mRNAs translation and tumorigenesis

Translational control has a direct impact on cancer development and progression. Quantitative and qualitative changes of cap-dependent translation initiation contribute to neoplastic transformation and progression. However, the idea that “alternative” mechanisms of translation initiation, such as IRES-dependent translation, can be involved in the tumorigenesis is emerging. Because the relevance of this kind of translation initiation in cancer progression is not so well clarified, the purpose of my work was to study the impact of IRES-dependent mRNA translation on tumourigenesis and cancer progression with particular regard for breast cancer. The data obtained clarify the function of cap-independent translation in cancer. Particularly they suggested that the deregulation of IRES-dependent translation can be considered a sort of pro-oncogenic stimulus characterized by the inhibition of the expression of some proteins that block cell growth and proliferation and by the over expression of other proteins that contributed to cell survival. In addition, under stress condition, such as a hypoxia, in immortalized epithelial cell lines, changes in cap-independent translation are associated with an induction of expression of stem cell markers, and with the selection of a sub group of cells that have an increased ability to self-renewing and therefore in the acquisition of a more aggressive phenotype.

Marcatori molecolari circolanti: quale ruolo nei pazienti con tumori solidi?

Background: Circulating tumor cells (CTCs) and circulating free plasma DNA (FPDNA) have been proposed as biomarkers predictive of outcome and response to therapy in solid tumors. We investigated the multiple associations of the presence of CTC and the levels of FPDNA with the outcome and/or the response to chemotherapy in patients with localized breast cancer (LBC), metastatic breast cancer (MBC) and advanced ovarian cancer (AOC). Experimental Design: Blood samples were collected before (baseline), during and after therapy in 40 LBC and 50 AOC patients treated with neo-adjuvant chemotherapy. In 20 MBC patients blood was sampled at baseline and every each cycle of adjuvant chemotherapy. Real time PCR was applied to quantify FPDNA using the Quantifiler Human Quantification kit and CTCs through the detection of tumor-cell specific mRNA levels with or without epithelial enrichment. Results: At baseline CTCs were detected in 90% MBC, 42.5% LBC and 33% AOC patients respectively. The presence of baseline CTC was significantly associated with shorter overall survival (OS) in MBC and AOC patients, and shorter progression free survival (PFS) in LBC patients. Presence of CTCs at the end of neo-adjuvant chemotherapy was detected in 42% LBC and 18% AOC patients and was associated with shorter PFS and OS only in LBC. Increased FPDNA levels at baseline were found in 65% MBC, 17.5% LBC and 76% AOC patients but never related to OS. Baseline FPDNA high levels were associated with shorter PFS only in LBC patients. High FPDNA levels after neo-adjuvant chemotherapy were detected in 57% LBC and 48% AOC patients. Increased FPDNA after neo-adjuvant was associated with response to therapy and shorter PFS in AOC patients. Conclusions: Detection of CTCs may represent a prognostic and predictive biomarker in LBC, MBC and AOC. Quantification of FPDNA could be useful for monitoring response to therapy in AOC patients.

Ribosome Biogenesis and cell cycle regulation: Effect of RNA Polymerase III inhibition

In cycling cells positive stimuli like nutrient, growth factors and mitogens increase ribosome biogenesis rate and protein synthesis to ensure both growth and proliferation. In contrast, under stress situation, proliferating cells negatively modulate ribosome production to reduce protein synthesis and block cell cycle progression. The main strategy used by cycling cell to coordinate cell proliferation and ribosome biogenesis is to share regulatory elements, which participate directly in ribosome production and in cell cycle regulation. In fact, there is evidence that stimulation or inhibition of cell proliferation exerts direct effect on activity of the RNA polymerases controlling the ribosome biogenesis, while several alterations in normal ribosome biogenesis cause changes of the expression and the activity of the tumor suppressor p53, the main effector of cell cycle progression inhibition. The available data on the cross-talk between ribosome biogenesis and cell proliferation have been until now obtained in experimental model in which changes in ribosome biogenesis were obtained either by reducing the activity of the RNA polymerase I or by down-regulating the expression of the ribosomal proteins. The molecular pathways involved in the relationship between the effect of the inhibition of RNA polymerase III (Pol III) activity and cell cycle progression have been not yet investigated. In eukaryotes, RNA Polymerase III is responsible for transcription of factors involved both in ribosome assembly (5S rRNA) and rRNA processing (RNAse P and MRP).Thus, the aim of this study is characterize the effects of the down-regulation of RNA Polymerase III activity, or the specific depletion of 5S rRNA. The results that will be obtained might lead to a deeper understanding of the molecular pathway that controls the coordination between ribosome biogenesis and cell cycle, and might give useful information about the possibility to target RNA Polymerase III for cancer treatment.

The vulnerable carotid plaque. Identification of endothelial markers predictive of plaque weakness, rupture predisposition and neoangiogenesis

Background. Neoangiogenesis is crucial in plaque progression and instability. Previous data from our group demonstrated that intra-plaque neovessels show both a Nestin+/WT+ and a Nestin+/WT1- phenotype, the latter being correlated with complications and plaque instability. Aims. The aims of the present thesis are: (i) to confirm our previous results on Nestin/WT1 phenotype in a larger series of carotid atheromatous plaques, (ii) to evaluate the relationship between the Nestin+/WT1- neoangiogenesis phenotype and plaque morphology, (iii) to evaluate the relationship between the immunohistochemical and histopathological characteristics and the clinical instability of the plaques. Materials and Methods. Seventy-three patients (53 males, 20 females, mean age 71 years) were consecutively enrolled. Symptoms, brain CT scan, 14 histological variables, including intraplaque hemorrhage and diffuse calcifications, were collected. Immunohistochemistry for CD34, Nestin and WT1 was performed. RT-PCR was performed to evaluate Nestin and WT1 mRNA (including 5 healthy arteries as controls). Results. Diffusely calcified plaques (13 out of 73) were found predominantly in females (P=0.017), with a significantly lower incidence of symptoms (TIA/stroke) and brain focal lesions (P=0.019 and P=0.013 respectively) than not-calcified plaques, but with the same incidence of intraplaque complications (P=0.156). Accordingly, both calcified and not calcified plaques showed similar mean densities of positivity for CD34, Nestin and WT1. The density of Nestin and WT1 correlated with the occurrence of intra-plaque hemorrhage in all cases, while the density of CD34 correlated only in not-calcified plaques. Conclusions. We confirmed that the Nestin+/WT1- phenotype characterizes the neovessels of instable plaques, regardless the real amount of CD34-positive neoangiogenesis. The calcified plaques show the same incidence of histological complications, albeit they do not influence symptomatology and plaque vulnerability. Female patients show a much higher incidence of not-complicated or calcified plaques, receiving de facto a sort of protection compared to male patients.

Drugs down-regulating E2F-1 expression hinders cell proliferation through a p53-indipendent mechanism

E2F-1 is a transcription factor that plays a key role in cell-cycle control at G1/S check-point level by regulating the timely expression of many target genes whose products are required for S phase entry and progression. In mammalian cells, E2F-1 is negatively regulated by hypo-phosphorylated Retinoblastoma protein (pRb) whereas it is protected against degradation by its binding to Mouse Double Minute 2 protein (MDM2). In this study we experimented a drug combination in order to obtain a strong down-regulation of E2F-1 by acting on two different mechanisms of E2F-1 regulation mentioned above. This was achieved by combining drugs inhibiting the phosphorylation of pRb with drugs inactivating the MDM2 binding capability. The mechanism of action of these drugs in down-regulating E2F-1 level and activity is p53 independent. As expected, when combined, these drugs strongly inhibits E2F-1 and hinder cell proliferation in p53-/- and p53-mutated cells by blocking them in G1 phase of cell cycle, suggesting that E2F-1 down-regulation may represent a valid chemotherapeutic approach to inhibit proliferation in tumors independently of p53 status.

The constitutive activation of the DNA damage response pathway is a novel therapeutic target in aggressive B-cell lymphoma

The recent finding that MYC-driven cancers are sensitive to inhibition of the DNA damage response (DDR) pathway, prompted us to investigate the role of DDR pathway as therapeutic target in diffuse large B-cell lymphoma (DLBCL), which frequently overexpresses the MYC oncogene. In a preliminary immunohistochemical study conducted on 99 consecutive DLBCL patients, we found that about half of DLBCLs showed constitutive expression of the phosphorylated forms of checkpoint kinases (CHK) and CDC25c, markers of DDR activation, and of phosphorylated histone H2AX (γH2AX), marker of DNA damage and genomic instability. Constitutive γH2AX expression correlated with c-MYC levels and DDR activation, and defined a subset of tumors characterised by poor outcome. Next, we used the CHK inhibitor PF-0477736 as a tool to investigate whether the inhibition of the DDR pathway might represent a novel therapeutic approach in DLBCL. Submicromolar concentrations of PF-0477736 hindered proliferation in DLBCL cell lines with activated DDR pathway. These results were fully recapitulated with a different CHK inhibitor (AZD-7762). Inhibition of checkpoint kinases induced rapid DNA damage accumulation and apoptosis in DLBCL cell lines and primary cells. These data suggest that pharmacologic inhibition of DDR through targeting of CHK kinases may represent a novel therapeutic strategy in DLBCL. The second part of this work is the clinical, molecular and functional description of a paradigmatic case of primary refractory Burkitt lymphoma characterized by spatial intratumor heterogeneity for the TP53 mutational status, high expression levels of genomic instability and DDR activation markers, primary resistance to chemotherapy and exquisite sensitivity to DDR inhibitors.

Contribution of vascular resident mesenchymal stromal cells to abdominal aortic aneurysm pathogenesis: increased MMP-9 expression and ineffective immunomodulation

Background. Ageing and inflammation are critical for the occurrence of aortic diseases. Extensive inflammatory infiltrate and excessive ECM proteloysis, mediated by MMPs, are typical features of abdominal aortic aneurysm (AAA). Mesenchymal Stromal Cells (MSCs) have been detected within the vascular wall and represent attractive candidates for regenerative medicine, in virtue of mesodermal lineage differentiation and immunomodulatory activity. Meanwhile, many works have underlined an impaired MSC behaviour under pathological conditions. This study was aimed to define a potential role of vascular MSCs to AAA development. Methods. Aortic tissues were collected from AAA patients and healthy donors. Our analysis was organized on three levels: 1) histology of AAA wall; 2) detection of MSCs and evaluation of MMP-9 expression on AAA tissue; 3) MSC isolation from AAA wall and characterization for mesenchymal/stemness markers, MMP-2, MMP-9, TIMP-1, TIMP-2 and EMMPRIN. AAA-MSCs were tested for immunomodulation, when cultured together with activated peripheral blood mononuclear cells (PBMCs). In addition, a co-colture of both healthy and AAA MSCs was assessed and afterwards MMP-2/9 mRNA levels were analyzed. Results. AAA-MSCs showed basic mesenchymal properties: fibroblastic shape, MSC antigens, stemness genes. MMP-9 mRNA, protein and enzymatic activity were significantly increased in AAA-MSCs. Moreover, AAA-MSCs displayed a weak immunosuppressive activity, as shown by PBMC ongoing along cell cycle. MMP-9 was shown to be modulated at the transcriptional level through the direct contact as well as the paracrine action of healthy MSCs. Discussion. Vascular injury did not affect the MSC basic phenotype, but altered their function, a increased MMP-9 expression and ineffective immunmodulation. These data suggest that vascular MSCs can contribute to aortic disease. In this view, the study of key processes to restore MSC immunomodulation could be relevant to find a pharmacological approach for monitoring the aneurysm progression.

Determinación de la frecuencia de infección en el sitio operatorio en pacientes intervenidos quirúrgicamente de cirugía abdominal de emergencia en el Hospital Vicente Corral Moscoso julio-enero 2006-2007

Se realizó un estudio transversal; en un universo de 180 pacientes. Los datos se obtuvieron por entrevista y se analizaron con el software Epi-Info. Resultados La prevalencia de de infección del sitio de la herida quirúrgica fue del 10.6. La asociación con el sobrepeso proporcionó una p= 0.93, razón de prevalencia (PR) 0.96, (IC 950.4-2.3); con la evolución del cuadro clínico mayor a 12 horas p=0.11, PR 2.9 (IC 950.7-12.1); con patología clínica coexistente p=0.006, PR 3.1 (IC 951.3-7.3); con más de 60minutos de exposición al acto quirúrgico se infectaron el 12.3de pacientes. En los hombres la prevalencia fue del 10.3(IC 953.9-16.7), en las mujeres del 10.8(IC 954.5-17.1); en los pacientes mayores a 64 años fue del 5.3(IC 950-15) y en los menores a 64 del 11.2(IC 956.3-16.1). Conclusión: la prevalencia de infección del sitio de la herida quirúrgica fue del 10.6. Se encontró asociación significativa con la patología clínica asociada, con la herida contaminada y sucia y con el acto quirúrgico mayor a 60 minutos de exposición

Correlacion clinica-patologica de corioamnionitis en pacientes que ingresan al servicio ginecologia en el año 2009 en el Hospital Universitario Clinica San Rafael

Este trabajo tuvo como utilidad básica determinar cuál es la correlación del diagnóstico clínico con los criterios de Gibss y con el Gold estándar que es la patología en las paciente con corioamnionitis para así poder establecer si el diagnostico se realizó en forma adecuada y cuáles son los criterios más relevantes para su diagnóstico. Dicha investigación se realizó de la siguiente manera: 1. Se Identificaron las pacientes que ingresaron al servicio de urgencias o al servicio de ginecología de la Clínica san Rafael con diagnóstico de Corioamnionitis (teniendo en cuenta los criterios de Gibbs), pacientes que desarrollaron la entidad durante el trabajo de parto o a las cuales se les hizo el diagnostico durante el mismo parto se establecieron los criterios de Gibss para cada una como parte del diagnóstico clínico de corioamnionitis 2. se revisaron los estudios anatomo-patologico realizado a las placentas culminado el proceso de trabajo de parto ya fuera por vía vaginal o cesárea y se realizó un estudio de asociación entre el resultado patológico de corioamnionitis y el diagnóstico clínico. Con esta investigación se estableció el diagnóstico clínico se correlaciono con la patología en el 54% de los casos 1. la asociación de los criterios de Gibbs con el diagnostico patológico, encontrando que individualmente los criterios que se asocian con el diagnóstico definitivo de corioamnionitis fueron: la taquicardia materna OR (8,53), taquicardia fetal OR (7,7), y leucocitosis OR (2,86), la descarga vaginal fétida y la hipersensibilidad uterina tuvieron menor significancia con OR de 1,24 y 1,1 respectivamente. e En la regresión logística se encontró que los criterios de Gibbs fueron estadísticamente significativos en donde para la taquicardia materna OR (7,29), taquicardia fetal OR (4,107), hipersensibilidad uterina OR (2,96), leucocitosis OR (4,93) y descarga vaginal OR (2,65)

Clinica chirurgica.

Vols. 45-46 never published.

Patologia e parâmetros oculares em doentes com infeção pelo VIH - Avaliação antes e após Terapêutica Antirretrovirica combinada

INTRODUÇÃO: As complicações oculares do VIH/SIDA são comuns e podem afetar qualquer tecido do olho. Na era da terapêutica antirretroviral combinada (TARc), houve uma redução drástica nas infeções oportunistas oculares. O impacto da terapêutica em outras alterações na visão de doentes VIH+ sem retinopatia infecciosa, como alterações na sensibilidade ao contraste (SC), visão cromática (VC) e nos campos visuais, sinal de uma disfunção microvascular retiniana, não está totalmente esclarecido. OBJETIVOS: Determinar os efeitos da TARc em parâmetros e patologia oculares de doentes VIH+ que vão iniciar ou reiniciar TARc MÉTODOS: Foi realizado um estudo observacional, longitudinal, transversal e prospetivo com a inclusão de 31 doentes VIH+ sem infeções oculares oportunistas, que iam iniciar ou reiniciar TARc. Após serem recolhidos alguns dados da história clínica, foi feita uma avaliação oftalmológica completa que incluiu: biomicroscopia do segmento anterior, acuidade visual com a escala de ETDRS, pressão intra-ocular com a tonometria de aplanação de Goldmann, SC com o CSV-1000E, VC com o Farnsworth- Munsell 100 e perimetria com o programa 24-2 do Octopus® 900. Após midríase farmacológica foram realizadas fotografias do segmento posterior, avaliação da espessura da camada de fibras nervosas (CFN) e macular com o OCT Stratus™ e avaliação da densidade do cristalino e do ângulo irido-corneano pelo Pentacam®. Cerca de 9 meses após o início da TARc, foi realizada uma segunda observação oftalmológica usando os mesmos métodos. Procuraram-se associações estatísticas entre vários parâmetros da infeção pelo VIH e a avaliação oftalmológica. RESULTADOS: Na primeira observação, encontraram-se 15 olhos (24%) com complicações anteriores do VIH, 10 olhos (16%) com retinopatia do VIH, 15 (24%) com alterações vasculares retinianas e 6 (10%) com defeitos na CFN; nenhuma destas alterações estava relacionada com o nível de linfócitos CD4+ ou carga viral. A SC, VC e perimetria estavam alteradas em 45%, 68% e 76% dos olhos, respetivamente. Encontrou-se uma correlação positiva entre valores mais elevados de linfócitos T CD4+ e melhor SC, sobretudo nos 6 e 12 ciclos por grau e no valor soma da SC (p<0,01). A avaliação pelo OCT revelou que os doentes com CFN fina tinham tendencialmente infeção mais antiga, níveis mais baixos de linfócitos CD4+ (p<0,05) e pior SC (p<0,05). Foi possível realizar segunda observação em 16 doentes (52%). Após 9 meses de TARc as alterações encontradas na primeira avaliação mantiveram-se, com exceção da retinopatia do VIH que regrediu. As alterações na SC, VC, perimetria e na espessura da CFN mantiveram-se; a densidade do cristalino não se alterou com a reconstituição imunitária após TARc. CONCLUSÕES: Foram detetadas alterações na avaliação oftalmológica de doentes VIH+ sem retinopatia infecciosa e que parecem estar relacionadas com a existência de microvasculopatia e disfunção neurorretiniana associada. A reconstituição imunitária com a TARc não parece levar a uma melhoria desta disfunção apesar da recuperação da imunidade para valores normais.

Tuberculose em necropsias realizadas no Serviço de Anatomia Patológica da Faculdade de Medicina de Botucatu

Entre 6.316 necropsias realizadas, no período de 1969 a 2000, no Departamento de Patologia da Faculdade de Medicina de Botucatu da Universidade Estadual Paulista (FMB/UNESP), foram encontradas 240 necropsias com diagnóstico de tuberculose, sendo 117 registradas como doença principal (grupo tuberculose/doença principal) e 123, como doença associada (grupo tuberculose/doença associada). No grupo tuberculose/doença principal, 100% apresentavam tuberculose ativa, com 80 ocorrências em homens e 37 em mulheres e média de idade de 47,7 anos. Caquexia (37,2%) e cor pulmonale (23,7%) foram as co-morbidades mais prevalentes nesse grupo. Os pulmões estavam comprometidos em 95,7% dos casos, seguido pelos linfonodos (38,9%) e pleuras (27,1%). Os padrões morfológicos das lesões pulmonares foram: 1. miliar, 58,4%; 2. cavernas, 56,6%; 3. fibrose, 41,5%; 4. bronquiectasias, 26,5%; 5. enfisema, 19,4%; e 6. cistos, 1,7%. Cavernas foram observadas em diferentes áreas, com discreto predomínio no pulmão direito, sendo a localização apical preferencial (100%) e quase sempre bilaterais (94%). Lesões miliares, bronquiectasias e fibrose estavam distribuídas, de forma difusa e aleatória, nos pulmões. No grupo tuberculose/doença associada também houve predomínio de homens (70,8%). Nesses casos, a AIDS e o alcoolismo crônico foram as doenças principais mais freqüentes, representando 22% e 16,3%, respectivamente. Os pulmões estavam acometidos em 85,2% dessas necropsias (100% nos casos de AIDS), seguidos pelos linfonodos (31,9%) e baço (28,6%). Nossos dados corroboram a importância da necropsia no estudo e no conhecimento da tuberculose, fornecendo subsídios para uma melhor abordagem clínica e epidemiológica dessa doença em nossa região.

Valutazione clinica e radiologica di manifestazioni a livello di distretto cefalico in pazienti affetti da neurofibromatosi

Con il termine neurofibromatosi (NF) si comprendono almeno sette malattie genetiche diverse ma accomunate dalla presenza di neurofibromi localizzati nei distretti cutaneo, orale, viscerale e scheletrico. Dal momento che la NF1 (malattia di Von Recklinghausen), una delle più diffuse malattie genetiche, può avere manifestazioni a livello orale, gli odontoiatri devono essere a conoscenza delle sue caratteristiche patognomoniche. Obiettivo della tesi è la ricerca di manifestazioni della NF1 a livello dell’apparato stomatognatico. Materiali e metodi 98 pazienti affetti da NF1 (44 maschi, 54 femmine dai 2 ai 24 anni; età media di 8,6 anni) sono stati indagati clinicamente e radiograficamente; clinicamente si sono valutati: prevalenza della patologia cariosa (dmft; DMFt), indice parodontale di comunità (CPI), anomalie dentali, presenza di lesioni a livello dei tessuti molli intraorali, presenza di patologie ortopedico-ortodontiche; presenza di abitudini viziate; sulle ortopantomografie eseguite su 49 pazienti (23 maschi, 26 femmine dai 6 ai 19 anni; età media di 10 anni) si sono valutate manifestazioni ossee e dentali caratteristiche della sindrome. Risultati Dallo studio è emerso che i pazienti affetti da NF1 presentano: dmft/DMFt e CPI elevati (dmft = 2,1; DMFt = 1,6; tessuti gengivali con sanguinamento nel 50% dei casi; eruzione dentale anticipata nel 10%; eruzione dentale ritardata nel 10%; taurodontismo nel 16%; patologie ortopedico-ortodontiche nel 40% (tendenza alla terza classe scheletrica, palato ogivale, morso aperto anteriore, morso coperto, morso crociato posteriore monolaterale, morso crociato posteriore bilaterale, linea mediana deviata, incompetenza labiale); abitudini viziate nel 27% (respirazione orali e deglutizione infantile); lesione neurofibromatosa della gengiva in un caso; per quanto riguarda la valutazione delle ortopantomografie, manifestazioni ossee caratteristiche della sindrome sono state evidenziate nel 28% dei casi (incisura coronoide deformata, processo coronoide ipoplasico o pseudoallungato, condilo ipoplasico, condilo iperplasico, canale mandibolare allargato, forame mandibolare allargato e alto, bordo inferiore della mandibola deformato). La necessità di programmi ed interventi di screening e follow-up periodici (visite odontoiatriche a partire dal momento della diagnosi a cadenza semestrale, esami radiografici a partire dai 6 anni di età a cadenza stabilita individualmente in funzione del livello di rischio) è supportata dall’elevato rischio di patologie cariosa e parodontale e dalla presenza di manifestazioni a livello dei tessuti duri e molli del distretto cefalico a documentato rischio di trasformazione maligna. Parole chiave: neurofibromatosi, patologie orali, distretto cefalico.

Il coniglio come modello sperimentale per lo studio degli effetti neurologici indotti da Cobalto

Sono stati studiati gli effetti tossici dell’esposizione cronica a cobalto e cromo. In passato, questa tossicità, che colpiva lavoratori esposti per ragioni occupazionali, è stata un problema molto sentito. Tuttavia, recenti pubblicazioni hanno descritto una specifica tossicità mediata da elevati livelli di cobalto e cromo, anche in pazienti portatori di protesi metalliche, quali gli impianti d’anca. Anche se sintomi clinici tra cui, cecità, sordità e neuropatia periferica, suggeriscono uno specifico neurotropismo, ancora poco è conosciuto delle basi neuropatologiche di questo processo ed oltretutto non ne è ancora stata apportata un’evidenza sperimentale. In questo progetto di ricerca, quindi, si è voluto approfondire il meccanismo patogenetico da cui scaturiscono tali sintomi neurologici, utilizzando come modello sperimentale il coniglio. Conigli New Zealand White sono stati trattati con dosi endovenose ripetute di cobalto e cromo, inoculati singolarmente od in associazione tra loro. Nessuna evidente alterazione clinica o patologica è stata associata alla somministrazione di solo cromo, nonostante gli elevati livelli in sangue e tessuti, mentre i trattati con cobalto-cromo o solo cobalto hanno mostrato segni clinici gravanti sul sistema vestibolo-cocleare; il cobalto, quindi, è stato identificato come il maggiore elemento scatenante neurotossicità. Inoltre all’esame istopatologico gli animali hanno mostrato severa deplezione delle cellule gangliari retiniche e cocleari, assieme a danno al nervo ottico e perdita di cellule sensitive capellute dell’orecchio. È risultato infine evidente che la gravità delle alterazioni è stata correlata al dosaggio ed al tempo di esposizione; dati questi che confermano, quindi, le precedenti osservazioni fatte su pazienti umani esposti a rilascio abnorme di cobalto e cromo da usura di protesi d’anca. È stato ipotizzato che il cobalto agisca sui mitocondri provocando l’incremento di produzione di specie reattive dell’ossigeno e il rilascio di fattori proapoptotici, causando sulle cellule neuronali un danno proporzionale al loro fabbisogno energetico e grado di mielinizzazione.