Publications by authors named "Kazuyama Y"

Eight peaks of coronavirus disease 2019 (COVID-19) outbreak occurred in Japan, each associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern. The National Epidemiological Surveillance of Infectious Diseases (NESID) analyzed viral genome sequences from symptomatic patients and submitted the results to GISAID. Meanwhile, commercial testing services occasionally sequence samples from asymptomatic individuals.

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  • - This study assessed how accurately SARS-CoV-2 RNA can be detected in saliva samples, comparing those treated with guanidine and without, against traditional nasopharyngeal swabs (NPS) used as a reference.
  • - Results showed that raw saliva had a 100% sensitivity for detecting the virus, while the sensitivity for saliva treated with guanidine-based and guanidine-free inactivators was lower, at 65.9% and 82.9% respectively.
  • - Despite the reduced sensitivity in treated saliva, the study found that these inactivated samples could still provide reliable results for diagnosing COVID-19, which is beneficial for minimizing the risk of virus transmission.
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  • - The study focused on preventing the spread of COVID-19 from urban areas, specifically Tokyo, to the remote island of Chichijima, which has limited medical resources.
  • - Between September 1, 2020, and March 21, 2021, the island's COVID-19 infection rate was extremely low at 0.015%, and pre-boarding saliva PCR tests were used to screen 8,910 individuals before they boarded ships.
  • - The results showed that seven individuals tested positive for COVID-19, with one confirmed by further testing, leading to their denial of entry and highlighting the effectiveness of such screening for protecting remote communities.
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Isolation of Bordetella pertussis and detection of the pertussis genome are not always successful because of low bacterial loads in adult patients with pertussis. Antibodies against pertussis toxin (PT) are measured but have low sensitivity in vaccinated subjects. There is no reliable diagnostic method at present.

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To design appropriate antiretroviral therapy regimens and avoid the emergence of human immunodeficiency virus (HIV)-1 variants with reduced susceptibility to antiretroviral drugs, genotypic drug-resistance testing (HIV genotyping) is strongly recommended. To monitor the quality of HIV genotyping in Japan, we performed an external quality assessment (EQA), named the Japanese external quality assessment program, to standardize HIV genotyping (JEQS). To accurately evaluate the quality of HIV genotyping, we employed as reference material (RM) a well-characterized sample, in vitro transcribed RNA (trRNA) that includes the HIV gag-pol sequence, and created a JEQS2010 panel consisting of three single variant and three mixed trRNA samples.

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Methicillin-resistant Staphylococcus aureus (MRSA) with exogenous cassette DNA containing the methicillin-resistant gene mecA (SCCmec) poses a problem as a drug-resistant bacterium responsible for hospital- and community-acquired infections. The frequency of MRSA detection has recently been increasing rapidly in Japan, and SCCmec has also been classified more diversely into types I-V. A rapid test is essential for early diagnosis and treatment of MRSA infections, but detection by conventional methods requires at least two days.

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We report a case of a 29-year-old male patient with a generalized adenovirus (AdV) infection after cord blood transplantation (CBT) for acute myelocytic leukemia with maturation at 2nd complete remission. Before engraftment, hemorrhagic cystitis was caused by AdV, which resulted in hydronephrosis, renal failure, and adenoviremia on day 34. Forced diuresis, hemodialysis, withdrawal of cyclosporin A, and administration of gamma-globulin or vidarabine were not effective and the patient died of pulmonary alveolar hemorrhage on day 67.

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A novel, rapid, and noninvasive test (ODK0501) to detect Streptococcus pneumoniae antigen was evaluated in a Japanese multicenter study. ODK0501 uses polyclonal antibodies to detect C polysaccharide of S. pneumoniae from sputum samples by an immunochromatographic assay.

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Chronic active Epstein-Barr virus (EBV) infection is a rare chronic mononucleosis syndrome involving clonally proliferating EBV-infected T-/NK-cells. EBV DNA was quantified in nonpleocytotic cerebrospinal fluid (CSF) of 9 patients. Three patients with neurologic and/or neuroimaging abnormalities showed high CSF copy numbers.

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The antigenic cross-reactive characteristics of herpes B virus and herpes simplex virus (HSV) type 1 (HSV-1) and HSV-2 are responsible for false-positive diagnoses by serological assays in humans and macaques. In the present study, we developed a fluorometric indirect enzyme-linked immunosorbent assay (ELISA) with recombinant herpes B virus glycoprotein D (gD) and HSV-1 and HSV-2 gG (gG-1 and gG-2, respectively) to discriminate between the three primate herpesvirus infections. The secreted form of gD, gDdTM, was used to detect antibody to herpes B virus gD.

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  • Epstein-Barr virus (EBV) causes infectious mononucleosis and can lead to certain cancers, with high prevalence among adults globally but notable geographic variations in infection rates among children.
  • In developing countries, most children are infected by age 1, whereas in Western countries like Japan, infection tends to occur later.
  • A study in Tokyo revealed a significant decline in seropositivity rates among 5-7-year-old children from over 80% pre-1990s to 59% between 1995-1999, suggesting an ongoing delay in primary infection that may impact EBV-related health issues in the future.
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A multiplex polymerase chain reaction (PCR) was developed for the simultaneous detection of Chlamydia pneumoniae, Mycoplasma pneumoniae and Legionella pneumophila. Oligonucleotide primers for the amplification of the DNA of these three organisms were optimized for use in combination in the same reaction. PCR products were detected by the Micro-Chip Electrophoresis Analysis System.

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  • Two patients who received allogeneic stem cell transplants developed chronic graft-versus-host disease (GVHD) after experiencing a localized infection of the varicella-zoster virus (VZV).
  • The localized shingles did not improve with oral valaciclovir but was successfully treated with intravenous aciclovir.
  • Symptoms such as skin rashes, dryness in the eyes and mouth, and liver issues indicated GVHD development, necessitating increased immunosuppressive therapy for management.
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We treated a 73-year-old man who developed a pyothorax-associated pleural lymphoma after a 52-year history of tuberculous pleuritis. The lymphoma was classified histologically as a diffuse large, B-cell type. Epstein-Barr virus (EBV) was identified in the tumor by immunocytochemical and molecular methods.

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It has been reported that the avidity of specific IgG antibody is lower in primary viral infection than in chronic viral infection. However, few studies have been reported on the IgG avidity in hepatitis C virus (HCV) infection. In the present study, 36 patients with antibody to HCV (anti-HCV) were examined for IgG avidity by an enzyme immunoassay with or without urea elution.

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It is well known that herpes simplex virus (HSV) type 2 produces acute meningitis, while HSV type 2 rarely causes recurrent meningitis (Mollaret's meningitis). We report the history of a 40-year-old patient with recurrent HSV type 2 meningitis (Mollaret's meningitis). The patient had seven episodes of meningeal symptoms within a 7-year period.

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In recent years, advances in the diagnosis and treatment of herpes simplex encephalitis (HSE) have been achieved due to the prevalence of antiviral drugs and the introduction of the polymerase chain reaction (PCR) to test the cerebrospinal fluid. The several clinical forms of herpes simplex virus type 1 (HSV-1) infections of the central nervous system (CNS), including acute disseminated encephalomyelitis and brainstem encephalitis, have been clarified. However, fatal, prolonged, or relapsed cases are still observed, and early detection and appropriate treatment is necessary to lead to a good prognosis for these intractable HSE cases.

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We used a real-time PCR assay to measure human cytomegalovirus (HCMV) DNA load in whole blood and plasma of 70 patients who were infected with human immunodeficiency virus type 1. Break points of 3.0 x 10(3) copies/mL in whole blood and 1.

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We developed a new quantitative system for diagnosis of invasive pulmonary aspergillosis (IPA) using real-time automated polymerase chain reaction (PCR). Intra-assay and interassay precision rates for in vitro examination were 2.53% and 2.

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We describe two patients who developed respiratory syncytial virus (RSV) pneumonia after BMT. One died of RSV pneumonia after three courses of steroid pulse therapy. Surprisingly, RSV antigen was identified in the bronchoalveolar lavage fluid (BALF) obtained post mortem.

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The purpose of this study was to assess the usefulness of real-time automated PCR as a quantitative, highly reproducible, and sensitive method to detect cytomegalovirus (CMV) DNA in blood specimens. Intra- and interassay precision rates were 0.89% (small number of copies [L]), 1.

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