Linked Life Data

7648436

Source:http://linkedlifedata.com/resource/pubmed/id/7648436

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1995-9-28
pubmed:abstractText
The mechanism by which tumor necrosis factor (TNF) induces cytotoxicity of murine fibroblasts was investigated. Electrophoresis of DNA extracted from TNF-treated L929 targets showed fragmentation of DNA into a ladder-like pattern, typical of cells dying by apoptosis. Morphologic analysis also indicated apoptotic cell death, demonstrating clumping and crescentic condensation of chromatin. In contrast, chromatin condensation and ladder-like DNA fragmentation were not detected in L929 targets dying by necrosis from exposure to heat, repeated cycles of freeze-thaw, and sodium azide. Chromatin condensation was an early event, detected as early as 6 h of incubation. However, DNA fragmentation (assayed by double-stranded fragmentation assay and gel electrophoresis), as well as the apoptotic changes detected by Hoechst fluorescence, both occurred later and did not precede TNF cytotoxicity (membrane permeabilization detected by trypan blue or propidium iodide staining). This atypical pattern of apoptosis was a characteristic of L929 target cells rather than a generalized cytotoxic response to TNF because TNF-treated squamous cancer cells showed typical features of apoptosis (DNA fragmentation before cytotoxicity) and etoposide-treated L929 cells demonstrated the same atypical kinetics as TNF-treated cells. Zinc significantly inhibited TNF cytotoxicity as well as DNA fragmentation of L929. However, because DNA fragmentation occurred belatedly in TNF-treated targets, lagging behind cytotoxicity, the protection by zinc against TNF appears mediated by events that occur before the ultimate endonuclease-induced cleavage of DNA into small fragments.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
1079-9907
pubmed:author
pubmed:issnType
Print
pubmed:volume
15
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
71-80
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Atypical apoptotic cell death induced in L929 targets by exposure to tumor necrosis factor.
pubmed:affiliation
Department of Medicine, Veterans Administration Wadsworth-University of California, Los Angeles Medical Center 90073, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S.