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Biomedical subjects

J Lister-James

Publications and source records attributed to J Lister-James.

24 records · Page 2Linked to original sources
PubMed1986

Effect of reperfusion and hyperemia on the myocardial distribution of technetium-99m t-butylisonitrile.

Technetium-99m t-butylisonitrile ([99mTc]TBI) is a promising new radiotracer for myocardial imaging. Its myocardial uptake is sufficiently high in humans to permit planar, tomographic, and gated images of excellent technical quality. We studied the behavior of [99mTc]TBI in the dog at rest and under conditions of hyperemia and reperfusion in order to determine the relationship between [99mTc]TBI myocardial concentration and blood flow. After permanent occlusion of the left anterior descending artery, the correlation between the relative myocardial concentration of [99mTc]TBI and regional myocardial blood flow (RMBF) measured with radiolabeled microspheres was excellent. In a dog model of transient hyperemia, the concentration of [99mTc]TBI was directly related to blood flow but underestimated the degree of hyperemia. Technetium-99m TBI redistributed into transiently ischemic myocardium. The myocardial concentrations of [99mTc]TBI and thallium-201(201TI) in transiently ischemic myocardium were similar at 10 and 30 min following reperfusion and were significantly higher than blood flow prior to reperfusion. When [99mTc]TBI was injected into the left anterior descending artery, the washout was slow, falling to 78% of initial activity at 120 min after injection. In conclusion, [99mTc]TBI reflects regional myocardial blood flow accurately in ischemic and normal resting myocardium and underestimates blood flow at high flows. The rate of myocardial redistribution after reperfusion is similar for [99mTc]TBI and 201TI.

Animals↗
PubMed1984

A new Tc-99m-labeled myocardial imaging agent, hexakis(t-butylisonitrile)-technetium(I) [Tc-99m TBI]: initial experience in the human.

The cationic complex Tc-99m hexakis(t-butylisonitrile)technetium(I) (TBI) has been shown to concentrate in the myocardial tissue of several animal species. In the present preliminary study, the biodistribution of this material was examined in four normal subjects and in two patients with coronary artery disease. In three normal humans injected at rest, planar, tomographic, and gated myocardial images of high technical quality were obtained between 1 and 4 hr after injection. In one subject studied both at rest and during maximal exercise, the lung and heart activities were similar, whereas the liver-to-heart activity ratio was 3:1 at 60 min at rest compared with 1.8:1 with maximal exercise. In two patients with coronary artery disease, transient ischemia appeared as a perfusion defect up to 4 hr after injection at maximal exercise, and the image appeared normal when Tc-99m TBI was administered at rest. The images of areas of infarction appeared abnormal after injection at rest and after injection during exercise. Technetium-99m TBI is a promising myocardial imaging agent that may permit high-quality planar, gated, and tomographic imaging of myocardial ischemia and infarction.

Coronary Disease↗
PubMed1984

I-123 HIPDM brain imaging with a rotating gamma camera and slant-hole collimator.

The performance of a slant-hole collimator was compared with that of a standard straight-bore, low-energy collimator for tomographic imaging of I-123-iodinated amine brain agents. Improved in-slice resolution was due to the greater proximity between collimator and the subjects' heads. We conclude that high quality tomographic images of the brain can be obtained from rotating cameras equipped with slant-hole collimators.

Brain↗
PubMed1984

A comparison of two cerebral perfusion tracers, N-isopropyl I-123 p-iodoamphetamine and I-123 HIPDM, in the human.

Both N-isopropyl I-123 p-iodoamphetamine (IMP) and I-123 HIPDM have been advocated as radiotracers for assessing regional cerebral perfusion. We compared the biodistribution of the two tracers in 19 patients without evidence of neurological disease. Following intravenous injection, both tracers accumulated initially in the lung. Early after injection the fraction of the total brain uptake was higher for I-123 HIPDM than for I-123 IMP. The peak brain activity for I-123 IMP was higher than for I-123 HIPDM . Brain activity was unchanged with both tracers between 30 and 60 min after injection. Tomographic images were similar in appearance for both tracers. No eye uptake greater than background was observed with either tracer in any patient at 2, 24, and 48 hr. I-123 IMP is superior for tomographic imaging because of its higher brain uptake, whereas I-123 HIPDM may be superior for studies performed during rapid changes in blood flow.

Amphetamines↗
PubMedDate not supplied

Enhanced kidney clearance with an ester-linked 99mTc-radiolabeled antibody Fab'-chelator conjugate.

Bifunctional chelators for labeling antibodies with 99mTc based on the N3S core of (mercaptoacetyl)-triglycine having ester or amide linking moieties were synthesized and site-specifically attached to the sulfhydryl groups of the Fab' fragment of antimyosin. Protein labeling was quantitative after 15 min; postlabeling purification was not necessary. The radiolabeled conjugates exhibited no loss of immunoreactivity. Under basic conditions, the ester-linked conjugate lost 95% of the radiolabel in the form of the 99mTc complex of (mercaptoacetyl)triglycine as determined by RP-HPLC, while the radioactivity in the amide-linked conjugate remained completely bound to the protein. In a mouse biodistribution study, the ester-linked conjugate showed a 2-fold enhancement in clearance from the kidney when compared to the amide-linked product.

Amides↗