Shen-Fu injection reduces impaired myocardial β-adrenergic receptor signaling after cardiopulmonary resuscitation / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Post-resuscitation myocardial dysfunction has been implicated as a major cause of fatal outcome in patients who survive initially successful cardiopulmonary resuscitation (CPR). In our previous study, we found that impaired myocardial β-adrenergic receptor (AR) signaling is a key mechanism in post-resuscitation myocardial dysfunction and Shen-Fu injection (SFI) can attenuate post-resuscitation myocardial dysfunction. However, whether SFI can prevent impaired post-resuscitation myocardial β-AR signaling is not yet known. In this study, we investigated the effect of SFI on impaired myocardial β-AR signaling occurring post-resuscitation in a porcine model of cardiac arrest.</p><p><b>METHODS</b>Ventricular fibrillation was induced electrically in anesthetized male landrace domestic pigs. After 4 minutes of untreated ventricular fibrillation, cardiopulmonary resuscitation was initiated. Sixteen successfully resuscitated pigs were randomized to receive a continuous infusion of either SFI (0.5 ml/min; n = 8) or saline (placebo; n = 8) for 6 hours, beginning 15 minutes after the return of spontaneous circulation (ROSC). Hemodynamic and echocardiographic data were recorded. β-AR signaling was assessed at 6 hours after the intervention by measuring myocardial adenylate cyclase activity, β-AR density and β-AR kinase expression.</p><p><b>RESULTS</b>Treatment with SFI produced better maximum rate of left ventricular pressure increase (dp/dt(max)) and maximum rate of left ventricular pressure decline (-dp/dt(max)), cardiac output, and ejection fraction after ROSC. SFI treatment was also associated with lower myocardial β-adrenergic receptor kinase expression, whereas basal and isoproterenol-stimulated adenylate cyclase activity and the total β-AR density were significantly increased in the SFI group when compared with the placebo group.</p><p><b>CONCLUSION</b>SFI attenuated post-resuscitation myocardial dysfunction by preventing impaired myocardial β-AR signaling after CPR.</p>

Evaluation of respiratory dysfunction in a pig model of severe acute dichlorvos poisoning / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Respiratory failure is the main cause of death in acute organophosphorus pesticide poisoning. In this study, a pulse-induced contour cardiac output monitor was used to evaluate the respiratory status in a pig model of acute dichlorvos poisoning.</p><p><b>METHODS</b>Twenty female pigs were randomly allocated to dichlorvos (n = 7), atropine (n = 7), and control (n = 6) groups. In the dichlorvos group, pigs were administered 80% emulsifiable dichlorvos (100 mg/kg) via a gastric tube. In the atropine group, pigs were similarly administered dichlorvos, and 0.5 hours later, atropine was injected to attain and maintain atropinization. The control group was administered saline solution. Arterial blood gas was measured at 0, 0.5, 1, 2, 4, and 6 hours post-injection. The extravascular lung water index and pulmonary vascular permeability index were recorded by the pulse-induced contour cardiac output monitor. At termination of the study, the animals were euthanized, the lung wet-to-dry weight ratio was determined, and histopathology was observed.</p><p><b>RESULTS</b>In the dichlorvos group, the extravascular lung water index and pulmonary vascular permeability index were substantially increased from 0.5 hours and were particularly high within 1 hour. In the atropine group, these indices increased initially, but decreased from the 1-hour mark. The control group exhibited no obvious changes. In both the dichlorvos and atropine groups, the extravascular lung water index was negatively correlated with partial pressure of oxygen/fraction of inspiration oxygen (PO2/FiO2) and positively correlated with the pulmonary vascular permeability index. Compared with the control group, the lung wet-to-dry weight ratio markedly increased and the histopathological findings obviously changed in the dichlorvos group, but only mildly increased and changed, respectively, in the atropine group.</p><p><b>CONCLUSION</b>The extravascular lung water index is an appropriate and valuable parameter for assessment of respiratory function in acute dichlorvos poisoning.</p>