Research on astronaut health and model organisms have revealed six features of spaceflight biology that guide our current understanding of fundamental molecular changes that occur during space ...travel. The features include oxidative stress, DNA damage, mitochondrial dysregulation, epigenetic changes (including gene regulation), telomere length alterations, and microbiome shifts. Here we review the known hazards of human spaceflight, how spaceflight affects living systems through these six fundamental features, and the associated health risks of space exploration. We also discuss the essential issues related to the health and safety of astronauts involved in future missions, especially planned long-duration and Martian missions.
An international group of spaceflight researchers detail how spaceflight affects human biology from the molecular to physiological level and identify key challenges for making space exploration compatible with human health.
The impact of weightlessness on the female reproductive system remains poorly understood, although deep space exploration is impossible without the development of effective measures to protect ...women's health. The purpose of this work was to study the effect of a 5-day "dry" immersion on the state of the reproductive system of female subjects. On the fourth day of the menstrual cycle after immersion, we observed an increase in inhibin B of 35% (
< 0.05) and a decrease in luteinizing hormone of 12% (
< 0.05) and progesterone of 52% (
< 0.05) compared with the same day before immersion. The size of the uterus and the thickness of the endometrium did not change. On the ninth day of the menstrual cycle after immersion, the average diameters of the antral follicles and the dominant follicle were, respectively, 14% and 22% (
< 0.05) higher than before. The duration of the menstrual cycle did not change. The obtained results may indicate that the stay in the 5-day "dry" immersion, on the one hand, can stimulate the growth of the dominant follicle, but, on the other hand, can cause functional insufficiency of the
.
Introduction:
A decrease in sleep quality and duration during space missions has repeatedly been reported. However, the exact causes that underlie this effect remain unclear. In space, sleep might be ...impacted by weightlessness and its influence on cardiovascular function. In this study, we aimed at exploring the changes of night sleep architecture during prolonged, 21-day Dry Immersion (DI) as one of the ground-based models for microgravity studies and comparing them with adaptive changes in the cardiovascular system.
Methods:
Ten healthy young men were exposed to DI for 21 days. The day before (baseline, B-1), on the 3rd (DI3), 10th (DI10), and 19th (DI19) day of DI, as well as in the recovery period, 1 day after the end of DI (R + 1), they were subjected to overnight polysomnography (PSG) and ambulatory blood pressure monitoring.
Results:
On DI3, when the most severe back pain occurred due to the effects of DI on the spine and back muscles, the PSG data showed dramatically disorganized sleep architecture. Sleep latency, the number of awakenings, and the duration of wake after sleep onset (WASO) were significantly increased compared with the B-1. Furthermore, the sleep efficiency, duration of rapid eye movement sleep (REM), and duration of non-rapid eye movement stage 2 decreased. On DI10, subjective pain ratings declined to 0 and sleep architecture returned to the baseline values. On DI19, the REM duration increased and continued to rise on R + 1. An increase in REM was accompanied by rising in a nighttime heart rate (HR), which also shows the most significant changes after the end of DI. On DI19 and R + 1, the REM duration showed opposite correlations with the BP parameters: on DI19 it was negatively associated with the systolic BP (SBP), and on R + 1 it was positively correlated with the diastolic BP (DBP).
Conclusion:
An increase in REM at the end of DI and in recovery might be associated with regulatory changes in the cardiovascular system, in particular, with the reorganization of the peripheral and central blood flow in response to environmental changes.
To analyze the effect of gravity on the structure of germinal tissues, we examined tissues of the testes and duct deferens of mice that were exposed to space flight conditions for 21-24 days ...(experiment Rodent Research-4, SpaceX-10 mission, February 2017, USA). We evaluated the levels of cytoskeletal proteins, sperm-specific proteins, and epigenetic events; in particular, we evaluated levels of 5-hydroxymethylcytosine and of enzymes that regulate DNA methylation/demethylation. We did not detect changes in the levels of cytoskeletal proteins, sperm-specific proteins, DNA-methylases, DNA demethylases, DNA acetylases, or histone deacetylases. However, there were changes at the gene expression level. In particular, there was an increase in the demethylase Tet2 and a decrease in the histone deacetylase Hdac1. These gene expression changes may be of key importance during the early period of readaptation since they could lead to an increase in the expression of target genes.
The role of the Earth's gravitational and magnetic fields in the evolution and maintenance of normal processes of various animal species remains unclear. The aim of this work was to determine the ...effect of simulated microgravity and hypomagnetic conditions for 1, 3, and 6 h on the sperm motility of the fruit fly
. In addition to the usual diet, the groups were administered oral essential phospholipids at a dosage of 500 mg/kg in medium. The speed of the sperm tails was determined by video recording and analysis of the obtained video files, protein content by western blotting, and cell respiration by polarography. The results indicated an increase in the speed of movement of the sperm tails after 6 h in simulated microgravity. The levels of proteins that form the axoneme of the sperm tail did not change, but cellular respiration was altered. A similar effect occurred with the administration of essential phospholipids. These results may be due to a change in the level of phosphorylation of motor proteins. Exposure to hypomagnetic conditions led to a decrease in motility after 6 h against a background of a decrease in the rate of cellular respiration due to complex I of the respiratory chain. This effect was not observed in the flies that received essential phospholipids. However, after 1 h under hypomagnetic conditions, the rate of cellular respiration also increased due to complex I, including that in the sperm of flies receiving essential phospholipids.
Mechanochemically assisted extraction involves the mechanical treatment of powder mixtures of plant materials and convenient reagents in special mill-activators to solubilize the biologically active ...substances. The reactions of the solid hydroxides, carbonates, and hydrocarbonates of alkali metals are the subject of this paper. During mechanochemical treatment, insoluble biologically active substances are transformed into water-soluble or highly reactive mechanocomposites. The types of reagents used depend on the chemical nature of the biologically active substance and the possible chemical reactions between the substance and reagents. Solid-state mechanochemical reactions between active acids and solid bases and between biogenic amines and acids and the formation of soluble complexes of biologically active substances with water-soluble and insoluble polymers were explored in this study. The advantages of using these reactions in mechanochemically assisted extraction are presented in this review.
The soleus muscle in humans is responsible for maintaining an upright posture and participating in walking and running. Under muscle disuse, it undergoes molecular signaling changes that result in ...altered force and work capacity. The triggering mechanisms and pathways of these changes are not yet fully understood. In this article, we aimed to detect the molecular pathways that are involved in the unloading-induced alterations in the human soleus muscle under 6-days of dry immersion. A 6-day dry immersion led to the downregulation of mitochondrial biogenesis and dynamics markers, upregulation of calcium-dependent CaMK II phosphorylation, enhanced PGC1α promoter region methylation, and altered muscle micro-RNA expression, without affecting p-AMPK content or fiber-type transformation.
Dry immersion dysregulates mitochondrial genes expression, affects mi-RNA expression and PGC1 promoter methylation.
We aimed to explore the effect of the 3-day dry immersion, a model of physical unloading, on mitochondrial function, transcriptomic and proteomic profiles in a slow-twitch soleus muscle of six ...healthy females. We registered that a marked reduction (25-34%) in the ADP-stimulated respiration in permeabilized muscle fibers was not accompanied by a decrease in the content of mitochondrial enzymes (mass spectrometry-based quantitative proteomics), hence, it is related to the disruption in regulation of respiration. We detected a widespread change in the transcriptomic profile (RNA-seq) upon dry immersion. Downregulated mRNAs were strongly associated with mitochondrial function, as well as with lipid metabolism, glycolysis, insulin signaling, and various transporters. Despite the substantial transcriptomic response, we found no effect on the content of highly abundant proteins (sarcomeric, mitochondrial, chaperon, and extracellular matrix-related, etc.) that may be explained by long half-life of these proteins. We suggest that during short-term disuse the content of some regulatory (and usually low abundant) proteins such as cytokines, receptors, transporters, and transcription regulators is largely determined by their mRNA concentration. These mRNAs revealed in our work may serve as putative targets for future studies aimed at developing approaches for the prevention of muscle deconditioning induced by disuse.
Three-day dry immersion (a model of physical unloading) substantially changes the transcriptomic profile in the human soleus muscle, a muscle with predominantly slow-twitch fibers and strong postural function; despite this, we found no effect on the muscle proteome (highly abundant proteins). Dry immersion markedly reduces ADP-stimulated respiration; this decline is not accompanied by a decrease in the content of mitochondrial proteins/respiratory enzymes, indicating the disruption in regulation of cellular respiration.
Aortic Root Pseudoaneurysm Caused by Mycobacterium Chimaera Shah, Vishal N.; Orlov, Oleg I.; Sternlieb, Mitchell P. ...
The Annals of thoracic surgery,
February 2019, 2019-Feb, 2019-02-00, 20190201, Letnik:
107, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Nontuberculous mycobacteria cause severe pulmonary, vascular graft, and bloodstream infections after cardiac surgery. Patient prognosis remains poor because of delays in diagnosis and treatment. ...Complicated aortic root infections caused by nontuberculous mycobacteria have been mostly fatal. We describe a case of a 50-year-old man who developed an invasive Mycobacterium chimaera infection with an aortic root pseudoaneurysm after a Bentall-de Bono procedure for a Stanford type A aortic dissection.
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