Linked Life Data

1574575

Source:http://linkedlifedata.com/resource/pubmed/id/1574575

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1992-6-1
pubmed:abstractText
A series of thiols having net charge (Z) varying from -2 to +3 were studied using aerobic suspensions of Chinese hamster V79-171 cells in pH 7.4 medium at 297 K to evaluate the rate of uptake by cells and the extent of radioprotection as a function of thiol concentration in cells. For measurement of cellular levels, cells were separated from medium by centrifugation through silicone oil and tritiated water was employed to determine cell water volume. Estimated half-lives for uptake were: 2-mercaptosuccinate (Z = -2), greater than or equal to 1 h; 3-mercaptopropanoate (MPA, Z = -1), less than 2 min; 2-mercaptoethanol (2ME, Z = 0), less than 2 min; cysteamine (CyA, Z = +1), less than 2 min; N-(2-mercaptoethyl)-1,3-diaminopropane (WR-1065, Z approximately +2), approximately 40 min; N1-(2-mercaptoethyl)spermidine (WR-35980, Z approximately +3), greater than or equal to 10 h. After equilibration the cellular concentration of MPA was 60 +/- 8% of the medium level; the corresponding values for 2ME and CyA were 95 +/- 3 and 180 +/- 12%, respectively, but equilibrium was not reached for the other thiols studied. Those thiols taken up at significant rates were evaluated in terms of their ability to protect against aerobic gamma-ray-induced lethality. The results, summarized in terms of the cellular concentration of thiol (mmol dm-3) needed to achieve an aerobic radioprotection factor of 1.5, were as follows: MPA, 80 +/- 15; 2ME, 24 +/- 2; CyA, 4.7 +/- 1.3; WR-1065, 3.4 +/- 0.6. These values accorded well with those predicted from hydroxyl radical scavenging and DNA radical repair rates obtained using pBR322 DNA as a model system. This shows that hydroxyl radical scavenging and DNA radical repair are important mechanisms in the protection of cells by thiols and that the net charge on the thiol is a significant factor in its effectiveness. The results indicate that in air hydroxyl radical scavenging is the dominant mode of action by MPA, but that chemical repair of DNA radicals becomes significant for 2ME and is the dominant mechanism of protection for CyA and WR-1065.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0033-7587
pubmed:author
pubmed:issnType
Print
pubmed:volume
130
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
194-204
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Thiol uptake by Chinese hamster V79 cells and aerobic radioprotection as a function of the net charge on the thiol.
pubmed:affiliation
Department of Radiology, University of California, San Diego, La Jolla 92093.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.