2-¹8fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) for postchemotherapy seminoma residual lesions: a retrospective validation of the SEMPET trial.

BACKGROUND: 2-¹8fluoro-deoxy-D-glucose positron emission tomography (FDG-PET) has been recommended in international guidelines in the evaluation of postchemotherapy seminoma residuals. Our trial was designed to validate these recommendations in a larger group of patients. PATIENTS AND METHODS: FDG-PET studies in patients with metastatic seminoma and residual masses after platinum-containing chemotherapy were correlated with either the histology of the resected lesion(s) or the clinical outcome. RESULTS: One hundred and seventy seven FDG-PET results were contributed. Of 127 eligible PET studies, 69% were true negative, 11% true positive, 6% false negative, and 15% false positive. We compared PET scans carried out before and after a cut-off level of 6 weeks after the end of the last chemotherapy cycle. PET sensitivity, specificity, negative predictive value (NPV), and positive predictive value were 50%, 77%, 91%, and 25%, respectively, before the cut-off and 82%, 90%, 95%, and 69% after the cut-off. PET accuracy significantly improved from 73% before to 88% after the cut-off (P=0.032). CONCLUSION: Our study confirms the high specificity, sensitivity, and NPV of FDG-PET for evaluating postchemotherapy seminoma residuals. When carried out at an adequate time point, FDG-PET remains a valuable tool for clinical decision-making in this clinical setting and spares patients unnecessary therapy.

Long-term follow-up of patients with GIST undergoing metastasectomy in the era of imatinib -- analysis of prognostic factors (EORTC-STBSG collaborative study).

BACKGROUND: Long-term complete remissions remain a rare exception in patients with metastatic gastrointestinal stromal tumors (GIST) treated with IM (imatinib). To date the therapeutic relevance of surgical resection of metastatic disease remains unknown except for the use in palliative intent. PATIENTS AND METHODS: We analyzed overall survival (OS) and progression-free survival (PFS) in consecutive patients with metastatic GIST who underwent metastasectomy and received IM therapy (n = 239). RESULTS: Complete resection (R0+R1) was achieved in 177 patients. Median OS was 8.7 y for R0/R1 and 5.3 y in pts with R2 resection (p = 0.0001). In the group who were in remission at time of resection median OS was not reached in the R0/R1 surgery and 5.1 y in the R2-surgery (p = 0.0001). Median time to relapse/progression after resection of residual disease was not reached in the R0/R1 and 1.9 years in the R2 group of patients, who were resected in response. No difference in mPFS was seen in patients progressing at time of surgery. CONCLUSIONS: Our analysis implicates possible long-term survival in patients in whom surgical complete remission can be achieved. Incomplete resection, including debulking surgery does not seem to prolong survival. Despite the retrospective character and likely selection bias, this analysis may help in decision making for surgical approaches in metastatic GIST.

Microwave-assisted extraction of polycyclic aromatic compounds from coal.

Microwave-assisted extraction (MAE) of polycyclic aromatic compounds (PACs) from coal is shown to give the same pattern of compounds as Soxhlet extraction. MAE requires only 10 mL solvent and 10 min extraction time whereas Soxhlet uses 200 mL and takes 24 h. Although the yields were lower, dichloromethane (DCM) was preferred to pyridine, N-methyl-2-pyrrolidone (NMP), and NMP with CS2 because the pattern of the PACs is shown to be independent of solvent and DCM is a much more convenient solvent to work with.

Binding characteristics of dimeric IgG subclass complexes to human neutrophils.

Immune complexes were prepared by incubation of human IgG paraproteins with F(ab')2 fragments of the mAb K35 against the kappa-L chain of human IgG. The composition of these complexes was analyzed by centrifugation over sucrose gradients, by gel filtration, by RIA with either IgG Sepharose or K35 Sepharose and by double-labeling studies. The results indicated that the complexes consist of saturated tetramers composed of two IgG molecules cross-linked by two F(ab')2 fragments of the mAb. These complexes were used to study the binding of the different IgG subclasses to human neutrophils at 4 degrees C. Human neutrophils bound IgG3 complexes approximately three times faster than IgG1 complexes. Binding of IgG2 or IgG4 dimers to the neutrophils was undetectable. The same number of IgG1 complexes and IgG3 complexes bound to the neutrophils, but considerable inter-donor variation was found (mean number of Fc gamma R per neutrophil: 190,000, range 120,000 to 400,000). The Ka for the binding of IgG1 complexes to neutrophils (median 11 x 10(7) M-1) was lower than the Ka for the binding of IgG3 complexes (median 47 x 10(7) M-1). Competition studies between labeled IgG1 complexes or IgG3 complexes and unlabeled complexes showed that the Fc gamma R of human neutrophils do not display an IgG subclass specificity. Incubation of neutrophils with a mAb against the FcRIII completely blocked the binding of IgG1 complexes and IgG3 complexes. Incubation with a mAb against the FcRII reduced the affinity of the complexes for the neutrophils but had no effect on the maximum number of complexes bound. This indicates that one complex may bind simultaneously to one FcRIII and to one FcRII.