The bactericidal activity of pulsed Nd-YAG laser radiation in vitro

Pulsed Nd-YAG laser irradiation of bacteria has been suggested as a possible means of treating contaminated intra-oral sites although relatively few studies have been conducted. In this investigation, the antimicrobial activity of a pulsed Nd-YAG laser was assessed in vitro for a range of oral bacteria using several pulse energies and exposure durations. Pure cultures of each organism were lased in saline suspensions followed by standard colony counting techniques for test and control samples. Microbial inhibition was found to be organism-dependent and varied with energy dose and pulse energy. For all nine test species 120-mJ laser pulses proved more efficient than 80-mJ pulses, with 99.9% kills compared with around 90% kills after exposure to 1800 pulses. These killing activity levels compare favourably with those achieved with other lasers in vitro.     

Erb:YAG and Hol:YAG laser ablation of meniscus and intervertebral discs.

Erb:YAG and Hol:YAG laser ablation rates of fibrocartilage and nucleus pulposus were measured in vitro simulating clinical conditions. After ablation macroscopic and microscopic appearance of the ablation site was investigated. Hol:YAG and Erb:YAG laser mean ablation rates increased almost linearly with rising energies, showing higher total ablation rates for the Hol:YAG laser due to its higher achievable energy density. At comparable energy densities the Erb:YAG laser appears to be more effective with respect to the corresponding ablation rates. Consequently, the ablational threshold proved to be lower for the Erb:YAG laser. Whereas during Hol:YAG laser ablation, some smoke formation and considerable tissue shrinking occurred, these effects could not be observed during Erb:YAG laser ablation. Consequently macroscopic and microscopic inspection showed some thermal damage after Hol:YAG and only minimal alterations after Erb:YAG laser ablation. Adjacent thermal damage was determined and proved to be lower for the Erb:YAG laser. In our opinion the characteristics of each laser system provide certain advantages for special clinical indications.     

Comparison between laser and electrical ablation of ventricle in dogs: Hemodynamic,pathologic and electrocardiographic observations

Summary To characterize and compare the pathologic, hemodynamic and electrocardiographic changes of both transeatheter laser and electrical energy on ventricle, 33 subendocardial myocardium lesions were induced at energy 60, 120 and 240 Joules by either transcatheter laser irradiation or electrical shock in 7 anesthetized dogs. The following results were observed: 1) Both laser and electrical ablation on myocardium created nonhomogeneous myocardium injury, but laser ablation caused mainly focal tissue vaporization and necrosis, while electrical shock induced widespread tissue degenerations; 2) Both laser and electrical induced-lesion dimensions increased parallel to the total dosage of energy; 3) Laser ablation caused mainly (90%) single ventricular premature beats and 86 % of them occurred within the first minute after energy discharged, while ventricular tachycardias were found in any electrical energy groups; ventricular fibrillations occurring during laser and electrical ablation were 5 % and 13 % respectively (P< 0.01): 4) A decrease in aortic blood pressure and an increase in central verous pressure induced by laser ablation were significantly less than that produced by the same amount of electrical energy (P<0.0l). Our preliminary results have shown that transeatheter laser ablation has great potential for becoming a practical method in the management of refractory tachycardias.     

输尿管镜钬激光治疗输尿管纤维上皮息肉14例报告

目的：探讨输尿管镜钬激光治疗输尿管纤维上皮息肉的有效性和安全性。方法：应用输尿管镜钬激光技术治疗输尿管纤维上皮息肉患者14例，其中上段息肉10例，中、下段息肉各2例，并发输尿管结石9例。结果：术后随访3个月，12例疗效满意，肾积水明显改善．保护了肾功能；1例发生输尿管狭窄．1例残留结石。结论：输尿管镜钬激光技术是治疗输尿管纤维上皮息肉安全、有效的方法，但远期疗效尚需进一步研究。     

准分子激光原位角膜磨镶术后界面性角膜炎的临床观察

目的 :动态观察准分子激光原位角膜磨镶术 (LASIK)后界面性角膜炎 (DLK)的临床变化 ,同时对其角膜瓣下临床特点及处理方法进行分析。　方法 :对 35 0 0例行LASIK后 1 0例 (1 8只眼 )发生DLK患者进行观察。按3、7、1 4天和 1、2、6个月不同时间进行视力、裂隙灯显微镜检查。　结果 :局部用激素、抗生素治疗 1周 ,症状控制 ,1～ 2个月全部吸收。视力恢复至 1 .0～ 1 .5 (1 6只眼 ) ,0 .8～ 1 .0 (2只眼 )。　结论 :LASIK后DLK常发生在术后 1～ 7天内 ,迟发者偶见 ,男性多于女性 ,以局部激素治疗为主 ,严重患者需全身激素加抗生素治疗。DLK早期须与角膜上皮植入、层间感染鉴别     

抗氧化剂对准分子激光兔角膜切削术后角膜组织的影响

目的 探讨局部应用抗氧化剂VitC、VitE对准分子激光屈光性角膜切削术(PRK)术后角膜组织的影响。方法 将24只实验免分成2组，每组12只，行双眼一5．0DPRK。一组术后左眼每日结膜下注射VitC0．1g，右眼为对照；另一组术后左眼每日结膜下注射VitE25mg，有眼为对照。于术后1、3、7、14天测定角膜组织超氧化物歧酶(super—oxide dismutase，SOD)、丙二醛(malondialdehyde，MDA)及谷肮甘肽过氧化物酶(glutathioneperoxNe，GSH—PX)的变化，观察其病理变化。结果 术后1、3天角膜SOD、GSH—Px活性小于对照组(P＜0．01)，MDA的水平高于对照组(P＜0．01)。局部应用抗氧化剂组其角膜SOD、GSH—PX活性高于单纯激光组(P＜0．01)，MDA水平低于单纯激光组(P＜0．01)。结论 准分子激光屈光性角膜切削术后，存在着氧自由基性的组织损伤破坏，局部应用VitC、VitE能降低角膜的自由基损伤。     

弱激光血疗法的发展及展望

本文主要介绍了弱激光血疗的机制及其在我国的发展过程.弱激光血疗法起源于前苏联的紫外光量子疗法,传入我国后经历了静脉内照射疗法,离体血液激光照射回输疗法,口咽部照射伴吸氧疗法,鼻腔内照射疗法等.本文对各种疗法的特点及临床应用进行了详细叙述.有些学者认为,中医的观点也能揭示激光血疗的机制.从中医辨证的角度,人的体质分为虚证和实证.结合中医针灸的虚则补之,实则泻之的原理,根据患者的虚实状况,采用含有中医补泻信息的调制激光照射血液,同时加照相关敏感穴位,促进疗效,以体现中医的辨证施治的原则可取得更好的疗效.     

595nm激光对兔耳瘢痕成纤维细胞增殖与凋亡的影响

目的：探讨595nmVbeam激光照射对增生性瘢痕动物模型伤口愈合过程中成纤维细胞增殖与凋亡的影响。方法：成年大耳白兔20只,建立兔耳腹侧面增生性瘢痕模型,对比研究在瘢痕形成过程中595nmVbeam激光照射对兔耳瘢痕成纤维细胞的影响,采用免疫组化方法检测增殖细胞核抗原（PCNA）蛋白表达和细胞凋亡的原位检测。结果：兔耳增生性瘢痕经595nmVbeam激光照射后,按不同时间段取材进行免疫组化染色并与对照组比较,高倍镜下观察结果,显示PCNA蛋白表达明显减弱,细胞凋亡增加。结论：595nmVbeam激光照射可抑制兔耳增生性瘢痕成纤维细胞的增殖过程,诱导细胞凋亡。应用595nmVbeam激光预防和治疗瘢痕是可行的。     

前列腺上皮内瘤变的基因微阵列分析

目的:通过基因微阵列分析,研究经显微切割后的前列腺上皮内瘤变(PIN)的基因表达谱,并将其与前列腺良性增生(BPH)及前列腺癌的mRNA基因表达谱进行对比,探讨前列腺癌的发生、发展,检测PIN及前列腺癌的肿瘤标志物。方法:采用美国Affymetrix公司的HG-U133A基因芯片,检测了16例人的前列腺组织标本,包括5例良性标本,6例PIN以及5例前列腺癌标本,均为新鲜冰冻组织。为了精确获得上皮细胞基因表达谱,避免周围间质细胞及单核细胞的RNA 对结果的影响,我们采用了激光捕获显微切割技术,分别得到了3组纯的上皮细胞群进行研究。结果:有些基因的表达强度在从良性增生到PIN到癌的转化过程中,呈逐渐改变的趋势,但笔者发现3组间基因表达谱存在非常显著的差异。与BPH及前列腺癌相比,PIN有其独特的基因表达谱。结论:基因表达谱中显著上调及下调的特异性基因,可以将PIN 和BPH及前列腺癌中区分开来;基因微阵列分析也有助于揭示代谢通路及信号转导途径的变化,有利于靶基因治疗。     

长脉冲Nd:YAG激光非侵入性治疗皮肤浅表静脉畸形

目的前瞻性研究长脉冲1064nm Nd:YAG激光非侵入性治疗皮肤浅表静脉畸形的疗效。方法22例不同部位皮肤浅表静脉畸形患者接受长脉冲1064nm Nd:YAG激光治疗,6mm直径光斑,7～8ms双脉宽,脉冲间隔20ms,140～150J/cm2能量,接触式冷却,治疗间隔3周至1个月,治疗后1、6个月随访,评价病灶清除率分为五级。结果22例患者完成治疗,最多治疗5次。随访6个月,96.3%浅表静脉畸形获得76%～100%的清除,37%获得病灶的完全清除,未见复发。治疗部位无一例发生紫癜,治疗后8例(38.1%)出现红斑,1d至1个月消退。无色素改变和形成。结论长脉冲1064nm Nd:YAG激光能有效安全地治疗皮肤浅表静脉畸形,选择性地清除浅表血管,并使用接触冷却系统保护表皮,减少紫癜发生及色素改变和瘢痕的形成,达到理想的美容效果。