992 resultados para 438


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The objective of this study was to determine the effect of wearing a mouthguard on maximal exercise capacity and cardiopulmonary parameters at peak workload, and to assess the athletes' attitudes toward wearing a mouthguard. Thirteen volunteer male athletes (18 to 27 years old) were interviewed before and after delivery of a custom-made laminated mouthguard. A visual analogue scale (VAS, 0 - 100 mm) was used for judgment of interference with breathing, speaking, concentration and athletic performance. In addition, the athletes were subjected to a cardiorespiratory examination on a cycle ergometer with and without mouthguards. Subjectively, the athletes rated the mean interference with performance to be 37 mm VAS at the beginning of the study. Mean scores of impairment decreased to 23 mm VAS (p = 0.081) after wearing the mouthguard for four weeks, and further improved to 12 mm VAS (p < 0.001) after the test on the cycle ergometer. Objectively, the maximum workload during spiroergometry was even slightly elevated during exercise with the mouthguard (330.2 W) compared to exercise without the mouthguard (314.5 W). Peak minute ventilation and oxygen uptake were not different during exercise with and without the mouthguard. The present study demonstrated that a custom-made mouthguard does not significantly affect or reduce maximum exercise performance of athletes.

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PURPOSE: To prospectively determine quantitatively and qualitatively the timing of maximal enhancement of the normal small-bowel wall by using contrast material-enhanced multi-detector row computed tomography (CT). MATERIALS AND METHODS: This HIPAA-compliant study was approved by the institutional review board. After information on radiation risk was given, written informed consent was obtained from 25 participants with no history of small-bowel disease (mean age, 58 years; 19 men) who had undergone single-level dynamic CT. Thirty seconds after the intravenous administration of contrast material, a serial dynamic acquisition, consisting of 10 images obtained 5 seconds apart, was performed. Enhancement measurements were obtained over time from the small-bowel wall and the aorta. Three independent readers qualitatively assessed small-bowel conspicuity. Quantitative and qualitative data were analyzed during the arterial phase, the enteric phase (which represented peak small-bowel mural enhancement), and the venous phase. Statistical analysis included paired Student t test and Wilcoxon signed rank test with Bonferroni correction. A P value less than .05 was used to indicate a significant difference. RESULTS: The mean time to peak enhancement of the small-bowel wall was 49.3 seconds +/- 7.7 (standard deviation) and 13.5 seconds +/- 7.6 after peak aortic enhancement. Enhancement values were highest during the enteric phase (P < .05). Regarding small-bowel conspicuity, images obtained during the enteric phase were most preferred qualitatively; there was a significant difference between the enteric and arterial phases (P < .001) but not between the enteric and venous phases (P = .18). CONCLUSION: At multi-detector row CT, peak mural enhancement of the normal small bowel occurs on average about 50 seconds after intravenous administration of contrast material or 14 seconds after peak aortic enhancement.

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Background: We aimed to assess quality of life (QOL) and its predictors in stroke survivors after local intra-arterial thrombolysis (IAT) as well as to measure QOL according to the site of pretreatment vessel occlusion. Methods: From January 2000 to April 2004, 175 consecutive patients underwent IAT for acute ischemic stroke. Clinical and radiological data were collected prospectively. We contacted 135 stroke survivors after a mean of 923 (+/-431) days, 132 responded. QOL, assessed with EuroQol (EQ-5D), and functional abilities, measured with the modified Rankin Scale (mRS) and the Barthel Index, were compared, and predictors of QOL were analyzed. Results: Measured with EQ-5D, 56% of the patients reported a good QOL (EQ-5D Index >/=70). Low mRS and high Barthel Index scores at follow-up were associated with better overall QOL (Kendall's tau >0.5). Nevertheless, 25% of the functionally independent patients (mRS 0-2) indicated a markedly impaired QOL (EQ-5D Index <70) and 10% of disabled patients indicated good QOL. QOL was significantly lower in patients with occlusion of the internal carotid artery compared to patients with occlusion of the basilar artery or the M1, M2 or M3/4 segment of the middle cerebral artery (EQ-5D Index: p = 0.005). A high National Institute of Health Stroke Scale score on admission and occlusion of the internal carotid artery were independent predictors of impaired QOL (p < 0.05). Conclusion: More than half of the stroke survivors treated with IAT reported a good QOL, mostly survivors with mild disabilities. QOL assessment gives information that is not provided by traditional outcome scores. Our results support guidelines to measure QOL in stroke research. Copyright (c) 2008 S. Karger AG, Basel.

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BACKGROUND: HIV-1 infected individuals have an increased cardiovascular risk which is partially mediated by dyslipidemia. Single nucleotide polymorphisms in multiple genes involved in lipid transport and metabolism are presumed to modulate the risk of dyslipidemia in response to antiretroviral therapy. METHODS: The contribution to dyslipidemia of 20 selected single nucleotide polymorphisms of 13 genes reported in the literature to be associated with plasma lipid levels (ABCA1, ADRB2, APOA5, APOC3, APOE, CETP, LIPC, LIPG, LPL, MDR1, MTP, SCARB1, and TNF) was assessed by longitudinally modeling more than 4400 plasma lipid determinations in 438 antiretroviral therapy-treated participants during a median period of 4.8 years. An exploratory genetic score was tested that takes into account the cumulative contribution of multiple gene variants to plasma lipids. RESULTS: Variants of ABCA1, APOA5, APOC3, APOE, and CETP contributed to plasma triglyceride levels, particularly in the setting of ritonavir-containing antiretroviral therapy. Variants of APOA5 and CETP contributed to high-density lipoprotein-cholesterol levels. Variants of CETP and LIPG contributed to non-high-density lipoprotein-cholesterol levels, a finding not reported previously. Sustained hypertriglyceridemia and low high-density lipoprotein-cholesterol during the study period was significantly associated with the genetic score. CONCLUSIONS: Single nucleotide polymorphisms of ABCA1, APOA5, APOC3, APOE, and CETP contribute to plasma triglyceride and high-density lipoprotein-cholesterol levels during antiretroviral therapy exposure. Genetic profiling may contribute to the identification of patients at risk for antiretroviral therapy-related dyslipidemia.

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MicroRNAs (miRNAs) are an abundant class of non-coding RNAs that are believed to be important in many biological processes through regulation of gene expression. The precise molecular function of miRNAs in mammals is largely unknown and a better understanding will require loss-of-function studies in vivo. Here we show that a novel class of chemically engineered oligonucleotides, termed 'antagomirs', are efficient and specific silencers of endogenous miRNAs in mice. Intravenous administration of antagomirs against miR-16, miR-122, miR-192 and miR-194 resulted in a marked reduction of corresponding miRNA levels in liver, lung, kidney, heart, intestine, fat, skin, bone marrow, muscle, ovaries and adrenals. The silencing of endogenous miRNAs by this novel method is specific, efficient and long-lasting. The biological significance of silencing miRNAs with the use of antagomirs was studied for miR-122, an abundant liver-specific miRNA. Gene expression and bioinformatic analysis of messenger RNA from antagomir-treated animals revealed that the 3' untranslated regions of upregulated genes are strongly enriched in miR-122 recognition motifs, whereas downregulated genes are depleted in these motifs. Analysis of the functional annotation of downregulated genes specifically predicted that cholesterol biosynthesis genes would be affected by miR-122, and plasma cholesterol measurements showed reduced levels in antagomir-122-treated mice. Our findings show that antagomirs are powerful tools to silence specific miRNAs in vivo and may represent a therapeutic strategy for silencing miRNAs in disease.

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Asthma is an increasing health problem worldwide, but the long-term temporal pattern of clinical symptoms is not understood and predicting asthma episodes is not generally possible. We analyse the time series of peak expiratory flows, a standard measurement of airway function that has been assessed twice daily in a large asthmatic population during a long-term crossover clinical trial. Here we introduce an approach to predict the risk of worsening airflow obstruction by calculating the conditional probability that, given the current airway condition, a severe obstruction will occur within 30 days. We find that, compared with a placebo, a regular long-acting bronchodilator (salmeterol) that is widely used to improve asthma control decreases the risk of airway obstruction. Unexpectedly, however, a regular short-acting beta2-agonist bronchodilator (albuterol) increases this risk. Furthermore, we find that the time series of peak expiratory flows show long-range correlations that change significantly with disease severity, approaching a random process with increased variability in the most severe cases. Using a nonlinear stochastic model, we show that both the increased variability and the loss of correlations augment the risk of unstable airway function. The characterization of fluctuations in airway function provides a quantitative basis for objective risk prediction of asthma episodes and for evaluating the effectiveness of therapy.