激光辐照鱼类胚胎导致畸变

红激光(He—Ne,632.8nm)辐照金鱼(Carassius aurafus)受精卵和怀胎孔雀鱼(Poecilia reticulata),导致两种鱼胚胎畸变。金鱼胚胎在某一发自阶段的畸变率随辐照剂量的增加而提高;在同一剂量辐照下,不同发育期的胚胎畸变率各异,胚胎发育初期畸变率最高,此后随胚胎发育过程畸变率下降。经He—Ne激光辐照的孔雀亲鱼也能生产畸形仔鱼。在实验中还比较了红激光(632.8nm)和紫激光(N_2337.1nm)辐照金龟卵致变效果。     

紫外激光消融主动脉斑块和感生荧光光谱观测

利用XeCI准分子激光辐照主动脉血管正常组织和斑块组织,观察到组织被激光消融。消融所产生的凹坑与辐射时间呈对数直线关系。308nm激光感生的血管壁荧光光谱在可见波段出现二个荧光极大值,用二极值的相对强度之比可以判断正常或斑块组织。     

紫外激光消融主动脉斑块和感生荧光光谱观测

利用XeCI准分子激光辐照主动脉血管正常组织和斑块组织,观察到组织被激光消融。消融所产生的凹坑与辐射时间呈对数直线关系。308nm激光感生的血管壁荧光光谱在可见波段出现二个荧光极大值,用二极值的相对强度之比可以判断正常或斑块组织。     

XeCl准分子激光辐照对溶菌酶结构的影响

利用荧光光谱、SDS-PAGE和NMR方法,考察308 nm XeCl准分子激光辐照对溶菌酶结构与活性的影响。使用能量密度为0.3 mJ/mm2的激光辐照溶菌酶,脉冲数分别为25、50、100、200、600、1200、1800、3600和7200。结果表明,用低强度激光辐照(低于200个脉冲)时,溶菌酶的活性出现增高趋势。随着激光辐照脉冲数的进一步增大,溶菌酶的活性又开始逐步降低。激光辐照处理后,溶菌酶的荧光强度发生了与生物活性相对应的先增高再降低现象,说明溶菌酶的高级结构发生了显著变化。SDS-PAGE结果显示,经激光辐照后,溶菌酶出现了分子间的聚合。分析溶菌酶的1H-NMR谱发现,辐照后,溶菌酶色氨酸(Trp)111、Trp63和Trp62的化学位移发生了变化,此结果进一步说明,激光辐照使溶菌酶的高级结构发生了变化。该实验可为激光辐照诱导蛋白质去折叠的研究提供参考。     

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。     

多管藻R—藻红蛋白的激光光敏作用对体外培养的肿瘤细胞生存…

用１００μｇ／ｍｌ藻红蛋白联合激光处理８１１３人口腔上皮癌细胞,ＭＴＴ比色法测定癌细胞存活率。实验表明,先用藻红蛋白处理再经波长为４８８ｎｍ,２５．６Ｊ／ｃｍ＾２氩离子激光辐照,细胞存活率为２５％;而单用藻红蛋白,单用激光组分别为４３％和１０７％。结果证明,藻红蛋白的光敏作用对体外培养的肿瘤细胞具有较强的杀伤作用。     

多管藻R-藻红蛋白的激光光敏作用对体外培养的肿瘤细胞生存率的影响

用１００μｇ／ｍｌ藻红蛋白联合激光处理８１１３人口腔上皮癌细胞,ＭＴＴ比色法测定癌细胞存活率。实验表明,先用藻红蛋白处理再经波长为４８８ｎｍ,２５．６Ｊ／ｃｍ２氩离子激光辐照,细胞存活率为２５％;而单用藻红蛋白,单用激光组分别为４３％和１０７％。结果证明,藻红蛋白的光敏作用对体外培养的肿瘤细胞具有较强的杀伤作用。     

半导体激光辐照对花生种子活力的影响

采用３５０ｎｗ,８１０ｎｍ近红外光导体激光辐照花生干种子,经激光辐照后,种子胚根生长速度加快,胚根长度增加,侧根数目增加,种子出苗率提高。幼苗苗鲜重与根鲜重指标均高于对照组。实验证明,适当剂量的近红外半导体激光辐照可提高花生种子活力,促进幼苗生长。     

激光辐照微藻的显微图像观察及荧光定量分析

利用激光共聚焦扫描显微镜观察激光辐照前后微藻细胞叶绿体自体荧光图像,并对荧光变化进行定量分析。用Nd:YAP激光辐照扁藻、金藻及三角褐指藻。实验结果表明:Nd:YAP激光辐照后,藻细胞荧光光谱峰位不变,但荧光峰值发生较大变化,在激光促长剂量辐照下,几种微藻细胞的荧光强度均比对照组强。激光辐照微藻产生的生理刺激效应可以反映在细胞的荧光特性与强度变化上。激光共聚焦扫描显微镜可以作为微藻激光生物效应研究的一种有效方法。     

The optical effect of a semiconductor laser on protecting wheat from UV-B radiation damage.

Lasers have been widely used in the field of biology along with the development of laser technology, but the mechanism of the bio-effect of lasers is not explicit. The objective of this paper was to test the optical effect of a laser on protecting wheat from UV-B damage. A patent instrument was employed to emit semiconductor laser (wavelength 650 nm) and incoherent red light, which was transformed from the semiconductor laser. The wavelength, power and lightfleck diameter of the incoherent red light are the same as those of the semiconductor laser. The semiconductor laser (wavelength 650 nm, power density 3.97 mW mm(-2)) and incoherent red light (wavelength 650 nm, power density 3.97 mW mm(-2)) directly irradiated the embryo of wheat seeds for 3 min respectively, and when the seedlings were 12-day-old they were irradiated by UV-B radiation (10.08 kJ m(-2)) for 12 h in the dark. Changes in the concentration of malondialdehyde (MDA), hydrogen peroxide (H(2)O(2)), glutathione (GSH), ascorbate (AsA), carotenoids (CAR), the production rate of superoxide radical (O(2)(-)), the activities of peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) and the growth parameters of seedlings (plant height, leaf area and fresh weight) were measured to test the optical effect of the laser. The results showed that the incoherent red light treatment could not enhance the activities of SOD, POD and CAT and the concentration of AsA and CAR. When the plant cells were irradiated by UV-B, the incoherent red light treatment could not eliminate active oxygen and prevent lipid peroxidation in wheat. The results also clearly demonstrate that the plant DNA was damaged by UV-B radiation and semiconductor laser irradiance had the capability to protect plants from UV-B-induced DNA damage, while the incoherent red light could not. This is the first investigation reporting the optical effect of a semiconductor laser on protecting wheat from UV-B radiation damage.     

Antimicrobial activity of argon fluoride (ArF) excimer laser on gram-negative bacteria

The objective of this study was to evaluate the antibacterial activity of argon fluoride (ArF) excimer laser radiation on clinically important strains of gram-negative bacteria. The antibacterial activity of ArF excimer laser radiation was evaluated on two Acinetobacter baumannii, one Enterobacter cloacae, three Escherichia coli, two Helicobacter pylori, one Klebsiella pneumoniae and two Pseudomonas aeruginosa strains. The strains were isolated from clinical specimens and typed by the usual biochemical procedures. Square agar plates of 12 x 12 cm were divided into rectangular (2 x 3 cm) regions and spread with 0.5x 10(4) colony forming units (CFU)/ml of bacterial suspension. The excess liquid was removed and the plates were allowed to dry for 30 min. A total of 96 rectangular (2x3 cm) regions were used for each strain, in order to test an equal number of laser parameters. Each rectangular region was irradiated with different laser parameters, using a 193 nm ArF excimer laser, linked with a simple Galilean afocal system and a rectangular diaphragm of the same dimensions as the original laser beam cross-section, at a distance of 10 cm from the irradiated surface. This system was used in order to keep the laser pulse energy under 80 mJ and to cut-out the non-transverse electromagnetic mode branches of the laser beam. We then studied the bacterial survival ratio versus the number of laser pulses, the repetition frequency and the total laser beam fluence. Our results showed that the total laser beam fluence was the most important parameter to consider in evaluating the bactericidal effect of ArF excimer laser radiation. A critical value of the total fluence was determined for each strain, such that, for laser beam fluences greater than this critical value, no colonies appeared to survive while, for laser fluences less than this critical value, the survival ratio did not exceed 2 x 10(7) CFU (2 x 10(-5)%). These critical values were found to vary between 8 J/cm2 and 16 J/cm2 for the bacterial species studied. Under these conditions, ArF laser irradiation is promising for the sterilisation of hard surfaces and for in situ application.     

The protection of DNA in blood leukocytes from damaging action of ultraviolet radiation using the “Useful Sun” strategy

The damaging effects of light that was emitted by a DRSh250-3 mercury lamp on the DNA of mouse blood leukocytes was studied in vitro. It was shown that the main DNA damage is due to the action of UVB radiation (280–320 nm). Under the combined effects of the UV radiation and the orange–red fluorescent component it was found that the additional fluorescent light with the spectral maximum at 625 nm from nanoluminophore materials (quantum dots that are based on CdSe/ZnS, CdSe/CdS/ZnS) protected the cellular DNA from the damaging effect of UV radiation. Using nanomolar concentrations of hydrogen peroxide, the hypothesis of the role of reactive oxygen species in the protective effects of the red–orange light was tested in vitro. It was shown for the first time that the mechanisms of the protective effects are associated with the induction of an adaptive response by nanomolar concentrations of hydrogen peroxide that are induced by the orange–red light.     

<Emphasis Type="Italic">Isatis indigotica</Emphasis> seedlings derived from laser stimulated seeds showed improved resistance to elevated UV-B

Sterilized seeds of Isatis indigotica (Brassicacae) were divided into four groups based on irradiation pretreatments. These control groups (C) were non irradiated, He–Ne laser treated seeds (L), UV-B treated seeds (B) and He–Ne laser followed by UV-B radiation treated seeds (LB). Laser radiation was provided by He–Ne laser, UV-B radiation was provided by filtered Qin brand 30 W fluorescent sun lamps. Malondialdehyde (MDA), proline, UV-B absorbing compounds and ascorbic acid (AsA) concentrations, as well as, the activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were measured in the cotyledons of seedlings from all the four irradiation treatments. The result indicate that UV-B radiation enhanced the concentration of MDA while decreasing the activities of SOD, CAT, POD and the concentration of AsA in the seedlings compared with the controls. The concentration of MDA decreased, while the activities of SOD, CAT, POD and the concentration of AsA increased in seedling treated with He–Ne laser and UV-B compared to UV-B alone. The concentration of proline and UV absorbing compounds increased progressively with treatments i.e. UV-B irradiation, He–Ne laser irradiation, and He–Ne laser irradiation followed by UV-B irradiation compared to the controls. The present data suggest that Isatis indigotica seedlings derived from laser stimulated seeds showed improved resistance to elevated UV-B.     

Removal of bone cement with laser

In operations requiring replacement of cemented endoprothesis, the removal of both the prosthesis and the cement is often difficult as the cement adheres strongly to the bone. Mechanical removal frequently results in fenestration or traumatisation of the bone. The aim of non-contact removal of polymethylmethacrylate (PMMA) with the laser, is to access normally inaccessible regions while inflicting a minimum amount of damage to the bone substance. The much cited cw or superpulsed CO2-laser cannot be used clinically, due to the thermal stressing of the bone. The paper shows spectra of PMMA with and without dopants, e.g. Tinuvin as UV absorber, optical staining with a high-pressure mercury lamp at lambda = 275 +/- 25 nm, lambda = 350 +/- 25 nm and various radiation times, as well as with an excimer laser lambda = 248 nm, FWHM 20 ns, and ablation measurements were made with the following lasers: excimer laser, Lambda Physics, EMG 102, FWHM 25 ns, lambda = 351 nm, excimer laser, Technolas, MAX 10, FWHM 60 ns, lambda = 308 nm, and a pulsed CO2 laser from PSI, lambda = 9.2 and 10.6 microns, FWHM 130 and 65 microseconds, pulse peak power 3.8 and 7.7 kW. The excimer laser, pulse length less than 100 ns, is unsuitable for clinical use because the required removal rate cannot be achieved either with doped PMMA or with pure PMMA. More promising results have been obtained with the pulsed (microseconds range) CO2 laser which has a removal rate of up to 30 times that of the above-mentioned excimer laser, with significantly lower thermal stressing of the bone than with the cw or super pulsed CO2 laser.     

Phytochrome Control of Another Phytochrome-mediated Process

The phytochrome-mediated attachment of root tips of mung bean (Phaseolus aureus) and barley (Hordeum vulgare) to glass is affected by the prior exposure of hydrated seeds or seedlings to red or far red radiation. Prior irradiation of seeds or seedlings of mung bean with red light promotes attachment, while far red light promotes detachment of root tips. Similar exposure of barley seeds and seedlings to red light accentuates detachment, while far red light accentuates attachment of root tips. Red-far red light reversibility of the pretreatments indicates phytochrome control.     

He-Ne激光对增强UV-B辐射小麦幼苗多胺氧化酶和过氧化物酶活性的研究

采用He-Ne激光辐照对增强UV-B辐射后小麦幼苗的损伤修复作用进行了研究。小麦种子在盛有湿滤纸的培养皿内25℃下进行萌发。萌发后小麦幼苗在经10.08 kJ·m^-2·d^-1的增强UV-B辐射,然后再用5 mW·mm^-2的He-Ne激光进行辐照。通过小麦幼苗叶片游离脯氨酸含量、多胺氧化酶和过氧化物酶的活性变化,测定了He-Ne激光对小麦UV-B损伤的修复情况。结果表明,游离脯氨酸、多胺氧化酶、过氧化物酶的变化同小麦幼苗损伤的修复的能力相关联。He-Ne激光辐照可使由增强UV-B辐射后诱导叶片升高的游离脯氨酸含量降低。增强UV-B辐射对多胺氧化酶（PAO）活性和过氧化物酶（POD）活性呈促进的作用。辐射6 d后PAO和POD总的活性呈正相关性,PAO和POD活性都呈现B组最高,L组最低,且差异显著。显示He-Ne激光对两种酶由于增强UV-B辐照造成的伤害有一定的修复。     

XeCl 准分子激光辐照生物大分子对其结构影响初步研究-Ⅰ308 nm紫外激光辐照小牛胸腺DNA的电镜观察与分析

XeCl 308 nm紫外激光(单脉冲输出能量33.4 mJ,脉冲频率 2次/秒,辐照时间45秒,光斑6×3 mm,透镜焦距300 mm)辐照330 mm处小牛胸腺DNA(固体).用扫描电子显微镜和透射电子显微镜可以观察到DNA受照射后有断裂、分叉、扭曲、聚集和交联等现象,影响生物大分子的初级结构和高级结构的变化.在我们的实验条件下是以影响DNA构象变化为主.     

Zingiber pseudosquarrosum sp. nov. (Zingiberaceae) from Andaman and Nicobar Islands,India

Zingiber pseudosquarrosum L. J. Singh & P. Singh sp. nov. (Zingiberaceae) from Andaman and Nicobar Islands, India is described and illustrated and its conservation status is evaluated. This new species seems related to Z. squarrosum Roxb. but can be distinguished by the presence of a small pseudostem, long ligule and petiole, broadly lanceolate leaves with cuneate base, caudate apex and paxillate venation, urceolate or prolate inflorescences, very long underground peduncle, long calyx, very long corolla tube, labellum deep purple red (claret) at centre, orange red (vermillion) at lateral sides with ivory (off white) spots, tip truncate and slightly notched, margin folded back, stamen with short filament, yellow orange anther, light brown ovary, blood red (cinnabar) seeds covered by a white aromatic aril. A key to the species of Zingiber Mill. from the Andaman and Nicobar Islands is also provided.