Er,Cr:YSGG激光照射对牙根尖封闭效果影响的实验研究

目的:深入探讨在根尖倒充填术中Er,Cr:YSGG激光照射对牙根尖的封闭效果,为此激光在口腔临床上的应用与推广提供重要的理论与实验依据。方法:将56颗新拔除的单根牙随机分成7组,每组8颗牙。去除牙冠,常规进行根管预备、根管充填。将倒充填的牙根尖进行预备,然后银汞合金倒充填。预备方法:1手机切除根尖后,制备成烧瓶状洞形;2手机处理方法同1,然后Er,Cr:YSGG激光于不同能量(1W、2W)及不同方式(喷水或无水)下对洞内壁进行照射。结合微渗漏检测与扫描电镜观察对Er,Cr:YSGG激光照射后的牙根尖封闭效果进行评估。结果:Er,Cr:YSGG激光可有效去除根切面上的玷污层及碎屑;与手机加银汞倒充填组相比,激光照射后的根尖染料微渗漏深度有所减少;但只有1WEr,Cr:YSGG激光于无水条件下照射时,根尖染料微渗漏深度显著减少(P<0.05)。结论:Er,Cr:YSGG激光应用于根尖倒充填术中可减少微渗漏的发生;促进根尖封闭;在特定的能量参数下可获得优于常规银汞倒充填术的治疗效果。因此我们推荐临床上将Er,Cr:YSGG激光照射与常规银汞倒充填术结合使用,这将有助于提高根尖倒充填术治疗的成功率。     

Effect of helium-neon laser radiation on the radiosensitivity of Escherichia coli K-12 cells

A study was made of the combined effect of laser radiation (helium-neon laser, lambda = 633 nm) and X-rays on bacteria of different genotypes. The sensitivity of cells to X-rays was decreased by pre- and post-irradiation with laser. In the latter case, the radio-modifying effect of laser was more pronounced.     

低强度激光鼻腔照射对血脂异常作用的研究

目的：观察低强度激光（650nm／5mw）鼻腔照射疗法对血脂异常的作用。方法：30例原发性血脂异常患者随机分为两组,分别接受药物（舒降之）治疗和低强度激光鼻腔照射疗法,测定治疗前后的血脂水平。结果：在调整饮食的基础上,低强度激光经鼻腔照射使病人的血清总胆固醇水平降低了5．8％（P=0．031）,甘油三酯降低了8．8％;低强度激光鼻腔照射在有效调整血脂的同时,使谷丙转氨酶（J唧）水平下降了23．1％（P=0．022）,对肝功能具有保护作用。结论：与舒降之相比,低强度激光鼻腔照射疗法的调脂效果虽然相对较弱,但基于安全性的考虑,在饮食控制无效或肝功能异常的病人中使用低强度激光鼻腔照射仍然具有一定的应用价值。     

Er,Cr:YSGG激光照射对根管封闭效果影响的实验研究

探讨常规根管预备后使用不同能量参数Er,C r:YSGG激光进行根管内照射对根管封闭效果的影响,为此激光在根管治疗领域的临床应用提供重要的实验依据。选择新拔除的单根管牙80颗,分成4组,每组20颗牙。常规根管预备后,分别使用1 W、2 W、3 W Er,C r:YSGG激光于有水条件下进行根管内照射,另选一组不做任何处理,作为阴性对照。扫描电子显微镜下观察根管内壁形态学改变后,常规根管充填,检测根管微渗漏情况。采用单因素方差分析及q检验进行统计学处理。结果可见:(1)形态学观察:与对照组相比,激光照射均可有效去除根管内壁的玷污层及碎屑;牙本质小管口清晰可见;未见熔融及炭化等热损伤改变;其中3 W激光处理后根管内壁形态最为理想。(2)微渗漏检测:与对照组相比,各激光组根管微渗漏深度均显著减少(P<0.05);但各激光组间比较无显著性差异(P>0.05)。综上,使用Er,C r:YSGG激光进行根管内照射可达到较为理想的根管清洁目的,显著改善根管充填后的封闭效果,因此有望在临床上应用提高根管治疗的成功率。     

基于LED作为照射光源的血疗法可行性研究

通过对LED在生物医学领域的应用分析发现,LED光存在与激光相类似的生物刺激效应。目前弱激光血疗已由血管内照射发展到体表照射、黏膜照射。这为LED光照射体表、黏膜实现血疗提供了良好的预期。为了证明LED光可以代替激光作为净血治疗仪的光源,本实验设计了激光与LED光对自由基损伤模型红细胞变形性作用的对比实验,结果表明,两种光照方法均对红细胞变形性有改善作用。LED相比激光安全性更好、成本更加低廉,特别适合往家用小型化方向发展。     

Effect of the distance between adherent mesenchymal stem cell and the focus of irradiation of femtosecond laser on cell replication capacity

The effect of femtosecond laser irradiation on adherent mesenchymal stem cell was investigated with the aim to develop a novel noninvasive cell purification system. A single mesenchymal stem cell was irradiated with a femtosecond laser on the center of the cell using several energy values and the cell lost its replication capacity with one time irradiation with an energy of 2.0 μJ. Besides at a neighbor point in the major axis, when irradiated in the minor axis at a distance shorter than 10 μm, the cell stopped its replication capacity. The accumulation effect of cell damage caused by multiple laser shots at a neighbor point in the minor axis was correlated with the critical distance at which the cell lost its replication capacity. Finally, a novel equation of laser cell damage as a function of laser pulse energy and laser shot number is proposed.     

半导体激光辐照DNA的光谱分析

本文通过半导体激光等辐照源对ＤＮＡ辐照,研究激光、紫外、普通红光对ＤＮＡ吸收光谱的影响。发现激光（６６０ｎｍ）与紫外（峰值波长２５４ｎｍ）均能使ＤＮＡ吸收峰值改变,表明它们均能被ＤＮＡ吸收,与ＤＮＡ发生作用,从而使ＤＮＡ构型发生变化,但激光、紫外与ＤＮＡ作用机理是不同的。而普通红光（峰值波长６６０ｎｍ）对ＤＮＡ光谱无甚影响,这说明了激光与ＤＮＡ作用的非线性共振吸收存在。并发现在激光辐照ＤＮＡ时,激光剂量不同以及ＤＮＡ溶液浓度不同,对ＤＮＡ光谱的影响也不同。这些结果对激光育种和激光生物学实验有一定参考价值。     

A study of the effect of low-intensity laser radiation of the blue, green, and red spectral regions on the healing of experimental skin wounds in rats

The effect of low-intensity laser radiation of the blue (441.2 nm), green (532 nm), and red (632.8 nm) spectral regions on the healing of experimental skin wounds in rats has been studied. The effect of the traditionally applied laser radiation in the red region has been compared with the effect of laser radiation in the other spectral regions, assuming that, upon irradiation of wounds by lasers emitting in the blue and green regions, a similar effect can be achieved at lower doses. The following parameters characterizing the healing of experimental wounds were used: the functional activity of phagocytes of wound exudates, which was determined by luminol-dependent chemiluminescence, and their number; the antioxidant activity of wound exudates; and the rate of healing, which was determined as a change in the wound area. It was shown that irradiation with laser accelerated the healing of wounds in all cases. The exposure to laser radiations in the red (1.5 J/cm), blue, and green (0.75 J/cm2) spectral regions shortened the time of wound healing from 22 to 17 and 19 days, respectively. The functional activity of leukocytes after the exposure increased on day 5 after the infliction of the wound, whereas in the control it decreased. The superoxide dismutase activity increased in all experimental groups by day 5 after the operation. A maximum increase in the superoxide dismutase activity occurred after the exposure to laser radiation in the red region at a dose of 1.5 J/cm and in the blue and green spectral regions at a dose of 0.75 J/cm2.     

激光辐照洋葱L1代的生理效应研究

采用ＣＯ２和Ｈｅ－Ｎｅ两种激光的三种剂量,分别辐照两个洋葱品种的湿种子,采用生理生化的方法,从过氧化氢酶、叶绿素、总糖总量等三个方面考查研究洋葱Ｌ１各处理的生物学效应。结果表明：Ｈｅ－Ｎｅ激光辐照洋葱Ｌ１代的过氧化氢酶、叶绿素、总糖含量的变异大于ＣＯ２激光辐照,可作为激光诱导变洋葱育种参考。     

弱激光对大鼠胃运动的调节及其作用途径分析

采用成年Ｗｉｓｔａｒ雄性大鼠,应用Ｒａｙｂｏｕｌｄ法测定了弱激光照射足三里穴对大鼠胃运动的调节作用,实验结果为：（１）弱激光照射足三里穴对大鼠胃内压及胃收缩频率均有明显升高作用;（２）腹腔预先注射酚托拉明,部分抑制了弱激光效应;（３）腹腔预先注射心得安,显著地抑制了弱激光的升压及升频作用,并使胃内压及胃收缩频率低于单纯心得安的效应值;（４）腹腔预选注射纳洛酮,部分抑制了弱激光的效应;（５）腹腔预先     

激光诱变洋葱生理效应研究Ⅱ

采用CO2和He-Ne两种激光的三种剂量,分别辐照两个洋葱品种的湿种子,采用生理生化的方法,从净同化率,净光合速率,呼吸速率,蛋白质含量等四个方面研究洋葱各处理的生物学效应。结果表明：He-Ne激光辐照洋葱的净同化率,净光合速率,呼吸速率,蛋白质含量的变异大于CO2激光辐照,采用He-Ne激光辐照洋葱容易从其变异后代中选择出高产,优质的优良变异株,进而育成符合育种目标的优良新品种。     

Regulatory role of low-intensity laser radiation on the status of the antioxidant system

On the base of modern literary data it is shown that low level laser red radiation can render the manifested effect on the activity of main antioxidant enzymes. It is determined that the main enzymes of antioxidant system--superoxide dismutase, catalase, ceruloplasmine--absorb in the red part of spectrum and are capable to be reactive under some regimes of red low level laser irradiation. It is one of the main possible mechanisms of biological efficiency of low level red laser radiation of the red part of spectrum.     

Modification of the damaging effect of alpha-particles on Escherichia coli K-12 by low-intensity laser irradiation

A study was made of the combined effect of laser (helium-neon laser, lambda = 633 nm) and alpha-radiation on survival of Escherichia coli K-12 cells of different genotypes. Pre- and post-irradiation exposures to laser-radiation diminished the damaging effect of alpha-particles. In the latter case, modification of survival was more pronounced.     

超连续谱激光可见谱段致人眼眩目效应研究

本文采用超连续谱激光光源滤除其红外部分仅输出可见谱段部分,在不超过国家安全标准允许的最大辐照量条件下,以正入射方式照射人眼后,记录并分析在明、暗适应条件下中心极限视力恢复时间、中心近极限视力恢复时间和视觉后像持续时间,明确超连续谱激光可见谱段对人眼的眩目效果。明适应下激光照射0.1 s导致人眼中心极限视力恢复时间为31~119 s,中心近极限视力恢复时间为19~76 s;暗适应下激光照射0.1 s导致人眼中心极限视力恢复时间为26~223 s,中心近极限视力恢复时间为13~123 s;明、暗适应下导致人眼眩目效应的最小功率密度值分别为0.055 mW/cm^2和0.005 mW/cm^2。结果表明,超连续谱激光可见谱段对人眼有良好的眩目效果,可导致数十秒至数百秒的中心视力下降,随着照射功率密度增高,眩目效应增强,显示出较好的量效关系,且相同功率密度时暗适应下人眼的眩目效果优于明适应。该研究探究了明、暗适应条件下超连续谱激光对人眼眩目效应,明确了超连续谱激光与人眼眩目的量效关系。     

Critical evaluation of indications for the holmium:YAG laser and the neodymium:YAG laser in orthopedic surgery based on an in vitro study]

This is an in vitro study of the biophysical effects of holmium:YAG and neodymium-YAG lasers that was prompted by the poor clinical results obtained with lumbar percutaneous laser discus decompression (PLDD). In the absence of adequate cooling, ablation of tissue with the holmium:YAG laser causes thermal damage to the surrounding tissues. Utilizing the immediate colour-independent laser coupling effect, the holmium:YAG laser removes soft and hard tissue immediately. The low tissue penetrating power (max. 0.32 mm), together with the use of irrigation, avoids thermal problems, and this laser type with its high pulse energy and frequency is to be recommended for arthroscopic surgery. In contrast, the effects of the neodymium:YAG laser are highly dependent on tissue colour. Using this laser on light-coloured tissue only diffuse warming but no ablation of soft tissue was often seen. The depth of tissue penetration seen in our study was 0.58 mm, but is greatly dependent on the duration of application, and is much larger with long application times. In conclusion, we believe that the neodymium:YAG laser is more suitable for percutaneous intradiscal procedures than the holmium:YAG laser. For arthroscopic surgery, the holmium:YAG laser will be the better choice. The effect of each type of laser depends not only on its physical properties, but also on tissue properties (light or dark-coloured, thermal conductivity) and duration of application.     

曲酸产生菌激光诱变效应的研究

采用经紫外线(UV)、^60Co、亚硝基胍(NTG)复合诱变得到的黄曲霉曲酸产生菌(UCN7—12),进行激光诱变处理。研究证实在经过UV、^60Co、NTG诱变处理后,黄曲霉突变株用He—Ne激光与YAG激光进行诱变处理仍能提高产酸率,其中He—Ne激光辐照处理20min,正变率为12．1％,产量提高约13％。YAG激光辐照处理300sec,正变率16．7％,产量提高18．3％。说明上述两种激光对黄曲霉曲酸产生菌有一定的诱变效应。     

The action of helium-neon laser radiation on the growth of Mycobacterium tuberculosis

The growth properties of M. tuberculosis subjected to the action of helium-neon laser radiation was studied. Laser radiation was shown to change the quantitative and qualitative composition of mycobacterial population. Disturbances in the viability of mycobacteria appear as a consequence of changes in the morphological structure of mycobacterial cells. The maximum effect of helium-neon laser radiation was achieved after the irradiation of M. tuberculosis culture on days 2-3 after inoculation. These results made it possible to suggest that the effect of helium-neon laser radiation was most pronounced in cells at the stage of mitosis (the logarithmic stage of growth) with the highest degree of metabolism.     

Further studies on the effect of low-dose laser irradiation on cultured retinal pigment cells of the chick

The effect of low-intensity laser irradiation on pigment cells cultured by chorioallantoic method was studied. Laser irradiation influenced the cell shapes and sizes of the pigment cells. Metabolically, this treatment increased thymidine uptake and incorporation but reduced those of leucine. The phagocytic activity as measured by latex particles uptake was not affected. It was concluded that the biological effect of laser irradiation on cell cultures depends on the dose applied, the individual tissue and other factors.     

Mechanism of the antiarrhythmic effect of laser irradiation]

Acute experiments were performed to study the role of afferent impulses from the heart receptors which pass by different vagal fibers during intraatrial laser irradiation. Double laser irradiation of the right atrium seemed more effective than a single one as to decreasing ventricular arrhythmias during cardiac ischemia. It is shown that the antiarrhythmic effect of intraatrial laser irradiation may be due to the change of the afferent information passing by myelinated vagal fibers.     

低功率He-Ne激光照射下细胞内活性氧自由基的产生和游离Ca^2＋浓度的研究

在临床应用中,低功率He-Ne激光(632.8 nm)能促进骨骼肌修复,加速创伤愈合,降低牙齿的超敏感性,减缓疼痛等.大量研究表明:低功率He-Ne激光能调节细胞的众多行为,如细胞增殖、分泌、迁移、粘附、蛋白质合成和基因表达等.但低功率He-Ne激光调节细胞行为的分子机制并未阐明,考察低功率He-Ne激光照射后细胞内活性氧自由基的产生水平和游离ca2 浓度是否会发生变化,通过激光扫描共聚焦显微镜,分别利用H:DCFDA和Fluo-3/AM这两种荧光探针,检测到经He-Ne激光照射后,肺腺癌细胞内活性氧自由基的水平上调以及游离Ca2 浓度增加.该研究为低功率He-Ne激光的生物光刺激效应提供了可能的分子机理.