These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Tracer mixing: sites of tracer infusion and sampling.
    Author: Wisneski JA, Stanley WC, Neese RA, Morris DL, Brooks GA, Gertz EW.
    Journal: Horm Metab Res; 1990 Mar; 22(3):157-62. PubMed ID: 2344994.
    Abstract:
    Controversy exists in the literature concerning the correct infusion and sampling sites in studies measuring substrate turnover rates. To investigate this problem, we examined the results obtained with various infusion and sampling sites in 7 anesthetized dogs. [1-14C]lactate was infused by a primed continuous infusion method in three different sites (the left ventricle, ascending aorta, and the aortic arch) in a sequential fashion; samples were obtained simultaneously from five sites (femoral artery, carotid artery, pulmonary artery, superior vena cava and inferior vena cava) for each of the three different infusion sites. [U-13C]lactate was also infused in a femoral vein and simultaneous samples were obtained in the carotid artery and femoral artery for analysis of the stable isotope. [14C]lactate analysis demonstrated that infusion of the tracer into the left ventricular chamber resulted in a uniform distribution in the systemic circulation. Infusion into the ascending aorta near the aortic valve resulted in uniform distribution of tracer in four out of five experiments. Tracer infusion into the aortic arch resulted in nonuniform systemic distribution of tracer. The [U-13C]lactate results showed that infusion into the femoral vein gives uniform systemic distribution, similar to that observed with left ventricular infusion. The pulmonary artery lactate specific activities varied from those in the superior vena cava. Thus, this study shows that the tracer must be infused in the left ventricle or upstream from this chamber to obtain optimal systemic distribution. Vena caval sampling, especially superior vena caval sampling, will not give a consistent mixed venous concentration of the lactate tracer. Therefore, aortic tracer infusion with vena caval sampling may lead to errors in determining substrate turnover values.
    [Abstract] [Full Text] [Related] [New Search]