Prognostic value of metabolic tumor volume and lesion dissemination from baseline PET/CT in patients with diffuse large B-cell lymphoma: Further risk stratification of the group with low-risk and high-risk NCCN-IPI.

PURPOSE: The purpose of this study was to determine the prognostic value of metabolic tumor volume and lesion dissemination from baseline PET/CT in patients with diffuse large B-cell lymphoma (DLBCL) and the prognostic value of them in the National Comprehensive Cancer Network International Prognostic Index (NCCN-IPI) subgroups. METHODS: A total of 113 patients who underwent 18F-FDG PET/CT examination in our institution were retrospectively collected. The MTV was measured by iterative adaptive algorithm. The location of the lesion was obtained according to its three-dimensional coordinates, and Dmax was obtained. SDmax is derived from Dmax standardized by body surface area (BSA). The X-tile method was used to determine the optimal cut-off values for MTV, Dmax and SDmax. Cox regression analysis was used to perform univariate and multivariate analyses. Patient survival rates were derived from Kaplan-Meier curves and compared using the log-rank test. RESULTS: The median follow-up time was 24 months. The median of MTV was 196.86 cm3 (range 2.54-2925.37 cm3), and the optimal cut-off value was 489 cm3. The median of SDmax was 0.25 m-1 (range 0.12-0.51 m-1), and the best cut-off value was 0.31 m-1. MTV and SDmax were independent prognostic factors of PFS (all P < 0.001). Combined with MTV and SDmax, the patients were divided into three groups, and the difference of PFS among the groups was statistically significant (P < 0.001), and was able to stratify the risk of NCCN-IPI patients in the low-risk (NCCN-IPI < 4) and high-risk (NCCN-IPI ≥ 4) groups (P = 0.001 and P = 0.031). CONCLUSION: MTV and SDmax are independent prognostic factors for PFS in DCBCL patients, which describe tumor burden and tumor dissemination characteristics, respectively. The combination of the two could facilitate risk stratification between the low-risk and high-risk NCCN-IPI groups.

Microplastics alter nitrous oxide production and pathways through affecting microbiome in estuarine sediments.

Increasing microplastics (MPs) pollution in estuaries profoundly impacts microbial ecosystems and biogeochemical processes. Nitrous oxide (N2O), a powerful greenhouse gas, is an important intermediate product of microbial nitrogen cycling. However, how MPs regulate N2O production and its pathways remain poorly understood. Here, impacts of traditional petroleum-based and emerging biodegradable MPs on microbial N2O production and its pathways were studied through dual-isotope (15N-18O) labeling technique and molecular methods. Results indicated that both traditional petroleum-based and emerging biodegradable MPs promoted sedimentary N2O production, whereas pathways varied. Biodegradable polylactic acid (PLA) MPs displayed greater promotion of N2O production than petroleum-based MPs, polyvinyl chloride (PVC) and polyethylene (PE), of which PLA promoted through nitrifier nitrification (NN) and heterotrophic denitrification (HD), PE through nitrifier denitrification and HD, and PVC through NN. By combining the analysis of N2O production rates with sediment chemical and microbiological properties, we demonstrated that the enrichment of nitrifying and denitrifying bacteria, as well as related functional genes directly and/or indirectly increased N2O production primarily by interacting with carbon and nitrogen substrates. Different response of nitrogen cycling microbes to MPs led to the difference in N2O increase pathways, of which nitrifying bacteria significantly enriched in all MPs treatments due to the niches provided by MPs. However, part of denitrifying bacteria significantly enriched in treatments containing PLA and PE MPs, which may serve as organic carbon substrates. This work highlights that the presence of MPs can promote sedimentary N2O production, and the emerging biodegradable MPs represented by PLA may have a greater potential to enhance estuarine N2O emissions and accelerate global climate change.