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The thymus plays a key role in myasthenia gravis (MG), a B cell-mediated autoimmune disorder affecting neuromuscular junction. Most MG patients have thymic abnormalities, including hyperplasia and thymoma, a neoplasm of thymic epithelial cells. Epstein-Barr virus (EBV) is associated with autoimmune diseases and tumors. Recently, we showed EBV persistence and reactivation in hyperplastic MG thymuses, suggesting that EBV might contribute to intra-thymic B cell dysregulation in MG patients. Here, we investigated EBV involvement in thymoma-associated MG, by searching for EBV markers in MG (n=26) and non-MG (n=14) thymomas. EBV DNA and EBV-encoded small nuclear RNA (EBER) 1 transcript were detected in 14/26 (53.8%) and 22/26 (84.6%) MG thymomas, and only in 3 of 14 (21.4%) non-MG thymomas. Latent EBNA2 and late gp350/220 lytic transcripts were undetectable in all, but one, thymomas, and early lytic BZLF1 transcript was absent in all samples, suggesting that early infection events and EBV reactivation were very rare in thymomas. EBER1 and 2-positive cells were detected in MG, but not in non-MG, thymomas, as well as cells expressing EBV latency proteins (EBNA1, LMP1, LMP2A), that were mainly of B cell phenotype, indicating EBV association with MG rather than with thymoma. Toll-like receptor (TLR) 3 transcriptional levels were higher in MG than non-MG thymomas and positively correlated with EBER1 levels, suggesting a role for EBERs in TLR3 activation. Our findings show that EBV is commonly present in thymoma-infiltrating B cells of myasthenic patients, indicating a contribution of EBV to B cell-mediated autoreactivity in MG associated with thymic tumor., Competing Interests: CONFLICTS OF INTEREST The authors declare that no conflicts of interest exist.

Blunt colorectal traumas are rare clinical entities with a challenging diagnostic and operative management. We describe the case of a 40-year-old man, victim of an accidental fall from a height of four meters who was subsequently diagnosed to have a blunt rectal trauma. A first CT scan showed fracture of the skull and an extensive subcutaneous haematoma of the lower back associated with a fracture of the left transverse processes of lumbar vertebrae. No other visceral abdominal lesions were recognized and patient was admitted to our department for observational studies. After 48 hours from admission the patient presented a subcutaneous emphysema suspicious for hollow viscus injuries. A digital rectal examination detected a laceration both of the posterior rectal wall and the superior anal margin. The patient was successfully managed with spur colostomy, transanal evacuation of the retroperitoneal haematoma and primary repair of both the sphincteric muscle and the rectal wall. As soon as the patient achieved full recovery we performed a reversal colostomy. Diagnosis and management of rectal blunt trauma is still a matter of debate and no definitive recommendation treatments are available. The surgical treatment should be tailored on patient medical conditions and clinicians should maintain a high index of suspicious because a delay in diagnosis can result in higher morbidity and mortality rate., Key Words: Colorectal blunt injury, Colostomy, Laparoscopy, Trauma.

Unlabelled: Lung cancer is the most common neoplasm diagnosed worldwide. Metastatic presentation of the disease is frequent. Apart from the usual sites of metastatic disease (bone, adrenals, liver, brain), a particular site for metastases is represented by skin. The case we report is about a 66 year-old man with cutaneous metastasis from lung cancer. A 66 year-old man, with a previous history of abdominal aortic aneurism, chronic obstructive pulmonary disease, cardiopathy, diabetes mellitus, was admitted to our institution for left lower lobe lung cancer. After accurate preoperative staging, patient underwent a thoracotomic left lower lobectomy. Histological examination revealed a squamocellular carcinoma: G2-3, pT2bN0. Patient underwent oncological evaluation for the scheduled follow up. After 6 months patient went back to our observation for the appearance of a skin nodule, firm, dischromic, painful and ulcerated, localized in right iliac fossa. Biopsies demonstrated the nodule to be squamocellular carcinoma. Patient underwent a CT scan of the abdomen and thorax, which revealed the absence of infiltration of the deep fascial and muscular planes by the neoplasm. Patient underwent surgical removal of the lesion. Final histological examination confirmed the lesion to be metastasis of squamocellular lung cancer. Metastases from lung cancer occur in about 2,5-7,5% of cases. Median survival for these patients is 2,9 months. The most common type of neoplasm, according to Japanese Authors, is adenocarcinoma followed by squamocellular carcinoma. Some studies demonstrated the adequacy of surgery followed by chemotherapy, in case of single lesion. In case of multiple cutaneous metastases, many Authors suggest only chemotherapy, although the ideal scheme hasn't been discovered yet. Cutaneous metastases from lung cancer are rare; however the appearance of skin lesions, in patients with a positive oncological history, requires much attention. Accurate evaluation of the patient is paramount in choosing the adequate therapeutic algorithm., Key Words: Chemotherapy, Lung Cancer, Skin Metastases.

Myasthenia gravis (MG) is an autoimmune disease marked by weakness of voluntary musculature. Medical and surgical therapy of adult myasthenia is well documented. There is little pediatric surgical evidence, only a few case reports being available. The aim of this paper is to verify whether the surgical and anesthesiological techniques can warrant an early and safe discharge from the operating room. The secondary aim is to assess the presence of perioperative indicators that can eventually be used as predictors of postoperative care. During the years 2006-2009, 10 pediatric patients were treated according to a surgical approach based on video assisted thoracoscopic extended thymectomy (VATET). Standard preoperative evaluation is integrated with functional respiratory tests. Anesthetic induction was made with propofol and fentanyl/remifentanyl and maintenance was obtained with sevoflurane/desflurane/propofol ± remifentanyl. A muscle relaxant was used in only one patient. Right or left double-lumen bronchial tube (Rüsch Bronchopart® Carlens) placement was performed. Six patients were transferred directly to the surgical ward while 4 were discharged to the intensive care unit (ICU); ICU stay was no longer than 24 h. Length of hospital stay was 4.4±0.51 days. No patient was readmitted to the hospital and no surgical complications were reported. Volatile and intravenous anesthetics do not affect ventilator weaning, extubation or the postoperative course. Paralyzing agents are not totally contraindicated, especially if short-lasting agents are used with neuromuscular monitoring devices and new reversal drugs. Perioperative evaluation of the myasthenic patient is mandatory to assess the need for postoperative respiratory support and also predict timely extubation with early transfer to the surgical department. Availability of new drugs and of reversal drugs, the current practice of mini-invasive surgical techniques, and the availability of post anesthesia care units are the keys to the safety and successful prognosis of patients affected by MG who undergo thymectomy.

Objective: Microvesicles (MVs) have been indicated as important mediators of intercellular communication and are emerging as new biomarkers of tissue damage. Our previous data indicate that reactive microglia/macrophages release MVs in vitro. The aim of the study was to evaluate whether MVs are released by microglia/macrophages in vivo and whether their number varies in brain inflammatory conditions, such as multiple sclerosis (MS)., Methods: Electron and fluorescence microscopy and flow cytometry were used to detect myeloid MVs in the cerebrospinal fluid (CSF) of healthy controls, MS patients, and rodents affected by experimental autoimmune encephalomyelitis (EAE), the animal model of MS., Results: Myeloid MVs were detected in CSF of healthy controls. In relapsing and remitting EAE mice, the concentration of myeloid MVs in the CSF was significantly increased and closely associated with disease course. Analysis of MVs in the CSF of 28 relapsing patients and 28 patients with clinical isolated syndrome from 2 independent cohorts revealed higher levels of myeloid MVs than in 13 age-matched controls, indicating a clinical value of MVs as a companion tool to capture disease activity. Myeloid MVs were found to spread inflammatory signals both in vitro and in vivo at the site of administration; mice impaired in MV shedding were protected from EAE, suggesting a pathogenic role for MVs in the disease. Finally, FTY720, the first approved oral MS drug, significantly reduced the amount of MVs in the CSF of EAE-treated mice., Interpretation: These findings identify myeloid MVs as a marker and therapeutic target of brain inflammation., (Copyright © 2012 American Neurological Association.)

Microvesicles (MVs) released into the brain microenvironment are emerging as a novel way of cell-to-cell communication. We have recently shown that microglia, the immune cells of the brain, shed MVs upon activation but their possible role in microglia-to-neuron communication has never been explored. To investigate whether MVs affect neurotransmission, we analysed spontaneous release of glutamate in neurons exposed to MVs and found a dose-dependent increase in miniature excitatory postsynaptic current (mEPSC) frequency without changes in mEPSC amplitude. Paired-pulse recording analysis of evoked neurotransmission showed that MVs mainly act at the presynaptic site, by increasing release probability. In line with the enhancement of excitatory transmission in vitro, injection of MVs into the rat visual cortex caused an acute increase in the amplitude of field potentials evoked by visual stimuli. Stimulation of synaptic activity occurred via enhanced sphingolipid metabolism. Indeed, MVs promoted ceramide and sphingosine production in neurons, while the increase of excitatory transmission induced by MVs was prevented by pharmacological or genetic inhibition of sphingosine synthesis. These data identify microglia-derived MVs as a new mechanism by which microglia influence synaptic activity and highlight the involvement of neuronal sphingosine in this microglia-to-neuron signalling pathway.

Background: Video-assisted thoracoscopic extended thymectomy (VATET) is well established in the treatment of myasthenia gravis; however, patient selection remains controversial. Perioperative management protocol is lacking, and concerns regarding post-operative myasthenic crisis still remain. We performed a retrospective observational study evaluating the impact of the introduction of a protocol in the perioperative management of patients with myasthenia gravis who underwent VATET., Methods: The perioperative management protocol was developed by a team of neurologists and anesthesiologists who reviewed the literature and their previous experience on myasthenia gravis patients. Respiratory, clinical, and neurological patient features were included in the protocol evaluation. A retrospective review of patients who underwent VATET before and after introduction to the protocol was finally performed., Results: The medical records of 66 patients (pre-protocol group) and 44 patients (protocol group) were available for the study. In the pre-protocol group, 17 patients (26%) were admitted to intensive care unit (ICU) during the post-operative period, while three patients (6.8%) of the protocol group met the criteria for ICU post-operative admission. This resulted in a reduction of 73.5% of patients admitted to ICU (P = 0.023) and in an 80% (P = 0.002) reduction of the use neuromuscular blocking agents. Two post-operative myasthenic crises preceded by bulbar symptoms (1.8%) were identified in the pre-protocol group patients., Conclusions: Although the application of our protocol results in a substantial reduction in the recovery of patients in the ICU and in hospital costs, there was no substantial difference in mortality and morbidity between patients admitted to the surgical ward or to ICU., (© 2011 The Authors Acta Anaesthesiologica Scandinavica © 2011 The Acta Anaesthesiologica Scandinavica Foundation.)

Hepatitis B virus (HBV) produces high quantities of subviral surface antigen particles (HBsAg) which circulate in the blood outnumbering virions of about 1\10(3-6) times. In individuals coinfected with the defective hepatitis Delta virus (HDV) the small HDV-RNA-genome and Delta antigen circulate as ribonucleoprotein complexes within HBsAg subviral particles. We addressed the question whether subviral HBsAg particles may carry in the same way cellular microRNAs (miRNAs) which are released into the bloodstream within different subcellular forms such as exosomes and microvescicles. Circulating HBsAg particles were isolated from sera of 11 HBsAg carriers by selective immunoprecipitation with monoclonal anti-HBs-IgG, total RNA was extracted and human miRNAs were screened by TaqMan real-time quantitative PCR Arrays. Thirty-nine human miRNAs were found to be significantly associated with the immunoprecipitated HBsAg, as determined by both comparative DDCT analysis and non-parametric tests (Mann-Whitney, p<0.05) with respect to controls. Moreover immunoprecipitated HBsAg particles contained Ago2 protein that could be revealed in ELISA only after 0.5% NP40. HBsAg associated miRNAs were liver-specific (most frequent = miR-27a, miR-30b, miR-122, miR-126 and miR-145) as well as immune regulatory (most frequent = miR-106b and miR-223). Computationally predicted target genes of HBsAg-associated miRNAs highlighted molecular pathways dealing with host-pathogen. The finding that HBsAg particles carry selective pools of hepatocellular miRNAs opens new avenues of research to disentangle the complex interactions between host and HBV and provides a non invasive tool to study the physiopathology of liver epigenetics.

Background: To investigate if the tumour infiltrating lymphocytes (TILs) are able to predict the sentinel lymph node (SLN) positivity, the disease-free survival (DFS) and overall survival (OS) in clinical stages I-II AJCC primary cutaneous melanoma (PCM)., Methods: The study included consecutive patients with PCM, all diagnosed, treated and followed up prospectively. Logistic regression was used to investigate the association between DFS, OS, SLN positivity and Breslow thickness, Clark level, TIL, ulceration, lesion site, gender, regression and age., Results: From November 1998 to October 2008, 1251 consecutive patients with PCM were evaluated. Median age was 51 (range 15-96) with 32.2% (N=393) of them older than 60; 44.8% of them were males. Of the whole series, a total of 404 patients with primary vertical growth phase (VGP) melanoma and no clinical evidence of metastatic disease underwent SLN biopsy. Of these, 74 (18.8%) had a positive SLN. In a multivariate analysis, primary melanoma on the extremities versus that on the axial locations (truncal and head/neck) (OR 0.49, 95% CI 0.25-0.98, p 0.04) and TILs (TILs versus no TILs) (OR 0.47, 95%CI 0.25-0.90, p 0.02) were predictive for lower probability of SLN involvement, while thickness (>4mm versus 0-1mm) (OR 24, 19, 95% CI 4.91-119.13, p<.001) was predictive for higher risk of SLN positivity. A multivariate stepwise analysis confirmed these results. The histological status of the SLN was the most significant predictor of DFS and OS. Patients with a negative SLN had a 5-year DFS of 75.9%, compared with 35.2% in patients with a positive SLN (p<.0001) and a 5-year OS of 88.7% versus 42.9%, respectively (p<.0001)., Conclusions: Our study demonstrates that the absence of TILs predicts SLN metastasis, in multivariate analysis the SLN positivity predicts DFS and OS.

We have earlier shown that microglia, the immune cells of the CNS, release microparticles from cell plasma membrane after ATP stimulation. These vesicles contain and release IL-1beta, a crucial cytokine in CNS inflammatory events. In this study, we show that microparticles are also released by astrocytes and we get insights into the mechanism of their shedding. We show that, on activation of the ATP receptor P2X7, microparticle shedding is associated with rapid activation of acid sphingomyelinase, which moves to plasma membrane outer leaflet. ATP-induced shedding and IL-1beta release are markedly reduced by the inhibition of acid sphingomyelinase, and completely blocked in glial cultures from acid sphingomyelinase knockout mice. We also show that p38 MAPK cascade is relevant for the whole process, as specific kinase inhibitors strongly reduce acid sphingomyelinase activation, microparticle shedding and IL-1beta release. Our results represent the first demonstration that activation of acid sphingomyelinase is necessary and sufficient for microparticle release from glial cells and define key molecular effectors of microparticle formation and IL-1beta release, thus, opening new strategies for the treatment of neuroinflammatory diseases.

We studied 197 patients with thymoma-associated myasthenia gravis (T-MG) to identify variables that can influence the natural history of the disease and the therapeutical approaches. Multivariate analysis showed that neither clinical nor pathological variables were associated with a better chance to reach complete stable remission. The video-assisted thoracoscopic extended thymectomy (VATET) was not significantly correlated with a lower chance of achieving complete stable remission compared with the classical transsternal approach (T-3b) (p=0.1090). Thymoma recurrence was not correlated with surgery by VATET or T-3b. VATET was safe and reliable for removal of thymoma. The low chance of achieving remission (9.64%) in T-MG underlines the importance of an early diagnosis as well as the need for more aggressive therapeutic strategies.

Previous reports showed that receptor-type protein-tyrosine phosphatase PTPRK co-localizes with beta-catenin at adherens junctions, and in vitro experiments suggested that beta-catenin could be substrate of PTPRK-mediated phosphatase activity. beta-catenin is a molecule endowed with a dual function being involved both in cell adhesion and in Wnt signaling pathway. Here we provide evidence for the role of PTPRK in negatively regulating the beta-catenin transcriptional activity by modulating its intracellular and membrane distribution. Expression of PTPRK protein in HEK293 cells and in PTPRK-null melanoma cell lines, one of which harbors a mutated oncogenic beta-catenin, impairs nuclear accumulation of wild type and oncogenic forms of beta-catenin, limits cytosolic levels of tyrosine-phosphorylated beta-catenin, and leads to re-localization of E-cadherin/beta-catenin complexes in ordered membrane phase along cell-cell contacts. This re-modulation of beta-catenin cellular distribution results in the inhibition of cyclin D1 and c-myc protein expression, whose genes are targets of beta-catenin. Tumor cells upon re-expression of PTPRK have a reduced proliferative and migration capacity. Moreover we show that PTPRK is also active in negatively regulating the transactivating function of beta-catenin in normal melanocytes as confirmed by experiments with silenced PTPRK by specific siRNA. Our data show that PTPRK influences transactivating activity of beta-catenin in non-tumoral and neoplastic cells by regulating the balance between signaling and adhesive beta-catenin, thus providing biochemical basis for the hypothesis of PTPRK as a tumor suppressor gene.

Data have been reported on the in vivo adjuvant role of soluble lymphocyte activation gene-3 (LAG-3) recombinant protein in mouse models and on its ability to support the in vitro generation of human, tumor-specific CTLs. In this study, we show that soluble human rLAG-3 protein (hLAG-3Ig) used in vitro as a single maturation agent induces phenotypic maturation of monocyte-derived dendritic cells and promoted the production of chemokines and TNF-alpha inflammatory cytokine. When given in association with optimal or suboptimal doses of CD40/CD40L, hLAG-3Ig functions as a strong costimulatory factor and induces full functional activation of monocyte-derived dendritic cells that includes the production of high level of IL-12p70. Moreover, evidence is here provided that this costimulatory function licensing dendritic cells to produce IL-12p70 is also a functional property of LAG-3 molecules when expressed in a physiological context by CD4(+) activated T cells. Altogether, these data show for the first time a role of LAG-3 in mediating dendritic cell activation when expressed on the T cell surface or released after specific Ag stimulation in the interspaces of immunological synapses.

The individual, unique tumor Ags, which characterize each single tumor, were described 50 years ago in rodents but their molecular characterization was limited to few of them and obtained during the last 20 years. Here we summarize the evidence for the existence and the biological role of such Ags in human tumors, although such evidence was provided only during the last 10 years and by a limited number of studies, a fact leading to a misrepresentation of unique Ags in human tumor immunology. This was also due to the increasing knowledge on the shared, self-human tumor Ags, which have been extensively used as cancer vaccines. In this review, we highlight the biological and clinical importance of unique Ags and suggest how they could be used in clinical studies aimed at assessing their immunogenic and clinical potential both in active and adoptive immunotherapy of human tumors.

Thymic abnormalities are present in approximately 80% of myasthenia gravis (MG) patients, and the thymus seems to be the main site of autosensitization to the acetylcholine receptor. In view of findings that the innate immune system can generate an autoimmune response, we studied the expression of Toll-like receptors (TLRs) 2 to 5, key components of innate immunity signaling pathways, in 37 thymuses from patients with autoimmune MG. TLR4 mRNA levels were significantly greater in thymitis (hyperplasia with diffuse B-cell infiltration) and involuted thymus than in germinal center hyperplasia and thymoma. By immunohistochemistry and confocal microscopy, cells positive for TLR4 protein were rarely detected in thymoma. However, in thymitis TLR4 protein was mostly found on epitheliomorphic (cytokeratin-positive) cells located in close association with clusters of acetylcholine receptor-positive myoid cells in thymic medulla and also at the borders between cortical and medullary areas. B cells were never TLR4-positive. TLR4 protein was also present in remnant tissue of involuted thymus. This is the first finding of a possible link between innate immunity and MG. We speculate that in a subgroup of MG patients, an exogenous or endogenous danger signal may activate the innate immune system and give rise to TLR4-mediated mechanisms contributing to autoimmunity.

The technological advances occurred in the last few years have led to a great increase in the number of tumor associated antigens (TAA) that are currently available for clinical applications. In this review we provide a comprehensive list of human tumor antigens as reported in the literature updated at February 2004. The list includes all T cell-defined epitopes, while excluding analogs or artificially modified epitopes, as well as virus-encoded and antibodies-recognized antigens. TAAs are listed in alphabetical order along with the epitope sequence and the HLA allele which restricts recognition by T cells. Data on the tissue distribution of each antigen are also provided together with an extensive bibliography that allows a rapid search for any additional information may be needed on each single antigen or epitope. Overall, the updated list is a database tool for clinicians, scientists and students who have an interest in the field of tumor immunology and immunotherapy.

The rationale for immunotherapy of human melanoma is based on the knowledge acquired in the molecular characterization of T cell defined antigens which are recognized in vitro by patients' lymphocytes. Based on this information, active immunotherapy (vaccination) and adoptive immunotherapy trials were conducted in metastatic melanoma patients. This review highlights the most important clinical studies and discuss their limits, in terms of both immune and clinical response considering the formulation of the vaccine (cellular, peptide/protein; DNA, etc.) or the features of immune cells used in adoptive immunotherapy. This new knowledge, along with that of escape mechanisms, should allow to improve significantly the clinical response rate in the immunotherapy of melanoma.

In the past 20 years, the approach to biliary lithiasis has changed tremendously as a result of advances in endoscopic and laparoscopic techniques. The two most important open surgical techniques involve extraction of the stones from the common bile duct combined with choledochoenterostomy and papillotomy followed by transduodenal papillosphinteroplasty. Ideally, the choledochotomy is followed by the insertion of a T-tube in the common bile duct. The transcystic approach has never been considered. The first endoscopic papillotomy was performed in 1973. Subsequently, it became the most widely used method for removal of common bile duct stones. In this report we explore the possibility of performing a laparoscopic transduodenal papillosphincteroplasty, following the strict rules commonly used in surgery. After cholecystectomy, a Fogarty catheter, is introduced through the cystic duct. This is followed by a minimal duodenotomy, then incision of the papillar sphincter. In this surgical proposal, we do not intend to substitute technique, but this method should be considered the ultimate solution in the laparoscopic approach to cholecystic choledocholithiasis.

The aims of this study were to assess the efficacy of video-assisted thoracoscopic extended thymectomy (VATET) as a treatment for myasthenia gravis (MG) and to identify prognostic factors for thymectomy success. Clinical efficacy and variables influencing outcome were assessed by life-table and Cox proportional hazards regression analysis. Complete stable remission (CSR), as defined by the MGFA Medical Task Force, was the end point for efficacy. VATET was performed in 159 MG patients and T-3b in 47 MG patients. At 6 years of follow-up, CSR, assessed by life-table analysis, was 50.6% in non-thymomatous VATET patients and 48.7% in non-thymomatous T-3b surgery. By univariate analysis, the presence of thymic hyperplasia (P=0.0002) and treatment only with anticholinesterases (P<0.0001) were positively associated with the probability of CSR. By multivariate analysis, the chance of complete remission was significantly increased by the use of anticholinesterases (odds ratio [OR] 2.45; 95% confidence interval [CI] 1.44-4.17; P=0.001) and the presence of thymic hyperplasia (OR 1.96; 95% CI 1.05-3.68; P=0.036). VATET seems to be effective in inducing CSR in MG with an efficiency similar to that of the T-3b transsternal (TS) approach; it is easy to perform in experienced hands and is associated with low morbidity and negligible esthetic sequelae.

Recent studies increasingly point to a pivotal role of CD4(+) T cells in human anti-tumor immune response. Here we show that lymphocytes purified from a tumor-infiltrated lymph node of a melanoma patient that had remained disease free for 10 years after surgical resection of a lymph node metastasis comprised oligoclonal class II HLA-restricted CD4(+) T cells recognizing the autologous tumor cells in vitro. In fact, the CD4(+) T cell clones isolated from these lymphocytes displayed a tumor-specific, cytotoxic activity in addition to a Th1-like cytokine profile. By a genetic approach, a peptide derived from a mutated receptor-like protein tyrosine phosphatase kappa was identified as a novel HLA-DR10-restricted epitope for all the melanoma-specific CD4(+) T cell clones. The immunogenic peptide was shown to contain the mutated residue that was crucial for T cell recognition and activation. Moreover, a systemic immunity against the mutated peptide was detectable in the patient's peripheral blood T lymphocytes obtained during the disease-free period of follow-up. These findings further support the relevance of CD4(+) T cells directed against mutated epitopes in tumor immunity and provide the rationale for a possible usage of mutated, tumor-specific Ags for immunotherapy of human cancer.

Tumor cells may express antigens which are recognized in a form of HLA/peptide complexes by T cells. The frequency at which different antigens are seen by T cells of melanoma patients and healthy donors was evaluated by human leukocyte antigen (HLA)/peptide tetramer technology which stains T cells bearing the specific receptor for a given epitope. By this technique, it was found that the majority of metastatic melanoma patients can recognize differentiation antigens (particularly Melan-A/MART-1), whereas such a recognition is scanty in the early phase of the disease and in healthy subjects. Despite the presence of melanoma-specific T cells infiltrating tumor lesions, tumor rejection rarely occurs. Among the different mechanisms of such inefficient antitumor response, this review discusses the possible anti-T-cell counterattack mediated by FasL-positive tumor cells, and shows that FasL is located in the cytoplasm of melanoma cells and is transported in the tumor microenvironment through the release of melanosomes. Additionally, mechanisms of suboptimal T cell activation through tumor cell expression of peptide analogs with antagonist activity are described, together with the possibility of overcoming such anergy induction by the usage of optimized tumor epitopes. Down-modulation of HLA expression by target tumor cells and its multiple mechanisms is also considered. Finally, we discuss the role of inducible nitric oxide synthases in determining the inhibition of apoptosis in melanoma cells, which can make such tumor cells resistant to the T-cell attack.

A new enzymatic procedure was developed for isolation of eumelanin from black human hair which might provide a substantially intact pigment for structural characterization. Sequential digestion with protease, proteinase K and papaine in the presence of dithiothreitol afforded a pigment with a 6% w/w protein content. HPLC analysis of pyrrole acids resulting from alkaline H(2)O(2) degradation, carboxyl content determination, and ferricyanide titration showed that the isolated pigment is made up of 5,6-dihydroxyindole (DHI)- and 5, 6-dihydroxyindole-2-carboxylic acid (DHICA)-derived units at a 6:1 ratio, exhibiting a significant degree of oxidative degradation. For comparison, a different eumelanin isolated from black bovine irides by a similar enzymatic procedure was analyzed. Matrix-assisted laser desorption ionization (MALDI) mass spectrometry of the final pigment provided evidence for homologous series of DHICA oligomers, while chemical analysis allowed an estimate of 2:1 DHICA/DHI-derived units in the polymer, with a substantial proportion of intact o-diphenolic functions. Iris melanin proved able to promote the Fenton oxidation of deoxyribose while hair melanin was ineffective. Overall, these results provide, for the first time, unambiguous evidence for marked structural differences of mammalian eumelanins which may be directly related to the diversity of the sites of biosynthesis and storage, as well as to functional role of these pigments.

Increasing evidence supports the view that diffusible melanin-related metabolites do not serve merely as pigment precursors, but may also act as modulators of the responses of the pigmentary cell melanocyte to external stimuli, especially to inflammation. In this study, the effect of melanin precursors 5, 6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) on the Fenton-induced oxidation of deoxyribose was investigated as a model of the oxidative stress processes triggered by the release of iron during inflammation. DHICA caused a powerful inhibition of the H(2)O(2)-Fe(II)/EDTA oxidation under both aerobic and anaerobic conditions, proving to be more efficient than typical hydroxyl radical (HO(*)) scavengers even at low concentrations with respect to deoxyribose. Conversely, DHI in air was a prooxidant at low indole:Fe(II) ratios, but shifted to an antioxidant at higher ratios (>6). The magnitude of the prooxidant effect increased by lowering the pH of the medium or by replacing Fe(II) with Fe(III), but was suppressed by exclusion of oxygen. Both the indoles retained their effects on the Fenton reaction in the absence of EDTA, as a result of their ability to chelate iron ions as evidenced by spectrophotometric experiments. Investigation of the reaction of DHI and DHICA with the Fenton reagent led to the conclusion that the indoles interact efficiently with HO(*), yielding indolesemiquinone species which are then converted to melanin pigments by self-coupling or disproportionation. At low DHI:iron molar ratios, the ability of semiquinones, generated by autoxidation of indoles, to recycle Fe(II) ions prevails, accounting for the observed prooxidant effect. Collectively, the results of this study provide new evidence for melanogenic 5,6-dihydroxyindoles as a novel class of biological antioxidants and point to these compounds as the key to interpreting the response of melanocytes to oxidative injuries. Moreover, the rapid formation of melanin following the exposure of 5, 6-dihydroxyindoles to the Fenton oxidation suggests new mechanisms of skin hyperpigmentation associated with inflammation.

Diffusible melanin-related metabolites have recently been suggested to subserve a variety of functions that are critical for protection of skin against inflammatory stimuli and oxidative tissue injury. We report here the results of in vitro studies showing that 5,6-dihydroxyindole (DHI) and its 2-carboxylic acid (DHICA) exhibit a marked reactivity toward potentially cytotoxic nitrogen oxides produced by autoxidation of nitric oxide (NO) under physiologically relevant conditions. Exposure of DHI or DHICA to NO in air-equilibrated 0.1 M phosphate buffer, pH 7.4, resulted in a fast, concentration-dependent consumption of the substrates and the concomitant deposition of dark melanin-like pigments. All NO-induced oxidations were completely inhibited in the absence of oxygen. Addition of 10 microM DHI and DHICA completely prevented the oxidation of 10 microM alpha-tocopherol in 0.1 M phosphate buffer, pH 7.4 in the presence of 300 microM NO. Overall, these results shed light on novel oxidative pathways of melanin-related metabolites of possible relevance to the mechanisms of skin hyperpigmentation under oxidative stress conditions.

Exposure of alpha-tocopherol (alpha-T) to nitric oxide under aerobic conditions resulted in a complex oxidation process whose final outcome was dictated by the nature of the reaction medium. In a cyclohexane solution, a prevailing route led to a mixture of relatively unstable polar products positive to Griess reagent. On standing at room temperature these were partially converted to the novel 2,3-dimethyl-4-acetyl-4-hydroxy-5-nitroso-2-cyclopentenone derivative. Reaction of alpha-T via a secondary oxidation path led to the formation of alpha-tocopherylquinone (alpha-TQ) as well as of little amounts of the corresponding nitrite ester. A quite different product pattern was observed when the reaction was carried out on a suspension of alpha-T in 0.1 M phosphate buffer, pH 7.4. Besides a significant formation of alpha-TQ and its nitrite ester, product analysis revealed a characteristic pattern of apolar compounds consisting of a yellow dimer and a series of related oligomers. These results provide an improved chemical background to inquire into the role of alpha-T in nitric oxide-induced tissue injury.

Thymectomy is often an extremely useful therapeutic procedure in myasthenia gravis (MG) and is usually indicated for adult patients with generalized disease. Because remnants of thymus may remain in extrathymic fat, an extended thymectomy is recommended. A new surgical approach without sternotomy: video-assisted thoracoscopic extended thymectomy (VATET) was performed in 30 MG patients. The weight of removed thymus ranged from 10.8 to 113 grams. The weight of fatty tissue removed from pretracheal, anterior mediastinal and costophrenic areas ranged from 6.3 to 74.8 grams. Histological examination revealed thymic remnants in 14.8% of pretracheal fat samples and in 33.3% of samples from anterior mediastinal plus costophrenic areas. These findings indicate that VATET is a radical procedure and may be the first choice surgery for young female MG patients, since aesthetic sequelae are reduced compared to procedures involving sternotomy.