Additive manufacturing (AM) is a collection of technologies based on the layer-by-layer manufacturing. Characterized by its direct manufacturing and rapidity, it has been regarded by the Economist Journal as one of the key techniques which will trigger the third industry reformation. The present article, beginning with a brief introduction of the history of AM and the process of its major technologies, focuses on the advantages and disadvantages and medical applications of the technique.
Medicine ; Printing, Three-Dimensional

Objective:To investigate the distribution of precancerous conditions and lesions of high-risk population in the high-in-cidence area of esophageal cancer in Ci County, Hebei Province. Methods:Esophageal cancer was detected early in 40 to 69 year old patients in Ci Xian through endoscopic screening data and endoscopic screening using iodine staining and indicative biopsy. The pa-tients were classified according to gender, age group, statistical esophageal precancerous condition, and lesion detection rate. Results:The analysis included 11 423 cases by screening queue, and the esophageal biopsy rate was 66.90%. The detection rates of squamous epithelium with mild, moderate, and severe dysplasia were 11.84%, 2.66%, and 1.04%, respectively. DCIS detection rate was 0.40%in patients with squamous cell carcinoma. The detection rate of the patients had been infiltrated by the squamous cell carcinoma was 0.04%.The rate of the squamous cell carcinoma within the mucosa was 0.37%.The rate of the infiltration squamous cell carcinoma was 0.17%. The detection rate of the hyperplasia above average severe dysplasia and cancer was 2.01%. Conclusion: High incidence of esophageal precancerous lesions was found in the Ci County aged 40 to 69. A large number of asymptomatic patients with cancer were detected. Age and sex are closely related to detection rate.

Objective To evaluate the correlation of intrahepatic HBV DNA load with the HBV load in serum and peripheral blood mononuclear cells(PBMC)and the stage of fibrosis,grade of inflammation,level of serum ALT and AST.Methods Liver specimens were taken from 50 patients by percutaneous needle biopsy and divided into two parts:one was processed for histological examination,and the other was used for molecular biology analyses.HBV DNA load was measured with fluorescent quantitative polymerase chain reaction(FQ-PCR).The data of serum level of ALT and AST were collected.Results A high correlation between intrahepatic HBV-DNA load and serum virus load was found(r=0.77977,P

Objective To investigate the etiology, epidemiologic features and drug resistance tendency of acute infectious diarrhea among children in Beijing area. Methods Enteric pathogenic bacteria were isolated, cultured and identified for serotype from the stool specimens of children with the initial clinical diagnosis of acute bacterial diarrhea in the intestinal clinic from January to October in 2009 ,and the antibiotic susceptibility of bacteria was tested by disk diffusion method. The cluster A rotavirus antigen was also detected by the qualitative technique of immunochromatographic double-antibody sandwich assay. Results Of the 256 stool specimens, 87 strains of 4 species of pathogenic bacteria were detected with the detectable rate of 34. 0% ,of which 2 strains were detected in one stool sample ,including 40 strains of salmonella (46. 0%) ,23 strains of shigella (26. 4%) ,2 strains of diarrheogenic escherichia coli (2. 3%) and 22 strains of staphylococcus aureus (25.3%). The positively detected patients consisted of 54 males and 32 females with the ratio of 1.69∶1 ,of whom 55 cases (64. 0%) were under 2 years of age. Of the 13 strains of shigella, 13 were sonnei shigella (56. 5%). And of the 22 strains of staphylococcus aureus,20 were detected among the infants under 1 year of age. The rates of crug resistance to certain antibiotics were lower in salmonella than in shigella (ampicillin :65. 0% vs. 95.7% ;compound sulfamethoxazole:20. 0% vs. 78. 3% ;ciprofloxacin:7.5% vs.8. 7% ;ceftriaxone: 15.0% vs. 73.9%). Of the 256 stool specimens ,47 were found positive for cluster A rotavirus,of whom 13 were also positive in stool bacteria culture. Conclusion Salmonella is the major pathogen among children with bacterial diarrhea in Beijing in 2009, and sonnei shigella is the main epidemic strains of shigella diarrhea. lnfants under 2 years of age are the susceptible population of the above two species of bacteria, while staphylococcus aureus mainly infect the infants under 1 years of age. Multi-resistance in shigella is still serious. The incidence of mixed infections of bacteria and rotavirus increases in children with infectious diarrhea.

Objective: Epithelial dysplasia of the esophagus and gastric cardia is precancerous lesion, including mild, moderate and severe levels. In 2000 year, WHO recommended to replace dysplasia with intraepithelial neoplasia. Mild and moderate dysplasia were classified as low-grade intraepithelial neoplasia (LIN). Cardia adenocarcinoma was suggested to be called esophageal-gastric junction adenocarcinoma. The risk of cancer development and the rule of time evolution were detected in esophagus and esophageal-gastdc junction LIN in high incidence area of esophageal cancer in Northern China, in an effort to provide scientific data for the prevention of esophageal cancer. Methods: Between October 2001 and October 2002, two townships of Cixian were chosen to carry out endoscopic iodine staining screening cohort study. The total population aged 0-85 was 22,016, of which 6,596 aged 40-69 (3257 males and 3339 females). Except for thoese with contraindications and those who refused to join the study, 3,506 cases were finally recruited in the study, and the screening rate was 53.2%. According to WHO criteria of the pathological diagnosis, the esophageal squamous epithelium with mild and moderate dysplasia and esophageal-gastric junction with mild dysplasia were classified into LIN groups (including 616 cases). The control group contained a total of 2,478 cases without precancerous lesions and free of cancer in endoscopic screening. Results: From June to September in 2008, the cohort was followed up and 174 cases were lost, with a follow-up rate of 95.0%. Follow-up was 3,970.7 person- years in the LIN group and 16,120.0 person-years in the control group.Carcinomous conversion rates were 251.7 and 68.2/per 100,000 person- years respectively in the LIN group and the control group. The median time in the two groups was 38 and 47 months, respectively. Compared with that of the normal population, the relative risk (RR) of LIN was 3.69 (95% CI=1.57-8.69, P=0.001). Conclusion: Population with LIN are at high-risk for esophageal cancer and endoscopic examination every year is absolutely necessary.

Objective To investigate the expression level of immunoglobulin G (IgG)4 cells in patients previously diagnosed as unexplained liver injuries,and to analyze whether these patients could be diagnosed as immunoglobulin G4-related disease (IgG4-RD).The clinical characteristics of patients with IgG4 positive cells infiltration in liver tissues who did not met IgG4-RD diagnosis criteria were also analyzed.Methods From August 2010 to July 2016,33 patients with unexplained liver injuries even after liver biopsy were enrolled.Immunostaining of IgG and IgG4 in liver tissue slices was performed.Whether the patients met the IgG4-RD diagnosis criteria was analyzed.Also,the relation between IgG4 positive cell infiltration in liver tissues and serum parameters (alanine aminotransferase (ALT),aspartate transaminase (AST),alkaline phosphatase (ALP),γ-glutamyl transpeptadase (GGT),IgG),the classification of liver inflammation and stage of liver fibrosis were analyzed.Chi-square,Fisher exact probability method,t test and Wilcoxon rank and inspection were used for statistical analysis.Results Among 33 patients with unexplained liver injuries,average age of onset of the disease was (50.48 ± 14.52) years old.Ten patients (30.3 ％) presented with different degree of IgG4 positive cells infiltration in liver.In one patient,the IgG4 positive cell number in liver tissue was over 10/high-powered field (HPF),IgG4+ / IgG+ ratio was over 40％,the serum IgG4 increased and low density nodules in the left hepatic lobe level,which met the diagnostic criteria of IgG4-RD.Serum parameters of liver function of this patient were as follows:ALT 948 U/L,AST 658 U/L,ALP 176 U/L,GGT 197 U/L,TBil 21.5 μmol/L,DBil 10.0 μmol/L.According to whether there were IgG4 positive cells infiltration in liver tissues,33 patients were divided into IgG4 positive cells infiltration group (IgG4 positive group,10 cases) and no IgG4 positive cells infiltration group (IgG4 negative group,23 cases).The medium levels of ALT,AST,ALP and GGT in the IgG4 positive group and the IgG4 negative group were 26.0 U/L vs 31.0 U/L,28.5 U/L vs 32.0 U/L,114.0 U/L vs 77.0 U/L,65.0 U/L vs 36.0 U/L,respectively and there were no statistically significant differences (Z=-0.098,-0.216,-0.862,-0.705;all P＞0.05).The serum IgG level of the IgG4 positive group was higher than that of the IgG4 negative group (17.15 g/L vs 13.65 g/L),and the difference was statistically significant (Z=-1.776,P =0.035).Conclusions IgG4-RD may be the reason of liver injury.There are no significant differences in clinical charateristics,serum parameters and inflammation degree in liver tissue between patients with or without IgG4 positive cells infiltration.

Vessel wall magnetic resonance imaging (VW-MRI) is a non-invasive imaging method for evaluating intracranial atherosclerotic plaques,which can effectively distinguish the morphology and composition of atherosclerotic plaques.This article reviews the application of VW-MRI in the evaluation of intracranial atherosclerotic plaque.

Objective: To analyze the mortality of upper gastrointestinal cancer in Cixian County, Hebei Province, China, over the past 33 years, and provide evidence for the prevention and treatment of such cancer. Methods: According to the cancer registration regulations, changes in the mortality of upper gastrointestinal cancer were collected, sorted and evaluated, and the trends in the mortality of upper gastrointestinal cancer were analyzed using the cancer registration data accumulated by the Cixian cancer Registration Office between January 1, 1983, and December 31, 2015. The percentage changes in crude mortality, standardized mortality in China, and the standardized worldwide mortality were calculated. The annual percent change of mortality was estimated using a linear regression model of the adjustment rate. Results: Over the 33-year period in Cixian County, the average crude mortality of upper gastrointestinal cancer was 119.31/100,000, including 149.21/100,000 for males and 88.40/100,000 for females. The standardized mortality rate in China was 160.85/100,000, including 227.00/100,000 males and 108.07/100,000 females. The worldwide standardized mortality rate was 162.39/100,000, including 228.52/100,000 males and 109.30/100,000 females. Conclusions: The mortality of upper gastrointestinal cancer displayed a decreasing trend, but it still had the highest mortality rate of malignant tumors in Cixian County. Age-specific mortalities were increasing along with the rise of age.

Objective To investigate the genotypes of host killing genes and their single nucleotide polymorphisms (SNPs). Methods Three hundred and twenty strains of Escherichia coli that collected from the First Affiliated Hospital of Wenzhou Medical College were analyzed. The first sample ( E1 ) contains 160 strains isolated during the years from 2002 to 2003. The second sample (E2) contains 160 strains covering the years from 2008 to 2009. The plasmids of Escherichia coli were extracted by alkaline lysis method. Solexa/Illumina sequencing technology was used to sequence plasmids metagenome. Solexa Genome Analysis System and Soap programs were used to analyze gene distribution, SNPs and lineage-specific mutations. Results 11 077 768 reads were generated and 0. 045% of them can map to the reference sequences from El sample. Whereas 9 377 792 reads were generated and 0. 053% of which mapped to the reference from E2 sample. There are nine host killing genes identified in the two samples, of which hok gene is the most prevalent. A total of 29 SNP sites dispersed in five genes of the two samples. Approximately 33% of them were non-synonymous mutations. One position of A and G is the most prevalent polymorphism. Conclusion The known nine genotypes of host killing genes were all identified in plasmids of Escherichia coli in Wenzhou. hok gene showed the highest frequency. There were SNPs in five genotypes.

Objective To evaluate the individualized 3D) printed drilling guide we developed and used for placement of C1/2 pedicle screws in the clinical treatment of fracture and dislocation of the atlantoaxial joint.Methods From January 2014 to June 2016,we treated a total of 17 patients with fracture and dislocation of the atlantoaxial joint.All the cervical CT data of the patients were imported into the digital orthopaedic workstation for 3D reconstruction,data modeling and 3D printing to design and manufacture individualized atlantoaxial vertebral guide templates.Intraoperatively,C1 and C2 pedicle screws were placed under the guide of individualized 3D printed drilling template.Cervical short-segment fixation and fusion were conducted for the patients.Postoperatively,regular clinical and radiographic follow-ups were carried out.Results No serious complications like injury to spinal cord and vertebral artery happened due to failed placement of C1/2 pedicle screws.The operation time ranged from 136 to 222 min (average,168.0 rmin);the intraoperative blood loss ranged from 260 to 556 mL (average,356.0 mL).The 17 patients were followed up for 6 to 36 months (average,13.5 months).The patients obtained bony union after 4 to 6 months (average,4.8 months).At the final follow-up,according to ASIA92 scoring system,the average sensory score was improved significantly from preoperative 7.4 + 3.2 to postoperative 13.1 + 5.9,and the average motor score was improved significantly from preoperative 5.3 + 3.1 to postoperative 11.7 + 5.1 (P ＜ 0.05).No such complications as infection or implant failure occurred after operation.Conclusion Individualized 3D printed drilling guide for implantation of atlantoaxial pedicle screws can make the complicate and risky placement become accurate,safe and simple.