***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Use of the low-energy helium-neon laser ( LEL ) appears to be a simple atraumatic technique for the prevention and treatment of mucositis of various origins . Preliminary findings , and significant results obtained for chemotherapy-induced mucositis in a previous phase III study , prompted a r and omized multicenter double-blind trial to evaluate LEL in the prevention of acute radiation-induced stomatitis . Irradiation by LEL corresponds to local application of a high-photon-density monochromatic light source . Activation of epithelial healing for LEL-treated surfaces , the most commonly recognized effect , has been confirmed by numerous in vitro studies . The mechanism of action at a molecular and enzymatic level is presently being studied . From September 1994 to March 1998 , 30 patients were r and omized . Technical specification : 60 mW ( 25 mW at Reims , 1 patient ) , He-Ne , wavelength 632.8 nm . The trial was open to patients with carcinoma of the oropharynx , hypopharynx and oral cavity , treated by radiotherapy alone ( 65 Gy at a rate of 2 Gy/fraction , 5 fractions per week ) without prior surgery or concomitant chemotherapy .  The malignant tumor had to be located outside the tested laser application areas ( 9 points ) : posterior third of the internal surfaces of the cheeks , soft palate and anterior tonsillar pillars . Patients were r and omized to LEL or placebo light treatment , starting on the first day of radiotherapy and before each session . The treatment time ( t ) for each application point was given by the equation : t (s)=energy (J/cm2) × surface (cm2)/Power ( W ) . Objective assessment of the degree of mucositis was recorded weekly by a physician blinded to the type of treatment , using the WHO scale for grading of mucositis and a segmented visual analogue scale for pain evaluation . Protocol feasibility and compliance were excellent . Grade 3 mucositis occured with a frequency of 35.2 % without LEL and of 7.6 % with LEL ( P<0.01 ) . The frequency of " severe pain " ( grade 3 ) was 23.8 % without LEL , falling to 1.9 % with LEL ( P<0.05 ) . Pain relief was significantly reduced throughout the treatment period ( weeks 2–7 ) . LEL therapy is capable of reducing the severity and duration of oral mucositis associated with radiation therapy . In addition , there is a tremendous potential for using LEL in combined treatment protocol s utilizing concomitant chemotherapy and radiotherapy Background . Oral mucositis is a common complication of bone marrow transplantation ( BMT ) conditioning therapy . Sequelae consist of increased risk for infection , moderate to severe pain , compromised oral function , and bleeding . This study investigated helium‐neon laser treatment for prevention of conditioning‐induced oral mucositis in  BMT patients .  Patterns and severity of mucositis for specific conditioning drug regimens also were analyzed Background Low-energy laser ( LEL ) treatment has been suggested as an effective and safe method to prevent and /or treat oral mucositis induced by chemotherapy and /or radiotherapy ; however , it has not gained wide acceptance so far . Material s and methods We conducted two clinical trials testing the LEL technique : firstly , as a secondary prevention in patients with various solid tumors treated with chemotherapy who all developed severe mucositis after a previous identical chemotherapy and , secondly , as therapeutic intervention ( compared to sham illumination in a r and omized way ) in patients with hematological tumors receiving intensive chemotherapy and having developed low- grade oral mucositis . Results We entered 26 eligible patients in the first study and 36 were r and omized in the second study . The success rate was 81 % ( 95%CI = 61–93 % ) when LEL was given as a preventive treatment . In the second study , in patients with existing lesions , the therapeutic success rate was 83 % ( 95%CI = 59–96 % ) , which was significantly different from the success rate reached in the sham-treated patients ( 11 % ; 95%CI = 1–35 % ) ; the time to development of grade 3 mucositis was also significantly shorter in the sham-treated patients ( p < 0.001 ) . Conclusion Our results strongly support the already available literature , suggesting that LEL is an effective and safe approach to prevent or treat oral mucositis result ing from cancer chemotherapy Abstract Background and Objective : As Light Emitting Diode ( LED ) devices are commercially introduced as an alternative for Low Level Laser ( LLL ) Therapy , the ability of LED in influencing wound healing processes at cellular level was examined . Study Design / Material s and Methods : Cultured fibroblasts were treated in a controlled , r and omized manner , during three consecutive days , either with an infrared LLL or with a LED light source emitting several wavelengths ( 950 nm , 660 nm and 570 nm ) and respective power outputs . Treatment duration varied in relation to varying surface energy densities ( radiant exposures ) . Results : Statistical analysis revealed a higher rate of proliferation ( p ≤ 0.001 ) in all irradiated cultures in comparison with the controls . Green light yielded a significantly higher number of cells , than red ( p ≤ 0.001 ) and infrared LED light ( p ≤ 0.001 ) and than the cultures irradiated with the LLL ( p ≤ 0.001 ) ; the red probe provided a higher increase ( p ≤ 0.001 ) than the infrared LED probe and than the LLL source . Conclusion : LED and LLL irradiation result ed in an increased fibroblast proliferation in vitro . This study therefore postulates possible stimulatory effects on wound healing in vivo at the applied dosimetric parameters We investigated the clinical effects of low-power laser therapy ( LPLT ) on prevention and reduction of severity of conditioning-induced oral mucositis ( OM ) for hematopoietic stem cell transplantation ( HSCT ) . We r and omized 38 patients who underwent autologous ( AT ) or allogeneic ( AL ) HSCT .  A diode InGaAlP was used , emitting light at 660 nm , 50 mW , and 4 J/cm2 , measured at the fiberoptic end with 0.196 cm2 of section area . The evaluation of OM was done using the Oral Mucositis Assessment Scale ( OMAS ) and the World Health Organization ( WHO ) scale . In the LPLT group , 94.7 % of patients had an OM grade ( WHO ) lower than or equal to grade 2 , including 63.2 % with grade 0 and 1 , whereas in the controls group , 31.5 % of patients had an OM grade lower than or equal to grade 2 ( P < .001 ) . Remarkably , the hazard ratio ( HR ) for grade s 2 , 3 , and 4 OM was 0.41 ( range , 0.22 - 0.75 ; P = .002 ) and for grade s 3 and 4 it was 0.07 ( range , 0.11 - 0.53 ; P < .001 ) . Using OMAS by the calculation of ulcerous area , 5.3 % of the laser group presented with ulcers of 9.1 cm2 to 18 cm2 , whereas 73.6 % of the control group presented with ulcers from 9.1 cm2 to 18 cm2 ( P = .003 ) . Our results indicate that the use of upfront LPLT in patients who have undergone HSCT is a powerful instrument in reducing the incidence of OM and is now st and ard in our center OBJECTIVE A pilot clinical study was conducted to evaluate the efficacy and feasibility of low-level laser therapy ( LLLT ) in the prevention and treatment of chemotherapy (CT)-induced oral mucositis ( OM ) in young patients . BACKGROUND DATA Besides compromising the patient 's nutrition and well-being , oral mucositis represents a portal of entry into the body for microorganisms present in the mouth , which may lead to sepsis if there is hematological involvement . Oncologic treatment tolerance decreases and systemic complications may arise that interfere with the success of cancer treatment . LLLT appears to be an interesting alternative to other approaches to treating OM , due to its trophic , anti-inflammatory , and analgesic properties . MATERIAL S AND METHODS Patients undergoing chemotherapy ( 22 cycles ) without mucositis were r and omized into a group receiving prophylactic laser-irradiation ( group 1 ) , and a group receiving placebo light treatment ( group 2 ) . Patients who had already presented with mucositis were placed in a group receiving irradiation for therapeutic purpose s ( group 3 , with 10 cycles of CT ) . Serum granulocyte levels were taken and compared to the progression of mucositis . RESULTS In group 1 , most patients ( 73 % ) presented with mucositis of grade 0 ( p = 0.03 when compared with the placebo group ) , and 18 % presented with grade 1 . In group 2 , 27 % had no OM and did not require therapy . In group 3 , the patients had marked pain relief ( as assessed by a visual analogue scale ) , and a decrease in the severity of OM , even when they had severe granulocytopenia . CONCLUSION The ease of use of LLLT , high patient acceptance , and the positive results achieved , make this therapy feasible for the prevention and treatment of OM in young patients Goal of workThe aim of this study was to investigate the mechanisms whereby low-intensity laser therapy may affect the  severity of oral mucositis .  Material s and methods A hamster cheek pouch model of oral mucositis was used with all animals receiving intraperitoneal 5-fluorouracil followed by surface irritation . Animals were r and omly allocated into three groups and treated with a 35 mW laser , 100 mW laser , or no laser .  Clinical severity of mucositis was assessed at four time-points by a blinded examiner . Buccal pouch tissue was harvested from a subgroup of animals in each group at four time-points . This tissue was used for immunohistochemistry for cyclooxygenase-2 ( COX-2 ) , vascular endothelial growth factor ( VEGF ) , and factor VIII ( marker of microvessel density ) and the result ing staining was quantified . Main results Peak severity of mucositis was reduced in the 35 mW laser group as compared to the 100 mW laser and control groups . This reduced peak clinical severity of mucositis in the 35 mW laser group was accompanied by a significantly lower level of COX-2 staining . The 100 mW laser did not have an effect on the severity of clinical mucositis , but was associated with a decrease in VEGF levels at the later time-points , as compared to the other groups . There was no clear relationship of VEGF levels or microvessel density to clinical mucositis severity . Conclusion The tissue response to laser therapy appears to vary by dose . Low-intensity laser therapy appears to reduce the severity of mucositis , at least in part , by reducing COX-2 levels and associated inhibition of the inflammatory response BACKGROUND AND OBJECTIVES Several studies have suggested that low-level laser therapy ( LLLT ) can ameliorate  oral mucositis ;  however , the mechanisms involved are not well understood . The aim of this study was to investigate the mechanisms of action of LLLT on chemotherapy-induced oral mucositis , as related to effects on collagen expression and inflammation . MATERIAL S AND METHODS A hamster cheek pouch model of oral mucositis was used with all animals receiving intraperitoneal 5-fluorouracil , followed by surface irritation . Animals were r and omly allocated into three groups , and treated with an InGaAIP diode laser at a wavelength of 660 nm and output power of 35 or 100 mW laser , or no laser .  Clinical severity of mucositis was assessed at four time-points by a blinded examiner . Buccal pouch tissue was harvested from a subgroup of animals in each group at four time-points . Collagen was qualitatively and quantitatively evaluated after picrosirius staining . The density of the neutrophil infiltrate was also scored . RESULTS Peak clinical severity of mucositis was reduced in the 35 mW laser group as compared to the 100 mW and control groups . The reduced peak clinical severity of mucositis in the 35 mW laser group was accompanied by a decrease in the number of neutrophils and an increase in the proportion of mature collagen as compared to the other two groups . The total quantity of collagen was significantly higher in the control ( no laser ) group at the day 11 time-point , as compared to the 35 mW laser group , consistent with a more prolonged inflammatory response in the control group . CONCLUSION This study supports two mechanisms of action for LLLT in reducing mucositis severity . The increase in collagen organization in response to the 35 mW laser indicates that LLLT promotes wound healing . In addition , LLLT also appears to have an anti-inflammatory effect , as evidence d by the reduction in neutrophil infiltrate The purpose of this prospect i ve study was to determine the effect of the low-level laser in the prevention and treatment of mucositis in head and neck cancer patients . A total of 70 patients with malignant neoplasms in the 
    Output:
    
Conclusions The increasing evidence in favor of low-level laser therapy allowed for the development of two new guidelines supporting this modality in the population s listed above .
Evidence for other population s was also generally encouraging over a range of wavelengths and intensities .