995 resultados para pre-oxidation


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Different outcomes of the effect of catechin-caffeine mixtures and caffeine-only supplementation on energy expenditure and fat oxidation have been reported in short-term studies. Therefore, a meta-analysis was conducted to elucidate whether catechin-caffeine mixtures and caffeine-only supplementation indeed increase thermogenesis and fat oxidation. First, English-language studies measuring daily energy expenditure and fat oxidation by means of respiration chambers after catechin-caffeine mixtures and caffeine-only supplementation were identified through PubMed. Six articles encompassing a total of 18 different conditions fitted the inclusion criteria. Second, results were aggregated using random/mixed-effects models and expressed in terms of the mean difference in 24 h energy expenditure and fat oxidation between the treatment and placebo conditions. Finally, the influence of moderators such as BMI and dosage on the results was examined as well. The catechin-caffeine mixtures and caffeine-only supplementation increased energy expenditure significantly over 24 h (428.0 kJ (4.7%); P < 0.001 and 429.1 kJ (4.8%); P < 0.001, respectively). However, 24 h fat oxidation was only increased by catechin-caffeine mixtures (12.2 g (16.0%); P < 0.02 and 9.5 g (12.4%); P = 0.11, respectively). A dose-response effect on 24 h energy expenditure and fat oxidation occurred with a mean increase of 0.53 kJ mg(-1) (P < 0.01) and 0.02 g mg(-1) (P < 0.05) for catechin-caffeine mixtures and 0.44 kJ mg(-1) (P < 0.001) and 0.01 g mg(-1) (P < 0.05) for caffeine-only. In conclusion, catechin-caffeine mixtures or a caffeine-only supplementation stimulates daily energy expenditure dose-dependently by 0.4-0.5 kJ mg(-1) administered. Compared with placebo, daily fat-oxidation was only significantly increased after catechin-caffeine mixtures ingestion.

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Aim: The aim of the study was to investigate the influence of dietary intake of commercial hydrolyzed collagen (Gelatine Royal ®) on bone remodeling in pre-pubertal children. Methods: A randomized double-blind study was carried out in 60 children (9.42 ± 1.31 years) divided into three groups according to the amount of partially hydrolyzed collagen taken daily for 4 months: placebo (G-I, n = 18), collagen (G-II, n = 20) and collagen + calcium (G-III, n = 22) groups. Analyses of the following biochemical markers were carried out: total and bone alkaline phosphatase (tALP and bALP), osteocalcin, tartrate-resistant acid phosphatase (TRAP), type I collagen carboxy terminal telopeptide, lipids, calcium, 25-hydroxyvitamin D, insulin-like growth factor 1 (IGF-1), thyroid-stimulating hormone, free thyroxin and intact parathormone. Results: There was a significantly greater increase in serum IGF-1 in G-III than in G II (p < 0.01) or G-I (p < 0.05) during the study period, and a significantly greater increase in plasma tALP in G-III than in G-I (p < 0.05). Serum bALP behavior significantly (p < 0.05) differed between G-II (increase) and G-I (decrease). Plasma TRAP behavior significantly differed between G-II and G-I (p < 0.01) and between G-III and G-II (p < 0.05). Conclusion: Daily dietary intake of hydrolyzed collagen seems to have a potential role in enhancing bone remodeling at key stages of growth and development.

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OBJECTIVE: To determine the influence of body weight, fat mass, and fat distribution on resting endogenous glucose production in healthy lean and overweight individuals. DESIGN: measurements were performed in the resting postabsorptive state in individuals receiving an unrestricted diet. SETTING: Institute of Physiology of Lausanne University. MEASUREMENTS: resting post absorptive glucose production, glycogenolysis and gluconeogenesis; resting energy expenditure and net substrate oxidation. RESULTS: Endogenous glucose production was positively correlated with body weight, lean body mass, energy expenditure and carbohydrate oxidation. Gluconeogenesis was positively correlated with net lipid oxidation and energy expenditure, and negatively correlated with net carbohydrate oxidation. No correlation with body fat or fat distribution was observed. CONCLUSIONS: Gluconeogenesis shows a large interindividual variability. Net lipid oxidation and not body fat appears to be a major determinant of gluconeogenesis.

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Background: Mortality from invasive meningococcal disease (IMD) has remained stable over the last thirty years and it is unclear whether pre-hospital antibiotherapy actually produces a decrease in this mortality. Our aim was to examine whether pre-hospital oral antibiotherapy reduces mortality from IMD, adjusting for indication bias. Methods: A retrospective analysis was made of clinical reports of all patients (n = 848) diagnosed with IMD from 1995 to 2000 in Andalusia and the Canary Islands, Spain, and of the relationship between the use of pre-hospital oral antibiotherapy and mortality. Indication bias was controlled for by the propensity score technique, and a multivariate analysis was performed to determine the probability of each patient receiving antibiotics, according to the symptoms identified before admission. Data on in-hospital death, use of antibiotics and demographic variables were collected. A logistic regression analysis was then carried out, using death as the dependent variable, and prehospital antibiotic use, age, time from onset of symptoms to parenteral antibiotics and the propensity score as independent variables. Results: Data were recorded on 848 patients, 49 (5.72%) of whom died. Of the total number of patients, 226 had received oral antibiotics before admission, mainly betalactams during the previous 48 hours. After adjusting the association between the use of antibiotics and death for age, time between onset of symptoms and in-hospital antibiotic treatment, pre-hospital oral antibiotherapy remained a significant protective factor (Odds Ratio for death 0.37, 95% confidence interval 0.15–0.93). Conclusion: Pre-hospital oral antibiotherapy appears to reduce IMD mortality.

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The European Prospective Investigation into Cancer and nutrition (EPIC) is a long-term, multi-centric prospective study in Europe investigating the relationships between cancer and nutrition. This study has served as a basis for a number of Genome-Wide Association Studies (GWAS) and other types of genetic analyses. Over a period of 5 years, 52,256 EPIC DNA samples have been extracted using an automated DNA extraction platform. Here we have evaluated the pre-analytical factors affecting DNA yield, including anthropometric, epidemiological and technical factors such as center of subject recruitment, age, gender, body-mass index, disease case or control status, tobacco consumption, number of aliquots of buffy coat used for DNA extraction, extraction machine or procedure, DNA quantification method, degree of haemolysis and variations in the timing of sample processing. We show that the largest significant variations in DNA yield were observed with degree of haemolysis and with center of subject recruitment. Age, gender, body-mass index, cancer case or control status and tobacco consumption also significantly impacted DNA yield. Feedback from laboratories which have analyzed DNA with different SNP genotyping technologies demonstrate that the vast majority of samples (approximately 88%) performed adequately in different types of assays. To our knowledge this study is the largest to date to evaluate the sources of pre-analytical variations in DNA extracted from peripheral leucocytes. The results provide a strong evidence-based rationale for standardized recommendations on blood collection and processing protocols for large-scale genetic studies.

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The addition of a capped mini-exon [spliced leader (SL)] through trans-splicing is essential for the maturation of RNA polymerase (pol) II-transcribed polycistronic pre-mRNAs in all members of the Trypanosomatidae family. This process is an inter-molecular splicing reaction that follows the same basic rules of cis-splicing reactions. In this study, we demonstrated that mini-exons were added to precursor ribosomal RNA (pre-rRNA) are transcribed by RNA pol I, including the 5' external transcribed spacer (ETS) region. Additionally, we detected the SL-5'ETS molecule using three distinct methods and located the acceptor site between two known 5'ETS rRNA processing sites (A' and A1) in four different trypanosomatids. Moreover, we detected a polyadenylated 5'ETS upstream of the trans-splicing acceptor site, which also occurs in pre-mRNA trans-splicing. After treatment with an indirect trans-splicing inhibitor (sinefungin), we observed SL-5'ETS decay. However, treatment with 5-fluorouracil (a precursor of RNA synthesis that inhibits the degradation of pre-rRNA) led to the accumulation of SL-5'ETS, suggesting that the molecule may play a role in rRNA degradation. The detection of trans-splicing in these molecules may indicate broad RNA-joining properties, regardless of the polymerase used for transcription.

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Trypanosomatidae is a family of early branching eukaryotes harbouring a distinctive repertoire of gene expression strategies. Functional mature messenger RNA is generated via the trans-splicing and polyadenylation processing of constitutively transcribed polycistronic units. Recently, trans-splicing of pre-small subunit ribosomal RNA in the 5' external transcribed spacer region and of precursor tRNAsec have been described. Here, we used a previously validated semi-nested reverse transcription-polymerase chain reaction strategy to investigate internal transcribed spacer (ITS) I acceptor sites in total RNA from Leishmania (Leishmania) amazonensis. Two distinct spliced leader-containing RNAs were detected indicating that trans-splicing reactions occur at two AG acceptor sites mapped in this ITS region. These data provide further evidence of the wide spectrum of RNA molecules that act as trans-splicing acceptors in trypanosomatids.

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Summary Polyhydroxyalkanoates (PHAs) represent a family of polyesters naturally synthesized by a wide variety of bacteria. Through their thermoplastic and elastomeric qualities, together with their biodegradable and renewable properties, they are predicted to be a good alternative to the petroleum- derived plastics. Nevertheless, as PHA production costs using bacteria fermentation are still too high, PHA synthesis within eukaryotic systems, such as plants, has been elaborated. Although the costs were then efficiently lowered, the yield of PHAs produced remained low. In this study, Saccharomyces cerevisae has been used as another eukaryotic model in order to reveal the steps which limit PHA production. These cells express the PHA synthase of Pseudomonas aeruginosa and the PHAs obtained were analyzed to understand the flux of fatty acids towards and through the peroxisomal β-oxidation core cycle, generating the main substrate of the PHA synthase. When S. cerevisiae wild-type cells are grown in a media containing glucose as carbon source as well as fatty acids, the PHA monomer composition is largely influenced by the nature of the external fatty acid used. Thus, even-chain PHA monomers are generated from oleic acid (18:1Δ9cis) and odd- chain PHA monomers are generated from heptadecenoic acid (17:1Δ. 10 cis). Moreover, PHA synthesis is dependent on the first two enzymes of the 0-oxidation core cycle, the acyl-CoA oxidase and the multifunctional enzyme enoyl-CoA hydratase II / R-3-hydroxyacyl-CoA dehydrogenase. S. cerevisiae mutant cells growing on oleic or heptadecenoic acid and deficient in either the R-3- hydroxyacyl-CoA dehydrogenase or in the 3-ketothiolase activity, the last β-oxidation cycle steps, surprisingly contained PHAs of predominantly even-chain monomers. This is also noticed in wild- type and mutants grown on glucose or raffinose, indicating that the substrate used for PHA synthesis is generated from the degradation of intracellular short- and medium-chain fatty acids by the 3- oxidation cycle. Inhibition of fatty acid biosynthesis by cerulenin blocks the synthesis of PHAs from intracellular fatty acids but still enables the use of extracellular fatty acids for polymer production. Together, these results uncovered the existence of a substantial futile cycle whereby short- and medium-chain intermediates of the cytoplasmic fatty acid biosynthetic pathway are directed towards the peroxisomal β-oxidation pathway. In this thesis, no increase of the yield of PHA produced could be obtained. But the PHA synthesis confirmed the carbon flux into and through the β-oxidation core cycle and unveiled the existence of novel mechanisms. It is thus a good tool to study in vivo the flux of carbons in S. cerevisiae cells. Résumé Les polyhydroxyalkanoates (PHAs) sont une famille de polyesters naturellement synthétisés par un grand nombre de bactéries. Ayant des propriétés de thermoplastiques, d'élastomères et étant des ressources biodégradables et renouvelables, les PHAs représentent une bonne alternative aux plastiques dérivés du pétrole. Pour pallier aux coûts considérables de la production de PHAs par fermentation bactérienne, la synthèse de PHAs par des systèmes eucaryotes telles les plantes a été élaborée. Les coûts ont ainsi efficacement été diminués, mais le rendement de PHAs produits reste faible. Dans cette étude, Saccharomyces cerevisiae a été utilisé comme autre modèle eucaryote pour révéler les étapes limitantes de la production de PHAs. Les PHAs obtenus dans les cellules exprimant la F'HA synthase de Pseudomonas aeruginosa ont été analysés afin de comprendre le flux d'acides gras vers et à travers le cycle péroxisomal de la β-oxidation, principal producteur du substrat de la PHA synthase. Lorsque la souche S. cerevisiae de type sauvage se développe dans un milieu contenant du glucose et des acides gras, la composition des monomères de PHAs est influencée par la nature des acides gras extracellulaires. Ainsi, les monomères pairs sont générés par l'acide oléique (18:1Δ9cis), tandis que les impairs le sont par l'acide heptadécénoïque (17:1Δ10cis). La synthèse de PHAs est dépendante des deux premières enzymes de la β-oxidation; l'acyl-CoA oxidase et l'enzyme multifonctionnelle enoyl-CoA hydratase II / R-3-hydroxyacyl-CoA déshydrogénase. Les souches mutantes ne possédant pas les activités de la R-3-hydroxyacyl-CoA déshydrogénase ou de la 3- ketothiolase contiennent, en présence d'acide oléique ou heptadécénoïque, des PHAs composés essentiellement de monomères pairs. Cela a également été observé en présence de glucose ou de raffinose uniquement. Le substrat utilisé pour la synthèse de PHAs a ainsi été généré par la dégradation d'acides gras intracellulaires à chaîne courte et moyenne via le cycle de la β-oxidation. L'inhibition de la synthèse d'acides gras par la cérulénine a bloqué la synthèse de PHAs par les acides gras internes. Ces résultats ont révélés l'existence d'un cycle futile par lequel des intermédiaires à chaîne courte et moyenne de la synthèse cytoplasmique d'acides gras sont dirigés vers le cycle péroxisomal de la β-oxidation. Dans cette étude, le rendement de PHAs produits reste inchangé, mais l'analyse des PHAs permet de confirmer le flux de carbones vers et à travers le cycle péroxisomal de la β-oxidation et l'existence de nouveaux méchanismes a été dévoilée. Cette synthèse s'avère être un bon outil pour étudier in vivo le flux de carbones dans les cellules de S. cerevisiae.

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This review investigates ancient infectious diseases in the Americas dated to the pre-colonial period and considers what these findings can tell us about the history of the indigenous peoples of the Americas. It gives an overview, but focuses on four microbial pathogens from this period: Helicobacter pylori, Mycobacterium tuberculosis, Trypanosoma cruzi and Coccidioides immitis, which cause stomach ulceration and gastric cancer, tuberculosis, Chagas disease and valley fever, respectively. These pathogens were selected as H. pylori can give insight into ancient human migrations into the Americas, M. tuberculosis is associated with population density and urban development, T. cruzi can elucidate human living conditions and C. immitis can indicate agricultural development. A range of methods are used to diagnose infectious disease in ancient human remains, with DNA analysis by polymerase chain reaction one of the most reliable, provided strict precautions are taken against cross contamination. The review concludes with a brief summary of the changes that took place after European exploration and colonisation.

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Durante los procedimientos endovasculares en el ictus isquémico la información per-procedimiento del daño cerebral ayudaría a tomar decisiones sobre intentar la recanalización arterial. Métodos Se estudiaron parámetros gasométricos de sangre extraída durante los procedimientos endovasculares de recanalización. Se obtuvieron muestras proximal y distal a la oclusión. Un estudio gasométrico se realizo inmediatamente. Resultados El estudio mostró diferencias significativas entre las muestras pre-oclusión y postoclusión en la presión parcial de oxígeno (PaO2Pre78,9±16.3mmHgVs73.4±14.9 mmHg,p&0,001). Una curva ROC determinó que una Post-PaO2&70 mmHg predice mejoría clínica. Los pacientes con post-PaO2&70mmHg tuvieron mejor autonomía (medianaMRS:3Vs.6, p=0,024). En el análisis multivariante el único predictor independiente de mejoría clínica fue la Post-PaO2&70(OR:5,21IC95%:1.38-67.24,p=0,013). Conclusión Es posible la obtención de muestras de sangre del tejido lesionado distal a la oclusión. La información puede ser utilizada para predecir evolución clínica y en las decisiones durante el procedimiento.

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BACKGROUND Cancer survivors are advised to follow lifestyle recommendations on diet, physical activity, and body fatness proposed by the World Cancer Research Fund/American Institute of Cancer Research (WCRF/AICR) for cancer prevention. Previous studies have demonstrated that higher concordance with these recommendations measured using an index score (the WCRF/AICR score) was associated with lower cancer incidence and mortality. The aim of this study was to evaluate the association between pre-diagnostic concordance with WCRF/AICR recommendations and mortality in colorectal cancer (CRC) patients. METHODS The association between the WCRF/AICR score (score range 0-6 in men and 0-7 in women; higher scores indicate greater concordance) assessed on average 6.4 years before diagnosis and CRC-specific (n = 872) and overall mortality (n = 1,113) was prospectively examined among 3,292 participants diagnosed with CRC in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort (mean follow-up time after diagnosis 4.2 years). Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality. RESULTS The HRs (95% CIs) for CRC-specific mortality among participants in the second (score range in men/women: 2.25-2.75/3.25-3.75), third (3-3.75/4-4.75), and fourth (4-6/5-7) categories of the score were 0.87 (0.72-1.06), 0.74 (0.61-0.90), and 0.70 (0.56-0.89), respectively (P for trend <0.0001), compared to participants with the lowest concordance with the recommendations (category 1 of the score: 0-2/0-3). Similar HRs for overall mortality were observed (P for trend 0.004). Meeting the recommendations on body fatness and plant food consumption were associated with improved survival among CRC cases in mutually adjusted models. CONCLUSIONS Greater concordance with the WCRF/AICR recommendations on diet, physical activity, and body fatness prior to CRC diagnosis is associated with improved survival among CRC patients.