Submucosal Enhancing Stripe as a Contrast Material-enhanced MRI-based Imaging Feature for the Differentiation of Stage T0-T1 from Early T2 Rectal Cancers.

Background Accurate differentiation of stage T0-T1 rectal tumors from stage T2 rectal tumors facilitates the selection of appropriate surgical treatment. MRI is a recommended technique for local staging, but its ability to distinguish T1 from T2 tumors is poor. Purpose To explore the value of a submucosal enhancing stripe (SES), an uninterrupted enhancing band between the rectal tumor and the muscular layer on contrast material-enhanced T1-weighted images, as a potential imaging feature to differentiate T0-T1 from T2 rectal tumors. Materials and Methods This retrospective study included patients with pT0-T1 and pT2 rectal tumors who underwent pretreatment MRI and rectal tumor resection between January 2012 and November 2019. Two radiologists independently evaluated tumor characteristics (SES; status of muscularis propria [SMP]; and tumor shape, location, and size) at MRI. The associations of clinical and imaging characteristics with stage T0-T1 or T2 tumors were assessed, ß values were calculated, and predictive models were built. The diagnostic accuracies for the differentiation of T0-T1 tumors from T2 tumors with SES and SMP were compared. Results Data from 431 patients (mean age, 60 years ± 10 [standard deviation]; 261 men) were evaluated. SES (ß = 3.9; 95% CI: 3.1, 4.7; P < .001), SMP (ß = 1.3; 95% CI: 0.7, 1.9; P < .001), and carpetlike shape (ß = 1.6; 95% CI: 0.5, 2.8; P = .01) were independent factors distinguishing T0-T1 tumors from T2 tumors. The diagnostic accuracy was 87% (95% CI: 84, 90; 376 of 431) for SES and 67% (95% CI: 63, 72; 290 of 431) for SMP (P < .001). Conclusion Submucosal enhancing stripe (SES) at contrasted-enhanced MRI, status of muscularis propria (SMP) on T2-weighted images, and tumor shape can serve as independent imaging features to differentiate stage T0-T1 rectal tumors from stage T2 rectal tumors. Moreover, SES is a more accurate feature than is SMP. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Turkbey in this issue.

The mitochondrial Na(+)/Ca(2+) exchanger may reduce high glucose-induced oxidative stress and nucleotide-binding oligomerization domain receptor 3 inflammasome activation in endothelial cells.

BACKGROUND: The mitochondrial Na(+)/Ca(2+) exchanger, NCLX, plays an important role in the balance between Ca(2+) influx and efflux across the mitochondrial inner membrane in endothelial cells. Mitochondrial metabolism is likely to be affected by the activity of NCLX because Ca(2+) activates several enzymes of the Krebs cycle. It is currently believed that mitochondria are not only centers of energy production but are also important sites of reactive oxygen species (ROS) generation and nucleotide-binding oligomerization domain receptor 3 (NLRP3) inflammasome activation. METHODS & RESULTS: This study focused on NCLX function, in rat aortic endothelial cells (RAECs), induced by glucose. First, we detected an increase in NCLX expression in the endothelia of rats with diabetes mellitus, which was induced by an injection of streptozotocin. Next, colocalization of NCLX expression and mitochondria was detected using confocal analysis. Suppression of NCLX expression, using an siRNA construct (siNCLX), enhanced mitochondrial Ca(2+) influx and blocked efflux induced by glucose. Unexpectedly, silencing of NCLX expression induced increased ROS generation and NLRP3 inflammasome activation. CONCLUSIONS: These findings suggest that NCLX affects glucose-dependent mitochondrial Ca(2+) signaling, thereby regulating ROS generation and NLRP3 inflammasome activation in high glucose conditions. In the early stages of high glucose stimulation, NCLX expression increases to compensate in order to self-protect mitochondrial maintenance, stability, and function in endothelial cells.

[Construction and Identification of Transgenic Strain of Toxoplasma gondii High-expressing Virulence Factor ROP18].

OBJECTIVE: To construct a transgenic strain of Toxoplasma gondii high-expressing ROP18. METHODS: The gene sequence of encoding ROP18 was amplified by RT-PCR with RNA of T. gondii RH strain. The purified PCR product was subcloned into pCR-Blunt II-Top vector to construct pROP18. The gene sequence of encoding ROP18 was amplified from pROP18, and subcloned into pTUB8-mycGFPPftail-Ty1. The recombinant plasmid pTUB8-ROP18-Ty1 was electroporated into T. gondii RH strain. Stable transgenic cells were selected in the presence of 25 µg/ml mycophenolic acid and 50 µg/ml xanthine, and parasite clones were isolated by limiting dilution after drug selection. The expression of ROP18 in transgenic parasites was detected by immunofluorescence analysis and Western blotting. Giemsa assay was used to detect the proliferation rate of RH strain and the transgenic strain of T. gondii high-expressing ROP18. Twenty mice were divided into two groups. Each mouse in RH strain group was intraperitoneally injected with 1 x 10(3) RH strain, and that of transgenic strain group received 1 x 10(3) transgenic high-expressing ROP18 strain. RESULTS: The full-length sequence of ROP18 gene (1,665 bp) was amplified by RT-PCR. The recombinant plasmid pTUB8-ROP18-Ty1 was identified by restriction enzyme digestion and sequencing methods. Western blotting analysis showed that the transgenic high-expressing ROP18 strain expressed ROP18-Ty1 (Mr 56,000). Immunofluorescence assay showed that ROP18-Ty1 was localized in the rhoptry of T. gondii. Giemsa assay confirmed that ROP18 protein enhanced the proliferation of T. gondii. On the 6th, 12th, and 24th hour after HFF cells infected with T. gondii, the number of tachyzoites in transgenic strain group was 100.0 ± 16.9, 476.0 ± 31.1, and 860.0 ± 52.3, respectively, higher than that of RH strain group (88.0 ± 16.9, 300.0 ± 11.3, 675.0 ± 35.4) (P < 0.05). In RH strain group, all the mice were survival on the 8th day post-infection, the survival rate on the 14th day was 30% (3/10), and all died on the 16th day. In transgenic strain group, all the mice were survival on the 5th day post-infection, the survival rate on the 8th day was 30% (3/10), and all died on the 9th day. CONCLUSION: The transgenic high-expressing ROP18 strain of T. gondii is constructed.