凑型准分子激光器的发展及其在医学中的应用

由于在绝缘材料和气体放电技术方面的进展,处于紫外波段的准分子激光器已经在工业、科学研究,特别是医学等领域成为主要应用工具.在本文中,我们将介绍新颖紧凑型准分子激光器在医学中的应用.此外,在文章中对紧凑型准分子激光器所采用的关键技术,诸如固态开关、电晕预电离和金属/陶瓷腔等技术进行了详细的讨论.     

准分子激光的医学应用

由于准分子激光对生物组织作用的独特机理─光化学分解作用,解决了许多临床治疗难题。近年来,难分子激光在激光医学中得到较广泛的应用。医用准分子激光种类主要有XeCl,308nm;ArF,193nm;KrF,248nm。本文介绍了准分子激光在医学中的几种典型应用。     

XeCl准分子激光消融几种生物组织的实验结果

本文报道了３０８ｎｍＸｅＣｌ准分子激光对人牙硬组织和猪肉软组织消融的实验研究结果,在国内首次开展了ＸｅＣｌ准分子激光牙科应用的基础研究,为准分子激光在牙科的临床应用提供了实验依据。     

准分子激光切削角膜的数学模型与切削技术研究

本文在分析国内外研究人眼角膜的数学模型的基础上,提出了能够用于进行近视、远视、散光等屈光手术的数学模型,并就准分子激光的切削原理和“飞点扫描”技术进行了研究,本文的研究成果直接用于准分子激光眼科治疗机,取得了满意的手术效果。     

PRK,LASIK技术在中国的应用

准分子激光屈光性角膜切削术（ＰＲＫ）和准分子激光原位角膜磨镶术（ＬＡＳＩＫ）是一种治疗眼球屈光不正的新技术,美国、德国、日本和中国（台湾）等国发展了多种准分子激光屈光治疗机以及相应的手术器械及软件,我国从１９９３年引进第一台ＰＲＫ机以来,已引进近百台机器,治疗屈光不正病例已超过十万。作者通过问卷调查和专家访问,对ＰＲＫ、ＬＡＳＩＫ技术在中国的应用状况进行了调查,在调查的基础上进行了分析,并对ＰＲＫ     

激光技术在医学领域中的新应用及我国的发展概况

1　在医学领域中的新应用1 960年美国科学家制造出世界第一台红宝石激光器 ,翌年立即用于临床治疗。激光技术在 40余年来取得了巨大成就。在医学领域内 ,激光技术已广泛应用于诊断、治疗及基础理论研究。由于激光器具有切割、凝固、气化、打孔、截骨等功能 ,目前已广泛应用于眼科、耳鼻喉科、皮肤科、普外科、神经外科和肿瘤科等。医用激光器作为手术治疗的器械 ,已充分显示了它无与伦比的优越性。近年在医学领域中的应用更是举世瞩目 ,拓展了临床应用 ,主要表现在以下一些范围中。1 .激光葡萄糖测定　美国 Spect Rt公司用激光无痛地在皮肤…     

激光辐照仪器及其在生物医学上的应用

激光辐照仪器及其在生物医学上的应用欧琳陈荣（福建师范大学物理系,福州３５０００７）激光辐照技术已经在细胞生物学、胚胎学、遗传学和医学中得到了广泛的应用。在激光医学中,应用不引起组织不可逆损伤的功率密度和能量密度激光进行照射治疗,称之为低强度照射疗法。...     

人眼波前像差表示、测量及矫正研究

目的:波前像差引导的准分子激光角膜消融是屈光手术的新方法,研究人眼波前像差的测量原理、方法、表示、人眼波前像差准分子激光矫正的原理,以此理论用于准分子激光人眼像差矫正系统。方法:采用理论研究、计算机模拟、实验室实验等手段。分析人眼像差的概念和产生的原因,用数学的Zern ike多项式来表示像差,理论上定量分析Zern ike多项式表示的波前像差与角膜切削深度的关系,研究准分子激光切削角膜的机理,研究准分子激光进行矫正人眼像差的原理框图。结果:通过计算机模拟和实验室实验,用准分子激光矫正低阶和高阶像差是可行的。结论:用波前像差来引导屈光手术,使人眼的视力能够达到20/10上,并能避免当前PRK、LASIK屈光手术前后像差增大而引起的对视觉质量的影响。     

激光技术在医学域领中的最新应用

1960年美国科学家制造出世界第一台红宝石激光器,翌年立即用于医疗。激光技术在40年来取得了巨大成就。在医学领域内,激光技术已广泛应用于诊断、治疗及基础理论研究。由于激光器具有切割、凝固、气化、打孔、截骨等功能,目前已广泛应用于眼科、耳鼻喉科、皮肤科、普外科、神经外科和肿瘤科等。医用激光器作为手术治疗的器械,已充分显示了它无与伦比的优越性。近年在医学领域中的应用更是举世瞩目,下面介绍几种激光技术最新应用情况。     

氮分子激光对雄性小家鼠生殖细胞染色体畸变率的影响

激光是六十年代出现的一门新兴技术。它具有能量高度集中、光色单一、方向性好等特点。激光在农作物育种上的应用已有不少报道,并证明有一定的诱变作用。在遗传效应的研究方面,也先后在各种农作物上观察到激光照射后能提高染色体畸变频率。在医学临床上,利用激光治疗各种疾病,并进一步开展了激光对生物和医学方面的基础理论研究。另     

Heat generation in laser irradiated tissue

Many medical applications involving lasers rely upon the generation of heat within the tissue for the desired therapeutic effect. Determination of the absorbed light energy in tissue is difficult in many cases. Although UV wavelengths of the excimer laser and 10.6 microns wavelength of the CO2 laser are absorbed within the first 20 microns of soft tissue, visible and near infrared wavelengths are scattered as well as absorbed. Typically, multiple scattering is a significant factor in the distribution of light in tissue and the resulting heat source term. An improved model is presented for estimating heat generation due to the absorption of a collimated (axisymmetric) laser beam and scattered light at each point r and z in tissue. Heat generated within tissue is a function of the laser power, the shape and size of the incident beam and the optical properties of the tissue at the irradiation wavelength. Key to the calculation of heat source strength is accurate estimation of the light distribution. Methods for experimentally determining the optical parameters of tissue are discussed in the context of the improved model.     

生物芯片、生物传感器和生物信息学

近年来,在生物技术和医学研究领域涌现出了许多新技术平台,其中就包括生物芯片技术和生物传感器技术。生物芯片和生物传感器的构建都必须以生物信息学为基础,而两种技术平台应用所得出的数据和结果又反过来大大丰富和充实了生物信息学本身。本分析概述了生物芯片和生物传感器两种技术平台以及生物信息学,对三之间的相互关系进行了讨论。     

Laser nanosurgery in cell biology

Since their first use in the early 60's, pulsed lasers have become increasingly popular for their ability to ablate biological tissue. Short laser pulses allow high precision surgery for biological and medical applications with minimal invasiveness. Performing highly targeted manipulation and ablation allows experiments impossible so far in development biology, cellular biology or even assisted reproductive technologies and laser surgery has been increasingly used over the last five years to answer key questions in Biology. Recently, picosecond UV and femtosecond IR laser pulses have been used to cleave microtubules and to severe actin stress fibers in vivo with a spatial precision in the submicrometer range to study their dynamics without affecting cell viability. We review recent findings on the underlying principles of pulsed laser nanosurgery mechanisms showing how the use of ultra short laser pulses increases precision and non-invasiveness of laser surgery. We show how the understanding of the surgical process allows one to distinguish between single cell ablation in living organisms or intracellular nanosurgery in living cells and we review recent applications to the study of forces and the quantification of cytoskeleton dynamics.     

Modeling of self-sustained discharge-pumped,Ne-buffered XeCl laser kinetics

The aim of this work is to highlight some quantities characterizing the Ne/Xe/HCl gas mixture plasma at high pressure and under uniform preionization conditions. This mixture is used as excitation medium for XeCl excimer lasers. A comprehensive model of discharge kinetics is presented. The model combines the physical processes in the discharge with the chemistry of formation and destruction of the excimer molecule. It is based on an extensive reaction scheme including the major electronic and ionic processes. The importance of excited atomic and molecular states is demonstrated. A parametric study is presented.     

Advances in quantitative proteomics

Large-scale protein quantification has become a major proteomics application in many areas of biological and medical research. During the past years, different techniques have been developed, including gel-based such as differential in-gel electrophoresis (DIGE) and liquid chromatography-based such as isotope labeling and label-free quantification. These quantitative proteomics tools hold significant promise for biomarker discovery, diagnostic and therapeutic applications. They are also important for research in functional genomics and systems biology towards basic understanding of molecular networks and pathway interactions. In this review, we summarize current technologies in quantitative proteomics and discuss recent applications of the technologies.     

生物组织激光消融阈值的光谱特性

在一个宽光谱范围内研究不同激光作用下生物组织的消融,对理解激光与组织间相互作用及开发激光在外科的新应用有着极其重要的意义。其中消融阈值及其与激光波长的函数依赖关系是激光外科研究的重点。阐述了消融阈值的物理描述,并对消融阈值的波长依赖关系进行了初步探讨。     

Cytoplasmic molecular delivery with shock waves: importance of impulse

Cell permeabilization using shock waves may be a way of introducing macromolecules and small polar molecules into the cytoplasm, and may have applications in gene therapy and anticancer drug delivery. The pressure profile of a shock wave indicates its energy content, and shock-wave propagation in tissue is associated with cellular displacement, leading to the development of cell deformation. In the present study, three different shock-wave sources were investigated; argon fluoride excimer laser, ruby laser, and shock tube. The duration of the pressure pulse of the shock tube was 100 times longer than the lasers. The uptake of two fluorophores, calcein (molecular weight: 622) and fluorescein isothiocyanate-dextran (molecular weight: 71,600), into HL-60 human promyelocytic leukemia cells was investigated. The intracellular fluorescence was measured by a spectrofluorometer, and the cells were examined by confocal fluorescence microscopy. A single shock wave generated by the shock tube delivered both fluorophores into approximately 50% of the cells (p < 0.01), whereas shock waves from the lasers did not. The cell survival fraction was >0.95. Confocal microscopy showed that, in the case of calcein, there was a uniform fluorescence throughout the cell, whereas, in the case of FITC-dextran, the fluorescence was sometimes in the nucleus and at other times not. We conclude that the impulse of the shock wave (i.e., the pressure integrated over time), rather than the peak pressure, was a dominant factor for causing fluorophore uptake into living cells, and that shock waves might have changed the permeability of the nuclear membrane and transferred molecules directly into the nucleus.     

Changes in gene expression by 193- and 248-nm excimer laser radiation in cultured human fibroblasts.

Tissue ablation by ultraviolet excimer lasers results in exposure of viable cells to subablative doses of radiation. To understand the potential biological consequences better, we have studied changes in gene expression in cultured human skin fibroblasts exposed to either 193- or 248-nm laser light. Northern blot analyses revealed that both treatments up-regulate a common set of genes, including interstitial collagenase, tissue inhibitor of metalloprotease, metallothionein, and the proto-oncogene c-fos. Dose-response and kinetic studies of collagenase induction by 193-nm radiation showed a maximal effect with 60 J/m2 and at approximately 24 h. The induction was still persistent 96 h later. In addition to the commonly affected genes, known to be activated also by conventional UV light (254 nm) and tumor-promoting phorbol esters, other genes were found to be selectively induced by the 193-nm radiation. The heat-shock hsp70 mRNA, undetectable in controls and in cultures irradiated at 248 nm, was transiently induced 8 h after exposure to 193-nm radiation. Furthermore, a selective up-regulation of collagen type I expression was observed. The results indicate that the 193- and 248-nm radiations by excimer lasers elicit specific and different cellular responses, in addition to an overlapping pathway of gene activation common also to UV radiation by germicidal lamps. The laser-induced genes could serve as molecular markers in evaluating cell injury in situ.