82 research outputs found

    Radiative gravastar with thermal spectrum; Sudden vacuum condensation without gravitational collapse

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    The gravastar is an exotic compact object proposed as a final product of gravitational collapse of a massive object in order to resolve problems associated with black holes. It is enclosed by a thin crust and the inside of it is occupied by the positive cosmological constant. Recently, the present authors studied quantum particle creation through spherically symmetric gravitational collapse to form a gravastar, and showed that the newly formed gravastar emits thermal radiation with the Gibbons-Hawking temperature of its de Sitter core. In this paper, in order to understand more about the thermal radiation associated with the gravastar formation, we investigate the quantum particle creation in another toy model of the gravastar formation; a star with the hollow inside suddenly becomes a gravastar through gravitational vacuum condensation. We find that the thermal radiation is emitted from the gravastar just formed also in the present model. The thermal radiation from the gravastar just formed comes from the change of the geometry inside the star accompanied by gravitational vacuum condensate.Comment: 22 pages, 2 figures. arXiv admin note: text overlap with arXiv:2203.14519. Discussions about the temperature of the radiation are added in the revised versio

    Pluripotency of mesenchymal cells derived from synovial fluid in patients with temporomandibular joint disorder.

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    Mesenchymal stem cells are an interesting source of material for regenerative medicine. The present study aimed at characterizing the phenotype and differentiation potential of adherent synovial fluid-derived cells from temporomandibular joint (TMJ) disorder patients

    Circulatory C-type natriuretic peptide reduces mucopolysaccharidosis-associated craniofacial hypoplasia in vivo

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    Skeletal alterations in the head and neck region, such as midfacial hypoplasia, foramen magnum stenosis and spinal canal stenosis, are commonly observed in patients with mucopolysaccharidosis (MPS). However, enzyme replacement therapy (ERT), one of the major treatment approaches for MPS, shows limited efficacy for skeletal conditions. In this study, we analysed the craniofacial morphology of mice with MPS type VII, and investigated the underlying mechanisms promoting jaw deformities in these animals. Furthermore, we investigated the effects of C-type natriuretic peptide (CNP), a potent endochondral ossification promoter, on growth impairment of the craniofacial region in MPS VII mice when administered alone or in combination with ERT. MPS VII mice exhibited midfacial hypoplasia caused by impaired endochondral ossification, and histological analysis revealed increased number of swelling cells in the resting zone of the spheno-occipital synchondrosis (SOS), an important growth centre for craniomaxillofacial skeletogenesis. We crossed MPS VII mice with transgenic mice in which CNP was expressed in the liver under the control of the human serum amyloid-P component promoter, resulting in elevated levels of circulatory CNP. The maxillofacial morphological abnormalities associated with MPS VII were ameliorated by CNP expression, and further prevented by a combination of CNP and ERT. Histological analysis showed that ERT decreased the swelling cell number, and CNP treatment increased the width of the proliferative and hypertrophic zones of the SOS. Furthermore, the foramen magnum and spinal stenoses observed in MPS VII mice were significantly alleviated by CNP and ERT combination. These results demonstrate the therapeutic potential of CNP, which can be used to enhance ERT outcome for MPS VII-associated head and neck abnormalities

    Association Between Tooth Loss and Longitudinal Changes in B-Type Natriuretic Peptide Over 5 Years in Postmenopausal Women: The Nagahama Study

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    BACKGROUND: There is disparity between the sexes in cardiovascular diseases including heart failure (HF). This study aimed to investigate the effect of periodontal disease (PD) on plasma B-type natriuretic peptide (BNP) concentration across sex, age, and menopausal status, as well as the interaction effect of MT and diabetes mellitus (DM) on BNP. METHODS: This large-scale prospective cohort study enrolled 7, 539 individuals with no myocardial infarctions or angina pectoris at baseline from the general Japanese population. The association between baseline number of missing teeth (MT) and the longitudinal changes in BNP over 5 years (ΔBNP) was evaluated according to sex and menopausal status. RESULTS: Among 7, 539 participants, 3, 190 were postmenopausal women with a mean age ± standard deviation of 61.1 ± 7.6 at baseline. Multivariate analysis revealed a positive association between MT and ΔBNP among postmenopausal women even after adjusting for covariates, including traditional HF risk factors (coefficient, 0.210; 95% confidence interval [CI], 0.107 to 0.312; P 50. Including an interaction term (MT × DM) in the multivariate model revealed a positive interaction between MT and DM in ΔBNP among postmenopausal women (coefficient for interaction, 1.365; 95% CI, 0.902 to 1.827; P for interaction <0.001). CONCLUSIONS: Our study showed a positive association between MT and ΔBNP, as well as a positive effect of the interactive association between MT and DM, among postmenopausal women. Our results suggest a sex difference of an adverse effect of PD on initial myocardial wall stress in the ventricles

    Periodontal Tissue as a Biomaterial for Hard-Tissue Regeneration following bmp-2 Gene Transfer

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    The application of periodontal tissue in regenerative medicine has gained increasing interest since it has a high potential to induce hard-tissue regeneration, and is easy to handle and graft to other areas of the oral cavity or tissues. Additionally, bone morphogenetic protein-2 (BMP-2) has a high potential to induce the differentiation of mesenchymal stem cells into osteogenic cells. We previously developed a system for a gene transfer to the periodontal tissues in animal models. In this study, we aimed to reveal the potential and efficiency of periodontal tissue as a biomaterial for hard-tissue regeneration following a bmp-2 gene transfer. A non-viral expression vector carrying bmp-2 was injected into the palate of the periodontal tissues of Wistar rats, followed by electroporation. The periodontal tissues were analyzed through bone morphometric analyses, including mineral apposition rate (MAR) determination and collagen micro-arrangement, which is a bone quality parameter, before and after a gene transfer. The MAR was significantly higher 3–6 d after the gene transfer than that before the gene transfer. Collagen orientation was normally maintained even after the bmp-2 gene transfer, suggesting that the bmp-2 gene transfer has no adverse effects on bone quality. Our results suggest that periodontal tissue electroporated with bmp-2 could be a novel biomaterial candidate for hard-tissue regeneration therapy.Kawai M.Y., Ozasa R., Ishimoto T., et al. Periodontal Tissue as a Biomaterial for Hard-Tissue Regeneration following bmp-2 Gene Transfer. Materials, 15, 3, 993. https://doi.org/10.3390/ma15030993

    Emerging roles of ARHGAP33 in intracellular trafficking of TrkB and pathophysiology of neuropsychiatric disorders

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    Intracellular trafficking of receptor proteins is essential for neurons to detect various extracellular factors during the formation and refinement of neural circuits. However, the precise mechanisms underlying the trafficking of neurotrophin receptors to synapses remain elusive. Here, we demonstrate that a brain-enriched sorting nexin, ARHGAP33, is a new type of regulator for the intracellular trafficking of TrkB, a high-affinity receptor for brain-derived neurotrophic factor. ARHGAP33 knockout (KO) mice exhibit reduced expression of synaptic TrkB, impaired spine development and neuropsychiatric disorder-related behavioural abnormalities. These deficits are rescued by specific pharmacological enhancement of TrkB signalling in ARHGAP33 KO mice. Mechanistically, ARHGAP33 interacts with SORT1 to cooperatively regulate TrkB trafficking. Human ARHGAP33 is associated with brain phenotypes and reduced SORT1 expression is found in patients with schizophrenia. We propose that ARHGAP33/SORT1-mediated TrkB trafficking is essential for synapse development and that the dysfunction of this mechanism may be a new molecular pathology of neuropsychiatric disorders
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