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Background In Japan, approximately 20–25% of young women are underweight, highlighting a significant social issue with considerable future health risks. This generation is strongly influenced by the internalization of thin ideals, leading to a belief that being thin equates to beauty and a misconception that it equates to health. Recent studies have revealed that young women with insufficient physical activity and low dietary intake exhibit metabolic profiles similar to those of obese individuals, putting them at increased risk for developing diabetes in the future. Addressing these issues requires a multifaceted approach, with stable exercise habits crucial for enhancing body satisfaction by reducing the internalization of thin ideals and improving self-esteem. Given this context, it is essential to investigate the effects of exercise habits, particularly in underweight women. Therefore, this study investigates how exercise habits influence body satisfaction by mediating thin-ideal internalization and self-esteem, comparing these effects between underweight and normal-range weight women. Methods The study surveyed 400 young women aged 18–29 who are underweight and 189 with normal-range weight across Japan, assessing their exercise habits based on the Ministry of Health, Labour and Welfare’s National Health and Nutrition Survey criteria (exercising at least twice a week for over a year, with sessions lasting ≥ 30 min), subjective body satisfaction, sociocultural attitudes toward appearance, and self-esteem. Data analysis was conducted using the PROCESS macro for SPSS, which allowed for mediation analyses to test indirect effects. Thin-ideal internalization and self-esteem were analyzed as mediators of the relationship between exercise habits and body satisfaction. Mediation analyses were performed separately for underweight and normal-range weight groups to identify differences in the mechanisms underlying these relationships. Results Approximately 50% of participants in both groups reported regular exercise (average 2.5 days/week). In the underweight group, exercise habits fully mediated the relationship between reduced thin-ideal internalization, increased self-esteem, and improved body satisfaction. In the normal-range weight group, exercise habits reduced thin-ideal internalization and improved body satisfaction but had no significant effect on self-esteem. Conclusions The results highlight that the pathways through which exercise habits affect body satisfaction differ according to body mass index. For underweight women, reducing thin-ideal internalization and enhancing self-esteem through exercise habits is crucial. In contrast, interventions directly boosting self-esteem may be more effective for women with normal-range weight. These findings clarify the distinct roles of exercise habits in influencing body satisfaction for underweight and normal-range weight women in Japan.

Regeneration in many animals involves the formation of a blastema, which differentiates and organizes into the appropriate missing body parts. Although the mechanisms underlying blastema formation are often fundamental to regeneration biology, information on the cellular and molecular basis of blastema formation remains limited. Here, we focus on a fragmenting potworm ( Enchytraeus japonensis ), which can regenerate its whole body from small fragments. We find soxC and mmpReg as upregulated genes in the blastema. RNAi of soxC and mmpReg reduce the number of blastema cells, indicating that soxC and mmpReg promote blastema formation. Expression analyses show that soxC -expressing cells appear to gradually accumulate in blastema and constitute a large part of the blastema. Additionally, similar expression dynamics of SoxC orthologue genes in frog ( Xenopus laevis ) are found in the regeneration blastema of tadpole tail. Our findings provide insights into the cellular and molecular mechanisms underlying blastema formation across species. Blastema formation is a critical early step during regeneration, but how it is initially formed is still unclear. Here, they find soxC and mmpReg promote blastema formation in fragmenting potworms, and identify similar expression dynamics in tadpole tail, suggesting a conserved mechanism.

Fear is an adaptive emotion that elicits defensive behavioural responses against aversive threats in animals. In mammals, serotonin receptors (5-HTRs) have been shown to modulate fear-related neural circuits in the basolateral amygdala complex (BLA). To understand the phylogenetic continuity of the neural basis for fear, it is important to identify the neural circuit that processes fear in other animals. In birds, fear-related behaviours were suggested to be processed in the arcopallium/amygdala complex and modulated by the serotonin (5-HT) system. However, details about the distribution of 5-HTRs in the avian brain are very sparsely reported, and the 5-HTR that is potentially involved in fear-related behaviour has not been elucidated. In this study, we showed that orthologs of mammalian 5-HTR genes that are expressed in the BLA, namely 5-HTR1A , 5-HTR1B , 5-HTR2A , 5-HTR2C , 5-HTR3A , and 5-HTR4, are expressed in a part of the chick arcopallium/amygdala complex called the dorsal arcopallium. This suggests that serotonergic regulation in the dorsal arcopallium may play an important role in regulating fear-related behaviour in birds. Our findings can be used as a basis for comparing the processing of fear and its serotonergic modulation in the mammalian amygdala complex and avian arcopallium/amygdala complex.

The angiopoietin (ANGPT)–TIE2/TEK signaling pathway is essential for blood and lymphatic vascular homeostasis. ANGPT1 is a potent TIE2 activator, whereas ANGPT2 functions as a context-dependent agonist/antagonist. In disease, ANGPT2-mediated inhibition of TIE2 in blood vessels is linked to vascular leak, inflammation, and metastasis. Using conditional knockout studies in mice, we show TIE2 is predominantly activated by ANGPT1 in the cardiovascular system and by ANGPT2 in the lymphatic vasculature. Mechanisms underlying opposing actions of ANGPT2 in blood vs. lymphatic endothelium are poorly understood. Here we show the endothelial-specific phosphatase VEPTP (vascular endothelial protein tyrosine phosphatase) determines TIE2 response to ANGPT2. VEPTP is absent from lymphatic endothelium in mouse in vivo, permitting ANGPT2/TIE2-mediated lymphangiogenesis. Inhibition of VEPTP converts ANGPT2 into a potent TIE2 activator in blood endothelium. Our data support a model whereby VEPTP functions as a rheostat to modulate ANGPT2 ligand effect on TIE2.

This paper aims to explore the coordination among China's various maritime actors in the South China Sea (SCS). Since around 2009, China has reinforced its maritime territorial claims in the SCS and has taken coercive measures, including harassing other countries' vessels and using administrative tools to expand its effective control over disputed islands. One important question is whether China's tactics are based on a well-coordinated plan or are the unintended consequence of competition and self-interest among the various agencies. This paper shows that, firstly, organisational coordination between these agencies is improving, secondly, that the PLA has a salient role in the operation, and lastly, that the long-term trend is important. The paper implies that long-term aspirations are coalescing into more concrete plans under the strong leadership of Xi Jinping.

Animal personalities are stable, context-dependent behavioral differences. Associations between the personality of birds and polymorphisms in the dopamine receptor D4 (DRD4) gene have been repeatedly observed. In mammals, our understanding of the role of the dopamine (DA) system in higher cognitive functions and psychiatric disorders is improving, and we are beginning to understand the relationship between the neural circuits modulating the DA system and personality traits. However, to understand the phylogenetic continuity of the neural basis of personality, it is necessary to clarify the neural circuits that process personality in other animals and compare them with those in mammals. In birds, the DA system is anatomically and molecularly similar to that in mammals; however, the function of DRD4 remains largely unknown. In this study, we used chicks as model birds to reveal the expression regions of the DA neuron-related markers tyrosine hydroxylase (TH), dopa decarboxylase (DDC), dopamine β -hydroxylase (DBH) , and DRD4 , as well as other DRDs throughout the forebrain. We found that DRD4 was selectively expressed in the mitral cells of the olfactory bulb (OB). Furthermore, a detailed comparison of the expression regions of DA neurons and DRD4 in the OB revealed a cellular composition similar to that of mammals. Our findings suggest that the animal personality gene DRD4 is important for olfactory information processing in birds, providing a new basis for comparing candidate neural circuits for personality traits between birds and mammals.

Serotonin (5-hydroxytryptamine, 5-HT) is a phylogenetically conserved neurotransmitter and modulator. Neurons utilizing serotonin have been identified in the central nervous systems of all vertebrates. In the central serotonergic system of vertebrate species examined so far, serotonergic neurons have been confirmed to exist in clusters in the brainstem. Although many serotonin-regulated cognitive, behavioral, and emotional functions have been elucidated in mammals, equivalents remain poorly understood in non-mammalian vertebrates. The purpose of this review is to summarize current knowledge of the anatomical organization and molecular features of the avian central serotonergic system. In addition, selected key functions of serotonin are briefly reviewed. Gene association studies between serotonergic system related genes and behaviors in birds have elucidated that the serotonergic system is involved in the regulation of behavior in birds similar to that observed in mammals. The widespread distribution of serotonergic modulation in the central nervous system and the evolutionary conservation of the serotonergic system provide a strong foundation for understanding and comparing the evolutionary continuity of neural circuits controlling corresponding brain functions within vertebrates. The main focus of this review is the chicken brain, with this type of poultry used as a model bird. The chicken is widely used not only as a model for answering questions in developmental biology and as a model for agriculturally useful breeding, but also in research relating to cognitive, behavioral, and emotional processes. In addition to a wealth of prior research on the projection relationships of avian brain regions, detailed subdivision similarities between avian and mammalian brains have recently been identified. Therefore, identifying the neural circuits modulated by the serotonergic system in avian brains may provide an interesting opportunity for detailed comparative studies of the function of serotonergic systems in mammals.

The avian pallium is organised into clusters of neurons and does not have layered structures such as those seen in the mammalian neocortex. The evolutionary relationship between sub-regions of avian pallium and layers of mammalian neocortex remains unclear. One hypothesis, based on the similarities in neural connections of the motor output neurons that project to sub-pallial targets, proposed the cell-type homology between brainstem projection neurons in neocortex layers 5 or 6 (L5/6) and those in the avian arcopallium. Recent studies have suggested that gene expression patterns are associated with neural connection patterns, which supports the cell-type homology hypothesis. However, a limited number of genes were used in these studies. Here, we showed that chick orthologues of mammalian L5/6-specific genes, nuclear receptor subfamily 4 group A member 2 and connective tissue growth factor , were strongly expressed in the arcopallium. However, other chick orthologues of L5/6-specific genes were primarily expressed in regions other than the arcopallium. Our results do not fully support the cell-type homology hypothesis. This suggests that the cell types of brainstem projection neurons are not conserved between the avian arcopallium and the mammalian neocortex L5/6. Our findings may help understand the evolution of pallium between birds and mammals.

Background Rectal neuroendocrine carcinomas (NECs) are rare and associated with poorer prognoses compared to conventional adenocarcinomas. The efficacy of adjuvant chemotherapy for resectable rectal NECs remains uncertain. Herein, we present a case of rectal NEC successfully treated with postoperative chemotherapy using irinotecan plus cisplatin. Case presentation A 48-year-old woman with a history of endometrial cancer presented with an intramural rectal tumour detected on follow-up imaging. Colonoscopy revealed a 30 mm submucosal tumour, and laparoscopic low anterior resection was performed. Histopathological examination showed poorly differentiated atypical cells with solid growth patterns. Metastasis from the uterine cancer was ruled out due to histological differences between the primary uterine tumour and the rectal lesion, as well as the absence of hormone receptor immunohistochemical expression. Further immunohistochemical analysis revealed diffuse CD56 positivity, a high mitotic rate (> 20/10 high power fields) and a Ki-67 labelling index exceeding 70%. Based on these findings, a diagnosis of rectal NEC, T3N0M0, Stage IIB (UICC 8th edition), was established. Given the aggressive nature of the tumour evidenced by a high Ki-67 labelling index, adjuvant chemotherapy comprising six cycles of irinotecan plus cisplatin was administered to mitigate the risk of recurrence. At the 3-year follow-up, the patient was free of disease recurrence. Conclusion This case highlights the importance of multidisciplinary surgical interventions followed by adjuvant chemotherapy in managing rectal NECs.

Thyroid hormones are closely linked to the hatching process in precocial birds. Previously, we showed that thyroid hormones in brain had a strong impact on filial imprinting, an early learning behavior in newly hatched chicks; brain 3,5,3'-triiodothyronine (T3) peaks around hatching and imprinting training induces additional T3 release, thus, extending the sensitive period for imprinting and enabling subsequent other learning. On the other hand, blood thyroid hormone levels have been reported to increase gradually after hatching in altricial species, but it remains unknown how the brain thyroid hormone levels change during post-hatching development of altricial birds. Here, we determined the changes in serum and brain thyroid hormone levels of a passerine songbird species, the zebra finch using radioimmunoassay. In the serum, we found a gradual increase in thyroid hormone levels during post-hatching development, as well as differences between male and female finches. In the brain, there was clear surge in the hormone levels during development in males and females coinciding with the time of fledging, but the onset of the surge of thyroxine (T4) in males preceded that of females, whereas the onset of the surge of T3 in males succeeded that of females. These findings provide a basis for understanding the functions of thyroid hormones during early development and learning in altricial birds.