Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 35 for “"hypercapnia"”.
-
Hypothalamic and medullary modulation of cardiorespiratory responses to hypoxia and hypercapnia
… in the cardiorespiratory response to hypoxia and hypercapnia was examined. Initial experiments performed on anesthetized rats demonstrated that microinjection into the rostral ventrolateral medulla (VLM) of the excitatory amino acid receptor antagonist kynurenic acid resulted in increased …
-
Sub-Lethal Effects of Hypoxia/Hypercapnia on Callinectes Sapidus in the York River Estuary, Virginia
… oxygen (D.O.), increased carbon dioxide (hypercapnia), and low pH concurrently. The objectives were to: 1) identify hypoxiahypercapnia by monitoring D.O. and pH as an indicator of hypercapnia in shallow regions of the York River, 2) measure blue crab abundance, and 3) describe blue crab …
-
Activation of 5-HT1A Receptors in the Nucleus Tractus Solitarius Facilitate Ventilatory Responses to Hypoxic Hypercapnia and Promote Sympathetic Recovery Following Hypotensive Hemorrhage
… hemorrhage and ventilatory responses to hypoxic/hypercapnia. Sequences encoding a 5-HT<sub>1A</sub> shRNA or scrambled version of the same sequence were incorporated into adeno-associated viral vectors and injected into the cNTS of rats. After 4 weeks, rats injected with the 5-HT<sub>1A</sub> …
-
The impact of ischaemic preconditioning on cerebrovascular function in healthy individuals.
… autoregulation, and autoregulation during hypercapnia. Methods: Nine healthy participants (age 32.6±11.1 yrs; BMI 25.9±4.4 kg/m2) underwent two laboratory visits; RIPC and SHAM. RIPC consisted of 4 x 5 min periods of cuff inflation (to 200 mmHg) around the upper arm, with cuff inflation …
-
Cerebrovascular and Ventilatory Function in Chronic Obstructive Pulmonary Disease
… and ventilatory responses to acute euoxic-hypercapnia in mild-moderate COPD patients, and the relationship between these physiological parameters, and markers systemic of oxidative stress. Second, the cerebrovascular responses during moderate cycling exercise are defined. The final three …
-
Accuracy of pulsed arterial spin labeling magnetic resonance imaging in the human brain : tag width and timing effects
… particularly during global challenges such as hypercapnia. In this study, the accuracy of QUIPSS II (Quantitative Imaging of Perfusion using a Single Subtraction - second version) ASL for measuring flow changes during a global flow perturbation (hypercapnia) was assessed.
-
A Study of Some Factors Influencing Vasopressin Release
… that such factors as emotional stress, hypoxia, hypercapnia and vagal stimulation may be involved in the cause of this condition. Recently Kramar, McCarthy, Grinnell and Dietz (2) demonstrated the presence of increased blood levels of vasopressin in patients suffering cardiac arrest. Experimental …
-
Autoregulation of Cortical Blood Flow in Response to Phenylephrine Induced Hypertension in the Normocapnic and Hypercapnic Cat
… conditions of normocapnia and, in some cases, hypercapnia. Arterial blood pressure and voltage output from the flow probe thermocouples were recorded continuously with a Physiograph-six monitor.</p> <p>We found the heated thermocouple flow probe to be useful for qualitative description and for …
-
Brain segmentation using endogenous contrast mechanism using breath holding fMRI signal for tissue characterization
… perturbation methods including breath holding, hypercapnia, inhalation of various gas mixtures, and injection of acetozolamyde has been used to study spatio-temporal changes in the fMRI signal intensity. Spatiotemporal changes corresponding to changes in cerebral blood flow (CBF), cerebral blood …
-
Neurons projecting to the paraventricular nucleus of the hypothalamus are activated and contribute to cardiorespiratory responses to systemic acute hypoxia
… attenuated ventilatory responses to hypoxia and hypercapnia. Data indicate that catecholamine neurons projecting to the PVN are critical for both peripheral and central chemoreflex respiratory responses.
-
Cardiovascular and respiratory reflex control systems in the regulation of pulmonary blood flow and ventilation during exercise
… of the muscle metaboreflex was observed in hypercapnia but not when breathing room air. Finally we found that increases in metabolic rate induced elevations in the ventilatory sensitivity to carbon dioxide. Overall these data suggest that the interplay between cardiovascular and respiratory …
-
The design and evaluation of the P₀.₁ method of assessing ventilatory drive
Hypercapnia and/or hypoxia normally cause hyperventilation, The sensitivity to hypercapnia and hypoxia and the resultant hyperventilation is reduced in a patient suffering from damped respiratory centre activity. The P 0.1 method is a modification of the rebreathing technique where a patient …
-
Exploring The Translational Clinical Value of Cerebrovascular Reactivity Assessments by Diffuse Correlation Spectroscopy
… protocols will agree well with the gold standard hypercapnia challenge. In Aim #2, I hypothesize that children with SCD experience markedly reduced CVR when compared to healthy children in response to a breath hold challenge. The ultimate outcome of this work lends support to the clinical value of …
-
Advancing the intravoxel incoherent motion model as a tool for quantifying brain microvascular health
… bootstrap aggregation estimator was used in a hypercapnia paradigm to attempt to demonstrate the proposed biomarkers in vivo. Finally, future work towards further validating and developing the proposed biomarkers in humans is described.
-
Development, testing, and application of quantitative oxygenation imaging from magnetic susceptibility by MRI
… and tested in 10 healthy volunteers during hypercapnia, i.e. breathing of low levels of CO₂. This respiratory challenge changes the baseline oxygenation state of the brain, enabling us to test whether our MRI method can detect different levels of OEF in vivo. We also show that OEF is reduced …
-
Measurement of Cerebral Metabolism and Vascular Function with Magnetic Resonance Imaging
… the effect of CO2 inhalation (also known as hypercapnia) on brain metabolism. A reduced CMRO2 was observed and this effect was further supported by findings using functional connectivity MRI and electroencephalography techniques. I also investigated the effect of O2 modulation (hypoxia and …
-
Assessing Pre-Frontal Cortex Oxygenation After Sport Concussion With Near Infrared Spectroscopy
… pathophysiology, near-infrared spectroscopy, hypercapnia
-
Neurovascular implications of life-long exposure to contact in rugby union; the link to cognition
… carbon dioxide (CVRCO2RANGE) was assessed using hypercapnia (CVRCO2HYPER) and hypocapnia (CVRCO2HYPO). Cognition was assessed via neuropsychometric tests and screened for mild cognitive impairment (MCI) using the Montreal Cognitive Assessment (MoCA). In-season notational analysis observed all …
-
Sleep/wakefulness versus urethane anesthesia: analogous arousal states for respiratory control?
… their ventilatory sensitivity to hypoxia and hypercapnia during sleep. The urethane-anesthetized animals also showed these same increases in ventilator sensitivity to hypoxia and hypercapnia as they moved into arousal states with synchronized cortical activity (State III). Like respiration, …
Page 1 of 2