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1.
Meta-analysis of Oxygenation Saturation Targeting Trials: Do Infant Subgroups Matter?
Askie, LM
Clinics in perinatology. 2019;(3):579-591
Abstract
Participant data from approximately 5000 infants have been meta-analyzed to guide oxygen saturation policy for extremely preterm infants. The Neonatal Oxygenation Prospective Meta-analysis showed that targeting a higher oxygen saturation range compared with a lower range resulted in decreased death and necrotizing enterocolitis and no difference in major disability but increased treated retinopathy of prematurity (ROP) and supplemental oxygen use at 36 weeks' postmenstrual age. The 91% to 95% range can be recommended for all extremely preterm infants from birth but should be accompanied by stringent surveillance for the prevention and early treatment of ROP.
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2.
Achieved Oxygenation Saturations and Outcome in Extremely Preterm Infants.
Stenson, BJ
Clinics in perinatology. 2019;(3):601-610
Abstract
Infants in the Neonatal Oxygenation Prospective Meta-analysis trials were randomized to SpO2 targets of 85% to 89% or 91% to 95%. Group allocation was masked. Different outcomes are likely partially attributable to differences in achieved SpO2. Infants randomized to the lower range had higher than intended readings. SpO2 distributions of infants in the low-range group of the Benefits of Oxygen Saturation Targeting II UK trial who died or developed necrotizing enterocolitis were centered around 90% to 92%. These achieved SpO2 distributions caution against using lower SpO2 target ranges early or throughout the clinical course in extremely preterm infants.
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3.
The Role of Gas Exchange Variables in Cardiopulmonary Exercise Testing for Risk Stratification and Management of Heart Failure with Reduced Ejection Fraction.
Wagner, J, Agostoni, P, Arena, R, Belardinelli, R, Dumitrescu, D, Hager, A, Myers, J, Rauramaa, R, Riley, M, Takken, T, et al
American heart journal. 2018;:116-126
Abstract
Heart failure with reduced ejection fraction (HFrEF) is common in the developed world and results in significant morbidity and mortality. Accurate risk assessment methods and prognostic variables are therefore needed to guide clinical decision making for medical therapy and surgical interventions with the ultimate goal of decreasing risk and improving health outcomes. The purpose of this review is to examine the role of cardiopulmonary exercise testing (CPET) and its most commonly used ventilatory gas exchange variables for the purpose of risk stratification and management of HFrEF. We evaluated five widely studied gas exchange variables from CPET in HFrEF patients based on nine previously used systematic criteria for biomarkers. This paper provides clinicians with a comprehensive and critical overview, class recommendations and evidence levels. Although some CPET variables met more criteria than others, evidence supporting the clinical assessment of variables beyond peak V̇O2 is well-established. A multi-variable approach also including the V̇E-V̇CO2 slope and EOV is therefore recommended.
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4.
Measurement of Transcripts Associated with Photorespiration and Related Redox Signaling.
Mhamdi, A, Kerchev, PI, Willems, P, Noctor, G, Van Breusegem, F
Methods in molecular biology (Clifton, N.J.). 2017;:17-29
Abstract
To study photorespiration and to characterize related components, gene expression analysis is a central approach. An overview of the experimental setup, protocols, and methods we use to investigate photorespiration-associated gene expression is presented. Within this chapter, we describe simple procedures to experimentally alter the photorespiratory flux and provide protocols for transcriptomic analysis with a focus on genes encoding photorespiratory proteins as well as those induced by photorespiratory hydrogen peroxide (H2O2). Examples of typical results are presented and their significance to understanding redox signaling is discussed.
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5.
Genes to predict VO2max trainability: a systematic review.
Williams, CJ, Williams, MG, Eynon, N, Ashton, KJ, Little, JP, Wisloff, U, Coombes, JS
BMC genomics. 2017;(Suppl 8):831
Abstract
BACKGROUND Cardiorespiratory fitness (VO2max) is an excellent predictor of chronic disease morbidity and mortality risk. Guidelines recommend individuals undertake exercise training to improve VO2max for chronic disease reduction. However, there are large inter-individual differences between exercise training responses. This systematic review is aimed at identifying genetic variants that are associated with VO2max trainability. METHODS Peer-reviewed research papers published up until October 2016 from four databases were examined. Articles were included if they examined genetic variants, incorporated a supervised aerobic exercise intervention; and measured VO2max/VO2peak pre and post-intervention. RESULTS Thirty-five articles describing 15 cohorts met the criteria for inclusion. The majority of studies used a cross-sectional retrospective design. Thirty-two studies researched candidate genes, two used Genome-Wide Association Studies (GWAS), and one examined mRNA gene expression data, in addition to a GWAS. Across these studies, 97 genes to predict VO2max trainability were identified. Studies found phenotype to be dependent on several of these genotypes/variants, with higher responders to exercise training having more positive response alleles than lower responders (greater gene predictor score). Only 13 genetic variants were reproduced by more than two authors. Several other limitations were noted throughout these studies, including the robustness of significance for identified variants, small sample sizes, limited cohorts focused primarily on Caucasian populations, and minimal baseline data. These factors, along with differences in exercise training programs, diet and other environmental gene expression mediators, likely influence the ideal traits for VO2max trainability. CONCLUSION Ninety-seven genes have been identified as possible predictors of VO2max trainability. To verify the strength of these findings and to identify if there are more genetic variants and/or mediators, further tightly-controlled studies that measure a range of biomarkers across ethnicities are required.
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6.
Effectiveness of resistance exercise compared to aerobic exercise without insulin therapy in patients with type 2 diabetes mellitus: a meta-analysis.
Nery, C, Moraes, SRA, Novaes, KA, Bezerra, MA, Silveira, PVC, Lemos, A
Brazilian journal of physical therapy. 2017;(6):400-415
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Abstract
BACKGROUND Physical exercise has been used to mitigate the metabolic effects of diabetes mellitus. OBJECTIVE To evaluate the effect of resistance exercise when compared to aerobic exercise without insulin therapy on metabolic and clinical outcomes in patients with type 2 diabetes mellitus. METHODS Papers were searched on the databases MEDLINE/PubMed, CINAHL, SPORTDiscus, LILACS, and SCIELO, without language or date of publication limits. Clinical trials that compared resistance exercise to aerobic exercise in adults with type 2 diabetes mellitus who did not use insulin therapy were included. The quality of evidence and risk of bias were assessed using the GRADE system and the Cochrane Risk of Bias tool, respectively. Meta-analysis was also used, whenever possible. Two reviewers extracted the data independently. Eight eligible articles were included in this study, with a total of 336 individuals, with a mean age of 48-58 years. The protocols of aerobic and resistance exercise varied in duration from eight to 22 weeks, 30-60min/day, three to five times/week. RESULTS Overall the available evidence came from a very low quality of evidence and there was an increase in Maximal oxygen consumption (mean difference: -2.86; 95% CI: -3.90 to -1.81; random effect) for the resistance exercise and no difference was found in Glycated hemoglobin, Body mass index, High-density lipoprotein cholesterol, Low-density lipoprotein cholesterol, triglycerides, and total cholesterol. CONCLUSIONS Resistance exercise appears to be more effective in promoting an increase in Maximal oxygen consumption in protocols longer than 12 weeks and there is no difference in the control of glycemic and lipid levels between the two types of exercise.
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7.
Hypoxic Pulmonary Vasoconstriction: From Molecular Mechanisms to Medicine.
Dunham-Snary, KJ, Wu, D, Sykes, EA, Thakrar, A, Parlow, LRG, Mewburn, JD, Parlow, JL, Archer, SL
Chest. 2017;(1):181-192
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Abstract
Hypoxic pulmonary vasoconstriction (HPV) is a homeostatic mechanism that is intrinsic to the pulmonary vasculature. Intrapulmonary arteries constrict in response to alveolar hypoxia, diverting blood to better-oxygenated lung segments, thereby optimizing ventilation/perfusion matching and systemic oxygen delivery. In response to alveolar hypoxia, a mitochondrial sensor dynamically changes reactive oxygen species and redox couples in pulmonary artery smooth muscle cells (PASMC). This inhibits potassium channels, depolarizes PASMC, activates voltage-gated calcium channels, and increases cytosolic calcium, causing vasoconstriction. Sustained hypoxia activates rho kinase, reinforcing vasoconstriction, and hypoxia-inducible factor (HIF)-1α, leading to adverse pulmonary vascular remodeling and pulmonary hypertension (PH). In the nonventilated fetal lung, HPV diverts blood to the systemic vasculature. After birth, HPV commonly occurs as a localized homeostatic response to focal pneumonia or atelectasis, which optimizes systemic Po2 without altering pulmonary artery pressure (PAP). In single-lung anesthesia, HPV reduces blood flow to the nonventilated lung, thereby facilitating thoracic surgery. At altitude, global hypoxia causes diffuse HPV, increases PAP, and initiates PH. Exaggerated or heterogeneous HPV contributes to high-altitude pulmonary edema. Conversely, impaired HPV, whether due to disease (eg, COPD, sepsis) or vasodilator drugs, promotes systemic hypoxemia. Genetic and epigenetic abnormalities of this oxygen-sensing pathway can trigger normoxic activation of HIF-1α and can promote abnormal metabolism and cell proliferation. The resulting pseudohypoxic state underlies the Warburg metabolic shift and contributes to the neoplasia-like phenotype of PH. HPV and oxygen sensing are important in human health and disease.
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Photo and Nutritional Regulation of Euglena Organelle Development.
Schwartzbach, SD
Advances in experimental medicine and biology. 2017;:159-182
Abstract
Euglena can use light and CO2, photosynthesis, as well as a large variety of organic molecules as the sole source of carbon and energy for growth. Light induces the enzymes, in this case an entire organelle, the chloroplast, that is required to use CO2 as the sole source of carbon and energy for growth. Ethanol, but not malate, inhibits the photoinduction of chloroplast enzymes and induces the synthesis of the glyoxylate cycle enzymes that comprise the unique metabolic pathway leading to two carbon, ethanol and acetate, assimilation. In resting, carbon starved cells, light mobilizes the degradation of the storage carbohydrate paramylum and transiently induces the mitochondrial proteins required for the aerobic metabolism of paramylum to provide the carbon and energy required for chloroplast development. Other mitochondrial proteins are degraded upon light exposure providing the amino acids required for the synthesis of light induced proteins. Changes in protein levels are due to increased and decreased rates of synthesis rather than changes in degradation rates. Changes in protein synthesis rates occur in the absence of a concomitant increase in the levels of mRNAs encoding these proteins indicative of photo and metabolic control at the translational rather than the transcriptional level. The fraction of mRNA encoding a light induced protein such as the light harvesting chlorophyll a/b binding protein of photosystem II, (LHCPII) associated with polysomes in the dark is similar to the fraction associated with polysomes in the light indicative of photoregulation at the level of translational elongation. Ethanol, a carbon source whose assimilation requires carbon source specific enzymes, the glyoxylate cycle enzymes, represses the synthesis of chloroplast enzymes uniquely required to use light and CO2 as the sole source of carbon and energy for growth. The catabolite sensitivity of chloroplast development provides a mechanism to prioritize carbon source utilization. Euglena uses all of its resources to develop the metabolic capacity to utilize carbon sources such as ethanol which are rarely in the environment and delays until the rare carbon source is no longer available forming the chloroplast which is required to utilize the ubiquitous carbon source, light and CO2.
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Submaximal Exercise-Based Equations to Predict Maximal Oxygen Uptake in Older Adults: A Systematic Review.
Smith, AE, Evans, H, Parfitt, G, Eston, R, Ferrar, K
Archives of physical medicine and rehabilitation. 2016;(6):1003-12
Abstract
OBJECTIVE To evaluate and discuss the accuracy of submaximal exercise-based equations to predict maximum oxygen uptake (V˙o2max), validated using direct gas analysis, in older apparently healthy adults. DATA SOURCES Studies were identified by searching 5 electronic databases and manually scanning reference lists of included articles from the respective inception of each database through April 2015. STUDY SELECTION Studies were included if they used at least 1 submaximal exercise-based variable in the prediction, the actual V˙o2max was directly measured using a gas analysis device, and if participants were apparently healthy older adults (mean age ≥65y). Eligible studies were required to report at least 1 validity statistic (eg, Pearson product-moment correlation [r]) and either a predicted and measured V˙o2max value or a directional significant difference between the measured and predicted V˙o2max values. No limits were placed on year of publication, but only full-text, published articles in the English language were included. DATA EXTRACTION Nine articles and 13 equations were retained from the systematic search strategy. If the same prediction equation was used across multiple trials, data from the most accurate trial were reported. DATA SYNTHESIS Submaximal equations predicted directly measured V˙o2max with a moderate to strong correlation strength (r range, 0.4-0.9). Predicted V˙o2max significantly differed from directly measured in 2 of the 13 equations. The preferred mode of ergometry was walking or running (7 equations); a stepping protocol was the most accurate (R(2)=0.9, not significant between predicted and measured V˙o2max). CONCLUSIONS Factors to consider when choosing a submaximal exercise-based equation are the accuracy of the equation, the population tested, the mode of ergometry, the equipment availability, and the time needed to conduct familiarization sessions.
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Is Recreational Soccer Effective for Improving VO2max A Systematic Review and Meta-Analysis.
Milanović, Z, Pantelić, S, Čović, N, Sporiš, G, Krustrup, P
Sports medicine (Auckland, N.Z.). 2015;(9):1339-1353
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Abstract
BACKGROUND Soccer is the most popular sport worldwide, with a long history and currently more than 500 million active participants, of whom 300 million are registered football club members. On the basis of scientific findings showing positive fitness and health effects of recreational soccer, FIFA (Fédération Internationale de Football Association) introduced the slogan "Playing football for 45 min twice a week-best prevention of non-communicable diseases" in 2010. OBJECTIVE The objective of this paper was to perform a systematic review and meta-analysis of the literature to determine the effects of recreational soccer on maximal oxygen uptake (VO2max). METHODS Six electronic databases (MEDLINE, PubMed, SPORTDiscus, Web of Science, CINAHL and Google Scholar) were searched for original research articles. A manual search was performed to cover the areas of recreational soccer, recreational physical activity, recreational small-sided games and VO2max using the following key terms, either singly or in combination: recreational small-sided games, recreational football, recreational soccer, street football, street soccer, effect, maximal oxygen uptake, peak oxygen uptake, cardiorespiratory fitness, VO2max. The inclusion criteria were divided into four sections: type of study, type of participants, type of interventions and type of outcome measures. Probabilistic magnitude-based inferences for meta-analysed effects were based on standardised thresholds for small, moderate and large changes (0.2, 0.6 and 1.2, respectively) derived from between-subject standard deviations for baseline fitness. RESULTS Seventeen studies met the inclusion criteria and were included in the systematic review and meta-analysis. Mean differences showed that VO2max increased by 3.51 mL/kg/min (95 % CI 3.07-4.15) over a recreational soccer training programme in comparison with other training models. The meta-analysed effects of recreational soccer on VO2max compared with the controls of no exercise, continuous running and strength training were most likely largely beneficial [effect size (ES) = 1.46; 95 % confidence interval (CI) 0.91, 2.01; I (2) = 88.35 %], most likely moderately beneficial (ES = 0.68; 95 % CI 0.06, 1.29; I (2) = 69.13 %) and most likely moderately beneficial (ES = 1.08; 95 % CI -0.25, 2.42; I (2) = 71.06 %), respectively. In men and women, the meta-analysed effect was most likely largely beneficial for men (ES = 1.22) and most likely moderately beneficial for women (ES = 0.96) compared with the controls. After 12 weeks of recreational soccer with an intensity of 78-84 % maximal heart rate (HRmax), healthy untrained men improved their VO2max by 8-13 %, while untrained elderly participants improved their VO2max by 15-18 %. Soccer training for 12-70 weeks in healthy women resulted in an improvement in VO2max of 5-16 %. Significant improvements in VO2max have been observed in patients with diabetes mellitus, hypertension and prostate cancer. CONCLUSION Recreational soccer produces large improvements in VO2max compared to strength training and no exercise, regardless of the age, sex and health status of the participants. Furthermore, recreational soccer is better than continuous endurance running, albeit the additional effect is moderate. This kind of physical activity has great potential for enhancing aerobic fitness, and for preventing and treating non-communicable diseases, and is ideal for addressing lack of motivation, a key component in physical (in)activity.