Regulation of human internal mammary and radial artery contraction by extracellular and intracellular calcium channels and cyclic adenosine 3', 5' monophosphate.

Background: The internal mammary (IMA) and radial arteries (RA), which are routinely used in coronary artery bypass grafting, show a significant incidence of postoperative vasospasm. The present study evaluated the respective roles of calcium (Ca2+)-dependent and cyclic adenosine 3', 5' monophosphate-dependent (cAMP) signaling in mediating contraction and relaxation of the IMA and RA.

Methods: We examined the contractile responses of the IMA and RA to potassium chloride, a depolarizing agent; phenylephrine, an alpha-adrenergic agonist; and U46619, a thromboxane analogue, in the absence and presence (0.

Thromboxane receptor stimulation suppresses guanylate cyclase-mediated relaxation of radial arteries.

Background: The internal mammary artery (IMA) and the radial artery (RA) are routinely used in coronary artery bypass grafting. However, RA grafts have a higher incidence of postoperative vasospasm and comparatively poor patency rates. The present study was undertaken to investigate the signaling pathways mediating contraction and relaxation in the IMA and RA with the aim of better understanding the mechanism underlying the propensity of RA grafts to spasm.

Role of prostaglandins in mediating differences in human internal mammary and radial artery relaxation elicited by hypoxia.

The effects of hypoxia-reoxygenation on internal mammary (IMA) and radial (RA) arteries used for coronary artery bypass grafting (CABG) were examined to identify mechanisms regulating contractile function and differences that could contribute to vasospasm. Isolated endothelium-intact IMA and RA rings precontracted with KCl (30 mM) rapidly dilated to hypoxia (95% N(2)/5% CO(2)) with a greater relaxation in RA than IMA. Inhibitors of cyclooxygenase (10 microM indomethacin) and the thromboxane A(2) (TxA)(2) receptor [1 microM [1S-[1alpha,2alpha(Z),3alpha,4alpha]]-7-[3-[2-(phenylamino)carbonyl]hydrazine]methyl]-7-oxabicyclo[2.

Open pulmonary embolectomy for treatment of major pulmonary embolism.

Background: Inadequate data exist regarding the management of acute major pulmonary embolism. Various modalities that are used, including thrombolytics and embolectomy, have not been shown to conclusively improve mortality when compared to heparin. In the past, open pulmonary embolectomy was reserved for patients with severe hemodynamic instability because of its high mortality rate.

Malignant renal tumor with extension to the inferior vena cava.

Background: Management of malignant renal tumors involving the inferior vena cava (IVC) depends on tumor extension within the cava.

Methods: Of 295 patients treated for renal cancer, propagation of tumor mass through the renal vein to IVC was seen in 22 (7%) patients. Cephalad extension of the tumor was suprarenal: infrahepatic in 12, retrohepatic in 6, and within the right atrium in 4 patients.