Matsudaira Kazunari

写真a

Title

Assistant Professor
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Current Affiliation Organization 【 display / non-display 】

  • Duty   University of the Ryukyus   Graduate School of Medicine   Assistant Professor  

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  • Viral load of Torquetenovirus correlates with Sano's score and levels of total bilirubin and aspartate aminotransferase in Kawasaki disease

    Pietro Giorgio Spezia, Kazunari Matsudaira, Fabio Filippini, Takako Miyamura, Keiko Okada, Yoshiro Nagao, Takafumi Ishida, Tetsuya Sano, Mauro Pistello, Fabrizio Maggi, Junichi Hara

    Scientific Reports ( Springer Science and Business Media LLC )  13 ( 1 )   2023.10 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    Abstract Cause of Kawasaki disease (KD) is unknown. KD is often resistant to treatment with intravenous immunoglobulin (IVIG). Sano's score, which is derived from total bilirubin (TBIL), aspartate aminotransferase (AST) and C-reactive protein (CRP), is predictive of IVIG resistance in Japan. A recent study reported that Torquetenovirus (TTV), especially TTV7, was present at a high viral load in the patients with KD. We used PCR to quantify TTV load and amplicon next generation sequencing to detect individual TTV species. We used serum samples that were collected between 2002 and 2005 from 57 Japanese KD patients before IVIG treatment. Correlations between TTV load and Sano's score, the biomarkers that constitute this score, and IVIG resistance were examined. TTV load was positively correlated with Sano's score (P = 0.0248), TBIL (P = 0.0004), and AST (P = 0.0385), but not with CRP (P = 0.6178). TTV load was marginally correlated with IVIG resistance (P = 0.1544). Presence of TTV7 was correlated with total TTV load significantly (P = 0.0231). The correlations between biomarkers for KD and TTV load suggested that TTV may play a role in the pathophysiology of KD. We hypothesize that TTV7 may be associated with a higher total viral load in KD.

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  • Time-series analysis of satellite imagery for detecting vegetation cover changes in Indonesia

    Takuro Furusawa, Takuya Koera, Rikson Siburian, Agung Wicaksono, Kazunari Matsudaira, Yoshinori Ishioka

    Scientific Reports ( Springer Science and Business Media LLC )  13 ( 1 ) 8437   2023.05 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    Abstract Indonesia has one of the world's largest tropical forests; thus, its deforestation and environmental degradation are a global concern. This study is the first to perform comprehensive big data analyses with coherent vegetation criteria to measure the vegetation change at a high temporal resolution (every 16-day period) for 20 years and the high administrative resolution (regency or city) all over Indonesia. The normalized difference vegetation index (NDVI) of the Moderate Resolution Imaging Spectroradiometer is analyzed through state space modeling. The findings reveal that the NDVI increases in almost all regencies, except in urban areas. A high correlation between the NDVI change and the time is observed in Sumatra, Papua, and Kalimantan. The gain of the NDVI values is obvious in the Central and Eastern Java Island. Human activities, such as the expansion of agriculture and forestry and forest conservation policies, are the key factors for the observed pattern.

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  • Macaque progressions: passing order during single-file movements reflects the social structure of a wild stump-tailed macaque group

    Aru Toyoda, Tamaki Maruhashi, Suchinda Malaivijitnond, Kazunari Matsudaira, Zin Arai, Ikki Matsuda, Hiroki Koda

    Primates ( Springer Science and Business Media LLC )    2023.02 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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  • Introgression and mating patterns between white-handed gibbons (Hylobates lar) and pileated gibbons (Hylobates pileatus) in a natural hybrid zone

    Kazunari Matsudaira, Ulrich H. Reichard, Takafumi Ishida, Suchinda Malaivijitnond

    PLOS ONE ( Public Library of Science (PLoS) )  17 ( 3 ) e0264519 - e0264519   2022.03 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    Gibbons (Family Hylobatidae) are a suitable model for exploring hybridization in pair-living primates as several species form hybrid zones. In Khao Yai National Park, Thailand, white-handed gibbons (Hylobates lar) and pileated gibbons (Hylobates pileatus) are distributed parapatrically and hybridize in a narrow zone. Their phenotypic characteristics suggest limited inter-species gene flow, although this has never been assessed. To uncover the history and degree of gene flow between the two species, we studied the genetic structure of gibbons in the hybrid zone by analyzing fecal DNA samples, phenotypic characteristics, vocalizations and individuals' social status. We determined eight autosomal single nucleotide variant (SNV) loci, and mitochondrial DNA (mtDNA) and Y-chromosomal haplotypes of 72 gibbons. We compared these markers with reference types of wild pureblood white-handed gibbons (n = 12) in Kaeng Krachan National Park and pureblood pileated gibbons (n = 4) in Khao Soi Dao Wildlife Sanctuary. Autosomal genotypic analyses confirmed the various levels of mixed ancestry for several adult gibbons with or without atypical phenotypic traits in Khao Yai National Park. In some other adult gibbons, the mixed ancestry was not detected in either autosomal SNVs or their phenotypic traits but the mtDNA. Both male and female adult hybrids formed reproductive units mainly with a phenotypic pureblood partner and many of them produced offspring. Taken together, our results suggest that once hybridization occurs, white-handed-pileated-gibbon hybrids can reproduce with either parental species and that the backcrossing and thus introgression may occur in successive generations, with no drastic changes in phenotypic appearance.

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  • Mating and Reproductive Success in Free-Ranging Stump-Tailed Macaques: Effectiveness of Male–Male Coalition Formation as a Reproductive Strategy

    Aru Toyoda, Tamaki Maruhashi, Yoshi Kawamoto, Kazunari Matsudaira, Ikki Matsuda, Suchinda Malaivijitnond

    Frontiers in Ecology and Evolution ( Frontiers Media SA )  10   802012   2022.03 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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    Male coalition-like formation, recently found in stump-tailed macaques (Macaca arctoides), occurs when several top-ranking males collaboratively guard females to prevent mating with other rival males and actively share secured mating opportunities with their allies. We lack a comprehensive understanding of the proximate mechanisms underlying such male coalitions, e.g., the effect of genetic relatedness. Such cooperative partner choice among males is particularly interesting in animals, such as M. arctoides, that live in matrilineal (female philopatry/male dispersal) society. Theoretically, in such a social system, females, and not males, are often related to each other by kinship. Thus, the occurrence of cooperative behavior between related females are generally common, but it would be rare between unrelated/non-kin males in such matrilineal society. Herein, for the first time, we report detailed copulatory behaviors, including mating and reproductive success, in relation to male coalition-like formation in free-ranging M. arctoides following direct behavioral observation and genetic analysis. We found that coalition-forming male–male alliances often occur among both individuals that are highly related and those that are less related. We identified two groups with different mating strategies, i.e., single-male monopoly and coalition-male monopoly groups. In both groups, nearly 80% of copulations were monopolized by a single male or by coalition males. However, the single-male monopoly strategy allows opportunistic/sneaky copulations by other males with a relatively high probability. Thus, the degree of reproductive success did not reflect mating success. In contrast, the males employing a coalition strategy successfully shared their mating and reproductive success, particularly in the largest group. Compared with single-male monopolized groups, the coalition-male monopoly groups copulated with a considerably more number of females, suggesting that coalition males can effectively guard against opportunistic/sneaky copulation by rival males. We also found that coalition-forming male–male alliances often occur regardless of the degree of kinship/relatedness, indicating the complexity and flexibility inherent in the male social bond of M. arctoides.

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