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PubMed1964

RESPIRATION OF BASIDIOSPORES OF SCHIZOPHYLLUM COMMUNE.

Niederpruem, Donald J. (Indiana University Medical Center, Indianapolis). Respiration of basidiospores of Schizophyllum commune. J. Bacteriol. 88:210-215. 1964.-The aerobic metabolism of basidiospores of the wood-rotting mushroom Schizophyllum commune was investigated by use of manometric techniques and specific respiratory poisons. Basal respiration was stimulated markedly by the uncoupling agent 2,4-dinitrophenol. This effect was pH-dependent and was sensitive to antimycin A. A positive periodic acid-Schiff reaction and a respiratory quotient (CO(2)/O(2)) of near unity pointed to carbohydrate as the endogenous substrate. Oxygen consumption was increased by sucrose, certain hexoses, d-xylose, acetate, and ethanol. Oxidative assimilation was evident with d-glucose and acetate. Glucose oxidation was inhibited by cyanide, azide, antimycin A, Atabrine, and phenylmercuric acetate. These data implicate cytochrome oxidase, b- and c-type cytochromes, flavoprotein, and essential sulfhydryl groups in basidiospore respiration.

2,4-Dinitrophenol↗
PubMed1977

Evaluation of a simple device for bacteriological sampling of respirator-generated aerosols.

The Aerotest sampler (Olympic Medical Corp., Seattle, Wash.) is designed to detect bacterial contamination of respirator-generated aerosols in a simple one-step process. The sampler was evaluated by controlled contamination of Bennett AP-5, PR-2, and MA-1 respirators with Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter. Bacteria present as viable 1.4 to 3.5-mum particles in each of 77 aerosols were quantitated by using the Andersen viable-particle sampler, and the results were compared with those of colonies obtained from 10-s or 15-cycle Aerotest samples. All aerosols containing counts greater than expected in hospital air were detected by the Aerotest method. Thirteen of 14 aerosols containing less than 20 bacteria/0.028 m3 showed fewer than 5 colonies, whereas all aerosols containing greater than 1,000 bacteria/0.028 m3 showed at least 40 colonies. Aerosols with intermediate counts fell in between. Under the conditions described here, the Aerotest sampler was able to discriminate between the low levels of bacteria commonly found in hospital air and the bacterial contamination associated with nosocomial pneumonia. The Aerotest sampler provides a practical method for surveillance sampling of respirator nebulizers.

Acinetobacter↗
PubMed1992

Pharmacological actions of "kyushin," a drug containing toad venom: cardiotonic and arrhythmogenic effects, and excitatory effect on respiration.

The cardiotonic and arrhythmogenic effects, and the excitatory effect on respiration of "Kyushin," a drug containing toad venom, were studied in comparison with those of digoxin. In anesthetized rabbits, the maximum rate of rise of left ventricular systolic pressure (max dP/dt) was measured as an index of cardiotonic effect, and the respiratory flow was measured as an index of respiratory function. Intraduodenal (i.d.) administration of 80 mg/kg "Kyushin" produced a cardiotonic effect and an excitatory effect on respiration, but i.d. administration of 16 mg/kg digoxin produced only a cardiotonic effect, and conversely inhibited respiration. In anesthetized open-chest guinea pigs, myocardial contractile force was measured as an index of cardiotonic effect and the arrhythmogenic effect was evaluated from the appearance of arrhythmic myocardial contraction. By i.d. administration of a 20% ethanol suspension or solution, "Kyushin" and digoxin showed a cardiotonic activity with doses higher than 40 mg/kg and 0.25 mg/kg, respectively. The arrhythmogenic doses of "Kyushin" and digoxin by i.d. administration were 2560 mg/kg and 2 mg/kg, respectively, suggesting that the safety margin of "Kyushin" is broader than that of digoxin.

Amphibian Venoms↗
PubMed2003

Cardiac MR imaging with external respirator: synchronizing cardiac and respiratory motion--feasibility study.

The feasibility of electrocardiography (ECG)-synchronized respiration with an external cuirass-type respirator in cardiac magnetic resonance (MR) imaging was evaluated. Cardiac MR imaging was performed in 10 nonsedated healthy volunteers with an ECG-triggered external respirator that was modified for use in the MR environment. Coronary MR angiograms and multiphase gradient-echo cine images were acquired with one respiratory cycle performed per cardiac cycle. The technique was feasible and in this group of volunteers resulted in equivalent image quality but shorter acquisition times than those of conventional free-breathing and breath-holding techniques.

Adult↗
PubMed2004

Heat shock regulates the respiration of cardiac H9c2 cells through upregulation of nitric oxide synthase.

Mild and nonlethal heat shock (i.e., hyperthermia) is known to protect the myocardium and cardiomyocytes against ischemic injury. In the present study, we have shown that heat shock regulates the respiration of cultured neonatal cardiomyocytes (cardiac H9c2 cells) through activation of nitric oxide synthase (NOS). The respiration of cultured cardiac H9c2 cells subjected to mild heat shock at 42 degrees C for 1 h was decreased compared with that of control. The O2 concentration at which the rate of O2 consumption is reduced to 50% was increased in heat-shocked cells, indicating a lowering of O2 affinity in the mitochondria. Western blot analyses showed a fourfold increase in the expression of heat shock protein (HSP) 90 and a twofold increase in endothelial NOS (eNOS) expression in the heat-shocked cells. Immunoblots of eNOS, inducible NOS (iNOS), and neuronal NOS (nNOS) in the immunoprecipitate of HSP90 of heat-shocked cells showed that there was a sevenfold increase in eNOS and no changes in iNOS and nNOS. Confocal microscopic analysis of cells stained with the NO-specific fluorescent dye 4,5-diaminofluorescein diacetate showed higher levels of NO production in the heat-shocked cells than in control cells. The results indicate that heat shock-induced HSP90 forms a complex with eNOS and activates it to increase NO concentration in the cardiac H9c2 cells. The generated NO competitively binds to the complexes of the respiratory chain of the mitochondria to downregulate O2 consumption in heat-shocked cells. On the basis of these results, we conclude that myocardial protection by hyperthermia occurs at least partly by the pathway of HSP90-mediated NO production, leading to subsequent attenuation of cellular respiration.

Animals↗
PubMed1979

Effects of training on postexercise limb muscle EMG synchronous to respiration.

Twenty university students (10 trained and 10 untrained) participated in 60 sessions testing the effect of training on postexercise electromyogram synchronous to respiration. The latter was recorded for m. biceps brachii dextra, m. quadriceps femoris dextra, and m. gastrocnemium dextra. The respiration rate was taken before and after three levels of functional effort performed on a bicycle ergometer. The first (2 X 30 s with a 20-s interval at 100 rpm and 245 W) and the second (5 X 1 min with a 30-s interval after each min, at 90 rpm and 200 W) were of speed-developing nature; the third (20 min at 60 rpm and 117 W with 1-min interval every 5 min) was to develop endurance. Our observations show that the greatest percentage of a synchronous-to-respiration muscle bioelectric activity can be observed after the first two types of effort. In the third type the percentage is smaller and the duration of the activity is shorter. On the other hand, the percentage of biopotential occurrence is greater for untrained persons, with a considerable longer disappearance time. The phenomenon can be used as a criterion in the athlete's functional diagnosis.

Action Potentials↗
PubMed1982

Effects of salicylate and 2,4-dinitrophenol on respiration and metabolism.

The respiratory and metabolic responses to intravenous administration of sodium salicylate (240 mg/kg0.75) and 2,4-dinitrophenol (5.7 mg/kg0.75), uncouplers of oxidative phosphorylation, were studied in anesthetized, paralyzed, vagotomized, and glomectomized cats. During the initial 10 min after administration of salicylate, metabolic rate (VCO2) increased 70% and did not increase further during the experiment. Respiration, on the other hand, increased progressively at the same rate over the entire 60-min course of the experiment. The total increase in respiration was greater than 300%. Thus neither the time course nor the magnitude of the metabolic and respiratory responses were related. Similar findings were also obtained following administration of 2,4-dinitrophenol. We conclude that these agents stimulate respiration by a mechanism other than one related to the ability to uncouple oxidative phosphorylation and cause an increase in whole-body metabolism.

2,4-Dinitrophenol↗
PubMed1986

Ventilation of a rat with a large-animal respirator.

Rats were effectively ventilated with 100% O2 mixed with room air utilizing a modified tracheostomy tube and a Bird Mark 7 respirator to maintain arterial blood gases within normal limits. A 3-cm segment of rubber pilot tubing was attached to a 15-mm respiratory connector and a 3-cm piece of polyethylene catheter tubing was fitted snugly into the other end. The catheter was inserted and secured into the trachea of 250- to 500-g Sprague-Dawley rats with the adaptor hose of the respirator fitted onto the 15-mm connector following tracheostomy. Manometer and inspiratory flow rate controls of the respirator were set to their minimum operating position. Appropriate rate control adjustments were made when necessary as determined by arterial blood gas measurements. By use of the above ventilation system, adequate arterial blood gases of anesthesized rats can be maintained for greater than 3 h.

Animals↗
PubMed1994

Assessment of frequency shifts in R-R interval variability and respiration with complex demodulation.

A complex demodulation (CDM) method for continuous assessment of frequency shifts and time-dependent changes in amplitude in the rhythmic components existing in predefined frequency bands was proposed and applied to the analysis of high-frequency (HF) and low-frequency (LF) components of the R-R interval and to the analysis of respiration via impedance spirogram. Simulation studies revealed that this CDM technique furnishes mathematical features well suited to the investigation of non-stationary R-R interval signals and can delineate time-dependent fluctuations in both amplitude and frequency, accurately differentiating between HF and LF components. Analysis of data during paced breathing at different respiratory frequencies revealed that the estimated frequency of the HF component and respiration faithfully reflected the frequency of paced breathing. Analysis of data during dynamic exercise with increasing workload (20 W/min) showed that the frequency of the HF component was elevated with exercise and that both HF and LF amplitudes were reduced progressively with advancing load. CDM-derived frequency and amplitude of respiration were highly correlated to direct breath-by-breath respiratory frequency and tidal volume measurements. We conclude that this method could provide a powerful means for continuously assessing time-dependent changes in both cardiovascular and respiratory variations.

Adult↗
PubMed1997

Vasomotor instability preceding tilt-induced syncope: does respiration play a role?

This study aimed to determine whether alterations in cardiovascular dynamics before syncope are related to changes in spontaneous respiration. Fifty-two healthy subjects underwent continuous heart rate (HR), arterial blood pressure (BP), and respiratory measurements during 10-min periods of spontaneous and paced breathing (0.25 Hz) in the supine and 60 degrees head-up tilt positions. Data were evaluated by power spectrum and transfer function analyses. During tilt, 27 subjects developed syncope or presyncope and 25 remained asymptomatic. Subjects with tilt-induced syncope had significantly greater increases in low-frequency (0.04-0. 15 Hz) systolic BP, diastolic BP, and HR power during tilt than the asymptomatic subjects (P </= 0.01). This difference was present during spontaneous but not paced breathing. However, average tidal volume, respiratory rate, minute ventilation, proportion of breaths below 0.15 Hz, and low-frequency respiratory power during tilt did not differ between syncopal and nonsyncopal subjects. Transfer magnitudes between low-frequency respiration and BP, and between BP and interbeat interval, were also similar between groups. Thus vasomotor instability before syncope is not related to alterations in respiration or the cardiovagal baroreflex but may reflect oscillating central sympathetic outflow to the vasculature.

Baroreflex↗
PubMed2005

Variable coupling between olfactory system activity and respiration in ketamine/xylazine anesthetized rats.

In this study, we have characterized slow and fast oscillations at several stages of olfactory processing under light and deep ketamine/xylazine anesthesia in the albino rat. While monitoring the animal's respiration, we also obtained field potentials from the olfactory bulb and piriform (olfactory) cortex and simultaneously recorded membrane potentials in piriform cortex pyramidal cells. Our results demonstrate that oscillations are generally found at higher frequencies under lighter and lower frequencies under deeper anesthesia. In previous studies of cerebral cortex, similar results in ketamine/xylazine anesthetized animals have been interpreted to correspond with the higher frequencies found during waking and lower frequencies found in the sleep state. Correlation and coherence analysis between data obtained in the bulb and cortex reveals a clear difference in coupling depending on the anesthetic state of the animal. Specifically, activity recorded in the whole system is highly correlated with respiration during deep anesthesia, whereas only the olfactory bulb, and not the cortex, is correlated with respiration during light anesthesia. These data suggest that global activity in the piriform cortex is actually more directly tied to peripheral slow respiratory input during slow wave than fast wave states and that the coupling between olfactory structures can be dynamically modulated by the level of anesthesia and therefore presumably by different brain states as well.

Analgesics↗
PubMed1994

Effects of posture on the coordination of respiration and swallowing.

1. Although a pause in respiration during swallowing is a feature common to all mammals, inhibition usually occurs during expiration in adult humans and during inspiration in most other species. We tested the hypothesis that this difference is due, at least in part, to the position of the body while feeding. 2. The coordination of respiration and swallowing was studied in adult human subjects in two body positions; upright, which is typically human, and on hands and knees, which is similar to the feeding posture of most other animal species. 3. Our major finding was that the respiratory phase in which swallowing occurred was significantly related to posture. Swallows tended to occur late in the expiratory phase while feeding upright, but during early expiration while on all fours. 4. We speculate that the phase of respiration in which swallowing occurs changes with posture to compensate for the alterations in the mechanical properties of the upper body.

Animals↗
PubMed1990

Electrophrenic respiration in patients with craniocervical trauma.

We implanted electrophrenic respiration (EPR) units in 15 apneic quadriplegic patients with brain stem or high cervical cord injury. 11 of the patients achieved full-time respiration with EPR and another 2 achieved half-time respiration. Despite the loss of patients due to unrelated problems, 7 now use EPR continuously, 1 for 18 years. The factors involved in the significant success rate with EPR are discussed from the point of view of a neurosurgeon.

Adolescent↗
PubMed1984

Coupling of external to internal respiration.

Oxygen is required to generate chemical energy (ATP) to allow muscle contraction. The amount of chemical energy required is directly proportional to the work rate performed. Early in exercise, the muscle creatine phosphate and oxygen stores, primarily in the form of oxymyoglobin and oxyhemoglobin (oxygen content of venous blood decreases), are used for energy. This allows time for cardiac output and ventilation to increase to satisfy the total O2 requirement. Steady-state time depends on the level of work relative to the anaerobic threshold (AT). For work rates below the AT, steady-state for VO2 is achieved by 3 min and by 4 min for VCO2 and VE. For work rates above the AT, steady-states are considerably delayed or not achieved. For purposes of description of the pattern of external respiration (gas exchange at the lungs), three phases are defined. Phase I is the initial increase in VO2 and VCO2 at the start of exercise, lasting approximately 15 s. Because the gas exchange ratio (R) typically doesn't change during Phase I, the initial increase in VO2 and VCO2 must be due primarily to an increase in pulmonary blood flow and proportional increase in ventilation (cardiodynamic phase). Phase II is the exponential-like increase in VO2 and VCO2, which follow Phase I and terminates in a steady-state or asymptotic value (Phase III). At moderate work, VO2 increases more rapidly than VCO2 during Phase II (CO2 stores increase). Therefore, R decreases before it increases to the steady-state. Below the AT, the rate of external respiration equals the rate of internal respiration during Phase III.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbon Dioxide↗
PubMed2005

Fluctuations in end-expiratory lung volume during Cheyne-Stokes respiration.

We hypothesized that patients with Cheyne-Stokes respiration exhibit periodic increases in end-expiratory lung volume, mediated by changes in breath components, postinspiratory inspiratory muscle activity, or both. Calibrated inductive plethysmography revealed that 12 of 12 patients with Cheyne-Stokes respiration experienced increases in end-expiratory volume during hyperpnea: maximum 412 +/- 112 (SE) ml (range 75-1,543 ml). Compared with quiet breathing, the breath with largest increase in end-expiratory volume had larger tidal volume (867 +/- 107 vs. 567 +/- 38 ml, p < 0.01) and shorter expiratory time (1.25 +/- 0.11 vs. 1.66 +/- 0.15 seconds, p < 0.05). During decrescendo, the breath with largest decrease in end-expiratory volume had smaller tidal volume (p < 0.01) and longer expiratory time (p < 0.01). Cross-correlation of time series revealed that end-expiratory volume was related to both breath components (p < 0.0001). Bipolar needle electrodes revealed that scalene muscle activity at end-expiration was 50.7 +/- 14.0% higher at highest increase in lung volume than during preceding apnea (p < 0.05). Time series for scalene activity and end-expiratory volume were cross-correlated (p < 0.008). Increase in tonic scalene activity at end-expiration, however, was equivalent during crescendo and decrescendo phases: 50.6 +/- 22.1 versus 42.0 +/- 12.9% (p = 0.48). In conclusion, patients with Cheyne-Stokes respiration exhibit fluctuations in end-expiratory lung volume, primarily because of alterations in tidal volume and expiratory time rather than postinspiratory inspiratory muscle activity.

Aged↗
PubMed1998

Recording from afferents in the intact recurrent laryngeal nerve during respiration and vocalization.

The goal of this study was to determine whether sensory fibers in an intact recurrent laryngeal nerve (RLN) are influenced by respiration or vocalization. Patterns of RLN afferent activity were examined during respiration and evoked vocalization by means of midbrain electrical stimulation in cats anesthetized with alpha-chloralose. Nerve bundles were dissected from an intact RLN, with motor function preserved. The bundles were cut and the laryngeal end was placed on floating bipolar electrodes. Fifteen right RLNs were examined. A total of 9 single and multiunit afferent fibers from 4 cats were isolated and examined during respiration. Four units, analyzed from 3 fibers, showed respiratory phase modulation. Eight units, analyzed from 4 fibers in 1 cat, were observed during vocalization and showed no vocalization phase modulation. The RLN afferents could contribute to reflex modulation of the respiratory cycle, but more extensive sampling would be necessary to preclude effects from vocalization.

Afferent Pathways↗
PubMed1977

Effect of respiration on cardiac motion determined by cineangiography. Implications concerning three-dimensional heart reconstruction using computer tomography.

Based on 39 cineangiographies in 23 patients performed during respiration with tracing of the cardiac chambers and the diaphragm, it has been found that the heart moves significantly with respiration, approximately half as much as the diaphragm during shallow or normal respiration. The cardiac respiratory motion indicates that gating of the respiratory cycle as well as the cardiac cycle is necessary in three-dimensional reconstruction of the heart using a large number of heart beats for recording.

Adult↗
PubMedDate not supplied

Ultrasonic assessment of abdominal venous return. I. Effect of cardiac action and respiration on mean velocity pattern, cross-sectional area and flow in the inferior vena cava and portal vein.

Duplex scanning, i.e. combined real time ultrasonography and pulsed Doppler velocity measurement, of the inferior vena cava and portal vein was performed in 85 patients subjected to routine left and right heart catheterization. Mean blood velocity and volume blood flow in the inferior vena cava were found to be pulsatile, reflecting both cardiac action and respiration. Different flow patterns could be related to various heart conditions. The cross-sectional area of the inferior vena cava was also pulsatile, the normal variation with respiration being partial collapse during inspiration and maximum distension at end expiration. In the majority of patients, portal vein flow showed variation with respiration only, maximum flow occurring during expiration. The flow patterns found in the two veins were well in accordance with previous invasive findings in animals. It is concluded that duplex scanning is a useful tool in the assessment of abdominal venous return.

Adult↗