Clinical significance of reflexes from the respiratory system.
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Humans↗
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Forced oscillation techniques for measuring mechanical properties of the respiratory system.
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Humans↗
[Experiments on blood aspiration in the lower respiratory system].
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Aspirations, Psychological↗
[Terramycin in the treatment of tuberculosis and suppurative diseases of the respiratory system].
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Oxytetracycline↗
Referencing lung volume for measurements of respiratory system compliance in infants.
We propose a method for measurements of respiratory system compliance (Crs) in spontaneously breathing infants, which circumvents the potential problems introduced by the breath-by-breath oscillations in the end-expiratory level, i.e., functional respiratory capacity (FRC). Changes in lung volume (V) and pressure at the airway opening (P(ao)) were measured in 10 infants breathing through a face mask. A first brief occlusion was to establish a reference V and the corresponding static P(ao); a second occlusion was done at a different V, within the same expiration, or in the following breath. Both occlusions were sufficiently long for the establishment of a stable P(ao) value. From the V difference (delta V, where delta V was at least 20% tidal volume) and the corresponding difference in P(ao) (delta P(ao)) Crs was computed and averaged (Crs[REF.VOL.] = delta V/delta P(ao). Although, on average, the results were similar to those obtained by the traditional multiple occlusions technique with linear regression analysis of the P(ao)-V data points (Crs[MOT]), in several infants Crs[REF.VOL.] tended to be slightly higher than Crs[MOT]. Some possibilities for this discrepancy are discussed. It seems likely that breath-to-breath oscillation in FRC may potentially lower Crs[MOT] by introducing a bias on the V measurement at low P(ao). We conclude that referencing V for Crs measurements in spontaneously breathing infants is a simple approach, which does not require linear regression analysis and circumvents the effects of oscillation in FRC.
Female↗
The impact of sugar cane-burning emissions on the respiratory system of children and the elderly.
We analyzed the influence of emissions from burning sugar cane on the respiratory system during almost 1 year in the city of Piracicaba in southeast Brazil. From April 1997 through March 1998, samples of inhalable particles were collected, separated into fine and coarse particulate mode, and analyzed for black carbon and tracer elements. At the same time, we examined daily records of children (<13 years of age) and elderly people (>64 years of age) admitted to the hospital because of respiratory diseases. Generalized linear models were adopted with natural cubic splines to control for season and linear terms to control for weather. Analyses were carried out for the entire period, as well as for burning and nonburning periods. Additional models were built using three factors obtained from factor analysis instead of particles or tracer elements. Increases of 10.2 microg/m3 in particles<or=2.5 microm/m3 aerodynamic diameter (PM2.5) and 42.9 microg/m3 in PM10 were associated with increases of 21.4% [95% confidence interval (CI), 4.3-38.5] and 31.03% (95% CI, 1.25-60.21) in child and elderly respiratory hospital admissions, respectively. When we compared periods, the effects during the burning period were much higher than the effects during nonburning period. Elements generated from sugar cane burning (factor 1) were those most associated with both child and elderly respiratory admissions. Our results show the adverse impact of sugar cane burning emissions on the health of the population, reinforcing the need for public efforts to reduce and eventually eliminate this source of air pollution.
Aged↗
Changes in the hepatic mitochondrial respiratory system in the transition from weaning to adulthood in rats.
In the present study we investigated the changes in the hepatic mitochondrial respiratory system in the transition from weaning to adulthood in the rat. We conceptually divided the system into blocks of reactions that produced or consumed mitochondrial membrane potential and then measured the kinetic responses of these blocks of reactions to changes in this potential in isolated liver mitochondria from 25- and 60-day-old rats using succinate as substrate. Moreover, we considered the mitochondrial membrane potential producers to be divided into blocks of reactions that reduced or oxidized ubiquinone-2 (Q-2) and then measured the kinetic responses of these two blocks to changes in Q-2 redox state as well as the flux control coefficients and the cytochrome content. We found that adult rats exhibited significantly higher state 3 respiratory rates with increased kinetic response of the substrate oxidation pathway to the mitochondrial membrane potential, slightly decreased activity of the phosphorylating system, increased kinetic responses of both Q-2 reducers and oxidizers to Q-2 redox state, and increased cytochrome content. Our results indicate that important changes in the hepatic mitochondrial respiratory system occur in the transition from weaning to adulthood in rats.
Age Factors↗
The effect of changing end-expiratory pressure on respiratory system mechanics in open- and closed-chest anesthetized, paralyzed patients.
The decrease in functional residual capacity (FRC) with anesthesia may cause lung volume to decrease below closing volume, thereby impairing oxygenation. Increasing end-expiratory pressure (EEP) reexpands atelectatic areas in anesthetized, ventilated patients, but its effect on pulmonary mechanics is less well understood. We studied the effect of varying EEP on the mechanical behavior of the respiratory system in patients undergoing either closed (Group 1) or open-chest (Group 2) surgical procedures. We measured airway opening pressure (PaO), flow (V), and esophageal pressure (Pes) (in Group 1 only) at EEPs of 0, 2.5, 5, and 10 cm H2O. Dynamic elastance (E) and resistance (R) for the respiratory system (RS), the lung (L), and the chest wall (CW) were estimated by fitting the equation P = RV + EV + K to the measured data by multiple linear regression where P was either Pao, Pes, or Pao-Pes. Group 1 EL decreased with increases in EEP to 5 cm H2O and then began to increase with EEP above this level. The same occurred in Group 2 before opening the chest. After opening the chest in Group 2, EL increased as EEP increased at all values above 0 cm H2O. The magnitudes of RRS and RL were similar in both groups of subjects and in each group these quantities decreased with increases in EEP. Dynamic EL responded differently to changes in EEP in subjects with open-chest and closed-chest procedures. We attribute this difference to overdistension of the remaining ventilable lung tissue at all levels of EEP in open-chest patients.
Adult↗
[Effects of clonidine on the cardiovascular and respiratory systems after cardiac surgery].
The aim of the study was to evaluate the effects of clonidine on the cardiovascular and respiratory systems after cardiac surgery. Ninety-six patients who had undergone scheduled myocardial revascularization were examined. According to the type of used anesthesia, the examinees were divided into 2 groups: 1) 60 patients who received standard anesthesia (a control group) and 2) 36 patients in whom the anesthesia was supplemented by clonidine. In Group 2, the total dose of the narcotic analgesic phentanyl was 14.15 +/- 6 microg/kg while in Group 1, the dose of opiod was 18.13 +/- 4.75 microg/kg (p < 0.05). Statistically significant minimum doses of catecholamines were more frequently used in Group 2 (27% versus 15% in the control group) (p < 0.05). The duration of artificial ventilation was 9.6 +/- 7.5 and 9.2 +/- 5.5 hours in Groups 1 and 2, respectively (p > 0.05). Positive fluid balance within the first 24 postoperative hours was 2324 +/- 1450 and 1587 +/- 1019 ml in Groups 1 and 2, respectively (p > 0.001).
Aged↗
Randomised controlled trial of respiratory system compliance measurements in mechanically ventilated neonates.
AIM: To determine whether outcomes of neonatal mechanical ventilation could be improved by regular pulmonary function testing. METHODS: Two hundred and forty five neonates, without immediately life threatening congenital malformations, were mechanically ventilated in the newborn period. Infants were randomly allocated to conventional clinical management (control group) or conventional management supplemented by regular measurements of static respiratory system compliance, using the single breath technique, with standardised management advice based on the results. RESULTS: Fifty five (45%) infants in each group experienced one or more adverse outcomes. The median (quartile) durations of ventilation and oxygen supplementation were 5 (2-12) and 6 (2-34) days for the control group, and 4 (2-9) and 6 (3-36) days for the experimental group (not significant). On post-hoc secondary analysis, control group survivors were ventilated for 1269 days with a median (quartile) of 5 (2-13) days, and experimental group survivors were ventilated for 775 days with a median (quartile) duration of 3 (2-8) days (p = 0.03). CONCLUSIONS: Although primary analysis did not show any substantial benefit associated with regular measurement of static respiratory system compliance, this may reflect a type II error, and a moderate benefit has not been excluded. Larger studies are required to establish the value of on-line monitoring techniques now available with neonatal ventilators.
Female↗
Helicobacter pylori infection as a possible risk factor for respiratory system disease: a review of the literature.
Helicobacter pylori (HP) infection may cause extradigestive manifestations directly or indirectly, by potential mechanisms. HP infection triggers a marked local inflammatory response and a chronic systemic immune response. Some of the mediators that are thought to be possibly involved in the pathogenesis of extradigestive diseases caused by HP infection include IL-1, TNF-alpha, interferon (IFN)-gamma, leukotriene C4 and platelet-activating factor. Previous epidemiological and serological case control studies have revealed that HP infection might have a role in the development of chronic bronchitis, bronchiectasis, lung cancer and tuberculosis. However HP infection does not appear to have a role in the development of bronchial asthma. Considering the importance and prevalence of respiratory system diseases, it may be time to conduct well-designed sets of studies to clarify whether there is an association with HP infection and respiratory system diseases, and to answer questions that have been posed regarding the patterns of histology, genotypes of HP, and the effects of eradication therapy. The aim of this review was to analyze the possible association between HP and respiratory disease and provide a critical review of the relevant literature.
Asthma↗
Respiratory system responsiveness in rabbits in vivo is reduced by prolonged continuous positive airway pressure.
Active, nonanesthetized, tracheotomized rabbits were subjected to continuous positive airway pressure (CPAP) for 4 days to determine the effects of chronic mechanical strain on lung and airway function. Rabbits were maintained for 4 days at a CPAP of 6 cmH(2)O (high CPAP), at a CPAP of 0 cmH(2)O (low CPAP), or without tracheostomy (no CPAP). After treatment with CPAP, changes in respiratory resistance in response to increasing concentrations of inhaled ACh were measured during mechanical ventilation to evaluate respiratory system responsiveness in vivo. Intraparenchymal bronchial segments were isolated from the lungs of all animals to evaluate airway smooth muscle responsiveness and bronchial compliance in vitro. Rabbits maintained for 4 days at high CPAP demonstrated significantly lower responsiveness to ACh compared with rabbits that were maintained at low CPAP or with no CPAP. Airways isolated from the lungs of animals subjected to the chronic application of high CPAP were also less responsive to ACh in vitro than the airways isolated from animals subjected to low CPAP or no CPAP. The persistence of the decreased responsiveness in the excised airway tissues suggests that the decreased respiratory system responsiveness observed in vivo results primarily from direct effects on the airways. The results demonstrate that the application of prolonged mechanical strain in vivo can reduce airway reactivity.
Acetylcholine↗
Functional and structural optimization of the respiratory system of the bat Tadarida brasiliensis (Chiroptera, Molossidae): does airway geometry matter?
We studied structure and function of the respiratory system in the bat Tadarida brasiliensis and compared it with those of two species of rodents, Abrothrix andinus and A. olivaceus. Tadarida brasiliensis had lower resting oxygen consumption, but higher maximum oxygen consumption and aerobic scope, than the rodents. The blood-gas barrier of the bat was thinner and its relative lung size was larger; however, alveolar surface density was similar among the three species. In consequence, T. brasiliensis has an oxygen diffusion capacity two or three times higher than that of the rodents. In Tadarida brasiliensis the characteristics of the lung were accompanied by geometrical changes in the proximal airway, such as high physical optimization as a consequence of small variations in the symmetry and the scaling ratio of the bronchial diameters. These may constitute an efficient way to save energy in respiratory mechanics and are the first report of airway adjustments to decrease entropy generation in bats.
Animals↗
Resolution of the aerobic respiratory system of the thermoacidophilic archaeon, Sulfolobus sp. strain 7. I. The archaeal terminal oxidase supercomplex is a functional fusion of respiratory complexes III and IV with no c-type cytochromes.
The aerobic respiratory system of the thermoacidophilic archaeon, Sulfolobus sp. strain 7, is unusual in that it consists of only a- and b-type cytochromes but no c-type cytochromes. In previous studies, a novel cytochrome oxidase a583-aa3 subcomplex has been purified, which showed a ferrocytochrome c oxidase but no caldariellaquinol oxidase activity (Wakagi, T., Yamauchi, T., Oshima, T., Müller, M., Azzi, A., and Sone, N. (1989) Biochem. Biophys. Res. Commun. 165, 1110-1114). We show here that the cytochrome subcomplex could be copurified with a non-CO-reactive cytochrome b562 as a novel terminal oxidase "supercomplex," which also contained a Rieske-type FeS cluster at gy = 1.89. It contained one copper and all four heme centers detectable in the archaeal membranes by the low temperature spectrophotometry and the potentiometric titration: cytochromes b562 (+146 mV), a583 (+270 mV), and aa3 (+117 and +325 mV). The presence of one copper atom indicates that it contains the conventional heme a3-CuB binuclear center for reducing molecular oxygen. In conjunction with the presence of a Rieske-type FeS center, inhibitor studies suggest that the terminal oxidase segment of the respiratory chain of Sulfolobus sp. strain 7 is a functional fusion of respiratory complexes III and IV, where cytochrome b562 and the Rieske-type FeS center probably play a central role in the oxidation of caldariellaquinol. This archaeal terminal oxidase supercomplex reconstitutes the in vitro succinate oxidase respiratory chain for the first time together with caldariellaquinone and the purified cognate succinate:caldariellaquinone oxidoreductase complex. The reconstitution system requires caldariellaquinone for the activity, and is highly sensitive to cyanide and 2-heptyl-4-hydroxy-quinoline-N-oxide. These results are also discussed in terms of the evolutionary considerations.
Cytochrome a Group↗
Dynamic respiratory system mechanics in infants during pressure and volume controlled ventilation.
Dynamic respiratory system mechanics can be determined using multiple linear regression (MLR) analysis. There is no need for a particular ventilator setting or for a special ventilatory manoeuvre. The purpose of this study was to investigate whether or not different ventilator modes and the flow-dependent resistance of the endotracheal tube (ETT) influence the determination of resistance and compliance by MLR. Ten paediatric patients who were on controlled mechanical ventilation for various disorders were investigated. The ventilator modes were changed between pressure control (PC) and volume control (VC). Flow and airway pressure were measured and tracheal pressure was continuously calculated. Each mode was applied for 3 min, and 10 consecutive breaths at the end of each period were analysed. Respiratory mechanics were determined by MLR based on either airway pressure, thus including the resistance of the ETT, or tracheal pressure. Resistance was found to be slightly higher in PC than in VC. There was no effect on determination of compliance between the different modes. Elimination of the flow-dependent resistance of the ETT preserved the differences between the modes. The authors conclude that using multiple linear regression compliance is not affected by the actual ventilator mode, whereas resistance is.
Airway Resistance↗
Contribution of large airway to the input impedance of the respiratory system.
To evaluate the contribution of the large airway to total respiratory impedance, we develop a one-dimensional model of pressure and flow in these airways by coupling conservation of mass and momentum equations with the geometric information obtained by the acoustic reflection technique. We use this model to calculate the impedance of the respiratory system distal to the carina from impedance data estimated at the airway opening by the forced oscillation technique. Simulations show that the real part of the impedance distal to the carina is uniformly decreased from the impedance at the airway opening, indicating a resistive loss, while the imaginary part is increased as a function of frequency. We estimate parameter values for a six-parameter two-compartment lung model and for a three-parameter reduction of this model before and after the application of the upper airway data to the impedance spectrum. Although compliance terms seem to be minimally affected by the manipulation of the data, resistance and inertance terms are influenced in a fashion that suggests that the resistive contribution of the upper airway to total respiratory impedance is significant. Furthermore it appears that the elastic nature of the walls of the upper airway also impact on estimates of total respiratory impedance at the airway opening.
Airway Resistance↗
Assessment of the respiratory system in workers occupationally exposed to phosphorite and apatite dusts.
The respiratory system in 118 male workers occupationally exposed to phosphorite and apatite dusts was assessed. Subjective, physical and spirographic examinations were performed and chest X-ray pictures were taken. No significant differences between the exposed workers and the control group were found. There was only a statistically significant decrease in spirometric parameters in the exposed group in comparison with controls. There was no such relationship in regard to the length of employment and smoking habit. In the exposed group there were no significant disturbances of the lung ventilation efficiency.
Adult↗
[The role of penicillins in the treatment of respiratory system infections].
The development of antimicrobial resistance in main pathogens of respiratory system infections (S. pneumoniae, H. Influenzae, B. catarrhalis) reduces the range of unprotected penicillins indications. The inhibitors of beta-lactamase rendered back the original spectrum of antimicrobial activity to aminopenicillins and ureidopenicillins, and withheld them within the most frequently used armamentarium of antimicrobial drugs for the therapy of more severe infections. The prescription of penicillins is ruled according to the localization of infection, most frequent pathogens and by the epidemiologic situation. A combined antibiotic therapy is indicated in severe infections. An important indication area is the prophylactic administration of penicillins in recurring tonsilopharyngitis, recurring otitis media and eradication of meningococcal carriership. (Tab. 1, Ref. 3.).
Humans↗