Pediatric research
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Estradiol-producing ovarian cysts were found in four very preterm females at a postconceptional age that slightly preceded the expected time of delivery. The serum concentration of estradiol was very high. In the first infant one cystic ovary was removed surgically. ⋯ In infants 3 and 4 the cysts disappeared and the serum estradiol normalized spontaneously. Measurements of serum concentrations of luteinizing hormone and follicle-stimulating hormone before and after an iv injection of luteinizing hormone releasing hormone showed that preterm girls with early estradiol-producing ovarian cysts have a postpubertal type of response to luteinizing hormone-releasing hormone. When the test is repeated some months later they have a prepubertal type of response, which is normal for their age.
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Lobar atelectasis is common among infants and children with obstructive lung diseases. However, the effect of lobar collapse in the presence of diffuse lung disease on gas exchange in the pediatric age group has not been described. We developed an infant model of lobar atelectasis using piglets and tested the hypothesis that diffuse alveolar hypoxia increases shunt fraction (Qs/QT) associated with lobar atelectasis by redirecting pulmonary blood from the well-ventilated portion of the lung into the collapsed region. ⋯ The percentage of cardiac output perfusing the left lower lobe fell by an average of 70 +/- 17% in response to lobar collapse. When animals were ventilated with 12% oxygen, shunt fraction increased to 18.7 +/- 7.1% and blood flow to the collapsed left lower lobe increased from 9 +/- 3 to 22 +/- 3% of cardiac output. Lobar atelectasis in conditions where diffuse alveolar hypoxia is present may be associated with a significantly greater intrapulmonary shunt than lobar atelectasis in children with otherwise normal lungs.