磷酸化p38MAPK在实验性自身免疫性脑脊髓炎轴索损伤中的作用

目的 观察p38MAPK在实验性自身免疫性脑脊髓炎(EAE )中的活化及其与早期神经元轴索损伤的关系和变化规律,以及p38MAPK阻滞剂SB203580对轴索损伤的调节作用.方法 使用SJL雌性小鼠建立EAE模型,分别对模型组、SB203580组和对照组各时间点取脑和脊髓,行HE和Luxol Fast Blue(LFB)染色,并行磷酸化p38MAPK抗体染色;对相邻脑组织切片同时行淀粉样前体蛋白(APP)免疫组化检测.用图像分析系统对脑白质病灶内神经元胞浆阳性信号数目、覆盖面积及阳性信号平均密度值进行测量.结果 PLP肽段免疫的小鼠发病具有缓解-复发的特点,局部白质区域出现脱髓鞘改变.与模型组比较,SB203580组改变较轻,符合其行为学观测结果,且小鼠的体重增加明显高于模型组( P<0.01).除对照组,其余各组在各时间点均有APP蛋白表达.与模型组相比,SB203580组干预后APP蛋白表达较轻,阳性细胞数目与强度均明显下降( P<0.01);磷酸化p38MAPK在EAE小鼠免疫后第7天就有明显表达.与模型组相比,SB203580组p38MAPK表达较轻,阳性数目与强度均明显下降( P<0.01).结论 p38MAPK阻滞剂SB203580不仅能够抑制EAE中p38MAPK活化,而且可以有效下调EAE轴索损伤的标志性指标APP的表达;p38MAPK可能参与了EAE的轴索损伤过程.     

从小胶质细胞活化通路探讨化疗诱导大鼠神经病理性疼痛的发生机制

目的:研究脊髓小胶质细胞活化通路在化疗药物诱导的神经病理性疼痛中的作用。方法:大鼠鞘内置管并筛选出痛阈值合格的SD大鼠36只,采用随机配伍的方法分为3组:对照组、模型组、米诺环素组。用隔日腹腔注射长春新碱(125μg/kg)的方法建立化疗药物诱导的神经病理性疼痛动物模型,米诺环素组从建立化疗痛模型前1天起每日鞘内注射工具药米诺环素(100μg/rat,10μL),其他各组同步注射生理盐水。分别用Electronic von Frey测痛仪和热刺痛仪测定大鼠机械痛阈值及热痛阈值,免疫荧光法检测脊髓背角小胶质细胞特异性活化标志物Iba1的表达,Western Blot法检测脊髓CX3CR1蛋白、p-p38MAPK蛋白表达。结果:与对照组相比,模型组大鼠机械痛阈值和热痛阈值显著降低(P<0.05或P<0.01),脊髓背角Iba1蛋白、脊髓CX3CR1蛋白、p-p38MAPK蛋白表达显著升高(P<0.01);与模型组相比,米诺环素组大鼠机械痛阈值和热痛阈值相对升高(P<0.05),脊髓背角Iba1蛋白、脊髓CX3CR1蛋白、p-p38MAPK蛋白表达显著降低(P<0.05或P<0.01)。结论:脊髓小胶质细胞活化通路可能参与了化疗药物诱导的神经病理性疼痛的发生和发展。     

米诺环素治疗实验性自身免疫性脑脊髓炎的初步研究

目的探讨米诺环素对实验性自身免疫性脑脊髓炎(EAE)的治疗作用。方法以豚鼠全脊髓匀浆为抗原,免疫Wistar大鼠建立急性EAE模型。免疫后,米诺环素治疗组大鼠每天给予米诺环素50 mg/kg灌胃治疗,对照组和EAE组大鼠每天给予10 ml/kg的生理盐水灌胃,同时对各组大鼠的临床症状、脑部病理改变及外周血T细胞相关细胞因子IFN-γ、IL-4进行观察,评估米诺环素的治疗效果。结果米诺环素治疗组大鼠临床症状减轻,脑部特异性淋巴细胞浸润减少,IFN-γ表达降低。结论米诺环素治疗大鼠EAE有较为明显的效果,为治疗人的多发性硬化提供有益的借鉴。     

羟考酮超前镇痛对腹部创伤大鼠疼痛行为及脊髓p38MAPK表达的影响

【目的】探讨羟考酮超前镇痛对腹部手术创伤大鼠疼痛行为的影响及对大鼠脊髓p38丝裂原活化蛋白激酶（p38MAPK）表达的影响。【方法】成年SD大鼠随机分为三组,空白对照组（Ⅰ组,n=12）：静注生理盐水1mL;腹部手术组（Ⅱ组,n=12）：行剖腹探查手术;羟考酮超前镇痛组（Ⅲ组,n=12）：术前30min静注盐酸羟考酮0．5mg／kg再手术。观察术毕1h,2h大鼠行为学改变,测定机械刺激痛阈值（MWT）。免疫组化测定术后2h脊髓p38MAPK表达情况。【结果】①Ⅱ组大鼠术后1h,2h的MWT值均显著低于Ⅲ组（P〈0．01）②Ⅱ组脊髓p38MAPK表达显著高于Ⅲ纽（P〈0．01）。【结论】术前30min静注羟考酮对腹部手术大鼠有明显超前镇痛作用,其镇痛作用可能与抑制大鼠脊髓p38MAPK的表达有关。     

米诺环素对实验性自身免疫性脑脊髓炎大鼠轴索损伤的影响

目的:探讨米诺环素对实验性自身免疫性脑脊髓炎(EAE)大鼠轴索损伤的影响。方法:以豚鼠全脊髓匀浆(GPSCH)免疫大鼠建立EAE模型。治疗组给予米诺环素而对照组和模型组给予生理盐水灌胃;免疫组化检测β-淀粉样前体蛋白(β-App)的表达。结果:细胞数,脊髓模型组高于治疗组而对照组最低(P<0.05),大脑和脑干模型组高于对照组(P<0.05);平均光密度,脊髓模型组高于另两组(P<0.05),大脑和脑干模型组高于治疗组而对照组最低(P<0.05)。结论:米诺环素可以抑制β-App的表达,可能对EAE轴索损伤有一定保护作用。     

身痛逐瘀汤对腰椎退变模型大鼠纤维环细胞p38MAPK信号通路的影响

目的:观察身痛逐瘀汤对腰椎退变模型大鼠纤维环细胞p38MAPK信号通路的影响。方法:24只雄性SD大鼠按随机数字表法分为身痛逐瘀汤组、模型组、假手术组,每组8只。身痛逐瘀汤组、模型组采用纤维环穿刺法建立大鼠腰椎退变模型,造模1个月后行中药灌胃治疗,身痛逐瘀汤组予身痛逐瘀汤灌胃,模型组及假手术组予等量生理盐水灌胃,每日1次,连续4周。治疗结束后处死大鼠取出椎间盘,采用免疫组化法观察纤维环细胞p-p38、p38和NF-κB蛋白表达,Western Blot法测定p-p38、p38和NF-κB蛋白含量。结果:身痛逐瘀汤组p-p38、NF-κB蛋白表达较模型组明显减少(P0.05),模型组较假手术组明显增加(P0.01),假手术组p-p38、NF-κB蛋白少或无表达;3组间p38蛋白表达差异无统计学差异(P0.05)。结论:身痛逐瘀汤可延缓椎间盘退变,其机制可能与下调p-p38和NF-κB蛋白表达,抑制p38MAPK信号通路激活有关。     

脉冲电磁场对椎间盘退行性病变大鼠A2A腺苷受体及p38 MAPK信号通路的影响

目的 观察脉冲电磁场（PEMF）对椎间盘退行性病变（IDD）大鼠A2A腺苷受体（A2AR）及p38 MAPK信号通路的影响。 方法 采用随机数字表法将40只SD大鼠分为对照组、IDD模型组（简称模型组）、PEMF组和PEMF联合CGS-21680治疗组（简称观察组）。将模型组、PEMF组及观察组大鼠制成IDD动物模型，PEMF组于制模后给予PEMF干预，观察组则给予PEMF干预并注射A2AR激动剂CGS-21680。于造模8周后采用番红O-快绿染色评估各组大鼠椎间盘病理改变，同时检测各组大鼠椎间盘A2AR、环磷酸腺苷（cAMP）、蛋白激酶A(PKA)、半胱氨酸天冬氨酸蛋白水解酶-3（Caspase-3）、Ⅱ型胶原（Col-Ⅱ）、基质金属蛋白酶-3（MMP3）表达水平。 结果 模型组大鼠髓核组织皱缩，纤维成分及软骨细胞增多，观察组大鼠髓核形态基本趋于正常，纤维环完整无破裂。模型组椎间盘组织A2AR蛋白表达及mRNA水平均高于对照组，观察组A2AR蛋白表达及mRNA水平均显著高于其他各组（P<0.05）。PEMF组和观察组椎间盘cAMP含量及PKA mRNA表达均较模型组增高，且观察组与模型组间差异具有统计学意义（P<0.05）。模型组大鼠椎间盘p38 MAPK、p-p38 MAPK含量及p-p38 MAPK/p38 MAPK比值均显著高于对照组（P<0.05），PEMF组和观察组p38 MAPK、p-p38 MAPK蛋白含量及p-p38 MAPK/p38 MAPK比值均有不同程度降低，且观察组上述指标数值均显著低于模型组（P<0.05），p-p38 MAPK蛋白含量及p-p38 MAPK/p38 MAPK比值亦显著低于PEMF组（P<0.05）。模型组大鼠Caspase-3蛋白含量及mRNA表达均显著高于对照组，PEMF组及观察组上述指标含量均较模型组明显降低（P<0.05）。模型组大鼠MMP3含量较对照组显著升高，Col-Ⅱ含量则明显下降；PEMF组、观察组MMP3含量均较模型组降低，Col-Ⅱ表达均较模型组增高，并且观察组上述指标含量与模型组间差异均具有统计学意义（P<0.05）。 结论 炎性因子刺激能活化p38 MAPK信号通路并诱导细胞凋亡，这也是促进IDD大鼠病变的重要原因之一。PEMF联合A2AR激动剂干预能激活A2AR/cAMP/PKA信号通路，进而抑制p38 MAPK磷酸化，减少髓核细胞凋亡，缓解IDD损伤。     

N-乙酰半胱氨酸对高氧肺损伤保护机制与p38丝裂素活化蛋白激酶途径的相关性研究

目的 观察p38丝裂素活化蛋白激酶(p38MAPK)信号途径在高氧肺损伤中的表达,探讨N-乙酰半胱氨酸(NAC)在高氧肺损伤中的保护作用及机制.方法 将30只幼年Wistar大鼠按随机数字表法分为空气对照组(A组)、高氧暴露组(B组)、高氧+NAC干预组(C组)、高氧+p38MAPK特异性抑制剂(SB203580)干预组(D组)、高氧+NAC+SB203580联合干预组(E组),每组6只.实验7 d后,光镜下观察肺组织病理改变,并行肺损伤评分;测定肺湿/干重(W/D)比值、支气管肺泡灌洗液(BALF)中总蛋白(TP)含量、肺通透系数;采用免疫组化法检测磷酸化p38MAPK(p-p38MAPK)在肺组织中的分布;用蛋白质免疫印迹法检测p-p38MAPK蛋白含量.结果 与A组比较,高氧各组均有不同程度的肺损伤,但药物干预各组(C、D、E组)肺损伤均较B组有所减轻.免疫组化显示,高氧各组p-p38MAPK阳性表达较A组明显增强,尤高表达在炎性浸润细胞;药物干预后(C、D、E组)p-p38MAPK阳性细胞较B组明显减少.蛋白质免疫印迹法显示,B组p-p38MAPK蛋白含量明显高于A组(0.20±0.03比0.11±0.01,P<0.05);干预后C、D、E组p-p38MAPK蛋白含量低于B组(0.16±0.02、0.15±0.01、0.14±0.02比0.20±0.03,均P<0.05),但仍高于A组(均P<0.05),而C、D、E组间则无明显差异.各组肺W/D比值、BALF中TP含量、肺通透系数改变与p-p38MAPK蛋白含量变化趋势一致.结论 高氧应激可激活损伤肺组织p38MAPK活性;NAC抗氧化肺保护作用机制可能是通过下调高氧诱导p38MAPK的激活而对肺损伤起保护作用.     

缺血预处理星形胶质细胞GDNF抑制p38MAPK信号通路减轻神经元凋亡

目的研究缺血预处理星形胶质细胞分泌GDNF抑制p38MAPK信号通路发挥脑保护作用。方法原代培养神经元及星形胶质细胞,给予缺血预处理,将星形胶质细胞培养基制备成条件培养基,沉默GDNF基因的培养基作为另一种条件培养基,将神经元分为对照组、预处理组、预处理+缺血组、缺血组,应用不同条件培养基孵育神经元,流式细胞术检测神经元凋亡,Western Blot法检测神经元p38MAPK及p-p38MAPK的表达。结果预处理+缺血组和缺血组神经元凋亡率明显增高(P<0.05),加入ACM2后凋亡率较ACM1和ACM3两组均减低(P<0.05)。每组神经元的p38MAPK蛋白表达均无明显变化(P>0.05);预处理+缺血组及缺血组p-p38MAPK的蛋白表达均明显高于对照组和预处理组(P<0.05),预处理+缺血组p-p38MAPK的蛋白表达均较缺血组低(P<0.05),加入ACM2组的p-p38MAPK蛋白表达低于ACM1和ACM3两组(P<0.05)。结论缺血预处理后星形胶质细胞分泌GDNF抑制p38MAPK信号通路的激活从而减少神经元凋亡,起到脑保护作用。     

米诺环素对缺血性血管性痴呆小鼠白质损伤和少突胶质细胞丢失的影响分析

目的研究米诺环素对缺血性血管性痴呆(SIVD)小鼠白质损伤和少突胶质细胞丢失的影响。方法 60只C57BL/6小鼠随机分为假手术组、模型组、米诺环素(MNO)高剂量治疗组(H-MNO:50 mg/kg)和低剂量治疗组(LMNO:5 mg/kg),每组15只。模型组和米诺环素治疗组小鼠用手术缝合线永久性结扎右颈总动脉,假手术组只做创伤,不结扎。术后第1天米诺环素高、低剂量治疗组小鼠分别接受剂量为50 mg/kg和5 mg/kg的腹腔注射;模型组与假手术组小鼠腹腔注射等体积量的生理盐水,1次/d注射28 d。分别在治疗1 d、7 d、14 d、28 d用mNSS评分系统评估各组小鼠的神经功能;术后29 d起进行Morris水迷宫测试,记录各组小鼠逃避潜伏期、目标象限内的穿台次数和停留时间;检测结束后取小鼠的脑组织进行HE染色和免疫组化染色,分析各组小鼠脑白质区病理损伤和CX47蛋白表达阳性细胞数; TUNEL染色分析细胞凋亡情况; Western blot检测小鼠脑组织中nestin、Bcl-2、Bad和cleaved-caspase-3蛋白表达量。结果与假手术组相比,模型组mNSS评分显著增加,小鼠的神经功能和学习认知功能明显下降(P 0. 05);随着米诺环素治疗周期的延长,与模型组相比,小鼠的神经功能和学习认知功能明显得到恢复和改善,且高剂量治疗组的效果明显优于低剂量治疗组(P 0. 05)。与假手术组相比,模型组小鼠脑组织细胞水肿和坏死严重;与模型组相比,米诺环素高剂量治疗能够改善小鼠脑组织细胞水肿和坏死。与假手术组相比,模型组小鼠CX47表达的阳性细胞数、nestin蛋白和抑凋亡Bcl-2蛋白的表达量显著下降(P 0. 05),凋亡细胞比率、促凋亡蛋白Bad和cleaved-caspase-3蛋白的表达显著增高;与模型组相比,米诺环素治疗组CX47表达的阳性细胞数、nestin蛋白和抑凋亡Bcl-2蛋白的表达量显著增加,凋亡细胞比率、促凋亡蛋白Bad和cleaved-caspase-3蛋白的表达显著受到抑制,且米诺环素高剂量治疗组变化优于低剂量治疗组,差异均有统计学意义(P 0. 05)。结论高剂量的米诺环素能够通过抑制脑细胞凋亡,促进少突胶质细胞的再生改善SIVD小鼠白质损伤。     

Determination of creatine kinase isoenzyme MB activity in serum using immunological inhibition of creatine kinase M subunit activity. Activity kinetics and diagnostic significance in myocardial infarction.

This is a new method for the determination of creatine kinase isoenzyme MB activity in serum. The method uses direct activity measurement of creatine kinase B subunit activity after blocking of CK-M subunit activity by inhibiting antibodies. The test takes no longer than 15 min. The method yields an intra-serial C.V. of 2.0-12.9%, and a C.V. from day to day of 5.5%. The detection limit is 3.4 U/l creatine kinase MB. In the 95 cases with proven myocardial infarction several types of creatine kinase MB activity kinetics could be determined. The percentage of creatine kinase MB of peak CK-total is 6-25%, with a mean of 11.1%. The amount of creatine kinase MB with respect to total CK activity after reinfarction is higher than the amount after initial infarction.     

Dissociable correlates of two classes of retrieval processing in prefrontal cortex

Although substantial evidence suggests that the prefrontal cortex (PFC) implements processes that are critical for accurate episodic memory judgments, the specific roles of different PFC subregions remain unclear. Here, we used event-related functional magnetic resonance imaging to distinguish between prefrontal activity related to operations that (1) influence processing of retrieval cues based on current task demands, or (2) are involved in monitoring the outputs of retrieval. Fourteen participants studied auditory words spoken by a male or female speaker and completed memory tests in which the stimuli were unstudied foil words and studied words spoken by either the same speaker at study, or the alternate speaker. On "general" test trials, participants were to determine whether each word was studied, regardless of the voice of the speaker, whereas on "specific" test trials, participants were to additionally distinguish between studied words that were spoken in the same voice or a different voice at study. Thus, on specific test trials, participants were explicitly required to attend to voice information in order to evaluate each test item. Anterior (right BA 10), dorsolateral prefrontal (right BA 46), and inferior frontal (bilateral BA 47/12) regions were more active during specific than during general trials. Activation in anterior and dorsolateral PFC was enhanced during specific test trials even in response to unstudied items, suggesting that activation in these regions was related to the differential processing of retrieval cues in the two tasks. In contrast, differences between specific and general test trials in inferior frontal regions (bilateral BA 47/12) were seen only for studied items, suggesting a role for these regions in post-retrieval monitoring processes. Results from this study are consistent with the idea that different PFC subregions implement distinct, but complementary processes that collectively support accurate episodic memory judgments.     

俯卧位通气对高海拔地区肺复张治疗无效急性呼吸窘迫综合征患者氧合的影响

目的 探讨俯卧位通气对高海拔地区肺复张术(RM)治疗无效急性呼吸窘迫综合征(ARDS)患者的治疗作用.方法 从海拔2260m的地区医院筛选RM治疗无效的41例ARDS患者[平均氧合指数( PaO2/FiO2)较RM前升高＜20％视为RM无效],依不同病因分为肺内源性ARDS组(ARDSp组)和肺外源性ARDS组(ARDSexp组),每组再按信封法随机分为俯卧位组和仰卧位组,即ARDSp俯卧位组(11例)、ARDSp仰卧位组(9例)、ARDSexp俯卧位组(10例)、ARDSexp仰卧位组(11例).在通气前及通气1、2、3、4h监测动脉血氧分压( PaO2)、PaO2/FiO2、静态顺应性(Cst)、气道阻力(Raw)的变化.结果 通气lh时,ARDSexp俯卧位组PaO2/FiO2( mm Hg,l mm Hg=0.133 kPa)即较通气前显著升高(157.4±40.6比129.3±48.7,P＜0.05),并随通气时间延长呈持续增高趋势,4h达峰值(219.1 ±41.1);且ARDSexp俯卧位组通气3h内PaO2/FiO2较其他3组显著增高,另3组间则差异无统计学意义.ARDSp俯卧位组、ARDSexp俯卧位组通气4h时PaO2/FiO2均较相应仰卧位组显著增高(208.8±39.7比127.4±47.1,219.1±41.1比124.9±50.8,均P＜0.05).4组通气前后Cst无显著改变,各组间差异也无统计学意义.ARDSp俯卧位组通气4h时Raw(cmH2O·L-1·s-1)较通气前显著降低(6.8±1.7比10.7±1.8,P＜0.05),且明显低于其他3组;其他3组各时间点Raw组内及组间比较差异均无统计学意义.结论 俯卧位通气作为ARDS机械通气重要策略之一,可以改善RM无效高原ARDS患者的氧合,为抢救患者赢得宝贵的时间.     

Digital imaging among medical facilities

The Department of Veterans Affairs (VA) in the USA operates a network of 172 medical centres which all utilize a hospital information system (HIS) which has been developed and is currently maintained by the VA. During the past several years, an image management and communication module has been developed, installed and clinically utilized at the Washington DC and Maryland VA Medical Centres. This image management and communication system, referred to as the decentralized hospital computer program (DHCP) imaging system, is fully integrated with a commercial picture archiving and communication system (PACS). The system is utilized to capture, archive, and display all images generated within the hospital including radiology, nuclear medicine, pathology, endoscopy, bronchoscopy, and dermatology, intraoperative photographs, ECG data, and a limited number of paper documents. The ultimate goal of the project is to have all patient text and image data available at any clinical workstation to any authorized user anywhere within the network of medical centres. Clinical requirements for an imaging workstation include ease of use, rapid and reliable access to the complete set of patient information, and images which are of acceptable quality to meet the requirements of the user and the subspecialty. Patient confidentiality and data security must be safeguarded at all times. Integration of the images with the remainder of the patient's database was found to be critical to the success of the project. The experience at the Washington and Maryland facilities suggests that an imaging system that is successfully integrated with a hospital information system can provide substantial clinical and economic benefits both within and among medical centres. Clinical acceptance and utilization of the system has been excellent, particularly in diagnostic radiology where DHCP Imaging has been interfaced to a commercial PAC system. Based upon this initial experience, the VA has begun to deploy the system throughout its large network of medical centres.     

Myocardial elastography at both high temporal and spatial resolution for the detection of infarcts

Myocardial elastography is a novel method for noninvasively assessing regional myocardial function, with the advantages of high spatial and temporal resolution and high signal-to-noise ratio (SNR). In this paper, in-vivo experiments were performed in anesthetized normal and infarcted mice (one day after left anterior descending coronary artery [LAD] ligation) using a high-resolution (30 MHz) ultrasound system (Vevo 770, VisualSonics Inc., Toronto, ON, Canada). Radiofrequency (RF) signals of the left ventricle (LV) in longitudinal (long-axis) view and the associated electrocardiogram (ECG) were simultaneously acquired. Using a retrospective ECG gating technique, 2-D full field-of-view RF frames were acquired at an extremely high frame rate (8 kHz) that resulted in high-quality incremental displacement and strain estimation of the myocardium. The incremental results were further accumulated to obtain the cumulative displacements and strains. Two-dimensional and M-mode displacement images and strain images (elastograms), as well as displacement and strain profiles as a function of time, were compared between normal and infarcted mice. Incremental results clearly depicted cardiac events including LV contraction, LV relaxation and isovolumetric phases in both normal and infarcted mice, and also evidently indicated reduced motion and deformation in the infarcted myocardium. The elastograms indicated that the infarcted regions underwent thinning during systole rather than thickening, as in the normal case. The cumulative elastograms were found to have higher elastographic SNR (SNR(e)) than the incremental elastograms (e.g., 10.6 vs. 4.7 in a normal myocardium, and 6.0 vs. 2.4 in an infarcted myocardium). Finally, preliminary statistical results from nine normal (m = 9) and seven infarcted (n = 7) mice indicated the capability of the cumulative strain in differentiating infracted from normal myocardia. In conclusion, myocardial elastography could provide regional strain information at simultaneously high temporal (>/=0.125 ms) and spatial ( approximately 55 microm) resolution as well as high precision ( approximately 0.05 microm displacement). This technique was thus capable of accurately characterizing normal myocardial function throughout an entire cardiac cycle, at the same high resolution, and detecting and localizing myocardial infarction in vivo.     

Clinical Pharmacokinetics of Morphine

Morphine, the most widely used mu-opioid analgesic for acute and chronic pain, is the standard against which new analgesics are measured. A thorough understanding of the pharmacokinetics of morphine is required in order to safely and effectively use this analgesic in a wide variety of patients with different levels of organ function. A MEDLINE search was conducted to identify literature published between 1966 and January 2002 relevant to the pharmacokinetics of morphine. These publications were reviewed and the literature summarized regarding unique and clinically important elements of morphine disposition relative to its parenteral administration (including intravenous, intramuscular, subcutaneous, epidural and intrathecal administration), absorption profile (immediate release, controlled release, and sublingual/buccal, and rectal administration), distribution, and its metabolism/ excretion. Special populations, including infants, elderly, and those with renal/liver failure, have a unique morphine pharmacokinetic profile that must be taken into account in order to maximize analgesic efficacy and reduce the risk of adverse events.