微波辐射损伤及防护研究进展

随着微波技术广泛应用于通讯、广播、工业电器设备、医疗及家用电器等,其可能带来的生物危害及环境污染越来越引起人们的重视。对微波辐射生物学效应、机制和防护研究已成为各国学者的研究热点且已取得一定进展。本文就微波辐射对生物体健康的影响、生物效应机制及辐射防护进展作一综述。     

产后抑郁症的MRI研究进展

产后抑郁症（PPD）为常见的产后精神障碍,其发病机制尚不清楚。基于体素的形态学分析、基于表面的形态学测量、扩散张量成像、扩散峰度成像、血氧水平依赖功能MRI、MR波谱成像等多种MRI技术已广泛用于探究PPD病人的脑结构、功能和代谢中发生的异常改变,这些技术使得明确PPD的神经生物学机制成为可能,也可为该病的早期诊断和预后判断提供客观的影像依据。就MRI在PPD中的影像学研究进展予以综述。     

微波辐射防护剂研究现状

随着微波（频率300MHz～300GHz）技术的发展,微波在通讯、家用电器、工业和军事等领域应用越来越广泛,人受微波辐射的机会越来越多,微波对健康影响开始引起人们的重视,微波的生物损伤效应研究成为热点。近年来大量研究工作表明,微波可对生物体造成不同伤害。     

微波辐照对神经认知、免疫功能影响的研究进展及展望

有关电磁辐射的研究以往主要集中在对电子仪器的影响和危害方面,而对生物体健康影响的报道很少.虽然射频辐射对人体健康影响的研究最早可追溯到20世纪50年代,但是微波作为射频辐射的一种,对生物体影响的研究近十几年才受到重视.目前,微波辐照对神经认知、免疫功能的影响是微波生物效应领域的重点研究内容之一.本文主要针对近年来微波辐射对其敏感的靶器官-神经系统、免疫系统影响的研究进展及其可能的机制作一概述,以期为同行领域的研究者提供借鉴与参考.     

生物医学光学(诊断与治疗)新技术的研究

通过对生物医学光学中理论基础和技术重点的学习和研究,清晰生物医学光学具体范畴及相互交叉学科相互关联和应用、发展方向。更好地解决从宏观到微观多层面上对研究生物体特别是人体的结构、功能和生命现象、疾病探测、诊断和治疗提供理论依据,寻找热点问题与发展趋势。生物医疗光学是光学与生命科学互相交叉的学科,包括生物光子学和医学光子学两部分。医学光子学的基础和技术,包括组织光学、医学光谱技术、医学成像术的研究。生物光子学是以研究生物体辐射的光子特性来研究生物体自身的功能和特性的学科。生物光子学在临床诊断、农作物遗传性诊断及环境检测等领域有重要的应用,主要包括生物系统的诱导发光、激光扫描共焦显微技术、光学相干断层扫描(Optical coherence tomography,OCT)、光学光钳等技术的研究。现代医学正由传统的基于症状治疗模式向以信息为依据的治疗模式转变,生物医学光学为医学诊断与治疗提供了更多、更有效的手段。生物光子学在医学治疗方面的技术应用广泛,主要应用包括:光动力疗法(photodynamic therapy,PDT)、激光在牙科、美容、眼科应用及其他应用。生物医学光学是新兴的学科,为揭示生命活动的基本规律、临床医学诊断与治疗提供了新的技术手段和方法。随着生物医学光学研究的进一步深入,也展现了一些亟待解决的问题。光学层析成像及光谱学技术的理论与模型、生物组织的光学成像和用于生物监测的光谱学技术、生物医学和临床的相干域光学方法、生物光谱学和显微术、激光与生物组织的相互作用,这些方面的问题成为研究热点问题与发展趋势,都需要加强研究。     

舰船核辐射医学防护技术与装备研究进展

舰艇核辐射医学防护技术与装备,主要包括核辐射监测技术与装备、核辐射防护技术与装备、小剂量辐射生物效应及防护技术、核辐射损伤伤员的医学监测及药物防治等。     

国外海军医学动态系列讲座(12)舰船核辐射医学防护技术与装备研究进展

舰艇核辐射医学防护技术与装备,主要包括核辐射监测技术与装备、核辐射防护技术与装备、小剂量辐射生物效应及防护技术、核辐射损伤伤员的医学监测及药物防治等.     

肝性脑病楔前叶的影像学研究进展

肝性脑病(HE)是一种可逆性神经精神异常综合征,发病率较高。目前关于HE诊断的相关研究主要致力于寻找神经系统异常的生物标志物。采用多种功能成像技术可以观察到HE病人楔前叶（PC）存在结构、功能等异常,且PC的异常程度与HE病人临床表现、认知功能测试结果及生化指标密切相关。就静息态功能MRI（rs-fMRI)、扩散张量成像（DTI）、MR波谱成像（MRS）等成像技术对HE病人PC的改变及其特点的研究进行综述。     

微波辐射对动物本能行为学影响技术方法的建立

目的运用生物特征识别技术建立微波辐射对动物本能行为学影响的新技术方法。方法 Wistar大鼠9只,猕猴9只,观察微波辐射前后动物的活动情况,包括抬头、晃动、转身等累积运动时间,进行生物特征识别判断。结果比较距微波辐射源不同距离的猕猴和大鼠在微波辐射后活动度,包括抬头和晃动的累积运动时间有所变化,其余观察指标未见异常。结论此方法可适时监测微波辐射对动物本能行为学的影响,值得推广应用。     

乳腺良恶性病变的MRI多模态灌注成像研究进展

MRI具有多参数、多方向、无辐射、高软组织分辨力等优点,已成为乳腺成像的重要手段。PWI是一种可以反映组织或微血管病变分布和血流灌注效应的MRI技术,能够间接反映肿瘤血管的功能状态,对研究肿瘤血供具有极高的价值。其中,T_1灌注成像、T_2灌注成像、动脉自旋标记技术(ASL)及DWI均可以在体内无创评价肿瘤组织的血管生成及灌注情况,提供血流动力学方面信息,为乳腺病变的进一步诊断和治疗提供可靠依据。现对乳腺MRI灌注成像的不同技术及其临床应用综述如下。     

Theoretical basis for long-term measurements of equilibrium factors using LR 115 detectors

In this paper, we propose a method to determine the equilibrium factor using a bare LR 115 detector. The partial sensitivities ρ_i of the LR 115 detector to ²²²Rn and its alpha-emitting short-lived progeny, ²¹⁸Po and ²¹⁴Po, were investigated. We first determined the distributions of lengths of major and minor axes of the perforated alpha tracks in the LR 115 detector produced by ²²²Rn, ²¹⁸Po and ²¹⁴Po through Monte Carlo simulations. The track parameters were calculated using a track development model with a published V function, by assuming a removed active layer of 6.54 μm. The distributions determined for different alpha emitters were found to completely overlap with one another. This implied equality of partial sensitivities for radon and its progeny, which was also confirmed through analytical considerations. Equality of partial sensitivities makes possible convenient measurements of the proxy equilibrium factor F_p, which is defined in the present work as (F₁+F₃) and is equal to the ratio between the sum of concentrations of the two alpha emitting radon progeny (²¹⁸Po+²¹⁴Po) to the concentration of radon gas (²²²Rn). In particular, we have found F_p=(ρ/ρ_itC₀)−1, where ρ (track/m²) is the total track density on the detector, ρ_i=0.288×10⁻² m, t is the exposure time and C₀ (Bq/m³) is the concentration of ²²²Rn. If C₀ is known (e.g. from a separate measurement), we can obtain F_p. The proxy equilibrium factor F_p is also found to be well correlated with the equilibrium factor between radon gas and its progeny through the Jacobi room model. This leads to a novel method for long-term determination of the equilibrium factor.     

Influence of a TcN core on the biological and physicochemical behavior of Tc complexes of L,L-EC and L,L-ECD

^99mTc-nitrido complexes of L,L-ethylene dicysteine (^99mTcN-L,L-EC) and ^99mTcN-L,L-ethylene dicysteine diethylester (^99mTcN-L,L-ECD) were prepared and their characteristics compared to those of the respective ^99mTc-oxo complexes. ^99mTcN-L,L-EC and ^99mTcO-L,L-EC migrate to similar extents during electrophoresis at pH 12, but, at pH 6, ^99mTcN-L,L-EC migrates further than ^99mTcO-L,L-EC. Renal excretion of ^99mTcN-L,L-EC is inferior to that of ^99mTcO-L,L-EC, indicating that the TcN-glycine sequence has lower affinity for the renal tubular system. Both ^99mTcO-L,L-ECD and ^99mTcN-L,L-ECD are neutral, but ^99mTcN-L,L-ECD is hydrophilic and shows minimal brain uptake in both mice and the baboon.     

Effects of increased ventilation and improved pulmonary gas-exchange on maximal oxygen uptake and power output

Recent reports suggest that aerobic performance at very high levels may be limited by the pulmonary system. The purpose of the present study was to compare respiratory functions at rest and during graded maximal aerobic exercise (cycle ergometry) between well-trained (TR, n = 11) and untrained (UT, n = 14) individuals while breathing atmospheric air, normoxic helium (He) and oxygen-enriched mixture. When the subjects breathed air, TR exhibited lower exercise ventilatory reserve (MVV-VE_max), ratio between minute ventilation (VE) and oxygen uptake (V_o2) and SaO₂ than UT. Breathing HE resulted in an increase in VE and V_o2max in both groups but in an increased VE/V_o2 and SaO₂ and maximal mechanical cycle ergometer load, only in TR. Compared with air, breathing an oxygen-enriched mixture resulted in increased peak exercise SaO₂ and maximal mechanical load in both groups. It is concluded that arterial O₂ desaturation secondary to a relative hypoventilatory response may limit V_o2max and aerobic performance capacity at high work levels.     

Assessment of the skeletal status by MR relaxometry techniques of the lumbar spine: comparison with dual X-ray absorptiometry

Purpose: To measure lumbar spine T2*, T2, T2′ and T1 MR relaxometry parameters and compare them with lumbar spine bone mineral density (BMD) in a group of postmenopausal women. Materials and methods: Lumbar spine T2*, T2, T2′ and T1 MR relaxometry parameters and BMD values were assessed in 101 postmenopausal women (mean age: 61.8±7.1 (1 S.D.) years); of them 63 referred to as control subjects (group A, BMD T-scores ≥ −2.5 S.D.) and 38 as osteoporotic (group B, BMD T-scores < −2.5 S.D.). All magnetic resonance imaging (MRI) examinations were performed on an 1.5 T imaging system using: (a) a 2D single slice multi echo (32 echoes) gradient echo (MEGRE) sequence (TR/TE1/TE32/FA: 160/2.7/74.93 ms/25°) for the T2* measurement, (b) a respiratory gated 2D single slice Multi Echo (16 echoes) Spin Echo (MESE) sequence (TR/TE1/TE16/FA: 2000–2500/22.5/360 ms/90°) for the T2 measurement and (c) a 2D single slice multi TI (18 repeats) turbo Fast Low Angle Shot (turbo FLASH) sequence (TR/TE/TI1/TI16/FA: 11/4.2/10/5000 ms/10°) for the T1 measurement. T2′ was calculated from its definition equation: (1/T2′ = 1/T2* − 1/T2). Lumbar spine BMD was assessed using DXA. Results: All measured parameters showed statistically significant differences between groups A and B (from P<0.05 to <0.001). All parameters showed significant associations with subject’s age ranging from r=0.245 (P<0.05) for the T2 up to r=0.377 (P<0.001) for the T2*. All parameters showed significant associations with subject’s BMD measurements ranging from r=−0.184 (P<0.05) for the R1 = (1/T1) up to r=−0.345 (P<0.0005) for the T2. Conclusion: Among the MR relaxometry parameters studied, T2* and T2 showed better discrimination of patients with osteoporosis from control subjects.     

Maximal oxygen uptake as a predictor of performance ability in women and men elite cross-country skiers

Maximal oxygen uptake (O_2max) was measured in 51 females and males classified as either world-class, medium-class or less successful elite skiers. The O_2max in the male world-class skiers was significantly higher (mean 85.6 ml·kg⁻¹·min⁻¹ or 355 ml·min⁻¹ kg⁻²³) than in the other elite skiers. World-class and medium-class female skiers had identical mean O_2max expressed in ml·kg⁻¹·min⁻¹ (70.7 and 70.6, respectively), but the values differed significantly when the unit ml·min⁻¹kg^−2/3 was used (274 and 264, respectively). O_2max expressed as ml·min⁻¹·kg^−2/3 reflects differences in performance capability among elite skiers better than the unit ml·kg⁻¹·min⁻¹.     

A comparative study of 188Re(V)-meso-DMSA and 188Re(V)-rac-DMSA: preparation and in vivo evaluation in nude mice xenografted with a neuroendocrine tumor

Dimercaptosuccinic acid (DMSA) exists in meso and racemic (rac) forms. Unlike a meso isomer, rac-2,3-DMSA is very soluble in water, strongly acidic solutions and organic solvents. Despite these differences, rac-2,3-DMSA has not been studied as a radiopharmaceutical. In this study, ¹⁸⁸Re complexes with diastereomeric DMSA were prepared to compare the properties of ¹⁸⁸Re(V)-rac-DMSA with those of ¹⁸⁸Re(V)-meso-DMSA in in vitro and in vivo models.

Methods

rac-2,3-DMSA was synthesized and radiolabeled with ¹⁸⁸Re. The biodistribution and gamma camera imaging of ¹⁸⁸Re(V)-meso-DMSA and ¹⁸⁸Re(V)-rac-DMSA were performed in nude mice subcutaneously implanted with PC-12 cell lines.

Results and conclusions

Both ¹⁸⁸Re(V)-meso-DMSA and ¹⁸⁸Re(V)-rac-DMSA showed excellent radiochemical purity and stability at room temperature. Compared with ¹⁸⁸Re(V)-meso-DMSA, ¹⁸⁸Re(V)-rac-DMSA needed a higher concentration of rac-DMSA and metabisulfite for maximum yields. ¹⁸⁸Re(V)-meso-DMSA showed high labeling efficiency at pH 2, whereas ¹⁸⁸Re(V)-rac-DMSA showed maximum yields at pH 5. The tumor uptake of ¹⁸⁸Re(V)-rac-DMSA was 3.5 times higher than that of ¹⁸⁸Re(V)-meso-DMSA at 1 h (P<.01). Gamma camera images showed that ¹⁸⁸Re(V)-rac-DMSA was more selectively localized than ¹⁸⁸Re(V)-meso-DMSA at the tumor region in a xenograft model. These results demonstrate that ¹⁸⁸Re(V)-rac-DMSA may have better potential than ¹⁸⁸Re(V)-meso-DMSA as a therapeutic agent against neuroendocrine tumors.