Publications by authors named "Ryosuke Takegawa"

Purine nucleotide adenosine triphosphate (ATP) is a source of intracellular energy maintained by mitochondrial oxidative phosphorylation. However, when released from ischemic cells into the extracellular space, they act as death-signaling molecules (eATP). Despite there being potential benefit in using pyruvate to enhance mitochondria by inducing a highly oxidative metabolic state, its association with eATP levels is still poorly understood.

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This prospective observational single-center cohort study aimed to determine an association between cerebrovascular autoregulation (CVAR) and outcomes in hypoxic-ischemic brain injury post-cardiac arrest (CA), and assessed 100 consecutive post-CA patients in Japan between June 2017 and May 2020 who experienced a return of spontaneous circulation. Continuous monitoring was performed for 96 h to determine CVAR presence. A moving Pearson correlation coefficient was calculated from the mean arterial pressure and cerebral regional oxygen saturation.

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Background: Cardiac arrest (CA) can lead to neuronal degeneration and death through various pathways, including oxidative, inflammatory, and metabolic stress. However, current neuroprotective drug therapies will typically target only one of these pathways, and most single drug attempts to correct the multiple dysregulated metabolic pathways elicited following cardiac arrest have failed to demonstrate clear benefit. Many scientists have opined on the need for novel, multidimensional approaches to the multiple metabolic disturbances after cardiac arrest.

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Cardiac arrest (CA) and concomitant post-CA syndrome lead to a lethal condition characterized by systemic ischemia-reperfusion injury. Oxygen (O ) supply during cardiopulmonary resuscitation (CPR) is the key to success in resuscitation, but sustained hyperoxia can produce toxic effects post CA. However, only few studies have investigated the optimal duration and dosage of O administration.

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Article Synopsis
  • Mitochondrial transplantation (MTx) could help improve recovery after heart issues caused by lack of oxygen.
  • The researchers studied how these donated mitochondria work in lab tests with cells and also on rats that had heart problems.
  • Results showed that fresh mitochondria helped the rats survive much better than those that were frozen, suggesting that using fresh mitochondria could be a good treatment option.
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Cardiac arrest (CA) patients suffer from systemic ischemia-reperfusion (IR) injury leading to multiple organ failure; however, few studies have focused on tissue-specific pathophysiological responses to IR-induced oxidative stress. Herein, we investigated biological and physiological parameters of the brain and heart, and we particularly focused on the lung dysfunction that has not been well studied to date. We aimed to understand tissue-specific susceptibility to oxidative stress and tested how oxygen concentrations in the post-resuscitation setting would affect outcomes.

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We previously developed a risk assessment tool to predict outcomes after heat-related illness (J-ERATO score), which consists of six binary prehospital vital signs. We aimed to evaluate the ability of the score to predict clinical outcomes for hospitalized patients with heat-related illnesses. In a nationwide, prospective, observational study, adult patients hospitalized for heat-related illnesses were registered.

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Background: No direct approach assessing pulmonary vascular permeability exists in the current therapeutic strategy for patients with acute respiratory distress syndrome (ARDS). Transpulmonary thermodilution measures hemodynamic parameters such as pulmonary vascular permeability index and extravascular lung water, enabling clinicians to assess ARDS severity. The aim of this study is to explore a precise transpulmonary thermodilution-based criteria for quantifying the severity of lung injury using a clinically relevant septic-ARDS pig model.

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This case study describes a 45-year-old Caucasian male with a past medical history of obesity, hypertension, and non-insulin-dependent diabetes mellitus, who in the setting of coronavirus disease 2019 (COVID-19) pneumonia, developed portal vein thrombosis (PVT) presenting as an acute abdomen after hospital discharge from a cholecystitis episode. PVT is a very infrequent thromboembolic condition, classically occurring in patients with systemic conditions such as cirrhosis, malignancy, pancreatitis, diverticulitis, autoimmunity, and thrombophilia. PVT can cause serious complications, such as intestinal infarction, or even death, if not promptly treated.

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Aim: Hyperglycemia is a common response to acute illness, but it is not often seen in critical conditions. The frequency and cause of hypoglycemia in septic patients have not been well elucidated. In this study, we focused on sepsis-associated hypoglycemia in the early phase and evaluated the impact of hypoglycemia on mortality.

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Clinical studies have demonstrated that dynamic changes in regional cerebral oxygen saturation (rSO) after cardiac arrest (CA) and cardiopulmonary resuscitation (CPR) have a role in predicting neurological outcomes after the return of spontaneous circulation (ROSC). Our study evaluated whether the timing of rSO decline shortly after CPR reflects the severity of brain injury in a rat model of CA. Rats were subjected to different durations of asphyxia to produce variable severities of brain injury, due to CA.

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Objective: Cardiac arrest (CA) is a major health burden with brain damage being a significant contributor to mortality. We found lysophosphatidylcholine (LPC), including a species containing docosahexaenoic acid (LPC-DHA), was significantly decreased in plasma post-CA, supplementation of which significantly improved neurological outcomes. The aim of this study is to understand the protective role of LPC-DHA supplementation on the brain post-CA.

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Background: The hemoglobin index (HbI) represents the amount of hemoglobin, which reflects the regional tissue blood volume. The HbI is calculated by a regional oxygen saturation monitor. In freshwater drowning, inhaled water is immediately absorbed into the blood causing hemodilution.

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Article Synopsis
  • - The study investigates the potential benefits of hydrogen gas (H) in conjunction with extracorporeal cardiopulmonary resuscitation (ECPR) for improving survival and brain function after cardiac arrest (CA) in rats, amid known complications of ECPR such as oxidative stress and inflammation.
  • - In a controlled experiment, rats that underwent asphyxial CA and were then resuscitated with ECPR showed significantly higher survival rates at 4 hours when treated with H gas compared to a placebo, with 77.8% survival in the H group versus 22.2% in the placebo group.
  • - Further results indicated that H-treated rats exhibited EEG recovery, improved brain oxygenation, and reduced markers
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Background: Despite much evidence supporting the monitoring of the divergence of transcutaneous partial pressure of carbon dioxide (tcPCO) from arterial partial pressure carbon dioxide (artPCO) as an indicator of the shock status, data are limited on the relationships of the gradient between tcPCO and artPCO (tc-artPCO) with the systemic oxygen metabolism and hemodynamic parameters. Our study aimed to test the hypothesis that tc-artPCO can detect inadequate tissue perfusion during hemorrhagic shock and resuscitation.

Methods: This prospective animal study was performed using female pigs at a university-based experimental laboratory.

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Background: The proportion of adult patients with return of spontaneous circulation (ROSC) following out-of-hospital cardiac arrest (OHCA) remains unchanged since 2012. A better resuscitation strategy is needed. This study evaluated the effectiveness of a regional cerebral oxygen saturation (rSO)-guided resuscitation protocol without rhythm check based on our previous study.

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We describe the clinical course of a 65-year-old male patient who suffered from hydrocarbon-induced myelodysplasia and was successfully treated with the thrombopoietin receptor agonist (TPO-RA), romiplostim. Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis, cytopenias, and increased risk of leukemic transformation. Here, we present a clinical vignette of MDS-associated thrombocytopenia refractory to first-line drugs as well as the TPO-RA, eltrombopag.

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The regional oxygen saturation (rSO₂) values of brain and muscle tissues can be measured simultaneously even if blood pressure cannot be measured due to circulatory failure associated with shock and may continuously reflect the oxygen supply-demand balance.

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Objectives: Cardiac arrest and subsequent resuscitation have been shown to deplete plasma phospholipids. This depletion of phospholipids in circulating plasma may contribute to organ damage postresuscitation. Our aim was to identify the diminishment of essential phospholipids in postresuscitation plasma and develop a novel therapeutic approach of supplementing these depleted phospholipids that are required to prevent organ dysfunction postcardiac arrest, which may lead to improved survival.

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This case series reviews four critically ill patients infected with severe acute respiratory syndrome coronavirus 2 (SARSCoV2) [coronavirus disease 2019 (COVID-19)] suffering from pneumatosis intestinalis (PI) during their hospital admission. All patients received the biological agent tocilizumab (TCZ), an interleukin (IL)-6 antagonist, as an experimental treatment for COVID-19 before developing PI. COVID-19 and TCZ have been independently linked to PI risk, yet the cause of this relationship is unknown and under speculation.

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Background: At lower ambient temperature, patients with out-of-hospital cardiac arrest (OHCA) easily experience hypothermia. Hypothermia has shown to improve the rate of successful return of spontaneous circulation (ROSC) in animal models. We hypothesized that lower temperature affects the impact of bystander cardiopulmonary resuscitation (CPR) on the increased odds of a favorable neurological outcome post-OHCA.

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Organ transplantation can be associated with vascular torsions and angulations of both recipient and donor vessels. Such kinks and/or torsions of vessels can compromise the vascular integrity, obstruct inflow and/or outflow, and result in loss of the organ and/or body parts. On many occasions, mild angulations and torsions can be successfully addressed by repositioning the organ.

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Background: Mitochondria are essential organelles that provide energy for cellular functions, participate in cellular signaling and growth, and facilitate cell death. Based on their multifactorial roles, mitochondria are also critical in the progression of critical illnesses. Transplantation of mitochondria has been reported as a potential promising approach to treat critical illnesses, particularly ischemia reperfusion injury (IRI).

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Despite recent advances in the management of post-cardiac arrest syndrome (PCAS), the survival rate, without neurologic sequelae after resuscitation, remains very low. Whole-body ischemia, followed by reperfusion after cardiac arrest (CA), contributes to PCAS, for which established pharmaceutical interventions are still lacking. It has been shown that a number of different processes can ultimately lead to neuronal injury and cell death in the pathology of PCAS, including vasoconstriction, protein modification, impaired mitochondrial respiration, cell death signaling, inflammation, and excessive oxidative stress.

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We compared the outcome of COVID-19 in immunosuppressed solid organ transplant (SOT) patients to a transplant naïve population. In total, 10 356 adult hospital admissions for COVID-19 from March 1, 2020 to April 27, 2020 were analyzed. Data were collected on demographics, baseline clinical conditions, medications, immunosuppression, and COVID-19 course.

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