Magnetic resonance microscopy versus light microscopy in human embryology teaching

A study was carried out on the application of magnetic resonance microscopy (MRM) in teaching prenatal human development. Human embryos measuring 8 mm, 15 mm, 18.5 mm, and 22 mm were fixed in a 4% paraformaldehyde solution and sections obtained with magnetic resonance imaging (MRI) were compared to those prepared for light microscopy (LM), using the same embryos. The MRM and LM slices were of a similar quality. In the MRM sections, embryonic organs and systems were clearly visible, particularly the peripheral and central nervous systems, and the cardiovascular and digestive systems. The digitalization and clarity of the MRM images make them an ideal teaching aid that is suitable for students during the first years of a health-science degree, particularly medicine. As well as providing students with their first experience of MRM, these images allow students to access, at any time, all embryos used, to assess changes in the positions of different organs throughout their stages of development, and to acquire spatial vision, an absolute requirement in the study of human anatomy. We recommend that this technique be incorporated into the wealth of standard embryonic teaching methods already in use.     

UHPLC-MS/MS测定天仙藤中5种马兜铃酸类成分

目的 建立天仙藤中马兜铃酸类成分的液质联用检测分析方法。方法 采用Agilent SB-C₁₈(2.1 mm×50 mm,1.8 μm)色谱柱,以乙腈-体积分数0.1%-甲酸溶液为流动相梯度洗脱,流速0.3 mL·min^-1,以多反应监测模式,建立了同时测定天仙藤中马兜铃内酰胺AⅡ(ALAⅡ)、马兜铃酸Ⅳa(AAⅣa)、马兜铃内酰胺FⅠ(ALFⅠ)、马兜铃内酰胺Ⅰ(ALⅠ)和马兜铃酸Ⅰ(AAⅠ)共5种马兜铃酸类成分的液质联用检测方法。结果 ALAⅡ、AAⅣa、ALFⅠ、ALⅠ和AAⅠ分别在1.12~22.34、258.60~10 344.10、0.98~19.52、11.64~232.85、90.70~2 267.41 ng·mL^-1内线性关系良好;平均加样回收率分别为100.9%(相对标准偏差RSD 4.53%)、105.2%(RSD 4.83%)、102.6%(RSD 8.54%)、104.6%(RSD 3.64%)、114.6%(RSD 3.50%)。一共9批样品,其中有4批均检出上述5种马兜铃酸类成分;4批样品均检出除ALFⅠ外的其余4种马兜铃酸类成分;1批样品未检出AAI,检出其余4种马兜铃酸类成分。结论 上述建立的同时测定2种马兜铃酸和3种马兜铃内酰胺成分的液质联用方法经验证准确、可靠,能够用于马兜铃酸类成分的检测与分析。     

气相色谱串联质谱法测定二甲双胍格列本脲胶囊(Ⅱ)中N-亚硝基二甲胺的含量

目的:建立了二甲双胍格列本脲胶囊(Ⅱ)中基因毒性杂质N-亚硝基二甲胺(NDMA)的测定方法.方法:采用气相色谱-三重四级杆质谱仪,以多反应监测模式(MRM)进行测定,按外标法定量.仪器条件:EI源温度:230?℃;电子能量:70?eV;碰撞气:高纯氮气,碰撞气流速:1.5?mL/min.载气:高纯氦气,载气流速为1.0...     

磁共振脊髓水成像在脊柱病变中的应用

目的探讨磁共振脊柱水成像在脊柱病变诊断中的作用。方法使用日本东芝ExcelART1.5T超导磁共振机,对110例患者进行检查,分别做二维及三维成像,并配合脂肪抑制及预饱和技术,对三维图像做最大强度投影重建,将三维图像做多角度观察。结果MRM可显示椎管内“造影柱”的形态,椎管内外不同病变对造影柱造成的压迫各有特征,硬膜外病变导致患侧造影柱狭窄,硬膜下病变造成患侧造影柱扩大,脊髓向对侧移位,髓内病变造成造影柱均匀变窄。结论MRM对脊柱各种病变所导致的椎管改变可清晰显示,通过对造影柱形态的观察,可以对病变进行定位或定性的诊断,结合MR平扫诊断更为准确。     

液质联用法测定七宝美髯丸中5种成分的含量

目的：建立UPLC-PDA-MS/MS法同时测定七宝美髯丸中二苯乙烯苷、阿魏酸、金丝桃苷、补骨脂素、异补骨脂素的含量。方法：采用InertSustain^® C₁₈（3.0 mm×100 mm,3.0 μm）色谱柱,甲醇-0.05%甲酸水溶液,梯度洗脱,流速0.4 mL·min^-1,进样量10 μL;PDA扫描范围：200~400 nm;质谱采用电喷雾离子源（ESI源）,正负离子扫描切换,多重反应监测模式进行定量分析。结果：七宝美髯丸中5种成分在线性范围内峰面积与质量浓度均呈良好的线性关系,加样回收率为99.06%~102.24%,精密度RSD值小于2%。在所设定的色谱条件下,七宝美髯丸中5个成分（二苯乙烯苷、阿魏酸、金丝桃苷、补骨脂素和异补骨脂素）于10 min内完全分离。结论：建立的UPLC-PDA-MS/MS方法快速简便、精密度好、灵敏度高,可用于七宝美髯丸中多种成分的含量测定和质量控制。     

Simultaneous detection and quantitation of organic impurities in methamphetamine by ultra‐high‐performance liquid chromatography–tandem mass spectrometry,a complementary technique for methamphetamine profiling

The analysis of organic impurities plays an important role in the impurity profiling of methamphetamine, which in turn provides valuable information about methamphetamine manufacturing, in particular its synthetic route, chemicals, and precursors used. Ultra‐high‐performance liquid chromatography – tandem mass spectrometry (UHPLC – MS/MS) is ideally suited for this purpose due to its excellent sensitivity, selectivity, and wide linear range in multiple reaction monitoring (MRM) mode. In this study, a dilute‐and‐shoot UHPLC – MS/MS method was developed for the simultaneous identification and quantitation of 23 organic manufacturing impurities in illicit methamphetamine. The developed method was validated in terms of stability, limit of detection (LOD), lower limit of quantification (LLOQ), accuracy, and precision. More than 100 illicitly prepared methamphetamine samples were analyzed. Due to its ability to detect ephedrine/pseudoephedrine and its high sensitivity for critical target markers (eg, chloro‐pseudoephedrine, N‐cyclohexylamphetamine, and compounds B and P), more impurities and precursor/pre‐precursors were identified and quantified versus the current procedure by gas chromatography – mass spectrometry (GC – MS). Consequently, more samples could be classified by their synthetic routes. However, the UHPLC – MS/MS method has difficulty in detecting neutral and untargeted emerging manufacturing impurities and can therefore only serve as a complement to the current method. Despite this deficiency, the quantitative information acquired by the presented UHPLC – MS/MS methodology increased the sample discrimination power, thereby enhancing the capacity of methamphetamine profiling program (MPP) to conduct sample‐sample comparisons.     

Quantitative Prediction of Oral Bioavailability of a Lipophilic Antineoplastic Drug Bexarotene Administered in Lipidic Formulation Using a Combined In Vitro Lipolysis/Microsomal Metabolism Approach

For performance assessment of the lipid-based drug delivery systems (LBDDSs), in vitro lipolysis is commonly applied because traditional dissolution tests do not reflect the complicated in vivo micellar formation and solubilization processes. Much of previous research on in vitro lipolysis has mostly focused on rank-ordering formulations for their predicted performances. In this study, we have incorporated in vitro lipolysis with microsomal stability to quantitatively predict the oral bioavailability of a lipophilic antineoplastic drug bexarotene (BEX) administered in LBDDS. Two types of LBDDS were applied: lipid solution and lipid suspension. The predicted oral bioavailability values of BEX from linking in vitro lipolysis with microsomal stability for lipid solution and lipid suspension were 34.2 ± 1.6% and 36.2 ± 2.6%, respectively, whereas the in vivo oral bioavailability of BEX was tested as 31.5 ± 13.4% and 31.4 ± 5.2%, respectively. The predicted oral bioavailability corresponded well with the oral bioavailability for both formulations, demonstrating that the combination of in vitro lipolysis and microsomal stability can quantitatively predict oral bioavailability of BEX. In vivo intestinal lymphatic uptake was also assessed for the formulations and resulted in <1% of the dose, which confirmed that liver microsomal stability was necessary for correct prediction of the bioavailability.     

Bariatric surgery in severely obese adolescents improves major comorbidities including hyperuricemia

Objective

Serum uric acid (sUA) is believed to contribute to the pathogenesis of metabolic comorbidities like hypertension, insulin-resistance (IR) and endothelial dysfunction (EDF) in obese children. The present pilot study investigated the association between sUA concentrations and loss of body weight following laparoscopic sleeve gastrectomy (LSG) or laparoscopic Roux-en-Y-gastric bypass (RYGB) in severely obese adolescents.

Materials/Methods

10 severely obese adolescents underwent either LSG (n = 5) or RYGB (n = 5). 17 normal weight, healthy, age- and gender-matched adolescents served as a normal weight peer group (NWPG). Pre- and 12 months postoperatively, sUA and relevant metabolic parameters (glucose homeostasis, transaminases, lipids) were compared.

Results

Preoperatively, sUA was significantly elevated in patients with severe obesity compared to NWPG. Twelve months after LSG and RYGB, a significant decrease in sUA, BMI, CVD risk factors, hepatic transaminases, and HOMA-IR was observed. Reduction in SDS-BMI significantly correlated with changes in sUA.

Conclusions

sUA levels and metabolic comorbidities improved following bariatric surgery in severely obese adolescents. The impact of changes in sUA on long-term clinical complications of childhood obesity deserves further study.     

Magnetic Recording Method (MRM) for Nondestructive Evaluation of Ferromagnetic Materials

This paper proposes and experimentally investigates a novel nondestructive testing method for ferromagnetic elements monitoring, the Magnetic Recording Method (MRM). In this method, the inspected element must be magnetized in a strictly defined manner before operation. This can be achieved using an array of permanent magnets arranged to produce a quasi-sinusoidal magnetization path. The magnetic field caused by the original residual magnetization of the element is measured and stored for future reference. After the operation or loading, the magnetic field measurement is repeated. Analysis of relative changes in the magnetic field (for selected components) allows identifying applied stress. The proposed research methodology aims to provide information on the steel structure condition unambiguously and accurately. An interpretation of the results without referring to the original magnetization is also possible but could be less accurate. The method can be used as a standard technique for NDT (Non-Destructive Testing) or in structural health monitoring (SHM) systems.     

Magnetic resonance microscopy of mammalian neurons

Magnetic resonance imaging (MRI) is now a leading diagnostic technique. As technology has improved, so has the spatial resolution achievable. In 1986 MR microscopy (MRM) was demonstrated with resolutions in the tens of micrometers, and is now an established subset of MRI with broad utility in biological and non-biological applications. To date, only large cells from plants or aquatic animals have been imaged with MRM limiting its applicability. Using newly developed microsurface coils and an improved slice preparation technique for correlative histology, we report here for the first time direct visualization of single neurons in the mammalian central nervous system (CNS) using native MR signal at a resolution of 4–8 μm. Thus MRM has matured into a viable complementary cellular imaging technique in mammalian tissues.