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Biomedical subjects

A Taylor

Publications and source records attributed to A Taylor.

At least 667 records · Page 37Linked to original sources
PubMed1985

The role of nuclear imaging in the management of the first total artificial heart recipient.

On December 2, 1982, a permanent total artificial heart was implanted into the chest of a 61-year-old man with a progressive and irreversible cardiomyopathy. During the ensuing four-month hospitalization, a number of nuclear medicine procedures were obtained to assist in patient management. These procedures included gated cardiac radionuclide ventriculography, an I-123 iodoamphetamine scan for cerebral perfusion, and In-111 labeled leukocyte imaging. These radionuclide studies demonstrate the advantages of being able to monitor physiologic changes noninvasively and illustrate a potential role for nuclear cardiology in managing patients with a total artificial heart.

Amphetamines↗
PubMed1985

Prolonged half-life following diuretic radionuclide urography as evidence of ureteral obstruction.

Diuretic radionuclide urography is an accurate technique for detecting obstruction as a possible cause of nephroureteral dilatation. This technique was used to evaluate radioisotope retention in the renal pelvis noted on the bone scan of a patient with prostate carcinoma. There was some washout of the pelvic radioactivity following intravenous furosemide, but the half-life was markedly prolonged, allowing the correct diagnosis of partial obstruction to be made.

Aged↗
PubMed1985

Utility of bladder lavage in Meckel's scanning.

Accumulation of radioactive urine in a bladder diverticulum on a Tc-99m pertechnetate scan simulated uptake in a Meckel's diverticulum. The abnormal activity was present even following bladder catheterization and drainage. However, saline lavage washed the residual activity out of the bladder, and prevented a false-positive diagnosis. In addition to preventing false-positive studies, bladder lavage may increase the sensitivity of the test by allowing the detection of Meckel's diverticuli that are obscured by residual bladder activity.

Diagnosis, Differential↗
PubMed1985

The clearance of Xenon-133 following its parenchymal injection: a rapid method for estimating functional liver blood-flow.

Portal venous flow, total hepatic blood-flow and hepatic artery flow were measured in healthy dogs by electromagnetic flowmetry and a double indicator dilution technique. Functional liver blood-flow was measured by the double indicator dilution technique. Functional hepatic blood-flow did not correlate with portal venous flow, total hepatic blood-flow or hepatic artery flow, measured by either electromagnetic flowmetry or a double indicator dilution technique. There was a good correlation (r = 0.83, P less than 0.001) between functional hepatic blood-flow and liver blood-flow, measured by the clearance of Xenon-133 injected directly into the liver parenchyma. It is concluded that the clearance of Xenon-133, injected directly into the liver parenchyma, is a rapid and simple method for measuring functional hepatic blood-flow.

Animals↗
PubMed1985

Antibiotic activity of an isocyanide metabolite of Trichoderma hamatum against rumen bacteria.

A metabolite of Trichoderma hamatum, 3-(3-isocyanocyclopent-2-enylidene)propionic acid, was tested for its effects on growth of and carbohydrate metabolism in 11 strains of functionally important rumen bacteria. To standardize the biological activity of this unstable metabolite, a rapid, aerobic disc diffusion assay was developed using Escherichia coli ATCC 11775. In an anaerobic broth dilution assay using a medium lacking rumen fluid and containing a soluble carbohydrate, the minimum inhibitory concentration of the metabolite which completely inhibited growth of the rumen bacteria for 18 h at 39 degrees C was generally less than 10 micrograms X mL-1; however, the minimum inhibitory concentrations for Megasphaera elsdenii B159 and Streptococcus bovis Pe(1)8 were 10-25 and 25-64 micrograms X mL-1, respectively. In general, the Gram-negative strains were more sensitive than the Gram positive. The minimum inhibitory concentration for Bacteroides ruminicola 23 grown with glucose was 1 micrograms X mL-1; for B. ruminicola GA33 (glucose), B. succinogenes S85 (cellobiose), and Succinivibrio dextrinosolvens 24 (maltose), it was 2 microgram X mL-1. When added to a cellulose-containing rumen fluid medium, 1-4 micrograms X mL-1 of the metabolite delayed cellulose hydrolysis by B. succinogenes S85, Ruminococcus albus 7, and R. flavefaciens FD1 for up to 4 days, and 6-7 micrograms X mL-1 prevented hydrolysis for at least 1 month. In the presence of the metabolite, the proportion of acetate produced from soluble carbohydrate by the majority of strains increased, but with some strains net production of acetate decreased relative to production of other acidic fermentation products.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Anion transport inhibitors: effects on water and sodium transport in the toad urinary bladder.

Acidification of the medium bathing the serosal surface of the toad urinary bladder results in impairment of the water permeability response to vasopressin. The magnitude of the hydrosmotic response to a maximal concentration of either vasopressin or the cyclic nucleotide analogue 8-(p-chlorophenylthio)-cyclic 3',5'-adenosine monophosphate (C1PhS-cAMP) was progressively reduced when serosal bath pH was decreased from 8.5 to 6.5. The disulfonic stilbenes SITS and DIDS and the diuretic furosemide, agents known to interfere with anion transport and with the regulation of intracellular pH in other tissues, inhibited the water flow response to vasopressin and C1PhS-cAMP in a pH-dependent manner when added to the serosal bathing medium. Inhibition of the hydrosmotic response to 10(-5) M C1PhS-cAMP was estimated to be half-maximal at 1.5 X 10(-4) M SITS, 2 X 10(-5) M DIDS, and 1 X 10(-5) M furosemide. The degree of inhibition induced by the anion transport inhibitors varied inversely with the concentration of exogenous cyclic nucleotide. SITS, DIDS, and furosemide had no effect on either basal or vasopressin-stimulated short-circuit current at serosal pH 8.5; all three agents inhibited basal short-circuit current at pH 7.1 but had no effect on the natriferic response to vasopressin. These results are consistent with the view that changes in intracellular hydrogen ion and/or anion concentration can selectively inhibit the increase in water permeability elicited by vasopressin at a step(s) distal to the generation of cAMP.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1985

Determination of aluminium in serum: findings of an external quality assessment scheme.

The analytical performance of laboratories participating in the serum aluminium programme of the Guildford Trace Element Quality Assessment Scheme has been evaluated. The considerable disparity between reported results was not attributable to the nature of the samples distributed, nor to the standard aluminium solutions used in different laboratories. All laboratories used electrothermal atomic absorption spectrometry but sample preparation procedures and temperature programmes varied enormously. While some laboratories performed better than others in the scheme, and the standard of analysis appears to be improving with time, no laboratory showed consistent acceptable performance.

Aluminum↗
PubMed1985

Detection of acute synthetic vascular graft infection with 111In-labeled leukocyte scanning: an animal study.

Synthetic vascular graft infection is characterized by late diagnosis due to indolent and nonspecific symptoms. Indium-111-labeled leukocyte imaging holds promise as a diagnostic tool to identify vascular graft infection, but reported data on its accuracy are somewhat sparse and conflicting. In this study, 13 mongrel dogs received Dacron aortic interposition grafts. Seven grafts were contaminated at the time of surgery by topical ATCC Staphylococcus aureus concentrated at 10(8) organisms/ml. Six control animals received no graft contamination. All infected animals were sacrificed on the second postoperative day after 111In leukocyte scanning. The results showed a sensitivity of 71%, specificity of 100%, and accuracy of 85% for the 111In leukocyte study in detecting early graft infections; false-positive leukocyte scans in the early postoperative period were not a problem as has been reported by others. These data indicate that leukocyte scanning for graft infection detection is likely to be clinically valuable.

Animals↗
PubMed1985

Tissue disposition and excretion of gold and 14C in rats treated with sodium aurothio[1,4-14C]malate or thio [1,4-14C] malic acid.

In rats injected intramuscularly with sodium aurothio[1,4-14C]malate, 80% of the 14C was excreted in the urine, mostly in 24 h, 2% in the faeces and 10% as 14CO2 in the expired air during the first six hours with none thereafter. Urinary and faecal gold represented 5% and 2.5% of the dose, respectively. In rats given thio[1,4-14C]malic acid, 50% of the 14C was excreted in the urine, 10% in the expired air as 14CO2 and 2% in the faeces. Radioactivity was found in all tissues with distribution similar for the two compounds, the major sites of accumulation being bone, kidney and liver. Significantly higher amounts of 14C were found in the 14C-aurothiomalate-dosed animals, notably in bone and kidney. Gold was located principally in kidney, liver, lung and spleen with smaller amounts elsewhere. At least seven radioactive metabolites (including sodium aurothiomalate and thiomalic acid) were present in the urine of rats given 14C-aurothiomalate. Urine from 14C-thiomalic acid-treated rats contained at least five radiolabelled compounds, one of which was thiomalic acid. Results show that most of the gold was removed from the thiomalate moiety, however, the 14C distribution and the radioactive metabolites in urine demonstrated that some intact aurothiomalate remains.

Animals↗
PubMed1985

Macromolecule transport across the pulmonary microvessel walls.

In summary, it has been difficult to assess the permeability properties of the pulmonary capillary membrane. However, new mathematical and experimental techniques have recently been developed which are of sufficient sensitivity and specificity to begin to evaluate the complex mechanisms responsible for many forms of lung pathology. While future work will undoubtedly need to address problems associated with heterogeneity of pulmonary blood flow, and with an equally heterogeneous population of vascular permeability and fluid formation sites, we currently need to focus on using the correct experimental approaches for assessing vascular permeability. The appropriate techniques are described in the text and indicate that the measurements of reflection coefficients using lymph obtained at high vascular pressures, filtration coefficients obtained from both isolated and intact lungs, and two-pore models are useful in assessing vascular permeability.

Animals↗
PubMed1985

Longitudinal analysis of three intrathecally produced immunoglobulin subpopulations in an MS patient.

Four murine anti-idiotypic (a-Id) hybridoma antibodies were produced against immunoglobulins (Ig) present in the cerebrospinal fluid (CSF) obtained from an MS patient 2 mo after the onset of disease. The four a-Id antibodies were shown to delineate idiotopes present on three distinct Ig subpopulations designated ID-19, ID-40, and ID-97. All three Ig subpopulations were produced in part by intrathecally localized B cells, together making up approximately 5% of the total CSF-Ig 2 mo after the onset of disease. Longitudinal analysis of the concentration of these Ig subpopulations in CSF showed that two subpopulations, ID-40 and ID-97, exhibited a regular relation to the clinical course of the disease, i.e., were decreased (ID-40) or increased (ID-97) in the first CSF sample obtained after two consecutive exacerbations. Screening of sera from 52 optic neuritis patients and 51 heterologous MS patients revealed that one MS patient's serum contained an Ig subpopulation that was idiotypically cross-reactive with ID-97. So far, screening of these Ig subpopulations for reaction with several viruses (measles, parainfluenza type 1, influenza type A, cytomegalovirus, herpes simplex virus, rubella virus, poliovirus, murine encephalomyelitis viruses, and reovirus) and myelin basic protein has failed to reveal their antigen specificities.

Adult↗
PubMed1985

Differential renal function in unilateral renal injury: possible effects of radiopharmaceutical choice.

An abnormal filtration fraction or a significant divergence between a kidney's ability to extract Tc-99m dimercaptosuccinic acid (DMSA) and other function parameters, such as the glomerular filtration rate (GFR) or the effective renal plasma flow (ERPF), could lead to different estimates of relative or absolute renal function, depending on the radiopharmaceutical administered. To evaluate this possible divergence, we measured the relative GFR (I-125 iothalamate), ERPF (I-131 hippurate), and Tc-99m DMSA accumulation in adult male Sprague-Dawley rats with unilateral ureteral obstruction or unilateral ischemia at various times after renal injury. The relative ERPF of the obstructed kidney was significantly greater than the relative GFR at all time periods studied; significant but less dramatic differences were noted comparing DMSA with GFR in obstruction and DMSA and ERPF with GFR in ischemia. In evaluating renal disease, it is important to consider the functional parameter reflected by the administered radiopharmaceutical as well as the underlying disease state.

Animals↗
PubMed1985

Assessment of skin ulcer healing capability by technetium-99m phosphate angiogram and blood-pool images.

The accuracy of radionuclide angiography and blood-pool imaging using [99mTc]-phosphate to assess skin ulcer perfusion as an indicator of healing capacity was determined in 50 studies performed on 45 patients with nonhealing ulcers of the lower extremities. Two nuclear medicine physicians without clinical bias, graded the perfusion of the ulcer on the images as normal, increased or reduced with respect to the opposite limb. Patients were followed closely with aggressive local wound care for at least 14 days. Of the 31 ulcers which healed, the radionuclide study correctly predicted 30; of the 19 ulcers which did not heal, 14 were correctly predicted. Eight patients had osteomyelitis; four of those healed and four did not. The radionuclide study predicted healing in seven. Excluding those patients with osteomyelitis, the sensitivity for the radionuclide angiogram and blood-pool image in predicting healing was 96%, specificity was 87%, and accuracy was 93%. This technique is a simple, reliable way to predict the microcirculatory adequacy for ulcer healing. Specificity is diminished in the presence of osteomyelitis.

Aged↗
PubMed1985

Comparison of fully automated and manual ejection fraction calculations: validation and pitfalls.

Resting multigated blood-pool studies were performed on 61 patients without arrhythmias and data were simultaneously acquired to two computer systems. Using one computer, manual ejection fraction (EF) was calculated by two trained observers. EF was also calculated from the other computer using a commercially available fully automated program; quality control (QC) images were routinely obtained to evaluate correct left-ventricular center location, background region assignment, or gross edge mispositioning. When errors were noted, the automated analysis was reprocessed with operator intervention. Forty-eight of the 61 studies (78%) produced adequate QC images. Operator redefinition of the left ventricular center and background of the 13 QC failures raised the automated success level to 92%. Correlation of the manual EF by two observers was excellent (r = 0.969). The automated EF measurements correlated well with the average observer's (r = 0.898). An improved version of software reduced the QC failures from 13 to 10. Operator assisted automated processing gave the success rate of 94%. The remaining 6% of patients required manual processing to obtain a correct ejection fraction. Our normal range for manual EF is greater than or equal to 0.50 and our corresponding normal range for this group of patients using the automated program was greater than or equal to 0.44. Based on greater than or equal to 0.44, four patients with a low manual EF had a normal automated EF. All four patients had cardiac disease but there was no evidence of abnormal cardiac function. The fully automated program provided good correlation with manual EF and can remove some of the subjectivity in manual edge determination. However, QC images must be carefully examined and the normal EF range for the automated program must be determined.

Adult↗
PubMed1985

Value of a 24-hour image (four-phase bone scan) in assessing osteomyelitis in patients with peripheral vascular disease.

The delayed images of the four-phase 99mTc phosphonate bone scan are compared with the delayed images of the three-phase study in patients with diabetes mellitus and/or peripheral vascular disease and suspected osteomyelitis. Three-phase bone imaging includes an immediate postinjection radionuclide angiogram, a blood-pool image, and delayed static images to 7 hr. The four-phase study adds a 24-hr static image. The scan is positive for osteomyelitis if images show progressively increasing lesion to background activity ratios over time. The results of analyzing 21 three- and four-phase bone scans in 17 patients were correlated with clinical course, cultures, and/or x-rays, gallium scans, and CT scans. The accuracy of four-phase bone imaging for diagnosing osteomyelitis was 85%; for three phase, 80%. Sensitivity for four phase was 80%; specificity was 87%. Sensitivity for three phase was 100%; specificity was 73%. Since overall accuracy of the four-phase study is slightly better than three phase, in these patients with diabetes mellitus and/or peripheral vascular disease, the addition of a 24-hr image, creating a four-phase bone scan, is recommended.

Diabetic Angiopathies↗
PubMed1985

No difference in sensitivity for occult infection between tropolone- and oxine-labeled indium-111 leukocytes.

There is considerable disagreement as to whether oxine or tropolone is the best labeling agent for indium leukocytes. We have previously looked at the sensitivity of oxine-labeled 111In leukocyte scans for occult infections and now present a similar group of patients imaged with tropolone-labeled 111In leukocytes. Thirty-four patients (38 studies) with possible occult infection were prospectively studied. Patients were imaged 1-4 hr after injection and again at 24 hr postinjection. The early tropolone images had a sensitivity of 53% while the delayed images at 24 hr had a sensitivity of 93%. Based on a previous study, oxine-labeled leukocyte scans have an early sensitivity of 33% and a delayed sensitivity (at 24 hr) of 95%. The differences in sensitivity between oxine and tropolone when imaged early and at 24 hr were not statistically significant. We conclude that there is no significant difference in the ability to detect infection between oxine- and tropolone-labeled leukocytes, both early at 1-4 hr, and on delayed imaging 24 hr after injection.

Abscess↗