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Biomedical subjects

B C Lentle

Publications and source records attributed to B C Lentle.

At least 37 records · Page 2Linked to original sources
PubMed1987

Gallium-67 scintigraphy and non-small-cell bronchogenic carcinoma: a quantitative in-vivo predictive assay?

Gallium-67 scintigraphy has been of limited use in detecting lung cancers and micrometastases. To study its potential for determining the aggressiveness of a cancer, we reviewed the charts of 44 patients with non-small-cell bronchogenic carcinoma who had not been receiving treatment when 67Ga scintigraphy was performed. The mean length of survival for the 18 patients with low or little uptake of the tracer, corrected for tumour size, was 19.7 months, and for the 26 with high uptake 9.4 months (p less than 0.01). Such in-vivo predictive assays may be a rational goal for tumour scintigraphy.

Carcinoma, Bronchogenic↗
PubMed1987

Biological behavior of 67Ga-citrate in New Zealand White rabbits.

The pharmacokinetics, protein binding, excretion and tissue distribution of 67Ga after the administration of 67Ga-citrate to New Zealand White rabbits is described. Data for 67Ga blood levels were best described by an equation with three exponential components exhibiting half lives of 0.25 h, 7.4 h and 19.5 h, with almost all of the activity in a protein bound form. Weekly urinary excretion (approximately 27%), possibly in a metabolized form, and fecal elimination (approximately 20%) were greater than the reported values in man, but there was a similar organ distribution pattern in these animals as in man. The overall biological handling was judged to be similar in both species making the rabbit a suitable model for further 67Ga-citrate studies in vivo.

Animals↗
PubMed1987

Detecting bone marrow metastases at the time of examining the liver with radiocolloid.

In a prospective study of 200 different consecutive patients with cancer, the bone marrow of the lumbar spine and pelvis has been examined at the time of obtaining a radiocolloid examination of liver and spleen. The images were examined "blind" by three observers who all agreed about the findings in 177 (89%) of the patients. Agreement by any two was considered to be definitive. The radiocolloid marrow examinations in this selected population had an accuracy of 0.97, sensitivity of 0.80, and specificity of 0.98 in diagnosing metastatic disease when validated by all other available evidence, or follow-up. Of the patients thus examined, 16 (8%) had abnormal marrow scan findings reflecting metastatic disease, eight (4%) at the time radiographs were normal, and two at the time bone scintigraphy was normal. Excluding patients with bowel cancer, in whom the detection rate was zero, 16 (12.4%) marrow examinations were abnormal. As a result we now obtain "saturated" images of the marrow incidental to radiocolloid examinations of the liver and spleen in patients with cancer other than that of the bowel.

Bone Marrow Diseases↗
PubMed1986

Immediate and delayed effects of cis-platinum treatment on the short term biodistribution of 67Ga-citrate in mice.

The co-administration of a single medium toxic dose (5 mg/kg) of the chemotherapeutic drug cis-platinum (cis-Pt) with 67Ga-citrate was found to have minimal effects on the 3 h tissue distribution of the radiopharmaceutical in mice. When the same drug dose was given at two day intervals preceding the co-administered dose, virtually all tissues accumulated 67Ga to a greater extent. The tissue distribution of radiolabeled cis-Pt supported the development of drug-induced renal dysfunction as the primary cause.

Animals↗
PubMed1986

Effect of cis-platinum treatment on 67Ga-citrate localization and elimination in rabbits.

The treatment of rabbits with a typical dosage schedule of the chemotherapeutic drug cis-platinum resulted in an increased whole body retention of 67Ga-citrate due to decreased urinary and fecal excretion. The biodistribution of the tracer was also affected with most tissues showing greater accumulation. These changes are primarily related to drug-induced renal dysfunction, but other factors may also be involved.

Animals↗
PubMed1986

Effect of cis-platinum on the protein binding and pharmacokinetics of 67Ga-citrate.

Cis-platinum, a widely used chemotherapeutic drug, and K2PtCl4, a related complex, were found to inhibit the in vitro protein binding of 67Ga to human transferrin in isolated solution but not to whole serum. Cis-platinum treatment of rabbits resulted in enhanced protein binding and delayed blood clearance of subsequently injected 67Ga-citrate. These effects are related to the toxicity of the drug in vivo.

Animals↗
PubMed1984

Single photon emission tomography of lungs imaged with 99mTc-labeled aerosol.

The use of single photon emission computed tomography (SPECT) and radiolabeled aerosols for lung scanning offers theoretical advantages over conventional gamma camera imaging. We verified the feasibility of using such a system to define particle deposition. First, in two dogs, we detected segments of the lung which had received fewer radiolabeled particles because of obstruction to the airway by a balloon or a lead shot. Second, by comparing axial computed tomography (CT) images to their SPECT counterparts, we were able to demonstrate the effectiveness of SPECT in delineating large thoracic structures such as major vessels and central airways. We feel that SPECT also provides excellent images for qualitative work. We then used SPECT to study aerosol deposition in 13 normal subjects and eight patients. We found that the normal subjects had uniform peripheral deposition, but the eight with abnormal lung function had patchy deposition. Furthermore, we found that regions of abnormal deposition not seen on conventional views could be delineated by tomography. We conclude that this technique will improve our understanding of aerosol deposition in humans by providing a three-dimensional visualization of the lungs and airways.

Aerosols↗
PubMed1984

Investigation of sacroiliac disease: comparative evaluation of radiological and radionuclide techniques.

An attempt has been made to improve diagnostic precision in a group of diseases associated with inflammation of the sacroiliac joints by using a 99mtechnetium stannous pyrophosphate bone scan. Inflammation of these joints is associated with osteoblastic activity and is reflected by an increase in the uptake of radionuclide, which can be precisely quantitated. The uptake was markedly above the range of normal in patients with active ankylosing spondylitis (AS), and also in a number of patients with possible AS, psoriasis, and Reiter's syndrome. However, patients with Grade 4 radiological changes of the sacroiliac joints frequently had normal scans. This technique may be useful in the early diagnosis of sacroiliitis, and the nosological implications of the changes in patients with Reiter's syndrome and psoriasis are of interest.

Humans↗
PubMed1983

Abnormal biodistribution of radiogallium in persons treated with phenytoin.

After incidentally observing a patient in whom abnormal uptake of gallium-67 citrate appeared to be explained by treatment with phenytoin, we have conducted a prospective study. Of sixteen persons with a seizure disorder treated with phenytoin, five (31%) had abnormal uptake of radiogallium either in the mediastinum, pulmonary hilum or both. Of nineteen historical control patients only one had such abnormal uptake. Phenytoin may thus cause the false-positive uptake of radiogallium in lymph nodes; this finding may also prove to have nosological importance in identifying patients at particular risk of the side-effects of this drug.

Drug Interactions↗