Neurodevelopmental outcome of infants with birth asphyxia treated with magnesium sulfate

BACKGROUND: A neuroprotective effect of MgSO(4) has been shown in some animal models of perinatal hypoxic-ischemic brain damage. The aim of the present paper was to determine whether postnatal MgSO(4) infusion (250 mg/kg per day i.v. for 3 days, in combination with dopamine) is safe in infants with severe birth asphyxia, and also observe effects on neurodevelopmental outcome at 18 months. METHODS: Inclusion criteria were clinical history consistent with perinatal asphyxia; gestational age at least 37 weeks; 5 min Apgar score < or =6; failure to initiate spontaneous respiration within 10 min after birth; and symptoms of encephalopathy. On each day MgSO(4) was infused over 1 h in combination with dopamine (5 microg/kg per min). Changes in vital signs, clinical course of encephalopathy, laboratory variables, and adverse events were monitored. Infants were followed for 18 months. RESULTS: Thirty infants were studied. Mean birthweight was 2878 g; mean gestational age, 39.6 weeks, and median 5 min Apgar score, 3. All required endotracheal intubation for resuscitation. Median age at MgSO(4) initiation was 5 h. All infants had moderate or severe hypoxic-ischemic encephalopathy. Mean serum Mg(2+) concentration remained at least 1.3 mmol/L. MgSO(4) caused no change in physiological variables including mean arterial pressure. Two infants died as neonates, while six of 28 survivors had severe neurodevelopmental disability at 18 months; the remaining 22 had no neurodevelopmental disability. CONCLUSION: Postnatal infusion of MgSO(4) with dopamine caused no change in physiological variables. Deaths and severe sequelae were less frequent than in reported cases with the same grade of hypoxic-ischemic encephalopathy severity, and this treatment may improve neurodevelopmental outcome in infants with severe birth asphyxia.     

Electroporation in a Model of Cardiac Defibrillation

INTRODUCTION: It is known that high-strength shock disrupts the lipid matrix of the myocardial cell membrane and forms reversible aqueous pores across the membrane. This process is known as "electroporation." However, it remains unclear whether electroporation contributes to the mechanism of ventricular defibrillation. The aim of this computer simulation study was to examine the possible role of electroporation in the success of defibrillation shock. METHODS AND RESULTS: Using a modified Luo-Rudy-1 model, we simulated two-dimensional myocardial tissue with a homogeneous bidomain nature and unequal anisotropy ratios. Spiral waves were induced by the S1-S2 method. Next, monophasic defibrillation shocks were delivered externally via two line electrodes. For nonelectroporating tissue, termination of ongoing fibrillation succeeded; however, new spiral waves were initiated, even with high-strength shock (24 V/cm). For electroporating tissue, high-strength shock (24 V/cm) was sufficient to extinguish ongoing fibrillation and did not initiate any new spiral waves. Weak shock (16 to 20 V/cm) also extinguished ongoing fibrillation; however, in contrast to the high-strength shock, new spiral waves were initiated. Success in defibrillation depended on the occurrence of electroporation-mediated anodal-break excitation from the physical anode and the virtual anode. Some excitation wavefronts following electrical shock used a deexcited area with recovered excitability as a pass-through point; therefore, electroporation-mediated anodal-break excitation is necessary to block out the pass-through point, resulting in successful defibrillation. CONCLUSION: The electroporation-mediated anodal-break excitation mechanism may play an important role in electrical defibrillation.     

Relationship among work–treatment balance,job stress,and work engagement in Japan: a cross-sectional study

There is a drive to support workers in Japan undergoing medical treatment who wish to continue working, known as the work–treatment balance. This support for the work–treatment balance is expected to boost their mental health. This study examines the relationship among the work–treatment balance, job stress, and work engagement. This study was conducted in December 2020 in Japan, with 27,036 participants. We divided the participants into three groups by the receipt state of support for work–treatment balance: control group (do not need support), unsupported group, and supported group. The scores on the parameters of the job content questionnaire and the Utrecht Work Engagement Scale (UWES-3) were compared among groups using a multilevel regression with age-sex or multivariate-adjusted models. In the two models, the job control score of the unsupported group was significantly lower than that of the control group. The two social support scores of the supported group were significantly higher than those of the control group. The scores on the UWES-3 of the unsupported group were significantly lower than those of the control group. The support of work–treatment balance for workers could have a positive impact on their mental health.