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PubMed1986

[Status of the cardiovascular and respiratory systems during immunosorption].

Blood was perfused through 2 series connected columns during immunosorption. The first column contained a mixture of immunosorbent and activated carbon, the second activated carbon only. In most patients the perfusion time was 40 min, and the volume of perfused blood 2000 ml. The procedure was performed under the conditions of operative control over the state of the cardiovascular and respiratory system using a monitor-computer system KOMPAS-01 in order to follow 5 hemodynamics values and 10 values of external respiration. A considerable effect of the procedure on the patients' hemodynamic patterns was revealed during hemosorption. These changes manifested themselves mainly in a decrease in stroke volume, cardiac output and changes in rate of the heart beat. External respiration values were more stable.

Adult↗
PubMed2003

Effects of childhood respiratory diseases on the anatomical and functional development of the respiratory system.

The anatomical and functional development of the lung appears especially vulnerable to a whole range of insults during gestation and the first few years of life. A significant proportion of adult lung disease originates in utero or early infancy. Most publications on this topic are descriptive retrospective studies. An important limitation of these is that structural changes may precede abnormalities in lung function and development of symptoms. Little is known with certainty with respect to the long-term effects of early insults to the respiratory system. Furthermore, the reversibility of the functional and/or structural defects is hardly ever adequately investigated and it is probably not correct to extrapolate findings from adult studies to paediatric pulmonary diseases. Promoting or facilitating optimal lung growth in fetuses and infants and reducing the incidence of lower respiratory tract infection in infancy may reduce the incidence of adult chronic lung disease in generations to come.

Child↗
PubMed1995

The respiratory system of Kluyveromyces lactis escapes from HAP2 control.

A functional homolog of the Saccharomyces cerevisiae HAP2 gene, coding for one element of a transcriptional activator complex, was cloned from the yeast Kluyveromyces lactis and its nucleotide sequence was determined. Inactivation of the gene had no significant effect on respiration-dependent growth, suggesting that the HAP2/3/4 complex has no major control over the formation of the mitochondrial respiratory system in K. lactis.

Amino Acid Sequence↗
PubMed1985

Effective resistance of the respiratory system studied by a quick release technique.

A human subject with mouthpiece in place makes inspiratory or expiratory effort against a closed shutter which abruptly opens when a predetermined pressure (PO) is developed. Pressure at the mouth (Pao) and flow (V) are continuously recorded. When the shutter opens, Pao changes toward atmospheric - first abruptly and then gradually, while V rapidly rises to a peak value (Vpeak) and then gradually declines. In any series of trials PO is held constant, but resistance external to the subject (Rext) is changed with each trial. In different series PO is varied. In any series of trials at constant PO the relationship between Pao and V was linear. The slope (K) of the straight line fitted to the experimental points was interpreted as being equal in magnitude to the 'effective resistance' (Reff) of the respiratory system. Reff has two components - a true resistance (Rint) and a virtual one (Rfv) related to the force-velocity characteristic of the respiratory muscles. On the assumption that Rint is independent of PO but that Rfv varies linearly with it, Rint and Rfv can be evaluated.

Airway Resistance↗
PubMedDate not supplied

[Changes in the respiratory system of patients with rheumatoid arthritis].

Rheumatoid changes in the lungs are seen in 30% of cases of rheumatoid arthritis. Three cases with different patterns of pulmonary involvement in the course of rheumatoid arthritis (RA) are presented. In all cases pleural involvement was seen, in two subjects since the beginning, in the remaining in the course of developing interstitial lung disease. In two cases the dominant changes in the respiratory system were interstitial pneumonitis. In one case the interstitial pneumonitis took a fulminating course, being resistant to treatment with prednisone, endoxan, penicillamine. In the third case, the interstitial pneumonitis was of chronic character, despite the fact that the subject did not receive any treatment, it did not progress. In the first case the main features were pulmonary cavities. The could have evolved from necrosis of rheumatoid nodules or vessel changes.

Adult↗
PubMed1997

[Effect of amrinone and vagotomy on airway constriction in dogs: analysis by respiratory system impedance method].

Amrinone, a selective phosphodiesterase III inhibitor, is a positive inotropic agent with vasodilating effect which is attributable to an increase in cyclic AMP in vascular smooth muscle. Little is known about the effect of amrinone on airway mechanics. The purpose of this study was to clarify the bronchodilating effect of amrinone in dogs, when bronchoconstriction was induced by methacholine infusion. We also evaluated the effect of amrinone on bronchoconstriction in vagotomized dogs. To evaluate the effect of amrinone on respiratory function, the total respiratory system impedance was measured using forced oscillation method by imposing a random noise. The analysis was performed by dynamic models and a second-order system curve fitting. From the study, we conclude that amrinone 0.5 mg.kg-1.1.0 mg.kg-1 or 2.0 mg.kg-1 attenuates methacholine-induced bronchoconstriction in a dose-related manner. In vagotomized dogs, amrinone also had the same effect on methacholine induced bronchoconstriction.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1997

Comparison of alveolar ventilation, oxygenation, pressure support, and respiratory system resistance in response to noninvasive versus conventional mechanical ventilation in foals.

OBJECTIVE: To compare the efficacy of positive pressure ventilation applied through a mask versus an endotracheal tube, using anesthetized/paralyzed foals as a model for foals with hypoventilation. ANIMALS: Six 1-month-old foals. PROCEDURE: A crossover design was used to compare the physiologic response of foals to 2 ventilatory techniques, noninvasive mask mechanical ventilation (NIMV) versus endotracheal mechanical ventilation (ETMV), during a single period of anesthesia and paralysis. Arterial pH, PaO2, PaCO2, oxygen saturation, end-tidal CO2 tension, airway pressures, total respiratory system resistance, resistance across the upper airways (proximal to the midtracheal region), and positive end-expiratory pressures (PEEP) were measured. Only tidal volume (VT; 10, 12.5, and 15 ml/kg of body weight) or PEEP (7 cm of H2O) varied. RESULTS: Compared with ETMV, use of NIMV at equivalent VT resulted in PaCO2 and pH values that were significantly higher, but PaO2 was only slightly lower. Between the 2 methods, peak airway pressure was similar, but peak expiratory flow was significantly lower and total respiratory resistance higher at each VT for NIMV. Delivery of PEEP (7 cm of H2O) was slightly better for ETMV (7.1 +/- 1.3 cm of H2O) than for NIMV (5.6 +/- 0.6 cm of H2O). CONCLUSION: These data suggest that use of NIMV induces similar physiologic effects as ETMV, but the nasal cavities and mask contribute greater dead space, manifesting in hypercapnia. Increasing the VT used on a per kilogram of body weight basis, or the use of pressure-cycled ventilation might reduce hypercapnia during NIMV. CLINICAL RELEVANCE: Use of NIMV might be applicable in selected foals, such as those with hypoventilation and minimal changes in lung compliance, during weaning from endotracheal mechanical ventilation, or for short-term ventilation in weak foals.

Aging↗
PubMed1989

A model of acoustic transmission in the respiratory system.

A theoretical model of sound transmission from within the respiratory tract to the chest wall due to the motion of the walls of the large airways was developed. The vocal tract, trachea, and the first five bronchial generations are represented over the frequency range from 100 to 600 Hz by an equivalent acoustic circuit. This circuit allows the estimation of the magnitude of airway wall motion in response to an acoustic perturbation at the mouth. The radiation of sound through the surrounding lung parenchyma is represented as a cylindrical wave in a homogeneous mixture of air bubbles in water. The effect of thermal losses associated with the polytropic compressions and expansions of these bubbles by the acoustic wave is included and the chest wall is represented as a massive boundary to the wave propagation. The model estimates the magnitude of acceleration over the extrathoracic trachea and at three locations on the posterior chest wall in the same vertical plane. The predicted spectral characteristics of transmission are consistent with previous experimental observations. This theoretical approach suggests that the locations of the spectral peaks are a strong function of the geometry and the wall properties of the airways, while the attenuation at higher frequencies is primarily associated with the absorption of sound in the parenchyma.

Animals↗
PubMed1995

Fatigue and the design of the respiratory system.

One source of muscle fatigue may be the failure to provide the required oxygen by any step in the oxygen transport cascade or a lack of the necessary machinery to utilize that oxygen. We favor abandoning the concept of a single rate-limiting step for the concept of tuned resistors, each contributing to the overall resistance to oxygen flow. However, because some of these steps have considerably less phenotypic plasticity than others, these are the component parts of the respiratory system that must be built with adequate "reserve" to accommodate adaptive increases in the other steps (Lindstedt et al., 1988; Weibel et al., 1992; Lindstedt et al., 1994). These structures will usually appear to be over built except in those rare individual animals at the species-specific limit of VO2 in which these less malleable structures may be limiting.

Animals↗
PubMed2004

Vertebrate lungs: structure, topography and mechanics. A comparative perspective of the progressive integration of respiratory system, locomotor apparatus and ontogenetic development.

Vertebrate lungs are highly diverse in their structure, topographical position, ventilation mechanisms, constructional integration into the locomotor apparatus, and the interrelationships with the mode of their ontogenetic development. Vertebrate lungs evolved as supplementary air-breathing organs in primary fishes, being ventilated by buccal pumping. In most recent fishes the lungs are transformed into the hydrostatic swimbladder. This basic type of unicameral lungs and their buccal pumping ventilation are also found in recent amphibians. Land vertebrates developed a very efficient aspiration type of ventilation. In most recent reptiles the lungs are subdivided into three rows of lung chambers, enlarging the exchange surface in correlation to their increasing metabolic needs. The avian respiratory apparatus, with its volume-constant lungs and highly compliant air sacs, and the mammalian broncho-alveolar lung, with its very low compliance, are both derived from multicameral lungs. The avian and the mammalian respiratory systems are integrated very differently with the specific constructions of their locomotor apparatusses and the specific mode of their ontogenetic development.

Animals↗
PubMedDate not supplied

[Aging of the respiratory system in various groups of the population].

Two groups of practically healthy elderly and old people were investigated. The first group consisted of 265 aborigens of three Abkhazian villages examined under field conditions, and the second group was composed of 227 inhabitants of Ukraine, the patients of clinic at Institute of Gerontology in Kiev. It was established that changes of the lung ventilation parameters typical of ageing were less pronounced in the Abkhazian inhabitants than in the Ukrainian ones. Ageing dynamics and values of the studied parameters were the same in Abkhazians: relatives of the long-living people and Abkhazians without hereditary predisposition to longevity. This fact permits a conclusion that the peculiarities of the respiratory system ageing in the Abkhazian population are mainly due to the environmental factors.

Adult↗
PubMed1988

Effects of unilateral pleural symphysis on respiratory system mechanics and gas exchange in anesthetized dogs.

Lateral thoracotomy with pleural abrasion and application of talc was performed on 8 adult beagle dogs. The dogs had no effusion detectable on roentgenogram at the time of study, and obliteration of the pleural space was later confirmed by autopsy. With the dogs under pentobarbital anesthesia, lung mechanics and gas exchange were studied before and 5 wk after surgery. Total lung capacity decreased to 78% of control value (p less than 0.05). After the operation, pressure-volume curves of the respiratory system were shifted down, along with significantly decreased compliance. Maximal flow at constant lung volume was not significantly increased. Arterial O2 and CO2 tensions were not significantly different. Rebreathing DLCO normalized for lung volume was unchanged. The slope of phase III of a single-breath nitrogen test was increased (p less than 0.05) after surgery. Unilateral surgical obliteration of the pleural space results in a pure restrictive pattern. It does not affect the gas exchange surface. The increase in the slope of phase III is suggestive of a nonhomogeneous distribution of ventilation.

Anesthesia↗
PubMed2000

Kinetics of respiratory system elastance after airway challenge in dogs.

We compared the time courses of lung mechanical changes with intravenous (iv) injection vs. aerosol administration of histamine, methacholine, and ACh in dogs. We interpret these results in terms of a spring-and-dashpot model of airway smooth muscle receiving activation via a tissue compartment when agonist is delivered by the iv route and through an additional airway wall compartment when it is delivered by the aerosol route. The model accurately accounts for the principal features of the respiratory system elastance response curves. It also accounts for the differences between iv and aerosol responses, supporting the notion that agonist delivered by aerosol has to traverse a longer pathway to the airway smooth muscle than does agonist delivered iv. The time constants representing diffusive exchange of agonist between compartments were not significantly different for the three agonists, suggesting that the three agonists shared a common principal means of clearance, which was presumably blood flow.

Acetylcholine↗
PubMed1977

Contribution of a Cyanide-insensitive Alternate Respiratory System to Increases in Formamide Hydro-lyase Activity and to Growth in Stemphylium loti in Vitro.

Stemphylium loti, a pathogen of a cyanogenic plant, possesses a cyanide-insensitive alternate respiratory pathway. In the absence of cytochrome inhibitors, the alternate system had only a minor role in respiration. When S. loti was grown in medium amended with antimycin to block the cytochrome chain, the alternate system accounted for the total oxygen consumption associated with respiration.The contribution of the alternate respiratory system to increases in formamide hydro-lyase (FHL) activity and to growth in S. loti in vitro was assessed. FHL, induced by cyanide, converts cyanide to nontoxic formamide and is partially responsible for the tolerance of S. loti to high concentrations of cyanide in vitro. When the cytochromes were blocked and the cyanide-insensitive respiratory pathway accounted for 100% of the oxygen uptake associated with respiration, FHL activity, but not changes in dry weight, was positively correlated with activity of the alternate pathway. As the alternate pathway activity decreased with increasing concentrations of salicylhydroxamic acid, the level of FHL activity correspondingly decreased. The alternate respiratory system may provide for increases in FHL activity but not for growth. S. loti appears to have two mechanisms for cyanide tolerance in vitro: cyanide-insensitive respiration and FHL activity. The initial activity of FHL for detoxification of cyanide may depend on the alternate respiratory pathway when the cytochromes of the electron transport chain are blocked.

Journal Article↗
PubMedDate not supplied

[The relation of the reactivity of the human respiratory system, mental and physical work capacity and metabolic characteristics during a 1-year stay in the mountains].

People with the highest rates of mental working capacity staying for a year at an altitude of 1680 m below sea level are characterized by less pronounced responses of respiration to moderate hypoxia and great ventilatory response to maximally endured hypoxic action, by higher glucose content in blood and physical working capacity. Many relationships typical of the middle mountains are inverse ones under conditions of a one-year stay at an altitude of 3650 m below sea level. In the case of a total decrease in indices of mental and physical working capacity people with the highest rate of information processing are characterized by less reactivity of the respiratory system, greater resistance to ultimate hypoxia, lower glucose concentration, less physical working capacity.

Adaptation, Physiological↗
PubMed2006

Right atrial size and function in patients with pulmonary hypertension associated with disorders of respiratory system or hypoxemia.

BACKGROUND AND AIM: Pulmonary hypertension (PH) determines various adaptive changes in right ventricular (RV) geometry which may progressively lead to hypertrophy, mechanical dysfunction and dilatation with pump failure. Right atrium (RA) is theoretically involved in this physiopathological process, but its role has never been investigated. We hypothesized that RA increases volume and function to assist RV during the chronic pressure overload exposition due to PH. METHODS: We prospectively enrolled 66 consecutive patients referred to our echolab with a diagnosis of PH [defined as pulmonary artery systolic pressure (PASP) >30 mmHg] associated with disorders of the respiratory system and/or hypoxemia and normal RV systolic function. Ejection force was taken up as index of RA systolic function and calculated according to the Manning's formula. Thirty-three healthy subjects for whom PH was definitely excluded by echoDoppler evaluation were used as controls. RESULTS: PASP was 42+/-10 and 20+/-8 mmHg in PH patients and controls, respectively; p=0.00001). In comparison with controls, PH patients exhibited higher RA volume (37+/-13 vs 32+/-13 ml, p=0.04) and RA ejection force (6.7+/-3.0 vs 3.5+/-1.8 Kdynes, p=0.00001). Both variables were positively related to PASP (r=0.23 and 0.48, p=0.02 and 0.00001, respectively). CONCLUSIONS: In patients with chronic PH, RA size and systolic function significantly increase and parallel signs of activation of the Frank-Starling mechanism in both right chambers. The magnitude of these phenomena is positively related to PASP levels.

Adaptation, Physiological↗