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Paoletti Elena - - 2005
Short-term elevated O3 reduces photosynthesis, which reduces stomatal conductance (g(s)) in response to increased substomatal CO2 concentration (Ci). Further exposure causes stomata to become sluggish in response to environmental stimuli. Exposure to elevated CO2 stimulates rapid stomata closure in response to increased Ci. This reduction in g(s) may not be ...
Arena Ross - - 2005
BACKGROUND: Peak oxygen consumption (V(O2)) and minute ventilation (V(E))/carbon dioxide production (V(CO2)) slope have been widely demonstrated to have strong prognostic value in patients with heart failure (HF). In the present study, we investigated the effect of HF etiology on the prognostic applications of peak V(O2) and Ve/V(CO2) slope. METHODS: ...
Xie Ailiang - - 2006
To investigate the contribution of the peripheral chemoreceptors to the susceptibility to posthyperventilation apnea, we evaluated the time course and magnitude of hypocapnia required to produce apnea at different levels of peripheral chemoreceptor activation produced by exposure to three levels of inspired P(O2). We measured the apneic threshold and the ...
Javadpour S M - - 2005
BACKGROUND: Carbon dioxide (CO2) retention during exercise is uncommon in mild to moderate lung disease in cystic fibrosis (CF). The ability to deal with increased CO2 is dependent on the degree of airflow limitation and inherent CO2 sensitivity. CO2 retention (CO2R) can be defined as a rise in P(ET)CO2 tension ...
Arena Ross - - 2006
BACKGROUND: Cardiopulmonary exercise testing (CPET) variables provide valuable prognostic information in the heart failure (HF) population. The purpose of the present study is to assess the ability of resting end-tidal carbon dioxide partial pressure (PETCO2) to predict cardiac-related events in patients with HF. METHODS: 121 subjects diagnosed with compensated HF ...
Pandit J J - - 2005
This paper reviews published studies (identified by a Medline-assisted search) on the effect of <or= 0.2 minimum alveolar concentration inhaled anaesthetic agents on the hypercapnic ventilatory response in healthy subjects. Each article was examined for the anaesthetic agent used, whether CO(2) was administered using a rebreathing or a steady state ...
Tingay D G - - 2005
OBJECTIVE: To assess the accuracy of measurements of end tidal carbon dioxide (CO2) during neonatal transport compared with arterial and transcutaneous measurements. DESIGN: Paired end tidal and transcutaneous CO2 recordings were taken frequently during road transport of 21 ventilated neonates. The first paired CO2 values were compared with an arterial ...
Luo Y M - - 2005
Assessment of neural respiratory drive may be useful in patients with chronic obstructive pulmonary disease (COPD) for diverse clinical and academic reasons. We hypothesised that the oesophageal diaphragm EMG during CO2 rebreathing and treadmill exercise could be used for this purpose. The oesophageal catheter consisted of nine consecutive recording electrode ...
Springer Clint J - - 2005
We examined the effects of elevated carbon dioxide concentration ([CO2]) on the relationship between light-saturated net photosynthesis (A(sat)) and area-based foliar nitrogen (N) concentration (N(a)) in the canopy of the Duke Forest FACE experiment. Measurements of A(sat) and N(a) were made on two tree species growing in the forest overstory ...
Heath Matthew - - 2005
In this investigation participants formulated a grip aperture (GA) consistent with the size of an object embedded within a Muller-Lyer (ML) figure prior to initiating visually guided grasping movements. The accuracy of the grasping response was emphasized to determine whether or not the visuomotor system might resolve the premovement bias ...
Joachim A - - 2005
Bioassays were developed and applied to test the role of eicosanoids and pH changes in ecdysis of Oesophagostomum dentatum. Exsheathment (80-100%) was achieved by subjecting third-stage larvae (L3) either to chlorine (hypochlorite assay) for 5 min or by incubating them in HCl followed by addition of NaHCO3 (pH-change assay) with ...
Entin Pauline L - - 2005
In animals that rely on the respiratory system for both gas exchange and heat loss, exercise can generate conflict between chemoregulation and thermoregulation. We hypothesized that in panting animals, hypocapnia during hyperthermic exercise reflects a reduction in the arterial CO2 tension (Pa(CO2)) set point. To test this hypothesis, five sheep ...
Badre Nicolas H - - 2005
Adult and larval insects are rapidly anesthetized by carbon dioxide (CO2); however, the mechanisms have not been addressed. In this study, we use larval Drosophila to investigate the actions of CO2 to explain the behavioral effects of rapid immobilization and cardiac arrest with acute exposure to CO2. To determine if ...
Hetz Stefan K - - 2005
The respiratory organs of terrestrial insects consist of tracheal tubes with external spiracular valves that control gas exchange. Despite their relatively high metabolic rate, many insects have highly discontinuous patterns of gas exchange, including long periods when the spiracles are fully closed. Two explanations have previously been put forward to ...
Davis Daniel P - - 2005
INTRODUCTION: Inadvertent hyperventilation has been documented during aeromedical transports but has not been studied following paramedic rapid sequence intubation (RSI). The San Diego Paramedic RSI Trial was designed to study the impact of paramedic RSI on outcome in patients with severe head injury. This analysis explores ventilation patterns in a ...
Bailey Jayne E - - 2005
The study of carbon dioxide (CO2) inhalation in psychiatry has a long and varied history, with recent interest in using inhaled CO2 as an experimental tool to explore the neurobiology and treatment of panic disorder. As a consequence, many studies have examined the panic-like response to the gas either using ...
Rostrup Egill - - 2005
The purpose of this study was to establish the relationship between regional CBF and CBV at normal, resting cerebral metabolic rates. Eleven healthy volunteers were investigated with PET during baseline conditions, and during hyper- and hypocapnia. Values for rCBF and rCBV were obtained using 15O-labelled water and carbon monoxide, respectively. ...
Melkonian Jeffrey - - 2005
Elevated (700 micromol mol-1) and ambient (350 micromol mol-1) CO2 effects on total ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activity, photosynthesis (A), and photoinhibition during 6 d at low temperature were measured on wild type (WT), and rbcS antisense DNA mutants (T3) of tobacco (Nicotiana tabacum L.) with 60% of WT total Rubisco ...
Turner Duncan - - 2004
Repeated trials of hypercapnic exercise [deltaPET CO2 = 7 (1) mmHg] augment the increase in inspired minute ventilation and tidal volume (V(T)) in the early phase of subsequent trials of unencumbered exercise alone. The increase in V(T) in the first 20 s of exercise was correlated to the increase in ...
Herndon Scott C - - 2004
In August 2001, the Aerodyne Mobile Laboratory simultaneously measured NO, NO2, and CO2 within 350 m of a taxiway and 550 m of a runway at John F. Kennedy Airport. The meteorological conditions were such that taxi and takeoff plumes from individual aircraft were clearly resolved against background levels. NO ...
Langenbuch M - - 2004
CO2 levels are expected to rise (a) in surface waters of the oceans as atmospheric accumulation continues or (b) in the deep sea, once industrial CO2 dumping is implemented. These scenarios suggest that CO2 will become a general stress factor in aquatic environments. The mechanisms of sensitivity to CO2 as ...
Taccone Paolo - - 2004
OBJECTIVE: The "helmet" has been used as a novel interface to deliver noninvasive ventilation without applying direct pressure on the face. However, due to its large volume, the helmet may predispose to CO2 rebreathing. We hypothesized that breathing with the helmet is similar to breathing in a semiclosed environment, and ...
Kouwenberg Lenny L R - - 2004
BACKGROUND AND AIMS: The inverse relationship between the number of stomata and atmospheric CO2 levels observed in different plant species is increasingly used for reconstructions of past CO2 concentrations. To validate this relationship, the potential influence of other environmental conditions and ontogenetical development stage on stomatal densities must be investigated ...
Gerritzen M A - - 2004
The purpose of this study was to investigate the suitability of gas mixtures for euthanasia of groups of broilers in their housing by increasing the percentage of CO2. The suitability was assessed by the level of discomfort before loss of consciousness, and the killing rate. The gas mixtures injected into ...
Ogino A - - 2004
The objectives of this study were to evaluate the environmental impacts of a beef-fattening system using the life-cycle assessment (LCA) method and to investigate the effects of feeding length on the LCA results. The functional unit was defined as one animal, and the stages associated with the beef-fattening life cycle, ...
Straus C - - 2004
The human respiratory neural drive has an automatic component (bulbospinal pathway) and a volitional component (corticospinal pathway). The aim of this study was to assess the effects of a hypercapnia-induced increase in the automatic respiratory drive on the function of the diaphragmatic corticospinal pathway as independently as possible of any ...
Howden Reuben - - 2004
Breathing carbon dioxide (CO2) is known to induce hypercapnic acidosis and to affect chemoreceptor regulation of the cardiovascular system. However, there is limited information in the literature regarding the effects of breathing CO2 upon tolerance to orthostatic stress where cardiovascular regulation is challenged. The purpose of this study was to ...
McGuire M A - - 2004
The respiration rate of a tree stem has commonly been estimated from measurements of CO2 efflux to the atmosphere. These estimates assume that all CO2 efflux originates from respiration of local tissues and that all CO2 produced by local tissues escapes to the atmosphere through the bark. However, dissolved CO2 ...
O'Dochartaigh Conor - - 2004
Elevated blood levels of Hcy (homocysteine) are associated with endothelial dysfunction in the systemic and coronary arterial beds. We wished to know if similar changes could be detected in the pulmonary circulation, using non-invasive tests. We studied ten normal young men aged 23-31 years, in whom acute hyperhomocysteinaemia was induced ...
Mortola Jacopo P - - 2004
In the avian embryo at term we measured the ventilatory response to hyperoxia, which lowers the chemoreceptor activity, to test the hypothesis that the peripheral chemoreceptors are tonically functional. Measurements of pulmonary ventilation (VE) were conducted in chicken embryos during the external pipping phase, at 38 degrees C, during air ...
Chambers Jeffrey Q - - 2004
Atmospheric changes that may affect physiological and biogeochemical processes in old-growth tropical forests include: (i) rising atmospheric CO2 concentration; (ii) an increase in land surface temperature; (iii) changes in precipitation and ecosystem moisture status; and (iv) altered disturbance regimes. Elevated CO2 is likely to directly influence numerous leaf-level physiological processes, ...
Bouillon Thomas - - 2004
BACKGROUND: Despite the ubiquitous use of propofol for anesthesia and conscious sedation and numerous publications about its effect, a pharmacodynamic model for propofol-induced ventilatory depression in the non-steady state has not been described. To investigate propofol-induced ventilatory depression in the clinically important range (at and below the metabolic hyperbola while ...
Persson M - - 2004
Carbon dioxide (CO2) insufflation in the cardiothoracic wound cavity is used in open-heart surgery for prevention of arterial air embolism. The objective of this study was to investigate if CO2 insufflation may influence the rate of airborne contamination of the cardiothoracic wound. This was studied in a cardiothoracic wound cavity ...
Risberg Jan - - 2004
BACKGROUND: Survival time within a disabled submarine (SUBSUNK) is dependant on atmospheric composition and proper design and use of emergency atmospheric control systems. The objective of this study was to investigate atmospheric changes and physiological responses during a SUBSUNK trial. METHODS: There were 18 volunteers who were restrained within a ...
Volk Yuri V - - 2004
Q switching of a diode-pumped Nd3+:KGd(WO4)2 laser at 1.35 microm by use of cobalt-doped magnesium- and zinc-aluminosilicate glass ceramics as saturable absorbers is demonstrated. Q-switching efficiency up to 40% has been obtained. Ground-state absorption cross sections for Co2+ ions at the wavelengths of 1.35 and 1.54 microm are estimated to ...
Prabhakar Nanduri R - - 2004
Peripheral chemoreceptors (carotid and aortic bodies) detect changes in arterial blood oxygen and initiate reflexes that are important for maintaining homeostasis during hypoxemia. This mini-review summarizes the importance of peripheral chemoreceptor reflexes in various physiological and pathophysiological conditions. Carotid bodies are important for eliciting hypoxic ventilatory stimulation in humans and ...
Davey Phillip A - - 2004
Averaged across many previous investigations, doubling the CO2 concentration ([CO2]) has frequently been reported to cause an instantaneous reduction of leaf dark respiration measured as CO2 efflux. No known mechanism accounts for this effect, and four recent studies have shown that the measurement of respiratory CO2 efflux is prone to ...
Hodges M R - - 2004
Our aim was to determine the effects of focal acidification in the raphe obscurus (RO) and raphe pallidus (RP) on ventilation and other physiological variables in both the awake and sleep states in adult goats. Through chronically implanted microtubules, 1) a focal acidosis was created by microdialysis of mock cerebrospinal ...
Holmes Mark D - - 2003
PURPOSE: To study whether respiratory alteration caused by vagal nerve stimulation (VNS) can change end-tidal carbon dioxide (EtCO2) levels. METHODS: We performed polygraphic recordings including capnographic monitoring during daytime sleep on adults with VNS therapy. RESULTS: Ten of 13 patients showed VNS-induced alterations in the frequency or amplitude of respiration. ...
Crosby Alexi - - 2003
The aims of this study were to determine 1) whether ventilatory adaptation occurred over a 5-day exposure to a constant elevation in end-tidal PCO2 and 2) whether such an exposure altered the sensitivity of the chemoreflexes to acute hypoxia and hypercapnia. Ten healthy human subjects were studied over a period ...
Mateika Jason H - - 2003
We hypothesized that patients with obstructive sleep apnea (OSA) have a different awake ventilatory response to carbon dioxide above and below eupnea compared with normal. Eight male subjects with OSA and control subjects matched for gender, race, age, height and weight voluntarily hyperventilated during wakefulness to reduce the partial pressure ...
Jack Sandy - - 2003
Idiopathic hyperventilation has been defined as a respiratory-related psychophysiological complaint. This study attempted to clarify relationships between psychological and physiological variables in this condition. Participants demonstrated increased anxiety, depression, and symptoms consistent with hyperventilation. This was associated with a reduced peripheral chemosensitivity (isocapnic hypoxic rebreathe; -0.84 +/- 0.5 min-1.%O2(-1)), which ...
Bouillon Thomas - - 2003
BACKGROUND: The C50 of remifentanil for ventilatory depression has been previously determined using inspired carbon dioxide and stimulated ventilation, which may not describe the clinically relevant situation in which ventilatory depression occurs in the absence of inspired carbon dioxide. The authors applied indirect effect modeling to non-steady state Paco2 data ...
Mongeluzi Donna L - - 2003
Previous studies in our laboratory have shown that a single exposure to 100% carbon dioxide (CO2) can serve as an effective unconditioned stimulus (US) in a Pavlovian aversive-context conditioning paradigm in rats. Although the US exposure parameters employed in the initial studies were sufficient for producing a context-specific enhancement of ...
Wood Helen E - - 2003
The ventilatory response to mild-to-moderate exercise in humans is isocapnic, or 'error-free'. It has been suggested that this response is learned over many repetitions of exercise through the process of minimising any deviations from normal in the blood gas tensions, as sensed by the chemoreceptors. However, relatively limited training programmes ...
Bailey J E - - 2003
The inhalation of carbon dioxide (CO2) is commonly used in patients and volunteers as a means of producing anxiety or panic. It is generally believed that patients with panic disorder are more vulnerable to the effects of CO2 than patients with other anxiety disorders or healthy volunteers and there is ...
Corne Stephen - - 2003
The hypoxic ventilatory response during hypocapnia has been studied with divergent results. We used volume-cycled ventilation in spontaneously breathing normal subjects to study their hypoxic ventilatory response under conditions of stable hypocapnia. Subjects were studied at three different levels of end-tidal (partial) carbon dioxide pressure (PETCO2), eucapnia and 6 and ...
Eynan Mirit - - 2003
BACKGROUND: Elevated arterial PCO2 (hypercapnia) is a known risk in diving with closed circuit breathing apparatus. In a retrospective study, we determined CO2 retention and the ability to detect CO2 in novice divers who were either CO2-recognition-trained subjects (TS) or untrained subjects (UTS). METHODS: Ventilatory and perceptual responses to variations ...
Bell Harold J - - 2003
Breathing increases abruptly at the start of passive exercise, stimulated by afferent feedback from the moving limbs, and declines toward a steady-state hyperpnea as exercise continues. This decline has been attributed to decreased arterial CO2 levels and adaptation in afferent feedback; however, the relative importance of these two mechanisms is ...
Casselbrant A - - 2003
BACKGROUND: The present study explores some aspects of the triggering of the acid-induced oesophago-salivary reflex. In addition to hydrogen ions, there are two acid-dependent molecules with messenger potential in the oesophageal lumen: CO2 and NO. The aim of this study was to clarify whether oesophageal NO and CO2 participate in ...
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