The dispersion-brightness relation for fast radio bursts from a wide-field survey.

Despite considerable efforts over the past decade, only 34 fast radio bursts-intense bursts of radio emission from beyond our Galaxy-have been reported1,2. Attempts to understand the population as a whole have been hindered by the highly heterogeneous nature of the searches, which have been conducted with telescopes of different sensitivities, at a range of radio frequencies, and in environments corrupted by different levels of radio-frequency interference from human activity. Searches have been further complicated by uncertain burst positions and brightnesses-a consequence of the transient nature of the sources and the poor angular resolution of the detecting instruments. The discovery of repeating bursts from one source3, and its subsequent localization4 to a dwarf galaxy at a distance of 3.7 billion light years, confirmed that the population of fast radio bursts is located at cosmological distances. However, the nature of the emission remains elusive. Here we report a well controlled, wide-field radio survey for these bursts. We found 20, none of which repeated during follow-up observations between 185-1,097 hours after the initial detections. The sample includes both the nearest and the most energetic bursts detected so far. The survey demonstrates that there is a relationship between burst dispersion and brightness and that the high-fluence bursts are the nearby analogues of the more distant events found in higher-sensitivity, narrower-field surveys5.

Sexual calling behavior in primitive ants.

The wingless virgin females of the ponerine ant Rhytidoponera metallica attract males by the release of a pheromone from the tergal gland, a hitherto unrecognized exocrine gland located between the last two abdominal segments. This is the first evidence for sexual chemical communication in the large and primitive subfamily Ponerinae.

Radiation Necrosis in Pediatric Patients with Brain Tumors Treated with Proton Radiotherapy.

BACKGROUND AND PURPOSE: Proton radiotherapy has been increasingly utilized to treat pediatric brain tumors, however, limited information exists regarding radiation necrosis among these patients. Our aim was to evaluate the incidence, timing, clinical significance, risk factors, and imaging patterns of radiation necrosis in pediatric patients with brain tumors treated with proton radiation therapy. MATERIALS AND METHODS: A retrospective study was performed on 60 consecutive pediatric patients with primary brain tumors treated with proton radiation therapy. Radiation necrosis was assessed by examining serial MRIs and clinical records to determine the incidence, timing, risk factors, imaging patterns, and clinical significance associated with the development of radiation necrosis in these patients. Radiation necrosis was defined as areas of new enhancement within an anatomic region with previous exposure to proton beam therapy with subsequent decrease on follow-up imaging without changes in chemotherapy. RESULTS: Thirty-one percent of patients developed radiation necrosis with a median time to development of 5.0 months (range, 3-11 months). Risk factors included multiple chemotherapy agents (>3 cytotoxic agents) and atypical teratoid rhabdoid tumor pathology (P = .03 and P = .03, respectively). The most common imaging patterns were small (median, 0.9 cm) and multifocal (63% of patients) areas of parenchymal enhancement remote from the surgical site. The median time to complete resolution on imaging was 5.3 months (range, 3-12 months). Among patients with imaging findings of radiation necrosis, 25% demonstrated severe symptoms with medical intervention indicated. CONCLUSIONS: Pediatric patients with brain tumors treated with proton radiation therapy demonstrate a high incidence of radiation necrosis and a short time to development of necrosis. Multiple small areas of necrosis are frequently identified on imaging. Exposure to multiple chemotherapy agents was a significant risk factor associated with radiation necrosis in these patients.

Repair of traumatic rupture of the aortic valve.

Traumatic aortic valve rupture is a rare complication of nonpenetrating cardiac injury and can be caused by a tear or avulsion of the valve. The most common method of treatment has been valve replacement, although valve repair has been successful in a few cases of cusp tear or detachment. We report a case of aortic valve commissural avulsion in which a reparative technique was applied and the natural valve was preserved.

Intramural leiomyoma during pregnancy becoming pedunculated postpartally. A case report.

BACKGROUND: The natural history of uterine leiomyomas during pregnancy has been reported. CASE: A 39-year-old primigravida presented with vaginal spotting in the 10th week of pregnancy. Ultrasonic evaluation revealed a large intramural leiomyoma. Unsuccessful tocolysis at 25 weeks' gestation resulted in a cesarean section for breech presentation. At hysterotomy a 10-cm intramural leiomyoma was found in the right fundus and was left in situ. Six months later, at open laparotomy for myomectomy, the 10-cm leiomyoma was pedunculated, on a 4-cm stalk. CONCLUSION: Large intramural leiomyomas found at cesarean section may become pedunculated postpartally, thus making myomectomy easier and safer at a postpartum intervention than at the time of cesarean section. Also, prior knowledge of the possibility of myoma transformation from intramural to pedunculated postpartally may help in planning a later myomectomy. Myomectomy prior to pregnancy should be considered when it has caused a prior pregnancy complication.

Blepharoplasty under hypnosis: a personal experience.

This paper is a first-hand account of my experience undergoing upper and lower blepharoplasty surgery in which hypnosis was used as the primary sedative agent. It describes the basics of hypnosis. It also includes a description of how I prepared myself for surgery as well as how I helped the surgical team prepare for this surgery. Recommendations are offered for nurses who would like to incorporate hypnotherapy into the operating room.

Combination chemotherapy for mycosis fungoides: a Southwest Oncology Group study.

Between 1972 and 1977, the Southwest Oncology Group studied the following three chemotherapy programs for the treatment of patients with advanced forms of mycosis fungoides: (a) cyclophosphamide, adriamycin, vincristine, and prednisone (CHOP) (seven patients); (b) adriamycin, vincristine, and prednisone (HOP) (five patients); and (c) cyclophosphamide, vincristine, prednisone, and bleomycin (COP plus bleomycin) (12 patients). Among the 24 evaluable patients there was an overall objective response rate of 95% with seven (29%) achieving a complete remission. With the adriamycin-containing chemotherapy, five (42%) of 12 patients achieved a complete remission compared to two (17%) of 12 patients treated with COP plus bleomycin. The median duration of remission (partial plus complete) was longer with the COP plus bleomycin combination (median, 47 weeks) than with the adriamycin-containing combinations (median, 22 weeks; P = 0.03). The median survival for all 24 evaluable patients was 95 weeks and was similar regardless of remission-induction therapy. In summary, combination chemotherapy proved to be effective palliative therapy for advanced mycosis fungoides.

Superiority of adriamycin-containing combination chemotherapy in the treatment of diffuse lymphoma: a Southwest Oncology Group study.

As a part of an ongoing prospective controlled trial, the Southwest Oncology Group compared the results of treatment of advanced non-Hodgkin's lymphoma with two CHOP regimens (cyclophosphamide, adriamycin, vincristine and prednisone with either low-dose bleomycin or BCG by scarification) to a COP regimen (cyclophosphamide, vincristine and prednisone) with low-dose bleomycin (COP-Bleo). The study design emphasized histopathology review and systematic restaging to define complete remission (CR). Confirmed rates of CR for 443 evaluable patients were 59% for 286 patients receiving the CHOP regimens and 59% for 157 patients receiving COP-Bleo. Rates of CR were higher for patients with nodular lymphoma (69%) compared to those with diffuse lymphoma (54%) (p = 0.005). For patients with nodular lymphoma there was no difference in CR rates according to treatment. For patients with diffuse lymphomas the CR rate was higher with the CHOP programs (58%) than with COP-Bleo (44%) (p = 0.10). Overall duration of CR and survival was significantly longer for patients with nodular lymphoma compared to diffuse lymphoma (p less than 0.01). At this time, remission duration and survival were similar regardless of induction regimen used in patients with nodular lymphoma. However, in patients with diffuse lymphoma, the duration of CR and overall survival were improved by treatment with the CHOP regimens compared to COP-Bleo (p = 0.02). Thus, in this controlled study we have demonstrated that initial combination chemotherapy employing the CHOP regimen was a superior remission induction therapy for patients with diffuse lymphoma.