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Biomedical subjects

K van Doorn

Publications and source records attributed to K van Doorn.

3 recordsLinked to original sources

The effects of lathyrogens on intestinal anastomoses in the rat.

Submucosal collagen provides strength to the intestinal wall. In order to assess the importance of collagen fibers for the developing strength of intestinal anastomoses we have sought to prevent postoperative collagen crosslinking by administration of lathyrogens. Rats, receiving both an ileal and a colonic anastomosis, were treated with either D-penicillamine or beta-aminopropionitrile from 1 day before operation. Animals were sacrificed 7 days postoperatively and bursting pressures, bursting sites, and anastomotic collagen (hydroxyproline) content and solubility were determined. D-Penicillamine, in a dose of 500 mg/kg/day and administered orally, had no effect at all. beta-Aminopropionitrile, in a dose of 625 mg/kg/day and given orally or intraperitoneally, significantly increased the acid solubility of anastomotic hydroxyproline in both ileum and colon without affecting total hydroxyproline content or concentration. Bursting pressures of the anastomotic segments were lowered, more significantly in colon than in ileum. Also, the bursting site was found more frequently in the anastomotic area in these animals. By inhibiting the formation of crosslinks in intestinal wounds with beta-aminopropionitrile, the anastomotic strength was reduced. These results demonstrate the importance of collagen in maintaining anastomotic integrity and at the same time emphasize that not only the quantity but also, and perhaps even more so, the quality of the collagen should be taken as an index of healing.

Aminopropionitrile↗

Surface-area increase in tissue expansion.

In this paper, the subject of surface-area gain in tissue expansion is approached from three sides. With the help of a mathematical approach, the theoretical increase in surface area was calculated in relation to the specifications of the expanders. In an in vitro model, these mathematical data were confirmed to be reliable. To determine the real surface-area gain that takes place in vivo, measurements on pigs were performed. It appears that only about 35 percent of the mathematically expected increase in surface area takes place. Moreover, a clear difference was observed between the surface-area gain for the different shapes of tissue expanders.

Animals↗

Electromagnetic flow-probe implantation for cardiac output measurements in rabbits.

A technique suitable for continuous measurement of beat-to-beat cardiac output in conscious rabbits for relatively longer periods is described. The method consists, essentially, of implanting a specially constructed electromagnetic flow probe around either the pulmonary artery or the aorta during left thoracotomy (second intercostal space) in animals anesthetized with hypnorm. With care, the procedure is successful in a large proportion of the animals. Little postoperative care is required and the flow probe remains functional for several weeks up until the animals were killed to recover the probe for reimplantation. The cardiac output values (ml/min/kg) in conscious rabbits were: normal 183 +/- 9; unilateral renal hypertensive animals, 108 +/- 10 and bilateral renal hypertensive animals, 153 +/- 15. Isoprenaline increased, and propranolol decreased, the cardiac output in conscious normotensive rabbits.

Animals↗