FHIT、WWOX和MDR1基因在鼻咽癌中的表达

目的探讨FHIT、WWOX基因组在鼻咽癌患者中的表达、失活机制及MDR1基因在鼻咽癌中的表达。方法采用荧光相对定量RT-PCR法检测89例鼻咽癌患者(试验组)和61例慢性鼻黏膜炎患者(对照组)鼻咽部组织WWOX、FHIT和MDR1基因mRNA表达水平,甲基化特异性(MSP)方法及变性聚丙烯酰胺凝胶电泳分析FHIT和WWOX基因mRNA表达下调原因。结果 (1)实验组鼻咽组织中FHIT、WWOX和MDR1基因的mRNA表达量与对照组间的差异有统计学意义(P0.05);按临床分期和分化程度分层后,试验组中病情较严重者较病情轻者,分化程度低的较分化程度高者间的FHIT和WWOX基因表达量差异有统计学意义(P0.05),且FHIT和WWOX基因表达量与临床分期、分化程度呈负相关(r=-0.731,P=0.000;r=-0.816,P=0.000;r=-0.626,P=0.000;r=-0.536,P=0.001);试验组低分化者MDR1基因mRNA与高分化者间差异有统计学意义(P=0.021),且组织学类型与MDR1基因mRNA相对表达量呈负相关(r=-0.697,P=0.000);试验组的FHIT与WWOX基因的mRNA相对表达量呈正相关(r=0.540,P=0.000)。(2)试验组的FHIT和WWOX基因启动子甲基化程度明显高于对照组,差异有统计学意义(P0.05);且FHIT和WWOX的mRNA与该基因启动子甲基化程度呈正相关(r=-0.689,P=0.000;r=-0.594,P=0.000)。(3)试验组中有39例(43.8%)在FHIT基因中至少有1个位点存在杂合性缺失(LOH),在WWOX基因中42例(47.2%)至少一个位点存在LOH,明显高于对照组的3例和2例(4.9%,3.3%),差异有统计学意义(P0.05)。且FHIT和WWOX基因mRNA与该基因基因杂合性缺失呈负相关(r=-0.239,P=0.049;r=-0.364,P=0.013)。结论启动子甲基化是鼻咽癌患者WWOX和FHIT基因表达下调的主要原因,可能也是鼻咽癌的发生、发展的主要原因。MDR1基因过度表达与鼻咽癌的分化程度密切相关。     

脑梗死患者中血浆同型半胱氨酸水平对血栓调节蛋白甲基化及表达的影响

目的:探讨脑梗死患者中血浆同型半胱氨酸(Hcy)水平对血栓调节蛋白(TM)甲基化及表达的影响.方法:选择脑梗死患者80例(脑梗死组),及同期住院的非脑梗死患者60例(对照组).采集患者静脉血,提取总DNA,并对总DNA进行亚硫酸氢盐修饰.利用巢式甲基化特异性PCR(nMSP)对TM基因启动子区甲基化进行分析.测定血浆中Hcy表达水平,比较不同组别Hcy水平差异,并分析其对TM启动子区甲基化的影响.提取各组TM总RNA,比较不同甲基化总RNA的差异.测定血浆中TM表达水平,比较不同组别TM水平差异.结果:2组在高血压患者人数、血糖(GLU)、总胆固醇(TC)方面差异有统计学意义(P＜0.05).脑梗死组检出TM基因启动子区甲基化60例(75.00％),对照组检出29例(48.33％),脑梗死组比对照组有更高的TM基因启动子区甲基化检出率(=10.528,P＜0.01).2组血浆中Hcy、TM水平及TM基因mRNA的表达量有统计学差异(P＜0.01).脑梗死组TM启动子区UMe、HMe、FMe组mRNA的表达量分别比对照组减少84％、73％、34％.TM启动子区甲基化程度随着血浆中Hcy水平的升高而显著升高(r=0.68,P＜0.01),随着TM基因mRNA表达量的升高而显著降低(r=-0.72,P＜0.01).结论:脑梗死患者血浆中高Hcy水平会可能会造成TM基因启动子区甲基化程度升高,进而造成TM基因mRNA的表达量降低.此外,血浆中TM水平过高,可能是由于脑梗死患者内皮损伤引起.     

胶质瘤患者RASSF1A基因转录表达和启动子区甲基化的研究

目的 探讨RASSF1A(RAS association domain family 1A)基因mRNA表达水平和基因启动子区CpG岛甲基化程度及其与启动子甲基化的关系。方法 用半定量逆转录聚合酶链反应(RT-PCR)检测28份胶质瘤组织和4份正常脑组织中RASSF1A基因mRNA相对表达水平;用甲基化特异性PCR方法研究胶质瘤组织、正常脑组织和U251细胞株中,RASSF1A基因启动子区CpG岛甲基化状态。结果 RASSF1A mRNA在4份正常脑组织中全部表达;在脑胶质瘤中表达缺失率为21.4％(6/28),且表达量低于正常脑组织,但与患者年龄、性别、肿瘤大小、恶性程度间的差异无显著意义(P>0.05)。按病理学分类,胶质母细胞瘤与少突胶质肿瘤的差异有显著意义(P=0.011)。脑胶质瘤中RASSF1A基因启动子发生甲基化的频率为39.3％(11/28),正常脑组织和U251细胞株中,RASSF1A基因启动了未发生甲基化。11份启动子区甲基化的胶质瘤标本中,5份同时伴mRNA表达缺失(P=0.022)。结论 RASSF1A基因启动了在胶质瘤中发生异常甲基化。尽管RASSF1A mRNA在脑胶质瘤中表达缺失并不广泛,但其表达普遍下调。推测启动子区CpG岛甲基化可能是导致RASSF1A基因在胶质瘤中表达缺失或表达水平下调的一种机制。     

儿童急性淋巴细胞白血病p16基因甲基化及表达水平临床意义

目的 探讨p16基因甲基化及表达水平改变在儿童急性淋巴细胞白血病(ALL)发病机制中的作用.方法 ALL患儿76例,其中初发(uALL)患儿69例、复发(rALL)患儿7例,健康儿童28例纳入对照组.采用荧光定量聚合酶链反应(RTPCR)检测外周血淋巴细胞p16基因mRNA表达;采用基于SYBR Green的甲基化特异性定量PCR(MethySYBR PCR)检测p16基因启动子甲基化水平.结果 ALL患儿淋巴细胞p16基因启动子甲基化水平高于健康儿童,uALL患儿p16基因甲基化水平低于rALL患儿(P＜0.05);ALL患儿p16基因mRNA水平低于健康儿童,uALL患儿p16基因转录水平高于rALL患儿(P＜0.05);p16基因转录水平与其启动子甲基化水平呈负相关关系(r=-0.63,P＜0.05);首次化疗即获完缓解ALL患儿p16基因甲基化水平低于未完全缓解患儿,而p16 mRNA表达水平高于后者(P＜0.05);p16基因低甲基化或高表达水平ALL患儿巩固强化治疗平均缓解时间明显低于p16基因高甲基化或低表达患儿(P＜0.05).结论 p16基因甲基化及表达低下可能与ALL发病有关,p16基因甲基化状态及表达水平检测或可用于儿童ALL预后评估.     

Apaf-1基因启动子甲基化与抑凋亡蛋白Apollon表达在成人急性白血病发生发展中的意义

目的 探讨Apaf-1基因启动子甲基化与抑凋亡蛋白Apollon在成人急性白血病(AL)发生发展中的作用.方法 采用甲基化特异性PCR(MS-PCR)检测53例AL患者骨髓细胞基因启动子区域甲基化情况,RT-PCR方法 检测Apaf-1 mRNA表达水平.免疫细胞化学方法 检测Apollon蛋白表达情况,正常骨髓对照为10名正常人和非恶性血液病患者.结果 18例(33.9%)AL患者Apaf-1基因启动子存在异常甲基化,甲基化检测阳性患者均未检测到Apaf-1 mRNA的表达,对照组仅1份Apaf-1 mRNA表达缺失,MS-PCR检测未发现Apaf-1基因启动子的异常甲基化,AL患者Apaf-1基因甲基化阳性率高于对照组,差异有统计学意义(P＜0.05),AL患者骨髓细胞Apollon蛋白表达水平高于对照组(P＜0.05),AL患者外周血WBC＞10×109/L的患者Apaf-1基因启动子甲基化阳性率及Apollon蛋白表达水平高于WBC≤10×109/L患者,差异有统计学意义(P＜0.05),AL患者中Apaf-1基因启动子甲基化阳性率与Apollon蛋白表达呈正相关.结论 Apaf-1基因启动子的异常甲基化与抑凋亡蛋白Apollon的高表达在白血病的发生发展中可能起协同作用,共同促进了白血病的发生、发展.     

乳癌组织TSLC1基因mRNA表达及启动子甲基化状态

目的探讨乳癌组织中非小细胞肺癌抑制因子（TSLC1）基因mRNA表达及其启动子甲基化状态。方法应用实时荧光定量PCR和甲基化特异性PCR,分别检测39例人乳癌组织及对应癌旁组织中TSLC1基因mRNA表达及其启动子甲基化状态,并探讨二者之间的关系。结果乳癌组织中TSLC1mRNA的表达量是癌旁组织的0.44倍。乳癌组织及癌旁组织中TSLC1基因甲基化率分别为56.4%、10.3%,乳癌组织中TSLC1基因甲基化率明显高于相应癌旁组织（χ2=16.673,P〈0.01）。甲基化的癌组织中TSLC1mRNA的表达量是非甲基化者的0.60倍,表达TSLC1mRNA的癌组织的甲基化率为50%,不表达者为100%,两者之间差异有显著性（P=0.046）。结论 TSLC1基因异常甲基化是其在乳癌组织中表达缺失或下调的原因之一,在乳癌的发生发展中起一定作用,可能成为乳癌的早期诊断及治疗靶点基因之一。     

骨髓增生异常综合征患者p73基因启动子区域异常甲基化的研究

目的 探讨骨髓增生异常综合征(MDS)患者抑癌基因p73启动子区域甲基化情况及其在预后中的意义.方法 收集135例初诊MDS患者及13名正常志愿者骨髓细胞,用甲基化特异性PCR (MS-PCR)方法检测p73基因启动子CpG岛甲基化发生情况,并利用亚硫酸盐测序法验证MS-PCR结果;荧光定量PCR法检测p73 mRNA表达情况;利用地西他滨处理MDS患者原代细胞,观察p73基因去甲基化及p73 mRNA表达情况;结合临床资料分析p73基因异常高甲基化在MDS中的作用.结果 37.0％的MDS患者p73基因启动子呈高甲基化状态,而且高危组MDS患者(RAEB-1、RAEB-2)甲基化发生率明显高于低危组(58.8％对29.7％,P=0.002);甲基化组患者p73 mRNA表达水平显著低于非甲基化组(P=0.032);用地西他滨处理后,可见MDS原代细胞p73去甲基化,且p73mRNA表达水平增高;p73高甲基化患者无白血病生存时间(DFS)及总体生存时间(OS)低于p73非甲基化患者(P值均＜0.01).在COX模型中,p73基因甲基化状况和骨髓原始细胞水平为影响患者DFS及OS的独立预后因素.结论 p73基因启动子高甲基化在MDS患者中较常见,且提示预后不良,可能为地西他滨治疗的靶点.     

HOX11~+急性T淋巴细胞白血病RUNX2基因启动子区域CpG岛甲基化及其表达的研究

本研究检测RUNX2基因在HOX11+急性T淋巴细胞白血病(T-ALL)细胞株和T-ALL患者骨髓细胞中的甲基化状态和表达水平,探讨其表达水平与启动子区CpG岛甲基化的关系。以3株急性T淋巴细胞白血病细胞株sil-ALL、DND41和RPMI及38例T-ALL患者、29例治疗后完全缓解T-ALL患者骨髓和8例正常人骨髓为样本,采用RT-PCR检测RUNX2 mRNA表达水平,采用重硫酸盐测序法、甲基化DNA免疫沉淀技术和启动子寡核苷酸微阵列芯片分析基因启动子区CpG岛甲基化状态和基因功能。结果表明,高表达HOX11的T-ALL患者样本中会出现RUNX2基因启动子区域的甲基化。RUNX2基因启动子区域在HOX11+T-ALL的甲基化比率为78.9%,明显高于HOX11-ALL(36.8%),两组差异有统计学意义(P<0.01)。RUNX2在HOX11+的细胞株中的表达明显低于HOX11-的细胞株,RUNX2在HOX11+的T-ALL患者中的表达水平(0.581±0.257)明显低于HOX11-的T-ALL患者(0.835±0.317),并且RUNX2 mRNA的相对表达程度与HOX11 mRNA的相对表达程度成负相关(rs=-0.378,P<0.01)。RUNX2基因在T-ALL中的表达水平与其甲基化呈负相关(rs=-0.419,P<0.01)。结论:HOX11能负调控RUNX2的表达,RUNX2基因启动子甲基化是导致其在T-ALL中表达下调或基因沉默的原因,这种HOX11对RUNX2基因的抑制作用有可能就是临床上HOX11高表达T-ALL患者具有更好的无事件生存率和更长的总生存率的原因。RUNX2基因的表达和甲基化水平对判断T-ALL患者的疗效有一定意义,并有望成为一个诊断T-ALL的分子标志。     

慢性髓系白血病患者中基因SCIN表达及启动子甲基化的临床研究

目的:探讨基因SCIN表达及启动子甲基化在慢性髓系白血病(CML)患者中的临床意义。方法:应用实时定量PCR检测64例CML患者和37例对照骨髓单个核细胞SCIN的表达水平。应用实时定量甲基化特异性PCR结合亚硫酸盐测序PCR检测65例CML患者和29例对照SCIN启动子甲基化水平。结果:CML患者与对照组相比细胞SCIN表达水平明显下调(P=0.010);慢性期、加速期与急变期患者中SCIN表达下调率分别为61%、67%和75%,有增加趋势。Spearman相关性分析显示,基因SCIN表达与BCR-ABL1转录水平呈负相关(r=-0.315,P0.05)。然而,SCIN低表达组与高表达组相比较,在性别、年龄、外周血白细胞数、血红蛋白水平、血小板数量、染色体特征、CML分期及BCR-ABL1转录水平等临床参数中未见差异(P0.05)。CML患者SCIN启动子甲基化水平与对照组比较无统计学差异,且SCIN表达与启动子甲基化水平无相关性(P0.05)。结论:基因SCIN在CML患者中非甲基化依赖性表达下调,可能与BCR-ABL1融合基因致病CML有关;SCIN表达下调可能与CML进展有关。     

Fibulin-1基因启动子区域甲基化与食管癌的关系研究

目的:检测食管癌Fibulin-1基因启动子区域甲基化的情况,探讨其相关的临床意义。方法:选取黄石市中心医院2014年1月至2016年2月收治的食管鳞状细胞癌患者96例,另取同期黄石市中心医院因食管良性病变手术切除的食管组织40例作为对照。Fibulin-1基因启动子甲基化使用亚硫酸盐修饰后PCR检测。免疫组织化学检测显示Fibulin-1蛋白表达。结果:食管癌患者中Fibulin-1基因启动子甲基化阳性率为36.5%,显著高于对照组的15.0%(χ2=2.517,P=0.036)。免疫组织化学检测显示Fibulin-1基因启动子甲基化标本中Fibulin-1蛋白阳性表达率为90.2%。食管癌患者男女性别和不同年龄之间Fibulin-1基因启动子甲基化率无显著性差异(P0.05)。Ⅲ,Ⅳ临床分期患者Fibulin-1基因启动子甲基化率为43.1%,显著高于Ⅰ,Ⅱ临床分期患者的28.9%(χ~2=2.4 2 6,P=0.0 4 6)。肿瘤有淋巴结转移患者Fibulin-1基因启动子甲基化率为44.4%,显著高于无淋巴结转移患者的26.2%(χ2=2.438,P=0.041)。肿瘤中、低分化患者Fibulin-1基因启动子甲基化率为42.6%,显著高于高分化患者的25.7%(χ~2=2.431,P=0.043)。结论:Fibulin-1基因启动子在食管癌组织中高甲基化,Fibulin-1基因启动子高甲基化与食管癌的临床分期、肿瘤分化程度以及有无淋巴结转移密切相关。     

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.