Search Results
Results 451 - 500 of 1010
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Marchenko V - - 2000
Respiratory and cardiovascular responses to microinjections (10 nl) of L-glutamate (10 mM) into the dorsal medulla were studied in spontaneously breathing urethane-anesthetized, adult male Wistar rats. A total of 10 patterns of respiratory and cardiovascular responses were observed: (1) hypotension alone; (2) hypotension and bradycardia; (3) hypotension and apnea; (4) ...
Levine M - - 2000
In periodic breathing, there are repeated cycles of bursts of breaths separated by pauses several seconds long. We consider the mechanics of periodic breathing in human infants using calibrated traces of tidal volume and esophageal pressure recorded during the first few days after delivery. Each cycle of periodic breathing was ...
Reed J Z - - 2000
The respiratory physiology, heart rates and metabolic rates of two captive juvenile male harbour porpoises (both 28 kg) were measured using a rapid-response respiratory gas analysis system in the laboratory. Breath-hold durations in the laboratory (12 +/- 0.3 s, mean +/- SEM) were shorter than field observations, although a few ...
Forster H V - - 2000
This review provides a summary and prospective on the importance of carotid/peripheral chemoreceptors to the control of breathing during physiologic conditions. For several days after carotid body denervation (CBD), adult mammals hypoventilate (+10 mmHg increase in Pa(CO(2))) at rest and during exercise and CO(2) sensitivity is attenuated by about 60%. ...
Greenley P L - - 2000
Airborne contaminants generated inside laboratory fume hoods during use leak into the breathing zone of the user. Concentration of the leakage is unknown and variable depending on laboratory design, work practices, arrangement of internal apparatus, face velocity, and sash height. Surrogate tracer gas tests have been developed using sulfur hexafluoride ...
Amis T - - 2000
PURPOSE: Mouthguards worn during sporting competition may influence oral airway flow dynamics and potentially increase airflow resistance during mouth breathing. METHODS: We measured oral airflow resistance (RO) in 10 normal subjects (four men, six women, age 29 +/- 3 yr, mean +/- SEM) wearing two different custom-made maxillary mouthguards. RESULTS: ...
Senthilmohan S T - - 2000
We show how the concentration of the breath gases ammonia, acetone, and isoprene vary with time during exercise using the new selected ion flow tube mass spectrometry (SIFT-MS) technique. The expired breath concentrations of ammonia, acetone and isoprene were observed within the range of 50-500, 100-1400 and 5-400 ppb, respectively. ...
Caruana-Montaldo B - - 2000
The control of breathing results from a complex interaction involving the respiratory centers, which feed signals to a central control mechanism that, in turn, provides output to the effector muscles. In this review, we describe the individual elements of this system, and what is known about their function in man. ...
Johansson A - - 1999
OBJECTIVE: A new photoplethysmographic (PPG) device for respiratory and heart rate monitoring has been evaluated in the neonatal care units at the University Children's Hospital of Uppsala, Sweden. The purpose of this study was to compare this new device with more established techniques, i.e., transthoracic impedance plethysmography (TTI) for monitoring ...
Troosters T - - 1999
In some patients exercise induces numerous complaints which cannot be attributed to an organic disorder, and which are suggestive of hyperventilation. The study was designed to investigate in this type of patient: 1) exercise capacity and muscle force; 2) breathing pattern and symptoms during maximal exercise and recovery; 3) relationships ...
Daggan R - - 1999
STUDY OBJECTIVES: To determine if the new Filta-Therm filter prevents contamination and allows the reuse of breathing circuit with considerable cost and environmental savings. DESIGN: Prospective study. PATIENTS: 52 ASA physical status I, II, III, and IV patients, aged 18 to 75 years. INTERVENTIONS: Each morning a new breathing circuit ...
van Nieuwenhoven M A - - 1999
BACKGROUND: The gastric emptying rate of liquids can be determined non-invasively using the [13C]-acetate breath test at rest. The aims of our study were to validate this test during physical exercise against the double-sampling method and to evaluate the time needed for intestinal absorption and the delay between absorption and ...
Morrell M J - - 1999
OBJECTIVES: The rostrolateral medulla (RLM) has been identified in animals as an important site of chemosensitivity; in humans such site(s) have not been defined. The aim of this study was to investigate the physiological implications of unilateral lesions in the lower brainstem on the control of breathing. METHODS: In 15 ...
Gargaglioni L H - - 1999
The nucleus isthmi (NI) is a mesencephalic structure of the amphibian brain. It has been reported that NI plays an important role in integration of CO2 chemoreceptor information and glutamate is probably involved in this function. However, very little is known about the mechanisms involved. Recently, it has been shown ...
Johnston S - - 1999
Ten normal and four moderate to severe stutterers participated in the study. Pleural (Ppl) and abdominal (Pab) pressure was studied using oesophageal and gastric balloon catheter systems and VL (VL) was studied using magnetometry. The classical Campbell diagram was modified by plotting Pab versus VL. In a preliminary study we ...
Supinski G - - 1999
The purpose of the present study was to determine whether it is possible to alter the development of fatigue and ablate free radical-mediated lipid peroxidation of the diaphragm during loaded breathing by administering oxypurinol, a xanthine oxidase inhibitor. We studied 1) room-air-breathing decerebrate, unanesthetized rats given either saline or oxypurinol ...
Peng C K - - 1999
We report extremely prominent heart rate oscillations associated with slow breathing during specific traditional forms of Chinese Chi and Kundalini Yoga meditation techniques in healthy young adults. We applied both spectral analysis and a novel analytic technique based on the Hilbert transform to quantify these heart rate dynamics. The amplitude ...
Donovan K J - - 1999
In the present study we compared the ventilatory performance whilst wearing self-contained breathing apparatus (SCBA) during exercise, of a group of male fire-fighters (FF, n = 8), with a matched group of male civilians (CV, n = 7). The mean (SEM) physiological characteristics of the subjects (FF vs CV) were: ...
Potter C R - - 1999
The purposes of this investigation were to quantify the noise component of child breath-by-breath data, investigate the major determinants of the breath-to-breath noise, and to characterise the noise statistically. Twenty-four healthy children (12 males and 12 females) of mean (SD) age 13.1 (0.3) years completed 25 min of steady-state cycle ...
Siegmund G P - - 1999
Ventilation and locomotion coupling (entrainment) has been observed and described in rowers during incremental exercise protocols but not during simulated race conditions. The purpose of this descriptive study was to examine ventilation and locomotion entrainment on a breath-by-breath and stroke-by-stroke basis in varsity male rowers during a maximal 2,000-m ergometer ...
Chinevere T D - - 1999
The aim of this study was to compare the effects of nasal splinting during different modes of breathing on breathing patterns and cardiorespiratory responses. Ten healthy subjects (4 males, 6 females) performed five maximal treadmill tests while breathing through the nose, nose + dilator, mouth, nose + mouth, and nose ...
Hoskin P J - - 1999
Capnometer measurements during 46 evaluable treatments in which patients were administered carbogen (95% O2, 5% CO2) have demonstrated that the mean inspired carbon dioxide level was 3.1% (range 0-4.7) and the mean inspired oxygen concentration was 70.6% (range 26.4-94). The explanation for this observation is leakage of air into the ...
Banzett R B - - 1999
We studied physiological and sensory effects of left cervical vagal stimulation in six adult patients receiving this stimulation as adjunctive therapy for intractable epilepsy. Stimulus strength varied among subjects from 0.1 to 2.1 microCoulomb (microC) per pulse, delivered in trains of 30-45 s at frequencies from 20 to 30 Hz; ...
Harty H R - - 1999
Multiple factors may contribute to the dyspnea associated with restrictive ventilatory disease (RVD). Simple models that examine specific features of this problem are likely to provide insight into the mechanisms. Previous models of RVD utilizing elastic loads may not represent completely the impact on pulmonary and chest wall receptors derived ...
Boussuges A - - 1999
Pulmonary oedema has been described in swimmers and self-contained underwater breathing apparatus (Scuba) divers. This study reports three cases of haemoptysis secondary to alveolar haemorrhage in breath-hold divers. Contributory factors, such as haemodynamic modifications secondary to immersion, cold exposure, exercise and exposure to an increase in ambient pressure, could explain ...
Krishnan, Bharath Subbiah
Minute ventilation (VE, and its pattern) is the result of an interaction between the drive to breathe (from the respiratory controller) and the mechanical properties of the respiratory system. While there is abundant information about the chemoreceptor based control of exercise V E, the present studies were designed to examine ...
Orfanos Popi - - 1999
Deep breathing and ambulation are used by physiotherapists for patients after surgery, however the precise effects of these on ventilation have not been investigated. This study was designed to compare the effects of deep breathing and ambulation on pattern of breathing in patients after upper abdominal surgery. A similar increase ...
Kurabayashi H - - 1999
Breathing exercises during immersion in 38 degrees C water were performed in 22 patients with bronchial asthma, pulmonary emphysema and constrictive pulmonary diseases. The patients entered a pool filled with 38 degrees C water to shoulder level. While standing, they breathed in deeply and breathed out slowly through the mouth ...
Spanel P - - 1999
We have used our selected ion flow tube mass spectrometric method (SIFT-MS) to study isoprene levels in the alveolar breath of 29 healthy volunteers during normal working hours at the varying states of nutrition occurring during this period. Quantification of the breath isoprene was achieved using O(2)(+) precursor ions to ...
Niles H P - - 1999
The objective of this double-blind clinical study was to investigate the effectiveness of a commercially available dentifrice containing triclosan and a copolymer (Colgate Total Toothpaste) for controlling long-term, i.e., seven-hour and overnight breath odor. In particular, a comparison was made between the level of control of breath odor provided by ...
McAuley J D - - 1998
The effect of deviations from temporal expectations on tempo discrimination was studied in 3 experiments using isochronous auditory sequences. Temporal deviations consisted of advancing or delaying the onset of a comparison pattern relative to an "expected" onset, defined by an extension of the periodicity of a preceding standard pattern. An ...
Flore P - - 1998
BACKGROUND AND PURPOSE: Biokinergia (BK) is a massage aimed at improving "biological" potential. An initial pilot study demonstrated that a BK session could alter blood lactate concentration during prolonged exercise. OBJECTIVE: To confirm the effect of BK on performance and physiological adaptations during maximal aerobic muscular exercise. METHODS: Two groups ...
Poh J - - 1998
We have compared the performance of a standard T-piece, a Venturi T-piece and a T-bag (T-piece with a small reservoir bag) for emergence with the laryngeal mask airway in 20 awake volunteers. FiO2, ETCO2 and FiCO2 were measured at oxygen flow rates of 2, 4 and 6 l.min-1 during three ...
Levitt M D - - 1998
The influence of the method alveolar air collection on measurements of trace gas concentration has received little attention. We measured the concentrations of H2, CH4, CO, and CO2 in sequential fractions of alveolar air collected with and without breath-holding. Without breath-holding, the concentration of these gases increased appreciably as increasing ...
Ritz T - - 1998
Little is known about total respiratory resistance (TRR) as a psychophysiological parameter in normal subjects. Therefore, we investigated TRR in 45 healthy students under multiple baseline conditions, isometric arm muscle tension and voluntary deep breathing (VDB). TRR was measured by the forced oscillation technique. In addition, heart rate (HR) as ...
Deakin C D - - 1998
The transthoracic current generated during defibrillation comprises a cardiac and extracardiac component. Changes in impedance of transthoracic pathways will alter the transmyocardial current and may thus affect the outcome from defibrillation. The lungs comprise a large component of extracardiac tissue but the effects of different respiratory gases on transthoracic impedance ...
Frappell P B - - 1998
Static respiratory mechanics were examined in the armadillo (Dasypus novemcinctus) and compared with allometric relationships newly derived for adult mammals from values in the literature. Normalised by body weight, chest wall compliance (Cw) in the armadillo is lower than predicted. Lung compliance (Cl) is also low in the armadillo, however ...
Joshi L N - - 1998
Ventilatory functions were studied in 36 male and 35 female subjects (mean age 18.5 years), who underwent six weeks course in forced breathing. Ventilatory functions were studied in the form of Forced Vital Capacity (FVC), Forced Expiratory Volume at the end of one second as % of FVC (FEV1%), Maximum ...
Dendo R I - - 1998
The effects of variations in cyclic breathing parameters (i.e., tidal volume and breath frequency) have been the subject of few studies devoted to the deposition of submicrometer aerosols in the human respiratory tract. Therefore, a series of experiments was performed to investigate whether the deposition efficiency (DE) of sidestream cigarette ...
Melissant C F - - 1998
In upper airway obstruction (UAO) the relationship between the degree of obstruction, exercise limitation and lung function indices is not well established. Therefore, we investigated in nine healthy subjects (age 36+/-9 yrs) the effects of two added resistances at the mouth (R1 = added resistance with 7.8 mm diameter; R2 ...
Petrini M F - - 1998
Breath-by-breath pulmonary function testing at the bedside is now available both with special-purpose stand-alone equipment and with the new generation of ventilators. The authors studied the variability of, reproducibility of, and ideal length of data collection for nine indices of pulmonary function that may be useful for ventilatory management, weaning, ...
Katagiri H - - 1998
Pulmonary complications after upper abdominal surgery are usually ascribed to temporary postoperative impairment of diaphragm function, which may not originate from intrinsic, structural injury but from reflex inhibition of diaphragm contractility. Spontaneous breathing is interrupted periodically by sighs, even after upper abdominal surgery. If postoperative dysfunction of the diaphragm arises ...
Medoff B D - - 1998
STUDY OBJECTIVES: Criteria used to define the respective roles of pulmonary mechanics and cardiovascular disease in limiting exercise performance are usually obtained at peak exercise, but are dependent on maximal patient effort. To differentiate heart from lung disease during a less effort-dependent domain of exercise, the predictive value of the ...
Maeda T - - 1998
This study aimed to investigate the effects of hyperoxic gas breathing on the disappearance of blood lactate after exercise in two groups having different physical fitness and to determine the most effective O2 concentration in consideration of workload. Our previous study has demonstrated that hyperoxic gas breathing brought out different ...
Kraman S S - - 1998
The spectra of sounds recorded over the trachea of adults typically reveal peaks near 700 and 1500 Hz. We assessed the anatomical determinants of these peaks and the conditions contributing to their presence. We studied five adult subjects with normal lung function, measuring sounds at the suprasternal notch and on ...
Cotton D J - - 1998
BACKGROUND: Although centrilobular emphysema, and small airway, interstitial and alveoli inflammation can be detected pathologically in the lungs of smokers with relatively well preserved lung function, these changes are difficult to assess using available physiological tests. Because submaximal single breath washout (SBWSM) manoeuvres improve the detection of abnormalities in ventilation ...
Johnson J S - - 1998
Peak oxygen consumption is a commonly accepted criterion in patient selection for cardiac transplantation. To determine the effect of various gas exchange sampling intervals on the variability of peak oxygen consumption, 15 consecutive patients evaluated for cardiac transplantation performed maximal treadmill testing using a ramped protocol. Oxygen consumption was measured ...
Bonsignore M R - - 1998
PURPOSE: To assess whether entrainment of breathing (E) during exercise: 1) differed according to the test protocol in well-trained triathletes, and 2) improved ventilatory efficiency during exercise. METHODS: Eight triathletes performed three incremental tests until exhaustion: while cycling (CE), while running at increasing grade and constant speed (increasing GRADE) and ...
Heller H - - 1998
We determined the pulmonary diffusing capacity (DL) for 18O-labeled CO2 (C18O2) and nitric oxide (NO) to estimate the membrane component of the respective gas conductances. Six anesthetized paralyzed rabbits were ventilated by a computerized ventilatory servo system. Single-breath maneuvers were automatically performed by inflating the lungs with gas mixtures containing ...
Gilbert T B - - 1998
Performance of a wind instrument requires appreciable lung volume and diaphragmatic mechanical force, skilled breath control, adequate patency and humidity of air passages, and precise coordination of the oropharyngeal cavity. Depending on the instrument class, variable rates of air flow, pressure, and duration are necessary to produce optimal tone quality. ...
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