Amino acid analysis of human fetal lung elastin was undertaken in 49 instances of live-born neonates, ranging from 380 g to full term, and in 3 abortuses of 12-14 wk gestation. The data suggest that formation of the cross-linking agents, desmosine and isodesmosine, occurs early, between 14 and 22 wk. The ratio of neutral to charged amino acids remains low until the 36th wk when it attains adult levels. The composition of elastin was independent of sex and duration of survival. In three neonatal pulmonary diseases (respiratory distress syndrome, atelectasis, and hemorrhage) ratios were significantly lower than those found in nondiseased lungs. This may be a reflection of immaturity or may be a predisposing factor in neonatal lung disease. The latter hypothesis is attractive and receives indirect support from the association of a more polar elastin with other diseases, including adult emphysema and atheromatous aortic change.
Hugh E. Evans, Stephen Keller, Ines Mandl
Usage data is cumulative from December 2023 through December 2024.
Usage | JCI | PMC |
---|---|---|
Text version | 119 | 0 |
73 | 18 | |
Scanned page | 183 | 3 |
Citation downloads | 46 | 0 |
Totals | 421 | 21 |
Total Views | 442 |
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.