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Affected Region (affected + region)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Parallel divide-and-conquer scheme for 2D Delaunay triangulation

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 12 2006
Min-Bin Chen
Abstract This work describes a parallel divide-and-conquer Delaunay triangulation scheme. This algorithm finds the affected zone, which covers the triangulation and may be modified when two sub-block triangulations are merged. Finding the affected zone can reduce the amount of data required to be transmitted between processors. The time complexity of the divide-and-conquer scheme remains O(n log n), and the affected region can be located in O(n) time steps, where n denotes the number of points. The code was implemented with C, FORTRAN and MPI, making it portable to many computer systems. Experimental results on an IBM SP2 show that a parallel efficiency of 44,95% for general distributions can be attained on a 16-node distributed memory system. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Increased glucose metabolism and ATP level in brain tissue of Huntington's disease transgenic mice

FEBS JOURNAL, Issue 19 2008
Judit Oláh
Huntington's disease (HD) is a progressive neurodegenerative disorder characterized by multifarious dysfunctional alterations including mitochondrial impairment. In the present study, the formation of inclusions caused by the mutation of huntingtin protein and its relationship with changes in energy metabolism and with pathological alterations were investigated both in transgenic and 3-nitropropionic acid-treated mouse models for HD. The HD and normal mice were characterized clinically; the affected brain regions were identified by immunohistochemistry and used for biochemical analysis of the ATP-producing systems in the cytosolic and the mitochondrial compartments. In both HD models, the activities of some glycolytic enzymes were somewhat higher. By contrast, the activity of glyceraldehyde-3-phosphate dehydrogenase was much lower in the affected region of the brain compared to that of the control. Paradoxically, at the system level, glucose conversion into lactate was enhanced in cytosolic extracts from the HD brain tissue, and the level of ATP was higher in the tissue itself. The paradox could be resolved by taking all the observed changes in glycolytic enzymes into account, ensuing an experiment-based detailed mathematical model of the glycolytic pathway. The mathematical modelling using the experimentally determined kinetic parameters of the individual enzymes and the well-established rate equations predicted the measured flux and concentrations in the case of the control. The same mathematical model with the experimentally determined altered Vmax values of the enzymes did account for an increase of glycolytic flux in the HD sample, although the extent of the increase was not predicted quantitatively. This suggested a somewhat altered regulation of this major metabolic pathway in HD tissue. We then used the mathematical model to develop a hypothesis for a new regulatory interaction that might account for the observed changes; in HD, glyceraldehyde-3-phosphate dehydrogenase may be in closer proximity (perhaps because of the binding of glyceraldehyde-3-phosphate dehydrogenase to huntingtin) with aldolase and engage in channelling for glyceraldehyde-3-phosphate. By contrast to most of the speculation in the literature, our results suggest that the neuronal damage in HD tissue may be associated with increased energy metabolism at the tissue level leading to modified levels of various intermediary metabolites with pathological consequences. [source]

Histologic features of melanocytic nevi seen in association with mycosis fungoides

JOURNAL OF CUTANEOUS PATHOLOGY, Issue 10 2003
Jennifer M. McNiff
Background:, Many different tumors have been reported to occur simultaneously as collision lesions. To date, no such events have been reported between mycosis fungoides (MFs) and melanocytic neoplasms. Methods:, Two cases are presented in which patches of MF were superimposed on melanocytic nevi. In addition, 967 biopsies of MF from 411 patients were identified in an 8-year retrospective database search. Patient pathology history summaries were reviewed to identify inflamed nevi, atypical nevi, and melanoma submitted for histologic evaluation from this population. Results:, The occurrence of MF in a congenital nevus was associated with a halo phenomenon restricted to the affected region of the nevus in one patient. In the other patient, nests of two morphologies (lymphocytic and melanocytic) in the same biopsy presented a potentially confusing histologic picture. No other cases of MF superimposed on a nevus were identified in 967 biopsies from 411 patients with a histological diagnosis of MF seen over the past 8 years. In this population, 57 biopsies of melanocytic lesions were identified from 28 patients, including three atypical nevi and three melanomas. Conclusions:, The presence of MF superimposed on a nevus is rare and may lead to confounding histologic features or the development of a halo nevus phenomenon. [source]

Phlebosclerotic colitis coincident with carcinoma in adenoma

PATHOLOGY INTERNATIONAL, Issue 10 2003
Yasuhiko Kimura
Phlebosclerosis of the colon is a rare disease characterized by a thickening of the wall of the colon with fibrosis, hy-alinization and calcification to the affected veins. These symptoms result in a type of ischemic colitis known as phlebosclerotic colitis. A case of phlebosclerotic colitis coincident with carcinoma in adenoma is reported. A 74-year-old Japanese woman was admitted to hospital because of a mass in her right lower abdomen. Abdominal computed tomography examination revealed linear calcifications in the wall of the cecum and the ascending colon. Colonoscopy revealed dark purple mucosa with multiple ulcers in the cecum and the ascending colon. Biopsy specimens showed a marked hyalinous thickening of the wall of small blood vessels in the mucosa. Phlebosclerotic colitis was suspected because of negative results with amyloid stain. Alternative ileocolic angiography showed the serpentine of the peripheral nature blood vessels and pooling at the late venous phase. Microscopic examination of the surgically resected colon revealed mucosal and submucosal fibrosis, and a thickening of the venous wall with fibrosis, hyalinization and calcification from the mucosa to the serosa, which caused a marked luminal narrowing. A small polypoid lesion was also found in the affected region and was diagnosed histologically as carcinoma in adenoma. To our knowledge, this is the first reported case of phlebosclerotic colitis complicated by carcinoma. [source]