Ayumi Hasegawa
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View article: A simplified protocol for vitrification of hamster embryos
A simplified protocol for vitrification of hamster embryos Open
Golden hamsters (Mesocricetus auratus) have been extensively used in biomedical research. With the advent of genome-editing technology, it is now possible to generate gene-knockout hamsters, providing unique research models that cannot be …
View article: Disruption of insulin receptor substrate 2 (IRS2) causes non-obese type 2 diabetes with β-cell dysfunction in the golden (Syrian) hamster
Disruption of insulin receptor substrate 2 (IRS2) causes non-obese type 2 diabetes with β-cell dysfunction in the golden (Syrian) hamster Open
View article: Reduction of H3K9 methylation by G9a inhibitors improves the development of mouse SCNT embryos
Reduction of H3K9 methylation by G9a inhibitors improves the development of mouse SCNT embryos Open
Removal of somatic histone H3 lysine 9 trimethylation (H3K9me3) from the embryonic genome can improve the efficiency of mammalian cloning using somatic cell nuclear transfer (SCNT). However, this strategy involves the injection of histone …
View article: Superovulation with an anti-inhibin monoclonal antibody improves the reproductive performance of rat strains by increasing the pregnancy rate and the litter size
Superovulation with an anti-inhibin monoclonal antibody improves the reproductive performance of rat strains by increasing the pregnancy rate and the litter size Open
Rats are multiparous rodents that have been used extensively in research; however, the low reproductive performance of some rat strains hampers the broader use of rats as a biomedical model. In this study, the possibility of increasing the…
View article: Inter-subspecies mouse F1 hybrid embryonic stem cell lines newly established for studies of allelic imbalance in gene expression
Inter-subspecies mouse F1 hybrid embryonic stem cell lines newly established for studies of allelic imbalance in gene expression Open
Allele-specific monoallelic gene expression is a unique phenomenon and a great resource for analyzing gene regulation. To study this phenomenon, we established new embryonic stem (ES) cell lines derived from F1 hybrid blastocysts from cros…
View article: Disruption of insulin receptor substrate 2 (Irs2) causes non-obese type 2 diabetes with β-cell dysfunction in the golden (Syrian) hamster
Disruption of insulin receptor substrate 2 (Irs2) causes non-obese type 2 diabetes with β-cell dysfunction in the golden (Syrian) hamster Open
Because of the advent of genome-editing technology, gene knockout (KO) hamsters have become attractive research models for diverse diseases in humans. This study established a new KO model of diabetes by disrupting the insulin receptor sub…
View article: Intracytoplasmic sperm injection induces transgenerational abnormalities in mice
Intracytoplasmic sperm injection induces transgenerational abnormalities in mice Open
In vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) are 2 major assisted reproductive techniques (ARTs) used widely to treat infertility. Recently, spermatogonial transplantation emerged as a new ART to restore fertili…
View article: Effect of microgravity on mammalian embryo development evaluated at the International Space Station
Effect of microgravity on mammalian embryo development evaluated at the International Space Station Open
Mammalian embryos differentiate into the inner cell mass (ICM) and trophectoderm at the 8-16 cell stage. The ICM forms a single cluster that develops into a single fetus. However, the factors that determine differentiation and single clust…
View article: Derivation of embryonic stem cells from wild-derived mouse strains by nuclear transfer using peripheral blood cells
Derivation of embryonic stem cells from wild-derived mouse strains by nuclear transfer using peripheral blood cells Open
View article: Superovulation with an anti-inhibin monoclonal antibody improves the reproductive performance of rat strains by increasing the pregnancy rate and the litter size
Superovulation with an anti-inhibin monoclonal antibody improves the reproductive performance of rat strains by increasing the pregnancy rate and the litter size Open
The rat is a multiparous rodent that has long been used in biomedical research, but the low reproductive performance in some rat strains hampers their broader use as research models. This study examined whether superovulation using an anti…
View article: Development of a new device for manipulating frozen mouse 2-cell embryos on the International Space Station
Development of a new device for manipulating frozen mouse 2-cell embryos on the International Space Station Open
Whether mammalian embryos develop normally under microgravity remains to be determined. However, embryos are too small to be handled by inexperienced astronauts who orbit Earth on the International Space Station (ISS). Here we describe the…
View article: Subgroup analysis of Japanese patients in a phase III randomized, controlled study of neoadjuvant atezolizumab or placebo, combined with <i>nab</i>-paclitaxel and anthracycline-based chemotherapy in early triple-negative breast cancer (IMpassion031)
Subgroup analysis of Japanese patients in a phase III randomized, controlled study of neoadjuvant atezolizumab or placebo, combined with <i>nab</i>-paclitaxel and anthracycline-based chemotherapy in early triple-negative breast cancer (IMpassion031) Open
Background In the global phase III IMpassion031 study, neoadjuvant atezolizumab plus nab-paclitaxel/anthracycline-based chemotherapy improved pathological complete response in patients with early stage triple-negative breast cancer. Here, …
View article: Development of a new device for manipulating frozen mouse 2-cell embryos on the International Space Station
Development of a new device for manipulating frozen mouse 2-cell embryos on the International Space Station Open
Whether mammalian embryos develop normally under microgravity remains to be determined. However, embryos are too small to be handled by inexperienced astronauts who orbit Earth on the International Space Station (ISS). Here we describe the…
View article: Use of anti-inhibin monoclonal antibody for increasing the litter size of mouse strains and its application to <i>in vivo</i>-genome editing technology
Use of anti-inhibin monoclonal antibody for increasing the litter size of mouse strains and its application to <i>in vivo</i>-genome editing technology Open
The litter size of mouse strains is determined by the number of oocytes naturally ovulated. Many attempts have been made to increase litter sizes by conventional superovulation regimens (e.g., using equine or human gonadotropins, eCG/hCG b…
View article: Highly rigid H3.1/H3.2–H3K9me3 domains set a barrier for cell fate reprogramming in trophoblast stem cells
Highly rigid H3.1/H3.2–H3K9me3 domains set a barrier for cell fate reprogramming in trophoblast stem cells Open
The placenta is a highly evolved, specialized organ in mammals. It differs from other organs in that it functions only for fetal maintenance during gestation. Therefore, there must be intrinsic mechanisms that guarantee its unique function…
View article: Mouse <i>in vivo</i>-derived late 2-cell embryos have higher developmental competence after high osmolality vitrification and −80°C preservation than IVF or ICSI embryos
Mouse <i>in vivo</i>-derived late 2-cell embryos have higher developmental competence after high osmolality vitrification and −80°C preservation than IVF or ICSI embryos Open
Mammalian embryos are most commonly cryopreserved in liquid nitrogen; however, liquid nitrogen is not available in special environments, such as the International Space Station (ISS), and vitrified embryos must be stored at -80°C. Recently…
View article: Easy and quick (EQ) sperm freezing method for urgent preservation of mouse strains
Easy and quick (EQ) sperm freezing method for urgent preservation of mouse strains Open
Cryopreservation of mouse spermatozoa is widely used for the efficient preservation and safe transport of valuable mouse strains. However, the current cryopreservation method requires special containers (plastic straws), undefined chemical…
View article: Loss of H3K27me3 imprinting in the Sfmbt2 miRNA cluster causes enlargement of cloned mouse placentas
Loss of H3K27me3 imprinting in the Sfmbt2 miRNA cluster causes enlargement of cloned mouse placentas Open
View article: Acrosin is essential for sperm penetration through the zona pellucida in hamsters
Acrosin is essential for sperm penetration through the zona pellucida in hamsters Open
Significance Mammalian oocytes are surrounded by the zona pellucida, a glycoprotein coat that protects the oocyte and embryo from mechanical damage during their preimplantation development within the oviduct. Fertilizing spermatozoa must p…
View article: Corrigendum to: Subgroup analysis of Japanese patients in a Phase 3 study of atezolizumab in advanced triple-negative breast cancer (IMpassion130)
Corrigendum to: Subgroup analysis of Japanese patients in a Phase 3 study of atezolizumab in advanced triple-negative breast cancer (IMpassion130) Open
View article: Subgroup analysis of Japanese patients in a Phase 3 study of atezolizumab in advanced triple-negative breast cancer (IMpassion130)
Subgroup analysis of Japanese patients in a Phase 3 study of atezolizumab in advanced triple-negative breast cancer (IMpassion130) Open
Background In the randomised Phase 3 IMpassion130 trial, atezolizumab combined with nab-paclitaxel (atezo + nab-P) in 902 patients with triple-negative breast cancer (TNBC) showed prolonged progression-free survival (PFS) in both the inten…
View article: Early production of offspring by <i>in vitro</i> fertilization using first-wave spermatozoa from prepubertal male mice
Early production of offspring by <i>in vitro</i> fertilization using first-wave spermatozoa from prepubertal male mice Open
Mature male mice (aged 10–12 weeks or older) are conventionally used for in vitro fertilization (IVF) in order to achieve high fertilization rates (e.g., > 70%). Here, we sought to determine the earliest age at which male mice (C57BL/6J st…
View article: Role of P2X3 receptors in scratching behavior in mouse models
Role of P2X3 receptors in scratching behavior in mouse models Open
View article: Telomere shortening by transgenerational transmission of TNF-α-induced TERRA via ATF7
Telomere shortening by transgenerational transmission of TNF-α-induced TERRA via ATF7 Open
Various stresses increase disease susceptibility and accelerate aging, and increasing evidence suggests that these effects can be transmitted over generation. Epidemiological studies suggest that stressors experienced by parents affect the…
View article: Identification of quantitative trait loci associated with the susceptibility of mouse spermatozoa to cryopreservation
Identification of quantitative trait loci associated with the susceptibility of mouse spermatozoa to cryopreservation Open
Although it is known that the susceptibility of mouse spermatozoa to freezing-thawing varies greatly with genetic background, the underlying mechanisms remain to be elucidated. In this study, to map genetic regions responsible for the susc…
View article: The Rodent-Specific MicroRNA Cluster within the Sfmbt2 Gene Is Imprinted and Essential for Placental Development
The Rodent-Specific MicroRNA Cluster within the Sfmbt2 Gene Is Imprinted and Essential for Placental Development Open
View article: CRISPR/Cas9-mediated genome editing in wild-derived mice: generation of tamed wild-derived strains by mutation of the a (nonagouti) gene
CRISPR/Cas9-mediated genome editing in wild-derived mice: generation of tamed wild-derived strains by mutation of the a (nonagouti) gene Open
Wild-derived mice have contributed to experimental mouse genetics by virtue of their genetic diversity, which may help increase the chance of identifying novel modifier genes responsible for specific phenotypes and diseases. However, gene …
View article: Efficient and scheduled production of pseudopregnant female mice for embryo transfer by estrous cycle synchronization
Efficient and scheduled production of pseudopregnant female mice for embryo transfer by estrous cycle synchronization Open
In embryo transfer experiments in mice, pseudopregnant females as recipients are prepared by sterile mating with vasectomized males. Because only females at the proestrus stage accept males, such females are selected from a stock of animal…
View article: Demineralization of cortical bone for improvement of Charpy impact fracture characteristics
Demineralization of cortical bone for improvement of Charpy impact fracture characteristics Open
Bone tissue is a composite structure of apatite particles distributed in collagen fibril matrix on a nano-size scale. Mechanical properties of cortical bone are determined by the apatite-collagen composition. The amount and specific orient…
View article: Effect of local demineralization treatments on fracture characteristics of cortical bone
Effect of local demineralization treatments on fracture characteristics of cortical bone Open