Search Results
Results 451 - 500 of 1024
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Jaques P A - - 2000
Ultrafine particles (< 0.10 microm in diameter) are present in great number in polluted urban air, thus posing a potential health risk. In this study, the total deposition fraction (TDF) of ultrafine aerosols with a narrow size distribution (number median diameter NMD = 0.04-0.1 microm and geometric standard deviation sigma(g) ...
Rassler B - - 2000
Coordination of the respiratory rhythm with the rhythm of limb movements has often been observed during rhythmical exercise (e.g. in locomotion). It is usually associated with changes in the respiratory time course, but not in the locomotor rhythm. Therefore, we hypothesised that in walking, the extent of coordination-related changes (CRC) ...
Halperin J - - 2000
Chasmagnathus granulatus is an estuarine crab which actively moves from subtidal to supratidal areas. To elucidate the possible existence of extrabranchial sites for aerial gas exchange, we measured respiratory and acid-base variables in animals with and without branchial water (controls and experimental crabs, respectively) during air exposure. An histological study ...
Jo W K - - 2000
This study included three different experiments for benzene exposures associated with active smoking. In the first experiment, the mean exhaled breath benzene concentrations measured 1 min after an active smoke ranged from 58.1 to 81.3 microgram/m(3), depending on the commercial cigarette brand, while those measured prior to an active smoke ...
Cardelli C - - 2000
The purpose of this study was to measure and compare the durations of exhalation (DE), inhalation (DI), and inhalatory apnea (DAI) expressed as percentage of stroke-cycle duration using two groups (more expert and less expert) of 6 front crawl swimmers each at near 100-m speed (high speed) and 800-m speed ...
Bagatto B - - 2000
The role of genetics on neonatal physiological variability was examined in the nine-banded armadillo (Dasypus novemcinctus). Since armadillos give birth to only monozygous quadruplets, the genetic variation within litters is essentially zero. Quadruplets born in captivity were isolated and weighed within 8 h of birth. Oxygen consumption (V.(O2)) was measured ...
Löffler R - - 2000
The behavior of the signal intensity in MRI of human lungs was investigated during inhalation of pure oxygen. Nine volunteers were examined, five using a breath-hold and four using a non-breath-hold technique. Four coronal slices were acquired in each volunteer using an inversion recovery turbo spin-echo sequence. The inversion time ...
Kluess H A - - 2000
Blood pressure and continuous electrocardiogram recordings were obtained from 12 participants during spontaneous breathing (SB1), dynamic handgrip exercise at 20% (HG(20)) of maximal voluntary contraction (MVC), and spontaneous breathing (SB2) and dynamic handgrip exercise at 60% (HG(60)) of MVC. Repeated-measures ANOVAs were used to examine the effects of the exercise ...
Morton R E - - 2000
The possible causes of excessive swallowing of air leading to bloating, which is common in Rett syndrome (RS), were investigated during feeding and at rest. Seven individuals with RS aged between 4 and 33 years (three with air bloat) underwent feeding videoflouroscopy and concurrent respiration monitoring. The results were compared ...
Bard R L - - 2000
PURPOSE: The purpose of this study was to determine the usefulness of a new graphical method for evaluating gas exchange (GE), as applied to three common averaging techniques used during rest, exercise, and recovery in patients with congestive heart failure (CHF). METHODS: Fifty patients' resting, exercise, and recovery GE graphs ...
Simons R S - - 2000
The mechanics of lung ventilation in frogs and aquatic salamanders has been well characterized, whereas lung ventilation in terrestrial-phase (post-metamorphic) salamanders has received little attention. We used electromyography (EMG), X-ray videography, standard videography and buccal and body cavity pressure measurements to characterize the ventilation mechanics of adult (post-metamorphic) tiger salamanders ...
Spengler C M - - 2000
The aim of the present study was to investigate whether the changes in breathing pattern that frequently occur towards the end of exhaustive exercise (i.e., increased breathing frequency, fb, with or without decreased tidal volume) may be caused by the respiratory work itself rather than by leg muscle work. Eight ...
Denny M - - 2000
Variability in inspired lung volume prior to speech is only partially accounted for by speech-related concerns such as the length and loudness of the planned utterance. Control mechanisms known to influence volume variability in non-speech breathing could potentially account for some of this variability, but only if they operate during ...
Kurabayashi H - - 2000
OBJECTIVE: To determine the importance of a breathing out into water exercise during subtotal immersion for emphysematous patients. DESIGN: Results of a respiratory function test and arterial blood gas analysis were examined to compare the programs of breathing exercise with and without the breathing out into water exercise. The breathing ...
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 ...
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