scholarly journals Features of Metabolic Support of Physical Performance in Highly Trained Cross-Country Skiers of Different Qualifications during Physical Activity at Maximum Load

Cells ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 39
Author(s):  
Olga I. Parshukova ◽  
Nina G. Varlamova ◽  
Natalya N. Potolitsyna ◽  
Aleksandra Y. Lyudinina ◽  
Evgeny R. Bojko
Keyword(s):  
Metabolic Regulation ◽  
Molecular Mechanisms ◽  
Maximum Load ◽  
Bicycle Ergometer ◽  
Cycle Ergometer ◽  
Serum Lactate ◽  
Load Test ◽  
National Team ◽  
Group I ◽  
Cross Country

The purpose of our study was to identify the features of metabolic regulation in highly trained cross-country skiers of different qualifications at different stages of the maximum load test. We examined 124 highly trained cross-country skiers (male, ages 17–24). The group consisted of two subgroups based on their competition performance: 61 nonelite athletes (Group I) and 63 elite athletes (group II), who were current members of the national team of the Komi Republic and Russia. The bicycle ergometer test was performed by using the OxyconPro system (Erich Jaeger, Hoechberg, Germany). All the examined athletes performed the exercise test on a cycle ergometer “until exhaustion”. The results of our research indicate that the studied groups of athletes with high, but different levels of sports qualifications are a convenient model for studying the molecular mechanisms of adaptation to physical loads of maximum intensity. Athletes of higher qualifications reveal additional adaptive mechanisms of metabolic regulation, which is manifested in the independence of serum lactate indicators under conditions of submaximal and maximum power from maximal oxygen uptake, and they have an NO-dependent mechanism for regulating lactate levels during aerobic exercise, including work at the anaerobic threshold.

scholarly journals Nitric Oxide Production in Professional Skiers During Physical Activity at Maximum Load

2020 ◽  
Vol 7 ◽  
Author(s):  
Olga I. Parshukova ◽  
Nina G. Varlamova ◽  
Evgeny R. Bojko
Keyword(s):  
Physical Activity ◽  
Nitric Oxide ◽  
Blood Pressure ◽  
Exercise Test ◽  
Recovery Period ◽  
Maximum Load ◽  
Cycle Ergometer ◽  
Response To Stress ◽  
Cross Country ◽  
Nitric Oxide Metabolites

The purpose of this study is to assess the production of nitric oxide in professional cross-country skiers with normotensive and hypertensive responses to physical activity at maximum load. The observation group included professional cross-country skiers (22.2 ± 7.1 years, = 107) who were current members of the national team of the Komi Republic. All the examined athletes performed the exercise test on a cycle ergometer “until exhaustion.” The following parameters were determined for each participant while they were sitting at rest, while at their anaerobic threshold level, during peak load, and during the recovery period (5th min): systolic blood pressure, diastolic blood pressure, heart rate, and the level of stable nitric oxide metabolites (nitrites, nitrates) in capillary blood samples. According to the blood pressure results, the cross-country skiers were divided into two groups. Group I included athletes with a normotensive response to stress. Group II was composed of individuals with a hypertensive response to stress. During the performance of the test “until exhaustion,” a significant (p < 0.05) increase in the amount of stable metabolites of nitric oxide was observed in the group of athletes with a normotensive response to the load compared with the group with a hypertensive response to the load. In athletes with a normotensive reaction to the load during exercise at maximum load and in the early recovery period, nitrate was prioritized in the regulation of vascular tone. The exercise test on a cycle ergometer “until exhaustion,” combined with the assessment of the levels of stable nitric oxide metabolites in plasma, can be considered a test for the early diagnosis of endothelial dysfunction in professional athletes.

scholarly journals Analýza zátěžových testů u skialpinistů

2012 ◽  
Vol 6 (1) ◽  
pp. 29-34
Author(s):  
Matouš Jindra ◽  
Ladislav Vomáčko ◽  
Dita Formánková ◽  
Klára Coufalová
Keyword(s):  
Maximum Stress ◽  
Stress Test ◽  
Maximum Load ◽  
Bicycle Ergometer ◽  
Load Test ◽  
Previous Experience ◽  
Stress Tests ◽  
Professional Information

We analyze 3 types of maximum stress tests on the basis of the lack of professional information about competitive ski mountaineering. Th e obtained data was compared with the maximum stress test on the treadmill; bicycle ergometer and treadmill using a roller ski modifi ed for ski mountaineering. Th e values which were measured shows great technical demands on the test using roller skis. Based on this information, we recommend long-term training on the treadmill using roller skis, before the maximum load test. Th e results show the smallest deviation of the maximum values among respondents who had previous experience with modifi ed roller skis for ski mountaineering.

scholarly journals Hypoxic tumor microenvironment: Implications for cancer therapy

2020 ◽  
Vol 245 (13) ◽  
pp. 1073-1086
Author(s):  
Sukanya Roy ◽  
Subhashree Kumaravel ◽  
Ankith Sharma ◽  
Camille L Duran ◽  
Kayla J Bayless ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Metabolic Regulation ◽  
Molecular Mechanisms ◽  
Hypoxia Inducible Factor ◽  
Tumor Vasculature ◽  
Therapeutic Strategies ◽  
Therapeutic Resistance ◽  
Low Oxygen ◽  
Cancer Types

Hypoxia or low oxygen concentration in tumor microenvironment has widespread effects ranging from altered angiogenesis and lymphangiogenesis, tumor metabolism, growth, and therapeutic resistance in different cancer types. A large number of these effects are mediated by the transcription factor hypoxia inducible factor 1⍺ (HIF-1⍺) which is activated by hypoxia. HIF1⍺ induces glycolytic genes and reduces mitochondrial respiration rate in hypoxic tumoral regions through modulation of various cells in tumor microenvironment like cancer-associated fibroblasts. Immune evasion driven by HIF-1⍺ further contributes to enhanced survival of cancer cells. By altering drug target expression, metabolic regulation, and oxygen consumption, hypoxia leads to enhanced growth and survival of cancer cells. Tumor cells in hypoxic conditions thus attain aggressive phenotypes and become resistant to chemo- and radio- therapies resulting in higher mortality. While a number of new therapeutic strategies have succeeded in targeting hypoxia, a significant improvement of these needs a more detailed understanding of the various effects and molecular mechanisms regulated by hypoxia and its effects on modulation of the tumor vasculature. This review focuses on the chief hypoxia-driven molecular mechanisms and their impact on therapeutic resistance in tumors that drive an aggressive phenotype. Impact statement Hypoxia contributes to tumor aggressiveness and promotes growth of many solid tumors that are often resistant to conventional therapies. In order to achieve successful therapeutic strategies targeting different cancer types, it is necessary to understand the molecular mechanisms and signaling pathways that are induced by hypoxia. Aberrant tumor vasculature and alterations in cellular metabolism and drug resistance due to hypoxia further confound this problem. This review focuses on the implications of hypoxia in an inflammatory TME and its impact on the signaling and metabolic pathways regulating growth and progression of cancer, along with changes in lymphangiogenic and angiogenic mechanisms. Finally, the overarching role of hypoxia in mediating therapeutic resistance in cancers is discussed.

Lactate Clearance Versus Base Deficit Correction in Monotoring of Septic Shock

QJM ◽  
2021 ◽  
Vol 114 (Supplement_1) ◽  
Author(s):  
Adel Mikhail Fahmy ◽  
Ahmed Kamal ◽  
Wael Abd Elmonem Mohamed Abdelwahab ◽  
Ameer Shokry Ahmed
Keyword(s):  
Septic Shock ◽  
Clinical Utility ◽  
Tissue Perfusion ◽  
Lactate Clearance ◽  
Serum Lactate ◽  
Base Deficit ◽  
Mortality And Morbidity ◽  
Survivor Group ◽  
Prediction Of Mortality ◽  
Group I

Abstract Background Tissue perfusion and oxygenation monitoring is the fundamental of management to immediately identify and properly manage (impending) organ dysfunction in septic shock. This is a study of a prospective randomized trial that aims to comparing the prognostic value of lactate clearance versus base deficit correction as an indicator of tissue perfusion in septic shock, trying to prove the superiority of one over the other. Objective To assess the clinical utility of lactate clearance and arterial base deficit correction in predicting mortality in septic shock. Patients and Methods This is a Prospective randomized observational study that was conducted to assess the clinical utility of lactate clearance and arterial base deficit in predicting mortality in septic shock. This study included forty patients who were divided into two equal groups; each of twenty patients, group I (non-survivors), and group II (survivors). Results In this study, the base deficit values revealed statistically notable difference between the two groups at admission, 18 hours, 24 hours and 2 days of admission. The values revealed no notable difference at the 3rd. 4th, and 5th day of admission. At the 6th and 7th day of admission, the base deficit started to increase again in the non-survivor group with statistically notable increase in the values as compared to the survivor group. The cutoff point of base deficit to differentiate between nonsurvivors from survivors was > 11.43 with 62% sensitivity and 100% specificity. In this study, initial serum lactate levels at admission revealed higher accuracy in prediction of mortality as compared with initial base deficit. Conclusion Lactate clearance is a better predictor of mortality and morbidity than base deficit correction.

Geotechnical Investigation, Field Load Test and Analysis of Full-Scale Bored Pile

2015 ◽  
Vol 813-814 ◽  
pp. 1126-1130
Author(s):  
G. Kesavan ◽  
S.S. Chandrasekaran
Keyword(s):  
Tamil Nadu ◽  
Ground Level ◽  
Maximum Load ◽  
Field Investigation ◽  
Complex Problem ◽  
Load Test ◽  
Bored Pile ◽  
Economical Design ◽  
Pile Load Test ◽  
A Site

The maximum load carrying capacity of bored piles is a complex problem because it is a function of a number of factors, these factors include methods of soil exploration, ground water condition, types of grading of concrete, quantity and quality of concrete. The knowledge of Geotechnical test is important for the most economical design of the piles. This paper describes some important aspects of field investigation, design and construction of in-situ bored pile foundation, field pile load test of experience gained from the construction of the pile at a site in Aathoor in Tamil Nadu, India. The site was fully sandy soil from existing ground level. The design of bored pile under axial compression was done using Empirical formula, pile load test and by using PLAXIS 2D software. Results were compared with vertical load and settlement in this site.

Hormone metabolic pattern in the preclinical stage of preeclampsia

2021 ◽  
Vol 70 (3) ◽  
pp. 51-63
Author(s):  
Yury V. Tezikov ◽  
Igor S. Lipatov ◽  
Amir R. Azamatov
Keyword(s):  
Insulin Resistance ◽  
High Risk ◽  
Pregnant Women ◽  
Clinical Manifestation ◽  
Molecular Mechanisms ◽  
Vascular Endothelial Cell ◽  
Laboratory Examination ◽  
Preclinical Stage ◽  
Metabolic Pattern ◽  
Group I

BACKGROUND: The imbalance of vascular endothelial cell metabolism determines the clinical manifestations of preeclampsia; however, the molecular mechanisms underlying the vessel destabilization are not fully understood. In recent years, researchers have focused on clarifying the role of dysmetabolic disorders in patients with obstetric pathology, including preeclampsia. This is due to the fact that pregnancy is accompanied by metabolic restructuring aimed at switching the energy supply of the pregnant womans body from the carbohydrate to the fat component in order to maintain an effective energoplastic supply of the developing fetus. Impairment of this evolutionary adaptation mechanism realized during pregnancy requires additional in-depth study. AIM: This study was aimed to identify and compare pathogenetic patterns that characterize early and late preeclampsia at the preclinical stage, based on dynamic clinical and laboratory examination of high-risk pregnant women. MATERIALS AND METHODS: A prospective clinical and laboratory examination of 180 pregnant women with independent factors of high risk of developing preeclampsia was carried out. Comparison groups were identified retrospectively, depending on the period of preeclampsia manifestation: Group I consisted of 31 pregnant women with early preeclampsia; Group II comprised 58 pregnant women with late preeclampsia; and Group III (control) included 30 healthy pregnant women with uncomplicated gestation. Pregnant women were examined twice at the preclinical stage of preeclampsia (11-14 and 18-21 weeks of gestation) and once at clinical manifestation of the disease (28-36 weeks of gestation). The markers of metabolic, hormonal, hemocirculatory, hemostasiological and placental disorders were evaluated. RESULTS: We found similar pathophysiological changes in pregnant women with both early and late PE, from early gestation periods. Those were characterized by pathological insulin resistance and hyperinsulinemia, as well as associated atherogenic changes in the lipid profile, hyperleptinemia, hyperuricemia, hypersympathicotonia, visceral fat deposition, and contra-insular hormonal deviations. The observed alterations reflected a single hormonal and metabolic pattern of the preclinical stage of preeclampsia. During pregnancy, there was shown an increase in clustering diabetogenic and atherogenic abnormalities and hormonal changes, which were supplemented by associated endothelial and hemostasiological dysfunction and, in early preeclampsia, placental dysfunction, thus accelerating the time of clinical implementation of preeclampsia. CONCLUSIONS: From the pathogenetic point of view, preeclampsia of various periods of manifestation is an indivisible category with a common basic developmental mechanism characterized by a hormone metabolic pattern from the early stages of pregnancy. These stable changes are the result of the pathologically transformed phylogenetic mechanism of energoplastic supply of the fetus. This transformation is realized via physiological insulin resistance and compensatory hyperinsulinemia development due to the contra-insular activity of placental hormones. The added structural and functional disorders of the embryo (feto) placental system potentiate basic mechanisms (pathological insulin resistance and hyperinsulinemia) and determine the period of preeclampsia clinical manifestation in each particular woman.

Mechanisms linking energy balance and reproduction: impact of prenatal environment

2016 ◽  
Vol 25 (1) ◽  
Author(s):  
Erin M. Rhinehart
Keyword(s):  
Energy Balance ◽  
Metabolic Regulation ◽  
Developmental Plasticity ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Reproductive Fitness ◽  
Future Research ◽  
Energy Availability ◽  
Prenatal Environment ◽  
Regulation Of Reproduction

AbstractThe burgeoning field of metabolic reproduction regulation has been gaining momentum due to highly frequent discoveries of new neuroendocrine factors regulating both energy balance and reproduction. Universally throughout the animal kingdom, energy deficits inhibit the reproductive axis, which demonstrates that reproduction is acutely sensitive to fuel availability. Entrainment of reproductive efforts with energy availability is especially critical for females because they expend large amounts of energy on gestation and lactation. Research has identified an assortment of both central and peripheral factors involved in the metabolic regulation of reproduction. From an evolutionary perspective, these mechanisms likely evolved to optimize reproductive fitness in an environment with an unpredictable food supply and regular bouts of famine. To be effective, however, the mechanisms responsible for the metabolic regulation of reproduction must also retain developmental plasticity to allow organisms to adapt their reproductive strategies to their particular niche. In particular, the prenatal environment has emerged as a critical developmental window for programming the mechanisms responsible for the metabolic control of reproduction. This review will discuss the current knowledge about hormonal and molecular mechanisms that entrain reproduction with prevailing energy availability. In addition, it will provide an evolutionary, human life-history framework to assist in the interpretation of findings on gestational programming of the female reproductive function, with a focus on pubertal timing as an example. Future research should aim to shed light on mechanisms underlying the prenatal modulation of the adaptation to an environment with unstable resources in a way that optimizes reproductive fitness.

scholarly journals Load Carrying and Hydrostatic Performances of Innovative Encapsulated Anchorage System for Unbonded Single Strand

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Min Sook Kim ◽  
Young Hak Lee
Keyword(s):  
Stress Concentration ◽  
Transfer Test ◽  
Load Transfer ◽  
Maximum Load ◽  
Load Test ◽  
Static Load Test ◽  
Element Analysis ◽  
Bearing Plate ◽  
Anchorage System ◽  
Load Carrying

A new anchorage system is proposed having a circular bearing plate and curvature between the bearing plate and the anchor head to improve stress concentration. A lid with a screw instead of the grouting method is also proposed to prevent moisture penetration. The details of the anchorage device have been chosen to reduce stress concentration based on the finite element analysis. Static load test, load transfer test, and hydrostatic test of fabricated devices were carried out according to ETAG 013 to evaluate the proposed design. As results, the anchorage slip and stabilization satisfied the recommendations of ETAG 013. The maximum load in the load transfer test was at least 1.1 times the ultimate tendon strength. The results of the hydrostatic test showed that the developed anchorage device is watertight to protect against corrosion. As a result of bursting force test, it was confirmed that the proposed anchorage device has more advantages than the conventional rectangular anchorage devices in terms of stress distribution.

Structural Strength Evaluation of a Carbody by Finite Element Analysis and Load Test

2007 ◽  
Vol 353-358 ◽  
pp. 2728-2731 ◽  
Author(s):  
Sung Cheol Yoon ◽  
Chang Sung Jeon ◽  
Jeong Guk Kim
Keyword(s):  
Structural Analysis ◽  
Performance Test ◽  
Maximum Load ◽  
The Body ◽  
Load Test ◽  
Test Results ◽  
Body Structure ◽  
Loading Test ◽  
Element Analysis ◽  
Multiple Unit

This paper describes a carbody structural analysis and the result of its loading test. The purpose of this study is to evaluate the safety and functionality of the body structure operating under maximum load. Aluminum alloy was used as the body structure’s material. The body structure consisted of side frame, under frame, roof frame, and end frame. Of these components, the side frame and under frame were the most important components considering the vehicle and passenger loads. Both structural analysis and loading test were performed under the condition based on "Performance Test Standard for Electrical Multiple Unit" with the reference code JIS E 7105. The test results showed that the body structure is safe and stable under the condition of designed load.

A novel ceramic tibial component is as safe as its metal counterpart

2018 ◽  
Vol 63 (3) ◽  
pp. 327-332 ◽  
Author(s):  
Klemens Trieb
Keyword(s):  
Tibial Component ◽  
Maximum Load ◽  
Load Test ◽  
Strength Testing ◽  
Burst Strength ◽  
Total Knee ◽  
Material Fracture ◽  
Set Up ◽  
Further Development

Abstract Failure rates of 2–10% provide evidence for further development in knee arthroplasty. The purpose of our study was to examine the safety of the tibial component of a novel all-ceramic total knee replacement (TKR) (BPK-S Integration ceramic) consisting of BIOLOX®delta ceramic. The standards ISO 14879-1 and ASTM F1800-07 describe the test set-up for the experimental strength verification with a significantly increased maximum load of 5300 N (900 N are required) and post-fatigue burst strength testing. All specimens were able to prove their mechanical strength against fracture in the alternating load test. There was no material fracture in any of the included tibial components. The subsequent post-fatigue burst strength testing revealed the maximum strength against fracture of all specimens. With at least 9.7 kN for size 3 and at least 12.1 kN for size 6, all specimens showed relatively large strength reserves to the stress in the alternating load test. So far we simulated an in vivo lifetime of 10 years for the tibial component. Further studies should be conducted in which longer in vivo lifetimes of the components are simulated to investigate possible fatigue of the used material over a longer period of time.

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