Prognostic role of pretreatment 18F-FDG PET/CT in primary brain lymphoma.

Objective: Primary brain lymphoma is an aggressive extranodal non-Hodgkin lymphoma with poor prognosis. Many possible prognostic factors are investigated with controversial results, but possible prognostic role of 18fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) features remains unclear. Our aim was to study the metabolic behavior of brain lymphoma at 18F-FDG PET/CT and the prognostic impact of qualitative and semiquantitative PET/CT parameters.

Comparison between the summed difference score and myocardial blood flow measured by N-ammonia.

Background: Both the myocardial perfusion pattern and myocardial blood flow (MBF) are used to assess patients with suspected coronary artery disease (CAD). The aim of this study was to compare the perfusion pattern (using the summed difference score [SDS]) to MBF in a consecutive group of patients undergoing PET/CT with 13 N-ammonia (NH).

Methods: 47 consecutive patients, aged 65 ± 12 years (42 men) with known or suspected CAD, underwent vasodilator stress/rest PET/CT with NH for clinical indications.

The strange case of the [13N]NH3: validation of the production process for human use.

Objective: PET radiopharmaceuticals are often injected in patients before all quality controls are performed and before sterility results are available. We propose a process validation to produce very safe and pure [N]NH3 for human use.

Methods: [N]NH3 was produced in the cyclotron target.

Drop of connexins: a possible link between aging and cancer?

The incidence of cancer increases with age but we do not know why. As a working hypothesis we propose here that cells somehow initiated in vivo in the course of life and finally engaged in the aging program, which involves a drop of connexins with loss of cell-to-cell communication (equivalent to the promotion phase in the multistep process of carcinogenesis), may recover their growth potential, thus allowing cancer to progress. This is supported by evidence that: (i) connexin 43 (Cx43) acts as a tumor suppressor; (ii) cx43 and gap junction intercellular communication drop in precancerous lesions and in tumors of various origins, as well as in aging cells; (iii) telomerase is activated in cancerous somatic cells.

Drop of connexin 43 in replicative senescence of human fibroblasts HEL-299 as a possible biomarker of senescence.

The expression of connexin 43 (cx43) and cell-cell communication were studied in replicative senescence of cultured HEL-299 fibroblasts. A progressive decrease in fluorescent dye transfer was detected by a scrape-loading technique in aging fibroblasts. This change was accounted for by a marked decrease in the amount of cx43 in aging cells, as detected by western blot analysis (cell extracts) and indirect fluorescence (cells in culture).