Carbon dioxide (CO) and oxygen (O) influence the breathing pattern of reptiles, especially when CO is in excess or O at low concentrations and the effects of these gases on the respiratory response varies according to the species. In addition to respiratory gases, seasonal changes can also modulate breathing pattern and ventilatory responses to hypoxia and hypercarbia. Therefore, the present study investigated the breathing pattern and ventilatory responses to hypercarbia (5% CO) and hypoxia (5% O) of the Neotropical lizard Tropidurus torquatus over a period of one year, covering all seasons (summer, autumn, winter and spring). Our data suggest that like other ectothermic sauropsids, Tropidurus torquatus possesses distinct ventilatory responses to hypoxia and hypercarbia, being more sensitive to changes in CO than in O. Additionally, the ventilatory responses to hypoxia were more pronounced during summer and hypercanic and pos-hypercapnic ventilatory response was reduced during spring, suggesting that seasonality modulates the control of ventilation in this species.
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http://dx.doi.org/10.1016/j.cbpa.2019.110534 | DOI Listing |
Int J Chron Obstruct Pulmon Dis
January 2025
Division of Pulmonary Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei City, Taiwan, Republic of China.
Background: Chronic obstructive pulmonary disease (COPD) is characterized by airway inflammation, airflow limitation, reduced health-related quality of life (HRQL), and exercise intolerance. Pulmonary rehabilitation (PR) is essential for COPD management, but outcomes may be influenced by individual physiological factors. Cardiopulmonary exercise testing (CPET) measures oxygen pulse (O2P), an indicator of stroke volume, yet the impact of baseline O2P on PR effectiveness remains unclear.
View Article and Find Full Text PDFHeart
December 2024
Centro Cardiologico Monzino, IRCCS, Milan, Italy.
Background: Little evidence is available about heart rate (HR) response to exercise as well as its relationship with functional capacity in amyloid cardiomyopathy. Then, in a multicentre cohort of patients with amyloid cardiomyopathy, we investigated the prevalence of chronotropic incompetence (CI) and its relationships with cardiopulmonary exercise testing (CPET) variables.
Methods: Data from 172 outpatients with amyloid cardiomyopathy who performed a maximal CPET and who had no significant rhythm disorders were analysed.
Crit Care
January 2025
Departamento de Medicina, Hospital Clínico Universidad de Chile, Unidad de Pacientes Críticos, Dr. Carlos Lorca Tobar 999, Independencia, Santiago, Chile.
Background: Double cycling with breath-stacking (DC/BS) during controlled mechanical ventilation is considered potentially injurious, reflecting a high respiratory drive. During partial ventilatory support, its occurrence might be attributable to physiological variability of breathing patterns, reflecting the response of the mode without carrying specific risks.
Methods: This secondary analysis of a crossover study evaluated DC/BS events in hypoxemic patients resuming spontaneous breathing in cross-over under neurally adjusted ventilatory assist (NAVA), proportional assist ventilation (PAV +), and pressure support ventilation (PSV).
Proc Natl Acad Sci U S A
January 2025
Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, AB T3E 6K6, Canada.
With over 14 million people living above 3,500 m, the study of acclimatization and adaptation to high altitude in human populations is of increasing importance, where exposure to high altitude (HA) imposes a blood oxygenation and acid-base challenge. A sustained and augmented hypoxic ventilatory response protects oxygenation through ventilatory acclimatization, but elicits hypocapnia and respiratory alkalosis. A subsequent renally mediated compensatory metabolic acidosis corrects pH toward baseline values, with a high degree of interindividual variability.
View Article and Find Full Text PDFAm J Physiol Lung Cell Mol Physiol
January 2025
Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile.
Chronic intermittent hypoxia (CIH), the main feature of obstructive sleep apnea, heightened chemosensory discharges of the carotid body (CB), which contributes to potentiate the ventilatory hypoxic response and elicits hypertension. We aimed to determine: 1) whether the persistence of cardiorespiratory alterations found in long-term CIH depend on the inputs from the CB and, 2) in what extension the activation of glial cells and neuroinflammation in the caudal region of the nucleus of the Solitary Tract (NTS) requires functional CB chemosensory activity. To evaluate these hypotheses, we exposed male mice to CIH for 60 days.
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