Ligand-Mediated Magnetism-Conversion Nanoprobes for Activatable Ultra-High Field Magnetic Resonance Imaging.

Ultra-high field (UHF) magnetic resonance imaging (MRI) has emerged as a focal point of interest in the field of cancer diagnosis. Despite the ability of current paramagnetic or superparamagnetic smart MRI contrast agents to selectively enhance tumor signals in low-field MRI, their effectiveness at UHF remains inadequate due to inherent magnetism. Here, we report a ligand-mediated magnetism-conversion nanoprobe (MCNP) composed of 3-mercaptopropionic acid ligand-coated silver-gadolinium bimetallic nanoparticles. The MCNP exhibits a pH-dependent magnetism conversion from ferromagnetism to diamagnetism, facilitating tunable nanomagnetism for pH-activatable UHF MRI. Under neutral pH, the thiolate (-S- ) ligands lead to short τ'm and increased magnetization of the MCNPs. Conversely, in the acidic tumor microenvironment, the thiolate ligands are protonated and transform into thiol (-SH) ligands, resulting in prolonged τ'm and decreased magnetization of the MCNP, thereby enhancing longitudinal relaxivity (r1) values at UHF MRI. Notably, under a 9 T MRI field, the pH-sensitive changes in Ag-S binding affinity of the MCNP lead to a remarkable (>10-fold) r1 increase in an acidic medium (pH 5.0). In vivo studies demonstrate the capability of MCNPs to amplify MRI signal of hepatic tumors, suggesting their potential as a next-generation UHF-tailored smart MRI contrast agent.

Enhanced efficacy of a novel aspirator in uniportal video-assisted thoracoscopic mediastinal lymph node dissection: a non-randomized prospective clinical trial.

Background: Video-assisted thoracoscopic surgery (VATS) is the standard approach in early-stage non-small cell lung cancer (NSCLC) and surgical aspirators play a crucial role. Traditional aspirators lack the ability to pull and lift tissue and cannot achieve optimal exposure. Therefore, we designed a new surgical aspirator that combined the function of thoracoscopic forceps. In this study, we aimed to validate the efficacy and safety of this new surgical aspirator. Methods: We performed a prospective non-randomized intervention trial and enrolled 504 consecutive patients scheduled for uniportal VATS in early NSCLC requiring mediastinal lymph node dissection. A novel aspirator we developed with a clamping function via a front pliers-like structure was implemented in intervention group, whereas traditional aspirator was used in control group. Time spent for nodal dissection in No. 2/4R and No. 7R/L (No. 7 lymph nodes resected through right or left side) lymph nodes and perioperative adverse events related to lymph node dissection were recorded. Mann-Whitey U test was applied to analyze sex and pathological type, an independent-samples t-test was applied to analyze surgery time and age. Results: In total, 250 of enrolled patients were allocated into traditional aspirator group and 254 of them were allocated into new aspirator group. Surgeons spent 544.71±120.80 (range, 332-917, median 541) seconds dissecting No. 2/4R lymph nodes with traditional aspirators and 507.54±100.00 (range, 348-702, median 520) seconds dissecting with new aspirators (P=0.008). The traditional aspirator group had an average surgery time of 507.11±104.61 (range, 310-785, median 510) seconds for No. 7R lymph nodes and 608.47±128.50 (range, 397-919, median 606) seconds for No. 7L lymph nodes, while that in the new aspirator group was 465.09±94.94 (range, 271-744, median 476) seconds (P=0.001) and 549.39±102.11 (range, 368-782, median 538) seconds (P<0.001). The new aspirator showed an efficacy advantage in mediastinal lymph node dissection in VATS, without additional risk. Conclusions: This is the first report about a new suction device combining the functions of both traditional surgical aspirators and forceps, which can effectively shorten the time of mediastinal lymph node dissection and improve the efficiency of thoracoscopic surgery without increasing lymph node dissection-related adverse events.

Intelligent Algorithm-Based Magnetic Resonance Imaging in Radical Gastrectomy under Laparoscope.

The study focused on the influence of intelligent algorithm-based magnetic resonance imaging (MRI) on short-term curative effects of laparoscopic radical gastrectomy for gastric cancer. A convolutional neural network- (CNN-) based algorithm was used to segment MRI images of patients with gastric cancer, and 158 subjects admitted at hospital were selected as research subjects and randomly divided into the 3D laparoscopy group and 2D laparoscopy group, with 79 cases in each group. The two groups were compared for operation time, intraoperative blood loss, number of dissected lymph nodes, exhaust time, time to get out of bed, postoperative hospital stay, and postoperative complications. The results showed that the CNN-based algorithm had high accuracy with clear contours. The similarity coefficient (DSC) was 0.89, the sensitivity was 0.93, and the average time to process an image was 1.1 min. The 3D laparoscopic group had shorter operation time (86.3 ± 21.0 min vs. 98 ± 23.3 min) and less intraoperative blood loss (200 ± 27.6 mL vs. 209 ± 29.8 mL) than the 2D laparoscopic group, and the difference was statistically significant (P < 0.05). The number of dissected lymph nodes was 38.4 ± 8.5 in the 3D group and 36.1 ± 6.0 in the 2D group, showing no statistically significant difference (P > 0.05). At the same time, no statistically significant difference was noted in postoperative exhaust time, time to get out of bed, postoperative hospital stay, and the incidence of complications (P > 0.05). It was concluded that the algorithm in this study can accurately segment the target area, providing a basis for the preoperative examination of gastric cancer, and that 3D laparoscopic surgery can shorten the operation time and reduce intraoperative bleeding, while achieving similar short-term curative effects to 2D laparoscopy.

[Establishment of a rabbit model of cardiopulmonary bypass in acute cerebral embolism phase].

OBJECTIVE: To establish a stable and feasible rabbit model of cardiopulmonary bypass (CPB) in acute cerebral embolism phase for studying the effects of CPB on brain tissues and the timing of surgical intervention of acute cerebral embolism. METHODS: Fifty-four rabbits were randomized into group A (n=18) to receive CPB without middle cerebral artery occlusion (MCAO) and group B to undergo CPB at 24 h (group B1, n=18) or 1 week (group B2, n=18) after MCAO. Through a supraorbital margin approach, electrocoagulation was carried out to occlude the main stem of the left MCA under direct vision to establish MCAO. Magnetic resonance imaging (MRI) was performed at both 24 h and 1 week after MCAO, and the severity of cerebral embolization was evaluated. CPB was established by cannulation of the ascending aorta and the right atrium through a median sternotomy incision. MRI was performed at 2 h after CPB to observe the brain tissues. RESULTS: MCAO was successfully established in groups B1 and B2, and all the rabbits survived after MCAO. In both groups A and B, MRI examination detected no cerebral hemorrhage or new embolism 2 h after CPB. CONCLUSIONS: We have established a stable and feasible CPB model in rabbits with acute cerebral embolism to allow study of the mechanisms of CPB-related organ damage and its interventions.