Excitatory and inhibibitory reflexogenic skin areas for the intercostal respiratory neurons in the dog

1. Effects of various kinds of adequate stimuli such as touching, pinching, heating and cooling to various skin areas as well as repetitive electrical stimulations to a nerve branch innervating the skin areas upon the unitary discharges of the expiratory or the inspiratory muscle units of the intercostal muscles were studied on the spinal dogs. Effects of pinching upon the intercostal nerve action potentials elicited in reflex by single electrical shock to the adjacent intercostal nerve were also studied. 2. Excitatory skin area for the expiratory discharges roughly exhibits a triangle, one of whose vertex faces the sternum, the side against the vertex corresponds to the apical line of the spine and includes the spot from where the discharges of a muscle unit are led off. The triangular area is surrounded by a belt-shaped zone having no reflex response. All the other wide area is the inhibitory one. 3. Both the excitatory and the inhibitory skin areas for the discharges of the inspiratory muscle unit are exceedingly narrow in contrast to those for the expiratory discharge, having a tendency to be limited to the small localized area involving the spot from where the discharges are led off. In the other extensive area, however, any reflex effect is not provoked. 4. The more intense and noxious the adequate stimuli become, the more prominent the effect come to be. 5. When the repetitive electrical stimuli to the skin nerve innervating the excitatory area are weak in intensity or low in frequency, an increasing discharge of the respiratory muscle unit results, whereas when the stimuli are sufficiently raised in either of the two factors above described, a remarkable inhibition preceded by a momentary acceleration ensues. In the case of stimulation of the skin nerve innervating the inhibitory area, however, the inhibition alone is obtained throughout. 6. Reflex action potentials in the intercostal nerve elicited by single shock stimuli to the adjacent intercostal nerve show a shortening of latency and an increase in size by pinching the excitatory skin area, while the reverse effects to those above described are obtained by pinching the inhibitory one.</p

Automatic activies of the spinal cord concerned with the respiratory movements

1. After spinal transection at the medulla-spinal junction the thoracic respiratory movements no longer appear in the adult animals, nevertheless the sporadic spike discharges can be recorded from the intercostal muscles. 2. Both in the acute and chronic experiments the spinal cord is transected at the two levels of Th7 and Thl1 respectively and all the dorsal rootlets coming into that part of the cord lying between the transections are severed. The sporadic spike discharges with irregular intervals varying about 0.5 to 3.0 sec. can be recorded from intercostal muscles in the 8th to 10th segments of the spinal cord isolated. There can never be found any reflex influence of the skin stimulation upon the discharges, which also disappear provided the intercostal nerves innervating the muscles are severed. 3. From these results it may be concluded that the spinal cord is endowed with an ability to initiate the impulses autochthonously to excite the intercostal muscles, even though it is only poorly developed in the adult animals.</p

Evaluation of the Appropriate Root Pressure for Maintaining Heartbeat during an Aortic Cross-clamp for Primary Repair of the Aortic Arch in Premature Infants with Associated Cardiac Anomalies

We developed a new cardiopulmonary bypass (CPB) method to minimize myocardial damage during aortic arch reconstruction. In this method, coronary flow and heartbeat were stabilized by maintaining the aortic root pressure with an adjusted preload of the ventricle during aortic cross-clamping. This study was performed to determine the appropriate root pressure to maintain the heartbeat without causing deterioration of ventricular function. Study 1. Under partial CPB, the ascending aorta was cross-clamped in 6 pigs (group 1). Experimental data at various systolic aortic root pressures was analysed to determine the appropriate root pressure. Study 2. In group 2 (control, n＝6), the aorta was not clamped, while in group 3 (n＝6), the aorta was cross-clamped for 60 min and the systolic aortic root pressure was maintained at the pressure determined in study 1. Study 1. The diastolic coronary flow was stabilized at values comparable to that before initiation of CPB (6.6±1.4ml/beat) when the systolic aortic root pressure was above 80mmHg. Intracardiac pressure and the myocardial oxygen consumption (MvO2) seemed to be acceptable when the systolic aortic root pressure was below 100mmHg. Therefore, 90mmHg was selected for study 2. Study 2. Perioperative cardiac function did not differ between the groups. We concluded that 90mmHg was the systolic aortic root pressure appropriate for this method

Efficacy of MCI-186, a free-radical scavenger and antioxidant, for resuscitation of nonbeating donor hearts

ObjectiveOxygen-derived free radicals are responsible in part for reperfusion injury in globally ischemic myocardium. In this study, the efficacy for resuscitation of nonbeating donor hearts of MCI-186, a free-radical scavenger and antioxidant, was investigated in a pig transplantation model.MethodsCardiac arrest was induced by asphyxiation. After 30 minutes of global ischemia, the hearts were excised and immediately reperfused from the aortic root with normoxemic blood cardioplegia (Po2 100 mm Hg) for 20 minutes, followed by perfusion with hyperoxemic blood (Po2 300 mm Hg). MCI-186 (3 mg/kg) was administered into the aortic root for the first 30 minutes of reperfusion in the treated group (n = 6), and untreated hearts were used as a control group (n = 6). Transplantation was performed with the heart beating.ResultsPosttransplantation recovery of cardiac output, end-systolic pressure–volume ratio, and first derivative of pressure of the left ventricle in the treated group were significantly better than those in the control group. The coronary sinus–aortic root difference in malondialdehyde levels remained low throughout reperfusion in the treated group but abruptly increased after initiation of oxygenated blood perfusion in the control group. The MCI-186–treated hearts showed low degree of edema and well-preserved ultrastructure with normal-appearing organelles, whereas the untreated hearts had marked swelling of mitochondria and scant glycogen granules.ConclusionMCI-186 exerts a cardioprotective action at least partly by inhibition of lipid peroxidation. Antioxidant therapy at the initial reperfusion is essential to successful resuscitation of nonbeating hearts by continuous myocardial perfusion

Mitochondrial fission in hepatocytes as a potential therapeutic target for nonalcoholic steatohepatitis

[Aim] The mitochondria are highly plastic and dynamic organelles; mitochondrial dysfunction has been reported to play causative roles in diabetes, cardiovascular diseases, and nonalcoholic fatty liver disease (NAFLD). However, the relationship between mitochondrial fission and NAFLD pathogenesis remains unknown. We aimed to investigate whether alterations in mitochondrial fission could play a role in the progression of NAFLD. [Methods] Mice were fed a standard diet or choline-deficient, L-amino acid-defined (CDAA) diet with vehicle or mitochondrial division inhibitor-1. [Results] Substantial enhancement of mitochondrial fission in hepatocytes was triggered by 4 weeks of feeding and was associated with changes reflecting the early stage of human nonalcoholic steatohepatitis (NASH), steatotic change with liver inflammation, and hepatocyte ballooning. Excessive mitochondrial fission inhibition in hepatocytes and lipid metabolism dysregulation in adipose tissue attenuated liver inflammation and fibrogenesis but not steatosis and the systemic pathological changes in the early and chronic fibrotic NASH stages (4- and 12-week CDAA feeding). These beneficial changes due to the suppression of mitochondrial fission against the liver and systemic injuries were associated with decreased autophagic responses and endoplasmic reticulum stress in hepatocytes. Injuries to other liver cells, such as endothelial cells, Kupffer cells, and hepatic stellate cells, were also attenuated by the inhibition of mitochondrial fission in hepatocytes. [Conclusions] Taken together, these findings suggest that excessive mitochondrial fission in hepatocytes could play a causative role in NAFLD progression by liver inflammation and fibrogenesis through altered cell cross-talk. This study provides a potential therapeutic target for NAFLD

Impact of Energetic Ion Driven Global Modes on Toroidal Plasma Confinements

Excitation of energetic-ion-driven Alfv6n eigenmodes (AEs) and their impact on energetic ion confinement are widely and intensively studied in helical devices such as CHS and LHD as well as major tokamaks. The excitation of AEs sensitively depends on the parameter space defined by the averaged beam beta and the velocity ratio V6nlV6 (V611 : injected beam ion velocity, Va: Alfv6n velocity). In LHD, these two relevant parameters are widely scanned without suffering from current disruptions. So far, toroidicity induced AE (TAE), global AE (GAE) and energetic particle mode (EPM) or resonant TAE (R-TAE) were identified during tangential neutral beam injection (NBI) in CHS and LHD. Moreover, a new coherent mode with the frequency by about 8 times higher than the TAE frequency was observed in NBI heated plasmas of LHD at low magnetic field (<0.6T). This mode may be induced by helical field components of the confinement field. Nonlinear phenomena of bursting amplitude modulation and fast frequency chirping are clearly seen for TAEs and EPMs in CHS and LHD. EPMs in CHS and bursting TAEs in LHD enhance radial transport of energetic ions in certain plasma conditions

X-ray study of ferroic octupole order producing anomalous Hall effect

放射光でついに見えた磁気オクタポール --熱を電気に変える新たな担い手--. 京都大学プレスリリース. 2021-09-27.Recently found anomalous Hall, Nernst, magnetooptical Kerr, and spin Hall effects in the antiferromagnets Mn₃X (X = Sn, Ge) are attracting much attention for spintronics and energy harvesting. Since these materials are antiferromagnets, the origin of these functionalities is expected to be different from that of conventional ferromagnets. Here, we report the observation of ferroic order of magnetic octupole in Mn₃Sn by X-ray magnetic circular dichroism, which is only predicted theoretically so far. The observed signals are clearly decoupled with the behaviors of uniform magnetization, indicating that the present X-ray magnetic circular dichroism is not arising from the conventional magnetization. We have found that the appearance of this anomalous signal coincides with the time reversal symmetry broken cluster magnetic octupole order. Our study demonstrates that the exotic material functionalities are closely related to the multipole order, which can produce unconventional cross correlation functionalities

High Baseline Lipoprotein(a) Level as a Risk Factor for Coronary Artery Calcification Progression: Sub-analysis of a Prospective Multicenter Trial

Lipoprotein(a), or Lp(a), is a low-density lipoprotein-like particle largely independent of known risk factors for, and predictive of, cardiovascular disease (CVD). We investigated the association between baseline Lp(a) levels and the progression of coronary artery calcification (CAC) in patients with hypercholesterolemia undergoing statin therapy. This study was a sub-analysis of a multicenter prospective study that evaluated the annual progression of CAC under intensive and standard pitavastatin treatment with or without eicosapentaenoic acid in patients with an Agatston score of 1 to 999, and hypercholesterolemia treated with statins. We classified the patients into 3 groups according to CAC progression. A total of 147 patients (mean age, 67 years; men, 54%) were analyzed. The proportion of patients with Lp(a) > 30 mg/dL significantly increased as CAC progressed (non-progression; 5.4%, 0100; 23.6%). Logistic regression analysis showed that Lp(a) > 30 mg/dL was an independent predictor of the annual change in Agatston score > 100 (OR: 5.51; 95% CI: 1.28-23.68; p=0.02), even after adjusting for age, sex, hypertension, diabetes mellitus, current smoking, body mass index, and lipid-lowering medications. Baseline Lp(a) >30 mg/dL was a predictor of CAC progression in this population of patients with hypercholesterolemia undergoing statin therapy