53 resultados para Population non clinique

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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PURPOSE To explore whether population-related pharmacogenomics contribute to differences in patient outcomes between clinical trials performed in Japan and the United States, given similar study designs, eligibility criteria, staging, and treatment regimens. METHODS We prospectively designed and conducted three phase III trials (Four-Arm Cooperative Study, LC00-03, and S0003) in advanced-stage, non-small-cell lung cancer, each with a common arm of paclitaxel plus carboplatin. Genomic DNA was collected from patients in LC00-03 and S0003 who received paclitaxel (225 mg/m(2)) and carboplatin (area under the concentration-time curve, 6). Genotypic variants of CYP3A4, CYP3A5, CYP2C8, NR1I2-206, ABCB1, ERCC1, and ERCC2 were analyzed by pyrosequencing or by PCR restriction fragment length polymorphism. Results were assessed by Cox model for survival and by logistic regression for response and toxicity. Results Clinical results were similar in the two Japanese trials, and were significantly different from the US trial, for survival, neutropenia, febrile neutropenia, and anemia. There was a significant difference between Japanese and US patients in genotypic distribution for CYP3A4*1B (P = .01), CYP3A5*3C (P = .03), ERCC1 118 (P < .0001), ERCC2 K751Q (P < .001), and CYP2C8 R139K (P = .01). Genotypic associations were observed between CYP3A4*1B for progression-free survival (hazard ratio [HR], 0.36; 95% CI, 0.14 to 0.94; P = .04) and ERCC2 K751Q for response (HR, 0.33; 95% CI, 0.13 to 0.83; P = .02). For grade 4 neutropenia, the HR for ABCB1 3425C-->T was 1.84 (95% CI, 0.77 to 4.48; P = .19). CONCLUSION Differences in allelic distribution for genes involved in paclitaxel disposition or DNA repair were observed between Japanese and US patients. In an exploratory analysis, genotype-related associations with patient outcomes were observed for CYP3A4*1B and ERCC2 K751Q. This common-arm approach facilitates the prospective study of population-related pharmacogenomics in which ethnic differences in antineoplastic drug disposition are anticipated.

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Cognitive-perceptive 'basic symptoms' are used complementary to ultra-high-risk criteria in order to predict onset of psychosis in the pre-psychotic phase. The aim was to investigate the prevalence of a broad selection of 'basic symptoms' in a representative general adolescent population sample (GPS; N=96) and to compare it with adolescents first admitted for early onset psychosis (EOP; N=87) or non-psychotic psychiatric disorders (NP; N=137).

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In children with structurally normal hearts, the mechanisms of arrhythmias are usually the same as in the adult patient. Some arrhythmias are particularly associated with young age and very rarely seen in adult patients. Arrhythmias in structural heart disease may be associated either with the underlying abnormality or result from surgical intervention. Chronic haemodynamic stress of congenital heart disease (CHD) might create an electrophysiological and anatomic substrate highly favourable for re-entrant arrhythmias. As a general rule, prescription of antiarrhythmic drugs requires a clear diagnosis with electrocardiographic documentation of a given arrhythmia. Risk-benefit analysis of drug therapy should be considered when facing an arrhythmia in a child. Prophylactic antiarrhythmic drug therapy is given only to protect the child from recurrent supraventricular tachycardia during this time span until the disease will eventually cease spontaneously. In the last decades, radiofrequency catheter ablation is progressively used as curative therapy for tachyarrhythmias in children and patients with or without CHD. Even in young children, procedures can be performed with high success rates and low complication rates as shown by several retrospective and prospective paediatric multi-centre studies. Three-dimensional mapping and non-fluoroscopic navigation techniques and enhanced catheter technology have further improved safety and efficacy even in CHD patients with complex arrhythmias. During last decades, cardiac devices (pacemakers and implantable cardiac defibrillator) have developed rapidly. The pacing generator size has diminished and the pacing leads have become progressively thinner. These developments have made application of cardiac pacing in children easier although no dedicated paediatric pacing systems exist.

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Acute non-specific abdominal pain (NSAP) is prevalent in 6-25% of the general population and is a common cause of admission to the emergency department (ED). Despite involvement of substantial financial and human resources, there are few data on long-term outcome after initial diagnosis. The aim of this study was to evaluate long-term outcome of patients initially admitted with NSAP to an ED.

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Learning by reinforcement is important in shaping animal behavior, and in particular in behavioral decision making. Such decision making is likely to involve the integration of many synaptic events in space and time. However, using a single reinforcement signal to modulate synaptic plasticity, as suggested in classical reinforcement learning algorithms, a twofold problem arises. Different synapses will have contributed differently to the behavioral decision, and even for one and the same synapse, releases at different times may have had different effects. Here we present a plasticity rule which solves this spatio-temporal credit assignment problem in a population of spiking neurons. The learning rule is spike-time dependent and maximizes the expected reward by following its stochastic gradient. Synaptic plasticity is modulated not only by the reward, but also by a population feedback signal. While this additional signal solves the spatial component of the problem, the temporal one is solved by means of synaptic eligibility traces. In contrast to temporal difference (TD) based approaches to reinforcement learning, our rule is explicit with regard to the assumed biophysical mechanisms. Neurotransmitter concentrations determine plasticity and learning occurs fully online. Further, it works even if the task to be learned is non-Markovian, i.e. when reinforcement is not determined by the current state of the system but may also depend on past events. The performance of the model is assessed by studying three non-Markovian tasks. In the first task, the reward is delayed beyond the last action with non-related stimuli and actions appearing in between. The second task involves an action sequence which is itself extended in time and reward is only delivered at the last action, as it is the case in any type of board-game. The third task is the inspection game that has been studied in neuroeconomics, where an inspector tries to prevent a worker from shirking. Applying our algorithm to this game yields a learning behavior which is consistent with behavioral data from humans and monkeys, revealing themselves properties of a mixed Nash equilibrium. The examples show that our neuronal implementation of reward based learning copes with delayed and stochastic reward delivery, and also with the learning of mixed strategies in two-opponent games.

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Learning by reinforcement is important in shaping animal behavior. But behavioral decision making is likely to involve the integration of many synaptic events in space and time. So in using a single reinforcement signal to modulate synaptic plasticity a twofold problem arises. Different synapses will have contributed differently to the behavioral decision and, even for one and the same synapse, releases at different times may have had different effects. Here we present a plasticity rule which solves this spatio-temporal credit assignment problem in a population of spiking neurons. The learning rule is spike time dependent and maximizes the expected reward by following its stochastic gradient. Synaptic plasticity is modulated not only by the reward but by a population feedback signal as well. While this additional signal solves the spatial component of the problem, the temporal one is solved by means of synaptic eligibility traces. In contrast to temporal difference based approaches to reinforcement learning, our rule is explicit with regard to the assumed biophysical mechanisms. Neurotransmitter concentrations determine plasticity and learning occurs fully online. Further, it works even if the task to be learned is non-Markovian, i.e. when reinforcement is not determined by the current state of the system but may also depend on past events. The performance of the model is assessed by studying three non-Markovian tasks. In the first task the reward is delayed beyond the last action with non-related stimuli and actions appearing in between. The second one involves an action sequence which is itself extended in time and reward is only delivered at the last action, as is the case in any type of board-game. The third is the inspection game that has been studied in neuroeconomics. It only has a mixed Nash equilibrium and exemplifies that the model also copes with stochastic reward delivery and the learning of mixed strategies.

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Non-perforating abomasal lesions are a considerable problem affecting more than half the population of veal calves. The objective of the present study was to assess the prevalence of pyloric and fundic abomasal lesions in Swiss veal calves at slaughter and to compare the occurrence of non-perforating abomasal lesions between two different production programs ('Naturafarm' and 'conventional'). 'Conventional'-production settings met the minimal standards as defined by the Swiss animal welfare legislation, whereas 'Naturafarm' production complied with increased animal welfare requirements. In order to identify risk factors for the development of abomasal lesions, information on management, housing, and feeding was obtained by a questionnaire. A total of 125 abomasa were randomly selected in one large abattoir. They were examined macroscopically, and the occurence of lesions in either the fundic or pyloric region of the abomasum was recorded separately. Animals raised in the 'conventional'-production setting revealed a significantly higher prevalence of lesions in the fundic part. Factors significantly affecting the prevalence of non-perforating lesions in the fundic part were the 'conventional'-production environment, including missing access to an outside pen, missing access to water and straw as the only roughage, feeding by bucket and the liquid milk by-product Protofit in combination with the powder Sprayfit.

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The clinical validity of at-risk criteria of psychosis had been questioned based on epidemiological studies that have reported much higher prevalence and annual incidence rates of psychotic-like experiences (PLEs as assessed by either self rating questionnaires or layperson interviews) in the general population than of the clinical phenotype of psychotic disorders (van Os et al., 2009). Thus, it is unclear whether “current at-risk criteria reflect behaviors so common among adolescents and young adults that a valid distinction between ill and non-ill persons is difficult” (Carpenter, 2009). We therefore assessed the 3-month prevalence of at-risk criteria by means of telephone interviews in a randomly drawn general population sample from the at-risk age segment (age 16–35 years) in the Canton Bern, Switzerland. Eighty-five of 102 subjects had valid phone numbers, 21 of these subjects refused (although 6 of them signaled willingness to participate at a later time), 4 could not be contacted. Sixty subjects (71% of the enrollment fraction) participated. Two participants met exclusion criteria (one for being psychotic, one for lack of language skills). Twenty-two at-risk symptoms were assessed for their prevalence and severity within the 3 months prior to the interview by trained clinical raters using (i) the Structured Interview for Prodromal Syndromes (SIPS; Miller et al., 2002) for the evaluation of 5 attenuated psychotic and 3 brief limited intermittent psychotic symptoms (APS, BLIPS) as well as state-trait criteria of the ultra-high-risk (UHR) criteria and (ii) the Schizophrenia Proneness Instrument, Adult version (SPI-A; Schultze-Lutter et al., 2007) for the evaluation of the 14 basic symptoms included in COPER and COGDIS (Schultze-Lutter et al., 2008). Further, psychiatric axis I diagnoses were assessed by means of the Mini-International Neuropsychiatric Interview, M.I.N.I. (Sheehan et al., 1998), and psychosocial functioning by the Scale of Occupational and Functional Assessment (SOFAS; APA, 1994). All interviewees felt ‘rather’ or ‘very’ comfortable with the interview. Of the 58 included subjects, only 1 (2%) fulfilled APS criteria by reporting the attenuated, non-delusional idea of his mind being literally read by others at a frequency of 2–3 times a week that had newly occurred 6 weeks ago. BLIPS, COPER, COGDIS or state-trait UHR criteria were not reported. Yet, twelve subjects (21%) described sub-threshold at-risk symptoms: 7 (12%) reported APS relevant symptoms but did not meet time/frequency criteria of APS, and 9 (16%) reported COPER and/or COGDIS relevant basic symptoms but at an insufficient frequency or as a trait lacking increase in severity; 4 of these 12 subjects reported both sub-threshold APS and sub-threshold basic symptoms. Table 1 displays type and frequency of the sub-threshold at-risk symptoms.

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Conservation strategies for long-lived vertebrates require accurate estimates of parameters relative to the populations' size, numbers of non-breeding individuals (the “cryptic” fraction of the population) and the age structure. Frequently, visual survey techniques are used to make these estimates but the accuracy of these approaches is questionable, mainly because of the existence of numerous potential biases. Here we compare data on population trends and age structure in a bearded vulture (Gypaetus barbatus) population from visual surveys performed at supplementary feeding stations with data derived from population matrix-modelling approximations. Our results suggest that visual surveys overestimate the number of immature (<2 years old) birds, whereas subadults (3–5 y.o.) and adults (>6 y.o.) were underestimated in comparison with the predictions of a population model using a stable-age distribution. In addition, we found that visual surveys did not provide conclusive information on true variations in the size of the focal population. Our results suggest that although long-term studies (i.e. population matrix modelling based on capture-recapture procedures) are a more time-consuming method, they provide more reliable and robust estimates of population parameters needed in designing and applying conservation strategies. The findings shown here are likely transferable to the management and conservation of other long-lived vertebrate populations that share similar life-history traits and ecological requirements.

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Atopic dermatitis in humans and dogs is a chronic relapsing allergic skin disease. Dogs show a spontaneous disease similar to the human counterpart and represent a model to improve our understanding of the immunological mechanisms, the pathogenesis of the disease, and new therapy development. The aim of the study was to determine the frequency and phenotype of dendritic cells (DC) in the epidermis and dermis of healthy, canine atopic dermatitis lesional, and non-allergic inflammatory skin to further validate the model and to obtain insights into the contribution of DC to the pathogenesis of skin diseases in dogs. We first characterized canine skin DC using flow-cytometric analysis of isolated skin DC combined with an immunohistochemical approach. A major population of canine skin dendritic cells was identified as CD1c(+)CD11c(+)CD14(-)CD80(+)MHCII(+)MAC387(-) cells, with dermal DC but not Langerhans cells expressing CD11b. In the epidermis of lesional canine atopic dermatitis and non-allergic inflammatory skin, we found significantly more dendritic cells compared with nonlesional and control skin. Only in canine atopic dermatitis skin did we find a subset of dendritic cells positive for IgE, in the epidermis and the dermis. Under all inflammatory conditions, dermal dendritic cells expressed more CD14 and CD206. MAC387(+) putative macrophages were absent in healthy but present in inflamed skin, in particular during non-allergic diseases. This study permits a phenotypic identification and differentiation of canine skin dendritic cells and has identified markers and changes in dendritic cells and macrophage populations related to allergic and non-allergic inflammatory conditions. Our data suggest the participation of dendritic cells in the pathogenesis of canine atopic dermatitis similar to human atopic dermatitis and further validate the only non-murine spontaneous animal model for this disease.

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Background Levels of differentiation among populations depend both on demographic and selective factors: genetic drift and local adaptation increase population differentiation, which is eroded by gene flow and balancing selection. We describe here the genomic distribution and the properties of genomic regions with unusually high and low levels of population differentiation in humans to assess the influence of selective and neutral processes on human genetic structure. Methods Individual SNPs of the Human Genome Diversity Panel (HGDP) showing significantly high or low levels of population differentiation were detected under a hierarchical-island model (HIM). A Hidden Markov Model allowed us to detect genomic regions or islands of high or low population differentiation. Results Under the HIM, only 1.5% of all SNPs are significant at the 1% level, but their genomic spatial distribution is significantly non-random. We find evidence that local adaptation shaped high-differentiation islands, as they are enriched for non-synonymous SNPs and overlap with previously identified candidate regions for positive selection. Moreover there is a negative relationship between the size of islands and recombination rate, which is stronger for islands overlapping with genes. Gene ontology analysis supports the role of diet as a major selective pressure in those highly differentiated islands. Low-differentiation islands are also enriched for non-synonymous SNPs, and contain an overly high proportion of genes belonging to the 'Oncogenesis' biological process. Conclusions Even though selection seems to be acting in shaping islands of high population differentiation, neutral demographic processes might have promoted the appearance of some genomic islands since i) as much as 20% of islands are in non-genic regions ii) these non-genic islands are on average two times shorter than genic islands, suggesting a more rapid erosion by recombination, and iii) most loci are strongly differentiated between Africans and non-Africans, a result consistent with known human demographic history.

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OBJECTIVES: In this population-based study, reference values were generated for renal length, and the heritability and factors associated with kidney length were assessed. METHODS: Anthropometric parameters and renal ultrasound measurements were assessed in randomly selected nuclear families of European ancestry (Switzerland). The adjusted narrow sense heritability of kidney size parameters was estimated by maximum likelihood assuming multivariate normality after power transformation. Gender-specific reference centiles were generated for renal length according to body height in the subset of non-diabetic non-obese participants with normal renal function. RESULTS: We included 374 men and 419 women (mean ± SD, age 47 ± 18 and 48 ± 17 years, BMI 26.2 ± 4 and 24.5 ± 5 kg/m(2), respectively) from 205 families. Renal length was 11.4 ± 0.8 cm in men and 10.7 ± 0.8 cm in women; there was no difference between right and left renal length. Body height, weight and estimated glomerular filtration rate (eGFR) were positively associated with renal length, kidney function negatively, age quadratically, whereas gender and hypertension were not. The adjusted heritability estimates of renal length and volume were 47.3 ± 8.5 % and 45.5 ± 8.8 %, respectively (P < 0.001). CONCLUSION: The significant heritability of renal length and volume highlights the familial aggregation of this trait, independently of age and body size. Population-based references for renal length provide a useful guide for clinicians. KEY POINTS: • Renal length and volume are heritable traits, independent of age and size. • Based on a European population, gender-specific reference values/percentiles are provided for renal length. • Renal length correlates positively with body length and weight. • There was no difference between right and left renal lengths in this study. • This negates general teaching that the left kidney is larger and longer.

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Conventional hepatitis B vaccines do not elicit adequate antibody production in 5-10% vaccinees. This trial tests the ability of a third-generation vaccine, containing PreS1 and PreS2 antigens in addition to the S antigen, to elicit seroprotective titres in documented non- and low-responders, compared with those to a conventional vaccine. In the primary population of non-responders (<10 IU/l anti-HBs antibodies after > or = 4 previous injections of conventional vaccine) an enhanced antibody response was seen to additional injections of the third-generation vaccine compared with a conventional vaccine (absolute difference 14.9%; P = 0.006). Enhanced antibody responses were also found in a population that included low responders.

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Infections with hepatitis C virus (HCV) and, possibly, hepatitis B virus (HBV) are associated with an increased risk of non-Hodgkin's lymphoma (NHL) in the general population, but little information is available on the relationship between hepatitis viruses and NHL among people with HIV (PHIV). We conducted a matched case-control study nested in the Swiss HIV Cohort Study (SHCS). Two hundred and ninety-eight NHL cases and 889 control subjects were matched by SHCS centre, gender, age group, CD4+ count at enrollment, and length of follow-up. Odds ratios (OR) and corresponding 95% confidence intervals (CI) were computed using logistic regression to evaluate the association between NHL and seropositivity for antibodies against HCV (anti-HCV) and hepatitis B core antigen (anti-HBc), and for hepatitis B surface antigen (HBsAg). Anti-HCV was not associated with increased NHL risk overall (OR = 1.05; 95% CI: 0.63-1.75), or in different strata of CD4+ count, age or gender. Only among men having sex with men was an association with anti-HCV found (OR = 2.37; 95% CI: 1.03-5.43). No relationships between NHL risk and anti-HBc or HBsAg emerged. Coinfection with HIV and HCV or HBV did not increase NHL risk compared to HIV alone in the SHCS.