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1.
J Clin Med ; 13(2)2024 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-38256598

RESUMO

Growing evidence suggests the involvement of adipose tissue in modulating the clinical course of relapsing-remitting multiple sclerosis (RRMS). This study aimed to investigate whether the intake of combined oral contraceptives (COCs) affects body weight and leptin and adiponectin (APN) blood levels in these patients. Clinical data from 62 women (M = 33.23 year) were recorded prior to the initiation of disease-modifying therapy. Patients who were taking COCs at the time of experiencing the first symptoms of disease (COC user) were compared with those who never used these formulations or stopped taking them before disease onset (COC non-user). Bivariate Pearson's correlations and hierarchical multiple linear regressions analysis were conducted. Normalized APN levels were lower in the COC-using patients (p = 0.013). Negative correlations between waist circumference and normalized APN (p = 0.001) were observed only in the COC non-user patients. A longer duration of COC intake was associated with increased body mass index and waist circumference (p = 0.003). Normalized APN predicted the MS Severity Score (MSSS) (p = 0.020), but this correlation was lost in the COC user patients. After adjusting for confounders, only age (p = 0.027) and, later, disease onset (p = 0.014) were correlated with the MSSS. Larger and prospective studies are needed to investigate the interactions of sex steroids with adipose metabolism in modulating disease progression.

3.
Cureus ; 15(10): e46731, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38022304

RESUMO

Symptomatic pericardial effusion occurring as the initial manifestation of Hodgkin's lymphoma is exceedingly uncommon, and there are limited documented instances in the available literature. Pericardial effusion can present various differential diagnoses, and among these, malignancy is an important yet less frequently encountered cause. A heightened level of suspicion is crucial for establishing an accurate diagnosis, particularly when the patient's clinical course deviates from the anticipated trajectory. Through this case, we aim to emphasize the significance of considering lymphoproliferative diseases as a pertinent possibility in the differential diagnosis of pericardial effusion. Additionally, we underscore the importance of promptly reaching a diagnosis, as it can help prevent severe complications and enhance the patient's prognosis.

4.
Sci Adv ; 9(31): eadg2122, 2023 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-37540749

RESUMO

Since the initial spread of severe acute respiratory syndrome coronavirus 2 infection, several viral variants have emerged and represent a major challenge for immune control, particularly in the context of vaccination. We evaluated the quantity, quality, and persistence of immunoglobulin G (IgG) and IgA in individuals who received two or three doses of messenger RNA (mRNA) vaccines, compared with previously infected vaccinated individuals. We show that three doses of mRNA vaccine were required to match the humoral responses of preinfected vaccinees. Given the importance of antibody-dependent cell-mediated immunity against viral infections, we also measured the capacity of IgG to recognize spike variants expressed on the cell surface and found that cross-reactivity was also strongly improved by repeated vaccination. Last, we report low levels of CXCL13, a surrogate marker of germinal center activation and formation, in vaccinees both after two and three doses compared with preinfected individuals, providing a potential explanation for the short duration and low quality of Ig induced.


Assuntos
COVID-19 , Humanos , COVID-19/prevenção & controle , Anticorpos Antivirais , Vacinação , Imunoglobulina G , RNA Mensageiro , Quimiocina CXCL13/genética
5.
Mult Scler Relat Disord ; 76: 104770, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37307690

RESUMO

BACKGROUND: The decision of initiating treatment for multiple sclerosis (MS) with a high-efficacy DMT (HE DMT) or non-high-efficacy DMT (non-HE DMT) is influenced by several factors, including risk perception of patients and physicians. OBJECTIVE: Investigate the influence of physicians' risk perception on decision-making when switching treatments for MS and the reasons for switching. METHODS: Data were drawn from the Adelphi Real-World MS Disease-Specific Program (a retrospective survey) and analysis included people with RMS identified between 2017- 2021. RESULTS: Of 4129 patients with reasons for switch available, 3538 switched from non-HE DMT and 591 from HE DMT. Overall, 4.7% of patients were switched treatment by their physicians due to the risk of malignancies and infections including PML risk. The proportion of switches that were made due to the risk of PML were 23.9% in the HE DMT and 0.5% in the non-HE DMT groups. The top reasons for switching were relapse frequency (non-HE DMT vs HE-DMT: 26.8% vs 15.2%), lack of efficacy (20.9 vs 11.7) and increased number of MRI lesions (20.3% vs 12.4%). CONCLUSIONS: Physicians' risk perception of malignancies and infection excluding PML was not a leading factor when switching treatment. The risk of PML was a key factor, especially for switching patients from HE DMTs. In both groups, lack of efficacy was the key contributing factor for switching. Initiating the treatment with HE DMTs may potentially reduce the number of switches due to sub-optimal efficacy. These findings might help physicians to engage more in discussions with patients about the benefit/risk profile of DMTs.


Assuntos
Esclerose Múltipla , Médicos , Padrões de Prática Médica , Adulto , Feminino , Humanos , Masculino , Estudos Transversais , Pesquisas sobre Atenção à Saúde , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico , Natalizumab/administração & dosagem , Natalizumab/efeitos adversos , Natalizumab/uso terapêutico , Médicos/psicologia , Estudos Retrospectivos , Risco , Resultado do Tratamento , Leucoencefalopatia Multifocal Progressiva/induzido quimicamente , Infecções/induzido quimicamente , Neoplasias/induzido quimicamente
7.
Clin Neuropharmacol ; 46(3): 105-111, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37191564

RESUMO

OBJECTIVES: Cladribine is a selective and oral immunological reconstitution treatment, approved in Europe for very active multiple sclerosis (MS) with relapses. Aims were to assess the safety and effectiveness of cladribine in real-world setting, during treatment follow-up. METHODS: This was a multicentric, longitudinal, observational study with retrospective and prospective data collection of clinical, laboratory, and imaging data. This interim analysis reports data from July 1, 2018 (study onset), to March 31, 2021. RESULTS: A total of 182 patients were enrolled: 68.7% were female; mean age at onset was 30.1 ± 10.0 years, and mean age at first cycle of cladribine treatment was 41.1 ± 12.1; 88.5% were diagnosed with relapse-remitting MS and 11.5% with secondary progressive MS. Mean disease duration at cladribine start was 8.9 ± 7.7 years. Most patients (86.1%) were not naive, and median number of previous disease-modifying therapies was 2 (interquartile range, 1-3). At 12 months, we observed no significant Expanded Disability Status Scale score worsening ( P = 0.843, Mann-Whitney U test) and a significantly lower annualized relapse rate (0.9 at baseline to 0.2; 78% reduction). Cladribine treatment discontinuation was registered in 8% of patients, mainly (69.2%) due to disease activity persistence. Most frequent adverse reactions were lymphocytopenia (55%), infections (25.2%), and fatigue (10.7%). Serious adverse effects were reported in 3.3%. No patient has discontinued cladribine treatment because of adverse effects. CONCLUSION: Our study confirms the clinical efficacy and the safety profile of cladribine for treating MS patients with a long-term active disease in the real-world setting. Our data contribute to the body of knowledge of the clinical management of MS patients and the improvement of related clinical outcomes.


Assuntos
Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Esclerose Múltipla Recidivante-Remitente , Esclerose Múltipla , Humanos , Feminino , Masculino , Cladribina/efeitos adversos , Esclerose Múltipla/tratamento farmacológico , Imunossupressores/efeitos adversos , Portugal/epidemiologia , Estudos Retrospectivos , Centros de Atenção Terciária , Recidiva , Esclerose Múltipla Recidivante-Remitente/tratamento farmacológico
8.
Nat Commun ; 14(1): 1772, 2023 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-36997530

RESUMO

Several millions of individuals are estimated to develop post-acute sequelae SARS-CoV-2 condition (PASC) that persists for months after infection. Here we evaluate the immune response in convalescent individuals with PASC compared to convalescent asymptomatic and uninfected participants, six months following their COVID-19 diagnosis. Both convalescent asymptomatic and PASC cases are characterised by higher CD8+ T cell percentages, however, the proportion of blood CD8+ T cells expressing the mucosal homing receptor ß7 is low in PASC patients. CD8 T cells show increased expression of PD-1, perforin and granzyme B in PASC, and the plasma levels of type I and type III (mucosal) interferons are elevated. The humoral response is characterized by higher levels of IgA against the N and S viral proteins, particularly in those individuals who had severe acute disease. Our results also show that consistently elevated levels of IL-6, IL-8/CXCL8 and IP-10/CXCL10 during acute disease increase the risk to develop PASC. In summary, our study indicates that PASC is defined by persisting immunological dysfunction as late as six months following SARS-CoV-2 infection, including alterations in mucosal immune parameters, redistribution of mucosal CD8+ß7Integrin+ T cells and IgA, indicative of potential viral persistence and mucosal involvement in the etiopathology of PASC.


Assuntos
COVID-19 , SARS-CoV-2 , Humanos , Doença Aguda , Linfócitos T CD8-Positivos , Teste para COVID-19 , Progressão da Doença , Imunoglobulina A
9.
Acta Med Port ; 36(3): 167-173, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36735763

RESUMO

INTRODUCTION: Multiple sclerosis is a disease with a heterogeneous evolution. The early identification of secondary progressive multiple sclerosis is a clinical challenge, which would benefit from the definition of biomarkers and diagnostic tools applicable in the transition phase from relapsing-remitting multiple sclerosis to secondary progressive multiple sclerosis. We aimed to reach a Portuguese national consensus on the monitoring of patients with multiple sclerosis and on the more relevant clinical variables for the early identification of its progression. MATERIAL AND METHODS: A Delphi panel which included eleven Portuguese Neurologists participated in two rounds of questions between July and August of 2021. In the first round, 39 questions which belonged to the functional, cognitive, imaging, biomarkers and additional evaluations were included. Questions for which no consensus was obtained in the first round (less than 80% of agreement), were appraised by the panel during the second round. RESULTS: The response rate was 100% in both rounds and consensus was reached for a total of 33 questions (84.6%). Consensus was reached for monitoring time, evaluation scales and clinical variables such as the degree of brain atrophy and mobility reduction, changes suggestive of secondary progressive multiple sclerosis. Additionally, digital devices were considered tools with potential to identify disease progression. Most questions for which no consensus was obtained referred to the cognitive assessment and the remaining referred to both functional and imaging domains. CONCLUSION: Consensus was obtained for the determination of the monitorization interval and for most of the clinical variables. Most questions that did not reach consensus were related with the confirmation of progression taking into account only one test/domain, reinforcing the multifactorial nature of multiple sclerosis.


Assuntos
Esclerose Múltipla Crônica Progressiva , Esclerose Múltipla , Humanos , Esclerose Múltipla Crônica Progressiva/diagnóstico , Portugal , Progressão da Doença , Biomarcadores
10.
Mult Scler Relat Disord ; 70: 104490, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36621160

RESUMO

BACKGROUND: Strategies recommended to decrease the risk of infection associated with the use of multiple sclerosis disease-modifying treatments include screening and immunization against common viral infections such as varicella-zoster (VZV) and hepatitis B (HBV). However, the data concerning the durability of those vaccine responses and the need for re-test is scarce. OBJECTIVES: We aimed to evaluate HBV and VZV seroprotection loss in MS patients under DMT. METHODS: We conducted a cohort study including patients with basal seroprotective titers against HBV/VZV viruses and a subsequent serology performed at least 3 months apart. We evaluated predictors of seroprotection loss through a binary regression. RESULTS: HBV seroprotection loss occurred in one-fifth of patients in a median interval of 21.3 months. Anti-CD20 treatment (OR 8.559 95%CI 3.467- 21.130, p < 000.1), age at last serology higher or equal to 55 years (OR 7.506, 95% CI 2.473-22.786, p < 0.001) and basal HBsAb titer (OR 0.992, 95%CI 0.987 -0.996, p=0.001) increase the risk of seroprotection loss. VZV seroprotection loss occurred rarely in a median interval of 21.3 months. We could not identify any factor associated with an increased risk of VZV seroprotection loss. CONCLUSIONS: Anti-CD20 drugs are associated with a loss of seroprotection against HBV in a short-interval follow-up.


Assuntos
Vírus da Hepatite B , Hepatite B , Humanos , Vacinas contra Hepatite B/uso terapêutico , Estudos de Coortes , Hepatite B/tratamento farmacológico , Hepatite B/prevenção & controle , Anticorpos Anti-Hepatite B
11.
Pharmacoecon Open ; 7(2): 229-241, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36454397

RESUMO

OBJECTIVES: Ocrelizumab demonstrated significant clinical benefit for the treatment of relapsing (RMS) and primary progressive (PPMS) multiple sclerosis (MS), an incurable disease characterized by disability progression. This study evaluated the clinical and economic impact of ocrelizumab relative to current clinical practice, including other disease-modifying therapies (DMT), available in Portugal. METHODS: Markov models for MS were adapted to estimate the impact of ocrelizumab across three patient populations: treatment-naïve RMS, previously treated RMS, and PPMS. Health states were defined according to the Expanded Disability Status Scale. For RMS, the model further captured the occurrence of relapses and progression to secondary progressive multiple sclerosis (SPMS). A lifetime time-horizon and Portuguese societal perspective were adopted. RESULTS: For RMS patients, ocrelizumab was estimated to maximize the expected time (years) without progression to SPMS (10.50) relative to natalizumab (10.10), dimethyl fumarate (8.64), teriflunomide (8.39), fingolimod (8.38), interferon ß-1a (8.33) and glatiramer acetate (8.18). As the most effective option, with quality-adjusted life year (QALY) gains between 0.3 and 1.2, ocrelizumab was found to be cost-saving relative to natalizumab and fingolimod, and presented incremental cost-effectiveness ratios (ICER) below €16,720/QALY relative to the remaining DMT. For PPMS patients, the ICER of ocrelizumab versus best supportive care was estimated at €78,858/QALY. CONCLUSIONS: Ocrelizumab provides important health benefits for RMS and PPMS patients, comparing favourably with other widely used therapies. In RMS, ocrelizumab was revealed to be either cost-saving or have costs-per-QALY likely below commonly accepted cost-effectiveness thresholds. In PPMS, ocrelizumab fills a clear clinical gap in the current clinical practice. Overall, ocrelizumab is expected to provide good value for money in addressing the need of MS patients.

12.
Cell Death Dis ; 13(8): 741, 2022 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-36030261

RESUMO

In addition to an inflammatory reaction, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)-infected patients present lymphopenia, which we recently reported as being related to abnormal programmed cell death. As an efficient humoral response requires CD4 T-cell help, we hypothesized that the propensity of CD4 T cells to die may impact the quantity and quality of the humoral response in acutely infected individuals. In addition to specific immunoglobulins (Ig)A, IgM, and IgG against SARS-CoV-2 nucleocapsid (N), membrane (M), and spike (S1) proteins, we assessed the quality of IgG response by measuring the avidity index. Because the S protein represents the main target for neutralization and antibody-dependent cellular cytotoxicity responses, we also analyzed anti-S-specific IgG using S-transfected cells (S-Flow). Our results demonstrated that most COVID-19 patients have a predominant IgA anti-N humoral response during the early phase of infection. This specific humoral response preceded the anti-S1 in time and magnitude. The avidity index of anti-S1 IgG was low in acutely infected individuals compared to convalescent patients. We showed that the percentage of apoptotic CD4 T cells is inversely correlated with the levels of specific IgG antibodies. These lower levels were also correlated positively with plasma levels of CXCL10, a marker of disease severity, and soluble Fas ligand that contributes to T-cell death. Finally, we found lower S-Flow responses in patients with higher CD4 T-cell apoptosis. Altogether, these results demonstrate that individuals with high levels of CD4 T-cell apoptosis and CXCL10 have a poor ability to build an efficient anti-S response. Consequently, preventing CD4 T-cell death might be a strategy for improving humoral response during the acute phase, thereby reducing COVID-19 pathogenicity.


Assuntos
Anticorpos Antivirais , Linfócitos T CD4-Positivos , COVID-19 , Imunidade Humoral , Anticorpos Antivirais/imunologia , Apoptose , Linfócitos T CD4-Positivos/citologia , COVID-19/imunologia , Humanos , Imunoglobulina G , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus/imunologia
13.
Cell Death Differ ; 29(8): 1486-1499, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35066575

RESUMO

Severe SARS-CoV-2 infections are characterized by lymphopenia, but the mechanisms involved are still elusive. Based on our knowledge of HIV pathophysiology, we hypothesized that SARS-CoV-2 infection-mediated lymphopenia could also be related to T cell apoptosis. By comparing intensive care unit (ICU) and non-ICU COVID-19 patients with age-matched healthy donors, we found a strong positive correlation between plasma levels of soluble FasL (sFasL) and T cell surface expression of Fas/CD95 with the propensity of T cells to die and CD4 T cell counts. Plasma levels of sFasL and T cell death are correlated with CXCL10 which is part of the signature of 4 biomarkers of disease severity (ROC, 0.98). We also found that members of the Bcl-2 family had modulated in the T cells of COVID-19 patients. More importantly, we demonstrated that the pan-caspase inhibitor, Q-VD, prevents T cell death by apoptosis and enhances Th1 transcripts. Altogether, our results are compatible with a model in which T-cell apoptosis accounts for T lymphopenia in individuals with severe COVID-19. Therefore, a strategy aimed at blocking caspase activation could be beneficial for preventing immunodeficiency in COVID-19 patients.


Assuntos
COVID-19 , Linfopenia , Apoptose , Linfócitos T CD4-Positivos/metabolismo , Caspases/metabolismo , Proteína Ligante Fas , Humanos , SARS-CoV-2 , Linfócitos T/metabolismo , Receptor fas/metabolismo
14.
Front Mol Neurosci ; 15: 1077381, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36590913

RESUMO

Fingolimod is an oral immunomodulatory drug used in the treatment of multiple sclerosis (MS) that may change lipid metabolism. Peroxisome proliferator-activated receptors (PPAR) are transcription factors that regulate lipoprotein metabolism and immune functions and have been implicated in the pathophysiology of MS. CD36 is a scavenger receptor whose transcription is PPAR regulated. The objective of this study was to evaluate whether fingolimod treatment modifies PPAR and CD36 gene expression as part of its action mechanisms. Serum lipoprotein profiles and PPAR and CD36 gene expression levels in peripheral leukocytes were analysed in 17 female MS patients before and at 6 and 12 months after fingolimod treatment initiation. Clinical data during the follow-up period of treatment were obtained. We found that fingolimod treatment increased HDL-Cholesterol and Apolipoprotein E levels and leukocyte PPARγ and CD36 gene expression. No correlations were found between lipid levels and variations in PPARγ and CD36 gene expression. PPARγ and CD36 variations were significantly correlated during therapy and in patients free of relapse and stable disease. Our results suggest that PPARγ and CD36-mediated processes may contribute to the mechanisms of action of fingolimod in MS. Further studies are required to explore the relation of the PPARγ/CD36 pathway to the clinical efficacy of the drug and its involvement in the pathogenesis of the disease.

15.
J Med Cases ; 12(10): 405-410, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34691337

RESUMO

Anti-glomerular basement membrane (anti-GBM) disease and anti-neutrophil cytoplasm antibody (ANCA)-associated vasculitis are the main causes of pulmonary-renal syndrome (PRS). The concurrence of both ANCA - myeloperoxidase (MPO) and proteinase 3 (PR3) - and anti-GBM antibodies has been described, although positivity for all three antibodies has rarely been reported. The natural history of triple-positive patients as well as the best therapeutic approach remains unknown. We describe a case of an 80-year-old woman that presented to the emergency department with a 3-month history of progressive fatigue, malaise and anorexia, and 5 weeks of cough with blood-streaked sputum and progressive peripheral edema. Through the complementary study, a rare diagnosis of PRS with triple-seropositive for both ANCA (MPO and PR3) and anti-GBM antibodies was made in a patient with untreated chronic hepatitis B virus infection. She was treated with glucocorticoid, cyclophosphamide, plasma exchange and entecavir, with pulmonary recovery. Renal function did not improve. After 2 years, the patient is still in dialysis, but did not have relapse of alveolar hemorrhage and ANCA and anti-GBM antibody titers remain negative. The authors intend to warn to PRS, in particular this rare cause, since delaying diagnosis can lead to significant morbidity and mortality for patients.

16.
Front Immunol ; 12: 613422, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33679753

RESUMO

Hyper-inflammatory responses induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are a major cause of disease severity and death. Predictive prognosis biomarkers to guide therapeutics are critically lacking. Several studies have indicated a "cytokine storm" with the release of interleukin-1 (IL-1), IL-6, and IL-8, along with tumor necrosis factor alpha (TNFα) and other inflammatory mediators. Here, we proposed to assess the relationship between IL-6 and outcomes of patients with coronavirus disease 2019 (COVID-19). Our cohort consisted of 46 adult patients with PCR-proven SARS-CoV-2 infection admitted in a COVID-19 ward of the Hospital de Braga (HB) from April 7 to May 7, 2020, whose IL-6 levels were followed over time. We found that IL-6 levels were significantly different between the disease stages. Also, we found a significant negative correlation between IL-6 levels during stages IIb and III, peripheral oxygen saturation (SpO2), and partial pressure of oxygen in arterial blood (PaO2), showing that IL-6 correlates with respiratory failure. Compared to the inflammatory markers available in the clinic routine, we found a positive correlation between IL-6 and C-reactive protein (CRP). However, when we assessed the predictive value of these two markers, IL-6 behaves as a better predictor of disease progression. In a binary logistic regression, IL-6 level was the most significant predictor of the non-survivors group, when compared to age and CRP. Herein, we present IL-6 as a relevant tool for prognostic evaluation, mainly as a predictor of outcome.


Assuntos
COVID-19 , Síndrome da Liberação de Citocina , Interleucina-6/sangue , SARS-CoV-2/metabolismo , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Proteína C-Reativa/metabolismo , COVID-19/sangue , COVID-19/mortalidade , Síndrome da Liberação de Citocina/sangue , Síndrome da Liberação de Citocina/mortalidade , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue
17.
Mult Scler Relat Disord ; 50: 102859, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33652232

RESUMO

HBV screening and immunization is recommended in all MS patients and is mandatory before the start of some DMT. However, studies evaluating the immune response to HBV vaccine in MS patients are scarce. We aimed to evaluate the seroprotection rate following HBV immunization in MS patients and to assess if older age and DMT-treatment influenced seroprotection. We conducted a cohort study between 2016 and 2020 and compared the immune response to HBV vaccine in MS patients under different DMTs and in patients 50 years old or younger and older than 50. We found that patients under non-injectable DMT presented lower rates of seroprotection comparing to patients under injectable DMT's or without treatment. In patients older than 50, although the seroprotection rate was similar to the remaining patients, the antibody anti-HBV surface antigen titers following HBV immunization were lower and patients were more likely to require a 4th dose of the vaccine to achieve seroprotection. Our findings highlight to need to consider HBV immunization in MS patients early in the disease course, in order to ensure a proper immune response to the vaccine.


Assuntos
Anticorpos Anti-Hepatite B , Vírus da Hepatite B , Idoso , Estudos de Coortes , Vacinas contra Hepatite B , Humanos , Pessoa de Meia-Idade , Soroconversão , Vacinação
18.
Materials (Basel) ; 14(4)2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33562437

RESUMO

Selective laser melting (SLM) is an additive manufacturing process for producing metallic components with complex geometries. A drawback of this process is the process-inherent poor surface finish, which is highly detrimental in materials submitted to fatigue loading situations. The goal of this work is to analyze the fatigue behavior of Ti-6Al-4V specimens with internal axial channels under the following different conditions: hole drilled, hole as manufactured, and hole threaded M4 × 0.7. All the cases studied showed a lower fatigue performance as compared with solid samples due to the surface roughness and geometry effect that produced a surface stress concentration leading to a reduction in fatigue strength. The fractography revealed that crack initiation occurred from the internal surface in all specimens with internal channel mostly from defects as unfused particles and lack of fusion zones, while for the solid specimens crack initiation was observed from the external surface due to insufficient fusion defect. The application of the Smith-Watson-Topper energy-based parameter was revealed to be a good tool for fatigue life prediction of the different series studied.

19.
Emerg Microbes Infect ; 10(1): 223-225, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33467983

RESUMO

Buruli ulcer (BU) is a devastating skin mycobacterial infection characterized by extensive cell death, which was previously suggested to be mediated by Bcl2-like protein 11 (BIM, encoded by the BCL2L11 gene). We here report the association of genetic variants in BCL2L11 with ulcerative forms of the disease in a cohort of 618 Beninese individuals. Our results show that regulation of apoptosis in humans contributes to BU lesions associated with worse prognosis, prompting for further investigation on the implementation of novel methods for earlier identification of at-risk patients.


Assuntos
Proteína 11 Semelhante a Bcl-2/genética , Úlcera de Buruli/genética , Proteína 11 Semelhante a Bcl-2/metabolismo , Úlcera de Buruli/metabolismo , Úlcera de Buruli/microbiologia , Estudos de Coortes , Predisposição Genética para Doença , Variação Genética , Humanos , Mycobacterium ulcerans/fisiologia , Polimorfismo de Nucleotídeo Único
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