Ultrastructural characteristics of the gerbil pterygoid medial muscle after experimental occlusal alteration.

Ten male young adult gerbils Meriones unguiculatus weighing 55g were divided in two groups: experimental (n=5) animals submitted to exodontia of the left upper molars, and sham-operated were used as control (n=5) group. The aim of the present study was to investigate the ultrastructural effects of occlusal alteration induced by unilateral exodontia on medial pterygoid muscle. After 60 days, the animals were sacrificed by perfusion intracardially with a modified Karnovsky solution after anesthetized with overdose of urethane (3g/kg i.p.). The small samples of this muscle were fixed in 2.5% glutaraldehyde solution and post-fixed in 1% buffered osmium tetroxide solution, dehydrated in ascending concentration of ethanol, and embedded in Spurr resin. Several micrographs data showed that in this period of time, the unilateral teeth extraction was able to induce modifications on the medial pterygoid muscle fibers and capillaries at ultrastructural levels as compared to control muscles and to the ones in the contralateral side of the experimental animals. Ultrastructural changes suggest that injury was greater in the hypofunctional muscle, ipsilateral to teeth extraction.

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% 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.

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.

Three-dimensional characteristics of submandibular salivary gland of ageing rats: an HRSEM study.

The characteristics of the submandibular glands of ageing Wistar rats were studied using light and high-resolution scanning electron microscopy (HRSEM) methods. For light microscopy, the samples were fixed in Bouin solution and embedded in paraffin. Sections were stained with hematoxilin-eosin and Azo-Carmin. For conventional scanning electron microscopy, the tissues were fixed in modified Karnovsky solution, and treated with NaOH solution for 3-4 days. The O-D-O method was used for HRSEM. The samples were fixed in 2% osmium tetroxide, macerated in diluted osmium and dehydrated in an increasing series of ethanol. The samples were dried in a critical point dryer, coated with gold-palladium and examined in a Hitachi high-resolution scanning electron microscope, S-900. The results showed that submandibular glands with lobules are separated by connective tissue septum. The acinar formations and the ducts, revealing the serous and mucous cells were observed. After fracture in liquid nitrogen and treatment with NaOH solution to remove the cellular components, the original disposition of the collagen bundles fibers were revealed corresponding to the round, oval or irregular acinar and ductal structures. In the cytoplasm, organelles such as mitochondria, rough endoplasmic reticulum, Golgi apparatus and serous and mucous secretory granules were observed localized in the apical portion in three-dimensional HRSEM images. The serous secretory granules presented different sizes and shapes showing the modifications which occurred in the ageing rats. The striated duct cells revealed the presence of the secretory cells and mitochondria in parallel disposition. The mitochondrial cristae were noted in three-dimensional aspects. The lumen presented numerous cytoplasmic microprojections. The lumen of excretor ducts are covered by polygonal epithelial cells containing numerous microplicae.

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.

Scanning electron microscopy of the rat tongue mucosa with special attention to bacteria on epithelial cell membranes / Microscopia eletrônica de varredura da mucosa da língua de ratos com enfoque em bactérias em menbranas de células epiteliais

The authors examined the filiform and fungiform papillae surfaces of rat tongue by scanning electron microscopy showing the numerous groupings of bacteria on the epithelial cell membranes. The fungiform papillae were round in shape and presented few bacteria. The epithelial cell of filiform papillae revealed numerous streptococci. The grouping of the bacteria are attached on the epithelial cell membrane, demonstrating three-dimensional SEM images