Hydrogen sulfide is produced endogenously by a variety of enzymes involved in cysteine metabolism. Clinical data indicate that endogenous levels of hydrogen sulfide are diminished in various forms of cardiovascular diseases. The aim of the current study was to investigate the effects of hydrogen sulfide supplementation on cardiac function during reperfusion in a clinically relevant experimental model of cardiopulmonary bypass. Twelve anesthetized dogs underwent hypothermic cardiopulmonary bypass. After 60 minutes of hypothermic cardiac arrest, reperfusion was started after application of either saline vehicle (control, n = 6), or the sodium sulfide infusion (1 mg/kg/hour, n = 6). Biventricular hemodynamic variables were measured by combined pressure-volume-conductance catheters. Coronary and pulmonary blood flow, vasodilator responses to acetylcholine and sodiumnitroprusside and pulmonary function were also determined. Administration of sodium sulfide led to a significantly better recovery of left and right ventricular systolic function (P < 0.05) after 60 minutes of reperfusion. Coronary blood flow was also significantly higher in the sodium sulfide-treated group (P < 0.05). Sodium sulfide treatment improved coronary blood flow, and preserved the acetylcholine-induced increases in coronary and pulmonary blood (P < 0.05). Myocardial ATP levels were markedly improved in the sulfide-treated group. Thus, supplementation of sulfide improves the recovery of myocardial and endothelial function and energetic status after hypothermic cardiac arrest during cardiopulmonary bypass. These beneficial effects occurred without any detectable adverse hemodynamic or cardiovascular effects of sulfide at the dose used in the current study. The aim of the current study was to test potential cytoprotective and anti-inflammatory effects of the novel biological mediator hydrogen sulfide in murine models. Murine J774 macrophages were grown in culture and exposed to cytotoxic concentrations of nitrosoglutathione, or peroxynitrite (a reactive species formed from the reaction of nitric oxide and superoxide). Pretreatment of the cells with sodium sulfide (60-300 µM) reduced the loss of cell viability elicited by the nitric oxide donor compound (3 mM) or by peroxynitrite (3 mM), as measured by the MTT method. Sodium sulfide did not affect cell viability in the concentration range tested. In mice subjected to bacterial lipopolysaccharide (LPS, 5 mg/kg i.p.), treatment of the animals with sodium sulfide (0.2 mg/kg/hour for 4 hours, administered in Alzet minipumps) reduced the LPSinduced increase in plasma IL-1β and TNFα levels. These responses were attenuated when animals were pretreated with the heme oxygenase inhibitor tin-protoporphyrin IX (6 mg/kg). The current results point to the cytoprotective and anti-inflammatory effects of hydrogen sulfide, in cells exposed to nitrosative stress, and in animals subjected to endotoxemia. Introduction It has been previously shown that the two forms of acute cholecystitis, acute acalculous cholecystiti...
For various (patho‐)physiological human study designs it would desirable to have a safe, noninvasive continuous blood pressure measurement for use under hyperbaric conditions. For this purpose we present the modifications to the Portapres™ system (Model 1) and its preliminary validation.The Portapres™ system was systematically analyzed according to “failure mode and effects analysis” principles. We identified possible failure modes related to pressure resistance and fire hazard in a hyperbaric and oxygen enriched environment, and adapted the device accordingly. 1) the carbon brush pump was replaced by a pressure reducing valve to be connected to a pressurized air supply. 2) gas‐filled electrolytic capacitors were replaced for solid equivalents. 3) the power supply was modified to fit the low voltage supply in the hyperbaric chamber.Preliminary validation of the modified system was performed in 5 healthy volunteers: against a standard Finapres® device (n=5) there was concurrence between measurements under normobaric conditions, with non‐significant (p > 0.2) mean differences of 1.03 and 4.93 mmHg in systolic and diastolic blood pressure. Hyperbaric measurements proceeded without problems in two of the healthy volunteers.The modified system seems to provide safe and reliable measurements both under normo‐ and hyperbaric conditions. Further validation is warranted.
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