The Experts below are selected from a list of 180 Experts worldwide ranked by ideXlab platform

Malgorzata Szeredaprzestaszewska - One of the best experts on this subject based on the ideXlab platform.

  • supranodose vagotomy precludes Reflex Respiratory responses to serotonin in cats
    Journal of Biomedical Science, 2003
    Co-Authors: Beata Kopczynska, Malgorzata Szeredaprzestaszewska
    Abstract:

    Mediation of the Respiratory Reflex effects of an exogenous serotonin challenge goes beyond the lung vagi and is suggested to involve the nodose ganglia. In the present experiments the effects of an intravenous serotonin challenge on breathing pattern were studied in 8 pentobarbitone-chloralose anaesthetised cats. Bolus injection of serotonin oxalate (50 µg/kg) into the right femoral vein evoked prompt apnoea of 19.2 (±2.4)-second duration in all 8 cats while intact; the apnoea was much shorter after midcervical vagal section (8.1±0.9 s, p<0.001), and was abolished by supranodose vagotomy. In post-apnoeic breaths, the tidal volume was reduced from a baseline of 34.1±4.0 to 13.5±1.1 ml (p<0.001) prior to, and from a baseline of 43.9±5.4 to 33.8±6.6 ml (p<0.01) after midcervical vagotomy; the serotonin challenge did not affect tidal volume following supranodose vagal section (p=0.4). The increase in Respiratory rate found in intact (p<0.001) and midcervically vagotomised cats (p<0.01) was eliminated by the neurotomy above the nodose ganglia. Supranodose vagotomy altered cardiovascular response to serotonin by replacing the fall in blood pressure with an increase. These data suggest that the sequelae of serotonin-induced pulmonary chemoReflex, i.e. Respiratory arrest, cardiovascular changes and post-apnoeic pattern of breathing require intact nodose ganglia.

François Carré - One of the best experts on this subject based on the ideXlab platform.

  • Decreased heart rate variability in transgenic mice overexpressing atrial beta 1-adrenoceptors.
    American Journal of Physiology-heart and Circulatory Physiology, 1996
    Co-Authors: P. Mansier, C. Medigue, Nathalie Charlotte, C. Vermeiren, E. Coraboeuf, E. Deroubai, E. Ratner, B. Chevalier, Jean Clairambault, François Carré
    Abstract:

    Heart rate variability (HRV) depends on various Reflexes, including the baroReflex or Respiratory Reflex. Experimental studies have suggested that the sinoatrial node density in G protein-linked re...

  • Decreased heart rate variability in transgenic mice overexpressing atrial beta 1-adrenoceptors.
    The American journal of physiology, 1996
    Co-Authors: P. Mansier, C. Medigue, Nathalie Charlotte, C. Vermeiren, E. Coraboeuf, E. Deroubai, E. Ratner, B. Chevalier, Jean Clairambault, François Carré
    Abstract:

    Heart rate variability (HRV) depends on various Reflexes, including the baroReflex or Respiratory Reflex. Experimental studies have suggested that the sinoatrial node density in G protein-linked receptors may be involved. Transgenic mice, with a specific eightfold atrial overexpression of human beta 1-adrenoceptor (beta 1-AR), have been generated to evaluate the role of the atrial beta 1-AR density on HRV. The heart rate was monitored using telemetry, and the signal was analyzed using a quantitative time-frequency domain analysis, the smoothed pseudo-Wigner-Ville method, and phase portrait maps. 1) Heart rate was unchanged, but the two normal components of HRV were decreased in transgenic mice. Transgenic mice have an unshortened life span and no arrhythmias. 2) Challenge of the animals by propranolol showed no modulation of the HRV in transgenic mice compared with controls. 3) In isolated atrial strips from transgenic mice, basal contractility was increased and there was no isoproterenol-induced inotropic effect. 4) The basal level of adenosine 3',5'-cyclic monophosphate production was lowered in transgenic mice, suggesting a shift in adenylate cyclase isoforms.

Beata Kopczynska - One of the best experts on this subject based on the ideXlab platform.

  • supranodose vagotomy precludes Reflex Respiratory responses to serotonin in cats
    Journal of Biomedical Science, 2003
    Co-Authors: Beata Kopczynska, Malgorzata Szeredaprzestaszewska
    Abstract:

    Mediation of the Respiratory Reflex effects of an exogenous serotonin challenge goes beyond the lung vagi and is suggested to involve the nodose ganglia. In the present experiments the effects of an intravenous serotonin challenge on breathing pattern were studied in 8 pentobarbitone-chloralose anaesthetised cats. Bolus injection of serotonin oxalate (50 µg/kg) into the right femoral vein evoked prompt apnoea of 19.2 (±2.4)-second duration in all 8 cats while intact; the apnoea was much shorter after midcervical vagal section (8.1±0.9 s, p<0.001), and was abolished by supranodose vagotomy. In post-apnoeic breaths, the tidal volume was reduced from a baseline of 34.1±4.0 to 13.5±1.1 ml (p<0.001) prior to, and from a baseline of 43.9±5.4 to 33.8±6.6 ml (p<0.01) after midcervical vagotomy; the serotonin challenge did not affect tidal volume following supranodose vagal section (p=0.4). The increase in Respiratory rate found in intact (p<0.001) and midcervically vagotomised cats (p<0.01) was eliminated by the neurotomy above the nodose ganglia. Supranodose vagotomy altered cardiovascular response to serotonin by replacing the fall in blood pressure with an increase. These data suggest that the sequelae of serotonin-induced pulmonary chemoReflex, i.e. Respiratory arrest, cardiovascular changes and post-apnoeic pattern of breathing require intact nodose ganglia.

P. Mansier - One of the best experts on this subject based on the ideXlab platform.

  • Decreased heart rate variability in transgenic mice overexpressing atrial beta 1-adrenoceptors.
    American Journal of Physiology-heart and Circulatory Physiology, 1996
    Co-Authors: P. Mansier, C. Medigue, Nathalie Charlotte, C. Vermeiren, E. Coraboeuf, E. Deroubai, E. Ratner, B. Chevalier, Jean Clairambault, François Carré
    Abstract:

    Heart rate variability (HRV) depends on various Reflexes, including the baroReflex or Respiratory Reflex. Experimental studies have suggested that the sinoatrial node density in G protein-linked re...

  • Decreased heart rate variability in transgenic mice overexpressing atrial beta 1-adrenoceptors.
    The American journal of physiology, 1996
    Co-Authors: P. Mansier, C. Medigue, Nathalie Charlotte, C. Vermeiren, E. Coraboeuf, E. Deroubai, E. Ratner, B. Chevalier, Jean Clairambault, François Carré
    Abstract:

    Heart rate variability (HRV) depends on various Reflexes, including the baroReflex or Respiratory Reflex. Experimental studies have suggested that the sinoatrial node density in G protein-linked receptors may be involved. Transgenic mice, with a specific eightfold atrial overexpression of human beta 1-adrenoceptor (beta 1-AR), have been generated to evaluate the role of the atrial beta 1-AR density on HRV. The heart rate was monitored using telemetry, and the signal was analyzed using a quantitative time-frequency domain analysis, the smoothed pseudo-Wigner-Ville method, and phase portrait maps. 1) Heart rate was unchanged, but the two normal components of HRV were decreased in transgenic mice. Transgenic mice have an unshortened life span and no arrhythmias. 2) Challenge of the animals by propranolol showed no modulation of the HRV in transgenic mice compared with controls. 3) In isolated atrial strips from transgenic mice, basal contractility was increased and there was no isoproterenol-induced inotropic effect. 4) The basal level of adenosine 3',5'-cyclic monophosphate production was lowered in transgenic mice, suggesting a shift in adenylate cyclase isoforms.

Franz J Frei - One of the best experts on this subject based on the ideXlab platform.

  • Impact of high concentrations of sevoflurane on laryngeal Reflex responses
    Pediatric Anesthesia, 2017
    Co-Authors: Britta S. Von Ungern-sternberg, Jens Moll, Franz J Frei
    Abstract:

    SummaryBackground Exaggerated defensive upper airway Reflexes, particularly laryngospasm, may cause hypoxemic damage, especially in children. General clinical experience suggests that laryngeal Reflex responses are more common under light levels of anesthesia, and previous clinical studies have shown an inverse correlation between laryngeal responsiveness and depth of hypnosis. However, this seems to be less obvious in children anesthetized with sevoflurane. The aim of this study was to assess the impact of high concentrations of sevoflurane on laryngeal and Respiratory Reflex responses in spontaneously breathing children. Accordingly, we tested the hypothesis that laryngeal and Respiratory Reflex responses were completely suppressed in spontaneously breathing children when anesthetized with sevoflurane 4.7% (=MACED95Intubation) as compared with sevoflurane 2.5% (=1 MAC). Methods In this prospective observational study, we tested the hypothesis that the incidence of laryngospasm evoked by laryngeal stimulation is diminished under high concentrations of sevoflurane. Following Ethics approval, trial registration, and informed consent, 40 children (3–7 years) scheduled for elective surgery participated in the trial. All children received sevoflurane 2.5% (1 MAC) and 4.7% (ED95Intubation) in random order with 5-min equilibration between the states. Under both conditions, distilled water was sprayed under bronchoscopic view onto the larynx. Potential laryngeal and Respiratory Reflex responses were assessed offline by a blinded reviewer. Results Laryngospasm (episodes lasting >10 s) occurred in 12/38 (32%) of the patients anesthetized with sevoflurane 2.5%, vs 7/38 (18%) in those anesthetized with sevoflurane 4.7% (difference: OR 3.5; 95% CI [0.72–16.84], P = 0.18). All other Reflex responses (coughing, expiration Reflexes, and spasmodic panting) were infrequent and were similar among the examined concentrations. Conclusion Against our hypothesis, laryngospasm could still be observed in 18% of children under the higher concentration of sevoflurane (4.7%, ED95Intubation).

  • the effect of intravenous lidocaine on laryngeal and Respiratory Reflex responses in anaesthetised children
    Anaesthesia, 2013
    Co-Authors: B S Von Ungernsternberg, K Keller, Franz J Frei
    Abstract:

    Summary We studied the effect of intravenous lidocaine on laryngeal and Respiratory Reflex responses in children anaesthetised with sevoflurane. We tested the hypothesis that the incidence of laryngospasm evoked by laryngeal stimulation is temporarily diminished after the administration of lidocaine. Forty children, aged between 25 and 84 months, were anaesthetised with sevoflurane and breathed spontaneously through a laryngeal mask airway. Respiratory Reflex responses were elicited by spraying distilled water onto the laryngeal mucosa at three time intervals: (i) before lidocaine was administered (baseline); (ii) at 2 min and (iii) at 10 min following the intravenous administration of a bolus of lidocaine 2 mg.kg )1 . A blinded reviewer assessed the evoked responses. The incidence of laryngospasm was reduced from 38% at baseline to 15% 2 min after lidocaine administration (p < 0.02) and 18% 10 min after lidocaine administration (p = 0.10). We conclude that intravenous lidocaine significantly reduced the incidence of laryngospasm but that the effect was short-lived.

  • Respiratory Reflex responses of the larynx differ between sevoflurane and propofol in pediatric patients
    Anesthesiology, 2005
    Co-Authors: Christine Oberer, Britta S Von Ungernsternberg, Franz J Frei
    Abstract:

    Background:The effects of anesthetics on airway protective Reflexes have not been extensively characterized in children. The aim of this study was to compare the laryngeal Reflex responses in children anesthetized with either sevoflurane or propofol under two levels of hypnosis using the Bispectral