On the fate of the secondary white dwarf in double-degenerate double-detonation Type Ia supernovae

The progenitor systems and explosion mechanism of Type Ia supernovae are still unknown. Currently favoured progenitors include double-degenerate systems consisting of two carbon-oxygen white dwarfs with thin helium shells. In the double-detonation scenario, violent accretion leads to a helium detonation on the more massive primary white dwarf that turns into a carbon detonation in its core and explodes it. We investigate the fate of the secondary white dwarf, focusing on changes of the ejecta and observables of the explosion if the secondary explodes as well rather than survives. We simulate a binary system of a $1.05\,M_\odot$ and a $0.7\,M_\odot$ carbon-oxygen white dwarf with $0.03\,M_\odot$ helium shells each. We follow the system self-consistently from inspiral to ignition, through the explosion, to synthetic observables. We confirm that the primary white dwarf explodes self-consistently. The helium detonation around the secondary white dwarf, however, fails to ignite a carbon detonation. We restart the simulation igniting the carbon detonation in the secondary white dwarf by hand and compare the ejecta and observables of both explosions. We find that the outer ejecta at $v>15000\,\mathrm{km\,s^{-1}}$ are indistinguishable. Light curves and spectra are very similar until $\sim 40$d after explosion and the ejecta are much more spherical than for violent merger models. The inner ejecta differ significantly which slows down the decline rate of the bolometric light curve after maximum of the model with a secondary explosion by about 20 per cent. We expect future synthetic 3D nebular spectra to confirm or rule out either model.Comment: 12 pages, 7 figures, submitted to MNRAS, comments welcom

p53 protein overexpression: A strong prognostic factor in uterine papillary serous carcinoma

Uterine papillary serous carcinoma (UPSC) is an uncommon but aggressive type of endometrial cancer associated with rapid progression of disease and poor prognosis. We investigated 23 cases of UPSC. p53 expression was studied in archival paraffin-embedded tissue by immunohistochemistry. Eleven tumors (47.8%) showed p53 overexpression whereas 12 tumors (52.2%) were p53 negative. One of 8 stage I/II (12.5%) and 10/15 stage III/IV (66.6%) tumors revealed p53 staining (P = 0.027). The median overall survival was 43.3 months. Patients with advanced-stage (III, IV) disease had a 5-year overall survival probability (5-year OS%) of 24% compared to 100% in those in stages I and YI (log-rank, P = 0.018). Myometrial invasion, lymphatic space invasion, or lymph node involvement did not correlate with the 5-year OS of these patients. Patients whose tumors overexpressed p53 had a significantly shorter survival than those whose tumors did not (P = 0.033). This study confirms the influence of p53 overexpression on survival in UPSC patients, (C) 1998 Academic Press

Impact of hysteroscopy on disease-free survival in clinically stage I endometrial cancer patients

Recent data strongly suggest tumor cell dissemination of endometrial carcinoma cells in the course of fluid hysteroscopy. In patients who had endometrial cancer which was (except for peritoneal cytology) confined to the uterus, the disease free survival (DFS) of 135 patients who underwent hysteroscopy prior to staging laparotomy was compared with the DFS of 127 patients without hysteroscopy. After a median follow-up of 23 months, 10 patients experienced tumor recurrence. Although there was a trend towards a higher incidence of positive peritoneal cytology at laparotomy in patients who underwent hysteroscopy, this difference did not achieve statistical significance (P = 0.47). For 5 years, the DFS was 92.4% in patients with hysteroscopy and 84.7% in patients without hysteroscopy before laparotomy (log-rank, P = 0.782). Our data therefore suggest a similar short-term DFS in endometrial cancer patients with and without hysteroscopy prior to laparotomy

Endometrial cancer: accuracy of the finding of a well differentiated tumor at dilatation and curettage compared to the findings at subsequent hysterectomy

The objective of this study was to examine the accuracy of the finding of a histologically well differentiated endometrial carcinoma at dilatation and curettage (D & C) prior to hysterectomy. A retrospective multicentric chart review of 137 endometrial cancer patients was conducted, including all patients in whom a well differentiated endometrial carcinoma had been diagnosed by D & C. Histopathologic grading as determined by D & C was compared with the grading established at the final histologic examination after hysterectomy. Seventy-eight percent of all cases in which a well differentiated tumor was diagnosed with D & C were confirmed as well differentiated endometrial carcinomas, whereas 20.4% had to be upgraded as moderately differentiated tumors after evaluation of the hysterectomy specimen. In one case in which a uterine adenocarcinoma was diagnosed by D & C, a well differentiated adenocarcinoma was found to be combined with a carcinosarcoma in the hysterectomy specimen. In order to avoid false findings of a well differentiated tumor, the histologic grade should be confirmed by intraoperative frozen section examination. This is especially important in cases in which surgical staging was not planned initially