Nanog, Stat-3, and Sox-5 involvement in human fetal temporomandibular joint late development.

Background and aim: The temporomandibular joint (TMJ) is a synovial joint that allows the complex movements essential for life. It connects the jawbone to the skull, working as a sliding hinge. Moreover, pluripotent stem cells are a source of precursors and tissue-specific cells in developing organisms, however, their biodistribution in developing fetal tissues is weakly studied. The aim of our study was analyse immunohistochemical expression of Nanog, Oct-4, Sox-2 and Stat-3 and Sox-5, in TMJ tissue samples from human fetuses aged between the 12th and 20th weeks of intrauterine life. Materials and methods: We fixed and processed TMJ tissue samples from human fetuses, histological sections and immunohistochemical procedures were carried out. Results: TMJ histological studies examination did not reveal any difference in the tissue organization between the samples in the studied periods. Immunohistochemical analysis demonstrated that Oct-4 and Sox-2 lack their expression in TMJ. In contrast, Nanog was expressed in nucleous of proliferative layer of mandibular condyle, Stat-3 was expressed in nuclear cells of articular disc, Stat-3 and Sox-5 showed positive nuclear and cytoplasmic immunostaining in codrocyte layers and in ossification areas. Conclusions: Nanog acts in maintanence of pluripotency, Stat-3 in articular disc acts as a transcriptional factor. Stat-3 and Sox-2 act in chondrocyte and osteoblast diferentiation. Distribution of the cells, which express Nanog, Stat-3, and Sox-5 in TMJ tissue during fetal development, can help further understand its physiology, pathology, and repairing capacities.

Evaluation of the comparative effects of infrared and red laser photobiomodulation therapy on skeletal muscle atrophy in an immobilization model in rats / Avaliação comparativa dos efeitos da terapia de fotobiomodulação com laser infravermelho e vermelho na atrofia muscular esquelética em modelo de imobilização em ratos

INTRODUCTION: Skeletal muscle atrophy leads to a reduction in muscle strength, functionality, and the quality of life of individuals. OBJECTIVE: To explore the effects of two different wavelengths (red and infrared) of laser PBMT on muscle atrophy and its active ingredients on skeletal muscle atrophy using an in vivo model of muscle atrophy. METHODS: Thirty-two Wistar rats were randomly divided into four experimental groups: control (CG) animals were not immobilized and did not receive any type of treatment; immobilized animals with no treatment (ImC); immobilized animals submitted to red laser with wavelength of 660 nm (ImR) and near-infrared laser with wavelength of 808 nm (ImIR) treatments. The treatments were applied daily, at 2 points in the right gastrocnemius muscle (cranial and caudal), through the punctual contact technique, for 9 sessions, with the first application immediately after removing the cast. RESULTS: The histological results demonstrated that in both treated groups (red and infrared wavelengths) a reduction of the inflammatory infiltrate and less connective tissue thickening when compared to the ImC. However, only infrared light was observed regenerating muscle fibers and an increase in the number of oxidative fibers (type I). CONCLUSION: These results suggest that red and infrared wavelength laser PBMT were able to promote changes in the morphology of the gastrocnemius muscle submitted to atrophy in an experimental immobilization model, reducing the inflammatory infiltrate and the formation of intramuscular connective tissue. However, infrared laser PBMT promoted more evident positive effects by increasing regenerating muscle fibers and the number of oxidative fibers.

Nanog, Stat-3, and Sox-5 involvement in human fetal temporomandibular joint late development

The temporomandibular joint (TMJ) is a synovial joint that allows the complex movements essential for life. It connects the jawbone to the skull, working as a sliding hinge. Moreover, pluripotent stem cells are a source of precursors and tissue-specific cells in developing organisms, however, their biodistribution in developing fetal tissues is weakly studied. The aim of our study was analyse immunohistochemical expression of Nanog, Oct-4, Sox-2 and Stat-3 and Sox-5, in TMJ tissue samples from human fetuses aged between the 12th and 20th weeks of intrauterine life.

Association of Transcranial Direct Current Stimulation and Neurofeedback With Declarative Memory and Cerebral Arterial Flow in University Students: Protocol for a Double-blind Randomized Controlled Study.

BACKGROUND: The performance of a task depends on ongoing brain activity, which can be influenced by attention, excitement, or motivation. Scientific studies have confirmed that mindfulness leads to better performance, health, and well-being. However, these cognitive efficiency modulating factors are nonspecific, can be difficult to control, and are not suitable to specifically facilitate neural processing. OBJECTIVE: The aim of this study is to evaluate the effects of transcranial direct current stimulation associated with neurofeedback on declarative memory and cerebral blood flow in university students. METHODS: In this study, we will use transcranial direct current stimulation, a low-cost physical resource that is easy to apply, has few adverse effects, and is associated with a neurofeedback resource. This, in turn, has been shown to be a training program capable of improving working memory function. RESULTS: Participants will be recruited between July 2022 and December 2022. This study is expected to conclude in July 2023. CONCLUSIONS: This study will provide preliminary results on the benefits of using the direct current neurostimulation and neurofeedback tools on the participants being analyzed. TRIAL REGISTRATION: Brazilian Clinical Trials Registry RBR-7zs8b5; https://ensaiosclinicos.gov.br/rg/RBR-7zs8b5. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/36294.

The immunomodulatory potential role of mesenchymal stem cells in diseases of the central nervous system

Several studies indicate the role of mesenchymal stem cells (MSCs) as an important tool in regenerative medicine associated with injuries that affect the central nervous system (CNS). The MSCs have the capacity to differentiate into cells of the embryonal tissue, such as the mesoderm. So, these cells can be found in a variety of tissues. Also, the MSCs can release immunomodulatory and neurotrophic factors performance as inflammation mediators operating in injured tissue the regeneration. Furthermore, they can differentiate into neural, like cells in vitro. Thereby, because of the high immunomodulatory role of MSCs, this review sought to describe the main immunomodulatory mechanisms performed by MSCs in CNS recovery after tissue injury or neurodegenerative diseases. Methods: PubMed and ScienceDirect were searched between January 2011 to March 2021 and 43 articles met the criteria of the review. Results: This systematic review indicate that MSCs were used in vivo experimental Multiple Sclerosis (MS), Parkinson's disease (PA), Alzheimer's disease (AD), Amyotrophic Lateral Sclerosis (ALS), Ischemic Stroke (IS) and Traumatic Brain Injury (TBI). The treatment MSCs were usually from human origin, derived from bone marrow and administered intravenously. Discussion/Conclusion: It was shown that MSCs, independent from origin or administration pathway, can reduce inflammation and help in the recovery and preservation of injured neural tissue. Thus, the use of MSCs represents a potential therapeutic option in the treatment of neurological disorders mediated by inflammatory processes.

Evaluation of the articular cartilage in the knees of rats with induced arthritis treated with curcumin.

This study was designed to evaluate the anti-inflammatory effects of a curcumin treatment on the knee of rats with induced osteoarthritis. Fifteen adult rats were used and divided in three groups: the osteoarthritis group (OAG), control group (CG-without induction of osteoarthritis), and curcumin-treated osteoarthritis group (COAG). Osteoarthritis was induced in the right knee of rats in the OAG and COAG by administering an intra-articular injection of 1 mg of zymosan. Fourteen days after induction, 50 mg/kg curcumin was administered by gavage daily for 60 days to the COAG. After the treatment period, rats from all groups were euthanized. Medial femoral condyles were collected for light microscopy and immunohistochemical staining. The expression of SOX-5, IHH, MMP-8, MMP-13, and collagen 2 (Col2) was analyzed. The COAG exhibited an increase in the number of chondrocytes in the surface and middle layers compared with that of the OAG and CG, respectively. The COAG also showed a decrease in the thicknesses of the middle and deep layers compared with those of the OAG, and an increase in Col2 expression was observed in all articular layers (surface, middle, and deep) in the COAG compared with that in the OAG. SOX-5 expression was increased in the surface and deep layers of the COAG compared with those in the OAG and CG. Based on the results of this study, the curcumin treatment appeared to exert a protective effect on cartilage, as it did not result in an increase in cartilage thickness or in MMP-8 and MMP-13 expression but led to increased IHH, Col2, and SOX-5 expression and the number of chondrocytes.

Rat facial nerve regeneration with human immature dental pulp stem cells

Facial paralysis can result in severe implications for the patients. However, stem cell biology has become an important field in regenerative medicine since the discovery and characterization of mesenchymal stem cells. Our aim was to evaluate the regeneration after facial nerve crush injury and application of human immature dental pulp stem cells (iDPSC). For this study 70 Wistar rats underwent a unilateral facial nerve crush injury and were divided into two groups: Group I (GI): Crushed; Group II (GII): Crushed and iDPSC, and distributed into study periods of 3, 7, 14, 21, and 42 postoperative days. Facial nerve regeneration was analyzed via functional recovery of whisker movement, histomorphometric analysis, and immunoblotting assay. The results show that GII had complete functional recovery at 14 days, while GI recovered after 42 days. Also, regarding the facial nerve trunk, GII presented histological improvement, evidencing better axonal and structural organization of the myelin sheath, and exhibited statistically higher values for the outer and inner perimeters and g-ratio. Nevertheless, GI exhibited statistically higher values for the thickness of myelin sheath. In the buccal branch, no differences were observed for all parameters between groups. At 42 days, both groups GI and GII were close to the levels observed for the control group. Concerning nerve growth factor expression, GII exhibited statistically greater values (p < 0.05) compared with the control group at 7 days. In summary, a single injection of human iDPSC promoted a positive effect on regeneration of the facial nerve trunk after 14 days and provided an alternative to support regeneration following peripheral nerve injury.

Rat facial nerve regeneration with human immature dental pulp stem cells

Facial paralysis can result in severe implications for the patients. However, stem cell biology has become an important field in regenerative medicine since the discovery and characterization of mesenchymal stem cells. Our aim was to evaluate the regeneration after facial nerve crush injury and application of human immature dental pulp stem cells (iDPSC). For this study 70 Wistar rats underwent a unilateral facial nerve crush injury and were divided into two groups: Group I (GI): Crushed; Group II (GII): Crushed and iDPSC, and distributed into study periods of 3, 7, 14, 21, and 42 postoperative days. Facial nerve regeneration was analyzed via functional recovery of whisker movement, histomorphometric analysis, and immunoblotting assay. The results show that GII had complete functional recovery at 14 days, while GI recovered after 42 days. Also, regarding the facial nerve trunk, GII presented histological improvement, evidencing better axonal and structural organization of the myelin sheath, and exhibited statistically higher values for the outer and inner perimeters and g-ratio. Nevertheless, GI exhibited statistically higher values for the thickness of myelin sheath. In the buccal branch, no differences were observed for all parameters between groups. At 42 days, both groups GI and GII were close to the levels observed for the control group. Concerning nerve growth factor expression, GII exhibited statistically greater values (p < 0.05) compared with the control group at 7 days. In summary, a single injection of human iDPSC promoted a positive effect on regeneration of the facial nerve trunk after 14 days and provided an alternative to support regeneration following peripheral nerve injury.

The effects of joint immobilization on articular cartilage of the knee in previously exercised rats.

Studies have determined the effects of joint immobilization on the articular cartilage of sedentary animals, but we are not aware of any studies reporting the effects of joint immobilization in previously trained animals. The objective of the present study was to determine whether exercise could prevent degeneration of the articular cartilage that accompanies joint immobilization. We used light microscopy to study the thickness, cell density, nuclear size, and collagen density of articular cartilage of the femoral condyle of Wistar rats subjected to aerobic physical activity on an adapted treadmill five times per week. Four groups of Wistar rats were used: a control group (C), an immobilized group (I), an exercised group (E), and an exercised and then immobilized group (EI). The right knee joints from rats in groups I and EI were immobilized at 90 °C of flexion using a plastic cast for 8 weeks. Cartilage thickness decreased significantly in group I (mean, 120.14 ± 15.6 µm, P < 0.05), but not in group EI (mean, 174 ± 2.25), and increased significantly in group E (mean, 289.49 ± 9.15) compared with group C (mean, 239.20 ± 6.25). The same results were obtained for cell density, nuclear size, and collagen density (in all cases, P < 0.05). We concluded that exercise can prevent degenerative changes in femoral articular cartilage caused by immobilization of the knee joint.

Análise da força de tração necessária para a remoção de cimento resinoso fixado em raízes preparadas com diferentes substâncias químicas / Analysis of the force required to remove resin cement from roots prepared with different chemicals

OBJETIVO: Avaliar in vitro, a influência das substâncias químicas utilizadas durante o preparo endodôntico na força de tração do cimento resinoso Rely-X (3M, Sumaré, Brasil) na dentina radicular bovina. MÉTODOS: Utilizou-se 72 dentes bovinos que tiveram suas coroas seccionadas e raízes padronizadas. A seguir, os espécimes foram incluídos em blocos de resina e receberam tratamento químico por 10 minutos com hipoclorito de sódio nas concentrações de 0,5 por cento, 1 por cento, 2,5 por cento, 5,25 por cento ou gel de clorexidina a 2 por cento, além do grupo-controle que recebeu água destilada. Em seguida os espécimes foram imersos em solução de EDTA a 17 por cento por 3 minutos. Dois espécimes de cada grupo foram submetidos à microscopia eletrônica de varredura para avaliação da superfície. Os espécimes para o ensaio de teste de tração receberam condicionamento com ácido fosfórico a 37 por cento por 15 segundos, sistema adesivo Single-Bond (3M, Sumaré, Brasil) e sobre este aplicado o cimento resinoso Rely-X (3M, Sumaré, Brasil). RESULTADOS: Os resultados em Kgf foram: GClorex (2,26); GNaOCl-0,5 por cento (7,92); GNaOCl-1 por cento (9,70); GNaOCl-2,5 por cento (9,05); GNaOCl-5,25 por cento (8,91); GA (0,61). CONCLUSÃO: O hipoclorito de sódio nas concentrações testadas aumentou a força de adesão do cimento resinoso na dentina de forma significativa frente água destilada e gel de clorexidina a 2 por cento. A observação na microscopia eletrônica de varredura mostrou que a estrutura de dentina radicular que fora tratada com hipoclorito de sódio apresentava túbulos dentinários com diâmetros aumentados, menor quantidade de dentina intertubular, além de áreas de depressões, diferentemente dos grupos-controle e gel de clorexidina a 2 por cento.

OBJECTIVE: This study assessed in vitro how the chemicals used in the preparation of root canals affected the force required to remove the resin cement Rely-X (3M, Sumaré, Brazil) from bovine root dentin. METHODS: The crowns of 72 bovine teeth were sectioned and the roots were standardized. The specimens were then placed in resin blocks and treated for 10 minutes with sodium hypochlorite at 0.5 percent, 1 percent, 2.5 percent or 5.25 percent or chlorhexidine gel at 2 percent. The control group was treated with distilled water. Next, the specimens were soaked in 17 percent EDTA for 3 minutes. The surfaces of two specimens from each group were assessed by electron scanning microscopy. The tested specimens were then treated with 37 percent phosphoric acid for 15 minutes, adhesive system Single-Bond (3M, Sumaré, Brazil) and the resin cement Rely-X (3M, Sumaré, Brazil) was applied over it. RESULTS: The results in Kgf were: GChlorhex (2.26); GNaOCl-0.5 percent (7.92); GNaOCl-1 percent (9.70); GNaOCl-2.5 percent (9.05); GNaOCl-5.25 percent (8.91); GA (0.61). CONCLUSION: Sodium hypochlorite in the tested concentrations increased the adhesion of the resin cement to the dentin significantly when compared with water and 2 percent chlorhexidine. Electron scanning microscopy showed that the structure of the root dentin treated with sodium hypochlorite presented widened dentinal tubules, less intertubular dentin and depression areas, all of which were not observed in the roots treated with water and 2 percent chlorhexidine gel.

Estimativa da variação topográfica na determinação do ponto pório / Estimate of the topographical variation in the determination of the porion point

A localização correta do ponto pório é de grande importância nas avaliações ortodônticas. Objetivo: esta-belecer indicadores para a correta localização do pório anatômico diante do pório cefalométrico. Métodos: Foram avaliadas quarenta radiografias cefalométricas laterais de pacientes leucodermas de ambos os gêneros, com idade média de 8,9 anos, obtidas num banco de dados. Os indicadores escolhidos foram o meato acústico externo, a imagem radiográfica fornecida por uma oliva padronizada do aparelho de raios x Rotogra-ph Plus®, o plano de Frankfurt e o plano pterigoideo vertical (PTV). Resultados: o ponto pório cefalométrico localizou-se, em média, a 6,41 mm da linha PTV e a 6,49 mm do plano horizontal de Frankfurt e correlação positiva entre pório anatômico e cefalométrico (r = 0,9852) e correlação positiva entre pório anatômico e cefalométrico (r = 0,9852). Conclusão: a oliva patenteada sinaliza corretamente a localização do ponto pório, minimizando as distorções do exame radiográfico e facilitando a utilização cefalométrica deste ponto pouco visível cefalometricamente.

Corneal Reconstruction with Tissue-Engineered Cell Sheets Composed of Human Immature Dental Pulp Stem Cells

To determine the outcome of the use of a tissue-engineered cell sheet composed of human undifferentiated immature dental pulp stem cells (hIDPSC) for ocular surface reconstruction in an animal model of total limbal stem cell deficiency (LSCD). LSCD was induced by the application of 0.5 M NaOH to the right eye of rabbits for 25 seconds (mild chemical burn [MCB]) and for 45 seconds (severe chemical burn [SCB]). After 1 month, a superficial keratectomy was performed to remove the fibrovascular pannus that covered the animals' burned corneas. A tissue-engineered hIDPSC sheet was transplanted onto the corneal bed and then covered with deepithelialized human amniotic membrane (AM). In the respective control groups, the denuded cornea was covered with AM only. After 3 months, a detailed analysis of the rabbit eyes was performed with regard to clinical aspect, histology, electron microscopy, and immunohistochemistry. Corneal transparency of the rabbit eyes that underwent hIDPSC transplantation was improved throughout the follow-up, while the control corneas developed total conjunctivalization and opacification. Rabbits from the MCB group showed clearer corneas with less neovascularization. The clinical data were confirmed by histologic analysis that showed healthy uniform corneal epithelium, especially in the MCB group. The presence of hIDPSC was detected using an anti-hIDPSC antibody. The corneal tissue also showed positive immunostaining with anti-human antibodies. In the control corneas, none of these antigens were detected. Overall, these data showed that transplantation of a tissue-engineered hIDPSC sheet was successful for the reconstruction of corneal epithelium in an animal model of LSCD.

Three-dimensional characteristics of the interface epithelium-connective tissue surface of fingeres lamina propria of Cebus apella monkey: scanning electron microscopy study / Características tri-dimensionales superficiales de la lámina propia de los dedos de monos Cebus apella: interfase del tejido epitelial-conectivo del estudio con microscopía electrónica de barrido

In the present paper were analysed the three-dimensional characteristics of the interface epithelium-connective tissue surface of finger prints of Cebus apella monkey employing the scanning electron microscopic methods. The connective tissue core (CTC) and epithelial papillae were examined verifying the three-dimensional configuration of the tissue projections. The samples were fixed in Bouin solsution for histologic preparations and in modified Karnovsky for examine to observe in scanning electron microscopy. After treatment in the 10 percent NaOH solution during 3 to 5 day s, the surface of finger prints revealed a distribution of CTC of lamina propria in situ showing original three-dimensional SEM images. The linear and circular dispositions CTC, and the furrows were clearly identified. Each pointed papilla presented a large base and longitudinal disposition of thick collagen fiber bundles and in some areas with a complex reticular formations. The longitudinal furrows between the pointed papillae exhibited a dense layer of connective tissue and showed only low CTC or laminar in shape. The presence of numerous foramina of sweat gland were noted in three-dimensional SEM images.

Se analizaron tridimensionalmente las características de la interfase del tejido epitelio-conectivo en la superficie de huellas dactilares de mono Cebus apella, empleando el microscopio electrónico de barrido. El núcleo del tejido conectivo (NTC) y las papilas epiteliales se examinaron en las tres dimensiones. Las muestras fueron fijadas en solución histológica Bouin para los preparativos y en Karnovsky modificada para examinar y observar en el microscopio electrónico de barrido. Después del tratamiento en solución de NaOH al 10 por ciento, durante 3 a 5 días, la superficie de las huellas dactilares revelaron una distribución de NTC de lámina propia in situ mostrando imágenes en tres dimensiones originales con microscopio electrónico de barrido. Las disposiciones lineal y circular del NTC están claramente identificadas. Cada papila señalada presenta una gran base y la disposición longitudinal de gruesos haces de fibras de colágeno y, en algunas zonas con formaciones de un complejo reticular. Los surcos longitudinales entre las papilas señaladas mostraron una densa capa de tejido conectivo con NTC bajos o de forma laminar. La presencia de numerosos forámenes de las glándulas sudoríparas se observaron en tres dimensiones.

Ultrastructure of the adhesion of bacteria to the epithelial cell membrane of three-day postnatal rat tongue mucosa: a transmission and high-resolution scanning electron microscopic study

Togue mucosa surface of 3-day postnatal rats was examined under transmission electron microscopy (TEM) and high-resolution scanning electron microscopy (HRSEM). For HRSEM analysis, the specimens were fixed in the same solution for 24 h, postfixed in 2 percent osmiun tetroxide, critical-point dried and coated with platinum-palladium. For TEM analysis, the specimens were fixed using modified Karnovsky solution and embedded in Spurr resin. The results revealed the presence of numerous microplicae in the membrane surface of keratinized epithelial cells to which groups of bacteria were attached. These bacteria were staphylococcus and coccus organized either in rows or at random, which were visualized in three-dimensional HRSEM images. At high magnification, the TEM images revealed the adhesion of bacteria to the cell membrane through numerous filamentous structures comprising the glycocalyx. The fine fibrillar structures rising from each bacterium and from cell membrane were clearly seen. These characteristics on bacteria structure may be used for future control or prevention of bacterial diseases and for installation of the oral native flora.

A superfície lingual de ratos de três dias de idade foi examinada em microscópia eletrônica de transmissão (MET) e em microscópia eletrônica varredura de alta resolução (MEVAR). Para o método de MEVAR, os espécimes foram fixados na mesma solução por 24 h, pós fixados em solução de tetróxido de ósmio a 2 por cento, secos em ponto crítico e cobertos com platina- paládio. Para análise em MET, os espécimes foram fixados utilizando-se solução de Karnovsky modificada e emblocadas em resina Spurr. Os resultados mostraram a presença de numerosas micropregas na membrana superficial das células epiteliais queratinizadas, nas quais estavam aderidos grupos de bactérias. Estas bactérias eram estafilococos e cocos, organizados em fileiras ou a esmo, e puderam ser observadas em imagens tri-dimensionais em MEVAR. Em maiores aumentos, as imagens em MET revelaram a adesão de bactérias nas células por meio de numerosas estruturas filamentares compondo o glicocálice. As delicadas estruturas filamentares na periferia das bactérias e das células foram nitidamente identificadas. Estas características da estrutura bacteriana podem ser utilizadas, no futuro, para controle e prevenção de doenças bacteriana, bem como para a instalação da flora oral nativa.

Ultrastructure of bacteria adhesion in cell membrane of young mouse lingual mucosa

Lingual mucosa of young mouse was examined by transmission and high resolution scanning electron microscopic images (HRSEM). The specimens were fixed with modified Karnovsky solution and embedded in Spurr resin for transmission electron micrascopy. Thin sections of 80 nm were cut and examined in the Jeol 1010 transmission electron microscope. For HRSEM method, the specimens were fixed in the same solution, postfixed in osmiun tetroxide, critical point dried and coated with palladium. The samples were examined under Hitachi S-900, SEM microscope. The results revealed groups of bacteria attached to the surface of keratinized epithelial cells. These streptococcus and coccus attached on the cell membrane were noted in the three-dimensional SEM images- At high magnification, the transmission electron microscopic images demonstrated the adhesion of bacteria to the cell membrane through numerous fimbria comprising the glycocalyx. The fine fibrillar structure rising from bacteria were clearly seen.

A mucosa lingual de camundongos jovens foi examinada através de imagens de microscopia eletrônica de transmissão e de varredura de alta resolução. Os espécimes foram fixados em solução modificada de Karnovsky e emblocadas em resina Spurr para a microscopia eletrônica de transmissão. Cortes finos de 80 nm foram feitos e examinados em um microscópio eletrônico de transmissão Jeol 1010. Para a microscopia eletrônica de varredura de alta resolução os espécimes foram imersos na mesma solução, pós fixados em tetróxido de ósmio, secos e cobertos com paládio. As amostras foram examinadas em um microscópio eletrônico de varredura Hitachi S-900. Os resultados revelaram grupos de bactéria aderidos à superfície queratinizada das células epiteliais. Estes estreptococos e cocos aderidos à membrana celular foram notados em imagens tridimensionais. Em aumentos maiores, as imagens de microscopia eletrônica de transmissão demonstraram a adesão de bactéria à membrana celular através de numerosas fimbrias compondo o glicocalice. A estrutura fibrilar emergindo da bactéria foi claramente observada.

Ultrastructural aspects of the muscle of theanterior third of rabbit

The structural organization of the anterior third of adult rabbit tongue was studied using light microscopy andconventional and high resolution scanning electron microscopy. Histologically, the muscle layer of the tongue consistedof muscle fibers arranged vertically, transversally and longitudinally. These fibers were surrounded by connectivetissue containing bundles of collagen fibers that formed the endomysium and the perimysium. Capillary blood vesselswere noted in the connective tissue between muscle fibers. Silver impregnation demonstrated the presence of numerousbundles of nerve fibers distributed irregularly around the muscle fibers. High-resolution scanning electron microscopyshowed that the sarcoplasm of the muscle cells consisted of bundles of myofilaments arranged longitudinally andnumerous mitochondria.

Sensory nerve endings in the rat cheek mucosa: an electron microscopic study

The sensory nerve endings of the rat cheek mucosa were studied using the transmission electron microscopy. The specimens were fixed in modified Karnovsky solution and embedded in Epon resin. The sensory nerve endings showed a central terminal axon containing numerous mitochondria, neurofilaments, microtubules and clear vesicles. The proximal part of corpuscle revealed the cytoplasmic extensions of lamellar cells and the perineural cells. The fine bundles of collagen fibers are identified in the interlamellar spaces and the external part of corpuscle. Numerous concentric lamellae showed caveolae, interlamelar spaces filled with amorphous material, desmosome-type junctions between adjacent lamellae and the inner lamellar cells and the axoplasmic membrane. These fine structures are important to recognise and understand the morphological characteristics in the oral mucosa

Scanning electron microscopy of angioarchitecture of palatine gingiva in young rabbits / Microscopia eletrônica de varredura da angioarquitetura da gengiva palatina de coelhos jovens

A angioarquitetura da gengiva palatina de coelhos jovens foi estudada utilizando-se o método de modelos de corrosão vascular. Os modelos de corrosão foram obtidos a partir da injeção de resina de baixa viscosidade (Mercox« Cl-2B) sendo, posteriormente observados ao microscópio eletrônico de varredura (MEV). A gengiva palatina apresentou áreas de diferentes disposições vasculares. Os capilares da gengiva palatina e da papila interdental emitiam diversas projeções, não detectadas, porém, no sulco gengival, onde a rede capilar mostrava-se de arranjo irregular, aplainado. Os vasos sangüíneos, nutrindo o osso alveolar, também foram observados