Armanda Pugnaloni

Reconstruction of parodontal tissue with chitosan

Chitosan ascorbate, obtained by mixing chitosan with ascorbic acid and sodium ascorbate, was produced in a gel form suitable for the treatment of periodontitis according to current dental surgery. While chitosan ascorbate underwent degradation in vitro, especially in the presence of atmospheric oxygen and at pH 6.0, the protection from oxygen offered by the surgical cements and the physiological pH value permitted chitosan ascorbate to play an important biological role in vivo, where it kept a honeycomb structure, as indicated by SEM on biopsies taken on 10 patients. The proliferation and organization of the cells were thus favoured with a subsequent enhanced capability of reconstructing a histoarchitectural tissue. Chitosan was progressively reabsorbed by the host, with very satisfactory clinical recoveries of the 52 defects treated, for which tooth mobility and pocket depths were significantly reduced.

Osteoconductive properties of methylpyrrolidinone chitosan in an animal model

Bone defects were surgically produced in the tibiae of rabbits and medicated with freeze-dried methylpyrrolidinone chitosan. Histological observations 60 d after surgery showed a considerable presence of neoformed bone tissue, as opposed to controls, originating from the pre-existing bone as well as from the periosteum. The cationic nature and the chelating ability of the methylpyrrolidinone chitosan apparently favoured mineralization. Endosteal-periosteal and bone marrow osteoblast-like precursors, stimulated by growth factors entrapped in the coagulum-polysaccharide mixture, gave rise to intramembranous bone formation. The ultrastructural examination evidenced that bone osteoid was followed by mineralization of the tissue.

Vascular endothelial growth factor expression and capillary architecture in high-grade PIN and prostate cancer in untreated and androgen-ablated patients.

Recent studies have demonstrated that angiogenesis is a potent prognostic indicator for patients with prostate cancer (PCa) and have pointed out that the evaluation of vascular endothelial growth factor (VEGF) is useful in assessing the angiogenic phenotype in PCa. The aim of the study was to investigate immunohistochemically the expression of VEGF and its correlation with the pattern of capillary architecture in prostate cancer and high‐grade prostatic intraepithelial neoplasia (PIN), in untreated and androgen‐ablated patients.

Involvement of E‐cadherin, β‐catenin, Cdc42 and CXCR4 in the progression and prognosis of cutaneous melanoma

Background  A key event in cancer metastasis is the migration of tumour cells from their original location to a secondary site. The development of melanoma may be viewed as a consequence of the disruption of homeostatic mechanisms in the skin of the original site.

Decrease of rotenone inhibition is a sensitive parameter of complex I damage in brain non-synaptic mitochondria of aged rats

We investigated NADH oxidation in non‐synaptic and synaptic mitochondria from brain cortex of 4‐ and 24‐month‐old rats. The NADH oxidase activity was significantly lower in non‐synaptic mitochondria from aged rats; we also found a significant decrease of sensitivity of NADH oxidation to the specific Complex I inhibitor, rotenone. Since the rotenone‐binding site encompasses Complex I subunits encoded by mtDNA, these results are in accordance with the mitochondrial theory of aging, whereby somatic mtDNA mutations are at the basis of cellular senescence. Accordingly, a 5 kb deletion was detected only in the cortex of the aged animals.

Φm46.1, the Main Streptococcus pyogenes Element Carrying mef(A) and tet(O) Genes

ABSTRACT Φm46.1, the recognized representative of the most common variant of mobile, prophage-associated genetic elements carrying resistance genes mef(A) (which confers efflux-mediated erythromycin resistance) and tet(O) (which confers tetracycline resistance) in Streptococcus pyogenes, was fully characterized. Sequencing of the Φm46.1 genome (55,172 bp) demonstrated a modular organization typical of tailed bacteriophages. Electron microscopic analysis of mitomycin-induced Φm46.1 revealed phage particles with the distinctive icosahedral head and tail morphology of the Siphoviridae family. The chromosome integration site was within a 23S rRNA uracil methyltransferase gene. BLASTP analysis revealed that the proteins of Φm46.1 had high levels of amino acid sequence similarity to the amino acid sequences of proteins from other prophages, especially Φ10394.4 of S. pyogenes and λSa04 of S. agalactiae. Phage DNA was present in the host cell both as a prophage and as free circular DNA. The lysogeny module appears to have been split due to the insertion of a segment containing tet(O) (from integrated conjugative element 2096-RD.2) and mef(A) (from a Tn1207.1-like transposon) into the unintegrated phage DNA. The phage attachment sequence lies in the region between tet(O) and mef(A) in the unintegrated form. Thus, whereas in this form tet(O) is ∼5.5 kb upstream of mef(A), in the integrated form, tet(O), which lies close to the right end of the prophage, is ∼46.3 kb downstream of mef(A), which lies close to the left end of the prophage.

Expression of Vascular Endothelial Growth Factor Related to 72-Kilodalton Metalloproteinase Immunostaining in Patients with Serous Ovarian Tumors

The aim of the current study was to investigate the expression of vascular endothelial growth factor (VEGF) by neoplastic cells in patients with serous ovarian tumors. The correlation between neoangiogenesis and 72‐kilodalton metalloproteinase (MMP2) immunostaining also was evaluated.

Potential Role of Culture Mediums for Successful Isolation and Neuronal Differentiation of Amniotic Fluid Stem Cells

In recent years, the use of stem cells has generated increasing interest in regenerative medicine and cancer therapies. The most potent stem cells derive from the inner cell mass during embryonic development and their use yields serious ethical and methodological problems. Recently, a number of reports suggests that another suitable source of multipotent stem cells may be the amniotic fluid. Amniotic fluid mesenchymal stem cells (AFMSCs) are capable of extensive self-renewal, able to differentiate in specialized cells representative of all three germ layers, do not show ethical restriction, and display minimal risks of teratomas and a very low immunogenity. For all these reasons, amniotic fluid appears as a promising alternative source for stem cell therapy. Their recent discovery implies a lack of knowledge of their specific features as well as the existence of a protocol universally recognized as the most suitable for their isolation, growth and long-term conservation. In this study, we isolated stem cells from six amniotic fluids; these cells were cultured with three different culture mediums [Mesenchymal Stem Cell Medium (MSCGM), PC-1 and RPMI-1640], characterized by cytofluorimetric analysis, and then either frozen or induced to neuronal differentiation. Even if the immunophenotype seemed not to be influenced by culture medium (all six samples cultured in the above-mentioned mediums expressed surface antigens commonly found on stem cells), cells showed different abilities to differentiate into neuron-like cells and to re-start the culture after short-long-term storage. Cells isolated and cultured in MSCGM showed the highest proliferation rate, and formed neuron-like cells when sub-plated with neuronal differentiation medium. Cells from PC-1, on the contrary, displayed an increased ability to re-start culture after short-long term storage. Finally, cells from RPMI-1640, even if expressing stem cells markers, were not able to differentiate in neuron-like cells. Further studies are still needed in order to assess the effective role of culture medium for a successful isolation, growth, differentiation and storage of AFMSCs, but our data underline the importance of finding a universally accepted protocol for the use of these cells.

Local rh-VEGF administration enhances skin flap survival more than other types of rh-VEGF administration: a clinical, morphological and immunohistochemical study.

Abstract:  The aim of the present study was to evaluate experimentally whether administration of recombinant (rh) vascular endothelial growth factor (VEGF) can protect skin flaps from necrosis and to study the optimum mode of rh‐VEGF administration. We used rats to study the effects of local or systemic administration of rh‐VEGF on skin flap during surgery; we also tested preoperative systemic administration of rh‐VEGF to assess whether it may prepare the tissue to respond to the hypoxic injury better than previously tested methods. The animals were 30 male Sprague‐Dawley rats. Group I rats received multiple systemic injections of rh‐VEGF in the tail artery prior to flap dissection. Group II rats were injected with rh‐VEGF in the clamped left epigastric artery during flap dissection; in this group, the left flaps thus received rh‐VEGF locally (via incubation for 10 min during hypoxia) and the right flaps systemically, after blood flow restoration. Group III received saline solution instead of VEGF in the same way as group II. Skin samples from the distal portion of the flaps were collected on day 7 for morphological and immunohistochemical analysis. The flaps exhibiting the least necrosis were those treated with local rh‐VEGF, followed by those treated with systemic rh‐VEGF. The flaps that received rh‐VEGF locally showed a strong VEGF expression on keratinocytes and endothelial cells, the greatest amount of mature and newly formed vessels and strong survivin expression in endothelial cells. Local rh‐VEGF administration should thus be considered as an effective therapeutic option to enhance the survival of a tissue at risk for perfusion.

Morphological study of the capsular organization around tissue expanders coated with N-carboxybutyl chitosan

Expanders coated with N-carboxybutyl chitosan were inserted into surgical wounds in the dorsal skin of rabbits and the formation of capsular tissue was studied by scanning electron microscopy and transmission electron microscopy. N-carboxybutyl chitosan, in the course of the capsular organization, favours and potentiates the correct proliferation and organization of the tissue, rather than sustaining reactive processes leading to scar formation. N-carboxybutyl chitosan stimulates physiologically the tissue repair process and favours angiogenesis, whilst depressing fibrogenesis to a certain extent. Applications are envisaged in the treatment of wounds and in plastic surgery.