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Biomedical subjects

I Zimmermann

Publications and source records attributed to I Zimmermann.

32 records · Page 2Linked to original sources
PubMed1977

Effect of unilateral vagus blockade on allergen-induced airway obstruction: results of short- and long-term experiments.

Unilateral application of ascaris extract on segment bronchus as the influence of contralateral vagus blockade on reflex bronchoconstriction was studied on four boxer dogs in a first group (A) of experiments: ascaris extract was applied in liquid form directly through a catheter into the right segment bronchus. This application was repeated after contralateral vagus blockade and once more after its lavage. All the animals showed an increase of airway resistance under local application of ascaris extract which could not be avoided by contralateral central vagus blockade. In the second group (B) isolation of unilateral vagus for reproducible performance of blockade as a long-term model was investigated in three boxer dogs for 7 weeks and the influence of this method of unilateral vagus blockade on exposure to allergen aerosol was studied. The unilateral blockade of the nerve vagus was again always successful in decreasing the reflex bronchoconstriction following allergen inhalation. The effect of unilateral section of nervus vagus 3 weeks after this vagotomy was tested on two boxer dogs. Reflex bronchoconstriction following ascaris extract inhalation can be avoided by unilateral section of the nervus vagus the first time after section. Three weeks after this unilateral vagotomy, the reflex bronchoconstriction becomes managed by the remaining vagus trunk to the same degree as observed by bilateral intact vagi.

Acetylcholine↗
PubMed1977

Relationship between pulmonary embolism, airway obstruction and hypersensitivity of the airways in dogs: influence of partial vagus nerve blockade.

Experiments in dogs showed an increase in deltaPoes/100 ml TV after embolization which returns to normal after blocking the vagus nerves, indicating an increase in airway resistance. A marked sensitization to ACh inhalation by embolism with both blood clots and glass beads was demonstrated. This hypersensitivity is vagus-dependent.

Acetylcholine↗
PubMed1977

[Bronchomotoric in antigen induced airway obstruction (author's transl)].

Ascaris suum extract inhalation causes bronchoconstriction in dogs. Following this reaction, the bronchi stay oversensitive against acetylcholine for at least 7 h. Electrical stimulation of the peripheral end of a nervus vagus after cutting supports the meaning that the bronchoconstriction will be caused mainly by challenge of sensory receptors. The reflex way runs through the nervus vagus. Sensitization of the bronchial tree means sensitization of the sensory receptors. Results of the arterial blood gases correspond to earlier results which showed two parts of the bronchial tree: the vagus-controlled part is mainly respnsible for the airway resistance, the vagus-noncontrolled part is mainly responsible for the regulation of the ventilation/perfusion relationships.

Acetylcholine↗
PubMed1976

Antigen-induced airway obstruction and the influence of vagus blockade.

Respiratory hypersensitivity to Ascaris antigens is carried out on 9 dogs. The participation of vagus reflex on this respiratory distress is studied in 4 of these dogs. The dogs were exposed initially to Ascaris aerosol, then to egg albumin and NaCl aerosol for control, and once more to Ascaris aerosol after bilateral vagi blockade and lavage, respectively. The principal parameters studied were deltaPoes (mm Hg)/100 ml TV as a measurement of flow resistance in the airways, and respiratory rates (Poes=changes of oesphagus pressure; TV=tidal volume). All the animals presented a significant respiratory distress with Ascaris aerosol, which could be clearly avoided with the central bilateral blockade of nervus vagus.

Aerosols↗
PubMed1976

Effect of ascaris extract applied intravenously, on segment bronchus and the influence of ipsilateral vagus blockade.

Respiratory hypersensitivity and systemic effects after local application of Ascaris suum extract on the segmental bronchus and after its intravenous infusion are studied on four boxer dogs. Influence of ipsilateral vagus blockade on the respiratory hyperreactivity after intrabronchial application of ascaris was also investigated on the same dogs. Ascaris extract was applied in liquid form directly through a catheter into the right segmental bronchus. Egg albumin was applied in the same way for control. Local application of ascaris was repeated after ipsilateral central vagus blockade and once more after recovering vagus effect by lavage. At the end of the experiments ascaris extract was infused intravenously. The parameters studied were: deltaP(oes) mm Hg/100 ml TV (as a measurement of flow resistance in the airways), respiratory rates, arterial blood gases and pH, heart frequency, systemic blood pressure and histamine concentration per milliliter of plasma. All the animals presented a remarkable respiratory distress with local ascaris application, which could be clearly avoided with ipsilateral central vagus blockade. This respiratory hyperreactivity was not observed after intravenous infusion of ascaris extract, but a significant systemic effect, which was not the case after local application, could be observed.

Airway Resistance↗
PubMed1976

Dynamic surface tension properties of mixed lecithin-cholesterol films related to the respiratory mechanics.

A bubble method was used to record dynamic area/surface tension diagrams of mixed lecithin-cholesterol films prepared at different weight ratios. The lecithin/cholesterol weight ratios were: 1:2, 1:1, 4:1, 6:1, 8:1 and 12:1. The minimum surface tension is about 20 dyn/cm for all weight ratios at amplitudes of 75, 25, 12.5, 6 and 3% area oscillation. The maximum surface tension depends on both the amplitude of area oscillation and the lecithin/cholesterol weight ratio. The maximum surface tension increases with increasing amplitude. At the amplitudes 25, 12.5, 6 and 3% the maximum surface tension is significant higher at the weight ratios 1:2 and 1:1 compared to the other ratios. In addition, equilibrium surface tensions during interruptions of the oscillation at maximum and minimum area were recorded. The equilibrium surface tension increases with increasing amplitude up to 25% area oscillation. A static hysteresis seems to remain. Some consequences regarding the pulmonary respiratory mechanics are discussed.

Cholesterol↗
PubMed1976

Effect of unilateral vagus blockade on antigen-induced airway obstruction.

Respiratory hypersensitivity and the effect of unilateral vagus blockade on the same, after the use of Ascaris extract aerosol, are studied in three boxer dogs with spontaneous reactivity to this aerosol. The dogs were exposed initially to Ascaris extract aerosol, and this exposure was repeated after unilateral vagus blockade and after its lavage. The principal parameters, deltaPoes (mm Hg)/100 ml TV, are given as a measurement of airway flow resistance and respiratory rates. The spontaneous respiratory distress observed in all the animals after exposure to the mentioned aerosol was avoided with unilateral blockade of the nervus vagus.

Aerosols↗