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Aim: To analyze characteristics and investigate prognostic indicators of out-of-hospital cardiac arrest (OHCA) in a hilly area in Japan. Methods: A retrospective population-based study was conducted using the Utstein Registry for 4280 OHCA patients in the Nagasaki Medical Region (NMR) registered over the 10-year period from 2011 to 2020. The main outcome measure was a favorable cerebral performance category (CPC 1-2). Sites at which OHCA occurred were classified into "sloped places (SPs)" (not easily accessible by emergency medical services [EMS] personnel due to slopes) and "accessible places (APs)" (EMS personnel could park an ambulance close to the site). The characteristics and prognosis based on CPC were compared between SPs and APs, and multivariable analysis was performed. Results: No significant improvement in prognosis occurred in the NMR from 2011 to 2020. Prognosis in SPs was significantly worse than that in APs. However, multivariable analysis did not identify SP as a prognostic indicator. The following factors were associated with survival and CPC 1-2: age group, witness status, first documented rhythm, bystander-initiated cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) use, use of mechanical CPR (m-CPR) device or esophageal obturator airway (EOA), and year. Both m-CPR and EOA use were associated with a poor prognosis. Conclusion: In a hilly area, OHCA patients in SPs had a worse prognosis than those in APs, but SPs was not significantly associated with prognosis by multivariable analysis. Interventions to increase bystander-initiated CPR and AED use could potentially improve outcomes of OHCA in the NMR.
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INTRODUCTION: Repulsive guidance molecule a (RGMa) is a key protein that negatively regulates neuronal regeneration as its inhibition enhances axonal growth and promotes functional recovery in animal models of spinal cord injury. However, the role of RGMa in traumatic brain injury (TBI) remains elusive. This study aimed to clarify TBI-responsive RGMa expression in a murine model. METHODS: Adult male C57BL/6J mice were subjected to controlled cortical impact. Brains were extracted 6 hours and 1, 3, 7, 14 and 21 days after injury (n = 6 in each group). Changes in the messenger RNA (mRNA) expression of RGMa and its receptor, neogenin, were evaluated by quantitative polymerase chain reaction in the damaged area of the cortex and contralateral cortex, along with expression measurement of inflammation-related molecules. Neurological deficit was also assessed by the cylinder test. RESULTS: Neurological score was consistently lower in the TBI group compared to the sham group throughout the experimental period. The mRNA expressions of representative inflammatory cytokine TNF-α and chemokine receptor CCR2 were remarkably increased in the injured cortex on day 1 and gradually decreased over time, although remaining at higher values at least until day 14. The mRNA expressions of RGMa and neogenin were significantly suppressed in the damaged cortex until day 3. Interestingly, RGMa expression was suppressed most on day 1 and recovered over time. CONCLUSION: In the acute phase of TBI, gene expression of inflammatory cytokines significantly increased, and gene expressions of RGMa and neogenin significantly decreased in the inflammatory milieu of the damaged area. Despite the subsequent remission of inflammation, RGMa gene expression recovered to the normal level 1 week after TBI. Intrinsic regenerative response to acute brain injury might be hampered by the following recovery of RGMa expression, hinting at the possibility of functional RGMa inhibition as a new, effective maneuver against TBI.