Lung morphology after late fetal tracheal ligation in rats.

Pulmonary hypoplasia and persistent pulmonary hypertension are the main causes of mortality and morbidity in congenital diaphragmatic hernia (CDH). Prenatal tracheal occlusion accelerates lung growth, but the mechanism remains unknown. In order to be able to establish the accuracy of our experimental model for further molecular biological examinations, we evaluated the histologic structure of 1. fetal lungs subjected to tracheal occlusion compared to 2. normal fetal lungs, 3. hypoplastic lungs in CDH, and 4. normal neonatal lungs. One group of Sprague-Dawley rat fetuses were subjected to intrauterine tracheal ligation (TL) on gestational day 19 (n = 7). Control fetuses were obtained from the same litters as those subjected to TL (n = 8). Another group of pregnant Sprague-Dawley rats were given 100 mg nitrofen on gestational day 9.5 to create CDH (n = 8). All fetuses were delivered by cesarean section on day 21. Lungs from 1-day-old, healthy, non-operated, newborn Sprague-Dawley rats were also examined (n = 6). Lung weight to body weight ratio was significantly higher in the TL lungs (5.0 +/- 0.36 %), compared to control lungs (2.8 +/- 0.15 %), CDH lungs (1.9 +/- 0.12 %), and normal neonatal lungs (4.2 +/- 0.18 %). Volume density of alveolar air space and radial alveolar count (RAC) in TL lungs (52 +/- 1.4 %) (3.3 +/- 0.25) were significantly higher than in control lungs (34 +/- 3.4 %) (2.2 +/- 0.17) and in CDH lungs (16 +/- 1.7 %) (1.7 +/- 0.07). No significant differences were found between the TL and the normal neonatal group (59 +/- 1.4 %) (3.6 +/- 0.11). Fetal lungs after TL showed evidence of growth stimulation with increased volume density of alveolar air space and increased RAC, comparable to findings in normal neonatal lungs.

Appendicitis in children--impact of US and CT on the negative appendectomy rate.

BACKGROUND/PURPOSE: Ultrasonography (US) and computed tomography (CT) have proved useful for the evaluation of suspected appendicitis and were introduced as diagnostic tools at our institution about ten and five years ago, respectively. The aim of this study was to evaluate how the negative appendectomy and perforation rates have changed with increased use of US and CT. METHODS: The medical records of 600 children who underwent appendectomy during years 1991, 1994, 1997, and 2000 were reviewed. Perforation in perforated appendicitis was considered to have occurred after admission if the time interval between the first health professional contact and surgery exceeded 12 hours. RESULTS: The total number of appendectomies during the years 1991, 1994, 1997, and 2000 was 406, 334, 407, and 397, respectively. The negative appendectomy rate for the same years was 23%, 8.7%, 8.0%, and 4.0%, respectively. The overall rate of perforations and the perforation rate after admission was 32% and 12%, 34% and 7.3%, 34% and 13%, and 29% and 2.1%, respectively. The rate of patients who underwent US and CT during each period was 1.0% and 0.0%, 41% and 0.0%, 91% and 21% and 98% and 59%, respectively. CONCLUSIONS: The negative appendectomy rate has been substantially reduced after the introduction of both US and CT. The rate of perforation after admission has not increased.