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TUNDRA RED SHIFT
Jorge Luis is now a consultant with Tundra Wines, who have used the wonders of biotechnology to develop the Supreme Grape. They expect to produce a healthy red wine that would entice Canadians to give up on imported wines. As part of their scientific approach to the problem, they have set up a Vascular Lab to explore the effects of grape products on smooth muscle function, since there is evidence that consumption of red wine is protective against coronary artery disease.
Jorge Luis sets up rat aortic rings in physiological salt solutions and records isometric tension in response to different agonists. He finds that arteries precontracted with norepinephrine (NE), promptly relax when treated with a 1:100 dilution of Tundra Red Extract (TREX) (see Fig 1).
He compares the responses of intact aortic rings with those that have been denuded of endothelium by gently rubbing the luminal surface with curved forceps. In these experiments, the rings were pre-incubated for 15 mins with a 1:100 dilution of the Extract.The results are shown in Table 1.
Tundra Red induced relaxation of aortic rings
Condition % Relaxation Endothelium Intact 88 + 3 Endothelium Removed 5 + 2
Finally he compares the relaxing effects of a variety of products, all used in the same concentration (see table 2).
Vascular Relaxing Effects of Different Grape Products
PRODUCT % Relaxation Grape Skin Extract (red) 100 Grape Skin Extract (white) 96 + 4 Tundra Red Extract 100 Cabernet Sauvignon (red) 86 + 3 Burgundy (red) 88 + 3 Bordeaux (white) 0 Chardonnay (white) 10 + 2
This problem used a study that had been published in the American Journal of Physiology (Fitzpatrick et al, Am J Physiol 265: H774-H778, 1993). I reworked it to use the character Jorge Luis who had appeared in one of the earlier problems. Again many different explanations are possible.