Biomedical subjects

F Turner

Publications and source records attributed to F Turner.

10 recordsLinked to original sources

PubMed1992

Importance of precise determination of technetium-labeled DISIDA concentrations for in vitro hepatocellular transport studies.

Technetium 99m-labeled diisopropyliminodiacetic (acid [99mTc]DISIDA) has been used extensively in the evaluation of hepatobiliary diseases. As a result of investigation into transport mechanisms of [99mTc]DISIDA, we undertook to determine precise concentrations of this compound in the standard clinical formulation. Calculations based on published formulas were used. These take into account column efficiency, the time since the previous elution of 99mTc from the 99Mo column, and the total quantity of 99mTc eluted. Primary cultures of rat hepatocytes were used to evaluate the transport of Na99mTcO4 and the 99mTc-labeled DISIDA monomer. Pertechnetate was not taken up by the hepatocytes, the amount of [99mTc]DISIDa taken up was not dependent on the concentration of DISIDA but rather on the concentration of technetium, when the DISIDA/99mTc ratio was varied in the culture medium. We conclude that calculation of the total technetium concentration is necessary to determine the amount of compound taken up by the liver, and to interpret kinetic studies of hepatocellular transport mechanisms.

Animals↗

PubMed1983

Quantitative biliary dynamics: introduction of a new noninvasive scintigraphic technique.

We used a Tc-99m-labeled hepatobiliary agent to measure the partition of hepatic bile between gallbladder and intestine in sixteen normal patients and nine patients with cholelithiasis. In normal subjects, the fractions of the hepatic bile that flow into the gallbladder and the small intestine were widely variable, with mean values of 69 +/- 7% (s.e.) and 31 +/- 7% respectively. Bile reflux into the common hepatic duct was rare, occurring during the first 2/3 of the gallbladder ejection period and only when the ejection fraction was greater than 59%. The gallbladder's mean latent period, ejection period, ejection fraction, and ejection rate were 2 +/- 1 min, 11 +/- 1 min, 59 +/- 4%, and 5.9%/min respectively. In patients with cholelithiasis, the fraction of hepatic bile flowing into the gallbladder was normal, but the ejection fraction was significantly reduced (p less than 0.005). For an equivalent dose of cholecystokinin, the gallbladder in cholelithiasis is less responsive than in normal subjects.

Adult↗

PubMed1982

Measurement of gallbladder emptying sequentially using a single dose of 99mTc-labeled hepatobiliary agent.

The gallbladder emptying response to a single large (20 ng/kg) and four equally divided sequential small (5 ng/kg each) doses of octapeptide of cholecystokinin at 20-min intervals was measured in a paired study in six normal subjects noninvasively and quantitatively by a nongeometric method using a gamma camera, computer, and 99mTc-labeled hepatobiliary agent. The gallbladder mean (+/- SD) ejection fraction after a single large dose (20 ng/kg) of octapeptide of cholecystokinin was 34 +/- 24% and after four sequential small (5 ng/kg each) doses was 42 +/- 14%, 45 +/- 28%, 37 +/- 22%, and 32 +/- 27%, respectively (p greater than 0.05). The results of this study indicate that the first part of the 5 ng/kg sequential octapeptide of cholecystokinin dose is as effective as the single 20-ng/kg dose. The gallbladder emptying requires continued presence of high levels of octapeptide of cholecystokinin in the serum closer to levels that initiate contraction and in the absence of which the gallbladder ceases to empty further despite the fact it has inherent capacity to do so. Each of four equal octapeptide of cholecystokinin doses given sequentially elicits, on the average, an equal degree of emptying response. The method has potential for application in the study of the pharmacological effects of drugs on the biliary dynamics using a single dose of 99mTc-labeled hepatobiliary radiopharmaceutical.

Adult↗

PubMed1978