氦氖激光血管内照射配合吗啡控制癌痛的对照观察

目的探讨氦氖激光血液照射辅助治疗控制癌痛的疗效。方法对52例中晚期癌症重度痛患者在使用口服吗啡治疗基础上加用低能量氦氖激光血液照射治疗1周后,对疼痛缓解程度及平均缓解时间进行对照观察。结果加用激光照射组的镇痛疗效优于单用吗啡组,P<0.05,有效率分别为92%和84%,P>0.05,显效率分别为67%和46%,u=2.07,P<0.05,均数缓解时间分别为(8±3)h和(8±4)h,t=0.78,P>0.05,差异无显著性意义。结论氦氖激光血液照射治疗有一定协同镇痛作用。     

Transmyocardial revascularization ameliorates ischemia by attenuating paradoxical catecholamine-induced vasoconstriction

Background  The mechanism by which transmyocardial revascularization (TMR) offers clinical benefit is controversial. We hypothesized that TMR ameliorates ischemia by reversing paradoxical catecholamine-induced vasoconstriction. Methods and Results  Chronic ischemic cardiomyopathy was created in 11 dogs by placing ameroid constrictors on the proximal coronary arteries and their major branches. Six weeks later, 35 channels were created percutaneously in the left circumflex artery region, with the left anterior descending artery region serving as control. At rest, wall thickening and myocardial blood flow did not change in the treated region, whereas they deteriorated in the control bed. Contractile and myocardial blood flow reserve increased in the treated region but deteriorated in the control region. There was diminished iodine 123 metaiodobenzylguanidine uptake and a significant reduction in noradrenergic nerves in the treated region compared with the control region, with a corresponding reduction in tissue tyrosine hydroxylase activity. Conclusions  We conclude that the absence of a catecholamine-induced reduction in MBF reserve and contractile reserve in the TMR-treated region with associated evidence of neuronal injury indicates that the relief of exercise-induced ischemia after TMR most likely results from reversal of paradoxical catecholamine-induced vasoconstriction. These findings may have implications in selecting patients who would benefit from TMR. Supported in part by grants from the National Institutes of Health (R01-HL66034 and K-08-HL074290-01). Bethesda. Md. The radio-labeled microspheres were provided by DuPont Pharmaceuticals, North Billerica. Mass, and the ultrasound equipment was supplied by Philips. Andover, Mass. Dr Leong-Poi was the recipient of a Fellowship Training Grant from the Canadian Institute of Health Research and the Heart and Stroke Foundation of Canada.     

脉冲Nd：YAG激光照射对大鼠炎症牙龈组织的作用

患实验性牙龈炎的大鼠牙龈（６例）经脉冲掺钕钇铝柘榴石激光（Ｎｄ：ＹＡＧ激光）照射后进行光镜及超微结构观察。目的在于了解低能量Ｎｄ：ＹＡＧ激光照射对牙龈炎症的治疗作用。炎症牙龈经输出能量为１．５Ｗ，脉冲数为２０ＰＰＳ的激光照射后与对照组相比较，形态学上有如下变化：上皮细胞无变性；牙龈上皮层数较炎症时减少；上皮下炎细胞浸润明显减少；上皮细胞间隙变小；上皮下结缔组织内产生大量的排列致密的胶原纤维。结果提     

Laser photobioactivation mechanisms: in vitro studies using ascorbic acid uptake and hydroxyproline formation as biochemical markers of irradiation response

Clinical investigations of laser photobioactivation, or biostimulation, might be differently designed and more fruitful if knowledge of basic biochemical mechanisms were better understood. In this investigation, biochemical events identified as responses to 904 nm irradiation included increased ascorbic acid uptake by fibroblasts. These cells also showed increased hydroxyproline formation, and this was increased several-fold by the addition of proline to the medium. Maximum biochemical responses were observed at a pulse frequency of 67 Hz and a pulse width of 150 nsec with an energy density of approximately 7 mJ/cm2 per exposure. Elements in the mitochondrial cytochrome system are proposed as the radiation absorbing chromophore(s). Hypothetically, the energy generated is linked to ascorbic acid uptake, which in turn stimulates collagen synthesis.     

Differential effects of short- and long-pulsewidth laser exposures on retinal ganglion cell response

Time-dependent effects of laser exposures on rhesus monkey retinal ganglion cells were studied with a Q-switched, doubled Nd:glass laser, which produced 20 nsec pulses of 530-nm light, and a continuous-wave (CW) argon laser (514.5 nm), which produced exposures of 0.1-msec to 0.1-sec duration. Ganglion cell activity was recorded in situ by means of an intraocular electrode. Ganglion cells exposed to a single 20-nsec exposure, at a sublesion intensity, produced a 60-90 sec discharge of action potentials and exhibited a 2 log or greater elevation of light threshold, depending on beam size and intensity. At equivalent energy levels, the longer exposures produced the same or slightly weaker effects. This result is not as straightforward as it seems. Submillisecond flashes bleach no more than 50% of the visual pigment because of photoregeneration. The Dowling-Rushton relation predicts that a 50% bleach should produce only a 1.5 log loss of cone sensitivity. Exposures longer than 1 msec should not photoregenerate pigment (ie, more pigment will be bleached for a given exposure intensity). In view of the probable differences in pigment bleaching, it appears that the Q-switched laser light adapts the cells out of proportion to the visual pigment actually bleached--a single-cell analogue of Rushton's "theta" effect.     

不同功率半导体激光对声带热损伤的比较

目的：探讨Diomed－25半导体激光不同功率对声带热损伤的程度,为临床应用激光治疗声带病变提供实验依据。方法：选用犬作为实验动物,选定激光功率分别为5、10、20W,照射时间为2s,以接触式照射活体犬的声带后,测量组织热损伤的浓度和宽度,并通过大体标本、光镜下观察声带局部损伤情况。结果：照射时间为2s,激光输出功率为5、10、20W时,其组织热损伤的深度分别为0．2－0．4、0．4－0．6、0．8－1．0mm;热损伤的宽度分别为1．0－1．7、1．7－2．0、2．0－2．6mm。在作用时间相同情况下,激光功率不同,对声带组织的热损伤程度有显（P＜0．05）。结论：选择合适功率的半导体激光对声带病变的治疗是安全、有效的。     

A prospective randomized trial comparing transurethral resection of the prostate and laser therapy in men with chronic urinary retention: The CLasP study

PURPOSE: We assessed the effectiveness of laser therapy versus transurethral prostatic resection in men with symptomatic chronic urinary retention secondary to benign prostatic enlargement. MATERIALS AND METHODS: This trial was multicenter, pragmatic and randomized. Analysis was done by intent to treat. Laser therapy involved neodymium:YAG noncontact visual prostate ablation, while transurethral prostatic resection was performed by standard electroresection. Patients were included in our study if they reported moderate to severe lower urinary tract symptoms with an International Prostate Symptom Score (I-PSS) of 8 or more, benign prostatic enlargement and a persistent post-void residual urine volume of more than 300 ml. Followup was 7.5 months. Primary outcome measures included the I-PSS, I-PSS quality of life score, maximum urinary flow and post-void residual urine volume. Secondary outcome measures included treatment failure, complications, hospital stay and catheterization time. RESULTS: A total of 82 patients agreed to be randomized to receive laser therapy (38) or transurethral prostatic resection (44). There were significant improvements in all primary outcomes in each group from randomization to followup. Transurethral prostatic resection was significantly better than laser therapy for I-PSS and maximum urinary flow values (p = 0.035 and 0.029, respectively) but there were no differences in post-void residual urine volume and I-PSS quality of life score between the groups. We noted significantly more treatment failures with laser therapy than resection (8 versus 0, p = 0.0014), although only 3 patients required resection after laser therapy because of persistent symptoms. In addition, hospital stay after resection was 2-fold that after laser therapy (ratio of geometric means 2.01, 95% confidence interval 1.54 to 2.61, p <0.0001). However, time to catheter removal was 9 times longer in the laser therapy group (p <0. 0001). Complication rates were significantly higher for transurethral prostatic resection (chi-square 5.05, 1 df, p = 0.025). CONCLUSIONS: Transurethral prostatic resection is more effective than laser ablation in men with chronic urinary retention in terms of symptom score, maximum urinary flow and failure. However, men who underwent resection had significantly more treatment complications and were hospitalized longer than those who received laser therapy. This finding implies that laser ablation therapy may have a role in patients at higher risk who are willing to accept a lower level of effectiveness in exchange for decreased complication rates and hospital stay.