Laser therapy increases the proliferation of preosteoblastic MC3T3-E1 cells cultured on poly(lactic acid) films.

This study aimed to verify the efficacy of low-level laser irradiation (LLLI) on the proliferation of MC3T3-E1 preosteoblasts cultured on poly(lactic acid) (PLA) films. The produced films were characterized by contact angle tests, scanning electron microscopy (SEM), atomic force microscopy, differential scanning calorimetry, and X-ray diffraction. The MC3T3-E1 cells were cultured as three different groups: Control-cultured on polystyrene plastic surfaces; PLA-cultured on PLA films; and PLA + Laser-cultured on PLA films and submitted to laser irradiation (660 nm; 30 mW; 4 J/cm2 ). Cell proliferation was analyzed by Trypan blue and Alamar blue assays at 24, 48, and 72 h after irradiation. Cell viability was assessed by Live/Dead assay, apoptosis-related events were evaluated by Annexin V/propidium iodide (PI) expression, and cell cycle events were analyzed by flow cytometry. Cell morphology on the surface of films was assessed by SEM. Cell counting and biochemical assay results indicate that the PLA + Laser group exhibited higher proliferation (p < 0.01) when compared with the Control and PLA groups. The Live/Dead and Annexin/PI assays indicate increased cell viability in the PLA + Laser group that also presented a higher percentage of cells in the proliferative cell cycle phases (S and G2/M). These findings were also confirmed by the higher cell density observed in the irradiated group through SEM images. The evidence from this study supports the idea that LLLI increases the proliferation of MC3T3-E1 cells on PLA surfaces, suggesting that it can be potentially applied in bone tissue engineering.

Low-level laser irradiation induces in vitro proliferation of stem cells from human exfoliated deciduous teeth.

The aim of this study was to evaluate the effect of low-level laser irradiation (LLLI) on the proliferation and viability of stem cells from human exfoliated deciduous teeth (SHED). Cells were irradiated or not (control) with an InGaAlP laser diode (660 nm, 30 mW, continuous action mode) using two different energy densities (0.5 J/cm2-16 s; 1.0 J/cm2-33 s). Irradiation was performed at 0 and 48 h, with the laser probe fixed at a distance of 0.5 cm from the cells. Cell proliferation was analyzed at 0, 24, 48, and 72 h by the Trypan blue exclusion method and MTT assay. Cell cycle and Ki67 expression were analyzed by flow cytometry. Apoptosis-related events were evaluated by expression of annexin V/PI and nuclear morphological changes by staining with DAPI. Differences between groups at each time were analyzed by the Kruskal-Wallis and Mann-Whitney tests, adopting a level of significance of 5% (p < 0.05). The results showed that an energy density of 1.0 J/cm2 promoted an increase in cell proliferation at 48 and 72 h compared to the control and 0.5 J/cm2 groups. Cell cycle analysis revealed a predominance of cells in the S and G2/M phases in the irradiated groups. This finding was confirmed by the increased expression of Ki67. Low positive staining for annexin V and PI was observed in all groups, and no nuclear changes were detected, indicating that cell viability was not affected by the energy densities tested. It can be concluded that the LLLI parameters used (660 nm, 30 mW, 1.0 J/cm2) promote the proliferation of SHEDs and the maintenance of cell viability.

Low-level laser irradiation promotes proliferation of cryopreserved adipose-derived stem cells.

OBJECTIVE: To evaluate the effect of low-level laser irradiation on proliferation and viability of murine adipose-derived stem cells previously submitted to cryopreservation. METHODS: Adipose-derived stem cells were isolated from inguinal fat pads of three mice, submitted to cryopreservation in fetal bovine serum with 10% dimethylsulfoxide for 30 days and then thawed and maintained in normal culture conditions. Culture cells were either irradiated or not (control) with an InGaAIP diode laser at zero and 48 hours, using two different energy densities (0.5 and 1.0J/cm2). Cell proliferation was evaluated by trypan blue exclusion method and MTT assay at intervals of zero, 24, 48, and 72 hours after the first laser application. Cell viability and apoptosis of previously cryopreserved cells submitted to laser therapy were evaluated by flow cytometry. RESULTS: The Irradiated Groups (0.5 and 1.0J/cm2) showed an increased cell proliferation (p<0.05) when compared to the Control Group, however no significant difference between the two energy densities was observed. Flow cytometry revealed a percentage of viable cells higher than 99% in all groups. CONCLUSION: Low-level laser irradiation has stimulatory effects on the proliferation of adipose-derived stem cells previously submitted to cryopreservation.

Low-level laser irradiation promotes proliferation of cryopreserved adipose-derived stem cells / Laser de baixa intensidade promove proliferação de células-tronco derivadas de tecido adiposo criopreservadas

ABSTRACT Objective To evaluate the effect of low-level laser irradiation on proliferation and viability of murine adipose-derived stem cells previously submitted to cryopreservation. Methods Adipose-derived stem cells were isolated from inguinal fat pads of three mice, submitted to cryopreservation in fetal bovine serum with 10% dimethylsulfoxide for 30 days and then thawed and maintained in normal culture conditions. Culture cells were either irradiated or not (control) with an InGaAIP diode laser at zero and 48 hours, using two different energy densities (0.5 and 1.0J/cm2). Cell proliferation was evaluated by trypan blue exclusion method and MTT assay at intervals of zero, 24, 48, and 72 hours after the first laser application. Cell viability and apoptosis of previously cryopreserved cells submitted to laser therapy were evaluated by flow cytometry. Results The Irradiated Groups (0.5 and 1.0J/cm2) showed an increased cell proliferation (p<0.05) when compared to the Control Group, however no significant difference between the two energy densities was observed. Flow cytometry revealed a percentage of viable cells higher than 99% in all groups. Conclusion Low-level laser irradiation has stimulatory effects on the proliferation of adipose-derived stem cells previously submitted to cryopreservation.

RESUMO Objetivo Avaliar o efeito do laser de baixa intensidade na proliferação e na viabilidade de células-tronco derivadas de tecido adiposo murinas previamente submetidas à criopreservação. Métodos Células-tronco derivadas de tecido adiposo foram isoladas da região inguinal de três camundongos, submetidas à criopreservação em soro fetal bovino com 10% de dimetilsulfóxido por 30 dias e, depois, descongeladas e mantidas em condições normais de cultivo. As células cultivadas foram irradiadas ou não (controle) com um laser de diodo InGaAIP nos intervalos de zero e 48 horas, utilizando duas densidades de energia diferentes (0,5 e 1,0J/cm2). A proliferação celular foi avaliada pelo método de exclusão de azul de tripan e ensaio MTT, nos intervalos de zero, 24, 48 e 72 horas após a primeira aplicação do laser. A viabilidade celular e a apoptose das células previamente criopreservadas submetidas à laserterapia foram avaliadas por citometria de fluxo. Resultados Os Grupos Irradiados (0,5 e 1,0J/cm2) apresentaram aumento da proliferação celular (p<0,05) quando comparados ao Grupos Controle, porém não foi observada diferença significativa entre as duas densidades de energia. A citometria de fluxo revelou percentagem de células viáveis superior a 99% em todos os grupos. Conclusão O laser de baixa intensidade tem efeitos estimuladores sobre a proliferação de células-tronco derivadas de tecido adiposo previamente submetidas à criopreservação.

Modulation of in vitro osteoclast activity mediated by different doses of parathyroid hormone / Modulación in vitro de la actividad osteoclástica mediada por diferentes dosis de hormona paratiroidea

Bone remodeling is a process regulated by the interaction between cells and various molecules such as parathyroid hormone (PTH). The aim of the study was to evaluate the effect of different doses of PTH on osteoclast activity in a culture model of bone organs. Six-day-old male C57BL/6 mice (n=14) were euthanized and the calvariae were dissected and sectioned in the middle, keeping the periosteal and endosteal. The bone fragments were divided into three groups: Group I (control - without adding PTH), Group II (addition of 3 nM PTH) and Group III (30 nM PTH), all cultured in aMEM for up to 72 h osteoclast activity was evaluated by biochemical quantification of calcium released in the culture medium at intervals of 24, 48, and 72 h and by histomorphometric analysis of bone resorption lacunae at 72 h our results show that group II exhibited significantly higher values of calcium levels in the medium compared to group I (p<0.05) in all intervals, also being higher for group III at 24 hours (p<0.05). Group II promoted a greater demineralization area (22068 ± 2193 mm2) than those found in group I (2084 ± 38 mm2) and group III (8952 ± 246 mm2), with statistically significant difference (p<0.001) among all groups. We concluded that in culture model of bone organs PTH promotes higher bone resorption when administered in lower doses.

La remodelación ósea es un proceso regulado por la interacción entre las células y varias moléculas como la hormona paratiroidea (PTH). El objetivo de este estudio fue evaluar el efecto de diferentes dosis de PTH sobre la actividad de los osteoclastos en un modelo de cultivo de órganos óseos. Se sacrificaron ratones C57BL/6 machos, de 6 días de edad (n = 14), y se disecaron y seccionaron las calvarias, manteniendo el periostio y endostio. Los fragmentos óseos se dividieron en tres grupos: Grupo I (control - sin adición de PTH), Grupo II (adición de 3 mM de PTH) y Grupo III (30 nM de PTH), todos cultivados en aMEM hasta 72 horas. La actividad de los osteoclastos se evaluó mediante la cuantificación bioquímica de calcio liberado en medio de cultivo, a intervalos de 24, 48 y 72 horas, y por análisis histomorfométrico de las lagunas de resorción ósea a las 72 horas. Nuestros resultados muestran que el grupo II exhibió valores significativamente más altos de calcio en el medio, comparado con el grupo I (p <0.05) en todos los intervalos, siendo también más alto para el grupo III a las 24 horas (p <0.05). El grupo II promovió una mayor área de desmineralización (22068 ± 2193 mm2) que los encontrados en el grupo I (2084 ± 38 mm2) y en el grupo III (8952 ± 246 mm2), con diferencia estadísticamente significativa (p <0,001) entre todos los grupos. Concluimos que en el modelo de cultivo de órganos óseos la PTH promueve una mayor resorción ósea cuando se administra en dosis más bajas.

Effect of a cryopreservation protocol on the proliferation of stem cells from human exfoliated deciduous teeth.

OBJECTIVE: The aim of the present study was to evaluate the influence of a cryopreservation protocol on the proliferation and viability of stem cells from human exfoliated deciduous teeth (SHEDs). MATERIALS AND METHODS: Cells from the pulp of three deciduous teeth were isolated and characterized to confirm their stem cell nature. In second passage, part of the cells were submitted to normal conditions of cell culture (Control group), while part of the cells were maintained in 10% DMSO diluted in foetal bovine serum and submitted to the following cryopreservation protocol: 2 h at 4 °C, 18 h at -20 °C and then at -80 °C for two intervals (30 days - Cryopreservation I; and 180 days Cryopreservation II). Cell proliferation and cell cycle were evaluated at intervals of 24, 48 and 72 h after plating, and apoptosis-related events were analyzed at 72 h. RESULTS: All groups exhibited an increase in the number of cells, and no significant differences between the cryopreserved and control groups were observed (p > .05). The distribution of cells in the cell cycle phases was consistent with cell proliferation, and the percentage of viable cells was higher than 99% in all groups, indicating that cell viability was not affected by the cryopreservation protocol throughout the experiment. CONCLUSION: The proposed cryopreservation protocol is adequate for the storage of SHED, permitting their use in future experimental studies.

Fibroma gingival de células gigantes de tamaño inusual / Gingival giant cell fibroma of unusual size

Giant cell fibroma is a benign oral fibrous tumor and it is typically an asymptomatic sessile or pedunculated mass that is usually less than 1 cm in diameter. The lesion consists of uninflamed fibrous tissue in which there are numerous large uninucleated or multinucleated spindle- and stellate-shaped cells with prominent basophilic cytoplasm. The purpose of this paper is to report a case of a gingival giant cell fibroma of abnormal size. A 31-year-old white woman was referred to the dental service for evaluation of a growth on the mandibular gingival. The intraoral examination revealed a 3.0 × 1.5 cm exophytic gingival mass located in the lingual gingiva of the right mandibular permanent first and second molars. The differential diagnosis included peripheral ossifying fibroma, peripheral giant cell granuloma, and giant cell fibroma. Complete surgical excision of the lesion was performed and the diagnosis of giant cell fibroma was made. No complications or recurrence of the lesion have been noted after 4 years of follow-up. Although giant cell fibromas are benign lesions in which simple surgical excision is curative, it is very important that dental and medical professionals recognize it in light of the frequency of occurrence and the need for a precise diagnosis(AU)

El fibroma de células gigantes es un tumor fibroso benigno de la mucosa bucal que típicamente se presenta como una masa asintomática sésil o pediculada generalmente menos de 1 cm de diámetro. La lesión consiste en tejido fibroso no inflamado en el que se encuentran numerosas células fusiformes y estrelladas de gran tamaño, mononucleares o multinucleadas con prominente citoplasma basófilo. El propósito de este trabajo es describir el caso de un fibroma gingival de células gigantes de tamaño inusual. Una mujer blanca de 31 años de edad se presentó al servicio dental para la evaluación de un crecimiento en la encía mandibular. El examen clínico intrabucal reveló una masa gingival exofítica de 3,0 cm x 1,5 cm situado en la encía lingual en el área de los primeros y segundos molares permanentes mandibulares del lado derecho. El diagnóstico diferencial incluyó fibroma osificante periférico, granuloma periférico de células gigantes y fibroma de células gigantes. Se realizó la escisión quirúrgica completa de la lesión y el diagnóstico definitivo fue de fibroma de células gigantes. No se han observado complicaciones o recurrencia de la lesión después de 4 años de seguimiento. Aunque los fibromas de células gigantes son lesiones benignas en las que la escisión quirúrgica simple es curativa, es muy importante que los profesionales dentales y médicos reconozcan la necesidad de un diagnóstico preciso en vista de la frecuencia de aparición(AU)

Effect of low-level laser irradiation on proliferation and viability of human dental pulp stem cells.

A positive effect of low-level laser irradiation (LLLI) on the proliferation of some cell types has been observed, but little is known about its effect on dental pulp stem cells (DPSCs). The aim of this study was to identify the lowest energy density able to promote the proliferation of DPSCs and to maintain cell viability. Human DPSCs were isolated from two healthy third molars. In the third passage, the cells were irradiated or not (control) with an InGaAlP diode laser at 0 and 48 h using two different energy densities (0.5 and 1.0 J/cm²). Cell proliferation and viability and mitochondrial activity were evaluated at intervals of 24, 48, 72, and 96 h after the first laser application. Apoptosis- and cell cycle-related events were analyzed by flow cytometry. The group irradiated with an energy density of 1.0 J/cm² exhibited an increase of cell proliferation, with a statistically significant difference (p < 0.05) compared to the control group at 72 and 96 h. No significant changes in cell viability were observed throughout the experiment. The distribution of cells in the cell cycle phases was consistent with proliferating cells in all three groups. We concluded that LLLI, particularly a dose of 1.0 J/cm², contributed to the growth of DPSCs and maintenance of its viability. This fact indicates this therapy to be an important future tool for tissue engineering and regenerative medicine involving stem cells.

Effect of low-level laser therapy on mesenchymal stem cell proliferation: a systematic review.

Low-level laser therapy (LLLT) has been used in several in vitro experiments in order to stimulate cell proliferation. Cells such as fibroblasts, keratinocytes, lymphocytes, and osteoblasts have shown increased proliferation when submitted to laser irradiation, although little is known about the effects of LLLT on stem cells. This study aims to assess, through a systematic literature review, the effects of LLLT on the in vitro proliferation of mesenchymal stem cells. Using six different terms, we conducted an electronic search in PubMed/Medline database for articles published in the last twelve years. From 463 references obtained, only 19 papers met the search criteria and were included in this review. The analysis of the papers showed a concentration of experiments using LLLT on stem cells derived from bone marrow, dental pulp, periodontal ligament, and adipose tissue. Several protocols were used to irradiate the cells, with variations on wavelength, power density, radiation time, and state of light polarization. Most studies demonstrated an increase in the proliferation rate of the irradiated cells. It can be concluded that the laser therapy positively influences the in vitro proliferation of stem cells studied, being necessary to carry out further experiments on other cell types and to uniform the methodological designs.

Effects of laser therapy on the proliferation of human periodontal ligament stem cells.

Low-level laser irradiation (LLLI) stimulates the proliferation of a variety of cell types. However, very little is known about the effect of laser therapy on dental stem cells. The aim of the present study was to evaluate the effect of LLLI (660 nm, 30 mW) on the proliferation rate of human periodontal ligament stem cells (hPDLSC), obtained from two healthy permanent third molars extracted due to surgical indication. Culture cells were either irradiated or not (control) with an InGaAIP diode laser at 0 and 48 h, using two different energy densities (0.5 J/cm², 16 s and 1.0 J/cm², 33 s). Cell proliferation was evaluated by the Trypan blue exclusion method and by measuring mitochondrial activity using the MTT-based cytotoxicity assay at intervals of 0, 24, 48, and 72 h after the first laser application. An energy density of 1.0 J/cm² improved the cell proliferation in comparison to the other groups (control and laser 0.5 J/cm²) at 48 and 72 h. The group irradiated with 1.0 J/cm² presented significantly higher MTT activity at 48 and 72 h when compared to the energy density of 0.5 J/cm². It can be concluded that LLLI using infrared light and an energy density of 1.0 J/cm² has a positive stimulatory effect on the proliferation of hPDLSC.

Low-level laser irradiation induces in vitro proliferation of mesenchymal stem cells.

OBJECTIVE: To evaluate the effect of low-level laser irradiation on the proliferation and possible nuclear morphological changes of mouse mesenchymal stem cells. METHODS: Mesenchymal stem cells derived from bone marrow and adipose tissue were submitted to two applications (T0 and T48 hours) of low-level laser irradiation (660 nm; doses of 0.5 and 1.0 J/cm2). The trypan blue assay was used to evaluate cell viability, and growth curves were used to analyze proliferation at zero, 24, 48, and 72 hours. Nuclear alterations were evaluated by staining with DAPI (4'-6-diamidino-2-phenylindole) at 72 hours. RESULTS: Bone marrow-derived mesenchymal stem cells responded to laser therapy in a dose-dependent manner. Higher cell growth was observed when the cells were irradiated with a dose of 1.0 J/cm2, especially after 24 hours (p<0.01). Adipose-derived mesenchymal stem cells responded better to a dose of 1.0 J/cm2, but higher cell proliferation was observed after 48 hours (p<0.05) and 72 hours (p<0.01). Neither nuclear alterations nor a significant change in cell viability was detected in the studied groups. CONCLUSION: Low-level laser irradiation stimulated the proliferation of mouse mesenchymal stem cells without causing nuclear alterations. The biostimulation of mesenchymal stem cells using laser therapy might be an important tool for regenerative therapy and tissue engineering.

Low-level laser irradiation induces in vitro proliferation of mesenchymal stem cells / Laser de baixa intensidade induz à proliferação in vitro de células-tronco mesenquimais

Objective : To evaluate the effect of low-level laser irradiation on the proliferation and possible nuclear morphological changes of mouse mesenchymal stem cells. Methods : Mesenchymal stem cells derived from bone marrow and adipose tissue were submitted to two applications (T0 and T48 hours) of low-level laser irradiation (660nm; doses of 0.5 and 1.0J/cm2). The trypan blue assay was used to evaluate cell viability, and growth curves were used to analyze proliferation at zero, 24, 48, and 72 hours. Nuclear alterations were evaluated by staining with DAPI (4’-6-diamidino-2-phenylindole) at 72 hours. Results : Bone marrow-derived mesenchymal stem cells responded to laser therapy in a dose-dependent manner. Higher cell growth was observed when the cells were irradiated with a dose of 1.0J/cm2, especially after 24 hours (p<0.01). Adipose-derived mesenchymal stem cells responded better to a dose of 1.0J/cm2, but higher cell proliferation was observed after 48 hours (p<0.05) and 72 hours (p<0.01). Neither nuclear alterations nor a significant change in cell viability was detected in the studied groups. Conclusion : Low-level laser irradiation stimulated the proliferation of mouse mesenchymal stem cells without causing nuclear alterations. The biostimulation of mesenchymal stem cells using laser therapy might be an important tool for regenerative therapy and tissue engineering. .

Objetivo : Avaliar o efeito da terapia com laser de baixa intensidade sobre a proliferação e as possíveis alterações morfológicas nucleares em células-tronco mesenquimais de camundongos. Métodos : Células-tronco mesenquimais derivadas da medula óssea e do tecido adiposo foram submetidas a duas aplicações (T0 e T48 horas) de laser de baixa intensidade (660nm; doses de 0,5 e 1,0J/cm2). O ensaio de azul de tripan foi utilizado para a avaliação da viabilidade celular, e curvas de crescimento foram usadas para avaliar a proliferação das células em zero, 24, 48, e 72 horas. Alterações nucleares foram avaliadas por coloração com DAPI (4-6-diamidino-2-fenilindolo) em 72 horas. Resultados : As células-tronco mesenquimais derivadas da medula óssea responderam a terapia com laser de forma dose-dependente. Um maior crescimento celular foi observado quando as células foram irradiadas com dose de 1,0J/cm2, especialmente depois de 24 horas (p<0,01). As células-tronco mesenquimais derivadas do tecido adiposo responderam melhor à dose de 1,0J/cm2, com maior proliferação após 48 (p<0,05) e 72 horas (p<0,01). Nem alterações nucleares nem a mudança significativa na viabilidade celular foi detectada nos grupos estudados. Conclusão : Laser de baixa intensidade estimulou a proliferação de células-tronco mesenquimais sem causar alterações nucleares. A bioestimulação de células-tronco mesenquimais por laserterapia pode ser uma ferramenta importante para a terapia regenerativa e a engenharia tecidual. .

Cell adhesion in bone grafts associated to nanotechnology: a systematic review

Introduction: Tissue engineering aims at the development of biological substitutes that can restore, maintain, or improve the functionality of damaged tissue or organs. To this end, molecular and cellular interactions may influence the tissue reactions to biomaterials. In order to be effective and integrated to the receiving area, the bone graft is required to allow a strong cell adhesion, interacting with several molecules to induce migration, differentiation, and thus the mineralization of the new bone on the graft. These cell adhesion molecules (CAM) will mediate the contact between two cells or between cells and the extracellular matrix, an essential process to the success of the implant. Objective: This paper is a systematic review of the literature on the mechanisms of cell adhesion to bone grafts associated to nanotechnology, describing the importance and the role of those molecules in the adhesion and thus in tissue regeneration. Literature review: After the use of search strategies, 18 articles that describe processes of cell adhesion to bone grafts were selected. Results: The main reported mechanisms involve cell adhesion molecules (CAMs) and extracellular matrix components. Conclusion: Several molecules are involved in the process of cell adhesion to bone grafts, highlighting the role of integrins, the focal adhesion mechanism, the influence of the collagen matrix, and the activity of alkaline phosphatase in bone matrix formation. Accurate identification of these mechanisms of cell adhesion is essential for further advancement in tissue engineering, such as the production of biological bone substitutes that achieve a better clinical outcome.

Low-level laser therapy promotes proliferation and invasion of oral squamous cell carcinoma cells.

Low-level laser therapy (LLLT) has been shown to be effective in promoting cell proliferation. There is speculation that the biostimulatory effect of LLLT causes undesirable enhancement of tumor growth in neoplastic diseases since malignant cells are more susceptible to proliferative stimuli. This study evaluated the effects of LLLT on proliferation, invasion, and expression of cyclin D1, E-cadherin, ß-catenin, and MMP-9 in a tongue squamous carcinoma cell line (SCC25). Cells were irradiated with a diode laser (660 nm) using two energy densities (0.5 and 1.0 J/cm(2)). The proliferative potential was assessed by cell growth curves and cell cycle analysis, whereas the invasion of cells was evaluated using a Matrigel cell invasion assay. Expression of cyclin D1, E-cadherin, ß-catenin, and MMP-9 was analyzed by immunofluorescence and flow cytometry and associated with the biological activities studied. LLLT induced significantly the proliferation of SCC25 cells at 1.0 J/cm(2), which was accomplished by an increase in the expression of cyclin D1 and nuclear ß-catenin. At 1.0 J/cm(2), LLLT significantly reduced E-cadherin and induced MMP-9 expression, promoting SCC25 invasion. The results of this study demonstrated that LLLT exerts a stimulatory effect on proliferation and invasion of SCC25 cells, which was associated with alterations on expression of proteins studied.

Oral angioleiomyoma: a case report and considerations on differential diagnosis / Angioleiomioma oral: relato de caso e considerações no diagnóstico diferencial

Angioleiomyomas are benign mesenchymal tumors derived from smooth muscle, which rarely occur in the oral cavity. We report a case of an angioleiomyoma occurring in the maxillary gingiva. The lesion was painless, with a lobulated surface, fibrous in consistency, and firm upon palpation. Microscopic examination showed an encapsulated tumor mass composed of large vascular channels of varying calibers, surrounded by thick walls of irregularly arranged, spindle-shaped cells, which were immunopositive for smooth-muscle actin. It is sometimes difficult to differentiate an angioleiomyoma from other spindle-cell tumors, thus we emphasize its histological differential diagnosis.

Angioleiomiomas são tumores mesenquimais benignos derivados de músculo liso que raramente ocorrem na cavidade oral. Relatamos um caso de angioleiomioma na gengiva maxilar. A lesão era indolor, com superfície lobulada, consistência fibrosa e firme à palpação. O exame histológico mostrou massa tumoral encapsulada, composta por grandes canais vasculares de diferentes calibres, circundados por paredes espessas de células fusiformes dispostas de forma irregular, as quais se apresentavam imunopositivas para actina de músculo liso. A distinção entre angioleiomioma e outros tumores de células fusiformes algumas vezes é difícil e, por essa razão, enfatizamos seu diagnóstico diferencial histológico.

Proliferation of human periodontal ligament mesenchymal cells on polished and plasma nitriding titanium surfaces

Aim: To evaluate the proliferative capacity of mesenchymal cells derived from human periodontalligament on polished and plasma-treated titanium surfaces. Methods: Eighteen titanium disks werepolished and half of them (n=9) were submitted to plasma nitriding using the cathodic cage technique.Mesenchymal cells were isolated from periodontal ligament of impacted third molars (n=2) andcultured on titanium disks (polished and nitrided) and on a plastic surface as a positive control of cellproliferation. Cell proliferation was analyzed and growth curves were constructed for the differentgroups by determining the number of cells adhered to the different surfaces at 24, 48 and 72 h afterplating. Results: Higher cell number was observed for the nitrided surface at 24 and 48 h.However, no statistically significant difference in cell proliferation was observed between the twodifferent surface treatments (p>0.05). Conclusions: We concluded that plasma nitriding producedsurfaces that permitted the proliferation of human periodontal ligament mesenchymal cells. Associatedto other physical and chemical properties, it is possible to assume the feasibility of plasma nitridingmethod and its positive effect on the early cellular events of osseointegration.

Rendimento de células, esenquimais do tecido adiposo submetidas a diferentes protocolos de extração / Adipose-derived mesenchymal cells yield under different cell extraction protocols

Objetivo: Estabelecer um protocolo de extração de células mesenquimais do tecido adiposo, a partir da avaliação do rendimento celular em dois métodos de digestão enzimática do tecido. Material e Métodos: Fragmentos de tecido adiposo foram extraídos da região inguinal de camundongos e processados por dois protocolos distintos: Grupo 1 – digestão enzimática com colagenase I; Grupo 2 – digestão enzimática com colagenas e I e tripsina/EDTA, ambos por 1 hora a 37°C.No terceiro subcultivo (P3) as células dos dois grupos foram submetidas a contagem em Câmara de Neubauer para avaliação da proliferação celular e obtenção da curva decrescimento nos intervalos de 24, 48 e 72 horas. Foi realizada a marcação pelo DAPI no intervalo de 72 horas, nos grupos estudados, para avaliar a existência de danos morfológicos nucleares. Os dados foram analisados estatisticamente, com nível de significância de 5%. Resultados: Os dois grupos exibiram um padrão de crescimento celular ascendente. As médias das contagens celulares demonstraram uma maior proliferação celular no grupo I, com diferença estatisticamente significante entre os grupos nos intervalos de 48 e72 horas (p<0,05). Alterações morfológicas nucleares não oram observadas nos grupos. Conclusão: A digestão enzimática do tecido adiposo por colagenase I, sem associação com a tripsina, proporcionou melhor rendimento das células mesenquimais, o que favorece a escolha desse protocolo em experimentos com este tipo celular.

Objective: To establish a protocol for extraction of adipose derivedmesenchymal cells, evaluating the cell yield in twomethods of tissue enzymatic digestion. Material and Methods:Fragments of adipose tissue were removed from the inguinal region of mice and processed by two different protocols:Group 1 - enzymatic digestion with collagenase I; Group 2 -enzymatic digestion with collagenase I and trypsin/EDTA,both for 1 hour at 37°C. In the third passage (P3), cells fromboth groups were counted in a Neubauer chamber forevaluation of cell proliferation, and growth curves were plottedat intervals of 24, 48 and 72 hours. The DAPI nuclear stainingwas performed in both groups in a 72-hour interval to evaluatethe presence of nuclear morphological damage. Data wereanalyzed statistically with a significance level of 5%. Results:The two groups showed an upward pattern of cell growth.The mean cell counts showed a higher cell proliferation ingroup I, with a statistically significant difference betweengroups in intervals of 48 and 72 hours (p<0.05). Nuclearmorphological changes were not observed in the groups.Conclusion: The enzymatic digestion of adipose tissue bycollagenase I, without association with trypsin, improves theyield of mesenchymal cells, what suggests the choice ofthat protocol in experiments with this cell type.

Rendimento de células mesenquimais do ligamento periodontal humano submetidas a diferentes protocolos de criopreservação / Yield of human periodontal ligament mesenchymal cells under different protocols of cryopreservation

Introdução: A técnica de criopreservação tem como característica cessar reversivelmente todas as funções biológicas dos tecidos vivos em baixas temperaturas e tem sido aplicada a diversas células humanas, visando à sua utilização posterior. Objetivo: Avaliar a proliferação de células mesenquimais do ligamento periodontal humano após a criopreservação por dois diferentes protocolos. Método: As células do ligamento periodontal foram obtidas a partir de dois dentes (terceiros molares) hígidos, com indicação de remoção cirúrgica. Após o processamento, as células foram cultivadas em placas de Petri e mantidas a 37 °C em 5% de CO2, até atingirem 70-90% de confluência, com troca de meio a cada três dias. Na primeira passagem, as células foram divididas em dois grupos e criopreservadas: Grupo -80 °C - criopreservação em ultrafreezer por 45 dias; Grupo -196 °C - criopreservação em nitrogênio líquido por 45 dias. Decorrido esse tempo, as células dos dois grupos foram descongeladas e plaqueadas para o experimento. A curva de crescimento dos grupos estudados foi traçada a partir de contagem em Câmara de Neubauer e pelo método de ensaio do MTT, nos intervalos de 24, 48 e 72 horas. Os resultados foram analisados por meio do teste de Mann-Whitney, com nível de significância de 5%. Resultado: Verificou-se um crescimento ascendente nos dois protocolos utilizados, porém uma maior taxa proliferativa foi verificada no grupo criopreservado em nitrogênio líquido (p < 0,05). Conclusão: Ambos os protocolos de criopreservação estudados foram eficazes, porém a criopreservação em nitrogênio líquido (-196 °C) manteve uma maior taxa de proliferação celular em todos os intervalos de tempo.

Introduction: Cryopreservation aims to stop reversibly the biological functions of living tissues at low temperatures, and is an important resource for the storage of human cells for later use. Aim: To assess the proliferation of mesenchymal cells from human periodontal ligament cryopreserved by two different protocols. Method: Periodontal ligament cells were obtained from third molars with an indication for surgical removal. After processing, cells were grown and maintained at 37 °C in 5% CO2 until they reached 70-90% confluency, with medium changing every three days. In the first passage cells were divided into two groups, according to the protocol used: Group -80 °C - cryopreserved in ultrafreezer for 45 days, Group -196 °C - cryopreserved in liquid nitrogen for 45 days. After this time, cells from both groups were thawed and plated for the experiment. The growth curve of the groups was drawn from counting cells in a Neubauer chamber and by the MTT assay method, in the intervals of 24, 48 and 72 hours. The data were analyzed using the Mann-Whitney test with a significance level of 5%. Result: There was an upward cell growth in both protocols used, but a higher proliferative rate was observed in group cryopreserved in liquid nitrogen (p < 0.05). Conclusion: Cryopreservation has proven to be an effective technique for the storage and of mesenchymal cells from the periodontal ligament, especially when stored at a temperature of -196 °C.

Use of Clinical Cases in a Virtual Learning Environment as an Approach to Teaching Human Embryology / Uso de Casos Clínicos en Ambiente Virtual como Estrategia de Enseñanza de la Embriología Humana

The objective of this study was to evaluate the effectiveness of virtual learning as an approach to teaching human embryology. For this purpose, clinical cases comprising the six major topics of human embryology were organized into a blog in order to complement the content discussed in the classroom. Scientific articles were made available to reinforce theoretical contents and ethical-humanistic issues were addressed in discussion forums. The mean grades of the students at the end of the semester were compared with those of the previous semester when the method had not been applied. Student perceptions of blog effectiveness were evaluated using an electronic questionnaire. A substantial increase in mean grades was observed compared to the previous class. Analysis of the questionnaires showed that the students considered the blog to be a practical and useful learning tool. In conclusion, the use of clinical cases in a virtual learning environment is an effective tool to teach human embryology.

El objetivo del trabajo fue evaluar la eficacia de un método de enseñanza de la Embriología en ambiente virtual. Para complementar el contenido discutido en clases, fueron organizados en un blog, casos clínicos abordando seis ejes temáticos de Embriología Humana. Artículos científicos estuvieron disponibles para consolidación de los contenidos teóricos y el eje ético-humanístico fue abordado en foros de discusión. Al final del semestre la media de las notas de los alumnos fue comparada con la media de un semestre anterior donde la metodología no fue utilizada. La percepción de los alumnos con relación a la eficacia del uso del blog en el aprendizaje fue evaluada a través de un cuestionario electrónico. Se observó aumento considerable de la media de las notas al ser comparadas con las notas del período lectivo anterior. El análisis de los cuestionarios reveló que los alumnos consideraron el blog como un instrumento práctico y útil de aprendizaje. Se concluye que esta metodología representó una herramienta eficiente em la enseñanza de los contenidos de Embriología Humana.

Influência de um protocolo de criopreservação no rendimento in vitro de células-tronco derivadas do tecido adiposo / Effect of a cryopreservation protocol on the in vitro yield of adipose-derived stem cells

INTRODUÇÃO: O tecido adiposo obtido por lipoaspiração pode ser uma fonte acessível de células-tronco, para posterior aplicação clínica na regeneração tecidual. O processo de criopreservação mantém essas células vivas por longos períodos, sem prejuízo a suas funções. O objetivo deste estudo foi avaliar a influência de um protocolo de criopreservação na proliferação das células-tronco derivadas do tecido adiposo. MÉTODO: Fragmentos de tecido adiposo de camundongos foram submetidos a digestão enzimática e as células foram cultivadas em meio α-MEM (do inglês Minimum Essential Medium), suplementado com 10% de soro fetal bovino (SFB), e mantidas a 37ºC em 5% de dióxido de carbono. No primeiro subcultivo, uma alíquota de 1x10(6) células foi criopreservada em SFB com 10% de dimetilsulfóxido por 30 dias, e outro grupo permaneceu em cultura. No terceiro subcultivo, as células dos dois grupos (não-criopreservadas e criopreservadas) foram plaqueadas e a viabilidade celular e as curvas de crescimento foram estabelecidas a partir de contagem em hemocitômetro e pelo ensaio de MTT, nos intervalos de 24 horas, 48 horas e 72 horas. A avaliação da morfologia nuclear foi realizada pela marcação por DAPI. Os dados foram analisados estatisticamente, com nível de significância de 5%. RESULTADOS: Observou-se padrão de crescimento celular ascendente em ambos os grupos, sem diferença significante ao longo do experimento (P > 0,05). Não houve alteração considerável da viabilidade celular e danos nucleares também não foram observados nos grupos estudados. CONCLUSÕES: O protocolo de criopreservação avaliado mostrou-se eficaz para manter a integridade das células-tronco de tecido adiposo, permitindo seu armazenamento para uso posterior.

BACKGROUND: Adipose tissue obtained by liposuction may be an accessible source of stem cells for future clinical application in tissue regeneration. Cryopreservation maintains stem cells in a live state for long periods of time, without impairing their function. The aim of this study was to assess the effect of a cryopreservation protocol on the proliferation of adipose-derived stem cells. METHODS: Fragments of mouse adipose tissue were subjected to enzymatic digestion in order to isolate cells that were then cultured in minimum essential medium (α-MEM) supplemented with 10% fetal bovine serum (FBS). Cells were maintained at 37°C in 5% carbon dioxide (CO2). At the first passage, an aliquot of 1 × 10(6) cells was cryopreserved in FBS with 10% dimethylsulfoxide (DMSO) for 30 days, whereas the remaining cells were seeded and maintained in culture. When these cells reached the third passage, the 2 groups of cells (cryopreserved and non-cryopreserved) were seeded for experiments. Cell viability and proliferation curves were established at intervals of 24, 48, and 72 hours by counting cells with a hemocytometer and MTT assay. Nuclear morphology was assessed by DAPI staining. The data were statistically analyzed, with a significance level of 5%. RESULTS: Increasing cellular proliferation was observed in both groups, with no significant difference throughout the experiment (P > 0.05). There was no significant change in cell viability and signs of nuclear damage were not detected in both the groups studied. CONCLUSIONS: The cryopreservation protocol analyzed was effective for maintaining the integrity of adipose-derived stem cells, allowing their storage for later use.