Genotoxicity of polychlorinated biphenyls (PCBs): recombinogenesis by biotransformation products

A coplanar polychlorinated biphenyl (PCB) when eaten by test animals increased the rate of recombination in somatic cells, indicating a new mechanism of action for these compounds. Using the eye-mosaic test a high bioactivation strain of Drosophila that consumed 4,4'-dichlorobiphenyl (4,4'-DCB) manifested a genotoxicity rate that was three-fold greater than that in animals fed the solvent-spiked medium. This compound was not genotoxic in a suppressed bioactivation strain indicating that genotoxicity requires bioactivation of the compound. High bioactivation test strains made heterozygous for a paracentric inversion, a chromosomal rearrangement that suppresses homologous recombination, exhibited significantly reduced genotoxicity after treatment.

Experience with radical prostatectomy and radiation therapy for localized prostate cancer at a Veterans Affairs Medical Center

We assessed the actuarial survival of 357 patients with localized prostate cancer who were treated with radical prostatectomy or radiation therapy at a Veterans Affairs Medical Center between 1980 and 1991 and who were followed for a median of 59 months. During this period patients with clinical stages A2 and B tumors who had an anticipated life expectancy of 10 years or greater were generally treated with surgery. Patients with stages A2 and B tumors who were not candidates for surgery and those with stage C tumors were generally treated with radiation therapy. There were no significant differences among the cause specific, clinical disease-free and prostate specific antigen disease-free survival curves of patients with stages A2 and B tumors who were treated with radical prostatectomy (138) or radiation therapy (138) but the all cause and metastases-free survival curves favored the surgery group (p < 0.000001 and 0.046, respectively). There was no significant difference between the all cause survival curves of the patients with stages A2 and B tumors and of 81 patients with stage C tumors who were treated with radiation therapy. However, the cause specific survival curves favored the patients with stages A2 and B tumors (p = 0.000007). This study demonstrates that there is a high risk of death from co-morbidities in a hospital based population of American veterans with localized prostate cancer who are not candidates for radical prostatectomy.

Prostate specific antigen progression rates after radical prostatectomy or radiation therapy for localized prostate cancer

BACKGROUND

The purpose of the study was to determine whether a difference is noted in the rate of prostate specific antigen (PSA) elevation after radical prostatectomy or radiation therapy for localized prostate cancer.

METHODS

PSA doubling times were calculated by linear regression analysis in 50 patients who had been treated by radical prostatectomy and who had three or more increasing PSA levels and in 55 patients who had been treated with radiation therapy and who had three or more increasing PSA levels.

RESULTS

No significant difference was noted in the mean PSA doubling times in the two patient groups when stratified by the site of tumor recurrence or by pretreatment tumor stage, tumor grade, or acid phosphatase level.

CONCLUSIONS

Because the PSA doubling time probably parallels the tumor growth rate, these data suggest that the malignant potentials of recurrent tumor after radical prostatectomy and after radiation therapy are equivalent.

Results of partial patellectomy

We present an assessment of 200 patellar fractures treated mostly (175) by partial patellectomy. In 23 cases in which the quadriceps mechanism was 75% intact (MRC power approximately 4), the fractures were treated conservatively, with an overall acceptable result. The operative series with an average follow-up of 3 years has shown 80.3% excellent to good results. A classification of fractures of the patella, based on the anatomical fracture line and quadriceps functional loss as recorded in 690 case histories, is suggested.