Occlusion of the circumflex coronary artery induced a profound redistribution in ischemic rabbit myocardium of several lysosomal acid hydrolases, including cathepsin D, B-acetylglycosaminidase, and acid phosphatase. 30-45 min after ligation non-sedimentable cathepsin D activity rose from 36% of the total activity to 42-48%, and in immunohistochemical preparations cathepsin D appeared to have diffused from lysosomes into the cytosol of injured cells. A pharmacologic dose of methylprednisolone (50mg/kg) significantly delayed the subcellular redistribution of cathepsin D and the other hydrolases in ischemic heart. Thus, in treated hearts the nonsedimentable activity of cathepsin D rose to only 38% after 30 min of ischemia and 42% after 45 min (P is less than 0.05 compared to untreated ischemia at each time). Similarly, unlike untreated hearts, noevidence of enzyme diffusion from lysosomes could be demonstrated immunohistochemically in corticosteroid-treated ischemic hearts for over 45 min. After 1-2 h of ischemia, however, steroid-protected myocytes deteriorated and the biochemical activity and anatomical distribution of cathepsin D were indistinguishable from untreated ischemic hearts. This study demonstrates that corticosteroid pretreatment does not prevent alterations in cardiac lysosomes during severe ischemia indefinitely, but does delay their development significantly.
R S Decher, A R Poole, J T Dingle, K Wildenthal
Usage data is cumulative from May 2024 through May 2025.
Usage | JCI | PMC |
---|---|---|
Text version | 109 | 0 |
41 | 8 | |
Figure | 0 | 3 |
Scanned page | 260 | 6 |
Citation downloads | 46 | 0 |
Totals | 456 | 17 |
Total Views | 473 |
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.