As positron emission tomography (PET) is outside of the main theme of this conference, it is necessary to outline what it offers as a method for assessing tissue function in vivo. This is followed by illustrations of how PET has and is being used to study the physiology and biochemistry of tumours and pharmacokinetics and pharmacology of anticancer agents. Strategies are offered as to how PET may be used for the development of new chemotherapeutic agents.

Fluorouracil↗

PubMedDate not supplied

Blood versus bone marrow ethanol concentrations in rabbits and humans.

Post-mortem ethanol levels in bone marrow and heart blood were determined in rabbits and humans. The average ratio of blood/femur marrow ethanol in 39 rabbits was 2.10 +/- 0.23 with a range of 1.27 - 3.50. In 18 human autopsy cases the average ratio of blood/rib marrow ethanol levels was 2.16 +/- 0.32 with a range of 1.65 - 2.94. The average blood/marrow ratios in humans and rabbits were comparable. However, a wider range of ratios was noticed in the rabbit study.

Adult↗

PubMedDate not supplied

VLSI in biomedical imaging systems.

This paper explores the nature of Very Large Scale Integration (VLSI) systems as applied to the area of medical imaging systems. A general discussion of imaging systems and the techniques employed therein will be presented. With this, the merits of VLSI solutions to the medical imaging problem are presented. Consideration is also given to programmable processors, such as off the shelf DSP processors, semi-custom, and full custom VLSI devices. Through the use of VLSI devices, many image processing algorithms can be integrated into a hardware solution. This has the advantage of increased computational capacity over solutions that would normally employ software techniques.

Algorithms↗

PubMedDate not supplied

Faculty development and support needs of nurse practitioner faculty.

Explore the source record for details and available documents.

Educational Status↗

PubMedDate not supplied

15O positron emission tomographic scanning in predominantly never-treated acute schizophrenic patients.

Positron emission tomography with oxygen-15 was used to compare regional cerebral blood flow and the regional cerebral metabolic rate of oxygen in a group of predominantly never-treated, acute schizophrenic patients and in matched controls. The results of this study did not support the hypothesis that schizophrenics have reduced frontal blood flow and/or metabolism; and only equivocal support was obtained for the hypothesis that metabolism within the basal ganglia is reduced in schizophrenics. However, support was obtained for the hypothesis that an abnormality in hemisphere laterality may underlie schizophrenic illness.

Acute Disease↗

PubMedDate not supplied

Effect of long-term beta2-agonist dosing on human cardiac beta-adrenoceptor expression in vivo: comparison with changes in lung and mononuclear leukocyte beta-receptors.

BACKGROUND: Tachyphylaxis to the cardiac effects of beta-adrenoceptor stimulation after long-term beta2-agonist administration is well recognized, but the influence on global cardiac beta-adrenoceptor density has not been previously investigated in vivo. Positron emission tomography (PET) has made possible the noninvasive quantification of regional receptor density. This study assesses the effect of long-term beta2-agonist dosing on cardiac beta-adrenoceptors. METHODS AND RESULTS: Beta-adrenoceptors in the hearts of 29 healthy male subjects aged 35 +/- 8 years were imaged and quantified in vivo by means of PET and compared with the receptor density in the same subjects' lung tissue. Mononuclear leukocyte (MNL) beta-receptor density was determined in vitro by means of a radioligand binding assay. Beta-receptor density was 8.41 +/- 2.03 pmol/gm tissue in heart, 10.81 +/- 1.91 pmol/gm tissue in lung, and 38.0 +/- 17.5 fmol/mg protein on MNLs. There was a weak relationship between cardiac and pulmonary beta-receptor densities (r = 0.45, p < 0.02) but not between cardiac and MNL receptor density. In seven subjects, the measurements were repeated after 2 weeks of albuterol treatment (4 mg orally twice daily and 200 microg inhaled four times daily in the first week, with doubling of the dose during the second week). After the albuterol treatment, beta-receptor density fell on average by 19% (p < 0.05) in the heart compared with 22% (p < 0.05) in the lung and 42% (p < 0.05) in MNLs. Correlations were found between the percentage changes in receptor density in heart and lung (r = 0.98, p < 0.001) and in heart and MNLs (r = 0.99, p < 0.002). CONCLUSIONS: Two weeks of high-dose albuterol results in equivalent downregulation of beta-receptors in vivo, both in the lung and in the heart.

Adrenergic beta-2 Receptor Agonists↗

PubMedDate not supplied

Dipyridamole-induced increased glucose uptake in patients with single-vessel coronary artery disease assessed with PET.

BACKGROUND: The aim of this study was to determine the relationship between vasodilatation-induced ischemia and poststress glucose uptake. Coronary vasodilators may induce myocardial ischemia due to coronary steal through collateral circulation or transmural blood flow redistribution with diminished subendocardial perfusion. Myocardial ischemia can be demonstrated by increased glucose uptake as previously shown in patients with exercise-induced ischemia. METHODS AND RESULTS: We studied 11 patients with single-vessel disease and no history of myocardial infarction. Five patients had no collateral circulation, and 6 had angiographic evidence of collateral vessels. We measured myocardial blood flow (MBF) and glucose uptake at baseline and after the administration of dipyridamole (0.56 mg/kg) with positron emission tomography, using O-15 water and fluorine 18 deoxyglucose (FDG) as perfusion and glucose tracers. MBF at baseline was 0.82 +/- 0.13 mL/g/min in normal areas and 0.80 +/- 0.15 mL/g/min in areas supplied by stenotic arteries. MBF during dipyridamole was 2.05 +/- 0.66 and 1.19 +/- 0.66 mL/g/min in normal areas and areas with stenotic arteries, respectively (P < or = .001). FDG uptake at baseline was 1.36 +/- 0.55 in normal areas and 1.57 +/- 0.62 in areas supplied by stenotic arteries. FDG uptake after dipyridamole infusion was 1.79 +/- 1.1 and 4.04 +/- 0.84 in normal areas and areas with stenotic arteries, respectively (P < or =.001). MBF and FDG uptake were not different between patients with collateral circulation and those without collateral circulation. CONCLUSIONS: Increased myocardial glucose uptake was consistently observed after dipyridamole administration in those areas with diminished coronary vasodilatory capacity. The similar MBF and FDG findings in patients with and without collateral circulation may indicate that transmural blood flow redistribution appears to be a possible mechanism of dipyridamole-induced myocardial ischemia.

Blood Glucose↗

PubMedDate not supplied

Functional capacity evaluation of manual materials handlers: a review.

PURPOSE: To summarize currently existing research regarding the assessment of functional capacity in low back injured workers. METHOD: Literature review. RESULTS: Methods of functional capacity evaluation are described and critical components of an examination of functional capacity identified in relationship to federal occupational categorization and guidelines. CONCLUSIONS: Evaluation of the predictive validity of existing functional capacity evaluation templates is not possible given the absence of thorough descriptions in the published literature. While substantial research exists enabling comparison of the injured workers' manual materials handling ability to normative psychophysical data the validity of this approach remains uncertain.

Humans↗

PubMedDate not supplied

Effect of graft bed on long-term functional results of extremity skin grafts.

The purpose of the current study was to determine whether the long-term functional results of extremity burns grafted on fat were different from those grafted on fascia. Twelve patients (mean burn size, 38% TBSA) who had fascial excision of the majority of one or more extremities were examined a minimum of one year postinjury. Range of motion, motor strength, and sensation of the fascially excised extremities were measured. Twelve comparable patients with extremity burns (mean burn size, 35% TBSA) who had grafts placed on fat were used as positive controls. Patients whose burns were excised to fat had better joint mobility (P = 0.001) and sensory function (P = 0.001) than did patients whose burns were excised to fascia. Both groups had comparable muscle strength. These results indicate that patients with full-thickness burns of the extremities who have grafts placed on fat have significantly better long-term extremity function than do patients who have their skin grafts placed on fascia.

Adipose Tissue↗

PubMedDate not supplied

Morphine-Infused silver sulfadiazine (MISS) cream for burn analgesia: a pilot study.

Pain is considered the most distressing symptom of a burn wound, with analgesia usually provided via oral or parenteral medications. Use of systemic opioids can be complicated by fluctuations in bioavailability, absorption, and clearance of drugs caused by the burn. There has been little research done in the area of topical medications for burn analgesia. The following is a double-blind, placebo-controlled pilot study assessing the safety (side effects) and efficacy (pain ratings and medications administered) of morphine-infused silver sulfadiazine cream for burn pain. Four patients are reported on (2 in each group). Only participants taking placebo reported side effects related to morphine and necessitated anxiolytic medications. Pain ratings in the treatment group ranged from 0 to 7 with a mean of 2.1, whereas the placebo group's ratings ranged from 2 to 8 with a mean of 5.6. The placebo group averaged 55.3 mg oral morphine per half day, whereas the treatment group averaged 42.9 mg.

Administration, Topical↗

PubMedDate not supplied

Influence of intravascular activity on the determination of blood flow and oxygen extraction in normal and ulcerated legs using the 15O steady-state technique and positron emission tomography.

An analysis using the 15O steady-state inhalation technique has been carried out into the effects of correction for intravascular activity on the determination of blood flow and oxygen extraction ratio (OER) in the legs of patients affected by ulceration. Transaxial images of the distribution of activity in a plane passing through the ulcer were obtained during steady-state inhalation of C15O2 and 15O2, respectively, using a single slice positron emission tomographic scanner. From these, the basic tracer model equations were solved to obtain blood flow and oxygen extraction with and without additional correction for the presence of intravascular activity. The latter was obtained from a scan following the inhalation of a tracer quantity of 11CO, which labels the red blood cell pool. Mean blood flow and OER in ulcerated regions were 0.087 ml/ml/min and 0.33, respectively. With correction for blood volume, assumed to be all venous, the mean OER decreased to 0.12. In the "mirror" region of normal legs mean blood flow was 0.011 ml/ml/min with uncorrected and corrected OER values of 0.87 and 0.75, respectively. The effect of assuming a nonzero arterial volume increases as flow and OER decrease but is uncertain due to the unknown arterial fraction. Correction for intravascular 15O is essential and generally the assumption that all blood volume is venous is adequate.

Humans↗

PubMedDate not supplied

Rubidium-82 myocardial uptake and extraction after transient ischemia: PET characteristics.

The effects of transient regional ischemia on monovalent cation uptake and extraction by the myocardium were studied in seven open chest dogs. Following a 10-20% stenosis of the left anterior descending coronary artery to prevent reactive hyperemia, the regional myocardial uptake of the monovalent cation 82Rb (ml/min/g X extraction) was measured before, during, and at 10, 30, and 60-80 min after a 10 min total occlusion of the left anterior descending coronary artery using positron emission tomography. Regional myocardial blood flow was also measured at the same time interval using radiolabeled carbonized microspheres. The regional myocardial extraction of 82Rb was calculated as uptake/flow. In normally perfused myocardial regions there was an inverse relationship between 82Rb extraction and blood flow [extraction = -0.56 (In flow) + 0.46, r = 0.93] over a range of flow from 0.3 to 4 ml/min/g. During the prolonged recovery of 82Rb uptake in the transiently ischemic region, flow had returned to normal levels but 82Rb extraction at a given value of flow was significantly decreased at the 30 and 60-80 min times after release of the occlusion compared with normally perfused regions. Thus, prolonged abnormalities in the 82Rb uptake and extraction occur in myocardium recovering from transient ischemia.

Animals↗