Histochemical study of transmyocardial laser channels in dogs

目的　了解激光心肌血运重建术时激光对心肌的损伤。方法　在狗心肌上用CO2 激光打孔。术后即刻、两周时于打孔处取材 ,用硝基蓝四唑法作琥珀酸脱氢酶、乳酸脱氢酶组织化学染色。结果　术后即刻 ,孔道及其周围心肌分为五个区。中央为孔道即组织汽化区 ,向外依次为碳化区、酶消失区、酶减少区、酶浓缩区。两周后孔道区被肉芽组织取代 ,周围心肌细胞酶活性正常。结论　激光心肌血运重建术术后即刻 ,孔道周围心肌细胞酶活性由内向外依次呈消失、减少、浓缩改变。术后两周可逆性损伤的心肌细胞酶活性恢复。     

Therapeutic effects of undercorrection by LASIK following RK and PRK for correction of high myopia

WiththeextensivedeveIopmentofradialkerato--tomy(RK)and(photorefractivekeratectomy(PRK),thepostopcrativeundercorrectioncausedbyvarioustypesofcauses,especiallyinthecasesofSD(sphericaldiopter)>--6.0D,hasbecomeaknottyprobleminclinicalpractice.TreatmentofRKorPRKagainwouldprobablyencounterinundercorrec-tion.Moreover,theoperationwascomplicatedandcomplicationsoccurfrequently,especiallyforthosepatientshavingepisodeofhormone--inducedglaucomapreviously.Inourcenter,wecorrectedwlthLASlKandachievedsa…     

OBSCAN-Ⅱ眼前节诊断系统检测正常成人眼角膜最薄点

用OBSCAN-Ⅱ眼前节诊断系统对50例（100眼）正常成人角膜进行全角膜厚度检测,重点观测角膜最薄点的厚度位置。结果表明,角膜最薄点厚度的平均值为(554.33±34.46)μm,与角膜中心点厚度相关系数为0.976,但最大相差值可达23μm,角膜最薄点位置在角膜中心点(0.58±0.26)mm半径范围内,以颞下方为多。结果提示OBSCAN-Ⅱ眼前节诊断系统对角膜最薄点的检测更为精确。     

半导体激光穴位照射的镇痛作用及其机制初探

目的　探讨半导体激光穴位照射镇痛效应及其镇痛的机制。方法　大鼠随机分成照射组、模拟照射组和纳洛酮预处理组。采用半导体激光照射大鼠“足三里”穴位 ,用电刺激鼠尾 -嘶叫法测定激光照射前后的痛阈。结果　照射后大鼠的痛阈明显提高 ,这种镇痛作用可被纳洛酮预处理所翻转。结论　半导体激光穴位照射产生镇痛效应机制可能与激光照射促进内源性阿片物质释放有关。     

声带息肉和声带小结的治疗与发声效率

[目的 ]研究声带息肉和声带小结的治疗方法 .[方法 ]对 30例声带息肉患者和 2 0例声带小结患者进行了喉显微外科手术或激光喉显微外科手术 ,并在术前及术后分别测量了其发声效率 .[结果 ]在声带息肉组中 ,手术前后发声效率有显著性差异 ;在声带小结组中 ,手术前后发声效率无显著性差异 .[结论 ]对于声带息肉患者喉显微外科手术 (包括激光 )是较好的治疗方法 ,对于声带小结患者 ,当各种保守治疗无效时 ,考虑选择喉显微外科手术     

氩激光治疗视网膜静脉阻塞新生血管的临床研究

为探讨、分析氩激光治疗视网膜阻塞新生血管的疗效。氩激光治疗视网膜静脉塞新生血管５５例,中央静脉塞行全视网膜光凝。分支静脉阻塞区域播散性光凝,光斑２００－５００μｍ,时间０．１－０．２ｓ,能量０．１２－０．４ｗ,Ⅱ级光斑,蓝绿色光波,黄斑格栅光凝光斑１００μｍ,时间０．１ｓ,能量视病情而定,以Ⅰ级反应为度,绿色光波。结果：５５例中４４例有效,新生儿血管消嫁总有效率８０％,无效１１例（其中视盘有新生血     

Confocal Laser Scanning Microscopic Visualization of the Transport of Dextrans After Nasal Administration to Rats: Effects of Absorption Enhancers

Purpose. To visualize the transport pathway(s) of high molecular weight model compounds across rat nasal epithelium in vivousing confocal laser scanning microscopy. Furthermore, the influence of nasal absorption enhancers (randomly methylated -cyclodextrin and sodium taurodihydrofusidate) on this transport was studied. Methods. Fluorescein isothiocyanate (FITC)-labelled dextrans with a molecular weight of 3,000 or 10,000 Da were administered intranasally to rats. Fifteen minutes after administration the tissue was fixed with Bouin. The nasal septum was surgically removed and stained with Evans Blue protein stain or DiIC18(5) lipid stain prior to visualization with the confocal laser scanning microscope. Results. Transport of FITC-dextran 3,000 across nasal epithelium occurred via the paracellular pathway. Endocytosis of FITC-dextran 3,000 was also shown. In the presence of randomly methylated -cyclodextrin 2% (w/v) similar transport pathways for FITC-dextran 3,000 were observed. With sodium taurodihydrofusidate 1% (w/v) the transport route was also paracellular with endocytosis, but cells were swollen and mucus was extruded into the nasal cavity. For FITC-dextran 10,000 hardly any transport was observed without enhancer, or after co-administration with randomly methylated -cyclodextrin 2% (w/v). Co-administration with sodium taurodihydrofusidate 1% (w/v) resulted in paracellular transport of FITC-dextran 10,000, but morphological changes, i.e. swelling of cells and mucus extrusion, were observed. Conclusions. Confocal laser scanning microscopy is a suitable approach to visualize the transport pathways of high molecular weight hydrophilic compounds across nasal epithelium, and to study the effects of absorption enhancers on drug transport and cell morphology.     

Hard tissue laser ablation mechanisms

The aim of this work is the experimental and theoretical investigation of the influence of variable laser parameters (wavelength, fluence, pulse repetition rate) and of the optical and thermophysical properties of bone tissue (absorption coefficient, tissue inhomogeneity) as well as of the sample thickness on ablation thresholds and ablation rate. Ablation and perforation experiments were conducted using a semiconductively pre-ionized transverse excitation atmospheric pressure (TEA) carbon dioxide (CO₂) laser (10.6m and a sliding discharge TEA [hydrogen fluoride (HF)] laser (2.9m). The experimental data are discussed with respect to the following ablation mechanisms: thermal melting and vaporization process, pressure oscillation of gases released by the thermal decomposition of collagen and/or apatite, stresses due to the expansion of superheated water.     

The effect of the illumination time when treating port-wine stains

This paper reports the electron microscopy results obtained from two patients who were treated with 5 W of yellow (578 nm) light from a copper vapour laser with an illumination time of 3.6 ms and a 0.3 mm spot diameter. The endpoint of treatment was transient blanching. Following treatment, erythema was observed. There was minimal damage to the epidermis and non-vascular tissue such as the nerve fibres. There was severe damage to the endothelial cells of the ectatic vessels. Twenty-four hours after treatment, platelet activation and collagen were present, indicating that these vessels were no longer viable. Theoretical calculations are used to determine the flow of heat within and away from a 50m diameter vessel. From this, heating of the entire vessel is shown to occur with illumination times of 4 ms, with minimal heating of the non-vascular tissue. Shorter illuminations do not heat the entire vessel, while the use of longer illumination times will cause excessive damage to the surrounding non-vascular tissue. Illumination times close to 4 ms must be regarded as optimal.     

Holmium: YAG laser surgery in obliterated cochleas: an experimental study in human cadaver temporal bones

A pulsed holmium: YAG laser ( = 2120 nm) was used to reopen the basal turn of artificially obliterated human cochleas in freshly dissected cadavers. This allowed intracochlear insertion of the stimulation electrode of a cochlear implant under simulated surgical conditions. Laser energy was transmitted through a 400-m nylon fiber via the opened facial recess directly to the round window niche. At an energy level of 500 mJ per 2.5 s pulse, a repetition rate of 2 Hz, and an exposure time of 20–30 s, the photo-ablative mechanism of laser-bone interaction led to a 8–10 mm recanalization of the basal turn of the cochlea without damaging surrounding structures. The artificial bony occlusion and the recanalized basal turn of the cochlea were visualized by means of computed tomography and studied under light microscopy, using a histologic thin-section technique.Presented at the XVth World Congress of Otorhinolaryngology, Istanbul, Turkey, 23 June 1993