Tromethamine

氨丁三醇
  • 文章类型: Journal Article
    背景:肌肉骨骼疾病是缺勤的重要原因。临床实践指南建议使用非甾体抗炎药(NSAIDs)治疗I-II级宫颈扭伤。已经使用了硫胺素+吡哆醇+氰钴胺维生素的组合,单独和与NSAIDs联合使用,肌肉骨骼疾病的疼痛和炎症。
    目的:本研究的目的是证明右酮洛芬的镇痛协同作用,和维生素硫胺素+吡哆醇+氰钴胺的组合在固定剂量组合(FDC)中用于治疗由I-II级宫颈扭伤引起的急性疼痛。
    方法:我们进行了多中心,prospective,随机化,双盲,IIIb期临床研究比较两个治疗组:(1)右酮洛芬25毫克/维生素B(硫胺素100毫克,吡哆醇50mg和氰钴胺0.50mg)在FDC(两种或更多种活性成分组合在一个单一的剂型)与(2)右酮洛芬25mg单药治疗(单一药物治疗特定的疾病),口服一个胶囊或片剂,每8小时7天。最终意味着,平均变化,和疼痛感知的百分比变化(使用视觉模拟评分[VAS]测量)与基线进行比较。P值<0.05被认为是统计学上显著的。使用SPSS软件进行分析,v.29.0.
    结果:与单药治疗相比,从FDC治疗的第三天开始观察到疼痛强度的统计学显着降低(-3.1±-1.5和-2.6±-1.1cm,分别)使用VAS(p=0.011)测量。关于残疾程度,使用NorthwickPark颈部疼痛问卷(NPQ),在最终测量中观察到统计学差异(7.5%,四分位数间距[IQR]2.5,10.5;vs.7.9%,IQR5.0,13.8;p=0.028)。使用FDC时报告的不良事件比例较低。
    结论:右酮洛芬/硫胺素+吡哆醇+氰钴胺维生素的FDC与右酮洛芬单药治疗I-II级宫颈扭伤患者的疼痛相比,显示出更好的疗效和更好的安全性。
    背景:NCT05001555,注册于2021年7月29日(https://clinicaltrials.gov/study/NCT05001555)。
    BACKGROUND: Musculoskeletal disorders are an important cause of work absence. Clinical practice guidelines recommend nonsteroidal anti-inflammatory drugs (NSAIDs) for grade I-II cervical sprains. The combination of thiamine + pyridoxine + cyanocobalamin vitamins has been used, alone and in combination with NSAIDs, for pain and inflammation in musculoskeletal disorders.
    OBJECTIVE: The objective of this study was to demonstrate the analgesic synergy of dexketoprofen, and the combination of vitamins thiamine + pyridoxine + cyanocobalamin in a fixed-dose combination (FDC) for the treatment of acute pain caused by grade I-II cervical sprains.
    METHODS: We conducted a multicentre, prospective, randomized, double-blind, phase IIIb clinical study comparing two treatment groups: (1) dexketoprofen 25 mg/vitamin B (thiamine 100 mg, pyridoxine 50 mg and cyanocobalamin 0.50 mg) in an FDC (two or more active ingredients combined in a single dosage form) versus (2) dexketoprofen 25 mg monotherapy (single drug to treat a particular disease), one capsule or tablet orally, every 8 h for 7 days. Final mean, average change, and percentage change in pain perception (measured using a visual analogue scale [VAS]) were compared with baseline between groups. A p value < 0.05 was considered statistically significant. Analyses were conducted using SPSS software, v.29.0.
    RESULTS: A statistically significant reduction in pain intensity was observed from the third day of treatment with the FDC compared with monotherapy (- 3.1 ± - 1.5 and - 2.6 ± - 1.1 cm, respectively) measured using the VAS (p = 0.011). Regarding the degree of disability, using the Northwick Park Neck Pain Questionnaire (NPQ), statistical difference was observed for the final measurement (7.5%, interquartile range [IQR] 2.5, 10.5; vs. 7.9%, IQR 5.0, 13.8; p = 0.028). A lower proportion of adverse events was reported when using the FDC.
    CONCLUSIONS: The FDC of dexketoprofen/thiamine + pyridoxine + cyanocobalamin vitamins demonstrated superior efficacy and a better safety profile compared with dexketoprofen monotherapy for pain treatment in patients with grade I-II cervical sprains.
    BACKGROUND: NCT05001555, registered 29 July 2021 ( https://clinicaltrials.gov/study/NCT05001555 ).
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  • 文章类型: Journal Article
    滴定量热计的校准是一个持续存在的问题,特别是对于反应容器体积<10mL的量热计,其中电校准加热器位于量热容器外部。因此,必须使用具有已知焓变化的化学反应来准确地校准这些热量计。这项工作建议使用滴定到过量氢氧化钠(NaOH)或过量三(羟甲基)氨基甲烷(TRIS)溶液中的邻苯二甲酸钾(KHP)标准溶液作为标准反应,以确定相关变量的集体准确性。确定反应的摩尔焓变化。KHP易于获得高纯度,易于制备具有准确已知浓度的溶液,在溶液中稳定,不损害与常见的污染物,如大气中的二氧化碳副反应,和非腐蚀性的材料使用的热量计的建设。根据KHPpKa的可靠文献数据,从0到60°C计算这些反应的摩尔焓变化,TRIS质子化的摩尔焓变化,和水电离的摩尔焓变化。在几个热量计中测试了使用这些反应作为焓标准的可行性;50mLCSC4300,185μLNanoITC,1.4毫升VP-ITC,和具有1mL反应容器的TAMIII。50毫升CSC4300的结果是用电加热器精确校准的,验证了拟议反应的摩尔焓变化计算标准值的准确性。
    Calibration of titration calorimeters is an ongoing problem, particularly with calorimeters with reaction vessel volumes < 10 mL in which an electrical calibration heater is positioned outside the calorimetric vessel. Consequently, a chemical reaction with a known enthalpy change must be used to accurately calibrate these calorimeters. This work proposes the use of standard solutions of potassium acid phthalate (KHP) titrated into solutions of excess sodium hydroxide (NaOH) or excess tris(hydroxymethyl)aminomethane (TRIS) as standard reactions to determine the collective accuracy of the relevant variables in a determination of the molar enthalpy change for a reaction. KHP is readily available in high purity, weighable for easy preparation of solutions with accurately known concentrations, stable in solution, not compromised by side reactions with common contaminants such as atmospheric CO2, and non-corrosive to materials used in calorimeter construction. Molar enthalpy changes for these reactions were calculated from 0 to 60 °C from reliable literature data for the pKa of KHP, the molar enthalpy change for protonation of TRIS, and the molar enthalpy change for ionization of water. The feasibility of using these reactions as enthalpic standards was tested in several calorimeters; a 50 mL CSC 4300, a 185 μL NanoITC, a 1.4 mL VP-ITC, and a TAM III with 1 mL reaction vessels. The results from the 50 mL CSC 4300, which was accurately calibrated with an electric heater, verified the accuracy of the calculated standard values for the molar enthalpy changes of the proposed reactions.
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  • 文章类型: Journal Article
    背景:尽管存在多种治疗选择,包括固定剂量组合(FDC)药物,但对急性疼痛的满意管理仍然是一个主要的医学挑战。曲马多和右酮洛芬氨丁三醇(TRAM/DKP)75/25mgFDC于2018年在亚洲推出,广泛用于治疗中度至重度急性疼痛。关于其在亚洲患者中的有效性和安全性的数据有限,因此,需要更好地了解其在临床实践中的使用模式。我们的目标是了解TRAM/DKPFDC的使用模式,其在亚洲中度至重度急性疼痛患者中的有效性和耐受性。
    方法:REKOVER是第四阶段,多国,多中心,prospective,真实世界的观察研究。共有750名术后和非手术患者(男性和女性,18-80岁)将从新加坡的13家三级医院(15家医院)招募,泰国,菲律宾和马来西亚。所有接受TRAM/DKPFDC处方并愿意参与研究的患者将被招募。每个网站的招聘时间为6个月。在第1天至第5天的治疗期间,将使用数字疼痛评定量表收集疼痛的严重程度,同时在治疗结束时使用患者总体评估量表评估对治疗的满意度。在研究期间报告的任何不良事件将被记录用于安全性分析(直到第6天)。研究数据将输入ClaimIt门户和移动应用程序(app)(ObvioHealth,美国)。所有的住院病人数据将被输入到门户网站的研究网站和门诊病人将通过应用程序完成。
    背景:该研究已获得新加坡各研究中心当地伦理委员会的批准,泰国,菲律宾和马来西亚。调查结果将通过地方和全球会议介绍传播,同行评审科学期刊和继续医学教育的出版物。
    BACKGROUND: Satisfactory management of acute pain remains a major medical challenge despite the availability of multiple therapeutic options including the fixed-dose combination (FDC) drugs. Tramadol and dexketoprofen trometamol (TRAM/DKP) 75/25 mg FDC was launched in 2018 in Asia and is widely used in the management of moderate to severe acute pain. There are limited data on its effectiveness and safety in Asian patients, and therefore, a need to better understand its usage patterns in clinical practice. We aim to understand the usage pattern of TRAM/DKP FDC, its effectiveness and tolerability in patients with moderate to severe acute pain in Asia.
    METHODS: REKOVER is a phase-IV, multicountry, multicentre, prospective, real-world observational study. A total of 750 postsurgical and non-surgical patients (male and female, aged 18-80 years) will be recruited from 13 tertiary-care hospitals (15 sites) in Singapore, Thailand, the Philippines and Malaysia. All patients prescribed with TRAM/DKP FDC and willing to participate in the study will be enrolled. The recruitment duration for each site will be 6 months. The severity of pain will be collected using Numeric Pain Rating Scale through the treatment period from day 1 to day 5, while satisfaction with the treatment will be evaluated using Patient Global Evaluation Scale at the end of treatment. Any adverse event reported during the study duration will be recorded for safety analysis (up to day 6). The study data will be entered into the ClaimIt portal and mobile application (app) (ObvioHealth, USA). All the inpatient data will be entered into the portal by the study site and for outpatient it will be done by patients through an app.
    BACKGROUND: The study has been approved by the local ethics committee from each study sites in Singapore, Thailand, the Philippines and Malaysia. Findings will be disseminated through local and global conference presentations, publications in peer-reviewed scientific journals and continuing medical education.
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  • 文章类型: Journal Article
    开发了一种反相高效液相色谱(HPLC)方法,用于同时测定右酮洛芬的潜在杂质,包括口服R-酮洛芬.在极性有机和反相模式下筛选了四个多糖柱(Lux直链淀粉-1,Lux直链淀粉-2,Lux纤维素-1和Lux纤维素-2)的分离能力之后,仅在LuxAmylose-2柱上在酸化的乙腈/水混合物中观察到适当的对映体分离。对映和化学选择性的流动相组成和温度的详细研究显示了许多意想不到的观察结果。观察到,可以通过改变温度和流动相组成来微调拆分和对映体洗脱顺序。此外,在直链淀粉型柱上使用甲醇/水混合物在反相模式下也观察到保留时间和对映选择性的滞后。这可能表明直链淀粉柱的三维结构可以通过从极性有机模式转变为反相模式而改变,影响对映分离过程。在反相模式下还观察到温度依赖性对映异构体洗脱顺序和在工作温度范围内罕见的焓/熵控制的对映异构体分离。寻找测定右酮洛芬杂质的最佳方法学条件,进行了全因子优化设计。使用优化的参数(LuxAmylose-2色谱柱,水/乙腈/乙酸50/50/0.1(v/v/v),流速为1mL/min,20°C),所有化合物之间在15分钟内实现基线分离。我们新开发的HPLC方法根据现行指南进行了验证,并在市售药物制剂上测试了其应用。根据作者的知识,这是首次报道反相模式下多糖柱的滞后行为的研究。
    A reversed-phase high-performance liquid chromatographic (HPLC) method was developed for the simultaneous determination of the potential impurities of dexketoprofen, including the distomer R-ketoprofen. After screening the separation capability of four polysaccharide columns (Lux Amylose-1, Lux Amylose-2, Lux Cellulose-1 and Lux Cellulose-2) in polar organic and in reversed-phase modes, appropriate enantioseparation was observed only on the Lux Amylose-2 column in an acidified acetonitrile/water mixture. A detailed investigation of the mobile phase composition and temperature for enantio- and chemoselectivity showed many unexpected observations. It was observed that both the resolution and the enantiomer elution order can be fine-tuned by varying the temperature and mobile phase composition. Moreover, hysteresis of the retention times and enantioselectivity was also observed in reversed-phase mode using methanol/water mixtures on amylose-type columns. This could indicate that the three-dimensional structure of the amylose column can change by transitioning from a polar organic to a reversed-phase mode, which affects the enantioseparation process. Temperature-dependent enantiomer elution order and rare enthalpic/entropic controlled enantioseparation in the operative temperature range were also observed in reversed-phase mode. To find the best methodological conditions for the determination of dexketoprofen impurities, a full factorial optimization design was performed. Using the optimized parameters (Lux Amylose-2 column with water/acetonitrile/acetic acid 50/50/0.1 (v/v/v) at a 1 mL/min flow rate at 20 °C), baseline separations were achieved between all compounds within 15 min. Our newly developed HPLC method was validated according to the current guidelines, and its application was tested on commercially available pharmaceutical formulations. According to the authors\' knowledge, this is the first study to report hysteretic behavior on polysaccharide columns in reversed-phase mode.
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  • 文章类型: Journal Article
    死后获得的附睾精子被认为是遗传物质的宝贵来源,通常会不可避免地丢失。这使得这些配子构成了保护和恢复计划的关键要素。明智的(野牛,Linnaeus1758)是一种在自然栖息地灭绝后在动物园中幸存下来的物种。这导致整个种群的遗传范围缩小,目前只有12个祖先。目前,明智的保护计划旨在通过建立种质资源库来保护遗传多样性。这项研究的目的是全面表征形态学,明智的附睾精子的形态计量学和功能,并基于Tris缓冲液和鸡蛋黄评估其在延伸剂中冷冻保存的有效性。从一个个体获得的精子总数中位数为1985.0×106(62.5×106-7452.0×106)。这些配子的特征是中位数:40.0%(0.5-70.0%)主观运动性,69.8%(32.5-90.0%)的存活率和54.3%(10.5-83.3%)的正常形态。精子头的中位尺寸为5.0μm(3.5-6.7μm)宽度,8.5μm(6.4-11.3μm)的长度和36.9μm2(23.7-48.6μm2)的表面积。获得的配子的可行种群的特征是完整精子膜的中值为53.2%(4.5-80.3%),完整顶体的50.8(26.0-76.6%),0.4%(0-98.7%)的碎片染色质,5.9%(0.0-88.8%)的细胞具有高线粒体电位,42.1%(8.3-63.7%)没有脂质过氧化。冷冻/解冻配子的可行种群的特征为中值:完整精子膜的18.4%(2.4-57.9%),完整顶体的35.1(11.9-56.7%),0.07%(0-89.2%)的碎片染色质,12.8%(0.0-49.7%)的细胞具有高线粒体电位,16.3%(2.2-53.6%)没有脂质过氧化。由于材料来自相对大量的野生个体,这里提出的研究有助于描述某些物种标准,以评估明智的附睾精子。对这些配子的冷冻保存效果证明了使用基于Tris缓冲液并添加鸡蛋蛋黄的补充剂是合理的。从保存有价值的遗传物质及其在ART中的应用的角度来看,所获得的效果是令人满意的。
    Epididymal spermatozoa obtained post mortem are considered a valuable source of genetic material which is often irrevocably lost. This makes these gametes constitute a key element in protection and restitution programs. The wisent (Bison bonasus, Linnaeus 1758) is a species that survived in zoos after extinction from its natural habitat. This resulted in a narrowing of the genetic pool of the whole population, which is at present derived from only 12 ancestors. Currently, wisent protection programs are aimed at preserving the genetic diversity by establishing a germplasm bank. The objective of this study was to comprehensively characterize the morphology, morphometry and functionality of wisent epididymal spermatozoa and evaluate the effectiveness of their cryopreservation in extender based on Tris buffer and chicken egg yolk. The median total number of spermatozoa obtained from one individual was 1985.0 × 106 (62.5 × 106-7452.0 × 106). These gametes were characterized by median: 40.0% (0.5-70.0%) subjective motility, 69.8% (32.5-90.0%) viability and 54.3% (10.5-83.3%) normal morphology. The sperm head had a median size of 5.0 μm (3.5-6.7 μm) width, 8.5 μm (6.4-11.3 μm) length and 36.9 μm2 (23.7-48.6 μm2) surface area. The viable population of the obtained gametes was characterized by median values 53.2% (4.5-80.3%) of intact sperm membrane, 50.8 (26.0-76.6%) of intact acrosome, 0.4% (0-98.7%) of fragmented chromatin, 5.9% (0.0-88.8%) of cells with high mitochondrial potential and 42.1% (8.3-63.7%) without lipid peroxidation. The viable population of the frozen/thawed gametes was characterized by median values: 18.4% (2.4-57.9%) of intact sperm membrane, 35.1 (11.9-56.7%) of intact acrosome, 0.07% (0-89.2%) of fragmented chromatin, 12.8% (0.0-49.7%) of cells with high mitochondrial potential and 16.3% (2.2-53.6%) without lipid peroxidation. Due to the material originating from a relatively large number of wild individuals, the research presented here contributed to the description of certain species standards for the assessment of wisent epididymal spermatozoa. The presented effect of cryopreservation on these gametes justifies the use of an extender based on Tris buffer with the addition of chicken egg yolk. The obtained effects are satisfactory from the point of view of preserving valuable genetic material and their use in ART.
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  • 文章类型: Randomized Controlled Trial
    背景:磷霉素作为细菌性尿路感染(BUTI)的降压疗法是一种潜在的有吸引力的选择,但是可用的数据很少。我们的目的是比较磷霉素氨丁胺醇和其他口服药物作为降压治疗因MDR大肠杆菌(MDR-Ec)引起的BUTI患者的有效性和安全性。
    方法:纳入FOREST试验(比较2014年6月至2018年12月在22家西班牙医院中由MDR-Ec引起的BUTI的IV磷霉素与头孢曲松或美罗培南)的参与者,这些参与者被降低到口服磷霉素(3gq48h)或其他药物。主要终点是治疗结束后5-7天的临床和微生物治疗(CMC)。使用逻辑回归进行多变量分析,以估计口服降压与磷霉素与CMC校正混杂因素的相关性。
    结果:总体而言,61例患者改用口服磷霉素氨丁三醇,47例改用其他药物(头孢呋辛酯,28;阿莫西林/克拉维酸和甲氧苄啶/磺胺甲恶唑,每个7;环丙沙星,5)包括在内。用磷霉素氨丁三醇治疗的患者48/61(78.7%)和用其他药物治疗的患者38/47(80.9%)达到CMC(差异,-2.2;95%CI:-17.5至13.1;P=0.38)。亚组分析提供了类似的结果。9/61(15.0%)和2/47(4.3%)患者出现复发,分别(P=0.03)。CMC的校正OR为1.11(95%CI:0.42-3.29,P=0.75)。没有观察到不良事件的相关差异。
    结论:磷霉素氨丁胺醇可能是一种合理的降压治疗方案,用于MDR-Ec导致的BUTI患者,但更高的复发率需要进一步评估。
    Fosfomycin is a potentially attractive option as step-down therapy for bacteraemic urinary tract infections (BUTI), but available data are scarce. Our objective was to compare the effectiveness and safety of fosfomycin trometamol and other oral drugs as step-down therapy in patients with BUTI due to MDR Escherichia coli (MDR-Ec).
    Participants in the FOREST trial (comparing IV fosfomycin with ceftriaxone or meropenem for BUTI caused by MDR-Ec in 22 Spanish hospitals from June 2014 to December 2018) who were stepped-down to oral fosfomycin (3 g q48h) or other drugs were included. The primary endpoint was clinical and microbiological cure (CMC) 5-7 days after finalization of treatment. A multivariate analysis was performed using logistic regression to estimate the association of oral step-down with fosfomycin with CMC adjusted for confounders.
    Overall, 61 patients switched to oral fosfomycin trometamol and 47 to other drugs (cefuroxime axetil, 28; amoxicillin/clavulanic acid and trimethoprim/sulfamethoxazole, 7 each; ciprofloxacin, 5) were included. CMC was reached by 48/61 patients (78.7%) treated with fosfomycin trometamol and 38/47 (80.9%) with other drugs (difference, -2.2; 95% CI: -17.5 to 13.1; P = 0.38). Subgroup analyses provided similar results. Relapses occurred in 9/61 (15.0%) and 2/47 (4.3%) of patients, respectively (P = 0.03). The adjusted OR for CMC was 1.11 (95% CI: 0.42-3.29, P = 0.75). No relevant differences in adverse events were seen.
    Fosfomycin trometamol might be a reasonable option as step-down therapy in patients with BUTI due to MDR-Ec but the higher rate of relapses would need further assessment.
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  • 文章类型: Randomized Controlled Trial
    背景:本研究的目的是评估单剂量右酮洛芬静脉给药预防性镇痛对双颌手术术后疼痛和减轻肿胀的影响。
    方法:作者设计了一个前瞻性的,随机化,和双盲队列研究。患有III类错牙合的患者被随机分为两组。治疗组于切口前30分钟静脉注射右酮洛芬氨丁三醇50mg,安慰剂组在切开前30分钟静脉注射无菌盐水。主要预测变量为治疗组。主要结果是疼痛,肿胀和24小时阿片类药物的摄入量。术后疼痛采用曲马多自控镇痛。其他变量是人口统计学和手术相关参数。采用视觉模拟评分法评估术后疼痛。3dMD面部系统(3dMD,美国)用于测量术后肿胀。数据采用两个独立样本t检验和MannWhitneyU检验进行分析。
    结果:研究样本由30例患者组成,平均年龄为20,63岁,21例为女性。与安慰剂组相比,提前服用右酮洛芬使术后曲马多的消耗量减少了25.9%,VAS评分有统计学意义的下降(p<0.05)。两组之间在肿胀方面没有统计学上的显着差异(p>0.05)。
    结论:预防性静脉注射右酮洛芬可在术后24小时内提供足够的镇痛效果,并减少正颌手术中阿片类药物的消耗。
    BACKGROUND: The purpose of this study was to evaluate the effect of a single-dose intravenous dexketoprofen administration for preventive analgesia on postoperative pain and reducing swelling in double jaw surgery.
    METHODS: The authors designed a prospective, randomized, and double-blind cohort study. Patients who have Class III malocclusion were randomly divided in two groups. 50 mg intravenous dexketoprofen trometamol were administrated 30 minutes before incision in treatment group, while intravenous sterile saline was administrated 30 minutes before incision in placebo group. The primary predictor variable was treatment group. Primary outcomes were pain, swelling and 24-hour opioid intake. Patient- controlled analgesia with tramadol was given for management of postoperative pain. Other variables were demographic and operation related parameters. Visual analogue scale was used to evaluate postoperative pain. 3dMD Face System (3dMD, USA) was used to measure postoperative swelling. Data were analysed using two independent samples t test and Mann Whitney U test.
    RESULTS: The study sample was composed of 30 patients with a mean age of 20,63 years and 21 were female. Preemptive dexketoprofen administration decreased postoperative tramadol consumption by 25.9% compared to placebo group, and there was a statistically significant decrease in VAS scores (p<0,05). There was no statistically significant difference between the groups in terms of swelling (p>0,05).
    CONCLUSIONS: Preventive administration of intravenous dexketoprofen provides adequate analgesic effect in the postoperative 24-hour period and reduces opioid consumption in orthognathic surgery.
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  • 文章类型: Journal Article
    高分辨率膜蛋白结构对于基本了解各种细胞过程的分子基础和药物发现至关重要。去污剂广泛用于从膜中提取跨膜蛋白并将其维持在功能状态以用于下游表征。由于封装在常规洗涤剂中的膜蛋白的长期稳定性有限,需要开发新的试剂来促进膜蛋白结构研究。在目前的研究中,我们设计并合成了带有三(羟甲基)氨基甲烷接头的三嗪基三葡糖苷(TTG),用于溶解和稳定膜蛋白。当评估这些葡糖苷去污剂的四种膜蛋白包括两种G蛋白偶联受体时,相对于两种麦芽糖苷洗涤剂[DDM(正十二烷基-β-d-麦芽糖苷)和LMNG(月桂基麦芽糖新戊二醇)],包括TTG-C10和TTG-C11的一些TTG表现出明显增强的膜蛋白稳定性行为。这是TTG的显著特征,因为葡糖苷洗涤剂在稳定膜蛋白方面倾向于劣于麦芽糖苷洗涤剂。TTG对膜蛋白稳定性的有利行为可能是由于亲脂性基团的高疏水性,亲水亲油平衡的最佳范围,和不存在顺反异构现象。
    High-resolution membrane protein structures are essential for a fundamental understanding of the molecular basis of diverse cellular processes and for drug discovery. Detergents are widely used to extract membrane-spanning proteins from membranes and maintain them in a functional state for downstream characterization. Due to limited long-term stability of membrane proteins encapsulated in conventional detergents, development of novel agents is required to facilitate membrane protein structural study. In the current study, we designed and synthesized tris(hydroxymethyl)aminomethane linker-bearing triazine-based triglucosides (TTGs) for solubilization and stabilization of membrane proteins. When these glucoside detergents were evaluated for four membrane proteins including two G protein-coupled receptors, a few TTGs including TTG-C10 and TTG-C11 displayed markedly enhanced behaviors toward membrane protein stability relative to two maltoside detergents [DDM (n-dodecyl-β-d-maltoside) and LMNG (lauryl maltose neopentyl glycol)]. This is a notable feature of the TTGs as glucoside detergents tend to be inferior to maltoside detergents at stabilizing membrane proteins. The favorable behavior of the TTGs for membrane protein stability is likely due to the high hydrophobicity of the lipophilic groups, an optimal range of hydrophilic-lipophilic balance, and the absence of cis-trans isomerism.
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  • 文章类型: Journal Article
    丝氨酸棕榈酰转移酶(SPT)催化鞘脂生物合成中的第一个反应:L-丝氨酸(L-Ser)和棕榈酰-CoA的脱羧缩合形成3-酮二氢鞘氨醇。已分离出多活鞘杆菌属的SPT,并以2.3µA的分辨率确定了其与L-Ser复合的晶体结构(PDB条目3a2b)。然而,晶体的质量不足以判断辅因子分子的构象和酶活性位点氨基酸残基侧链的取向。通过修订纯化程序以及优化结晶程序和结晶后处理条件,可以改善晶体质量。这里,SPT与三(羟甲基)氨基甲烷(Tris)络合的晶体结构,缓冲组件,在1.65的分辨率下确定。蛋白质在20°C结晶,并从晶体中收集衍射数据,分辨率为1.65。晶体属于四方空间群P41212,晶胞参数a=b=61.32,c=208.57。晶体结构分析显示,辅因子吡哆醛5'-磷酸(PLP)的磷酸基团部分中的C4-C5-C5A-O4P(77°)和C5-C5A-O4P-P(-143°)扭转角度比先前报道的晶体结构中观察到的更合理(14°和151°,分别)。此外,清晰的电子密度显示PLP和庞大的人工配体Tris之间的希夫碱连接,表明该酶的活性位点腔具有出色的灵活性。这些发现为进一步研究该酶的底物识别和催化的详细机制开辟了可能性。
    Serine palmitoyltransferase (SPT) catalyses the first reaction in sphingolipid biosynthesis: the decarboxylative condensation of L-serine (L-Ser) and palmitoyl-CoA to form 3-ketodihydrosphingosine. SPT from Sphingobacterium multivorum has been isolated and its crystal structure in complex with L-Ser has been determined at 2.3 Å resolution (PDB entry 3a2b). However, the quality of the crystal was not good enough to judge the conformation of the cofactor molecule and the orientations of the side chains of the amino-acid residues in the enzyme active site. The crystal quality was improved by revision of the purification procedure and by optimization of both the crystallization procedure and the post-crystallization treatment conditions. Here, the crystal structure of SPT complexed with tris(hydroxymethyl)aminomethane (Tris), a buffer component, was determined at 1.65 Å resolution. The protein crystallized at 20°C and diffraction data were collected from the crystals to a resolution of 1.65 Å. The crystal belonged to the tetragonal space group P41212, with unit-cell parameters a = b = 61.32, c = 208.57 Å. Analysis of the crystal structure revealed C4-C5-C5A-O4P (77°) and C5-C5A-O4P-P (-143°) torsion angles in the phosphate-group moiety of the cofactor pyridoxal 5\'-phosphate (PLP) that are more reasonable than those observed in the previously reported crystal structure (14° and 151°, respectively). Furthermore, the clear electron density showing a Schiff-base linkage between PLP and the bulky artificial ligand Tris indicated exceptional flexibility of the active-site cavity of this enzyme. These findings open up the possibility for further study of the detailed mechanisms of substrate recognition and catalysis by this enzyme.
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  • 文章类型: Journal Article
    在囊性纤维化(CF)中,囊性纤维化跨膜传导调节因子(CFTR)介导的Cl-和HCO3-跨上皮分泌的丧失使气道表面液体(ASL)酸化。酸性ASL改变了两个关键的宿主防御机制:快速ASL细菌杀伤和粘膜纤毛运输(MCT)。雾化氨丁三醇(Tham)可增加ASL的pH值,并恢复ASL快速杀死CF猪细菌的能力。在CF猪中,由于异常粘液导致微盘突然反冲,吹入的微盘的清除被中断。雾化还原剂以破坏连接粘蛋白的二硫键可改善MCT。这里,我们有兴趣通过雾化Tham来恢复CF中的MCT,pH值为8.4的缓冲液。因为Tham对血清是高渗的,我们使用酸化制剂作为对照。我们通过连续胸部计算机断层扫描跟踪单个钽微盘的尾部运动来测量MCT。碱性Tham将微盘清除率提高到非CF猪的范围内。它也部分逆转了MCT缺陷,包括减少的微盘反冲和经过的时间,直到它们在CF猪气道中的乙酰甲胆碱刺激后开始移动。这种影响不是由于高渗性,因为用酸化的Tham或高渗盐水看不到。这一发现表明酸性ASL损害CFMCT,并表明吸入Tham的ASLpH碱化可能会改善CF气道疾病。
    In cystic fibrosis (CF), the loss of cystic fibrosis transmembrane conductance regulator (CFTR) mediated Cl-  and HCO3 -  secretion across the epithelium acidifies the airway surface liquid (ASL). Acidic ASL alters two key host defense mechanisms: Rapid ASL bacterial killing and mucociliary transport (MCT). Aerosolized tromethamine (Tham) increases ASL pH and restores the ability of ASL to rapidly kill bacteria in CF pigs. In CF pigs, clearance of insufflated microdisks is interrupted due to abnormal mucus causing microdisks to abruptly recoil. Aerosolizing a reducing agent to break disulfide bonds that link mucins improves MCT. Here, we are interested in restoring MCT in CF by aerosolizing Tham, a buffer with a pH of 8.4. Because Tham is hypertonic to serum, we use an acidified formulation as a control. We measure MCT by tracking the caudal movement of individual tantalum microdisks with serial chest computed tomography scans. Alkaline Tham improves microdisk clearance to within the range of that seen in non-CF pigs. It also partially reverses MCT defects, including reduced microdisk recoil and elapse time until they start moving after methacholine stimulation in CF pig airways. The effect is not due to hypertonicity, as it is not seen with acidified Tham or hypertonic saline. This finding indicates acidic ASL impairs CF MCT and suggests that alkalinization of ASL pH with inhaled Tham may improve CF airway disease.
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