Uptake of positron emission tomography tracers in experimental bacterial infections: a comparative biodistribution study of radiolabeled FDG, thymidine, L-methionine, 67Ga-citrate, and 125I-HSA.

The purpose of this study was to evaluate the localization of positron emission tomography (PET) tracers [2-deoxy-2-fluoro-D-glucose (FDG), thymidine, and L-methionine] in sites of bacterial infection, and to contrast this with that of other tracers. The left calf muscles of rats were infected with a suspension of Escherichia coli and the biodistribution of 18F- or 3H-FDG, 3H-thymidine, L-11C- or 3H-methionine, gallium-67 citrate (67Ga-citrate) and iodine-125 human serum albumin (125I-HSA) was determined in these animals. 3H-FDG uptake in the infectious foci was evaluated by autoradiography of histological sections. Although 18F-FDG, 67Ga-citrate, and 125I-HSA showed comparatively high uptake in the infected muscle [the percentage activity of injected dose (ID) per gram of tissue normalized for rat weight in kilogram (%ID/g)xkg at 2 h postinjection was as follows: 18F-FDG, 0.184+/-0.026 to 0.218+/-0.046; 67Ga-citrate, 0.221+/-0.016; 125I-HSA, 0. 198+/-0.019], the infected muscle to blood ratio was much higher for 18F-FDG than for 67Ga-citrate or 125I-HSA (18F-FDG, 10.31+/-0.76 to 14.89+/-2.26; 67Ga-citrate, 1.24+/-0.67; 125I-HSA, 0.20+/-0.02). The draining reactive lymph nodes also showed higher accumulation of 18F-FDG than of 67Ga-citrate or 125I-HSA. The uptake of 3H-thymidine and L-11C- or 3H-methionine in the infected muscle was lower than that of 18F- or 3H-FDG (at 2 h postinjection, 3H-thymidine = 0. 039+/-0.005 and L-3H-methionine = 0.063+/-0.007 (%ID/g)xkg. Autoradiographs showed that the highest 3H-FDG uptake was seen in the area of inflammatory cell infiltration surrounding the necrotic region. In conclusion, 18F-FDG, which rapidly accumulates in sites of bacterial infection and in reactive lymph nodes with a high target to background ratio, appears to be a promising infection detection agent.

Abrupt vessel closure following platelet transfusion post-PTCA.

A successful PTCA was complicated by abrupt closure following a platelet transfusion which was given for control of local bleeding. Possible mechanisms of abrupt closure are discussed. Recommendation is made to avoid giving platelet transfusion following PTCA.

Low rate of treatment of hypercholesterolemia by cardiologists in patients with suspected and proven coronary artery disease.

BACKGROUND: Although specific guidelines for the treatment of hypercholesterolemia have been published, it is not known whether physicians treating patients likely to have lipid disorders have adopted the recommendations. METHODS AND RESULTS: The approach of cardiologists to the treatment of hypercholesterolemia in a metropolitan teaching hospital was assessed by interviewing patients with chest pain who were admitted for coronary angiography in 1988-1989 and by measuring fasting blood lipid profiles. At 1 month and again 12-24 months later, patients were contacted by telephone to determine if there had been any changes in treatment. Of 95 patients evaluated, 81 had coronary artery disease. Only 17% of those with high levels of total cholesterol and/or low density lipoprotein cholesterol were being actively treated with diet and/or drugs. In the remaining patients, either lipid studies had not been done or abnormal results had not been addressed. There was little change in treatment approach during the month after the diagnostic procedure. Furthermore, the experience was similar in those patients subjected to coronary revascularization. One to 2 years after the initial intervention, 69 of the original study group could be contacted again. Although active dietary or pharmacological therapy was initiated in some individuals during this interval, it was stopped in others. Thirty-five percent of hypercholesterolemic patients were receiving targeted therapy. CONCLUSIONS: Thus, only a small proportion of patients with documented coronary artery disease and hypercholesterolemia were being actively treated for their lipid disorder, suggesting that the published treatment guidelines have not yet been fully accepted. However, an encouraging improvement in frequency of treatment of hypercholesterolemia was documented during the 1-2-year observation period.

Vasospasm in a coronary artery aneurysm.

Coronary artery aneurysms are not believed to have enough intact smooth muscle to generate significant vasoconstriction. A case is presented illustrating vasospasm of a large fusiform aneurysm of a right coronary artery during angioplasty. Pathophysiology of aneurysms is discussed.