laboratory methods

实验室方法
  • 文章类型: Journal Article
    脊髓性肌萎缩症(SMA)是一种遗传性神经肌肉疾病,可引起脊髓运动神经元的变性。最近的研究表明,在症状前阶段的治疗效果更高。本系统综述综合了截至2023年11月在17个国家/地区发表的37项SMA新生儿筛查研究(和3项概述)的结果,以了解所使用的方法;测试准确性性能;和时间,物流和筛选的可行性。所有研究都筛选了SMN1外显子7的纯合缺失。大多数(28项研究)使用RT-PCR作为干血斑(DBS)的初始测试,而9项研究也报道了针对筛查阳性病例的DBS的二级测试。通过一系列方法将在DBS上测试为阳性的婴儿转介进行确认测试。观察到的SMA出生患病率从4000分之一到20,000分之一不等。大多数研究报告没有假阴性或假阳性病例(因此具有100%的灵敏度和特异性)。五项研究报告了一个或两个假阴性病例(总共六个病例;三个复合杂合子和三个由于系统错误),尽管由于缺乏对阴性结果的随访,一些假阴性可能被遗漏了。11项研究报告了假阳性病例,一些是杂合携带者或可能与肝素使用有关。测试和治疗的时间因研究而异。总之,在过去5年中,有几个国家采用多种方法实施了新生儿SMA筛查.实施考虑因素包括及时进行初始和验证性测试的过程,筛查和神经肌肉中心之间的伙伴关系,并及时开始治疗。
    Spinal muscular atrophy (SMA) is a genetic neuromuscular disorder causing the degeneration of motor neurons in the spinal cord. Recent studies suggest greater effectiveness of treatment in the presymptomatic stage. This systematic review synthesises findings from 37 studies (and 3 overviews) of newborn screening for SMA published up to November 2023 across 17 countries to understand the methodologies used; test accuracy performance; and timing, logistics and feasibility of screening. All studies screened for the homozygous deletion of SMN1 exon 7. Most (28 studies) used RT-PCR as the initial test on dried blood spots (DBSs), while nine studies also reported second-tier tests on DBSs for screen-positive cases. Babies testing positive on DBSs were referred for confirmatory testing via a range of methods. Observed SMA birth prevalence ranged from 1 in 4000 to 1 in 20,000. Most studies reported no false-negative or false-positive cases (therefore had a sensitivity and specificity of 100%). Five studies reported either one or two false-negative cases each (total of six cases; three compound heterozygotes and three due to system errors), although some false-negatives may have been missed due to lack of follow-up of negative results. Eleven studies reported false-positive cases, some being heterozygous carriers or potentially related to heparin use. Time to testing and treatment varied between studies. In conclusion, several countries have implemented newborn screening for SMA in the last 5 years using a variety of methods. Implementation considerations include processes for timely initial and confirmatory testing, partnerships between screening and neuromuscular centres, and timely treatment initiation.
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  • 文章类型: Journal Article
    本文综述了妊娠红细胞(RBC)同种免疫的危险因素和实验室检测。红细胞同种免疫是一个重要的医学问题,可导致胎儿和新生儿的溶血病(HDFN),导致新生儿发病和死亡。目前的HDFN预防仅针对恒河猴D(RhD)同种免疫,没有有效的措施来防止其他红细胞抗原组的同种免疫。几个因素可以增加怀孕期间发生红细胞同种免疫的风险,包括母胎出血,红细胞和母体遗传状态,和以前的输血。识别这些风险因素对于执行适当的管理策略以最大程度地降低HDFN的风险至关重要。该综述还讨论了妊娠管理的实验室方法和概述。该论文强调了确定和管理妊娠红细胞同种免疫风险因素的重要性,以最大程度地降低HDFN的风险并改善新生儿结局。
    This review paper provides an overview of the risk factors and laboratory testing for red blood cell (RBC) alloimmunization in pregnancy. RBC alloimmunization is a significant medical issue that can cause haemolytic disease of the fetus and newborn (HDFN), leading to neonatal morbidity and mortality. Current HDFN prophylaxis targets only Rhesus D (RhD) alloimmunization, with no effective measures to prevent alloimmunization to other RBC antigen groups. Several factors can increase the risk of developing RBC alloimmunization during pregnancy, including fetomaternal haemorrhage, RBC and maternal genetic status, and previous transfusions. Identifying these risk factors is essential to execute the appropriate management strategies to minimize the risk of HDFN. The review also discusses the laboratory methods and overview of pregnancy management. The paper highlights the importance of identifying and managing the risk factors for RBC alloimmunization in pregnancy to minimize the risk of HDFN and improve neonatal outcomes.
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  • 背景:天然产物具有光学活性,具有不寻常的结构特征或特定的立体选择性,主要包括螺环系统或季碳原子。用于天然产物纯化的昂贵且耗时的方法,特别是具有生物活性的天然产物,鼓励化学家在实验室合成这些化合物。由于它们在药物发现和化学生物学中的重要作用,天然产物已成为合成有机化学的主要领域。今天可用的大多数药用成分是源自自然资源的治疗剂,比如植物,草药,和其他天然产品。
    方法:使用ScienceDirect的三个数据库编译材料,PubMed,谷歌学者。对于这项研究,只有英文出版物根据其标题进行了评估,摘要,和全文。
    结果:从天然产物中开发生物活性化合物和药物仍然具有挑战性,尽管最近取得了进展。一个主要的挑战不是是否可以合成目标,而是如何有效和实际地合成目标。大自然有能力以微妙但有效的方式创造分子。一种方便的方法是模仿微生物天然产物的生物发生,植物,或合成天然产物的动物。受到自然界中发生的机制的启发,合成策略有助于实验室合成具有复杂结构的天然化合物。
    结论:在这篇综述中,我们详细阐述了自2008年以来进行的天然产品的最新合成,并使用生物启发方法提供了该研究领域的最新概述(涵盖2008-2022年),包括Diels-Alder二聚化,光环加成,环化,以及氧化和自由基反应,这将为仿生反应提供容易的前体。本研究提出了合成生物活性骨骼产物的统一方法。
    BACKGROUND: Natural products have optical activities with unusual structural characteristics or specific stereoselectivity, mostly including spiro-ring systems or quaternary carbon atoms. Expensive and time-consuming methods for natural product purification, especially natural products with bioactive properties, have encouraged chemists to synthesize those compounds in laboratories. Due to their significant role in drug discovery and chemical biology, natural products have become a major area of synthetic organic chemistry. Most medicinal ingredients available today are healing agents derived from natural resources, such as plants, herbs, and other natural products.
    METHODS: Materials were compiled using the three databases of ScienceDirect, PubMed, and Google Scholar. For this study, only English-language publications have been evaluated based on their titles, abstracts, and full texts.
    RESULTS: Developing bioactive compounds and drugs from natural products has remained challenging despite recent advances. A major challenge is not whether a target can be synthesized but how to do so efficiently and practically. Nature has the ability to create molecules in a delicate but effective manner. A convenient method is to imitate the biogenesis of natural products from microbes, plants, or animals for synthesizing natural products. Inspired by the mechanisms occurring in the nature, synthetic strategies facilitate laboratory synthesis of natural compounds with complicated structures.
    CONCLUSIONS: In this review, we have elaborated on the recent syntheses of natural products conducted since 2008 and provided an updated outline of this area of research (Covering 2008-2022) using bioinspired methods, including Diels-Alder dimerization, photocycloaddition, cyclization, and oxidative and radical reactions, which will provide an easy access to precursors for biomimetic reactions. This study presents a unified method for synthesizing bioactive skeletal products.
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  • 文章类型: Journal Article
    结核病的诊断,尤其是肺外结核的诊断,在临床实践中仍然面临挑战。这有几个原因。基于结核分枝杆菌(Mtb)检测的方法灵敏度不够,基于Mtb特异性免疫反应检测的方法不能总是区分活动性疾病和潜伏感染,Mtb感染的一些血清学标记物的特异性不足以区分结核病和其他炎症性疾病。基于流式细胞术等技术的新工具,质谱,高通量测序,而人工智能有可能解决这一困境。这篇综述的目的是提供当前优化经典诊断方法的最新概述。以及新的分子和其他方法,对Mtb感染患者进行准确诊断。
    Diagnosis of tuberculosis, and especially the diagnosis of extrapulmonary tuberculosis, still faces challenges in clinical practice. There are several reasons for this. Methods based on the detection of Mycobacterium tuberculosis (Mtb) are insufficiently sensitive, methods based on the detection of Mtb-specific immune responses cannot always differentiate active disease from latent infection, and some of the serological markers of infection with Mtb are insufficiently specific to differentiate tuberculosis from other inflammatory diseases. New tools based on technologies such as flow cytometry, mass spectrometry, high-throughput sequencing, and artificial intelligence have the potential to solve this dilemma. The aim of this review was to provide an updated overview of current efforts to optimize classical diagnostic methods, as well as new molecular and other methodologies, for accurate diagnosis of patients with Mtb infection.
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  • 文章类型: Journal Article
    Sickle cell disease (SCD) and other hemoglobinopathies are a major health concern with a high burden of disease worldwide. Since the implementation of newborn screening (NBS) for SCD and other hemoglobinopathies in several regions of the world, technical progress of laboratory methods was achieved. This short review aims to summarize the current practice of classical laboratory methods for the detection of SCD and other hemoglobinopathies. This includes the newborn screening technologies of high-performance liquid chromatography (HPLC), capillary electrophoresis (CE), and isoelectric focusing (IEF).
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  • 文章类型: Journal Article
    The prevalence of construction and demolition (C&D) waste and the concurrent demand for construction aggregate presents the opportunity to recycle C&D waste materials as substitutes for virgin aggregate. Commonly, recycled concrete aggregate (RCA) is used as base course in pavement construction. Environmentally responsible applications of RCA must consider the high pH leachate and trace element leaching risks reported in the literature. This review presents the methodology, results, and limitations of existing laboratory and field investigations of RCA leachate chemistry. Long-term highway field studies of RCA leachate illustrate that an initially high leachate pH approaches neutral within approximately one to two years of construction. Conversely, laboratory investigations of RCA leachate pH using batch reactor leaching tests and column leaching tests measure consistently high leachate pH (pH > 10). The discrepancies between field and laboratory measurements of RCA leachate pH suggest that the current laboratory methodology inadequately describes leachate conditions in the field. The authors recommend that future laboratory investigations consider intermittent wetting and drying cycles, eliminate particle abrasion, employ relevant contact times, and consider additional environmental processes that reduce leachate pH such as soil acidity and carbonation.
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  • 文章类型: Comparative Study
    这是使用干血斑点(DBS)和微型管(MT)HIV采样试剂盒作为在线性传播感染(STI)邮政测试服务的一部分的比较审查。英格兰最近看到基于互联网和邮政(eHealth)STI服务的增加。扩大患者的可及性和测试,成本影响和缩小艾滋病毒未诊断的边缘是驱动因素。
    2017年,在从MT过渡到DBS时,从在线邮政STI套件请求服务的数据进行了审查。我们比较了STI邮政试剂盒和HIV血液样本的回报率,以及DBS和MT试剂盒的成功处理/分析率。描述性统计被应用于参与者特征,用Pearson的χ2或Fisher精确检验来证明统计学差异。我们还描述并计算了两种套件类型的“请求与结果之比”(RRR)。RRR定义为产生一个成功分析结果所需的在线工具包请求数。
    从2017年6月13日至2017年9月22日,审查了来自英格兰西北部地区的550份STI邮政工具包请求(275MT,275DBS)。两组之间的基线特征具有可比性(63%的女性,90%的英国白人和86%的异性恋者,平均年龄为26岁)。DBS的成功处理率为98.8%c.f.MT的55.7%(p<0.001)。MT的RRR为2.96,c.f.DBS为1.70。MTc.f.中HIV假阳性率为5.4%。在DBS中没有。
    这种比较分析表明,在这种社区环境中,与MT相比,使用邮政HIVDBS试剂盒可显著改善RRR.最大的因素是由于血液体积不足而未分析的大量MT样品。MT样品中意外的假阳性结果水平需要在更大的研究中确认。
    This is a comparative review between using dried blood spot (DBS) and mini-tube (MT) HIV sampling kits as part of an online sexually transmitted infection (STI) postal testing service. England has recently seen increases in internet-based and postal (eHealth) STI services. Expanding accessibility and testing for patients, cost implications and narrowing the HIV undiagnosed margin are drivers for this.
    In 2017, data were reviewed from an online postal STI kit requesting service at a time of transitioning from MT to DBS. We compared the STI postal kit and HIV blood sample return rates, and the successful processing/analysis rates of the DBS and MT kits. Descriptive statistics were applied to participant characteristics, with Pearson\'s χ2 or Fisher exact test used to demonstrate statistical differences. We also describe and calculate a \'request-to-result ratio\' (RRR) for both kit types. The RRR is defined as the number of online kit requests required to produce one successfully analysed result.
    550 STI postal kit requests from a North-West of England region were reviewed from 13 June 2017 to 22 September 2017 (275 MT, 275 DBS). Baseline characteristics between the two groups were comparable (63% woman, 90% white British and 86% heterosexual with a median age of 26 years). The successful processing rate for the DBS was 98.8% c.f. 55.7% for the MT (p<0.001). The RRR for MT was 2.96, c.f. 1.70 for DBS. There was a 5.4% false positive HIV rate in the MT c.f. none in the DBS.
    This comparative analysis suggests that in this community setting, the use of postal HIV DBS kits resulted in a significantly improved RRR compared with MT. The biggest factor was the large number of MT samples not analysed due to inadequate blood volumes. The unexpected level of false positive results in the MT samples needs confirming in larger studies.
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  • 文章类型: Evaluation Study
    Bacterial infection after hardware implantation in orthopedic surgery is a devastating issue as it often necessitates increased hospital costs and stays, multiple revision surgeries, and prolonged use of antibiotics. Because of the nature of hardware implantation into the body, these infections are commonly in the form of attached biofilms. The current literature on a range of methodologies to study clinically explanted infected orthopedic hardware, with potential biofilm, in the laboratory setting is limited. General methods include traditional and advanced culturing techniques, microscopy imaging techniques, and techniques that manipulate genetic material. The future of diagnostic techniques for infected implants, innovative hardware design, and treatment solutions for patients all depend on the successful evaluation and characterization of clinical samples in the laboratory setting. This review provides an overview of current methods to study biofilms associated with orthopedic infections and insight into future directions in the field.
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  • 文章类型: Journal Article
    CD34抗原在造血干细胞和祖细胞上表达。已经开发了许多策略,可以从骨髓中选择和纯化CD34()细胞,外周血,和脐带血。移植研究充分证明,在重新输注选定的CD34()细胞后,可以实现快速持久的植入。最近,可以在离体培养系统中产生造血祖细胞的广泛增殖的技术已经变得可用。最流行的方法涉及补充有一系列细胞因子的简单液体悬浮培养系统。扩张的程度,的确,产生的细胞类型会受到培养条件的显著影响,如细胞因子的选择,文化的持续时间,起始细胞浓度,和培养容器的类型。尽管有许多实验室调查,很少有使用离体扩增细胞的临床试验。尽管已经证明离体培养细胞的输注具有良好的耐受性,但没有相关的毒性,迄今为止,还没有证据表明这些培养系统能够维持足够数量的造血细胞长期再生,以确保清髓治疗后的持久移植.显然,主要目标是确定培养条件,将产生真正的干细胞扩增。
    The CD34 antigen is expressed on haemopoietic stem and progenitor cells. A number of strategies have been developed which allow the selection and purification of CD34(+) cells from bone marrow, peripheral blood, and umbilical cord blood. Transplantation studies have amply demonstrated that rapid and durable engraftment can be achieved following reinfusion of selected CD34(+) cells. More recently, techniques have become available which can produce extensive proliferation of haemopoietic progenitor cells in ex vivo culture systems. The most popular method involves a simple liquid suspension culture system supplemented with a range of cytokines. The degree of expansion and, indeed, the types of cells produced can be significantly influenced by culture conditions like the choice of cytokines, duration of culture, starting cell concentration, and type of culture vessel. Despite many laboratory investigations, there have been few clinical trials using ex vivo expanded cells. Although it has been shown that infusion of ex vivo cultured cells is well tolerated with no associated toxicity, there is no evidence to date that these culture systems sustain sufficient numbers of haemopoietic long-term repopulating cells to secure durable engraftment following myeloablative therapy. Clearly, the major goal is to define culture conditions which will produce true stem cell expansion.
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  • 文章类型: Journal Article
    背景:实验室范式通常用于研究人体能量摄入。然而,参与者认为他们的饮食行为被测量的程度可能会影响能量摄入,这是一个很少被考虑的方法学因素.
    目的:我们的主要目的是研究现有证据,证明在实验室环境中,提高观察意识对能量摄入的影响。
    方法:我们系统地回顾了实验室研究,这些研究允许对提高观察意识对能量摄入的影响进行实验检查。从这些实验研究中,我们使用逆方差荟萃分析组合了效应估计,计算意识增强和控制条件之间能量摄入的标准化平均差(SMD),以及定性合成的这种影响的潜在调节剂。
    结果:九项研究,提供22个比较,有资格列入。这些研究主要对年轻女性进行了抽样,并检查了能量密集的休闲食品的能量摄入量。有证据表明,与对照条件相比,观察意识增强与能量摄入减少有关(随机效应SMD:0.45;95%CI:0.25,0.66;P<0.0001)。我们发现几乎没有证据表明用于提高意识的实验操作可以调节整体效果。
    结论:迄今为止的现有证据表明,在实验室环境中,提高对观察的认识会减少能量摄入。这些发现表明,实验室研究应尝试将参与者意识到自己的饮食行为正在被测量的程度降至最低。
    BACKGROUND: Laboratory paradigms are commonly used to study human energy intake. However, the extent to which participants believe their eating behavior is being measured may affect energy intake and is a methodologic factor that has received little consideration.
    OBJECTIVE: Our main objective was to examine available evidence for the effect that heightened awareness of observation has on energy intake in a laboratory setting.
    METHODS: We systematically reviewed laboratory studies that allowed for experimental examination of the effect that heightened awareness of observation has on energy intake. From these experimental studies we combined effect estimates using inverse variance meta-analysis, calculating the standardized mean difference (SMD) in energy intake between heightened-awareness and control conditions and qualitatively synthesized potential moderators of this effect.
    RESULTS: Nine studies, providing 22 comparisons, were eligible for inclusion. These studies largely sampled young women and examined the energy intake of energy-dense snack foods. Evidence indicated that heightened awareness of observation was associated with reduced energy intake when compared with the control condition (random-effects SMD: 0.45; 95% CI: 0.25, 0.66; P < 0.0001). We found little evidence that the type of experimental manipulation used to heighten awareness moderated the overall effect.
    CONCLUSIONS: The available evidence to date suggests that heightened awareness of observation reduces energy intake in a laboratory setting. These findings suggest that laboratory studies should attempt to minimize the degree to which participants are aware that their eating behavior is being measured.
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