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Biomedical subjects

J Korpás

Publications and source records attributed to J Korpás.

At least 19 recordsLinked to original sources
PubMed1991

Relationship between the antitussic and analgesic activity of substances.

The authors studied relationship between the antitussic and analgesic activity of substances. The antitussic effect of codeine, tilidine, tramadol and pentazocine has been studied in nonanesthetized healthy cats. The drugs except tilidine, were administered intraperitoneally in a dose of 10 mg/kg body weight. Tilidine was administered intramuscularly in the same dose. Cough induced in nonanesthetized cats by mechanical irritation of laryngopharyngeal and tracheobronchial areas was evaluated by changes of the lateral tracheal pressure. A significant decrease of the subsequent cough parameters was observed after the application of codeine, tilidine, tramadol and pentazocine. Naloxone given 5 min before the application of the drug has not prevented the cough-suppressing effect due to codeine. Naloxone alone administered in a dose of 1 mg/kg body weight has not significantly influenced the experimentally-induced cough reflex in nonanesthetized cats.

Analgesia↗
PubMed1990

[Objective characterization of cough sounds].

Objectification of the amplitude of the cough sound is important in determining its physiological or pathological nature. To achieve this aim an assembly for computer analysis in the time and frequency region was tested in an attempt to substitute the special equipment used at present by less expensive and readily available computer technique. At the same time the possibilities were assessed for using some statistical characteristics as diagnostic parameters in determining pathological changes of the cough sound. The physiological sound of cough was found to yield a hyperbola connecting the peaks of the individual bars of the frequency histogram which in pathological cough was represented by a line descending from left to right. Thus the two types of cough can be objectively distinguished.

Cough↗
PubMed1989

Effects of atropine, acetylsalicylic acid, FPL 55712, and phentolamine on increased histamine responsiveness of cat lung strips under conditions of airway inflammation.

Our recent in vitro studies on airway smooth muscles of cats with turpentine oil inflammation showed an increase of isometric tension of the lung strips to histamine application. This communication describes the effect of atropine, acetylsalicylic acid, FPL 55712, and phentolamine on the histamine contractions of the lung strips derived from control and experimental groups of cats. Pretreatment of the lung strips with atropine and acetylsalicylic acid had no significant effect on histamine induced contraction. FPL 55712 significantly decreased the mean values of isometric contractions after the low doses of histamine in experimental groups of strips. The isometric contractions after higher doses of histamine were not affected by FPL 55712 in both groups of strips. The significant increase of histamine contractions of the lung strips induced by experimental inflammation was reduced by phentolamine. The role of alpha adrenergic receptors in the increased responsiveness of the inflamed lung tissues to histamine is discussed.

Animals↗
PubMed1989

Objective assessment of cough suppressants under normal and pathological experimental conditions.

The influences of the antitussive activity of glaucine were studied in 56 non-anaesthetized cats under normal and pathological conditions. Cough was induced by mechanical stimulation of the airways with a nylon fibre. The authors found that if glaucine was administered at a dose of 5.0, 7.5 and 10.0 mg/kg b.w., i.p., it evoked statistically significant suppression on single cough components. After inflammation of the airways was induced with unsoluted croton oil, no decrease in antitussive activity of glaucine could be observed, according to the number of cough efforts, frequency, intensity of maximal cough effort, and intensity of cough attack during expiration. Glaucine used under such conditions was not found to be powerful enough to suppress either the intensity of maximal cough effort or the intensity of cough attack during inspiration. The antitussive effect of glaucine was stronger under pathological conditions (Staphylococcus-induced inflammation). The antitussive effect of glaucine was approximately the same as with codeine if administered in equal doses.

Animals↗
PubMed1987

Influence of experimentally induced airway inflammation on the reactivity of cat lung parenchymal strips to histamine and acetylcholine.

The reactivity of cat lung parenchymal strips to histamine and acetylcholine in vitro was studied at various stages of inflammation of the airways induced experimentally by the intratracheal administration of turpentine oil or Staphylococcus aureus, both in aerosol form. With histamine, the contractile responses of the lung strips were enhanced depending on the stage of turpentine oil inflammation. Similarly, the lung strips responded more to histamine in the staphylococcal inflammation. The reactivity of the lung strips to acetylcholine remained mainly unaffected by either type of inflammation.

Acetylcholine↗
PubMed1987

Effect of hypoxia and hypercapina on the airways defence reflexes.

In experiments on 10 adult anaesthetized cats (pentobarbital 30 mg.kg-1 i.p.) the effect of stimultaneous hypoxia and hypercapnia was studied on the defence respiratory reflexes of the airways. Expiratory reflex and cough were elicited by mechanical stimulation of the airways mucosa, and the obtained values were evaluated on basis of the intrapleural pressure. Inhalation of the hypoxic-hypercapnic gas mixture (11% + 7% CO2 in N2) for 15 minutes led to a significant decrease of respiratory frequency, tidal volume and PaCO2, while pHa and PaCO2 also decreased significantly together with the intensity of the expiratory reflex and that of cough. Recent studies, showed that in the course of the effect of hypoxia (11% O2) and of hypercapnia (5% CO2), cough intensity decreased, but the change was not significant. The decrease of the intensity of respiratory defence reflexes under hypoxic-hypercapnic conditions might have been due to the changes of centrally controlling structures, or to the effector part of the reflex arc, resulting from fatigue of the respiratory muscles. The possible effect of anaesthesia exerting a significant influence on the intensity and character of airways defence reflexes could not be excluded.

Animals↗
PubMed1987

Tussiphonographic analysis of cough sound recordings performed by Schmidt-Voigt and Hirschberg and Szende.

The cough sound records published by Schmidt-Voigt and Hirschberg and Szende were submitted to tussiphonographic analysis. It has been established that all the recordings of various types of cough sounds registered in airway disease were of pathological character in the tussiphonographic recordings. It has repeatedly been confirmed that tussiphonography is a suitable means for screening of respiratory diseases.

Cough↗
PubMed1987

Measurement of airway resistance in awake cats.

Airway resistance (Raw) measurement with continuous recording was studied in 10 awake cats. The method used was a transducer enabling to incorporate additive resistances by rotating blind. The signals were processed electronically. Part of the measuring device in a pneumotachographic transducer (measurement V') and VT is obtained by integrating V'. Values for mean Raw were read in both parts of the breathing cycle. The experiments have shown that the method could be used in awake cats. Values for mean Rawinsp. were 1.3 +/- 0.24 kPa.l-1.s, Rawexp. of 1.43 +/- 0.26 kPa.l-1.s, end-inspiratory Raw was 1.44 +/- 0.33 kPa.l-1.s and end-expiratory Raw of 1.49 +/- 0.31 kPa.l-1.s.

Airway Resistance↗
PubMed1987

Pharmacological analysis of reactivity changes in airways due to acute inflammation in cats.

Our recent in vitro studies on airways smooth muscles of the cat with turpentine oil inflammation showed the occurrence of a contractile response of tracheal preparations and a significant increase in the isometric tension of lung strips to histamine application. This study was aimed to establish whether histamine H2-receptors participated in the changed in vitro reactivity of the airways smooth muscles of cats suffering from experimentally induced airway inflammation. Pretreatment of control tracheal preparations, control and experimental groups of the lung strips by cimetidine did not change the character of the histamine response. Similarly, the amplitude of histamine relaxation, of the tracheal preparations partially contracted by carbachol was unchanged by experimental inflammation. Clemastine significantly shifted the histamine dose-response curves to the right in both groups of lung strips. However, significant differences in lung strip reactivity between control and experimental groups of cats were not eliminated. Our results do not support the role of histamine H2-receptors in the pathologically increased airway reactivity to histamine in vitro.

Airway Resistance↗
PubMed1987

Age- and body-weight-dependent changes in the reactivity to histamine of the airways smooth muscles in cats.

The relation between age and body weight and the reactivity to histamine of the tracheopulmonary contractile tissues was studied in cats in vitro. The reactivity of the tracheal smooth muscle to histamine decreased with increasing age from the newborn (100%) and one-month-old (57%) to the adult (0%) cat, whereas the amplitudes of contractions of lung strips increased. The amplitudes in adult animals also increased moderately with increasing body weight.

Aging↗
PubMed1987

Effects of antitussive drugs under normal and pathological conditions.

The antitussive effect codeine and 1-propoxyphene have been studied in non-anaesthetized healthy cats and cats with respiratory tract inflammation elicited by undiluted croton oil. The drugs were administered intraperitoneally in doses of 10 and 20 mg/kg body weight. The antitussive effect was studied on the 4th day, after inflammation had set in. Cough induced in nonanaesthetized cats by mechanical irritation of the laryngopharyngeal and tracheobronchial areas was evaluated by changes of the lateral tracheal pressure. Experimentally induced inflammatory changes of the respiratory tract due to the antitussive activity of 1-porpoxyphene were significantly reduced, but that of codeine had not changed at all.

Animals↗
PubMed1987

The tussiphonogram during asthmatic attack.

By tussiphonography the voluntarily induced cough sound was registered in the course of asthmatic attacks and in the state of quinescence. Evaluation of the recordings revealed that in the course of the asthmatic attack, the intensity of voluntarily induced cough sound was significantly decreased.

Adult↗
PubMed1986

Changes induced by severe hypoxia in respiratory defence reflexes in anaesthetized cats.

The authors studied the effects of progressive isobaric hypoxia (FO2 = 0.11, 0.07, 0.06, 0.05, 0.04 and 0.03) on respiratory defence reflexes elicited by mechanical stimulation of the airways in 10 pentobarbital-anaesthetized cats. The intensity of the expiration reflex was already significantly reduced at a hypoxia level of only FO2 = 0.11; the intensity of cough also showed a tendency to decrease. The number of efforts and the intensity of both tracheobronchial (TB) and laryngopharyngeal (LPh) cough fell significantly in hypoxia of FO2 = 0.07. On an average, cough could no longer be elicited at PaO2 = 2.0 +/- 0.06 kPa. The aspiration reflex was found to be the most resistant to hypoxia, and could still be elicited just before hypoxic apnoea developed. During hypoxia with FO2 ranging from 0.21 to 0.06, minute ventilation increased, while the intensity of respiratory defence reflexes diminished. TB cough could not be elicited during hypoxia until the breathing was depressed. It can be seen from the results that the regulatory mechanisms responsible for the intensity of respiratory defence reflexes are less resistant to the consequences of an inadequate systemic oxygen supply than the mechanisms controlling ventilation.

Anesthesia, Intravenous↗