Objective To investigate the clinical characteristics and related risk factors of infarction secondary to severe traumatic brain injury.Methods 480 traumatic brain injury patients were chosen.Depending on the occurrence of cerebral infarction,patients were divided into TCI groups and non-TCI group,clinical symptoms and signs of TCI group were observed,and its related risk factors was analyzed.Results In 480 cases patients,there were 30 cases of patients with traumatic brain injury secondary to cerebral infarction,the rate was 6.25%.Clinical manifestations included unilateral limb motor and sensory dysfunction,visual dysfunction,language dysfunction,dizziness,headache.10 cases Prognosis were good,6 cases were mild disability,3 cases were severe disability,1 case was plant survival,10 patients died.Univariate analysis showed that the rates of aged ≥50 years,GCS score ＜ 8 points,hernia,hypotension,subarachnoid hemorrhage,large doses of non-dehydrating agent in the TCI group were higher than those of non-TCI group,the differences were statistically significant (x2 =12.311 3,14.725 4,19.867 8,5.296 9,9.242 6,11.713 6,all P ＜ 0.05).Logistic multivariate analysis showed that age ≥50 years,GCS score ＜ 8 points,hernia,cerebral hypotension were important risk factors.Conclusion Brain injury patients with cerebral infarction secondary to clinical manifestations have some characteristics.Age ≥50 years,GCS score ＜ 8 points,hernia,hypotension are important risk factors.

Objective To explore the spiral the normal representations of permanent teeth and alveolar bone of multi-slice spiral(MSCT). Methods 30 adults with normal teeth were studied by multislice spiral CT scanner,window width and window level was 3000~5000 HU and 1200~1500 HU respectively.MSCT findings were analysed using multiplanar reformation,dental panorama and 3D reconstruction were done in all cases.Results The tooth were showed as multilaryer structures with different density at MSCT because of the mineral content of different part of tooth,from high to low density was enamel,circumpulpal dentin,outside dentin,cementum and pulp.The periodontal membrane was low density located beween the cementum and lamina dura and the thickness was homogeneous.The bone cortex of alveolar bone was successive,the bone trabecula appeared as wirelike or reticulate.Conclusion The structures of permanent teeth and alveolar bone can be displayed clearly by MSCT.Multiplanar reformation,dental panorama and 3D reconstruction are helpful to display the structures of teeth and alveolar bone as well as the relationship around structures.

Objective To evaluate the radiation dose in both low radiation dose and to conventional radiation dose mode in multislice spiral CT scan for children with embedded teeth,and explore the lowest conditions of exposure in multislice spiral CT scan for children embedded teeth.Methods Eighty cases of children with embedded teeth examined by 16 slices spiral CT were divided into 5 ,25,125 and 250 mAs scanning groups.The scanned pictures of four groups were evaluated by two chief physicians and three associate chief physicians in the radiological department with double blind method.The CTDI_w and DLP in different radiation dose mode were recorded and analyzed with statistics.Results All the four groups scanned pictures in different radiation dose mode could accurately show the structure and the adjacency relation of embedded teeth.Even though the resolution of scanned pictures in S mAs group were inferior to the other three groups on bone trabecula,gingiva and their surrounding soft tissue,it still could meet the requirements of examination.The average DLP in 5 mAs group was only 2% of value in 250 mAs group.Conclusions MSCT in 5 mAs group can not only meet the requirements of examination,but also reduce the radiation dose to patients to the greatest extent.

A new approach based on online coupled liquid chromatography-gas chromatography-mass spectrometry ( LC-GC / MS ) was developed for the rapid determination of 4-( methylnitrosamino )-1-( 3-pyridyl)-1-butanone (NNK) in mainstream cigarette smoke, in which a switching valve was employed to online switching between two-dimensional chromatography. The online LC-GC / MS system used in this study was built by using online gel permeation chromatography-gas chromatography-mass spectrometry except that the micro gel column was replaced by micro alkaline alumina column which was prepared by ourselves before. The NNK in mainstream cigarette smoke was collected by a Cambridge filter pad, then the pad was extracted with dichloromethane, and the extract was quantitatively analyzed by online LC-GC / MS with D4-NNK as an internal standard. Online LC-GC / MS allowed online pretreatment purification, and the sample was subjected to online LC-GC / MS without any prior purification, which reduced human error in analysis process. The injection volume of the present online LC-GC / MS could reach 40 μL, which was 20 times of that of the conventional GC / MS (2. 0 μL of injection volume), and thus significantly improved the sensitivity. Under the optimum conditions, good linearity ( r = 0. 9998) was obtained over the range of 1. 2 - 120 ng / mL. The recoveries at three spiked levels ranged from 93. 9% to 96. 0% , and the limits of detection for qualitative and quantitative detection were 0. 25 ng / mL and 0. 9 ng / mL, respectively. All the results obtained by the present method are comparable to those of standard method recommend by China National Tobacco Company.

Objective To evaluate the effect of pretransplant iron overload on the clinical efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with severe aplastic anemia (SAA). Methods Clinical data of 80 SAA recipients who underwent allo-HSCT for the first time were retrospectively analyzed. According to the incidence of iron overload, all recipients were divided into the iron overload group (n=20) and non-iron overload group (n=60). The engraftment rate, incidence of postoperative complications and clinical prognosis of the recipients afterallo-HSCT were statistically compared between two groups. The influencing factors of 2-year overall survival (OS) and 180 d transplantation related mortality (TRM) were analyzed by Cox proportional hazards regression model. Results The engraftment rate of neutrophils in the non-iron overload group was 98% (59/60), significantly higher than 75% (15/20) in the iron overload group (P < 0.05). The engraftment rate of platelet in the non-iron overload group was 90% (54/60), significantly higher than 65% (13/20) in the iron overload group (P < 0.05). The incidence rate of bloodstream infection in the non-iron overload group was 23% (14/60), remarkably lower than 40% (8/20) in the iron overload group (P < 0.05). The 180 d TRM of the recipients in the non-iron overload group was 17%, significantly lower than 45% in the iron overload group (P < 0.05). The 1- and 2-year OS of the recipients in the non-iron overload group were 82% and 80%, significantly higher than 50% and 44% in the iron overload group (both P < 0.05). Iron overload or not was an independent risk factor of the OS and TRM of the recipients (both P < 0.05). Conclusions Iron overload can affect the OS and TRM of SAA patients after allo-HSCT.

Single-cell RNA-seq (scRNA-seq) can describe the changes of gene expression in a single tumor cell. And it can reveal the status and function of tumor cells, and capture the extensive transcriptome heterogeneity in the cell population. The application of scRNA-seq can monitor the specific highly expressed genes in esophageal squamous cell carcinoma (ESCC) , and it can also monitor genes related to radio chemotherapy resistance in tumor cells, which is helpful to provide more accurate auxiliary diagnosis for ESCC. Besides, scRNA-seq can evaluate the recurrence risk and survival time of patients. An in-depth study of the relationship between tumor cells and tumor microenvironment in ESCC will provide a theoretical basis for developing a new immunotherapy scheme for ESCC.

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.

Objective To analyze the epidemiologic and clinical features of post-engraftment blood stream infection (pePSI) after unrelated cord blood transplant (UCBT) in our hospital,and provide the basis for empiric antibacterial treatment.Methods 484 patients with hematological malignancies who received single-unit high intensity myeloablative UCBT in our hospital between April 2011 and November 2017 were enrolled.The incidence,etiology of BSI and associated mortality,drug resistance rate in the post-engraftment phase were investigated.Results Totally 25 episodes of BSI among 22 patients in the post-engraftment phase were documented,and the incidence of peBSI was 5 ％.Gram-negative organisms predominated over Gram positive,with Escherichia coli being the most frequent Gram-negative organism isolated (31.5％).Among Gram positive organisms,methicillin resistant Staphylococcus (MRS) was the most frequent species isolated (66％).Nearly 33％ of Escherichia coli isolates and 60％ Klebsiella pneumonia isolates were carbapenem-resistant.All Grampositive bacteria were sensitive to vaneomyein and linezolid.Among the 22 patients,14 patients were cured and survived (63％) eventually.Conclusion The most frequent causative agents of the peBSI after UCBT were Escherichia coli,Klebsiella pneumonia and MRS,etc.Combined antibacterial treatment including a carbapenem or beta lactamase inhibitor can be used for patients suffering fever in the post-engraftment phase as empiric antibacterial therapy.Vaneomyein and linezolid can be used as the first-line therapy for Gram-positive bacteria.

Objective:To determine influential factors for delayed breastfeeding initiation.Methods:Using questionnaires to collect the data of 950 pregnant women and infants' feeding practices in Changsha,Hunan,logistic regression and decision tree model were used to determine influential factors for delayed breastfeeding initiation.Results:Mothers with timely breastfeeding initiation were 594 (62.5％),and those with delayed breastfeeding initiation accounted for 356 (37.5％).Mothers with timely breastfeeding initiation were more likely to use exclusive breastfeeding than those with delayed breastfeeding initiation (P＜0.05).Four risk factors were found by logistic regression model and decision tree model,including cesarean delivery,using feeding-bottle before breastfeeding initiation,falling ill,and vomiting during pregnancy.Receiver operating characteristic curve showed no significant difference in the predictive effect of the 2 models (Z=0.142,P=0.889).Conclusion:Cesarean delivery,using feeding-bottle before initiation of breastfeeding,and poor physical condition during pregnancy exert negatively effects on breastfeeding initiation.Health workers should help mother to timely initiate breastfeeding and enhance their confidence in exclusive breastfeeding.

Objective:To explore the feasibility and efficacy of umbilical cord blood transplantation (UCBT) in the treatment of paroxysmal nocturnal hemoglobinuria (PNH).Methods:From May 2014 to December 2019, clinical data were retrospectively reviewed for 7 PNH patients undergoing UCBT. The grades were severe ( n=6) and extremely severe ( n=1). The causes were primary PNH ( n=4) and PNH-aplastic anemia (AA) syndrome ( n=3). There were 5 males and 2 females with a median age of 29 (20-47) years, a median weight of 60(50-71) kg and a median time from diagnosis to transplantation of 62.5(7.7-171) months. All of them were accompanied by transfusion dependence. Myeloablative ( n=6) and reduced-intensity ( n=1) pretreatment was offered. The regimen of preventing GVHD was cyclosporine A plus short-term mycophenolate mofetil without ATG. The median number of input nucleated cells was 2.4(1.71-4.28)×10 7/kg and the median number of CD34+ cells 1.58(0.88-3.02)×10 5/kg. Results:Neutrophil and erythroid engraftment was obtained with a median neutrophil engraftment time of 17(15-21) days and a median erythroid engraftment time of 27. Engraftment time of 37(25-101) days for platelets >20×10 9/L and 62(27-157) days for platelets >50×10 9/L. The incidence of 100-day acute GVHD was 28.6%(95%CI 0-55.3%). The severity of GVHD was grade Ⅱ° acute ( n=2) and mild ( n=1). The median follow-up period was 13.5(3-71.4) months. Six patients survived while another with PNH-AA syndrome with iron overload died of gastrointestinal hemorrhage. The 2-year overall survival rate was 83.3%(95%CI 27.3-97.5%). Conclusions:With excellent engraftment and survival in the treatment of PNH, UCBT is indicated for patients without HLA full-match donor. PNH-AA syndrome with iron overload may be one of the important prognostic factors.