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At least 19 recordsLinked to original sources
PubMed1976

[Mathematical simulation of the respiratory system (author's transl)].

The respiratory system is described as a feedback control system. The controller consists of the peripheral chemoreceptors and the central chemosensitive structures, the respiratory centre in the medulla oblongata and the thorax-lung pump which they drive. The controlled system is comprised of three compartments (lung, brain and the remaining tissue) connected by the blood circulation. The controlled values are arterial pH and arterial O2 partial pressure and cerebral extracellular pH. Earlier models have been improved by: (1) the dead space description, (2) the thermodynamic formulation of the CO2 dissociation equation and the simple but accurate O2 dissociation equation of the blood, (3) the alteration of the CO2 dissociation equation for the brain and the remaining tissue to accommodate recent results, (4) the application of the one-receptor-theory of central chemosensitivity, (5) the pH dependence of brain circulation, (6) the bicarbonate exchange between blood and extracellular fluid of the brain and (7) the introduction of variable circulation times. Respiratory and metabolic disturbances of the respiratory system are analyzed. The mathematical formulation of the respiratory system is a differential difference equation system. In the steady state the experimental results are reproduced fairly well. A slight discrepancy is found in the simulation of metabolic acidosis. Apparently we have assumed the sensitivity of the peripheral chemoreceptors to be too large so that the respiratory response is not correctly predicted. In the numerical solution there is an overshoot in the on-transient and a damped oscillation in the off-transient of the alveolar CO2 partial pressure during respiratory acidosis. We have varied the parameters to make deviations small. The best agreement seems to result, if the central threshold is near the normal extracellular pH of the brain. A further deviation from experimental findings is that the cerebral CO2 and H+ concentration, the blood circulation of the brain, the alveolar O2 partial tension and the ventilation show a slight oscillation in the off-transient. Except for these discrepancies the experimental results, especially the stability of the extracellular pH of the brain, are reproduced fairly well. During hypoxia there are deviations form the experimental results if the central residual activity is constant and the central threshold deviates from the normal extracellular pH of the brain. But if the central residual activity is pH dependent and if the central threshold is equal to the normal extracellular pH of the brain, then the time course of VE and the other variables agree fairly well with experimental results. There is also a good correspondence between the theoretical and experimental data during hyperoxia. During metabolic acidosis the time constant of the bicarbonate exchange between blood and extracellular fluid of the brain is important. If a time constant of one minute is assumed, then the predicted and the experimental results correspond sufficiently well.

Bicarbonates↗
PubMedDate not supplied

Role of serotonin in the regulation of respiratory system function.

Role of serotonin in the regulation of respiratory system function. Acta Physiol. Pol., 1978, 29 (2): 131--138. This study examined respiratory centre reflector excitability, the electrical activity of respiratory muscles, outer breathing, pH and arterial blood gas composition under conditions of experimentally induced serotonin excess or deficiency in 48 dogs. It was found that excess of serotonin in the animals leads a strenghthening of respiratory action in terms of increased respiratory centre bioelectrical excitability, muscular electrical activity and outer respiratory indices, such as frequence, volume and lung ventilation per min. In addition the pH of blood shifted to alkalic and oxygen tension of the blood increased while CO2 tension of the blood decreased.

Animals↗
PubMed1975

The composition of connective tissue macromolecules from bovine respiratory system.

Connective tissue macromolecules, glycosaminoglycans, glycoproteins, collagen, and elastin were isolated from different parts of the respiratory system and characterized. The materials included bronchiolar tissue, gas-exchange tissue, lung pleura, and tracheal mucosa. The similarity of the macromolecular composition of lung pleura and tracheal mucosa suggests a common cellular component in these structures. The high concentration of GAG and collagen in bronchiolar tissue is consistent with the cartilagenous nature of this tissue. Particularly interesting is the high content of heparin in all pulmonary structures, a relatively greater content of hyaluronic acid in gas-exchange tissue, and a high content of heparan sulfate and dermatan sulfate in vascular tissues. Elastin also occurs as a major fibrous structure. Although the biologic role of these connective tissue macromolecules has not been established, certain functional relationships are inferred.

Animals↗
PubMed1975

[Leeches in the respiratory system (author's transl)].

The leech as a foreign body and parasite in the human respiratory tract occurs principally in the Mediterranean countries, in Africa and Asia. It reaches the respiratory tract when water is drunk directly from rivers, lakes, etc. Ignorance of this fact may cause diagnostic difficulties leading to errors in treatment. Anaemia and respiratory obstruction due to leeches cause danger to health and life, especially in children. Fatalities have been known. Treatment consists of endoscopic removal of the parasite, which may be technically difficult, especially when the leech is in the region of the larynx and thus presents dramatic conditions for the procedure. A series of 120 cases treated in Algeria between 1962 and 1971 is presented.

Age Factors↗
PubMed1976

The branched respiratory system of photosynthetically grown Rhodopseudomonas capsulata.

Various respiratory electron transport activities of Rhodopseudomonas capsulata were studied in membrane fragments prepared from photosynthetically grown cells of a parental strain and two terminal oxidase-defective mutant strains. The NADH and succinate oxidase activities of the mutant having a functional N,N,N1,N1-tetramethyl-p-phenylenediamine oxidase, M6, were consideraly more sensitive to inhibition by either antimycin A or cyanide than the corresponding activities of the mutant lacking a functional N,N,N1,N1-tetramethyl-p-phenylenediamine oxidase, M7. The parental strain, Z-1, but not the mutants, showed biphasic inhibitory responses of NADH and succinate oxidase activities with either antimycin A or cyanide. In certain reactions no differences in inhibitor susceptibility were found among the strains tested, implying that the pathways involved were unaffected in the mutants. In this category were the actions of rotenone on NADH oxidase, antimycin A on cytochrome c reductase and, in M6 and Z-1, cyanide on N,N,N'N'-tetramethyl-p-phenylenediamine oxidase. These results suggest that the respiratory chain of the parental strain branches at the ubiquinone-cytochrome b region into two pathways, each branch goes to a distinct terminal oxidase, and either may be blocked independently by genetic mutation.

Antimycin A↗
PubMed1978

Heat injuries to the respiratory system.

A steam-tube of the main boiler exploded on a ship lying in the harbour of Hamburg. The steam temperature was 283 degrees C. Cutaneous and severe inhalational scalding occured in the 27 fatalities, the men dying after different intervals. This paper deals with the pathological findings in the respiratory passages and the lung, describing the topographical extent of direct thermal injury and the temporal course of tissue reactions. In cases of instantaneous death coagulation necrosis of the tracheal and bronchial wall was found to extend to alveolar ducts in central parts of the lung. The lung parenchyma showed marked congestion, alveolar edema and desquamation of alveolar epithelial cells. Death occured due to acute pulmonary dysfunction and shock. Lethal complications following the period of primary shock consisted of fulminant confluent bronchopneumonia, the hyaline membrane syndrome or the onset of desquamative interstitial pneumonia. These changes rendered it difficult to evaluate the effects of the heavy cutaneous scalding on the pathological course of inhalational injuries in those surviving for longer periods.

Adult↗
PubMed1979

Histopathologic and clinical abnormalities of the respiratory system in chronic hashish smokers.

Thirty chronic hashish smokers (mean age-20 years) with respiratory symptoms and six control subjects who were nonhashish smokers were evaluated by history, physical examination, bronchoscopy, and bronchial biopsy. Twenty-three (23) of 23 (100 percent) patients who smoked hashish plus cigarettes had one or more histopathologic abnormalities of basal cell hyperplasia, atypical cells, or squamous cell metaplasia. Only one of seven (28.6 percent) hashish smokers who smoked cigarettes, one of three (33.3 percent) cigarette smokers who smoked no hashish, and zero of three (0 percent) nonsmokers showed one or more of the same histopathologic lesions (p less than .05). Hashish smoking when combined with cigarette smoking appeared to have more deleterious pulmonary effects than either hashish or cigarettes smoked alone, and the abnormal histopathologic lesions found in these smokers are identical to those frequently associated with later development of emphysema and carcinoma of the lung.

Adult↗
PubMed1975

Immunity to infections of the respiratory system in man and animals.

Itis probable that RS virus is an important etiological agent in the bovine respiratory disease syndrome. This is the conclusion of groups of workers in Europe and Japan. In this country, significant levels of neutralizing antibody have been detected in 81 percent of cattle tested, while paired sera groups showed seroconversions of between 17 and 29 percent. RS virus has also been isolated from diseased calves and such isolates produce pyrexia and rhinitis in experimentally infected calves. The virus is localised in the respiratory tract. Serum antibody responses have not been consistent but it is likely that moderate serum antibody levels indicate that the animal is protected. These antibody levels can be achieved by injection of a formalin inactivated antigen. Calves vaccinated in this way showed no definite evidence of exacerbation of disease when challenged with infectious virus.

Animals↗
PubMed1975

Oxidation processes and ubiquinone localization in the branched respiratory system of mi-1 mutant of Neurospora crassa.

1. Stimulation of succinate oxidation in mi-1 mitochondria by Mg2+ and Pi is abolished on uncoupling, which points to the energy-linked activation of succinate oxidation. 2. Mitochondria exhibited respiratory control with succinate and NADH when the cyanide-insensitive oxidation was inhibited by salicylhydroxamic acid (SHAM). SHAM lowered the oxidation rate with NADH and succinate to the same level, though the NADH oxidation rate was 2.5 times as high as with succinate. 3. Despite the high stimulation of succinate oxidation via the SHAM-sensitive pathway in the active and controlled state of mitochondria, the redox state of UQ in all metabolic states remains unchanged. On inhibition of the cyanide-insensitive pathway, UQ reduction is greatly increased only in the controlled and active state. With NADH as a substrate, UQ does not respond to the metabolic states of mitochondria. 4. The redox changes of cytochrome c parallel those of UQ. 5. Branching of the respiratory chain in mi-1 mitochondria is discussed.

Adenosine Diphosphate↗
PubMed1975

The respiratory system of Chromobacterium violaceum grown under conditions of high and low cyanide evolution.

The particulate fraction of disrupted Chromobacterium violaceum grown under cyanide-evolving conditions was unable to oxidize ascorbate plus N,N,N',N'-tetra-methyl-p-phenylenediamine (TMPD), but oxidized NADH and succinate by a linear respiratory pathway which was very resistant to inhibition by cyanide. When the bacteria were grown under conditions where little cyanide evolution occurred, particulate fractions developed the ability to oxidize ascorbate-TMPD by a pathway highly sensitive to cyanide inhibition; respiratory activity with NADH and succinate proceeded via both the cyanide-sensitive and-resistant pathways. Studies with respiratory inhibitors, and the cytochrome compositions of the fractions derived from cultures grown under both conditions, are presented. A soluble, carbon monoxide-binding cytochrome c was found, and this appears similar to those found recently in Beneckea natiegens, methylotrophic bacteria and the marine pseudomonad B16.

Antimycin A↗