In comparison: 1.064 μm-1.318 μm Nd-YAG continuous wave lasers. In vitro and in vivo experiments for endoscopic tumour therapy in the gastrointestinal tract

In in vitro and animal experiments the tissue effects of the 1.318m Nd-YAG laser were compared to those of the standard 1.064m Nd-YAG laser in order to evaluate the advantages of the new wavelength with a ten times higher absorption in water for gastroenterological tumour treatment. Under irradiation parameters related to clinical endoscopic practice, the laser of the wavelength 1.318m needs for both vaporization and coagulation significantly less energy than the 1.064m laser. Since vaporization at 1.318m is always accompanied by a higher coagulation effect compared to 1.064m the risk of late necrosis and resulting perforation appears to be increased.     

高压氧对人重症牙周炎牙龈血流量、血流速度和血浓度作用及机理研究

目的 :探讨高压氧 (HBO)对人重症牙周炎牙龈血流量 (GBF)、血流速度 (BCV)和血浓度 (BC)的作用及HBO治疗牙周炎的机理。方法 :选自口腔中心门诊的 3 0例重症牙周炎患者 ,随机分为二组 ,即治疗组和对照组 ,治疗组用HBO治疗 ,对照组用漱口液漱口。用激光多普勒血流仪测定二组治疗前后的GBF、BCV和BC。结果 :HBO能使牙周炎患者GBF增加 2 .1倍 ,BCV增加 6.7倍 ,BC降低为治疗前的 5 8.2 % ,与对照组比均有非常显著性差异 (P <0 .0 1)。结论 :HBO能使牙周炎患者GBF和BCV增加 ,BC减少 ,能改善牙龈微循环 ,对治疗牙周炎有积极意义     

半导体激光体外照射血管治疗仪的研制

为克服 He-Ne激光血管内照射疗法所具有的不足,我们采用830nm、500mW半导体激光器,研制了用于体外血管照射的激光治疗仪.设计了易于固定的激光输出头,并且采用单片机控制整机,提高了仪器的稳定性和可靠性.临床应用取得了令人满意的治疗效果.     

Spectral signature and heterodyne efficiency for different wavelengths in laser Doppler flowmetry

Laser Doppler perfusion monitoring and imaging technologies generate time traces and two-dimensional flow maps of the microcirculation. With the goal of reaching different tissue depths, these technologies are equipped with lassers operating at different wavelengths λ. The fact that the average scattering angle, at a single scattering event, between a photon and a red blood cell increases with λ is compensated for by a 1/λ effect in the scattering vector, rendering the average frequency shift virtually independent of the choice of wavelength. Monte Carlo simulations showed that the corresponding spectral signature of the Doppler signals for λ=632.8nm and 780nm were close to identical. The theoretical predictions were verified by calculating the centre-of-gravity (COG) frequency of the laser Doppler power spectral density for the two wavelengths from forearm and finger skin, representing a low and high perfusion area, respectively (forearm COG=123 against 121Hz, finger COG=220 against 212 Hz). When the wavelength changes from 632.8nm to 780nm, the heterodyne efficiency of the detector and, thereby, the inherent system amplifcation increase. For tissues with identical microvascular flow conditions, the output signal therfore tends to increase in magnitude when shifting to longer wavelengths.     

大鼠三叉神经脊束间质核内内脏神经初级传入终末与NOS阳性投射神经元的联系

目的　探查间质核 (INV)内内脏传入终末与向臂旁核 (PBN)投射的NOS阳性神经元之间的联系。　方法　逆行、跨神经节追踪以及免疫荧光组织化学方法 ,结合激光共聚焦扫描显微镜观察。　结果　PBN内注射四甲基罗丹明 (TMR)后 ,逆行标记细胞主要位于注射侧的INV ,大多属 2 0 μm以下的中、小型细胞。NOS阳性细胞与TMR逆行标记细胞分布区域重叠。NOS TMR双标记细胞分别占NOS阳性细胞总数的 5 4 8% (17 31)和TMR逆行标记细胞总数的 34% (17 4 9)。舌咽和迷走神经内注射生物素化葡聚糖胺 (BDA)跨神经节标记的内脏神经初级传入终末点状膨体贴近双标记细胞胞体 ,呈紧密接触状。　结论　可能存在经INV向PBN投射的内脏伤害性信息传导通路 ,作为神经递质和神经信息分子的NO可能参与其内脏伤害性信息的传递和调控     

Fibre optic confocal imaging (FOCI) of keratinocytes, blood vessels and nerves in hairless mouse skin in vivo

Fibre optic confocal imaging (FOCI) enabled subsurface fluorescence microscopy of the skin of hairless mice in vivo. Application of acridine orange enabled imaging of the layers of the epidermis. The corneocytes of the stratum corneum, the keratinocytes in the basal layers and redundant hair follicles were visualised at depths greater than 100 μm. Cellular and nuclear membranes of keratinocytes of the skin were visualised by the use of acridine orange and DIOC5(3). Imaging of the skin after injection of FITC-dextran revealed an extensive network of blood vessels with a size range up to 20 μm. Blood cells could be seen moving through dermal vessels and the blood circulation through the dermal vascular bed was video-taped. The fluorescent dye 4-di-2-ASP showed the presence of nerves fibres around the hair follicles and subsurface blood vessels. Comparison was made between images obtained in vivo using FOCI and in vitro scanning electron microscopy and conventional histology. FOCI offers the potential to study dynamic events in vivo, such as blood flow, skin growth, nerve regeneration and many pathological processes, in ways which have not previously been possible.     

激光扫描共聚焦显微镜在肿瘤研究中的应用

激光扫描共聚焦显微镜是近年来出现的一种新的分子细胞生物学分析仪器,已经广泛应用于生物医学研究的许多领域.简介其基本功能和特点.并从肿瘤组织细胞蛋白的定位和定量、肿瘤细胞亚细胞结构观察、肿瘤受体研究、肿瘤药物分布和肿瘤多耐药机制等角度.综述了近年来激光扫描共聚焦显微镜在肿瘤研究中应用的进展.     

低能量激光血管内照射治疗脑梗死的临床观察

目的:探讨采用低能量半导体激光血管内照射疗法(intravascular laser irradiation on blood,ILIB)治疗脑梗死的效果及机制.方法:随机选取80例脑梗死患者分为治疗组与对照组,两组各40例,两组患者接受同样的药物治疗,治疗组在上述治疗的基础上,于发病1 d～3 d内,加用半导体激光血管内照射治疗.采用国产半导体激光治疗仪,波长650nm,功率1.5mW～2.0mW.患者平卧,消毒后用静脉留置针穿刺上肢正中静脉或贵要静脉,成功后留置外套管,通过管脑导入激光剂,开启半导体激光治疗仪进行照射治疗.结果:治疗组有效率92.5%,与对照组差异有显著性意义(p＜0.01),治疗组患者临床症状和体征治疗后明显改善.结论:该疗法有调节脂质代谢,改善血液流变学性质,恢复神经传导功能等功效,进而提高脑梗死的治疗效果.     

Simulation of laser tomoscopy in a heterogeneous biological medium

A Monte Carlo model has been developed to study the propagation of an ultrashort light pulse through a heterogeneous thick biological specimen. A circular blood vessel is moved within a tissular slab to simulate biological specimen scanning using a picosecond laser source and a collimated ultrafast multichannel opticl shutter. Features of the transmitted light are computed for each position of the blood vessel. The computer program gives an account of the transmitted photons, the flight time which does not exceed straightforward crossing time plus time gate of known duration. A small blood vessel (radius R=2 mm) placed in a 40 mm thick slab is easily located when a time gate of 10 ps duration is employed. Such a time gate also allows the detection of a middle-sized vessel (R=4 mm) embedded in a thicker sample (80 mm). The contrast computed for the transmittance profile is greatly improved when a time gate is used. In addition, shifting of the blood vessel towards the unilluminated side of the sample decreases the contrast. We demonstrate that the time selection process may provide a substantial improvement to the laser tomoscopy technique when used for imaging biological media.