Publications by authors named "Katsumura T"

Article Synopsis
  • The review highlights advances in social neuroscience through the study of medaka fishes, focusing on their social cognition and mate choice behaviors, especially involving visual cues.
  • Medaka fishes are advantageous for research due to their rich genetic resources and ease of genetic manipulation, making them ideal for studying evolutionary social neuroscience.
  • The introduction of single-cell transcriptome technology, paired with 'Adaptive Circuitry Census,' promises to deepen understanding of molecular mechanisms behind visual mate preferences and mating strategies across species.
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Coprolites contain various kinds of ancient DNAs derived from gut micro-organisms, viruses, and foods, which can help to determine the gut environment of ancient peoples. Their genomic information should be helpful in elucidating the interaction between hosts and microbes for thousands of years, as well as characterizing the dietary behaviors of ancient people. We performed shotgun metagenomic sequencing on four coprolites excavated from the Torihama shell-mound site in the Japanese archipelago.

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  • - This study explored how the oxygen dynamics in the vastus lateralis (VL) muscle relates to systemic oxygen supply during high-intensity cycling in young men without an attenuation point (AP) in muscle deoxygenation.
  • - Participants underwent ramp cycling exercises before and after 8 weeks, while their muscle oxygen saturation and deoxygenated hemoglobin were monitored to assess changes in oxygen dynamics.
  • - Results indicated a significant increase in the slope of deoxygenated hemoglobin in VL post-training, suggesting that changes in systemic oxygen supply are more influential on muscle deoxygenation during intense exercise than oxygen balance in other thigh muscles.
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  • The study examines how lowlanders' bodies respond to hypobaric hypoxia (HH), simulating high-altitude conditions for 75 minutes in a controlled chamber.
  • Significant changes were observed: levels of aldosterone and cortisol decreased, while inflammatory markers like interleukin (IL)-6 and IL-8, along with white blood cell counts, increased after HH exposure.
  • The research indicates that even brief exposure to HH triggers notable endocrine and immune responses, especially in individuals with lower peripheral oxygen saturation (SpO), enhancing our understanding of physiological adaptations to low-oxygen environments.
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The aim of this study was to compare systemic and quadriceps muscle O dynamics between aerobic capacity-matched subjects without (NAP; n = 5) and with (CON; n = 13) attenuation point in deoxygenated haemoglobin concentration (deoxy-Hb) at vastus lateralis (AP) during ramp cycling exercise. Muscle O saturation (SmO) and deoxy-Hb were monitored at the vastus lateralis (VL), rectus femoris (RF), and vastus medialis (VM) by spatial resolved near infrared spectroscopy during exercise. Cardiac output (CO) and pulmonary O uptake (VO) were also continuously measured.

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Mating experience shapes male mating behavior across species, from insects, fish, and birds, to rodents. Here, we investigated the effect of multiple mating experiences on male mating behavior in "naïve" (defined as sexually inexperienced) male medaka fish. The latency to mate with the same female partner significantly decreased after the second encounter, whereas when the partner was changed, the latency to mate was not decreased.

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Background: Numerous protocols exist to counteract prolonged seizures during modified electroconvulsive therapy (mECT), such as anaesthetic adjustments and ventilation. Evidence on methods for deciding whether to continue with the next round of mECT after a prolonged seizure and to prevent recurrent seizures is currently not well established.

Case Presentation: The patient was a 76-year-old woman with major depressive disorder.

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Article Synopsis
  • The study compared muscle oxygen dynamics during exercise across three age groups: elderly (73 years), middle-aged (50 years), and young adults (25 years), all performing ramp bicycle exercises to exhaustion.
  • Results showed that elderly participants had lower muscle oxygen saturation and oxygenated hemoglobin levels compared to the other groups, while deoxygenated and total hemoglobin levels were similar across all ages.
  • The findings suggest that muscle oxygen dynamics are relatively maintained in early aging stages but decline in later stages, likely due to reduced oxygen delivery, and different mechanisms affect peak oxygen uptake between age groups.
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Background Recent clinical trials have demonstrated the possible pleiotropic effects of SGLT2 (sodium-glucose cotransporter 2) inhibitors in clinical cardiovascular diseases. Atrial electrical and structural remodeling is important as an atrial fibrillation (AF) substrate. Methods and Results The present study assessed the effect of canagliflozin (CAN), an SGLT2 inhibitor, on atrial remodeling in a canine AF model.

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  • The study compared muscle oxygen dynamics during exercise between overweight (OW) and normal-weight (NW) women who had similar aerobic capacities.
  • Overweight women showed higher muscle oxygen saturation (SmO) and lower levels of deoxygenated hemoglobin and total hemoglobin changes compared to normal-weight women during graded treadmill exercise.
  • The findings indicate that despite matching pulmonary oxygen uptake, overweight adults had reduced muscle blood volume and oxygen extraction during exercise, which correlated with their peak aerobic capacity.
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Animal sex-determining genes, which bifurcate for female and male development, are diversified even among closely related species. Most of these genes emerged independently from various sex-related genes during species diversity as neofunctionalization-type genes. However, the common mechanisms of this divergent evolution remain poorly understood.

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Medaka is a model organism in medicine, genetics, developmental biology and population genetics. Lab stocks composed of more than 100 local wild populations are available for research in these fields. Thus, medaka represents a potentially excellent bioresource for screening disease-risk- and adaptation-related genes in genome-wide association studies.

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The aim of this study was to test the effects of aerobic cycling training on O dynamics in several leg muscles in early post-myocardial infarction (post-MI). Fifteen post-MI patients were divided into a 12-week training group (TR, n = 9) or a control/non-training group (CON, n = 6). All participants performed ramp bicycle exercise until exhaustion at two times: within 12-35 days of their MI and then again 12 weeks later.

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Lamin is an intermediate protein underlying the nuclear envelope and it plays a key role in maintaining the integrity of the nucleus. A defect in the processing of its precursor by a metalloprotease, ZMPSTE24, results in the accumulation of farnesylated prelamin in the nucleus and causes various diseases, including Hutchinson-Gilford progeria syndrome (HGPS). However, the role of lamin processing is unclear in fish species.

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Background: Many injuries of the lower extremities, especially the knee and ankle, occur during sports activity, and the incidence rate is higher in women than in men.

Hypothesis: The hypothesis was that phases of the menstrual cycle affect the width of the tibiofibular syndesmosis during drop landing in healthy young women and that such changes at the tibiofibular joint also affect the dynamics and neuromuscular coordination of the lower extremities.

Study Design: Descriptive laboratory study.

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Humans have spread out all over the world adapting to many different cold environments. Recent worldwide genome analyses and animal experiments have reported dozens of genes associated with cold adaptation. The uncoupling protein 1 (UCP1) gene enhances thermogenesis reaction in a physiological process by blocking ATP (adenosine triphosphate) synthesis on a mitochondrial membrane in brown adipose tissues.

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The aim of this study was to compare the muscle oxygen dynamics between early post-myocardial infarction (n = 12; MI) and age-matched elderly subjects without MI (n = 12; CON) in several leg muscles during ramp cycling exercise. Muscle oxygen saturation (SmO), deoxygenated-hemoglobin concentration (∆deoxy-Hb), and total-hemoglobin concentration (∆total-Hb) were monitored continuously at the distal site of vastus lateralis (VLd), proximal site of the vastus lateralis (VLp), rectus femoris (RF), vastus medialis (VM), gastrocnemius medialis (GM), and tibialis anterior (TA) muscles by near infrared spatial resolved spectroscopy. At given absolute workloads, higher SmO was observed at VLd, VLp, RF, and VM in MI, compared to CON.

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Humans show various responses to the environmental stimulus in individual levels as "physiological variations." However, it has been unclear if these are caused by genetic variations. In this study, we examined the association between the physiological variation of response to light-stimulus and genetic polymorphisms.

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Nbs1 is one of the genes responsible for Nijmegen breakage syndrome, which is marked with high radiosensitivity. In human NBS1 (hNBS1), Q185E polymorphism is known as the factor to cancer risks, although its DSB repair defect has not been addressed. Here we investigated the genetic variations in medaka (Oryzias latipes) wild populations, and found 40 nonsynonymous single nucleotide polymorphisms (SNPs) in medaka nbs1 (olnbs1) gene within 5 inbred strains.

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Background: The circadian clock is set up around a 24-h period in humans who are awake in the daytime and sleep in the nighttime, accompanied with physiological and metabolic rhythms. Most haplorhine primates, including humans, are diurnal, while most "primitive" strepsirrhine primates are nocturnal, suggesting primates have evolved from nocturnal to diurnal habits. The mechanisms of physiological changes causing the habits and of genetic changes causing the physiological changes are, however, unknown.

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Muscle tissue oxygenation is a critical issue in muscle complications such as pain, exhaustion, stiffness, or fatigue during and after exercise. The aim of this study was to investigate whether the changes of muscle tissue oxygenation could be observed at both erector spinae muscle at S1 level and gastrocnemius during and after acupuncture stimulation to ipsilateral erector spinae at S1 level. The subjects were ten healthy males.

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Article Synopsis
  • This study compared muscle oxygen dynamics during exercise between elderly patients with angina pectoris (AP) and matched controls.
  • AP patients showed higher muscle oxygen saturation (SmO2) and lower deoxygenated hemoglobin concentrations (∆deoxy-Hb) during exercise compared to the control group.
  • There was a negative correlation between changes in SmO2 and peak oxygen uptake (VO2), indicating that AP patients have a blunted muscle deoxygenation response which may be linked to their reduced aerobic capacity.
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  • The study aimed to understand how muscle deoxygenation changes over time with endurance training in untrained males.
  • Nine male participants underwent a cycling exercise protocol to evaluate their peak oxygen uptake (VO2peak) and muscle oxygen saturation before and after 3 and 6 weeks of endurance training.
  • Results showed that VO2peak significantly improved after both training periods, while muscle oxygen saturation (SmO2) decreased after training but remained consistent between the two training phases, indicating increased muscle oxygen availability contributes to VO2peak improvements mainly in the first 3 weeks.
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