The DNA binding activity of the c-jun proto-oncogene product is inhibited by oxidation of a specific cysteine residue Modulating the level of expression of specific genes is a prerequisite for the control of cellular growth and differentiation. Gene expression is controlled by sequence-specific DNA binding proteins (transcription factors) which in certain cases are targets for signals transduced from cell surface receptors. The importance of this process for growth control is emphasized by the finding that several proto-oncogenes, including c-myc, c-myb, c-fos, and c-jun, encode sequencespecific transcription factors (reviewed in reference 20). Although the activity of these factors can be modulated by phosphorylation (4, 11), recent evidence has emerged for an additional and unusual form of regulation of DNA binding activity mediated by changes in reduction-oxidation (redox) status.

Association of the CYBA 242T allele with reduced NAD(P)H oxidase activity in human blood vessels suggests that genetic variation in NAD(P)H oxidase components may play a significant role in modulating superoxide production in human atherosclerosis.

ObjectivesInvestigate the effect of a novel Bayesian penalised likelihood (BPL) reconstruction algorithm on analysis of pulmonary nodules examined with 18F-FDG PET/CT, and to determine its effect on small, sub-10-mm nodules.Methods18F-FDG PET/CTs performed for nodule evaluation in 104 patients (121 nodules) were retrospectively reconstructed using the new algorithm, and compared to time-of-flight ordered subset expectation maximisation (OSEM) reconstruction. Nodule and background parameters were analysed semi-quantitatively and visually.ResultsBPL compared to OSEM resulted in statistically significant increases in nodule SUVmax (mean 5.3 to 8.1, p < 0.00001), signal-to-background (mean 3.6 to 5.3, p < 0.00001) and signal-to-noise (mean 24 to 41, p < 0.00001). Mean percentage increase in SUVmax (%ΔSUVmax) was significantly higher in nodules ≤10 mm (n = 31, mean 73 %) compared to >10 mm (n = 90, mean 42 %) (p = 0.025). Increase in signal-to-noise was higher in nodules ≤10 mm (224 %, mean 12 to 27) compared to >10 mm (165 %, mean 28 to 46). When applying optimum SUVmax thresholds for detecting malignancy, the sensitivity and accuracy increased using BPL, with the greatest improvements in nodules ≤10 mm.ConclusionBPL results in a significant increase in signal-to-background and signal-to-noise compared to OSEM. When semi-quantitative analyses to diagnose malignancy are applied, higher SUVmax thresholds may be warranted owing to the SUVmax increase compared to OSEM.Key Points• Novel Bayesian penalised likelihood PET reconstruction was applied for lung nodule evaluation.• This was compared to current standard of care OSEM reconstruction.• The novel reconstruction generated significant increases in lung nodule signal-to-background and signal-to-noise.• These increases were highest in small, sub-10-mm pulmonary nodules.• Higher SUVmaxthresholds may be warranted when using semi-quantitative analyses to diagnose malignancy.