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Biomedical subjects

M S Islam

Publications and source records attributed to M S Islam.

At least 145 records · Page 8Linked to original sources
PubMed1978

Role of spreading-factor (hyaluronidase) on bronchial response to acetylcholine challenge in dog.

Patients with non-specific chronic lung diseases are very sensitive against external challenge. Experiments in human volunteers and in animals it has been shown that many substances can make bronchial system hyperreactive without causing any direct effect. The mechanisms involve in the process of hyperreactive bronchial system are, so far, not clear. It is conceived in this study that membrane permeability might play an important role in this process. This possibility has been studied in anesthetized dogs by subjecting them to hyaluronidase aerosol. This enzyme is supposed to change the membrane permeability by acting on the ground substance. The animals were first challenged with acetylcholine to obtain the basic responsiveness. Then the animals were subjected to hyaluronidase aerosol and challenged with acetylcholine again. Results confirm the hypotheses that membrane permeability plays an important role in hyperreactive bronchial system.

Acetylcholine↗
PubMed1977

Respiratory damage caused by long-term inhalation of high concentration of sulphur-dioxide in dogs.

It has been tried in this study to produce chronic obstructive bronchitis in dogs by exposing them to high concentrations of SO2. The study was extended to 175 days and during that period the animals were exposed to 300-500 ppm SO2 for a total of 435 h. None of the three dogs developed serious respiratory damage. Most of the symptoms were transitory. Histological examinations showed increased number of goblet cells in trachea, main- and lobar bronchi and a slight alteration of the bronchial glands.

Acetylcholine↗
PubMed1977

[Airway resistance and lung volumes (author's transl)].

Whole-body plethysmography for measuring airway resistance and intrathoracic gas volume is a valuable tool for diagnosing pulmonary and airway functions. It is desirable to know momentary airway resistance in the course of a forced expiration and vital capacity in relation to predicted and actual thoracic gas volume as well as predicted and actual total capacity. This is a reliable means of discovering limitations of lung ventilation despite normal airway resistance during normal ventilation. With a computer and plotter attached to a whole-body plethysmograph such volume-airway resistance curves can be rapidly and well reproduced without stressing the test person. In addition, it also makes it possible to measure routinely the volume resistance breaking point (largely comparable to "closing capacity") even in ill patients.

Airway Resistance↗
PubMed1977

Mechanism of increased tracheo-bronchial response to inhalative acetylcholine aerosol in pulmonary vascular congestion and unilateral pulmonary artery occlusion.

The study was carried out in anesthetized, intubated and spontaneously breathing dogs. The aim of this study was to examine the responsiveness of the tracheo-bronchial system to inhalative ACh. It was considered that any change in ACh-sensitivity signifies the involvement of receptors in the lung itself. Increased pressure in the right heart and main pulmonary artery did not affect the ACh-sensitivity. Whereas, the sustained pulmonary vascular congestion produced by blocking the ascending aorta or by glass bead embolism provoked greater ACh-sensitivity. Increased ACh-sensitivity was also observed in unilateral pulmonary artery occlusion. ACh-sensitivity was greater in the later part of occlusion or vascular congestion and persisted even after the occlusion or block was withdrawn. It is concluded that the increased ACh-sensitivities in pulmonary vascular congestion and in unilateral pulmonary artery occlusion are due to the formation of edema and atelectasis respectively. Anyway, the disturbance of the metabolism of the receptor cells around the small vessels of the lung circulation seems to be essential.

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↗
PubMed1976

[Reaction of the cardio-respiratory-system following acetylcholine inhalation and the dependency from the body position on anaesthetised dogs (author's transl)].

The bronchomotoric reaction following ACH-aerosol in low concentrations is dependend on the position of the body on dogs. Up till one maximal reaction the increase of the airway resistance is always stronger in the lateral position. Nevertheless the breathing minute volume is constant. Concentration reaction curves will be shown. Arterial blood gases, heart rate, and pressure in the arteria femoralis were also measured. The different strongness of the reaction following ACH-inhalation will be caused by the predominantely unilateral ventilation of the animals in the lateral position.

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

Differential diagnosis of ventilatory disorders with the help of volume/flow diagram.

Volume/flow (V/v) diagrams obtained from 82 healthy and pulmonary diseased subjects were analyzed. A formula had been worked out on the basis of determined slow vital capacity, for the calculation of maximum forced expiratory flow (VEmax). The expiratory volume/flow curves were used for the computation of lung conpliance (C1). These calculated values of VEmax and C1 were highly correlated to the measured values. It is concluded that these calculated values would provide a good index for the preliminary differential diagnosis of the pulmonary disorders.

Airway Resistance↗
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

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↗