1,403 results match your criteria: "Naval Medical Research Center.[Affiliation]"

Hosts and vectors of scrub typhus in Chile: epidemiological study and molecular analyses of Orientia infection in rodents and rodent-associated mites.

Parasit Vectors

December 2024

Laboratorio Clínico, Facultad de Medicina Clínica Alemana, Clínica Alemana de Santiago, Universidad del Desarrollo, Santiago, Chile.

Candidatus Orientia chiloensis causes scrub typhus over a wide geographical range in southern Chile. The life cycle, including vectors and reservoirs of this novel rickettsial pathogen, is incompletely understood. We analyzed rodent tissue and rodent-associated mite samples collected during a field study in six localities on Chiloé Island, where human scrub typhus cases have occurred.

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Deep vein thrombosis and pulmonary embolism prophylaxis is an important part of trauma care. Despite an increased risk of thrombotic complications, the use of venous thrombosis chemoprophylaxis in penetrating traumatic brain injury (pTBI) patients is met with reluctance from neurosurgeons because of concern for the exacerbation of intracerebral hemorrhage. The objective of this study was to provide initial pre-clinical evidence of the effects of Lovenox (LVX) administration following pTBI with significant intracerebral hemorrhage.

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Arthropod-borne rickettsioses comprise a wide variety of subtypes that are endemic in Cambodia, but there remains very little data on the geographic distribution of the pathogens or their vectors. Surveys were conducted in Koh Kong and Preah Sihanouk Provinces between September 2017 and June 2018 to collect ectoparasites from peridomestic animals and the environment using dragging and flagging methods. Collected ectoparasites were sorted and identified morphologically, then pooled by species, host, and location for molecular detection using Rickettsia genus- and species-specific qPCR and/or multilocus sequence typing (MLST) assays.

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Exploring synergistic and antagonistic interactions in phage-antibiotic combinations against ESKAPE pathogens.

Microbiol Spectr

October 2024

Anti-Infective Research Laboratory, Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan, USA.

In the era of antimicrobial resistance, phage-antibiotic combinations offer a promising therapeutic option, yet research on their synergy and antagonism is limited. This study aims to assess these interactions, focusing on protein synthesis inhibitors and cell envelope-active agents against multidrug-resistant bacterial strains. We evaluated synergistic and antagonistic interactions in multidrug-resistant , , and strains.

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Exposure to high, marginally lethal doses or higher of ionizing radiation, either intentional or accidental, results in injury to various organs. Currently, there is only a limited number of safe and effective radiation countermeasures approved by US Food and Drug Administration for such injuries. These approved agents are effective for only the hematopoietic component of the acute radiation syndrome and must be administered only after the exposure event: currently, there is no FDA-approved agent that can be used prophylactically.

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Dengue NS1 Antibodies Are Associated With Clearance of Viral Nonstructural Protein-1.

J Infect Dis

December 2024

Department of Microbiology, Immunology, and Tropical Medicine, The George Washington University, Washington, District of Columbia, USA.

Background: Dengue vascular permeability syndrome is the primary cause of death in severe dengue infections. The protective versus potentially pathogenic role of dengue nonstructural protein-1 (NS1) antibodies are not well understood. The main goal of this analysis was to characterize the relationship between free NS1 concentration and NS1 antibody titers in primary and secondary dengue infection to better understand the presence and duration of NS1 antibody complexes in clinical dengue infections.

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This study presented the detection and quantification of capsular polysaccharide (CPS) as a biomarker for the diagnosis of melioidosis. After successfully screening four monoclonal antibodies (mAbs) previously determined to bind CPS molecules, the team developed a portable electrochemical immunosensor based on antibody-antigen interactions. The biosensor was able to detect CPS with a wide detection range from 0.

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Hematopoietic acute radiation syndrome (H-ARS) involves injury to multiple organ systems following total body irradiation (TBI). Our laboratory demonstrated that captopril, an angiotensin-converting enzyme inhibitor, mitigates H-ARS in Göttingen minipigs, with improved survival and hematopoietic recovery, as well as the suppression of acute inflammation. However, the effects of captopril on the gastrointestinal (GI) system after TBI are not well known.

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Risk factors affecting the feeding site predilection of ticks on cattle in Ghana.

Exp Appl Acarol

May 2024

Parasitology Department, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Accra, Ghana.

Ticks are important disease vectors affecting animal health and causing substantial economic loss, especially in the tropics and subtropics. To examine the tick burden of cattle and associated risk factors for tick infestation, ticks were collected from 388 cattle within five regions in Ghana. Most of the cattle were males (50.

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Introduction: We sought to determine pre-infection correlates of protection against SARS-CoV-2 post-vaccine inzfections (PVI) acquired during the first Omicron wave in the United States.

Methods: Serum and saliva samples from 176 vaccinated adults were collected from October to December of 2021, immediately before the Omicron wave, and assessed for SARS-CoV-2 Spike-specific IgG and IgA binding antibodies (bAb). Sera were also assessed for bAb using commercial assays, and for neutralization activity against several SARS-CoV-2 variants.

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Despite remarkable scientific progress over the past six decades within the medical arts and in radiobiology in general, limited radiation medical countermeasures (MCMs) have been approved by the United States Food and Drug Administration for the acute radiation syndrome (ARS). Additional effort is needed to develop large animal models for improving the prediction of clinical safety and effectiveness of MCMs for acute and delayed effects of radiation in humans. Nonhuman primates (NHPs) are considered the animal models that reproduce the most appropriate representation of human disease and are considered the gold standard for drug development and regulatory approval.

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Vector-borne pathogen surveillance in a metagenomic world.

PLoS Negl Trop Dis

February 2024

Walter Reed Biosystematics Unit (WRBU), Smithsonian Institution, Museum Support Center, Suitland, Maryland, United States of America.

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First Molecular Identification of Rickettsia aeschlimannii and Rickettsia africae in Ticks from Ghana.

Am J Trop Med Hyg

March 2024

Department of Parasitology, Noguchi Memorial Institute for Medical Research, College of Health Sciences, University of Ghana, Accra, Ghana.

Article Synopsis
  • The study highlights the risk of infection from tick-borne diseases, particularly for people in Ghana, including military personnel and livestock, which serve as hosts for pathogens.
  • Researchers identified and analyzed a total of 1,493 adult ticks from three genera and discovered a significant presence (56.9%) of Rickettsia species using molecular techniques.
  • The first molecular detection of Rickettsia aeschlimannii and Rickettsia africae in these ticks was reported, indicating a pressing need for control measures to mitigate human infections in Ghana and further research into their clinical impact.
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Several filoviruses, including Marburg virus (MARV), cause severe disease in humans and nonhuman primates (NHPs). However, the Egyptian rousette bat (ERB, ), the only known MARV reservoir, shows no overt illness upon natural or experimental infection, which, like other bat hosts of zoonoses, is due to well-adapted, likely species-specific immune features. Despite advances in understanding reservoir immune responses to filoviruses, ERB peripheral blood responses to MARV and how they compare to those of diseased filovirus-infected spillover hosts remain ill-defined.

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The long-term effects of exposure to blast overpressure are an important health concern in military personnel. Increase in amyloid beta (Aβ) has been documented after non-blast traumatic brain injury (TBI) and may contribute to neuropathology and an increased risk for Alzheimer's disease. We have shown that Aβ levels decrease following exposure to a low-intensity blast overpressure event.

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Dual-Antigen Subunit Vaccine Nanoparticles for Scrub Typhus.

Pathogens

November 2023

School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 950 Atlantic Dr. NW, Atlanta, GA 30332, USA.

Article Synopsis
  • The pathogen causing scrub typhus, an acute illness in the Asia-Pacific region, is spread through chigger bites and currently lacks a vaccine.
  • Researchers developed nanoparticles using two specific proteins (47 kD and 56 kD) from the pathogen to create a dual-antigen subunit vaccine.
  • These nanoparticles showed improved immune responses in vaccinated mice, especially with an extra layer of the 56 kD protein, suggesting their potential as an effective vaccine strategy against scrub typhus.
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Diagnostic limitations challenge management of clinically indistinguishable acute infectious illness globally. Gene expression classification models show great promise distinguishing causes of fever. We generated transcriptional data for a 294-participant (USA, Sri Lanka) discovery cohort with adjudicated viral or bacterial infections of diverse etiology or non-infectious disease mimics.

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Objective.: To develop and validate a cell suspension method using Vero 76 cells for culturing Zika virus (ZIKV) based on infection of detached freshly seeded cells.

Material And Methods.

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Resolving chromatin-remodeling-linked gene expression changes at cell-type resolution is important for understanding disease states. Here we describe MAGICAL (Multiome Accessibility Gene Integration Calling and Looping), a hierarchical Bayesian approach that leverages paired single-cell RNA sequencing and single-cell transposase-accessible chromatin sequencing from different conditions to map disease-associated transcription factors, chromatin sites, and genes as regulatory circuits. By simultaneously modeling signal variation across cells and conditions in both omics data types, MAGICAL achieved high accuracy on circuit inference.

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Iron Deposition in the Bone Marrow and Spleen of Nonhuman Primates with Acute Radiation Syndrome.

Radiat Res

December 2023

Division of Radioprotectants, Department of Pharmacology and Molecular Therapeutics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814.

The risk of exposure to high levels of ionizing radiation from nuclear weapons or radiological accidents is an increasing world concern. Partial- or total-body exposure to high doses of radiation is potentially lethal through the induction of acute radiation syndrome (ARS). Hematopoietic cells are sensitive to radiation exposure; white blood cells primarily undergo apoptosis while red blood cells (RBCs) undergo hemolysis.

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Deep phenotyping of the lipidomic response in COVID-19 and non-COVID-19 sepsis.

Clin Transl Med

November 2023

Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

Background: Lipids may influence cellular penetrance by viral pathogens and the immune response that they evoke. We deeply phenotyped the lipidomic response to SARs-CoV-2 and compared that with infection with other pathogens in patients admitted with acute respiratory distress syndrome to an intensive care unit (ICU).

Methods: Mass spectrometry was used to characterise lipids and relate them to proteins, peripheral cell immunotypes and disease severity.

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Introduction: Mild traumatic brain injury (mTBI) caused by repetitive low-intensity blast overpressure (relBOP) in military personnel exposed to breaching and heavy weapons is often unrecognized and is understudied. Exposure to relBOP poses the risk of developing abnormal behavioral and psychological changes such as altered cognitive function, anxiety, and depression, all of which can severely compromise the quality of the life of the affected individual. Due to the structural and anatomical heterogeneity of the brain, understanding the potentially varied effects of relBOP in different regions of the brain could lend insights into the risks from exposures.

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Referral practices are associated with a delay in treatment of symptomatic cholelithiasis and cholecystitis.

Am J Surg

January 2024

Uniformed Services University of the Health Sciences, 4301 Jones Bridge Ave, Bethesda, MD, 20814, USA; Department of Surgery, Walter Reed National Military Medical Center, 8901 Wisconsin Ave, Bethesda, MD, 20814, USA; En Route and Critical Care Research Department, Naval Medical Research Center, 503 Robert Grant Ave, Silver Spring, MD, 20910, USA.

Background: The project was performed to determine if referrals to non-surgical providers after an initial presentation of symptomatic cholelithiasis are associated with a delay in surgical management.

Methods: A single institution chart review of all adult patients who underwent a cholecystectomy from 2015 to 2019 was completed. Quantitative data was analyzed using independent t-tests.

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Wound healing is a complex system including such key players as host, microbe, and treatments. However, little is known about their dynamic interactions. Here we explored the interplay between: (1) bacterial bioburden and host immune responses, (2) bacterial bioburden and wound size, and (3) treatments and wound size, using murine models and various treatment modalities: Phosphate buffer saline (PBS or vehicle, negative control), doxycycline, and two doses of phage mixtures.

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