64 research outputs found

    Effects of Heavy Element Abundance on Evolution of Supernova Remnants

    Get PDF
    The evolution of supernova remnants is investigated numerically for the various abundances of the ambient medium in order to see the effects of a supernova explosion on the interstellar gas in various stages of the galactic evolution. It is shown that the time-evolution of a supernova remnant is delayed with the decrease in the heavy element abundance because of the suppressed cooling efficiency in the gas, and that the dynamical behavior of a remnant in the regime of z (the ratio of heavy element abundance to cosmic one) less than 10^ is essentially the same as that in the case of no heavy element. The heavy element cooling also affects properties of dense shell behind the shock front, and the kinetic energy and the radius of a remnant. A discussion is given that the pressure in the hot gas, produced by supernova explosions, could be sufficiently high to support against the gravitational contraction in the initial phase of the Galaxy

    N-methyl-D-aspartate receptors play important roles in acquisition and expression of the eyeblink conditioned response in glutamate receptor subunit delta2 mutant mice.

    Get PDF
    Classical eyeblink conditioning has been known to depend critically on the cerebellum. Apparently consistent with this, glutamate receptor subunit delta2 null mutant mice, which have serious morphological and functional deficiencies in the cerebellar cortex, are severely impaired in delay paradigm. However, these mutant mice successfully learn in trace paradigm, even in \u270-trace paradigm,\u27 in which the unconditioned stimulus starts just after the conditioned stimulus terminates. Our previous studies revealed that the hippocampus and the muscarinic acetylcholine receptors play crucial roles in 0-trace paradigm in glutamate receptor subunit delta2 null mutant mice unlike in wild-type mice, suggesting a large contribution of the forebrain to 0-trace conditioning in this type of mutant mice. In the present study, we investigated the role of N-methyl-D-aspartate receptors in 0-trace eyeblink conditioning in glutamate receptor subunit delta2 null mutant mice. Mice were injected intraperitoneally with the noncompetitive N-methyl-d-aspartate receptor antagonist (+)MK-801 (0.1mg/kg) or saline, and conditioned with 350-ms tone conditioned stimulus followed by 100-ms periorbital shock unconditioned stimulus. Glutamate receptor subunit delta2 null mutant mice that received (+)MK-801 injection exhibited a severe impairment in acquisition of the conditioned response, compared with the saline-injected glutamate receptor subunit delta2 null mutant mice. In contrast, wild-type mice were not impaired in acquisition of 0-trace conditioned response by (+)MK-801 injection. After the injection solution was changed from (+)MK-801 to saline, glutamate receptor subunit delta2 null mutant mice showed a rapid and partial recovery of performance of the conditioned response. On the other hand, when the injection solution was changed from saline to (+)MK-801, glutamate receptor subunit delta2 null mutant mice showed a marked impairment in expression of the pre-acquired conditioned response, whereas impairment of the expression was small in wild-type mice. Injection of (+)MK-801 had no significant effects on spontaneous eyeblink frequency or startle eyeblink frequency to the tone conditioned stimulus in either glutamate receptor subunit delta2 null mutant mice or wild-type mice. These results suggest that N-methyl-D-aspartate receptors play critical roles both in acquisition and expression of the conditioned response in 0-trace eyeblink conditioning in glutamate receptor subunit delta2 null mutant mice

    The hippocampus plays an important role in eyeblink conditioning with a short trace interval in glutamate receptor subunit delta 2 mutant mice.

    Get PDF
    Mutant mice lacking the glutamate receptor subunit delta2 exhibit changes in the structure and function of the cerebellar cortex. The most prominent functional feature is a deficiency in the long-term depression (LTD) at parallel fiber-Purkinje cell synapses. These mutant mice exhibit severe impairment during delay eyeblink conditioning but learn normally during trace eyeblink conditioning without the cerebellar LTD, even with a 0 trace interval. We investigated the hippocampal contribution to this cerebellar LTD-independent "0 trace interval" learning. The mutant mice whose dorsal hippocampi were aspirated exhibited severe impairment in learning, whereas those that received post-training hippocampal lesions retained the memory. The wild-type mice showed no impairment in either case. These results suggest that the hippocampal component of the eyeblink conditioning task becomes dominant when cerebellar LTD is impaired

    Three-year survival in primary cardiac angiosarcoma

    Get PDF
    A healthy 18-year-old girl was referred to our hospital for further evaluations of cardiac angiosarcoma. Transthoracic echocardiography showed an immobile 4.6 cm×3.7 cm cardiac mass. The mass was occupying right atrial chamber and partially, invading into annulus of tricuspid valve on transesophageal echocardiography. At surgery, the mass was seen to be protruding from right atrial appendage and adhering to right side of pericardium. The histological findings were consistent with cardiac angiosarcoma and immunological staining was positive for CD34 and CD31. Afterward, although she received radiochemotherapy, she died of metastasis of cardiac angiosarcoma more than three years after surgical resection

    Reduction mammaplasty and mastopexy for the contralateral breast after reconstruction surgery following cancer resection : A report of 3 cases

    Get PDF
    Background : Breast reconstruction generally involves autologous tissue transplantation and placement of a mammary prosthesis. When the patient’s breasts are extremely large and ptotic, breast reconstruction often results in significantly asymmetrical appearance. However, a good aesthetic outcome after reconstruction surgery following cancer resection is an important quality-of-life factor. We evaluated the efficacy of touch-up surgery, either reduction mammaplasty or mastopexy, performed on the contralateral breast for symmetrization. Methods : Reduction mammaplasty was performed on the contralateral breast in 2 patients and mastopexy was performed on the contralateral breast in 1 patient after reconstruction surgery following cancer resection, between 2008 and 2014. We reviewed each patient’s medical record for general clinical information and for the methods of breast cancer resection and breast reconstruction used, wait time between breast cancer resection and touch-up surgery, preservation of the sensitivity of the nipple-areola complex after the touch-up surgery, and aesthetic outcome (based on visual analog scale score). Results : Wait times in the 3 cases were 4, 9, and 18 months. Nipple-areolar sensitivity was well preserved in all 3 cases. Aesthetic outcomes were judged “excellent” or “very good.” Conclusion : Revision surgery on the contralateral breast 4 to 18 months after breast reconstruction substantially improves the aesthetic outcome

    Long-term treatment with hyperbaric air improves hyperlipidemia of db/db mice

    Get PDF
    Hyperbaric air (HBA) is used to improve healing of wounds including diabetic ulcer. The aim of this study was to clarify the effects of HBA exposure on lipid and glucose metabolism in db/db mice. HBA did not influence the weight of db/db mice. Serum levels of free fatty acid and triglyceride, but not glucose and insulin, were significantly decreased after 6 weeks of treatment with HBA. The mRNA expressions of CPT-1, PPARα and PGC-1α genes, which are related to lipid metabolism, were significantly up-regulated in the muscle and liver. Increases in TNFα and MCP1 mRNA, which impaired lipid metabolism, were also attenuated by HBA treatment. These results suggest that exposure of HBA could have beneficial effects on lipid metabolism in patients with type 2 diabetes mellitus

    Development of Skin Flaps for Reconstructive Surgery : Random Pattern Flap to Perforator Flap

    Get PDF
    Flap transplantation has been an important procedure in plastic and reconstructive surgery to cover and fill various defects. Flap necrosis due to blood circulation failure leads to severe complications, especially in a patient undergoing reconstruction concerning the body cavity after tumor ablation. Surgical procedures for flap transplantation have been further improved and developed. We have reviewed from the random pattern flap to the newest procedure, the perforator flap. Perforator vessels were investigated in the process of development of the fasciocutaneous flap and have become important for blood supply of the skin flap. Blood circulation of the flap has become more stable and reliable than ever with the development and findings of the perforator vessels. Further development of a skin flap will be based on the perforasome concept, which involves the study of the territory and linking of perforator vessels
    corecore