Lasers in Medical Science

Published by Springer Nature

Online ISSN: 1435-604X


Print ISSN: 0268-8921


Treatment of trichostasis spinulosa with 0.5-millisecond pulsed 755-nm alexandrite laser
  • Article

August 2011


428 Reads


Trichostasis spinulosa (TS) is a follicular disorder in which multiple hairs in a keratinous sheath project above the skin surface. Current treatments provide temporary relief and side effects are common. We report the successful treatment of TS in 20 patients using a short-pulsed 755-nm alexandrite laser. The 20 patients (skin types II-V) presented with TS lesions on the tip of their nose. All patients received a single treatment (one to three passes) with the laser with cold air cooling but without anaesthesia or analgesia. Treatment parameters were as follows: pulse duration 0.5 ms, fluence 15-17 J/cm(2), and spot size 5 mm. The entire procedure required less than 5 min to perform. The patients were followed up for 3 months for any adverse effects or recurrence. In all patients the lesions disappeared immediately after treatment with minimal or no pain. Erythema was minimal and lasted 5-20 min in all patients. Patients were very satisfied. The treated areas were still clear 4 to 5 weeks later, and a second treatment was not considered necessary. There were adverse effects other than the erythema and there was no recurrence within the follow-up period of 3 months. A single treatment with a short-pulsed 755-nm alexandrite laser appears to be a rapid, minimally painful, and effective treatment for TS in patients of skin types II to V.

Fig. 1 Experimental set-up for sample irradiation. The dentine slices were fixed on a 5° inclined surface. The energy distributions in the beam cross section and on the slice surface are shown. The slices were irradiated at a distance of 4 cm between the handpiece and the sample surface to ensure the correct energy density 
Bactericidal effect of a Nd:YAG laser on Enterococcus faecalis at pulse durations of 15 and 25 ms in dentine depths of 500 and 1,000 μm
  • Article
  • Full-text available

August 2011


232 Reads






The success of endodontic treatment depends on the effective elimination of microorganisms from the root canal, and lasers provide more effective disinfection than conventional treatment using rinsing solutions. The objective of this in vitro study was to determine the bactericidal effect of laser irradiation in dentine of various depths at a wavelength of 1,064 nm and pulse durations of 15 and 25 ms. A total of 90 dentine slices were cut from bovine incisors and divided into two groups (45 slices each) of thickness 500 and 1,000 μm. All were inoculated with a suspension of Enterococcus faecalis (5.07 × 10(9) bacteria/ml). Based on the clinically accepted dose (approximately 300 J/cm(2)), the following laser settings were chosen for this study: 1.75 W, 0.7 Hz for 4 s, three repetitions. The two groups were divided into two subgroups of 15 slices each to be irradiated with pulse durations of 15 and 25 ms. The remaining 15 slices per group were not irradiated to serve as a control. After irradiation, the colony-forming units (CFU) were counted and evaluated. To determine the bactericidal effect of irradiation with different pulse durations, the results in the different groups were compared statistically. For all irradiated subgroups a bactericidal effect was observed at pulse durations of 15 and 25 ms (p=0.0085 and p<0.0001). The corresponding average log kills were 0.29 (15 ms) and 0.52 (25 ms) for 500 μm and 0.15 and 0.3 for 1,000 μm, respectively. The results of this in vitro study showed that Nd:YAG laser irradiation with a pulse duration of 15 ms eliminated an average of 49% and 29% of E. faecalis at dentine depths of 500 μm and 1,000 μm, respectively, and irradiation with a pulse duration of 25 ms eliminated 70% (500 μm) and 50% (1,000 μm). However, these values are lower than those achieved with the established protocol using microsecond pulses.

Our perspective of the treatment of naevus of Ota with 1,064-, 755- and 532-nm wavelength lasers

May 2013


120 Reads

Naevus of Ota (NO) is a disfiguring pigmentary disorder affecting the face. Q-switched neodymium-doped yttrium aluminium garnet (QS Nd:YAG)-1,064 nm is a standard laser treatment because it causes highly selective destruction of melanin within the aberrant dermal melanocytes. However, not all lesions respond. This study aims to evaluate the efficacy/safety of QS Nd:YAG-1,064 nm and the shorter wavelength QS Alexandrite-755 nm and QS Nd:YAG-532 nm lasers in treating NO. Data were evaluated from 21 patients treated in our laser centre from 2004 to 2012. Lesional skin was irradiated with QS-532 nm/QS-755 nm/QS-1,064 nm, with settings titrated according to responses. All received initial test patches to direct initial wavelength choice, with subsequent treatments at 3-monthly intervals until clearance/lack of further response. Laser modality was switched following repeated test patches if there was no or no sustained improvement. Two thirds of patients had ≥90 % improvement compared to baseline photographs. In 20 % of patients, QS-1,064 nm was most efficacious with 97 % mean improvement. The mean improvement was 80 % for those in whom QS-755 nm was superior, and 90 % for QS-532 nm. Median number of overall laser treatments was 8 (range 4-13). Number of treatments required varied significantly according to lesional colour and site: grey lesions and those on the forehead/temple were most resistant. We confirm successful treatment of NO with QS Nd:YAG-1,064 nm and the shorter wavelength QS-755 nm/QS-532 nm lasers without serious or irreversible side effects. We recommend judicious test patch analysis before treatment and a modality switch if complete clearance is not obtained.

Nd:YAG lasers (1,064 nm) in the treatment of venous malformations of the face and neck: Challenges and benefits

July 2007


313 Reads

Neodymium:yttrium aluminum garnet (Nd:YAG) laser therapy for venous malformations (VMs) of the head and neck is a rather new therapeutical option in addition to sclerotherapy and surgery. One hundred forty-six patients (age 2 months to 77.5 years) with VMs in the head/neck (localized, diffuse, and multifocal) were retrospectively analyzed with regard to number and quality of treatments and laser parameters used. Of these patients, 72 had no prior treatment of any kind, and 74 were pretreated. Laser treatment of mucosa and tongue was done with a mean fluence of 103.1 J/cm(2), of skin with 90.7 J/cm(2), and of glomuvenous malformations with 81.2 J/cm(2). Complex VM can mostly be controlled but rarely cured. Initial Nd:YAG laser therapy is important in the treatment of VMs regarding shrinkage of the tissue, discoloration, and induction of the desired dermal fibrosis that facilitates the surgical handling of the skin and reduces the risk of skin loss in surgery and sclerotherapy.

Table 1 The number of micronucleated cells in the buccal mucosa 
Table 2 Statistics of the groups 
Cytomorphological changes in buccal mucosa of patients treated with low-level 1,064-nm laser radiation

June 2011


49 Reads

The aim of this study was to examine the cytomorphological changes occurring in the buccal mucosa in patients treated with low-level 1,064-nm laser radiation. Seventeen individuals (12 males, five females) 18-24 years of age were included in the study. Low-level 1,064-nm laser radiation was applied to the right buccal mucosa near the premolar region; this therapy was repeated for 10 days. Buccal epithelial cells were collected from the right and left premolar regions of the individuals with a brush before and after therapy. The specimens collected from the left side were measured cytomorphometrically and used for the control group. Student's t test was used for statistical comparison of the values of the buccal epithelial cells collected from individuals; a p value < 0.05 was considered statistically significant. None of the patients showed any adverse reactions to the low-level 1,064-nm laser radiation therapy during application. There was no cytogenetic damage to the therapied or non-therapied regions in the buccal mucosa cells, as determined cytomorphologically. The results suggest that low-level 1,064-nm laser radiation therapy has no genotoxic potential. Within the limitations of this study, it can be concluded that low-level 1,064-nm laser radiation therapy may be used safely in dental treatments.

Effects of the 532-nm and 1,064-nm Q-switched Nd:YAG lasers on collagen turnover of cultured human skin fibroblasts: A comparative study

September 2010


131 Reads

Cultured human skin fibroblasts were irradiated twice successively with the 1.5 J/cm(2) of 532-nm and 1,064-nm lasers, respectively. The mRNA of procollagen, matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), heat-shock protein 70 (Hsp70), interleukin-6 (IL-6) and transforming growth factor beta (TGF-beta) were analyzed at 24 and 48 h post-irradiation by using RT-PCR. Both lasers significantly increased the expression of type I and III procollagen, TIMP1, and TIMP2, but decreased MMP1 and MMP2 expression. The 1,064-nm laser initiated TGF-beta expression while the 532-nm laser elicited the increase of Hsp70 and IL-6. The increase/decrease rates of procollagen, TIMPs and MMPs for the 1,064-nm laser were higher than that of the 532-nm laser. Thus, both lasers effectively accelerated collagen synthesis and inhibited collagen degradation. Collagen synthesis induced by the 1,064-nm laser might be partly due to the upregulation of TGF-beta expression, while the increase of Hsp70 and IL-6 might be partly responsible for collagen synthesis stimulated by the 532-nm laser. With the parameters used in this study, the 1,064-nm infrared laser is more effective in promoting the beneficial molecular activities than the 532-nm visible laser.

Effect of 1,064-nm Nd:YAG laser therapy on GCF IL-1β and MMP-8 levels in patients with chronic periodontitis

May 2011


79 Reads

The aim of this study was to evaluate the long-term effects of a combined periodontal treatment of scaling and root planing (SRP) and Nd:YAG laser (NDL) in chronic periodontitis (CP) patients. This was accomplished by determining the periodontal indices and the interleukin-1beta (IL-1β) and matrix metalloproteinase-8 (MMP-8) levels of the gingival crevicular fluid (GCF). This study was performed according to a random split-mouth-design, controlled clinical trial for sulcular debridement on 40 teeth from 20 patients with generalized moderate chronic periodontitis. The periodontal healing outcomes were compared after periodontal treatment with either SRP + NDL at 1 W (test side) or SRP (control side). Plaque index (PI), gingival index (GI), probing pocket depth (PPD), and clinical attachment level (CAL) were recorded, and samples of gingival crevicular fluid (GCF) were taken at baseline and post-therapy (3 and 9 months after treatment). The GCF samples were analyzed for IL-1β and MMP-8. There was postoperative improvement of all clinical parameters in both groups, but test side GI, PPD, and CAL recovery was higher than that of the control side (p < 0.05). Although levels of IL-1β and MMP-8 in GCF after treatment were lower in the test side than the control side, there was not a statistically significant difference (p > 0.05). In the long term, we found that SRP + NDL treatment of periodontal pockets was more effective than SRP alone in reducing PPD, CAL, GI, and GCF values.

Hereditary haemorrhagic telangiectasia treated by pulsed neodymium:yttrium-aluminium-garnet (Nd:YAG) laser (1,064 nm)

December 2007


41 Reads

Hereditary haemorrhagic telangiectasia (HHT) is a familial, autosomal, dominant, multi-system, vascular, dysplasia. Besides repetitive epistaxis, cutaneous eruptive macules and nodules lead to recurring bleeding and cosmetic problems. We report on a pilot study of four cases of HHT in which cutaneous lesions were treated with a pulsed neodymium:yttrium-aluminum-garnet (Nd:YAG) laser (1,064 nm). Pulsed Nd:YAG laser treatment, without anaesthesia, was performed several times on eruptive angiomas on palmar and facial skin. Lesions on fingers and face mostly showed very good, or even complete, clearing after the first laser treatment. Several macules required multiple treatment; only a few lesions showed no effect. Pulsed Nd:YAG laser therapy (1,064 nm) appears to be an effective and safe treatment option for hereditary haemorrhagic telangiectasia on the skin of face and extremities.

Effects of laser irradiation at different wavelengths (660, 810, 980, and 1,064 nm) on mucositis in an animal model of wound healing

May 2013


601 Reads

The aim of the present study was to compare the effectiveness of four different laser wavelengths (660, 810, 980, and 1,064 nm) used for low-level laser therapy (LLLT) on the healing of mucositis in an animal model of wound healing by investigating the expression of platelet-derived growth factor (PDGF), transforming growth factor beta (TGF-β), and blood-derived fibroblast growth factor (bFGF). Thirty-five male Wistar albino rats with a weight of 250-300 g body mass and 5 months old were used in the study. All animals were intraperitoneally injected with 100 mg/kg of 5-fluorouracil (5-FU) on the first day and 65 mg/kg of 5-FU on the third day. The tip of an 18-gauge needle was used in order to develop a superficial scratching on the left cheek pouch mucosa by dragging twice in a linear movement on third and fifth days. After ulcerative mucositis were clinically detected on the animals' left cheek pouch mucosa, the laser therapy was started. Four different laser wavelengths (660 nm, HELBO, Bredent; 810 nm, Fotona XD, Fotona; 980 nm, ARC Fox; and 1,064 nm, Fidelis Plus 3, Fotona) used for LLLT at ED 8 J/cm(2) daily from the first to the fourth days. Oval excisional biopsy was taken from the site of the wound, and the expression of PDGF, TGF-β, and bFGF was evaluated. The obtained data were analyzed by one2-way ANOVA, and then Tukey HSD tests were used for pairwise comparisons among groups (α = 0.05). The one-way ANOVA test indicated that expression values of the growth factors, PDGF and bFGF, were significantly affected by irradiation of different wavelengths of lasers (p < 0.001). However, expression value of the TGF-β was not affected by irradiation of different wavelengths of lasers (p > 0.05). The highest PDGF expression was detected in neodymium-doped yttrium aluminum garnet (Nd:YAG) laser group (p < 0.05), and there were no statistically significant differences among the other groups (p > 0.05). The highest bFGF expression was detected in 980-nm diode and Nd:YAG laser groups (p < 0.05), and there were no statistically significant differences among the other groups (p > 0.05). These findings suggest that low-level Nd:YAG and 980-nm diode laser therapy accelerate the wound healing process by changing the expression of PDGF and bFGF genes responsible for the stimulation of the cell proliferation and fibroblast growth.

The 1,318-nm diode laser supported partial nephrectomy in laparoscopic and open surgery: Preliminary results of a prospective feasibility study

March 2011


30 Reads

Warm ischemia (WI) and bleeding during laparoscopic partial nephrectomy (LPN) place technical constraints on surgeons. Our aim was to develop a safe and effective laser-assisted LPN-technique without the need for WI. In this study, a diode laser-emitting light at a wavelength of 1,318 nm at output powers between 45 and 70 W in continuous-wave mode was used. Light was coupled into a flexible 600-μm bare fiber to be transported to the tissues. After dry lab experience, 13 patients (six males, seven females) underwent five open and eight laparoscopic/retroperitoneoscopic partial nephrectomies. Postoperative renal function and serum C-reactive protein (CRP) were monitored and coagulation depth and effects on resection margins (RR) were evaluated. Demographic, clinical, and follow-up data are presented. Mean operative time was 116.5 min (range 60-175 min) with mean blood loss of 238 ml (range 50-600 ml). Laser light application took a maximum of 17 min. All patients had a favorable outcome. The locations of the treated tumors (eight left and five right) were central (two), upper pole (two), lower pole (three) and middle kidney parenchyma (six anterior, two posterior, and five peripheral). Mean tumor size was 3.3 cm (range 1.8-5 cm). Two WI (19 and 24 min) were needed. Immediate postoperative serum creatinine and CRP were elevated within 0.1 to 0.6 mg/dl (mean 0.18) and 2.1-10 mg/dl (mean 6.24), respectively. Coagulation depth ranged from <1 to 2 mm without an effect on histopathological evaluation of tumors or RR. One patient had positive RR. During follow-up (2-6 months), one patient developed an A-V fistula that needed embolization. This prospective in-vivo feasibility study showed that the diode laser is a safe and promising device for LPN. Its advantages are minimal gas formation, good hemostasis, and minimal parenchymal damage. Oncological safety appears to be warranted by the use of a diode laser.

Fig. 1 
Table 2 The number of fibroblasts in mouse skin of experimental and control groups. The data are expressed as means ± standard deviations
The role of mast cells in non-ablative laser resurfacing with 1,320 nm neodymium:yttrium-aluminium-garnet laser

July 2009


143 Reads

The aim of this study was to investigate the role of mast cells in mechanisms of collagen remodelling induced by non-ablative laser treatment. The dorsal skin of Kunming (KM) mice was exposed to 1,320 nm neodymium-yttrium- aluminium garnet (Nd:YAG) laser weekly for four consecutive weeks. Biopsies were taken 1 h after irradiation and 1 day, 7 days, 14 days, 30 days and 60 days after the first treatment. Skin samples were studied for mast cells, fibroblasts, and type I and III collagen, by toluidine blue, haematoxylin-eosin (HE) and immunohistochemical staining, respectively. The total number of mast cells in the skin of experimental group was significantly greater than that in the control at 1 h, 1 day, 21 days and 60 days after the first treatment (P<0.05, respectively). At any of the time points studied, the number of degranulated mast cells in the experimental group was significantly higher than in the control (P< 0.01, P<0.01, P<0.05, P<0.01, P<0.05, P<0.05, respectively). The number of fibroblasts in the experimental group exhibited a significant increase in comparison with those in control skin at days 7, 21, 30 and 60 after irradiation (P<0.05, P<0.01, P<0.01, P<0.05, respectively). The amount of type I collagen was significantly higher than in the control from day 21 to day 60 (P<0.05, P<0.01, P<0.01, respectively), and type III collagen showed a marked increase between day 7 and day 60, compared with the control (P<0.01, P<0.05, P<0.01, P< 0.01, respectively). There was a significant positive correlation between the number of fibroblasts and granulated mast cells (r=0.549, P<0.01). The amount of type I and III collagen also showed significant positive correlations with the number of degranulated mast cells (r=0.555, P<0.01 and r=0.579, P<0.01, respectively). The results suggested that dermal mast cells might be involved in the inflammatory response, fibroblast proliferation and collagen remodelling induced by non-ablative laser treatment.

Fig. 1. Clinical photographs of PWS located on the chest ( A ), the 
Fig. 2. Clinical photographs of a patient suffering from a facial PWS ( a ) at fi rst consultation (already pretreated at another clinic) and ( b ) after multiple full lesion dye laser sessions (in our clinic). Due to dye laser resistance IPL treatment was performed. c : Clinical setting after a single IPL treatment. 
Fig. 3. a : Treatment results of primary treatment. Primary IPL and LPDL treatments yielded better results than primary SPDL treatments, the difference between IPL treatments and SPDL treatments was signi fi cant ( P < 0.05). Clearance was rated as excellent ( > 75%, score 5), good (51 – 75%, score 4), fair (25 – 50%, score 3), bad ( < 25%, score 2), or no clearance (score 1) (* P < 0.05). b : Treatment results of pretreated PWS. IPL follow- up treatments yielded signi fi cantly better results as compared to SPDL follow-up treatments ( P < 0.05). LPDL primary treatments showed signi fi cantly better results than LPDL follow-up treatments ( P 1⁄4 0.043). In analogy, primary IPL treatments yielded signi fi cantly better results than follow-up IPL treatments ( P 1⁄4 0.004). No other statistically signi fi cant differences could be detected. Clearance was rated as excellent ( > 75%, score 5), good (51 – 75%, score 4), fair (25 – 50%, score 3), bad ( < 25%, score 2), or no clearance (score 1) (* P < 0.05). 
Experience with non-ablative fractional photothermolysis with a dual-mode laser device (1,440/1,320 nm): No considerable clinical effect on hypertrophic/acne scars and facial wrinkles

February 2011


234 Reads

In the literature, non-ablative fractionated photothermolysis (nFP) is accredited with improvement of wrinkles and scars combined with a reduced downtime. The purpose of this work was to evaluate the impact of a combination laser (1,320/1,440 nm) for nFP on hypertrophic scars, acne scars, and facial wrinkles. Thirty-six patients suffering from hypertrophic scars (n = 7), acne scars (n = 9), and wrinkles (n = 20) were treated using a combination Nd:YAG laser [λ(em) = 1,320 and 1,440 nm, pulse duration: 3-ms single pulse, fluence: 8.0-9.0 J/cm(2) (1,320 nm); 2.0-2.5 J/cm(2) (1,440 nm)]. The appearance of the treated condition was evaluated in a retrospective study by two blinded investigators based on follow-up photographs and by patient self-assessment. The frequency of side-effects was also assessed. Both patients and blinded observers rated the treatment results for hypertrophic scars and acne scars as slight improvement, and for wrinkles as equal as compared to baseline. No serious side-effects were reported. The light device used did not lead to a considerable clinical improvement of hypertrophic scars, acne scars, or wrinkles in this study.

Effects of the 1,320-nm Nd:YAG laser on transepidermal water loss, histological changes, and collagen remodeling in skin

September 2006


30 Reads

The goal of the study is to investigate the effects of the 1,320-nm Nd:YAG laser on skin barrier function and dermal remodeling. Forty-eight female mice were irradiated with the 1,320-nm laser four times at an interval of 1 week (350 micros, 10 mm, single pass 10% overlap). Three doses were used: 18, 22, and 26 J/cm2. Transepidermal water loss (TEWL) was measured at day 0, 1, 7, 21, 30, and 60 after treatments. Skin biopsies were taken to observe the changes in dermal structures and quantify the increases in the number of fibroblasts and collagen content. The dose of 22 J/cm2 induced the lowest ratio of TEWL (0.58+/-0.06, p < 0.05), highest degree of fibroblast proliferation (45.68+/-5.70, p < 0.05), and the most increase in type I collagen fibers (49.8%, p < 0.05) and hydroxyproline content (85.7%, p < 0.05). The dose of 26 J/cm2 caused marked inflammatory infiltration and the most increase in type III collagen fibers. The increase of type I collagen fibers was greater than type III collagen fibers for all three doses (p < 0.05). Our results demonstrated that 22 J/cm2 was most effective in enhancing skin barrier function and stimulating new collagen synthesis. Dermal remodeling after the 1,320-nm laser was mainly through the synthesis and deposition of collagen type I. Inflammatory reactions were in favor of the formation of type III collagen.

Temperature profiles of 980- and 1,470-nm endovenous laser ablation, endovenous radiofrequency ablation and endovenous steam ablation

November 2013


790 Reads

Endovenous thermal ablation (EVTA) techniques are very effective for the treatment of varicose veins, but their exact working mechanism is still not well documented. The lack of knowledge of mechanistic properties has led to a variety of EVTA protocols and a commercially driven dissemination of new or modified techniques without robust scientific evidence. The aim of this study is to compare temperature profiles of 980-and 1,470-nm endovenous laser ablation (EVLA), segmental radiofrequency ablation (RFA), and endovenous steam ablation (EVSA). In an experimental setting, temperature measurements were performed using thermocouples; raw potato was used to mimic a vein wall. Two laser wavelengths (980 and 1,470 nm) were used with tulip-tip fibers and 1,470 nm also with a radial-emitting fiber. Different powers and pullback speeds were used to achieve fluences of 30, 60, and 90 J/cm. For segmental RFA, 1 cycle of 20 s was analyzed. EVSA was performed with two and three pulses of steam per centimeter. Maximum temperature increase, time span of relevant temperature increase, and area under the curve of the time of relevant temperature increase were measured. In all EVLA settings, temperatures increased and decreased rapidly. High fluence is associated with significantly higher temperatures and increased time span of temperature rise. Temperature profiles of 980- and 1,470-nm EVLA with tulip-tip fibers did not differ significantly. Radial EVLA showed significantly higher maximum temperatures than tulip-tip EVLA. EVSA resulted in mild peak temperatures for longer durations than EVLA. Maximum temperatures with three pulses per centimeter were significantly higher than with two pulses. RFA temperature rises were relatively mild, resulting in a plateau-shaped temperature profile, similar to EVSA. Temperature increase during EVLA is fast with a high-peak temperature for a short time, where EVSA and RFA have longer plateau phases and lower maximum temperatures.

Fig. 1 A typical deconvoluted OCT signal versus depth of a layer deposited on a fibre tip. The vertical axis is the amplitude signal and the horizontal axis is the depth. The red lines indicate the region of interest of the fit to Eq. 1. The maximum layer thickness, d max , was determined from the full-width at half-maximum (FWHM). The distance between the pixels (white squares) is 4.3 µm, based on a layer of assumed refractive index of 1.5 
Table 1 Fibre number, EVLA wavelength, laser power, total delivered energy, and measured transmission at 1,310 nm 
Fig. 2 Transmission of 13 fibres in the 450 to 950 nm band. a Fibres 1-4 were used clinically at 810 nm. b Fibres 11 and 12 were used clinically at 940 nm. c Fibres 17-23 were used clinically at 1,470 nm 
Fig. 3 Transmission of 23 fibres in the 950 to 1,650 nm band. a Fibres 1-8 were used clinically at 810 nm. b Fibres 9-15 were used clinically at 940 nm. c Fibres 16-23 were used clinically at 1,470 nm 
Fig. 5 Tip of EVLA fibre 20 used at 1,470 nm photographed through a microscope; the fibre diameter is 0.6 mm. a Overview (×10). Two damaged areas (1 and 2) are indicated. b Artist's impression. Black arrow indicates the direction of view indicated in a. The red arrows point to areas 1 and 2. c Image focused on irregular and cracked area 1 (×20). d Image focused 29 μm lower than c on area 2 (×20) 
Carbonized blood deposited on fibres during 810, 940 and 1,470 nm Endovenous laser ablation: thickness and absorption by optical coherence tomography

February 2010


389 Reads

Endovenous laser ablation (EVLA) is commonly used to treat saphenous varicosities. Very high temperatures at the laser fibre tip have been reported during EVLA. We hypothesized that the laser irradiation deposits a layer of strongly absorbing carbonized blood of very high temperature on the fibre tip. We sought to prove the existence of these layers and study their properties by optical transmission, optical coherence tomography (OCT) and microscopy. We analysed 23 EVLA fibres, 8 used at 810 nm, 7 at 940 nm and 8 at 1,470 nm. We measured the transmission of these fibres in two wavelength bands (450-950 nm; 950-1,650 nm). We used 1,310 nm OCT to assess the thickness of the layers and the attenuation as a function of depth to determine the absorption coefficient. Microscopy was used to view the tip surface. All fibres showed a slightly increasing transmission with wavelength in the 450-950 nm band, and a virtually wavelength-independent transmission in the 950-1,650 nm band. OCT scans showed a thin layer deposited on all 13 fibres investigated, 6 used at 810 nm, 4 at 940 nm and 3 at 1,470 nm, some with inhomogeneities over the tip area. The average absorption coefficient of the 13 layers was 72 +/- 16 mm(-1). The average layer thickness estimated from the transmission and absorption measurements was 8.0 +/- 2.7 microm. From the OCT data, the average maximal thickness was 26 +/- 6 microm. Microscopy of three fibre tips, one for each EVLA wavelength, showed rough, cracked and sometimes seriously damaged tip surfaces. There was no clear correlation between the properties of the layers and the EVLA parameters such as wavelength, except for a positive correlation between layer thickness and total delivered energy. In conclusion, we found strong evidence that all EVLA procedures in blood filled veins deposit a heavily absorbing hot layer of carbonized blood on the fibre tip, with concomitant tip damage. This major EVLA mechanism is unlikely to have much wavelength dependence at similar delivered energies per centimetre of vein. Optical-thermal interaction between the vein wall and the transmitted laser light depends on wavelength.

Ex vivo and in vivo investigations of the novel 1,470 nm diode laser for potential treatment of benign prostatic enlargement

August 2008


49 Reads

Perioperative haemorrhage is still the major complication of transurethral resection of the prostate (TURP) for benign enlargement of the prostate. Photoselective vaporisation of the prostate (PVP) with the potassium-titanyl-phosphate (KTP) laser has been shown to achieve instant tissue ablation with excellent haemostatic properties. Our aim was to determine the tissue removal capacity, coagulation and haemostatic property of the novel 1,470 nm diode laser, ex vivo and in vivo. We evaluated two prototype diode laser systems at 1,470 nm in an ex vivo, isolated, blood-perfused, porcine kidney model (n = 5; 10 W-50 W) and in an in vivo investigation of beagle prostate (n = 4; 100 W) to assess vaporisation capacities and coagulation properties at different generator settings. The diode laser evaluation was compared with an 80 W KTP laser in the porcine model. After the laser treatment we performed a histological examination to compare the depth of coagulation and vaporisation. The diode laser system (50 W) showed significantly lower (P < 0.0001) capacities for tissue removal than the 80 W KTP laser (0.96 mm +/- 0.17 mm and 5.93 mm +/- 0.25 mm, respectively, P < 0.0001), while coagulation zones were significantly (P < 0.001) larger in diode laser-treated kidneys (3,39 mm +/- 0.93 mm and 1.27 mm +/- 0.13 mm, respectively). In vivo, the diode laser displayed rapid ablation of prostatic tissue with no intraoperative haemorrhage. Histological examination revealed coagulation zones of 2.30 mm (+/-0.26) at 100 W in the diode laser-treated prostates.

Fractional nonablative 1,540-nm laser resurfacing of atrophic acne scars. A randomized controlled trial with blinded response evaluation

September 2010


422 Reads

The efficacy of nonablative fractional laser resurfacing of acne scars has been described in case reports and uncontrolled trials. The present study is the first randomized controlled trial in this field. The aim of this study was to examine the efficacy and adverse effects of 1,540-nm nonablative fractional laser treatment of acne scars. Ten patients with acne scars were included. Two intraindividual areas of similar size and appearance within contralateral anatomical regions were randomized to (1) 3-monthly laser treatments with a StarLux 1,540-nm fractional handpiece, and (2) no treatment. Blinded on-site clinical evaluations were performed before treatment, and at 4 and 12 weeks after the final treatment. End-points were overall change in scar texture (from score 0, even texture, to 10, worst possible scarring), adverse effects, change in skin colour (from score 0, absent, to 10, worst possible), and patient satisfaction (from score 0, no satisfaction, to 10, best imaginable satisfaction). Before treatment, scars were moderately atrophic and uneven in texture on both treated and untreated sides (median score 6.5, interquartile range 4.5-8; P=1). After treatment, laser-treated scars appeared more even and smooth than untreated control areas (4.5, 2-6.5, versus 6.5, 4.5-8, P=0.0156, at 4 weeks; 4.5, 2.5-6.5, versus 6.5, 4.5-8, at 12 weeks; P=0.0313). Patients were satisfied with the treatment (5.5, 1-7, after 12 weeks) and five of the ten patients evaluated their acne scars as moderately or significantly improved. No differences were found in skin redness or pigmentation between before and after treatment. Patients experienced moderate pain, erythema, oedema, bullae, and crusts. No adverse effects were seen in untreated control areas. The nonablative 1,540-nm fractional laser improves acne scars with a minimum of adverse effects.

Fig. 1a-e The prototype vessel compressor used in the study seen in action on a volunteer subject. a Component parts of the compressor; b-d shows the piston inserted in the O-ring pressing the treatment area. When piston is removed the O-ring maintains pressure at the time that the laser is pulsed (e) 
Table 1 Age, skin type and vessel diameter of patients 
Fig. 2 Bar graph showing the patient SI scores expressed as a percentage compared for the 4-week and 8-week assessments 
Fig. 3 Bar graph showing objective clinician assessment of treatment efficacy for the items examined compared for the 4-week and 8-week assessments 
Fig. 6a, b Schematic illustrating the wound healing process after treatment of small leg veins with the 810 nm laser. a Region of mild coagulation formed over a coagulated vessel. b Formation of mildly fibrotic tissue produced by wound healing absorbs light from the treated vessel, thus helping to disguise the vessel from the macroscopic aspect 
An 810 nm diode laser in the treatment of small (≤ 1.0 mm) leg veins: A preliminary assessment

August 2004


562 Reads

A consistently effective treatment for small leg veins (< or = 1.0 mm) is still being sought. The efficacy of an 810 nm diode laser in vein removal was assessed in a preliminary study. Fifteen females, skin types I to III, vein diameters 0.5-1 mm, aged from 25 to 42 years, participated in the study. An 810 nm diode laser (90 W, 20 ms/pulse, 10 Hz rep rate, 4.0 mm hand piece) was applied along the target veins. Biopsies were taken from two patients before and after the first treatment session. No compression was applied post-treatment. Four weeks later, a second treatment was given. Results were assessed subjectively from the patients' satisfaction index (SI) and objectively from clinical photography done by an independent clinician, who also judged the venous morphology before and 4 weeks after the second session. All patients completed the trial. Pain was moderate to severe at the time of treatment and erythema which was mild, which was seen in all 15 patients; oedema occurred in 12 patients and blistering in only one. No scarring was noticed. The overall satisfaction indices at the 4- and 8-week assessments were 20.7% and 55.1%, respectively. No patient got worse. The objective evaluations at the 4- and 8-week assessments showed increasing improvement in all aspects examined. Pain at the time of treatment was a problem for all patients, so epidermal cooling should be added. Despite this, the 810 laser diode was an interesting and promising device for treatment of small leg veins, warranting further study in larger patient cohorts with a longer-term follow up.

Optimal and safe treatment of spider leg veins measuring less than 1.5mm on skin type IV patients, using repeated low-fluence Nd:YAG laser pulses after polidocanol injection

August 2012


109 Reads

Treatment of micro-veins of less than 1.5 mm with laser and with chemical sclerosis is technically challenging because of their difficulty to remedy. Laser treatment is even more difficult when dark phototypes are involved.Three groups of 30 patients each, skin type IV, and vessels measuring less than 1.5 mm in diameter, were enrolled for two treatment sessions 8 weeks apart: group A, polidocanol (POL) micro-foam injection; group B, Nd:YAG laser alone; and group C, laser after POL injection. Repeated 8-Hz low-fluence pulses, moving the hand piece over a 3-cm vein segment with an average of five laser passes maximum and with a total time irradiation of 1 s were used. Sixteen weeks after the second treatment, statistically, degree of clearance after examining photographs and patients satisfaction index, plotted on a visual analogue scale and comparing results of all three groups, results were significantly better for group C (p < 0.0001). No significant differences in complications were noticed between the three groups. Efficacy of combining POL and laser proved safe and satisfactory in 96 % of patients using low-fluence laser pulses with a total cumulative energy in the 3 cm venous segment, lower than that of conventional treatment. Very few and transient complications were observed. POL foam injection followed by laser pulses is safe and efficient for vein treatment in dark-skinned patients.

Fig. 2 Time period (min) needed for the different nephron-sparing operation scenarios ( “ § ” not significant – “ * ” significant t <0.05) 
Fig. 4 Histology (H&E staining) taken directly after tissue dissection (top) and after 43 days survival period (bottom). Bars indicate 1 mm
Comparison between a 1.92-μm fiber laser and a standard HF-dissection device for nephron-sparing kidney resection in a porcine in vivo study

July 2011


128 Reads

Nephron-sparing surgery was performed in a porcine model with a 1.92-μm fiber laser dissection device in comparison to a standard high-frequency dissection device. In nine pigs, general anesthesia and a median laparotomy were performed to expose both kidneys. On six kidneys (three HF and three laser) a partial renal parenchyma resection of the lower pole without opening of the renal pelvis was performed (group A). On 12 kidneys (four HF and eight laser), a hemi nephrectomy with opening of the renal pelvis was performed (group B). Total resection time including hemostasis of the remaining tissue was 501 ± 394 s in group "A-laser " vs. 176 ± 139 s in group "A-HF". For the group "B", the total resection time was 1174 ± 501 s (B laser) vs. 960 ± 407 s (B-HF). Blood loss was 28 ± 22 ml in group "A laser " vs. 15 ± 15 ml in group "A-HF". In group "B", the blood loss was 98 ± 73 ml (B laser) vs. 137 ± 118 ml (B-HF). No ischemic time for the kidneys was needed in group "A" for both dissection devices. In group "B", ischemia of the kidneys was performed three times during the eight laser procedures (420 ± 60 s) and only once at the four HF procedures (1,260 s). Healing process was observed over 4-6 weeks, survival rate was 100%, and no renal fistulas were found after the survival period. In conclusion, no significant differences were found between the compared dissection devices. However, the laser system with the flexible transmission fiber may have an advantage for a laparoscopic approach by steerable instruments.

Fig. 1 Macroscopic appearance of the exposed enamel after the pH- cycling challenge. Note the white spot lesions around the orthodontic brackets 
Fig. 2 Representative scanning electron micrographs of the enamel surfaces after the treatments. There were three patterns of enamel morphology after the treatments, as follows: a the enamel presents the morphology similar to that of normal enamel exhibiting superficial undulations with parallel grooves, observed in the G1, G4, and G5; b the enamel surface depicts a melting-like appearance, with pores of different diameters covered by a network of anastomosing circles, and semicircles protruding from the surface, observed in the Nd: YAG laser irradiation (G2); c the enamel surface also presents a melting-like appearance; however, the pores are apparently deeper and with different shapes with no protruding components. This pattern was observed in the group treated by fluoride application followed by Nd:YAG laser irradiation (G3) (Original magnification ×800; Bar =25 μ m) 
Fig. 3 Graphic representation of the demineralization (as a mean percentage of the demineralized area) observed in each of the experimental groups. Bars indicate the standard deviation. Asterisk significantly different from all other groups ( p <0.05) 
Influence of CO2 (10.6 ??m) and Nd:YAG laser irradiation on the prevention of enamel caries around orthodontic brackets

June 2013


175 Reads

One possible undesirable consequence of orthodontic therapy is the development of incipient caries lesions of enamel around brackets. The aim of this study was to compare the effects of CO2 (λ = 10.6 μm) and Nd:YAG (λ = 1,064 nm) lasers associated or not with topical fluoride application on the prevention of caries lesions around brackets. Brackets were bonded to the enamel of 65 premolars. The experimental groups (n = 13) were: G1-application of 1.23 % acidulated fluoride phosphate gel (AFP, control); G2-Nd:YAG laser irradiation (0.6 W, 84.9 J/cm(2), 10 Hz, 110 μs, contact mode); G3-Nd:YAG laser irradiation associated with AFP; G4-CO2 laser irradiation (0.5 W, 28.6 J/cm(2), 50 Hz, 5 μs, and 10 mm focal distance); and G5-CO2 laser irradiation associated with AFP. Quantitative light-induced fluorescence was used to assess enamel demineralization. The data were statistically compared (α = 5 %). The highest demineralization occurred in the Nd:YAG laser group (G2, 26.15 % ± 1.94). The demineralization of all other groups was similar to that of the control group. In conclusion, CO2 laser alone was able to control enamel demineralization around brackets at the same level as that obtained with topical fluoride application.

Protective effect of CO2 laser (10.6 μm) and fluoride on enamel erosion in vitro

February 2012


56 Reads

The aim of this study was to analyze the effect of CO(2) laser (10.6 μm) irradiation with 5-μs pulse width in prevention of enamel erosion due to citric acid exposure in vitro. One hundred forty-four bovine enamel samples were cut into 5 × 5 × 2-mm-size slabs and polished to obtain plane surfaces. Enamel surfaces were covered with acid-resistant varnish, except for a central area of 2.5 mm in diameter. The samples were divided into four groups (n = 12/group/day): C-control, no treatment; L-CO(2) laser irradiation (0.3 J/cm(2), 5 μs, 226 Hz); F-topical fluoride treatment, 1.25%F(-) (AmF/NaF) for 3 min; and FL-fluoride treatment + CO(2) laser. For erosive demineralization, samples were immersed in 40 ml of citric acid (0.05 M, pH 2.3) for 20 min two times per day during 5 days. After 1, 3, and 5 days, surface loss was measured by digital profilometer. According to the repeated measure ANOVA and post hoc comparisons, all the treatments showed statistically significant reduction of enamel loss as compared to control group, in all investigated times (p < 0.0001): L (52%,31%,37%); F (28%,24%,29%); FL (73%,55%,57%). Both CO(2) laser irradiation alone (L) and the combined laser-fluoride treatment (FL) caused less enamel loss than the fluoride group (F) in all days (p < 0.0001 for L in all times; and p < 0.0001, p = 0.0220 and p = 0.0051 for F, respectively, at days 1, 3, and 5). Under the conditions of this study, CO(2) laser irradiation (0.3 J/cm(2), 5 μs, 226 Hz) could effectively reduce enamel surface loss due to citric acid exposure, in vitro. This effect was still observed after 5 days of repeated acid exposures.

Table 1 Laser devices used in the study 
Assessment of the effect of laser irradiations at different wavelengths (660, 810, 980, and 1064 nm) on autophagy in a rat model of mucositis

March 2015


290 Reads

It is known that high-dose radiation has an effect on tissue healing, but tissue healing does not occur when low dose radiation is applied. To clarify this issue, we compare the treatment success of low dose radiation with programmed cell death mechanisms on wounded tissue. In this study, we aimed to investigate the interactions of low and high-dose radiation using an autophagic mechanism. We included 35 adult Wistar-Albino rats in this study. All animals were injected with 100 mg/kg of 5-fluorouracil (5-FU) on the first day and 65 mg/kg of 5-FU on the third day. The tips of 18-gauge needles were used to develop a superficial scratching on the left cheek pouch mucosa by dragging in a linear movement on third and fifth days. After mucositis formation was clinically detected, animals were divided into five groups (n = 7). Different wavelengths of laser irradiations (1064 nm, Fidelis Plus, Fotona, Slovenia; 980 nm, FOX laser, A.R.C., Germany; 810 nm, Fotona XD, Fotona, Slovenia; 660 nm, HELBO, Medizintechnik GmbH, Wels, Austria) were performed on four groups once daily for 4 days. The laser irradiation was not performed on the control group. To get the tissue from the left cheek at the end of fourth day from all animals, oval excisional biopsy was performed. Molecular analysis assessments of pathological and normal tissue taken were performed. For this purpose, the expression analysis of autophagy genes was performed. The results were evaluated by normalization and statistics analysis. We found that Ulk1, Beclin1, and Atg5 expression levels were increased in the rats when the Nd:YAG laser was applied. This increase showed that a 1064-nm laser is needed to activate the autophagic mechanism. However, in the diode applications, we found that Beclin1, Atg10, Atg5, and Atg7 expressions numerically decreased. Atg5 is responsible for the elongation of autophagosome. Becn1 is a control gene in the control mechanism of autophagy. The reduction of the expression of these genes leads us to think that it may depend on the effect of drug (5-FU) used to form model. Expressions of therapeutic genes increase to ensure hemostasis, but in our study, expressions were found to decrease. More detailed studies are needed.

1064 Nd:YAG laser for the treatment of chronic paronychia: a pilot study

December 2013


165 Reads

Paronychia, which can be acute or chronic, is characterized by erythema, edema, and tenderness at the proximal and occasionally lateral nail folds. Causes of chronic paronychia include excessive moisture, contact irritants, trauma, and candida infection. Chronic paronychia is usually multifactorial and difficult to treat. The aim of the present work was to assess the role of neodymium-doped yttrium aluminium garnet (Nd:YAG) laser as a new modality for the treatment of chronic paronychia. In this interventional pilot study, eight female patients suffering from long-standing paronychia received 2-5 Nd:YAG laser sessions (4 weeks apart). Fluences ranged between 70 to 80 J/cm(2), using a 2.5-mm spot size handpiece, and pulse duration was set at 0.7 ms. Patients were digitally photographed and clinically evaluated before starting the treatment and at each session. Seven of our patients showed various degree of improvement regarding erythema and swelling of their proximal nail folds. Nail plate abnormalities also improved in six patients. These preliminary results document the efficacy and feasibility of Nd:YAG laser as one of the treatments that could ameliorate chronic paronychia.

Table 1 The statistical analysis and mean values of the results of this study 
Effects of laser irradiation at different wavelengths (660, 810, 980, and 1064 nm) on transient receptor potential melastatin channels in an animal model of wound healing

April 2015


269 Reads

The aim of the present study was to compare the effectiveness of four different laser wavelengths used for low-level laser therapy(LLLT) on healing of mucositis in an animal model of wound healing, by investigating expression of transient receptor potential melastatin(TRPM) ion channels. Forty-five rats were intraperitoneally injected with 100 mg/kg 5-fluorouracil on day 1 and 65 mg/kg on day 3. Superficial scratching on left cheek pouch mucosa was performed on days 3 and 5. After ulcerative mucositis was clinically detected, LLLT was started (660 nm, HELBO; 810 nm, Fotona-XD; 980 nm, ARC-Fox; and 1064 nm, Fidelis-Plus3) at 8 J/cm(2)/day from days 1 to 4. Oval excisional biopsy was performed at the wound site, and expression of TRPM2 to TRPM8 was evaluated. Student's t test was used for evaluation of significance of TRPM gene expression according to "0" value (α = 0.05). In 980-nm group, TRPM4, TRPM6, and TRPM7 were significantly higher than in the control group (p < 0.005). In 660, 810, and 1064 nm groups, only TRPM6 was significantly higher than in control group (p < 0.005). There were no significant differences between control and sham groups (p > 0.05). These findings suggest that expression of TRPM6 gene was significantly affected by irradiation with lasers at different wavelengths, whereas the TRPM4 and TRPM7 genes were only expressed in the 980-nm diode laser group. TRPM6 gene was highly expressed during LLLT, which may lead to accelerated wound healing and tissue repair. In contrast, there was some evidence that the 980-nm diode laser caused increased expression of TRPM4, TRPM6, and TRPM7 which are responsible for stimulation of Ca(2+) and Mg(2+) metabolism, as well as apoptotic pathways of controlled cell death.

Impact of 120-W 2-μm continuous wave laser vapoenucleation of the prostate on sexual function

July 2013


23 Reads

The objective of this work is to evaluate the impact of 120-W 2-μm continuous wave (cw) laser vapoenucleation of the prostate in patients with benign prostatic hyperplasia (BPH) on sexual function. One hundred twenty-two consecutive patients with BPH were retrospectively collected in this study and were classified into two groups for surgical treatment with 2-μm cw laser vapoenucleation or transurethral resection of the prostate (TURP). International Index of Erectile Function (IIEF) and general assessment questions were completed before and 12 months after treatment to determine the impact on sexual function. A total of 33 patients (52.4 %) in group 1 and 31 (52.5 %) in group 2 reported various degrees of erectile dysfunction before surgery. Interestingly, an increase in IIEF-EF score by 2 points was reported by 16 (25.4 %) and 14 (23.7 %) patients, respectively, and mean EF score did show a marginal but not significant increase postoperatively in both group. Differences about orgasmic intercourse satisfaction, sexual desire domain, and overall satisfaction scores in each group were not significant between preoperative and postoperative, but there was a significant decrease in the orgasmic function domain score at 12 months postoperation in both groups (p < 0.001). The prevalence of postoperative retrograde ejaculation was significantly higher than at baseline assessment in two groups. This study demonstrates that there is no difference between 2 μm laser vapoenucleation and TURP in terms of impact on sexual function. No significant erectile function improvement was observed after surgery, but these two techniques significantly lowered the IIEF orgasmic function domain and this was mainly caused by retrograde ejaculation.

Fig. 1 Experimental setting: laser and fixed handheld over the liver surface 
Fig. 2 Histologic example of liver lesions (marked by the arrows ) with a 60- and 120-W laser output power (working speed 5 mm/s), magnification ×12.5, HE staining 
Fig. 3 Histologic example of liver lesions (marked by the arrows ) with a 60- and 120-W laser output power (laser power output 120 W; working speed 20 mm/s), magnification ×12.5, HE staining 
Fig. 4 Histologic example, demonstrating that the liver septa (marked by the arrows ) may be frontiers for the thermal damage of the liver tissue (working speed 20 mm/s), magnification ×12.5, HE staining 
Fig. 5 Comparison of the 1-min resected liver parenchyma by a 60- and 120-W laser output 
The Nd:YAG LIMAXA (R) 120 high-output laser: local effects and resection capacity on liver parenchyma

February 2014


254 Reads

Various technical options are available for the resection of liver metastases, including CUSA, Ultracision, water-jet, and stapler devices. It has been shown that new generation high-output lasers are suitable for the resection of lung metastases. The goal of the present study was to evaluate the local effects of laser application on liver parenchyma. Livers of freshly slaughtered pigs (N = 6) were analyzed. The handheld laser was vertically held in the clamp of a hydraulic machine and sharply focused on the liver surface. The diode pumped Nd:YAG laser LIMAX® 120 (Gebrüder Martin GmbH & Co. KG, Tuttlingen, Germany) moved evenly over the liver surface at speeds of 5, 10, and 20 mm/s. Laser outputs of 60 and 120 W were applied at every speed. Histological sections (hematoxylin and eosin (HE) staining) of the extension area of vaporization and coagulation were analyzed by the use of the ImageJ software. In addition, the area of the liver parenchyma cut by the laser within 1 min was measured. The vaporized zone appeared wedge-shaped after histological section, whereas the area of coagulation appeared radiated outward. At 10 mm/s and 60 W, the mean vaporization of the measured zone was 356.6 ± 3.9 μm in length. Superficial coagulation was observed at 20 mm/s laser speed, without effective resection. At 120 W and 5 mm/s working speed, the mean vaporization zone and the average width of coagulation were largest with 664.6 ± 5.9 and 375.6 ± 2.3 μm, respectively. The laser output power of 120 W allowed resection of an area of 6 ± 0.4 cm(2) of liver parenchyma within 1 min. The Nd:YAG Laser LIMAX® 120 might be an effective tool for liver parenchyma dissection when it is applied at maximum output (120 W) and at a constant working speed of 5 mm/s.

Efficacy of a vaporization–resection of the prostate median lobe enlargement and vaporization of the prostate lateral lobe for benign prostatic hyperplasia using a 120-W GreenLight high-performance system laser: the effect on storage symptoms

April 2015


82 Reads

GreenLight laser photoselective vaporization of the prostate (PVP) was established as a minimally invasive procedure to treat patients with benign prostatic hyperplasia (BPH). However, it may be difficult to achieve adequate tissue removal from a large prostate, particularly those with an enlarged median lobe. The purpose of this study was to investigate the feasibility and clinical effect of a 120-W GreenLight high-performance system laser vaporization-resection for an enlarged prostate median lobe compared with those of only vaporization. A total of 126 patients from January 2010 to January 2014 had an enlarged prostate median lobe and were included in this study. Ninety-six patients underwent vaporization only (VP group), and 30 patients underwent vaporization-resection for an enlarged median lobe (VR group). The clinical outcomes were International Prostate Symptoms Score (IPSS), quality of life (QOL), maximum flow rate (Q max), and post-void residual urine volume (PVR) assessed at 1, 3, 6, and 12 months postoperatively between the two groups. The parameters were not significantly different preoperatively between the two groups, except for PVR. Operative time and laser time were shorter in the VR group than those in the VP group. (74.1 vs. 61.9 min and 46.7 vs. 37.8 min; P = 0.020 and 0.013, respectively) and used less energy (218.2 vs. 171.8 kJ, P = 0.025). Improved IPSS values, increased Q max, and a reduced PVR were seen in the two groups. In particular, improved storage IPSS values were higher at 1 and 3 months in the VR group than those in the VP group (P = 0.030 and 0.022, respectively). No significant complications were detected in either group. Median lobe tissue vaporization-resection was complete, and good voiding results were achieved. Although changes in urinary symptoms were similar between patients who received the two techniques, shorter operating time and lower energy were superior with the vaporization-resection technique. In addition, vaporization-resection may have a beneficial effect on storage symptoms.

GreenLight HPS 120-W laser photoselective vaporization of the prostate as early therapy for acute urinary retention in advanced prostate cancer patients

January 2013


24 Reads

We evaluate the safety, efficacy, and oncological outcomes of early palliative photoselective vaporization of the prostate (PVP) by GreenLight high-performance system (HPS) 120-W laser in patients with acute urinary retention (AUR) induced by advanced prostate cancer (PCa). A total of 39 advanced PCa patients with AUR who underwent PVP were enrolled in this retrospective study. Baseline parameters, perioperative, and postoperative complications were reviewed. The functional outcomes were evaluated at 1, 3, 6, and 12 months after surgery using the International Prostate Symptom Score (IPSS), quality of life (QoL) score, peak urinary flow rate (Q max), and postvoid residual urine volume (PVR). At baseline, mean age was 72.8 ± 6.8 years and mean prostate-specific antigen (PSA) level was 45.2 ± 26.9 ng/mL. The average energy consumed was 171.2 ± 72.3 kJ during a mean operative time of 46.3 ± 13.7 min. Mean catheterization duration was 3.3 ± 0.8 days. Mean hospitalization time was 5.2 ± 0.5 days. Compared with the preoperative values, there were significant continuous improvement in IPSS, QoL score, Q max, and PVR at all time points of follow-up. The mean PSA nadir was 0.33 ± 0.15 ng/mL and the mean time to PSA nadir was 10.3 ± 2.5 months. Nine patients (23 %) eventually developed hormone refractory prostate cancer. No patient experienced severe intraoperative and postoperative complications. Our preliminary investigation shows that GreenLight HPS 120-W laser PVP is a safe and effective treatment for advanced PCa patients with AUR. Patients may obtain some oncological benefits from tumor cytoreduction by early palliative PVP.

Treatment of 153 Japanese patients with Q-switched alexandrite laser

October 2007


74 Reads

We have recently used Q-switched alexandrite laser for the treatment of various kinds of pigmented skin lesions. We retrospectively compared therapeutic outcomes of 153 Japanese patients who consulted our department. This approach was not very efficient for nevus spilus/café-au-lait spots, which seemed laser-resistant, especially when the pigmentation had appeared after 1 year of age, was treated after 5 years of age, was located on the face, was oval with a smooth border, and the patient was male. This approach was equally effective for senile lentigo, nevus of Ota, and Mongolian spots, but less effective for acquired bilateral nevus of Ota-like macules. Some patients with sacral Mongolian spots or those with light-colored, senile lentigo developed severe post-inflammatory hyperpigmentation after treatment. As a whole, good therapeutic outcome was achieved after multiple treatment sessions. However, the use of other lasers or other treatment modalities should be considered to treat nevus spilus/café-au-lait spots.

Treatment of actinic keratoses and photodamage with non-contact fractional 1540-nm laser quasi-ablation: An ex vivo and clinical evaluation

April 2012


79 Reads

The main use of non-ablative fractional photothermolysis today is for the improvement of wrinkles and scars. The purpose of this work was to evaluate the effect of a "classic" non-ablative fractional 1540nm on facial photodamaged skin and actinic keratoses. Seventeen patients with facial actinic keratoses (AKs) and photodamage underwent two or three laser treatments with fractional 1540-nm erbium glass laser at fluences of 75 mJ, 15 ms pulse duration, and 10-mm spot size in non-contact mode. Two blinded assessors and participants evaluated clinical improvement of treatment areas after 3 months, using a quartile grading scale (no improvement = 0, 1-25% improvement = 1, 26-50% = 2, 51-75% = 3, and 76-100% = 4). Three months after the last treatment, the mean level of improvement was 3.4 ± 0.72 for AK and 3.3 ± 0.54 for skin appearance. Adverse events observed after each treatment were moderate erythema, mild edema, erosions (two cases), and mild desquamation. No scarring or post-inflammatory pigmentary changes were observed. The clinical results were supported by histological changes observed in Yucatan pig studies in vivo and ex vivo. The 1540-nm fractional erbium glass laser in the non-contact mode is a safe and effective treatment for facial photodamage and AKs.

Immunocytochemical studies on the effect of 405-nm low-power laser irradiation on human-derived A-172 glioblastoma cells

October 2011


57 Reads

The application of low-power laser irradiation (LLI) affects the cell cycle and cell proliferation in various kinds of cells. LLI at a wavelength of 808 nm and a power of 30 mW has been found to significantly decrease the proliferation rate of cells of the human-derived glioblastoma cell line A-172. To determine if this effect of LLI is specific to 808-nm LLI, the present study was designed to reveal the effects of 405-nm LLI under the same experimental conditions. A-172 glioblastoma cells were cultured in 96-well plates according to the conventional protocol. Two different schedules of 405-nm LLI (27 mW) were tested: longer periods of 20, 40 and 60 min and shorter periods of 1, 2, 3, 5, 10 and 15 min. Cells on a digital image displayed on a computer monitor were counted and the proliferation ratio was determined using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) staining. Annexin-V-FLUOS staining and acridine-orange/ethidium-bromide staining were in an immunocytochemical assay to determine if cells were viable or dead (due to apoptosis or necrosis). Cell counting and MTT staining showed that longer 405-nm LLI significantly suppressed the proliferation of A-172 cells at 48 h after LLI (p < 0.05 or p < 0.01) and that the effect of LLI tended to be dose-dependent with morphological changes including cell death. At 90 min after LLI, shorter 405-nm LLI caused necrotic as well as apoptotic cell death, and these effects depended on irradiation time, power and energy density. Detailed analysis revealed that this lethal effect occurred after LLI and was not sustainable. It is concluded that 405-nm LLI has a lethal effect on human-derived glioblastoma A-172 cells, that is different from the suppressive effect without morphological changes induced by 808-nm LLI.

The 532-nm 180-W (GreenLight®) laser vaporization of the prostate for the treatment of lower urinary tract symptoms: How durable is the new side-fire fiber with integrated cooling system?

April 2013


40 Reads

The 532-nm side-fire laser vaporization is established for the treatment of symptomatic benign prostate hyperplasia. Meanwhile, the third generation of this system is offered by American Medical Systems, Inc. The laser power increased from 80 and 120 to 180 W from the first to the third generation. Despite good functional results, with the 80- and 120-W systems, the removal of prostate tissue is limited because of fiber degradation. To overcome this problem, the fiber was designed newly with an integrated cooling system and a sensor for decreasing the laser energy in case of overheating. We evaluate whether the new fiber still suffers from degradation with consecutive drop of power transmission during the procedure. The power output of the cooled fiber was measured in vitro and during prostate vaporization in ten patients. Laser beam power was measured at baseline and after the application each of 50 kJ during laser vaporization. Power emission of the fiber remains constant at 20, 80, and 180 W of power settings over the whole 40-kJ lifespan. During the transurethral procedure, a median total energy of 276 kJ (standard deviation 153 kJ) was applied for vaporization. Median power output from the fiber at the end of the procedure was 97 % from the baseline value. There were no fiber malfunctions observed. In contrast to former generations, the third-generation laser fiber is durable without significant power loss during prostate vaporization.

Fig. 1 Principles of the LAMA technique: stay sutures are performed to remove the tension and a 1950-nm laser tissue welding technique complete the anastomosis 
Table 1 Patient demographics in our series
Fig. 2 The 1950-nm diode laser used for the current LAMA study 
Table 2 Laser parameters and outcomes for each LAMA procedure
Fig. 3 Hemi hand amputation before ( a ) and directly after replantation ( b ) with the LAMA technique 
1950-nm diode laser-assisted microanastomoses (LAMA): an innovative surgical tool for hand surgery emergencies

February 2015


1,368 Reads

Based on previous observations, the 1950-nm diode laser seems to be an ideal wavelength for laser microvascular anastomoses. The data presented here, part of a larger ongoing study, assess its use in emergency hand surgery. Between 2011 and 2014, 11 patients were operated on for hand trauma with laser-assisted microanastomoses (LAMA) and prospectively analysed. LAMA was performed with a 1950-nm diode laser after placement of equidistant stitches. For vessel size <1.5 mm, the following laser parameters were used: spot size 400 μm, five spots for each wall, power 125 mW, and arterial/venous fluence 100/90 J/cm(2) (spot duration 1/0.9 s). Mean operating time for arterial and venous microanastomoses was 7.3 ± 1.4 and 8.7 ± 1.0 min, respectively. Three anastomoses required a secondary laser application. Arterial and venous patency rates were 100 % at the time of surgery. The success rate for the 11 procedures assessed clinically and with the Doppler was 100 %. The technique is compared to the current literature. The 1950-nm LAMA is a reliable tool with excellent results in emergency hand surgery. The system is very compact and transportable for utilization in the emergency operating room.

Hedelund L, Lerche C, Wulf HC, Haedersdal MCarcinogenesis related to intense pulsed light and UV exposure: an experimental animal study. Lasers Med Sci 21: 198-201

December 2006


102 Reads

This study examines whether intense pulsed light (IPL) treatment has a carcinogenic potential itself or may influence ultraviolet (UV)-induced carcinogenesis. Secondly, it evaluates whether UV exposure may influence IPL-induced side effects. Hairless, lightly pigmented mice (n=144) received three IPL treatments at 2-week intervals. Simulated solar radiation was administered preoperatively [six standard erythema doses (SED) four times weekly for 11 weeks] as well as pre- and postoperatively (six SED four times weekly up to 26 weeks). Skin tumors were assessed weekly during a 12-month observation period. Side effects were evaluated clinically. No tumors appeared in untreated control mice or in just IPL-treated mice. Skin tumors developed in UV-exposed mice independently of IPL treatments. The time it took for 50% of the mice to first develop skin tumor ranged from 47 to 49 weeks in preoperative UV-exposed mice (p=0.94) and from 22 to 23 weeks in pre- and postoperative UV-exposed mice (p=0.11). IPL rejuvenation of lightly pigmented skin did not induce pigmentary changes (p=1.00). IPL rejuvenation of UV-pigmented skin resulted in an immediate increased skin pigmentation and a subsequent short-term reduced skin pigmentation (p<0.002). Postoperative UV radiation resulted in re-pigmentation of IPL-induced pigment reduction (p=0.12). No texture changes were observed. Postoperative edema and erythema were increased by preoperative UV exposure (p<0.002). IPL rejuvenation has no carcinogenic potential itself and does not influence UV-induced carcinogenesis. UV exposure influences the occurrence of side effects after IPL rejuvenation in an animal model.

Effects of low-level He-Ne laser irradiation on the gene expression of IL-1beta, TNF-alpha, IFN-gamma, TGF-beta, bFGF, and PDGF in rat's gingiva

July 2008


86 Reads

Biostimulatory effects of laser irradiation on cell proliferation and wound healing has been reported. However, little is known about the molecular basis of the mechanism. Interleukin 1β (IL-1β), tumor necrotic factor-α (TNF-α), and interferon-γ (IFN-γ) play an important role in inflammation, while platelet-derived growth factor (PDGF), transforming growth factor-β (TGF-β) and blood-derived fibroblast growth factor (bFGF) are the most important growth factors of periodontal tissues. The aim of this study was to investigate the effect of low-level He-Ne laser on the gene expression of these mediators in rats' gingiva and mucosal tissues. Twenty male Wistar rats were randomly assigned into four groups (A 24, A48, B24, B48) in which A 24 and A48 were cases and B24, B48 were controls. An incision was made on gingiva and mucosa of the labial surface of the rats' mandibular incisors. Group A24 was irradiated twice with 24 hours interval, while the inflamed tissues of group A48 was irradiated three times with continuous He-Ne laser (632.8 nm) at a dose of 7.5 J/cm2 for 300 s. An energy of 5.1 J was given to the 68 mm2 irradiation zone. Rats were killed 30 min after the last irradiation of case and control groups, then excisional biopsy was performed. Gene expression of the cytokines was measured using reverse transcriptase-polymerase chain reaction (RT-PCR) technique. Results were analyzed with Kruskal-Wallis and Mann-Whitney U tests. The gene expression of IL-1β and IFN-γ was significantly inhibited in the test groups (P<0.05), while the gene expression of PDGF and TGF-β were significantly increased (P<0.05). The case and control groups did not have a significant difference in the gene expression of TNF-α and bFGF (P>0.05). These findings suggest that low-level He-Ne laser irradiation decreases the amount of inflammation and accelerates the wound healing process by changing the expression of genes responsible for the production of inflammatory cytokines.

Anti-inflammatory effect of linear polarized infrared irradiation on interleukin-1β-induced chemokine production in MH7A rheumatoid synovial cells

January 2006


21 Reads

We examined the anti-inflammatory effect of infrared linear polarized light irradiation on the MH7A rheumatoid fibroblast-like synoviocytes (FLS) stimulated with the proinflammatory cytokine interleukin (IL)-1beta. Expression of messenger ribonucleic acids (mRNAs) encoding IL-8, RANTES (regulated upon activation, normal T cell expressed and secreted), growth-related gene alpha (GROalpha), and macrophage inflammatory protein-1alpha (MIP1alpha) was measured using real-time reverse transcription polymerase chain reaction, and the secreted proteins were measured in the conditioned media using enzyme-linked immunosorbent assays. We found that irradiation with linear polarized infrared light suppressed IL-1beta-induced expression of IL-8 mRNA and, correspondingly, the synthesis and release of IL-8 protein in MH7A cells. This anti-inflammatory effect was equivalent to that obtained with the glucocorticoid dexamethasone. Likewise, irradiation suppressed the IL-1beta-induced expression of RANTES and GROalpha mRNA. These results suggest that the irradiation of the areas around the articular surfaces of joints affected by rheumatoid arthritis (RA) using linear polarized light may represent a useful new approach to treatment.

Effect of photobiomodulation on expression of IL-1β in skeletal muscle following acute injury

November 2012


34 Reads

Muscle repair is regulated by growth factors and cytokines. Low-level laser therapy (LLLT) seems to influence acute inflammation and accelerate skeletal muscle repair. This study verifies the effect of LLLT on the expression of IL-1β in the tibialis anterior (TA) muscle of rats following acute injury. Wistar rats (n = 35) were allocated into three groups: control (without lesion and LLLT, n = 5), injury group (n = 15), and injury + LLLT group (n = 15). The acute injury was induced by the contact with a cooled metal probe (3 mm in diameter) during 10 s, twice, in the same muscle area. LLLT was used three times a week using the InGaAlP laser (660 nm; beam spot of 0.04 cm(2), output power of 20 mW, power density of 500 mW/cm(2), and energy density of 5 J/cm(2) during 10 s). The animals were analyzed at 1, 7, and 14 days following injury. TA muscles samples were used for obtaining total RNA and performing cDNA synthesis. Real-time polymerase chain reactions were realized using IL-1β primer. There was a decrease in IL-1β expression after 7 days in LLLT group in comparison with the no treated group. In conclusion, LLLT was able to decrease IL-1β expression during the skeletal muscle repair following an acute injury.

Dosedependent photodynamic effects of 9-acetoxy-2,7,12,17-tetrakis(\-methoxyethyl)-porphycene in vitro

December 1997


15 Reads

Porphycenes are chemically pure photosensitizers for topical and systemic photodynamic therapy (PDT). Fast cellular uptake of 9-acetoxy-2,7,12,17-tetrakis-(sB-methoxyethyl)porphycene (ATMPn) has been shown previously. HaCaT human keratinocytes were incubated with ATMPn (1 nmol l-1 to 1 µmol l-1 in DMSO or DOPC liposomes). After 1 h, cells were irradiated with different light doses (0, 24, 48J cm-2) using an incoherent light source (580—740 nm, 40 mW cm-2). Cytotoxic effects were determined by assessing the mitochondrial activity using the MTT assay 24 h following irradiation. Cytotoxic effects were dependent on ATMPn concentration and light dose. Using 20 nmol 1-1, a 50% decrease of mitochondrial activity (EC50) after irradiation with 24 J cm-2 was achieved. Lowering the ATMPn concentration (10nmol 1-1) and increasing the light dose (48 J cm-2) yielded the same effect (EC50). Maximal decrease of mitochondrial activity (90%) was achieved using ATMPn concentrations of 50–100 nmol l-1 and a light dose of 24 J cm-2 or 25 nmol l-1 ATMPn and 48 Jcm-2. There was no difference regarding the dose-dependent cytotoxic effects using either ATMPn in DMSO or DOPC liposomes. In the control group (incubation with 1 nmol 1-1 to 1µmol 1-1 ATMPn, no irradiation), dark toxicity was not observed. Cell photosensitization with ATMPn was very efficient in vitro yielding the maximal cytotoxic effect at very low ATMPn concentrations as compared to other photosensitizers. Since ATMPn in DMSO and DOPC liposomes revealed the same cytotoxic effects without dark toxicity, theDMSO formulation, which is much easier to prepare, will be preferred in future studies.

Er:YAG 2,940-nm laser fiber in endodontic treatment: A help in removing smear layer

December 2012


94 Reads

Cleaning and disinfection of the root canal system are some of the most important goals in endodontic therapy. The aim of this preliminary study is to assess the effectiveness of Er:YAG laser fiber in removing the smear layer produced during root canal walls instrumentation. Forty-eight single-rooted teeth were prepared with manual and rotary Ni-Ti instruments, in addition to 2.5 % NaOCl irrigation. Samples were randomly subdivided into groups and treated with: three irradiations of 5 s each, with 300-μm Er:YAG endodontic fiber, 1 W and 2.5 % NaOCl solution (A Group); two laser irradiations with 17 % EDTA solution and 2.5 % NaOCl solution (B Group); laser irradiation plus 17 % EDTA solution and 2.5 % NaOCl (C Group); only in the final wash of 17 % EDTA (control group D). During laser treatment, temperature variations were analyzed by using thermocouple and thermal camera devices in order to test both deep and superficial temperatures. Each sample was finally observed by scanning electron microscope (SEM) at the coronal, medium, and apical thirds at ×500 magnification and blindly scored depending on the amount of smear layer. Statistical analysis of the results was conducted using the Kruskal–Wallis and Mann–Whitney test to determine the eventual significant differences between the quantity of smear layer in each group and between the groups at coronal, medium, and apical third: a p value EDTA 17 % and NaOCl 2.5 % has been demonstrated to be effective in removing smear layer, even in the apical third which is described as the hardest area to clean during endodontic treatment.

Transmission of Q-switched erbium:YSGG (?=2.79�?m) and erbium:YAG (?=2.94�?m) laser radiation through germanium oxide and sapphire optical fibres at high pulse energies

February 2004


38 Reads

The erbium:YSGG and erbium:YAG lasers are used for tissue ablation in dermatology, dentistry and ophthalmology. The purpose of this study was to compare germanium oxide and sapphire optical fibres for transmission of sufficient Q-switched erbium laser pulse energies for potential use in both soft and hard tissue ablation applications. Fibre transmission studies were conducted with Q-switched (500 ns) Er:YSGG (lambda=2.79 microm) and Er:YAG (lambda=2.94 microm) laser pulses delivered at 3 Hz through 1-m-long, 450-mum germanium oxide and 425-mum sapphire optical fibres. Transmission of free-running (300 micros) Er:YSGG and Er:YAG laser pulses was also conducted for comparison. Each set of measurements was carried out on seven different sapphire or germanium fibres, and the data were then averaged. Fibre attenuation of Q-switched Er:YSGG laser energy measured 1.3+/-0.1 dB/m and 1.0+/-0.2 dB/m for the germanium and sapphire fibres, respectively. Attenuation of Q-switched Er:YAG laser energy measured 0.9+/-0.3 dB/m and 0.6+/-0.2 dB/m, respectively. A maximum Q-switched Er:YSGG pulse energy of 42 mJ (26-30 J/cm(2)) was transmitted through the fibres. However, fibre tip damage was observed at energies exceeding 25 mJ (n=2). Both germanium oxide and sapphire optical fibres transmitted sufficient Q-switched Er:YSGG and Er:YAG laser radiation for use in both soft and hard tissue ablation. This is the first report of germanium and sapphire fibre optic transmission of Q-switched erbium laser energies of 25-42 mJ per pulse.

Table 1 Implant distribution by length and diameter (mm)
Prospective clinical evaluation of 201 direct laser metal forming implants: Results from a 1-year multicenter study

April 2011


373 Reads

This prospective clinical study evaluated the survival rate and the implant-crown success of 201 direct laser metal forming (DLMF) implants in different clinical applications, after short-term follow-up of functional loading. At the 1-year scheduled follow-up examination, several clinical, radiographic, and prosthetic parameters were assessed. Success criteria included absence of pain, sensitivity, suppuration, exudation; absence of implant mobility; absence of continuous peri-implant radiolucency, DIB <1.5 mm; absence of prosthetic complications at the implant-abutment interface. A total of 201 implants (106 maxilla, 95 mandible) were inserted in 62 patients (39 males, 23 females; aged between 26 and 65 years) in eight different clinical centers. The sites included anterior (n = 79) and posterior (n = 122) implants. The overall implant survival rate was 99.5%, with one implant loss (maxilla: 99.0%, 1 implant failure; mandible: 100.0%, no implant failures). The mean DIB was 0.4 ± 0.2 mm. Among the survived implants (200), five did not fulfill the success criteria, giving an implant-crown success of 97.5%. This 1-year follow-up prospective clinical study gives evidence of very high survival (99.5%) and success (97.5%) rates using DLMF implants.

Mackenzie GD, Jamieson NF, Novelli MR, Mosse CA, Clark BR, Thorpe SM, Bown SG, Lovat LBHow light dosimetry influences the efficacy of photodynamic therapy with 5-aminolaevulinic acid for ablation of high-grade dysplasia in Barrett's esophagus. Lasers Med Sci 23: 203-210

April 2008


25 Reads

Photodynamic therapy (PDT) with 5-aminolaevulinic acid (ALA) is a novel treatment for high-grade dysplasia (HGD) in Barrett's esophagus (BE). Our aim was to evaluate the effectiveness of differing light doses. Patients with HGD in BE received oral ALA (60 mg/kg) activated by low (500 J/cm), medium (750 J/cm), high (1,000 J/cm), or highest (1,000 J/cm x2) light dose at 635 nm. Follow-up was by regular endoscopy with quadrantic biopsies. Twenty-four patients were treated. Successful eradication of HGD was significantly correlated with light dose (log rank, p < 0.01). Six of eight patients (75%) treated with the highest light dose, one of two treated with high dose (50%), two of nine (22%) receiving medium light dose, and zero of five receiving low light dose had successful eradication of HGD (median follow-up 45 months, range 1-78 months). No skin photosensitivity or esophageal strictures occurred. The efficacy of ALA-PDT for eradication of HGD in BE is closely related to the light dose used. With a drug dose of 60 mg/kg and light at 635 nm, we recommend a minimum light dose of 1,000 J/cm of esophagus. This dose appears safe.

Preliminary results of development of a single-mode Q-switched Nd: YAG ring laser at 213�nm and its application for the microsurgical dissection of retinal tissue ex vivo

February 2005


323 Reads

The Nd: YAG laser family offers wide possibilities for surgery applications in medicine. The radiation at 213 nm provides similar tissue effects as compared to 193 nm excimer lasers, but offers considerable practical advantages in the operating room. As such, it is of considerable interest to create single-mode Q-switched fifth harmonic Nd: YAG pulsed lasers with a high coefficient of efficiency and low divergence. Parameters of the ring three-mirror anisotropic cavity TEM00-Nd: YAG laser were calculated on the basis of the analysis of Gaussian beam behavior in the three-mirror ring cavity, with one convex spherical mirror and one intracavity positive lens. On the hand of numerical calculations a prototype of a single-mode Q-switched Nd: YAG-213 nm laser with an output energy of 4 mJ and a beam divergence of 1 mrad has been developed. At a pulse repetition rate of 50 Hz, it has a generation efficiency in the Q-switched mode of 0,6%. A hollow core wave guide is used in combination with a short length of a special fused silica optical fiber to guide the laser beam. Full-depth dissection of rabbit retina ex vivo was achieved at the intensities of 0.18-0.05 J/cm2 and a repetition rate of 50 Hz, with a linear cutting rate of 6 mm/s. Although the retina was completely cut, heat necrosis of the choroid did not occur. We are currently in the process of testing the dissection of retinal tissue during retinotomy, and the formation of holes in the trabecular meshwork in glaucoma surgery.

Fig. 1 Chemical structure of PDZ 
Fig. 2 Photodithazine absorption spectrum. Chlorines present absorption bands in the red and near-infrared regions allowing better tissue light penetration, thus making this photosensitizer an interesting candidate for photodynamic therapy of cancer 
Fig. 3 Differential expression of six genes resulting from comparing the group with therapy after 48 h (G3) with the untreated control group (G2) 
Fig. 4 Differential expression of 16 genes resulting from comparing the group with therapy after 24 h (G4) with the untreated control group (G2) 
Fig. 5 Cluster analysis using genes CIDEA and BAK1 , with significant differences in all groups 
Abstract 250: Apoptosis-associated genes related to photodynamic therapy in breast carcinomas

February 2014


252 Reads

The aim of this study was to find the apoptosis molecular markers involved in the cell death that might be related to photodynamic therapy (PDT) mechanisms in breast cancer. The mammary tumors were induced in 25 Sprague-Dawley female rats by a single, oral gavage of 7,12-dimethylbenz(a)anthracene (DMBA; 70 mg/kg body weight). Animals were divided into four groups: G1 (normal, without DMBA), G2 (control, without PDT treatment), G3 (euthanized 48 h after PDT), and G4 (euthanized 24 h after PDT). For PDT experiments, the photosensitizer used was Photodithazine, and 100 J/cm of light at a fluence rate of 100 mW/cm was delivered to treat lesions. A sample of each animal was investigated by quantitative real-time PCR using Rat Apoptosis RT2 Profiler™ PCR Array platform. The results showed 20 genes with differential expression between PDT and control groups. A significant upregulation was observed for pro-apoptotic genes CASP4, CASP12, CIDEA, GADD45A, and FAS and downregulation of anti-apoptotic genes MAPK8IP1, TNFRSF11B, and NAIP2 in PDT-treated tumors. These results indicate that these genes are more directly involved in cell apoptosis induced by PDT.

Investigations of radicular dentin permeability and ultrastructural changes after irradiation with Er,Cr:YSGG laser and dual wavelength (2780 and 940 nm) laser

May 2015


88 Reads

The aim of this study was to assess the effectiveness of dual wavelength (2780 nm Er,Cr:YSGG, 940 nm diode) laser in elimination of smear layer comparing it with Er,Cr:YSGG laser in terms of radicular dentin permeability and ultrastructural changes of root canal walls. Fifty-one sound single-rooted extracted teeth were instrumented up to size F4 and divided into three groups: group Co, non-irradiated samples; group A, irradiated with Er,Cr:YSGG laser; group B, irradiated with the dual wavelength laser. Afterward, the roots were made externally impermeable, filled with 2 % methylene blue dye, divided horizontally into three segments reflecting the cervical, middle, and apical thirds then examined under microscope. Using analytical software, the root section area and dye penetration area were measured, and then, the percentage of net dye penetration area was calculated. Additionally, scanning electron microscope investigations were accomplished. Analysis of variance (ANOVA) showed significant differences between all groups over the three root thirds. Dye permeation in dual wavelength laser group was significantly higher over the whole root length: cervical, middle, and apical compared to Er,Cr:YSGG laser group and non-irradiated samples (p < 0.001). Scanning electron micrographs of dual wavelength irradiated samples showed a distinctive removal of smear layer with preservation of the annular structure of dentinal tubules. Er,Cr:YSGG laser root canal irradiation produced uneven removal of smear layer, in efficient cleanliness especially in the apical third. There was no sign of melting and carbonization. Within the studied parameters, root canal irradiation with dual wavelength laser increased dentin permeability.

Laser-assisted lipolysis in the treatment of gynecomastia: A prospective study in 28 patients

February 2012


729 Reads

Gynecomastia is the most common breast pathology. Numerous excisions and liposuction techniques have been described to correct bilateral male breast enlargement. Recently, there has been a shift from the open approach to minimally invasive techniques. This article reports a 5-year experience using laser-assisted lipolysis (LAL) to treat gynecomastia, and describes the surgical technique. Between January 2006 and December 2010, a total of 28 patients with bilateral gynecomastia were treated with LAL. Patients had a mean age of 36.5 years (range 24 to 56 years). LAL was performed with a 980-nm diode laser (continuous emission, 15 W power, 8-12 kJ total energy per breast) after tumescent anesthetic infiltration. The breast was evaluated objectively by two physicians who compared chest circumference and photographs. Patients were also asked to score the results using a visual analogue scale: 75 to 100 (very good), 50-74 (good), 25 to 49 (fair) and 0 to 24 (poor). The postoperative period for all patients was incident-free. After 6 months, 18 patients (64.3%) scored the results as "very good", 6 as "good" (21.4%), 3 as "fair" (10.7%) and 1 "poor" (3.6%). Mean chest circumferences pre- and postoperatively were, respectively, 117.4 ± 11.1 cm and 103.3 ± 7.5 cm (p < 0.001), corresponding to a mean difference of 14.1 cm. Physicians scored the photographs as "very good" in 22 patients (78.6%), as "good" in five patients (17.9%), and as "fair" in one patient (3.6%). LAL in gynecomastia is safe and produces significant effects on fatty tissue, with a reduction in breast volume, together with significant skin tightening. Provided an appropriate amount of energy is delivered by an experienced operator, the results are both significant and consistent.

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