Publications by authors named "Samir M M Casseb"

Identifying mutations in cancer-associated genes to guide patient treatments is essential for precision medicine. Circulating tumor DNA (ctDNA) offers valuable insights for early cancer detection, treatment assessment, and surveillance. However, a key issue in ctDNA analysis from the bloodstream is the choice of a technique with adequate sensitivity to identify low frequent molecular changes.

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Dengue virus (DENV) is a major global health concern, causing millions of infections annually. Understanding the cellular response to DENV infection is crucial for developing effective therapies. This study provides an in-depth analysis of the cellular response to Dengue virus (DENV) infection, with a specific focus on the interplay between microRNAs (miRNAs), apoptosis, and viral load across different DENV serotypes.

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The objective of this article was to verify associations between the SNPs rs3775291 (Cytosine [C]>Thymine [T]) and rs3775290 (C>T) of in professionals from Health Institutions (HI) who worked during the first pandemic wave and COVID-19. A case-control study was carried out with workers from HI in Belém-PA, Brazil, divided into symptomatology groups (Asymptomatic-AS, =91; and Symptomatic-SI, =121), and severity groups, classified by Chest CT scan (symptomatic with lung involvement - SCP, =34; symptomatic without lung involvement - SSP, =8). Genotyping was performed by Sanger sequencing and statistical analysis was performed using the SPSS program.

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COVID-19 is an infectious disease caused by coronavirus 2 of the severe acute syndrome (SARS-CoV-2). Single nucleotide polymorphisms (SNPs) in genes, such as , responsible for an effective human immune response, can change the course of infection. The objective of this article was to verify associations between epidemiological factors and SNP rs3804100 (Thymine [T] > Cytosine [C]) in professionals from Health Institutions (HI) who worked during the first pandemic wave and COVID-19.

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Natural compounds with pharmacological activity, flavonoids have been the subject of an exponential increase in studies in the field of scientific research focused on therapeutic purposes due to their bioactive properties, such as antioxidant, anti-inflammatory, anti-aging, antibacterial, antiviral, neuroprotective, radioprotective, and antitumor activities. The biological potential of flavonoids, added to their bioavailability, cost-effectiveness, and minimal side effects, direct them as promising cytotoxic anticancer compounds in the optimization of therapies and the search for new drugs in the treatment of cancer, since some extensively antineoplastic therapeutic approaches have become less effective due to tumor resistance to drugs commonly used in chemotherapy. In this review, we emphasize the antitumor properties of tangeretin, a flavonoid found in citrus fruits that has shown activity against some hallmarks of cancer in several types of cancerous cell lines, such as antiproliferative, apoptotic, anti-inflammatory, anti-metastatic, anti-angiogenic, antioxidant, regulatory expression of tumor-suppressor genes, and epigenetic modulation.

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The World Health Organization has estimated the annual occurrence of approximately 392 million dengue virus (DENV) infections in more than 100 countries where the virus is endemic, which represents a serious threat to humanity. DENV is a serologic group with four distinct serotypes (DENV-1, DENV-2, DENV-3, and DENV-4) belonging to the genus , in the family . Dengue is the most widespread mosquito-borne disease in the world.

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Objective: This study verified the replication efficiency of the Rocio virus in a primary culture of mouse neural cells.

Methods: Mixed primary cultures (neurons/glia) obtained from the brains of newborn isogenic BALB/c mice were inoculated with Rocio virus on the 7 th day of culture, and the development of cytopathogenic effects was monitored. The infection was confirmed via immunocytochemistry (anti-ROCV), while viral replication was quantified in infected primary cultures.

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Non-human primates contribute to the spread of yellow fever virus (YFV) and the establishment of transmission cycles in endemic areas, such as Brazil. This study aims to investigate virological, histopathological and immunohistochemical findings in livers of squirrel monkeys ( spp.) infected with the YFV.

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Visceral leishmaniasis (VL), also known as kala-azar, is an anthropozoonotic disease affecting human populations on five continents. Aetiologic agents belong to the Leishmania (L.) donovani complex.

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The COVID-19 pandemic initiated a race to determine the best measures to control the disease and to save as many people as possible. Efforts to implement social distancing, the use of masks, and massive vaccination programs turned out to be essential in reducing the devastating effects of the pandemic. Nevertheless, the high mutation rates of SARS-CoV-2 challenge the vaccination strategy and maintain the threat of new outbreaks due to the risk of infection surges and even lethal variations able to resist the effects of vaccines and upset the balance.

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Understanding the interaction between viruses and ecosystems in areas with or without anthropic interference can contribute to the organization of public health services, as well as prevention and disease control. An arbovirus survey was conducted at Caxiuanã National Forest, Pará, Brazil, where 632 local residents, 338 vertebrates and 15,774 pools of hematophagous arthropods were investigated. Neutralization antibodies of the Venezuelan Equine Encephalitis virus, subtype IIIA, Mucambo virus (MUCV) were detected in 57.

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Cecropins and defensins are the main classes of antimicrobial peptides in the mosquito innate immune system, acting against bacteria, fungi and protozoa. There is a knowledge gap concerning these peptide genes in anopheline mosquitoes from the Brazilian Amazon. Thus, this work aimed to describe molecular techniques for detecting the genes encoding the antimicrobial peptides cecropin A (CecA) and defensin in Anopheles darlingi mosquitoes and to perform molecular phylogeny of the sequenced genes using the maximum likelihood method and Bayesian inference with other species from different geographic areas.

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Peripheral inflammatory stimuli increase proinflammatory cytokines in the bloodstream and central nervous system and activate microglial cells. Here we tested the hypothesis that contrasting environments mimicking sedentary and active lives would be associated with differential microglial morphological responses, inflammatory cytokines concentration, and virus load in the peripheral blood. For this, mice were maintained either in standard (standard environment) or enriched cages (enriched environment) and then subjected to a single (DENV1) serotype infection.

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We identified a strain of Alphacoronavirus 1, FCoV-SB22, from a pool of fecal samples from domestic cats from a rural settlement in the municipality of Santa Bárbara, Pará, Brazil. The nucleotide identity with feline coronavirus was 91.5%.

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Yellow fever virus (YFV) penetrates the skin through the bite of a vector mosquito and spreads to various organs, mainly the liver, where it causes lesions and induces necrosis and apoptosis. We evaluated the mRNA expression of various cytokines and the activation of caspases in HepG2 cells infected with YFV. We observed that interferon-α (IFN-α) expression decreased and IFN-β, transforming growth factor (TGF)-β IIIR, interleukin (IL)-6, and IL-8 expression increased in cells infected with genotype 1.

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A proposed new strain of canine was identified in fecal samples of domestic dogs from a rural community located in the municipality of Peixe-Boi, Pará, Brazil. The nucleotide identity was 92.3% similar to other representatives of the family , genus , and species , which suggests that this is possibly a new strain within this species.

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Zika virus (ZIKV) is an arbovirus belonging to the genus Flavivirus (Flaviviridae). ZIKV infection is associated with alterations in various organs, including the liver, lungs, and kidneys. Studies on the influence of posttranscriptional control on viral infections have demonstrated that microRNAs (miRNAs) interfere with different stages of the replicative cycle of several viruses and may influence the disease outcome.

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Mosquitoes as Sabethes chloropterus, Sabethes glaucodaemon, Sabethes belisarioi are species of medical and epidemiological importance for arboviruses transmission such as yellow fever and St. Louis encephalitis. Despite this, no information about these three species mitochondrial DNA has been found in literature.

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Chikungunya (CHIKV) and Zika (ZIKV) viruses are arboviruses which have recently broken their sylvatic isolation and gone on to spread rampantly among humans in some urban areas of the world, especially in Latin America. Given the lack of effective interventions against such viruses, the aim of this work was to evaluate the antiviral potential of bovine lactoferrin (bLf) in their infections. Through viability, plaque, immunofluorescence and nucleic acid quantification assays, our data show that bLf exerts a dose-dependent strong inhibitory effect on the infection of Vero cells by the aforementioned arboviruses, reducing their infection efficiency by up to nearly 80 %, with no expressive cytotoxicity, and that such antiviral activity occurs at the levels of input and output of virus particles.

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Yellow fever is a zoonotic disease caused by the yellow fever virus (YFV) and transmitted by mosquitoes of the family Culicidae. It is well known that cellular and viral microRNAs (miRNAs) are involved in modulation of viral and cellular gene expression, as well as immune response, and are considered by the scientific community as possible targets for an effective therapy against viral infections. This regulation may be involved in different levels of infection and clinical symptomatology.

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Severe dengue disease is often associated with long-term neurological impairments, but it is unclear what mechanisms are associated with neurological sequelae. Previously, we demonstrated antibody-enhanced dengue disease (ADE) dengue in an immunocompetent mouse model with a dengue virus 2 (DENV2) antibody injection followed by DENV3 virus infection. Here we migrated this ADE model to Callithrix penicillata.

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Background: The Amazon as a whole is the largest reservoir of arboviruses worldwide, while the Brazilian Amazon hosts the largest variety of arboviruses isolated to date. In this study, the results of an indirect sandwich IgG ELISA, standardized for 19 arbovirustypes circulating among horses in Brazilian Amazon, were compared to results of the hemagglutination inhibition test. A screening test assessed the conditional probability distribution and a Pearson linear correlation test determined the correlation strength among the absorbance values recorded for viruses from the same family.

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Although the murine models have the feasibility to reproduce some signs of dengue Virus (DENV) infection, the use of isogenic hosts with polarized immune response patterns does not reproduce the particularities of human disease. Our goal was to investigate the kinetics of peripheral blood biomarkers in immunocompetent Callithrix penicillata non-human primates subcutaneously infected with DENV-3. The viral load of infected animals was determinated by quantitative real time PCR.

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Because an enriched environment (EE) enhances T-cell activity and T-lymphocytes contribute to immunopathogenesis during heterologous dengue virus (DENV) infections, we hypothesised that an EE increases dengue severity. To compare single serotype (SS) and antibody-enhanced disease (AED) infections regimens, serial intraperitoneal were performed with DENV3 (genotype III) infected brain homogenate or anti-DENV2 hyperimmune serum followed 24 h later by DENV3 (genotype III) infected brain homogenate. Compared AED for which significant differences were detected between the EE and impoverished environmental (IE) groups (Kaplan-Meyer log-rank test, p = 0.

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Rocio virus (ROCV) is an encephalitic flavivirus endemic to Brazil. Experimental flavivirus infections have previously demonstrated a persistent infection and, in this study, we investigated the persistence of ROCV infection in golden hamsters (Mesocricetus auratus). The hamsters were infected intraperitoneally with 9.

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