Ethical Issues in the Use of Suboptimal Kidneys for Transplants: An Italian Point of View

The shortage of organs leads to the need for utilizing suboptimal kidneys for transplantation. The distinction between optimal, marginal, and suboptimal kidneys leads surgeons to face not only technical problems but also ethical and legal issues related to clinical advantages offered by the transplant of a nonstandard kidney and the acquisition of consent. Between 1999 and 2015, we performed 658 transplants, 49 (7.5%) using suboptimal kidneys. All patients were alive and with vital graft throughout follow-up. We did not encounter any major surgical complications. From a technical point of view, our experience and literature review confirm that transplant of suboptimal kidney leads to good clinical results but exposes patients to a increased risks of surgical complications. Therefore, these interventions must take place in hospitals fully prepared for this type of surgery and performed by experienced transplant surgeons with proper matching between organ and recipient. Considering the insufficient resources available, from an ethical and legal point of view, doctors play an essential role in optimizing the use of these kidneys by avoiding wastage of organs, ensuring that transplants are done in suitable patients, and that patients are fully informed and aware of the risks and benefits associated with the specific suboptimal kidney being transplanted. We believe that, in highly specialized centers, the number of suboptimal kidney transplants should be increased, as their use has shown good clinical results and carries fewer ethical issues compared with marginal kidneys. Further, suboptimal kidneys may also be proposed for use in young patients with end-stage renal disease.

Fine structure of healthy human gingival mast cells and their immunological characterization

Despite the great number of studies on mast cell population, at the present time few are the studies regarding the structural aspects of mast cells in human gingiva. In order to identify and characterize gingival mast cells, specimens of healthy human gingival tissue have been studied. Subsequently, in order to test mast cell capability of express TNF-alfa, samples of healthy gingiva with antibody anti-TNF-alfa have been incubated. The results showed that in human gingiva mast cells are numerous and ubiquitarious. These cells exhibit several morphological types of cytoplasmic granules with characteristic subgranular content, varying in shape and density. This allows to divide gingival mast cells into two different subpopulations: either cells containing granules with compact coiled scrolls and/or particles and cells showing granules with scrolls and thin parallel bands. The two ultrastructural aspects observed seem to be correlated to the McT (mast cells containing tryptase) and McTC (mast cells containing tryptase and chymase) described in international literature, differing for ultrastructural aspect, biochemical content and response to secretagogue substances. The positivity of the reaction for TNF-alfa seems indeed to confirm that gingival mast cells are able to secrete sensible amounts of TNF-alfa.

Ultrastructural aspects of two different mast cell populations in human healthy gingival tissue

The results of our recent microscopy studies clearly have demonstrated the constant presence of numerous metachromatic cells in healthy human gingival connective tissue. Despite the great number of studies on mast cell population in many human organs (lung, skin, uterus, and bowel), at the present time few are the studies regarding the morphostructural aspects of mast cells in the human gingiva. The aim of this study was to assess by transmission electron microscopy the presence of mast cells in the healthy human gingiva and to characterize the ultrastructural aspects of mast cells populations. 30 specimens of human gingival tissue were collected from 30 patients with informed consent. The samples were prepared for T.E.M. examination. In all the ultrathin sections observed we detected numerous and ubiquitarious mast cells. These exhibited several morphological types of cytoplasmic granules with characteristic subgranular architectural variety in shape and density. This allowed us to divide mast cells into two groups: cells with granules consisted of compact coiled scrolls, fine granular material and lattice--grafting configuration, and cells containing granules with discrete scrolls formed by more concentric lamellae and particulate structure. The two ultrastructural aspects observed correspond to McTC and McT of the international literature. Therefore in the human gingival connective tissue, like in other organs, two types of mast cells are clearly present. Surprisingly, the human gingival tissue shows, like the lung, McT as the prevailing subpopulation, in contrast to the skin, uterus and gastrointestinal submucosa where McTC prevail.

[Enamel pearls: the ultrastructural aspects and morphogenesis hypotheses]

Five enamel pearls were examined by scanning electron microscope. Some external pearls presented a bare enamel surface, others were covered by a thin layer of cementum. The enamel pearls showed irregular dystrophic enamel surface or a thin layer without structure, rows of irregular Tome's processes pits, enamel caps and focal holes. Some enamel pearls revealed little areas of enamel surface resorption like-resorbing lacunae with, in some cases, areas of tissue repair.

[In vivo and in vitro biocompatibility tests of endodontic cements]

The major goal endodontic therapy has been achieved by condensing filling materials into the root canal. It's not uncommon to find excess material into the periapical tissue. It therefore becomes obligatory to use fillings materials that have acceptable biocompatibility. The purpose of this investigation was to obtain a "toxicity profile" of some endodontics materials and to compare our observations to results present in literature. The gutta-percha and five endodontic filling cements were tested "in vivo" and "in vitro". The in vivo biocompatibility involved the placement of the test material in 10 mm. Teflon tubes with an outer diameter of 1.3 mm which were implanted subcutaneously into rats. The implants were left in situ for periods of 30 and 90 days. The "hemolysis test" is designed for "in vitro" evaluations. The histological examination showed different intensity and extent cellular responses. In some cases severe infiltration of inflammatory cell and areas with necrotic were seen. At conclusion, the endodontics material evaluated showed slight, moderate and severe reactions; therefore a different pattern in tissue response.