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Search Results: 1 - 10 of 6724 matches for " Tomá? Douda "
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Whipple’s Disease: Our Own Experience and Review of the Literature
Jan Bure?,Marcela Kopá?ová,Tomá? Douda,Jolana Bártová,Jan Tom,Stanislav Rejchrt,Ilja Tachecí
Gastroenterology Research and Practice , 2013, DOI: 10.1155/2013/478349
Abstract: Whipple’s disease is a chronic infectious systemic disease caused by the bacterium Tropheryma whipplei. Nondeforming arthritis is frequently an initial complaint. Gastrointestinal and general symptoms include marked diarrhoea (with serious malabsorption), abdominal pain, prominent weight loss, and low-grade fever. Possible neurologic symptoms (up to 20%) might be associated with worse prognosis. Diagnosis is based on the clinical picture and small intestinal histology revealing foamy macrophages containing periodic-acid-Schiff- (PAS-) positive material. Long-term (up to one year) antibiotic therapy provides a favourable outcome in the vast majority of cases. This paper provides review of the literature and an analysis of our 5 patients recorded within a 20-year period at a tertiary gastroenterology centre. Patients were treated using i.v. penicillin G or amoxicillin-clavulanic acid + i.v. gentamicin for two weeks, followed by p.o. doxycycline (100?mg per day) plus p.o. salazopyrine (3?g per day) for 1 year. Full remission was achieved in all our patients. 1. Introduction Whipple’s disease is a rare, chronic, and infectious systemic disease caused by the bacterium Tropheryma whipplei, a member of the diverse order of Actinomycetales, usually found in soil [1]. 2. History In 1907, George Hoyt Whipple described a case of a 36-year-old physician (medical missionary) [2]. Whipple published this report only two years after his graduation from the Johns Hopkins University in 1905. Subsequently he won the Nobel Prize in physiology and medicine (for his “discovery concerning liver therapy of anaemia” in 1934). Whipple described his case as “gradual loss of weight and strength, stools consisting chiefly of neutral fat and fatty acids, indefinite abdominal signs, and a peculiar multiple arthritis” [2]. The patient died of this progressive illness. Whipple called it intestinal lipodystrophy since he observed the accumulation of??“large masses of neutral fats and fatty acids in the lymph spaces.” The illness was renamed Whipple’s disease in 1949 [3]. An infectious aetiology was suspected as early as Whipple’s initial report. Whipple described a “number of rod-shaped organisms resembling in form the tubercle bacillus” in the vacuoles of the foamy cells [2]. Until the early 1960s, the disease was considered to be a uniformly fatal and untreatable primary disorder of fat metabolism. In 1952, the first successful treatment with antibiotics was reported (a prolonged period of chloramphenicol) [4]. Bacillary bodies were identified by transmission electron microscopy,
Evidence for a high mutation rate at rapidly evolving yeast centromeres
Douda Bensasson
BMC Evolutionary Biology , 2011, DOI: 10.1186/1471-2148-11-211
Abstract: Using DNA sequences of all 16 centromeres from 34 strains of Saccharomyces cerevisiae and population genomic data from Saccharomyces paradoxus, I show that centromeres in both species evolve 3 times more rapidly even than selectively unconstrained DNA. Exceptionally high levels of polymorphism seen in multiple yeast populations suggest that rapid centromere evolution does not result from the repeated selective sweeps expected under meiotic drive. I further show that there is little evidence for crossing-over or gene conversion within centromeres, although there is clear evidence for recombination in their immediate vicinity. Finally I show that the mutation spectrum at centromeres is consistent with the pattern of spontaneous mutation elsewhere in the genome.These results indicate that rapid centromere evolution is a common phenomenon in yeast species. Furthermore, these results suggest that rapid centromere evolution does not result from the mutagenic effect of gene conversion, but from a generalised increase in the mutation rate, perhaps arising from the unusual chromatin structure at centromeres in yeast and other eukaryotes.Centromeres form the points at which the spindle attaches to DNA to ensure its proper segregation during cell division. This function is conserved from yeast to humans, and yet centromeres evolve rapidly [1-8]. Indeed, some have proposed that rapid centromere evolution could drive speciation [1,6,8]. More specifically, Henikoff et al [1] propose that because centromeres and the genes encoding their associated proteins are essential and more rapidly evolving than other DNA, their divergence is more likely than other DNA to result in genetic incompatibilities in hybrids following reproductive isolation.Why would centromere sequences that are essential to proper chromosome segregation be evolving so fast? Most types of centromere are not defined by their DNA sequence [8], so a trivial explanation is that their rapid evolution is simply a consequ
NSAID-Induced Enteropathy in Rheumatoid Arthritis Patients with Chronic Occult Gastrointestinal Bleeding: A Prospective Capsule Endoscopy Study
Ilja Tachecí,Petr Bradna,Tomá? Douda,Drahomíra Ba?tecká,Marcela Kopá?ová,Stanislav Rejchrt,Jan Bure?
Gastroenterology Research and Practice , 2013, DOI: 10.1155/2013/268382
Abstract: Background. The purpose of study was to evaluate the diagnostic yield of capsule endoscopy for NSAID-induced enteropathy and clinical, laboratory, and endoscopic characteristics of disease in patients with rheumatoid arthritis. Methods. 37 rheumatoid arthritis patients (30 women; mean age 55) treated with NSAIDs (>1 month), presented with anaemia and/or positive faecal occult blood testing, entered the study and underwent capsule endoscopy (EndoCapsule; Olympus), laboratory tests, and filled in questionnaires. Results. The prevalence of NSAID-induced enteropathy diagnosed by capsule endoscopy was 68% (25/37), classified as mild (red spots or erosions) in 18 (49%), moderate (10–20 erosions) in 4 (11%), and severe enteropathy (>20 erosions or ulcers) in 3 (8%) patients. We did not find statistically significant relationship between the enteropathy and gender, age, haemoglobin, leukocytes, albumin and CRP, or dyspepsia. The difference between subgroups of NSAIDs according to the COX specificity was not statistically significant. Conclusions. Capsule endoscopy is a highly accurate noninvasive method for evaluation of NSAID-induced enteropathy. It was revealed in a substantial section of the patients with rheumatoid arthritis and occult gastrointestinal bleeding, mostly classified as mild damage. No simple clinical or laboratory markers of the presence or severity of NSAID-induced enteropathy were recognised. This trial is registered with DRKS00004940. 1. Introduction Non-steroidal anti-inflammatory drugs (NSAIDs) are some of the most frequently prescribed medications in clinical practice for their analgesic, antipyretic, and anti-inflammatory effects, especially in rheumatic and other musculoskeletal disorders. The adverse effects of NSAIDs therapy are well recognised and described especially in the gastroduodenal area [1, 2]; however, the prevalence of small intestinal structural or functional abnormalities induced by NSAIDs can be much higher. The first description of NSAID (aspirin)-induced gastropathy identified by endoscopy was presented by Douthwaite and Lintott in 1938 [3]. Small bowel damage due to indomethacin was observed for the first time in humans in the 70s [4]. The complete NSAIDs mechanism of action is not still fully understood, but it is at least partially based on an inhibition of cyclooxygenase (COX) [5]. The pathogenesis of enteropathy was initially thought to be associated with COX-1 inhibition only. However, it has been proven that selective COX-1 inhibition (or absence) does not lead to gastrointestinal lesions, and selective COX-2
Transition-Transversion Bias Is Not Universal: A Counter Example from Grasshopper Pseudogenes
Irene Keller ,Douda Bensasson,Richard A Nichols
PLOS Genetics , 2007, DOI: 10.1371/journal.pgen.0030022
Abstract: Comparisons of the DNA sequences of metazoa show an excess of transitional over transversional substitutions. Part of this bias is due to the relatively high rate of mutation of methylated cytosines to thymine. Postmutation processes also introduce a bias, particularly selection for codon-usage bias in coding regions. It is generally assumed, however, that there is a universal bias in favour of transitions over transversions, possibly as a result of the underlying chemistry of mutation. Surprisingly, this underlying trend has been evaluated only in two types of metazoan, namely Drosophila and the Mammalia. Here, we investigate a third group, and find no such bias. We characterize the point substitution spectrum in Podisma pedestris, a grasshopper species with a very large genome. The accumulation of mutations was surveyed in two pseudogene families, nuclear mitochondrial and ribosomal DNA sequences. The cytosine-guanine (CpG) dinucleotides exhibit the high transition frequencies expected of methylated sites. The transition rate at other cytosine residues is significantly lower. After accounting for this methylation effect, there is no significant difference between transition and transversion rates. These results contrast with reports from other taxa and lead us to reject the hypothesis of a universal transition/transversion bias. Instead we suggest fundamental interspecific differences in point substitution processes.
A new approach for improvement of fractal image encoding
Sofia Douda,,Abdelhakim El Imrani,,Abdallah Bagri
International Journal on Computer Science and Engineering , 2010,
Abstract: In this paper, we propose, in a first part, an approach to reduce the computational complexity of fractal image encoding by using the Shannon entropy (APENT). A speedup factor of 8 is obtained while image quality is still preserving. In a second part, we improve the APENT by using the AP2D approach that we have proposed in a previous study. We refer to this proposed approach as AP2D-ENT. The experimental results show that AP2D-ENT is effective in speeding up the encoding time without decreasing the image quality. Indeed, a speedup factor of 18 is reached for the test images with an increase of the compression ratio (CR) and a good image quality.
Evolutionary Genomics of Transposable Elements in Saccharomyces cerevisiae
Martin Carr, Douda Bensasson, Casey M. Bergman
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0050978
Abstract: Saccharomyces cerevisiae is one of the premier model systems for studying the genomics and evolution of transposable elements. The availability of the S. cerevisiae genome led to unprecedented insights into its five known transposable element families (the LTR retrotransposons Ty1-Ty5) in the years shortly after its completion. However, subsequent advances in bioinformatics tools for analysing transposable elements and the recent availability of genome sequences for multiple strains and species of yeast motivates new investigations into Ty evolution in S. cerevisiae. Here we provide a comprehensive phylogenetic and population genetic analysis of all Ty families in S. cerevisiae based on a systematic re-annotation of Ty elements in the S288c reference genome. We show that previous annotation efforts have underestimated the total copy number of Ty elements for all known families. In addition, we identify a new family of Ty3-like elements related to the S. paradoxus Ty3p which is composed entirely of degenerate solo LTRs. Phylogenetic analyses of LTR sequences identified three families with short-branch, recently active clades nested among long branch, inactive insertions (Ty1, Ty3, Ty4), one family with essentially all recently active elements (Ty2) and two families with only inactive elements (Ty3p and Ty5). Population genomic data from 38 additional strains of S. cerevisiae show that the majority of Ty insertions in the S288c reference genome are fixed in the species, with insertions in active clades being predominantly polymorphic and insertions in inactive clades being predominantly fixed. Finally, we use comparative genomic data to provide evidence that the Ty2 and Ty3p families have arisen in the S. cerevisiae genome by horizontal transfer. Our results demonstrate that the genome of a single individual contains important information about the state of TE population dynamics within a species and suggest that horizontal transfer may play an important role in shaping the genomic diversity of transposable elements in unicellular eukaryotes.
Cardiorespiratory Fitness, Metabolic Risk, and Inflammation in Children
Antonios D. Christodoulos,Helen T. Douda,Savvas P. Tokmakidis
International Journal of Pediatrics , 2012, DOI: 10.1155/2012/270515
Abstract: The aim of this study was to investigate the independent associations among cardiorespiratory fitness, metabolic syndrome (MetS), and C-reactive protein (CRP) in children. The sample consisted of 112 children (11.4  ±  0.4 years). Data was obtained for children’s anthropometry, cardiorespiratory fitness, MetS components, and CRP levels. MetS was defined using criteria analogous to the Adult Treatment Panel III definition. A MetS risk score was also computed. Prevalence of the MetS was 5.4%, without gender differences. Subjects with low fitness showed significantly higher MetS risk (<0.001) and CRP (<0.007), compared to the high-fitness pupils. However, differences in MetS risk, and CRP between fitness groups decreased when adjusted for waist circumference. These data indicate that the mechanisms linking cardiorespiratory fitness, MetS risk and inflammation in children are extensively affected by obesity. Intervention strategies aiming at reducing obesity and improving cardiorespiratory fitness in childhood might contribute to the prevention of the MetS in adulthood.
Cardiorespiratory Fitness, Metabolic Risk, and Inflammation in Children
Antonios D. Christodoulos,Helen T. Douda,Savvas P. Tokmakidis
International Journal of Pediatrics , 2012, DOI: 10.1155/2012/270515
Abstract: The aim of this study was to investigate the independent associations among cardiorespiratory fitness, metabolic syndrome (MetS), and C-reactive protein (CRP) in children. The sample consisted of 112 children (11.4??±??0.4 years). Data was obtained for children’s anthropometry, cardiorespiratory fitness, MetS components, and CRP levels. MetS was defined using criteria analogous to the Adult Treatment Panel III definition. A MetS risk score was also computed. Prevalence of the MetS was 5.4%, without gender differences. Subjects with low fitness showed significantly higher MetS risk ( ) and CRP ( ), compared to the high-fitness pupils. However, differences in MetS risk, and CRP between fitness groups decreased when adjusted for waist circumference. These data indicate that the mechanisms linking cardiorespiratory fitness, MetS risk and inflammation in children are extensively affected by obesity. Intervention strategies aiming at reducing obesity and improving cardiorespiratory fitness in childhood might contribute to the prevention of the MetS in adulthood. 1. Introduction The prevalence and severity of obesity is increasing dramatically among children and adolescents in many parts of the world, whereas prevalence rates are estimated to increase in the next decades [1]. In children, excess body fat appears to be strongly associated with the clustering of risk factors, such as hyperglycemia, dyslipidemia, and hypertension, which play a key role in the pathogenesis of the metabolic syndrome (MetS) [2]. Obesity and the MetS risk in children have been recently associated with systemic inflammatory markers, in particular C-reactive protein (CRP) [3, 4], implying that low-grade inflammation can already exist in childhood and may be a potential link between the obesity and the MetS. Among behavioral variables, cardiorespiratory fitness has a protective role in MetS and inflammatory factors; however, it is not entirely clear if the interrelations among cardiorespiratory fitness, MetS risk, and inflammation in children are independent or partly due to the mediating effect of obesity, since the existing data are limited and equivocal [5, 6]. Recent evidence indicates that the prevalence rates of childhood obesity in Greece remain high [1, 7] and often coexist with low cardiorespiratory fitness [8] and an unfavorable cardiometabolic risk profile [9]. For the Greek pediatric population these data suggest an increased cardiovascular morbidity in adulthood, given that high-risk children and adolescents are likely to become high-risk adults [10]. Although the
What’s Wrong with Requirements Specification? An Analysis of the Fundamental Failings of Conventional Thinking about Software Requirements, and Some Suggestions for Getting it Right  [PDF]
Tom Gilb
Journal of Software Engineering and Applications (JSEA) , 2010, DOI: 10.4236/jsea.2010.39096
Abstract: We know many of our IT projects fail and disappoint. The poor state of requirements methods and practice is frequently stated as a factor for IT project failure. In this paper, I discuss what I believe is the fundamental cause: we think like programmers, not engineers and managers. We do not concentrate on value delivery, but instead on functions, on use-cases and on code delivery. Further, management is not taking its responsibility to make things better. In this paper, ten practical key principles are proposed, which aim to improve the quality of requirements specification.
Internal Resource Audit for Strategists—A Proposal  [PDF]
Tom Connor
iBusiness (IB) , 2011, DOI: 10.4236/ib.2011.33038
Abstract: It is the purpose of this article to suggest a structured approach to internal resource audit, which, whilst of necessity general-purpose in design, would be capable of adaptation to particular company cases. Consequently this paper does not aim at theory development, but to make a conceptual contribution to the art and practice of management. It will, however, offer some criticism of current theory from a management perspective.
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