336 research outputs found

    Substrate Use and Biochemical Response to a 3,211-km Bicycle Tour in Trained Cyclists

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    The purpose of this study was to assess the physiological adaptations in physically fit individuals to a period of intensified training. Ten trained males cycled outdoors ~170 km day−1 on 19 out of 21 days. Expired gas was collected on days 1 and 21 during maximal graded exercise and used for the determination of gross efficiency and whole body substrate use. Muscle biopsies were obtained before and after exercise on days 2 and 22 for the determination of mtDNA/gDNA ratio, gene expression, metabolic enzyme activity and glycogen use. Muscle glycogen before and after exercise, fat oxidation, and gross efficiency increased, carbohydrate oxidation decreased (p \u3c 0.05), and VO2max did not change over the 21 days of training. Citrate synthase (CS), β-hydroxyacyl CoA dehydrogenase (β-HAD) and cytochrome c oxidase (COX) enzyme activity did not change with training. CS and β-HAD mRNA did not change with acute exercise or training. COX (subunit IV) mRNA increased with acute exercise (p \u3c 0.05) but did not change over the 21 days. PGC-1α mRNA increased with acute exercise, but did not increase to the same degree on day 22 as it did on day 2 (p \u3c 0.05). UCP3 mRNA decreased with training (p \u3c 0.05). Acute exercise caused an increase in mitofusin2 (MFN2) mRNA (p \u3c 0.05) and a trend for an increase in mtDNA/gDNA ratio (p = 0.057). However, training did not affect MFN2 mRNA or mtDNA/gDNA ratio. In response to 3,211 km of cycling, changes in substrate use and gross efficiency appear to be more profound than mitochondrial adaptations in trained individuals

    Metabolic Profile of the Ironman World Championships: A Case Study

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    Purpose: The purpose of this study was to determine the metabolic profile during the 2006 Ironman World Championship in Kailua-Kona, Hawaii. Methods: One recreational male triathlete completed the race in 10:40:16. Before the race, linear regression models were established from both laboratory and field measures to estimate energy expenditure and substrate utilization. The subject was provided with an oral dose of (2)H(2)(18)O approximately 64 h before the race to calculate total energy expenditure (TEE) and water turnover with the doubly labeled water (DLW) technique. Body weight, blood sodium and hematocrit, and muscle glycogen (via muscle biopsy) were analyzed pre- and postrace. Results: The TEE from DLW and indirect calorimetry was similar: 37.3 MJ (8,926 kcal) and 37.8 MJ (9,029 kcal), respectively. Total body water turnover was 16.6 L. and body weight decreased 5.9 kg. Hematocrit increased from 46 to 51% PCV. Muscle glycogen decreased from 152 to 48 mmoL/kg wet weight pre- to postrace. Conclusion: These data demonstrate the unique physiological demands of the Ironman World Championship and should be considered by athletes and coaches to prepare sufficient nutritional and hydration plans

    Effects on Oxygen Consumption and Metabolic Gene Expression when Determining Experimental Exercise Intensity Based on Exercise Capacity Tests Conducted in Hypoxic and Normoxic Environments

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    Abstract: Exercise intensity can be set relative to VO2 max measured during hypoxic or control conditions in studies investigating exercise in hypoxic environments. It currently is not clear which is the most appropriate method. Objective: The objective of this brief report is to determine the response to 1 hour of cycling at 60% of peak power when measured in either normoxic or hypoxic conditions. Methods: Eleven recreationally active male participants (24 ± 4 yrs, 173 ± 20 cm, 82 ± 12 kg, 15.2 ± 7.1% fat, 4.0 ± 0.6 L x min-1 VO2 max) completed two 1 hour cycling exercise trials at 60% of peak power followed by 4 hours of recovery in ambient environmental conditions (975 m) and at normobaric hypoxic conditions simulating 3000 m in a randomized counter balanced order. Results: VO2 max was not different between trials in relative (p=0.272) or absolute terms (p=0.105) but peak power at VO2 max was higher in the 975 m trial (288 ± 17 watts) than the 3000 m trial (262 ± 12 watts, p=0.003) corresponding to differences at 60% of VO2 max power. Gene expression of HIF-1α, COX, PGC-1α, HK, and PFK increased with exercise (p\u3c0.05) but did not differ between trials. There was a trend (p=0.072) toward increased muscle glycogen use in 975m. Conclusions: Although there were not statistical differences for muscle markers in the current study, these data should be considered when determining exercise intensity in hypoxia related research

    Intershock observations during STIP intervals 17 and 18

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    The Prognoz-10/Intercosmos satellite (Intershock Project) carried out observations from Earth orbit from 26 April 1985 until 11 November 1985, covering STIP Intervals XVII and XVIII. Data obtained during the systematic measurements in the course of STIP Interval XVII and part of XVIII are presented; i.e., hourly averages of the solar wind velocity, temperature and ion concentration, ion flux changes (10 to the -1 to 10 to the -3 Hz), plasma wave parameters, energetic particles flux, magnetic fields, etc. Special attention is paid to solar wind distrubances causing abrupt and large effects on the shape of the bow shock (i.e., on 2 May 1985 and 14 September 1985). Generally, the observation period was very close to a minimum of solar activity and was quiet without significant interplanetary shocks

    Applying of Monte-Carlo simulations for in-situ gamma spectrometry

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    Kako bi se dobile krive efikasnosti detekcije za In-situ merenja gama zračenja poreklom iz zemljišta, potrebno je izvršiti odgovarajuće Monte-Karlo simulacije. U simulacijama je korišćena gustina zemljišta od 1,046 g/cm3 , dok je elementalni sastav zemljišta u kojem se generiše gama zračenje bio: O - 47%, Si - 35%, Al - 8%, Fe – 3,9%, C – 2,1%, Ca – 1,4%, K – 1,3%, N – 0,6%, Mg – 0,6%, N – 0,1%. Matrica zemljišta je predstavljena cilindričnom zapreminom prečnika 1,5 m i debljine 0,5 m, iznad koje je na visini od 1 m postavljen germanijumski detektor. Razmatrane su homogene distribucije različitih radionuklida (Ra-226, Th-232, K-40) u matrici zemljišta. U simulacijama su dobijeni i analizirani odgovarajući gama spektri, koji uz podatke o simuliranim efikasnostima detekcije, omogućuju poređenje sa realnim eksperimentalnim merenjima i praktičnu primenu simulacionih rezultata.In this work, the Monte-Carlo simulations for In-Situ gamma spectrometry of soil were performed. The simulated gamma spectrum, originated from K-40, as well as from members of Th-232 chain, and daughters of Ra-226, was obtained. We obtained the corresponding detection efficiency curve for HPGe detector, which can be applied for In-Situ measurement of radionuclide concentration in soil, assuming uniform radionuclide distribution.Зборник радова : XXIX симпозијум ДЗЗСЦГ : Сребрно језеро, 27-29. септембар 2017. годин

    Applying of Monte-Carlo simulations for in-situ gamma spectrometry

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    Kako bi se dobile krive efikasnosti detekcije za In-situ merenja gama zračenja poreklom iz zemljišta, potrebno je izvršiti odgovarajuće Monte-Karlo simulacije. U simulacijama je korišćena gustina zemljišta od 1,046 g/cm3 , dok je elementalni sastav zemljišta u kojem se generiše gama zračenje bio: O - 47%, Si - 35%, Al - 8%, Fe – 3,9%, C – 2,1%, Ca – 1,4%, K – 1,3%, N – 0,6%, Mg – 0,6%, N – 0,1%. Matrica zemljišta je predstavljena cilindričnom zapreminom prečnika 1,5 m i debljine 0,5 m, iznad koje je na visini od 1 m postavljen germanijumski detektor. Razmatrane su homogene distribucije različitih radionuklida (Ra-226, Th-232, K-40) u matrici zemljišta. U simulacijama su dobijeni i analizirani odgovarajući gama spektri, koji uz podatke o simuliranim efikasnostima detekcije, omogućuju poređenje sa realnim eksperimentalnim merenjima i praktičnu primenu simulacionih rezultata.In this work, the Monte-Carlo simulations for In-Situ gamma spectrometry of soil were performed. The simulated gamma spectrum, originated from K-40, as well as from members of Th-232 chain, and daughters of Ra-226, was obtained. We obtained the corresponding detection efficiency curve for HPGe detector, which can be applied for In-Situ measurement of radionuclide concentration in soil, assuming uniform radionuclide distribution.Зборник радова : XXIX симпозијум ДЗЗСЦГ : Сребрно језеро, 27-29. септембар 2017. годин

    Quality of Life in Chronic Pancreatitis is Determined by Constant Pain, Disability/Unemployment, Current Smoking, and Associated Co-Morbidities

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    OBJECTIVES: Chronic pancreatitis (CP) has a profound independent effect on quality of life (QOL). Our aim was to identify factors that impact the QOL in CP patients. METHODS: We used data on 1,024 CP patients enrolled in the three NAPS2 studies. Information on demographics, risk factors, co-morbidities, disease phenotype, and treatments was obtained from responses to structured questionnaires. Physical and mental component summary (PCS and MCS, respectively) scores generated using responses to the Short Form-12 (SF-12) survey were used to assess QOL at enrollment. Multivariable linear regression models determined independent predictors of QOL. RESULTS: Mean PCS and MCS scores were 36.7+/-11.7 and 42.4+/-12.2, respectively. Significant (P \u3c 0.05) negative impact on PCS scores in multivariable analyses was noted owing to constant mild-moderate pain with episodes of severe pain or constant severe pain (10 points), constant mild-moderate pain (5.2), pain-related disability/unemployment (5.1), current smoking (2.9 points), and medical co-morbidities. Significant (P \u3c 0.05) negative impact on MCS scores was related to constant pain irrespective of severity (6.8-6.9 points), current smoking (3.9 points), and pain-related disability/unemployment (2.4 points). In women, disability/unemployment resulted in an additional 3.7 point reduction in MCS score. Final multivariable models explained 27% and 18% of the variance in PCS and MCS scores, respectively. Etiology, disease duration, pancreatic morphology, diabetes, exocrine insufficiency, and prior endotherapy/pancreatic surgery had no significant independent effect on QOL. CONCLUSIONS: Constant pain, pain-related disability/unemployment, current smoking, and concurrent co-morbidities significantly affect the QOL in CP. Further research is needed to identify factors impacting QOL not explained by our analyses

    Interobserver agreement for single operator choledochoscopy imaging: can we do better?

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    Background. The SpyGlass Direct Visualization System (Boston Scientific, Natick, MA) is routinely used during single operator choledochoscopy (SOC) to identify biliary lesions or strictures with a diagnostic accuracy up to 88%. The objective of this study was to determine the interobserver agreement (IOA) of modified scoring criteria for diagnosing biliary lesions/strictures. Methods. 27 SPY SOC video clips were reviewed and scored by 9 interventional endoscopists based on published criteria that included the presence and severity of surface structure, vasculature visualization, lesions, and findings. Results. Overall IOA was slight for all variables. The K statistics are as follows: surface (K = 0.12, SE = 0.02); vessels (K = 0.14, SE = 0.02); lesions (K = 0.11, SE = 0.02); findings (K = 0.08, SE = 0.03); and final diagnosis (K = 0.08, SE = 0.02). The IOA for findings and final diagnosis was also only slight. The final diagnosis was malignant (11), benign (11), and indeterminate (5). Conclusion. IOA using the modified criteria of SOC images was slight to almost poor. The average accuracy was less than 50%. These findings reaffirm that imaging criteria for benign and malignant biliary pathology need to be formally established and validated

    Use and perceived effectiveness of non-analgesic medical therapies for chronic pancreatitis in the United States

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    Aliment Pharmacol Ther 2011; 33: 149–159Effectiveness of medical therapies in chronic pancreatitis has been described in small studies of selected patients.To describe frequency and perceived effectiveness of non-analgesic medical therapies in chronic pancreatitis patients evaluated at US referral centres.Using data on 516 chronic pancreatitis patients enrolled prospectively in the NAPS2 Study, we evaluated how often medical therapies [pancreatic enzyme replacement therapy (PERT), vitamins/antioxidants (AO), octreotide, coeliac plexus block (CPB)] were utilized and considered useful by physicians.Oral PERT was commonly used (70%), more frequently in the presence of exocrine insufficiency (EI) (88% vs. 61%, P  < 0.001) and pain (74% vs. 59%, P  < 0.002). On multivariable analyses, predictors of PERT usage were EI (OR 5.14, 95% CI 2.87–9.18), constant (OR 3.42, 95% CI 1.93–6.04) or intermittent pain (OR 1.98, 95% CI 1.14–3.45). Efficacy of PERT was predicted only by EI (OR 2.16, 95% CI 1.36–3.42). AO were tried less often (14%) and were more effective in idiopathic and obstructive vs. alcoholic chronic pancreatitis (25% vs. 4%, P  = 0.03). Other therapies were infrequently used (CPB – 5%, octreotide – 7%) with efficacy generally <50%.Pancreatic enzyme replacement therapy is commonly utilized, but is considered useful in only subsets of chronic pancreatitis patients. Other medical therapies are used infrequently and have limited efficacy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79114/1/j.1365-2036.2010.04491.x.pd
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