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Medicine and Science in Sports and... Dec 2010The introduction of molecular biology to thermoregulation was delayed compared with its application in other research fields pertinent to human health and disease. Using... (Review)
Review
The introduction of molecular biology to thermoregulation was delayed compared with its application in other research fields pertinent to human health and disease. Using principles from molecular biology, we revisited fundamental problems in integrative and environmental physiology and were able to explore new research horizons. Global genomic responses in tandem with an appropriate physiological experimental model are a good experimental design strategy that can unravel the molecular mechanisms underlying integrative thermoregulatory responses. In this way, dynamic adaptation models, with accentuated or diminished regulatory circuits, triggered by superimposition of novel stressors sharing similar protective pathways, have significant benefits. On the basis of this approach, we will discuss the molecular physiological linkage of heat acclimation alone or combined with exercise training and decipher stress-specific genes in the thermoregulatory circuits in the heart and skeletal muscles. Opposing/competing adaptive features are required for each of the above-mentioned physiological conditions. Aerobic training increases the capacity to store/use ATP. In contrast, the acclimated phenotype attempts to counteract excessive heat production. Nevertheless, both treatments augment muscle force generation. These changes are tissue-specific; in the exercise-trained rat heart, there is up-regulation of Ca2+-induced Ca2+ release mechanism genes, whereas in the skeletal muscle (soleus), the enrichment is found in genes involved in metabolism. The final issue discussed in this review is the possibility that heat shock proteins serve as consensus markers of heat stress. The role of the autonomic nervous system in their induction during heat stress and how they affect integrative body systems are described.
Topics: Acclimatization; Animals; Body Temperature Regulation; Gene Expression; Gene Expression Profiling; HSP72 Heat-Shock Proteins; Hot Temperature; Israel; Muscle, Skeletal; Phenotype; Rats
PubMed: 20404766
DOI: 10.1249/MSS.0b013e3181e303b0 -
International Journal of Molecular... Dec 2021Epigenetic modifications, including chromatin modifications and DNA methylation, play key roles in regulating gene expression in both plants and animals. Transmission of... (Review)
Review
Epigenetic modifications, including chromatin modifications and DNA methylation, play key roles in regulating gene expression in both plants and animals. Transmission of epigenetic markers is important for some genes to maintain specific expression patterns and preserve the status quo of the cell. This article provides a review of existing research and the current state of knowledge about DNA methylation in trees in the context of global climate change, along with references to the potential of epigenome editing tools and the possibility of their use for forest tree research. Epigenetic modifications, including DNA methylation, are involved in evolutionary processes, developmental processes, and environmental interactions. Thus, the implications of epigenetics are important for adaptation and phenotypic plasticity because they provide the potential for tree conservation in forest ecosystems exposed to adverse conditions resulting from global warming and regional climate fluctuations.
Topics: Acclimatization; Animals; Climate Change; DNA Methylation; Ecosystem; Forests; Gene Expression; Humans; Trees
PubMed: 34948318
DOI: 10.3390/ijms222413524 -
British Journal of Sports Medicine Dec 2013Team sports are increasingly popular, with millions of participants worldwide. Athletes engaged in these sports are required to repeatedly produce skilful actions and... (Review)
Review
Team sports are increasingly popular, with millions of participants worldwide. Athletes engaged in these sports are required to repeatedly produce skilful actions and maximal or near-maximal efforts (eg, accelerations, changes in pace and direction, sprints, jumps and kicks), interspersed with brief recovery intervals (consisting of rest or low-intensity to moderate-intensity activity), over an extended period of time (1-2 h). While performance in most team sports is dominated by technical and tactical proficiencies, successful team-sport athletes must also have highly-developed, specific, physical capacities. Much effort goes into designing training programmes to improve these physical capacities, with expected benefits for team-sport performance. Recently, some team sports have introduced altitude training in the belief that it can further enhance team-sport physical performance. Until now, however, there is little published evidence showing improved team-sport performance following altitude training, despite the often considerable expense involved. In the absence of such studies, this review will identify important determinants of team-sport physical performance that may be improved by altitude training, with potential benefits for team-sport performance. These determinants can be broadly described as factors that enhance either sprint performance or the ability to recover from maximal or near-maximal efforts. There is some evidence that some of these physical capacities may be enhanced by altitude training, but further research is required to verify that these adaptations occur, that they are greater than what could be achieved by appropriate sea-level training and that they translate to improved team-sport performance.
Topics: Acclimatization; Adenosine Triphosphate; Altitude; Athletic Performance; Buffers; Energy Metabolism; Group Processes; Humans; Muscle Strength; Muscle, Skeletal; Oxygen Consumption; Phosphocreatine; Psychomotor Performance; Running
PubMed: 24282200
DOI: 10.1136/bjsports-2013-092950 -
Methods in Molecular Biology (Clifton,... 2024Temporary immersion systems (TIS) are technological tools that support plant micropropagation. Given their high efficiency in the in vitro propagation of shoots, a...
Temporary immersion systems (TIS) are technological tools that support plant micropropagation. Given their high efficiency in the in vitro propagation of shoots, a current goal is to update the protocols addressing micropropagation in semisolid culture systems to protocols involving TIS. To this end, different parameters have been evaluated, including TIS types and designs, immersion times, immersion frequencies, and volume of medium per explant, among other characteristics. This has resulted in the improved production of propagules of plants of economic interest and the production of physiologically upgraded plants with high percent survival during acclimatization. TIS are specialized culture flasks that provide countless advantages during the commercial micropropagation of plants.
Topics: Immersion; Acclimatization; Reproduction; Technology
PubMed: 38285134
DOI: 10.1007/978-1-0716-3654-1_1 -
Clinical Trials (London, England) Jun 2021This article describes the proposed design of a phase I study evaluating the safety of ceramide nanoliposome and vinblastine among an initial set of 19 possible dose...
BACKGROUND/AIMS
This article describes the proposed design of a phase I study evaluating the safety of ceramide nanoliposome and vinblastine among an initial set of 19 possible dose combinations in patients with relapsed/refractory acute myeloid leukemia and patients with untreated acute myeloid leukemia who are not candidates for intensive induction chemotherapy.
METHODS
Extensive collaboration between statisticians and clinical investigators revealed the need to incorporate several adaptive features into the design, including the flexibility of adding or eliminating certain dose combinations based on safety criteria applied to multiple dose pairs. During the design stage, additional dose levels of vinblastine were added, increasing the dimension of the drug combination space and thus the complexity of the problem. Increased complexity made application of existing drug combination dose-finding methods unsuitable in their current form.
RESULTS
Our solution to these challenges was to adapt a method based on isotonic regression to meet the research objectives of the study. Application of this adapted method is described herein, and a simulation study of the design's operating characteristics is conducted.
CONCLUSION
The aim of this article is to bring to light examples of novel design applications as a means of augmenting the implementation of innovative designs in the future and to demonstrate the flexibility of adaptive designs in satisfying changing design conditions.
Topics: Adaptive Clinical Trials as Topic; Clinical Trials, Phase I as Topic; Computer Simulation; Dose-Response Relationship, Drug; Drug Combinations; Humans; Leukemia, Myeloid, Acute; Maximum Tolerated Dose; Research Design
PubMed: 33426919
DOI: 10.1177/1740774520983484 -
British Journal of Sports Medicine Dec 2013Despite the limited research on the effects of altitude (or hypoxic) training interventions on team-sport performance, players from all around the world engaged in these...
Despite the limited research on the effects of altitude (or hypoxic) training interventions on team-sport performance, players from all around the world engaged in these sports are now using altitude training more than ever before. In March 2013, an Altitude Training and Team Sports conference was held in Doha, Qatar, to establish a forum of research and practical insights into this rapidly growing field. A round-table meeting in which the panellists engaged in focused discussions concluded this conference. This has resulted in the present position statement, designed to highlight some key issues raised during the debates and to integrate the ideas into a shared conceptual framework. The present signposting document has been developed for use by support teams (coaches, performance scientists, physicians, strength and conditioning staff) and other professionals who have an interest in the practical application of altitude training for team sports. After more than four decades of research, there is still no consensus on the optimal strategies to elicit the best results from altitude training in a team-sport population. However, there are some recommended strategies discussed in this position statement to adopt for improving the acclimatisation process when training/competing at altitude and for potentially enhancing sea-level performance. It is our hope that this information will be intriguing, balanced and, more importantly, stimulating to the point that it promotes constructive discussion and serves as a guide for future research aimed at advancing the bourgeoning body of knowledge in the area of altitude training for team sports.
Topics: Acclimatization; Altitude; Athletic Performance; Atmospheric Pressure; Competitive Behavior; Exercise; Exercise Tolerance; Forecasting; Group Processes; Humans; Hypoxia; Professional Practice; Sleep; Sports Medicine
PubMed: 24282213
DOI: 10.1136/bjsports-2013-093109 -
High Altitude Medicine & Biology 2001Many physiological and anthropological studies have investigated the unique Andean and Himalayan populations that have resided for many hundreds of generations at high... (Review)
Review
Many physiological and anthropological studies have investigated the unique Andean and Himalayan populations that have resided for many hundreds of generations at high altitude (HA). A nonscientific survey of the extant literature reveals a relatively liberal tradition of inferring genetic (evolutionary) adaptation to HA in these groups, often based on limited evidence and/or based on study designs insufficient to fully address the issue. In order to provide some perspective, I review relevant methodological issues that should be considered before evolutionary inference is made. On the whole, this paper takes a conservative stance and cautions against evolutionary inference based on the serious limitations of currently applied research approaches.
Topics: Acclimatization; Altitude; Asian People; Chile; Confounding Factors, Epidemiologic; Ethnicity; Humans; Hypoxia; Nepal; Selection, Genetic
PubMed: 11443002
DOI: 10.1089/152702901750265314 -
The New Phytologist Feb 2021While Arabidopsis seed coat epidermal cells have become an excellent genetic system to study the biosynthesis and structural roles of various cell wall polymers, the...
While Arabidopsis seed coat epidermal cells have become an excellent genetic system to study the biosynthesis and structural roles of various cell wall polymers, the physiological function of the secreted mucilaginous polysaccharides remains ambiguous. Seed mucilage is shaped by two distinct classes of highly substituted hemicelluloses along with cellulose and structural proteins, but their interplay has not been explored. We deciphered the functions of four distinct classes of cell wall polymers by generating a series of double mutants with defects in heteromannan, xylan, cellulose, or the arabinogalactan protein SALT-OVERLY SENSITIVE 5 (SOS5), and evaluating their impact on mucilage architecture and seed germination during salt stress. We discovered that muci10 seeds, lacking heteromannan branches, had elevated tolerance to salt stress, while heteromannan elongation mutants exhibited reduced germination in calcium chloride (CaCl ). By contrast, xylan made by MUCILAGE-RELATED21 (MUCI21) was found to be required for the adherence of mucilage pectin to microfibrils made by CELLULOSE SYNTHASE5 (CESA5) as well as to a SOS5-mediated network. Our results indicate that the substitution of xylan and glucomannan in seeds can fine-tune mucilage adherence and salt tolerance, respectively. The study of germinating seeds can thus provide insights into the synthesis, modification and function of complex glycans.
Topics: Arabidopsis Proteins; Cell Wall; Polysaccharides; Salt Tolerance; Seeds
PubMed: 33128402
DOI: 10.1111/nph.17056 -
Comparative Biochemistry and... Aug 2002Studies in the laboratory with salmonids and now in the field with wild salmon clearly show that critical swimming performance has an optimum temperature. This... (Comparative Study)
Comparative Study Review
Studies in the laboratory with salmonids and now in the field with wild salmon clearly show that critical swimming performance has an optimum temperature. This temperature optimum is coincident with maximum aerobic scope and maximum cardiac scope. At a temperature that is higher than this optimum, however, whole animal performance declines abruptly. Evidence is presented here to suggest that this is directly associated with a decline in cardiac scope which limits oxygen supply to tissues. It is further suggested that the decline in maximum cardiac performance could reflect problems with the heart's own oxygen supply. The reasoning behind this suggestion is that, at temperatures at or below the optimum and probably because of a limitation on oxygen diffusion in skeletal muscle during exercise, venous oxygen does not fall below a threshold level during exercise, and so the heart receives just enough oxygen for its own muscular activity via the cardiac circulation (i.e. the venous return to the heart). However, because high temperature favours increased oxygen extraction by skeletal muscle, which consequently lowers venous oxygen, cardiac oxygen supply may become insufficient to meet cardiac oxygen demand. The hypoxic myocardium then cannot maintain cardiac scope and internal oxygen delivery to tissue declines.
Topics: Acclimatization; Animals; Cardiovascular Physiological Phenomena; Hot Temperature; Hypoxia; In Vitro Techniques; Muscle, Skeletal; Oxygen; Oxygen Consumption; Physical Exertion; Respiratory Physiological Phenomena; Salmonidae
PubMed: 12095864
DOI: 10.1016/s1095-6433(02)00049-1 -
International Journal of Circumpolar... Jun 2010To review the current literature that describes the effect of Antarctic residence on energy dynamics and aerobic fitness. (Review)
Review
OBJECTIVE
To review the current literature that describes the effect of Antarctic residence on energy dynamics and aerobic fitness.
STUDY DESIGN
Literature review.
METHODS
Published literature on energy dynamics and aerobic fitness in the polar environment was reviewed. Energy dynamics were represented by body weight, body fat, food intake and energy expenditure. Consideration was given to seasonal variation and possible explanations for the apparent high metabolic cost of Antarctic residence. The influence of cold exposure was discussed and comment was made on the differences between temperate and polar residence.
RESULTS
Food intake and energy expenditure are found to increase with Antarctic residence. There is often an associated increase in body weight and body fat. Seasonal variation is common but not universal, with an increase in body weight and body fat in winter. Variation in aerobic fitness appears to be related to the specific study sample rather than Antarctic residence per se.
CONCLUSIONS
In most instances, Antarctic residence has effects on energy dynamics and aerobic fitness. Explanations for the observed changes may include physiological adaptations, such as a raised basal metabolic rate and increased thermogenesis. However, cold-induced changes are less likely when cold exposure is minimized by heated buildings and insulated clothing. Activity patterns related to work and leisure thus represent a more likely cause. The majority of the research is several decades old; further research would help to elucidate the patterns of energy dynamics of modern Antarctic workers.
Topics: Acclimatization; Antarctic Regions; Body Weight; Cold Climate; Energy Intake; Energy Metabolism; Humans; Physical Fitness; Seasons
PubMed: 20519091
DOI: 10.3402/ijch.v69i3.17625