Temporal patterns of asymptomatic SARS-CoV-2 infection among pediatric population in Japan: A 3-year analysis.

To elucidate the seroprevalence and rate of asymptomatic infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Japanese children, serological analysis was performed using serum samples collected from March 2020 to February 2023. A total of 1493 serum samples were collected during the first study period (March 2020 to February 2021). None of the serum samples was positive for SARS-CoV-2 antibody. In the second period (March 2021 to February 2022), seven of the 1055 patients (0.7%) experienced SARS-CoV-2 infection. The third period (March 2022 to February 2023) was divided into three terms: from March to June 30, 2022; from July to October 2022; and from November 2022 to February 2023. The seroprevalence gradually increased throughout this period, with rates of 6.0%, 18.6%, and 30.4% in the three terms, respectively. Pediatric cases of asymptomatic SARS-CoV-2 infection occurred after the surge of Omicron variants. Since none of the SARS-CoV-2 antibody-positive patients had a previous history of coronavirus disease 2019, the seroprevalence rate in this study may represent the rate of asymptomatic infection.

Anti-angiogenic activity of a novel angiostatin-like plasminogen fragment produced by a bacterial metalloproteinase.

Tumor growth depends on angiogenesis, a process by which new blood vessel are formed from pre-existing normal blood vessels. Proteolytic fragments of plasminogen, containing varying numbers of plasminogen kringle domains, collectively known as angiostatin, are a naturally occurring inhibitor of angiogenesis and inhibit tumor growth. We have developed an "affinity-capture reactor" that enables a single-step method for the production/purification of an angiostatin-like plasminogen fragment from human plasma using an immobilized bacterial metalloproteinase. The resulting fragment, named BL-angiostatin, contains one or two glycosyl chains and the N-terminal PAN module, which are not present in canonical angiostatins tested for cancer treatment. BL-angiostatin inhibited angiogenesis in vitro at 20 nM and the growth of both allograft and human xenograft tumors as well as lung metastasis of primary tumors mice at 0.3-10 mg kg-1. Derivatives of BL angiostatin lacking the PAN module or the terminal sialic acids in the glycosyl chains showed reduced anti-angiogenic activity in vivo, suggesting a role for these functions in activity, possibly via conferring a pharmacokinetic advantage to BL angiostatin compared to recombinant angiostatin lacking both features. These results highlight the potential of BL-angiostatin for therapeutic applications.

Preclinical safety, toxicokinetics and metabolism of BIIB131, a novel prothrombolytic agent for acute stroke.

BIIB131, a small molecule, is currently in Phase 2 for the treatment of acute ischemic stroke. Safety and metabolism of BIIB131 were evaluated following intravenous administration to rats and monkeys. Exposure increased dose-proportionally in rats up to 60 mg/kg and more than dose-proportionally in monkeys at greater than 10 mg/kg accompanied by prolonged half-life and safety findings. The BIIB131 was poorly metabolized in microsomes with no inhibition of CYPs. BIIB131-glucuronide, formed by UGT1A1, accounted for 21.5% metabolism in human hepatocytes and 28-40% in rat bile. In rats, excretion was primarily via the bile. BIIB131 inhibited the hERG and Nav1.5 cardiac channels by 39% but showed no effect on cardiovascular parameters in monkeys. Toxicology findings were limited to reversable hematuria, changes in urinary parameters and local effects. A MTD of 30 mg/kg was established in monkeys, the most sensitive species, at total plasma Cmax and AUC of 6- and 14-fold, respectively, greater than the NOAEL. The Phase 1 study started with intravenous 0.05 mg/kg and ascended to 6.0 mg/kg which corresponded to safety margins of 147- to 0.9-fold (for Cmax) within the linear drug exposure. Thus, the preclinical profile of BIIB131 has been appropriately characterized and supports its further clinical development.

Acute and Postacute Clinical Characteristics of Coronavirus Disease 2019 in Children in Japan.

BACKGROUND: The clinical features of coronavirus disease 2019 (COVID-19) in children have been changing because of the emergence and rapid spread of variants of concern (VOC). The increase in cases infected with VOC has brought concern with persistent symptoms after COVID-19 in children. This survey aimed to analyze the clinical manifestations and persistent symptoms of pediatric COVID-19 cases in Japan. METHODS: We analyzed the clinical manifestations of pediatric COVID-19 cases reported between February 2020 and April 2022 in Japan, using a dedicated database updated voluntarily by the members of the Japan Pediatric Society. Using the same database, we also analyzed persistent symptoms after COVID-19 in children who were diagnosed between February 2020 and November 2021. RESULTS: A total of 5411 and 1697 pediatric COVID-19 cases were included for analyzing clinical manifestations and persistent symptoms, respectively. During the Omicron variant predominant period, the percentage of patients with seizures increased to 13.4% and 7.4% in patient groups 1-4 and 5-11 years of age, respectively, compared with the pre-Delta (1.3%, 0.4%) or Delta period (3.1%, 0.0%). Persistent and present symptoms after 28 days of COVID-19 onset were reported in 55 (3.2%). CONCLUSIONS: Our survey showed that the rate of symptomatic pediatric COVID-19 cases increased gradually, especially during the Omicron variant predominant period, and a certain percentage of pediatric cases had persistent symptoms. Certain percentages of pediatric COVID-19 patients had severe complications or prolonged symptoms. Further studies are needed to follow such patients.

Anti-varicella-zoster virus antibody titers and seroprotection status from before the first dose of varicella vaccination to before entering elementary school in one region in Japan.

OBJECTIVE: We aimed to examine changes in anti-varicella-zoster virus (VZV) antibody titers and seroprotection status from before the first dose of vaccination to before 7 years old entering elementary school in children who received the routine two-dose varicella vaccination. METHODS: Participants were 37 healthy children who received the routine two-dose varicella vaccination at our hospital. A total of five serum samples per child were collected immediately before and 4-6 weeks after each dose of the vaccination and in the year before entry to elementary school. We measured anti-VZV antibody titers by immune adherence hemagglutination (IAHA) method and glycoprotein-based enzyme-linked immunosorbent assay (gpELISA). A positive antibody titer and the seroprotection level were set as ≥2-fold and ≥16-fold, respectively, for IAHA antibody and as ≥50 units and ≥105 units, respectively, for gpELISA-IgG antibody. RESULTS: The rates of IAHA antibody positivity in the five samples (in order of collection) were 0%, 65%, 38%, 100%, and 59%, and the rates of seroprotection were 0%, 43%, 8%, 100%, and 43%. The rates of gpELISA-IgG antibody positivity were 8%, 81%, 89%, 100%, and 100%, and the rates of seroprotection were 5%, 54%, 70%, 100%, and 89%. The mean IAHA antibody titer and mean gpELISA-IgG antibody titer before entering elementary school were both lower than the respective titers obtained after the second vaccination (both p < 0.01). CONCLUSIONS: Routine two-dose varicella vaccination leads to good antibody production, but titers of acquired antibodies decrease before children enter elementary school.

A first-in-human study of the anti-inflammatory profibrinolytic TMS-007, an SMTP family triprenyl phenol.

AIMS: TMS-007, an SMTP family member, modulates plasminogen conformation and enhances plasminogen-fibrin binding, leading to promotion of endogenous fibrinolysis. Its anti-inflammatory action, mediated by soluble epoxide hydrolase inhibition, may contribute to its efficacy. Evidence suggests that TMS-007 can effectively treat experimental thrombotic and embolic strokes with a wide time window, while reducing haemorrhagic transformation. We aim to evaluate the safety, pharmacokinetics and pharmacodynamics of TMS-007 in healthy volunteers. METHODS: This was a randomized, placebo-controlled, double blind, dose-escalation study, administered as a single intravenous infusion of TMS-007 in cohorts of healthy male Japanese subjects. Six cohorts were planned, but only five were completed. In each cohort (n = 8), individuals were randomized to receive one of five doses of TMS-007 (3, 15, 60, 180 or 360 mg; n = 6) or placebo (n = 2). RESULTS: TMS-007 was generally well tolerated, and no serious adverse events were attributed to the drug. A linear dose-dependency was observed for plasma TMS-007 levels. No symptoms of bleeding were observed on brain MRI analysis, and no bleeding-related responses were found on laboratory testing. The plasma levels of the coagulation factor fibrinogen and the anti-fibrinolysis factor α2 -antiplasmin levels were unchanged after TMS-007 dosing. A slight increase in the plasma level of plasmin-α2 -antiplasmin complex, an index of plasmin formation, was observed in the TMS-007 group in cohort 2. CONCLUSIONS: TMS-007 is generally well tolerated and exhibits favourable pharmacokinetic profiles that warrant further clinical development.

Clinical evaluation of a new rapid immunochromatographic test for detection of Bordetella pertussis antigen.

A more rapid and less complicated test to diagnose pertussis is required in clinical settings. We need to detect Bordetella pertussis, which mainly causes pertussis, as early as possible, because pertussis is more likely to become severe in infants, and people around them can easily become a source of infection due to its strong infectivity. Nevertheless, methods that can detect B. pertussis rapidly and efficiently are lacking. Therefore, we developed a new immunochromatographic antigen kit (ICkit) for the early diagnosis of pertussis. The ICkit detects B. pertussis antigens in a nasopharyngeal swab without equipment and provides the result in about 15 min with a simple procedure. Additionally, a prospective study to evaluate the ICkit was conducted in 11 medical institutions, involving 195 cases with suspected pertussis. Compared with the real-time polymerase chain reaction (rPCR), the sensitivity and specificity of the ICkit were 86.4% (19/22) and 97.1% (168/173), respectively. The ICkit detected the antigen in both children and adults. Furthermore, the ICkit detected the antigen until the 25th day from the onset of cough, when rPCR detected the antigen. Thus, the ICkit demonstrated a high correlation with rPCR and would help diagnose pertussis more rapidly and efficiently.

The clinical characteristics of pediatric coronavirus disease 2019 in 2020 in Japan.

BACKGROUND: The COVID-19 pandemic has affected the lives of people of all ages. Most reports on pediatric cases suggest that children experience fewer and milder symptoms than do adults. This is the first nationwide study in Japan focusing on pediatric cases reported by pediatricians, including cases with no or mild symptoms. METHODS: We analyzed the epidemiological and clinical characteristics and transmission patterns of 840 pediatric (<16 years old) COVID-19 cases reported between February and December 2020 in Japan, using a dedicated database which was maintained voluntarily by members of the Japan Pediatric Society. RESULTS: Almost half of the patients (47.7%) were asymptomatic, while most of the others presented mild symptoms. At the time of admission or first outpatient clinic visit, 84.0% of the cases were afebrile (<37.5°C). In total, 609 cases (72.5%) were exposed to COVID-19-positive household members. We analyzed the influence of nationwide school closures that were introduced in March 2020 on COVID-19 transmission routes among children in Japan. Transmission within households occurred most frequently, with no significant difference between the periods before and after declaring nationwide school closures (70.9% and 74.5%, respectively). CONCLUSIONS: COVID-19 symptoms in children are less severe than those in adults. School closure appeared to have a limited effect on transmission. Controlling household transmission from adult family members is the most important measure for prevention of COVID-19 among children.

Surgical spacer placement for proton radiotherapy in locally advanced pancreatic body and tail cancers: initial clinical results.

BACKGROUND: Particle radiotherapy has increasingly gained acceptance for locally advanced pancreatic cancers owing to superior tumor conformity and dosimetry compared to conventional photon radiotherapy. However, the close proximity of the pancreas to the stomach and duodenum leads to radiation-induced gastrointestinal toxicities, which hinder the delivery of curative doses to the tumor. To overcome this problem, a surgical spacer was placed between the tumor and gastrointestinal tract, and subsequent proton radiotherapy was performed in this study. METHODS: Data from 9 patients who underwent surgical spacer placement and subsequent proton radiotherapy were analyzed. The safety and feasibility of the spacer placement surgery were evaluated; the impact of the spacer on dosimetry was also assessed using dose volume histogram (DVH) analyses, before and after surgical spacer placement. RESULTS: Surgical spacer placement and subsequent proton radiotherapy were successfully completed in all cases. Surgical spacer placement significantly improved the dose intensity covering 95%, mean, and minimum doses for the gross tumor volume, and the clinical and planning target volume based on the DVH, while respecting the dose constraints of the gastrointestinal tract. Based on the Common Terminology Criteria for Adverse Events, two patients (22.2%) developed gastrointestinal ulcer (Grade 2) at 1 and 35 months, and one patient (11.1%) developed gastric perforation (Grade 4) at 4 months after proton radiotherapy. CONCLUSIONS: Surgical spacer placement in the locally advanced pancreatic body and tail cancers is relatively safe and technically feasible. Comparing radiation plans, surgical spacer placement seems to improve the dose distribution in the locally advanced pancreatic body and tail cancers, which are close to the gastrointestinal tract.

An Investigation of Japanese Neonatal and Maternal Antibody Status against Pertussis.

To clarify the pertussis immune status of the Japanese population, we investigated levels of serum pertussis toxin (PT)-specific immunoglobulin G (IgG) antibody in infants and mothers between April 2016 and March 2018. A total of 206 infants (n = 22, < 32 weeks of gestational age [wGA]; n = 70, 32-36 wGA; n = 114, ≥ 37 wGA) and 170 mothers were enrolled. The maternal seroprevalence and antibody geometric mean titer (GMT) were 52.4% and 10.7 EU/mL, respectively. The antibody GMT, seroprevalence, and mean ratio of infant to maternal antibody titers of infants at < 32 wGA were 3.2 EU/mL, 13.6%, and 42.5%, respectively, and were significantly lower than those of infants at 32-36 wGA (9.7 EU/mL, 54.3%, and 110.2%) and infants at ≥ 37 wGA (12.1 EU/mL, 57.9%, and 112.6%). Of the 21 infants who underwent a second examination, five were positive in the first examination. Of those five, the GMT for PT had decreased by an average of 52.6% at 4.3- week intervals. In the second examination, two infants were seropositive. Approximately half of the mothers and infants were negative for anti-PT antibody. Thus, new vaccination strategies, such as the vaccination of pregnant women, are needed to prevent pertussis infection in early infancy.

Reliability of direct varicella zoster virus loop-mediated isothermal amplification method for rapid diagnosis of breakthrough varicella.

BACKGROUND: Since patients with breakthrough varicella (BV) have mild symptoms, clinical diagnosis is difficult. In high vaccine coverage area, as BV occurs sporadically, point of care test is required for controlling varicella outbreak. In this study, the reliability of varicella zoster virus (VZV)-loop mediated isothermal amplification (LAMP) was evaluated for the rapid diagnosis of BV. STUDY DESIGN: A total of 328 swab samples collected from patients with suspected varicella were analyzed. For the laboratory diagnosis of varicella, VZV real-time PCR was carried out using DNA extracted from swab samples. Swab samples without DNA extraction were used for VZV-LAMP(direct-LAMP). RESULTS: VZV infection was diagnosed by real-time PCR in 285 cases, including 105 natural varicella cases and 180 BV cases. VZV DNA was detected in 250 (87.8%) of the 285 cases by direct-LAMP. The presence and duration of fever, number of skin eruptions, and VZV DNA load were significantly lower in BV than natural varicella. The sensitivity of direct-LAMP for the diagnosis of varicella and BV was 93.3% and 84.4%, respectively. CONCLUSIONS: Direct LAMP was considered to be useful for rapid diagnosis of BV as it has several advantages such as low cost, ease and rapidity, as compared to real time PCR.

Effects of a Public Subsidy Program for Mumps Vaccine on Reducing the Disease Burden in Nagoya City, Japan.

Nagoya City initiated a public subsidy program for mumps vaccination using either the Torii or Hoshino strains in August 2010. To determine the effects of the program, we used publicly available information from Nagoya City to investigate the changes in immunization rates and numbers of patients who developed post-immunization adverse reactions, including post-vaccinal aseptic meningitis, in the 7 years since its initiation. We also investigated the numbers of mumps patients reported by sentinel sites in a national database during this period. The immunization rate in one-year-old children increased from 24.3% before the program to 91.0% after 7 years. The mean numbers of reported mumps cases per sentinel site in one-year-old to preschool children-the age groups targeted by the program- were 12.9 in the 7 years before the program and 4.93 in the 7 years after initiation of the program, showing a significant decrease of 1/2.6 (p = 0.01). The number of vaccinations during the 6.5-year period was 140,316, with only one case of aseptic meningitis reported (0.7 cases/100,000 vaccinations). No other serious adverse reactions were observed. The present findings demonstrate that the public subsidy program in Nagoya City is an effective and safe measure against mumps in children.

Efficacy of SMTP-7, a small-molecule anti-inflammatory thrombolytic, in embolic stroke in monkeys.

SMTP-7 (Stachybotrys microspora triprenyl phenol-7) is a small molecule that promotes thrombolysis and suppresses inflammation possibly through plasminogen modulation and soluble epoxide hydrolase (sEH) inhibition, respectively. Here, we demonstrate an efficacy of SMTP-7 in a severe embolic stroke model in monkeys. The middle cerebral artery was embolized by an autologous blood clot. Saline, SMTP-7, or tissue-type plasminogen activator (t-PA) (n = 5 in each group) was given after 3 hours, and neurologic deficit scoring and infarct characterization were performed after 24 hours. Hemorrhagic infarct-accompanied premature death was observed for two animals in t-PA group. SMTP-7 treatment significantly reduced the sizes of infarct by 65%, edema by 37%, and clot by 55% compared to saline treatment. Plasma levels of the products of plasminogen activation (plasmin-α2-antiplasmin complex) and sEH reaction (dihydroxyeicosatrienoic acid) in SMTP-7 group were 794% (P < 0.05) and 60% (P = 0.085) compared to saline group, respectively. No significant changes in the plasma levels of MMP-9, CRP, MCP-1, and S100B were found. There was an inverse correlation between plasmin-α2-antiplasmin complex level and infarct volume (r = 0.93, P < 0.05), suggesting a role of thrombolysis in the SMTP-7 action to limit infarct development. In conclusion, SMTP-7 is effective in treating severe embolic stroke in monkeys under conditions where t-PA treatment tends to cause hemorrhagic infarct-associated premature death.

Bordetella pertussis population dynamics and phylogeny in Japan after adoption of acellular pertussis vaccines.

Bordetella pertussis, the causative agent of whooping cough, has experienced a resurgence in the past 15 years, despite the existence of both whole-cell and acellular vaccines. Here, we performed whole genome sequencing analysis of 149 clinical strains, provided by the National Institute of Infectious Diseases (NIID), Japan, isolated in 1982-2014, after Japan became the first country to adopt acellular vaccines against B. pertussis. Additionally, we sequenced 39 strains provided by the Konan Kosei Hospital in Aichi prefecture, Japan, isolated in 2008-2013. The genome sequences afforded insight into B. pertussis genome variability and population dynamics in Japan, and revealed that the B. pertussis population in Japan was characterized by two major clades that divided more than 40 years ago. The pertactin gene was disrupted in about 20 % of the 149 NIID isolates, by either a deletion within the signal sequence (ΔSS) or the insertion of IS element IS481 (prn :: IS481). Phylogeny suggests that the parent clones for these isolates originated in Japan. Divergence dating traced the first generation of the pertactin-deficient mutants in Japan to around 1990, and indicated that strains containing the alternative pertactin allele prn2 may have appeared in Japan around 1974. Molecular clock data suggested that observed fluctuations in B. pertussis population size may have coincided with changes in vaccine usage in the country. The continuing failure to eradicate the disease warrants an exploration of novel vaccine compositions.

Cooperation of Sall4 and Sox8 transcription factors in the regulation of the chicken Sox3 gene during otic placode development.

To elucidate the transcriptional regulation that underlies specification of the otic placode, we investigated the Sox3 downstream enhancer Otic1 of the chicken, the activity of which is restricted to and distributed across the entire otic placode. The 181-bp Otic1 enhancer sequence was dissected into a 68-bp minimal activating sequence, which exhibited dimer enhancer activity in the otic placode and cephalic neural crest, and this was further reduced to a 25-bp Otic1 core sequence, which also showed octamer enhancer activity in the same regions. The Otic1 core octamer was activated by the combined action of Sall4 and the SoxE transcription factors (TFs) Sox8 or Sox9. Binding of Sall4, Sox8 and Sox9 to the Otic1 sequence in embryonic tissues was confirmed by ChIP-qPCR analysis. The core-adjoining 3' side sequences of Otic1 augmented its enhancer activity, while inclusion of the CAGGTG sequence in the immediate 3' end of the 68-bp sequence repressed its enhancer activity outside the otic placode. The CAGGTG sequence likely serves as the binding sites of the repressor TFs δEF1 (Zeb1), Sip1 (Zeb2), and Snail2, all of which are expressed in the cephalic neural crest but not in the otic placode. Therefore, the combination of Sall4-Sox8-dependent activation and CAGGTG sequence-dependent repression determines otic placode development. Although the Otic1 sequence is not conserved in mammals or fishes, the activation mechanism is, as Otic1 was also activated in otic placode tissues developed from mouse embryonic stem cells and transient transgenic zebrafish embryos.

Rotavirus Vaccination Can Be Performed Without Viral Dissemination in the Neonatal Intensive Care Unit.

Background: This study was conducted to assess the transmissibility of rotavirus vaccine strains after rotavirus vaccination in a neonatal intensive care unit (NICU). Methods: Pentavalent (RV5) or monovalent (RV1) rotavirus vaccine was administered to infants admitted to the NICU. Nineteen vaccinated infants and 49 unvaccinated infants whose beds were located in close proximity to the vaccinated infants were enrolled in this study. Dissemination and fecal shedding of vaccine viruses within the NICU were examined using real-time reverse transcription-polymerase chain reaction. Results: Shedding of the vaccine strain was detected in all 19 vaccinated infants. RV5 virus shedding started 1 day after the first vaccination and persisted for 8 days after the first vaccination, and viral shedding terminated by day 5 after administration of the second RV5 dose. The kinetics of RV1 virus shedding differed among vaccinated infants. The duration of RV1 virus shedding was longer after the first vaccination than after the second vaccination. In contrast to the vaccinated infants, no vaccine virus genomes were detected in any of the stool samples collected from the 49 unvaccinated infants. Conclusions: This study is direct evidence of no transmission of rotavirus vaccine strains between vaccinated infants and unvaccinated infants in close proximity within a NICU.

Enhancer Analyses Using Chicken Embryo Electroporation.

Chicken embryo electroporation is a powerful tool used to identify and analyze enhancers involved in developmental gene regulation. In this chapter, the basic procedures and underlying principles of enhancer analysis using chicken embryo electroporation are described in the following steps: (1) identification of enhancers in a wide genomic region, (2) determination of the full enhancer region, (3) definition of the core enhancer regions, and (4) analysis of a functional transcription factor binding sequences in the core region.

Familial acute necrotizing encephalopathy without RANBP2 mutation: Poor outcome.

Most childhood cases of acute necrotizing encephalopathy (ANE) involve neither family history nor recurrence. ANE occasionally occurs, however, as a familial disorder or recurs in Caucasian patients. A mutation of RAN-binding protein 2 (RANBP2) has been discovered in more than one half of familial or recurrent ANE patients. In contrast, there has been no report of this mutation in East Asia. Here, we report the first sibling cases of typical ANE in Japan, with poor outcome. DNA analysis of genes associated with ANE or other encephalopathies, including RANBP2 and carnitine palmitoyl transferase II (CPT2), indicated neither mutations nor disease-related polymorphisms. On literature review, recurrent or familial ANE without the RANBP2 mutation has a more severe outcome and greater predilection for male sex than that with the RANBP2 mutation. This suggests that there are unknown gene mutations linked to ANE.