Hemochromatosis: pathophysiology,evaluation, and management of hepatic iron overload with a focus on MRI

Introduction: Hereditary hemochromatosis (HH) is an autosomal recessive disorder that occurs in approximately 1 in 200–250 individuals. Mutations in the HFE gene lead to excess iron absorption. Excess iron in the form of non-transferrin-bound iron (NTBI) causes injury and is readily uptaken by cardiomyocytes, pancreatic islet cells, and hepatocytes. Symptoms greatly vary among patients and include fatigue, abdominal pain, arthralgias, impotence, decreased libido, diabetes, and heart failure. Untreated hemochromatosis can lead to chronic liver disease, fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Many invasive and noninvasive diagnostic tests are available to aid in diagnosis and treatment. MRI has emerged as the reference standard imaging modality for the detection and quantification of hepatic iron deposition, as ultrasound (US) is unable to detect iron overload and computed tomography (CT) findings are nonspecific and influenced by multiple confounding variables. If caught and treated early, HH disease progression can significantly be altered.

Area covered: The data on Hemochromatosis, iron overload, and MRI were gathered by searching PubMed.

Expert commentary: MRI is a great tool for diagnosis and management of iron overload. It is safe, effective, and a standard protocol should be included in diagnostic algorithms of future treatment guidelines.     

SWE联合灰阶超声评估不同分度子宫脱垂初产妇会阴体变化

目的利用实时剪切波弹性成像技术(SWE)联合灰阶超声探讨产后不同分度子宫脱垂初产妇会阴体弹性和形态的变化。方法选取2019年1月~2019年12月200例产后6~8周,患有子宫脱垂且经阴道单胎足月顺产的初产妇为观察对象。通过经阴道超声检查,结合POP分度标准,将患有Ⅰ度子宫脱垂的65例初产妇纳入B组,Ⅳ度子宫脱垂的46例初产妇纳入C组。收集同期健康已婚未育女性50例作为对照,纳入A组。分别在静息及缩肛状态下,测量三组观察对象会阴体的高度及深度,采集各组会阴体的杨氏模量值。结果三组观察对象的会阴体收缩幅度差值(高度、深度)在缩肛、静息两种状态下,差异有统计学意义(P均<0.05);静息及缩肛两种状态下健康对照组会阴体的平均杨氏模量值较Ⅰ度子宫脱垂组、Ⅳ度子宫脱垂组高,且Ⅰ度子宫脱垂组高于Ⅳ度子宫脱垂组,各组间差异均有统计学意义(P<0.05)。结论产后子宫脱垂初产妇会阴体弹性明显降低,收缩功能减弱,且会阴体收缩功能减低程度与子宫脱垂程度有关。     

Effect of oscillation on elevating shear stresses

The effect of oscillation on elevating turbulent shear stresses through the Jellyfish and St. Vincent valves has been investigated. Laser Doppler anemometry was employed to determine the velocity and shear stress distributions at various locations downstream of the valves. Comparison between two valves revealed that at 0.5D downstream of the valves the magnitude of shear stresses in the Jellyfish valve were much higher than those of the St. Vincent valve at cardiac outputs of 4, 5.5 and 7 l min^?1. The cause of high shear stresses in close proximity to the Jellyfish valve could be attributed to the oscillation of the membrane which in turn generated a wake downstream of the valve (in the core of valve chamber) and produced a wide region of disturbance further downstream. This resulted in further pressure drag, and consequently higher pressure drops across the valve and higher shear stresses downstream of the valve.     

螺旋弯曲管中血液两相流动分析

目的 经典的单相牛顿血液流动模型忽略了红细胞与血浆之间的相互作用以及血液剪切变稀性质。为了解决这些问题,采用多相的非牛顿模型研究冠状动脉模型的血流动力学参数。方法 把血液考虑为血浆和红细胞的混合体,并用螺旋弯曲血管模型模拟冠状动脉,分析冠状动脉内红细胞的运动以及红细胞体积分数的分布情况,并与单相非牛顿血液模型的模拟结果进行对比。结果 单相和多相血液模型模拟下的截面壁面剪切力平均值差别不明显,但是在两相流模拟中,螺旋弯曲管下底壁面处存在明显的红细胞聚集现象,同时还分布着较低的壁面剪切力。结论 引用多相流数值模拟得到了螺旋弯曲管中的血流动力学参数,同时发现红细胞在螺旋弯曲管下底面处聚集的现象,这很容易诱发血栓形成,与临床上所观察到的粥样硬化斑块经常出现在冠状动脉弯曲内侧是相符合的,可进一步说明动脉粥样硬化病变的发生机制。     

流动剪应力对丹酚酸B抑制血小板聚集的影响

目的研究流动剪应力对丹酚酸B抑制血小板聚集的影响及其可能的机制。方法采用生物力药理学的研究方法,2×4析因设计分组,利用BioFlux 1000控剪应力微流培养系统,分别施以0.02、1.5 Pa剪应力并联合4个剂量的丹酚酸B对血管内皮细胞(HUVECs)进行预处理20 h,收集上清液,采用联酶免疫吸附法(ELISA)检测细胞上清液中6-keto-PGF1α和vWF含量;检测上清液对ADP诱导的血小板聚集的影响;免疫荧光法分析流动内皮细胞胞浆vWF含量。结果与低剪应力流动条件相比,1.5 Pa剪应力联合100μg/mL丹酚酸B能显著提高内皮细胞分泌6-keto-PGF1α的量(P<0.05);细胞上清液明显抑制了血小板聚集(P<0.05)。剪应力的变化显著影响血管内皮细胞释放vWF(P<0.01),而丹酚酸B对血管内皮细胞释放vWF无明显影响。结论丹酚酸B可能通过促进血管内皮细胞分泌PGI2发挥抗血小板聚集的效应。从血流/血管/血液相互作用的角度看,正常的流动剪应力是丹酚酸B发挥抗血小板聚集效应的有利条件之一。     

Lithium di silicate ceramic surface treated with Er,Cr:YSGG and other conditioning regimes bonded to orthodontic bracket

AimTo assess bond integrity and modes of failure of metallic brackets to lithium disilicate ceramics (LDC) conditioned with Er,Cr:YSGG laser (ECL).Material and methodsSixty LDC were arbitrarily allocated into six groups (n = 15) according to the type of ceramic surface conditioning treatment. Group 1 surface treated with silane (S) only, group 2 surface etched with hydrofluoric acid (HF)+ S, group 3 surface conditioned with HF+ ultrasonic bath (UB)+ S, group 4 sand blasting (SB) of glass ceramic surface with 50 µm Al₂O₃, group 5 surface conditioned with self-etch ceramic primer (SECP) and in group 6 surface treated with ECL + S. After conditioning, the specimens were positioned in a universal testing device for shear bond strength (SBS) testing. Adhesive Remnant Index (ARI) was used to determine sites of bond failure. Among experimental groups analysis of variance (ANOVA) and Tukey multiple comparison test was used at a significance level of (p < 0.05).ResultsThe highest SBS values were observed in group 3 HF+ UB + S (18.21 ± 1.241) and the lowest SBS values were displayed group 1 surface treated with S only (5.21 ± 0.23). Specimens surface conditioned in group 2 with HF+ S (17.85 ± 1.25), group 3 HF+ UB + S (18.21 ± 1.241) and group 6 ECL + S (17.09 ± 1.114) unveiled comparable SBS values (p > 0.05).ConclusionLDC conditioned with ECL at (4.5 W and 30 Hz) has a potential to be used in clinical settings alternate to HF acid.     

急性肌肉拉伤的MRI应用进展

急性肌肉拉伤是一种急性间接肌肉损伤,常见于日常生活和运动中。仅根据临床症状和体格检查难以准确诊断。常规MRI软组织分辨率高,是急性肌肉拉伤诊断和预后评估的重要手段。近年发展的肌肉MR弹性成像、T2弛豫时间图、磁共振扩散加权成像、扩散张量成像和磁共振波谱具有从微观结构、病理和生理层面为急性肌肉拉伤的诊断提供定量、客观依据的潜力。作者对应用于急性肌肉拉伤的各项MRI技术进行综述。     

剪切波弹性成像诊断腮腺占位性病变的应用价值

目的:通过剪切波弹性成像(shear wave elastrography,SWE)获得鉴别腮腺良恶性病变及良性亚组分型的杨氏模量值,并分析其诊断价值。方法:选取2019年6月至2020年1月以腮腺占位性病变住院的74例患者(76个结节),对所有患者的腮腺病变在术前或穿刺活检之前进行SWE技术检查,获得相应的杨氏模量值,并与组织学检查结果进行比较和分析。结果:在76个结节中,良性病变69例,恶性病变7例。良性病变中多形性腺瘤(pleomorphic adenoma,PA)占37.6%(26例),单形性腺瘤(monomorphic adenoma,MA)占30.0%(23例),淋巴结占21.7%(15例)。所有腮腺肿瘤杨氏模量最大值及平均值均高于腮腺内淋巴结,差异均有统计学意义(P<0.05)。PA与MA比较杨氏模量最大值及平均值差异有统计学意义(P<0.05)。腮腺恶性病变与良性病变比较,杨氏模量最大值及平均值差异有统计学意义(P<0.05),但是恶性病变与良性病变各亚组之间比较,除淋巴结组之外,杨氏模量最大值及平均值差异均无统计学意义(P>0.05)。结论:SWE技术虽然在鉴别腮腺良恶性肿瘤之间没有达到预期效果,但在良性亚组(PA与MA、淋巴结与其他腮腺肿瘤)之间有重要的诊断意义。     

The Immediate Effects of Foam Rolling and Stretching on Iliotibial Band Stiffness: A Randomized Controlled Trial

BackgroundIliotibial Band Syndrome (ITBS) is a common clinical condition likely caused by abnormal compressive forces to the iliotibial band (ITB). Stretching interventions are common in ITBS treatment and may predominantly affect tensor fascia latae (TFL). Another ITBS treatment is foam rolling, which may more directly affect the ITB. Shear wave ultrasound elastography (SWUE) measures real-time soft tissue stiffness, allowing tissue changes to be measured and compared.PurposeTo examine effects of foam rolling and iliotibial complex stretching on ITB stiffness at 0˚ and 10˚ of hip adduction and hip adduction passive range of motion (PROM).Study DesignRandomized controlled trial.MethodsData from 11 males (age = 30.5 ± 9.0 years, Body Mass Index (BMI) = 27.8 ± 4.0) and 19 females (age = 23.5 ± 4.9, BMI = 23.2 ± 2.1) were analyzed for this study. Subjects were randomly assigned to one of three groups: control, stretching, and foam rolling. Shear wave ultrasound elastography measurements included ITB Young’s modulus at the mid-thigh, the distal femur and the TFL muscle belly. ITB-to-femur depth was measured at mid-thigh level. Hip adduction PROM was measured from digital images taken during the movement.ResultsNo significant interactions or main effects were found for group or time differences in ITB Young’s modulus at the three measured locations. The ITB stiffness at the mid-thigh and distal femur increased with 10° adduction, but TFL stiffness did not increase. A main effect for adduction PROM was observed, where PROM increased 0.8˚ post-treatment (p = 0.02).ConclusionA single episode of stretching and foam rolling does not affect short-term ITB stiffness. The lack of ITB stiffness changes may be from an inadequate intervention stimulus or indicate that the interventions have no impact on ITB stiffness.Levels of Evidence1b