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- Rojc, Bojan, et al.
(författare)
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The separate and combined effects of hypoxia and sustained recumbency/inactivity on sleep architecture
- 2014
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 114:9, s. 1973-1981
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Tidskriftsartikel (refereegranskat)abstract
- The objective was to determine the separate and combined effects of hypoxia and inactivity/unloading on sleep architecture during a 10-day period of confinement. Ten subjects participated in three 10-day trials in random order: hypoxic ambulatory (HAMB), hypoxic bedrest (HBR), and normoxic bedrest (NBR). During the HAMB and HBR trials, subjects were confined to a hypoxic facility. The hypoxia profile was: simulated altitude of 2,990 m on day 1, 3,380 m on day 2, and 3,881 m on day 3. In the NBR and HBR trials, subjects maintained a horizontal position throughout the confinement period. During each trial, sleep polysomnography was conducted one night prior to (baseline; altitude of facility is 940 m) and on the first (NT1, altitude 2,990 m) and tenth (NT10, altitude 3,881 m) night of the 10-day intervention. Average time in sleep stage 1 decreased from NT1 to NT10 irrespective of trial. Overall incidence and time spent in periodic breathing increased from NT1 to NT10 in both HAMB and HBR. During NT1, both HAMB and HBR reduced slow-wave sleep and increased light sleep, whereas NBR and HBR increased the number of awakenings/night. There were fewer awakenings during HAMB than NBR. Acute exposure to both hypoxia and bedrest (HBR) results in greater sleep fragmentation due to more awakenings attributed to bedrest, and lighter sleep as a result of reduced slow wave sleep caused by the hypoxic environment.
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| 2. |
- Tellez, Helio Fernandez, et al.
(författare)
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Exercise during Short-Term and Long-Term Continuous Exposure to Hypoxia Exacerbates Sleep-Related Periodic Breathing
- 2016
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Ingår i: Sleep. - : Associated Professional Sleep Societies. - 0161-8105 .- 1550-9109. ; 39:4, s. 773-783
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Tidskriftsartikel (refereegranskat)abstract
- Study Objectives: Exposure to hypoxia elevates chemosensitivity, which can lead to periodic breathing. Exercise impacts gas exchange, altering chemosensitivity; however, interactions between sleep, exercise and chronic hypoxic exposure have not been examined. This study investigated whether exercise exacerbates sleep-related periodic breathing in hypoxia. Methods: Two experimental phases. Short-Term Phase: a laboratory controlled, group-design study in which 16 active, healthy men (age: 25 +/- 3 y, height: 1.79 +/- 0.06 m, mass: 74 +/- 8 kg) were confined to a normobaric hypoxic environment (FIO2 = 0.139 +/- 0.003, 4,000 m) for 10 days, after random assignment to a sedentary (control, CON) or cycle-exercise group (EX). Long-Term Phase: conducted at the Concordia Antarctic Research Station (3,800 m equivalent at the Equator) where 14 men (age: 36 +/- 9 y, height: 1.77 +/- 0.09 m, mass: 75 +/- 10 kg) lived for 12-14 months, continuously confined. Participants were stratified post hoc based on self-reported physical activity levels. We quantified apnea-hypopnea index (AHI) and physical activity variables. Results: Short-Term Phase: mean AHI scores were significantly elevated in the EX group compared to CON (Night1 = CON: 39 +/- 51, EX: 91 +/- 59; Night10 = CON: 32 +/- 32, EX: 92 +/- 48; P = 0.046). Long-Term Phase: AHI was correlated to mean exercise time (R-2 = 0.4857; P = 0.008) and the coefficient of variation in night oxyhemoglobin saturation (SpO(2); R-2 = 0.3062; P = 0.049). Conclusions: Data indicate that exercise (physical activity) per se affects night SpO(2) concentrations and AHI after a minimum of two bouts of moderateintensity hypoxic exercise, while habitual physical activity in hypobaric hypoxic confinement affects breathing during sleep, up to 13+ months' duration
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| 3. |
- van Rheenen, Wouter, et al.
(författare)
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Genome-wide association analyses identify new risk variants and the genetic architecture of amyotrophic lateral sclerosis
- 2016
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 48:9, s. 1043-1048
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Tidskriftsartikel (refereegranskat)abstract
- To elucidate the genetic architecture of amyotrophic lateral sclerosis (ALS) and find associated loci, we assembled a custom imputation reference panel from whole-genome-sequenced patients with ALS and matched controls (n = 1,861). Through imputation and mixed-model association analysis in 12,577 cases and 23,475 controls, combined with 2,579 cases and 2,767 controls in an independent replication cohort, we fine-mapped a new risk locus on chromosome 21 and identified C21orf2 as a gene associated with ALS risk. In addition, we identified MOBP and SCFD1 as new associated risk loci. We established evidence of ALS being a complex genetic trait with a polygenic architecture. Furthermore, we estimated the SNP-based heritability at 8.5%, with a distinct and important role for low-frequency variants (frequency 1-10%). This study motivates the interrogation of larger samples with full genome coverage to identify rare causal variants that underpin ALS risk.
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