Optokinetic nystagmus and after-nystagmus during a 6 hour bedrest study

Conclusions. A lengthy alteration of gravity direction produced different effects on the intrinsic horizontal and vertical optokinetic oculomotor systems. Objective. To examine both optokinetic nystagmus (OKN) and optokinetic after-nystagmus (OKAN) in a 6 h 6° head-down bedrest study, in which the subjects were kept lying under simulated micro-gravity conditions. Subjects and methods. In six normal healthy adults, we repeatedly (five times) and comparatively studied OKN and OKAN evoked by horizontal and vertical stimuli. Stage 1 was an upright sitting position. During the 6 h bedrest condition, we studied OKN and OKAN in 90° recumbent lateral positions (stages 2, 3, and 4). In stage 5 the subject returned to an upright position. Results. We confirmed that the change in gravity direction had various effects on the condition of OKN and OKAN. Also, we found that it took more than 3 h to reach a desirable level of systemic adaptive modification to the unique environmental condition. We considered that the early change was basically due to the changes in sensory inputs through the otolith organs, and the latter changes represented the adaptive process of the spatial orientation system. During the tilt, the occurrence rates of both horizontal and vertical OKANs were decreased; however, the conditions of these changes were different.     

Two cases of recovery of occlusion by a combination of surgery and orthodontic therapy for adult mandibular impacted teeth

We experienced 2 patients in which occlusion was successfully recovered by a combination of surgical subluxation and orthodontic therapy for adult mandibular impacted teeth. Of these cases, the tooth in one case was still vital after completion of the treatment. Herein, we report these 2 cases with a review of the literature.     

近视性黄斑区视网膜劈裂的临床特征及危险因素分析

目的 分析老年高度近视人群黄斑区视网膜劈裂（myopic macular retinoschisis，MRS）的临床特征，探讨不同程度MRS发生的危险因素。 方法 横断面研究。2016年上海市成年人高度近视流行病学调查项目中的老年高度近视238例238眼纳入研究，按照MRS的程度分为5组：无劈裂(S0)、中心凹外劈裂(S1)、中心凹劈裂(S2)、中心凹+中心凹外劈裂(S3)、全黄斑区劈裂（S4）。无黄斑劈裂（S0）组设为对照组。研究对象均实施全面的眼科检查。观察近视萎缩性黄斑病变(atrophic myopic maculopathy，AMM)的分级、黄斑前膜（epiretinal membrane，ERM）和玻璃体黄斑牵拉(vitreomacular traction，VMT)的状态，基于SS-OCT测量黄斑区不同方位黄斑巩膜高度（macular scleral height, MSH）。 结果 238眼中存在MRS的89眼（37.4%），与对照组间年龄、性别均无显著差异（P>0.05）。MRS组鼻侧、颞侧及下方MSH显著高于对照组(P＜0.05)，ERM、VMT和A2以上AMM发生率在MRS组中更高(P＜0.05)。眼轴、黄斑巩膜高度、VMT、严重AMM是MRS发生的危险因素。在MRS各组间，S2组眼轴最短 (P＜0.001)，A1以下轻症AMM比例最大（36.4%）（P=0.046），与S0组更为接近。 结论 长眼轴、黄斑区后巩膜膨出、玻璃体黄斑界面牵拉和严重的萎缩性病变是MRS形成的危险因素。中心凹劈裂与中心凹外劈裂形成机制可能存在差异，需要长期队列研究进一步证实。     

The practical radius of a pencil beam in proton therapy

The central Gaussian shaped high dose region of a pencil beam (PB) in light ion beam therapy (LIBT) is enveloped by a low dose region causing non-negligible field size effects and impairs the dose calculation accuracy considerably if the low dose envelope is not well modeled. The purpose of this study was to calculate the practical radius, R_c, at which a PB does not influence a field more than a certain accuracy level.Lateral dose profiles of proton beams in water were simulated using GATE/Geant4. Those lateral dose profiles were integrated numerically and used to calculate field size factors (FSFs). The R_c was then determined such, that the lateral dose at radii exceeding R_c can be neglected without compromising the FSF of a 20 cm × 20 cm field more than a desired accuracy level c. The practical radius R_c yielding c = 0.5% was compared to the frequently applied concept of full width at a ratio x of the maximum (FWxM). The sensitivity to variations of the beam width was tested by increasing the initial beam width σ_C of the clinical beam model by 0.5 and 1 mm, respectively.Neglecting the dose at radii exceeding R_c resulted in the desired FSF accuracy, whereas using the FW0.01%M cut resulted in varying accuracy. In order to yield a constant FSF accuracy, the ratio x in FWxM ranged from 0.003% to 0.065% of the maximum. In contrast to R_c, FWxM was sensitive to variations of the initial beam width. The maximum R_c over all depths was less than 7 cm for the low(62.4 MeV) and medium(148.2 MeV) proton energy beam, which suggests that a plane parallel ionization chamber exceeding that radius is sufficient to acquire laterally integrated depth dose distributions for those energies. However, this holds not true for the highest energy (252.7 MeV) or when including a range shifter (RaShi). The values of R_c are specific to our beam line configuration as the maximum R_c was depending on both, the scattering material in the Nozzle as well as the distance of the air-gap between Nozzle and phantom.     

三维曲度牵引联合电针治疗神经根型颈椎病临床疗效观察

目的:观察三维曲度牵引联合电针治疗神经根型颈椎病的临床疗效。方法:将62例伴有颈椎曲度异常的神经根型颈椎病患者随机分为治疗组和对照组,每组31例。治疗组采用三维曲度牵引联合电针治疗,对照组采用普通坐位枕颌套牵引联合电针治疗。分别在治疗前、治疗后、疗程结束后3个月随访时对2组患者颈椎视觉模拟评分法(VAS)评分、颈椎曲度指数等指标进行观察;治疗后进行临床疗效评定。结果:治疗组痊愈17例,显效8例,有效4例,无效2例,总有效率为93.55%;对照组痊愈9例,显效7例,有效6例,无效9例,总有效率为70.97%。2组比较,差异有统计学意义(P<0.05)。治疗后及随访时,2组VAS评分、颈椎曲度指数较治疗前均有改善(P<0.05),且治疗组优于对照组(P<0.05)。随访时,2组VAS评分、颈椎曲度指数与治疗后比较,差异均有统计学意义(P<0.05)。结论:三维曲度牵引联合电针治疗神经根型颈椎病能明显改善患者的临床症状,纠正或改善患者的异常颈椎曲度,疗效持久确切,值得临床推广使用。     

Characterization of phthalate exposure among pregnant women assessed by repeat air and urine samples

BACKGROUND: Although urinary concentrations of phthalate metabolites are frequently used as biomarkers in epidemiologic studies, variability during pregnancy has not been characterized. METHODS: We measured phthalate metabolite concentrations in spot urine samples collected from 246 pregnant Dominican and African-American women. Twenty-eight women had repeat urine samples collected over a 6-week period. We also analyzed 48-hr personal air samples (n = 96 women) and repeated indoor air samples (n = 32 homes) for five phthalate diesters. Mixed-effects models were fit to evaluate reproducibility via intraclass correlation coefficients (ICC). We evaluated the sensitivity and specificity of using a single specimen versus repeat samples to classify a woman's exposure in the low or high category. RESULTS: Phthalates were detected in 85-100% of air and urine samples. ICCs for the unadjusted urinary metabolite concentrations ranged from 0.30 for mono-ethyl phthalate to 0.66 for monobenzyl phthalate. For indoor air, ICCs ranged from 0.48 [di-2-ethylhexyl phthalate (DEHP)] to 0.83 [butylbenzyl phthalate (BBzP)]. Air levels of phthalate diesters correlated with their respective urinary metabolite concentrations for BBzP (r = 0.71), di-isobutyl phthalate (r = 0.44), and diethyl phthalate (DEP; r = 0.39). In women sampled late in pregnancy, specific gravity appeared to be more effective than creatinine in adjusting for urine dilution. CONCLUSIONS: Urinary concentrations of DEP and DEHP metabolites in pregnant women showed lower reproducibility than metabolites for di-n-butyl phthalate and BBzP. A single indoor air sample may be sufficient to characterize phthalate exposure in the home, whereas urinary phthalate biomarkers should be sampled longitudinally during pregnancy to minimize exposure misclassification.     

自制面模具在颧弓骨折外牵引辅助治疗中的应用

目的 探讨自制面模具在颧弓骨折复位术后的临床疗效,研究其在预防并发症方面所起的作用。 方法 对自愿接受自制面模具作为外牵引固定的颧弓骨折患者26例,以自制面膜具施行外牵引固定,术后对骨折愈合和并发症（如骨折错位、局部感染等情况）进行临床观察。结果 26例均于4周后顺利拆除外固定,颧弓切线位X线复查提示骨折对位良好,骨折线模糊,无术后感染。结论 自制面模具作为颧弓骨折复位术后的外牵引辅助治疗,可以较好地预防并发症发生。     

不同比重布比卡因连续腰麻对老年髋关节手术平面可控性的影响

目的 比较不同比重布比卡因对老年髋关节手术平面可控性的影响。方法 将54例接受髋关节置换术的老年患者分为观察组与对照组（均为n=27）,于蛛网膜下腔分别注射轻比重及等比重布比卡因,比较注射前及维持麻醉所需可控平面时的生命征,比较两组布比卡因用量、感觉既运动阻滞起效及维持时间,可控平面位置及Bromage分级。结果 ①两组患者的一般情况以及注药前的生命征无统计学差异,且术后无出现马尾综合征等并发症;②生命征方面,当麻醉平面达T8~T10时,两组患者的收缩压均显著低于注药前,且对照组的收缩压及平均动脉压低于观察组（P<0.05）;③麻醉效果方面,观察组的布比卡因用量显著低于对照组(P=0.029);观察组的感觉及运动阻滞起效时间显著短于对照组(P=0.032、0.027),且观察组的麻醉维持时间显著长于对照组(P=0.042),但两组患者的麻醉可控平面无统计学差异（P=0.162）。结论 轻比重及等比重布比卡因在老年髋关节手术平面可控性均较理想,但轻比重布比卡因对血压的影响及用量更小,且麻醉效果优于等比重布比卡因。