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Biomedical subjects

D Cypcar

Publications and source records attributed to D Cypcar.

5 recordsLinked to original sources

Rat eosinophils: isolation and characterization of superoxide production.

Studies with isolated cells are important to the understanding of mechanisms by which eosinophils participate in allergic inflammation. Due to species variability, isolation techniques and cell biology need to be defined for each source. We developed methods to obtain rat eosinophils with purity and viability exceeding 90%, characterized the superoxide anion production of these cells in response to standard activators, and compared these results with those previously obtained in our laboratories with the use of human eosinophils. Rat eosinophils responded vigorously to phorbol myristate acetate and poorly to platelet-activating factor and to N-formyl-methionyl-leucyl-phenylalanine, parallel to the responses of human eosinophils. In contrast, rat eosinophils responded unlike human eosinophils to other activators, having a larger response to calcium ionophore A23187, a smaller response to serum-treated or serum-opsonized zymosan, and a negative rather than positive modulatory effect of cytochalasin B. We conclude that rat eosinophils can be obtained in high purity and with intact responsiveness to a number of different activators.

Animals

Asthma and exercise.

There is evidence that the overall prevalence of asthma is increasing in the general population. Asthma is the leading cause of chronic illness and the most common chronic respiratory disorder in children. Given sufficient exercise intensity, exercise can trigger acute exacerbations in virtually all individuals with asthma. Heat loss, water loss, postexertional airway rewarming, and the role of several mediators have been proposed as possible mechanisms responsible for the airway obstruction induced by exercise. Exercise-induced asthma can be easily diagnosed and treated in the majority of patients. Physical training should be part of the asthmatic patient's overall plan of management. When properly treated, asthmatic individuals should be able to participate or compete in the majority of sports.

Algorithms

Steroid-resistant asthma.

The treatment of patients with asthma that is resistant to corticosteroids represents a therapeutic challenge, because corticosteroids are the most potent and potentially effective medications for severe asthma. Recent investigations have identified several functional defects in mononuclear cells and T lymphocytes isolated from patients with corticosteroid-resistant asthma, including abnormalities in proliferation, activation, and cytokine production. The development of medications with immunomodulatory effects on specific cellular functions represents an exciting step for more efficacious treatment for such patients.

Asthma

The impact of respiratory infections on asthma.

It is apparent that the effects of viral respiratory infections on the development of airway hyperresponsiveness are multiple and interrelated and involved the production of viral specific IgE, upregulation of leukocyte inflammatory activity, enhancement of the factors involved in the generation of late phase allergic responses, altered beta-adrenergic and cholinergic nervous system activity, and damage to the airway epithelium. The summation of these effects is the development of airway inflammation rather than a direct effect on bronchial smooth muscle, per se. An understanding of this pathogenesis underscores the relative importance of anti-inflammatory rather than antimicrobial therapy in viral-induced exacerbations in asthma symptoms.

Adolescent