The ascorbic acid in plasma was determined on the basis of reduction of ferric to ferrous ion and its formation of a colored complex with batho-phenanthroline. This method was highly correlated to Roe's dinitrophe-nylhydrazine method in the determination of plasma ascorbic acid of 16 normal adults and the correlation coefficient was 0.90. By animal experiment the new method may be used to discriminate different levels of plasma ascorbic acid. It is rather simple and water bath is not required. Only 0.25ml of plasma is needed for each determination. So this method is useful in assessing the ascorbic acid nutriture in tield survey.

Objective To investigate CT and MRI imaging of Warthin tumor of parotid gland.Methods CT and MRI character-istics of 5 1 patients confirmed as Warthin tumor by operation and pathology were analyzed retrospectively.Results Among 5 1 cases, 43 patients were males,and 8 patients were females.A total of 84 lesions were found in all cases,20 cases had at least 2 lesions.The margins of lesions were well-defined.68 lesions were round or elliptical.45 lesions located in the posterior and inferior quadrant of the parotid gland completely or premodinantly.The density and signal of most lesions were homogeneous.The parenchymal area of most lesions showed an early moderate-remarkable enhancement.Small blood vessels surrounded the lesions in 1 9 cases.Conclusion CT and MRI are important and valuable for the diagnosis of Warthin tumor.

Objective To discuss bilateral percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) using inside and outside intravertebral vacuum cleft (IVC) respectively with bone cement injection for the treatment of Kümmell disease.Methods From January 2008 to October 2015,16 cases of Kümmell disease patients were treated with bilateral PVP or PKP with inside and outside IVC perfusion of bone cement respectively.Of 16 cases,6 were male and 10 were female,aged from 63 to 94 years,with a disease duration from 2 to 15 months.The bone mineral density of every patient was measured by dual-energy X-rayabsorptiometry.The T value ranged from-4.3 to-2.6.Fractures located from T10 to L4,including 2 cases of multiple fractures.Postoperative X-ray was used to observe the vertebral bone cement leakage and anterior height changes of affected vertebrae.Visual analogue scale (VAS) and Oswestry disability index (ODI) were used to evaluate pain status and functional activity.Results All cases were followed up for 12-96 months.Cement leakage occurred in 4 patients without nerve complications.The anterior height of affected vertebrae before operation,2 d after operation and at the last follow-up was (50.3 ± 8.3)％,(67.1 ± 8.1)％ and (65.2 ± 6.4)％.The anterior height of affected vertebrae 2 d after operation and at the last follow-up were significantly improved compared with those before operation (P ＜ 0.05),but there were no significant differences between 2 d after operation and at the last follow-up (P ＞ 0.05).The scores of VAS before operation,2 d after operation and at the last followup was (8.63-± 1.23),(2.56 ± 3.48) and (1.38 ± 0.92) scores,and the scores of ODI was (82.1 ± 6.7)％,(28.5 ± 7.3)％ and (22.1 ± 8.2)％.The scores of VAS and ODI 2 d after operation and at the last follow-up were significantly decreased compared with those before operation (P ＜ 0.05),but there were no significant difference between 2 d after operation and at the last follow-up (P ＞ 0.05).There was no postoperative in situ or adjacent vertebral fracture.Conclusions Using internal and external IVC bone cement injection for treatment of Kümmell disease has a good clinical curative effect.It can effectively relieve back pain symptoms,reduce intraoperative and postoperative bone cement leakage and recurrent adjacent or in situ vertebral fracture.

Objective:To investigate the stress distribution in peri-implant bone with All-on-4 implant with various parameters by three-dimensional finite element method.Methods:An edentulous mandibular specimen was scanned by CT Mimcs.Geomagic,Uni-graphics,HyperMesh modeling software were used to establish All-on-4 implant finite element models with different inclination angles and corresponding cantilever lengths.1 50 N vertical static load was applied at the right end of the cantilever,peri-implant bone stress was analysed using Abaqus software.Results:When the distal implant inclined 0°with cantilever length of 1 9.5 mm,the peak stress in peri-implant cortical bone at the mesial and distal side was 25.526 MPa and 83.026 MPa respectively.When the distal implant in-clined 1 5°,30°and 45°with the cantilever length of 1 7.2 mm,1 3.3 mm and 9.8 mm,the stress in perio-implant cortical bone at distal side of the implant reduced by 1 2.4%,35.6% and 53.1 %,that at mesial side of the implant reduced by 1 3.6%,36.3% and 40.2%,respectively.Conclusion:From the perspective of the stress analysis,the design of All-on-4 distal implant with large incli-nation angle and short cantilever is superior to that with small inclination angle and long cantilever.

Objective To explore the neuroprotective effects ofβ-aescinate on brain edema in rats of traumatic brain injury (TBI). Methods A total of 78 male SD (Sprague Dawley) rats were randomly divided into three groups: sham-operation group (Sham), traumatic brain injury group (TBI) andβ-aescinate group, with 26 rats in each group. Rats of Sham group were anesthetized and surgically prepared only, but were not induced by cortical contusion. Electronic brain cortical damage impactor (eCCI) was used for establishing TBI model in TBI group and β-aescinate group after opening the bone window. TBI group was only established TBI model, but no intervention. After establishment of TBI model in β-aescinate group, β-aescinate (5 mg/kg body weight) was intraperitoneally injected, once every 24 hours. The modified neurological severity scores (mNSS) was used for evaluating changes of neurological function. After 48 hours, SD rats were sacrificed for hematoxylin and eosin (H&E) staining (n=6). Additionally, water content of the brain tissue was evaluated using the wet-to-dry weight ratio (n=10). Evans blue assay was performed to investigate the blood-brain barrier (BBB) permeability (n=4). The expression of aquaporin 4 (AQP4) was measured by Western blot assay (n=6). Results Compared with the Sham group, neurologic deficit, increased brain water content and the expression of AQP4 were found in TBI group (all P<0.05). Moreover, BBB permeability was destroyed. However, β-aescinate can improve the neurological function, reduce the brain water content and significantly decrease the expression of AQP4 in TBI rats. The BBB permeability was significantly improved in treatment group (all P<0.05). Conclusion These findings suggest that β-aescinate can reduce cerebral edema and improve neurological outcome in SD rats after TBI. This neuroprotection may be related with the down-regulation of AQP4 protein.

Objective To investigate the relationship between mismatch repair (MMR) protein expression and microsatellite instability (MSI) and tumor TNM staging in colorectal cancer. Methods The clinical data of 1351 patients who underwent radical resection of colorectal cancer at the Xijing Digestive Hospital of Air Force Military Medical University from January 2008 to December 2017 were retrospectively analyzed. The MMR and MSI status in patients with different gender, age and TNM staging were analyzed. Results Of the 1351 specimens, 291 (22％) didn't express MMR protein. Univariate analysis showed that there were significant differences in the deletion rates of MSH2, MSH6 and PMS2 between patients ≥60 years old and<60 years old (all P<0.05);there were significant differences in the deletion rates of MSH2 between stage T3 and the other stages (P<0.05); the deletion rates of MLH1, PMS2 among different N stages, and the deletion rates of MSH2 and MSH6 between stage N0 or N1 and the other N stages were significantly different (all P< 0.05); the deletion rates of PMS2 among different M stages were significantly different (P< 0.05). There were significant differences in PMS2 deletion rates among different TNM stages and MLH1, MSH2 and MSH6 deletion rates between stage Ⅱ or Ⅲ and the other stages (all P< 0.05). There was significant difference in MSI positive rates between patients ≥60 years old and<60 years old (P<0.05); there were significant differences in MSI positive rates between stage T3 or T4 and the other T stages, among different N or M stages, and between TNM stage Ⅱ, ⅢorⅣand the other TNM stages (all P<0.05). Conclusions The MMR protein expression and MSI in colorectal cancer patients are closely related to tumor TNM staging. Detection of MMR protein expression and MSI in colorectal cancer patients has certain reference value for judging TNM staging of colorectal cancer. To a certain extent, it can guide the diagnosis and treatment of patients with colorectal cancer and judge the prognosis.

Objective To evaluate the relationship betweenα2 adrenergic receptors and expression of Nav1. 8 in dorsal root ganglion (DRG) neurons, and to illuminate the mechanism of dexmedetomidine-induced reduction of acute visceral pain in rats. Methods Thirty-two clean-grade healthy adult male Spra-gue-Dawley rats, aged 6-8 weeks, weighing 180-220 g, were divided into 4 groups ( n=8 each) using a random number table method: control group ( group C ) , acute visceral pain group ( group VP ) , dexmedetomidine group (group D), and dexmedetomidine plus atipamezole group (group DA). In VP, D and DA groups, 10-3 mmol∕L capsaicin 1. 3 ml was injected into the rectum at a dose of 10-3 mmol∕L to establish the acute visceral pain model, while the equal volume of normal saline was given instead in group C. Atipamezole 1 mg∕kg was subcutaneously injected through the back of the neck at 20 min before establishing the model in group DA. Dexmedetomidine 10μg∕kg was injected through the tail vein at 15 min before establishing the model in D and DA groups, while the equal volume of normal saline was given instead at the correspording time points in C and VP groups. The visceral pain behavior score was recorded at 1 h after establishing the model. The animals were then sacrificed, and DRGs of the lumbar segment (L3-6) were removed for determination of the number of Nav1. 8 positive DRG neurons (by immunohisto-chemistry) and expression of Nav1. 8 mRNA (by quantitative real-time polymerase chain reaction). Results Compared with group C, the visceral behavior scores and the number of Nav 1. 8 positive DRG neurons were significantly increased, and the expression of Nav 1. 8 mRNA was up-regulated in VP, D and DA groups (P<0. 05). Compared with group VP, the visceral behavior score and the number of Nav1. 8 positive DRG neurons were significantly decreased, and the expression of Nav 1. 8 mRNA was down-regulated in D and DA groups (P<0. 05). Compared with group D, the visceral behavior scores and the number of Nav1. 8 positive DRG neurons were significantly increased, and the expression of Nav1. 8 mRNA was up-regulated in group DA ( P<0. 05) . Conclusion The mechanism by which dexmedetomidine reduces acute visceral pain is related to activatingα2 adrenergic receptors and to down-regulating the expression of Nav1. 8 in DRG neu-rons of rats.

Objective:To investigate the risk factors of lymph node metastasis for patients with colorectal cancer in T 3 and T 4, and to provide a reference for clinical diagnosis and treatment. Methods:The clinicopathological data of 1 112 patients with colorectal cancer in T 3 and T 4 who underwent radical resection of colorectal cancer in Xijing Digestive Disease Hospital from January 2008 to December 2017 were retrospectively analyzed. The correlation between lymph node metastasis status and the clinicopathological factors as well as tumor markers was analyzed. The related risk factors of lymph node metastasis were analyzed by using logistic multivariate regression analysis. Results:Univariate analysis showed that there was no statistically significant difference in the incidence of lymph node metastasis among colorectal cancer patients stratified by gender, age and tumor location (all P > 0.05). The different tumor diameter [<5 cm and ≥5 cm: 37.75% (211/559), 52.26% (289/553), χ2 = 23.666, P < 0.01], general type [infiltration, ulcer, parasol, bulge: 37.04% (20/54), 47.52% (432/909), 34.33% (23/67), 69.51% (57/82), χ2 = 13.787, P = 0.003], degree of differentiation [highly-differentiated, moderately-differentiated, poorly-differentiated: 34.11% (102/299), 49.00% (317/647), 48.80% (81/166), χ2 = 19.771, P < 0.01], mismatch repair deficiency (dMMR) [yes and no: 26.34% (64/243), 50.17% (436/869), χ2 = 43.996, P < 0.01], neurological invasion [yes and no: 48.17% (421/874), 33.20% (79/238), χ2 = 16.954, P < 0.01], vascular invasion [yes and no: 79.16% (338/427), 23.65% (162/685), χ2 = 327.493, P < 0.01] and preoperative carcino-embryonic antigen (CEA) [positive (≥5 mg/ml) and negative (<5 mg/ml): 52.87% (249/471), 39.16% (251/641), χ2 = 20.162, P < 0.01] and CA199 [positive (≥35 U/ml) and negative (<35 U/ml): 59.33% (124/209), 41.64% (376/903), χ2 = 21.465, P < 0.01] had statistically significant differences in the incidence of lymph node metastasis for above stratified patients. Logistic multivariate regression analysis showed that vascular invasion and preoperative CA199-positive were independent risk factors for lymph node metastasis in patients with colorectal cancer in T 3 and T 4 ( OR = 13.006, 95% CI 9.329-17.276, P < 0.01; OR = 2.194, 95% CI 1.513-3.181, P < 0.01), and dMMR-positive was a protective factor for lymph node metastasis ( OR = 0.279, 95% CI 0.190-0.411, P < 0.01). Conclusions:Vascular invasion is the main risk affecting factor for the lymph node metastasis of patients with colorectal cancer in T 3 and T 4. The detection of preoperative tumor marker CA199 can be used as an index to predict the lymph node metastasis of patients with colorectal cancer in T 3 and T 4. To a certain extent, it can provide a reference for the diagnosis and treatment of patients with colorectal cancer in T 3 and T 4.

Objective:To investigate the application prospect of 3D virtual reconstruction and printing technology based on thin-slice CT images in network cloud+dual-track teaching.Methods:A total of 120 medical students who were on probation in The Second Affiliated Hospital of Air Force Medical University from April 2021 to April 2022 were selected as subjects and were randomly divided into experimental group and control group, with 60 students in each group. The students in the experimental group received 3D virtual reconstruction and printing technology combined with network cloud+dual-track teaching, and those in the control group received network cloud+dual-track teaching alone. After 6 months of learning, the teaching effect was compared by closed-book examination, skill operation, speech defense, and questionnaire survey. SPSS 23.0 was used for the t-test and the chi-square test. Results:Compared with the control group in terms of department examination, the experimental group had significantly better scores of theoretical knowledge [(84.25±5.53) vs. (79.43±6.69), P<0.001] and operational skills [(87.68±5.72) vs. (82.97±5.32), P<0.001]. The experimental group had significantly higher scores than the control group in speech [(44.90±2.56) vs. (41.88±2.71), P<0.001] and defense [(45.83±2.62) vs. (43.85±2.56), P<0.001]. The questionnaire survey showed that compared with the control group, the experimental group had significantly higher scores of practical ability, active learning ability, expression ability, practice enthusiasm, and information acquisition ability ( P<0.001). Conclusion:The network cloud+dual-track teaching model assisted by 3D virtual reconstruction and printing technology can significantly improve the objective learning effect and subjective learning initiative of students and has a relatively high value of teaching application and promotion.

Background and Objectives: The search for a suitable alternative for urethral defect is a challenge in the field of urethral tissue engineering. Induced pluripotent stem cells (iPSCs) possess multipotential for differentiation. The in vitro derivation of urothelial cells from mouse-iPSCs (miPSCs) has thus far not been reported. The purpose of this study was to establish an efficient and robust differentiation protocol for the differentiation of miPSCs into urothelial cells. Methods: and Results: Our protocol made the visualization of differentiation processes of a 2-step approach possible. We firstly induced miPSCs into posterior definitive endoderm (DE) with glycogen synthase kinase-3β (GSK3β) inhibitor and Activin A. We investigated the optimal conditions for DE differentiation with GSK3β inhibitor treatment by varying the treatment time and concentration. Differentiation into urothelial cells, was directed with all-trans retinoic acid (ATRA) and recombinant mouse fibroblast growth factor-10 (FGF-10). Specific markers expressed at each stage of differentiation were validated by flow cytometry, quantitative real-time polymerase chain reaction (qRT-PCR) assay, immunofluorescence staining, and western blotting Assay. The miPSC-derived urothelial cells were successfully in expressed urothelial cell marker genes, proteins, and normal microscopic architecture. Conclusions We built a model of directed differentiation of miPSCs into urothelial cells, which may provide the evi-dence for a regenerative potential of miPSCs in preclinical animal studies.