The activity of methylene blue against asexual and sexual stages of Plasmodium vivax

Methylene blue (MB) is an alternative for combating drug-resistant malaria parasites. Its transmission-blocking potential has been demonstrated in vivo in murine models, in vitro, and in clinical trials. MB shows high efficacy against Plasmodium vivax asexual stages; however, its efficacy in sexual stages is unknown. In this study, we evaluated the potential of MB against asexual and sexual forms of P. vivax isolated from the blood of patients residing in the Brazilian Amazon. An ex vivo schizont maturation assay, zygote to ookinete transformation assay, direct membrane feed assay (DMFA), and standard membrane feed assay (SMFA) using P. vivax gametocytes with MB exposure were performed. A cytotoxicity assay was also performed on freshly collected peripheral blood mononuclear cells (PBMCs) and the hepatocyte carcinoma cell line HepG2. MB inhibited the P. vivax schizont maturation and demonstrated an IC50 lower than that of chloroquine (control drug). In the sexual forms, the MB demonstrated a high level of inhibition in the transformation of the zygotes into ookinetes. In the DMFA, MB did not considerably affect the infection rate and showed low inhibition, but it demonstrated a slight decrease in the infection intensity in all tested concentrations. In contrast, in the SMFA, MB was able to completely block the transmission at the highest concentration (20 µM). MB demonstrated low cytotoxicity to fresh PBMCs but demonstrated higher cytotoxicity to the hepatocyte carcinoma cell line HepG2. These results show that MB may be a potential drug for vivax malaria treatment

Temporal patterns of cytokine and injury biomarkers in hospitalized COVID-19 patients treated with methylprednisolone

BackgroundThe novel coronavirus disease 2019 (COVID-19) presents with complex pathophysiological effects in various organ systems. Following the COVID-19, there are shifts in biomarker and cytokine equilibrium associated with altered physiological processes arising from viral damage or aggressive immunological response. We hypothesized that high daily dose methylprednisolone improved the injury biomarkers and serum cytokine profiles in COVID-19 patients.MethodsInjury biomarker and cytokine analysis was performed on 50 SARS-Cov-2 negative controls and 101 hospitalized severe COVID-19 patients: 49 methylprednisolone-treated (MP group) and 52 placebo-treated serum samples. Samples from the treated groups collected on days D1 (pre-treatment) all the groups, D7 (2 days after ending therapy) and D14 were analyzed. Luminex assay quantified the biomarkers HMGB1, FABP3, myoglobin, troponin I and NTproBNP. Immune mediators (CXCL8, CCL2, CXCL9, CXCL10, TNF, IFN-γ, IL-17A, IL-12p70, IL-10, IL-6, IL-4, IL-2, and IL-1β) were quantified using cytometric bead array.ResultsAt pretreatment, the two treatment groups were comparable demographically. At pre-treatment (D1), injury biomarkers (HMGB1, TnI, myoglobin and FABP3) were distinctly elevated. At D7, HMGB1 was significantly higher in the MP group (p=0.0448) compared to the placebo group, while HMGB1 in the placebo group diminished significantly by D14 (p=0.0115). Compared to healthy control samples, several immune mediators (IL-17A, IL-6, IL-10, MIG, MCP-1, and IP-10) were considerably elevated at baseline (all p≤0.05). At D7, MIG and IP-10 of the MP-group were significantly lower than in the placebo-group (p=0.0431, p=0.0069, respectively). Longitudinally, IL-2 (MP-group) and IL-17A (placebo-group) had increased significantly by D14. In placebo group, IL-2 and IL-17A continuously increased, as IL-12p70, IL-10 and IP-10 steadily decreased during follow-up. The MP treated group had IL-2, IFN-γ, IL-17A and IL-12p70 progressively increase while IL-1β and IL-10 gradually decreased towards D14. Moderate to strong positive correlations between chemokines and cytokines were observed on D7 and D14.ConclusionThese findings suggest MP treatment could ameliorate levels of myoglobin and FABP3, but appeared to have no impact on HMGB1, TnI and NTproBNP. In addition, methylprednisolone relieves the COVID-19 induced inflammatory response by diminishing MIG and IP-10 levels. Overall, corticosteroid (methylprednisolone) use in COVID-19 management influences the immunological molecule and injury biomarker profile in COVID-19 patients

COVID-19 and Hypercoagulable State: A New Therapeutic Perspective

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COVID-19 e Estado de Hipercoagulabilidade: Uma Nova Perspectiva Terapêutica

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Violacein-Induced Chaperone System Collapse Underlies Multistage Antiplasmodial Activity

Antimalarial drugs with novel modes of action and wide therapeutic potential are needed to pave the way for malaria eradication. Violacein is a natural compound known for its biological activity against cancer cells and several pathogens, including the malaria parasite, Plasmodium falciparum (Pf). Herein, using chemical genomic profiling (CGP), we found that violacein affects protein homeostasis. Mechanistically, violacein binds Pf chaperones, PfHsp90 and PfHsp70-1, compromising the latter's ATPase and chaperone activities. Additionally, violacein-treated parasites exhibited increased protein unfolding and proteasomal degradation. The uncoupling of the parasite stress response reflects the multistage growth inhibitory effect promoted by violacein. Despite evidence of proteotoxic stress, violacein did not inhibit global protein synthesis via UPR activation - a process that is highly dependent on chaperones, in agreement with the notion of a violacein-induced proteostasis collapse. Our data highlight the importance of a functioning chaperone-proteasome system for parasite development and differentiation. Thus, a violacein-like small molecule might provide a good scaffold for development of a novel probe for examining the molecular chaperone network and/or antiplasmodial drug design.publishersversionpublishe

Difference in clinical features of SARS-CoV-2 in pediatric patients before and after emergence of P.1.

BACKGROUND: The P.1 variant is a Variant of Concern announced by the WHO. The present work aimed to characterize the clinical features of pediatric patients with SARS-CoV-2 before and after the emergence of P.1. METHODS: This is a cohort study. Data of symptomatic patients younger than 18 years diagnosed with COVID-19 by PCR tests registered in Painel COVID-19 Amazonas were analyzed. RESULTS: A total of 4080 symptomatic pediatric patients were identified in the database between March 2020 and July 2021, of which 1654 were categorized as pre-P.1 and 978 as P.1-dominant cases, based on the prevalence of P.1 of >90% in the North Region, Brazil. Lower case-fatality rate was observed in non-infants infected during the P.1-dominant period (0.9% vs. 2.2%). In general, patients infected during the P.1-dominant period had less fever (70.8% vs. 74.2%) and less lower respiratory tract symptoms (respiratory distress: 11.8% vs. 18.9%, dyspnea: 27.9% vs. 34.5%) yet higher prevalence of neurological symptoms, headache for example (42.8% vs. 5.9%). CONCLUSIONS: The prevalence of symptoms of COVID-19 can differ across different periods of variant dominance. Lower prevalence of fever during the P.1-dominant period may reduce the effectiveness of symptom-based screening in public premises where laboratory diagnostic tests are not available. IMPACT: The prevalence rate of symptoms of SARS-CoV-2 infection can differ among different variants. The present work documents the difference in the clinical features of SARS-CoV-2 in patients aged below 18 years before and after the emergence of P.1, the first study of its kind. Unlike previous studies that focus solely on hospitalized cases, the present work considers both mild and severe cases. While non-infants had a lower fatality rate, lower prevalence of fever associated with the emergence of P.1 may reduce the effectiveness of symptom-based screening in public premises where laboratory diagnostic tests are not available

Chemoresistance of Plasmodium falciparum and Plasmodium vivax parasites in Brazil: consequences on disease morbidity and control

In Brazil, malaria still remains a clinically important febrile syndrome for local populations and travelers, occurring mostly in the Amazon Basin. This review aims to report the main efforts employed to control this disease since the 1940s and the emergence of Plasmodium falciparum and Plasmodium vivax chemoresistance to chloroquine and sulphadoxine-pyrimethamine among other drugs. Additionally, in vivo, in vitro and molecular studies as well as malaria chemoresistance consequences on disease morbidity and policy treatment guidelines were commented

Diabetes insipidus secondary to tuberculous meningoencephalitis with hypothalamic involvement extending to the hypophysis: a case report

Abstract The involvement of Mycobacterium tuberculosis in the central nervous system (CNS) is an uncommon and devastating manifestation of tuberculosis. We report a case of disseminated tuberculosis presenting as meningoencephalitis, hypothalamic involvement with extension to the hypophysis, and secondary insipidus diabetes diagnosed at autopsy