Biomedical subjects
Publications and source records attributed to A H Rathjen.
Future problems facing otolaryngologists who use alloplastic implants are identified in this article. Unless responsible device manufacturers, the governmental regulatory agencies, the medical community, the legal profession, and the public recognize how these problems are reducing the availability of devices used by otolaryngologists, as well as other medical specialties, the potential benefits of these devices will not be realized.
Bruce's Sport is a mutant grapevine (Vitis vinifera L.) with green and white variegated fruit derived from the Sultana variety. The white regions of tissue have decreased polyphenol oxidase (PPO) activity resulting in a reduced capacity for browning. Active PPO from Sultana grapes was purified and had an apparent molecular weight of 40,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Western blots indicated that mature Sultana grapes contained a single 40-kilodalton PPO, and young Sultana berries also had small quantities of a 60-kilodalton protein. Bruce's Sport grapes had much less of the 40-kilodalton PPO and greater amounts of the 60-kilodalton band. Protease digestion of Bruce's Sport extracts decreased the proportion of the 60-kilodalton protein and increased the 40-kilodalton band. A cDNA clone of grape PPO was used to probe a northern blot of Sultana and Bruce's Sport RNA and hybridized to a 2.2-kilobase transcript in both grapevines. The level of PPO mRNA was high in the early stages of berry development but then declined. The results suggest that in grapevine the active 40-kilodalton form of PPO is synthesized as a precursor protein of at least 60 kilodaltons, and normal processing is interrupted in Bruce's Sport resulting in the accumulation of the 60-kilodalton inactive preform of PPO.