Publications by authors named "Tohru Daikoku"

Article Synopsis
  • - The study examined cases of mother-to-infant transmission of herpes simplex virus (HSV-2) and found that neonatal herpes is rare despite common exposure, focusing on viral factors that contribute to this transmission
  • - It was discovered that infant isolates had more temperature-independent characteristics and mutations in the viral UL13 protein kinase (UL13-PK) compared to maternal isolates, with a higher prevalence of these mutations occurring shortly after birth
  • - Additionally, the research identified elongation factor 1-delta as a target of UL13-PK, suggesting that mutations in this protein are crucial for the virus's adaptation and successful transmission from mother to infant.
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  • Stress and glucocorticoid signaling can lead to neuronal death and mental illness, but the plant flavonoid butein may offer neuroprotection.
  • In experiments with Neuro2A (N2A) cells, butein prevented cell death caused by corticosterone (CORT) and influenced key signaling pathways (MEK-ERK and PI3K-AKT).
  • Butein maintained ERK phosphorylation while affecting AKT signaling, suggesting its protective role against glucocorticoid-induced cell death is linked to these pathways.
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Human phospholipid scramblase 1 (PLSCR1) is strongly expressed in response to interferon (IFN) treatment and viral infection, and it has been suggested to play an important role in IFN-dependent antiviral responses. In this study, we showed that the levels of human cytomegalovirus (HCMV) plaque formation in OUMS-36T-3 (36T-3) cells with high basal expression of PLSCR1 were significantly lower than those in human embryonic lung (HEL) cells with low basal expression of PLSCR1. In addition, the levels of HCMV plaque formation and replication in PLSCR1-knockout (KO) 36T-3 cells were significantly higher than those in parental 36T-3 cells and were comparable to those in HEL cells.

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  • * Vaccination helps prevent VZV infections, and antivirals like acyclovir work by interrupting viral DNA synthesis, with a reduced prevalence of acyclovir-resistant mutants in immunocompromised patients.
  • * Amenamevir is already used in Japan for herpes zoster and, in conjunction with vaccines, is expected to enhance treatment options for resistant viral strains, marking a new era in antiherpes therapy.
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  • Amenamevir is a drug used in Japan to treat herpes zoster and works by inhibiting the helicase-primase enzyme in herpes simplex and varicella-zoster viruses.
  • Acyclovir's effectiveness decreases when treatment is delayed, while amenamevir maintains consistent effectiveness despite timing.
  • The study shows that amenamevir's action is not compromised by the viral replication cycle, making it a strong candidate for treating herpes-related conditions.
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A functional understanding of the relationship between glucocorticoids and neuronal apoptosis induced by the production of reactive oxygen species (ROS) may lead to a novel strategy for the treatment or prevention of depression. Previous reports suggest that butein, a type of flavonoids, may be a potent candidate against depression-related neuronal cell apoptosis caused by oxidative stress; however, the protective effects of butein on damaged corticosterone (CORT)-treated neuronal cells has not been elucidated. In the present study, we examined the protective effect of butein on CORT-induced cytotoxicity and neurite growth during cell differentiation of mouse neuroblastoma Neuro2A (N2A) cells.

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Favipiravir has been developed as an anti-influenza drug and licensed as an anti-influenza drug in Japan. Additionally, favipiravir is being stockpiled for 2 million people as a countermeasure for novel influenza strains. This drug functions as a chain terminator at the site of incorporation of the viral RNA and reduces the viral load.

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4',5,7-trihydroxy-3',5'-dimethoxyflavone (tricin), derived from , has been reported to suppress significantly human cytomegalovirus (HCMV) replication in human embryonic lung (HEL) fibroblast cells. However, the target protein of tricin remains unclear. This study focused on the anti-HCMV activity of tricin in terms of its binding affinity to cyclin-dependent kinase 9 (CDK9).

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Treatment of human embryonic lung fibroblast (HEL) cells with tricin (4', 5, 7-trihydroxy-3', 5'-dimethoxyflavone) following infection with human cytomegalovirus (HCMV) reportedly significantly suppresses HCMV replication. In the present work, the mechanisms for the anti-HCMV effects of tricin in HEL cells were examined. It was found that exposure of HEL cells to tricin inhibited HCMV replication, with concomitant decreases in amounts of transcripts of the CC chemokine RANTES (CCL5)-encoding gene and in expression of the CCL5 protein.

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A novel type of antiviral agent for human cytomegalovirus (HCMV) is required, because the appearance of ganciclovir (GCV) resistant viruses has been reported. Tricin (4',5,7-trihydroxy-3',5'-dimethoxyflavone) has been shown to suppress significantly HCMV replication in human embryonic lung (HEL) fibroblast cells. Recently, we revealed that the action of tricin is different from that of GCV and cyclin-dependent kinase 9 (CDK9) is one of the target proteins of tricin.

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We previously reported that treatment with tricin (4',5,7-trihydroxy-3',5'-dimethoxyflavone) after human cytomegalovirus (HCMV) infection significantly suppressed both infectious virion production and HCMV replication in human embryonic lung fibroblast (HEL) cells. Moreover, we recently demonstrated that HCMV infection can increase the expression of CC-motif ligand 2 (CCL2/MCP-1) and of CCR2, a CCL2-specific receptor, effects that can in turn enhance HCMV infection and replication. Hence, we here examined whether the CCL2-CCR2 axis is involved in the anti-HCMV effects of tricin in HEL cells.

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Article Synopsis
  • T-705 (favipiravir) effectively inhibits RNA-dependent RNA polymerases in influenza viruses and has not shown any signs of developing resistance.
  • In a study with poliovirus I (Sabin strain), variants resistant to favipiravir were isolated and analyzed for susceptibility and RNA polymerase mutations.
  • The findings suggest that favipiravir acts as a chain terminator, preventing the lethal mutagenesis seen with ribavirin, and although some mutations occurred, they were detrimental to the virus's RNA polymerase function.
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Intravenous immunoglobulin (IVIG) is used to treat or prevent severe viral infection, especially cytomegalovirus (CMV) infections. IVIG was characterized to understand its interaction with CMV-infected cells. IVIG retarded CMV spread and reduced virus yields depending on the neutralizing (NT) antibody titer.

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Background: The incidence of recurrent herpes zoster (HZ) and the relationship between initial and recurrent HZ are not clear.

Methods: The Miyazaki Dermatologist Society has surveyed ~5000 patients with HZ annually since 1997. A questionnaire regarding HZ and its recurrence was completed by the dermatologists.

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The antiherpetic drugs acyclovir (ACV, valaciclovir) and penciclovir (famciclovir) are phosphorylated by viral thymidine kinase and terminate DNA synthesis. ASP2151 (amenamevir) and foscavir (PFA) directly inhibit viral helicase-primase and DNA polymerase, respectively, and inhibit replication of herpes simplex virus (HSV) and varicella-zoster virus. ACV, ASP2151, and PFA all inhibit HSV with a different mechanism of action and as a consequence, the kinetics of viral DNA accumulation and progeny virus production differ.

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Background: Suppressive therapy in patients with genital herpes has been used in Japan since 2006. Susceptibility and resistance of herpes simplex virus (HSV)-2 to acyclovir were examined in genital isolates from patients receiving suppressive therapy and compared with those from those naïve to acyclovir and receiving episodic treatment with acyclovir.

Objective: The aim of this study was to analyze the effect of acyclovir use on the susceptibility to acyclovir and analysis of the thymidine kinase gene by acyclovir treatment.

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Herpes simplex virus 2 caused a genital ulcer, and a secondary herpetic whitlow appeared during acyclovir therapy. The secondary and recurrent whitlow isolates were acyclovir-resistant and temperature-sensitive in contrast to a genital isolate. We identified the ribonucleotide reductase mutation responsible for temperature-sensitivity by deep-sequencing analysis.

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Article Synopsis
  • A case study reports the simultaneous detection of cytomegalovirus (CMV) in a patient with acute retinal necrosis (ARN) caused by the varicella-zoster virus (VZV).
  • A 65-year-old healthy woman with necrotizing retinitis underwent testing of various samples, revealing both VZV and CMV DNA, though CMV was present in lower quantities.
  • The patient's retinal condition improved rapidly after treatment with acyclovir, suggesting that CMV did not contribute to the ARN in this case, indicating that its reactivation may have been asymptomatic.
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Intravenous immunoglobulin (IVIG) is used to treat severe viral infection, especially varicella-zoster virus (VZV) and cytomegalovirus (CMV) infections. The neutralization antibody titers of eleven IVIG preparations from four companies were examined using VZV and CMV with and without complement. The neutralizing antibody titers of intact IgG preparations were three to six times higher after addition of complement.

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Article Synopsis
  • - T-705 (favipiravir) effectively inhibits RNA polymerases of influenza viruses, specifically targeting the H1N1 strain.
  • - During studies with T-705, nine viral variants showed limited resistance with slight increases in inhibitory concentration, linked to specific amino acid changes in the RNA polymerase genes (PB1, PB2, PA).
  • - The research suggests T-705 does not induce mutations in the viral RNA polymerase that could lead to resistance, as any significant mutation would likely disrupt essential viral functions.
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The herpes simplex virus type 2 (HSV-2) glycoprotein G (gG-2) gene of 106 clinical isolates was analyzed and six isolates were identified with 63 nucleotides comprising 21 amino acids (aa) deleted in the immunodominant region. Compared with strain HG52, variations in the gG-2 gene were found at 276 and 27 sites in nucleotide and aa sequences, respectively, in the 106 strains. Significant variations in both nucleotides and aa were accumulated in the immunodominant region rather than in the other regions (P < 0.

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Drug-resistant cytomegalovirus appears during prolonged anti-cytomegalovirus therapy. Assays for human cytomegalovirus viral protein kinase (UL97) and viral DNA polymerase (UL54) gene mutations conferring drug resistance have been used rather than susceptibility assays to assess clinical specimens. In this study a sensitive system for genotype assay of UL97 and UL54 in clinical specimens with as few as six copies/µg of DNA was developed.

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The physicochemical properties of the optimized microemulsion and the permeating ability of oxyresveratrol in microemulsion were evaluated, and the efficacy of oxyresveratrol microemulsion in cutaneous herpes simplex virus type 1 (HSV-1) infection in mice was examined. The optimized microemulsion was composed of 10% w/w of isopropyl myristate, 35% w/w of Tween 80, 35% w/w of isopropyl alcohol, and 20% w/w of water. The mean particle diameter was 9.

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Antiviral therapy is now one of routine practices and as common as chemotherapy against bacterial infection. Therefore it is important for the clinicians to understand the differences between bacterial and viral infections in order to use antiviral drugs properly. This review focuses the difference of the mechanism of action of antiviral drugs and antibiotics and the importance of host immune status to recover from microbial infection.

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