高效液相色谱法及串联质谱法在苯丙酮尿症筛查诊断中的应用

目的考查了高效液相色谱(HPLC)法和串联质谱(MS/MS)法在遗传代谢性疾病苯丙酮尿症(PKU)筛查中的应用及意义。方法利用MS/MS法和HPLC法分别分析了1 860例出生3d至11岁儿童的干血滤纸片及全血标本中苯丙氨酸(Phe)、酪氨酸(Tyr)浓度及其比值。结果 MS/MS法和HPLC法Phe线性范围为26.02~101.11μmol/L和32.04~132.50μmol/L,Tyr线性范围为41.50~253.07μmol/L和32.85~111.50μmol/L,平均回收率Phe为97.36%和98.43%,Tyr为96.71%和98.99%,批内CV Phe为4.31%和3.97%,Tyr为4.09%和4.01%,批间CV Phe为5.73%和4.58%,Tyr为6.01%和5.24%。结论两种方法均能灵敏,特异的测定血中Phe和Tyr浓度,满足对PKU筛查及诊断的需要。     

超高效液相色谱快速检测万古霉素浓度方法的建立和性能评价

目的建立一种基于超高效液相色谱(UPLC)技术快速测定血清万古霉素浓度的方法并评价其性能。方法以去甲万古霉素为内标,以0.3 mol/L硫酸锌水溶液为蛋白沉淀剂,对血清样本进行前处理。色谱柱为Phenomenex Kinetex C18柱(100 mm×2.1 mm,2.6μm),流速为0.5 mL/min,检测波长为220 nm,柱温40℃。流动相A为25 mmol/L磷酸二氢钾缓冲液(pH值为2.5),流动相B为乙腈,进行梯度洗脱,并对方法的线性、准确度(加标回收率)、精密度、携带污染率、定量限和检测限等分析性能进行评价。分别采用UPLC和高效液相色谱(HPLC)测定50例患者血清万古霉素浓度,并对测定结果进行方法学比对和评价。结果UPLC测定万古霉素的线性范围为2.0~99.6μg/mL,定量限和检测限分别为1.0和0.1μg/mL。低、中、高浓度样本的平均批内变异系数(CV)分别为3.28%、2.21%、2.59%,批间CV分别为5.73%、2.75%、0.82%。低浓度(2.0μg/mL)、中浓度(19.9μg/mL)、高浓度(79.6μg/mL)加标样本的平均加标回收率分别为104.06%、99.80%、100.19%。中浓度样本的携带污染率为0.57%,高浓度样本的携带污染率为0.19%。UPLC和HPLC测定患者血清万古霉素浓度具有良好的相关性(r=0.9919)。结论建立了基于UPLC技术的万古霉素血药浓度监测方法,该方法的重现性好、快速、简便、灵敏度高、准确度高,适用于临床常规万古霉素药物浓度监测。     

高效液相色谱法同时测定血清色氨酸和犬尿氨酸浓度的方法建立及应用

目的建立一种高效液相色谱-紫外检测法同时测定血清中色氨酸(Trp)和犬尿氨酸(Kyn)浓度的方法。方法色谱柱采用Agilent Hypersil ODS(125.0mm×4.0mm,5μm),流动相为15mmol/L乙酸钠缓冲液(pH4.0)和乙腈95∶5(V/V),流速为0.8ml/min,柱温25℃,紫外检测λKyn=360nm,λTrp=278nm。结果Kyn和Trp的保留时间分别为3.3min和5.2min,线性范围分别为0.083~21.000μmol/L和2.650~678.000μmol/L,检测限分别为0.028μmol/L和0.053μmol/L,日内和日间相对标准偏差分别低于5%和10%,回收率分别为91.99%~113.89%和95.81%~118.82%。结论该方法简便、快速、特异,适合于临床检测。     

高效液相色谱法在类风湿关节炎患者血清TRP和KYN检测中的应用与临床价值

目的 探讨高效液相色谱荧光检测法(HPLC-FLD)同时测定血清色氨酸(TRP)和犬尿氨酸(KYN)对诊断类风湿关节炎(RA)的临床意义.方法 血清标本加等量5%(V/V)高氯酸溶液去除蛋白,离心取上清液20 μl,直接进样分析.色谱柱为HpemilC_8柱(300 mm×6.0 mm i.d,10 μm);流动相为0.25 mol/L醋酸锌和50 mmol/L醋酸溶液(含3%乙腈),流速为1.5 ml/min;0～10 min荧光检测器的激发波长和发射波长分别为365 nm和480 nm,10 min后激发波长和发射波长分别变换为254 nm和404 nm.同时,用该方法测定120名健康成人和110例RA患者血清TRP、KYN和TRP/KYN比值(K/T),并评价其诊断RA的敏感度、特异度和方法学效能.结果 血清标本的KYN和TRP保留时间分别为8.1和11.5 min,两者分离良好.KYN线性范围为0.098 ～19.600 μmol/L,最低检测浓度为0.04 μmol/L;回收率为90.8%～96.2%,日内变异系数为3.68%,日间变异率为4.97%.TRP的线性范围为4.9～196.0μmol/L.最低检测限为0.005 μmol/L,回收率为92.6～106.9%,13内变异系数为3.63%,日间变异系数为4.44%.在本试验的色谱条件下测定苯丙氨酸(Phe)、酪氨酸(Tyr)、犬尿喹啉酸(KYNA)、5-羟色胺(5-HT)和Cr均无干扰.RA组患者血清KYN含量和K/T比值[(2.06±0.38) μmol/L和(55.46±5.81)×10~(-3)]与健康对照组[(1.51±0.35)μmol/L和(32.54 ±9.00)×~(-3)]比较,均显著升高(U=3 251.0,t=10 741,P均为0.000),而RA组TRP含量[(38.24±5.27)μmol/L]与健康对照组[(47.52±5.79)μmol/L]比较,则显著降低(t=10.399,P=0.000).K/T比值诊断RA的敏感度、特异度分别为83.6%(92/110)、85.8%(103/120).结论 HPLC-FLD同时测定血清TRP和KYN的方法精密度、回收率、抗干扰能力、线性范围等均符合临床检测要求.K/T比值可作为RA的辅助性诊断指标.     

颗粒增强免疫透射比浊法检测血清高半胱氨酸

目的建立测定血清中高半胱氨酸(Hcy)的颗粒增强免疫透射比浊法。方法血清Hcy经S-腺苷高半胱氨酸水解酶(SAHase)与腺苷转化为S-腺苷高半胱氨酸(SAH),用抗SAH抗体与转化后SAH以及胶乳颗粒结合的SAH先后反应,根据生成免疫复合物的变化值计算出SAH浓度;依据美国CLSI标准和指南性文件,对方法进行评价。结果建立的方法检测范围为3.0～53.0μmol/L,最低检测限0.6μmol/L;批内不精密度1.00%～2.09%;日间不精密度4.69%～5.44%;方法回收率为97.3%～105.6%;Vit-C≤1 000 mg/L、胆红素≤400μmol/L、乳糜≤0.8%、Hb≤6.0 g/L对测定结果无显著性干扰;参考值为<15.5μmol/L;与高效液相色谱(HPLC)法相关性良好(r=0.994,P<0.01),测定结果无显著性差异。结论建立的方法可用于临床实验室检测血清Hcy浓度。     

血清肌酐二步酶法检测新技术研究

目的探讨二步酶法测定肌酐的实验方法。方法以肌酐酰氨基水解酶为试剂Ⅱ,以N-(2-羟基-3-磺丙基)-3,5-二甲氧基苯胺钠盐(HDAOS)和4-氨基安替比林(4-AAP)色原物作为试剂Ⅰ,建立二步酶法测定血清肌酐。通过内空白法消除内源性肌酸和改变光谱吸收方法消除脂血、溶血、黄疸干扰。采用二步酶法测定36例患者血清肌酐,并与高效液相色谱(HPLC)法和一步酶法比较;同时测定200名健康体检者血清肌酐,以建立参考范围。结果患者组肌酐二步酶法结果[(84.2±26.6)μmol/L]明显低于一步酶法[(116.6±29.6)μmol/L,t=32.12,P<0.01];与HPLC法测定结果[(83.9±26.8)μmol/L]差异无统计学意义(t=0.541 6,P>0.05),且呈良好相关性(Y二步酶法=1.042XHPLC法-0.182 1,r2=0.982 4)。二步酶法测定血清肌酐的线性范围达4 500μmol/L,平均回收率为100.8%,批内和批间变异系数(CV)分别为2.91%～4.20%和3.20%～4.60%,应用二步酶法每天测定室内质控定值血清[低(78.0μmol/L)、中(206.0μmol/L)、高(900.0μmol/L)],共测定180 d,其日间总CV分别为4.46%、5.27%、7.24%。二步酶法试剂至少能稳定180 d。健康人群血清肌酐的参考范围男性为56～132μmol/L,女性为41～109μmol/L。结论以肌酐酰氨基水解酶为试剂Ⅱ和以HDAOS、4-AAP为色原物(试剂Ⅰ)的二步酶法可以消除肌酸和脂血、溶血、黄疸血的干扰,可用于临床肌酐常规测定。     

反相高效液相色谱紫外法检测人血清尿酸

目的探讨日本临床化学会(JSCC)推荐的检测人血清尿酸(UA)的反相高效液相色谱紫外(HPLC-UV)法是否可作为候选参考方法来验证同位素稀释质谱法、评价常规方法。方法对反相HPLC-UV法进行复现并进行方法学评价。观察尿酸酶处理人血清样本后的色谱以评价其特异性;检测系列标准液的UA水平并绘制标准曲线,观察线性范围;用朗道公司质控品评价精密度;用UA标准液评价回收率;分别用有证参考物SRM 909b(Ⅰ和Ⅱ)、国家一级标准物质GBW 09176、GBW 09175、GBW 09174评价正确度,并与2008年国际临床化学与检验医学联合会(IFCC)参考实验室RELA(ring trials for reference labora-tories)结果进行比对;用改良Bland-Altman图评价5种常规检测系统与反相HPLC-UV法间的偏差。结果尿酸酶处理后UA色谱峰消失;本法的线性范围为2.08～1 785μmol/L;批内变异系数(CV)均<0.3%,批间CV均<0.4%,日间CV均<2.3%,总CV均<2.7%;平均相对回收率为96.0%～100.6%;与SRM909bⅠ和Ⅱ靶值的偏移分别为-2.5%、-2.3%;与GBW09176、GBW 09174、GBW 09175靶值的偏移分别为0.29%,-0.74%和0.06%;与参加RELA比对的另3家实验室的平均值进行比较,水平1偏移为0.35%,水平2为-0.69%;Hitachi、Beckman Coulter、Roche、Dade、Vitros常规检测系统检测人血清UA与反相HPLC-UA法的相关系数分别为0.998 9、0.996 5、0.999 2、0.999 2和0.998 7,与反相HPLC-UA法的偏差均小于5%的生物学变异。结论本法特异、简便、快速,精密度好,正确度高,与具有良好溯源的常规测定系统具有良好的相关性和一致性,可推荐作为人血清UA测定的候选参考方法。     

高效液相色谱-串联质谱法检测血清油酸及其在胰岛素抵抗中的应用

目的建立高效液相色谱-串联质谱法(HPLC-MS/MS)检测血清油酸(OA),初步评估OA在2型糖尿病(T2DM)胰岛素抵抗(IR)中的作用。方法用OA-[~(13)C_5]作为同位素内标物,OA和OA-[~(13)C_5]的离子对分别为281.3/281.3和286.3/286.3。ZORBAX SB-Aq C18反相色谱柱,流动相A为超纯水,流动相B为甲醇乙腈(1∶1,v/v),梯度洗脱,流速0.3 mL/min。根据EP15-A3文件,考察精密度和正确度、线性范围、稳定性、携带污染率等性能以评价该方法的可靠性。选取临床确诊T2DM患者109例及体检健康者100例,用HPLC-MS/MS检测血清OA,并计算胰岛素抵抗指数(HOMA-IR)评价IR,进一步分析OA与IR的关系。结果建立的检测OA的HPLC-MS/MS特异性好,在10～1 000μmol/L范围内线性关系良好,y=0.007 55x+0.004 83,r=0.997 7,定量限(LLOQ)为10μmol/L,批内不精密度(以变异系数CV表示)≤1.62%,实验室内CV≤1.73%,方法精密度较好,适合临床血清样品的测定。与健康人对照组血清OA水平(113.20±58.00)μmol/L比较,T2DM组血清OA水平(425.58±220.17)μmol/L升高,且对照组和T2DM组OA与HOMA-IR均呈正相关。以OA诊断IR的AUC为0.689,当根据约登指数确定cut-off值为235.8μmol/L时,敏感性为70.4%,特异性为63%;当OA联合FPG诊断IR时,AUC增至0.806,且与OA诊断IR的AUC比较,差异有统计学意义(P0.05)。结论建立了科学、高效定量检测血清OA浓度水平的HPLC-MS/MS,为动态监测代谢性疾病人群OA含量的变化提供了可靠的方法。     

HPLC法测定末梢血中苯丙氨酸与酪氨酸及在苯丙酮尿症中的应用

目的 建立一种简单、快速的反相高效液相色谱法测定末梢血液中的苯丙氨酸(Phe)与酪氨酸(Tyr)并用于苯丙酮尿症(PKU)的筛查.方法 末梢血标本与等量5%(v/v)高氯酸溶液混合处理去除蛋白后离心取上清液20 μl直接进样分析.用Hypersil C8色谱柱(6.0mm×300mm,10μm)分离,流动相为乙腈-水(体积比5:95),流速1.5 ml/min,紫外检测波长210 nm,室温下测定.结果 末梢血中Tyr和Phe均分离良好,保留时间分别为5.88 min和8.43 min.102例健康儿童指血Phe浓度67.7±15.4/μmol/L,Tyr浓度为62.2±13.9μmol/L,Phe/Tyr比值为1.15±0.27.32例正常新生儿足跟血Phe浓度为66.2±20.5 μmol/L,Tyr浓度为59.5±18.8/μmol/L,Phe/Tyr比值为1.12±0.24.结论 该法灵敏度高,特异性好,方法 简便快速,成本低康,适合于末梢血中Phe和Tyr的同时测定及PKU的筛查与监控.     

HPLC-UV检测法同时测定血浆色氨酸和犬尿氨酸的方法学研究

目的 建立一种同时测定血浆中Trp和Kyn浓度的HPLC-UV检测法.方法 以3-硝基酪氨酸(3-N-Tyr)为内标,采用Agilent Hypersil ODS色谱柱进行分离.流动相中醋酸缓冲液( 15 mmol/L,pH 5.5):乙腈为94∶ 6(v/v);流速为0.8 ml/min;柱温:25℃;紫外程序化检测波长:0～4 min,360 nm;4～5 min,302 nm.选取2010年9-12月重庆市九龙坡区第一人民医院15例慢性乙型肝炎患者、8例慢性肾炎患者、10例血小板减少性紫癜患者以及15名健康体检者,用该方法检测其血浆Trp、Kyn水平并计算Kyn/Tp比值;各指标在上述4组间的比较采用单因素方差分析,两两比较采用SNK法.结果 Kyn与Trp的保留时间分别为2.9 min和4.4 min,线性范围分别为0.44～18.30μmol/L和3.67～470.00 μmol/L,检测限分别为0.014 μmol/L和0.122 μmol/L.Kyn与Trp的日内变异均小于3％,日间变异均小于4％.平均回收率均在92.29％～104.40％之间.用该方法测定临床标本,健康对照组、慢性肾炎组、血小板减少性紫癜组以及慢性乙型肝炎组血浆中Kyn浓度分别为(1.59±0.28)、(2.73±0.56)、(2.69±0.44)和(1.54±0.48) μmol/L,Trp浓度分别为(59.8±10.0)、(46.1±11.7)、(58.5±8.0)和(41.4±13.1)μmol/L,Kyn/Trp比值分别为(0.027 4±0.007 5)、(0.061 6±0.0165)、(0.0467±0.0091)和(0.038 3±0.007 5),差异均有统计学意义(F值分别为23.734,8.463和20.921,P均＜0.01).结论 所建立HPLC-UV检测法可同时测定血浆中Kyn和Trp浓度,适合于临床检测.     

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.