Alberto Neto

Effect of Low-Level Laser Therapy (660 nm) on Angiogenesis in Wound Healing: A Immunohistochemical Study in a Rodent Model

The aim of the present investigation was to evaluate the angiogenesis on dorsal cutaneous wounds in a rodent model treated with λ660 nm laser light. New vessel formation is a multistep process involving vessel sprouting, endothelial cell migration, proliferation and tube formation. Although several in vivo studies have shown that laser phototherapy influences tissue repair, a fully understanding of angiogenesis mechanisms are not yet known. Twenty-four young adult male Wistar rats weighing between 200 and 250 g were used. Under general anesthesia, one excisional wound was created on the dorsum of each animal and they were randomly distributed into two groups: one control and one treated with laser (λ660 nm, 16 mW, 10 J/cm2). Each group was subdivided into three subgroups according to the animal death timing (2, 4 and 6 days). Laser irradiation started immediately after surgery and was repeated every other day during the experiment and marked with Sirius Red, specific for collagen, and immunomarked with anti-TGF-β and anti-von Willebrand factor. Marked sections underwent histological analysis by light microscopy and the mean area of the wound of each animal was calculated and analyzed by ANOVA and Tukeys test (α=0.05). Although at some death periods, collagen expression and number of blood vessels on irradiated animals were higher than in the control ones, no significant differences were found at any time in relation to TGF-β expression (p>0.05). It was concluded that laser treatment (λ660 nm) contributed to increase angiogenesis.

Altered expression of cytokeratins in primary, recurrent and syndrome keratocystic odontogenic tumors.

Keratocystic odontogenic tumor (KOT) is a benign cystic tumor that affects the jaw bones and may be associated with the nevoid basal cell carcinoma syndrome (NBCCS). Twenty-five cases diagnosed as KOT, including primary and recurrent tumors and those associated with NBCCS, were submitted to immunohistochemical study for analysis of cytokeratins (CKs) 7, 8, 10, 13, 14, 18 and 19. The results showed CK13 immunostained on the intermediate layers and upper cells. CK14 was expressed in all epithelial layers and in those areas where inflammation and subepithelial splits were present; this protein was preserved within the basal cells. CK 18 was expressed mainly in the basal layer, whereas CK19 was expressed mainly on the intermediate and superficial layers. The remaining CKs tested were not immuoreactive. The status of maturation of cytokeratin seems to be altered on KOTs, and this is not distinct when different tumors are compared.

Effect of LED Phototherapy (λ700 ± 20 nm) on TGF-β Expression During Wound Healing: An Immunohistochemical Study in a Rodent Model

OBJECTIVE The aim of the present investigation was to evaluate transforming growth factor β (TGF-β) expression on cutaneous wounds in rodents treated or not treated with LED light. BACKGROUND TGF-β is a multifunctional cytokine that presents a central action during tissue repair. Although several studies both in vitro and in vivo have shown that LED phototherapy influences tissue repair, a full understanding of the mechanisms involved in its usage, such as in the modulation of some growth factors, remains unclear. MATERIALS AND METHODS Under general anesthesia, 24 young adult male Wistar rats weighing 200-250 g had one excisional wound created on the dorsum of each, and were randomly distributed into two groups: G0 (Control) and G1 (LED, λ700 ± 20 nm, 16 mW, SAEF = 5 J/cm(2), Illuminated Area = 2 cm(2), 8 mWcm(2), 626 s) Each group was subdivided into three subgroups according to the animal death timing (2, 4, and 6 days). LED phototherapy started immediately after surgery and was repeated every other day during the experimental time. Following animal death, specimens were removed, routinely processed to wax, cut and immunomarked with polyclonal anti-TGF-β, and underwent histological analysis by light microscopy. The mean area of expression of each group was calculated. The data were statistically analyzed using ANOVA and Tukeys test. RESULTS The area of the expression of TGF-β on LED-irradiated animals was significantly smaller than on controls at day 2 (p = 0.013). No significant difference was found at later times. It is concluded that the use of LED light, at these specific parameters, caused an inhibition of the expression of TGF-β at an early stage of the healing process.

Influence of Laser Therapy and Muscle Relaxant on the Masseter Muscle under Occlusal Wear: An Ultrastructural Study

El objetivo del estudio fue analizar la influencia de la terapia laser de baja intensidad y del relajante muscular sobre las caracteristicas ultraestructurales del musculo masetero en el desgaste oclusal. 40 ratas macho Wistar, se dividieron al azar en cuatro grupos: grupo de control (GI), desgaste oclusal (G-II), laserterapia desgaste oclusal (G-III), y relajante muscular desgaste oclusal (G-IV). Bajo anestesia general por via intraperitoneal, los animales de los grupos II, III y IV sufrieron amputacion unilateral de las cuspides de los molares superiores e inferiores para simular una situacion de desgaste oclusal. El musculo masetero del G-III recibio la terapia con laser (830nm, 4J/cm2, 40mW, f ~ 2mm) despues del procedimiento el cual se repitio durante 14/30 dias. Los animales del G-IV fueron tratados con una inyeccion diaria de Dantroleno® (2,5 mg/Kg en 0,5 ml de H2O). Los animales fueron sacrificados con una sobredosis de anestesia general en los dias 14 y 30. Despues de la remocion de las cuspides el musculo masetero ipsilateral se extirpo y se dividio en dos, una mitad fue procesada para microscopia de luz y la otra para microscopia electronica. No hubo diferencias estadisticamente significativas entre cada grupo experimental y el control, asi como, entre los periodos en cada grupo experimental. Sin embargo, las fibras musculares en el G-II mostraron los cambios mas pronunciados. En conclusion no existe relacion causal entre las lesiones de las fibras musculares y la oclusion, a pesar que los signos de lesion de los tejidos musculares fue mas evidente en el grupo con desgaste oclusal. Los resultados indican una accion moderada ejercida por la terapia laser y de los relajantes musculares sobre el musculo esqueletico.

Orthokeratinized odontogenic cyst: a report of two cases in the mandible

PURPOSE: To describe the behavior clinical and pathological features of two cases of odontogenic cyst orthokeratinized. CASE DESCRIPTION: In case 1, a 17-year-old woman presented hard and painless swelling in the left posterior mandible. Radiographically, a radiolucent area with a radiopaque was observed. A clinical diagnosis of ameloblastoma or odontogenic keratocystic tumor was established. The histopathological examination revealed an orthokeratinized odontogenic cyst. In case 2, a 23-year-old woman presented a radiolucent lesion surrounded by radiopaque halo symmetrically distributed on both partially erupted lower third molars. A clinical diagnosis of bilateral dentigerous cyst (DC) was rended. The histopathological examination showed bilateral orthokeratinized odontogenic cyst. CONCLUSION: Orthokeratinized odontogenic cyst should be considered in the differential diagnosis of lesions occurring in the jawbones associated with an impacted tooth, particularly those cases simulating dentigerous cyst. In addition, we observed the importance of radiographs taken prior to orthodontic treatment as an important tool in the diagnosis of oral pathologies. Performing routine radiograph is of high clinical value, especially before orthodontic treatment.