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J W Bloom

Publications and source records attributed to J W Bloom.

57 records · Page 4Linked to original sources

Airway cholinergic responsiveness in rabbits in relation to antigen sensitization and challenge.

The development of bronchial hyperresponsiveness to cholinergic agents in relation to antigen sensitization and repeated antigen challenge was investigated in a rabbit model. Rabbits immunized to produce preferentially specific IgE antibodies had a modest enhancement of their bronchoconstrictive response (measured as an increase in pulmonary resistance) to aerosolized methacholine compared to sham-immunized and unimmunized controls. A further enhancement was observed subsequent to a series of seven antigen challenges given transtracheally, such that the geometric mean dose of methacholine required to increase pulmonary resistance by 100% (PD100 RL) was 89 cumulative breath units (CBU) compared to 372 CBU for sham-immunized controls and 871 CBU for unimmunized controls (p less than 0.05 for ANOVA). Although methacholine also decreased dynamic compliance, the changes were not different among the three groups. Isolated intrapulmonary bronchi from the three groups did not differ in log concentration of methacholine yielding a half-maximal contraction (log EC50). The range of EC50 values was 15-fold compared to a 90-fold range of PD100 RL. In vivo cholinergic responsiveness of the pupillary muscle did not correlate with bronchial responsiveness. Thus, pulmonary antigen challenge of IgE-producing rabbits produced a marked increase in bronchial responsiveness which did not correlate with in-vitro bronchial responsiveness or with in vivo pupillary responsiveness.

Animals↗

Identification of B2 bradykinin binding sites in the guinea pig nasal turbinate.

Specific high affinity BK binding sites in the nasal turbinate of the guinea pig have been demonstrated. Specific [3H]BK binding (10-330 pM) was saturable, and nonlinear least squares analysis indicated the presence of a high affinity binding site with a Kd value of 60 (50-78) pM and a Bmax value of 13.1 = 2.0 fmol/mg protein. In inhibition experiments, D-Phe7-BK (a B2 antagonist) inhibited [3H]BK binding with a Ki value of 23 nM, while des-Arg9[Leu8]-BK (a B1 antagonist) had no effect up to a concentration of 10 microM. These studies indicate the presence of B2 BK receptors in the guinea pig nasal turbinate.

Animals↗