in patients undergoing abdominal surgery with a combined general and epidural anesthesia. Methods : In a prospective, randomized, placebo-controlled study we administered 400 mg ibuprofen (i.v.) in 42 patients scheduled for abdominal surgery. General anesthesia was combined with epidural anesthesia (T4-L1). Before as well as 5, 15, 30, 45, and 90 min after MT we recorded plasma osmolality, hemodynamics and measured 6-keto-PGFlα (stabile metabolite of PGI₂), TXB₂ (stabile metabolite of thromboxane A₂) active renin, and arginine vasopressin (AVP) plasma concentrations by radioimmunoassay. Catecholamine levels were assessed by high-pressure liquid chromatography (HPLC) with electrochemical detection. Results : Following MT, arterial hypotension occurred along with a substantial PGI₂ release. This was completely abolished by ibuprofen administration. Although plasma levels of 6-keto-PGF_1α (1133 (708) vs. 60 (3) ng/L, median (median absolute deviation), P=0.0001, placebo vs. ibuprofen) remained significantly elevated, blood pressure was restored within 30 min after MT in the placebo group. At the same point in time plasma concentrations of TXB² (164 (87) vs. 58 (1) ng/L, P=0.0001), epinephrine (46 (33) vs. 14 (6) ng/L, P=0.001), AVP (41 ± (18) vs. 12 (7) ng/L, P=0.0004), and active renin (27 (12) vs. 12 (4) ng/L, P = 0.001) were significantly higher in placebo-treated patients. Conclusion : Under combined general and epidural anesthesia arterial hypotension following MT due to endogenous PGI₂ release is associated with enhanced release of AVP, active renin, epinephrine and thromboxane A₂, presumably contributing to hemodynamic stability within 30 min after MT.     

Microspheres Based Detoxification System: A New Method in Convective Blood Purification

Abstract: A variety of protein-bound or hydrophobic substances, accumulating as a result of pathologic conditions such as exogenous or endogenous intoxications, are removed poorly by conventional detoxification methods because of low accessibility (hemodialysis), insufficient adsorption capabilities (hemosorption), low efficiency (peritoneal dialysis), or economic limitations (high-volume plasmapheresis). Combining advantages of existing methods with microspheric technology, a module-based system was designed. Major operating parameters of the latter can be modified to allow for adjustment to individual clinical situations. An extracorporeal blood circuit including a plasmafilter is combined with a secondary high-velocity plasma circuit driven by a centrifugal pump. Different microspheric adsorbers can be combined in one circuit or applied in sequence. Thus, a prolonged treatment can be tailored using specially designed selective adsorber materials. Comparing this system with existing methods (high-flux hemodialysis, molecular adsorbent recycling system), results from our in vitro studies and animal experiments demonstrate the superior efficiency of substance removal.     

Bariatric Surgery in Some "Central and East-European (former Eastern bloc)"Countries - Current Status and Prediction for the Next Millennium

Background: Obesity is increasing globallly, including in the formerly "Eastern Bloc" countries. Methods: A survey was made of obesity and bariatric surgery. Results: In the 8 East and Central European countries studied, with total population 300 million, roughly 43% of the population was overweight (BMI 25-30), 23% obese (BMI > 30), with about 15 million people morbidly obese (BMI > 40). From 0-10 morbidly obese individuals/100,000/year undergo bariatric surgery. Conclusion: Most countries were found to provide inadequate treatment for obesity.The majority of the morbidly obese are not treated effectively. However, health-care awareness of obesity and bariatric surgeons are slowly increasing.     

Synergistic interaction between the effects of propofol and midazolam with fentanyl on phrenic nerve activity in rabbits

Background: It has been shown that the depressive effects of both propofol and midazolam on consciousness are synergistic with opioids, but the nature of their interactions on other physiological systems, e. g. respiration, has not been fully investigated. The present study examined the effect of propofol and midazolam alone and in combination with fentanyl on phrenic nerve activity (PNA) and whether such interactions are additive or synergistic. Methods: PNA was recorded in 27 anaesthetised and artificially ventilated rabbits. In three groups, propofol, fentanyl and midazolam were administered intravenously in incremental doses to construct dose-response curves for the depressant effects of each one on PNA. In another two groups, the effect of pretreatment with either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. on the effects of propofol and fentanyl respectively on PNA were studied. Results: Propofol and fentanyl caused a dose-dependent depression of PNA with complete abolition at the highest total doses of 16 mg · kg^?1 i. v. and 32 μg · kg^?1 i. v., respectively. In contrast, midazolam in incremental doses to a total of 0.8 mg · kg^?1 reduced mean PNA by 63%, but approximately 12% of PNA remained at a total dose as high as 6.4 mg · kg^?1. The mean ED₅₀s, calculated from dose-response curves, were 5.4 mg · kg^?1, 3.9 μg · kg^?1 and 0.4 mg · kg^?1 for propofol, fentanyl and midazolam, respectively. Initial doses of either fentanyl 1 μg · kg^?1 i. v. or midazolam 0.05 mg · kg^?1 i. v. acted synergistically with subsequent doses of either propofol or fentanyl to abolish PNA at total doses of 8 mg · kg^?1 and 8 μg · kg^?1, respectively. Conclusion: Fentanyl has a synergistic interaction with both propofol and midazolam on PNA and hence potentially on respiration.     

Influence of dopexamine hydrochloride on haemodynamics and regulators of circulation in patients undergoing major abdominal surgery

Background: Catecholaminergic support is often used to improve haemodynamics in patients undergoing major abdominal surgery. Dopexamine is a synthetic vasoactive catecholamine with beneficial microcirculatory properties. Methods: The influence of perioperative administration of dopexamine on cardiorespiratory data and important regulators of macro- and microcirculation were studied in 30 patients undergoing Whipple pancreaticduodenectomy. The patients received randomized and blinded either 2 μg · kg^?1 · min^?1 of dopexamine (n=15) or placebo (n=15, control group). The infusion was started after induction of anaesthesia and continued until the morning of the first postoperative day. Endothelin-1 (ET-1), vasopressin, atrial natriuretic peptide (ANP), and catecholamine plasma levels were measured from arterial blood samples. Measurements were carried out after induction of anaesthesia, 2 h after onset of surgery, at the end of surgery, 2 h after surgery, and on the morning of the first postoperative day. Results: Cardiac index (CI) increased significantly in the dopexamine group (from 2.61±0.41 to 4.57±0.78 1 · min^?1 · m^?2) and remained elevated until the morning of the first postoperative day. Oxygen delivery index (DO₂I) and oxygen consumption index (VO₂I) were also significantly increased in the dopexamine group (DO₂I: from 416±91 to 717±110 ml/m² · m²; VO₂I: from 98±25 to 157±22 ml/m² · m²), being significantly higher than in the control group. pHi remained stable only in the dopexamine patients, indicating adequate splanchnic perfusion. Vasopressive regulators of circulation increased significantly only in the untreated control patients (vasopressin: from 4.37±1.1 to 35.9±12.1 pg/ml; ET-1: from 2.88±0.91 to 6.91±1.20 pg/ml). Conclusion: Patients undergoing major abdominal surgery may profit from prophylactic perioperative administration of dopexamine hydrochloride in the form of improved haemodynamics and oxygenation as well as beneficial influence on important regulators of organ blood flow.     

Systemic analgesia adapted to the children's condition

A concept of balanced analgesia using nonsteroidal anti-inflammatory drugs (NSAIDs), paracetamol (acetaminophen), opioids, and corticosteroids can also be used in patients with pre-existing illnesses. NSAIDs are the most effective treatment for acute pain of moderate intensity in children; however, these drugs should be avoided in patients at increased risk for serious side effects, e.g. patients with renal impairment, bleeding tendency, or extreme prematurity. NSAIDs can be given with minimal risks to the younger child with mild to moderate asthma, and, in these patients, the use of steroids can be encouraged; in addition to their antiemetic and analgesic action, a beneficial effect on asthma symptoms can be expected. In the non-intubated child with cerebral trauma, exaggerated sedation caused by opioids and increased bleeding tendency caused by NSAIDs must be avoided. In neonates and small infants, the oral administration of sucrose or glucose is helpful to minimize pain reaction during short uncomfortable interventions.     

Intraoperative autotransfusion is associated with modest reduction of allogeneic transfusion in prosthetic hip surgery

Background: The efficacy of intraoperative salvage and washing of wound blood and the predictors of allogeneic red cell transfusions in prosthetic hip surgery are insufficiently known.
Methods: In 96 patients, undergoing primary or revision surgery, salvaged and washed red cells and, if necessary, allogeneic blood were used to keep haematocrit not lower than 33%. The bleeding of red cells during hospital stay was calculated from the red cell balance. The preoperative red cell reserve (millilitres of red cells in excess of a haematocrit of 33%) was estimated and the difference between this volume and the total bleeding of red cells was retrospectively used to classify patients with regard to the need for red cells. Stepwise regression analysis was used to define patient-related variables associated with allogeneic blood transfusion.
Results: Preoperative knowledge of the type of operation (primary, revision), the preoperative red cell reserve, and the body mass could predict roughly half of the need for banked blood (r²=0.45). Only one-third of the total bleeding of red cells was retransfused. For complete avoidance of allogeneic blood, autotransfusion was most effective in patients with a moderate need (0–4 u). However, 32% of such patients required allogeneic blood.
Conclusions: Autotransfusion has a limited efficacy to decrease the need for allogeneic blood, and other blood-saving methods should be added for this purpose. It is difficult to predict the need for allogeneic blood preoperatively.     

缺氧对肾小管上皮细胞分泌外泌体的影响

目的    观察缺氧对肾小管上皮细胞分泌外泌体的影响,探讨外泌体在缺氧致肾脏损伤中的作用及机制。 方法    （1）常氧（21% O₂）及缺氧（1% O₂）分别处理大鼠肾小管上皮细胞（NRK-52E）48 h,收集细胞上清液并使用高速梯度离心法分离外泌体。采用透射电镜、纳米示踪分析、Western印迹、蛋白浓度定量鉴定并比较两组外泌体的基本特性。（2）在共培养实验中,以不同浓度（1、10、50、100、300 mg/L）的常氧外泌体、缺氧外泌体分别干预脂多糖（LPS）诱导的大鼠原代腹腔巨噬细胞,使用实时荧光定量PCR与酶联免疫吸附试验（ELISA）法分别检测巨噬细胞白细胞介素6（IL-6）、肿瘤坏死因子α（TNF-α）、诱导型氮氧化物合酶（iNOS）水平;使用Western印迹法检测巨噬细胞磷酸化（p）STAT/STAT及细胞因子信号传导抑制蛋白1（SOCS1）的蛋白表达;最后,使用实时荧光定量PCR法检测常氧外泌体与缺氧外泌体中炎性反应相关微RNA（microRNA,miR）的表达差异。 结果    （1）离心得到的囊泡具有外泌体典型的结构,粒径小于150 nm,表达外泌体标志蛋白CD63,说明分离得到外泌体。缺氧对肾小管上皮细胞分泌的外泌体形态、粒径分布比例无明显影响,但提高了外泌体的分泌量。（2）缺氧外泌体相比于常氧外泌体促进了LPS诱导的M1型巨噬细胞IL-6、TNF-α、iNOS 的表达和分泌（均P＜0.01）,同时提高STAT的磷酸化水平并减少SOCS1的蛋白表达（均P＜0.01）;对炎性反应相关microRNA检测发现缺氧外泌体中miR-155、miR-27a表达量较常氧外泌体明显升高（P＜0.05）。 结论    缺氧可改变外泌体的生物学功能,表现为协同促进LPS诱导的M1型巨噬细胞的表型转化,这可能是慢性肾脏病微炎性反应状态持续的原因之一。     

In Vitro Function and Durability Assessment of a Novel Polyurethane Heart Valve Prosthesis

Abstract While flexible-leaflet, central-flow prosthetic heart valves promise relief from anticoagulation therapy, they continue to be restricted by inadequate durability. In consequence, a novel trileaflet valve, made entirely from polyurethane, has been developed. A batch of 6 consecutively manufactured polyurethane valves was subjected to hydrodynamic function and accelerated fatigue testing. Computerized data acquisition and control systems have been introduced to improve valve testing methodologies. In terms of hydrodynamic function, the polyurethane valve demonstrates transvalvular pressure gradients similar to those for a bioprosthetic valve (Carpentier-Edwards) and levels of retrograde flow significantly less than those for either the bioprosthetic valve or a bileaflet mechanical valve (St Jude Medical). The equivalent of 10 years of cycling without failure has been exceeded by all 6 polyurethane valves in accelerated fatigue tests with 2 valves remaining intact after 674 million cycles (equivalent to approximately 17 years) in continuing tests. Highspeed photography revealed considerable differences in leaflet motion between valves cycled at accelerated and physiological rates.     

Negative pressure ventilation vs. spontaneous assisted ventilation during rigid bronchoscopy: A controlled randomised trial

Background: Ventilation during interventional rigid bronchoscopy (IRB) under general anaesthesia (jet ventilation, positive pressure ventilation and spontaneous assisted ventilation) may offer some difficulties. This study compares the effectiveness during IRB of intermittent negative pressure ventilation (INPV) and spontaneous assisted ventilation (SAV). Methods: Thirty-eight patients submitted to IRB were randomised into two groups: SAV or INPV. All patients received a total intravenous anaesthesia; INPV patients were paralysed. Pre-and intra-operative arterial blood gases and O₂ flow through a rigid bronchoscope were assessed. The endoscopist applying a subjective score evaluated the operating conditions. Results: Patients of the INPV group, as compared to the SAV group, required a lower dosage of fentanyl (2.6 ± 1.8 (μg · kg^?1· h^?1 vs. 6.6 ± 4.8 μg · kg^?1· h^?1), a lower O₂ supply (3.3 ± 2.8 1/min vs. 11.6 ± 3.4 1/min), a shorter recovery time (5.4 ± 2.9 min vs. 9.8 ± 7.1 min) and no manually assisted ventilation (0 ± 0 vs. 1 ± 1.1 nd?/procedure). Intraoperative PaCO₂ was higher in the SAV (8.1 ± 1.3 kPa) than in the INPV group (5.0 ± 1.6 kPa) and intraoperative pH differed in the two groups (7.26 ± 0.05, SAV vs. 7.47 ± 0.08, INPV). Operating conditions, as assessed by a subjective score, were considered better with INPV than with SAV (4.9 vs. 4.3). Conclusions: As compared to SAV, INPV in paralysed patients during IRB reduces administration of opioids, shortens recovery time, prevents respiratory acidosis, excludes the need for manually assisted ventilation, reduces 02 need and affords optimal surgical conditions. INPV appears a safe, non-invasive and effective ventilatory management during IRB.