[Show abstract][Hide abstract] ABSTRACT: Kawasaki disease (KD) is a rare and often undiagnosed disease, at least in the western countries. It is characterized by an inflammatory acute febrile vasculitis of medium sized arteries with a propensity to damage the coronary arteries. It normally occurs in the early childhood and the diagnosis is based on clinical symptoms. During the progression of the disease thrombocytosis is usually detected. This can exert a pathogenetic role in the cardiovascular complications occurring in KD. In the present work peripheral blood plasma and platelets from twelve naïve patients with KD were analyzed in order to detect possible pathogenetic determinants or progression markers. Morphological, biochemical and flow cytometrical methods have been used. With respect to age-matched healthy donors, we found an increase of platelet activation markers, i.e. degranulation, phosphatidylserine (PS) externalization and leukocyte-red cell-platelet aggregates. Some significant alterations that could represent suitable diagnostic determinants have also been detected in patient plasma: (i) decreased antioxidant power, (ii) decreased levels of asymmetric dymethylarginine (ADMA), a naturally occurring chemical interfering with the production of nitric oxide, and (iii) increased levels of soluble P-Selectin and soluble annexin V. Since PS externalizing platelets are known to exert a pro-coagulant activity, our data suggest the hypothesis that increased risk of vascular complications in KD could depend on platelet stimulation and defective apoptosis probably related to nitrosative stress.
Biochemical and Biophysical Research Communications 02/2010; 392(3):426-30. · 2.41 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Changes in the mitochondrial membrane potential play a key role in determining cell fate. Mitochondria membrane hyperpolarization has been found to occur after cell activation, e.g. in lymphocytes, whereas depolarization is associated with apoptosis. The aim of this study was to investigate the effects of an immunological stimulus, i.e. opsonized zymosan A, on human platelet mitochondria by means of flow and static cytometry analyses as well as biochemical methods. We found that opsonized zymosan induced significant changes of platelet morphology at early time points (90 min). This was associated with increased production of reactive oxygen species, and, intriguingly, mitochondrial membrane hyperpolarization. At a later time point (24 h), opsonized zymosan was found to induce increased expression of CD47 adhesion molecule, platelet aggregation, mitochondrial membrane depolarization and phosphatidylserine externalization. Although these late events usually represent signs of apoptosis in nucleated cells, in opsonized zymosan-treated platelets they were not associated with membrane integrity loss, changes in Bcl-2 family protein expression or caspase activation. In addition, pre-treatment with low doses of the 'mitochondriotropic' protonophore carbonyl cyanide p-(trifluoro-methoxy)phenylhydrazone counteracted mitochondrial membrane potential alterations, production of reactive oxygen species and phosphatidylserine externalization induced by opsonized zymosan. Our data suggest that mitochondrial hyperpolarization represents a key event in platelet activation and remodeling under opsonized zymosan immunological stimulation, and opsonized zymosan immunological stimulation may represent a useful tool for understanding of the pathogenetic role of platelet alterations associated with vascular complications occurring in metabolic and autoimmune diseases.
[Show abstract][Hide abstract] ABSTRACT: Anaplastic large cell lymphoma (ALCL) is characterized by preferential paracortical and intrasinusoidal lymph node involvement by large anaplastic tumor cells expressing the CD30 antigen. Up to 80% of pediatric patients with ALCL can be cured with multi-agent chemotherapeutic regimens. Patients resistant to chemotherapy or suffering from early relapse have a poor prognosis and a poor chance of survival. In these cases, the highly aggressive clinical course of ALCL, associated with systemic symptoms and extranodal involvement, has been treated with different approaches in various cooperative trials, including conventional chemotherapy and human stem cell transplantation (HSCT). However, the optimal treatment has not yet been defined, in particular in cases of relapse. More recently, radioimmunotherapy has been studied with encouraging results in cancer patients, including non-Hodgkin's lymphoma. Here we describe the case of a pediatric ALCL, relapsing after HSCT, treated with pretargeted antibody-guided radioimmunotherapy, obtaining a complete remission, with excellent quality of life over the past 10 months.
European Journal Of Haematology 10/2007; 79(3):258-62. · 2.55 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Autosomal-recessive osteopetrosis is a severe genetic disease caused by osteoclast failure. Approximately 50% of the patients harbor mutations of the ATP6i gene, encoding for the osteoclast-specific a3 subunit of V-ATPase. We found inactivating ATP6i mutations in four patients, and three of these were novel. Patients shared macrocephaly, growth retardation and optic nerve alteration, osteosclerotic and endobone patterns, and high alkaline phosphatase and parathyroid hormone levels. Bone biopsies revealed primary spongiosa lined with active osteoblasts and high numbers of tartrate-resistant acid phosphatase (TRAP)-positive, a3 subunit-negative, morphologically unremarkable osteoclasts, some of which located in shallow Howship lacunae. Scarce hematopoietic cells and abundant fibrous tissue containing TRAP-positive putative osteoclast precursors were noted. In vitro osteoclasts were a3-negative, morphologically normal, with prominent clear zones and actin rings, and TRAP activity more elevated than in control patients. Podosomes, alphaVbeta3 receptor, c-Src, and PYK2 were unremarkable. Consistent with the finding in the bone biopsies, these cells excavated pits faintly stained with toluidine blue, indicating inefficient bone resorption. Bone marrow transplantation was successful in all patients, and posttransplant osteoclasts showed rescue of a3 subunit immunoreactivity.
American Journal Of Pathology 02/2003; 162(1):57-68. · 4.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We investigated apoptosis in polymorphonuclear neutrophils (PMNs) induced by cytarabine (Ara-C). This drug increased apoptosis by 100% with respect to the controls after 3 hr of incubation. This increase was inhibited by N-acetyl-l-cysteine (NAC) or diphenyleneiodonium chloride (DPI). Ara-C alone caused an early increase (after a 30-min incubation) in intracellular oxidant generation (inhibitable by rotenone, fumonisin b1, and DPI) and in protein tyrosine phosphorylations (inhibitable by NAC). The drug also affected the observed reduction of dimethylthiazol diphenyltetrazolium bromide (MTT). No extracellular release of reactive oxygen species (ROS) was elicited by the addition of Ara-C, while the drug increased the release of ROS by N-formyl-leucyl-phenylalanine-(f-MLP) but not phorbol 12-myristate 13-acetate-stimulated PMNs. This phenomenon was abolished by the addition of genistein, whereas such an effect was not observed following the addition of 1-(5-isoquinolynilsulfonyl)-2-methylpiperazine (H7). Ara-C induced ROS release from PMNs in the presence of subthreshold concentrations of f-MLP (priming effect). These results indicate that intracellular ROS production from mitochondria promotes Ara-C-induced apoptosis. Ara-C primes plasma membranes by a mechanism involving protein tyrosine phosphorylations and may also contribute to ROS generation from the granules.
[Show abstract][Hide abstract] ABSTRACT: X-ray photoelectron spectroscopy (XPS) was used to define the chemical composition of the outermost surface layer and the surface modification of a plasma-coated phospho-silicate glass (identified as BVA) when immersed in K-phosphate buffer or in phosphate buffered human albumin solution. Its behavior was compared with that of a soda-lime-based glass (identified as BVH) treated in the same way. The surface % composition of plasma-sprayed glass was consistent with bulk composition. After incubation with buffer, a Ca-P-rich layer developed only on the surface of BVA glass. Human serum albumin was bound reversibly to both glasses maintaining its native state. However, the protein completely covered the BVA glass surface within 24 h, with the formation of a mixed albumin-Ca-P layer, while 4 days incubation was necessary for complete coverage of BVH glass surface. Murine fibroblasts seeded on plasma-coated BVA glass showed a proliferation pattern similar to that of control cells grown on Petri dish, while cells seeded on BVH had more restricted growth. A limited response was induced in polymorphonuclear granulocytes by both bulk glasses powder. In conclusion, the glass identified as BVA has the suitable characteristics of its surface layers to be considered biologically active from both a chemical and a cellular point of view.
[Show abstract][Hide abstract] ABSTRACT: Literature concerning exercise-induced platelet activation in chronic stable angina is somewhat confusing. The reason lies in the type of exercise as well as in methodological problems. A powerful, recently introduced procedure to detect platelet activation is flow cytometry. Platelet response to activating factors is mediated by calcium uptake; however, calcium antagonist effect on platelet activity is still unclear.
The study was undertaken to investigate exercise-induced platelet activation before and after treatment with amlodipine in chronic stable angina.
Twenty patients with chronic stable angina were entered into the study. Each subject underwent a symptom-limited cycloergometer stress test following a washout period of 2 weeks. Blood samples were collected before and immediately after exercise. All subjects were then randomized into two groups of 10 patients each, with Group 1 and Group 2 taking amlodipine 10 mg/day, and placebo for 4 weeks, respectively. They subsequently underwent a second exercise stress test, and blood samples were obtained before and immediately after exercise. Flow-cytometric evaluation of platelet activity was performed in order to recognize GMP-140 expression on platelet membrane.
Strenuous exercise induced a significant increase in platelet activation in all subjects prior to therapy. No significant differences were observed in platelet activity at rest between Groups 1 and 2, whereas a significant decrease in exercise-induced platelet activation was demonstrated in Group 1 compared with Group 2.
Our data provide evidence of the favorable effect of amlodipine on exercise-induced platelet activation in patients affected by chronic stable angina.
[Show abstract][Hide abstract] ABSTRACT: The search for chemical devices to be used in clinical orthopaedics must find substances that are biocompatible and do not elicit inflammatory responses in vivo. To this end, a new form of glass has been prepared, composed of 8.1% CaO, 2.9% P2O5, 6.7% N2O5 and 82.3% SiO2, using sol-gel procedures. In order to evaluate the in vitro biocompatibility of this glass, the proliferation of cultured murine fibroblasts and the activation of human polymorphonuclear leukocytes has been studied. The performance of the sol-gel glass has been compared with that of a biocompatible non-resorbable soda-lime glass. Unlike the soda-lime glass, the sol-gel glass neither caused the inhibition of fibroblast growth nor elicited a marked inflammatory response by polymorphonuclear leukocytes, as demonstrated by chemiluminescence assay for reactive oxygen metabolites.
Journal of Materials Science Materials in Medicine 08/1997; 8(7):417-21. · 2.14 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Anecdotal reports in patients with acute and chronic iron overload have recently indicated that the efficacy and safety of an alternative chelation program including intravenous and/or continuous delivery of deferoxamine (DFO) may be in contrast with the risk of developing lung injury. Production of oxygen radicals has been postulated to be an important mechanism by which polymorphonuclear leukocytes (PMNs) could cause tissue injury in patients undergoing this alternative treatment method.
PMNs obtained from healthy donors were incubated at 37 degrees C for 30 min with DFO (across the drug concentration 0.125 to 10 mg/mL). Superoxide (O2) production was measured by superoxide inhibitable cytochrome c reduction as well as by an NBT densitometric kinetic test. In the same run the effect of lipid peroxidation was demonstrated by means of a malonyl-dialdehyde (MDA) assay.
Preincubation of PMNs with any study concentration of DFO significantly enhanced O2 release as well as MDA production upon PMA stimulation. Maximal intracellular and extracellular O2-release as well as MDA production occurred at certain drug concentrations.
Our in vitro findings suggest that O2-release may be an additional detrimental contribution to tissue injury in some patients who develop pulmonary toxic effects while on intravenous and/or continuous DFO administration.
[Show abstract][Hide abstract] ABSTRACT: Human recombinant granulocyte colony-stimulating factor (rhG-CSF), widely used to combat chemotherapy-induced neutropenia, stimulates both in vivo and in vitro intra- and extra-cellular O2- production in human polymorphonuclear cells (PMNs).
Twelve patients with solid tumors or acute lymphoblastic leukemia were treated during induced aplasia with rhG-CSF (5 micrograms/kg/day). Intra- and extracellular O2- production by PMNs isolated from these patients after 5 days of rhG-CSF therapy was assessed following both fMLP and PMA stimulation.
All patients showed a rise in PMN count; administration of rhG-CSF enhanced intra- and extracellular O2- release after fMLP but not after PMA stimulation.
rhG-CSF potentiates in vivo O2- production by PMNs stimulated with receptor-mediated agonists via G-protein (e.g. fMLP), but not by those stimulated with agonists that bypass receptors via protein kinase C (e.g. PMA).