The susceptibility to ventricular arrhythmias under the conditions of cardiac ischemia and reperfusion was investigated in the Langendorff heart preparation of rats fed for eight weeks a standard chow enriched with 2% of pulverized wild garlic leaves. The isolated hearts were perfused with a modified Krebs-Henseleit solution. The incidence of ventricular fibrillation (VF) during 20 min occlusion of the descending branch of the left coronary artery (LAD) was significantly reduced in the wild garlic group as compared to untreated controls (20% vs 88%). The same holds for the size of the ischemic zone (33.6% vs 40.9% of heart weight). In the reperfusion experiments (5 min after 10 min ischemia), ventricular tachycardia (VT) occurred in 70% of the wild garlic group vs 100% in untreated controls and VF in 50% vs 90%. The time until occurrence of extrasystoles, VT or VR was prolonged. No significant alterations in cardiac fatty acid composition could be observed. Although the prostacyclin production was slightly increased in hearts of the wild garlic group, inhibition of cyclooxygenase by acetylsalicylic acid (ASA; aspirin) could not completely prevent the cardioprotective effects suggesting that the prostaglandin system does not play a decisive role in the cardioprotective action of wild garlic. Furthermore, a moderate angiotensin converting enzyme (ACE) inhibiting action of wild garlic was found in vitro as well as in vivo that could contribute to the cardioprotective and blood pressure lowering action of wild garlic. Whether a free radical scavenging activity of wild garlic is involved in its cardioprotective effects remains to be established.
Fat emulsions containing medium chain triglycerides (MCT) have recently been introduced into clinical practice as a component of total parenteral nutrition. Since several authors reported increased pulmonary artery pressure and impaired gas exchange during intravenous (i.v.) fat use, in particular in septic patients, we studied the pulmonary hemodynamic and gas exchange effects of i.v. fat containing MCT and long chain triglycerides (LCT) in patients with sepsis syndrome. As the effects of fat emulsions have been attributed to increased formation of prostanoids, the production of thromboxane A2 and prostacyclin was investigated by the determination of urinary thromboxane B2 and 6-keto-prostaglandin F2 alpha, respectively. The i.v. fat use did not induce any alterations in pulmonary hemodynamics and gas exchange, the distribution of ventilation and perfusion nor urinary prostaglandin content. We conclude that fat emulsions containing MCT induce little alterations in pulmonary hemodynamics and gas exchange. This result is probably due to reduced prostaglandin formation because fat emulsions containing MCT provide less prostaglandin precursors than pure LCT emulsions.
1. The effects of racemic (rac) ibuprofen and its S(+)‐ and R(−)− enantiomers on functions of human polymorphonuclear cells (PMN) and platelets were studied in vitro. 2. Rac‐ibuprofen inhibited PMN functions (O2‐ generation, beta‐glucuronidase release, LTB4 formation). Similar IC50 values (40‐100 microM) were obtained for the S(+)‐ and R(‐ )‐enantiomers. 3. All forms of ibuprofen inhibited cyclooxygenase‐ related platelet functions (aggregation, thromboxane formation). The S(+)‐enantiomer was about twice as active as the racemate while the R(‐ )‐enantiomer was at least 10‐fold less active. This demonstrates that the S(+) is the only cyclooxygenase inhibitory component of the racemate. 4. The concentrations of rac‐ibuprofen in PMN and platelets were similar to those in the incubation medium and represented equal concentrations of the enantiomers. This indicates that neither interconversion nor tissue accumulation of the compounds occurred. 5. These data indicate that antineutrophil effects of ibuprofen on human PMN are independent of cyclooxygenase inhibition. Therefore, R(−)− ibuprofen may be superior to the S(+)‐isomer for the treatment of PMN‐ dependent inflammatory diseases. However, effective free drug concentrations may not be obtained in vivo.
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