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Biomedical subjects

J B Andersen

Publications and source records attributed to J B Andersen.

At least 109 records · Page 6Linked to original sources
PubMed1980

Demonstration of intersegmental respiratory bronchioles in normal human lungs.

Intercommunications between small airways of adjacent bronchopulmonary segments were studied morphologically in six normal human lungs. Following fixation 3 mm-wide catheters were wedged through the segmental bronchi and corrosion casts were made using different colours of a cold-curing resin (Technovit). The lung tissue was corroded away with concentrated hydrochloric acid and the intersegmental area studied. The resin had crossed from one segment to another in most casts especially in the lower lobe, and in some the junctions between different colours were apparent in small airways with a diameter of 80 to 150 micrometers. These airways had a few alveolar openings in their walls and presumably are intersegmental respiratory bronchioles. This study suggests free communication between small airways of neighbouring segments. It further suggests that collateral ventilation might be of importance even in normal lungs.

Bronchi↗
PubMed1979

Recruiting collapsed lung through collateral channels with positive end-expiratory pressure.

We studied reinflation of collapsed parts in excised normal human lungs through both the ordinary bronchial route and through collateral channels. A model of atelectasis was made either by simple collapse or by applying a positive pressure to the pleura and a negative to the airway. Five different ventilatory patterns were used for reinflation: simulated normal breathing with and without continuous positive airway pressure (CPAP), simulated deep breathing and mechanical ventilation with and without positive end-expiratory pressure (PEEP). All methods, except normal breathing without CPAP, reinflated the collapsed part with pressures well within the range used clinically. The most effective way of re-expanding collapsed lung was the application of CPAP during simulated normal breathing or PEEP during mechanical ventilation, which required smaller transpulmonary pressure swings than the other methods. A comparison between CPAP and PEEP showed CPAP to be preferable. Collateral reinflation occurred just as readily as normal reinflation and the results suggest that collateral reinflation is the primary choice. This route of reexpansion also has a potential secretion clearing effect in that pressure is built up distal to an obstruction.

Adult↗
PubMed1979

Resistive breathing training in severe chronic obstructive pulmonary disease. A pilot study.

We studied the effects of resistive breathing in 10 patients with long-standing, severe disabling COPD. Small increases in inspiratory resistive load resulted in diaphragmatic fatigue and failure in all patients. Fatigue was detected using the frequency spectrum analysis of an EMG signal obtained with surface electrodes. Failure was defined as an inward displacement of the abdomen during inspiration, i.e. incoordination of thoracoabdominal motion. The patients trained for one half hour daily for 4 weeks, breathing into a simple device, where they inspired against a resistive load that produced some incoordinated breaths. After 4 weeks this load was increased, if possible, and another 4-week training period started. All patients improved with training, i.e. higher resistances could be tolerated without signs of fatigue and failure. In addition most patients claimed that training had helped them in their daily living; they were able to do more without getting short of breath. The device helped expectoration, possibly owing to the effect of the small expiratory resistance.

Aged↗
PubMed1975

Beclomethasone dipropionate aerosol treatment of hay fever. A dose-response investigation.

In a controlled, double-blind study 20 children and adults, suffering from summer hay fever, were treated intranasally with a daily dose of 200 mug, 300 mug or 400 mug beclomethasone dipropionate (Beconase, Becotide Nasal) or with placebo for 2 weeks during the hay fever season. No beneficial effect of the placebo treatment was observed. In patients treated with 200 mug and 300 mug beclomethasone dipropionate a day there was a moderate decrease in nasal symptom scores and in use of antihistamine tablets. As the results indicated 400 mug a day to have the most pronounced effect on nasal symptoms, this dosage is recommended for children as well as adults suffering from summer hay fever.

Administration, Intranasal↗