1.Early outcomes of robot-assisted subxiphoid approach and intercostal approach for anterior mediastinal tumors: A retrospective cohort study
Weiqiang ZENG ; Haili DANG ; Lifei WANG ; Zhen PENG ; Xiangdou BAI ; Bing WANG ; Xiaoyang HE ; Dacheng JIN ; Yunjiu GOU
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(03):369-375
Objective To compare the clinical outcomes of subxiphoid robot-assisted thoracoscopic surgery (SRATS) and intercostal robot-assisted thoracoscopic surgery (IRATS) in the treatment of anterior mediastinal tumors. Methods A retrospective analysis was conducted on patients with anterior mediastinal tumors who underwent robot-assisted surgery in the Department of Thoracic Surgery, Gansu Provincial Hospital, from May 2020 to July 2022. According to the surgical approach, patients were divided into an SRATS group and an IRATS group. Perioperative data were compared between the two groups. Results A total of 87 patients were included. There were 41 patients in the SRATS group [23 males, 18 females; mean age, (44.51±11.28) years] and 46 patients in the IRATS group [21 males, 25 females; mean age, (46.67±8.76) years]. Compared with the IRATS group, the SRATS group had significantly less intraoperative blood loss [(24.41±6.67) mL vs. (37.93±9.23) mL, P<0.001], shorter postoperative drainage duration [(1.73±0.59) days vs. (2.54±0.50) days, P<0.001], lower postoperative drainage volume [(94.46±34.08) mLvs. (116.72±24.90) mL, P=0.001], lower visual analogue scale (VAS) pain scores on postoperative day 1 [(3.66±0.76) points vs. (4.15±0.84) points, P=0.005] and day 3 [(2.41±0.59) points vs. (2.89±0.82) points, P=0.003], shorter postoperative hospital stay [(4.12±0.81) days vs. (4.98±1.02) days, P<0.001], and lower hospitalization costs [(4.51±0.65) ten thousand yuan vs. (4.86±0.68) ten thousand yuan, P=0.020]. There were no statistical differences between the two groups in operative time or incidence of postoperative complications (P>0.05). Conclusion Both SRATS and IRATS are safe and effective for the treatment of anterior mediastinal tumors. However, SRATS is less invasive and more conducive to enhanced postoperative recovery.
2.Compact Fundus Imaging System Using Shack-Hartmann Wavefront Sensing for High-speed Auto-focus
Zhe-Kai LIN ; Long CHEN ; Geng-Yong ZHENG ; Jin-Tian HUANG ; Jia-Xin DONG ; Shang-Pan YANG ; Wen-Zheng DING ; Ding-An HAN ; Xue-Hua WANG ; Ya-Guang ZENG
Progress in Biochemistry and Biophysics 2026;53(4):1076-1086
ObjectiveThe widespread adoption of portable fundus cameras for primary care and community screening is hindered by limitations in current autofocus(AF) technologies. Image-based methods relying on sharpness evaluation require iterative searches, resulting in slow convergence, while projection-based techniques are susceptible to optical artifacts and calibration errors. To address these challenges, this study introduces a novel AF system based on direct wavefront sensing, designed to deliver simultaneous high speed, high precision, and operational robustness within the compact form factor essential for portable ophthalmic devices. MethodsOur approach fundamentally reimagines the AF process by directly measuring the ocular wavefront aberration. We developed a custom portable fundus camera integrating a miniaturized Shack-Hartmann wavefront sensor (SHWS) into the optical path. An 850 nm laser diode projects a point source onto the retina via oblique illumination to minimize corneal reflections. Light scattered from this spot carries the eye’s refractive error through the imaging optics and is directed to the SHWS, positioned at a plane optically conjugate to the primary color CMOS imaging sensor. A microlens array within the SHWS samples the incident wavefront, generating a pattern of focal spots on a CCD. Real-time centroid analysis of these spots provides a map of local wavefront slopes. These measurements are processed through a singular value decomposition (SVD) algorithm to fit a Zernike polynomial basis set, enabling real-time reconstruction of the wavefront phase. The defocus component (S) is extracted from the second-order Zernike coefficients, providing a direct, quantitative measure of the refractive error in diopters. This value serves as a precise error signal in a closed-loop control system, which commands a voice-coil actuated focusing lens to its null position in a single, deterministic step, eliminating the need for iterative search algorithms. ResultsComprehensive evaluation demonstrated the system’s high performance. Testing on a calibrated model eye (OEMI-7) established a highly linear relationship between the computed defocus S and the focusing lens position across a ±20 Diopter (D) compensation range, achievable within a 5 mm mechanical travel. The system achieved a focusing precision of 0.08 D, corresponding to an 18-fold improvement over a conventional projection spot-size method tested under identical conditions. The total focus acquisition time, encompassing wavefront measurement, computation, and lens actuation, averaged under 0.5 s. Clinical validation with 25 human volunteers (50 eyes, refractive range -15 D to +10 D) confirmed practical efficacy. The wavefront-sensing AF succeeded in 92% of attempts with a mean time of 0.5 s, substantially outperforming a projection-based benchmark which achieved only a 32% success rate with an average time of 4.25 s. The system provided instantaneous directional guidance and maintained stability during minor ocular movements. Objective assessment of image quality, via amplitude contrast of retinal vasculature, showed consistent and significant enhancement following AF correction across the entire tested diopter range. ConclusionThis work successfully implements and validates a direct wavefront-sensing autofocus paradigm for portable fundus cameras. By directly quantifying and compensating for the optical defocus aberration, this method bypasses the fundamental limitations of image-processing and projection-based techniques, enabling rapid, precise, and deterministic diopter compensation. The developed system delivers an exceptional combination of a wide operational range (±20 D), high accuracy (0.08 D), fast convergence (0.5 s), and a compact physical footprint. This technology provides a practical and high-performance focusing solution capable of enhancing the reliability, throughput, and diagnostic utility of portable retinal imaging in large-scale screening applications. Future efforts will be directed towards system cost optimization and performance adaptation for diverse ocular conditions.
3.Network meta-analysis of the efficacy of GLP-1 receptor agonists in the treatment of type 2 diabetes mellitus complicated with obesity/overweight
Jin ZENG ; Juliang CHEN ; Ziwei HU ; Liangran YAO ; Yakun ZHAN
China Pharmacy 2026;37(10):1357-1363
OBJECTIVE To systematically evaluate the efficacy and safety of 6 kinds of GLP-1RAs in the treatment of type 2 diabetes mellitus (T2DM) patients with overweight or obesity, and to provide evidence-based reference for clinical practice. METHODS A comprehensive search was conducted in PubMed, Embase, Web of Science, the Cochrane Library, CNKI, VIP, Wanfang Data, and CBM from the inception to December 1, 2025. Randomized controlled trials (RCTs) were screened according to inclusion and exclusion criteria. Data extraction and risk of bias assessment were performed on the included studies. Network meta-analysis was conducted using Stata 17.0 software. RESULTS A total of 29 eligible RCTs were included, involving 7 404 patients. Six GLP-1RAs were evaluated: semaglutide, liraglutide, exenatide, dulaglutide, polyethylene glycol loxenatide, and beinaglutide. In terms of glycemic control, semaglutide had the highest probability of ranking first in reducing glycated hemoglobin (HbA1c) and fasting plasma glucose levels, followed by polyethylene glycol loxenatide. In terms of weight management, semaglutide showed the highest probability of ranking first, followed by liraglutide and exenatide. Regarding safety, dulaglutide had the highest probability of ranking first in reducing the incidence of gastrointestinal adverse events; none of the GLP-1RAs significantly increased the risk of severe hypoglycemia. Subgroup analysis revealed that liraglutide 1.8 mg, qd and exenatide extend-release 2.0 mg, qw demonstrated superior efficacy in reducing HbA1c and body weight compared with other doses/dosage forms of the same agents. CONCLUSIONS For T2DM patients with overweight or obesity, semaglutide offers the greatest benefits in glycemic control and weight reduction, while dulaglutide demonstrates superior gastrointestinal tolerability. Liraglutide 1.8 mg, qd and exenatide extend-release 2.0 mg, qw show relatively better overall efficacy in glycemic control and weight reduction among the same agents.
4.Effects of vigilance pedal position and route scenarios on lower extremity muscle load and gaze-tracking behavior in high-speed train simulated driving
Siyi ZENG ; Huishuan WU ; Ruihan ZHANG ; Chunhao XU ; Kezhi JIN
Journal of Environmental and Occupational Medicine 2026;43(5):542-549
Background High-speed train engineers' lower extremities are constrained by compulsive vigilance pedal tasks and limited space beneath the control console during driving. Shifts in alertness triggered by running route observation may share the same mental resource required by moderate-to-low physical exertion. Current research on improving cab design and maintaining optimal on-duty attention allocation remains limited. Objective To examine variations in lower extremity muscle load, gaze-tracking behavior, and driving performance under various combinations of vigilance pedal positions and route scenarios during simulated high-speed train tasks. To identify optimal working condition combinations that promote level and variety of physical activity and facilitate rational attention allocation. Methods A 4×2 within-subjects design were employed (4 vigilance pedal position profiles: knee front, side, and any; 2 route scenarios: monotonous and complex). Nine male college volunteers were recruited as simulated drivers to perform designated interval driving tasks. Surface electromyography and eye tracking were used to assess leg muscle load and gaze behavior respectively. Task performance and subjective fatigue were recorded. Results In all simulation driving tasks, skeletal muscle loads were low with the percentage of maximum voluntary contraction (%MVC) at approximately 4%. No fatigue tendencies were observed within single trial blocks (7 min), and the subjective fatigue ratings remained relatively low. While the activation of the dominant-side tibialis anterior was higher for the knee pedal than for the front (%MVC: 3.7% ± 3.13% vs. 1.08% ± 0.72%) or the side pedals (%MVC: 3.7% ± 3.13% vs. 1.4% ± 0.77%). The activation level of the dominant-side gastrocnemius was higher for the knee pedal than for the other three pedal profiles. For the any pedal condition, the intercept of the instantaneous median frequency curve for the dominant-side rectus femoris was lower in the monotonous route than in the complex route [(111.18 ± 35.78) Hz vs. (153.33 ± 39.12) Hz]. Among eye-tracking metrics, total fixations were higher during knee-level pedaling than side pedaling, while more saccades were recorded in monotonous routes than in complex ones. Regarding task performance, the any pedal yielded fewer missed signals than the front pedal, with 2/3 and 1/3 of participants preferring the front and knee pedals, respectively. The activation levels of the dominant tibialis anterior and dominant gastrocnemius muscles during the knee pedal × complex route combination were higher than any combination involving the front pedal. No statistically significant effect of pedal position or route scenario was found on other indicators. Conclusion The combination of knee pedal and complex route provides an optimal working setting for maximizing leg muscle mobility without compromising attention allocation or driving performance. It is recommended that train engineers modulate attention during monotonous routes to avoid emotional tension and increased muscle strain caused by over-monitoring. Given the ergonomic characteristics of high cognitive load, low physical exertion levels, and highly restricted lower limb mobility among high-speed train engineers, future cab designs should consider incorporating knee-level vigilance pedal and adjust safety alertness rules to allow reset via either front or knee pedal.
5.Effects of vigilance pedal position and route scenarios on lower extremity muscle load and gaze-tracking behavior in high-speed train simulated driving
Siyi ZENG ; Huishuan WU ; Ruihan ZHANG ; Chunhao XU ; Kezhi JIN
Journal of Environmental and Occupational Medicine 2026;43(5):542-549
Background High-speed train engineers' lower extremities are constrained by compulsive vigilance pedal tasks and limited space beneath the control console during driving. Shifts in alertness triggered by running route observation may share the same mental resource required by moderate-to-low physical exertion. Current research on improving cab design and maintaining optimal on-duty attention allocation remains limited. Objective To examine variations in lower extremity muscle load, gaze-tracking behavior, and driving performance under various combinations of vigilance pedal positions and route scenarios during simulated high-speed train tasks. To identify optimal working condition combinations that promote level and variety of physical activity and facilitate rational attention allocation. Methods A 4×2 within-subjects design were employed (4 vigilance pedal position profiles: knee front, side, and any; 2 route scenarios: monotonous and complex). Nine male college volunteers were recruited as simulated drivers to perform designated interval driving tasks. Surface electromyography and eye tracking were used to assess leg muscle load and gaze behavior respectively. Task performance and subjective fatigue were recorded. Results In all simulation driving tasks, skeletal muscle loads were low with the percentage of maximum voluntary contraction (%MVC) at approximately 4%. No fatigue tendencies were observed within single trial blocks (7 min), and the subjective fatigue ratings remained relatively low. While the activation of the dominant-side tibialis anterior was higher for the knee pedal than for the front (%MVC: 3.7% ± 3.13% vs. 1.08% ± 0.72%) or the side pedals (%MVC: 3.7% ± 3.13% vs. 1.4% ± 0.77%). The activation level of the dominant-side gastrocnemius was higher for the knee pedal than for the other three pedal profiles. For the any pedal condition, the intercept of the instantaneous median frequency curve for the dominant-side rectus femoris was lower in the monotonous route than in the complex route [(111.18 ± 35.78) Hz vs. (153.33 ± 39.12) Hz]. Among eye-tracking metrics, total fixations were higher during knee-level pedaling than side pedaling, while more saccades were recorded in monotonous routes than in complex ones. Regarding task performance, the any pedal yielded fewer missed signals than the front pedal, with 2/3 and 1/3 of participants preferring the front and knee pedals, respectively. The activation levels of the dominant tibialis anterior and dominant gastrocnemius muscles during the knee pedal × complex route combination were higher than any combination involving the front pedal. No statistically significant effect of pedal position or route scenario was found on other indicators. Conclusion The combination of knee pedal and complex route provides an optimal working setting for maximizing leg muscle mobility without compromising attention allocation or driving performance. It is recommended that train engineers modulate attention during monotonous routes to avoid emotional tension and increased muscle strain caused by over-monitoring. Given the ergonomic characteristics of high cognitive load, low physical exertion levels, and highly restricted lower limb mobility among high-speed train engineers, future cab designs should consider incorporating knee-level vigilance pedal and adjust safety alertness rules to allow reset via either front or knee pedal.
6.Dissecting antibody-mediated natural killer cell effects reveals a cytotoxic CX3CR1+KLRC2–CD16hi subset linked to hepatitis B virus outcomes
Libo TANG ; Yuhao WANG ; Zihan JIN ; Yurong GU ; Zhaofeng ZENG ; Linnan SONG ; Xuan YI ; Lingtao ZHANG ; Yujing ZHANG ; Weiying HE ; Liping WANG ; Weixin HE ; Jianru SUN ; Xiaoqin LAN ; Xiangyong LI ; Shihong ZHONG ; Yongyin LI
Clinical and Molecular Hepatology 2026;32(2):683-705
Background/Aims:
Natural killer (NK) cell function is generally considered dampened in chronic hepatitis B virus (HBV) infection; however, the NK cell pool exhibits phenotypic and functional heterogeneity, and the antibody--mediated effect of NK cells remains less characterized. This study evaluated the dynamic changes in antibody-mediated NK cell responses and the involvement of distinct NK subsets across disease stages and during antiviral treatment.
Methods:
A T-cell receptor-like antibody specific for the HBV core 18–27 peptide (cTCRL-Ab) was used to determine the antibody-mediated effect of NK cells, and an array of NK cell surface markers were analyzed in cross-sectional and longitudinal cohorts of patients with chronic HBV infection. Single-cell RNA sequencing (scRNA-seq) was performed to identify the heterogeneity of NK subsets.
Results:
The cTCRL-Ab enabled the detection of NK cell cytolytic activity and IFNγ production. Notably, cTCRL-Ab-mediated NK cell responses were compromised in chronically HBV-infected patients, particularly in those receiving pegylated interferon-α (Peg-IFNα), which was associated with the downregulation of CD16 expression. Correspondingly, Peg-IFNα inhibited cTCRL-Ab-mediated NK cell function by reducing CD16 expression in vitro. scRNA-seq revealed that CD16 downregulation occurred mainly within a dysfunctional CD16hi NK subset exhibiting exhaustion properties. In contrast, an activated CD16hiNK subpopulation (CX3CR1⁺KLRC2–CD16hi) with high cytotoxicity was enriched in patients who experienced favorable treatment responses. Furthermore, the intrahepatic CX3CR1+KLRC2–CD16hi subset tended to exhibit functional restoration in HBsAg-loss individuals.
Conclusions
Our data contribute to the understanding of antibody-mediated responses of NK cells in chronic HBV infection, and highlight a previously unappreciated functional CX3CR1+KLRC2–CD16hiNK subset as a potential therapeutic target.
7.Expert consensus on a stepwise strategy for the surgical management of empyema based on pathological staging (2026 edition)
Jichen QU ; Yunjiu GOU ; Guangyu CHEN ; Yongfu ZHAI ; Tinglong MA ; Xiaogang ZENG ; Feng JIN ; Yanzheng SONG ; Boxiong XIE ; Minjie MA ; Bin LI ; Jiang FAN
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(07):988-998
The surgical management of empyema (excluding those caused by mycobacterium tuberculosis and non-tuberculous mycobacteria) is rapidly evolving towards minimally invasive, precise, and stepwise approaches. The traditional three-stage classification (exudative, fibrinopurulent, and organizing) has limitations in guiding dynamic clinical decision-making. For the first time, this consensus explicitly identifies two critical junctures in the pathological progression of empyema: "early transformation" (stage Ⅰ to Ⅱ) and "late transformation" (stage Ⅱ to Ⅲ), and thereby constructs a corresponding "identification-early warning-intervention" stepwise therapeutic framework. The consensus emphasizes that proactive debridement via video-assisted thoracoscopic surgery should be performed during the early transformation phase to halt disease progression. Conversely, during the late transformation phase, therapeutic goals should be rationally adjusted to prioritize adequate drainage, avoiding futile pleural decortication. Moreover, the consensus underscores the pivotal role of precise perioperative etiological diagnosis (e.g. metagenomic nest-generation sequencing) and standardized anti-infective therapy. Integrating practical experiences from multiple thoracic surgery centers in China and relevant evidence-based literature, this consensus formulates recommendations on the precise definitions of staging, surgical indications for each phase, key technical points, perioperative management, and training systems. It aims to promote the standardized and individualized surgical management of empyema, ultimately optimizing patient prognosis.
8.A clinical study on the prognostic value of preoperative prognostic nutritional index in patients with renal cell carcinoma undergoing partial nephrectomy
Yishuai ZHANG ; Yanxin ZHUANG ; BAOERBIEKE YELINAER ; Ying WANG ; Chenhui MA ; Jin ZENG ; Xinqi PEI
Journal of Modern Urology 2026;31(5):428-434
Objective To investigate the clinical prognostic value of the prognostic nutritional index (PNI) in patients with renal cell carcinoma (RCC) undergoing partial nephrectomy.Methods A retrospective analysis was conducted on the clinical data of RCC patients who underwent partial nephrectomy at our hospital during 2020 and 2024.The optimal cutoff value of PNI was determined based on the maximum Youden index from the receiver operating characteristic (ROC) curve.The clinicopathological characteristics, overall survival (OS), and progression-free survival (PFS) between patients with different PNI levels were compared.Cox regression analysis was used to explore the independent prognostic factors for RCC patients. Results Based on the ROC curve, the optimal cutoff value corresponding to the maximum Youden index was calculated to be 46.675, at which point the sensitivity was 65.3% and the specificity was 62.2%.Of the 815 patients included in the study, 293 (36.0%) patients had a PNI<46.675.Cox regression analysis confirmed that preoperative PNI, tumor diameter, ISUP classification, and ECOG score were independent risk factors for postoperative OS in patients with RCC who underwent PN (P<0.05).In addition, preoperative PNI, tumor diameter, ISUP classification and ECOG score were independent risk factors for postoperative PFS (P<0.05).After covariates in the multivariable Cox regression model were adjusted, patients in the low PNI group demonstrated significantly shorter overall survival (HR=2.392, P<0.001) and significantly poorer progression-free survival (HR=2.076, P<0.001) compared to those in the high PNI group.Conclusion Preoperative PNI has significant clinical value in evaluating the prognosis of RCC patients undergoing partial nephrectomy.An elevated preoperative PNI is associated with a better prognosis.
9.Proteomic Profiling of Qi-blood Deficiency vs Damp-heat Syndrome in Colorectal Cancer: Therapeutic Targeting by Astragaloside IV-berberine
Zhao-Huan LI ; Jing-Wen ZHAO ; Xin ZHANG ; Jian-Jin GUO ; Jie XU ; Zeng-Qiang YANG ; Hao TU ; Min ZOU ; Ming-Bin GUI ; Feng GAO
Progress in Biochemistry and Biophysics 2026;53(9):2462-2479
ObjectiveColorectal cancer (CRC) is a highly heterogeneous malignancy, and traditional Chinese medicine (TCM) syndrome differentiation is widely used in its clinical management. However, the biological basis underlying different TCM syndromes remains insufficiently understood. This study aimed to investigate the proteomic differences between qi-blood deficiency syndrome (QBDS) and damp-heat syndrome (DHS) in CRC patients and to establish a “syndrome-differential protein-herbal component” network for exploring potential molecular mechanisms and therapeutic targets associated with syndrome-specific treatment strategies. MethodsTumor tissue samples were collected from 10 patients with pathologically confirmed CRC, including 5 patients diagnosed with QBDS and 5 with DHS according to standardized TCM syndrome differentiation criteria. Tandem mass tag (TMT)-based quantitative proteomics was employed to identify differentially expressed proteins (DEPs) between the two syndrome groups. Functional enrichment analyses, including Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, were performed to characterize the biological functions and signaling pathways associated with the identified DEPs. Least absolute shrinkage and selection operator (LASSO) regression analysis was further applied to screen key syndrome-related proteins and construct a core protein prediction model. Subsequently, molecular docking was conducted to evaluate the binding affinities between representative herbal compounds, astragaloside IV and berberine, and the identified core proteins. Finally, cell counting kit-8 (CCK-8) assays were performed in HCT 116 and HT-29 colorectal cancer cell lines to validate the anti-proliferative activities of these compounds in vitro. ResultsA total of 44 DEPs were identified between QBDS and DHS tissues, including 21 upregulated and 23 downregulated proteins in the QBDS group relative to the DHS group. Functional enrichment analyses revealed that these proteins were primarily associated with antiviral immune responses, regulation of inflammatory signaling, NF‑κB signaling pathways, cholesterol metabolism, and other biological processes relevant to tumor progression and host immune regulation. LASSO regression analysis identified eight core proteins with potential syndrome-specific significance. Among them, ST7, GPCPD1, and PODXL were closely associated with QBDS, whereas FAT1, GRB7, KRT7, MAFF, and MMP8 were associated with DHS. Molecular docking demonstrated favorable interactions between astragaloside IV and QBDS-related proteins, with binding energies lower than -5 kcal/mol, indicating stable binding activity. Berberine exhibited even lower binding energies and stronger binding specificity toward DHS-related core proteins. In vitro experiments further confirmed that both compounds inhibited CRC cell proliferation, while berberine displayed significantly greater anti-proliferative efficacy. The lowest 48 h IC50 value of berberine reached 15.21 mg/L in CRC cells, indicating a stronger growth-inhibitory effect than astragaloside IV. ConclusionCRC patients with QBDS and DHS exhibit distinct proteomic characteristics, suggesting that different TCM syndromes possess unique molecular signatures. The identified core proteins may serve as potential biomarkers for syndrome differentiation, while astragaloside IV and berberine may exert therapeutic effects through targeting syndrome-specific molecular networks. These findings provide preliminary proteomic evidence supporting syndrome-guided precision integrative medicine in CRC and offer new insights into the biological basis of TCM syndrome differentiation and individualized therapeutic strategies.
10.Application of Carbon Nanoparticle-Manganese Dioxide Injection in Gastrointestinal Staining-Based Marking and Localization in Rats and Pigs
Wanlin CHEN ; Qingrui DONG ; Mengtao LI ; Nan LIN ; Hu ZHAO ; Zaizhong ZHANG ; Lingjun ZENG ; Pei LI ; Jin YANG ; Yu WANG ; Aiwen HUANG
Laboratory Animal and Comparative Medicine 2026;46(5):727-739
ObjectiveTo develop a carbon nanoparticle-manganese dioxide (CN-MnO2) injection integrating visually identifiable staining and magnetic resonance (MR) T1/T2 dual-modal imaging, and to systematically evaluate its physicochemical properties, critical quality attributes, biocompatibility, and efficacy for gastrointestinal marking and localization. MethodsCN-MnO2 was prepared using a mild liquid-phase in situ redox deposition strategy and characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential analysis, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The pH of CN-MnO2 was directly measured using a pH meter. The osmolality pressure of CN-MnO2 was determined by the freezing point depression method. The bacterial endotoxin was detected using the gel-clot Limulus amebocyte lysate test, which did not rely on absorbance readings. The appearance of the CN-MnO2 injection solution stored at 4 ℃ under light shielding and sealed for 0, 5, and 10 days was observed, and its hydrated particle size, polydispersity index, zeta potential, and pH were also measured. With gadopentetate dimeglumine (Gd-DTPA) as the positive control, different concentration gradients were established, and T1 and T2 relaxation times were measured to construct concentration-dependent plots of the longitudinal and transverse relaxation rates (R1 and R2) and calculate the corresponding relaxivities (r1 and r2), compare relaxivity performance, and determine the working concentration for subsequent in vivo experiments. Cytocompatibility was assessed using the methyl thiazolyl tetrazolium (MTT) assay and live/dead staining. Sixteen male 6-week-old SD rats were randomly assigned to an experimental group and a control group (n=8 per group) and subcutaneously injected with CN-MnO2 injection at a total Mn concentration of 0.80 mmol/L or an equal volume of normal saline, respectively. Short-term in vivo safety was evaluated by regular body weight monitoring, hematoxylin-eosin (HE) staining of major organs, hematological and serum biochemical analyses, inflammatory cytokine detection, and inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. Eight male 5–6-month-old Bama minipigs were randomly assigned to a CN-MnO2 group (n=6) and a carbon nanoparticle suspension injection (CNSI) group (n=2). CN-MnO2 injection or CNSI was injected subserosally into the stomach, small intestine, and colon. Within 5 min after each injection, the maximum staining diameter at each injection site was measured and recorded. MR T1WI/T2WI scans were performed on days 3 and 7 after injection to evaluate MR visualization at the injection sites. At the end of observation, the injection sites and major organs were collected for histopathological evaluation by hematoxylin-eosin staining. ResultsCN-MnO2 appeared as a black suspension, with no obvious aggregation or sedimentation after standing at room temperature (20-25 ℃) for 15 days. Its average hydrodynamic diameter was approximately (228.7±15.3) nm, the polydispersity index was 0.184±0.021, and the zeta potential was (-24.6±2.8) mV. XPS showed that CN-MnO2 was mainly composed of C, O, and Mn, with oxygen accounting for approximately 68.82%. The Mn 2p spectrum exhibited two characteristic peaks at 642.4 and 653.1 eV. XRD indicated that low-crystallinity δ-MnO2 was dispersed within the carbon matrix. The pH was 6.82±0.06, the osmolality was (298.4±6.7) mOsm/kg, and the bacterial endotoxin level was below the detection limit. In vitro MR imaging showed a clear concentration-dependent response, with r1 and r2 values of 9.6 L·mmol-1·s-1 and 17.2 L·mmol-1·s-1, respectively, indicating favorable T1/T2 contrast performance superior to that of Gd-DTPA. At 0.80 mmol/L, CN-MnO2 showed no obvious cytotoxicity in vitro. Short-term safety evaluation in SD rats revealed no obvious inflammatory response, impairment of liver or renal function, or abnormal manganese accumulation in major organs. In Bama minipigs, the mean staining diameters of the CN-MnO2 group in the stomach, small intestine, and colon were (0.65±0.12) cm, (0.61±0.11) cm, and (0.58±0.10) cm, respectively, with no significant difference among the three injection sites (P>0.05). The overall mean staining diameter was smaller in the CN-MnO2 group than in the CNSI group (P<0.05). MR examinations showed that the injection sites were identifiable on both day 3 and day 7, with stronger signals observed on day 3. At the end of observation, no obvious pathological abnormalities were observed at the injection sites or in major organs. ConclusionA CN-MnO2 injection with uniform particle size and stable physicochemical properties can be successfully prepared. This formulation integrates visible gastrointestinal staining with MR T1/T2 dual-modal imaging, providing a new strategy for preoperative gastrointestinal marking and localization as well as precise intraoperative resection.

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