Coronary vasoconstriction to endothelin-1 increases with age before and after ischaemia and reperfusion.

OBJECTIVE: Ageing is known to be associated with changes within the heart. We investigated whether the coronary response to endothelin-1 (ET) and sarafotoxin S6c (S6c) is altered with increasing age, before and after cardioplegic arrest. METHODS: Using an isolated rat heart model, increasing concentrations of ET and S6c were administered to rats of different ages (group I = one month; group II = five months; group III = 21 months). An identical series of experiments was performed following the addition of indomethacin and NG-nitro-L-arginine methyl ester (L-NAME) to the Krebs perfusion fluid. In a third series of experiments, increasing doses of ET-1 were added to hearts following 4 h of cardioplegic arrest at 4 degrees C. RESULTS: Coronary flows are expressed as a percentage of initial coronary flow +/- SEM. There was a greater decrease in coronary flow in the older rats for all doses of ET-1. ET-1 (10(-9) M) reduced coronary flows to 72.8 +/- 3.7, 53.2 +/- 6.7 and 56.5 +/- 10.7% for groups I-III respectively (P = 0.01 I vs. II; P = 0.1 I vs. III). A similar response to ET-1 was seen in hearts perfused with indomethacin and L-NAME when compared to those perfused without (P = NS). Perfusion with ET-1 (10(-9) M) following 4 h of cardioplegic arrest reduced coronary flows to 40.5 +/- 4.9, 26.8 +/- 4.8 and 24.1 +/- 3.9%, respectively (P = 0.08 I vs. II; P = 0.03 I vs. III). Perfusion with S6c (10(-10) M) produced coronary flows of 93.3 +/- 5.5, 77.0 +/- 3.5 and 73.9 +/- 3.9% for groups I-III, respectively (P = 0.03 I vs. II; P = 0.01 I vs. III). Perfusion with S6c (10(-9) M) in the presence of L-NAME and indomethacin reduced coronary flows to 85.7 +/- 3.0, 81.6 +/- 2.2 and 74.6 +/- 3.6% (P = NS I vs. II; P = 0.03 I vs. III). CONCLUSIONS: The coronary vasoconstrictor response to ET-1 and S6c increases with age. The increased vasoconstriction in response to ET-1 is independent of the decrease in NO release seen with ageing.

Tricuspid valve repair in a mountaineer.

Lord Hunt of Everest presented with aortic stenosis but predominant right ventricular failure. He was found to have signs of pulmonary hypertension with a dilated right ventricle, severe tricuspid regurgitation, and right atrial hypertrophy in the absence of elevated pulmonary artery pressures. He is a lifelong mountaineer and we attribute these findings to intermittent prolonged exposure to high altitude.

Comparison of the morphologic and vascular reactivity of the proximal and distal radial artery.

BACKGROUND: Variations in the morphology and vascular reactivity of the proximal and distal radial artery might influence its performance as a bypass conduit. METHODS: The morphologic and functional characteristics of the proximal and distal RAs were compared with those of the left and right internal mammary arteries by using histologic and in vitro organ bath techniques. RESULTS: Proximal RA had a significantly greater medial cross-sectional area compared with that of the distal RA (2.48+/-0.27 mm2 compared with 1.86+/-0.21 mm2, p< 0.05), which were both significantly greater than the left internal mammary artery (0.54+/-0.09 mm2) or the right internal mammary artery (0.67+/-0.03 mm2). Proximal RA had a significantly greater response to 90 mmol/L potassium chloride than that of distal RA (88.4+/-7.3 compared with 60.2+/-10.3 mN, p<0.05), and both contracted more than the left internal mammary artery (30.3+/-2.9 mN) and the right internal mammary artery (32.6+/-4.1 mN). There was no difference in the response to noradrenaline and adrenaline between proximal and distal RA, both of which contracted more than the left and right internal mammary arteries. CONCLUSIONS: When choosing a segment of RA for use as a bypass conduit, regional variations in biologic properties should be considered.

Extramedullary plasmacytoma presenting with myasthenia gravis and mediastinal mass.

A 68-year-old woman presented with myasthenia gravis and an anterior mediastinal mass, which proved to be an extramedullary plasmacytoma in the thymus with associated extracellular light chain deposition. Further specimens revealed plasma cell proliferation in an internal thoracic lymph node and in a subsequent colectomy specimen, indicating systemic disease. This case demonstrates the rare association between a plasmacytoma in the thymus and myasthenia gravis.