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Biomedical subjects

E Wolfe

Publications and source records attributed to E Wolfe.

8 recordsLinked to original sources
PubMed1990

Noninvasive evaluation of sympathetic nervous system in human heart by positron emission tomography.

The noninvasive functional characterization of the cardiac sympathetic nervous system by imaging techniques may provide important pathophysiological information in various cardiac disease states. Hydroxyephedrine labeled with carbon 11 has been developed as a new catecholamine analogue to be used in the in vivo evaluation of presynaptic adrenergic nerve terminals by positron emission tomography (PET). To determine the feasibility of this imaging approach in the human heart, six normal volunteers and five patients with recent cardiac transplants underwent dynamic PET imaging after intravenous injection of 20 mCi [11C]hydroxyephedrine. Blood and myocardial tracer kinetics were assessed using a regions-of-interest approach. In normal volunteers, blood 11C activity cleared rapidly, whereas myocardium retained 11C activity with a long tissue half-life. Relative tracer retention in the myocardium averaged 79 +/- 31% of peak activity at 60 minutes after tracer injection. The heart-to-blood 11C activity ratio exceeded 6:1 as soon as 30 minutes after tracer injection, yielding excellent image quality. Little regional variation of tracer retention was observed, indicating homogeneous sympathetic innervation throughout the left ventricle. In the transplant recipients, myocardial [11C]hydroxyephedrine retention at 60 minutes was significantly less (-82%) than that of normal volunteers, indicating only little non-neuronal binding of the tracer in the denervated human heart. Thus, [11C]hydroxyephedrine, in combination with dynamic PET imaging, allows the noninvasive delineation of myocardial adrenergic nerve terminals. Tracer kinetic modeling may permit quantitative assessment of myocardial catecholamine uptake, which will in turn provide insights into the effects of various disease processes on the neuronal integrity of the heart.

Adult↗
PubMed1990

Three-dimensional assessment of myocardial oxidative metabolism: a new approach for regional determination of PET-derived carbon-11-acetate kinetics.

We have developed a new analysis algorithm which generates polar coordinate maps of myocardial carbon-11-(11C) acetate kinetics. In 10 normal subjects (n = 20 studies), myocardial 11C clearance rate constants (k) averaged 0.057 +/- 0.009 (per minute). Regional k-values varied only 10.6 +/- 2.4% in the normal left ventricle. However, there was a small but significant segmental variation with increased 11C clearance in the septal, anterior, and basal regions (p less than 0.05). Since 11C clearance rates reflect tri-carboxylic acid cycle flux, these results suggest that myocardial oxidative metabolism is relatively homogeneous in the normal human heart at rest with minor regional variations, which possibly reflect varying regional wall stresses or substrate utilization. The proposed approach provides three-dimensional evaluation of regional oxidative metabolism which will permit characterization of the location, extent, and severity of myocardial disease.

Acetates↗
PubMed1988

Carotenodermia in men with elevated carotenoid intake from foods and beta-carotene supplements.

We evaluated the relation between plasma levels of carotenoids and carotenodermia in 30 men receiving carotenoid supplementation for 42 d. Five subjects each were randomly assigned to one of six treatment groups: 30 mg purified beta-carotene supplement, 12 mg beta-carotene supplement, 272 g cooked carrots, 300 g cooked broccoli, 180 g tomato juice, and placebo. Definite carotenodermia was observed only in the five subjects who took 30 mg of purified beta-carotene daily. Carotenodermia was first noted between 25 and 42 d after supplementation and persisted from 14 to greater than 42 d posttreatment and was observed only after plasma total carotenoid levels exceeded 4.0 mg/L. These observations may be useful to investigators planning clinical trials with beta-carotene and to clinicians assessing the significance of carotenodermia in men taking beta-carotene supplements or following diets high in carotenoid-containing foods.

Adult↗
PubMed1988

Strike!

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Humans↗
PubMed1987

A randomized study of oral nutritional support versus ad lib nutritional intake during chemotherapy for advanced colorectal and non-small-cell lung cancer.

One hundred ninety-two patients with previously untreated metastatic cancer (102 non-small-cell lung cancer [NSCLC]; 90 colorectal cancer) were randomized to receive either ad lib nutritional intake (control group) or specific nutritional intervention during a 12-week study period when chemotherapy was administered. Those patients randomized to nutritional interventions were counselled to take oral nutrients with caloric intake equal to 1.7 to 1.95 times their basal energy expenditure, depending on their pretreatment nutritional status ("standard" group). An augmented group was counselled to have a caloric intake equivalent to that of the standard group but with 25% of calories provided as protein and additional supplements of zinc and magnesium. Counselling increased caloric intake in both tumor types but reduced weight loss in the short term only for lung cancer patients. Ninety-three NSCLC patients were evaluable for tumor response to vindesine and cisplatin. Overall, only 20.4% of the patients responded, and there were no significant differences in response rates, median time to progression, or overall duration of survival between the nutrition intervention groups and the control group. The tumor response rate to time-sequenced 5-fluorouracil (5-FU) and methotrexate in the 81 evaluable patients with colorectal cancer was only 14.8%, and no significant differences in tumor response rates were noted between the three groups. Furthermore, the median time to progression and overall duration of survival were not different for the control, standard, and augmented groups. Nutritional interventions using dietary counselling had no impact on the percent of planned chemotherapy dose administered, the degree of toxicity experienced by patients, or the frequency of treatment delays. A multivariate prognostic factor analysis demonstrated that for lung cancer, the percent of weight loss, serum albumin concentration, and presence of liver metastases were significant (P less than .05) and independent prognostic variables for survival duration. For colorectal cancer, serum albumin, alkaline phosphatase, lactic dehydrogenase (LDH) levels, and percent targeted caloric intake (TCI) were significant independent predictors of survival duration.

Adult↗
PubMed1985

Informed consent.

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Dental Care↗