Concomitant human infections with 2 cowpox virus strains in related cases, France, 2011.

We investigated 4 related human cases of cowpox virus infection reported in France during 2011. Three patients were infected by the same strain, probably transmitted by imported pet rats, and the fourth patient was infected by another strain. The 2 strains were genetically related to viruses previously isolated from humans with cowpox infection in Europe.

Eukaryotic DING proteins are endogenous: an immunohistological study in mouse tissues.

Background: DING proteins encompass an intriguing protein family first characterized by their conserved N-terminal sequences. Some of these proteins seem to have key roles in various human diseases, e.g.

Reconstituted human gingival epithelium: nonsubmerged in vitro model.

Many studies have shown that human gingival keratinocytes grown in submerged culture fail to attain optimal differentiation. This study reports an in vitro culture system for oral gingival epithelial cells, in which they are grown at the air-liquid interface, on polycarbonate inserts, in the presence of an NIH-3T3 feeder layer. This model was compared with two submerged culture methods for gingival keratinocytes, on type 1 collagen gel and on an NIH-3T3 feeder layer.

An in vitro model of human dental pulp repair.

Pulp tissue responds to dentin injury by laying down reactionary dentin secreted by existing odontoblasts or reparative dentin elaborated by odontoblast-like cells that differentiated from precursor cells in the absence of inner dental epithelium and basement membrane. Furthermore, growth factors or active dentin matrix components are fundamental signals involved in odontoblast differentiation. In vitro, dental pulp cells cultured under various conditions are able to express typical markers of differentiation, but no culture system can re-create pulp response to dentin drilling.

Immunocytochemical localization of fibronectin and a 165-kDa membrane protein in the odontoblast layer under initial carious lesions in man.

The possible role of fibronectin in dental tissue repair was investigated by comparing its distribution and that of the 165-kDa fibronectin-binding membrane protein (165 kDa-FnBP) in odontoblasts underlying carious and sound dentine. By immunoperoxidase and light microscopy, fibronectin was localized in the dentine underlying the carious lesion, mainly on the surface of the tubule walls, whereas it could not be detected in neighbouring sound zones. The antibody to the 165 kDa-FnBP strongly reacted with the membrane of odontoblasts underlying the lesion, although those facing sound dentine did not express this antigen.

Immunohistochemical localization of L-type calcium channels in the developing first molar of the rat during odontoblast differentiation.

To study the presence of L-type calcium channels during the different steps of odontoblast differentiation, a specific monoclonal antibody against 1,4-dihydropyridine receptors was used in combination with avidin-biotin-peroxidase complex labelling. Staining was seen on the cell bodies of pre-odontoblasts, concentrated at the apical pole (distal portion) of functional odontoblasts and localized on cell bodies and processes of mature odontoblasts. Thus calcium channels were expressed at the onset of differentiation and maintained in the differentiated cells but with some changes of localization.

[Response of odontoblastic and pulpal cells to carious lesions].

The odontoblast responds to caries by the formation of sclerotic as well as reparative dentin. Sclerotic dentin is deposited during the early stages of the dentinal injury. It is characterized by the amplification of the collagen synthesis and the increase in alkaline phosphatase activity in the odontoblastic cell layer.

Odontoblast response under carious lesions.

The local regulation of odontoblast response to caries is viewed through initiation and elaboration of sclerotic as well as reparative dentin. Dentin tissue represents a multiple source of potent environment factors when teeth are affected by the demineralization phases of carious process. Some of them have already been identified in sound tissue (matrix glycoproteins, proteoglycans, growth factors, Bone Morphogenetic Protein) and may act on the cell through membrane receptors.

Immunohistochemical localization of nerve growth factor (NGF) and NGF receptor (NGF-R) in the developing first molar tooth of the rat.

Nerve growth factor (NGF) is a well established target-derived trophic factor supporting sympathetic and sensory innervation in the peripheral tissues as well as cholinergic innervation in the brain. Despite its name, NGF may have broader biological functions early in development in a wide range of non-neuronal differentiating cells. The many effects of NGF are directly dependent on initial binding of NGF to specific plasma membrane receptors on target cells.

Immunoblotting and cytochemical characterization of human enamel proteins.

Mature enamel proteins (tuft proteins) and fetal enamel proteins were extracted by an homogenizing buffer method, subjected to SDS-PAGE and immunoblotted with a polyclonal antibody raised against the mature enamel proteins. Both fetal and tuft proteins were recognized by this immunoblotting. With the same antibody, immunolocalization of the developing enamel proteins was done on semi-thin-sections of human fetal tissue at the secretory stage, using an immunoperoxidase technique.

Morphological and immunocytochemical characterization of cultured rat incisor cervical epithelial cells.

Epithelial cells from the cervical loop of the rat incisor were isolated by co-culture of apical explants with growth-arrested 3T3 fibroblasts. The epithelial phenotype of the expanding outgrowths was confirmed 10 days after the seeding of the explants by phase-contrast microscopy and immunocytochemical identification of cytokeratins. After 3 weeks in culture, the epithelial cells covered the entire surface of the coverslips and were then passaged.

[Histological aspects of tooth bleaching technics].

The chemical principles of tooth bleaching are detailed in order to analyze scanning microscopy data obtained following internal and external bleaching tooth bleaching appears harmless to the enamel structure providing no etching is applied prior to bleaching. Previous enamel undermining appears to increase the porosity along preexisting cracks. Internal bleaching gives way to enamel and dentinal demineralization, which is of particular importance at the dento enamel junction.

In vitro mineralization of a three-dimensional collagen matrix by human dental pulp cells in the presence of chondroitin sulphate.

These matrices were used as cell culture substrates to investigate the influence of extracellular molecules on mineralization. Pulp cells seeded in type I collagen or type I collagen-chondroitin-4-sulphate sponges were able to grow and were morphologically similar to cells responsible for reparative dentine formation in vivo. In sponges consisting of collagen only, the cells elaborated an abundant new matrix which became organized with time and consisted of collagen fibres surrounded by fibrillar material, but no mineralization was observed.

Cytokeratins as molecular markers in the evaluation of the precise differentiation stage of human gingival epithelium reconstituted in vitro.

Cytokeratins are considered to be molecular markers for different types of epithelial differentiation. They were used to investigate the precise differentiation stage of gingival epithelium, reconstituted in vitro, following two different culture procedures. Human trypsin-dissociated gingival keratinocytes were seeded either on a feeder layer of irradiated mouse 3T3 fibroblasts or on a connective tissue equivalent (lattice) made up of human fibroblasts in a collagen gel.

[Use of human epithelial cultures in mucogingival surgery].

A clinical technique utilizing autologous cultured epithelial cells in vestibule deepening operations is described. Epithelial cells from oral mucosa were grown in tissue culture on a feeder layer, released from their flasks and placed with the basal side up on the recipient beds. The cultured cells induced rapid healing of the wound, which was free of pain and contractions.

Localization of 28 kDa calbindin in human odontoblasts.

The presence of 28 kDa calbindin in human odontoblasts was studied by use of specific antibodies raised against chick duodenal 28 kDa calbindin, in immunofluorescence, immuno-peroxidase, and electron-microscopic labelling experiments. The calbindin-like protein was detected mainly in the cytoplasm of odontoblast cell bodies, in their processes and occasionally in their nuclei. Correspondingly, at the ultrastructural level, immunoreactive material was associated with the cytosol, microfilaments and cilia.

Trichomonas tenax: ultrastructure of giant forms.

Trichomonas tenax is a parasitic flagellate of the human mouth. The morphology and the ultrastructure of the protozoan are identical to those of other trichomonads. Giant forms suddenly appeared in a strain maintained in culture for two years.

Localization and synthesis of type III collagen and fibronectin in human reparative dentine. Immunoperoxidase and immunogold staining.

The injury of dental pulp tissue, following caries, is accompanied by the deposit of a typical hard scar tissue known as reparative dentine which should be regarded as the mineralization of a new organic matrix. Highly purified antibodies were used in combination with immunoperoxidase or immunogold technique at the ultrastructural level to reveal the distribution and synthesis of types I and III collagen and fibronectin elaborated by typical matrix-forming cells in the new tissue. Specific immunoperoxidase labelling, on demineralized teeth, clearly demonstrated that type I collagen represents the main type of collagen (88%).

Type-I collagen production by human odontoblast-like cells in explants cultured on cyanoacrylate films. Electron-immunolocalization of fibronectin at cell/film interface.

Odontoblast-like cells derived from human tooth pulps were maintained in explant culture and grown either on glass coverslips only (used as control) or on glass coverslips coated with cyanoacrylate films. Ultrastructural and cyto-morphometric evidence showed that cells exposed to cyanoacrylate, in contrast to controls, display a significant decrease of rough endoplasmic reticulum and mitochondria. In addition, immunofluorescent staining and radioimmunoassays for type-I collagen suggested disturbances in production for the exposed cells.

Influence of fixative on the fine structure of mouse odontoblasts: a study on undemineralized tissue.

The present report describes techniques of fixation and embedding suitable for studying the fine structure of odontoblasts without demineralization. The quality of the procedures employed was verified by comparing the ultrastructural preservation of the odontoblasts prepared by simple fixation and by the double-fixation method. Simple fixation by immersion in osmium tetroxide in vacuum preserves the longitudinal arrangement of the rough endoplasmic reticulum and Golgi apparatus, showing various vesicles which often contain filamentous threads of weak electron density aligned in parallel at repeating intervals typical of odontoblastic cells.

Intercellular junctions in human tooth-pulp cells in culture in vitro revealed by freeze-fracture, lanthanum impregnation and filipin treatment.

Three kinds of intercellular junctions were detected between human dental pulp cells in explant culture with electron microscopy included filipin detection for cholesterol; desmosome-like junctions observed on ultrathin sections probably contribute to the cohesiveness between cells in culture. Gap junctions, responsible for intercellular communication, exhibited two morphologies on freeze-fracture replicas: a conventional arrangement of their intramembranous particles and a crystalline array corresponding to the formation stage of junctions. Primitive tight junctions were detected on freeze-fracture replicas but not on ultrathin sections.

Filtration pressure and red blood cell deformability: evaluation of a new device: erythrometre.

The authors have tested a new device that records the filtration pressure of a suspension of red blood cells (R.B.C.