Linked Life Data

9176178

Source:http://linkedlifedata.com/resource/pubmed/id/9176178

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5 Pt 1
pubmed:dateCreated
1997-7-8
pubmed:abstractText
Previous studies on human colorectal tumor protein synthesis in situ relied on techniques that required intra- or perioperative sampling to obtain a sufficient biopsy size. The purpose of the present study was to develop a new technique by use of new mass spectrometry equipment [capillary gas chromatography (GC)-combustion isotope ratio mass spectrometry (IRMS)], which allows reduction of the necessary sampling size. Thereby, tumor sampling could be done via conventional rectosigmoidoscopy, excluding the need for further disturbing invasive measures. Fifteen postabsorptive patients with localized rectal cancer received a primed-constant infusion of [1-13C]leucine (0.16 mumol.kg-1.min-1 constant, 9.6 mumol/kg prime). Forceps biopsies were taken after 3 and 6 h. In five subjects, tumor tissue and normal mucosa were studied simultaneously. Determination of protein-bound leucine enrichment was done by GC-IRMS, and GC-quadrupole MS was used to determine tracer-to-tracee ratios (tracer/tracee) for free intracellular leucine. GC-MS data demonstrated achievement of a steady state in the precursor pool enrichment after 3 h of isotope infusion (tracer/tracee at 3 h: 6.34 +/- 0.46%, at 6 h: 6.58 +/- 0.38%). Calculation of tumor protein synthesis yielded a fractional synthetic rate (FSR) of 1.06 +/- 0.11%/h or 25.5 +/- 2.6%/day (range 12.0-37.1%/day). At any time, protein-bound leucine enrichment was significantly higher in tumor tissue than in normal mucosa of the same subject. However, protein synthetic rates were comparable (tumor: 1.09 +/- 0.20%/h, mucosa: 1.29 +/- 0.28%/h). Thus combined GC-combustion IRMS and GC-/quadrupole MS provide a simple, reliable, and minimally invasive method to determine tumor FSR in situ, thereby excluding interferences common to previous methods. Tumor and mucosa tissues are similar with respect to protein synthesis, but they apparently differ with respect to leucine extraction from the arterial blood.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0002-9513
pubmed:author
pubmed:issnType
Print
pubmed:volume
272
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
E796-802
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1997
pubmed:articleTitle
Determination of protein synthesis in human rectal cancer in situ by continuous [1-13C]leucine infusion.
pubmed:affiliation
Department of Surgery, Klinikum Grosshadern, Munich, Germany.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't