92 results match your criteria: "Instituto de Investigaciones Clinicas Dr. Americo Negrette[Affiliation]"

Role of the receptor for advanced glycation end products in the severity of SARS-CoV-2 infection in diabetic patients.

Diabetol Int

October 2024

Universidad Nacional del Chimborazo, Facultad de Ciencias de la Salud, Riobamba, Ecuador.

Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, is a severe disease in older adults and in individuals with associated comorbidities such as diabetes mellitus. Patients with diabetes infected with SARS-CoV-2 are more likely to develop severe pneumonia, hospitalization, and mortality compared with infected non-diabetic patients During diabetes, hyperglycemia contributes to the maintenance of a low-grade inflammatory state which has been implicated in the microvascular and macrovascular complications associated with this pathology. The receptor for advanced glycation end products (RAGE) is a multi-ligand pattern recognition receptor, expressed on a wide variety of cells, which participates as an important mediator of inflammatory responses in many diseases, including lung diseases.

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Role of Gut Microbiota in Dengue.

Rev Med Virol

September 2024

Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Dengue is a disease caused by a flavivirus (DENV) and transmitted by the bite of a mosquito, primarily the Aedes aegypti and Aedes albopictus species. Previous studies have demonstrated a relationship between the host gut microbiota and the evolution of dengue. It seems to be a bidirectional relationship, in which the DENV can affect the microbiota by inducing alterations related to intestinal permeability, leading to the release of molecules from microbiota dysbiosis that can influence the evolution of dengue.

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Role of angiotensin II in cellular entry and replication of dengue virus.

Arch Virol

May 2024

Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Previous studies have demonstrated the relevance of several soluble molecules in the pathogenesis of dengue. In this regard, a possible role for angiotensin II (Ang II) in the pathophysiology of dengue has been suggested by the observation of a blockade of Ang II in patients with dengue, increased expression of molecules related to Ang II production in the plasma of dengue patients, increased expression of circulating cytokines and soluble molecules related to the action of Ang II, and an apparent relationship between DENV, Ang II effects, and miRNAs. In addition, in ex vivo experiments, the blockade of Ang II AT1 receptor and ACE-1 (angiotensin converting enzyme 1), both of which are involved in Ang II production and its function, inhibits infection of macrophages by DENV, suggesting a role of Ang II in viral entry or in intracellular viral replication of the virus.

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Possible role of metformin as an antidepressant in diabetes.

J Affect Disord

April 2024

Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela. Electronic address:

Objective: Metformin (MET) is a drug used in the treatment of type 2 diabetes due to its insulin receptor sensitizing properties and anti-hepatic gluconeogenesis effect. One of the comorbidities in diabetes is the depression. This review aimed at summarizing the results of the available MET, depression and diabetes studies to clarify the possible role of MET in the depression during diabetes.

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Angiotensin II and post-streptococcal glomerulonephritis.

Clin Exp Nephrol

May 2024

Facultad de Medicina, Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Universidad del Zulia, Apartado Postal: 23, MaracaiboZulia, 4001-A, Venezuela.

Background: Post-streptococcal glomerulonephritis (PSGN) is a consequence of the infection by group A beta-hemolytic streptococcus. During this infection, various immunological processes generated by streptococcal antigens are triggered, such as the induction of antibodies and immune complexes. This activation of the immune system involves both innate and acquired immunity.

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Apoptosis in post-streptococcal glomerulonephritis and mechanisms for failed of inflammation resolution.

Pediatr Nephrol

June 2024

Instituto de Investigaciones Clínicas "Dr. Américo Negrette," Facultad de Medicina, Universidad del Zulia, Apartado Postal: 23, Maracaibo, 4001-A, Zulia, Venezuela.

Post-streptococcal glomerulonephritis is a condition resulting from infection by group A beta-hemolytic streptococcus. The main mechanism involves the formation of immune complexes formed in the circulation or in situ on the glomerular basement membrane, which activates complement and causes various inflammatory processes. Cellular mechanisms have been reported in the induction of kidney damage represented by the infiltration of innate cells (neutrophils and monocyte/macrophages) and adaptive cells (CD4 + lymphocytes and CD8 + lymphocytes) of the immune system.

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Angiotensin II and dengue.

Arch Virol

June 2023

Department of Anatomy, Physiology and Pharmacology, School of Veterinary Medicine, Saint George's University, True Blue, West Indies, Grenada.

Dengue is a disease caused by a flavivirus that is transmitted principally by the bite of an Aedes aegypti mosquito and represents a major public-health problem. Many studies have been carried out to identify soluble factors that are involved in the pathogenesis of this infection. Cytokines, soluble factors, and oxidative stress have been reported to be involved in the development of severe disease.

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Dengue fever is a serious and growing public health problem in Latin America and elsewhere, intensified by climate change and human mobility. This paper reviews the approaches to the epidemiological prediction of dengue fever using the One Health perspective, including an analysis of how Machine Learning techniques have been applied to it and focuses on the risk factors for dengue in Latin America to put the broader environmental considerations into a detailed understanding of the small-scale processes as they affect disease incidence. Determining that many factors can act as predictors for dengue outbreaks, a large-scale comparison of different predictors over larger geographic areas than those currently studied is lacking to determine which predictors are the most effective.

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Cardiovascular complications are the main cause of mortality and morbidity in the diabetic patients, in whom changes in myocardial structure and function have been described. Numerous molecular mechanisms have been proposed that could contribute to the development of a cardiac damage. In this regard, angiotensin II (Ang II), a proinflammatory peptide that constitutes the main effector of the renin-angiotensin system (RAS) has taken a relevant role.

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C-reactive protein as an effector molecule in Covid-19 pathogenesis.

Rev Med Virol

November 2021

Facultad de Ciencias de la Salud, Departamento de Ciencias Biologicas, Universidad Tecnica de Manabi, Portoviejo, Ecuador.

The current pandemic caused by SARS-CoV-2 virus infection is known as Covid-19 (coronavirus disease 2019). This disease can be asymptomatic or can affect multiple organ systems. Damage induced by the virus is related to dysfunctional activity of the immune system, but the activity of molecules such as C-reactive protein (CRP) as a factor capable of inducing an inflammatory status that may be involved in the severe evolution of the disease, has not been extensively evaluated.

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Camelids (camels, dromedaries, alpacas, llamas, and vicuñas) contain in their serum conventional heterodimeric antibodies as well as antibodies with no light chains (L) in their structure and composed of only heavy chains (H), called as HcAbs (heavy chain antibodies). Variable fragments derived from these antibodies, called as VHH or nanoantibodies (Nbs), have also been described. Since their discovery, Nbs have been widely used in the fields of research, diagnostics, and pharmacotherapy.

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SARS-CoV-2 infection represents a high risk for the elderly: analysis of pathogenesis.

Arch Virol

June 2021

Facultad de Ciencias de la Salud, Universidad Nacional del Chimborazo, Riobamba, Ecuador.

As people get older, age-related alterations occur that lead to increased susceptibility to disease. In the current COVID-19 pandemic, older people are particularly susceptible to a SARS-CoV-2 infection developing into severe disease. The objective of this review was to examine the literature regarding factors that may explain the tendency of this population to develop severe COVID-19.

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In situ immunopathological events in human cervical intraepithelial neoplasia and cervical cancer: Review.

Transl Oncol

May 2021

Instituto de Investigaciones Clínicas Dr. Américo Negrette. Facultad de Medicina, Universidad del Zulia. Maracaibo, Venezuela. Electronic address:

Neoplasia of the cervix represents one of the most common cancers in women. Clinical and molecular research has identified immunological impairment in squamous intraepithelial cervical lesions and cervical cancer patients. The in-situ expression of several cytokines by uterine epithelial cells and by infiltrating leukocytes occurs during the cervical intraepithelial neoplasia and cervical cancer.

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Tetracycline and viruses: a possible treatment for COVID-19?

Arch Virol

January 2021

Facultad de Ciencias Veterinarias, Universidad del Zulia, Maracaibo, Venezuela.

Tetracyclines have been used to treat many bacterial infections. The use of these antibiotics for the treatment of viral diseases dates to the 1960s to 1970s. Over the decades, the effect of tetracyclines on the pathogenesis of viral infections has been demonstrated both clinically and experimentally.

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Acute post-streptococcal glomerulonephritis: analysis of the pathogenesis.

Int Rev Immunol

October 2021

Facultad de Medicina, Cátedra de Inmunología, Escuela de Bioanálisis, Universidad del Zulia, Maracaibo, Venezuela.

Increasing evidence supports a central role of the immune system in acute post streptococcal glomerulonephritis (APSGN), but the current view of how streptococcal biology affects immunity, and vice versa, remains to be clarified. Renal glomerular immune complex deposition is critical in the initiation of APSGN; however, mechanisms previous to immune complex formation could modulate the initiation and the progression of the disease. Initial and late renal events involved in the nephritis can also be related to host factors and streptococcal factors.

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Angiotensin II Induces Increased Myocardial Expression of Receptor for Advanced Glycation End Products, Monocyte/Macrophage Infiltration and Circulating Endothelin-1 in Rats With Experimental Diabetes.

Can J Diabetes

October 2020

Instituto de Investigaciones Clínicas "Dr. Américo Negrette," Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela. Electronic address:

Objectives: It is known that the receptor for advanced glycation end products (RAGE) activation is involved in the pathogenesis of cardiovascular disease in diabetes. Previous studies have shown the presence of angiotensin II (Ang II) in diabetes, suggesting a role for this hormone during the disease. However, the association between RAGE and Ang II during pathologic cardiac remodelling after streptozotocin (STZ)-induced diabetes remains unclear.

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Activated monocytes/macrophages that produce a cytokine storm play an important role in the pathogenesis of dengue. Interleukin-18 (IL-18) is a proinflammatory cytokine produced by monocyte/macrophages that is increased during dengue. Ferritin is an acute-phase reactant and expressed by cells of the reticulo-endothelial system in response to infection by dengue virus.

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Cardiac myofibroblast induces decreased expression of major histocompatibility complex class II (Ia) on rat monocyte/macrophages.

Tissue Cell

October 2018

Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela. Electronic address:

The up-regulation of HLA antigens is important during heart inflammatory events and myofibroblasts may modulate the expression of this molecule in tissues. To test this possibility, the effect of cardiac myofibroblast:macrophage contact and the production of myofibroblast inhibitor factor(s) on the macrophage HLA (Ia) expression were studied. Listeria monocytogenes-elicited Ia + peritoneal macrophages (high Ia expression) were co-cultured with cardiac myofibroblasts for 3 and 7 days (myofibroblast contact).

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Aims: The epidermal growth factor receptor (EGFR) and nucleotide-binding and oligomerization-domain containing 2 (NOD2) are important in cancer and in microbial recognition, respectively. These molecules trigger intracellular signaling pathways inducing the expression of inflammatory genes by NF-kB translocation. Gefitinib (GBTC) and pyrrolidine dithiocarbamate (PDTC) are capable of inhibiting EGFR/NOD2 and NF-kB, respectively.

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This study was aimed to determine the profiles of serum cytokines (IL-1β, TNF-α, IL-4, IL-5) and chemokines (MCP-1: monocyte chemoattract protein-1 and RANTES: regulated on activation normal T cell expressed and secreted) in individuals with an asthmatic versus a non-asthmatic background with bacterial, viral or mixed acute respiratory infection. Asthmatic (n = 14) and non-asthmatic (n = 29) patients with acute viral, bacterial or mixed (bacterial and viruses) respiratory infection were studied. Patients were also analysed as individuals with pneumonia or bronchitis.

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Role of the myeloid differentiation primary response (MYD88) and TIR-domain-containing adapter-inducing interferon-β (TRIF) pathways in dengue.

Life Sci

October 2016

Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Maracaibo, Venezuela.

Aims: Dengue disease courses with high viremia titers and high cytokine production suggesting viral replication and active immune response that could be related to viral evasion. One of the main targets of dengue virus (DENV) is monocyte/macrophage cells; however, little information regarding viral evasive mechanisms and pathway activation in monocytes infected by DENV is available. The aim of this study was to determine the role of myeloid differentiation primary response (MyD88), TIR-domain-containing adapter- inducing interferon-β (TRIF) and NF-kB pathways in viral replication and cytokine production in human monocyte cultures infected by DENV2.

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Background: Pro-inflammatory and oxidative events during brain Venezuelan equine encephalitis virus infection could lead to apoptosis and induce anti-inflammatory responses (increased expression of CD200). The aim of this study was to determine the effect of melatonin on brain apoptosis, oxidative stress, and CD200 molecule in mice and neuroblastoma cultures infected by Venezuelan equine encephalitis virus.

Methods: Mice were infected with 10 median lethal doses (LD50) of Venezuelan equine encephalitis virus, treated with melatonin (500 µg/kg bw; three days before infection and during all experimental time) and sacrificed on days 1, 3, and 5 postinfection.

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Aims: Chronic inflammation in obesity is associated with co-morbidities such as, hyperglycemia, hypertension and hyperlipidemia. Leukocytes play an important role in this inflammation and C-reactive protein (CRP) and Interleukin-2 (IL-2) can be important effectors during the immune response in obesity; however, the initial inflammatory events in obesity remain unclear. The aim of this study was to determine the circulating levels of CRP, IL-2, insulin and adiponectin, their association and the association with leukocyte count in obese individuals without co-morbidities and with or without insulin resistance (IR).

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Losartan and enalapril decrease viral absorption and interleukin 1 beta production by macrophages in an experimental dengue virus infection.

Arch Virol

November 2015

Instituto de Investigaciones Clínicas "Dr. Américo Negrette", Facultad de Medicina, Universidad del Zulia, Apartado Postal 23, Maracaibo, 4001-A, Zulia, Venezuela.

The role of angiotensin II (Ang II) in dengue virus infection remains unknown. The aim of this study was to determine the effect of losartan, an antagonist of the angiotensin II type 1 receptor (AT1 receptor), and enalapril, an inhibitor of angiotensin I-converting enzyme (ACE), on viral antigen expression and IL-1β production in peritoneal macrophages infected with dengue virus type 2. Mice treated with losartan or enalapril and untreated controls were infected intraperitoneally with the virus, and macrophages were analyzed.

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Venezuelan equine encephalitis (VEE) virus causes an acute central nervous system infection in human and animals. Melatonin (MLT), minocycline (MIN) and ascorbic acid (AA) have been shown to have antiviral activities in experimental infections; however, the mechanisms involved are poorly studied. Therefore, the aim of this study was to determine the effects of those compounds on the viral titers, NO production and lipid peroxidation in the brain of mice and neuroblastoma cultures infected by VEE virus.

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