To elucidate whether systemic reactions (SR) to drugs should be included in the atopic status in epidemiological studies, we compared the distribution of atopy in subjects with or without a history of SR to drugs. The studied population comprised 2067 adults, 20 to 60 years old, visiting a health care center for a check-up examination. The protocol included a questionnaire related to history of SR to drugs and a Phadiatop test which evaluates on a blood sample the presence of specific IgE against common aeroallergens. Overall, 14.7% of the study group, including 66% women, reported reliable histories of SR to drugs. The cumulative prevalence of asthma, hay fever and childhood dermatitis was higher in the SR group. By contrast, the percentage of positive Phadiatop tests was similar in subjects with or without a history of SR. Thus atopy, defined by an objective criterion, i.e. the presence of specific IgE against common aero-allergens, is not associated with the occurrence of SR to drugs. Such a history should not be included as part of the atopic status.

Exposing seedlings of the flax, Linum usitatissimum L., to a variety of weak environmental stresses plus a 2-day calcium deprivation triggers the common response of production of epidermal meristems in the hypocotyl. Here, we show that the same response was induced by a 1 min cold shock. Epidermal meristem production was also induced by a single 2-h exposure to radiation emitted at 0.9 GHz at non-thermal levels by a GSM telephone. This flax-based system is therefore well suited to studying the effects of low intensity stimuli, including those of electromagnetic radiation. To begin to determine the underlying mechanisms, in which calcium is implicated, it is desirable to analyse the changes in ions in the tissues affected. We therefore performed a Secondary Ion Mass Spectrometry (SIMS) study of the 611 distribution of the main inorganic cations in the hypocotyl of control and calcium-deprived seedlings. This showed decreases in calcium, sodium and potassium and an increase in magnesium that did not alter substantially the overall ratio of divalent to monovalent cations.

As reliance of responses to epidemiological questionnaires on atopic symptoms is doubtful, we studied the predictive value of these questions relative to atopy, defined by the presence of serum specific IgE, taking into account some extraneous variables such as age and sex. The study population included 2067 adults, 20-60 years old. The protocol consisted of a standardized questionnaire and an evaluation of serum specific IgE using the Phadiatop (Pharmacia Diagnostics, Uppsala, Sweden) test. The predictive value of each symptom suggestive of atopy was quite low, but was much dependent on age and sex. Women more often than men reported atopic symptoms in the absence of atopy. Similarly, the predictive value of each symptom decreased with age. Thus atopic symptoms do not have the same value as predictors of atopy. These findings have both clinical and epidemiological important implications.

Exposing seedlings of the flax, Linum usitatissimum L., to a variety of weak environmental stresses followed by a 2 day calcium deprivation, triggers the common response of production of epidermal meristems (actively dividing groups of cells) in the hypocotyl, which is the part of the stem between the root and the cotyledons (the pre-existing leaves in the embryo). This production reaches a plateau of 10-20 meristems after a month in the case of mechanical stimulation and cold shock. Recently, we have shown that radiation from a global system for mobile communication (GSM) telephone also triggers production of meristems with a plateau of around six meristems. Here, we show that a single 2 h exposure to radiation emitted at 105 GHz at non-thermal levels by a Gunn oscillator induces meristem production with kinetics similar to that induced by weak environmental stimuli and radiation from GSM telephone. Bioelectromagnetics 00: 1-5, 2003. ß 2003 Key words: environmental stress; microwaves; flax; meristem; calcium INTRODUCTION Plants are exposed to a variety of natural abiotic and biotic stresses, such as drought, rain, thermal stresses, wind, mechanical contact, pricking by insects, wounds inflicted by phytophages, and infection by pathogens. These stresses generate intracellular signals [Braam and Davis, 1990;Braam et al., 1996;Jonak et al., 1996; Mizoguchi et al., 1997; Meskiene and Hirt, 2000], such as calcium transients [Knight et al., 1991[Knight et al., , 1992[Knight et al., , 1996 Takahashi et al., 1992; Malhó et al., 1998; Plieth et al., 1998; Mithöfer et al., 1999], that lead to modifications of growth rate and/or morphogenesis of the whole plant [Adams, 1924;Jaffe, 1985; Thellier et al., 2000].Our group has developed an experimental system that clearly reveals the effects of environmental stimuli [Verdus et al., 1996[Verdus et al., , 1997. In this system, week-old seedlings of the flax Linum usitatissimum L. var Ariane are subjected to a temporary (typically 2 days) calcium deprivation by replacing the complete growth medium with a calcium-depleted medium. After this depletion the plants are again grown on the complete medium. This results in the production of epidermal meristems in the hypocotyls, typically 10-20 meristems after a month, provided the seedlings have previously undergone an exposure to different stresses or stimuli, such as drought or touch, respectively. In plants, meristems are small groups of actively dividing cells that after differentiation ultimately produce stem or root tissues.The hypocotyl is the part of the stem located between the root and the cotyledons (pre-existing leaves in the embryo). In control experiments designed to minimize these stresses, the mean number of meristems produced per plant is 0 or 1 after subjecting the plants to calcium deprivation.Recent experiments have shown that exposure to radiation emitted from a global system for mobile communication (GSM) telephone followed by calcium deprivation, leads to meristem production in our flax system [Tafforeau et ...