[Measles-Mumps-Rubella vaccination of an egg-allergic child sensitized to gelatin]. / Bonne tolérance de la vaccination rougeole-oreillons-rubéole chez un enfant allergique à l'œuf et sensibilisé à la gélatine.

The Measles-Mumps-Rubella (MMR) vaccine is often postponed in egg-allergic patients due to fear of anaphylactic reaction at the time of injection of this vaccin produced on egg derivates. However, this vaccine is recommended by health authorities, especially in case of increased measles incidence, and international recommendations indicate that there is no need for predictive allergological work-up and that the MMR vaccine is well tolerated in egg-allergic patients. We report on the case of a 12-year-old child with severe immediate-type egg allergy. Immediate-reading intradermal skin tests performed prior to the MMR vaccine were positive. Subsequent allergological work-up revealed a gelatin sensitization, and the child tolerated injections of the vaccine given according to a tolerance induction protocol. Gelatin is used as a stabilizer in numerous vaccines and may be responsible for immediate-type hypersentivity reactions to gelatin-containing vaccines. In case of reaction induced by the MMR vaccine, one needs to explore a potential gelatin sensitization/allergy. The MMR vaccine should be given and is well tolerated in patients with immediate-type egg hypersensitivity, even when gelatin sensitization is combined.

The 24-h rhythm of metabolic activity of the cockroach circadian pacemaker.

In the cockroach, Leucophaea maderae, the optic lobes contain a circadian pacemaker. The metabolic activity of optic lobe neuropils was measured at 17 time points over a 24-h period in constant darkness, using cytochrome oxidase activity as functional marker. The results revealed a clear 24-h energy metabolism rhythm in neuropils and particularly in the lobula plate, a part of the region which is assumed to include a circadian pacemaker in this species.

Diet-dependent switch from circadian to hourglass-like operation of an insect photoperiodic clock.

The results of resonance experiments gave evidence that circadian organization was involved in photoperiodic diapause induction of Pieris brassicae. However, giving the larvae an artificial diet instead of the host plant deeply altered the resonance effect and led to a response that could be accounted for by the operation of a noncircadian timer (hourglass). This important change, however, had no effect on the insect's ability to discriminate between short- and long-day 24-hr cycles. Thus, it is possible via the metabolism to switch the photoperiodic mechanism to a circadian or an hourglass-like mode of operation without impairing the photoperiodic time measurement.

[Thermoperiodic information and the induction of diapause in Pieris brassicae L]. / L'information thermopériodique et l'induction de la diapause chez Pieris brassicae L.

When exposed their whole larval life to a 24 h. thermoperiodic cycle in constant darkness, individuals of Pieris brassicae L. give diapausing or non-diapausing pupae according to the length of the cold and warm sequences. The curve of thermoperiodic induction is similar to the photoperiodic curve.