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Biomedical subjects

W Dorsch

Publications and source records attributed to W Dorsch.

48 records · Page 3Linked to original sources
PubMed1981

Continuous recording of intrapulmonary "compressed air" as a sensitive noninvasive method of measuring bronchial obstruction in guinea pigs.

The method presented is based on whole-body plethysmography. The apparatus consisted of two chambers (a = respiratory, b = body chamber) separated by a tight water-filled rubber cuff which was fixed around the head of the animal. Experiments were performed under constant gas conditions: temperature 30 degrees C, 100% relative humidity, the volumes of the two chamber being identical. Volume changes in the chamber (delta Va, delta Vb) were recorded continuously by means of pressure transducers. Respiratory flow was calculated by differentiation of delta Va with respect to time. The three parameters delta Va, delta Vb and respiratory flow allowed the calculation of breathing frequency, inspiration/expiration ratio, (peak) expiratory flow and specific airway conductance. In addition we describe a new parameter indicating bronchial obstruction: a graphical plot of delta Vb against delta Va produces a closed loop, the area of which reflects the degree of airway obstruction, and we read off the parameter we term "compressed air" from this graph. In our hands this parameter was more than ten times as sensitive as other measures of bronchial obstruction. Using this new technique we have carried out pharmacological studies with eicosatetraynoic acid (ETYA), 2-aminomethyl 4-t-butyl-6-iodophenol (MK 447 = radical scavenger), the histamine antagonist clemastine and the histamine antagonist cimetidine. In allergen-tested animals we observed mild protective effects of ETYA when given as an aerosol (3 mg) and pronounced effects of MK 447 (4 mg i.p.). Combined H1 H2-antagonism was much more effective in preventing allergen-induced bronchial obstruction than H1-antagonism alone.

Airway Obstruction↗
PubMed1981

Induction of late cutaneous reactions by skin-blister fluid from allergen-tested and normal skin.

Ten healthy volunteers (five atopic, five nonatopic) and seven patients suffering from allergic bronchial asthma and rhinitis/conjunctivitis as well as showing dual reactions after intradermal or bronchial allergen challenge were investigated. Using the suction blister technique, we obtained skin-blister fluid (SBF) from dual skin reactions 30, 60, 180, and 300 min after allergen injection and from normal untested skin. The biologic activity of SBF was tested by intradermal reinjection of the fluid into the donor. SBF taken from dual skin reactions 30 or 60 min after allergen injection produced late cutaneous reactions (LCRs) quite similar to those induced by the allergen. SBF taken from LCR areas 180 or 300 min after antigen testing had much weaker effects, similar to SBF from untested skin. A possible content of allergen extract in SBF from allergen-tested skin areas was not responsible for the observed effects as demonstrated in passive cutaneous anaphylaxis experiments in monkeys. High doses of SBF from untested skin were able to induce LCRs similar to but weaker than LCRs produced by SBF taken at early phases from dual skin reactions. Similar volumes of autologous heparin-plasma or serum did not induce LCRs. It is concluded that during the initial phase of dual skin reactions, factors are formed that are able to induce LCRs. The generation of these mediators seems to be caused at least in part by the extravasation of plasma.

Adolescent↗
PubMed1980

Levels of complement factors in human serum during immediate and late asthmatic reactions and during acute hypersensitivity pneumonitis.

In 16 asthmatic patients and in four subjects suspected of having hypersensitivity pneumonitis, serum levels of CH50, C3, C4, C5 and factor B were measured before, between 10 and 20 min, between 5 and 7 h and, in the latter group, also 24 h after allergen challenges provoking type I bronchial reactions or acute hypersensitivity pneumonitis. There was a significant decrease in one of the complement factors in two patients during the immediate asthmatic phase, but in no patient during the late asthmatic phase and in no patient with hypersensitivity pneumonitis. On the other hand, significant increases of C3, C4, and/or CH50 were seen in five patients during immediate asthmatic reactions, in seven patients during late asthmatic reactions and in all cases with hypersensitivity pneumonitis. However, with respect to the particular complement factors the vast majority of the patients showed no appreciable change. Investigations of C3 split products, which were done in seven patients gave negative results. No correlations existed between the changes in the levels of complement factors to increases of Raw, decreases of DLCO, size of skin test reactions or RAST scores. The cause and pathophysiological role of the non-uniform behaviour of serum complement levels after inhalation challenges is not yet clear; obviously both consumption and formation of complement factors take place during allergen-induced asthmatic reactions and hypersensitivity pneumonitis.

Adolescent↗
PubMed1980

Effect of topical indomethacin on allergen-induced dual skin reactions.

Twelve asthmatics with dual bronchial and skin reactions after allergen challenge received topical treatment with a 5%-indomethacin cream half an hour before and up to 7 h after intradermal allergen and histamine injections. The erythema during the first 20 min of the wheal and flare reaction (WFR) was not affected, neither were the diameters of wheals and flares. 40 to 60 min after injection we observed a marked reduction of the erythema in histamine- and allergen-tested skin areas of 10 patients. This effect lasted up to the 5th h after injection of high allergen doses. During the fully developed late cutaneous reactions (LCR) no effect of indomethacin on the erythema was observed, the edema of LCR was only insignificantly reduced. These results suggest that the erythema in LCR between the 1st and 4th h is caused, at least in part, by local formation of prostaglandins.

Adult↗