No abstract

The research deals with new scanning electron microscopic evaluations of the interface between blood and explanted temporary vena cava filters from patients affected by blood disorders. The biological tissues adherent to the filter and the small thrombi formed in vivo were detached from the metallic structure of the device, fixed, dehydrated and prepared for the histological and the electron microscopy. The analyses showed that both samples (thrombus and newly formed tissue) contained foreign, in some cases nano-sized, bodies. The chemistry of these particles was different and varied, and unusual compounds containing non-biocompatible elements like bismuth, lead, wolfram, tungsten were also detected. The interaction between these debris travelling in the blood stream and the blood itself leads to suspect that the formation of the thrombus can originate from these inorganic and inert foreign bodies that act as triggering agent of the blood coagulation.

A European project called "Nanopathology" allowed to develop a new diagnostic tool through which the presence of inorganic particulate matter in pathological human tissues of the digestive tract could be shown. This unexpected evidence induced the authors to put forward the hypothesis that that sort of contamination was present in ingested food. In order to demonstrate this hypothesis, 86 samples of wheat bread and 49 of wheat biscuits from 14 different countries were analyzed by means of an Environmental Scanning Electron Microscopy to detect inorganic, micro-, and nano-scaled contaminants. The X-ray microprobe of an Energy Dispersion Spectroscope was employed to identify their chemical composition. The results indicate that 40% of the samples analyzed contained foreign bodies as ceramic and metallic debris of probable environmental or industrial origin. Because of the great variety of chemical composition of the particulate matter, those contaminants were listed according to the most expressed element. The majority of these debris are not biodegradable, some are chemically toxic, and none of them have any nutritive value. The work discusses the possible origin of such a pollution and the role that it can play on human life.

During larval development of Salamandra salamandra salamandra chromatophores organize to form the definitive pigment pattern constituted by a black background with yellow patches that are characterized by epidermal xanthophores and dermal iridophores. Simultaneously the dermis undergoes remodeling from the larval stage to that typical of the adult. In the present study we ultrastucturally and immunocytochemically examined skin fragments of S. s. salamandra larvae and juveniles in order to investigate the modalities of xanthophore migration and differentiation in the context of dermal remodeling from the larval to adult stage. Semithin and thin sections showed that the dermis in newly born larvae consists of a compact connective tissue (basement lamella), to which fibroblasts and xanthophores adhere, and of a loose deep collagen layer. As larval development proceeds, fibroblasts and xanthophores invade the basement lamella, skin glands develop and the adult dermis forms. At metamorphosis, xanthophores reach the epidermis crossing through the basal lamina. We examined immunocytochemically the expression of signal molecules, such as fibronectin, vitronectin, beta1-integrin, chondroitin sulfate, E-cadherin, N-cadherin and plasminogen activator, which are known to be involved in regulating morphogenetic events. Their role in dermal remodeling and in pigment pattern formation is discussed.

Morphological, cytological and transport properties of the integument of Salamandra salamandra were investigated during natural ontogenetic development, from birth to adult. Three stages were operationally defined: I, larvae, from birth to metamorphosis; II, metamorphosis (judged externally by the colour change and loss of the gills); and III, post-metamorphosis to adult. Pieces of skin were fixed at various stages for immunocytochemical examinations, and the electrical properties were investigated on parallel pieces. Distinct cellular changes take place in the skin during metamorphosis, and lectin (PNA, WGA and ConA) binding indicates profound changes in glycoprotein composition of cell membranes, following metamorphosis. Band 3 and carbonic anhydrase I (CA I) were confined to mitochondria-rich (MR)-like cells, and were detected only in the larval stage. CA II on the other hand, was detected both in MR-like and in MR cells following metamorphosis. The electrical studies show that the skin becomes more tight (transepithelial resistance increases) upon metamorphosis, followed by manifestation of amiloride-sensitive short-circuit current (I(SC)) indicating that functional Na+ uptake has been acquired. The skin of metamorphosed adults had no finite transepithelial Cl- conductance, and band 3 was not detected in its MR cells. The functional properties of MR-like and MR cells remain to be established.