We used PET with the tracers [18F]fluorodeoxyglucose (FDG), [18F]fluorodopa (FDOPA) and [11C]raclopride (RACLO) to study striatal glucose and dopa metabolism, and dopamine D2 receptor binding, respectively, in nine patients with multiple system atrophy. Ten patients with classical Parkinson's disease were investigated with the same three PET tracers' and three separate groups, each of 10 healthy subjects, served as control populations. We found that striatal FDOPA values separated all healthy subjects from patients with parkinsonism but they were not useful in distinguishing multiple system atrophy from Parkinson's disease. Conversely, striatal RACLO as well as FDG values discriminated all multiple system atrophy from Parkinson's disease patients as well as from healthy control subjects. Metabolic and receptor binding decrements in the putamen of multiple system atrophy patients were significantly correlated. Stepwise regression analysis revealed that a linear combination of putamen RACLO and FDOPA values accurately predicted clinical measures of disease severity in the multiple system atrophy group. Our findings suggest that striatal FDG and particularly RACLO are sensitive and effective measures of striatal function and may help characterizing patients with multiple system atrophy. In contrast, FDOPA measurements are accurate in detecting abnormalities of the nigrostriatal dopaminergic system but may not distinguish among different forms of parkinsonism.

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Background: Ether lipids could provide new prospects in cancer therapy after successful preclinical investigations. Edelfosine has been the most thoroughly investigated substance in the ether lipid group. So far, no standard therapy has been set up for advanced non-small-cell bronchogenic carcinoma. Therefore, in a phase II study 116 patients with advanced inoperable non-small-cell bronchogenic carcinoma were treated with the alkyl-lysophospholipid edelfosine (EF). Material and Methods: The phenotype modifier EF was initially applied in a daily oral dosage of 300 mg (dissolved in milk) over a period of 4 weeks, then increased to a daily dosage of 900 mg if tolerated well, and continued with the highest tolerable dosage. Therapy was continued until either tumor progression or negative side effects were documented. 35 patients could not be treated for the intended therapy period of at least 8 weeks due to early tumor progression (18 patients), unacceptable gastrointestinal side effects (14 patients), lack of compliance (1 patient), refusal of therapy (1 patient) and change of therapy (1 patient). Results: 81 patients could be evaluated for remission status; of these, 2 showed partial remission, 68 showed ‘no change’, and 11 had unaltered progression of the tumor. Median survival time for these 81 patients was 244 days, for all 116 patients it was 199 days. Retrospectively, in these 81 patients the spontaneous tumor development during the 2 months before EF therapy could be analyzed. Tumor progression during this period could be documented in 1 patient with partial remission, in 46 patients with diagnosis ‘no change’, and in 11 patients with unaltered tumor progression. The survival times of these three groups of patients did not differ significantly. All 116 patients were evaluable for toxicity. Manifestations of gastrointestinal problems were anorexia, nausea, vomiting, diarrhea, obstipation (mostly WHO grades I+Π), but treatment was not required. Toxic effects on organs or late toxicity could not be documented.Conclusions: The high proportion of patients with stationary tumor status was remarkable. Objective tumor remission was extremely rare. On the other hand, the rate of progression was low. This might be explained by the fact that EF is rather a phenotype modifier than a typical cytostatic drug.

Iron and transferrin are required for DNA synthesis and cell division. Cellular iron uptake is mediated by transferrin receptors. In order to investigate whether iron uptake in brain tumors is associated with their histological grade, we studied 24 patients (5 astrocytoma, 11 glioblastoma, 8 meningioma) using positron emission tomography and 52Fe-citrate. Tracer uptake from blood into brain and tumor tissue was assessed 1. using multiple time graphical analysis yielding a measure for unidirectional net tracer uptake (Ki) and 2.) testing a one- and two-tissue kinetic compartment model, where K1 denotes tracer uptake from blood into tissue, k2 efflux from tissue into plasma, and k3 specific tracer binding. In the plasma, 52Fe was bound to a 80 kD protein (transferrin). Ki (in units of 10(-5)/min) was higher in glioblastomas (Ki mean +/- SD 13.6 +/- 6.1) compared with astrocytomas (4.8 +/- 3.5, Mann Whitney p = 0.015) and contralateral brain (2.2 +/- 0.9, Mann Whitney p = 0.009). Highest values were found in meningiomas (no blood-brain barrier (BBB); Ki 33.4 +/- 16.5, Mann Whitney p = 0.008 compared with glioblastomas). Among the compartment models, fitting with K1 and regional plasma volume explained the data best (one-tissue model), data fits were not significantly improved by addition of a k2 or k3 parameter. K1 and Ki values were significantly correlated (Spearman Rank, p = 0.0006). We conclude that 52Fe accumulation in tumors is governed by tracer uptake at the BBB, and does not reflect number of transferrin receptors at the level of tumor cells.

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