The Experts below are selected from a list of 210 Experts worldwide ranked by ideXlab platform
John P. Kastelic - One of the best experts on this subject based on the ideXlab platform.
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Increased testicular blood flow maintains oxygen delivery and avoids testicular hypoxia in response to reduced oxygen content in Inspired Air.
Scientific Reports, 2018Co-Authors: G. Rizzoto, C. Hall, J. V. Tyberg, Jacob C. Thundathil, N. A. Caulkett, John P. KastelicAbstract:Despite a long-standing assertion that mammalian testes operate near hypoxia and increased testicular temperature causes frank hypoxia, we have preliminary evidence that changes are due to hyperthermia per se. The objective was to determine how variations in Inspired oxygen concentration affected testicular blood flow, oxygen delivery and extraction, testicular temperature and lactate production. Eight rams were maintained under general anesthesia, with successive decreases in oxygen concentration in Inspired Air (100, 21 and 13%, respectively). As oxygen concentration decreased from 100 to 13%, there were increases in testicular blood flow (9.6 ± 1.7 vs 12.9 ± 1.9 ml/min/100 g of testis, P
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increased testicular blood flow maintains oxygen delivery and avoids testicular hypoxia in response to reduced oxygen content in Inspired Air
Scientific Reports, 2018Co-Authors: G. Rizzoto, C. Hall, J. V. Tyberg, Jacob C. Thundathil, N. A. Caulkett, John P. KastelicAbstract:Despite a long-standing assertion that mammalian testes operate near hypoxia and increased testicular temperature causes frank hypoxia, we have preliminary evidence that changes are due to hyperthermia per se. The objective was to determine how variations in Inspired oxygen concentration affected testicular blood flow, oxygen delivery and extraction, testicular temperature and lactate production. Eight rams were maintained under general anesthesia, with successive decreases in oxygen concentration in Inspired Air (100, 21 and 13%, respectively). As oxygen concentration decreased from 100 to 13%, there were increases in testicular blood flow (9.6 ± 1.7 vs 12.9 ± 1.9 ml/min/100 g of testis, P < 0.05; mean ± SEM) and conductance (normalized flow; 0.46 ± 0.07 to 1.28 ± 0.19 ml/min/mm Hg/100 g testis (P < 0.05). Increased testicular blood flow maintained oxygen delivery and increased testicular temperature by ~1 °C; this increase was correlated to increased testicular blood flow (r = 0.35, P < 0.0001). Furthermore, oxygen utilization increased concomitantly and there were no significant differences among oxygen concentrations in blood pH, HCO3− or base excess, and no effects of venous-arterial differences in lactate production. In conclusion, under acute hypoxic conditions, testes maintained oxygen delivery and uptake by increasing blood flow and oxygen extraction, with no evidence of anaerobic metabolism. However, additional studies are needed to determine longer-term responses and potential evidence of anaerobic metabolism at the molecular level.
G. Rizzoto - One of the best experts on this subject based on the ideXlab platform.
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Increased testicular blood flow maintains oxygen delivery and avoids testicular hypoxia in response to reduced oxygen content in Inspired Air.
Scientific Reports, 2018Co-Authors: G. Rizzoto, C. Hall, J. V. Tyberg, Jacob C. Thundathil, N. A. Caulkett, John P. KastelicAbstract:Despite a long-standing assertion that mammalian testes operate near hypoxia and increased testicular temperature causes frank hypoxia, we have preliminary evidence that changes are due to hyperthermia per se. The objective was to determine how variations in Inspired oxygen concentration affected testicular blood flow, oxygen delivery and extraction, testicular temperature and lactate production. Eight rams were maintained under general anesthesia, with successive decreases in oxygen concentration in Inspired Air (100, 21 and 13%, respectively). As oxygen concentration decreased from 100 to 13%, there were increases in testicular blood flow (9.6 ± 1.7 vs 12.9 ± 1.9 ml/min/100 g of testis, P
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increased testicular blood flow maintains oxygen delivery and avoids testicular hypoxia in response to reduced oxygen content in Inspired Air
Scientific Reports, 2018Co-Authors: G. Rizzoto, C. Hall, J. V. Tyberg, Jacob C. Thundathil, N. A. Caulkett, John P. KastelicAbstract:Despite a long-standing assertion that mammalian testes operate near hypoxia and increased testicular temperature causes frank hypoxia, we have preliminary evidence that changes are due to hyperthermia per se. The objective was to determine how variations in Inspired oxygen concentration affected testicular blood flow, oxygen delivery and extraction, testicular temperature and lactate production. Eight rams were maintained under general anesthesia, with successive decreases in oxygen concentration in Inspired Air (100, 21 and 13%, respectively). As oxygen concentration decreased from 100 to 13%, there were increases in testicular blood flow (9.6 ± 1.7 vs 12.9 ± 1.9 ml/min/100 g of testis, P < 0.05; mean ± SEM) and conductance (normalized flow; 0.46 ± 0.07 to 1.28 ± 0.19 ml/min/mm Hg/100 g testis (P < 0.05). Increased testicular blood flow maintained oxygen delivery and increased testicular temperature by ~1 °C; this increase was correlated to increased testicular blood flow (r = 0.35, P < 0.0001). Furthermore, oxygen utilization increased concomitantly and there were no significant differences among oxygen concentrations in blood pH, HCO3− or base excess, and no effects of venous-arterial differences in lactate production. In conclusion, under acute hypoxic conditions, testes maintained oxygen delivery and uptake by increasing blood flow and oxygen extraction, with no evidence of anaerobic metabolism. However, additional studies are needed to determine longer-term responses and potential evidence of anaerobic metabolism at the molecular level.
Sandra D Anderson - One of the best experts on this subject based on the ideXlab platform.
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a reinterpretation of the effect of temperature and water content of the Inspired Air in exercise induced asthma
The American review of respiratory disease, 2015Co-Authors: A G Hahn, Sandra D Anderson, A R Morton, Judith L Black, Kenneth D FitchAbstract:To compare the importance of water loss with heat loss in the mechanism of exercise-induced asthma (EIA), we conditioned the Air Inspired during exercise to the same water content (Wi) while changing its temperature (Ti), and vice versa. We calculated separately the amount of heat and water required to bring the Inspired Air to alveolar conditions. Ten asthmatics ran for 8 min on 4 occasions in an environmental chamber. The Air was conditioned to a Ti of 9 to 10° C or 35° C, with a Wi of 9 to 10 mg H2OL−1 The Airway response to exercise was not significantly different when Ti varied by 25° C, but the amount of water required to saturate the Inspired Air remained the same. However, the amount of heat required was significantly greater with cooler Air (p < 0.005). We conclude that it is the osmotic and not the cooling effects induced by the vaporizaton of water that is the more important factor determining EIA.
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Reproducibility of the Airway response to an exercise protocol standardized for intensity, duration, and Inspired Air conditions, in subjects with symptoms suggestive of asthma
Respiratory Research, 2010Co-Authors: Sandra D Anderson, David S. Pearlman, Kenneth W. Rundell, Claire P Perry, Homer A. Boushey, Christine A. Sorkness, Sara Nichols, John M. WeilerAbstract:Exercise testing to aid diagnosis of exercise-induced bronchoconstriction (EIB) is commonly performed. Reproducibility of the Airway response to a standardized exercise protocol has not been reported in subjects being evaluated with mild symptoms suggestive of asthma but without a definite diagnosis. This study examined reproducibility of % fall in FEV1 and area under the FEV1 time curve for 30 minutes in response to two exercise tests performed with the same intensity and duration of exercise, and Inspired Air conditions. Subjects with mild symptoms of asthma exercised twice within approximately 4 days by running for 8 minutes on a motorized treadmill breathing dry Air at an intensity to induce a heart rate between 80-90% predicted maximum; reproducibility of the Airway response was expressed as the 95% probability interval. Of 373 subjects challenged twice 161 were positive (≥10% fall FEV1 on at least one challenge). The EIB was mild and 77% of subjects had
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reproducibility of the Airway response to an exercise protocol standardized for intensity duration and Inspired Air conditions in subjects with symptoms suggestive of asthma
Respiratory Research, 2010Co-Authors: Sandra D Anderson, David S. Pearlman, Kenneth W. Rundell, Claire P Perry, Homer A. Boushey, Christine A. Sorkness, Sara Nichols, John M. WeilerAbstract:Exercise testing to aid diagnosis of exercise-induced bronchoconstriction (EIB) is commonly performed. Reproducibility of the Airway response to a standardized exercise protocol has not been reported in subjects being evaluated with mild symptoms suggestive of asthma but without a definite diagnosis. This study examined reproducibility of % fall in FEV1 and area under the FEV1 time curve for 30 minutes in response to two exercise tests performed with the same intensity and duration of exercise, and Inspired Air conditions. Subjects with mild symptoms of asthma exercised twice within approximately 4 days by running for 8 minutes on a motorized treadmill breathing dry Air at an intensity to induce a heart rate between 80-90% predicted maximum; reproducibility of the Airway response was expressed as the 95% probability interval. Of 373 subjects challenged twice 161 were positive (≥10% fall FEV1 on at least one challenge). The EIB was mild and 77% of subjects had <15% fall on both challenges. Agreement between results was 76.1% with 56.8% (212) negative (< 10% fall FEV1) and 19.3% (72) positive on both challenges. The remaining 23.9% of subjects had only one positive test. The 95% probability interval for reproducibility of the % fall in FEV1 and AUC0-30 min was ± 9.7% and ± 251% for all 278 adults and ± 13.4% and ± 279% for all 95 children. The 95% probability interval for reproducibility of % fall in FEV1 and AUC0-30 min for the 72 subjects with two tests ≥10% fall FEV1 was ± 14.6% and ± 373% and for the 34 subjects with two tests ≥15% fall FEV1 it was ± 12.2% and ± 411%. Heart rate and estimated ventilation achieved were not significantly different either on the two test days or when one test result was positive and one was negative. Under standardized, well controlled conditions for exercise challenge, the majority of subjects with mild symptoms of asthma demonstrated agreement in test results. Performing two tests may need to be considered when using exercise to exclude or diagnose EIB, when prescribing prophylactic treatment to prevent EIB and when designing protocols for clinical trials.
Jacob C. Thundathil - One of the best experts on this subject based on the ideXlab platform.
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Increased testicular blood flow maintains oxygen delivery and avoids testicular hypoxia in response to reduced oxygen content in Inspired Air.
Scientific Reports, 2018Co-Authors: G. Rizzoto, C. Hall, J. V. Tyberg, Jacob C. Thundathil, N. A. Caulkett, John P. KastelicAbstract:Despite a long-standing assertion that mammalian testes operate near hypoxia and increased testicular temperature causes frank hypoxia, we have preliminary evidence that changes are due to hyperthermia per se. The objective was to determine how variations in Inspired oxygen concentration affected testicular blood flow, oxygen delivery and extraction, testicular temperature and lactate production. Eight rams were maintained under general anesthesia, with successive decreases in oxygen concentration in Inspired Air (100, 21 and 13%, respectively). As oxygen concentration decreased from 100 to 13%, there were increases in testicular blood flow (9.6 ± 1.7 vs 12.9 ± 1.9 ml/min/100 g of testis, P
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increased testicular blood flow maintains oxygen delivery and avoids testicular hypoxia in response to reduced oxygen content in Inspired Air
Scientific Reports, 2018Co-Authors: G. Rizzoto, C. Hall, J. V. Tyberg, Jacob C. Thundathil, N. A. Caulkett, John P. KastelicAbstract:Despite a long-standing assertion that mammalian testes operate near hypoxia and increased testicular temperature causes frank hypoxia, we have preliminary evidence that changes are due to hyperthermia per se. The objective was to determine how variations in Inspired oxygen concentration affected testicular blood flow, oxygen delivery and extraction, testicular temperature and lactate production. Eight rams were maintained under general anesthesia, with successive decreases in oxygen concentration in Inspired Air (100, 21 and 13%, respectively). As oxygen concentration decreased from 100 to 13%, there were increases in testicular blood flow (9.6 ± 1.7 vs 12.9 ± 1.9 ml/min/100 g of testis, P < 0.05; mean ± SEM) and conductance (normalized flow; 0.46 ± 0.07 to 1.28 ± 0.19 ml/min/mm Hg/100 g testis (P < 0.05). Increased testicular blood flow maintained oxygen delivery and increased testicular temperature by ~1 °C; this increase was correlated to increased testicular blood flow (r = 0.35, P < 0.0001). Furthermore, oxygen utilization increased concomitantly and there were no significant differences among oxygen concentrations in blood pH, HCO3− or base excess, and no effects of venous-arterial differences in lactate production. In conclusion, under acute hypoxic conditions, testes maintained oxygen delivery and uptake by increasing blood flow and oxygen extraction, with no evidence of anaerobic metabolism. However, additional studies are needed to determine longer-term responses and potential evidence of anaerobic metabolism at the molecular level.
J. V. Tyberg - One of the best experts on this subject based on the ideXlab platform.
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Increased testicular blood flow maintains oxygen delivery and avoids testicular hypoxia in response to reduced oxygen content in Inspired Air.
Scientific Reports, 2018Co-Authors: G. Rizzoto, C. Hall, J. V. Tyberg, Jacob C. Thundathil, N. A. Caulkett, John P. KastelicAbstract:Despite a long-standing assertion that mammalian testes operate near hypoxia and increased testicular temperature causes frank hypoxia, we have preliminary evidence that changes are due to hyperthermia per se. The objective was to determine how variations in Inspired oxygen concentration affected testicular blood flow, oxygen delivery and extraction, testicular temperature and lactate production. Eight rams were maintained under general anesthesia, with successive decreases in oxygen concentration in Inspired Air (100, 21 and 13%, respectively). As oxygen concentration decreased from 100 to 13%, there were increases in testicular blood flow (9.6 ± 1.7 vs 12.9 ± 1.9 ml/min/100 g of testis, P
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increased testicular blood flow maintains oxygen delivery and avoids testicular hypoxia in response to reduced oxygen content in Inspired Air
Scientific Reports, 2018Co-Authors: G. Rizzoto, C. Hall, J. V. Tyberg, Jacob C. Thundathil, N. A. Caulkett, John P. KastelicAbstract:Despite a long-standing assertion that mammalian testes operate near hypoxia and increased testicular temperature causes frank hypoxia, we have preliminary evidence that changes are due to hyperthermia per se. The objective was to determine how variations in Inspired oxygen concentration affected testicular blood flow, oxygen delivery and extraction, testicular temperature and lactate production. Eight rams were maintained under general anesthesia, with successive decreases in oxygen concentration in Inspired Air (100, 21 and 13%, respectively). As oxygen concentration decreased from 100 to 13%, there were increases in testicular blood flow (9.6 ± 1.7 vs 12.9 ± 1.9 ml/min/100 g of testis, P < 0.05; mean ± SEM) and conductance (normalized flow; 0.46 ± 0.07 to 1.28 ± 0.19 ml/min/mm Hg/100 g testis (P < 0.05). Increased testicular blood flow maintained oxygen delivery and increased testicular temperature by ~1 °C; this increase was correlated to increased testicular blood flow (r = 0.35, P < 0.0001). Furthermore, oxygen utilization increased concomitantly and there were no significant differences among oxygen concentrations in blood pH, HCO3− or base excess, and no effects of venous-arterial differences in lactate production. In conclusion, under acute hypoxic conditions, testes maintained oxygen delivery and uptake by increasing blood flow and oxygen extraction, with no evidence of anaerobic metabolism. However, additional studies are needed to determine longer-term responses and potential evidence of anaerobic metabolism at the molecular level.