518 results match your criteria: "Institute of Tropical Medicine (NEKKEN)[Affiliation]"

Background: Leptospirosis is a zoonotic bacterial infection occurring worldwide. It is of particular public health concern due to its global distribution, epidemic potential and high mortality without appropriate treatment. The method for the management of leptospirosis, particularly in severe disease, is clouded by methodological inconsistency and a lack of standardized outcome measures.

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Chronic Fatigue Syndrome (CFS) is a complex disorder characterized by prolonged, unexplained fatigue and challenging diagnosis. We report the case of a 35-year-old Japanese woman with CFS who had experienced chronic fatigue since the age of 11 years. Despite treatment with modafinil, methylphenidate, levocarnitine, and ubiquinone, the symptoms persisted.

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Simple preservation of schistosome eggs with high infectivity up to 12 weeks.

Parasitol Int

December 2024

Department of Parasitology, Institute of Tropical Medicine (NEKKEN), The Joint Usage/Research Center on Tropical Disease, Nagasaki University, Nagasaki, Japan.

The lifecycle of schistosomes must be continuously maintained to clarify and understand this parasite in various aspects in laboratory settings. In the previous studies by other researchers, preservation of schistosome larvae or eggs was attempted by freezing with liquid nitrogen or organic chemicals, but frozen schistosomes were substantially impaired. The present study was conducted to determine whether schistosome eggs can be preserved under a non-frozen condition.

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Downregulation of IRF7-mediated type-I interferon response by LmCen parasites is necessary for protective immunity.

NPJ Vaccines

December 2024

Division of Emerging and Transfusion Transmitted Diseases, CBER, FDA, Silver Spring, MD, 20993, USA.

Leishmaniasis is a tropical disease caused by Leishmania parasites and currently has no licensed vaccines. We developed a dermotropic Leishmania major centrin gene-deleted strain (LmCen) as a live attenuated vaccine. Recent studies have shown that type I interferons (IFNs) play important roles in immunity to parasitic and viral pathogens.

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Malaria rapid diagnostic tests (RDTs) targeting the Plasmodium falciparum histidine-rich protein 2 (PfHRP2) are widely used to diagnose P. falciparum infection. However, reports of P.

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Background: We examined the effectiveness of a community-based intervention package that targeted pregnant women for increasing utilization of maternal health services. The intervention package was implemented in Suhum Municipality, Ghana, from March 2019 to April 2022. The package consisted of: (i) maternal health education by female and male peers; (ii) training existing health workers on maternal health; and (iii) strengthening the local community health management committees.

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Visualizing the Internalization of Marburg Viruslike Particles into Living Cells.

Methods Mol Biol

November 2024

National Research Center for the Control and Prevention of Infectious Diseases, Nagasaki University, Nagasaki, Japan.

Article Synopsis
  • * The research utilizes cells with fluorescent markers for organelles to visualize the VLP entry process, breaking it down into individual steps using bio-probes.
  • * Combining this visual technique with image analysis allows for quantifying the efficiency of each entry step and can be applied for screening antiviral drugs.
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Labeling of miracidium using fluorescent agents to visualize infection of schistosome in intermediate host snails.

Parasitol Int

February 2025

Department of Parasitology, Institute of Tropical Medicine (NEKKEN), The Joint Usage/Research Center on Tropical Disease, Nagasaki University, Nagasaki, Japan.

Schistosomiasis is a parasitic disease affecting more than 250 million people worldwide. Schistosomes infect humans by cercariae penetrating the skin in a freshwater environment. Findings obtained more than 100 years prior showed that miracidium develops into cercaria in freshwater snails, though detailed development dynamics have not been elucidated.

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Accelerating Antimalarial Drug Discovery with a New High-Throughput Screen for Fast-Killing Compounds.

ACS Infect Dis

December 2024

Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki 852-8523, Japan.

The urgent need for rapidly acting compounds in the development of antimalarial drugs underscores the significance of such compounds in overcoming resistance issues and improving patient adherence to antimalarial treatments. The present study introduces a high-throughput screening (HTS) approach using 1536-well plates, employing lactate dehydrogenase (PfLDH) combined with nitroreductase (NTR) and fluorescent probes to evaluate inhibition of the growth of the asexual blood stage of malaria parasites. This method was adapted to efficiently assess the speed of action profiling (SAP) in a 384-well plate format, streamlining the traditionally time-consuming screening process.

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Article Synopsis
  • * The study focused on SBP3, a protein exported by the parasite, which plays a crucial role in the formation of surface protrusions on infected red blood cells that help the parasite adhere to blood vessel cells.
  • * Knocking down SBP3 resulted in hindered parasite growth, fewer adhesion sites, and fewer protrusions, indicating its essential function for the parasite's survival and interaction with the host's cells.
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The corona virus (SARS-CoV-2) pandemic and the resulting long-term neurological complications in patients, known as long COVID, have renewed interest in the correlation between viral infections and neurodegenerative brain disorders. While many viruses can reach the central nervous system (CNS) causing acute or chronic infections (such as herpes simplex virus 1, HSV-1), the lack of a clear mechanistic link between viruses and protein aggregation into amyloids, a characteristic of several neurodegenerative diseases, has rendered such a connection elusive. Recently, we showed that viruses can induce aggregation of purified amyloidogenic proteins via the direct physicochemical mechanism of heterogeneous nucleation (HEN).

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Comparative genomics of Plasmodium yoelii nigeriensis N67 and N67C: genome-wide polymorphisms, differential gene expression, and drug resistance.

BMC Genomics

November 2024

Malaria Functional Genomics Section, Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Disease, National Institutes of Health, Rockville, MD, 20852, USA.

Background: The study of rodent malaria parasites has significantly advanced our understanding of malaria parasite biology and host responses to parasite infections. There are four well-characterized rodent malaria parasite species (Plasmodium yoelii, P. chabaudi, P.

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Malaria remains a key health and economic problem, particularly in sub-Saharan Africa. The emergence of artemisinin drug resistance (ART-R) parasite strains poses a serious threat to the control and elimination of this scourge. This is because artemisinin-based combination therapies (ACTs) remain the first-line treatment in the majority of malaria-endemic regions in Sub-Saharan Africa.

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Reporter parasite lines: valuable tools for the study of Plasmodium biology.

Trends Parasitol

November 2024

Department of Protozoology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Japan. Electronic address:

Article Synopsis
  • The parasite Plasmodium falciparum, responsible for severe malaria, is transmitted through mosquito bites and poses a significant health risk in endemic areas.
  • Researchers have created various transgenic reporter lines of the parasite to express fluorescent and luminescent proteins, enhancing the understanding of its biology.
  • The review covers recent advancements in these reporter lines, their potential for discovering new antimalarial drugs, and points out ongoing questions in malaria research to encourage development of effective treatments.
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The Tokyo 2020 Olympic and Paralympic Games (Games) were held during the height of the coronavirus disease 2019 (COVID-19) pandemic. To detect people infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) early enough to contain the spread and to facilitate the timely arrival of athletes at their game venues, all participating athletes staying in the Olympic Village (up to 14,000) were screened daily for the infection. Toward this aim, a two-step strategy was adopted comprising screening of self-collected saliva samples using a chemiluminescence enzyme immunoassay, followed by confirmatory testing using polymerase chain reaction.

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Surugamides are a group of non-ribosomal peptides produced by Streptomyces spp. Several derivatives possess acyl groups, which are proposed to be attached to a lysine side chain after backbone-macrocyclization during biosynthesis. To date, five different acyl groups have been identified in nature, yet their impacts on biological activity remain underexplored.

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Schistosomiasis, caused by trematodes of genus Schistosoma, is among the most seriously neglected tropical diseases. Although rapid surveillance of risk areas for Schistosoma transmission is vital to control schistosomiasis, the habitat and infection status of this parasite are difficult to assess. Environmental DNA (eDNA) analysis, involving the detection of extra-organismal DNA in water samples, facilitates cost-efficient and sensitive biomonitoring of aquatic environments and is a promising tool to identify Schistosoma habitat and infection risk areas.

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Identification of Chemical Scaffolds That Inhibit the Respiratory Complex Succinate Dehydrogenase.

ACS Infect Dis

October 2024

Department of Microbiology and Immunology, School of Biomedical Sciences, University of Otago, Dunedin 9054, New Zealand.

Article Synopsis
  • Drug-resistant infections are a major health issue, prompting the need for new antibiotics, particularly targeting mycobacterial SDH, which is crucial for energy production and growth in these bacteria.
  • Researchers used biochemical screening and advanced computational methods to find several compounds that inhibit mycobacterial SDH, showing effectiveness against both regular and drug-resistant strains.
  • The study highlights that these SDH inhibitors disrupt mycobacterial metabolism and can enhance the effectiveness of other treatments while helping to prevent the development of resistance.
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SARS-CoV-2 Omicron subvariants progressively adapt to human cells with altered host cell entry.

mSphere

September 2024

Department of Emerging Infectious Diseases, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron variant exhibits high transmissibility with a strong immune escape ability and causes frequent large-scale global infections by producing predominant subvariants. Here, using human upper/lower airway and intestinal cells, we examined the previously dominant BA.1-BA.

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Article Synopsis
  • Entamoeba histolytica is a protozoan parasite causing amebiasis, with a life cycle alternating between symptomatic trophozoites and dormant cysts, presenting a public health challenge due to complex drug treatment issues!* -
  • Recent lipidomics analysis highlighted the unique acyl chain structures in the parasite's lipids, which are crucial for its growth and survival, particularly through the activity of fatty acid elongases (EhFAEs).* -
  • Compounds like flufenacet and cafenstrole were found to inhibit EhFAEs, reducing trophozoite proliferation without affecting human cells, suggesting they could be potential lead candidates for new anti-amebiasis therapies.*
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Marburg virus exploits the Rab11-mediated endocytic pathway in viral-particle production.

Microbiol Spectr

September 2024

National Research Center for the Control and Prevention of Infectious Diseases, Nagasaki University, Nagasaki, Japan.

Filoviruses produce viral particles with characteristic filamentous morphology. The major viral matrix protein, VP40, is trafficked to the plasma membrane and promotes viral particle formation and subsequent viral egress. In the present study, we assessed the role of the small GTPase Rab11-mediated endocytic pathway in Marburg virus (MARV) particle formation and budding.

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Discovery of antimalarial drugs from secondary metabolites in actinomycetes culture library.

Trop Med Health

July 2024

Department of Immune Regulation, SHIONOGI Global Infectious Diseases Division, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Nagasaki, Japan.

Background: Natural products play a key role as potential sources of biologically active substances for the discovery of new drugs. This study aimed to identify secondary metabolites from actinomycete library extracts that are potent against the asexual stages of Plasmodium falciparum (P. falciparum).

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Background: Despite dengue virus (DENV) outbreak in Gabon a decade ago, less is known on the potential circulation of DENV serotypes in the country. Previous studies conducted in some areas of the country, are limited to hospital-based surveys which reported the presence of some cases of serotype 2 and 3 seven years ago and more recently the serotype 1. As further investigation, we extend the survey to the community of Moyen Ogooué region with the aim to assess the presence of the dengue virus serotypes, additionally to characterize chikungunya (CHIKV) infection and describe the symptomatology associated with infections.

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Article Synopsis
  • Acute respiratory infections significantly impact resource-limited countries, including Gabon, where COVID-19 has overshadowed the study of other respiratory viruses.
  • Researchers analyzed 582 nasopharyngeal swabs collected during the pandemic and found that 156 tested positive for various respiratory viruses, with enteroviruses being the most prevalent.
  • This study presents the first genomic sequences of certain respiratory viruses in Gabon, revealing transmission patterns and genetic similarities with strains found in other countries, which enhances understanding of viral circulation in the region.
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