The use of a high-power laser on swine mitral valve chordae tendineae.

Worldwide, rheumatic fever remains a significant cause of mitral valve insufficiency. It is responsible for approximately 90 % of early childhood valvular surgeries in Brazil. Elongated or flail chordae are frequently responsible and require surgical correction. The purpose of this study was to analyze and compare the histological tissues of the mitral valve chordae and the mechanical resistance generated by the chordae, both with and without the application of a high-power laser. Twenty normal porcine mitral valve chordae were measured and divided randomly into the following two groups: control group (not subjected to a high-power laser) and laser group (subjected to photonic irradiation). Laser surgery was performed under controlled conditions, using following parameters: λ = 980-nm wavelength, power = 3 W, and energy = 60 J. A mechanical test machine was used in combination with a subsequent histological study to measure chordae tensile properties. A histological analysis demonstrated a typical collagen bundle arrangement in the control group; however, under a particular reached temperature range (48), the collagen bundles assumed different arrangements in the laser group. Significant reductions in the chordae tendineae lengths and changes in their resistance in the laser group were observed, as these chordae exhibited less rigid fibers. The chordae tendineae of normal porcine valves subjected to a high-power laser exhibited its length reduction and less stiffness compared to the control group. A histological analysis of the laser treatment specimens demonstrated differences in collagen bundle spatial organization, following slight changes into tissue temperature.

Prevention and treatment of mice paw edema by near-infrared low-level laser therapy on lymph nodes.

Low-level laser therapy (LLLT) has been demonstrated to modulate inflammatory processes and immunological responses. The aim of this work was to investigate the hypothesis that near infrared LLLT (830 nm) over lymph nodes may reduce paw edema and contribute to the modulation of inflammation. The edema was induced by carrageenan inoculation (CGN) into the plantar surface of 100 male mice left hind paw. Animals were divided into five groups: CGN (control), no treatment; Diclo, sodium diclofenac; Paw, LLLT on the paw; Ly, LLLT on the inguinal lymph nodes; and Paw+Ly, LLLT in both paw and lymph nodes, and subdivided according to moment of irradiation: A-1 h and 2 h before CGN, B-1 h and immediately before CGN, C-1 and 2 h after CGN, and D-3.5 and 4.5 h after CGN. The parameters used were: energy=1 J, fluence=35 J/cm(2), power=100 mW during 10 s. Paw volume was measured before and 1 to 6 h after CGN, and myeloperoxidase (MPO) activity was analyzed. Edema prevention was obtained by the irradiation of Paw+Ly at moment A and at Ly at moment B, inhibition of edema formation was achieved by either Paw or Ly at moment C, and edema treatment was obtained by Paw or Ly at moment D (p<0.05). MPO activity was significantly reduced on Paw at moment A, Paw and Ly on C, and in all irradiated groups on B and D. Our results suggest that LLLT was able to produce both anti-inflammatory and pro-inflammatory effects depending on to the site and moment of irradiation.

Descriptive Analysis of In Vitro Cutting of Swine Mitral Cusps: Comparison of High-Power Laser and Scalpel Blade Cutting Techniques.

BACKGROUND AND OBJECTIVES: The most common injury to the heart valve with rheumatic involvement is mitral stenosis, which is the reason for a big number of cardiac operations in Brazil. Commissurotomy is the traditional technique that is still widely used for this condition, although late postoperative restenosis is concerning. This study's purpose was to compare the histological findings of porcine cusp mitral valves treated in vitro with commissurotomy with a scalpel blade to those treated with high-power laser (HPL) cutting, using appropriate staining techniques. MATERIALS AND METHODS: Five mitral valves from healthy swine were randomly divided into two groups: Cusp group (G1), cut with a scalpel blade (n = 5), and Cusp group (G2), cut with a laser (n = 5). G2 cusps were treated using a diode laser (λ = 980 nm, power = 9.0 W, time = 12 sec, irradiance = 5625 W/cm2, and energy = 108 J). RESULTS: In G1, no histological change was observed in tissue. A hyaline basophilic aspect was focally observed in G2, along with a dark red color on the edges and areas of lower birefringence, when stained with hematoxylin-eosin, Masson's trichrome, and Sirius red. Further, the mean distances from the cutting edge in cusps submitted to laser application and stained with Masson's trichrome and Sirius red were 416.7 and 778.6 µm, respectively, never overcoming 1 mm in length. CONCLUSIONS: Thermal changes were unique in the group submitted to HPL and not observed in the cusp group cut with a scalpel blade. The mean distance of the cusps' collagen injury from the cutting edge was less than 1 mm with laser treatment. Additional studies are needed to establish the histological evolution of the laser cutting and to answer whether laser cutting may avoid valvular restenosis better than blade cutting.

Experimental study of the neurotoxic effects of photodynamic therapy on the spinal cord / Estudo experimental dos efeitos neurotóxicos da terapia fotodinâmica na medula espinhal / Estudio experimental de los efectos neurotóxicos de la terapia fotodinámica en la médula espinal

ABSTRACT Objective To evaluate the effects of photodynamic therapy (PDT) on the dura mater using the photosensitizers aluminum chloride phthalocyanine and methylene blue in in vivo assays. Methods Fifty-six male Wistar rats were divided into two groups; one submitted to PDT and the other submitted to the photosensitizers without their photoactivation (control). The photosensitizers were applied to the dura mater after laminectomy at the T10 level. The methods used for assessment were the Basso, Beattie and Bresnahan (BBB) functional evaluation scale and study of the dura mater by light microscopy. Results No changes in motor activity were observed in the animals submitted to PDT compared to control. Histological and pathological evaluation did not show any differences between the group exposed to activated photosensitizers and the control group with regard to the inflammatory process and tissue necrosis. Conclusion The joint use of PDT with the photosensitizing pharmaceuticals aluminum chloride phthalocyanine and methylene blue did not induce any clinical neurotoxic effects or histological changes in the dura mater of the animals studied. Level de evidence V; Expert Opnion.

RESUMO Objetivo Avaliar os efeitos da terapia fotodinâmica (PDT) na dura-máter usando os fotossensibilizadores cloreto de alumínio ftalocianina e azul de metileno em ensaios in vivo. Métodos Cinquenta e seis ratos Wistar machos divididos em dois grupos; um submetido à PDT e o outro submetido aos fotossensibilizadores sem a fotoativação (controle). Os fotossensibilizadores foram aplicados sobre a dura-máter depois de laminectomia no nível T10. Os métodos de avaliação usados foram a escala de avaliação funcional de Basso, Beattie e Bresnahan (BBB) e o estudo da dura-máter por microscopia óptica. Resultados Não foram observadas alterações da atividade motora dos animais submetidos à PDT com relação ao grupo controle. A avaliação histológica e histopatológica não mostrou diferenças entre o grupo exposto aos fotossensibilizadores ativados e o grupo controle, com relação ao processo inflamatório e à necrose tecidual. Conclusões O uso conjunto de PDT e os fármacos fotossensibilizantes cloreto de alumínio ftalocianina e azul de metileno não induziu efeitos neurotóxicos clínicos e/ou alterações histológicas sobre a dura-máter dos animais estudados. Nível de evidência V; Opinião de Especialista.

RESUMEN Objetivo Evaluar los efectos de la terapia fotodinámica (PDT) en la duramadre utilizando los fotosensibilizadores de ftalocianina de aluminio clorada y azul de metileno en ensayos in vivo. Métodos Cincuenta y seis ratas Wistar machos se dividieron en 2 grupos; uno fue sometido a PDT y el otro sometido a fotosensibilizadores sin fotoactivación (control). Los fotosensibilizadores se aplicaron a la duramadre después de la laminectomía en el nivel T10. Los métodos de evaluación utilizados fueron la escala de evaluación funcional de Basso, Beattie y Bresnahan (BBB) y el estudio de la duramadre mediante microscopía óptica. Resultados No hubo cambios en la actividad motora de los animales sometidos a PDT en relación con el grupo de control. La evaluación histológica e histopatológica no mostró diferencias entre el grupo expuesto a fotosensibilizadores activados y el grupo de control con respecto al proceso inflamatorio y la necrosis tisular. Conclusiones El uso conjunto de PDT con las sustancias fotosensibilizadores ftalocianina de aluminio clorada y azul de metileno no indujo efectos neurotóxicos clínicos o cambios histológicos en la duramadre de los animales estudiados. Nivel de evidencia V; Opinión del Especialista.

Resultados de médio e longo prazo do tratamento endovenoso de varizes com laser de diodo em 1940 nm: análise crítica e considerações técnicas / Medium and long-term outcomes of endovenous treatment of varicose veins with a 1940nm diode laser: critical analysis and technical considerations

Resumo Contexto Desde a introdução do laser endovenoso para tratamento das varizes, há uma busca pelo comprimento de onda ideal, capaz de produzir o maior dano seletivo possível com maior segurança e menor incidência de efeitos adversos. Objetivos Avaliar os resultados de médio e longo prazo do laser de diodo de 1940 nm no tratamento de varizes, correlacionando os parâmetros utilizados com a durabilidade do desfecho anatômico. Métodos Revisão retrospectiva de pacientes diagnosticados com insuficiência venosa crônica em estágio clínico baseado em clínica, etiologia, anatomia e patofisiologia (CEAP) C2 a C6, submetidos ao tratamento termoablativo endovenoso de varizes tronculares, com laser com comprimento de onda em 1940 nm com fibra óptica de emissão radial, no período de abril de 2012 a julho de 2015. Uma revisão sistemática dos registros médicos eletrônicos foi realizada para obter dados demográficos e dados clínicos, incluindo dados de ultrassom dúplex, durante o período de seguimento pós-operatório. Resultados A média de idade dos pacientes foi de 53,3 anos; 37 eram mulheres (90,2%). O tempo médio de seguimento foi de 803 dias. O calibre médio das veias tratadas foi de 7,8 mm. A taxa de sucesso imediato foi de 100%, com densidade de energia endovenosa linear (linear endovenous energy density, LEED) média de 45,3 J/cm. A taxa de sucesso tardio foi de 95,1%, com duas recanalizações por volta de 12 meses pós-ablação. Não houve nenhuma recanalização nas veias tratadas com LEED superior a 30 J/cm. Conclusões O laser 1940 nm mostrou-se seguro e efetivo, em médio e longo prazo, para os parâmetros propostos, em segmentos venosos com até 10 mm de diâmetro.

Abstract Background Introduction of the endovenous laser technique for treatment of varicose veins triggered a efforts to identify an ideal wavelength, capable of producing the highest possible selective damage with the greatest safety and lowest incidence of adverse effects. Objectives Assess medium to long term results of 1940nm diode laser treatment of varicose veins, correlating parameters used with durability of the anatomic outcome. Methods This was a retrospective study of patients diagnosed with Chronic Venous Insufficiency at clinical stages CEAP C2 to C6 who underwent thermoablative treatment of trunk varicose veins using a 1940nm wavelength laser with a radial emission optical fiber, from April 2012 to July 2015. A systematic review was conducted of electronic medical records to obtain demographic and clinical data, including postoperative follow-up duplex ultrasound findings. Results The average age of the 41-patient sample was 53.3 years and 37 patients were women (90.2%). The average follow-up time was 803 days. The average caliber of the treated veins was 7.8 mm. The immediate success rate was 100% with an average LEED of 45.3 J/cm. The late success rate was 95.1%, and two recanalizations were observed around 12 months after ablation. There was no recanalization in veins treated with a LEED greater than 30 J/cm. Conclusions The 1940nm laser proved to be safe and effective in venous segments up to 10 mm in diameter, with the parameters proposed, over medium to long term time follow-up.

Low-level laser therapy in the prevention and treatment of chemotherapy-induced oral mucositis in young patients.

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. MATERIALS AND METHODS: Patients undergoing chemotherapy (22 cycles) without mucositis were randomized 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 purposes (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.

Avaliação in vitro do metabolismo de celulas imortalizadas de linhagem odontoblástica MDPC-23 submetidas à aplicação do laser de baixa potência / In vitro evaluation of the metabolism of the immortalized odontoblast-like cells MDPC-23 submitted to the low power laser therapy

Desde que o laser interage com os tecidos, agindo como biomodulador e bioestimuladordo processo de reparação, é de se esperar que a terapia com a luz laser possa, de alguma maneira,estimular o metabolismo dos odontoblastos, ativando a síntese de proteínas específicas. Objetivo:avaliar a atividade metabólica das células odontoblastóides MDPC-23 ante à estimulação comlaser de baixa intensidade. Material e Método: Células MDPC-23 foram cultivadas em situaçãonormal ou associadas à deficiência nutricional parcial (baixas concentrações de soro fetal bovino- 2,5 e 5%), e, então, foram submetidas à aplicação de luz laser com comprimentos de onda de 830nm no infravermelho (AsGaAl) e de 685 nm na luz visível (InGaAlP), ambos emitindo radiaçãocontínua e pontual. Finalmente, o metabolismo dessas células foi avaliado pelo teste de MTT, sendoos valores numéricos obtidos submetidos à análise estatística. Resultado: Foi demonstrado que,de acordo com os padrões de irradiação utilizados para este experimento, não houve um aumentosignificante no metabolismo celular. Conclusão: Foi possível concluir, dentro das condiçõesexperimentais, que o metabolismo das células odontoblastóides MDPC-23 é biomodulado pelolaser vermelho e infravermelho próximo quando essas células são colocadas em estado de estressepor deficiência nutricional.

Since the laser light acts as bio-modulator and bio-stimulator of the healing process,one may expect that a specific laser therapy could also stimulate the odontoblasts to synthesizeand deposit dentinal matrix in order to prevent in vivo dentinal sensitivity. Objective: The aimof this study was to evaluate the metabolic activity of an odontoblast-cell line (MDPC-23)submitted to the low power laser therapy. Material and Methods: MDPC-23 cells were platted(3 x 104 cells/cm2) and incubated with complete medium (10% fetal bovine serum – FBS) orwith nutritional deficiency (2.5% FBS or 5% FBS) in order to simulate stress conditions for theMDPC-23 cells. The cells were suibmitted to the laser irradiation by using wave lengths of 830 nmin the infra-red ray (AsGaAl) or 685 nm in the visible light (InGaAlP), both emitting continuousand punctual radiation. Finally, the cell metabolism was evaluated by the MTT assay and thenumerical scores obtained were submitted to the statistical analysis. Results: It was demonstratedthat the standardized experimental techniques of irradiation employed in this experiment causedno significant increase in the cell metabolism. Conclusion: According to the experimental conditions, it was possible to conclude the metabolism of the MDPC-23 odontoblastic-like cellsis bio-modulated by the red laser and next infra-red ray when these cells are in stress conditioninduced by nutritional deficiency.