Measuring lung function in infancy.

Although the earliest reliable lung function tests in infants were performed as long as 40 years ago, there has only recently been a growth in this area, as simpler methods and better equipment and IT resources have been developed. Exciting information is accumulating about the normal physiology and pathology of the infant lung. Many basic questions are still unanswered and the ability to perform these tests remains confined to a few specialized centres. To co-ordinate the development of ILFT and establish standardization in a number of areas including measurement conditions, equipment specifications, methodology protocols and data analysis, international collaboration is necessary between the teams working in this field (Table 5). Collaborative groups are currently addressing these issues and are also developing recommendations regarding the design of randomized clinical trials, multi-centre studies and research agendas. Infant lung function testing remains primarily a research tool. Our aim should be not only to refine and develop the techniques of physiological measurement but to apply ILFT to the objective study of respiratory illness in infants in the clinical setting so as to aid in the prevention and treatment of these common, debilitating and costly diseases.

Measuring pulmonary function in infancy.

In recent years there has been a growing interest in the measurement of pulmonary function in infants for both clinical and research purposes. Such measurements remain limited by the complexity of the equipment as well as by the technical and physiological challenges of testing infants and neonates. Despite these problems, assessment of respiratory function in early life provides exciting information about the post-natal growth and development of lungs in health and disease. The aim of this paper is to discuss the physiological, technical and ethical problems surrounding these procedures, as well as reviewing the current methods of testing pulmonary function in the very young. Consideration is given to the developments needed if infant pulmonary function tests are to realise fully, their potential as research and clinical tools.

Effect of centrally administered oxytocin on the association between cortical electroencephalogram and milk ejection in the rat.

Abstract The milk-ejection reflex of the rat is closely associated with synchronized activity of the cortical electroencephalogram (EEG), and the frequency of milk ejections has been shown to be greatly facilitated by central oxytocin. The following experiments were undertaken to examine the changes in the EEG during facilitation of the reflex by central oxytocin. Intracerebroventricular injection of 1 mU (2.2 ng) oxytocin during suckling caused a rapid increase in the frequency of milk ejections but no change in the predominantly synchronized pattern of the EEG. However, after a delay (11.3 +/- 0.8 min, mean +/- SE) there appeared to be an increasing proportion of desynchronization, which correlated with cessation of the facilitated milk-ejection responses. Hence, the observed EEG desynchronization may signal activation of mechanisms inhibitory to the milk-ejection reflex. In the absence of the suckling stimulus oxytocin also caused a change to desynchronization. However, this effect was more pronounced and commenced after a much shorter latency (1.7 +/- 0.4 min, mean +/- SE; P < 1.001), suggesting that the desynchronizing effect of oxytocin on the EEG can be attenuated by the suckling stimulus. These results demonstrate two phases in the action of central oxytocin in the suckled rat. During the initial phase, the milk-ejection reflex is facilitated and although there may be a concomitant desynchronizing influence on the EEG this is prevented by the influence of the suckling stimulus. In the later phase, this desynchronizing influence predominates and is accompanied by cessation of milk-ejection responses. Although milk ejections were generally restricted to periods of a synchronized EEG as previously reported, during the oxytocin-induced change to desynchronization a number of milk ejections were observed to occur in the absence of a synchronized EEG. These results provide further evidence that the association between milk ejection and the EEG state is not an absolute causal relationship.