磷酸钙水泥填充固定桡骨远端骨折的抗旋转生物力学研究

目的对磷酸钙水泥(CPC)填充固定桡骨远端骨折的抗旋转应力进行评价,并与传统的克氏针固定方法进行比较。方法18根人桡骨标本制备桡骨远端骨折伴骨缺损模型,随机分为三组:克氏针固定组、CPC固定组和CPC 克氏针联合固定组。设定扭转速度为5°／min,最大扭转角度为10°时停止。记录扭转刚度、10°内的最大扭矩及所对应的最大扭角。结果在10°的扭转范围内,CPC固定组、CPC 克氏针联合固定组的扭转刚度、最大扭矩均比克氏针固定组大,差异有统计学意义(P< 0．01);最大扭转角度分别为4．3°和5．0°,均比克氏针组(9．6°)小,差异有统计学意义(P<0．01)。CPC固定组与CPC 克氏针联合固定组之间的扭转刚度、最大扭矩及最大扭角差异无统计学意义(P> 0．05)。结论在旋转角度小于4°范围内,CPC的抗旋转固定强度要比克氏针大,超过这个范围,骨水泥就会发生断裂,CPC的有效固定范围比克氏针要小。     

苄丙酮香豆素对实验性大鼠肾草酸钙结石形成的影响

目的：探讨Vit．K拮抗剂苄丙酮香豆素(商品名华法令)对大鼠肾草酸钙结石形成的影响。方法：采用乙二醇饮水和氯化铵灌胃作成石剂，30只Wistar大鼠随机分为对照组(A组)、成石组(B组)、华法令组(C组)。饲养4周后，检测大鼠肾组织钙含量和草酸钙晶体形成、24h尿钙、尿草酸含量及血生化指标。结果：成石组和华法令组肾组织中钙、镁含量，24h尿草酸及尿钙、镁排泄量差异无显著性意义；镜下观察发现：华法令组大鼠肾脏草酸钙结晶形成多于成石组，但组间比较差异无显著性意义。结论：苄丙酮香豆素对大鼠肾草酸钙结石的形成无显著影响。     

自固化磷酸钙人工骨修复骨缺损的临床应用

目的:探讨自固化磷酸钙人工骨(CPC)填充修复骨缺损的临床效果。方法:骨缺损94例,男59例,女35例;年龄11~72岁,平均39.4岁。骨缺损部位:胸腰椎38例,跟骨25例,胫骨15例,股骨7例,肱骨近端3例,桡骨远端5例,近节指骨1例。骨缺损原因:骨折塌陷复位后骨缺损63例,骨髓炎20例,骨囊肿6例,骨纤维异常增殖症4例,内生软骨瘤1例。骨缺损范围为1cm×1cm~4cm×20cm,用CPC填充修复,CPC充填量为3~42g,其中单纯CPC填充修复74例(胸腰椎骨折行椎体成形38例,骨折复位后空腔充填25例,良性骨肿瘤病灶刮除后充填11例),载药CPC填充修复骨髓炎20例。结果:所有患者均获随访,随访时间14~48个月,平均29.6个月。全部患者术后未见过敏或毒性反应,无皮疹或高热,血钙、磷、碱性磷酸酶均正常,切口无瘙痒感。随访时X线片显示,植入CPC与宿主骨接触紧密,界面处未见间隙存在,骨缺损处的解剖形状完全或大部分恢复,未见脱落现象,随访时部分患者CPC部分降解成骨。9例发生术后伤口渗出,为淡黄色清亮稀薄分泌物,细菌培养阴性,经换药后伤口愈合良好。结论:CPC填充修复骨缺损安全有效,并发症少,是理想的骨替代品,载药CPC是治疗骨髓炎的理想方法。     

高效液相色谱法同时测定兔血清中普罗帕酮和奎尼丁的浓度

目的 :建立高效液相色谱法同时测定家兔血清普罗帕酮和奎尼丁的浓度。方法 :应用YWG -C18(5mm×150mm) ,流动相为甲醇 :醋酸钠 -醋酸缓冲液 :二乙胺 :水 (70 :24.5:0.5:5) ,紫外波长254nm检测。结果 :普罗帕酮、奎尼丁平均回收率分别为99.1 % ,97.9 % ,日内日间精密度分别为 (2.2～3.9) %,(2.6～4.4) %。结论 :方法简单、灵敏、准确 ,可用于临床治疗药物监测。     

Mutant ryanodine receptors in catecholaminergic polymorphic ventricular tachycardia generate delayed afterdepolarizations due to increased propensity to Ca2+ waves.

AIMS: Mutations in cardiac ryanodine receptors (RyR2s) are linked to catecholaminergic polymorphic ventricular tachycardia (CPVT), characterized by risk of polymorphic ventricular tachyarrhythmias and sudden death during exercise. Arrhythmias are caused by gain-of-function defects in RyR2, but cellular arrhythmogenesis remains elusive. METHODS AND RESULTS: We recorded endocardial monophasic action potentials (MAPs) at right ventricular septum in 15 CPVT patients with a RyR2 mutation (P2,328S, Q4,201R, and V4,653F) and in 12 control subjects both at baseline and during epinephrine infusion (0.05 microg/kg/min). At baseline 3 and during epinephrine infusion, four CPVT patients, but none of the control subjects, showed delayed afterdepolarizations (DADs) occasionally coinciding with ventricular premature complexes. In order to study the underlying mechanisms, we expressed two types of mutant RyR2 (P2,328S and V4,653F) causing CPVT as well as wild-type RyR2 in HEK 293 cells. Confocal microscopy of Fluo-3 loaded cells transfected with any of the three RyR2s showed no spontaneous subcellular Ca(2+) release events at baseline. Membrane permeable cAMP analogue (Dioctanoyl-cAMP) triggered subcellular Ca(2+) release events as Ca(2+) sparks and waves. Cells expressing mutant RyR2s showed spontaneous Ca(2+) release events at lower concentrations of cAMP than cells transfected with wild-type RyR2. CONCLUSION: CPVT patients show DADs coinciding with premature action potentials in MAP recordings. Expression studies suggest that DADs are caused by increased propensity of abnormal RyR2s to generate spontaneous Ca(2+) waves in response to cAMP stimulation. Increased sensitivity of mutant RyR2s to cAMP may explain the occurrence of arrhythmias during exercise or emotional stress in CPVT.     

Gating modifier toxins of voltage-gated calcium channels.

Some of the most potent and specific inhibitors of voltage-gated calcium channels are peptide toxins that inhibit channel function not by occlusion of the channel pore, but rather by interfering with the voltage dependence and kinetics of channel opening and closing. Many such gating modifier toxins conform to the inhibitor cystine knot structural family and have primary sequence or functional mechanism similar to toxins that target voltage-gated sodium or potassium channels. This review introduces known gating modifiers of calcium channels, discusses the selectivity, binding sites, and mechanism of the toxin-channel interaction, and reviews the usefulness of these toxins as research tools and as the basis for novel calcium channel pharmacology and therapeutics.     

地高辛的体内分析方法应用与进展

目的总结地高辛血药质量浓度监测方法,寻求最适的测定方法。方法对近年来国内外与地高辛监测相关的文献进行检索综述分析。结果地高辛血药浓度测定方法很多,常用方法主要有:FPIA、酶免疫分析法、RIA、CLIA、乳胶免疫抑制法、干化学法、HPLC法等。结论通过比较分析其中RIA、CLIA、EIA和HPLC MS 4种方法更好。     

Electrocrystallization of calcium carbonate on carbon-based electrodes

Calcium carbonate was deposited by electrochemical reduction of oxygen to hydroxyl ions at various carbon-based electrodes. Although some vaterite was observed during earlier stages of the electrodeposition, the predominant polymorph during later stages was calcite. The average crystal size reached a value of 15 μm after 10 h at a glassy carbon electrode but the crystal growth rate was substantially accelerated when oxygen was catalytically reduced. The same average size of the calcite crystals in this case (Pt/C electrode) was reached within a period of 1.5 h. Efficient removal of CaCO₃ from water was demonstrated when using a porous aerogel carbon electrode and a potential sufficiently negative to promote reduction of water molecules within the pores.     

The Effects of Zero Magnesium Dialysate and Magnesium Supplements on Ionised Calcium Concentration in Patients on Regular Dialysis Treatment

The effect of oral magnesium carbonate aluminium hydroxide onserum ionised calcium, total calcium, aluminium and magnesium,was assessed in 31 patients with chronic renal failure, duringand after one haemodialysis. The behaviour of ionised calcium and total calcium was the samein both groups. Each showed a slight fall during dialysis, whichwas not significant. Serum total calcium was 0.2–0.3 mmol/l(0.8–1.2 mg/dl) greater throughout the period of dialysisin the group taking aluminium hydroxide. Serum magnesium andaluminium were both lower in the group treated with magnesiumcarbonate. In the group taking magnesium carbonate, serum magnesium concentrationsfell markedly during dialysis, but otherwise were maintainedwithin the reference range by the use of a magnesium-free dialysate.These results show the effectiveness of magnesium carbonateoral phosphate-binding agents and zero magnesium dialysate inreducing serum aluminium without affecting the behaviour ofserum calcium fractions during dialysis.     

Reassessment of the accuracy of traditional sperm characteristics and adenosine triphosphate (ATP) in estimating the fertilizing potential of human semen in vivo

Receiver operating characteristic curves and accuracy parameters were computed for traditional sperm characteristics (concentration, motility, morphology) and the number of peroxidase negative cells, and the concentration of adenosine triphosphate (ATP) in semen from populations of fertile and infertile men, and men who achieved a pregnancy after varicocele treatment. The percentage and concentration per millilitre of spermatozoa with rapid linear progressive motility, and the ATP concentration, provided the best discrimination between fertile and treated fertile from infertile men. The misclassification rate was higher for sperm morphology, total progressive motility and viability, whereas sperm concentration and the total sperm count per ejaculate had the worst discriminating power. The number of peroxidase negative cells per 100 spermatozoa was highly specific in identifying men who achieved pregnancy after varicocele treatment. The lower limit of normality of sperm characteristics was remarkably different between fertile men and men achieving pregnancy after treatment or during infertility work-up.