中小学生眼屈光度动态变化与近视眼的追踪调查研究

目的　探索学生半年眼屈光度变化与近视眼发病规律。方法　对７０８ 名学生眼屈光度与近视眼发病情况进行了追踪调查。结果　６ ～１４ 岁学生各年龄组段眼屈光度半年下降均值为０－２８２Ｄ～０－４６５Ｄ,其中远视屈光度下降均值为＋ ０－１２２Ｄ～＋ ０－３９７Ｄ。学生在６ 岁时已有近视眼发生,６ ～１４ 岁学生近视眼新发病率为４－４４ ％ ～２３－９６ ％ （ Ｐ＜ ０－０１） 。有近视眼家族史的学生近视眼新发病率出现高峰年龄为８ 岁,无家族史者为１０ 岁。学生远视屈光度逐渐下降,下降幅度随年龄组段的递增而减少。学生近视眼新发病率随年龄组段递增而上升,有近视眼家族史的学生发病高峰年龄比无近视眼家族史者提前２ 岁。结论　远视屈光度下降幅度大小可作为预测学生近视眼发生与否的重要参数。     

渗透树脂对树脂充填体釉质边缘漂白后微渗漏的影响研究#br#

目的    研究渗透树脂对树脂充填体釉质边缘漂白后微渗漏的影响。方法    选择由郑州大学第一附属医院口腔颌面外科门诊提供的因阻生而拔除的第三磨牙45颗,并在其颊面颈部制备V类洞。将所有离体牙随机分为3组,每组15颗,根据操作方法分别记为树脂充填组、树脂充填+冷光美白组和树脂充填+冷光美白+渗透树脂组。3组离体牙充填后进行500次冷热温度循环,然后在2%的碱性品红溶液中浸泡24 h,把离体牙沿颊舌向纵向剖开,用体式显微镜观察,并用S-EYE软件测量染料渗透深度。结果    3组染料渗透深度总的比较,差异有统计学意义（H = 10.182,P < 0.05）。其中,树脂充填+冷光美白组染料渗透深度大于树脂充填组和树脂充填+冷光美白+渗透树脂组,差异均有统计学意义（P < 0.05）;树脂充填+冷光美白+渗透树脂组染料渗透深度与树脂充填组相比,差异无统计学意义（P > 0.05）。结论    漂白剂加重了树脂充填体边缘的微渗漏,同时渗透树脂的应用能有效减少漂白剂对树脂充填体边缘微渗漏的影响。     

招收飞行学员远视力标准降至0.8后屈光状态分析

目的探讨招收飞行学员远视力标准降至08后,视力合格学生的屈光状态。方法2012年3月—2013年3月参检学生290名,按照每只眼的远视力分组,视力0.8~0.9分为A组、1.0~2.0分为B组,2组学生散瞳后接受检影验光,观察其屈光状态。结果A组90.47%的参检学生眼屈光度在体检标准合格范围内,B组90.77%的参检学生眼屈光度在体检标准合格范围内,2组比较差异无统计学意义（P>0.05)。结论招收飞行学员远视力标准降至0.8后,眼屈光度在体检标准合格范围内,合格人数大幅增加,满足了招飞需求。     

成人睫状肌麻痹前后屈光度变化及其影响因素的流行病学研究

目的探讨成人睫状肌麻痹前后屈光度变化及其影响因素的流行病学特点。 方法收集2012年5月至2013年6月在中国河北省邯郸永年县进行眼科屈光检查710例(1410只眼)的资料。其中,男性364例(721只眼),女性346例(689只眼);年龄30~83岁,平均年龄(50.9±10.3)岁。采用自动电脑验光仪检测所有受检者睫状肌麻痹前后的屈光度。采用眼科A型超声检查所有受检者睫状肌麻痹前的眼部生物学参数。所有受检者睫状肌麻痹前后等效球镜(SE)的描述采用均数±标准差表示,两者的比较采用配对t检验。不同年龄受检者睫状肌麻痹前后SE的一致性,采用Bland-Altman plots进行评估。不同性别间睫状肌麻痹后SE与睫状肌麻痹前角膜曲率K值(K)、前房深度(ACD)、眼轴长度(AL)、睫状肌麻痹后中央角膜厚度(LT)、晶状体混浊程度(NO)、晶状体核的颜色(NC)、晶状体皮质(C)及晶状体后囊下混浊的程度(PSC)的比较,采用线性混合模型分析。采用Pearson相关分析检验各屈光指标间的相关性。 结果710例(1410只眼)受检者睫状肌麻痹前的平均SE为(-0.37±1.22)D,睫状肌麻痹后的平均SE为(0.13±1.11)D。经t检验,两者的差异有统计学意义(t＝-25.75,P<0.05)。Bland-Altman plots分析显示睫状肌麻痹后的SE发生远视漂移,且随年龄的增加该漂移逐渐减小。所有受检者睫状肌麻痹前的K值、CCT、ACD及AL,以及睫状肌麻痹后的LT、NO、NC、C及PSC分别为(44.02±1.51)D、(2.88±0.36)mm、(23.07±0.95)mm、(4.52±0.41)mm、(2.72±0.43)、(2.72±0.43)、(0.26±0.63)及(0.13±0.26)。睫状肌麻痹后的LT、NO、NC、C与SE呈正相关。经Pearson相关分析,其相关性具有统计学意义(r＝0.13,0.11,0.11,0.07;P<0.05)。受检者睫状肌麻痹前的K值、ACD、AL及睫状肌麻痹后的PSC与SE呈负相关(r＝-0.12,-0.17,-0.20,-0.13;P<0.05)。近视眼与睫状肌麻痹前的AL、睫状肌麻痹后的NO、NC、C及PSC呈负相关。经Pearson相关分析,其相关性具有统计学意义(r＝-0.22,-0.15,-0.15,-0.14,-0.42;P<0.05)。 结论受检者睫状肌麻痹后SE发生明显的远视漂移,且随年龄增加此现象逐渐减小。睫状肌麻痹前的K、ACD、AL,以及睫状肌麻痹后的LT、NO、NC、C和PSC均与SE相关,其中影响近视眼的因素有AL、NO、NC、C及PSC。     

Trans-PRK、FS-LASIK和SMILE矫正近视散光的对比观察

目的 探讨Trans-PRK、FS-LASIK和SMILE矫正近视散光的临床效果。方法 选择Trans-PRK组54眼、FS-LASIK组55眼和SMILE组56眼进行回顾性病例研究,随访6个月,比较三组的术前术后各个时间点的视力、屈光度、高阶像差,评估三种不同术式的安全性、有效性。结果 (1)三组术前基线数据差异无统计学意义(P=0.148, 0.148, 0.31, 0.285, 0.283, 0.901);(2)术后1、3、6个月三组之间的UCVA差异无统计学意义(P=0.902),组内比较时Trans-PRK组术后6个月视力高于术后1个月差异具有统计学意义(χ²=0.571,P=0.014);(3)三组间只有在术后1个月柱镜度数差异具有统计学意义(χ²=9.411,P=0.009),两两比较时FS-LASIK组柱镜度数小于SMILE组差异具有统计学意义(χ²=24.400,P=0.004),在术后3、6个月三组之间的柱镜度数差异无统计学意义(P=0.159, 0.106);(4)术后1、3、6个月三组之间的SE差...     

人工晶体屈光度回归公式的探讨

针对目前临床上常用的ＳＲＫⅡ公式在计算人工晶体屈光度时的局限性，对４１５只后房型人工晶体眼的角膜屈光力、眼轴长度和正视化人工晶体屈光度进行回归分析后，设计出一种不同于传统的线性回归公式的曲线回归公式——二元三次计算公式。结果：二元三次回归公式为一单调递增曲线，呈连续分布，不分区间。利用二元三次回归公式计算的总体标准差小于ＳＲＫⅡ公式的总体标准差。结论：二元三次曲线回归公式计算法有助于临床更准确地进行人工晶体屈光度的计算     

CB2 cannabinoid receptor agonist enantiomers HU-433 and HU-308: An inverse relationship between binding affinity and biological potency

Activation of the CB2 receptor is apparently an endogenous protective mechanism. Thus, it restrains inflammation and protects the skeleton against age-related bone loss. However, the endogenous cannabinoids, as well as Δ⁹-tetrahydrocannabinol, the main plant psychoactive constituent, activate both cannabinoid receptors, CB1 and CB2. HU-308 was among the first synthetic, selective CB2 agonists. HU-308 is antiosteoporotic and antiinflammatory. Here we show that the HU-308 enantiomer, designated HU-433, is 3–4 orders of magnitude more potent in osteoblast proliferation and osteoclast differentiation culture systems, as well as in mouse models, for the rescue of ovariectomy-induced bone loss and ear inflammation. HU-433 retains the HU-308 specificity for CB2, as shown by its failure to bind to the CB1 cannabinoid receptor, and has no activity in CB2-deficient cells and animals. Surprisingly, the CB2 binding affinity of HU-433 in terms of [³H]CP55,940 displacement and its effect on [³⁵S]GTPγS accumulation is substantially lower compared with HU-308. A molecular-modeling analysis suggests that HU-433 and -308 have two different binding conformations within CB2, with one of them possibly responsible for the affinity difference, involving [³⁵S]GTPγS and cAMP synthesis. Hence, different ligands may have different orientations relative to the same binding site. This situation questions the usefulness of universal radioligands for comparative binding studies. Moreover, orientation-targeted ligands have promising potential for the pharmacological activation of distinct processes.The CB2 cannabinoid receptor functions as an endogenous protective entity (1). Thus, it is an important regulator of bone mass and inflammation. It represents a therapeutic target that avoids the undesired psychotropic effects caused by CB1 receptor activation. CB2 is expressed in osteoblasts, the bone-forming cells, and in osteoclasts, the bone-resorbing cells (2). Monocytes/macrophages, B cells, certain T-cell subtypes, and mast cells also express CB2 (3–7). In the skeleton, activation of CB2 favors bone formation over resorption, thus protecting the skeleton against age-related bone loss. Inflammatory responses are restrained by CB2 agonists in several instances such as hepatic ischemia-reperfusion injury (8), uveitis (9), and contact dermatitis (10). With their terpene and resorcinol-derived moieties, some synthetic CB2 agonists, such as HU-308 (10), JWH-133 (11), and HU-910 (12), structurally resemble the phytocannabinoids Δ⁹-tetrahydrocannabinol and cannabidiol. Other, non-phytocannabinoid-type agonists have been also reported (13). HU-308 was one of the first fully characterized, highly selective, and highly efficacious cannabinoid type-2 agonist (10). It has three chiral centers, namely, at carbon atoms in positions 3, 4, and 6 (Scheme 1). HU-308 has a 3R, 4S, 6S configuration; that of its enantiomer (HU-433) is 3S, 4R, 6R.Open in a separate windowScheme 1.Structures of HU-433 and -308.In most experiments, the optimal HU-308 mitogenic activity in osteoblasts, as well as its antiosteoclastogenic effect, was obtained by using concentrations in the nanomolar range (2, 14). Surprisingly, testing a new HU-308 batch, we noticed a 3- to 4-magnitude decrease in the dose that triggers optimal proliferative response in osteoblasts, reasoning that this preparation contained a significant amount of the HU-308 enantiomer, presumably responsible for the enhanced activity. We report here that this enantiomer, designated HU-433, was synthesized and compared with HU-308, and indeed showed markedly enhanced bone-anabolic and antiinflammatory activities, but inferior CB2 receptor binding affinity. Although both enantiomers seem to target the same binding pocket, two different orientations relative to the binding site are possible, leading to different behavior of the two enantiomers due to their different occupancy of these orientations. This observation appears to reflect a situation in which relatively small differences in possible binding conformations of the ligands within the receptor—referred to as poses—lead to significant diminution of receptor-binding properties and a marked increase in biological activity.     

Acute disseminated encephalomyelitis in children as the result of aseptic meningitis - a report of two cases

Acute disseminated encephalomyelitis (ADEM) is an inflammation of the spinal cord and brain. Diagnosis of ADEM, due to its rare occurrence and lack of definite laboratory indices, is difficult and is never totally certain. The clinical criterion required for the diagnosis is presence of acute symptoms from the brain and/or spine with fever, occurring after viral or bacterial infection, vaccination or serum administration. Differentiation between ADEM and acute multiple sclerosis in children is difficult, and diagnosis of ADEM may only be confirmed after years of observation, especially as multiple sclerosis is more common than ADEM. The most useful tool in differentiation between the two diseases is MRI. The aim of the study was to present two cases of ADEM with unknown aetiology after aseptic meningitis in children.     

Assessment of a novel deep learning-based marker-less motion capture system for gait study

BackgroundMarker-less systems based on digital video cameras and deep learning for gait analysis could have a deep impact in clinical routine. A recently developed system has shown promising results in terms of joint center position but has not been yet evaluated in terms of gait outcomes.Research questionHow does this novel marker-less system compare to a marker-based reference system in terms of clinically relevant gait parameters?MethodsThe deep learning method behind the developed marker-less system was trained on a dedicated dataset consisting of forty-one asymptomatic and pathological subjects each performing ten walking trials. The system could estimate the three-dimensional position of seventeen joint centers or keypoints (e.g., neck, shoulders, hip, knee, and ankles). We evaluated the marker-less system against a marker-based system in terms of differences in joint position (Euclidean distance), detection of gait events (e.g., heel strike and toe-off), spatiotemporal parameters (e.g., step length, time), kinematic parameters (e.g., hip and knee extension-flexion), and inter-trial reliability for kinematic parameters.ResultsThe marker-less system was able to estimate the three-dimensional position of joint centers with a mean difference of 13.1 mm (SD = 10.2 mm). 99% of the estimated gait events were estimated within 10 ms of the corresponding reference values. Estimated spatiotemporal parameters showed zero bias. The mean and standard deviation of the differences of the estimated kinematic parameters varied by parameter (for example, the mean and standard deviation for knee extension flexion angle were −3.0° and 2.7°). Inter-trial reliability of the measured parameters was similar to that of the marker-based references.SignificanceThe developed marker-less system can measure the spatiotemporal parameters within the range of the minimum detectable changes obtained using the marker-based reference system. Moreover, except for hip extension flexion, the system showed promising results in terms of several kinematic parameters.