945 resultados para low intensity laser


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NSAIDs are widely prescribed and used over the years to treat tendon injuries despite its well-known long-term side effects. In the last years several animal and human trials have shown that low-level laser therapy (LLLT) presents modulatory effects on inflammatory markers, however the mechanisms involved are not fully understood. The aim of this study was to evaluate the short-term effects of LLLT or sodium diclofenac treatments on biochemical markers and biomechanical properties of inflamed Achilles tendons. Wistar rats Achilles tendons (n?=?6/group) were injected with saline (control) or collagenase at peritendinous area of Achilles tendons. After 1?h animals were treated with two different doses of LLLT (810?nm, 1 and 3?J) at the sites of the injections, or with intramuscular sodium diclofenac. Regarding biochemical analyses, LLLT significantly decreased (p?<?0.05) COX-2, TNF-a, MMP-3, MMP-9, and MMP-13 gene expression, as well as prostaglandin E2 (PGE2) production when compared to collagenase group. Interestingly, diclofenac treatment only decreased PGE2 levels. Biomechanical properties were preserved in the laser-treated groups when compared to collagenase and diclofenac groups. We conclude that LLLT was able to reduce tendon inflammation and to preserve tendon resistance and elasticity. (c) 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:19451951, 2012

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In animal and clinical trials low-level laser therapy (LLLT) using red, infrared and mixed wavelengths has been shown to delay the development of skeletal muscle fatigue. However, the parameters employed in these studies do not allow a conclusion as to which wavelength range is better in delaying the development of skeletal muscle fatigue. With this perspective in mind, we compared the effects of red and infrared LLLT on skeletal muscle fatigue. A randomized double-blind placebo-controlled crossover trial was performed in ten healthy male volunteers. They were treated with active red LLLT, active infrared LLLT (660 or 830 nm, 50 mW, 17.85 W/cm(2), 100 s irradiation per point, 5 J, 1,785 J/cm(2) at each point irradiated, total 20 J irradiated per muscle) or an identical placebo LLLT at four points of the biceps brachii muscle for 3 min before exercise (voluntary isometric elbow flexion for 60 s). The mean peak force was significantly greater (p < 0.05) following red (12.14%) and infrared LLLT (14.49%) than following placebo LLLT, and the mean average force was also significantly greater (p < 0.05) following red (13.09%) and infrared LLLT (13.24%) than following placebo LLLT. There were no significant differences in mean average force or mean peak force between red and infrared LLLT. We conclude that both red than infrared LLLT are effective in delaying the development skeletal muscle fatigue and in enhancement of skeletal muscle performance. Further studies are needed to identify the specific mechanisms through which each wavelength acts.

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Arthritis of the knee is the most common type of joint inflammatory disorder and it is associated with pain and inflammation of the joint capsule. Few studies address the effects of the 810-nm laser in such conditions. Here we investigated the effects of low-level laser therapy (LLLT; infrared, 810-nm) in experimentally induced rat knee inflammation. Thirty male Wistar rats (230-250 g) were anesthetized and injected with carrageenan by an intra-articular route. After 6 and 12 h, all animals were killed by CO(2) inhalation and the articular cavity was washed for cellular and biochemical analysis. Articular tissue was carefully removed for real-time PCR analysis in order to evaluate COX-1 and COX-2 expression. LLLT was able to significantly inhibit the total number of leukocytes, as well as the myeloperoxidase activity with 1, 3, and 6 J (Joules) of energy. This result was corroborated by cell counting showing the reduction of polymorphonuclear cells at the inflammatory site. Vascular extravasation was significantly inhibited at the higher dose of energy of 10 J. Both COX-1 and 2 gene expression were significantly enhanced by laser irradiation while PGE(2) production was inhibited. Low-level laser therapy operating at 810 nm markedly reduced inflammatory signs of inflammation but increased COX-1 and 2 gene expression. Further studies are necessary to investigate the possible production of antiinflammatory mediators by COX enzymes induced by laser irradiation in knee inflammation.

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Objective: to evaluate the effects of low-level laser therapy for perineal pain and healing after episiotomy. Design: a double-blind, randomised, controlled clinical trial comparing perineal pain scores and episiotomy healing in women treated with low-level laser therapy (LLLT) and with the simulation of the treatment. Setting: the study was conducted in the Birth Centre and rooming-in units of Amparo Maternal, a maternity service located in the city of Sao Paulo, Brazil. Participants: fifty-two postpartum women who had had mediolateral episiotomies during their first normal delivery were randomly divided into two groups of 26: an experimental group and a control group. Intervention: in the experimental group, the women were treated with LLLT. Irradiation was applied at three points directly on the episiotomy after the suture and in three postpartum sessions: up to 2 hrs postpartum, between 20 and 24 hrs postpartum and between 40 and 48 hrs postpartum. The LLLT was performed with diode laser, with a wavelength of 660 nm (red light), spot size of 0.04 cm(2), energy density of 3.8 J/cm(2), radiant power of 15 mW and 10 s per point, which resulted in an energy of 0.15 J per point and a total energy of 0.45 J per session. The control group participants also underwent three treatment sessions, but without the emission of radiation (simulation group), to assess the possible effects of placebo treatment. Main outcomes: perineal pain scores, rated on a scale from 0 to 10, were evaluated before and immediately after the irradiation in the three sessions. The healing process was assessed using the REEDA scale (Redness, Edema, Echymosis, Discharge Aproximation) before each laser therapy session and 15 and 20 days after the women's discharge. Findings: comparing the pain scores before and after the LLLT sessions, the experimental group presented a significant within-group reduction in mean pain scores after the second and third sessions (p=0.003 and p<0.001, respectively), and the control group showed a significant reduction after the first treatment simulation (p=0.043). However, the comparison of the perineal pain scores between the experimental and control groups indicated no statistical difference at any of the evaluated time points. There was no significant difference in perineal healing scores between the groups. All postpartum women approved of the low-level laser therapy. Conclusions: this pilot study showed that LLLT did not accelerate episiotomy healing. Although there was a reduction in perineal pain mean scores in the experimental group, we cannot conclude that the laser relieved perineal pain. This study led to the suggestion of a new research proposal involving another irradiation protocol to evaluate LLLT's effect on perineal pain relief. (C) 2011 Elsevier Ltd. All rights reserved.

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Little is known about the benefits of low-level laser therapy (LLLT) on improvement of stability of dental implants. The aim of this randomized clinical study was to assess the LLLT effect on implants stability by means of resonance frequency analysis (RFA). Thirty implants were distributed bilaterally in the posterior mandible of eight patients. At the experimental side, the implants were submitted to LLLT (830 nm, 86 mW, 92.1 J/cm(2), 0.25 J, 3 s/point, at 20 points), and on the control side, the irradiation was simulated (placebo). The first irradiation was performed in the immediate postoperative period, and it was repeated every 48 h in the first 14 days. The initial implant stability quotient (ISQ) of the implants was measured by means of RFA. New ISQ measurements were made after 10 days, 3, 6, 9, and 12 weeks. The initial ISQ values ranged from 65-84, with a mean of 76, undergoing a significant drop in stability from the 10th day to the 6th week in the irradiated group, and presenting a gradual increase from the 6th to the 12th week. The highest ISQ values were observed on the 10th day in the irradiated group, and the lowest in the 6th week in both groups. Under the conditions of this study, no evidence was found of any effect of LLLT on the stability of the implants when measured by RFA. Since high primary stability and good bone quality are of major relevancy for a rigid bone-implant interface, additional LLLT may have little impact macroscopically.

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Background: Carpal tunnel syndrome is the most common neuropathy in the upper extremity, resulting from the compression of the median nerve at wrist level. Clinical studies are essentials to present evidence on therapeutic resources use at early restoration on peripheral nerve functionality. Low-level laser therapy has been widely investigated in researches related to nerve regeneration. Therefore, it is suggested that the effect of low-level laser therapy associated with other conservative rehabilitation techniques may positively affect symptoms and overall hand function in compressive neuropathies such as carpal tunnel syndrome. The aim of this study is to evaluate the effectiveness of low-level laser therapy in addition to orthoses therapy and home orientations in patients with carpal tunnel syndrome. Methods/Design: Patients older than 18 years old will be included, with clinical diagnosis of carpal tunnel syndrome, excluding comorbidies. A physiotherapist will conduct intervention, with a blinding evaluator. Randomization will be applied to allocate the patients in each group: with association or not to low-level laser therapy. All of them will be submitted to orthoses therapy and home orientations. Outcome will be assessed through: pain visual analogic scale, Semmes Weinstein monofilaments (TM) threshold sensibility test, Pinch Gauge T, Boston Carpal Tunnel Questionnaire and two point discrimination test. Discussion: This paper describes the design of a randomized controlled trial, which aim to assess the effectiveness of conservative treatment added to low-level laser therapy for patients with carpal tunnel syndrome. Trial registration: Brazilian Clinical Trials Registry (ReBec) - 75ddtf / Universal Trial Number: U1111-1121-5184

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The aim of this controlled animal study was to investigate the effect of low-level laser therapy (LLLT) administered 30 min after injury to the Achilles tendon. The study animals comprised 16 Sprague Dawley male rats divided in two groups. The right Achilles tendons were injured by blunt trauma using a mini guillotine, and were treated with LLLT or placebo LLLT 30 min later. The injury and LLLT procedures were then repeated 15 hours later on the same tendon. One group received active LLLT (lambda = 904 nm, 60 mW mean output power, 0.158 W/cm(2) for 50 s, energy 3 J) and the other group received placebo LLLT 23 hours after LLLT. Ultrasonographic images were taken to measure the thickness of the right and left Achilles tendons. Animals were then killed, and all Achilles tendons were tested for ultimate tensile strength (UTS). All analyses were performed by blinded observers. There was a significant increase in tendon thickness in the active LLLT group when compared with the placebo group (p < 0.05) and there were no significant differences between the placebo and uninjured left tendons. There were no significant differences in UTS between laser-treated, placebo-treated and uninjured tendons. Laser irradiation of the Achilles tendon at 0.158 W/cm(2) for 50 s (3 J) administered within the first 30 min after blunt trauma, and repeated after 15 h, appears to lead to edema of the tendon measured 23 hours after LLLT. The guillotine blunt trauma model seems suitable for inflicting tendon injury and measuring the effects of treatment on edema by ultrasonography and UTS. More studies are needed to further refine this model.

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Low-level laser irradiation (LLLI) and recombinant human bone morphogenetic protein type 2 (rhBMP-2) have been used to stimulate bone formation. LLLI stimulates proliferation of osteoblast precursor cells and cell differentiation and rhBMP-2 recruits osteoprogenitor cells to the bone healing area. This in vivo study evaluated the effects of LLLI and rhBMP-2 on the bone healing process in rats. Critical bone defects were created in the parietal bone in 42 animals, and the animals were divided into six treatment groups: (1) laser, (2) 7 mu g of rhBMP-2, (3) laser and 7 mu g of rhBMP-2, (4) 7 mu g of rhBMP-2/monoolein gel, (5) laser and 7 mu g rhBMP-2/monoolein gel, and (6) critical bone defect controls. A gallium-aluminum-arsenide diode laser was used (wavelength 780 nm, output power 60 mW, beam area 0.04 cm(2), irradiation time 80 s, energy density 120 J/cm(2), irradiance 1.5 W/cm(2)). After 15 days, the calvarial tissues were removed for histomorphometric analysis. Group 3 defects showed higher amounts of newly formed bone (37.89%) than the defects of all the other groups (P < 0.05). The amounts of new bone in defects of groups 1 and 4 were not significantly different from each other (24.00% and 24.75%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). The amounts of new bone in the defects of groups 2 and 5 were not significantly different from each other (31.42% and 31.96%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). Group 6 defects had 14.10% new bone formation, and this was significantly different from the amounts in the other groups (P < 0.05). It can be concluded that LLLI administered during surgery effectively accelerated healing of critical bone defects filled with pure rhBMP-2, achieving a better result than LLLI alone or the use of rhBMP-2 alone.

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The aim of this study was to compare retrospectively the effect of three different treatments on the healing outcome of bisphosphonate-related osteonecrosis of the jaws (BRONJ) in cancer patients. Twenty-two cancer patients were treated for BRONJ with one of the following protocols: clinical (pharmacological therapy), surgical (pharmacological plus surgical therapy), or PRP plus LPT (pharmacological plus surgical plus platelet rich plasma (PRP) plus laser phototherapy (LPT). The laser treatment was applied with a continuous diode laser (InGaAlP, 660 nm) using punctual and contact mode, 40 mW, spot size 0.042 cm(2), 6 J/cm(2) (6 s) and total energy of 0.24 J per point. The irradiations were performed on the exposed bone and surrounding soft tissue. The analysis of demographic data and risk factors was performed by gathering the following information: age, gender, primary tumor, bisphosphonate (BP) used, duration of BP intake, history of chemotherapy, use of steroids, and medical history of diabetes. The association between the current state of BRONJ (with or without bone exposure) and other qualitative variables was determined using the chi-square or Fisher's exact test. In all tests, the significance level adopted was 5%. Most BRONJ lesions occurred in the mandible (77%) after tooth extraction (55%) and in women (72%). A significantly higher percentage of patients reached the current state of BRONJ without bone exposure (86%) in the PPR plus LPT group than in the pharmacological (0%) and surgical (40%) groups after 1-month follow-up assessment. These results suggest that the association of pharmacological therapy and surgical therapy with PRP plus LPT significantly improves BRONJ healing in oncologic patients. Although prospective studies with larger sample sizes are still needed, this preliminary study may be used to inform a better-designed future study. (C) 2011 Elsevier Ltd. All rights reserved.

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Abstract Background It has been speculated that the biostimulatory effect of Low Level Laser Therapy could cause undesirable enhancement of tumor growth in neoplastic diseases. The aim of the present study is to analyze the behavior of melanoma cells (B16F10) in vitro and the in vivo development of melanoma in mice after laser irradiation. Methods We performed a controlled in vitro study on B16F10 melanoma cells to investigate cell viability and cell cycle changes by the Tripan Blue, MTT and cell quest histogram tests at 24, 48 and 72 h post irradiation. The in vivo mouse model (male Balb C, n = 21) of melanoma was used to analyze tumor volume and histological characteristics. Laser irradiation was performed three times (once a day for three consecutive days) with a 660 nm 50 mW CW laser, beam spot size 2 mm2, irradiance 2.5 W/cm2 and irradiation times of 60s (dose 150 J/cm2) and 420s (dose 1050 J/cm2) respectively. Results There were no statistically significant differences between the in vitro groups, except for an increase in the hypodiploid melanoma cells (8.48 ± 1.40% and 4.26 ± 0.60%) at 72 h post-irradiation. This cancer-protective effect was not reproduced in the in vivo experiment where outcome measures for the 150 J/cm2 dose group were not significantly different from controls. For the 1050 J/cm2 dose group, there were significant increases in tumor volume, blood vessels and cell abnormalities compared to the other groups. Conclusion LLLT Irradiation should be avoided over melanomas as the combination of high irradiance (2.5 W/cm2) and high dose (1050 J/cm2) significantly increases melanoma tumor growth in vivo.

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Abstract Background Recent reviews have indicated that low level level laser therapy (LLLT) is ineffective in lateral elbow tendinopathy (LET) without assessing validity of treatment procedures and doses or the influence of prior steroid injections. Methods Systematic review with meta-analysis, with primary outcome measures of pain relief and/or global improvement and subgroup analyses of methodological quality, wavelengths and treatment procedures. Results 18 randomised placebo-controlled trials (RCTs) were identified with 13 RCTs (730 patients) meeting the criteria for meta-analysis. 12 RCTs satisfied half or more of the methodological criteria. Publication bias was detected by Egger's graphical test, which showed a negative direction of bias. Ten of the trials included patients with poor prognosis caused by failed steroid injections or other treatment failures, or long symptom duration or severe baseline pain. The weighted mean difference (WMD) for pain relief was 10.2 mm [95% CI: 3.0 to 17.5] and the RR for global improvement was 1.36 [1.16 to 1.60]. Trials which targeted acupuncture points reported negative results, as did trials with wavelengths 820, 830 and 1064 nm. In a subgroup of five trials with 904 nm lasers and one trial with 632 nm wavelength where the lateral elbow tendon insertions were directly irradiated, WMD for pain relief was 17.2 mm [95% CI: 8.5 to 25.9] and 14.0 mm [95% CI: 7.4 to 20.6] respectively, while RR for global pain improvement was only reported for 904 nm at 1.53 [95% CI: 1.28 to 1.83]. LLLT doses in this subgroup ranged between 0.5 and 7.2 Joules. Secondary outcome measures of painfree grip strength, pain pressure threshold, sick leave and follow-up data from 3 to 8 weeks after the end of treatment, showed consistently significant results in favour of the same LLLT subgroup (p < 0.02). No serious side-effects were reported. Conclusion LLLT administered with optimal doses of 904 nm and possibly 632 nm wavelengths directly to the lateral elbow tendon insertions, seem to offer short-term pain relief and less disability in LET, both alone and in conjunction with an exercise regimen. This finding contradicts the conclusions of previous reviews which failed to assess treatment procedures, wavelengths and optimal doses.

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Background The increase in fructose consumption is paralleled by a higher incidence of metabolic syndrome, and consequently, cardiovascular disease mortality. We examined the effects of 8 weeks of low intensity exercise training (LET) on metabolic, hemodynamic, ventricular and vascular morphological changes induced by fructose drinking in male rats. Methods Male Wistar rats were divided into (n = 8 each) control (C), sedentary fructose (F) and ET fructose (FT) groups. Fructose-drinking rats received D-fructose (100 g/l). FT rats were assigned to a treadmill training protocol at low intensity (30% of maximal running speed) during 1 h/day, 5 days/week for 8 weeks. Measurements of triglyceride concentrations, white adipose tissue (WAT) and glycemia were carried out together with insulin tolerance test to evaluate metabolic profile. Arterial pressure (AP) signals were directly recorded. Baroreflex sensitivity (BS) was evaluated by the tachycardic and bradycardic responses. Right atria, left ventricle (LV) and ascending aorta were prepared to morphoquantitative analysis. Results LET reduced WAT (−37.7%), triglyceride levels (−33%), systolic AP (−6%), heart weight/body weight (−20.5%), LV (−36%) and aortic (−76%) collagen fibers, aortic intima-media thickness and circumferential wall tension in FT when compared to F rats. Additionally, FT group presented improve of BS, numerical density of atrial natriuretic peptide granules (+42%) and LV capillaries (+25%), as well as the number of elastic lamellae in aorta compared with F group. Conclusions Our data suggest that LET, a widely recommended practice, seems to be particularly effective for preventing metabolic, hemodynamic and morphological disorders triggered by MS.

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Temporomandibular disorders (TMD) are characterized by the presence of temporomandibular joint (TMJ) and/or masticatory muscle pain and dysfunction. Low-level laser is presented as an adjuvant therapeutic modality for the treatment of TMD, especially when the presence of inflammatory pain is suspected. Objective: To systematically review studies that investigated the effect of low level laser therapy (LLLT) on the pain levels in individuals with TMD. Material and Methods: The databases Scopus, embase, ebsco and PubMed were reviewed from January/2003 to October/2010 with the following keywords: laser therapy, low-level laser therapy, temporomandibular joint disorders, temporomandibular joint dysfunction syndrome, temporomandibular joint, temporomandibular, facial pain and arthralgia, with the inclusion criteria for intervention studies in humans. exclusion criteria adopted were intervention studies in animals, studies that were not written in english, Spanish or Portuguese, theses, monographs, and abstracts presented in scientific events. Results: After a careful review, 14 studies fit the criteria for inclusion, of which, 12 used a placebo group. As for the protocol for laser application, the energy density used ranged from 0.9 to 105 J/cm², while the power density ranged from 9.8 to 500 mW. The number of sessions varied from 1 to 20 and the frequency of applications ranged from daily for 10 days to 1 time per week for 4 weeks. A reduction in pain levels was reported in 13 studies, with 9 of these occurring only in the experimental group, and 4 studies reporting pain relief for both the experimental group and for the placebo. Conclusion: Most papers showed that LLLT seemed to be effective in reducing pain from TMD. However, the heterogeneity of the standardization regarding the parameters of laser calls for caution in interpretation of these results. Thus, it is necessary to conduct further research in order to obtain a consensus regarding the best application protocol for pain relief in patients with TMD.

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Intestinal ischemia and reperfusion (i-I/R) is an insult associated with acute respiratory distress syndrome (ARDS). It is not known if pro- and anti-inflammatory mediators in ARDS induced by i-I/R can be controlled by low-level laser therapy (LLLT). This study was designed to evaluate the effect of LLLT on tracheal cholinergic reactivity dysfunction and the release of inflammatory mediators from the lung after i-I/R. Anesthetized rats were subjected to superior mesenteric artery occlusion (45 min) and killed after clamp release and preestablished periods of intestinal reperfusion (30 min, 2 or 4 h). The LLLT (660 nm, 7.5 J/cm(2)) was carried out by irradiating the rats on the skin over the right upper bronchus for 15 and 30 min after initiating reperfusion and then euthanizing them 30 min, 2, or 4 h later. Lung edema was measured by the Evans blue extravasation technique, and pulmonary neutrophils were determined by myeloperoxidase (MPO) activity. Pulmonary tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), intercellular adhesion molecule-1 (ICAM-1), and isoform of NO synthase (iNOS) mRNA expression were analyzed by real-time PCR. TNF-α, IL-10, and iNOS proteins in the lung were measured by the enzyme-linked immunoassay technique. LLLT (660 nm, 7.5 J/cm(2)) restored the tracheal hyperresponsiveness and hyporesponsiveness in all the periods after intestinal reperfusion. Although LLLT reduced edema and MPO activity, it did not do so in all the postreperfusion periods. It was also observed with the ICAM-1 expression. In addition to reducing both TNF-α and iNOS, LLLT increased IL-10 in the lungs of animals subjected to i-I/R. The results indicate that LLLT can control the lung's inflammatory response and the airway reactivity dysfunction by simultaneously reducing both TNF-α and iNOS.

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Low level laser therapy is used as a treatment of several conditions, including inflammatory processes and wound healing. Possible changes in mechanical properties of cells, caused by illumination, are investigated with optical magnetic twisting cytometry (OMTC), which is a technique used to evaluate mechanical properties in cell culture. Ferromagnetic micro beads are bound to cell cytoskeleton, the beads are magnetized vertically and a horizontal twisting magnetic field is applied causing a torque that moves the beads and deforms the cell, the beads rotate and displace. Based on the lateral displacement of the beads, elastic shear and loss moduli are obtained. Samples of human bronchial epithelial cell culture were divided in two groups: one was illuminated with a 660 nm red laser, 30 mW power, 0.75 W/cm2 irradiance, during different time intervals, and the other one, the control group, was not illuminated. The values of the mechanical constants of the cells of the control group showed a tendency of increasing with the time out of the incubator. On the other hand, the illuminated group showed constancy on the behavior of both moduli, keeping the normal conditions of the cell culture. Those results indicate that illumination can induce cells to homeostasis, and OMTC is sensitive to observe departures from the steady conditions. Hence, OMTC is an important technique which can be used to aggregate knowledge on the light effect in cell cytoskeleton and even on the low level laser therapy mechanisms in inflammatory processes and/or wound healing.