Publications by authors named "P N Ainslie"
Cerebrovascular regulation is critically dependent upon the arterial partial pressure of carbon dioxide ( ), owing to its effect on cerebral blood flow, tissue , 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 can be detrimental to cerebral health.
View Article and Find Full Text PDFThe brain is highly innervated by sympathetic nerve fibres; however, their physiological purpose is poorly understood. We hypothesized that unilateral cerebral norepinephrine (NE) spillover, an index of cerebral sympathetic nerve activity (SNA), would be elevated when engaging the baroreflex [via lower-body negative pressure (LBNP; -20 and -40 Torr)] and respiratory chemoreflexes [via carbon dioxide (CO) administration (+8 Torr)], independently, and in combination. Twelve young and healthy participants (5 females) underwent simultaneous blood sampling from the right radial artery and internal jugular vein.
View Article and Find Full Text PDFBackground: Respiratory dysfunction is an important contributor to morbidity and mortality in advanced Parkinson's disease (PD), but it is unclear what parameters are sensitive to diagnose and monitor respiratory dysfunction across disease phases.
Objectives: We aimed to characterize respiratory dysfunction in mild to moderate PD.
Methods: In 20 individuals without cardiopulmonary comorbidity, pulmonary and inspiratory muscle function testing were performed ON-medication.
Article Synopsis
- Doubly labeled water is the most reliable method for measuring total energy expenditure (TEE), but its accuracy can be affected by the isotope dilution space ratio (DSR).
- This study explored factors like age, sex, ethnicity, body composition, and geographical elevation to see how they influence DSR, using various statistical analysis methods.
- Results showed that while DSR decreased with age in individuals 60 and older, no significant effects were found from other variables, suggesting that previous estimates of TEE might be overestimating values for older individuals, especially those around 90 years old.
Background: Since vascular responses to hypoxia in both healthy high-altitude natives and chronic mountain sickness (a maladaptive high-altitude pathology characterised by excessive erythrocytosis and the presence of symptoms-CMS) remain unclear, the role of inflammation and oxidative/nitrosative stress on the endothelium- and - responses in both the micro- and macrocirculation, in healthy Andeans at different altitudes and in CMS patients, was examined.
Methods: 94 men were included: 18 lowlanders (LL), 38 healthy highlanders permanently living at 3800 m (n = 21-HL-3800) or in La Rinconada, the highest city in the world (5100-5300 m) (n = 17-HL-5100/No CMS). Moreover, 14 participants with mild (Mild CMS) and 24 with moderate to severe CMS (Mod/Sev CMS) were recruited.