RESUMEN

A screening system for early-stage oral cancer and precancerous lesions should be established because it is difficult to detect them even for specialists and they are often detected too late. In this paper, we propose a method for automatically classifying fluorescence images acquired by ALA-PDD (Photodynamic Diagnosis using 5-Aminolevulinic Acid) into three classes: Normal, Low-Risk, High-Risk. We augment a small image dataset by training GAN (Generative adversarial networks) with Differentiable Augmentation, and then train CNN (Convolutional Neural Network) for the classification by the augmented dataset. Experimental results show good classification results, which suggest that the combination of ALA-PDD and CNN classification is a promising method for oral cancer screening. Clinical Relevance- The method proposed in this paper has a potential to be used as a screening method for early-stage oral cancer and precancerous lesions, that is non-invasive, accurate, easy to use, and does not require specialization.

Asunto(s)

Neoplasias de la Boca , Lesiones Precancerosas , Detección Precoz del Cáncer , Humanos , Neoplasias de la Boca/diagnóstico , Redes Neurales de la Computación , Lesiones Precancerosas/diagnóstico

RESUMEN

Detecting early-stage oral cancer and precancerous lesions are critical to improving patient prognosis and quality of life after treatment. Photodynamic diagnosis using 5-aminolevulinic acid enables the detection of malignant lesions. This study aimed to improve the diagnostic accuracy of photodynamic diagnosis using an objective chromaticity analysis of fluorescence emitted from oral lesions. Sixty-seven patients with clinically suspicious oral cavity lesions underwent photodynamic diagnosis after topical application of 5-aminolevulinic acid solution, followed by imaging and histological evaluation of the lesions. Chromaticity red and green values were measured from the fluorescence images on the lesion, and the red-to-green ratio was calculated. The photodynamic diagnosis allowed for the visualization of oral cancer and high-risk dysplasia as red fluorescence. Compared to low-risk dysplasia and benign lesions, oral cancer and high-risk dysplasia areas had a significantly higher red value and red-to-green ratio. After setting the cutoff value, sensitivity and specificity were 83.3-88.7% and 83.3-83.9%, respectively, when discriminating between oral cancer or high-risk dysplasia and low-risk dysplasia or benign lesions. Photodynamic diagnosis combined with chromaticity analysis may be a valuable diagnostic tool for detecting oral lesions, with a high likelihood of malignant transformation.

RESUMEN

We investigated whether irradiation with 405-nm blue LED light could inhibit the growth of not only single- but dual-species biofilms formed by Candida albicans and Streptococcus mutans on denture base resin and cause the alteration in gene expression related to adhesion and biofilm formation. C. albicans and S. mutans single-/dual-species biofilms were formed on the denture base specimens. The biofilms were irradiated with 405-nm blue LED light (power density output: 280 mW/cm2) for 0 (control) and 40 min. Dual-species biofilms were analyzed using CFU assay and fluorescence microscopy, and single-/dual-species biofilms were analyzed using alamarBlue assays and gene expression analysis. To assess the inhibitory effect of irradiation on dual-species biofilms, specimens after irradiation were aerobically incubated for 12 h. After incubation, the inhibition of growth was assessed using CFU assays and fluorescence microscopy. Data were analyzed using the Mann-Whitney U or Student's t test (p < 0.05). Irradiation produced a significant inhibitory effect on biofilms. Fluorescence microscopy revealed that almost all C. albicans and S. mutans cells were killed by irradiation, and there was no notable difference in biofilm thickness immediately after irradiation and after irradiation and incubation for 12 h. alamarBlue assays indicated the growth of the biofilms was inhibited for 12-13 h. The expression of genes associated with adhesion and biofilm formation-als1 in C. albicans and ftf, gtfC, and gtfB in S. mutans-significantly reduced by irradiation. Irradiation with 405-nm blue LED light effectively inhibited the growth of C. albicans and S. mutans dual-species biofilms for 12 h.

Asunto(s)

Candida albicans , Streptococcus mutans , Biopelículas , Bases para Dentadura , Humanos , Luz , Streptococcus mutans/genética

RESUMEN

This study investigated: (1) the microbicidal effect of 405-nm blue LED light irradiation on biofilm formed by Candida albicans hyphae and Streptococcus mutans under dual-species condition on denture base resin, (2) the generation of intracellular reactive oxygen species (ROS) induced by irradiation, and (3) the existence of intracellular porphyrins, which act as a photosensitizer. Denture base resin specimens were prepared and C. albicans and S. mutans dual-species biofilms were allowed to form on the specimens. The biofilms were irradiated with 405-nm blue LED light and analyzed using the colony-forming unit assay, fluorescence microscopy, and scanning electron microscopy (SEM). Single-species biofilms of C. albicans and S. mutans formed on the specimens were irradiated with 405-nm blue LED light. After the irradiation, the intracellular ROS levels in C. albicans and S. mutans cells were measured. In addition, the level of intracellular porphyrins in C. albicans and S. mutans were measured. Irradiation for more than 30 min significantly inhibited the colony formation ability of C. albicans and S. mutans. Fluorescence microscopy revealed that almost all C. albicans and S. mutans cells were killed by irradiation. SEM images showed various cell damage patterns. Irradiation led to the generation of intracellular ROS and porphyrins were present in both C. albicans and S. mutans cells. In conclusion, irradiation with 405-nm blue light-emitting diode light for 40 min effectively disinfect C. albicans hyphae and S. mutans dual-species biofilms and possibly react with intracellular porphyrins resulting in generation of ROS in each microorganism.

Asunto(s)

Candida albicans , Streptococcus mutans , Biopelículas , Bases para Dentadura , Fármacos Fotosensibilizantes/farmacología

RESUMEN

Considering that every tissue/organ has the most suitable microenvironment for its functional cells, controlling induced pluripotent stem cell (iPSC) differentiation by culture on frozen sections having a suitable microenvironment is possible. Induced PSCs were cultured on frozen sections of the liver, the brain, the spinal cord, and cover glasses (control) for 9 days. The iPSCs cultured on the sections of the liver resembled hepatocytes, whereas those on sections of the brain and the spinal cord resembled neuronal cells. The percentage of hepatocytic marker-positive cells in the iPSCs cultured on the sections of the liver was statistically higher than that of those in the iPSCs cultured on the sections of the brain and the spinal cord or on cover glasses. In contrast, the iPSCs cultured on the sections of the brain and the spinal cord revealed a high percentage of neural marker-positive cells. Thus, iPSCs can be differentiated into a specific cell lineage in response to specific factors within frozen sections of tissues/organs. Differentiation efficacy of the frozen sections markedly differed between the iPSC clones. Therefore, our induction method could be simple and effective for evaluating the iPSC quality.

Asunto(s)

Diferenciación Celular , Secciones por Congelación/métodos , Células Madre Pluripotentes Inducidas/citología , Animales , Biomarcadores/metabolismo , Células Cultivadas , Hepatocitos/citología , Hepatocitos/metabolismo , Humanos , Masculino , Ratones Endogámicos ICR

RESUMEN

Oral health promotion and examinations have contributed to the early detection of oral cancer and oral potentially malignant disorders, leading to the adaptation of minimally invasive therapies and subsequent improvements in the prognosis/maintenance of the quality of life after treatments. However, the accurate detection of early-stage oral cancer and oral epithelial dysplasia is particularly difficult for conventional oral examinations because these lesions sometimes resemble benign lesions or healthy oral mucosa tissues. Although oral biopsy has been considered the gold standard for accurate diagnosis, it is deemed invasive for patients. For this reason, most clinicians are looking forward to the development of non-invasive diagnostic technologies to detect and distinguish between cancerous and benign lesions. To date, several non-invasive adjunctive fluorescence-based detection systems have improved the accuracy of the detection and diagnosis of oral mucosal lesions. Autofluorescence-based systems can detect lesions as a loss of autofluorescence through irradiation with blue-violet lights. Photodynamic diagnosis using 5-aminolevulinic acid (ALA-PDD) shows the presence of very early oral cancers and oral epithelial dysplasia as a red fluorescent area. In this article, currently used fluorescence-based diagnostic methods are introduced and discussed from a clinical point of view.

RESUMEN

This study aimed to investigate the cleansing effects of grapefruit seed extract (GSE) on biofilms of Candida albicans (C. albicans) formed on denture-base resin and the influence of GSE on the mechanical and surface characteristics of the resin. GSE solution diluted with distilled water to 0.1% (0.1% GSE) and 1% (1% GSE) and solutions with Polident® denture cleansing tablet dissolved in distilled water (Polident) or in 0.1% GSE solution (0.1% G+P) were prepared as cleansing solutions. Discs of acrylic resin were prepared, and the biofilm of C. albicans was formed on the discs. The discs with the biofilm were treated with each solution for 5 min at 25°C. After the treatment, the biofilm on the discs was analyzed using a colony forming unit (CFU) assay, fluorescence microscopy, and scanning electron microscopy (SEM). In order to assess the persistent cleansing effect, the discs treated with each solution for 5 min were aerobically incubated in Yeast Nitrogen Base medium for another 24 h. After incubation, the persistent effect was assessed by CFU assay. Some specimens of acrylic resin were immersed in each solution for 7 days, and changes in surface roughness (Ra), Vickers hardness (VH), flexural strength (FS), and flexural modulus (FM) were evaluated. As a result, the treatment with 1% GSE for 5 min almost completely eliminated the biofilm formed on the resin; whereas, the treatment with 0.1% GSE, Polident, and 0.1% G+P for 5 min showed a statistically significant inhibitory effect on biofilms. In addition, 0.1% GSE and 0.1% G+P exerted a persistent inhibitory effect on biofilms. Fluorescence microscopy indicated that Polident mainly induced the death of yeast, while the cleansing solutions containing at least 0.1% GSE induced the death of hyphae as well as yeast. SEM also revealed that Polident caused wrinkles, shrinkage, and some deep craters predominantly on the cell surfaces of yeast, while the solutions containing at least 0.1% GSE induced wrinkles, shrinkage, and some damage on cell surfaces of not only yeasts but also hyphae. No significant changes in Ra, VH, FS, or FM were observed after immersion in any of the solutions. Taken together, GSE solution is capable of cleansing C. albicans biofilms on denture-base resin and has a persistent inhibitory effect on biofilm development, without any deteriorations of resin surface.

Asunto(s)

Biopelículas/efectos de los fármacos , Candida albicans/fisiología , Citrus paradisi/química , Extractos Vegetales/farmacología , Polimetil Metacrilato , Resinas Sintéticas , Semillas/química , Biopelículas/crecimiento & desarrollo , Humanos , Extractos Vegetales/química

RESUMEN

This study investigated (i) the degradation effect of 405-nm blue light-emitting diode (LED) light irradiation on Candida albicans and C. glabrata biofilms formed on denture base resin and (ii) the effects of 405-nm blue LED light irradiation on the mechanical and surface characteristics of the resin. Polymethyl methacrylate denture base resin discs were prepared, and C. albicans or C. glabrata biofilms formed on the denture base resin discs. Each biofilm was irradiated with 405-nm blue LED light under a constant output power (280 mW/cm2) for different times in a moisture chamber with 100% relative humidity. Postirradiation, each biofilm was analyzed using a colony-forming unit assay, fluorescence microscopy, and scanning electron microscopy (SEM). Parallelepiped specimens of acrylic resin were prepared, and changes in their flexural strength (FS), flexural modulus (FM), and surface roughness (Ra) preirradiation and postirradiation with 405-nm blue LED light were evaluated. Irradiation for 30 min completely inhibited colony formation in both Candida species. Fluorescence microscopy showed that almost all Candida cells were killed because of irradiation. SEM images showed various cell damage patterns, such as wrinkles, shrinkage, and cell surface damage. An increase in FS was noted postirradiation, but no significant changes were observed in FM and Ra preirradiation and postirradiation. In conclusion, irradiation with 405-nm blue LED light induces degradation of C. albicans and C. glabrata biofilms on denture base resin, even in the absence of photosensitizers, without resin surface deterioration.

Asunto(s)

Resinas Acrílicas/farmacología , Biopelículas/efectos de los fármacos , Candida/efectos de los fármacos , Bases para Dentadura , Luz , Polimetil Metacrilato/farmacología , Candida/ultraestructura , Candida albicans/efectos de los fármacos , Candida albicans/ultraestructura , Candida glabrata/efectos de los fármacos , Candida glabrata/ultraestructura , Recuento de Colonia Microbiana , Fármacos Fotosensibilizantes/farmacología , Propiedades de Superficie

RESUMEN

Dental pulp stem cells (DPSCs) are an attractive cell source for use in cell-based therapy, regenerative medicine, and tissue engineering because DPSCs have a high cell proliferation ability and multidifferentiation capacity. However, several problems are associated with the collection and preservation of DPSCs for use in future cell-based therapy. In particular, the isolation of DPSCs for cryopreservation is time consuming and expensive. In this study, we developed a novel cryopreservation method (NCM) for dental pulp tissues to isolate suitable DPSCs after thawing cryopreserved tissue. Using the NCM, dental pulp tissues were cultured on adhesion culture dishes for 5 days and then cryopreserved. After thawing, the cryopreserved dental pulp tissue fragments exhibited cell migration. We evaluated each property of DPSCs isolated using the NCM (DPSCs-NCM) and the explant method alone without cryopreservation (DPSCs-C). DPSCs-NCM had the same proliferation capacity as DPSCs-C. Flow cytometry (FACS) analysis indicated that both DPSCs-NCM and DPSCs-C were positive for mesenchymal stem cell markers at the same level but negative for hematopoietic cell markers. Moreover, both DPSCs-NCM and DPSCs-C could differentiate into osteogenic, chondrogenic, and adipogenic cells during culture in each induction medium. These results suggest that DPSCs-NCM may be mesenchymal stem cells. Therefore, our novel method might facilitate the less expensive cryopreservation of DPSCs, thereby providing suitable DPSCs for use in patients in future cell-based therapies.

Asunto(s)

Diferenciación Celular , Separación Celular/métodos , Criopreservación/métodos , Pulpa Dental/citología , Células Madre/citología , Adipogénesis/fisiología , Adolescente , Adulto , Técnicas de Cultivo de Célula , Proliferación Celular , Células Cultivadas , Condrogénesis/fisiología , Humanos , Osteogénesis/fisiología , Ingeniería de Tejidos , Adulto Joven

RESUMEN

INTRODUCTION: Leptin, a 16 kDa anti-obesity hormone, exhibits various physiological properties. Interestingly, skin wound healing was proven to delay in leptin-deficient ob/ob mice. However, little is known on the mechanisms of this phenomenon. In this study, we attempted to elucidate a role of leptin in wound healing of skin. METHODS: Immunohistochemical analysis was performed to confirm the expression of the leptin receptor (Ob-R) in human and mouse skin. Leptin was topically administered to chemical wounds created in mouse back skin along with sustained-release absorbable hydrogel. The process of wound repair was histologically observed and the area of ulceration was measured over time. The effect of leptin on the proliferation, differentiation and migration of human epidermal keratinocytes was investigated. RESULTS: Ob-R was expressed in epidermal cells of human and mouse skin. Topical administration of leptin significantly promoted wound healing. Histological analysis showed more blood vessels in the dermal connective tissues in the leptin-treated group. The proliferation, differentiation/function and migration of human epidermal keratinocytes were enhanced by exogenous leptin. CONCLUSION: Topically administered leptin was proven to promote wound healing in the skin by accelerating proliferation, differentiation/function and migration of epidermal keratinocytes and enhancing angiogenesis around the wounded area. These results strongly suggest that topical administration of leptin may be useful as a treatment to promote wound healing in the skin.

Asunto(s)

Inductores de la Angiogénesis/administración & dosificación , Leptina/administración & dosificación , Neovascularización Fisiológica/efectos de los fármacos , Piel/lesiones , Cicatrización de Heridas/efectos de los fármacos , Administración Tópica , Inductores de la Angiogénesis/farmacología , Animales , Diferenciación Celular/efectos de los fármacos , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Modelos Animales de Enfermedad , Humanos , Queratinocitos/efectos de los fármacos , Leptina/farmacología , Ratones , Receptores de Leptina/metabolismo , Piel/metabolismo

RESUMEN

Melatonin regulates a variety of biological processes, which are the control of circadian rhythms, regulation of seasonal reproductive function and body temperature, free radical scavenging and so on. Our previous studies have shown that various cells exist in human and mouse tooth germs that express the melatonin 1a receptor (Mel1aR). However, little is known about the effects of melatonin on tooth development and growth. The present study was performed to examine the possibility that melatonin might exert its influence on tooth development. DP-805 cells, a human dental papilla cell line, were shown to express Mel1aR. Expression levels of mRNA for Mel1aR in DP-805 cells increased until 3 days after reaching confluence and decreased thereafter. Real-time reverse transcription-polymerase chain reaction showed that melatonin increased the expression of mRNAs for osteopontin (OPN), osteocalcin (OCN), bone sialoprotein (BSP), dentin matrix protein-1 (DMP-1) and dentin sialophosphoprotin (DSPP). Melatonin also enhanced the mineralized matrix formation in DP-805 cell cultures in a dose-dependent manner. These results strongly suggest that melatonin may play a physiological role in tooth development/growth by regulating the cellular function of odontogenic cells in tooth germs.

Asunto(s)

Papila Dental/efectos de los fármacos , Melatonina/farmacología , Animales , Diferenciación Celular/efectos de los fármacos , Línea Celular , Niño , Papila Dental/citología , Papila Dental/metabolismo , Proteínas de la Matriz Extracelular/genética , Proteínas de la Matriz Extracelular/metabolismo , Femenino , Humanos , Sialoproteína de Unión a Integrina/genética , Sialoproteína de Unión a Integrina/metabolismo , Masculino , Mandíbula/metabolismo , Mandíbula/patología , Ratones , Osteocalcina/genética , Osteocalcina/metabolismo , Osteopontina/genética , Osteopontina/metabolismo , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Ratas , Ratas Endogámicas F344 , Receptores de Melatonina/genética , Receptores de Melatonina/metabolismo , Sialoglicoproteínas/genética , Sialoglicoproteínas/metabolismo , Germen Dentario/metabolismo , Germen Dentario/patología

RESUMEN

INTRODUCTION: Leptin, a 16 kDa circulating anti-obesity hormone, exhibits many physiological properties. Recently, leptin was isolated from saliva; however, its function in the oral cavity is still unclear. In this study, we investigated the physiological role of leptin in the oral cavity by focusing on its effect on wound healing in the oral mucosa. METHODS: Immunohistochemical analysis was used to examine the expression of the leptin receptor (Ob-R) in human/rabbit oral mucosa. To investigate the effect of leptin on wound healing in the oral mucosa, chemical wounds were created in rabbit oral mucosa, and leptin was topically administered to the wound. The process of wound repair was histologically observed and quantitatively analyzed by measuring the area of ulceration and the duration required for complete healing. The effect of leptin on the proliferation, differentiation and migration of human oral mucosal epithelial cells (RT7 cells) was investigated using crystal violet staining, reverse transcription polymerase chain reaction (RT-PCR) and a wound healing assay, respectively. RESULTS: Ob-R was expressed in spinous/granular cells in the epithelial tissue and vascular endothelial cells in the subepithelial connective tissue of the oral mucosa. Topical administration of leptin significantly promoted wound healing and shortened the duration required for complete healing. Histological analysis of gingival tissue beneath the ulceration showed a denser distribution of blood vessels in the leptin-treated group. Although the proliferation and differentiation of RT7 cells were not affected by leptin, the migration of these cells was accelerated in the presence of leptin. CONCLUSION: Topically administered leptin was shown to promote wound healing in the oral mucosa by accelerating epithelial cell migration and enhancing angiogenesis around the wounded area. These results strongly suggest that topical administration of leptin may be useful as a treatment to promote wound healing in the oral mucosa.

Asunto(s)

Células Epiteliales/fisiología , Leptina/uso terapéutico , Mucosa Bucal/fisiología , Cicatrización de Heridas/efectos de los fármacos , Cicatrización de Heridas/fisiología , Administración Tópica , Adulto , Animales , Línea Celular , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Endoteliales/fisiología , Factor de Crecimiento Epidérmico/biosíntesis , Células Epiteliales/efectos de los fármacos , Factor 7 de Crecimiento de Fibroblastos/biosíntesis , Humanos , Masculino , Conejos , Receptores de Leptina/biosíntesis

RESUMEN

OBJECTIVE: Nerve growth factor (NGF) triggers long-term neuronal excitability. We examined its effect on murine bone marrow stromal cells (BMSC)-derived neurons. METHODS: With an optimal differentiation protocol, BMSCs were differentiated into neurons in culture. To confirm the probability of differentiation of BMSC into neuron, the expression of neuronal marker protein, neurofilament, was examined by immunocytochemistry. To examine the electrophysiological properties of BMSC-derived neurons, the field potentials were recorded either from nontreated (control) BMSC-derived neurons or from BMSC-derived neurons after the treatment with NGF by using extracellular recording techniques. RESULTS: Most BMSC-derived neurons showed spontaneous discharges whose amplitudes were up to 2 mV. When NGF at a concentration of 100 ng/ml was applied to BMSC-derived neurons, the amplitudes of discrete field potentials were gradually enlarged within 1 min after NGF application and peaked 3 min later (20-fold the size of control). However, the enlargement of the amplitudes of field potentials almost disappeared 5 min after NGF application. CONCLUSION: This finding indicates that neuronal cells derived from murine BMSCs generate discrete field potential activities spontaneously and that NGF has the effect of enlarging transient, but not sustained, electrical activity of BMSC-derived neurons.

Asunto(s)

Potenciales de Acción/fisiología , Células de la Médula Ósea/fisiología , Factor de Crecimiento Nervioso/fisiología , Neuronas/fisiología , Células del Estroma/fisiología , Potenciales de Acción/efectos de los fármacos , Animales , Células de la Médula Ósea/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/fisiología , Células Cultivadas , Masculino , Ratones , Ratones Endogámicos C57BL , Factor de Crecimiento Nervioso/farmacología , Proteínas de Neurofilamentos/metabolismo , Neuronas/metabolismo , Células del Estroma/efectos de los fármacos

RESUMEN

Melatonin, discovered in 1958, is secreted by the pineal gland primarily during the night. Its secretion is controlled by the light/dark cycle of the environment. Melatonin is also produced in and secreted by various extrapineal organs, tissues and cells and its synthesizing enzyme arylalkylamine N-acetyltransferase (AANAT) is expressed in various extrapineal organs, tissues and cells. Recently, it was reported that melatonin is present in saliva, but it is not certain where melatonin was synthesized and whether it was secreted into saliva and what function it may have in saliva. The present study was performed to investigate where melatonin was synthesized and whether it was secreted by salivary glands into saliva. We performed immunohistochemical analysis of the expression of AANAT in rat parotid, submandibular and sublingual glands and the expression of both AANAT and hydroxyindole-O-methyltransferase (HIOMT) in human submandibular glands. We evaluated the expression of AANAT and HIOMT mRNA in rat submandibular glands by quantitative reverse transcription-polymerase chain reaction. As a result, we observed expression of AANAT in epithelial cells of striated ducts in rat salivary glands and expression of AANAT, HIOMT and melatonin in epithelial cells of striated ducts in human submandibular glands. In addition, we also confirmed the expression of the most potent melatonin receptor, melatonin 1a receptor, in rat buccal mucosa. Our findings suggest that melatonin might be produced and secreted by salivary glands directly into saliva and that it might play some physiological role in the oral cavity.

Asunto(s)

Acetilserotonina O-Metiltransferasa/metabolismo , N-Acetiltransferasa de Arilalquilamina/metabolismo , Melatonina/biosíntesis , Glándulas Salivales/enzimología , Acetilserotonina O-Metiltransferasa/análisis , Acetilserotonina O-Metiltransferasa/genética , Animales , N-Acetiltransferasa de Arilalquilamina/análisis , N-Acetiltransferasa de Arilalquilamina/genética , Humanos , Inmunohistoquímica , Masculino , Mucosa Bucal/citología , ARN Mensajero/análisis , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-Dawley , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Glándulas Salivales/citología

RESUMEN

Leptin, a 16 kDa non-glycolated polypeptide of 146 amino acids produced by the ob gene, has a variety of physiological roles not only in lipid metabolism, hematopoiesis, thermogenesis and ovarian function, but also in angiogenesis. This study focuses to investigate the possibility that leptin, as an angiogenic factor, may regulate the angiogenesis during tooth development. We firstly studied the expression of leptin and vascular endothelial growth factor (VEGF) during tooth development immunohistochemically. This investigation revealed that leptin is expressed in ameloblasts, odontoblasts, dental papilla cells and stratum intermedium cells. This expression pattern was similar to that of VEGF, one of the most potent angiogenic factors. Interestingly, more leptin-positive cells were observed in the upper third portion of dental papilla, which is closest to odontoblastic layer, compared to middle and lower thirds. Moreover, in the dental papilla, more CD31 and/or CD34-positive vascular endothelial cells were observed in the vicinity of ameloblasts and odontoblasts expressing leptin and VEGF. These findings strongly suggest that ameloblasts, odontoblasts and dental papilla cells induce the angiogenesis in tooth germs by secretion of leptin as well as VEGF.

Asunto(s)

Leptina/metabolismo , Neovascularización Fisiológica , Germen Dentario/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Animales , Humanos , Inmunohistoquímica , Leptina/análisis , Ratas , Ratas Endogámicas F344 , Germen Dentario/química , Germen Dentario/crecimiento & desarrollo , Factor A de Crecimiento Endotelial Vascular/análisis

RESUMEN

INTRODUCTION: Despite the clinical adoption of distraction osteogenesis (DO), studies examining the bone healing process at the distraction gap in osteoporotic bone are limited. We examined the effect of osteoporosis in the ovariectomized rat on DO. MATERIAL AND METHODS: Mid-diaphyseal osteotomies were performed on the femurs of ovariectomized (OVX) rats. External distractors were placed on these rats and also on sham-ovariectomized rats. After a 7-day latency period, distraction was carried out at a rate of 0.5mm/day for 10 days. The bone volume (BV) of the distraction gap was measured by Micro-focused X-ray computed tomography (micro-CT) at 0, 2, and 4 weeks after completion of the distraction, and the distraction gap was examined histologically. RESULTS: The BV of the distraction gap in the OVX group was significantly lower than that in the sham group at 2 and 4 weeks after completion of distraction (p<0.01). On histological examination, the distraction gap in the OVX group was filled with scattered smaller bone trabeculae than those seen in the sham group at 4 weeks after completion of distraction. Osteoclast numbers at the distraction gap in the OVX group were significantly increased when compared to the sham group (p<0.01). CONCLUSION: Bone turnover with osteoclast predominance in ovariectomized rats is likely to be the cause of a reduction in new bone formation at the distraction gap.

Asunto(s)

Fémur/cirugía , Osteogénesis por Distracción/métodos , Osteoporosis/fisiopatología , Fosfatasa Ácida/análisis , Animales , Biomarcadores/análisis , Peso Corporal , Densidad Ósea/fisiología , Médula Ósea/patología , Médula Ósea/fisiopatología , Matriz Ósea/patología , Matriz Ósea/fisiopatología , Cartílago/patología , Cartílago/fisiopatología , Tejido Conectivo/patología , Tejido Conectivo/fisiopatología , Diáfisis/patología , Diáfisis/fisiopatología , Diáfisis/cirugía , Modelos Animales de Enfermedad , Fijadores Externos , Femenino , Fémur/patología , Fémur/fisiopatología , Isoenzimas/análisis , Osteoclastos/patología , Osteogénesis/fisiología , Osteogénesis por Distracción/instrumentación , Osteoporosis/patología , Ovariectomía , Ratas , Ratas Wistar , Fosfatasa Ácida Tartratorresistente , Factores de Tiempo , Cicatrización de Heridas/fisiología , Microtomografía por Rayos X

RESUMEN

Melatonin influences the release of growth hormone and cortisol in humans, and it was recently reported that it promoted bone formation. On the other hand, fibroblast growth factor-2 (FGF-2) was reported to facilitate the proliferation of osteoblasts. In the present study, we examined the effect of recombinant human FGF-2 and melatonin on the promotion of osteogenesis around titanium implants. Twenty-four 10-week-old female rats of the Wistar strain received titanium implants in both tibiae. In the experimental groups, 100 mg/kg body weight of melatonin was administered by intraperitoneal injection for 4 weeks after implantation and 10 microg of FGF-2 was locally injected around the implant sites 5 days after implantation. The control groups were administered saline only. In the control group, few newly formed bone could be seen around the implants. It was observed to be in direct contact with the implant surface, but otherwise unmineralized connective tissue was occasionally interposed. In the experimental group, newly formed bone was observed around the titanium implant. In addition, in contrast to the control group, abundant bone trabeculae were seen in the medullary canal region. Bone trabeculae were directly connected to existing cortical bone. These results strongly suggested that melatonin and FGF-2 have the potential to promote osseointegration.

Asunto(s)

Desarrollo Óseo/efectos de los fármacos , Factor 2 de Crecimiento de Fibroblastos/farmacología , Melatonina/farmacología , Prótesis e Implantes , Animales , Femenino , Factor 2 de Crecimiento de Fibroblastos/administración & dosificación , Humanos , Inyecciones Intraperitoneales , Melatonina/administración & dosificación , Ratas , Ratas Wistar , Proteínas Recombinantes/farmacología

RESUMEN

Recently, it has become important to develop effective material to be used as scaffolds for bone tissue engineering. Therefore, we fabricated new three-dimensional (3D) scaffolds consisting of biodegradable poly(D,L-lactide-co-glycolic acid)(PLGA)(75/25) with anti-washout type AC (aw-AC) particles. The aim of this study was to evaluate this new scaffold concerning its basic properties and biocompatibility. The obtained scaffolds were observed with scanning electron microscopy (SEM), and measured for porosity, shrinkage and biaxial compressive strengths. It was shown that PLGA with aw-AC composite scaffolds (aw-AC/PL) showed a greater strength and stability than PLGA scaffolds (PL). Also, the mass reduction of aw-AC/PL during incubation decreased compared to that of PL. The number of MC3T3-E1 cell in PL and aw-AC/PL was counted at 5 h, 1 week, and 2 weeks after cell seeding. As a result, aw-AC/PL exhibited a superior performance in terms of attachment and proliferation compared to PL. Histologically, aw-AC/PL showed an excellent response toward soft tissues. Therefore, it was shown that aw-AC/PL was more biocompatible than PL. In conclusion, it was strongly suggested that aw-AC/PL was more useful for cell transplantation than PL in bone tissue engineering.

Asunto(s)

Sustitutos de Huesos/síntesis química , Ácido Láctico/química , Ácido Poliglicólico/química , Ingeniería de Tejidos/métodos , Andamios del Tejido , Animales , Regeneración Ósea , Sustitutos de Huesos/química , Sustitutos de Huesos/farmacología , Adhesión Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Resinas Compuestas/química , Fuerza Compresiva , Humanos , Ácido Láctico/farmacología , Masculino , Ensayo de Materiales , Tamaño de la Partícula , Ácido Poliglicólico/farmacología , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Polvos , Ratas , Ratas Wistar , Estrés Mecánico , Andamios del Tejido/química

RESUMEN

We present here the clinical, morphological and immunohistochemical features of a pigmented squamous cell carcinoma (SCC) in the oral mucosa of the hard palate of a 76-year-old Japanese man. He underwent a partial resection of the maxilla subsequent to radiotherapy. The tumor was typical, moderately well-differentiated SCC but had many melanocytes (melanocytosis) within it. Immunohistochemical analysis for stem cell factor (SCF) and endothelin-1, both of which are known to stimulate proliferation and differentiation of melanocytes, revealed prominent expression of both factors in the neoplastic squamous cells of the pigmented SCC, while the non-pigmented oral SCC showed little sign of either factor. These findings strongly suggest that SCF and endothelin-1 secreted by neoplasmic squamous cells are involved in the emergence of a rare variant of oral SCC.

Asunto(s)

Carcinoma de Células Escamosas/química , Endotelina-1/análisis , Neoplasias Palatinas/química , Factor de Células Madre/análisis , Anciano , Carcinoma de Células Escamosas/complicaciones , Carcinoma de Células Escamosas/patología , Humanos , Masculino , Melanocitos/patología , Melanosis/complicaciones , Neoplasias Palatinas/patología

RESUMEN

Tissue response to apatite cement (AC) containing atelocollagen (AC (ate)) was evaluated using conventional AC (c-AC) as a control material. At one week, the only difference between AC (ate) and c-AC was found in the soft tissue response. With c-AC, a moderate inflammatory response was exhibited: small particles of c-AC were scattered in the cutaneous tissue and many foreign body giant cells were aggregated around the scattered c-AC, whereas AC (ate) showed only a slight inflammatory response with few foreign body giant cells. In terms of bone tissue response, difference between AC (ate) and c-AC was observed at four weeks. New bone formation was observed along the cement at the edge of the pre-existing cortical bone in both c-AC and AC (ate). However, in the case of AC (ate), more abundant and thicker new bone was formed along the cement in the bone marrow when compared with c-AC.

Asunto(s)

Cementos para Huesos/farmacología , Regeneración Ósea/efectos de los fármacos , Colágeno/farmacología , Hidroxiapatitas/farmacología , Animales , Cementos para Huesos/toxicidad , Huesos/efectos de los fármacos , Bovinos , Colágeno/toxicidad , Reacción a Cuerpo Extraño/etiología , Hidroxiapatitas/toxicidad , Masculino , Ratas , Ratas Wistar , Tejido Subcutáneo/efectos de los fármacos , Difracción de Rayos X