Springfields study-reply

Abstract

Dear SirDr Kalman correctly stresses the importance of responding to the health and safety concerns of workers in the nuclear industry. However, the statements that we dismissed comparisons of cancer rates among Springfields workers to national rates, and that such analyses provide `real information' of greater importance to BNFL employees than internal analyses of cancer rates, are perhaps misleading. In our editorial we simply reported the fact that the paper by McGeoghegan and Binks focused on internal analyses that compared cancer rates between workers who accrued different levels of cumulative external radiation dose [1]. Scientists, as well as worker and community groups, have previously raised concerns about the problems of bias that can occur when workers' death rates are compared to national rates [2-5]. Briefly, the exclusion from employment of people with medical problems, and the socioeconomic advantages of some workers, may lead to the observation of relatively low death rates in an occupational cohort and mask evidence of occupationally-induced disease. Internal comparisons are often conducted, as noted by McGeoghegan and Binks [6], in order to avoid the bias. In their internal analyses, cancer rates among workers with high levels of exposure were compared to cancer rates among workers with low levels of exposure. Such analyses can provide insight into whether cancer rates increase among workers with increasing levels of exposure. The observation that, overall, cancer rates are not substantially elevated among Springfields workers compared to national rates, therefore, may be of less interest to workers than the finding that cancer rates are higher among workers with higher external radiation doses. In our editorial, we suggested that this trend may at least partially reflect confounding due to other occupational exposures (such as internal exposure to ionizing radiation) which may have been received at higher levels among workers who also received higher external radiation doses. From an occupational health and safety perspective, however, the observation of increasing cancer rates associated with an occupational exposure (whether independently, or in conjuction with other exposures) is of more than `academic' interest. Yours faithfully,

Onconase and Amphinase, the Antitumor Ribonucleases from Rana pipiens Oocytes

“…Although amino acid sequences of Onc and Amph variants are only 30 and 24.8 -28%, respectively, identical to that of RNase A, the general folds of the three enzymes are very similar. Onc [38] and Amph-2 [2] adopt the classic bilobal, V or kidney shaped topology of RNase A [42,43] formed by two 3-stranded antiparallel (β-sheets and three α-helices. Helices α2 and α3 flank the two (β-sheets shielding them from water and helix α1 is located in the middle of the v-motif and makes contacts to both lobes [39].…”