Protocol for identifying immune checkpoint on circulating tumor cells of human pancreatic ductal adenocarcinoma by single-cell RNA sequencing.

Circulating tumor cells (CTCs) are regarded as the "seeds" of tumor metastasis. Identifying immune checkpoints on CTCs is essential for establishing efficient immunotherapies to prevent tumor metastasis. Here, we present a protocol for isolating CTCs and obtaining single-cell suspensions from pancreatic ductal adenocarcinoma liver metastatic patients. We describe steps for biospecimen acquisition, CTC isolation, and tissue dissociation. We then detail procedures for performing single-cell RNA-seq, annotating cell types, and identifying immune checkpoints on CTCs. For complete details on the use and execution of this protocol, please refer to Liu et al. (2023).1.

A novel D-ring modified taxoid: synthesis and biological evaluation of a γ-lactone analogue of docetaxel.

The synthesis of a novel D-ring modified docetaxel analogue, in which the oxetane ring is replaced with a γ-lactone, was achieved from 10-deacetylbaccatin III. The key steps of the synthesis include the direct acetylation of the secondary hydroxyl group at C-5 and D-ring opening and intramolecular aldol reaction to form the γ-lactone. In MTT assays, this analogue proved to have equipotent cytotoxicity relative to paclitaxel towards HCT8, HePG2 and BGC23 cancer cell lines, and be more potent than paclitaxel against A549 and A375. It represents the first example of D-ring modified taxoids with significant cytotoxicity.

Which is the preferred revision technique for loosened iliac screw? A novel technique of boring cement injection from the outer cortical shell.

STUDY DESIGN: An in vitro biomechanical cadaver study. OBJECTIVES: To evaluate the pull-out strength after 5000 cyclic loading among 4 revision techniques for the loosened iliac screw using corticocancellous bone, longer screw, traditional cement augmentation, and boring cement augmentation. SUMMARY OF BACKGROUND DATA: Iliac screw loosening is still a clinical problem for lumbo-iliac fusion. Although many revision techniques using corticocancellous bone, larger screw, and polymethylmethacrylate (PMMA) augmentation were applied in repairing pedicle screw loosening, their biomechanical effects on the loosened iliac screw remain undetermined. METHODS: Eight fresh human cadaver pelvises with the bone mineral density values ranging from 0.83 to 0.97 g/cm were adopted in this study. After testing the primary screw of 7.5 mm diameter and 70 mm length, 4 revision techniques were sequentially established and tested on the same pelvis as follows: corticocancellous bone, longer screw with 100 mm length, traditional PMMA augmentation, and boring PMMA augmentation. The difference of the boring technique from traditional PMMA augmentation is that PMMA was injected into the screw tract through 3 boring holes of outer cortical shell without removing the screw. On an MTS machine, after 5000 cyclic compressive loading of -200∼-500 N to the screw head, axial maximum pull-out strengths of the 5 screws were measured and analyzed. RESULTS: The pull-out strengths of the primary screw and 4 revised screws with corticocancellous bone, longer screw and traditional and boring PMMA augmentation were 1167 N, 361 N, 854 N, 1954 N, and 1820 N, respectively. Although longer screw method obtained significantly higher pull-out strength than corticocancellous bone (P<0.05), the revised screws using these 2 techniques exhibited notably lower pull-out strength than the primary screw and 2 PMMA-augmented screws (P<0.05). Either traditional or boring PMMA screw showed obviously higher pull-out strength than the primary screw (P<0.05); however, no significant difference of pull-out strength was detected between the 2 PMMA screws (P>0.05). CONCLUSIONS: Wadding corticocancellous bone and increasing screw length failed to provide sufficient anchoring strength for a loosened iliac screw; however, both traditional and boring PMMA-augmented techniques could effectively increase the fixation strength. On the basis of the viewpoint of minimal invasion, the boring PMMA augmentation may serve as a suitable salvage technique for iliac screw loosening.

5-Benzyl-7-methyl-hexa-hydro-3a,7-methano-1H-furo[3,4-c]azocine-3,10(4H)-dione.

The title compound, C(18)H(21)NO(3), was obtained via a double Mannich condensation reaction of 6-methyl-tetra-hydro-isobenzofuran-1,7(3H,7aH)-dione with formaldehyde and benzyl-amine. The mol-ecule contains three fused rings of which the cyclo-hexa-none and piperidine rings adopt chair conformations and the furan-one ring assumes an envelope conformation. An inter-molecular C-H⋯π inter-action is present in the crystal structure.