不同功率半导体激光照射对大鼠神经电生理功能恢复的影响

研究不同功率的半导体激光照射对大鼠损伤神经电生理功能恢复的影响。结果：１５ｍＷ的半导体激光照射可促进神经纤维的再生过程,第６、８周时激光组的运动神经传导速度明显高于对照组,而５ｍＷ和１０ｍＷ半导体激光照射组与对照组比较无明显差异。结论：１５ｍＷ半导体激光照射大鼠２的坐骨神经,有促进损伤神经功能恢复的作用。     

激光照射对急性脊髓损伤后脊髓再生的促进作用

建立大鼠皮质脊髓背侧束全横断模型,利用弱激光照射脊髓受损部位的皮肤,观察激光照射对急性脊髓损伤后脊髓再生的促进作用.30只SD大鼠,随机分成对照组和照射组.照射组:急性皮质脊髓背侧束全横断后15 min进行连续14 d采用弱激光照射脊髓受损部位的皮肤.对照组:急性皮质脊髓背侧束全横断后未行弱激光经皮照射治疗.术后两组分别于第3,7,14 d分别取材,用苏木精-伊红染色法(HE)染色和免疫荧光标记染色观察.实验发现,脊髓损伤后14 d,照射组的空洞及瘢痕形成面积小于对照组,有统计学差异(p<0.05);对照神经胶质酸性组蛋白(GFAP)和硫酸软骨素(CS)表达强烈分布紧密,照射组GFAP和CS56表达达微弱且分布稀疏;对照组少量神经微丝蛋白(NF)在损伤区周围,神经生长相关蛋白(GAP43)形态肿大变形分布紊乱,照射组大量成纤维丝状的NF分布在损伤区周围,并与GAP43相伴行.结果表明,脊髓损伤急性期采用弱激光照射脊髓受损部位的皮肤,可减少脊髓损伤后空洞形成,并促进轴突再生.     

He-Ne激光对小白鼠周围神经再生影响的实验研究

用He-Ne激光照射小白鼠,对其损伤的坐骨神经再生有促进作用,且以直接照射脊髓段促进神经再生作用最强.     

氦氖激光照射对大鼠实验性牙移动牙周组织中环氧化酶-2表达的影响

为探讨氦氖激光局部照射调控正畸牙移动过程中血管改建的机制,应用波长为632.8nm,激光功率为20mW的氦氖激光照射实验性牙移动大鼠的牙周组织,进而对牙周组织切片进行环氧化酶-2(COX-2)免疫组织化学染色。图像分析结果显示压力区加力3、5、7d组照射侧牙周组织COX-2表达明显高于对照侧,14d后照射侧与对照侧差异无统计学意义;张力区加力1、3、5、7d组照射侧COX-2表达均明显高于对照侧,差异有统计学意义。结果表示氦氖激光照射能增强实验性牙移动大鼠牙周组织中COX-2的表达,参与促进正畸牙移动血管改建的进程。     

大剂量He－Ne激光照射剂量与部位筛选试验

应用不同剂量的Ｈｅ－Ｎｅ激光照射大鼠机体不同部位，筛选出了方便而效果明显的照射部位与剂量，即以３９．７２Ｊ／ｃｍ￣２的Ｈｅ－Ｎｅ激光照射大鼠脊背正中线皮肤，连续１４天，可产生明显的免疫抑制作用。     

大剂量He—Ne激光照射剂量与部位筛选试验

应用不同剂量的Ｈｅ－Ｎｅ激光照射大鼠机体不同部位，筛选出了方便而效果明显的照射部位与剂量，即以３９．７２Ｊ／ｃｍ＾２的Ｈｅ－Ｎｅ激光照射大鼠脊背正中线皮肤，连续１１４天，可产生明显的免疫抑制作用。     

激光照射对脊髓损伤大鼠TNF-α、IL-6和IL-10表达的影响

应用Allen造模法制备大鼠急性脊髓损伤(SCI)模型,研究弱激光照射对损伤脊髓组织内肿瘤坏死因子α(TNF-α)、白介素-6(IL-6)和白介素-10(IL-10)表达的影响。68只SD大鼠随机分为正常组、SCI组和照射组,照射组应用810nm弱激光经皮照射相应的脊髓损伤节段。分别于术后1d、3d和7d进行BBB评分;1h、3h、6h、12h、1d、3d、5d和7d取材,酶联免疫吸附检测(ELISA)法检测受损脊髓组织内TNF-α、IL-6和IL-10的表达情况。实验发现,照射后7d照射组大鼠BBB评分高于SCI组,且有统计学意义(P0.05);与SCI组相比,照射组受损脊髓组织内TNF-α和IL-6的表达量均降低,且在术后6h、12h、1d(TNF-α)和6h、12h、5d(IL-6)差异有统计学意义(P0.05);IL-10的表达量在各个时间点均增高,且在术后1d、3d、5d和7d差异有统计学意义(P0.05)。结果表明弱激光照射能明显抑制脊髓损伤早期前炎症因子TNF-α和IL-6的表达,促进抑炎因子IL-10的表达,促进损伤后期大鼠运动功能的恢复。     

紫外激光对眼和皮肤的照射装置及损伤阈值研究

本文介绍266nm,355nm激光照射兔眼、人前臂屈侧皮肤及白色幼猪皮肤损伤阈值研究的照射装置、方法与结果。     

低强度激光照射对视网膜谷氨酸受体表达的影响

目的: 探讨低强度激光致视网膜损伤效应的可能机制。方法: 建立氦氖激光的大鼠眼损伤模型, 通过免疫组化和原位杂交等方法, 观察低强度激光照射后视网膜细胞中谷氨酸受体(NMDAR)的表达变化。结果: 免疫组化和原位杂交的结果显示在正常视网膜组织未见或仅见有NMDAR的轻微表达, 而在激光照射后6 h其表达开始增加, 并于照后3 d达到高峰, 7 d后开始逐渐下降, 这与视网膜激光损伤后感光神经元的凋亡在时相上呈现出一致性。结论: 低强度激光照射后视网膜局部谷氨酸的过度释放及NMDAR受体的高表达可能是感光神经元损伤凋亡的重要机制。     

CO_2激光对黄种人皮肤急性损伤阈值的研究

本文主要叙述了CO_2激光照射系统的监测工作.对8只小白猪皮肤受CO_2激光照射的急性损伤阈值(MRD_(50))进行了测定.在此基础上,对6位志愿者的前臂屈侧皮肤进行了受CO_2激光照射后的急性损伤阈值测定,其值为2.3J/cm~2.用该能量密度照射后皮肤的组织学检查,发现其所引起的反应是最小反应,是可逆的.     

半导体绿色激光穴位照射对大鼠神经损伤后神经再生的影响

周围神经损伤后提高神经功能恢复是临床治疗的目的.本实验利用大鼠坐骨神经钳夹损伤模型,用半导体绿色激光533nm(A组)、He-Ne激光632.8nm(B组)对穴位照射.观察对神经损伤后神经再生的影响.结果:(1)术后18d,A组可引出短潜伏期(45～150ms)及长潜伏期(125～525ms)神经传入纤维反应高于B组;(2)术后18d脊神经节的标记细胞百分率分别为12.9%(A组)、10.2%B(组).上述结果表明:半导体绿色激光在抑制神经损伤后促进周围神经再生等方面具有更显著的生理功效.     

Magnetic stimulation of curved nerves

Magnetic stimulation of nerves is attracting increased attention recently, as it has been found to be useful in therapy of neural disorders in humans. In an effort to explain the mechanisms of magnetic stimulation, we focus in this paper on the dependence of magnetic stimulation on neuronal morphology and in particular on the importance of curvature of axonal bundles. Using the theory of passive membrane dynamics, we predict the threshold power (the minimum stimulation power required to initiate an action potential) of specific axonal morphologies. In the experimental section, we show that magnetic stimulation of the frog sciatic nerve follows our theoretical predictions. Furthermore, the voltage length constant of the nerve can be measured based on these results alone.     

变化的半导体激光对周围神经损伤的研究

目的:探讨低功率半导体激光对家兔神经功能恢复的影响。方法用56只家兔随机分为4,8,12和16周4个观察期组,每个观察期组随机分为强度按一定规律变化的半导体激光照射A组(各用家兔5只)、半导体激光照射B组(各用家兔5只)和对照组(各用家兔4只)。麻醉后,均切断左侧腓总神经,用9/0尼龙单丝对端吻合神经外膜。各照射组在术后1d开始照射家兔L5,6脊髓节段,激光功率为2mW,A组在激光输出端加以100Hz旋转的偏振片,每天照射5min,连续照射7d。对照组不照射,均按期观察。结果术后4周,各照射组看到细小、稀少的再生轴突,对照组12周才看到(P<0.01),A组优于B组(P<0.05);各照射组腓总神经潜伏速率和动作电位波幅均优于对照组(P<0.01),A组优于B组(P<0.05)。展趾功能到术后16周,A组与侧健相同,B组恢复到A组12周的水平,对照组恢复到A组近8周的水平。结论低功率强度按一定规律变化的激光能促进脊髓运动细胞功能,加速轴突再生。     

低功率半导体激光照射对神经功能恢复的影响

目的探讨低功率半导体激光对家兔神经功能恢复的影响。方法用 36只体重 2 .5kg左右的家兔随机分为 3,6 ,9和 12周 4个观察期组 ,每个观察期组随机分为半导体激光照射组 (各用家兔 5只 )和对照组 (各用家兔 4只 )。麻醉后 ,均切断左侧腓总神经 ,用 9/0尼龙单丝对端吻合神经外膜。各照射组在术后 1d开始照射家兔L5 ,6脊髓节段 ,照射激光输出功率为2mW ,每天照射 5min ,连续照射 7d。对照组不照射 ,均按期观察。结果术后 3周 ,可在照射组看到细小而稀少的再生轴突 ,对照组直到术后 6周才看到 (P <0 .0 1)。照射组的腓总神经潜伏速率均优于对照组 (P <0 .0 1) ,动作电位波幅照射组也优于对照组。展趾功能到术后 12周 ,照射组与侧健相同 ,对照组才恢复到照射组 6周的水平。结论低功率的半导体激光促进脊髓运动神经细胞功能 ,加速轴突再生     

Characteristics of Somatosensory Evoked Potentials Recorded over the Spinal Cord and Brain of Man

Evoked potentials were recorded from the skin over the lumbar and cervical portions of the spinal cord, and the scalp over the sensory cortex of the brain, using averaging techniques. Responses could be identified over the cauda equina and root entry zone in the lumbar spine to stimulation of the tibial nerve at the popliteal fossa. These responses had characteristics of nerve root and spinal cord events in their thresholds, timing, duration, and refractoriness. Stimulation of the median nerve at the wrist likewise resulted in recognizable responses over root entry portions of the cervical spinal cord. These later waves had a morphology suggestive of components arising from nerve plexus, nerve roots, and spinal cord. Responses recorded over the spinal cord were in the 1-10 ?V amplitude range. Tibial, peroneal and median nerve stimulation were used to elicit 1-20 ?V responses recorded over the cortex, which were found to be sensitive to the site, amplitude, and rate of stimulation.     

Selective stimulation of peripheral nerve fibers using dualintrafascicular electrodes

The authors have studied activation of nerve fibers by pairs of Pt-Ir wire electrodes implanted within single fascicles of the nerve innervating the gastrocnemius muscle in cats. The purpose of this study was to determine if these intrafascicular electrodes can activate nerve fibers in different fascicles independently of each other and if they can also be used to activate separate subsets of axonal populations within a single fascicle. The average overlap of activated nerve fiber populations was 5.5% between fascicles and 27% within a fascicle, indicating that such selective activation is possible with these electrodes     

Techno-economic considerations in the commercial microwave processing of mineral ores.

Microwave heating of mineral ores had previously been shown to result in process benefits such as reduced strength and improved mineral liberation, but the economics of the process were not attractive and no attention was given to feasible scale-up. This paper provides an overview of the multi-disciplinary approach that has been required to address these failings and develop the technology to pilot scale. Thermal stress simulations show that the operation at high power densities and short residence times is the optimal operating strategy. Experiments using high power densities (approximately 10(9) W/m3 absorbing phase) and short residence times (approximately 0.1 s) were used to confirm that the benefits can now be achieved at economically viable microwave energy inputs (approximately 1 kWh/t). In order to design applicators, reliable measurement of effective microwave properties of crushed ores is required. A method has been developed to extract dielectric properties when the sample thickness is a multiple of half a guide wavelength at some point in the measurement band. Finite difference time domain modeling has been used to design and simulate applicators. A transverse E field applicator with a reflection compensating step has been developed, and a unit with a capacity of > 10 tons/h is being tested. Preliminary economic analysis shows that the overall cost of the process will be between US $0.16 - 0.85 per ton of ore.     

磁作用半导体激光照射对神经功能恢复的影响

探讨了磁作用半导体激光对家兔神经功能恢复的影响.将家兔随机分为3周,6周,9周和12周4个观察期,每个观察期随机分为磁作用激光照射组、激光照射组和对照组.麻醉后,均切断左侧腓总神经,用9/0尼龙单丝对端吻合神经外膜.各照射组在术后1d开始照射家兔L5,L6脊髓节段,每天照射5min,连续照射7d.对照组不照射,均按期观察.术后3周,各照射组看到细小而稀少的再生轴突,磁作用激光组优于激光组和对照组;各照射组的腓总神经潜伏速率和动作电位波幅均优于对照组,磁作用激光组优于激光组.展趾功能到术后12周,磁作用激光组与右侧相同,激光组和对照组分别恢复到磁作用组9周和6周水平.低功率的磁半导体激光促进了脊髓运动神经细胞功能的恢复,加速了轴突再生.     

Selective activation of small motor axons by quasitrapezoidalcurrent pulses

We have found a method to activate electrically smaller nerve fibers without activating larger fibers in the same nerve trunk. The method takes advantage of the fact that action potentials are blocked with less membrane hyperpolarization in larger fibers than in smaller fibers. In our nerve stimulation system, quasitrapezoidal-shaped current pulses were delivered through a tripolar cuff electrode to effect differential block by membrane hyperpolarization. The quasitrapezoidal-shaped pulses with a square leading edge, a 350 microsecond(s) plateau, and an exponential trailing phase ensured the block of propagating action potentials and prevented the occurrence of anodal break excitation. The tripolar cuff electrode design restricted current flow inside the cuff and thus eliminated the undesired nerve stimulation due to a "virtual cathode." Experiments were performed on 13 cats. The cuff electrode was placed on the medial gastrocnemius nerve. Both compound and single fiber action potentials were recorded from L7 ventral root filaments. The results demonstrated that larger alpha motor axons could be blocked at lower current levels than smaller alpha motor axons, and that all alpha fibers could be blocked at lower current levels than gamma fibers. A statistical analysis indicated that the blocking threshold was correlated with the axonal conduction velocity or fiber diameter. This method could be used in physiological experiments and neural prostheses to achieve a small-to-large recruitment order in motor or sensory systems.     

低功率磁作用半导体激光照射对神经功能恢复的影响

目的 :探讨低功率磁作用半导体激光对家兔神经功能恢复的影响。方法 :用 5 6只体重 2 .5kg左右的家兔随机分为 3 ,6,9和 12周 4个观察期组 ,每个观察期组随机分为半导体激光照组 (各用家兔 5只 )、磁作用半导体激光照组 (各用家兔 5只 )和对照组 (各用家兔 4只 )。麻醉后 ,均切断左侧腓总神经 ,用 9 0尼龙单丝对端吻合神经外膜。各照射组在术后 1d开始照射家兔L5 ,6脊髓节段 ,照射激光输出功率为 2mW ,磁作用半导体激光照射采用在激光输出端安置强度为 5mT的恒磁场作用在激光上 ,每天照射 5min ,连续照射 7d。对照组不照射 ,均按期观察。结果 :术后 3周 ,各照射组看到细小而稀少的再生轴突 ,对照组直到术后 9周才看到 (P <0 .0 1) ,磁作用激光照射组优于激光照射组 (P <0 .0 5 ) ;各照射组的腓总神经潜伏速率和动作电位波幅均优于对照组 (P <0 .0 1) ,磁作用激光照射组优于激光照射组 (P <0 .0 5 )。展趾功能到术后 12周 ,磁作用激光照射组与侧健相同 ,激光照射组恢复到磁作用照射组 9周水平 ,对照组才恢复到磁作用半导体照射组近 6周的水平。结论 :低功率的磁半导体激光促进了脊髓运动神经细胞功能 ,加速了轴突再生。