动力髋螺钉与人工股骨头置换治疗高龄患者股骨粗隆间骨折的对比分析

[目的]对比分析动力髋螺钉内固定(DHS)与人工股骨头置换术治疗高龄股骨粗隆间骨折的临床疗效,评价两种手术治疗方案的优劣.[方法]选取2002年4月至2007年3月本院收治的高龄股骨粗隆间骨折患者69例,其中应用DHS手术内固定治疗37例,人工股骨头置换术治疗32例.对两组患者的手术时间、术中失血量、住院时间、卧床时间、并发症、疗效优良率等6项临床指标以及患侧髋关节功能评估进行统计学分析.[结果]所有患者均获得随访,随访时间6个月至3年,平均2.1年,6项临床指标均显示股骨头置换组疗效明显优于DHS组, 两组数据差异均有统计学意义(P＜0.05).[结论]人工股骨头置换术治疗高龄股骨粗隆间骨折较DHS内固定有明显优势,可作为临床治疗高龄股骨粗隆间骨折的一种合理选择.     

Thermotropic liquid crystals from biomacromolecules

Complexation of biomacromolecules (e.g., nucleic acids, proteins, or viruses) with surfactants containing flexible alkyl tails, followed by dehydration, is shown to be a simple generic method for the production of thermotropic liquid crystals. The anhydrous smectic phases that result exhibit biomacromolecular sublayers intercalated between aliphatic hydrocarbon sublayers at or near room temperature. Both this and low transition temperatures to other phases enable the study and application of thermotropic liquid crystal phase behavior without thermal degradation of the biomolecular components.Liquid crystals (LCs) play an important role in biology because their essential characteristic, the combination of order and mobility, is a basic requirement for self-organization and structure formation in living systems (1–3). Thus, it is not surprising that the study of LCs emerged as a scientific discipline in part from biology and from the study of myelin figures, lipids, and cell membranes (4). These and the LC phases formed from many other biomolecules, including nucleic acids (5, 6), proteins (7, 8), and viruses (9, 10), are classified as lyotropic, the general term applied to LC structures formed in water and stabilized by the distinctly biological theme of amphiphilic partitioning of hydrophilic and hydrophobic molecular components into separate domains. However, the principal thrust and achievement of the study of LCs has been in the science and application of thermotropic materials, structures, and phases in which molecules that are only weakly amphiphilic exhibit LC ordering by virtue of their steric molecular shape, flexibility, and/or weak intermolecular interactions [e.g., van der Waals and dipolar forces (11)]. These characteristics enable thermotropic LCs (TLCs) to adopt a wide variety of exotic phases and to exhibit dramatic and useful responses to external forces, including, for example, the electro-optic effects that have led to LC displays and the portable computing revolution. This general distinction between lyotropic LCs and TLCs suggests there may be interesting possibilities in the development of biomolecular or bioinspired LC systems in which the importance of amphiphilicity is reduced and the LC phases obtained are more thermotropic in nature. Such biological TLC materials are very appealing for several reasons. Most biomacromolecules were extensively characterized in aqueous environments, but in TLC phases, their solvent-free properties and functions could be investigated in a state in which no or only traces of water are present. Water exhibits a high dielectric constant and has the ability to form hydrogen bonds, greatly influencing the structure and functions of biomacromolecules or compromising electronic properties such as charge transport (12–15). Indeed, anhydrous TLC systems containing glycolipids (16–19), ferritin (20), and polylysine have been reported (21–23). However, a general approach to fabricating TLCs based on nucleic acids, polypeptides, proteins, and protein assemblies of large molecular weights such as virus particles remains elusive.Here we propose that the combination of biomaterials with suitably chosen surfactants, followed by dehydration, can be effectively applied as a simple generic scheme for producing biomacromolecular-based TLCs. We demonstrate that biological TLCs can be made from a remarkable range of biomolecules and bio-inspired molecules, including nucleic acids, polypeptides, fusion proteins, and viruses. TLC materials typically combine rigid or semirigid anisometric units, which introduce orientational anisotropy, with flexible alkyl chains, which suppress crystallization (24). In the present experiments, negatively charged biomolecules and bio-inspired molecules act as rigid parts, and cationic surfactants make up the flexible units to produce TLC phases with remarkably low LC-isotropic clearing temperatures, which is another TLC signature. Electrostatic interactions couple these rigid and flexible components into hybrid assemblies, which then order into lamellar phases of alternating rigid and flexible layers (Fig. 1) stabilized by the tendency in TLCs for rigid and flexible to spatially segregate (25).Open in a separate windowFig. 1.Proposed structures of TLCs formed by the biological building blocks complexed with surfactants, showing sketches of various lamellar phases and the corresponding phase transition temperatures (°C). The lamellar bilayer structures are made of, alternately, a sublayer of the biomacromolecules and an interdigitated sublayer of the surfactants, where the negatively charged parts of the biomolecules (e.g., phosphate groups of ssDNA and ssRNA, glutamate residues of supercharged ELPs, and N-terminal glutamate and aspartate residues of pVIII protein in phages) electrostatically interact with the cationic head groups of the surfactants. For the ssDNA–DOAB and ssRNA–DOAB smectic TLCs, the oligonucleotides are randomly orientated in the DNA (RNA) sublayers. For the ELP–DDAB complexes, in addition to the bilayer smectic phase, a modulated smectic (Sm_mod) phase is observed at lower temperature. For the phage–DOAB–DDAB lamellar structures, rodlike virus particles are embedded in a sublayer between interdigitated surfactants with additional in-plane orientational order.     

Dexmedetomidine-induced atrioventricular block followed by cardiac arrest during atrial pacing: a case report and review of the literature

Sinus bradycardia is a well-known consequence of stimulation of presynaptic α₂ adrenergic receptors due the adminstration of dexmedetomidine. One of the most serious adverse effects of dexmedetomidine is cardiac arrest. Some cases demonstrating such an arrest due to the indiscriminate use of this drug were recently reported. We continuously administered dexmedetomidine to a 56-year-old male patient at a rate of 0.3 μg/kg/h (lower than the recommended dose) without initial dosing for sedation in an intensive care unit. The patient had undergone open cardiac surgery and atrial pacing was maintained at a fixed rate, 90/min. The PQ interval in electrocardiography gradually prolonged during the infusion; finally, complete atrioventricular block and subsequent cardiac arrest occurred. Immediate cardiopulmonary resuscitation was carried out, including re-intubation, and recovery of spontaneous circulation was attained 15 min after the event. The patient was discharged from hospital on the 25th postoperative day without any neurological complications.     

肺感染致多器官功能障碍综合征血清瘦素浓度的变化

目的检测肺部严重感染所致多器官功能障碍综合征(MODS)、急性心肌梗死(AMI)和心律失常(AR)等危重症患者血清中瘦素(Leptin)及相关因子水平的变化,探讨Leptin在MODS发病及诊断中的可能意义。方法采用放射免疫分析法测定Leptin、脂肪酸结合蛋白(FABP)、转铁蛋白(Ferr)以及白细胞介素1β(IL1β)水平,采用酶联免疫吸附法(ELISA)测定C反应蛋白(CRP)水平。结果与正常对照组相比,Leptin水平在MODS、AMI和AR组均明显增高(P均<0.01);CRP和IL1β水平在MODS、AMI和AR组均显著增高(P<0.05或P<0.01),以MODS组患者增高更明显(P均<0.05);FABP和Ferr在3组患者中也均有明显上升趋势,特别是在MODS组中上升更多,但统计学上差异无显著性。结论肺感染所致MODS患者血清中Leptin水平明显上升,伴有CRP和IL1β同时升高,Leptin可能在MODS的发生和转归中发挥一定作用。     

阿伐他汀调节大鼠脊髓损伤后白细胞介素1β及半胱氨酸蛋白酶3基因的表达

目的:观察阿伐他汀对脊髓损伤后SD大鼠白细胞介素1β及半胱氨酸蛋白酶3基因表达的影响。方法:实验于2005-05/09在华中科技大学同济医学院附属同济医院矫形外科实验室完成。选择健康成年雌性SD大鼠78只,随机数字表法分为假手术组6只,阿伐他汀治疗组36只和生理盐水对照组36只,后两组每组又分损伤后1,4,12h,1,3,7d6个时相点,每个时相点6只。阿伐他汀治疗组于损伤前7d开始用阿伐他汀加生理盐水经口给药(5mg/kg,1次/d)直至处死,生理盐水对照组用相同体积的生理盐水代替。采用Allen打击法造成大鼠脊髓损伤,于术后不同时相点取伤段脊髓组织,用反转录-聚合酶链反应分析脊髓受损部位白细胞介素1β及半胱氨酸蛋白酶3mRNA表达。结果:纳入动物78只,均进入结果分析。①阿伐他汀治疗组大鼠脊髓损伤后4h白细胞介素1βmRNA表达(A)低于生理盐水对照组(分别为0.480±0.100,2.610±0.330,P<0.01)。②阿伐他汀治疗组大鼠脊髓损伤后1d半胱氨酸蛋白酶3mRNA表达(A)低于生理盐水对照组(分别为0.589±0.056,0.676±0.072,P<0.05)。结论:阿伐他汀能降低大鼠脊髓损伤后炎性细胞因子白细胞介素1β及半胱氨酸蛋白酶3的基因表达。     

Enzymatic determination of serum ethanol with membrane-bound dehydrogenase

In this enzymatic method for detecting ethanol in blood by use of membrane-bound microbial alcohol dehydrogenase (no EC no. assigned), the enzyme catalyzes the reaction irreversibly and the rate of oxidation can be monitored by spectrophotometry of the reduction of the indicator dye. No pyridine nucleotides such as NAD+ or NADP+ are used. The calibration curve is linear in the range of 0.1 to 4.0 g of ethanol per liter. Assays of 45 samples of serum having ethanol values ranging from 0.4 to 3.2 g/L by the described technique and a gas-chromatographic method gave respective means of 1.734 and 1.732 g/L (r = 0.954).