Publications by authors named "Hitoshi Ozawa"

Kisspeptin and galanin-like peptide (GALP) neurons in the hypothalamic arcuate nucleus (ARC) are involved in gonadotropin-releasing hormone (GnRH) neuron-mediated pulsatile luteinizing hormone (LH) secretion. Zucker fatty (ZF) rats display a leptin receptor gene abnormality and suppressed pulsatile LH secretion. ZF rats reportedly exhibit low hypothalamic GALP and kisspeptin expression, and GALP administration induces LH release in ZF rats.

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Diabetes mellitus disturbs kisspeptin-neurokinin B-dynorphin A (KNDy) neurons in the arcuate nucleus (ARC), which regulate pulsatile luteinizing hormone (LH) secretion in both sexes. However, it remains unclear whether a sex-specific association with the negative effects of diabetes on KNDy neurons exists. Therefore, we examined mRNA expression in KNDy neurons of diabetic male and female rats 7 weeks after streptozotocin (STZ) injection using histochemistry.

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Introduction: Lactotroph pituitary neuroendocrine tumors (PitNETs) are common pituitary tumors, but their underlying molecular mechanisms remain unclear. This study aimed to investigate the transcriptomic landscape of lactotroph PitNETs and identify potential molecular mechanisms and therapeutic targets through RNA sequencing and ingenuity pathway analysis (IPA).

Methods: Lactotroph PitNET tissues from five surgical cases without dopamine agonist treatment underwent RNA sequencing.

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Article Synopsis
  • The text refers to a correction made to a previously published article.
  • The article has a DOI (Digital Object Identifier) of 10.3389/fimmu.2023.1251784, which allows for easy access and citation of the work.
  • This correction is important for ensuring the accuracy and integrity of the published research.
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Macrophages are essential for the proper inflammatory and reparative processes that lead to regeneration of skeletal muscle after injury. Recent studies have demonstrated close links between the function of activated macrophages and their cellular metabolism. Sterol regulatory element-binding protein 1 (SREBP1) is a key regulator of lipid metabolism and has been shown to affect the activated states of macrophages.

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Mammalian ovulation is induced by a luteinizing hormone surge, which is triggered by elevated plasma estrogen levels; however, chronic exposure to high levels of estradiol is known to inhibit luteinizing hormone secretion. In the present study, we hypothesized that the inhibition of the luteinizing hormone surge by chronic estradiol exposure is due to the downregulation of the estrogen receptor alpha in kisspeptin neurons at hypothalamic anteroventral periventricular nucleus, which is known as the gonadotropin-releasing hormone/luteinizing hormone surge generator. Animals exposed to estradiol for 2 days showed an luteinizing hormone surge, whereas those exposed for 14 days showed a significant suppression of luteinizing hormone.

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Estrogen receptor α (ERα) regulates several physiological functions. In pathophysiological conditions, ERα is involved in the development and progression of estrogen-sensitive tumors. The ERα gene contains multiple 5'-untranslated exons and eight conventional coding exons and presents multiple isoforms generated by alternative promoter usage and alternative splicing.

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Neuropeptide B (NPB) has been identified as an endogenous peptide ligand for the orphan receptor NPBWR1. However, the effect of NPB on the central regulatory mechanisms of reproductive functions remains unclear. Our findings indicated the presence of Npb, Npw (which is another ligand for NPBWR1), and Npbwr1 mRNA in the hypothalamus of male and female rats at each stage of the estrous cycle.

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hybridization (ISH), which visualizes nucleic acids in tissues and cells, is a powerful tool in histology and pathology. Over 50 years since its invention, multiple attempts have been made to increase the sensitivity and simplicity of these methods. Therefore, several highly sensitive hybridization methods have been developed that offer researchers a wide range of options.

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Kisspeptin-neurokinin B-dynorphin A (KNDy) neurons in the arcuate nucleus (ARC) regulate pulsatile luteinizing hormone (LH) secretion. These neurons express estrogen receptors and are negatively regulated by estrogen. This study aimed to determine whether estrogen supplementation after short-term ovariectomy-induced estrogen depletion has different effects on KNDy neurons depending on the timing of the supplementation.

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The nutritional environment during development periods induces metabolic programming, leading to metabolic disorders and detrimental influences on human reproductive health. This study aimed to determine the long-term adverse effect of intrauterine malnutrition on the reproductive center kisspeptin-neurokinin B-dynorphin A (KNDy) neurons in the hypothalamic arcuate nucleus (ARC) of female offspring. Twelve pregnant rats were divided into ad-lib-fed (control, n = 6) and 50% undernutrition (UN, n = 6) groups.

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Article Synopsis
  • The research addresses challenges in studying ESR2 proteins due to limited detection systems, and introduces a new monoclonal antibody (PPZ0506) that works for both human and rodent ESR2 proteins.* -
  • This study builds on previous work by optimizing immunohistochemical detection methods specifically for mouse ESR2 proteins in paraffin-embedded ovary sections, focusing on critical factors such as heat-induced antigen retrieval and antibody dilution.* -
  • Findings reveal a more localized distribution of mouse ESR2 proteins compared to previous assumptions and highlight interspecies differences when comparing to human and rat ESR2 expression, which could clarify conflicting evidence in the field.*
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  • Antioxidant peptides, especially dipeptides, are gaining attention for their ability to neutralize free radicals and their unique nutritional benefits, despite their different physiological roles compared to regular amino acids.
  • The review discusses the structural properties, antioxidant activities, and biological effects of these dipeptides, aiming to enhance knowledge on their potential health benefits.
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  • In the late 2010s, AI technology started helping with food science and nutrition research.
  • The review looks at how AI is used in other areas like engineering and medicine, and also its history with food science.
  • It discusses current AI uses in agriculture and food, like finding healthy foods, checking diets, analyzing gut bacteria, and predicting toxic ingredients, and suggests these uses will be important in the future.
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The suprachiasmatic nucleus (SCN) of the hypothalamus is a nucleus that regulates circadian rhythms through the cyclic expression of clock genes. It has been suggested that circadian-rhythm-related, adverse postoperative events, including sleep disturbances and delirium, are partly caused by anesthesia-induced disruption of clock-gene expression. We examined the effects of multiple general anesthetics on the expression cycle of Period2 (Per2), one of the clock genes that regulate circadian rhythms in the SCN, and on the behavioral rhythms of animals.

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  • General anesthetics like sevoflurane and propofol have varying effects and side effects due to their different mechanisms of action, but comparative studies are still lacking.
  • This study involved anesthetizing rats with either sevoflurane or propofol to examine changes in brain activity and gene expression in specific brain regions.
  • The results showed distinct gene expression alterations between the two anesthetics, which could help in understanding their effects and potential side effects, such as postoperative nausea and agitation.
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Kisspeptin neurons, i.e. KNDy neurons, in the arcuate nucleus (ARC) coexpress neurokinin B and dynorphin and regulate gonadotropin-releasing hormone/luteinizing hormone (LH) pulses.

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Background: Regulation of the reproductive system has been explained by the actions and feedback of gonadotropin releasing hormone-luteinizing hormone/follicle stimulating hormone (GnRH-LH/FSH) -sex steroids; however, the discovery of kisspeptin neurons and a kisspeptin-GnRH-LH/FSH axis has prompted this regulation to be reviewed.

Methods: We investigated changes in kisspeptin neurons and associated changes in the hypothalamic-pituitary-gonadal (HPG) axis under various situations and experimental conditions using histochemical methods.

Main Findings Results: Kisspeptin neurons play an important role in receiving and integrating information from internal and external environmental factors and communicating it to the conventional HPG axis.

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Background: The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) is undertaking a major revision of ICH E6 Good Clinical Practice (GCP) decided to involve external stakeholders in ICH-GCP renovation. Activities such as surveys and public conferences have taken place in the United States, European Union, and Japan. For stakeholder engagement in Japan, a designated research group conducted a survey of academic stakeholders.

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Article Synopsis
  • Population aging is leading to a rise in elderly individuals and increasing costs for social security, necessitating a focus on both physical and cognitive care for this demographic.
  • The review explores the relationship between cognitive decline in the elderly and dietary patterns, highlighting the potential of various food components (like lipids, vitamins, and amino acids) to positively impact cognitive function.
  • The aim is to inspire the creation of new foods and technologies that could enhance cognitive health and extend the healthy lifespan of aging individuals.
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Cesarean section (C/S) is one way of delivering babies, and is chosen when mothers or babies are facing problems or life-threatening conditions during pregnancy. Many meta-analyses have suggested an etiological relationship between C/S delivery and autism spectrum disorders (ASDs). However, as a risk factor for ASDs, C/S delivery has not yet been well studied.

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Metabolic stress resulting from either lack or excess of nutrients often causes infertility in both sexes. Kisspeptin-neurokinin B-dynorphin A (KNDy) neurons in the arcuate nucleus (ARC) has been suggested to be a key players in reproduction via direct stimulation of the pulsatile gonadotropin-releasing hormone (GnRH) and subsequent gonadotropin release in mammalian species. In this study, we investigated the effect of high-fat diet (HFD) on hypothalamic KNDy gene expression to examine the pathogenic mechanism underlying obesity-induced infertility in male and female rats.

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