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At least 37 records · Page 2Linked to original sources
PubMed2004

A whole-genome scan for 24-hour respiration rate: a major locus at 10q26 influences respiration during sleep.

Identification of genes causing variation in daytime and nighttime respiration rates could advance our understanding of the basic molecular processes of human respiratory rhythmogenesis. This could also serve an important clinical purpose, because dysfunction of such processes has been identified as critically important in sleep disorders. We performed a sib-pair-based linkage analysis on ambulatory respiration rate, using the data from 270 sibling pairs who were genotyped at 374 markers on the autosomes, with an average distance of 9.65 cM. Uni- and multivariate variance-components-based multipoint linkage analyses were performed for respiration rate during three daytime periods (morning, afternoon, and evening) and during nighttime sleep. Evidence of linkage was found at chromosomal locations 3q27, 7p22, 10q26, and 22q12. The strongest evidence of linkage was found for respiration rate during sleep, with LOD scores of 2.36 at 3q27, 3.86 at 10q26, and 1.59 at 22q12. In a simultaneous analysis of these three loci, >50% of the variance in sleep respiration rate could be attributed to a quantitative-trait loci near marker D10S1248 at 10q. Genes in this area (GFRA1, ADORA2L, FGR2, EMX2, and HMX2) can be considered promising positional candidates for genetic association studies of respiratory control during sleep.

Adult↗
PubMedDate not supplied

[Effect of oxygen inhalation on the respiration function during exercise under conditions of added resistance to respiration].

Experiments were performed to investigate the effect of added resistance to inspiratory, expiratory and inspiratory-expiratory respiration on lung ventilation and pACO2 during exercise when breathing air or oxygen. Increase of resistance to respiration, particularly inspiratory-expiratory; reduced the work-induced growth of ventilation which caused pACO2 to increase. Oxygen inhalation aggravated those shifts significantly. The adverse effect of hyperoxia on the respiration function when exercise was combined with added resistance to respiration seems to be associated with inhibition of the respiration center produced by the lack of hyperoxid stimulation.

Adult↗
PubMed1985

[Histomorphologic lung findings in long-term artificial respiration with special reference to extreme continuous artificial respiration using pure oxygen].

The respirator lung is characterized histologically in the first exudative phase by capillary congestion, intra-alveolary edema, hyaline membranes and in most cases by concomitant inflammatory alterations. In the following irreversible phase, fibrous organization processes dominate and show a variable tendency towards pulmonary fibrosis. In 27 cases with long-term artificial respiration from 4 days to 12 weeks, mainly the proliferative alterations were investigated. In 18 cases, the histopathological findings indicated fibrosis of the alveolar septa with disseminated distribution. In 9 cases, focal fibrosis with obliterations of alveoli prevailed. The extent of pathological results in the lungs does not correlate with the duration of artificial respiration. In cases of artificial respiration with pure oxygen, there is a special toxic component, which is illustrated by a young woman with polytraumatism who was administered artificial respiration for 5 weeks with pure oxygen. She died from respiratory insufficiency with severe pulmonary fibrosis. As different pathogenetic factors may cause irreversible pulmonary fibrosis, histomorphological classification is difficult later and, moreover, forensic problems result.

Adolescent↗
PubMed1981

Membrane potentials in respiring and respiration-deficient yeasts monitored by a fluorescent dye.

Changes in fluorescence of 3,3'-dipropylthiodicarbocyanine iodide which had been equilibrated with suspensions of the wild-type yeast Saccharomyces cerevisiae and of respiration-deficient mutants were followed. The changes have been attributed to changes of yeast membrane potentials, since the fluorescence with wild-type yeast could be affected in a predictable manner by uncouplers and the pore-forming agent nystatin. As in other systems, a rise of steady-state fluorescence was ascribed to depolarization and a drop of the fluorescence to hyperpolarization. (1) A considerable rise in steady-state fluorescence was brought about by addition of antimycin A or some other mitochondrial inhibitors to respiring cells. A major part of the composite membrane potential monitored in intact yeast cells appeared to be represented by the membrane potential of mitochondria. (2) Addition of D-glucose and of other substrates of hexokinase, including non-metabolizable 2-deoxy-D-glucose, induced a two-phase response of fluorescence, indicating transient depolarization followed by repolarization. Such a response was not elicited by other sugars which had been reported to be transported into the cells by a glucose carrier or by D-galactose in galactose-adapted cells. The depolarization was explained by electrogenic ATP exit from mitochondria to replenish the ATP consumed in the Hexokinase reaction and the repolarization by subsequent activation of respiration. (3) In non-respiring cells only a drop in fluorescence was induced by glucose and this was ascribed to an ATP-dependent polarization of the plasma membrane. (4) Steady-state fluorescence in suspensions of respiration-deficient mutants, lacking cytochrome a, cytochrome b, or both, was high an remained unaffected by uncouplers and nystatin. This indicates that membranes of the mutants may have been entirely depolarized. A partial polarization, apparently restricted to the plasma membrane, could be achieved by glucose addition.

Antimycin A↗
PubMed2004

Short-term variations in delta(13)C of ecosystem respiration reveals link between assimilation and respiration in a deciduous forest.

We present a comprehensive dataset of hourly, daily, and monthly measurements of carbon isotope measurements of CO(2) in canopy air from a temperate deciduous forest with the aim to identify the relevance of short-term variations in the isotopic signature of ecosystem respiration (delta(13)C(R)) and to understand its underlying physiological processes. We show that during daytime low vertical mixing inside the canopy can lead to decoupling of the air in the lower and upper canopy layer resulting in large spatial variation of delta(13)C in CO(2) of canopy air. Intercept of Keeling Plots also showed large temporal variation (3.8 per thousand) over the course of the day demonstrating that intercepts can differ between day and night and suggesting that choosing the right time for sampling is essential to capture the isotopic signature of ecosystem respiration (delta(13)C(R)). delta(13)C(R) as obtained from night-time measurements showed large variation of up to 2.65 per thousand on a day-to-day basis, which was similar to the observed variation of delta(13)C(R) over the seasonal cycle (3.08 per thousand). This highlights the importance of short-term physiological processes within ecosystems for the isotopic composition of CO(2) in the atmosphere, not reflected by bulk plant and soil organic samples. At daily and monthly time scales, delta(13)C(R) increased with increasing ratio of vapour pressure deficit to photosynthetically active radiation, measured 4-5 days before. This suggests that ecosystem respiration was isotopically linked to assimilation. Furthermore, assimilates recently fixed in the canopy seem to form a labile carbon pool with a short mean residence time that is respired back to the atmosphere after 4-5 days.

Air↗
PubMed1980

Respirator protection factors: Part II-protection factors of supplied-air respirators.

Protection Factors provided by 25 NIOSH approved supplied-air respirators were determined while the devices were worn by a panel of test subjects anthropometrically selected to represent adult facial sizes. Polydispersed DOP aerosol was used for respirator fit tests on continuous flow, demand, and pressure-demand respirators. Based on facepiece leakage measurements it appears that demand-type respirators should neither be used nor approved. The highest level of protection was provided by pressure-demand devices.

Evaluation Studies as Topic↗
PubMed1977

Inhibition of the Development of Induced Respiration and Cyanide-insensitive Respiration in Potato Tuber Slices by Cerulenin and Dimethylaminoethanol.

The interdependence of the development of wound-induced respiration and membrane-related phospholipid biosynthesis in potato tuber (Solanum tuberosum var. Russet) slices was established by the use of agents which selectively affect lipid and phospholipid synthesis. Cerulenin, a specific inhibitor of de novo fatty acid synthesis, inhibited the ultimate development of wound-induced respiration and of cyanide resistance only when given in the critical first 10 to 12 hours of slice aging. Similarly, when slices were exposed to the choline analogue dimethylaminoethanol within the first 10 hours, the phospholipid composition of the membrane lipids was drastically altered, the wound-induced respiration in a 24-hr period was substantially curtailed, and the development of cyanide insensitivity was sharply inhibited. These observations indicate that time-restricted membrane-related phospholipid synthesis is prerequisite to the development of wound-induced respiration and concurrent cyanide insensitivity.

Journal Article↗
PubMed1992

Stimulation by thyroid hormone of coupled respiration and of respiration apparently not coupled to the synthesis of ATP in rat hepatocytes.

Maximal rates of O2 uptake by hepatocytes from hypothyroid, euthyroid, and hyperthyroid rats, in the absence of uncoupling agents or ionophores, were achieved by simultaneously stimulating ureogenesis and gluconeogenesis. Rates were increased by pretreatment of the donor animals with thyroid hormone. Only a minor part of the increase could be attributed to stimulation of the activity of plasma membrane (Na+ + K+)-ATPase. No synthesis of glycogen occurred, nor was there any evidence of pyruvate cycling under the conditions used, thus ruling out these processes as potential sources of ATP turnover. Calculation of the O2 uptake necessary to satisfy the energy requirements of gluconeogenesis and ureogenesis, based on anticipated ATP demand and an assumed P:O ratio of 3:1, invariably yielded a theoretical quantity that was less than the experimentally measured increase in O2 uptake. The difference between measured and calculated rates of respiration, possibly representing noncoupled respiration, was related to the thyroid status of the animal, being greatest in cells from hyperthyroid rats. In another experimental approach the O2 uptake associated with ATP synthesis was inhibited by the addition of oligomycin to hepatocytes incubated in the presence of substrates, thus abolishing ATP-coupled respiration. The magnitude of the ATP-coupled as well as the residual respiration was increased in response to thyroid hormone. Thyroid hormone increased the turnover of intramitochondrial ATP. These results imply that a considerable portion of the thermogenic effect of thyroid hormone may be mediated by a stimulatory action on metabolism not directly associated with extramitochondrial ATP-dependent synthetic processes.

Adenosine Triphosphate↗
PubMed2004

Phylogenetic analysis of proteins associated in the four major energy metabolism systems: photosynthesis, aerobic respiration, denitrification, and sulfur respiration.

The four electron transfer energy metabolism systems, photosynthesis, aerobic respiration, denitrification, and sulfur respiration, are thought to be evolutionarily related because of the similarity of electron transfer patterns and the existence of some homologous proteins. How these systems have evolved is elusive. We therefore conducted a comprehensive homology search using PSI-BLAST, and phylogenetic analyses were conducted for the three homologous groups (groups 1-3) based on multiple alignments of domains defined in the Pfam database. There are five electron transfer types important for catalytic reaction in group 1, and many proteins bind molybdenum. Deletions of two domains led to loss of the function of binding molybdenum and ferredoxin, and these deletions seem to be critical for the electron transfer pattern changes in group 1. Two types of electron transfer were found in group 2, and all its member proteins bind siroheme and ferredoxin. Insertion of the pyridine nucleotide disulfide oxidoreductase domain seemed to be the critical point for the electron transfer pattern change in this group. The proteins belonging to group 3 are all flavin enzymes, and they bind flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN). Types of electron transfer in this group are divergent, but there are two common characteristics. NAD(P)H works as an electron donor or acceptor, and FAD or FMN transfers electrons from/to NAD(P)H. Electron transfer functions might be added to these common characteristics by the addition of functional domains through the evolution of group 3 proteins. Based on the phylogenetic analyses in this study and previous studies, we inferred the phylogeny of the energy metabolism systems as follows: photosynthesis (and possibly aerobic respiration) and the sulfur/nitrogen assimilation system first diverged, then the sulfur/nitrogen dissimilation system was produced from the latter system.

Amino Acid Sequence↗
PubMed2002

Development of a continuous respiration olfactometer for odorant delivery synchronous with natural respiration during recordings of brain electrical activity.

The continuous respiration olfactometer (CRO) was designed as a respiration-synchronous method for delivering odorants during recordings of brain electrical activity, providing control and monitoring of the timing of the delivery as well as the quantities of odorant involved. The CRO incorporates a purpose-built electronic system designed with very specific temporal and quantitative characteristics, and is composed of four main parts: the respiratory monitoring apparatus, the odorant/air delivery system, the serial interface device and the respiratory monitoring software. Tests were undertaken to determine the performance of the system with reference to the accuracy and precision of timing and control of odorant delivery. Tests were also undertaken to determine the effects of variations in natural respiration between subjects on the capability of the respiratory monitoring system, using a group of 50 subjects, to test the success of a variable gain control to optimize the range of the digitized respiratory output. The delivery system was able to provide information concerning quantities of air or odorant delivered, and the stimulus timing information required for integration with neurophysiological recording techniques.

1-Butanol↗
PubMed2004

Chlorate and nitrate reduction pathways are separately induced in the perchlorate-respiring bacterium Dechlorosoma sp. KJ and the chlorate-respiring bacterium Pseudomonas sp. PDA.

The effect of nitrate on perchlorate and chlorate reduction by perchlorate-respiring bacteria (PRB), and on chlorate reduction by chlorate-respiring bacteria (CRB), is not well understood, particularly with respect to the induction of pathways used to degrade these different chemicals. Based on kinetic data obtained in a series of batch tests, we determined that perchlorate respiratory enzymes were inducible (by chlorate or perchlorate) and separate from those used for denitrification by PRB strain Dechlorosoma sp. KJ. Aerobically grown cultures of KJ had lag times of greater than 0.3-2 days when transferred to a medium containing only perchlorate, chlorate, or nitrate as an electron acceptor. There were no lag times for transfers between identical media. Washed cells reduced very little nitrate (<10%) when grown only on chlorate or perchlorate. When grown on nitrate, they degraded little chlorate or perchlorate. The same lack of activity with these electron acceptors was also observed using cell extracts and methyl viologen as an electron carrier, indicating a lack of reactivity was not due to failure of the chemical to diffuse into the cell. Taken together, these results indicated that enzymes for perchlorate and nitrate reduction are separately expressed in strain KJ. The presence of small amounts of nitrate in contaminated groundwater may actually help to increase rates of perchlorate reduction once the nitrate is completely removed. When strain KJ was pre-grown on nitrate and perchlorate, perchlorate degradation (in the absence of nitrate) was more rapid compared to cells grown only on perchlorate. Pseudomonas sp. PDA was unable to degrade perchlorate or grow using nitrate, and the induction of enzymes necessary for chlorate respiration differed for strains KJ and PDA. While chlorate reductase and chlorite dismutase activity were induced in KJ by chlorate or perchlorate under anaerobic conditions, these two enzymes were constitutively expressed by PDA under anaerobic and aerobic conditions independent of the presence of chlorate. To our knowledge, this is the first report of constitutive expression of both chlorate reductase and chlorite dismutase in a bacterium.

Bacteria, Anaerobic↗
PubMed1967

Effect of carbonyl cyanide m-chlorophenylhydrazone on respiration and respiration-dependent phosphorylation in Escherichia coli.

1. The interference mechanism of carbonyl cyanide m-chlorophenylhydrazone with the respiratory process and with phosphorylation coupled to respiration has been investigated in resting cells of Escherichia coli. 2. Preincubation of the cells with carbonyl cyanide m-chlorophenylhydrazone in the absence of substrate caused strong inhibition of succinate oxidation. The inactivation of the respiratory system proved to be time-dependent and temperature-dependent and could be arrested by adding the substrate. Inhibition of incorporation of (32)P into acid-soluble organic phosphate esters exceeded the inhibition of oxygen uptake. 3. In contrast with succinate, the rate of oxidation of glucose was increased by carbonyl cyanide m-chlorophenylhydrazone. The sensitivity of other substrates to the inhibitor was less than that of succinate. 4. Various observations are described in support of the view that respiratory inhibition induced by carbonyl cyanide m-chlorophenylhydrazone is a result of its interference with ATP synthesis. The capacity of a given substrate to increase intracellular ATP concentration appeared to be directly related to its resistance to inhibition. In cell-free extracts carbonyl cyanide m-chlorophenylhydrazone still suppressed (32)P incorporation but had no effect on respiration. 5. Carbonyl cyanide m-chlorophenylhydrazone-induced stimulation of glucose oxidation and the acceleration of succinate oxidation by ADP or AMP in cells rendered permeable to nucleotides are tentatively interpreted as an indication that a certain part of respiration in E. coli is under phosphate-acceptor-mediated control.

Adenine Nucleotides↗
PubMed1989

Sulfide-Resistant Respiration in Leaves of Elodea canadensis Michx: Comparison with Cyanide-Resistant Respiration.

The rate of dark O(2) uptake of Elodea canadensis leaves was titrated with either cyanide or sulfide in the presence and in the absence of 5 millimolar salicylhydroxamic acid (SHAM), an inhibitor of the alternative oxidase. The inhibition of O(2) uptake by SHAM alone was very small (3-6%), suggesting that actual respiration mainly occurred through the cytochrome pathway. O(2) uptake was slightly stimulated by cyanide at concentrations of 50 micromolar or higher, but in the presence of SHAM respiration was strongly suppressed. The effects of sulfide on O(2) uptake were similar to those of cyanide, except that the percent stimulation of O(2) uptake by sulfide alone was somewhat higher than that of cyanide. However, the estimates of the capacity of the alternative pathway were similar with both inhibitors. Another difference is that maximal inhibition of respiration in the presence of SHAM was observed with lower concentrations of sulfide (50 micromolar) than cyanide (250 micromolar). The results suggest that sulfide can be used as a suitable inhibitor of cytochrome c oxidase in studies with intact plant tissues, and that sulfide does not apparently inhibit the alternative oxidase.

Journal Article↗
PubMed2002

Level of silica in the respirable dust inhaled by dental technicians with demonstration of respirable symptoms.

Dental technicians are exposed to various dusts in working laboratories. This study was conducted to measure level of silica in the respirable dust generated from dental fixed prosthodontics manufacturing processes using Fourier Transform Infrared Spectroscopy (FTIR), and to compare their occurrence of respiratory symptoms with that of non-dental hospital workers (control group). Respirable dusts were personally sampled from dental technicians working at dental laboratories in Seoul Korea according to NIOSH Method 0600. Fifty personal samples were obtained during porcelain or polishing process and weighed by a gravimetric method. Concentration of respirable dust was 651 +/- 548 microg/m3 (Mean +/- SD) with highest concentration of 2,874 microg/m3 during the porcelain process and 725 +/- 414 microg/m3 with highest concentration of 1,764 microg/m3 during the polishing process. Concentration of silica was 6.51 +/- 6.07 microg/m3 with 18.85 microg/m3 highest and 14.88 +/- 11.21 microg/m3 with 50.98 microg/m3 highest for the porcelain and polishing process, respectively. Level of silica contents in the dust was 0.81% and 1.66% for the porcelain and polishing process, respectively. The level of silica contents and silica concentration were significantly different between the two processes. Comparing prevalence of respiratory symptoms between non-smoking seventeen dental technicians and thirty-five control workers, wheezing and rhinorrhea were significantly more manifested in the dental technicians than the controls. Total frequency of respiratory symptoms was also significantly higher in the dental technicians than the controls.

Adult↗
PubMed1981

Metabolic relationships between lipolysis and respiration in rat brown adipocytes. The role of long chain fatty acids as regulators of mitochondrial respiration and feedback inhibitors of lipolysis.

The calorigenic action of norepinephrine in isolated brown adipocytes was selectively mimicked by theophylline, dibutyryl cyclic AMP, and the principal fatty acids known to be present in the acyl moieties of brown adipose tissue triglycerides (palmitic, oleic, and linoleic acids). The stimulatory effects of fatty acids were entirely reversible, occurred at physiological concentrations, and were critically dependent upon the molar ratio of extracellular fatty acids to albumin. The calorigenic potency of fatty acids increased with their chain length. The apparent synchrony between the switching "on and off" of lipolysis and respiration by norepinephrine and propranolol indicated that the two phenomena are functionally inter-related and that they are both mediated by beta-adrenoreceptors. Respiratory stimulation by palmitic acid was accompanied by an inhibition of glycerol release suggesting that fatty acids retroinhibit lipolysis while simultaneously activating respiration. Studies with 2-tetradecylglycidic acid, oligomycin, and uncouplers of oxidative phosphorylation support the view that fatty acids exert their calorigenic effects by increasing mitochondrial proton permeability and by simultaneously serving as substrates for beta-oxidation via carnitine-dependent pathways. Since fatty acids mimicked the calorigenic action of norepinephrine even when beta-adrenoreceptors were blocked by propranolol, it is concluded that cyclic AMP controls respiration indirectly, most probably by modulating lipolysis. It is suggested that endogenous long chain fatty acids released in consequence of cyclic AMP activation of lipolysis play a fundamental role in the control of brown adipose tissue metabolism by self-regulating lipolysis and by serving as physiological modulators of mitochondrial oxygen consumption.

Adipose Tissue, Brown↗
PubMed1983

[A model for standardized treatment and therapeutic evaluation of severe ARDS. PIF and AaDO2 quotient with a demand-adapting respirator and a conventional respirator during ARDS].

In order to achieve a uniform, easy to teach and to manage respiratory management in severe adult respiratory distress syndrome (ARDS) a combined treatment--called "step by step scheme"--was settled. It was aimed towards a regulation of the arterial blood oxygen tension at levels between 90 and 130 mmHg and this was achieved by combination of PEEP and IRV in order to minimize the inspiratory fraction of oxygen. Nine patients underwent this schedule and Benzer's AaDO2 quotient as an estimation of lung function as well as PIF (PEEP X I:E X FiO2) as quantifying parameter for the "strength" of the respirator are calculated. AaDO2 Quotient showed no statistically significant differences but PIF performed a clearly marked day of maximum respiratory support during the clinical course. This seems to be a confirmation that a variable defined by therapeutic procedures may also be an estimation of a certain degree of sickness as a pure diagnostic parameter. In plotting AaDO2 quotient versus PIF characteristically formed loops result. These loops give some evidence about the interactions between improving or worsening ARDS and properly adjusted therapeutic efforts by means of a respirator. The diagram may be also helpful in deciding conventional respirator settings or weaning procedures and show marks, where one might consider to treat by new techniques like High Frequency Ventilation, extracorporeal devices or arteriovenous hemofiltration.

Adult↗
PubMed1989

Evidence for a respiration-modulated cholinergic action on the activity of medullary respiration-related neurons in the rabbit. An iontophoretic study.

Effects of the iontophoretically administered cholinergic agonists acetylcholine, bethanechol and DMPP on the activity of medullary respiration-related neurons were examined in urethane-anaesthetized rabbits. Inhibitory effects prevailed over excitatory effects. Analysis of cholinergic effects by cycle-triggered averaging revealed three major types of neuronal responses: (i) constant alterations of spike-density throughout the whole period of activity ("constant effects"), (ii) effects increasing during the progression of the burst of discharge or effects restricted to a particular fraction of the burst ("phasic effects") and (iii) effects which were characterized by an excitation during one respiratory phase and an inhibition during the other phase ("bi-phasic effects"). The latter type of effects was observed in phase-spanning respiration-related neurons. Phasic effects were mainly observed in inspiration-related neurons which were predominantly inhibited by stimulation of muscarinic receptors. Inspiratory R beta-neurons in no case were phasically affected by cholinergic agents. The mean muscarinic inhibition of inspiration-related neurons increased with the progression of inspiration. The mean nicotinic inhibition of expiration-related neurons decreased with the progression of expiration. Results suggest that the efficacy of (i) a central inspiration terminating mechanism and (ii) the onset of discharge of expiratory neurons is modulated by acetylcholine.

Acetylcholine↗
PubMed1990

Effect of diaphragmatic respiration with end-tidal CO2 biofeedback on respiration, EEG, and seizure frequency in idiopathic epilepsy.

Breathing rate (RR), end-tidal percent CO2, and EEG were obtained in three groups: psychiatric referral subjects presenting with anxiety, panic phobia, depression and migraine; a group of idiopathic seizure sufferers; and a group of asymptomatic controls. Virtually all the noncontrol subjects were found to show moderate to severe hyperventilation and the accompanying EEG dysrhythmia. The seizure group subjects were taught diaphragmatic respiration with end-tidal percent CO2 biofeedback. The training normalized their respiration and altered their EEGs and seizure frequency.

Adolescent↗