β-内酰胺类抗生素在胆汁中的浓度和药动学的实验研究

目的 研究β-内酰胺类抗生素在胆汁中的浓度及其药动学,并对杀菌效力进行评估,为临床上肝胆系统感染选择用药提供参考和依据.方法 家兔行胆总管造瘘术,分别静脉注射哌拉西林/他唑巴坦、头孢曲松和美罗堵南等β-内酰胺类抗生素后于不同时间收集胆汁标本,采用HPLC法测定各抗生素的浓度,并计算出药动学参数.结合最低抑菌浓度(MIC),评估抗生素在胆汁中的杀菌效力.结果 各抗生素在胆汁中的峰浓度和半衰期分别为:哌拉西林(7950.16±3023.00)μg/ml和(1.97±1.23)h,头孢曲松(1107.01±247.61)μg/ml和(3.14±0.57)h,美罗培南(31.97±12.44)μg/ml和(0.36±0.11)h.哌拉西林/他唑巴坦的杀菌指数最大、TMIC最长,对大部分胆道感染常见致病菌均可形成MIC90 100倍以上的浓度,TMIC长达6～8 h;头孢曲松和美罗培南较低.结论 哌拉西林、头孢曲松和美罗培南均可在胆汁中达到有效杀菌浓度,哌拉西林/他唑巴坦杀菌效力最强.     

抗菌药物在胆汁中药物代谢动力学特点的实验研究及杀菌效力评价

目的 探讨6种抗菌药物在胆汁中的药物代谢动力学特点,并评估其杀菌效力.方法 实验用健康家兔36只,随机分为6组,每组6只.行胆总管造瘘术后,分别静脉注射头孢曲松、头孢哌酮/舒巴坦钠、哌拉西林/他唑巴坦、美罗培南、左氧氟沙星、甲硝唑,于注射后不同时间收集家兔胆汁标本,采用高效液相色谱法测定各抗菌药物的浓度,并计算出药物代谢动力学参数.结合最低抑菌浓度(MIC)评估各抗菌药物在胆汁中的杀菌效力.结果 各抗菌药物在胆汁中的峰浓度和半衰期分别为:哌拉西林(7 950 ±3 023) mg/L和(1.97±1.23)h,头孢曲松(1 104±248) mg/L和(3.14±0.57)h,头孢哌酮(5 215 ±2 225) mg/L和(0.89 ±0.13)h,美罗培南(31.97 ±12.44) mg/L和(0.36±0.11)h,左氧氟沙星(66.3±36.9) mg/L和(3.32±2.57)h,甲硝唑(28.2±10.2) mg/L和(0.81 ±0.33)h.哌拉西林/他唑巴坦和头孢哌酮/舒巴坦的杀菌指数最大,分别为(62.1±23.6) ～(993.8±377.9)和(164.8 ±69.0) ～ (659.3 ±275.9),其药物浓度持续在MIC以上的时间(T＞MIC)最长,两药的T＞MIC分别为(6.00±2.53)～(8.00±0.00)h和(6.33±1.97) ～ (8.00±0.00)h;左氧氟沙星的杀菌指数[(2.1±1.2)～(8.3±4.6)]和T＞MIC[(0.54±0.25)～(2.67±1.03)h]最小,头孢曲松和美罗培南居中,其杀菌指数和T＞MIC分别为(4.3±1.0) ～ (69.2±15.5)、(1.42±0.65)～(8.00±0.00)h和(2.0±0.8)～(1 031.3 ±401.4)、(0.29 ±0.10) ～ (1.83 ±0.26)h.甲硝唑对厌氧菌的杀菌指数和T＞MIC分别为7.4 ～294.9和1.88 ～5.00 h.结论 6种抗菌药物均可在胆汁中达到有效杀菌浓度,哌拉西林、头孢哌酮、美罗培南、甲硝唑在家兔胆汁中呈一房室模型,头孢曲松、左氧氟沙星为二房室模型分布.哌拉西林/他唑巴坦和头孢哌酮/舒巴坦杀菌效力最强,甲硝唑对厌氧菌有较强的杀菌力,肝胆系统感染应结合临床选用杀菌效力强的抗菌药物.     

莫西沙星在胆道疾病手术中应用的前瞻性研究

目的 1.评价莫西沙星对胆道疾病手术病人的临床及细菌学疗效.2.观察莫西沙星治疗胆道疾病的安全性.方法 选取2008年6～ 10月确诊为胆道疾病行手术治疗的52例病人,随机分为实验组(莫西沙星治疗组,32例)和对照组(头孢哌酮/舒巴坦治疗组,20例).术中留取胆汁作细菌培养和药敏试验,并观察临床疗效.结果 41例病人胆汁共培养出48株细菌,另11例胆汁培养无菌生长,胆汁细菌培养阳性率为78.8％(41/52).菌株药敏结果和临床疗效两组间比较无显著差异(P＞0.05).莫西沙星治疗组有1例病人发生胸闷和气促.结论 莫西沙星是胆道疾病手术治疗病人一种可供选择的抗生素.     

利用秩和比法筛选尿石症合并尿路感染患者的经验性抗生素

目的利用秩和比(RSR)法筛选尿石症合并尿路感染(UTI)患者的经验性抗生素,为临床用药提供参考依据。方法回顾性分析2014年1月至2015年10月贵州医科大学附属医院泌尿外科收治的52例尿石症合并UTI患者的尿培养结果,利用秩和比法对主要的致病菌株进行药物敏感性分析,对临床常用抗菌药物按其敏感性的优劣进行排序分档。结果本研究结果显示尿石症患者UTI排前5位的病原菌依次为大肠埃希菌、肺炎克雷伯菌、肠球菌属、肠杆菌属、葡萄球菌属;临床常用抗菌药物按其敏感性优劣分成3档:低度敏感档:氨苄西林、头孢曲松、复方新诺明、环丙沙星、头孢呋辛、左氧氟沙星、头孢唑林;中度敏感档:庆大霉素、头孢噻肟、头孢吡肟、头孢他啶、氨苄西林-舒巴坦、头孢西丁;高度敏感档:哌拉西林-他唑巴坦、头孢哌酮-舒巴坦、亚胺培南、头孢他啶-克拉维酸、阿米卡星、呋喃妥因、美罗培南。结论尿石症患者UTI致病菌以大肠埃希菌和肺炎克雷伯杆菌为主,临床上可考虑将头孢哌酮-舒巴坦、哌拉西林-他唑巴坦等含β-内酰胺酶抑制剂的抗菌药物作为尿石症合并UTI患者经验性用药的首选。     

胆石症合并急性胆管炎患者胆汁及血液病原菌培养及药敏分析

目的观察胆石症合并急性胆管炎患者胆汁及血液中病原菌的分布特征、培养阳性率及其对抗菌药物的敏感性,指导临床合理选择和应用抗菌药物。方法选取2011年1月至2014年1月本院消化内科诊断为急性胆道感染、经内镜逆行性胰胆管造影术(ERCP)术中证实存在结石的97例患者的胆汁标本,所有胆汁标本均进行普通细菌、厌氧菌及真菌培养,其中33例行血培养,分别对其病原菌培养及药敏结果进行分析,同时对97例患者术前经验性应用的抗菌药物情况进行统计分析。结果 97例胆汁培养者中73例检出病原菌,阳性率为75.3%。胆汁标本中共分离出病原菌77株,其中革兰阴性菌60珠,革兰阳性菌14株,真菌3株,革兰阴性菌中排名居前3位的细菌分别是大肠埃希菌(43株,55.8%)、克雷伯菌属(6株,7.8%)、阴沟肠杆菌(4株,5.2%)。33例血培养者17例检出病原菌,阳性率为51.5%。血培养中分离出病原菌17株,大肠埃希菌15株,肺炎克雷伯菌1株,梭杆菌属1株。革兰阴性菌对头孢哌酮/舒巴坦、哌拉西林/他唑巴坦和阿米卡星敏感性较高(敏感率分别为93.3%、88.3%和83.3%),未发现对亚胺培南及美罗培南耐药者。对氨曲南和左氧氟沙星敏感性最低(敏感率均为23.0%)。97例患者术前均经验性应用抗菌药物,55例应用单一抗菌药物抗感染,主要为左氧氟沙星(34/55),其次为头孢哌酮/舒巴坦(11/55)和其他(10/55);42例两联抗感染治疗,主要为左氧氟沙星+甲硝唑(16/42)、头孢哌酮/舒巴坦+甲硝唑(15/42)和其他(11/42)。结论胆石症合并急性胆道感染者胆汁中及血液中的主要病原菌为革兰阴性菌,且均以大肠埃希菌为主。头孢哌酮/舒巴坦、哌拉西林/他唑巴坦、阿米卡星敏感性较高,可作为首选抗菌药物,亚胺培南、美罗培南作为备选抗菌药物,在严重感染或其他抗菌药物无效的情况下考虑使用。左氧氟沙星、氨曲南在胆道结石并胆道感染者中耐药率高,临床上经验性应用抗菌药物时应避免选用。     

美罗培南在家兔胆汁中的药物浓度-时间分布的实验研究

目的研究美罗培南在家兔胆汁中的浓度及其分布规律,为预防和治疗胆道感染用药提供参考和依据。方法家兔行胆总管造瘘术,先留取空白胆汁,静脉注射美罗培南后分别于不同时间点采集胆汁标本。行专属性试验后,取空白胆汁加美罗培南对照品和流动相,配成0.5~500μg/ml不同浓度的系列胆汁样品,经高效液相色谱仪分析,采用外标法行药物色谱峰面积定量,以胆汁样品药物浓度对色谱峰面积进行线性回归,得回归方程。注射美罗培南后的家兔胆汁样品经预处理后用高效液相色谱仪测定峰面积,按标准曲线回归方程计算得出胆汁药物浓度,从而了解美罗培南的胆汁药物浓度-时间分布情况。结果专属性试验显示,在本研究的流动相色谱条件下测定药物,胆汁杂质峰、美罗培南药物色谱峰分离效果良好。标准曲线回归方程为S=2209.10C-1251.34,r=0.9999,美罗培南的最低定量限为0.5μg/ml。家兔静脉注射美罗培南(75mg/kg)后即时在胆汁中达(38.36±14.17)μg/ml,远远超过其对革兰阴性杆菌的最小抑菌浓度(MIC90)0.031~2μg/ml,之后美罗培南的胆汁药物浓度随时间而迅速降低。用药后180min,胆汁中的药物均被完全消除。结论美罗培南在胆汁中能达到较高的有效杀菌浓度,可作为预防和治疗胆道感染的较佳的药物。由于消除速度较快,临床用药应缩短间隔时间。     

抗菌药物用药频度与铜绿假单胞菌和鲍曼不动杆菌耐药率的相关性

目的分析抗菌药物用药频度与铜绿假单胞菌和鲍曼不动杆菌耐药率的相关性,为临床合理使用抗菌药物,降低细菌耐药率提供依据。 方法对云南省第三人民医院2013年1月至2017年12月年常用抗菌药物用药频度以及同期分离的铜绿假单胞菌和鲍曼不动杆菌耐药情况进行回顾性调查分析。 结果本院抗菌药物2014年用药频度（28 809）较2013年（16 259）显著上升,铜绿假单胞菌对头孢曲松、头孢吡肟、氨曲南、庆大霉素、左氧氟沙星、亚胺培南、美罗培南、头孢哌酮/舒巴坦和哌拉西林/他唑巴坦的耐药率,鲍曼不动杆菌对头孢曲松、头孢吡肟、庆大霉素、亚胺培南、美罗培南、头孢哌酮/舒巴坦和哌拉西林/他唑巴坦抗菌药物的耐药率亦有所上升。鲍曼不动杆菌对头孢哌酮/舒巴坦较敏感,但对其他常用抗菌药物的耐药率,特别是对头孢类（平均耐药率为78.23%）和碳青霉烯类药物（平均耐药率为72.69%）的耐药率仍居高不下。抗菌药物年用药频度分析结果显示,2013年至2017年铜绿假单胞菌耐药率与左氧氟沙星用药频度呈高度正相关（r = 0.70、P = 0.20）;鲍曼不动杆菌耐药率与美洛培南用药频度呈显著正相关（r = 0.94、P = 0.02）。 结论本院所分离铜绿假单胞菌耐药率与左氧氟沙星用药频度,鲍曼不动杆菌耐药率与美洛培南用药频度均呈显著正相关,为避免常见的感染菌和定植菌耐药的发生,应加强抗菌药物的监管。     

院内感染嗜麦芽窄食单胞菌的临床分布及耐药分析

目的 研究嗜麦芽窄食单胞菌的分布及耐药特征。方法 收集我院2001年1月。2003年1月住院病人血及分泌物分离的嗜麦芽窄食单胞菌，符合院内感染并剔除重复株后共44株，复习临床资料及药敏结果。结果 感染最多见于呼吸道(32／44，72．7％)，最常见的危险因素为广谱抗生素、糖皮质激素的应用及侵袭性操作，药敏结果对大多数抗生素耐药，哌拉西林，他唑巴坦、头孢哌酮，舒巴坦的耐药率最低，分别为6．8％及9．1％。结论 嗜麦芽窄食单胞菌为常见的院内感染致病菌，ICU病房的分离率最高．合理使用抗生素、减少侵袭性操作、对该菌的药敏结果进行检测，有利于预防及控制医院嗜麦芽假单胞菌感染。     

胆囊切除术患者胆汁培养和药敏分析

目的 观察现阶段本中心胆囊切除术患者胆汁病原菌培养阳性率、菌株分布特征和对抗生素 的耐药性,以指导目前抗菌药物在胆道疾病中的合理应用。方法 选取2016年4月至2018年9月湛江市肿瘤医院普通外科诊断为胆囊结石伴急性胆囊炎、胆囊结石伴慢性胆囊炎、胆囊息肉伴慢性胆囊炎的患者 137例,行胆囊切除术,围手术期使用的抗生素主要为头孢孟多酯、头孢唑肟、头孢哌酮/舒巴坦+甲硝唑。 术后均留取胆汁标本,行胆汁细菌、厌氧菌和真菌培养,对病原菌培养和药敏结果进行分析。结果 137 例胆汁标本中62例培养出病原菌,阳性率45.3%,62株病原菌中革兰氏阴性菌22株（35.5%）,革兰氏阳性 菌37株（59.7%）,真菌 3株（4.8%）。排在第一位的菌株仍为大肠埃希菌。革兰阴性菌前2位为大肠埃希菌（10 株,16.2%）和肺炎克雷白杆菌（4株,6.5%）,革兰氏阳性菌前2位为粪肠球菌（9株,14.5%）和溶血葡萄球 菌（9株,14.5%）。药敏结果耐药性分析：革兰阴性菌对亚胺培南、美罗培南和哌拉西林/他唑巴坦的耐药 率最低（均为0）,其次为阿米卡星（4.7%）和头孢哌酮/舒巴坦（9.5%）。革兰氏阳性菌对万古霉素、利奈唑胺和阿米卡星耐药率最低（均为0）,其次为克林霉素（3.0%）、替考拉宁（3.1%）和左氧氟沙星（4.5%）。真菌对常见的抗真菌药两性霉素、氟康唑、伊曲康唑和伏立康唑未见有耐药。137例患者中有22例是胆囊息肉伴慢性胆囊炎,培养出病原菌7株,阳性率为31.8%。结论 本研究显示,胆囊切除术患者胆汁中的主要病原菌仍是大肠埃希菌,但胆汁培养中革兰氏阳性菌株占多数,可能原因为头孢类抗生素使用后革兰 氏阴性菌生长受到抑制以及革兰氏阳性菌感染近年来有上升趋势。胆囊结石伴急性胆囊炎患者术后可根 据临床经验选择抗生素治疗,而无手术条件患者行保守治疗首选哌拉西林/他唑巴坦或头孢哌酮/舒巴坦+ 甲硝唑,如果效果不佳可联用或改用克林霉素、万古霉素,或升级为亚胺培南、美罗培南治疗。胆囊息肉 伴慢性胆囊炎患者胆汁培养菌株阳性率较高,无症状胆囊切除术患者围手术期仍需使用抗生素。     

腹膜透析相关性腹膜炎的病原菌菌谱及耐药性分析

目的：分析本中心腹膜透析相关性腹膜炎（peritoneal dialysis-associated peritonitis,PDAP）的致病菌谱及其对常用抗生素的耐药性情况，为治疗提供依据。方法：回顾性总结分析本中心2010年01月—2019年12月的持续不卧床腹膜透析（CAPD）236例患者中发生PDAP的腹膜透析透出液病原学培养及药敏结果。结果：331例次PDAP腹膜透析透出液标本，病原菌培养阳性193例次，培养阴性138例次，阳性率58.51%，其中革兰氏阳性菌（G+菌）136株（70.47%），以表皮葡萄球菌、溶血葡萄球菌、金黄色葡萄球菌为主；革兰氏阴性菌（G-菌）42株（21.76%），以大肠埃希菌、铜绿假单胞菌、肺炎克雷伯菌为主；真菌15株（7.77%）。G+菌对青霉素、头孢唑林钠、左氧氟沙星的耐药率分别为70.16%、62.50%、38.28%，对万古霉素、利奈唑胺、替考拉宁敏感率分别为99.22%、99.15%、98.65%。G-菌对头孢曲松、哌拉西林、头孢噻肟的耐药率分别为28.57%、29.03%、25.00%；对莫西沙星、哌拉西林/他唑巴坦、美罗培南敏感率分别为1...     

Histochemical and contractile properties of striated muscles of urethra and levator ani of dogs and sheep

AIMS: To understand their possible importance in long- and short-term control of continence, some properties of the striated muscles of the urethra and pelvic floor (levator ani) of dogs and sheep were investigated, especially fiber types and contractile characteristics. MATERIALS AND METHODS: Striated muscles of urethra and levator ani of 29 male and 6 female dogs and 11 male and 6 female sheep were removed and cut into strips. Some strips were frozen and stained for ATPase at pH 9.4 and 4.3 for fiber typing; others were set up in an organ bath to study contractile responses to nerve stimulation. RESULTS: All muscles contained both type I (slow) and type II fibers, ranging from 97% type II in female greyhound urethra to 60% in female sheep levator ani. For each muscle, there were fewer type II muscles in sheep than in dog. The diameters of the urethral fibers were about 60% of the levator ani in dogs and 34% in sheep. Contraction of the urethral muscle was faster than for levator ani and declined to about 80% of the peak, 500 msec after the beginning of stimulation at 20 Hz. The levator ani contraction rose to a steady level as long as stimulation continued. CONCLUSIONS: Both the levator ani and urethral striated muscles contain slow and fast fiber types. The levator ani muscles are capable of sustained contraction with rapid onset which will produce long-term closure of the urethra. The circular urethral muscle contraction was faster but less well maintained.     

Incorporation and release of85Sr and14C-proline-hydroxyproline in mineral and collagen of bone and incisor teeth of growing rats

The extent to which exchange and reutilization processes of mineral tracers affect skeletal mineral accretion and resorption measurements was evaluated by comparing the rates of appearance and disappearance of⁸⁵Sr and¹⁴C-proline-hydroxyproline in bones and teeth in growing rats for 12 days following simultaneous parenteral injection of these tracers. Expressions for the relative rates of collagen synthesis and breakdown, which unlike mineral metabolism are considered not to be complicated by exchange phenomena, were based on¹⁴C-proline conversion to¹⁴C-hydroxyproline; the specific activity of the latter was determined. Both the mineral and the collagen specific activities reflected the rates and patterns of growth of the samples assayed; rapid growth and a short interval of time between formation and resorption of tissue in themetaphyseal bone which contains the cartilagineous growth plate, slow growth and an interval of time between formation and resorption of tissue indiaphyseal bone and incisor teeth which is longer than the 12 days of the experiment. However, in metaphyseal bone the specific activity collagen/mineral ratio dropped by one half during the 4–12 day interval in contrast to diaphyseal bone and incisor teeth in which no change in this ratio was observed during this period of time. The data indicate that collagen in the metaphyseal growth zone is removed by resorption before it has become fully mineralized, and that exchange is a relatively unimportant factor in the long term kinetics of bone mineral.

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Zusammenfassung Das Ausmaß, bis zu welchem Austausch- und Wiederverwendungsprozesse der mineralen Tracer die Messungen des mineralen Skelett-Auf- und Abbaues beeinflussen können, wurde ausgewertet; zu diesem Zweck wurde die Geschwindigkeit des Auftretens und Verschwindens von⁸⁵Sr und von¹⁴C-Prolin-Hydroxyprolin in Knochen und Zähnen von wachsenden Ratten während der 12 auf die simultane parenterale Injektion dieser Tracer folgenden Tage verglichen.Der Ausdruck für die relative Geschwindigkeit des Kollagen-Auf- und Abbaues, bei welchem im Gegensatz zum Mineralmetabolismus kein Mitwirken des Austauschphänomens vermutet wird, basiert auf der Umwandlung von¹⁴C-Prolin zu¹⁴C-Hydroxyprolin; die spezifische Aktivität des letzteren wurde bestimmt.Aus der spezifischen Aktivität des Minerals sowie jener des Kollagens konnten die Geschwindigkeit und die Art des Wachstums der untersuchten Proben ersehen werden, d.h.schnelles Wachstum und ein kurzes Zeitintervall zwischen Bildung und Resorption des Gewebes imKnochen der Metaphyse, die auch die knorpelige Wachstumsplatte enthält, und andererseitslangsames Wachstum und längeres Zeitintervall (länger als die 12 Tage des Experimentes) zwischen Bildung und Resorption des Gewebes imKnochen der Diaphyse und in den Schneidezähnen. Immerhin fiel die spezifische Aktivität des Kollagen/Mineral-Anteils im Knochen der Metaphyse während dem 4–12tägigen Zeitintervall auf die Hälfte, im Gegensatz zum Knochen der Diaphyse und der Schneidezähne, bei welchen während dieser Zeitspanne kein Unterschied in diesem Verhältnis beobachtet wurde.Diese Ergebnisse zeigen, daß Kollagen in der Wachstumszone der Metaphyse durch Resorption verschwindet, bevor es ganz mineralisiert ist, und daß der Austausch ein relativ unwichtiger Faktor in der Kinetik auf lange Sicht des Knochenminerals ist.

     

Instrumented ligamentotaxis and stabilization of compression and burst fractures of dorsolumbar and mid-lumbar spines

Background:

Controversy continues regarding the best treatment for compression and burst fractures. The axial distraction reduction utilizing the technique employing the long straight rod or curved short rod without derotation to reduce fracture are practised together with short segment posterolateral fusion (PLF). Effects of the early postoperative mobilization without posterolateral fusion on reduction maintenance and fracture consolidation were not evaluated so far. The present prospective study is designed to assess the effectiveness of i) reduction and restoration of sagittal alignment, ii) no posterolateral fusion on the reduced, fractured vertebral body and injured disc, iii) fracture consolidation and iv) the fate of the unfused cephalad and caudal injured motion segments of the fractured vertebra.

Materials and Methods:

The study includes 15 Denis burst and two Denis type D compression fractures between T₁₂ and L₃. The lordotic distraction technique was used for ligamentotaxis utilizing the contoured short rods and pedicle screw fixator. Three vertebrae including the fractured one were fixed. The patients after surgery were braced for ten weeks with activity restriction for 2-4 weeks. The patients were evaluated for change in vertebral body height, sagittal curve, reduction of retropulsion, improvement in neural deficit. The unfused motion segments, residual postoperative pain and bone and metal failure were also evaluated.

Results:

The preoperative and postreduction percentile vertebral heights at, zero (immediate postoperative), at three, six and 12 months followup were 62.4, 94.8, 94.6, 94.5 and 94.5%, respectively. The percentages of the intracanal fragment retropulsion at preoperative, and postoperative at zero, 3, 6 and 12 months followup were 59.0, 36.2,, 36.0, 32.3, and 13.6% respectively.The preoperative and postreduction percentile loss of the canal dimension and at zero, three, six and 12 months were 52.1, 45.0, 44.0, 41.0 and 29% respectively suggesting that the under-reduced fragment was being resorbed gradually by a remodeling process. The mean initial kyphosis of 33° became mean 2° immediately after reduction and mean 3° at the final followup. The fractured vertebral bodies consolidated in an average period of ten weeks (range 8-14 weeks). The restored disc heights were relatively well maintained throughout the observation period. All paraparetic patients recovered neurologically. There were no postoperative complications.

Conclusion:

Instrument-aided ligamentotaxis for compression and burst fractures utilizing the short contoured rod derotation technique and the instrumented stabilization of the fractured spine are found to be effective procedures which contribute to the fractured vertebral body consolidation without recollapse and maintain the motion segment function.     

Principles and Practice of Hemofiltration and Hemodiafiltration

There is growing interest in the convective dialysis therapies, hemofiltration (HF) and hemodiafiltration (HDF). Both require dialysis membranes which are highly permeable to solutes as well as fluid, and in both cases large volumes of ultrafiltration are the condition for convective transport. In HDF the convection is combined with diffusion, and as a consequence, maximum clearance over the entire molecular weight spectrum is achieved. Optimal forms of HDF provide urea clearance 10–15% higher than the corresponding diffusive mode. The larger the solute, the greater is the impact of convection, and β₂-microglobulin (β₂m) levels may be up to 70% reduced. Traditional postdilution HF provides high clearance of medium sized and large molecules. Satisfactory clearance of small solutes requires blood flows in excess of 500 ml/min. With access to practically unlimited volumes of substitution solution through on-line ultrafiltration, predilution HF can now be used. This increases the clearance of small solutes to an acceptable range. For HDF as well as HF, large patient populations consistently treated for longer periods of time are needed to make valid outcome comparisons with other therapies.     

Recognition and management of phaeochromocytoma and paraganglioma

Phaeochromocytomas and paragangliomas (PPGL) are catecholamine-secreting neuroendocrine tumours arising from the chromaffin cells in the adrenal medulla. These tumours may be identified incidentally, as part of a work-up for multiple endocrine neoplasia or following haemodynamic surges during unrelated procedures. Advances in perioperative management and improved management of intraoperative haemodynamic instability have significantly reduced surgical mortality from around 40% to less than 3%. Surgery is the definitive treatment in most cases and laparoscopic resection where possible is associated with improved outcomes. Anaesthetic management of PPGL cases represents a unique haemodynamic challenge both before and after tumour resection. In this article we describe the physiology of these tumours, their diagnosis, preoperative optimization methods, intraoperative anaesthetic management and management of postoperative complications.     

骨折不愈合与延迟愈合的成因与治疗

目的探讨骨折不愈合与延迟愈合的成因、报肯治疗的方法与设果。方法对1990年7月～2004年12月间收治的107例骨折不愈台、54例骨折延迟愈合2例先天性胫骨骨不连进行回顾性研究，分析原因，随访治疗结果。18例延迟愈合行保守治疗，本组其他145例行手术治疗，结果除2例先天性胫骨骨不连外，其余161例的成因中均有医源性因素。10例失去随访，153例平均随访17（6-28）个月，骨折均获骨性连接，愈合时间平均10（6-14）个月，肢体功能恢复良好，结论医源性技术缺陷是骨折不愈合与延迟愈合的主要原因，针对各种不同因素进行合理治疗可获得满意效果。     

Physiology and pharmacology of nausea and vomiting

Nausea and vomiting are both very unpleasant experiences. The physiology is poorly understood; however, understanding what we do know is key to tailoring a preventative or therapeutic antiemetic regime. There are two key sites in the central nervous system implicated in the organization of the vomiting reflex: the vomiting centre and the chemoreceptor trigger zone. There are five key neurotransmitters involved in afferent feedback to these areas. These are histamine (H₁ receptors), dopamine (D₂), serotonin (5-HT₃), acetyl choline (muscarinic) and neurokinin (substance P). Postoperative nausea and vomiting will occur in around one-third of elective patients who have no prophylaxis. This can result in many detrimental effects including patient dissatisfaction, unplanned admission and prolonged recovery. It is therefore essential that clinicians understand how they can prevent and treat nausea and vomiting using either a single agent or a combination of antiemetics to target relevant receptors. Commonly used drugs include antihistamines, dopamine antagonists, serotonin antagonists and steroids. More novel agents are being developed such as aprepitant, a neurokinin receptor antagonist, palonosetron, a 5HT₃ receptor antagonist and nabilone, a synthetic cannabinoid.     

Physiology and pharmacology of nausea and vomiting

Nausea and vomiting are both very unpleasant experiences. The physiology is poorly understood; however, understanding what we do know is key to tailoring a preventative or therapeutic antiemetic regime. There are two key sites in the central nervous system implicated in the organization of the vomiting reflex: the vomiting centre and the chemoreceptor trigger zone. There are five key neurotransmitters involved in afferent feedback to these areas. These are histamine (H₁ receptors), dopamine (D₂), serotonin (5-HT₃), acetyl choline (muscarinic) and neurokinin (substance P). Postoperative nausea and vomiting will occur in around one-third of elective patients who have no prophylaxis. This can result in many detrimental effects including patient dissatisfaction, unplanned admission and prolonged recovery. It is therefore essential that clinicians understand how they can prevent and treat nausea and vomiting using either a single agent or a combination of antiemetics to target relevant receptors. Commonly used drugs include antihistamines, dopamine antagonists, serotonin antagonists and steroids. More novel agents are being developed such as aprepitant, a neurokinin receptor antagonist, palonosetron, a 5HT₃ receptor antagonist, and nabilone, a synthetic cannabinoid.