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The detonation of an (hypothetical) improvised nuclear device (IND) can generate atmospheric release of radioactive material in the form of particles and dust that ultimately contaminate the soil. In this study, the detonation of an IND in an urban area was simulated, and its effects on humans were determined. The risk of solid cancer development due to radiation was calculated by taking into account prompt radiation and whole-body exposure of individuals near the detonation site up to 10 km. The excess relative risk (ERR) of developing solid cancer was evaluated by using the mathematical relationships from the Radiation Effects Research Foundation (RERF) studies and those from the HotSpot code. The methodology consists of using output data obtained from simulations performed with the HotSpot health physics code plugging in such numbers into a specific given equation used by RERF to evaluate the resulting impact. Such a preliminary procedure is expected to facilitate the decision-making process significantly.

Abstract Background The karyotypes of Leptodactylus species usually consist of 22 bi-armed chromosomes, but morphological variations in some chromosomes and even differences in the 2n have been reported. To better understand the mechanisms responsible for these differences, eight species were analysed using classical and molecular cytogenetic techniques, including replication banding with BrdU incorporation. Results Distinct chromosome numbers were found: 2n = 22 in Leptodactylus chaquensis, L. labyrinthicus, L. pentadactylus, L. petersii, L. podicipinus, and L. rhodomystax; 2n = 20 in Leptodactylus sp. (aff. podicipinus); and 2n = 24 in L. marmoratus. Among the species with 2n = 22, only three had the same basic karyotype. Leptodactylus pentadactylus presented multiple translocations, L. petersii displayed chromosome morphological discrepancy, and L. podicipinus had four pairs of telocentric chromosomes. Replication banding was crucial for characterising this variability and for explaining the reduced 2n in Leptodactylus sp. (aff. podicipinus). Leptodactylus marmoratus had few chromosomes with a similar banding patterns to the 2n = 22 karyotypes. The majority of the species presented a single NOR-bearing pair, which was confirmed using Ag-impregnation and FISH with an rDNA probe. In general, the NOR-bearing chromosomes corresponded to chromosome 8, but NORs were found on chromosome 3 or 4 in some species. Leptodactylus marmoratus had NORs on chromosome pairs 6 and 8. The data from C-banding, fluorochrome staining, and FISH using the telomeric probe helped in characterising the repetitive sequences. Even though hybridisation did occur on the chromosome ends, telomere-like repetitive sequences outside of the telomere region were identified. Metaphase I cells from L. pentadactylus confirmed its complex karyotype constitution because 12 chromosomes appeared as ring-shaped chain in addition to five bivalents. Conclusions Species of Leptodactylus exhibited both major and minor karyotypic differences which were identified by classical and molecular cytogenetic techniques. Replication banding, which is a unique procedure that has been used to obtain longitudinal multiple band patterns in amphibian chromosomes, allowed us to outline the general mechanisms responsible for these karyotype differences. The findings also suggested that L. marmoratus, which was formerly included in the genus Adenomera, may have undergone great chromosomal repatterning.

Diffuse intrinsic pontine glioma is a pediatric oncologic disease with dismal prognosis and no effective treatment. Since 2007, our patients have been using valproic acid as prophylactic anticonvulsant. We have undertaken a retrospective study in order to evaluate the influence of valproate in the outcomes of children with this disease in our center. Patients were treated with weekly carboplatin and vincristine and received conformal radiotherapy, either concurrent or sequential. Event-free survival and overall survival of patients not treated with valproic acid were 6.5 and 7.8 months. Accelerated failure time model (a parametric multivariate regression test for time-to-failure data) showed a statistically significant superiority of the median event-free survival of treated patients (6.5 vs. 9.5 months in treated patients; HR 0.54-95 % CI 0.33-0.87; p < 0.05) and also of overall survival (7.8 vs. 13.4 months in treated patients; HR 0.60-95 % CI 0.37-0.98; p = 0.05).

Purpose: The treatment of pediatric patients with malignant brain tumors has evolved considerably in the past decades. However, results are still unsatisfactory for some patients. Valproate has been shown to positively affect the survival of adult glioblastoma patients. We have been giving prophylactic antiepileptic drugs to newly diagnosed children with brain tumors. Since then, we noted a trend towards a better survival from our patients. In order to study this, we performed a retrospective evaluation in our institution., Methods: Standard survival analysis was used, calculating survival until death by all causes or censoring. Comparisons were made by Cox's proportional hazards model regression., Results: Between 2000 and 2010, 94 patients were treated (12 with high-grade gliomas, 56 medulloblastomas, and 26 ependymomas); median and mean ages were 7.7 and 7.8 years. Median follow-up was 60 months (35 for treated and 109 for untreated patients). Of these, 47 received valproate 10-15 mg/kg/day every 8-12 h and 47 did not. Patients who received valproate had a median survival of 34 months, whereas the other group had a median survival of 24 months (hazard ratios = 0.99, 0.57-1.75, p = 0.99)., Conclusions: These results do not prove that valproate prophylactic treatment in pediatric patients with malignant brain tumors had an influence on their survival. However, our cohort showed an effect of higher size than the recent European Organization for Research and Treatment of Cancer trial analysis, even though not significant. Clinical trials with valproate in pediatric malignant brain tumors should be carefully planned, in order to detect a possible effect of this drug in survival.

Although substantial progress has been made in pediatric brain tumor management, patients with brainstem tumors and high-grade gliomas, as well as patients less than 3 years of age with high-risk malignant tumors, have a poorer prognosis. The authors have been treating these patients with radiotherapy and standard carboplatin and vincristine chemotherapy. Since January 2007 the authors have been using valproate as anticonvulsant for prophylaxis. The authors performed a retrospective cohort analysis of pediatric patients with high-risk brain tumors treated with chemotherapy, radiotherapy, and valproate prophylaxis, comparing this group with a historical control. The 2007-2008 group was comprised of 22 patients, 15 with brainstem tumors (7 diffuse intrinsic pontine glioma [DIPG], 3 focal, the remaining infiltrating with a solid portion), 4 with diencephalic tumors (2 thalamic), and 3 with supratentorial high-grade tumors (1 glioblastoma, 1 recurrent grade III ependymoma, 1 with gliomatosis). There were 15 patients alive (68%) after a mean follow-up time of 19 months. Survival function comparison by log rank test was highly significant (P = .004) with a hazard ratio of 0.31 (0.14-0.70). Radiological response showed 3 complete responses (14%), 8 partial responses (36%), 5 stable diseases (23%), and 5 progresssive diseases (23%). The authors hypothesize that valproate may have potentiated the antiangiogenic effect of vincristine, diminished expression of resistance to carboplatin, and sensitized tumor cells to radiotherapy. The authors suggest that clinical trials of carboplatin and vincristine associated with oral continuous low-dose valproate are indicated for pediatric patients with high-risk brain tumor.

Objectives: To estimate survival and evaluate prognostic factors of pediatric patients with central nervous system (CNS) tumors treated in a single center., Methods: Retrospective analysis of survival of 103 children with primary brain tumors diagnosed consecutively from January 2000 to December 2006. Cox regression was used for multivariate analysis of factors that affect overall survival to define possible prognostic factors., Results: Median and mean ages were 7.2 and 7.6 years. There was a male predominance (1.22:1). Most patients had medulloblastomas or primitive neuroectodermal tumors (PNET, 38%), or low-grade astrocytomas (18%). The anatomic site of most tumors was the cerebellum (49%) and the brain stem (21%). Five-year survival after diagnosis was 84% for low-grade astrocytomas and 51% for medulloblastomas and PNET. Prognostic factors for overall survival were histopathological type (high-grade astrocytomas and ependymomas; hazard ratio = 3.7 to 3.9), surgery (hazard ratio of 0.5 for completely resected tumors) and radiotherapy (hazard ratio of 0.5 for patients who underwent radiotherapy)., Conclusions: Overall survival of pediatric patients with brain tumors in this study was similar to that found in populations of the United States and Europe. The prognostic factors defined for overall survival are also similar to those published in previous studies.