STRUCTURAL CONSIDERATIONS

Any therapeutic treatment applied to a developing and/or growing organ ism is complicated by the fact that the treatment window may hit a cri tical stage of a developing organ. This means that unlike administrati on in adults, dosage and timing of drug applications are important iss ues because of their possible damaging effects. In view of the timing of lung developmental phases, it appears that perinatal interferences by diseases, environmental influences or drugs will affect specificall y alveolar development and microvascular maturation. Numerous publicat ions report, that the developing lung can be disturbed by a variety of factors, such as temperature, oxygen tension, cigarette smoke, malnut rition, drugs and hormones, in particular glucocorticoids. In well-doc umented animal experiments perinatal glucocorticoid treatment, even in very low doses, inhibited alveolization. This effect has been analyse d in more detail and a hypothesis for its mechanism has been presented . The above effects on lung development may be extremely difficult to assess in human infants by noninvasive techniques, The message, howeve r, remains that potent drugs should be used with great reservation.