Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “RESPIRATION”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 919 records · Page 51Linked to original sources
PubMed1980

[Cause of the appearance of cyanide-resistant respiration in the yeast Candida lipolytica].

Changes in the activity of the cell respiration of the yeast Candida lipolytica and its ATP, ADP, NADH, NAD+ pools during the development of the cyanide-resistant respiration were studied. A change-over of the yeast culture to the stationary growth phase conditioned by glucose exhaustion or aerobic incubation of the resting cells in the exponential growth phase without the exogenous carbon source were shown to be accompanied by: 1) decrease of the rate of oxygen consumption; 2) appearance of the cyanide-resistant respiration; 3) appearance of the benzhydroxamic acid-sensitive respiration; 4) appearance of stimulating dinitrophenol action on the rate of oxygen consumption; 5) increase in the ATP content and decrease of the ADP content in the cells. It was concluded that the appearance of the cyanide-resistant respiration is induced by the decrease of the activity of the respiratory chain due to the increase of the ATP concentration and the decrease of the ADP concentration in yeast cells. The functioning of the cyanide-resistant pathway of the electron transfer is one of the ways of NAD+ pool regulation in yeast cells.

Adenosine Diphosphate↗
PubMedDate not supplied

Respiration during wound regeneration and healing in the planarian worm Dendrocoelum lacteum.

The intensity of respiration of the body fragments of the planarian after its division anteriorly and posteriorly to the pharynx was studied. After division anteriorly to the pharynx regeneration takes place. During regeneration of the anterior fragment respiration increases in the first day after the operation and at the differentiation stage. During regeneration of the posterior fragments the oxygen consumption is unchanged. Healing of the wound after division of the planarian posteriorly to the pharynx is accompanied by intensification of respiration during the first two days after the operation. Comparison of regeneration and healing of the wound in fragments of equal weight shows that in the initial stages the intensity of respiration was the same. A significant difference is found at the stage of differentiation of the regenerating worm, when the regenerating fragments have a higher intensity of respiration than fragments unable to regenerate.

Animals↗
PubMed1994

[Stimulation of respiration in liver mitochondria by glucose in the absence of hexokinase activity. The effect of saccharose and several inhibitors of oxidative phosphorylation].

The effect of glucose on rat liver mitochondrial respiration after elimination of possible phosphorylation by mitochondrial hexokinase has been studied. It has been found that during isolation of mitochondria without washing and their subsequent washing with KCl-media glucose stimulates state 3 respiration but has no effect on the rate of state 4 respiration or on the uncoupler (2.4-dinitrophenol)-mediated respiration. The half-maximum effect is observed at the glucose concentration of about 2.4 mM. Washing of mitochondria with KCl or their isolation in a sucrose-containing medium without washing eliminates the stimulating effect of glucose. The sucrose present in the incubation medium suppresses the stimulating effect of glucose in a competitive manner. Oligomycin removes the stimulating effect when used at concentrations causing the suppression of state 3 mitochondrial respiration by 20%. Under these conditions carboxyatracytyloside markedly enhances the glucose effect. It is concluded that glucose controls the oxidative phosphorylation, acting as an adenine nucleotide translocator.

2,4-Dinitrophenol↗
PubMedDate not supplied

[Cyanide insensitive respiration of Candida lipolytica yeasts].

The effect of rotenone, antimycin A, oligomycin, 2,4,-DNP, and various subtrates on the appearance of cyanide-resistant respiration of Candida lipolytica yeast was studied. Rotenone inhibited the development of cyanide-resistant respiration, but did not prevent its origination. Antimycin A and oligomycin increased the rate of the appearance of cyanide-resistant respiration. If the resting yeast culture was incubated with 2,4-DNP, glucose, or glycerol, the development of the alternative pathway of electron transport was inhibited. Such substrates as alpha-glycerophosphate, citrate, and D,L-lactate had no effect on the time of appearance of cyanide-resistant respiration. Therefore, in the stationary growth phase, an alternative, cyanide-resistant pathway of electron transport results from the inhibition of the rate of electron transport in the respiration chain.

Antimycin A↗
PubMed1995

Historical total and respirable silica dust exposure levels in mines and pottery factories in China.

Historical exposure estimates of total dust and respirable silica were made in a recent nested case-referent study of lung cancer among mine and pottery workers in China. Exposure to total dust and respirable silica was assessed in 20 mines and 9 pottery factories. The average total dust concentration was 7.26 mg center dot m-3, with a range from 17.68 mg center dot m-3 in the 1950s to 3.85 mg center dot m-3 in the 1980s, while the average respirable silica dust was 1.22 mg center dot m-3, with a range from 3.89 mg center dot m-3 in the 1950s to 0.43 mg center dot m-3 in the 1980s. The highest respirable silica dust occurred in the underground mining operations (1.43 mg center dot m-3), particularly for manual drillers (9.03 mg center dot m-3). Among all facility types, tungsten mines had the highest respirable silica dust exposure (1.75 mg center dot m-3), while the lowest exposure occurred in copper-iron mines (0.32 mg center dot m-3).

Ceramics↗
PubMed1996

[Stimulation of mitochondrial respiration, induced by laser irradiation in the presence of rhodamine dyes].

The effect of micromolar concentration of rhodamine 123 (methylrhodamine) and ethyl and amyl esters of unsubstituted rhodamine on oxygen consumption by rat liver mitochondria was studied under irradiation by an argon laser (488 and 514 nm). Irradiation of mitochondria in the presence of rhodamine stimulates their respiration. Light-induced stimulation of respiration is not inhibited by free radical scavenger ionol and by inhibitor of the permeability transition pore cyclosporine A. Stimulation of respiration by moderate doses of radiation is reversed in the dark. Increase in radiation dose resulted in only partial reversal of stimulated respiration in the dark. Rhodamine efficacy in stimulation of mitochondrial respiration depends on its structure (amyl > ethyl > methylrhodamine).

Animals↗
PubMed1984

Reaction time course during weaning from respirator treatment.

Ten patients who developed disturbed mental function during respirator weaning were studied. They were investigated during respirator treatment and 1 h after start of spontaneous ventilation with continuous reaction time measurements and clinical ratings. During the spontaneous ventilation the reaction times increased and the patients experienced fatigue. PaCO2 was higher and PaO2 was lower than during respirator treatment. A significant correlation was found between individual differences of reaction times and arterial blood gas levels in the two conditions, whereas no general correlation between reaction times and arterial blood gas levels could be established. The findings must be considered tentative, but the results of this study indicate the value of continuous reaction time measurements for quantitative assessment of mental status during respirator treatment.

Adult↗
PubMed1989

Doppler evaluation of changing cardiac dynamics during Cheyne-Stokes respiration.

For the purpose of elucidating the mechanisms and/or effects of the cardiovascular changes occurring during Cheyne-Stokes respiration, we utilized Doppler echocardiography to determine intracardiac flow velocity profiles during the changing phases. Left ventricular inflow (LVI) and outflow (LVO) were examined in ten patients, nine with heart failure and one with a cerebrovascular accident. The mean LVI, peak early (E) and late diastolic (A) and LVO velocities were measured at the end of both the hyperpneic and apneic phases. The phasic hemodynamic changes observed during Cheyne-Stokes respiration by Doppler profile could be explained by the development of LV diastolic dysfunction and a decrease in LV stroke volume during the apneic phase of Cheyne-Stokes respiration. Alternatively, an increase in PCO2 during the apneic phase may increase pulmonary vascular resistance lowering preload and stroke volume, whereas during the hyperpneic phase, pulmonary vascular resistance is reduced with resultant increase in left ventricular preload and increase in stroke volume. Both theories are speculative and the precise hemodynamic changes associated with Cheyne-Stokes respiration requires further investigation.

Aged↗
PubMed1989

Combined effect of respirator-induced ventilation and superoxide dismutase in experimental brain injury.

The function-specific enzyme superoxide dismutase (SOD) was tested for its protective effect in severe experimental fluid-percussion brain injury (4.45 +/- 0.10 atm) in 30 of 60 randomly selected male Sprague-Dawley rats. A respirator was used only in the event of need. The number of animals with permanent resumption of spontaneous breathing (Type I respiratory response) remained essentially the same in each group. However, when Type II apnea (cannot maintain recovery) and Type III apnea (never recovers from the initial apnea) were terminated with a respirator, all rats with Type II responses from each group were successfully converted to a state of sustained spontaneous breathing. In contrast, only five (41.7%) of the 12 rats with Type III response were salvaged in the control group while five (83.3%) of six Type III rats in the SOD-treated group were saved. The results reveal the nature of the therapeutic effectiveness of superoxide radical scavengers in the overall outcome of head injury in this animal model. While SOD alone did not increase the number of spontaneous survivors, the drug shifted a number of animals from the critically injured rats with Type III respiratory response to the less critical Type II condition. Whereas induced respiration as the sole therapy in the control group lowered the mortality rate to 23.3%, respiratory assistance together with SOD treatment reduced the "mortality" to a single animal with Type III apnea (3.3%) which was alive but still required the respirator after 2 hours (p less than 0.001). The results show that respiratory assistance alone accounted for a 33% decrease in mortality rate and that SOD, given in addition to induced ventilation, further decreased mortality by 20%. Since SOD enzymes are reactively specific for superoxide, the increased survival rate of the brain-injured rat must have been due either to preventing or to minimizing pathophysiological changes, probably in the brain stem, caused by oxygen free radicals.

Animals↗
PubMed1975

[Additional gadget for new techniques of artifical respiration with the Bennett repirator PR 2, particulary suitable for use in children (author's transl)].

A new gadget for the Bennett PR 2 repirator is described which in modified form can also be used with other types of apparatus. It makes possible new techniques of artificial respiration like IPPB with PEEP or compensated PEEP, the gasp respiration with CPAP or CPAP by itself, in a simple way. In neonates one may do without the often problematical assisted respiration when weaning from the respirator. Further it is now possible to achieve sufficient warming and humidification of the gas mixture by using an auxiliary gas flow in the expiratory phase.

Child↗
PubMed1997

Amplitude demodulation of the electrocardiogram signal (ECG) for respiration monitoring and compensation during MR examinations.

A method for respiration monitoring during MR-sequences using the electrocardiogram signal (ECG) is presented. The basic principle is known in conventional patient monitoring and is based on the fact that the amplitude of the ECG-signal varies with respiratory motion. A demodulation of this "cardio-respiratory signal" yields a respiration curve that can be used for patient monitoring, triggering, or respiration compensation of MRI sequences. Since no drift is introduced by digital demodulation, this method is superior to analog signal processing. The proposed method was applied during MR examinations using an optically coupled ECG sensor that has the advantage of almost negligible interference due to the MR sequences (< < 10% of the main ECG signal). The respiration signal obtained is strongly correlated (r = 0.79 to 0.98) with the position of the diaphragm in inferior-superior direction measured during breath-holding MRI.

Adult↗
PubMed2006

Respiration-induced B0 field fluctuation compensation in balanced SSFP: real-time approach for transition-band SSFP fMRI.

In functional MRI (fMRI) the resonance frequency shift induced from respiration is a major source of physiological noise. In transition-band SSFP fMRI the respiration-induced resonance offset not only increases noise interference, it also shifts the activation band. This leads to a reduction in the contrast-to-noise ratio (CNR) and the potential for varying contrast levels during the experiment. A novel real-time method that compensates for the respiration-induced resonance offset frequency is presented. This method utilizes free induction decay (FID) phase information to measure the resonance offset. For compensation, one can update the resonant frequency in real time by changing the transmit RF pulse and receiver phases to track the measured offset. The results show decreased signal power in the respiration frequency band and increased numbers of activated voxels with higher Z-scores compared to uncompensated experiments.

Algorithms↗
PubMed1996

Correction for respiration artifact in pulmonary blood pressure signals of ventilated patients.

OBJECTIVE: To develop an algorithm that corrects pulmonary artery pressure signals of ventilated patients for the respiration artifact. The algorithm should test the validity of the pulmonary pressure signal and differentiate between the cyclic respiration artifact and true measurement artifacts. METHODS: The shape of each pulmonary pressure beat is described by eight characteristic features, including mean pressure value and the systolic and diastolic timing and pressure values. The features are corrected for the respiration artifact by fitting them in a least-squares sense on the first and second harmonics of the ventilator frequency. The corrected features are used by a signal validation algorithm, which adds a validity flag to each pressure beat. The validation algorithm rejects pressure beats with sudden changes in their shape but adapts itself when the changes persist. RESULTS: The performance of the correction and validation technique was evaluated using pulmonary artery pressure signals of 30 patients who were scheduled for open heart surgery. The algorithm correctly recognized as invalid data those pressure signals disturbed by coagulation, surgical manipulations, or flushes of the pressure line. The algorithm marked on average 77 +/- 11% of the pulmonary pressure beats as valid. CONCLUSIONS: The validation algorithm marked sufficient pressure beats as valid to update a trend display every 5 sec. The correction algorithm enabled the validation algorithm to differentiate between true measurement artifacts and the respiration artifact.

Algorithms↗
PubMed1990

Spectral analysis of heart rate variability signal and respiration in diabetic subjects.

The paper deals with methods of processing ECG and respiration signals which aim at detecting parameters whose values may be correlated to normal and diabetic subjects with or without cardiovascular autonomic neuropathy (CAN). Beat-to-beat R-R duration values of the ECG and discrete series of respiration are obtained from original signals using a recognition algorithm. Power spectrum analysis (autospectra, cross-spectra and coherence via autoregressive modelling) is carried out on segments of about 200 consecutive cardiac cycles. Spectral parameters of the R-R variability signal are obtained as follows: total power, powers of low-frequency (LF) and high-frequency (HF) components, power of the signal which is (or is not) coherent with respiration, in absolute or in percentage values. The experimental protocol considers 40 diabetic patients (21 of whom have diabetic neuropathy) and 14 normals in three different conditions: resting, standing and controlled respiration. The developed spectral parameters seem sensitive enough to differentiate between normal and pathological subjects. These parameters may constitute a quantitative means to be added to the classical diabetic tests for the diagnosis of cardiovascular autonomic neuropathy.

Adult↗
PubMed2003

Control of respiration by nitric oxide in Keilin-Hartree particles, mitochondria and SH-SY5Y neuroblastoma cells.

The pattern of cytochrome c oxidase inhibition by nitric oxide (NO) was investigated polarographically using Keilin-Hartree particles, mitochondria and human neuroblastoma cells. NO reacts with purified cytochrome c oxidase forming either a nitrosyl- or a nitrite-inhibited derivative, displaying distinct kinetics and light sensitivity of respiration recovery in the absence of free NO. Keilin-Hartree particles or cells, respiring either on endogenous substrates alone or in the presence of ascorbate, as well as state 3 and state 4 mitochondria respiring on glutamate and malate, displayed the rapid recovery characteristic of the nitrite derivative. All systems, when respiring in the presence of tetramethyl-p-phenylenediamine, were characterised by the slower, light-sensitive recovery typical of the nitrosyl derivative. Together the results suggest that the reaction of NO with cytochrome c oxidase in situ follows two alternative inhibition pathways, depending on the electron flux through the respiratory chain.

Animals↗
PubMed2003

Eating and breathing: interactions between respiration and feeding on solid food.

Chewed solid food accumulates in the oropharynx prior to swallowing. The mechanism for preventing aspiration during this interval is unknown, but may be related to respiration. The purpose of this study was to determine how eating, especially bolus formation in the pharynx, affects respiration. We examined nasal air pressures, masseter electromyography (EMG), and videofluorography (VFG) of four normal young adults eating 8 g each of banana and cookie (two trials each food). Resting respiration was recorded for 30 s before eating. Respiratory cycles (RCs) were classified as prefeeding, feeding (excluding cycles with included swallows), and swallowing cycles. RC duration was greater for swallowing than for feeding and prefeeding RCs (P < 0.001). There were up to three swallows in a single RC, but the increase in swallowing RC duration was greater than swallow duration. Swallow apnea began before bolus transport through the hypopharynx and ended as the bolus tail entered the esophagus. There were semirhythmic perturbations in nasal air pressure associated with masseter activity during chewing, suggesting that there was oronasal airflow during jaw closing via the velopharyngeal isthmus. The most important finding was that bolus aggregation in the valleculae usually occurred during an extended plateau in nasal air pressure following active expiration. This suggests that aspiration during eating is prevented by inhibiting respiration during bolus formation in the oropharynx.

Adult↗
PubMed2005

Effect of opioids on mechanoreflexive respiration control.

The effects of opioids (morphine and fentanyl) on the function of mechanoreceptive respiration regulatory loop were demonstrated. In most opioid-treated rats (74% cases) vagotomy was followed by apneustic respiration with inspiration pause. Excess of opioids in rat CNS produced minor disturbances in the respiration rhythm, but in the absence afferent input from the mechanoreceptors of respiratory pathways and lungs, pronounced periodic apneustic respiration with inspiration pauses developed. The opioidergic system is involved in the formation of respiratory rhythm, but had no appreciable effect on transmission of mechanoreceptive nerve pulses from respiratory pathways and the lungs to the respiratory center.

Analgesics, Opioid↗
PubMed1981

Suppressive influences from periaqueductal gray and nucleus raphe magnus on respiration and related reflex activities and on solitary tract neurons, and effect of naloxone.

Possible opiate-related descending influences from the periaqueductal gray matter (PAG) and nucleus raphe magnus (NRM) were tested on the activity of neural systems involved in respiration and related reflex functions in cats. Stimulation of PAG and NRM could powerfully suppress the simple buccopharyngeal reflexes of jaw-opening and tongue-protrusion and the more complex reflexes of coughing and swallowing; respiration in contrast appeared to be only weakly influenced. The reflexly induced responses of 57 single reflex interneurons recorded in the solitary tract nucleus (NST) could also be markedly suppressed by PAG and NRM conditioning stimulation. In contrast, the rhythmic activity of 30 respiratory neurons in NST was not abolished by PAG and NRM stimuli but most did show a decrease in the peak firing frequency of each rhythmic burst. The suppressive effect of PAG and NRM stimulation on the reflexes and NST reflex interneurons could be reduced by the intravenous administration of naloxone. These studies indicate that neuronal functions associated with respiration and respiratory-related activities can be suppressed by descending influences from PAG and NRM that are in part opiate-related. The observations add to the accumulating evidence that the raphe system is implicated in functions other than pain and its control, and they may also be relevant to clinical observations of opiate-induced effects on respiration and the cough reflex.

Animals↗