ABSTRACT
BACKGROUND: A link between venous thromboembolism (VTE) and air travel has been recently discussed, so the present study aimed to clarify the characteristics of acute pulmonary thromboembolism (PTE) associated with air travel in Japan. METHODS AND RESULTS: The study group comprised 36 patients with acute PTE associated with air travel. Patients' characteristics, clinical risk factors for VTE and coagulation abnormalities were investigated, and compared with a group of PTE not associated with travel. Of the 36 cases, 30 cases were female, 34 were over 40 years of age and all had flown more than 6 h. Two-thirds of all cases did not leave their seats during the flight. Of the patients, 44% had no clinical risk factors for VTE or coagulation abnormalities. Idiopathic PTE (ie, PTE without clinical risk factors or coagulation abnormalities) was significantly more common in the air travel group. CONCLUSION: Acute PTE associated with air travel in Japan is common in elderly women and may occur without any clinical risk factors for VTE or coagulation abnormalities. Remaining seated throughout the flight increases the risk.
Subject(s)
Aerospace Medicine , Pulmonary Embolism , Travel , Adult , Aerospace Medicine/methods , Age Factors , Aged , Aircraft , Female , Humans , Japan , Male , Middle Aged , Pulmonary Embolism/epidemiology , Pulmonary Embolism/etiology , Retrospective Studies , Risk Factors , Sex FactorsABSTRACT
The expression of inducible nitric oxide synthase (iNOS) and the resultant increased nitric oxide production are associated with endotoxemia and atherosclerotic lesions observed in transplant hearts or balloon-injured artery. Ursodeoxycholic acid has been shown to have cardiovascular protective effects, such as inhibition of the development of transplant arteriosclerosis, but its mechanism remains unclear. Here, we investigated the effects of ursodeoxycholic acid on nitric oxide production and the expression of iNOS in vascular smooth muscle cells isolated from adult rat aorta and rabbit coronary artery. Nitrite released from cells in the culture medium was measured with the Griess reaction. iNOS mRNA and protein were measured by Northern and Western blot analyses. Treatment with ursodeoxycholic acid (30-1000 microM) significantly inhibited lipopolysaccharide plus interferon-gamma-induced nitric oxide production in a concentration-dependent manner, but ursodeoxycholic acid showed only small inhibitory effects on nitric oxide production that had already been induced by lipopolysaccharide plus interferon-gamma. Ursodeoxycholic acid by itself did not affect basal nitric oxide production. Ursodeoxycholic acid also suppressed lipopolysaccharide plus interferon-gamma-induced expression of iNOS mRNA and protein. Ursodeoxycholic acid had the most potent inhibitory effect among various kinds of bile acids examined, i.e. chenodeoxycholic acid, deoxycholic acid, cholic acid and conjugated bile acids such as tauroursodeoxycholic acid. These results suggest that ursodeoxycholic acid inhibits the induction of iNOS and then nitric oxide production in aortic and coronary artery smooth muscle cells, suggesting a possible mechanism for the cardiovascular protective effect of ursodeoxycholic acid under various pathophysiological conditions such as endotoxemia and atherosclerosis.
Subject(s)
Muscle, Smooth, Vascular/drug effects , Nitric Oxide Synthase/metabolism , Ursodeoxycholic Acid/pharmacology , Animals , Blotting, Northern , Blotting, Western , Dose-Response Relationship, Drug , Gene Expression Regulation, Enzymologic/drug effects , Interferon-gamma/pharmacology , Lipopolysaccharides/pharmacology , Male , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/metabolism , Nitric Oxide/metabolism , Nitric Oxide Synthase/genetics , Nitric Oxide Synthase Type II , RNA, Messenger/drug effects , RNA, Messenger/genetics , RNA, Messenger/metabolism , Rabbits , Rats , Rats, Wistar , Time FactorsABSTRACT
BACKGROUND: The effects of lysophosphatidylcholine (LPC) on electrophysiological activities and intracellular Ca2+ concentration ([Ca2+]i) were investigated in coronary arterial smooth muscle cells (CASMCs). METHODS AND RESULTS: The patch clamp techniques and Ca2+ measurements were applied to cultured rabbit CASMCs. The membrane potential was -46.0+/-5.0 mV, and LPC depolarized it. Replacement of extracellular Na+ with NMDG+ hyperpolarized the membrane and antagonized the depolarizing effects of LPC. In Na+-, K+-, or Cs+-containing solution, the voltage-independent background current with reversal potential (E(r)) of approximately +0 mV was observed. Removal of Cl- failed to affect it. When extracellular cations were replaced by NMDG+, E(r) was shifted to negative potentials. La3+ and Gd3+ abolished the background current, but nicardipine and verapamil did not inhibit it. In Na+-containing solution, LPC induced a voltage-independent current with E(r) of approximately +0 mV concentration-dependently. Similar current was recorded in K+- and Cs+-containing solution. La3+ and Gd3+ inhibited LPC-induced current, but nicardipine and verapamil did not inhibit it. In cell-attached configurations, single-channel activities with single-channel conductance of approximately 32pS were observed when patch pipettes were filled with LPC. LPC increased [Ca2+]i as the result of Ca2+ influx, and La3+ completely antagonized it. CONCLUSIONS: These results suggest that (1) nonselective cation current (I(NSC)) contributes to form membrane potentials of CASMCs and (2) LPC activates I(NSC), resulting in an increase of [Ca2+]i. Thus, LPC may affect CASMC tone under various pathophysiological conditions such as ischemia.
