A nomogram for predicting the overall survival in rectal cancer patients after total neoadjuvant therapy.

BACKGROUND: Total neoadjuvant therapy (TNT) has been recommended by the National Comprehensive Cancer Network for treating locally advanced rectal cancer (LARC), but extremely rare studies have focused on establishing nomograms to predict the prognosis in these patients after TNT. We aimed to develop a nomogram to predict overall survival (OS) in rectal cancer patients who underwent TNT. METHODS: In retrospective cohort study, we extract the data of the rectal cancer patients from the SEER database between 2010 and 2015, including demographic information and tumor characteristics. The cohort was divided into training set and validation set based on a ratio of 7:3. Univariate logistic regression analysis was utilized for the comparison of variables in training set. Candidate variables with P < 0.1 in training set was entered into the best subset selection, LASSO regression and Boruta feature selection. Finally, the selected variables significantly associated with the 3-year, 5-year, and 8-year OS were used to build a nomogram, followed by validation using receiver operating characteristic (ROC) curve, area under the curve (AUC), and calibration curve. RESULTS: A total of 3265 rectal cancer patients (training set: 2285; test set: 980) were included in the present study. A nomogram was developed to predict the 3-year, 5-year, and 8-year OS based on age, household income, total number of in situ/malignant tumors, CEA, T stage, N stage and perineural invasion. The nomogram showed good efficiency in predicting the 3-year, 5-year and 8-year OS with good AUC for the training set and test set, respectively. CONCLUSION: We established a nomogram for predicting the 3-year, 5-year, and 8-year OS of the rectal cancer patients, which showed good prediction efficiency for the OS after TNT.

[The combined application of oligoclonal bands in cerebrospinal fluid and IgG intrathecal synthesis indicators and biochemical markers in the diagnosis of multiple sclerosis].

Objective: To establish and verify a diagnostic model for distinguishing multiple sclerosis (MS) from other neurological diseases with similar symptoms by usingcerebrospinal fluid oligoclonal band (CSF-OCB)combined with IgG intrathecal synthesis indicators and biochemical markers. Methods: Multiple sclerosis (MS) patients admitted to the Neurology Department of Beijing Tiantan Hospital affiliated with Capital Medical University from January 2014 to December 2022 were selected as the case group, while patients with similar neurological symptoms were selected as the control group. Using the case-control study design, a retrospective analysis was conducted on the detection of age, gender, oligoclonal bands in cerebrospinal fluid, IgG intrathecal synthesis indicators and biochemical indicators for all study subjects. The differential diagnosis model was determined by the multiple logistic regression analysis, and the receiver operating characteristic (ROC) curve was used to analyze the diagnostic efficiency of the differential diagnosis model for neurological diseases with similar symptoms to MS and other conditions. Results: This study included 167 patients in the case group and 335 patients in the control group, of which 128 patients in the case group and 265 patients in the control group were used to construct the model, and 39 patients in the case group and 70 patients in the control group were used for model validation. The differential diagnostic model constructed by a multivariate logistic regression model was Y=0.871×CSF-OCB-0.051×CSFprotein-0.231×CSFchloride+1.183×gender-0.036×LDH+35.770. The model showed that the area under the curve, sensitivity and specificity were respectively 0.916, 87.3% and 87.6%. The Delong test results showed that the diagnostic efficacy of the model was significantly different from OCB, IgG intrathecal synthesis indicators, and OCB combined with IgG intrathecal synthesis indicators (P<0.05). The new model validation showed that the actual diagnostic consistency rate for the MS group was 84.6%, while the actual diagnostic consistency rate for the control group was 90.0%. Conclusion: This study combines OCB, IgG intrathecal synthesis indicators, and biochemical indicators to establish a diagnostic prediction model for neurological diseases with similar clinical symptoms in MS. This model may have good differential diagnostic value and can better assist clinical diagnosis in the early stages of disease progression in MS patients.

[Current status and prospects of clinical practice for arteriovenous graft in China].

The use of arteriovenous graft (AVG) fails to meet the clinical needs in China, although it is recommended by guidelines to be the alternative access for maintenance hemodialysis (MHD) patients. Patency and complication incidence of AVG reported by recent research is superior to traditional cognition, and thus AVG should be one of main types of access in our country. Personalized selection of proper patients and grafts may improve the outcomes of AVG. In the future, outcomes of AVG must be further improved by clinical research with accurate personalized selection, basic research of precise molecule target and innovation of graft materials.

[Efficacy and safety of early cannulation arteriovenous grafts for hemodialysis].

A total of 309 (138 males and 171 females) end-stage renal disease patients who underwent implantation of early cannulation arteriovenous grafts (Acuseal) for hemodialysis in Nanfang Hospital, Southern Medical University between December 2016 and May 2021 were retrospectively included. The age of patients was (61.5±10.3) years. There were 244 patients (119 males and 125 females) who received regular follow-up. During the follow-up period, 24 patients died. Perioperative complications included graft infection (4.5%, 11/244), hematoma (4.5%, 11/244) and steal syndrome (4.1%, 10/244). No seroma or anastomotic rupture occurred. The rates of the first postoperative puncture time within 24 h, 48 h and 72 h after implantation were 42.2%(103/244), 32.4% (79/244) and 16.4% (40/244), respectively. The Kaplan-Meier survival analysis showed that the primary patency rates at 6 months and 12 months were 66.5% and 48.4%, respectively, and the secondary patency rates at 6 months and 12 months were 96.7% and 91.8%, respectively. The current study indicates that the Acuseal graft is safe for vascular access in patients requiring hemodialysis, with satisfactory patency and acceptable complication rates at 1-year follow-up.

[Clinical application of inferior pancreaticoduodenal artery management in laparoscopic pancreaticoduodenectomy].

Objective: To investigate the clinical effect of proper management of inferior pancreaticoduodenal artery (IPDA) in laparoscopic pancreaticoduodenectomy (LPD). Methods: This is a retrospective case series study. The clinical and pathological data of 70 patients who received LPD due to pancreatic head tumors, periampullary tumors, or distal common bile duct tumors in the Pancreatic Center of the Second Clinical College of Guangzhou University of Chinese Medicine from January to December 2022 were retrospectively collected. There were 47 males(67.1%) and 23 females(32.9%),aged (59.9±12.8)years(range:13 to 87 years).The procedure of IPDA exposure was as follows:a middle approach was utilized to expose the right half of superior mesenteric artery(SMA) and its right branches between the SMA and superior mesenteric vein(SMV) in superior colonic region. In the subcolonic region,SMA trunk exposure via dissection along the jejunal artery from feet to head and identification the association between IPDA and jejunal artery were prior to IPDA root ligation and dissection. The safety and efficacy of intraoperative IPDA handling were assessed based on surgical videos. Follow-up was carried out in outpatient clinic or by telephone, and outpatient follow-up was conducted once every 1 to 3 months after surgery. Results: The percentage of total LPD was 98.6%(69/70),with all patients achieving R0 resection. Nine cases(12.9%) were involved in combined vascular resection and reconstruction,with 1 case (1.4%) requiring additional upper abdominal incision for vascular and gastrointestinal reconstruction,while the remaining eight cases (11.4%) were completed laparoscopically. The mean operative time was (432.7±115.4)minutes(range:282 to 727 minutes),and the mean blood loss was (140.0±125.7)ml(range:20 to 800 ml). Only two patients(2.9%) received fresh frozen plasma transfusion,with an average volume of 650 ml. Reliable ligation and safe handling of the IPDA were achieved in 91.4%(64/70) of cases, with 8.6%(6/70) suffering from IPDA injury-related bleeding. No one was converted to opened surgery. Pathologically,the mean tumor size was (3.3±1.6)cm (range:1 to 7 cm),and the mean number of harvested lymph nodes was 17.0±7.3(range:0 to 46). Lymph node metastasis was observed in 13 cases (18.6%). Five cases (13.2%) developed grade B pancreatic fistula,while no grade C pancreatic fistula occurred. Other complications included bile leakage in one case(1.4%),delayed gastric emptying in two cases(2.9%), lymphatic leakage in 2 cases(2.9%),intra-abdominal infection in 9 cases(12.9%),and fat liquefaction of surgical incision in 1 case(1.4%). Two cases(2.9%) experienced postoperative intra-abdominal bleeding,one due to mesangial bleeding of lesser curvature of the stomach and the other due to oozing from the hepatic arterial sheath. These bleeding events were not concerned with IPDA. The average length of postoperative hospital stay was (15.2±4.6)days(range:9 to 28 days). Conclusion: Proper intraoperative management of IPDA in LPD might reduce IPDA-related bleeding during and after surgery and improve the safety of LPD.

Automatic segmentation of high-risk clinical target volume and organs at risk in brachytherapy of cervical cancer with a convolutional neural network.

PURPOSE: This study aimed to design an autodelineation model based on convolutional neural networks for generating high-risk clinical target volumes and organs at risk in image-guided adaptive brachytherapy for cervical cancer. MATERIALS AND METHODS: A novel SERes-u-net was trained and tested using CT scans from 98 patients with locally advanced cervical cancer who underwent image-guided adaptive brachytherapy. The Dice similarity coefficient, 95th percentile Hausdorff distance, and clinical assessment were used for evaluation. RESULTS: The mean Dice similarity coefficients of our model were 80.8%, 91.9%, 85.2%, 60.4%, and 82.8% for the high-risk clinical target volumes, bladder, rectum, sigmoid, and bowel loops, respectively. The corresponding 95th percentile Hausdorff distances were 5.23mm, 4.75mm, 4.06mm, 30.0mm, and 20.5mm. The evaluation results revealed that 99.3% of the convolutional neural networks-generated high-risk clinical target volumes slices were acceptable for oncologist A and 100% for oncologist B. Most segmentations of the organs at risk were clinically acceptable, except for the 25% sigmoid, which required significant revision in the opinion of oncologist A. There was a significant difference in the clinical evaluation of convolutional neural networks-generated high-risk clinical target volumes between the two oncologists (P<0.001), whereas the score differences of the organs at risk were not significant between the two oncologists. In the consistency evaluation, a large discrepancy was observed between senior and junior clinicians. About 40% of SERes-u-net-generated contours were thought to be better by junior clinicians. CONCLUSION: The high-risk clinical target volumes and organs at risk of cervical cancer generated by the proposed convolutional neural networks model can be used clinically, potentially improving segmentation consistency and efficiency of contouring in image-guided adaptive brachytherapy workflow.

Ningxiang pig-derived Enterococcus hirae HNAU0516 ameliorates postweaning diarrhoea by promoting intestinal health and modulating the gut microbiota in piglets.

Early weaning-induced stress precipitates diarrhoea, significantly curtailing the growth performance of piglets. A pivotal contributor to this postweaning affliction is the emergence of gut bacterial dysbiosis. Enterococcus hirae, a promising probiotic, has indicated unclear effects and mechanisms on intestinal health. In this study, we investigated the effects and underlying mechanisms of oral supplementation with Ningxiang pig-derived Enterococcus hirae HNAU0516 orally supplementation on the gut bacterial community, immune response and gut barrier function in piglets. 21 d age Duroc × (Landrace × Yorkshire) piglets with a similar BW were randomly allocated to two groups. The Enterococcus hirae HNAU0516 administration group was inoculated orally with Ningxiang pig-derived Enterococcus hirae HNAU0516 throughout the trial period. Conversely, the control group received the same volume of physiological saline. Our findings revealed that Enterococcus hirae HNAU0516 supplementation effectively reduced diarrhoea rates of piglets (P = 0.010). Notably, this probiotic promoted intestinal development and enhanced intestinal barrier function. It also showed potential anti-inflammatory properties. Furthermore, Enterococcus hirae HNAU0516 supplementation significantly remodelled the colonic microbiota and increased the production of acetate (P = 0.007). In conclusion, our study highlights that Ningxiang pig-derived Enterococcus hirae HNAU0516 improves postweaning diarrhoea by promoting intestinal development, enhancing intestinal barrier function, decreasing intestinal permeability, modulating intestinal microbiota, and increasing short-chain fatty acids production.

Six1 Regulates Mouse Incisor Development by Promoting Dlx1/2/5 Expression.

Tooth development is a complex process orchestrated by intricate gene regulatory networks, involving both odontogenic epithelium and ectomesenchyme. Six1, a pivotal transcription factor (TF), is involved in the development of the lower incisor. However, its precise role during incisor development and the molecular mechanisms underpinning its regulatory functions remain poorly understood. This study employs Six1 deletion mouse models to elucidate the critical regulatory role of Six1 in governing dental mesenchyme development. By performing single-cell RNA sequencing, we constructed a comprehensive transcriptome atlas of tooth germ development from the bud to bell stage. Our analyses suggest that the dental follicle and the dental papilla (DP) are differentiated from dental ectomesenchyme (DEM) and identify the key TFs underlying these distinct states. Notably, we show that Dlx1, Dlx2, and Dlx5 (Dlx1/2/5) may function as the key TFs that promote the formation of DP. We further show that the deletion of Six1 perturbs dental mesenchyme development by impeding the transitions from DEM to DP states. Importantly, SIX1 directly binds to the promoters of Dlx1/2/5 to promote their co-expression, which subsequently leads to widespread epigenetic and transcriptional remodeling. In summary, our findings unveil Six1's indispensable role in incisor development, offering key insights into TF-driven regulatory networks that govern dental mesenchyme cell fate transitions during tooth development.

[The association between overweight/obesity and the risk of malignancy in Hürthle cell neoplasms of the thyroid].

Objective: To explore the association between obesity/overweight and the risk of malignancy in Hürthle cell neoplasms of the thyroid. Methods: The data of patients with complete data who were diagnosed with Hürthle cell neoplasms of the thyroid at the Third Hospital of Peking University from September 2016 to September 2023 were retrospectively collected. Based on postoperative pathological diagnosis, tumors were classified into thyroid Hürthle cell adenoma group and Hürthle cell carcinoma group. Multivariate logistic regression analysis was employed to explore the association between overweight/obesity and the risk of malignancy in Hürthle cell neoplasms of the thyroid. Results: A total of 102 patients (13 males and 89 females) were included, aged (48.7±13.1) years. There were 22 cases of thyroid Hürthle cell carcinoma and 80 cases of thyroid Hürthle cell adenoma. Univariate analysis showed that the rate of overweight/obesity in the Hürthle cell carcinoma group was higher than that in the adenoma group [73% (16/22) vs 46% (37/80), P=0.050]. Multivariate logistic regression analysis indicated that the overweight/obese patients had a higher risk of malignancy in Hürthle cell neoplasms of the thyroid compared with the non-overweight/obese patients (OR=3.170, 95%CI: 1.126-9.955, P=0.035). Sensitivity analysis excluding individuals with multiple tumors was consistent with the main study results (OR=2.878, 95%CI: 0.922-10.228, P=0.080). Conclusion: Overweight/obesity may be associated with a higher risk of malignancy in patients with Hürthle cell neoplasms of the thyroid.

[Mechanisms by which Mettl3 regulates pericyte-myofibroblast transdifferentiation through PI3K/AKT signaling pathway].

Objective: To investigate the role and underlying mechanisms of methyltransferase (Mettl) 3 in the process of angiotensin Ⅱ (Ang Ⅱ)-induced pericyte-to-myofibroblast transdifferentiation and renal fibrosis. Methods: C57BL/6J mice were used, in cell experiments, mouse renal pericytes were isolated and cultured using magnetic bead sorting. These pericytes were then induced to transdifferentiate into myofibroblasts with 1×106 mmol/L Ang Ⅱ, which was the Ang Ⅱ group, while pericytes cultured in normal conditions served as the control group. Successful transdifferentiation was verified by immunofluorescence staining, Western blotting, and real-time reverse transcription PCR (RT-qPCR) for α-smooth muscle actin (α-SMA). The levels of m6A modifications and related enzymes (Mettl3, Mettl14), Wilms tumor 1-associated protein (WTAP), fat mass and obesity protein (FTO), ALKBH5, YTHDF1, YTHDF2, YTHDC1, YTHDC2, YTHDC3 were assessed by Dot blot, RT-qPCR and Western blot. Mettl3 expression was inhibited in cells using lentivirus-mediated Mettl3-shRNA transfection, creating sh-Mettl3 and Ang Ⅱ+sh-Mettl3 groups, while lentivirus empty vector transfection served as the negative control (Ang Ⅱ+sh-NC group). The impact of Ang Ⅱ on pericyte transdifferentiation was observed, and the expression of downstream phosphatidylinositol 3-kinase (PI3K)/AKT signaling pathway proteins, including PI3K, AKT, phosphorylated AKT at serine 473 (p-AKT (S473)), and phosphorylated AKT at threonine 308 (p-AKT (T308)), were examined. PI3K gene transcription was inhibited by co-culturing cells with actinomycin D, and the half-life of PI3K mRNA was calculated by measuring residual PI3K mRNA expression over different co-culture time. The reversibility of Mettl3 inhibition on Ang Ⅱ-induced pericyte-to-myofibroblast transdifferentiation was assessed by adding the AKT activator SC79 to the Ang Ⅱ+sh-Mettl3 group. In animal experiments, mice were divided into these groups: sham group (administered 0.9% sterile saline), Ang Ⅱ group (infused with Ang Ⅱ solution), sh-Mettl3 group (injected with Mettl3 shRNA lentivirus solution), Ang Ⅱ+sh-Mettl3 group (infused with Ang Ⅱ solution and injected with Mettl3 shRNA lentivirus solution), and Ang Ⅱ+sh-Mettl3+SC79 group (administered Ang Ⅱ solution and Mettl3 shRNA lentivirus, with an additional injection of SC79). Each group consisted of six subject mice. Blood pressure was measured using the tail-cuff method before and after surgery, and serum creatinine, urea, and urinary albumin levels were determined 4 weeks post-surgery. Kidney tissues were collected at 28 days and stained using hematoxylin-eosin (HE) and Masson's trichrome to assess the extent of renal fibrosis. Results: Primary renal pericytes were successfully obtained by magnetic bead sorting, and intervened with 1×106 mmol/L Ang Ⅱ for 48 hours to induce pericyte-to-myofibroblast transdifferentiation. Dot blot results indicated higher m6A modification levels in the Ang Ⅱ group compared to the control group (P<0.05). RT-qPCR and Western blot results showed upregulation of Mettl3 mRNA and protein levels in the Ang Ⅱ group compared to the control group (both P<0.05). In the Ang Ⅱ+sh-Mettl3 group, Mettl3 protein expression was lower than that in the Ang Ⅱ group, with reduced expression levels of α-SMA, vimentin, desmin, fibroblast agonist protein (FAPa) and type Ⅰ collagen (all P<0.05). Compared to the control group, PI3K mRNA expression level was elevated in the Ang Ⅱ group, along with increased p-AKT (S473) and p-AKT (T308) expressions. In the Ang Ⅱ+sh-Mettl3 group, PI3K mRNA expression and p-AKT (S473) and p-AKT (T308) levels were decreased (all P<0.05). The half-life of PI3K mRNA was shorter in the Ang Ⅱ+sh-Mettl3 group than that in the Ang Ⅱ+sh-NC group (2.34 h vs. 3.42 h). The ameliorative effect of Mettl3 inhibition on Ang Ⅱ-induced pericyte-to-myofibroblast transdifferentiation was reversible by SC79. Animal experiments showed higher blood pressure, serum creatinine, urea, and 24-hour urinary protein levels, and a larger fibrosis area in the Ang Ⅱ group compared to the sham group (all P<0.05). The fibrosis area was smaller in the Ang Ⅱ+sh-Mettl3 group than that in the Ang Ⅱ group (P<0.05), but increased again upon addition of SC79. Conclusion: Mettl3-mediated RNA m6A epigenetic regulation is involved in Ang Ⅱ-induced pericyte-to-myofibroblast transdifferentiation and renal fibrosis, potentially by affecting PI3K stability and regulating the PI3K/AKT signaling pathway.

Biological Mediators and Partial Regulatory Mechanisms on Neuropathic Pain Associated With Chemotherapeutic Agents.

One of the most common issues caused by antineoplastic agents is chemotherapy-induced peripheral neuropathy (CIPN). In patients, CIPN is a sensory neuropathy accompanied by various motor and autonomic changes. With a high prevalence of cancer patients, CIPN is becoming a major problem for both cancer patients and for their health care providers. Nonetheless, there are lacking effective interventions preventing CIPN and treating the CIPN symptoms. A number of studies have demonstrated the cellular and molecular signaling pathways leading to CIPN using experimental models and the beneficial effects of some interventions on the CIPN symptoms related to those potential mechanisms. This review will summarize results obtained from recent human and animal studies, which include the abnormalities in mechanical and temperature sensory responses following chemotherapy such as representative bortezomib, oxaliplatin and paclitaxel. The underlying mechanisms of CIPN at cellular and molecular levels will be also discussed for additional in-depth studies needed to be better explored. Overall, this paper reviews the basic picture of CIPN and the signaling mechanisms of the most common antineoplastic agents in the peripheral and central nerve systems. A better understanding of the risk factors and fundamental mechanisms of CIPN is needed to develop effective preventive and therapeutic strategies.

[Educational attainment increases the risk of developing allergic rhinitis and (or) eczema: a Mendelian randomization study based on genome-wide association studies in European patients].

Objective: To determine the causal relationship between educational attainment and the risk of allergic rhinitis and (or) eczema using Mendelian randomization (MR) analyses. Methods: This study was a secondary data analysis based on the summary data of genome-wide association studies (GWAS), which involved 293 723 participants (educational attainment) from the Social Science Genetics Association Consortium and 462 013 participants [allergic rhinitis and (or) eczema] from the UK Biobank. Genetic variants that were closely related to educational attainment were identified as instrumental variables. Two-sample MR analyses, including inverse-variance weighted (IVW), MR-Egger regression, weighted median method and weighted model-based estimation, were performed to investigate the causal relationship between educational attainment and the risk of allergic rhinitis and (or) eczema, in which the odds ratio (OR) values were used as indicators. Results: A total of 70 single-nucleotide polymorphisms (SNPs) were chosen as instrumental variables. The MR-Egger regression results suggested that the genetic pleiotropy was unlikely to bias our results (P=0.107). In the univariable MR analyses, IVW regression showed that the risk of allergic rhinitis and (or) eczema was OR=1.044 (95%CI: 1.020-1.069, P<0.001) and OR=1.170 (95%CI: 1.074-1.256, P<0.001), respectively, for the increase in the duration of education by one year or one standard deviation (SD) (3.71 years). In the reverse MR analysis, IVW regression showed little evidence that allergic rhinitis and (or) eczema affected educational attainment (OR=1.020, 95%CI: 0.927-1.023, P=0.683). The results of the weighted median method and weighted mode-based estimation were consistent with the results of IVW. Conclusion: This study suggests that there is a positive causal relationship between educational attainment and the risk of allergic rhinitis and (or) eczema, which means that educational attainment can increase the occurrence of allergic rhinitis and (or) eczema.

[Molecular characteristics and drug susceptibility analysis of Streptococcus agalactiae from respiratory specimen sources].

To study the carriage status of drug susceptibility, clonal complex groups, serotypes, surface proteins and virulence genes of Streptococcus agalactiae from respiratory specimen sources. A total of 35 strains of S.agalactiae meeting the criteria were collected from 3 hospitals in 2 locations, Tangshan and Jinan. The age span of the patients was 3 days-92 years, and the percentage of elderly patients≥60 years was 71.5%.The susceptibility to 9 antimicrobial drugs was measured and analyzed using the micro broth dilution method. The strains were 100.0% sensitive to penicillin, linezolid, vancomycin, and ceftriaxone; However, it exhibits high resistance rates to erythromycin, clindamycin and levofloxacin, at 97.1%, 85.7% and 82.9% respectively; and the resistance rates to tetracycline and chloramphenicol were 34.3% and 14.2%, respectively. Genome sequence determination and analysis showed that 16 resistance genes were detected in 35 strains, among which: macrolide and lincosamide resistance genes were mainly ermB, with a carrying rate of 74.2%; tetracycline resistance genes were mainly tetM, with a carrying rate of 25.7%; in addition, the mutation rates of the quinolone resistance determinants gyrA and parC were 88.5% and 85.7%, respectively. 35 strains belonged to 6 ST types and 4 clonal groups, with CC10/ST10 as the main one, accounting for 62.8%; they contained 4 serotypes of Ⅰb, Ⅱ, Ⅲ, and Ⅴ, as well as 1 untyped strain, with serotype Ⅰb as the main one, accounting for 65.7%. The strains carried three pilus types, PI1+PI2a, PI2a and PI2b types, respectively, and detected five surface proteins, alpha, alp1, rib, srr, and rdf_0594, and seven virulence factors, cba, cfb, cylE, fbsA, hylB, lmb, and pavA. Overall, S.agalactiae isolated from respiratory tract specimens is predominantly sourced from elderly patients, with CC10 strains being most prevalent. These strains harbor multiple drug-resistant and virulence genes, demonstrating elevated resistance rates to macrolides, lincosamides, and quinolones. This emphasizes the necessity for vigilant attention to the health threat posed by S. agalactiae from respiratory tract speciments of elderly patients.

[Study of the methotrexate loaded extracellular vesicles in the treatment of experimental periodontitis in mice].

Objective: To investigate the therapeutic effect of methotrexate loaded vesicles on experimental periodontitis in mice. Methods: Extracellular vesicles (EVs) were isolated from human umbilical cord mesenchymal stem cells (hUC-MSC). Methotrexate loaded vesicles (MTX-EVs) were constructed, whose morphology and size were analyzed by using scanning electron microscopy and particle size analyzer. Western blotting was used to identify their surface specific proteins. C57BL/6J male mice of 4-5 weeks (provided by Experimental Animal Center of The Fourth Military Medical University) were selected, among which 8 were randomly selected by blind grasp method without treatment and fed normally as normal group, and others were induced to periodontitis models by local injection of lipopolysaccharide (LPS) into the periodontium. The LPS was injected once every day with a concentration of 2 g/L and a volume of 5 µl, lasting for two weeks. The mice with successfully induced periodontitis were randomly divided into 4 groups by blind grasping method, with 8 mice in each group. The LPS group was with no treatment, and the other three groups were treated with periodontal local injection of MTX, EVs or MTX-EVs, respectively. Two weeks later, enzyme-linked immunosorbent assay (ELISA) was used to detect the expressions of inflammatory cytokine interleukin (IL)-1ß, IL-6 and tumor necrosis factor-α (TNF-α) in gingival tissue. The amount of alveolar bone resorption of four groups was detected by using micro-CT scanning and HE staining. The expression proportion of the inflammatory factor in gingival tissue was analyzed by using flow cytometry. Results: The scanning electron microscopy results showed that EVs and MTX-EVs were circular or elliptical in shape. Dynamic light scattering (DLS) particle size analysis showed that the particle size of EVs was around 200 nm, while that of MTX-EVs was around 300 nm. The ELISA results showed IL-1ß levels in the normal group, LPS group, LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were (28.86±2.76), (51.50±2.04), (35.26±2.40), (45.49±2.04) and (35.77±3.49) ng/L. That is, the IL-1ß concentrations in the LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were significantly lower than that in the LPS group (P<0.05); the mass concentration of IL-1ß in the LPS +MTX-EVs group was significantly lower than that in the LPS+EVs group (P<0.05). The concentrations of IL-6 in the normal group, LPS group, LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were (125.44±4.12), (221.64±10.59), (178.16±16.90), (181.09±18.22) and (170.15±9.04) ng/L, among which the concentration of IL-6 in the last three groups were significantly lower than that in the LPS group (P<0.05). The mass concentration of IL-6 in the LPS+MTX-EVs group was significantly lower than those in the LPS+MTX group and LPS+EVs group (P<0.05). The concentrations of TNF-α in the normal group, LPS group, LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were (320.27±38.68), (479.62±40.94), (342.18±25.89), (415.88±12.01) and (325.75±30.83) ng/L, among which the concentrations of last three groups were significantly lower than the LPS group (P<0.05); the mass concentration of TNF-α in the LPS+MTX-EVs group was significantly lower than those in the LPS+EVs group and LPS+MTX group (P<0.05). The micro-CT results showed that the distance of cement-enamel junction-alveolar bone crest (CEJ-ABC) of the first molar and root (M1R1) in the normal group, LPS group, LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group of mice were (0.11±0.03), (0.28±0.02), (0.23±0.03), (0.20±0.04), and (0.18±0.03) mm, respectively. Compared with the LPS group, the CEJ-ABC of the M1R1 in the LPS+MTX group, LPS+EVs group and LPS+MTX-EVs group were inhibited to varied degrees with statistically significant differences (P<0.05). Among them, LPS+MTX-EVs group had the best bone resorption inhibitioin effect compared to LPS+MTX group and LPS+EVs group, and the differences were statistically significant (P<0.05). The flow cytometry results indicated that the proportion of interferon-γ (IFN-γ) positive cells was (11.77±1.02)% in the LPS group, (6.87±0.65)% in the LPS+EVs group, and (4.15±0.92)% in the LPS+MTX-EVs group, respectively. The proportions of IFN-γ positive cells in the LPS+EVs group and LPS+MTX-EVs group were significantly lower than that in the LPS group (P<0.05), while the ratio of IFN-γ positive cells in the LPS+MTX-EVs group was found significantly lower than that in the LPS+EVs group (P<0.05). Conclusions: MTX-EVs can effectively alleviate the periodontal local inflammatory environment and reduce bone resorption of alveolar bone in periodontitis model mice.