Experimental Physiology最新文献

{"title":"Comments on Rajizadeh et al. (2023) 'Comparison of preventive and therapeutic effects of continuous exercise on acute lung injury induced with methotrexate'.","authors":"Mehran Hosseini","doi":"10.1113/EP092385","DOIUrl":"https://doi.org/10.1113/EP092385","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143002712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nocturnal pulse oxygen saturation dynamics at simulated high altitude: Predictive value for acute mountain sickness in healthy men born pre-term.","authors":"Benjamin J Narang, Giorgio Manferdelli, Grégoire P Millet, Tadej Debevec","doi":"10.1113/EP092418","DOIUrl":"https://doi.org/10.1113/EP092418","url":null,"abstract":"<p><p>The physiological sequelae of pre-term birth might influence the responses of this population to hypoxia. Moreover, identifying variables associated with development of acute mountain sickness (AMS) remains a key practically significant area of altitude research. We investigated the effects of pre-term birth on nocturnal oxygen saturation ( <math> <semantics><msub><mi>S</mi> <mrow><mi>p</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${{S}_{{mathrm{p}}{{{mathrm{O}}}_{mathrm{2}}}}}$</annotation></semantics> </math> ) dynamics and assessed the predictive potential of nocturnal <math> <semantics><msub><mi>S</mi> <mrow><mi>p</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${{S}_{{mathrm{p}}{{{mathrm{O}}}_{mathrm{2}}}}}$</annotation></semantics> </math> -related metrics for morning AMS in 12 healthy adults with gestational age < 32 weeks (pre-term) and 12 term-born control participants. Participants spent one night at a simulated altitude of ∼4200 m (normobaric hypoxia; fraction of inspired O<sub>2 </sub>= 0.141), with nocturnal <math> <semantics><msub><mi>S</mi> <mrow><mi>p</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${{S}_{{mathrm{p}}{{{mathrm{O}}}_{mathrm{2}}}}}$</annotation></semantics> </math> and heart rate recorded continuously at the fingertip using pulse oximetry and with morning AMS assessed using the Lake Louise scale. Pre-term and term-born participants had similar nocturnal mean <math> <semantics><msub><mi>S</mi> <mrow><mi>p</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${{S}_{{mathrm{p}}{{{mathrm{O}}}_{mathrm{2}}}}}$</annotation></semantics> </math> (mean ± SD; 77% ± 3% vs. 77% ± 4%; P = 0.661), minimum <math> <semantics><msub><mi>S</mi> <mrow><mi>p</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${{S}_{{mathrm{p}}{{{mathrm{O}}}_{mathrm{2}}}}}$</annotation></semantics> </math> (median[IQR]; 67[4]% vs. 69[5]%; P = 0.223), relative time spent with <math> <semantics><msub><mi>S</mi> <mrow><mi>p</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${{S}_{{mathrm{p}}{{{mathrm{O}}}_{mathrm{2}}}}}$</annotation></semantics> </math> <sub> </sub>< 80% (72% ± 29% vs. 70% ± 27%; P = 0.879) and mean heart rate (79 ± 12 vs. 71 ± 7 beats/min; P = 0.053). However, the increase in <math> <semantics><msub><mi>S</mi> <mrow><mi>p</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${{S}_{{mathrm{p}}{{{mathrm{O}}}_{mathrm{2}}}}}$</annotation></semantics> </math> between the two halves of the night was blunted with prematurity (-0.12% ± 1.51% vs. 1.11% ± 0.78%; P = 0.021). Moreover, the cumulative relative desaturation-based hypoxic 'load' was higher with prematurity (32[26]%min/h vs. 7[25]%min/h; P = 0.039), underpinned by increased desaturation frequency (69[49] vs. 21[35] counts/h; P = 0.009). Mean <math> <semantics><msub><mi>S</mi> <mrow><mi>p</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${{S","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143002766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dual test gas pulmonary diffusing capacity in patients with idiopathic scoliosis 40 years after diagnosis.","authors":"Rie S Thomsen, Milan Mohammad, Lærke C Ragborg, Casper Dragsted, Søren Ohrt-Nissen, Martin Gehrchen, Benny Dahl, Ronan M G Berg, Jann Mortensen","doi":"10.1113/EP092251","DOIUrl":"https://doi.org/10.1113/EP092251","url":null,"abstract":"<p><p>There is limited knowledge on diffusing capacity in scoliosis patients. It remains to be determined if impaired pulmonary diffusing capacity is mostly influenced by reduced alveolar-capillary membrane diffusing capacity (D_{M, CO}), reduced pulmonary capillary blood volume (V_C) or both. This study aims to report findings from dual test gas pulmonary diffusing capacity for carbon monoxide and nitric oxide (D_{L, CO, NO}) with quantification of pulmonary diffusing capacity for carbon monoxide corrected for haemoglobin with a five s breath-hold (D_{L, COc, 5s}) and nitric oxide with a five s breath-hold (D_{L, NO, 5s}), D_{M, CO} and V_C. The study included 57 patients with idiopathic scoliosis seen at our department from 1972 to 1983, all of whom underwent radiological assessment and measurement of D_{L, CO, NO} during examination 40 years after diagnosis. One-way ANOVA was performed for between-group differences and Pearson's correlation coefficient was used to assess correlations between D_{L, CO, NO} metrics and Cobb angle. No significant between-group differences based on disease severity were detected. Thirty-nine percent of the patients were presented with either reduced D_{L, COc, 5s} or reduced D_{L, NO, 5s} represented as Z-scores below -1.65. No significant correlations between Cobb angle and Z-scores for D_{L, COc, 5s}, D_{L, NO, 5s}, D_{M, CO} and V_C according to height measurements were found. When using arm span instead, a weak negative correlation between D_{L, COc, 5s} and Cobb angle (r = -0.29; P = 0.04) was detected. In conclusion, approximately 39% of patients with idiopathic scoliosis had either reduced D_{L, COc, 5s} or reduced D_{L, NO, 5s} 40 years after diagnosis with varying contributions from V_C or D_{M, CO}.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143002763","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Astrocyte proliferation in the hippocampal dentate gyrus is suppressed across the lifespan of dystrophin-deficient mdx mice.","authors":"Kimberley A Stephenson, Polly Peters, Mark G Rae, Dervla O'Malley","doi":"10.1113/EP092150","DOIUrl":"https://doi.org/10.1113/EP092150","url":null,"abstract":"<p><p>Absence of the structural protein, dystrophin, results in the neuromuscular disorder Duchenne Muscular Dystrophy (DMD). In addition to progressive skeletal muscle dysfunction, this multisystemic disorder can also result in cognitive deficits and behavioural changes that are likely to be consequences of dystrophin loss from central neurons and astrocytes. Dystrophin-deficient mdx mice exhibit decreases in grey matter volume in the hippocampus, the brain region that encodes and consolidates memories, and this is exacerbated with ageing. To understand changes in cellular composition that might underpin these age-related developments, we have compared neurogenesis and the prevalence of immunofluorescently identified newly born and mature neurons, astrocytes and microglia in the dentate gyrus of mdx and wild-type mice at 2, 4, 8 and 16 months of age. The number of adult-born neurons was suppressed in the dentate gyrus subgranular zone of 2-month-old mdx mice. However, the numbers of granule cells and GABA_A receptor, alpha 1-expressing cells were similar in wild-type and mdx mice at all ages. Strikingly, the numbers of astrocytes, particularly in the dentate gyrus molecular layer, were suppressed in mdx mice at all time points. Thus, dystrophin loss was associated with reduced hippocampal neurogenesis in early life but did not impact the prevalence of mature neurons across the lifespan of mdx mice. In contrast, normal age-related dentate gyrus astrocyte proliferation was suppressed in dystrophic mice. Astrocytes are the most abundant cell type in the brain and are crucial in supporting neuronal function, such that loss of these cells is likely to contribute to hippocampal dysfunction reported in mdx mice.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142962145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting high-performance decathlon career best.","authors":"Perry Battles, Tyler J Noble, Robert F Chapman","doi":"10.1113/EP091921","DOIUrl":"https://doi.org/10.1113/EP091921","url":null,"abstract":"<p><p>The decathlon is a 10-event discipline in the sport of track and field, typically offered only for men at the elite level of competition (heptathlon is the complementary event for women). It is composed of 10 distinct events contested over 2 days. Using event-specific coefficients, marks are converted to scores, which sum to produce an overall score. Ten events that share some underlying features, but also some disparate features, create a challenge for coaches and sports administrators in identifying potential elite talent and developing it optimally across the career. In this investigation, decathletes were profiled on the basis of keeping performances ≥6400 points and including only those participants who competed in ≥4 years <math> <semantics><mrow><mo>(</mo> <mrow><mi>n</mi> <mo>=</mo> <mn>642</mn></mrow> <mo>)</mo></mrow> <annotation>$( {n = 642} )$</annotation></semantics> </math> . Using gamma generalized linear regression models, the first-season best mark and improvement in each event were related to all-time career best. Coefficients were compared to infer priorities for elite decathlete selection (using first-season best marks in each event) and development (using the delta or improvement in each event). These data show that the most crucial event for identifying an athlete with a future potential elite all-time career best is the pole vault, followed by the javelin throw, long jump and shot put. For optimal career development, the data suggest athletes obtain the most return by focusing on improvement in the pole vault and long jump.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142946938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrasonographic evaluation of diaphragm fatigue in healthy humans.","authors":"Camilla R Illidi, Lee M Romer","doi":"10.1113/EP092322","DOIUrl":"https://doi.org/10.1113/EP092322","url":null,"abstract":"<p><p>Assessment of diaphragm function and fatigue typically relies on the measurement of transdiaphragmatic pressure (P_di). Although P_di serves as an index of diaphragm force output, it provides limited information regarding the ability of the muscle to shorten and generate power. We asked whether ultrasonography, combined with P_di, could be used to quantify changes in diaphragm function attributable to fatigue. Eight healthy men [mean (SD) age, 23 (7) years] completed two tasks on separate occasions: (i) 2 min of maximal isocapnic ventilation (MIV); or (ii) 3 × 5 min of maximal inspiratory resistive loading (IRL). Diaphragm function was evaluated before (PRE) and after each task (POST₁, 10-15 min and POST₂, 30-35 min) using synchronous recordings of P_di and subcostal ultrasound traces of the right crural hemidiaphragm during anterolateral magnetic stimulation of the phrenic nerves and progressive CO₂ rebreathing. Fatigue was quantified as pre- to post-loading changes in twitch P_di, excursion velocity (excursion/time) and power (P_di × velocity). Both tasks resulted in significant reductions in twitch P_di (P < 0.05). There were no effects of MIV on ultrasound-derived measures. In contrast, IRL elicited a significant reduction in twitch excursion at POST₁ (-16%; P = 0.034) and significant reductions in excursion velocity at POST₁ (-32%; P = 0.022) and POST₂ (-28%; P = 0.013). These reductions in excursion velocity, alongside the concurrent reductions in twitch P_di, resulted in significant reductions in diaphragm power at POST₁ (-48%; P = 0.009) and POST₂ (-42%; P = 0.008). Neither task significantly altered the contractile responses to CO₂. In conclusion, subcostal ultrasonography coupled with phrenic nerve stimulation is a promising method for quantifying contractile fatigue of the human diaphragm.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142946985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Confined spaces in space: Cerebral implications of chronic elevations of inspired carbon dioxide and implications for long-duration space travel.","authors":"Jay M J R Carr, Philip N Ainslie, Trevor Day","doi":"10.1113/EP091659","DOIUrl":"https://doi.org/10.1113/EP091659","url":null,"abstract":"<p><p>Cerebrovascular regulation is critically dependent upon the arterial partial pressure of carbon dioxide ( <math> <semantics><msub><mi>P</mi> <mrow><mi>aC</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${P_{{mathrm{aC}}{{mathrm{O}}_{mathrm{2}}}}}$</annotation></semantics> </math> ), owing to its effect on cerebral blood flow, tissue <math> <semantics><msub><mi>P</mi> <mrow><mi>C</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${P_{{mathrm{C}}{{mathrm{O}}_{mathrm{2}}}}}$</annotation></semantics> </math> , tissue proton concentration, cerebral metabolism and cognitive and neuronal function. In normal environments and in the absence of pathology, at least over acute time frames, hypercapnia is usually managed readily via the respiratory chemoreflex arcs and/or acid-base buffering capacity, such that there is minimal impact on cerebrovascular and neurological function. However, in non-normal environments, such as enclosed spaces, or with pathology, extended exposures to elevations in <math> <semantics><msub><mi>P</mi> <mrow><mi>aC</mi> <msub><mi>O</mi> <mn>2</mn></msub> </mrow> </msub> <annotation>${P_{{mathrm{aC}}{{mathrm{O}}_{mathrm{2}}}}}$</annotation></semantics> </math> can be detrimental to cerebral health. Given the direct effect of protons on cellular function, even if pH is normalized, it is feasible that higher proton concentrations could still produce detrimental effects. Although it seems that humans can work safely in mildly hypercapnic environments for extended periods, chronic respiratory acidosis can cause bone demineralization, renal calcification, perinatal developmental abnormalities, systemic inflammation and impairments in cognitive function and visuomotor skills and can produce cerebral acidosis, potentially inducing sustained alterations in cerebral function. With the advancement of new initiatives in spaceflight, including proposed long-duration missions to Mars, the study of the effects of chronic inspired CO₂ on human health is relevant. In this review, we draw on evidence from preclinical, physiological and clinical research in humans to summarize the cerebral ramifications of prolonged and chronic exposures to elevated partial pressures of inspired CO₂ and respiratory acidosis.</p>","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142946921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Is the blood pressure response to exercise associated with the motor unit firing patterns of the exercised muscle?","authors":"Shigehiko Ogoh","doi":"10.1113/EP092462","DOIUrl":"10.1113/EP092462","url":null,"abstract":"&lt;p&gt;Arterial blood pressure (ABP) increases during exercise to support the elevated muscle metabolism required for physical activity. This response is particularly pronounced in elderly individuals, those with cardiovascular diseases such as hypertension, and even some healthy individuals (Kunimatsu et al., &lt;span&gt;2024&lt;/span&gt;). Notably, such an exaggerated ABP response during exercise is associated with an increased risk of damage to cerebral and cardiac vasculature, especially in these populations. Despite these concerns, the mechanisms underlying individual differences in ABP responses to exercise remain poorly understood. ABP during exercise is influenced by the force generated during physical activity, which is regulated by the neuromuscular system. This regulation involves factors such as motor unit firing rates, motor unit recruitment thresholds and the interplay between these elements. Additionally, these factors play a crucial role in determining the efficiency of microvascular unit perfusion during exercise. These findings suggest that the motor unit firing pattern may be a key determinant of ABP response to exercise. Given this background, in this issue of &lt;i&gt;Experimental Physiology&lt;/i&gt;, Takeda et al. (&lt;span&gt;2025&lt;/span&gt;) report differences in the motor unit firing patterns during exercise between normotensive, treated hypertensive and untreated hypertensive individuals. They also examined the effects of these differences in motor unit firing patterns on post-exercise ABP responses.&lt;/p&gt;&lt;p&gt;The authors found that in treated hypertensive and normotensive individuals, firing rates of larger motor units were lower than those of smaller motor units, while in untreated hypertensive individuals, firing rates of larger motor units were similar to those of smaller ones. This suggests that motor unit firing patterns differ across cardiovascular conditions. Additionally, they reported that the firing rates and slope of larger motor units were positively correlated with changes in systolic blood pressure (SBP) from rest to post-exercise in hypertensive individuals. This implies a link between exercise-induced motor unit firing patterns and cardiovascular response. However, post-exercise ABP responses did not directly reflect the ABP response during exercise, making it challenging to determine the effect of motor unit firing patterns on ABP in this study. Also, the negative change in SBP in hypertensive individuals from baseline to post-exercise may involve several physiological factors and should not be directly tied to exercise-induced ABP changes. Nevertheless, it is essential to confirm whether their hypothesis holds true within the context of this study.&lt;/p&gt;&lt;p&gt;Fortunately, previous studies (Currie et al., &lt;span&gt;2025&lt;/span&gt;; Lacy et al., &lt;span&gt;2015&lt;/span&gt;) have reported ABP responses to exercise in hypertensive individuals, allowing speculation on how motor unit firing patterns may influence ABP responses. It is well-established that hypertensive pa","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":"110 2","pages":"189-190"},"PeriodicalIF":2.6,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11782178/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142926938","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"News, views and where best to choose.","authors":"Ken D O'Halloran","doi":"10.1113/EP092477","DOIUrl":"https://doi.org/10.1113/EP092477","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142913582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Does hydration status affect ventilation during prolonged exercise?","authors":"Naoto Fujii","doi":"10.1113/EP092332","DOIUrl":"https://doi.org/10.1113/EP092332","url":null,"abstract":"","PeriodicalId":12092,"journal":{"name":"Experimental Physiology","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142913577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}