Mortality in patients with f-IDH is significantly higher than in those without such events. After adjustments for covariates, however, there is no independent effect of frequent or occasional episodes of IDH on mortality.
Nine patients with bronchial asthma who had early and late falls in forced expiratory volume in one second (FEV1)(10 minutes and six hours, respectively) after inhalational challenge with specific antigens were studied for the presence of circulating neutrophil chemotactic activity (NCA). NCA was detected during both the early and the late asthmatic responses; the time course of appearance of NCA in the circulation paralleled that of the falls in FEV1. In contrast, five patients with asthma who had early reactions had only a single early peak of NCA, with no further rise for up to 24 hours. The NCA detected during early and late reactions eluted with macromolecules of an estimated molecular weight greater than 500,000 daltons when applied separately to columns of Sephadex G-200. Since high-molecular-weight NCA is believed to be associated with mast cells, these observations support the view that mediators of hypersensitivity are released in both the late and the early asthmatic responses.
A B S T R A C T A heat-stable neutrophil chemotactic factor (NCF) has been identified in the serum of 13 atopic asthmatic subjects after treadmill exercise. Peak activity was detected at 10 min and returned to prechallenge values by 1 h. No NCF activity was detected in the sera of three nonasthmatic atopic or four normal nonatopic individuals performing the same task. NCF produced by exercise (NCFEX) had a similar timecourse of release to NCF provoked by specific antigen (NCFAG). The appearance of circulating NCFEX and NCFAG closely paralleled the fall in peak expiratory flow rate/forced expiratory volume in 1 s (PEFR/ FEVI). Histamine challenge in atopic asthmatics at concentrations giving a comparable change in PEFR/ FEVy to that evoked by exercise or inhaled antigen was not associated with the appearance of circulating NCF. In seven subjects NCFEX release was inhibited by prior administration of disodium cromoglycate. NCFEX and NCFAG eluted as single peaks of activity when applied separately to columns of Sephadex G-200, and both were an estimated 750,000 daltons. NCFEX and NCFAG also eluted as single peaks of activity, at between 0.15 and 0.30 M NaCl, following anion exchange chromatography on DEAE-Sephacel (pH 7.8). The isoelectric points of NCFEX and NCFAG were virtually identical (between pH 6.0 and 6.5) as determined by chromatofocusing on Polybuffer Exchanger 94. The activities of NCFEx and NCFAG were substantially reduced, in both a time-and dose-dependent fashion, after incubation with trypsin and chymotrypsin. Partially purified NCFEX and NCFAG promoted both stimulated random migration (chemokinesis) as well as directional migration (chemotaxis).These experiments indicate that NCFEX and NCFAG might be identical substances and raise the possibility
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