Decrease of T-Lymphocyte Proliferation in Exercise-Induced Asthma

The present study was designed to examine the effect of physical exercise on T-lymphocyte proliferation in patients with exercise-induced asthma (EIA). Indeed, a decrease in different immune functions is described in normal man after exercise. Thirty subjects (10 normal and 20 asthmatic subjects with or without EIA) underwent a submaximal exercise test on an electrically driven treadmill. Before and after this test, ventilatory variables were measured, and venous blood was taken to study plasma histamine (RIA) and spontaneous and phytohemagglutinin (PHA)-pulsed T-lymphocyte proliferation (mononuclear cells isolated on Ficoll-Hypaque; tritiated thymidine incorporation). Ten minutes after the end of the exercise, there was a significant FEV1 decrease only in asthmatic subjects with EIA (mean: 24 +/- 5%). In the same group, the mean plasma histamine level was 0.31 ng/ml-1 (+/- 0.06) before the challenge. It rose to 0.62 ng/ml-1 (+/- 0.14) 10 min after the end of the exercise (P < 0.05), and returned to normal limits 20 min after the test. In this group, there was also a significant decrease (by about 35%) of spontaneous and PHA-pulsed T-lymphocyte proliferation 2 and 4 h after the exercise. By contrast, exercise challenge had no effect on either plasma histamine level or T-lymphocyte proliferation in the normal group. Our results show a rapid and transient increase in plasma histamine in EIA. This was followed 2 and 4 h later by a significant decrease of T-lymphocyte proliferation. A possible relationship between these two phenomena is discussed

Travel Agency Marketing Strategy: Insights from Switzerland

This article provides insight into alternative strategies for travel agencies in a matured travel market with a high Internet penetration. Discounting arguments that claim that there will be no need for travel agents in the future, two possible roles for travel agents can be derived from theory and prior studies in the field: travel agents can survive if they focus on specific specialized services, such as travel consultation (specialization; hypothesizing that systematic differences exist between the usage of travel agents for different travel contexts); and travel agents can survive if they focus on specific segments of the market, such as older travelers (segmentation; hypothesizing that systematic differences exist between the usage of travel agents depending on the personal characteristics of travelers). Results indicate that the use of travel agencies is indeed associated with specific services related to package holidays, transport services, beach or city holidays, as well as destinations travelers are not familiar with. In contrast, no clear association between travel agent use and sociodemographic characteristics of travelers exists. Hence, the findings from this study support the notion that the most promising future for travel agents will lie in specializing in travel contexts and travel components where other booking channels and media are unlikely to be able to offer a full substitute for travel agent services