997 resultados para Chromosome Instability


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The aim of this study was to evaluate the histopathological and immunohistochemical alterations induced by detrusor instability in the bladder of rabbits submitted to partial bladder outlet obstruction. Thirty male Norfolk rabbits were divided into 2 groups, a clinical control and a group with detrusor instability. Urine culture, cystometric study, histopathological and immunohistochemical analysis were performed in all animals prior to surgery (M1) and 4 weeks after-surgery (M2). Partial obstruction (G2) resulted in a 2.5 fold increment (p < 0.05) in bladder weight when compared to control (G1). Four weeks after surgery, 93% of animals in G2 developed cystitis. Partial obstruction resulted in detrusor instability at M2 and bladder capacity was significantly increased (p < 0.05) from M1 to M2. The incidence of mild to moderate mucosal and adventitious fibrosis at M2 was higher in G2 (p < 0.05) when compared to G1. Inflammatory reaction at M2 was statistically higher (p < 0.05) in G2. There was no difference in muscular hypertrophy between M1 and M2 in G1. However, 67% of G2 bladders showed a moderate to intense muscular hypertrophy at M2. Hyperplasia of the epithelium was also increased in G2 when M1 and M2 were compared (p < 0.05). Detrusor instability induced by partial bladder outlet obstruction caused significant histopathological and immunohistochemical alterations in the bladder of rabbits.

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Blood cell lymphocyte chromosomes from untreated (UT) and clinically-cured (CC) patients with paracoccidioidomycosis and from healthy (control) people (CO) were studied. The frequency of aneuploid cells in the UT patients was higher than in the CC and CO individuals. The frequency of metaphase cells with premature centromere division was significantly higher in the UT than in the CC and CO group. No structural aberration and no statistically significant difference in the frequency of polyploidy was observed in the three groups studied. Our findings are indicative of an aneugenic (aneuploidy-inducing) action of infection by Paracoccidioides brasiliensis.

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Time series analysis of a diatom-inferred drought record suggests that Holocene hydroclimate of the northern Rocky Mountains has been characterized by oscillation between two mean climate states. The dominant climate state was initiated at the onset of the Holocene (ca. 11 ka); under this climate state, drought was strongly cyclic, recurring at frequencies that are similar to twentieth century multidecadal phase changes of the Pacific Decadal Oscillation. This pattern remained consistent throughout much of the mid- Holocene, continuing until ca. 4.5 ka. After this time the mean climate state changed, and drought recurrence became unstable; periods of cyclic drought alternated with periods of less predictable drought. The timing of this shift in climate was coincident with widespread severe drought in the mid-continent of North America. Overall, the strongest periodicity in severe drought occurred during the mid-Holocene, when temperatures in the northern Rocky Mountains were warmer than today.

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Temporally-growing frontal meandering and occasional eddy-shedding is observed in the Brazil Current (BC) as it flows adjacent to the Brazilian Coast. No study of the dynamics of this phenomenon has been conducted to date in the region between 22 degrees S and 25 degrees S. Within this latitude range, the flow over the intermediate continental slope is marked by a current inversion at a depth that is associated with the Intermediate Western Boundary Current (IWBC). A time series analysis of 10-current-meter mooring data was used to describe a mean vertical profile for the BC-IWBC jet and a typical meander vertical structure. The latter was obtained by an empirical orthogonal function (EOF) analysis that showed a single mode explaining 82% of the total variance. This mode structure decayed sharply with depth, revealing that the meandering is much more vigorous within the BC domain than it is in the IWBC region. As the spectral analysis of the mode amplitude time series revealed no significant periods, we searched for dominant wavelengths. This search was done via a spatial EOF analysis on 51 thermal front patterns derived from digitized AVHRR images. Four modes were statistically significant at the 95% confidence level. Modes 3 and 4, which together explained 18% of the total variance, are associated with 266 and 338-km vorticity waves, respectively. With this new information derived from the data, the [Johns, W.E., 1988. One-dimensional baroclinically unstable waves on the Gulf Stream potential vorticity gradient near Cape Hatteras. Dyn. Atmos. Oceans 11, 323-350] one-dimensional quasi-geostrophic model was applied to the interpolated mean BC-IWBC jet. The results indicated that the BC system is indeed baroclinically unstable and that the wavelengths depicted in the thermal front analysis are associated with the most unstable waves produced by the model. Growth rates were about 0.06 (0.05) days(-1) for the 266-km (338-km) wave. Moreover, phase speeds for these waves were low compared to the surface BC velocity and may account for remarks in the literature about growing standing or stationary meanders off southeast Brazil. The theoretical vertical structure modes associated with these waves resembled very closely to the one obtained for the current-meter mooring EOF analysis. We interpret this agreement as a confirmation that baroclinic instability is an important mechanism in meander growth in the BC system. (C) 2008 Elsevier B.V. All rights reserved.

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Malignant triton tumor (MTT) is an aggressive peripheral nerve sheath tumor with rhabdomyoblastic differentiation. Less than 100 cases have been described, being mostly male children with type 1 neurofibromatosis. We report a 6-year-old female with MTT and no diagnostic criteria for neurofibromatosis type 1. Cytogenetic analysis showed a 46,X,-X[4]/46,XX[16] karyotype. She underwent a transfemoral amputation and chemotherapy and is free of disease 15 months after diagnosis. The few cytogenetic studies of MTT described in the literature have been inconclusive. Further cytogenetic analyses are needed to understand the role of chromosome X monosomy in the pathogenesis of this rare tumor. Pediatr Blood Cancer 2012; 59: 13201323. (C) 2012 Wiley Periodicals, Inc.