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Rectal carcinoma is common, with considerable local recurrence and death rates. Preoperative radiotherapy and refined surgical techniques can improve local control. The aim of this study was to investigate the interaction between apoptosis and the outcome of rectal carcinoma, with and without short-term preoperative radiotherapy. Specimens were from 162 patients from the Southeast Swedish Health Care region included in the Swedish Rectal Cancer Trial between 1987–1990. New sections from the paraffin blocks of the preoperative biopsies and the surgical specimens were examined for apoptosis using the terminal deoxynucleotidyl transferase mediated digoxigenin nick end labeling (TUNEL) method. The mean percentage of apoptotic cells was 0.3% (0–4%) and 1.1% (0–14.5%) for the preoperative biopsy and the surgical specimen, respectively. The authors analyzed the surgical specimens from nonirradiated patients and divided them into three groups by apoptotic index (AI) as follows: 0%, 0–1%, and > 1%. A high AI was associated with a decreased local recurrence rate compared with an intermediate or a low AI (P = 0.024). There was no significant relation between AI and survival. There was a significant reduction in the local recurrence rate for irradiated patients compared with the nonirradiated in the low (P = 0.015) and intermediate (P = 0.038) AI groups. In the high AI group, there were few recurrences and no significant difference was observed between irradiated and nonirradiated patients. The relative risk of death from rectal carcinoma in Dukes A–C patients was not significantly decreased by radiotherapy, but, in the intermediate AI group, there was a trend (P = 0.08) in favor of the irradiated patients. A high AI in rectal carcinoma indicated a decreased local recurrence rate. Cancer 2001;91:1870–5. © 2001 American Cancer Society.

Larval competition experiments involving two wild type and eight mutant strains of Drosophila melanogaster have been carried out following the substitution procedure proposed by Mather and Caligari (1981). Our main goal has been to compare the competitive abilities of two phenotypically indistinguishable strains (wild and Oregon-R) by means of their responses with eight different mutants. Prior to the analyses of viability data, we have studied the normalizing effect of several transformations in order to determine which was best suited for the analyses. The differences found among the five transformations tested and the untransformed data were not very great. The folded power transformation (Mosteller and Tukey, 1977) was finally chosen.No constant pattern in the responses of the two wild type strains to the mutant competitors was detected. This leads us to conclude that the nature of the competition between the two wild type strains cannot be predicted from a knowledge of their competition with other strains.