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PubMed1998

Treatment of Cheyne-Stokes respiration with nasal oxygen and carbon dioxide.

Cheyne-Stokes respiration (CSR) is common in patients with congestive heart failure (CHF) and is associated with significant nocturnal O2 desaturation, arousals and sympathetic activation. Nocturnal O2 reduces CSR by only about 50%. More complete suppression of CSR may be achieved by adding CO2 to O2. This study therefore aimed to evaluate the effects of nocturnal O2 plus CO2 on CSR, sleep and sympathetic activation. Nine patients with CHF (age 59+/-5 yrs; left ventricular ejection fraction 17.8+/-1.2% (mean+/-SEM) were studied in a cross-over, single-blind, placebo-controlled trial. After an accommodation night the patients were randomly assigned to one night each of O2 plus CO2 as well as air applied by nasal prongs. Nocturnal O2 plus CO2 reduced the duration of CSR as percentage of total sleep time (48.0+/-10 versus 7.4+/-2.0%; p=0.008) and increased arterial oxygen saturation (Sa,O2) as well as mean transcutaneous carbon dioxide tension (Ptc,CO2) (5.2+/-0.3 kPa (39+/-2 mmHg) versus 5.7+/-0.3 kPa (43+/-2 mmHg) p=0.011). Sleep did not improve and arousals were not reduced. Plasma noradrenaline was higher on the treatment night (486+/-116 versus 669+/-163 ng x L(-1); p=0.035). In conclusion, nocturnal O2 plus CO2 improves Cheyne-Stokes respiration in patients with congestive heart failure but has adverse effects on the sequel of Cheyne-Stokes respiration, namely sympathetic activation.

Administration, Intranasal↗

PubMed2004

Effect of water depth and water velocity upon the surfacing frequency of the bimodally respiring freshwater turtle, Rheodytes leukops.

This study examines the effect of increasing water depth and water velocity upon the surfacing behaviour of the bimodally respiring turtle, Rheodytes leukops. Surfacing frequency was recorded for R. leukops at varying water depths (50, 100, 150 cm) and water velocities (5, 15, 30 cm s(-1)) during independent trials to provide an indirect cost-benefit analysis of aquatic versus pulmonary respiration. With increasing water velocity, R. leukops decreased its surfacing frequency twentyfold, thus suggesting a heightened reliance upon aquatic gas exchange. An elevated reliance upon aquatic respiration, which presumably translates into a decreased air-breathing frequency, may be metabolically more efficient for R. leukops compared to the expenditure (i.e. time and energy) associated with air-breathing within fast-flowing riffle zones. Additionally, R. leukops at higher water velocities preferentially selected low-velocity microhabitats, presumably to avoid the metabolic expenditure associated with high water flow. Alternatively, increasing water depth had no effect upon the surfacing frequency of R. leukops, suggesting little to no change in the respiratory partitioning of the species across treatment settings. Routinely long dives (>90 min) recorded for R. leukops indicate a high reliance upon aquatic O2 uptake regardless of water depth. Moreover, metabolic and temporal costs attributed to pulmonary gas exchange within a pool-like environment were likely minimal for R. leukops, irrespective of water depth.

Animals↗

PubMed1996

Oxygen-dependent-regulation of Ehrlich ascites tumor cell respiration by nitric oxide.

Effects of nitric oxide (NO) on oxygen uptake of Ehrlich ascites tumor cells (EATC) were examined in a study of the biological actions of NO on respiration and energy metabolism at the cellular level. Endogenous respiration of EATC was inhibited reversibly by NO in a dose dependent manner. Oxyhemoglobin, an NO trapping agent, restored the respiration promptly. The inhibitory action of NO also depended on oxygen-concentration, and the duration of suppression was prolonged remarkably at low oxygen tension. Similar inhibition was also observed in the presence of glucose. In this case, both lactate production and glucose consumption were promoted by NOC 18, an NO generating agent, and the activation was enhanced by lowering the oxygen-concentration. Furthermore, the membrane potential of EATC was depolarized transiently by adding NO, and the degree of depolarization was decreased in the presence of glucose. These results suggest that at physiologically low oxygen tension in ascites fluid, NO acts not only as a cytotoxic respiratory inhibitor but also as a regulatory factor in the energy metabolism of EATC.

Animals↗

PubMed2026

Effects of Intravenously Administered Plasma from Exercise-Trained Donors on Mitochondrial Respiration in a Rat Model of Alzheimer's Disease.

PURPOSE: Dysfunction of mitochondria is observed early in Alzheimer's disease (AD), possibly driving the pathogenesis of the disease. This study aims to assess whether plasma from exercise-trained donors can enhance mitochondrial function in a transgenic AD model and to gain insight into the proteomic profile of the donor plasma. METHODS: Male McGill-R-Thy1-APP rats (n = 3 per treatment group) were treated at either an early preplaque stage (2.2 months) or a later stage (5.2 months) with plasma from exercise-trained donors (ExPlas), sedentary donors (SedPlas), or saline. The rats received 14 transfusions over 6 wk. Mitochondrial respiration was assessed in cornu ammonis (CA), dentate gyrus (DG), gastrocnemius, and left ventricle using high-resolution respirometry. Proteomic analyses were performed in donor blood using mass spectrometry. RESULTS: In early-stage AD rats, ExPlas improved hippocampal mitochondrial respiration. Compared with saline, CA oxidative phosphorylation (OXPHOS) capacity for complex I increased by +30.8 pmol O2·s-1·mg-1 (P < 0.001) and CI+II by +37.8 pmol O2·s-1·mg-1 (P < 0.001). Compared with SedPlas, CA OXPHOS for CI increased by +16.9 pmol O2·s-1·mg-1 (P = 0.01) and CI+II by +23.8 pmol O2·s-1·mg-1 (P = 0.007). In DG, similar improvements were only seen compared with saline. In CA, but not DG, of later-stage rats, ExPlas produced smaller but significant increases in CI and CI+II OXPHOS compared with saline, but no significant differences compared with SedPlas. No changes were observed in muscle or heart. Proteomics revealed enrichment of complement and platelet-related pathways in ExPlas. CONCLUSIONS: This proof-of-concept study shows that exercise-trained donor plasma enhances hippocampal mitochondrial respiration in early-stage AD rats and, to a lesser extent, in later-stage AD rats. The proteomic profile of the exercise-trained donor plasma indicates a role of altered complement and platelet functions.

Animals↗

PubMed1986

Observations on the effects of vibration and noise on plasma ACTH and zinc levels, pregnancy and respiration rate in the guineapig.

The responses of female guineapigs to vibration and noise were examined with the use of an apparatus designed to simulate transport. Peak levels of plasma ACTH and zinc concentrations were attained after 4 min of exposure to vibration and 80-90 dB of noise. The respiration rate, normally around 90/min, was increased to 103/min when the animals were moved (while still in their cages) to the experimental area; it rose to 129/min when the apparatus was switched on to expose the animals to vibration and noise. Those left adjacent to the apparatus and exposed to noise alone elevated their respiration rates to 115/min. Respiration rates returned to normal within 2.5 h. There was no apparent effect on the maintenance of pregnancy, gestation length, litter size or post-partum growth of the young born to guineapigs exposed to this vibration and noise for a period of 1 h at mid-term.

Adrenocorticotropic Hormone↗

PubMed2005

Catechol inhibits FADH2-linked respiration in rat liver mitochondrial fraction.

PURPOSE: The aim of this work was to investigate the hypothesis that catechol inhibits FADH -linked basal respiration in mitochondria isolated from rat liver homogenates. Moreover, catechol ability to induce peroxidation of biomolecules in liver nuclear fractions was also studied. METHODS: Rat liver homogenates were incubated with 1mM 1,2-dihydroxybenzene (catechol) at pH 7.4 for up to 30 minutes. After that, mitochondrial fractions were isolated by differential centrifugation. Basal oxygen uptake was measured using a Clark-type electrode after the addition of 10 mM sodium succinate. Nuclear fractions were incubated in the presence of 1 mM catechol for 17 hours at room temperature and the peroxidation of biomolecules was investigated by the reaction with thiobarbituric acid, which was determined spectrophotometrically at 535 nm. RESULTS: Catechol induced a time-dependent partial inhibition of FADH -linked basal mitochondrial respiration, however this substance was unable to induce a direct peroxidation of biomolecules in hepatic nuclear fractions. CONCLUSION: Catechol produced an inhibition of basal respiration associated to FADH2 in isolated liver mitochondria that could lead to cytotoxicity, ROS generation and cell death.

Animals↗

PubMed1996

Development of photosynthesis and respiration measurement system using mass spectrometry.

A closed gas-exchange system was developed to measure gross photosynthesis and respiration discriminately and simultaneously. The system developed in this study included a high performance mass spectral analyzer for gas measurements. The gas-exchange system consisted of a 3L assimilation leaf chamber, a 1L flexible metallic bag, gas supply apparatus, and a lighting system. The lights were turned on and gas measurements were started after the initial 12CO2 concentration level was increased to 500 ppm. The 13CO2 gas was added to the chamber 10 min after the start of the light period. The lights were turned off 15 min after the addition of 13CO2. The 12CO2 and 13CO2 concentrations in the chamber during the light and dark periods were measured for pothos and maize leaves. The 13CO2 absorption rate by the leaves was larger than that for 12CO2 during the light period. It was assumed that the 13CO2 absorbed by photosynthesis was not evoluted by respiration during the first 25 min from the start of the light period. Based on this assumption, gross photosynthetic rate and respiration rate were estimated by calculating the difference in uptake rates of 12CO2 and 13CO2 during the light period.

Argon↗

PubMed1994

Behavioral and pharmacological modulation of respiration in rhesus monkeys.

Changes in respiration associated with schedule-controlled behavior were determined in seated rhesus monkeys prepared with a pressure-displacement head plethysmograph for monitoring ventilation continuously during behavioral experiments. Subjects were trained to press a lever under fixed-ratio 40 and fixed-interval 300-s schedules of stimulus termination. Episodic increases in ventilation were closely associated with periods of responding under both schedules. Recurring episodes of increased ventilation occurred during fixed-ratio responding, and were separated by brief 10-s timeouts during which ventilation decreased. Under the fixed-interval schedule, both ventilation and response rate typically increased as the 300-s interval elapsed. The effects of cocaine, caffeine, and two adenosine agonists, 5'-N-ethylcarboxamidadenosine (NECA) and 2-(carboxyethylphenylamino)adenosine-5'-carboxamide (CGS 21680), on behavior and respiration were determined using a cumulative-dosing procedure. Drug-induced suppression of behavior eliminated the episodic increases in ventilation during the performance components of both schedules. Schedule-related increases in ventilation were compared to those produced by elevated levels of CO2 in inspired air. Exposure to 4% CO2 mixed in air increased ventilation in all subjects, and the combined effects of CO2 exposure and schedule-controlled responding on respiration appeared to be additive. The results suggest that behavioral activities may increase ventilation through increased metabolic demand and increased CO2 production.

Adenosine↗

PubMed1989

Effects of endophyte-infected fescue and cimetidine on respiration rates, rectal temperatures and hepatic mixed function oxidase activity as measured by hepatic antipyrine metabolism in sheep.

The effects of endophyte-infected fescue (Kentucky 31) hay and cimetidine on respiration rates, rectal temperatures and hepatic antipyrine uptakes of three mature ewes were measured in 15 experiments. Hepatic antipyrine uptake was measured as an indirect indicator of hepatic mixed-function oxidase (MFO) activity. Five experiments on each ewe were conducted during consumption of endophyte-free (one exp/ewe, control), endophyte-infected (two exp/ewe, EIF) and endophyte-infected fescue hay plus cimetidine (800 mg/d i.v., two exp/ewe, EIFC). Respiration rates increased (P less than .05) 2.6-fold after 11 d on EIF from 26 to 68 and decreased (P less than .025) to 27 breaths/min after 4 d of cimetidine treatment. Rectal temperatures increased (P less than .05) 1.1 degrees C after 8 d on EIF. Cimetidine lowered temperatures to control levels by d 4. Endophyte-infected fescue hay increased (P less than .05) hepatic antipyrine uptake 70% after 11 d, but uptake was lowered to control levels by cimetidine by d 4. Increased respiration rates and rectal temperatures in animals consuming EIF seem to be related to increased MFO activity. Cimetidine reversed some of these effects.

Alkaloids↗

PubMed1977

Respiration audiometry.

Since 1971 an impedance-plethysmographic method was been used to record changes in the breathing pattern of 218 high-risk infants during acoustic stimulation. The results of this technique, known as respiration audiometry, show that acoustically induced changes in the breathing pattern can be used as a hearing test for very young children. The results fall into four categories: excellent readability (45%), good readability (32%), readable (15%), not readable (8%). Respiration audiometry makes it possible in most cases to ascertain a child's hearing level. The neonatal period and early infancy are the ages best suited for investigations with respiration audiometry. The reliability of this method was found to be good.

Acoustic Impedance Tests↗

PubMedDate not supplied

Infant respiration monitoring--evaluation of a simple home monitor.

A new, inexpensive commercial infant respiration monitor, the Baby-Sitter by Direct Diagnostics Ltd, has been evaluated and subjected to clinical trial. Dual respiration recordings were made from infants exhibiting apnoeic episodes to compare the new monitor with an acceptable reference monitor (Graesby Medical Model MR10). Both monitors are designed to detect respiration movement by means of pressure pulses produced in an air-filled sensor attached to the infant's abdomen. The new monitor is found to have unacceptable performance.

Apnea↗

PubMed1976

Neonatal respirator allowing simultaneous ventilation and suction.

A new type of respirator for newborns allowing tracheal suction and ventilation simultaneously is presented. Additional characteristics are: a partly disposable air supply system, no apparatus deadspace and with one exception no moving parts. The performance of the respirator under varied conditions of lung mechanics was tested using a pneumatic lung thorax analogue. The procedure of tracheal suction was simulated and the effect on tidal volume and alveolar pressure investigated. Triggervolume and response time were also determined. Analysis shows that the respirator has qualities of flow- and pressure preset ventilators. Tracheal suction during ventilation does not impair the delivery of tidal volume. In mechanical ventilation with PEEP the alveolar pressure remains positive throughout the respiratory cycle despite suction.

Humans↗

PubMed1999

[Importance of respiration for non-invasive assessment of cardiac autonomic control in patients with ischemic left ventricular dysfunction].

UNLABELLED: Respiratory rate is an important factor influencing heart rate variability (HRV), but is usually ignored in the studies in patients with ischaemic heart disease (IHD). This factor may significantly contribute to the changes in HRV in ischaemic left ventricular impairment. We examined 186 patients with IHD (46 females, 140 males), including 54 pts with left ventricular ejection fraction < 40% and 132 pts with preserved LVEF (> or = 40%). HRV was evaluated in supine and standing position from short-term ECG (512 beats, 1 kHz, 12 bit) in time- (mean RR interval--RRI, and standard deviation of RRI-SD-RR) and frequency-domain (FFT). Power spectral density of high and low frequency (HF 0.14-0.5 and LF 0.04-0.15 Hz) was estimated and expressed as log-values. The frequency of respiration (fResp, Hz) was defined as the frequency of maximum HF power. RESULTS: Patients with LVEF < 40% had shorter RRI in supine (879 + 157 vs 942 +/- 147 ms, p < 0.05), but similar in standing. FResp was greater both in supine (0.308 +/- 0.05 vs 0.274 +/- 0.047 Hz) and in standing (0.329 +/- 0.055 vs 0.274 +/- 0.047, all p < 0.001) in low, as compared to preserved LVEF. As expected, HRV parameters were more reduced in LVEF < 40%. The differences of raw values were as follows: SD-RR 29 +/- 16 vs 34 +/- 15 i 27 +/- 13 vs 31 +/- 12 ms, both p < 0.05, HF 3.21 +/- 0.36 vs 3.33 +/- 0.32, p < 0.05 and 3.19 +/- 0.32 vs 3.21 +/- 0.29 p > 0.1, LF 3.41 +/- 0.33 vs 31.49 +/- 0.30 and 3.52 +/- 0.30 vs 3.61 +/- 0.32, p < 0.05, ANOVA). The differences were observed despite adjustment for age, sex and RRI. When fResp was added as covariate they became not significant. CONCLUSION: Patients with left ventricular dysfunction had faster rate of respiration. This finding may explain, in part, reduced HRV in these patients. The rate of respiration should be taken into account for correct interpretation of HRV analysis.

Autonomic Nervous System↗

PubMed1999

[A plea for the foundation of a counseling center for people using artificial respiration and their relatives].

BACKGROUND AND AIMS: Since the 1980s the group of people surviving with the aid of artificial respiration has expanded. So far, however, no information centre for such persons exists in Germany. Likewise, peer counselling is not a widely accepted method of allocating responsibility to afflicted persons. The task of an information centre would be to provide peer counselors who would advise people on artificial respiration. PATIENTS AND METHODS: Interviews with subjects and their relatives regarding the various aspects of artificial respiration. CONCLUSION: The foundation of such a counselling centre is recommended on account of the present need for a national information exchange and contact centre.

Community Mental Health Services↗

PubMed1976

The influence of the internal compliance of a respirator on the alveolar gas distribution.

The occurrence of intrapulmonary redistribution "pendelluft" during the plateau phase of a respirator, with and without internal compliance, was studied in a lung-model which simulated an obstructive inhomogeneity. Internal compliance was achieved by adding a flask, with a variable volume, to the patient circuit of a respirator which had a low compressible volume (Engström Care System ECS 2000, Junger Instrument AB, Sweden). The amount of redistributed volume was found to be dependent upon the internal compliance. Without additional compressible volume, the ventilator produced up to 18% redistribution which under all conditions could be brought below the 1% level when an internal compliance was introduced. A highly significant correlation between the amount of redistributed volume (pendelluft) and the discharge time-constant of the plateau (taupl = CI (RI + Rtr) could be established. The results of mathematical consideration gained from an electrical analogue coincided with our experimental findings. From this, some consequences could be derived for the design of an internal compliance for use with a respirator.

Airway Obstruction↗

PubMed2000

Impact of short-time nasal intubation on postoperative respiration.

Until now few data on postoperative nasal respiration after nasal intubation is known which is of special importance for surgery, where postoperative intermaxillary fixation is necessary. This study was planned to acquire information about nasal breathing during the first postoperative week. Twelve patients treated for mandibular retrognathism were examined repeatedly by way of anterior active rhinometry, acoustic rhinometry, and rhinoresistometry before and after surgery over one week. In addition the subjective evaluation was checked on a visual analogue scale. Following intubation, significant changes in "objective" and subjective measurements of nasal respiration could be noted only on the second postoperative day. Comparing rhinomanometric and subjective data, a correlation could be found on postoperative day two only. In this study group short-time nasal intubation had no significant impact on postoperative respiration.

Adult↗

PubMedDate not supplied

[Dynamics of the intensity of respiration in early embryogenesis of amphibians].

We studied growth and respiration rate during early ontogenesis of the axolotl Ambystoma mexicanum, Bosca's newt Triturus waltlii, the green toad Bufo viridis, and the smooth clawed frog Xenopus laevis. The respiration rate in these amphibian species increases during embryonal and larval development, peaks after transition to active feeding, and decreases at later stages of ontogenesis. The patterns of dynamics of this energy metabolism index in tailed and tailless amphibians have some differences related to their specific development. The changes in respiration rate in the embryos and larvae are correlated with the concentrations of mitochondria.

Amphibians↗

PubMed2000

[A case of amyotrophic lateral sclerosis presenting with circulatory collapse during artificial respiration].

A 71-year-old man developed dysarthria and difficulty of swallowing in December 1997. He was diagnosed as having the bulbar type of amyotrophic lateral sclerosis (ALS). In November 1998, he was admitted to our hospital to undergo treatment for bulbar palsy and respiratory discomfort. In January 1999, ventilatory support (synchronous intermittent mandatory ventilation) during sleep at night was initiated. Severe progressive hypotension and loss of consciousness were observed soon after the start of artificial respiration, and both symptoms disappeared after artificial respiration was discontinued. This phenomenon was observed consistently during ventilatory support, while unpleasant stimuli such as bronchoscopy and replacement of the cannula tube induced severe hypertension. To clarify the mechanism of underlying these abnormal changes in blood pressure, autonomic function tests were performed while awake during the daytime. Ventilatory support induced a drop in blood pressure accompanied by a decrease in influx speed to the right ventriculum, the latter of which suggested a reduction in venous return. These values returned to the baseline following detachment of the ventilator. A 60 degrees head-up tilt (HUT) angle and standing from a supine position produced orthostatic hypotension, the latter of which was accompanied by a compensatory increase in pulse rate. The basal supine plasma noradrenaline (NA) level was high and the HUT showed a slight elevation of NA. The basal supine plasma arginine vasopressin (AVP) level was within the normal range, whereas the AVP level did not increase during HUT. Urinary secretion rates of NA and 3-methoxy-4-hydroxy-phenylglycol were elevated. A cold pressor test demonstrated reflex hypertension. The oculovagal reflex, coefficient of variation of R-R intervals. (CVR-R) and increase in pulse rate in response to atropine administration were within the normal range. The combination of midodrine, L-dihydroxyphenylserine (DOPS) and increasing intravascular volume via continuous intravenous drip infusion relieved the circulatory collapse during artificial respiration. In conclusion, the present case of ALS had sympathetic hyperactivity, somatosympathetic reflex and dysregulation of the baroreflex arc. Degeneration of central autonomic network, including the hypothalamus and the central nucleus of the amygdala, which has been shown in some ALS patients, might underlie the autonomic abnormalities in this patient.

Aged↗