Biomedical subjects

M Canfora

Publications and source records attributed to M Canfora.

5 recordsLinked to original sources

PubMed2000

Role of noise in image processing by the human perceptive system.

Two psychophysics experiments are described, pointing out the significant role played by stochastic resonance in recognition of capital stylized noisy letters by the human perceptive apparatus. The first experiment shows that an optimal noise level exists at which the letter is recognized for a minimum threshold contrast. A simple two-parameter model that best fits the experimental data is also discussed. In the second experiment we show that a dramatically increased ability of the visual system in letter recognition occurs in an extremely narrow range of increasing noise. Possible interesting future investigations suggested by these experimental results and based on functional imaging techniques are discussed.

Brain↗

PubMed1998

[Physiopathology of beta and gamma catenin expression in the oral epithelium].

BACKGROUND: Catenins belong to a family of proteins that mediate the binding between intracytoplasmic domain of cadherins and cytoskeleton. Few data on distribution of beta and gamma catenins in non-neoplastic tissues are available from current literature. This study aims to evaluate distribution of beta and gamma catenins in oral epithelium. METHODS: Nine formalin-fixed and paraffin-embedded samples of oral epithelium were retrieved from files of Department of Oral Pathology of the University of Naples "Federico II". These samples were tested with anti-beta and anti-gamma monoclonal antibodies revealed by standard streptavidin-biotin-peroxidase technique. Sections have been evaluated by two observers by optical microscope using a 40X objective. The number of positive cells has been evaluated using a semi-quantitative method. RESULTS: The results of this study show that beta and gamma catenins were mostly distributed in the upper two-thirds of oral epithelial thickness, except for keratinized areas which appear negative. Basal layer is positive except for the basal side of basal cells. Keratinized layers are negative for beta and gamma catenins. CONCLUSIONS: In physiologic conditions staining pattern for beta and gamma catenins is almost exclusively membranous, sometimes cytoplasmic but never nuclear. This staining is well-represented even in conditions of chronic inflammation and leucoplakia.

Cadherins↗

PubMed1996

[The role of syndecan and tenascine during tooth development. Review o the literature].

Morphogenesis and cell differentiation in the developing tooth are controlled by a series of reciprocal interactions between the epithelial and mesenchymal tissues. The exact molecular mechanisms operating in these interactions are unknown at present, but both structural components of the extracellular matrix and cellular receptors have been suggested to be involved. In this review we resume our knowledge about tenascin and syndecan distribution and activity.

Cell Differentiation↗

PubMed1991

Factors affecting variations in pulmonary diffusing capacity resulting from postural changes.

The relation of postural changes to the diffusing capacity of the lung for carbon monoxide (DLCO) was investigated in 12 normal nonsmokers in order to evaluate the influence of body position on several components of lung resistance to gas diffusion. The well-known increase in CO diffusing capacity in the supine position was obtained only for data corrected for alveolar volume (KCO: 6.18 +/- 0.75 vs. 5.45 +/- 0.67 ml/min/mm Hg/l; p less than 0.005). Moreover, only the membrane component (Dm) increased significantly in supine subjects (KDm = 2.81 +/- 1.32 vs. 1.82 +/- 0.54 ml/min/mm Hg/l; p less than 0.05), the increase in capillary blood volume (Vc) being not significant (KVc = 12.54 +/- 4.22 vs. 11.17 +/- 3.79 ml/l; NS). These data could be interpreted as a demonstration of a more homogeneously distributed ventilation with respect to diffusion surface in healthy young people in a supine position. The amount of surface available for diffusion seems therefore to be a limiting factor to gas flow across the lungs in these subjects. Thus a straightforward attribution of posturally influenced changes in CO diffusing capacity exclusively to factors affecting Vc is not recommended, particularly in pathological conditions, if information about variation in distribution of ventilation is unavailable.

Adult↗

PubMedDate not supplied

[The distribution of intermediate filaments, histiocytic antigens and neural crest-related antigens in the adult dental pulp. An immunocytochemical approach].

MATERIALS AND METHODS: Ten human healthy teeth were extracted for orthodontic or surgical purposes and processed for histological and immunocytochemical examination with the streptavidin-biotin-peroxidase method. Highly purified antibodies were used to reveal the distribution of intermediate filaments (vimentin, desmin, alpha-smooth muscle actin), histiocytic antigens (alpha-1-antitrypsin, lysozyme), neural and neural-crest-associated antigens (neuron-specific enolase, chromogranin-A, S-100, synaptophysin, glial fibrillary acidic protein, neurofilaments) in the adult pulp tissue. RESULTS: Vimentin immunostaining was strongly positive in the network of pulpal fibroblasts. Desmin and alpha-smooth muscle actin were present only in the vessel walls. Staining for alpha-1-antitrypsin and lysozyme reveals a number of macrophage-like cells in the central portion of the pulp. Macrophages were the most dominating immunocompetent cells. Negative immunostaining for chromogranin-A demonstrated the absence of neuroendocrine antigens in the adult dental pulp. Immunostaining for neuron-specific enolase, S-100 protein, synaptophysin, glial fibrillary acidic protein and neurofilaments were positive, with different intensity, in nerve fibres, but no pulp cell was found to be immunoreactive. CONCLUSIONS: The conclusion is drawn that the lack of labelling of pulp cells by the neural associated antibodies could be due to differentiation processes during tissue development.

Adult↗