Establishment of a multifunctional impact system and a study of a pancreatic trauma model in rats based on controlling the injury area.

Background: At present, basic scientific research on pancreatic trauma is rare due to the lack of ideal animal models and modeling equipment for pancreatic trauma. Therefore, we intend to develop a multifunctional impact system with simple operation, diverse impact and accurate measurement and to establish a rat pancreatic trauma model based on injury area control by using the system. Methods: The impactor was designed based on the convenience of the impact energy acquisition, the diversity of the impact operation, and the precision of the impact strength parameter measurement by the team. The efficacy and stability/repeatability of the impactor were preliminarily evaluated. An impact head with different impact areas (3 cm2 and 6 cm2) of the impactor was used to squeeze the rat pancreas in the abdomen to form different injury areas under a pressure of 400 kPa. The efficacy features of this trauma model were evaluated by detecting the outcomes of pathology and biochemistry at 24 h after injury in the two groups. Furthermore, these changes were also evaluated at 6 h, 24 h, 48 h and 72 h after injury in the 3 cm2 trauma group. Result: Multifunctional impactors were successfully explored. The impact force was continuously adjustable with a range of 0-200 kg. The compression and extrusion stress ranges were continuously adjustable from 0 to 100 kg. System adjustment verified that the impactor had fine efficacy (P < 0.05) and stability/repeatability (P > 0.05). Compared with the control group, rats in the pancreatic trauma group with different injury areas exhibited obvious injuries (P < 0.05), and compared with the 3 cm2 trauma group, the 6 cm2 trauma group exhibited the more severe injury (P < 0.05). After modeling, the injury characteristics at different time points showed stable differences(P < 0.05). Conclusions: A rat pancreatic trauma model based on injury area control was successfully established using the impactor developed in this study. This model is simple, effective, controllable, and suitable for animal experimental research on pancreatic trauma.

Clinical features and diagnostic approaches for abdominal tuberculosis: five-year experience from a non-tuberculosis-designated hospital in China.

BACKGROUND AND PURPOSE: abdominal tuberculosis (TB) is a common form of extrapulmonary TB but it is still a diagnostic dilemma in clinical practice. This study aimed to highlight the clinical features and diagnostic approaches for abdominal TB. METHODS: seventy cases of diagnosed abdominal TB were retrospectively collected between August 1st, 2015 and June 30th, 2020. They were classified as peritoneal TB, lymph node TB, gastrointestinal TB, visceral TB or mixed TB. RESULTS: eighteen patients were diagnosed with peritoneal TB, nine with lymph node TB, five with gastrointestinal TB, two with visceral TB and 36 with mixed TB. More than 65 % of the patients had tuberculosis of other sites except the abdomen. The median diagnosis time was 60 days. Ascites (58.6 %), abdominal distension (48.6 %), weight loss (44.3 %) and fever (42.9 %) were the most common symptoms. The overall microbiological and histological detection rates were 70.0 % and 38.6 %, respectively. The non-ascite samples yielded a higher microbiological confirmation rate (63.6 %) than the total samples (40.8 %). Diagnosis was confirmed histologically in 18 patients (69.2 %). Forty-five cases (64.3 %) were clinically diagnosed. Invasive procedures such as surgery (6/7), percutaneous biopsy (7/7) and endoscopy in lymph node TB (4/5) had high confirmation rates. CONCLUSIONS: the diagnosis of abdominal TB should be reached by a combination of clinical, laboratory, radiological, microbiological and pathological findings.

[Effects of myeloid specific deficiency of FBXW7 on lung metastasis of murine melanoma].

Objective: To investigate the effects of myeloid-specific deficiency of FBXW7 on lung metastasis of murine B16F10 melanoma and its mechanisms. Methods: Mice carrying the floxed allele of FBXW7 and lysozyme M-Cre were used for generation of mice with myeloid cell-specific deletion of FBXW7. Mouse genotypes were examined by genomic DNA PCR. B16F10 cells in PBS were injected into the tail vein of Lysm-FBXW7f/f and Lysm+FBXW7 f/f mice. After 14 d, the mice were sacrificed, and the lungs were removed and weighed. B16F10 tumor colonies in the lungs were counted. The myeloid cells were analyzed by flow cytometry. Results: Myeloid-specific deficiency of FBXW7 mice were generated successfully, as FBXW7 expressions in peritoneal macrophages and bone marrow-derived macrophages (BMDMs) of Lysm+FBXW7f/f mice were knockdown. Flow cytometry results showed the deletion of FBXW7 in myeloid lineages did not affect the development of myeloid immune cell subsets. Metastasis was reduced in Lysm+FBXW7 f/f mice compared with control mice. The number of tumor colonies was 165±42, 122±12 respectively. The proportion of metastasis-associated macrophages (MAM) in the lungs of Lysm+FBXW7 f/f mice was reduced [(23.15±7.59)% vs (13.13±2.26)%], while the proportion of resident macrophages was increased [(5.426±0.42)% vs (10.42±1.90)%]. The proportion of myeloid-derived suppressor cells in the lung showed no difference between Lysm-FBXW7f/f and Lysm+FBXW7 f/f mice. Conclusion: Myeloid-specific deficiency of FBXW7 can inhibit lung metastasis of B16F10 melanoma in mice, and the mechanism may be associated with regulation of MAM in the metastatic tumor lesions.

[Preparation, characterization and cytology study of Pluronic-PEI micelles].

Objective: To prepare and characterize Pluronic-PEI micelles as a drug/gene delivery system. Methods: We used the low-molecular-weight PEI as a cross-linking agent to prepare the Pluronic-PEI micelles. The particle size, zeta potential and critical micelle concentration (CMC) were measured by dynamic light scattering (DLS) and pyrene fluorescence probe. The cytotoxicity, transfection efficiency and the impact on the intracellular ATP and P-gp levels of Pluronic-PEI micelles were investigated at the cellular level. Results: Pluronic-PEI micelles were successfully prepared with a suitable particle size (120-180 nm), zeta potential (+6-+9 mv), and a good ability to carry the drug/gene. An in-vitro study showed that Pluronic-PEI had low cytotoxicity, and the P123-PEI600 possessed high gene transfection efficiency and could downregulate the intracellular ATP and P-gp levels. Conclusion: Pluronic-PEI is a good drug/gene delivery system, and P123-PEI600 is an ideal vector, which may be used in the combination therapy for reversing multidrug resistance.

[Bacterial outer membrane vesicles as nano carriers to study immunological activities].

Objective: To prepare a nano-carrier based on combining bacterial outer membrane vesicles (OMV) with three block polymer pluronic F127 (PEO100-PPO65-PEO100) (OMV-F127) and to investigate its immunological activity. Methods: Attenuated salmonella (sal) was cultivated. OMV were separated by centrifugal ultrafiltration or ultrasonication, and OMV-F127 was prepared by mechanical extrudation method. The protein contents and compositions were tested with BCA and SDS-PAGE; the morphology of OMV, F127 and OMV-F127 were observed with FM and TEM; the particle sizes and their zeta potential were determined with DLS. Mouse macrophage RAW246.7 cells were treated with OMV-F127 (50 µg/mL, 100 µg/mL) in vitro, and the concentrations of IL-12, TNF-α and IFN-γ in culture supernatant were measured with ELISA kits. Results: The contents of protein in separated OMV by centrifugal ultrafiltration and ultrasonication were 2.8 mg/mL and 2.7 mg/mL, respectively. SDS-PAGE showed the marker protein OmpF/C in OMV. Under the FM and TEM, ball-like structure of F127 and OMV-F127 was observed. Size analysis revealed that the diameters of OMV, F127 and OMV-F127 were 72±2 nm, 90±3 nm and 92±2 nm, respectively. ELISA tests revealed that OMV-F127 significantly stimulated the secretion of IL-12, TNF-α and IFN-γ in RAW246.7 cells. Conclusion: A nano-carrier based on bacterial outer membrane vesicles has been prepared, which can stimulate the secretion of cytokines and may have immunomodulatory effects.