Browsing by Author "Ribeiro, P"
Now showing 1 - 10 of 10
Results Per Page
Sort Options
- Adult B-Cell Acute Lymphoblastic Leukemia Cells Display Decreased PTEN Activity and Constitutive Hyperactivation of PI3K/Akt Pathway Despite High PTEN Protein LevelsPublication . Gomes, AM; Soares, M; Ribeiro, P; Caldas, J; Póvoa, V; Martins, L; Melão, A; Serra-Caetano, A; Botelho de Sousa, A; Lacerda, J; Barata, JAdult B-cell acute lymphoblastic leukemia remains a major therapeutic challenge, requiring a better characterization of the molecular determinants underlying disease progression and resistance to treatment. Here, using a phospho-flow cytometry approach we show that adult diagnostic B-cell acute lymphoblastic leukemia specimens display PI3K/Akt pathway hyperactivation, irrespective of their BCR-ABL status and despite paradoxically high basal expression of PTEN, the major negative regulator of the pathway. Protein kinase CK2 is known to phosphorylate PTEN thereby driving PTEN protein stabilization and concomitant PTEN functional inactivation. In agreement, we found that adult B-cell acute lymphoblastic leukemia samples show significantly higher CK2 kinase activity and lower PTEN lipid phosphatase activity than healthy controls. Moreover, the clinical-grade CK2 inhibitor CX-4945 (Silmitasertib) reversed PTEN levels in leukemia cells to those observed in healthy controls, and promoted leukemia cell death without significantly affecting normal bone marrow cells. Our studies indicate that CK2-mediated PTEN posttranslational inactivation, associated with PI3K/Akt pathway hyperactivation, are a common event in adult B-cell acute lymphoblastic leukemia and suggest that CK2 inhibition may constitute a valid, novel therapeutic tool in this malignancy.
- Asialotransferrina Discriminante do Consumo Excessivo Activo de Álcool, Sub-Agudo e Crónico. Utilidade Clínica na Doença HepáticaPublication . Peneda, J; Fonseca, A; Martins Neves; Ribeiro, P; Alves, M; Redondo, I; Calinas, F; Martins, MCA determinação dos níveis séricos de transferrina deficiente em carbo-hidratos (CDT) e do rácio de transferrina no consumidor abusivo persistente de álcool aparece com promissora utilidade na área da alcoologia. Na série actual demonstra-se excelente especificidade (970 o) no entanto com fraca sensibilidade (52° o) para o CDT. Contudo o rácio CDT Tft adiciona-lhe uma sensibilidade acrescida atingindo 740 o mantendo a elevada especificidade. Nos consumidores abusivos 70g dia) persistentes, este índice que se correlaciona positivamente com a transferrina sérica, é capaz de escurtinar em elevada frequência estas capitações de álcool e mostra uma informação independente pois não se correlaciona significativamente com os níveis dos marcadores biológicos tradicionais (AST, ALT, GGT, VGM). Embora com limitações metodológicas definidas, estes índices prenunciam, com melhoria da acessibilidade técnica, uma aplicabilidade prática no rastreio de consumidores abusivos crónicos. Na área da hepatologia o comportamento do CDT e ácio da transferrina é capaz de afirmar em elevada frequência o envolvimento do etanol no estudo da natureza de uma doença hepática crónica. No entanto, o grau de lesão do figado tomado pelo índice hepático PGA, não influencia apreciavelmente os níveis séricos do CDT e rácio de transferrina. Na presente série, as circunstancias e condições do consumo de álcool parecem ser o determinante independente do carácter informativo que estes índices revelam.
- Candidemia in Acute Leukemia PatientsPublication . Ribeiro, P; Botelho de Sousa, A; Aveiro, F; Nunes, O; Fernandes, JP; Gouveia, JFungal infections are an important cause of morbidity and mortality in patients with acute leukemia (AL). Candidemia, once rare, is now a common nosocomial infection because of the intensity of chemotherapy, prolonged neutropenia, administration of broad-spectrum antibiotics and use of central venous catheters (CVC). We retrospectively identified patients treated for AL from 6/86 to 6/95 who also had candidemia. We describe 28 patients (incidence 6.3%) with a median age of 39 years, 24 of whom were on remission induction and 4 on postremission chemotherapy. All patients had CVC and empiric antimicrobial therapy, 4 had been given prophylactic antifungal drugs, and 2 had parenteral nutrition. Neutropenia was profound (median leukocyte nadir 200/microliters, median duration 19 days). Candida was isolated in blood cultures 10 days (median) after the start of neutropenia. The clinical presentation included fever (100%), respiratory symptoms (71.4%), skin lesions (39.2%) and septic shock (17.8%). Amphotericin B was given to 17 patients and liposomal amphotericin to 5 patients. Infection resolved in 18 patients (64.2%). 10 of whom were in complete remission. Mortality from candidemia was 17.8% (5/28). In conclusion, fungal infections are responsible for death in a significant number of patients. In our series treatment success was related to its rapid onset and to the recovery of neutropenia.
- Colorimetric Assessment of BCR-ABL1 Transcripts in Clinical Samples Via Gold NanoprobesPublication . Vinhas, R; Correia, C; Ribeiro, P; Lourenço, A; Botelho de Sousa, A; Fernandes, A; Baptista, PGold nanoparticles functionalized with thiolated oligonucleotides (Au-nanoprobes) have been used in a range of applications for the detection of bioanalytes of interest, from ions to proteins and DNA targets. These detection strategies are based on the unique optical properties of gold nanoparticles, in particular, the intense color that is subject to modulation by modification of the medium dieletric. Au-nanoprobes have been applied for the detection and characterization of specific DNA sequences of interest, namely pathogens and disease biomarkers. Nevertheless, despite its relevance, only a few reports exist on the detection of RNA targets. Among these strategies, the colorimetric detection of DNA has been proven to work for several different targets in controlled samples but demonstration in real clinical bioanalysis has been elusive. Here, we used a colorimetric method based on Au-nanoprobes for the direct detection of the e14a2 BCR-ABL fusion transcript in myeloid leukemia patient samples without the need for retro-transcription. Au-nanoprobes directly assessed total RNA from 38 clinical samples, and results were validated against reverse transcription-nested polymerase chain reaction (RT-nested PCR) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The colorimetric Au-nanoprobe assay is a simple yet reliable strategy to scrutinize myeloid leukemia patients at diagnosis and evaluate progression, with obvious advantages in terms of time and cost, particularly in low- to medium-income countries where molecular screening is not routinely feasible. Graphical abstract Gold nanoprobe for colorimetric detection of BCR-ABL1 fusion transcripts originating from the Philadelphia chromosome.
- A Double Philadelphia Chromosome-Positive Chronic Myeloid Leukemia Patient, Co-Expressing P210 BCR-ABL1 and P195 BCR-ABL1 IsoformsPublication . Vinhas, R; Lourenço, A; Santos, S; Ribeiro, P; Silva, M; Botelho de Sousa, A; Baptista, P; Fernandes, A
- New Prospects for the Management of Cardiovascular Effects of Tyrosine Kinase Inhibitors in Patients with Chronic Myeloid LeukemiaPublication . Almeida, A; Almeida, A; Melo, T; Guerra, L; Lopes, L; Ribeiro, P; Duarte, M; Mota, A; Fontes-Carvalho, RThe use of tyrosine kinase inhibitors (TKIs) for the treatment of chronic myeloid leukemia has significantly altered the prognosis of this disease, enabling close to normal life expectancy. Despite their undeniable benefits, the use of TKIs is associated with an increased risk of side effects on the cardiovascular system, particularly of atherothrombotic events. It is therefore necessary to understand and prevent the adverse effects of these drugs, in order to enable antileukemic therapy to continue and to minimize patients' toxic exposure. This multidisciplinary consensus document, developed through a collaboration between hematologists and cardiologists, aims to review the cardiovascular toxicity associated with various TKIs and to establish recommendations for the follow-up of these patients. Measures are also proposed for the assessment and reduction of cardiovascular risk in these patients and referral criteria, and relevant drug interactions are discussed.
- A Novel BCR-ABL1 Mutation in a Patient with Philadelphia Chromosome-Positive B-Cell Acute Lymphoblastic LeukemiaPublication . Vinhas, R; Lourenço, A; Santos, S; Lemos, M; Ribeiro, P; Botelho de Sousa, A; Viana Baptista, P; Ramos Fernandes, APhiladelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) represents the most common genetic subtype of adult ALL (20%-30%) and accounts for approximately 50% of all cases in the elderly. It has been considered the subgroup of ALL with the worst outcome. The introduction of tyrosine kinase inhibitors (TKIs) allows complete hematologic remission virtually in all patients, with improved disease-free survival and overall survival. Nevertheless, the emergence of resistant mutations in BCR-ABL1 may require different TKI strategies to overcome the patient's resistance and disease relapse. Here, we report a Ph+B-ALL case with persistent minimal residual disease (MRD) after treatment with dasatinib. The patient expressed the P190BCR-ABL1 isoform and a novel BCR-ABL1 mutation, p.Y440C. The latter is in the C-terminal lobe of the kinase domain, which likely induces deviations in the protein structure and activity and destabilizes its inactive conformation. The treatment was substituted by bosutinib, which binds to the active conformation of the protein, prior to allogeneic bone marrow transplant to overcome the lack of a complete response to dasatinib. These findings strengthen the importance of BCR-ABL1 mutational screening in Ph+ patients, particularly for those who do not achieve complete molecular remission.
- A Pilot Study on the Metabolic Impact of Mediterranean Diet in Type 2 Diabetes: Is Gut Microbiota the Key?Publication . Ismael, S; Silvestre, MP; Vasques, M; Araújo, JR; Morais, J; Duarte, MI; Pestana, D; Faria, A; Pereira-Leal, JB; Vaz, J; Ribeiro, P; Teixeira, D; Marques, C; Calhau, CThe Mediterranean diet (MD) has been recommended for type 2 diabetes (T2D) treatment. The impact of diet in shaping the gut microbiota is well known, particularly for MD. However, the link between MD and diabetes outcome improvement is not completely clear. This study aims to evaluate the role of microbiota modulation by a nonpharmacological intervention in patients with T2D. In this 12-week single-arm pilot study, nine participants received individual nutritional counseling sessions promoting MD. Gut microbiota, biochemical parameters, body composition, and blood pressure were assessed at baseline, 4 weeks, and 12 weeks after the intervention. Adherence to MD [assessed by Mediterranean Diet Adherence Screener (MEDAS) score] increased after the intervention. Bacterial richness increased after 4 weeks of intervention and was negatively correlated with fasting glucose levels and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). Prevotella to Bacteroides ratio also increased after 4 weeks. In contrast, glycated haemoglobin (HbA1c) and HOMA-IR were only decreased at the end of study. Alkaline phosphatase activity was assessed in fecal samples and was negatively correlated with HbA1c and positively correlated with bacterial diversity. The results of this study reinforce that MD adherence results in a better glycemic control in subjects with T2D. Changes in gut bacterial richness caused by MD adherence may be relevant in mediating the metabolic impact of this dietary intervention.
- Polymerase Chain Reaction Screening for Fungemia and/or Invasive Fungal Infections in Patients with Hematologic MalignanciesPublication . Ribeiro, P; Costa, F; Monteiro, A; Caldas, J; Silva, M; Ferreira, G; Veiga, J; Sousa, MO; Viegas, MP; Santos, E; Gonçalves, AJ; Botelho de Sousa, AINTRODUCTION: Invasive fungal infections (IFIs) are a life-threatening complication in patients with hematologic malignancies, mainly in acute leukemia patients, following chemotherapy. IFI incidence is increasing, and associated mortality remains high due to unreliable diagnosis. Antifungal drugs are often limited by inadequate antimicrobial spectrum and side effects. Thus, the detection of circulating fungal DNA has been advocated as a rapid, more sensitive diagnostic tool. PATIENTS AND METHODS: Between June 01 and January 03, weekly blood samples (1,311) were screened from 193 patients undergoing intensive myelosuppressive or immunosuppressive therapy. IFI cases were classified according to European Organization for Research and Treatment of Cancer/Mycoses Study Group criteria. Fungal DNA was extracted from whole blood and amplified using polymerase chain reaction (PCR) published primers that bind to the conserved regions of the fungal 18S rRNA gene sequence. In our study, two or more consecutive positive samples were always associated with fungal disease. RESULTS: PCR screening predicted the development of IFI to be 17 days (median). This test had a specificity of 91.1% and a sensitivity of 75%. IFI incidence was 7.8%. DISCUSSION: Therefore, our results confirm the potential usefulness of PCR serial screening and the clinical applicability in everyday routine. PCR screening offers a noninvasive repeatable aid to the diagnosis of IFI.
- Screening a Targeted Panel of Genes by Next-Generation Sequencing Improves Risk Stratification in Real World Patients with Acute Myeloid LeukemiaPublication . Matos, S; Bernardo, P; Esteves, S; Botelho de Sousa, A; Lemos, M; Ribeiro, P; Silva, M; Nunes, A; Lobato, J; Frade, MJ; Gomes da Silva, M; Chacim, S; Mariz, J; Esteves, G; Raposo, J; Espadana, A; Carda, J; Barbosa, P; Martins, V; Carmo-Fonseca, M; Desterro, JAlthough mutation profiling of defined genes is recommended for classification of acute myeloid leukemia (AML) patients, screening of targeted gene panels using next-generation sequencing (NGS) is not always routinely used as standard of care. The objective of this study was to prospectively assess whether extended molecular monitoring using NGS adds clinical value for risk assessment in real-world AML patients. We analyzed a cohort of 268 newly diagnosed AML patients. We compared the prognostic stratification of our study population according to the European LeukemiaNet recommendations, before and after the incorporation of the extended mutational profile information obtained by NGS. Without access to NGS data, 63 patients (23%) failed to be stratified into risk groups. After NGS data, only 27 patients (10%) failed risk stratification. Another 33 patients were re-classified as adverse-risk patients once the NGS data was incorporated. In total, access to NGS data refined risk assessment for 62 patients (23%). We further compared clinical outcomes with prognostic stratification, and observed unexpected outcomes associated with FLT3 mutations. In conclusion, this study demonstrates the prognostic utility of screening AML patients for multiple gene mutations by NGS and underscores the need for further studies to refine the current risk classification criteria.