Author index to volume 154

Horseradish peroxidase-catalyzed N-demethylation of aminopyrine and dimethylaniline results in generation of free radical intermediates which can interact with glutathione (GSH) to form a glutathione radical. This can either dimerize to yield glutathione disulfide or react with O₂ to form oxygenated products of glutathione. Ethylmorphine is not a substrate in the peroxidase-mediated reaction, and free radical intermediates which react with GSH, are not formed from aminopyrine and dimethylaniline when the horseradish peroxidase/H₂O₂ system is replaced by liver microsomes and NADPH. Therefore, it appears unlikely that formation of free radical intermediates can be responsible for the depletion of GSH observed during N-demethylation of several drugs in isolated liver cells.     

Recording,processing and analysis of grass root images from a rhizotron

To develop and test a system for computer-assisted image analysis, repeated video recordings of reed canary-grass roots (Phalaris arundinacea L.) were made in an 18-window rhizotron. The images were digitized and processed using a Unix computer and the Khoros software development environment.Two image sizes, 126×95 mm and 61×46 mm, both comprising 650 × 490 pixels, were compared. Among image processing techniques used were median filtering, segmentation and skeletonization. Root area and length in both the topsoil and subsoil were estimated using the two image sizes. The resolution (image size) strongly affected the calculated root lengths. The results were compared with root length measurements obtained manually.Statistically significant differences in root length and area in the topsoil were detected between the sampling dates using the computer-assisted methods. Possible sources of error and methods for reducing them are discussed.     

Microvascular anastomoses in irradiated vessels: a comparison between the Unilink system and sutures

A new mechanical device (the Unilink system) was compared to conventional suture anastomoses in irradiated microvessels. Twenty rabbits received a single radiation dose of 20 Gy from a 7-MeV electron source through an anterior neck field. One and 6 months following irradiation, the carotid arteries and facial veins were divided and anastomosed on one side with the Unilink system and on the other side with suture technique. At sacrifice 4 weeks postoperatively, all vessels were evaluated for patency and histologic changes associated with radiation and anastomotic trauma. Histology disclosed severe radiation changes. Also, intimal hyperplasia was consistently found at the anastomotic sites in the arteries, while it was totally absent in the venous anastomoses. Occlusive thrombosis was found in two arteries, one anastomosed with the Unilink system and one sutured. Two other arteries, one from each group, had subtotal occlusions at the anastomotic site. No occlusions occurred in any of the venous anastomoses. The overall patency in this study was 97.5 percent, with no difference between the two techniques.