[On the value of a pharmacological test (adrenalin-pendiomide) in the examination of the circulation in some chronic diseases of the respiratory system].
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Bis-Trimethylammonium Compounds↗
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Results for “RESPIRATORY SYSTEM”
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Respiratory system of vegetative and sporulating Bacillus cereus.
The composition and organization of the Bacillus cereus respiratory system were studied. The abolition of NADH-dependent respiration in vegetative and sporulating cell membranes by near-UV light (360 nm) indicated that electrons reduce oxygen only through a quinone-cytochrome pathway. Difference spectroscopy demonstrated the presence of cytochromes b555, c548, aa3, b562, and a2. This composition and studies with respiratory inhibitors suggested that cytochromes are organized in at least two branches, one being highly sensitive to cyanide.
Bacillus cereus↗
Effect of oxidant air pollutants on the respiratory system: insights from experimental animal research.
In the present paper, we have reviewed experimental animal studies on the effects of the two most important oxidant airborne pollutants, nitrogen dioxide and ozone, on the respiratory system. The toxic effects depend on concentration and length of exposure, and are generally similar for both oxidants, with ozone operative at lower concentrations. High doses of both oxidants cause death due to lung oedema. Exposure to sublethal levels causes functional alterations such as airflow limitation and airway hyperresponsiveness to bronchoconstrictor stimuli. These effects, which are generally reversible, are associated with epithelial injury, oedema and airway and parenchymal infiltration by inflammatory cells. Loss of cilia of airway epithelium and necrosis of type I alveolar epithelial cells are the most prominent consequences at the epithelial level. Inflammation is characterized by early neutrophilic infiltration, followed by an increased number of mononuclear cells, predominantly alveolar macrophages. After long-term exposure, whilst nitrogen dioxide causes predominantly emphysema, ozone produces mainly pulmonary fibrosis. Biochemical effects include lipid peroxidation, increased antioxidant metabolism, and alteration of enzyme activity. Nitrogen dioxide and ozone may also alter the immunological response and reduce the defence against infections, increasing the susceptibility of exposed animals to infections.
Animals↗
A simple method of measuring total respiratory system compliance in newborn infants.
A new method of measuring the static compliance of the respiratory system in the awake, non-paralysed infant is described. The static compliance was measured by this method in 12 healthy premature infants aged from 1 day to 30 weeks. In addition, the dynamic compliance was measured by the oesophageal balloon technique. The static compliance was significantly higher than the dynamic, and this difference was related to the respiratory rate. These infants therefore demonstrated frequency dependence of dynamic compliance.
Compliance↗
[Deposition of particles in the respiratory system].
Aerosols consist of two phases: a gas phase and particle phase, either liquid or solid. Mathematical modeling of the three principal processes (impaction, sedimentation and diffusion) which determine the amounts of deposition of particles at various levels of the respiratory system is in agreement with the majority of experimental data, the upper airways behaving as a very effective filter for particles with an aerodynamic diameter greater than 2 micron. Below such a diameter, particles are capable of being deposited at all levels along the tracheo-bronchial system or in the terminal respirator units. This scale of micronic aerodynamic diameters furthermore corresponds to atmospheric aerosols with a long duration (monodispersed aerosols). Such findings have obvious consequences both in terms of the physiopathology of respiratory disorders as well as the therapeutic or diagnostic use of aerosols. In order to better define the deposition of infra-micronic particles, we used the Liu and Whitby analyser for measurement of particle concentration for diameters of between 0.0042 micron and 0.75 micron. The aerosol inhaled was ordinary atmospheric air with a stable profile. The respiratory tract of the subject was free of any particles after 5 respiratory cycles through a filter. Overall, expired particle concentrations decreased exponentially with the increase in apnea at the end of inspiration. This decrease was all the more marked when pulmonary capacity was smaller. These findings were apparently related to the increased probability of deposition by diffusion as the dimension of the air spaces decreases.
Aerosols↗
Lysyl oxidase is essential for normal development and function of the respiratory system and for the integrity of elastic and collagen fibers in various tissues.
Lysyl oxidases, a family comprising LOX and four LOX-like enzymes, catalyze crosslinking of elastin and collagens. Mouse Lox was recently shown to be crucial for development of the cardiovascular system because null mice died perinatally of aortic aneurysms and cardiovascular dysfunction. We show here that Lox is also essential for development of the respiratory system and the integrity of elastic and collagen fibers in the lungs and skin. The lungs of E18.5 Lox(-/-) embryos showed impaired development of the distal and proximal airways. Elastic fibers in E18.5 Lox(-/-) lungs were markedly less intensely stained and more disperse than in the wild type, especially in the mesenchyme surrounding the distal airways, bronchioles, bronchi, and trachea, and were fragmented in pulmonary arterial walls. The organization of individual collagen fibers into tight bundles was likewise abnormal. Similar elastic and collagen fiber abnormalities were seen in the skin. Lysyl oxidase activity in cultured Lox(-/-) skin fibroblasts and aortic smooth muscle cells was reduced by approximately 80%, indicating that Lox is the main isoenzyme in these cells. LOX abnormalities may thus be critical for the pathogenesis of several common diseases, including pulmonary, skin, and cardiovascular disorders.
Animals↗
GABAB receptor mediated effects on central respiratory system and their antagonism by phaclofen.
The role of GABAB receptors in control of central respiratory system was evaluated by cycle-triggered averaging of phrenic nerve activity (PNA) of the rabbit. Blockade of GABAB receptors of the caudal brainstem by intracerebroventricular administration of phaclofen augmented PNA, decreased the duration of inspiration and to about the same extent increased the duration of expiration thus unmasking intrinsically active GABA. Analogously, stimulation of brainstem GABAB receptors by exogenous baclofen decreased PNA. Preceding administration of larger doses of phaclofen could block the effects of baclofen. It is proposed that GABAB receptors are involved in tonic and phasic modulation of central respiratory activity.
Animals↗
The effects of positive end-expiratory pressure on respiratory system mechanics and hemodynamics in postoperative cardiac surgery patients.
We prospectively evaluated the effects of positive end-expiratory pressure (PEEP) on the respiratory mechanical properties and hemodynamics of 10 postoperative adult cardiac patients undergoing mechanical ventilation while still anesthetized and paralyzed. The respiratory mechanics was evaluated by the inflation inspiratory occlusion method and hemodynamics by conventional methods. Each patient was randomized to a different level of PEEP (5, 10 and 15 cmH2O), while zero end-expiratory pressure (ZEEP) was established as control. PEEP of 15-min duration was applied at 20-min intervals. The frequency dependence of resistance and the viscoelastic properties and elastance of the respiratory system were evaluated together with hemodynamic and respiratory indexes. We observed a significant decrease in total airway resistance (13.12 +/- 0.79 cmH2O l-1 s-1 at ZEEP, 11.94 +/- 0.55 cmH2O l-1 s-1 (P<0.0197) at 5 cmH2O of PEEP, 11.42 +/- 0.71 cmH2O l-1 s-1 (P<0.0255) at 10 cmH2O of PEEP, and 10.32 +/- 0.57 cmH2O l-1 s-1 (P<0.0002) at 15 cmH2O of PEEP). The elastance (Ers; cmH2O/l) was not significantly modified by PEEP from zero (23.49 +/- 1.21) to 5 cmH2O (21.89 +/- 0.70). However, a significant decrease (P<0.0003) at 10 cmH2O PEEP (18.86 +/- 1.13), as well as (P<0.0001) at 15 cmH2O (18.41 +/- 0.82) was observed after PEEP application. Volume dependence of viscoelastic properties showed a slight but not significant tendency to increase with PEEP. The significant decreases in cardiac index (l min-1 m-2) due to PEEP increments (3.90 +/- 0.22 at ZEEP, 3.43 +/- 0.17 (P<0. 0260) at 5 cmH2O of PEEP, 3.31 +/- 0.22 (P<0.0260) at 10 cmH2O of PEEP, and 3.10 +/- 0.22 (P<0.0113) at 15 cmH2O of PEEP) were compensated for by an increase in arterial oxygen content owing to shunt fraction reduction (%) from 22.26 +/- 2.28 at ZEEP to 11.66 +/- 1.24 at PEEP of 15 cmH2O (P<0.0007). We conclude that increments in PEEP resulted in a reduction of both airway resistance and respiratory elastance. These results could reflect improvement in respiratory mechanics. However, due to possible hemodynamic instability, PEEP should be carefully applied to postoperative cardiac patients.
Adult↗
Comparative respiratory system mechanics in rodents.
Because of the wide utilization of rodents as animal models in respiratory research and the limited data on measurements of respiratory input impedance (Zrs) in small animals, we measured Zrs between 0.25 and 9.125 Hz at different levels (0-7 hPa) of positive end-expiratory pressure (PEEP) in mice, rats, guinea pigs, and rabbits using a computer-controlled small-animal ventilator (Schuessler TF and Bates JHT, IEEE Trans Biomed Eng 42: 860-866, 1995). Zrs was fitted with a model, including a Newtonian resistance (R) and inertance in series with a constant-phase tissue compartment characterized by tissue damping (Gti) and elastance (Hti) parameters. Inertance was negligible in all cases. R, Gti, and Hti were normalized to body weight, yielding normalized R, Gti, and Hti (NHti), respectively. Normalized R tended to decrease slightly with PEEP and increased with animal size. Normalized Gti had a minimal dependence on PEEP. NHti decreased with increasing PEEP, reaching a minimum at approximately 5 hPa in all species except mice. NHti was also higher in mice and rabbits compared with guinea pigs and rats at low PEEPs, which we conclude is probably due to a relatively smaller air space volume in mice and rabbits. Our data also suggest that smaller rodents have proportionately wider airways than do larger animals. We conclude that a detailed, comparative study of respiratory system mechanics shows some evidence of structural differences among the lungs of various species but that, in general, rodent lungs obey scaling laws similar to those described in other species.
Airway Resistance↗
The influence of acute poisoning with an organophosphate compound on the regulation of breathing and the respiratory system efficiency.
The female patient, aged 40, was admitted to the Department of Toxicology about fifteen hours after she had drunk 50 ml Basudin 25 EC (diazinon contents 25%) in a suicidal attempt. On admission the patients state was described as moderately severe (9 points). Starting with the first day after the poisoning, the functional state of the respiratory system was monitored. Ventilation efficiency was determined on the basis of the results from a flow-volume curve, spirometry and the measurements of the respiratory tract resistance (Rrs) in a computerised system Lungtest-MES company (Poland). Respiratory regulation was evaluated by means of synchronic measurements of the respiratory pattern and occlusion pressure. The results obtained from a respiratory pattern and P 0.1 were refereed to normal values. In the examination carried out directly after the poisoning slight obturation of the central bronchi and elevation in resistance of respiratory tract was noted. After a week, obturation was not noted and the resistance value was better. Also the respiratory pattern parameters and value of occlusion pressure were better. It seems that in this case the increase in resistance values in the respiratory tract should be related to the increased activity in the parasympathetic system. Basic, traditional spirometric even in the examination on the first day after the poisoning, were within normal limits, while the parameters of respiratory pattern, occlusion pressure and respiratory resistance were beyond the norm. The results obtained from the measurements of respiratory pattern parameters correlated well with the clinical condition of the patient and with the results of biochemical and enzymatic measurements.
Adult↗
Reflex relationships between the cervical esophagus and the respiratory system in cats.
The present study focused on reflex relationships between the esophagus and the respiratory system in cats, namely the changes in airway tone and pulmonary circulation elicited by mechanical or acid (pH 2) stimulation of esophageal afferents. One-minute of sustained distension of the cervical esophagus increased tracheal pressure (PTr), decreased pulmonary artery pressure (PPA) and to a higher extent pulmonary blood flow (QPA) and lowered arterial blood pressure (Pa). This was associated with significant variations in arterial blood gases (increased PaO2 and decreased PaCO2). Acid stimulation of the cervical esophagus caused a marked increase in PTr and a modest fall in QPA. In both circumstances, cervical bivagotomy abolished PTr changes, whereas the changes in pulmonary hemodynamics but not in Pa were then accentuated. Further cervical sympathectomy suppressed the vascular response. These observations show the existence of reflex influences of esophageal afferents on the control of airway tone and pulmonary vascular resistance. The vagus nerve is the efferent arm of the bronchomotor reflex whereas modulation of the sympathetic control of pulmonary circulation seems to be responsible for the changes in pulmonary hemodynamics.
Animals↗
Transfer impedance of the respiratory system by forced oscillation technique and optoelectronic plethysmography.
To estimate the transfer impedance of the respiratory system (Ztr), we applied pressure forcing at the mouth from 1 to 24 Hz in eight healthy subjects and used optoelectronic plethysmography (OEP) to measure volume changes of the chest wall and its different compartments: pulmonary rib cage (RCp), abdominal rib cage (RCa) and abdomen (AB). Spectral analysis allowed assessment of input impedance (Zin) and total (Ztr) and compartmental (ZRCP, ZRCa, and ZAB) transfer impedances. As expected, averaged values of Zin and Ztr were similar at low frequencies (< 8 Hz) while they progressively differed at high frequencies. The percentage contributions of ZRCp, ZRCa , and ZAB to Ztr were, respectively, 35.3 +/- 1.4SD, 13.8 +/- 1.4, and 50.8 +/- 2.8 at low frequencies (< 8 Hz) and 63.1 +/- 5.5, 20.7 +/- 5.2, and 16.2 +/- 2.3 at higher frequencies (> 10 Hz). The validation of our approach was based on the comparison with a physical model comprised of a rubber membrane stretched over and attached to the lip of a bowl. We conclude that the combination of forced oscillations with OEP provides the simultaneous assessment of Zin and Ztr, it does not require the use of a plethysmographic chamber and it allows the separation between the different rib cage-abdominal pathways.
Abdomen↗
[Effects of toxic gases and phagocytic defense of the respiratory system. "In vitro" approach].
A new technique of cell culture in gas phase may be used for the "in vitro" study of the effects of toxic gases on the alveolar macrophages responsible for phagocytic defence of the respiratory system. Macrophage cells deposited on a porous membrane applied to the surface of a reservoir filled with nutrient fluid, survive in direct contact with the atmosphere, retaining normal metabolic and functional activities for several days. It is then possible to analyse the effects exerted on these cells by various types of gaseous aerocontaminants. This "in vitro" technique is highly sensitive. Nitrogen dioxide and ozone have cytotoxic effects after 30 minutes exposure at concentrations at less than 1 p.p.m. Acrolein has a harmful effect only at concentrations of 8 to 35 p.p.m. A mixture of oxygen (95 p. cent) and of CO2 (5 p. cent) causes much slower cell destruction, in a period varying from 2 to 6 days. Information provided by this method must be interpreted taking two concepts into account: 1--"in vitro" cytotoxicity explores only one aspect of the harmfulness of a gas, since the latter may have pathological effects by other mechanisms: irritant action on the respiratory mucosa resulting in hypersecretion and bronchospasm, ciliary paralysis or destruction, changes in the alveolar wall also capable of disturbing the phagocytic intervention of alveolar macrophages; 2--"in vitro", certain gaseous aerocontaminants are fixed or neutralised in part in the upper airway or by secretions lining the respiratory mucosa. In addition, the constant supply of new cells from the interstitium or pulmonary capillaries, limits the consequence of any possible destruction of phagocytic cells exposed to toxic gases. However, these reservations are compensated by the new possibilities offered by the "in vitro" study of the cytotoxicity of gases in the following areas: establishment of a hierarchy of gaseous pollutants, evaluation of their mechanism of action and determination of methods of protection against their harmful effects.
Acrolein↗
Effects of phrenic nerve section on the respiratory system of fetal lambs.
We investigated the effects of phrenic nerve section (PNS) on the respiratory system of fetal lambs. Seven ewes, three of which had twin fetuses, were given a general anesthetic. The thoracic phrenic nerves were cut in two singleton fetuses and in one fetus in each set of twins (116-121 days); two singleton fetuses and one fetus in each set of twins underwent the same procedure except for PNS. Fetal arterial blood pressure, heart rate, and arterial pH and blood gas tensions were the same in both groups. Phrenic nerve section eliminated fetal breathing movements and decreased airway fluid volume, lung weight, and total lung DNA (P less than 0.05). However, PNS did not affect production of tracheal fluid or percent dry weight of the lungs. Furthermore, PNS did not affect the concentration of saturated phosphatidylcholine in the lung or its flux in tracheal fluid. We conclude that PNS in fetal lambs retards lung growth but does not affect tracheal fluid production or formation and release of surfactant.
Animals↗
Immunity to mycoplasma infections of the respiratory system in the domestic fowl and turkey.
The mycoplasma infecting and sometimes causing disease of the respiratory system in both species are M. gallisepticum and M. synoviae, while M. meleagridis affects the turkey only. M. gallisepticum has received the greatest attention and natural infection is reported to result in protection varying greatly in degree and duration. Vaccination with living organisms either by the respiratory or intravenous routes results in a high degree of protection against air sac challenge for at least a few weeks. Killed organisms administered intravenously result in a lesser degree of protection to this challenge but when given intranasally provide no protection. M. gallisepticum survives in the respiratory tract and perhaps in other organs and tissues for long periods after infection, perhaps in latent form. However, intercurrent infection and other avian respiratory pathogens may precipitate multiplication of the organism and disease in birds apparently resistant to challenge with mycoplasma alone. The mechanism of protection has not been extensively studied and production and significance of local antibody or a cell-mediated response have not been determined. However, bursectomized chickens vaccinated against M. gallisepticum show much less resistance compared with controls but the exact part played by humoral antibody is still in doubt. Similar observations have been made with M. synoviae.
Agglutination Tests↗
Xanthoma disseminatum: a child with respiratory system involvement and bronchiectasis.
Xanthoma disseminatum (XD) is a rare normolipemic mucocutaneous xanthomatosis due to the proliferation of non-x histiocytes. Occasional involvement of the upper respiratory system has been reported, but lower respiratory tract involvement is very rare. Here, we present a child with severe involvement of the upper and lower respiratory tract by XD and bronchiectasis in the lower lobes of both lungs. The patient was an 8-year-old boy who was admitted to our hospital because of red-brown papules which developed on the skin and progressive dyspnea. He was diagnosed as having XD by skin biopsy. Physical examination revealed disseminated, numerous yellow-reddish brown papular xanthomas on the forehead and eyelids, around the neck and axillary area, and in the oral cavity and pharynx. He had respiratory distress and clubbing of the fingers. Chest x-rays showed hyperaeration and segmental atelectasis. High-resolution CT of the thorax revealed diffuse thickening of the whole tracheal and bronchial wall, and bronchiectasis in the lower lobes. Flexible fiberoptic bronchoscopy revealed numerous xanthomatous lesions in the nasal cavity, nasopharynx, oropharynx, subglottic area, trachea, bifurcation, both main bronchi, and smaller bronchi. To the best of our knowledge, this is the first report of a child with typical lesions of XD with severe involvement of the lower respiratory tract and bronchiectasis.
Bronchiectasis↗
The respiratory system.
Neurological disorders frequently contribute to respiratory failure in critically ill patients. They may be the primary reason for the initiation of mechanical ventilation, or may develop later as a secondary complication. Disorders of the central nervous system leading to respiratory failure include metabolic encephalopathies, acute stroke, lesions of the motor cortex and brain-stem respiratory centres, and their descending pathways. Guillan-Barré syndrome, critical illness polyneuropathy and acute quadriplegic myopathy are the more common neuromuscular causes of respiratory failure. Clinical observations and pulmonary function tests are important in monitoring respiratory function. Respiratory electrophysiological studies are useful in the investigation and monitoring of respiratory failure. Transcortical and cervical magnetic stimulation can assess the central respiratory drive, and may be useful in determining the prognosis in ventilated patients, with cervical cord dysfunction. It is also helpful in the assessment of failure to wean, which is often caused by a combination of central and peripheral nervous system disorders. Phrenic nerve conduction studies and needle electromyography of the diaphragm and chest wall muscles are useful to characterize neuropathies and myopathies affecting the diaphragm. Repetitive phrenic nerve stimulation can assess neuromuscular transmission defects. It is important to identify patients at risk of respiratory failure. They should be carefully monitored and mechanical ventilation should be initiated before the development of severe hypoxaemia.
Critical Care↗
[Gestosis of the respiratory system?].
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Disease↗