scholarly journals The Role of Long-Term Head-Down Bed Rest in Understanding Inter-Individual Variation in Response to the Spaceflight Environment: A Perspective Review

2021 ◽  
Vol 12 ◽  
Author(s):  
Jonathan P. R. Scott ◽  
Andreas Kramer ◽  
Nora Petersen ◽  
David A. Green
Keyword(s):  
Bed Rest ◽  
Individual Variability ◽  
Control Group ◽  
Statistical Concept ◽  
Gravitational Unloading ◽  
Experimental Conditions ◽  
Mechanical Unloading ◽  
Musculoskeletal Systems

Exposure to the spaceflight environment results in profound multi-system physiological adaptations in which there appears to be substantial inter-individual variability (IV) between crewmembers. However, performance of countermeasure exercise renders it impossible to separate the effects of the spaceflight environment alone from those associated with exercise, whilst differences in exercise programs, spaceflight operations constraints, and environmental factors further complicate the interpretation of IV. In contrast, long-term head-down bed rest (HDBR) studies isolate (by means of a control group) the effects of mechanical unloading from those associated with countermeasures and control many of the factors that may contribute to IV. In this perspective, we review the available evidence of IV in response to the spaceflight environment and discuss factors that complicate its interpretation. We present individual data from two 60-d HDBR studies that demonstrate that, despite the highly standardized experimental conditions, marked quantitative differences still exist in the response of the cardiorespiratory and musculoskeletal systems between individuals. We also discuss the statistical concept of “true” and “false” individual differences and its potential application to HDBR data. We contend that it is currently not possible to evaluate IV in response to the spaceflight environment and countermeasure exercise. However, with highly standardized experimental conditions and the presence of a control group, HDBR is suitable for the investigation of IV in the physiological responses to gravitational unloading and countermeasures. Such investigations may provide valuable insights into the potential role of IV in adaptations to the spaceflight environment and the effectiveness of current and future countermeasures.

scholarly journals Electrocortical Evidence for Impaired Affective Picture Processing after Long-Term Immobilization

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Katharina Brauns ◽  
Anika Werner ◽  
Hanns-Christian Gunga ◽  
Martina A. Maggioni ◽  
David F. Dinges ◽  
...  
Keyword(s):  
Physical Inactivity ◽  
Event Related Potentials ◽  
Bed Rest ◽  
Control Group ◽  
Picture Processing ◽  
Long Duration ◽  
Related Potentials ◽  
Time Frames

Abstract The neurobehavioral risks associated with spaceflight are not well understood. In particular, little attention has been paid on the role of resilience, social processes and emotion regulation during long-duration spaceflight. Bed rest is a well-established spaceflight analogue that combines the adaptations associated with physical inactivity and semi-isolation and confinement. We here investigated the effects of 30 days of 6 degrees head-down tilt bed rest on affective picture processing using event-related potentials (ERP) in healthy men. Compared to a control group, bed rest participants showed significantly decreased P300 and LPP amplitudes to pleasant and unpleasant stimuli, especially in centroparietal regions, after 30 days of bed rest. Source localization revealed a bilateral lower activity in the posterior cingulate gyrus, insula and precuneus in the bed rest group in both ERP time frames for emotional, but not neutral stimuli.

scholarly journals Intermittent short-arm centrifugation is a partially effective countermeasure against upright balance deterioration following 60-day head-down tilt bed rest

2021 ◽  
Author(s):  
Enrico De Martino ◽  
Sauro Emerick Salomoni ◽  
Paul W. Hodges ◽  
Julie Hides ◽  
Kirsty Lindsay ◽  
...  
Keyword(s):  
Bed Rest ◽  
Standing Balance ◽  
Erector Spinae ◽  
Transversus Abdominis ◽  
Trunk Muscles ◽  
Control Group ◽  
Protective Effects ◽  
Gravitational Unloading ◽  
Frequency Power ◽  
Sway Frequency

This study investigated whether artificial gravity (AG), induced by short-radius centrifugation, mitigated deterioration in standing balance and anticipatory postural adjustments (APAs) of trunk muscles following 60-day head-down tilt bed rest. Twenty-four participants were allocated to one of three groups: control group (N=8); 30 minutes continuous AG daily (N=8); intermittent 6x5 minutes AG daily (N=8). Before and immediately after bed rest, standing balance was assessed in four conditions: eyes open and closed on both stable and foam surfaces. Measures including sway path, root-mean-square, and peak sway velocity, sway area, sway frequency power, and sway density curve were extracted from the centre of pressure displacement. APAs were assessed during rapid arm movements using intramuscular or surface electromyography electrodes of the rectus abdominis, obliquus externus and internus abdominis, transversus abdominis, erector spinae at L1, L2, L3, and L4 vertebral levels, and deep lumbar multifidus muscles. The relative latency between the EMG onset of the deltoid and each of the trunk muscles was calculated. All three groups had poorer balance performance in most of the parameters (all P<0.05) and delayed APAs of the trunk muscles following bed rest (all P<0.05). Sway path and sway velocity were deteriorated, and sway frequency power was less in those who received intermittent AG than in the control group (all P<0.05), particularly in conditions with reduced proprioceptive feedback. These data highlight the potential of intermittent AG to mitigate deterioration of some aspects of postural control induced by gravitational unloading, but no protective effects on trunk muscle responses were observed.

scholarly journals Complement activation products in acute heart failure: Potential role in pathophysiology, responses to treatment and impacts on long-term survival

2017 ◽  
Vol 7 (4) ◽  
pp. 348-357 ◽  
Author(s):  
Marten Trendelenburg ◽  
Fabio Stallone ◽  
Kateryna Pershyna ◽  
Timo Eisenhut ◽  
Raphael Twerenbold ◽  
...  
Keyword(s):  
Heart Failure ◽  
Acute Heart Failure ◽  
Complement Activation ◽  
Subgroup Analysis ◽  
Potential Role ◽  
Control Group ◽  
Term Survival ◽  
Activation Products

Background: Previous studies have indicated a correlation between heart failure, inflammation and poorer outcome. However, the pathogenesis and role of inflammation in acute heart failure (AHF) is incompletely studied and understood. The aim of our study was to explore the potential role of innate immunity – quantified by complement activation products (CAPs) – in pathophysiology, responses to treatment and impacts on long-term survival in AHF. Methods: In a prospective study enrolling 179 unselected patients with AHF, plasma concentrations of C4d, C3a and sC5b-9 were measured in a blinded fashion on the first day of hospitalisation and prior to discharge. The final diagnosis, including the AHF phenotype, was adjudicated by two independent cardiologists. Long-term follow-up was obtained. Findings in AHF were compared to that obtained in 75 healthy blood donors (control group). Results: Overall, concentrations of all three CAPs were significantly higher in patients with AHF than in healthy controls (all p < 0.001). In an age-adjusted subgroup analysis, significant differences could be confirmed for concentrations of C4d and sC5b-9, and these parameters further increased after 6 days of in-hospital treatment ( p < 0.001). In contrast, C3a levels in AHF patients did not differ from those of the control group in the age-adjusted subgroup analysis and remained constant during hospitalisation. Concentrations of C4d, C3a and sC5b-9 were significantly higher when AHF was triggered by an infection as compared to other triggers ( p < 0.001). In addition, CAP levels significantly correlated with each other ( r = 0.64–0.76), but did not predict death within 2 years. Conclusions: Activation of complement with increased plasma levels of C4d and sC5b-9 at admission and increasing levels during AHF treatment seems to be associated with AHF, particularly when AHF was triggered by an infection. However, CAPs do not have a prognostic value in AHF.

scholarly journals The role of the teacher in the implementation of a School-based intervention on the physical activity practice of children

2019 ◽  
Author(s):  
Tegwen Gadais ◽  
Theo Caron ◽  
Marie Belle Ayoub ◽  
Antony Karelis ◽  
Luc Nadeau
Keyword(s):  
Physical Activity ◽  
Elementary School Teachers ◽  
Intervention Group ◽  
Training Session ◽  
Control Group ◽  
Successful Implementation ◽  
School Teachers ◽  
School Based

INTRODUCTION: Medium or long term intervention strategies on physical activity practice (PAP) need to be more effective in their implementation by practitioners. The aim of this study was to evaluate the role of a teacher to implement the Team Pentathlon (TP) in order to improve the PAP in children. METHODS: 203 children (age: 10-13years), grades 5 and 6 (intervention group [IG] N = 104, control group [CG] N = 99) were guided to increase their PAP during an 8-week period by 5 elementary school teachers (physical education or classroom) who received 4 training sessions. Levels of PAP (self-reported) were compared between groups (IG/CG), sex, socioeconomic status of the schools and between teachers: baseline and during TP. RESULTS: Several teachers noted significant increases in PAP in the IG for both boys and girls (p&lt;.05 or p&lt;.01), whereas others found only small improvements in PAP. One teacher even observed higher PAP in the CG. Training session records revealed that the teacher himself, how the TP is implemented, and proper resources were the 3 elements that explained the successful implementation of the TP program. CONCLUSION: The implementation of the TP significantly increased the PAP in children. Training sessions helped teachers to implement the TP program but personal engagement, motivation, respecting protocol and adequate environment are necessary in improving the PAP of children.

scholarly journals The Role of the Teacher in the Implementation of a School-Based Intervention on the Physical Activity Practice of Children

2020 ◽  
Vol 17 (19) ◽  
pp. 7344
Author(s):  
Tegwen Gadais ◽  
Theo Caron ◽  
Marie-Belle Ayoub ◽  
Antony Karelis ◽  
Luc Nadeau
Keyword(s):  
Physical Activity ◽  
Elementary School Teachers ◽  
Intervention Group ◽  
Training Session ◽  
Control Group ◽  
Successful Implementation ◽  
School Teachers ◽  
School Based

Medium- or long-term intervention strategies for physical activity practice (PAP) need to be more effective in terms of their implementation by practitioners. The aim of this study was to evaluate the role of a teacher to implement the Team Pentathlon (TP) in order to improve the PAP in primary children. TP is a health education program made to improve PAP of children through individual and collective achievements. In this study, 203 children (age: 10–13 years) in grades 5 and 6 (intervention group (IG) N = 104, control group (CG) N = 99) were guided to increase their PAP during an eight-week period by five elementary school teachers (physical education or classroom) who had received four training sessions. Levels of PAP (self-reported) were compared between groups (IG/CG), sex, socioeconomic status of the schools and between teachers: baseline and during TP. Several teachers noted significant increases in PAP in the IG for both boys and girls (p ≤ 0.05 or p < 0.01), whereas others found only small improvements in PAP. One teacher even observed higher PAP in the CG. Training session records revealed that the teacher himself, how the TP is implemented, and proper resources were the three elements that explained the successful implementation of the TP program. The implementation of the TP significantly increased the PAP in primary children. Training sessions helped teachers to implement the TP program but personal engagement, motivation, respecting protocol, and an adequate environment are also necessary in improving the PAP of children.

Effect of PGI2 Infusion During Long Term Extracorporeal Circulation with Membrane Lung in Sheep

1981 ◽  
Vol 4 (3) ◽  
pp. 142-145 ◽  
Author(s):  
L. Uziel ◽  
A. Agostoni ◽  
E. Pirovano ◽  
A. Pesenti ◽  
A. Pelizzola ◽  
...  
Keyword(s):  
Extracorporeal Circulation ◽  
Low Dose ◽  
Control Group ◽  
Hemodynamic Changes ◽  
Experimental Conditions ◽  
Membrane Lung ◽  
Antiheparin Activity ◽  
Platelet Release ◽  
Small Platelet

PGI2 plus very low dose of heparin was infused in 6 lambs connected for long term extracorporeal circulation with a membrane lung. Hemodynamic and hemostasis parameters were compared to those of a control group treated only with standard doses of heparin. PGI2 efficacy in inhibiting platelet aggregation and platelet fall was confirmed. A small platelet release, measured as antiheparin activity, was observed during all the by-pass, but did not influence platelet capacity of recovering when PGI2 effect dissolved. Heparin needed resulted less than a quarter of the quantity used for the control group. In our experimental conditions the hemodynamic changes were mainly limited to a decrease in diastolic blood pressure.

scholarly journals The Role of Galectin-9 as Mediator of Atopic Dermatitis: Effect on Keratinocytes

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 947
Author(s):  
Mab P. Corrêa ◽  
Libnah L. Areias ◽  
Rebeca D. Correia-Silva ◽  
Solange C. G. P. D’Ávila ◽  
Andréia M. Leopoldino ◽  
...  
Keyword(s):  
Atopic Dermatitis ◽  
Human Keratinocytes ◽  
Allergic Diseases ◽  
Control Group ◽  
Biological Functions ◽  
Experimental Conditions ◽  
Control Growth ◽  
Tnf Α ◽  
Ifn Γ

Galectin-9 (Gal-9) is a beta-galactoside-binding protein with a variety of biological functions related to immune response. However, in allergic diseases, its mechanism of action is not fully understood. This study evaluates the expression pattern of Gal-9 in patients with atopic dermatitis (AD), in ovalbumin (OVA)-induced experimental atopic dermatitis (AD) in mice, as well as its effect on human keratinocytes. The skin of OVA-immunized BALB/c mice was challenged with drops containing OVA on days 11, 14–18, and 21–24. HaCaT cells were cultured in the following experimental conditions: control (growth medium only) or stimulated with TNF-α/IFN-γ, or IL-4, or IL-17 with or without Gal-9 treatment. AD was characterized by increased levels of Gal-9 in mouse and human skin, especially in the epidermis, and with a marked influx of Gal-9 positive eosinophils and mast cells compared to the control group. Gal-9 showed an immunomodulatory effect on keratinocytes by decreasing the release of IL-6 by IL-4-stimulated keratinocytes or increasing the IL-6 and RANTES levels by IL-17- or TNF-α/IFN-γ-stimulated cells, respectively. Under IL-17, Gal-9 treatment also altered the proliferation rate of cells. Overall, increased levels of Gal-9 in AD skin contribute to the control of inflammatory response and the proliferative process of keratinocytes, suggesting this lectin as a relevant therapeutic target.

The long-term effect of explicit instruction on learners’ knowledge on English articles

2017 ◽  
Vol 23 (2) ◽  
pp. 179-199 ◽  
Author(s):  
Mari Umeda ◽  
Neal Snape ◽  
Noriaki Yusa ◽  
John Wiltshier
Keyword(s):  
Explicit Knowledge ◽  
Explicit Instruction ◽  
Control Group ◽  
Instruction Group ◽  
Long Term Effect ◽  
One Year ◽  
English Articles ◽  
Generic Sentences

This study examines the role of explicit instruction in article semantics to L2 learners of English. Two types of generic sentences, expressed by different articles, were tested over time. An instruction group ( n = 21), a control group ( n = 16) and a native English speaker control group ( n = 9) participated in the study. The instruction group received nine 60-minute lessons across 9 weeks. A pre-test was administered to both groups before instruction began and four post-tests were given to both groups. The results from delayed post-tests show that the instruction group improved, but after one year little knowledge was retained. The findings suggest that explicit knowledge of articles is unlikely to be retained unless ongoing instruction is achieved.

Morphological and apoptotic changes in the intestinal mucosa and lung parenchyma after ischaemic/reperfusion injury of the jejunum

2010 ◽  
Vol 58 (2) ◽  
pp. 243-256 ◽  
Author(s):  
Ján Varga ◽  
Pavel Staško ◽  
Štefan Tóth ◽  
Zuzana Pristášová ◽  
Zuzana Jonecová ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Lung Parenchyma ◽  
Multiple Organ ◽  
Control Group ◽  
Jejunal Mucosa ◽  
Apoptotic Cells ◽  
Significant Difference ◽  
Long Term Experiment

Ischaemic/reperfusion (IR) injury of the small intestine may lead to the development of multiple organ failure. Little is known about the morphological changes occurring in the organs during the subacute course of this syndrome. The objective of this study was to observe histopathological features and the role of apoptosis in the jejunal mucosa and lung parenchyma after intestinal IR injury in a long-term experiment. Wistar rats (n = 36) were divided into 4 experimental groups (IR 10 , IR 20 , IR 30 , S). Groups IR 10 , IR 20 and IR 30 (each n = 10) were subjected to 1-hour ischaemia of the cranial mesenteric artery followed by 10, 20 or 30 days of reperfusion, respectively. The control group S (n = 6) was not subjected to ischaemia. The jejunal mucosa remained intact after all periods of reperfusion. Apoptotic cells were found particularly in the lamina propria, with the most significant difference observed in the IR 30 group (P < 0.01). The lung parenchyma had lower regenerative capacity, which was confirmed by a high index of histological damage after 30 days of reperfusion (P < 0.01) and by the presence of an increased number of apoptotic cells, especially in the pulmonary interstitium. The number of apoptotic cells was ten times higher than in the control group (P < 0.001).

Role of the renin-angiotensin system in the development of thyroxine-induced hypertension

1997 ◽  
Vol 136 (6) ◽  
pp. 656-660 ◽  
Author(s):  
Cipriano Garcia del Rio ◽  
María Rosario R Moreno ◽  
Antonio Osuna ◽  
Juan de Dios Luna ◽  
Joaquín García-Estañ ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Hypertrophy ◽  
Tap Water ◽  
Weight Ratio ◽  
Renin Angiotensin System ◽  
Control Group ◽  
Angiotensin System ◽  
Renin Angiotensin

Abstract Objective: We evaluated the influence of chronic blockade of the renin-angiotensin system on hypertension induced by long-term thyroxine (T4) administration. To this end, we determined the effects of chronic treatment with captopril on blood pressure, cardiac hypertrophy and other renal and metabolic variables of hypertensive hyperthyroid rats. Methods: T4 was administered s.c. at 0·38 μmol/kg per day and captopril was given in the drinking water (1·38 mmol/l). Both treatments were maintained for 6 weeks. Control rats received tap water. After the treatment period, the rats were placed in metabolic cages. Later, blood pressure was measured in conscious rats by intra-arterial determination. Results: T4-treated rats showed an increased mean arterial pressure (MAP) whereas, in rats treated with T4 plus captopril, MAP was similar to that of the control group. Captopril did not affect the increased heart rate or ventricular weight/body weight ratio of hyperthyroid rats, but it improved the reduced creatinine clearance of these animals. Conclusions: The elevation in blood pressure produced by long-term T4 administration was prevented by chronic blockade of the renin-angiotensin system. Captopril improved the renal function of hyperthyroid rats, but did not affect the relative cardiac hypertrophy of these animals. European Journal of Endocrinology 136 656–660

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