对比因素对儿童分辨物体细节能力的影响

目的观察对比因素对儿童分辨物体细节能力的影响,了解儿童对比视力的状况。方法使用对比视力表,测量53名裸眼视力≥5.0的正常儿童92%,52%,30%对比水平处的对比视力。结果儿童的对比视力随对比度的降低而显著下降,对比度与视力之间存在显著相关;左、右眼的对比视力差异无统计学意义;男性和女性的对比视力差异无统计学意义。结论低对比的学习环境会增加儿童视觉负荷,在防治学生近视过程中应引起重视。     

小鼠外周血白细胞节律相关基因cry2,per2,timeless,rev-erb表达的近日节律性研究

目的探讨在12 h光照/12 h黑暗（12L/12D）光暗循环条件下,小鼠外周血白细胞中相关基因cry2,per2,timeless,rev-erb近日节律性表达特点。方法用完全随机分组法将C57/BL6小鼠分成6组,每组对应一个时相点,在12L/12D条件下词养4周后分别在6个时相点（9：00,13：00,17：00,21：00,1：00,5：00）取外周血并分离白细胞。抽提总RNA,采用实时荧光定量PCR技术检测小鼠外周血白细胞cry2,per2,timeless,rev-erb 4种节律基因的mRNA水平,用余弦函数拟合节律参数,并经振幅f检验分析是否存在近日节律。结果 cry2,per2,timeless,rev-erb 4种基因mRNA存在明显的近日节律性,各基因的峰值明显高于谷值（P〈0.01）;per2峰值相位时间在4：00左右,而cry2,timeless,rev-erb基因的峰值时间在11：00-12：00;从峰值时间和震荡幅度看,cry2,timeless,rev-erb峰值时间比per2超前,振幅比per2高,cry2、timeless、rev-erb的峰值时间、振幅大小比较接近。结论 C57/BL6小鼠外周血白细胞4种基因cry2,per2,timeless,rev-erb的mRNA存在明显的近日节律性。cry2,timeless,rev-erb在负反馈中的作用强于per2,而cry2,timeless,rev-erb在负反馈中的作用相似。该研究为深入理解哺乳动物的免疫功能昼夜波动打下了基础,也为诊断、治疗免疫功能紊乱相关疾病提供了靶目标。但这4种基因如何调控外周血中的免疫细胞,尚需进一步深入研究。     

沙土鼠急性脑缺血再灌注和高压氧作用后软脑膜微循环的改变

目的:研究沙土鼠脑缺血后经不同氧压高压氧治疗后软脑膜微循环改变。方法:用激光显微血流计对微血管管径和微血流速度进行了定量测定。结果:脑缺血后微血管血流速度明显减慢,管径开始一过性收缩。以后逐渐扩张。单纯再灌注后,血流速度仍明显低于缺血前,血管明显扩张。经高压氧治疗后,可使微血流加速,血管收缩,清除血管内微小血栓.改善微循环;但对血管管径作用是一过性的。结论:高压氧具有改善缺血组织微循环的作用。     

长期视远剥夺对人眼集合近点和调节近点的影响

Objective To study effects of sustained deprivation of far sight on human near point of convergence (NPC) and near point of accommodation (NPA). Methods Eight subjects were divided into two groups by age (group A ≥30 years old; group B<30 years old). All subjects had worked in the enclosed laboratory, unable to see the outside for 75 days. NPC and NPA were measured every 15 days. Results NPC values of both groups all increased when time elapsed. NPC of group A measured in the 75th day and NPC of group B in the 30th day all had statistical differences, when compared with the base NPC values measured in the 15th day (P<0.05). And NPC value of group B measured in the 45th, 60th and 75th days increased markedly, when compared with that of the 15th day (P<0.01 . However, statistical analysis showed that no significant difference could be seen in NPA values of the two groups (P>0.05). Conclusions Sustained deprivation of far sight could induce an increase in NPC values to various degreeal, but effects on NPA were not obvious, as noted in our experiment.     

长期视远剥夺对人眼集合近点和调节近点的影响

Objective To study effects of sustained deprivation of far sight on human near point of convergence (NPC) and near point of accommodation (NPA). Methods Eight subjects were divided into two groups by age (group A ≥30 years old; group B<30 years old). All subjects had worked in the enclosed laboratory, unable to see the outside for 75 days. NPC and NPA were measured every 15 days. Results NPC values of both groups all increased when time elapsed. NPC of group A measured in the 75th day and NPC of group B in the 30th day all had statistical differences, when compared with the base NPC values measured in the 15th day (P<0.05). And NPC value of group B measured in the 45th, 60th and 75th days increased markedly, when compared with that of the 15th day (P<0.01 . However, statistical analysis showed that no significant difference could be seen in NPA values of the two groups (P>0.05). Conclusions Sustained deprivation of far sight could induce an increase in NPC values to various degreeal, but effects on NPA were not obvious, as noted in our experiment.     

长期视远剥夺对人眼集合近点和调节近点的影响

Objective To study effects of sustained deprivation of far sight on human near point of convergence (NPC) and near point of accommodation (NPA). Methods Eight subjects were divided into two groups by age (group A ≥30 years old; group B<30 years old). All subjects had worked in the enclosed laboratory, unable to see the outside for 75 days. NPC and NPA were measured every 15 days. Results NPC values of both groups all increased when time elapsed. NPC of group A measured in the 75th day and NPC of group B in the 30th day all had statistical differences, when compared with the base NPC values measured in the 15th day (P<0.05). And NPC value of group B measured in the 45th, 60th and 75th days increased markedly, when compared with that of the 15th day (P<0.01 . However, statistical analysis showed that no significant difference could be seen in NPA values of the two groups (P>0.05). Conclusions Sustained deprivation of far sight could induce an increase in NPC values to various degreeal, but effects on NPA were not obvious, as noted in our experiment.     

海军飞行员对不同对比度运动目标的视觉识别效能研究

目的　探讨在模拟客观的视觉环境中海军飞行员对不同对比度运动目标的识别效能 ,为保障在不同能见度条件下的安全飞行提供科学依据。方法　用自行研制的视觉运动目标作业效能测试系统 ,检测 31名海军飞行员对不同对比度连续运动目标的发现和辨认效能 ,记录其反应时、辨认距离和正确率。结果　随着对比度的增高 ,对运动目标的发现时间缩短 (P<0 .0 1) ,发现距离延长 (P<0 .0 1) ;对运动目标辨认的反应时间缩短 ,正确率增加 ,识别距离延长。对比度由 3%增加到 30 % ,各项指标变化幅度较大 (P<0 .0 1)。结论　检测对不同对比度运动目标的视觉作业效能是评价海军飞行员视工效的有效方法。     

高压氧对沙土鼠脑缺血再灌注海马神经细胞NMDA受体的作用研究

显,但显著高于假手术组(P<0.01).结论 脑缺血后,海马区神经细胞NMDA受体的Bmax显著增加,氯胺酮、氯胺酮+高压氧治疗可使Bmax降低.可能通过此途径减少细胞外Ca2+内流,恢复细胞内游离Ca2+浓度,从而起到高压氧治疗脑缺血的作用.     

白大衣高血压患者动态脉压及脉压指数的特征分析

目的 分析白大衣高血压(WCH)患者动态脉压(APP)及动态脉压指数(APPI)的特征,探讨WCH对血管硬化的影响.方法 WCH患者60例、高血压I级患者60例(高血压组)和血压正常者50名(对照组)入选本研究,测量其诊室血压和动态血压,对各组APP及APPI进行组间比较.结果 WCH组和高血压组患者的诊室脉压及脉压指数高于对照组(P＜0.01),且WCH组高于高血压组(P＜0.01);高血压组患者24 h APP大于WCH组和对照组(P＜0.01),WCH组患者的白天动态脉压(dAPP)大于对照组(P＜0.01),高血压组患者24 h APPI、白天APPI(dAPPI)和夜间APPI(nAPPI)均大于WCH组和对照组(P＜0.01),WCH组24 h APPI、dAPPI和nAPPI亦均大于对照组(P＜0.05).结论 WCH不同于正常人群,会对血管造成一定程度的损伤,引起血管硬化,但其危害程度小于高血压,造成的损伤作用白天更明显.     

微波在临床治疗上的应用进展

微波是指频率在300 MHz～300 GHz,在空气中波长为1 m～1 mm的电磁波.微波治疗是常用的超高频治疗方法之一,已被广泛应用于临床.目前常用的是915 MHz与2 450 MHz微波,其中以2 450 MHz微波最为常用.现对微波在临床治疗上的应用作简单综述.