Pelvic exenteration.

Sixty-eight patients at the University of Illinois, Cook County, and the West Side Veterans Administration hospitals underwent pelvic exenteration for advanced pelvic malignancies during the 15-year period from 1969 to 1984. Thirty-two had colorectal cancers, eleven cervical, seven bladder, and six vulvar; in twelve the cancers were in miscellaneous pelvic sites. Forty-five exenterations were done with intent to cure, and twenty-three for palliation of patients with bulky, necrotic tumors that had caused symptomatic fistulae, local sepsis, chronic bleeding, or severe localized pain. The total 30-day postoperative mortality was 4.4% (3/68). The 5-year survival rate of patients who underwent curative exenteration was 33% (median 27 months). Pelvic exenteration appears to be a feasible surgical procedure for a variety of advanced malignancies as well as for palliation of severely symptomatic patients.

Chromosome-bound mitotic factors: release by endonucleases.

Additional evidence is presented to support our recently reported conclusion that the mitotic factors of mammalian cells, which induce germinal vesicle breakdown and chromosome condensation when injected into fully grown Xenopus laevis oocytes, are localized on metaphase chromosomes. Chromosomes isolated from mitotic HeLa cells were further purified on sucrose gradients and digested for varying periods with either the micrococcal nuclease or DNase II. At each time point of digestion the amount of mitotic factors released was determined by injecting a supernatant of these fractions, obtained by high-speed centrifugation, into oocytes. The amount of DNA rendered acid soluble under the conditions of digestion used was 3% ot 5% of the total chromosomal DNA. The extent of release of mitotic factors with both nucleases was estimated to be about 30% to 40% as evidenced by the reextraction of the undigested chromosomal pellet with 0.2 M NaC1. Similar results were obtained when nuclei from G2 cells were digested under identical conditions. The release of these chromosome-bound mitotic factors by mild digestion with these nucleases though only partial, clearly demonstrates that a significant proportion of these factors are localized on metaphase chromosomes.

Effect of adrenal manipulation on glucocorticoid receptors in MM1 hamster melanoma.

Cytosol glucocorticoid receptor of hamster Malignant Melanoma No. 1 (MM1) was characterized by dextran-coated charcoal and sucrose gradient assays. MM1 contains a specific, saturable, high-affinity (Kd 2.5 nM; 73.3 fmol/mg cytosol protein) receptor for glucocorticoid. The receptor sedimented at 7 to 8S in low-salt buffer and 5.5S in 0.4 M KCl and was sensitive to proteolysis by trypsin. Glucocorticoid receptor was inactivated by 40% (NH4)2SO4. Addition of 20 mM molybdate to the homogenizing buffer prevented inactivation. Adrenalectomy increased MM1 receptor content without altering affinity. Chronic exposure of intact or adrenalectomized hamsters to gluco- and high-dose mineralocorticoid significantly decreased the amount of unbound glucocorticoid receptors available for binding. Exposure of intact hamsters to high doses of mineralocorticoid also decreased apparent receptor affinity. These results suggest that hamster MM1 contains a high-affinity cytosol receptor for glucocorticoids similar to that of other glucocorticoid-responsive tissues, which may mediate the action of adrenal steroids on tumor behavior.

Localization of mitotic factors on metaphase chromosomes.

The objective of this study was to determine whether the mitotic factors of HeLa cells, which induce meiotic maturation, i.e. germinal vesicle breakdown (GVBD) and chromosome condensation, when injected into fully grown Xenopus laevis oocytes, were localized in the cytoplasm or associated with the metaphase chromosomes. Cytoplasmic extracts were prepared by lysing mitotic HeLa cells in low-salt hypotonic buffer and separating the chromosomes by centrifugation. Th mitotic factors bound to chromosomes were extracted with high-salt (0.2 M-NaCl) buffer. Both the cytoplasmic and chromosomal protein fractions were evaluated for their maturation-promoting activity (MPA) in the Xenopus oocytes. The results of this study indicate that both the cytoplasmic and chromosomal fractions are identical in many respects, including their ability to induce GVBD, but the specific activity of the chromosomal fraction was at least threefold greater than that of the cytoplasmic fraction. These data suggest that a major portion of the mitotic factors is localized on the metaphase chromosomes. This association does not appear to be due to adventitious binding of mitotic proteins to chromosomes during the extraction procedures. Furthermore, when extracts were prepared in a similar way from early- and mid-G2-phase HeLa cells, only the nuclear extracts had MPA and no activity was found in the cytoplasmic fraction. Both the cytoplasmic and nuclear extracts of late-G2 cells exhibited MPA. These data support the conclusion that the mitotic factors become preferentially bound to chromatin as soon as they are synthesized, and as the cell synthesizes more of these factors in preparation for mitosis, increasing amounts of them are retained in the cytoplasm.

Influence of the estrous cycle during carcinogen exposure on nitrosomethylurea-induced rat mammary carcinoma.

The influence of individual stages of the rat estrous cycle during exposure to I-nitroso-I-methylurea (NMU) on mammary tumor incidence, latency, number, and cytosol receptor dynamics for estrogen and progesterone was determined. Virgin female Buffalo rats were separated into three groups on Day 53 according to their vaginal smear pattern. NMU (5 mg/100 g body weight, i.v.) was administered in three monthly doses beginning at 53 to 55 days of age on diestrus, proestrus, or estrus between 9:00 and 11:00 a.m. Groups of rats had their second and third injections of NMU on the same day of the estrous cycle as their initial injection. All animals were killed during the morning on a diestrus day. Receptors for estrogen and progesterone were determined by a modified dextran-coated charcoal method and by sucrose density gradient analysis. Mean latencies to first tumor appearance in diestrus, proestrus, and estrus groups were 104.4, 83.6, and 91.4 days, respectively (p less than 0.05, diestrus versus estrus and proestrus) following the first NMU injection. The mean number of tumors per rat was significantly higher in rats injected on proestrus (4.5) or estrus (4.3) than on diestrus (2.0). Estradiol bound to receptor sedimented at 8 and 4 s and was suppressed by diethylstilbestrol and estradiol. Progesterone receptor migrated to 7.8 and 4 s regions. Estrogen receptor incidence (100%) and content (16.7 fmol/mg cytosol protein) was highest in rats injected on diestrus. In the proestrus and estrus injected groups, estrogen receptor incidence was 95 and 63% and content was 10.2 and 11.2 fmol/mg protein, respectively. The affinity of estradiol for its receptor was not significantly altered in any group. Although there were no statistically significant difference in progesterone receptor incidence or affinity between groups, progesterone receptor content (74.6 fmol/mg cytosol protein) was significantly higher in tumors from rats injected on proestrus than on diestrus. These data suggest that the prevailing hormonal milieu of the estrous cycle during NMU exposure may be critically important to the subsequent biological behavior and steroid receptor status of carcinogen-induced rat mammary tumors.