[The surgical classification and surgical strategy for en bloc resection of spine tumor]

En bloc resection of spine tumor is the essential treatment method for primary malignant spine tumor,primary aggressive spine tumor and solitary spine metastasis.It can achieve good local control and improve the prognosis.However,given the complex anatomic structure and major adjacent tissue and organ of the spine,en bloc resection of spine tumor remains the research hotspot in surgical treatment of spine tumor.On the basis of adequate surgical classification and surgical strategy,experienced surgical team for spine tumor can achieve good surgical margin while decreasing the morbidity of the en bloc resection of spine tumor.However,the details of surgical classification and surgical strategy require further study.

[Three cases of occupational acute trimethyltin chloride poisoning]

Trimethyltin chloride is a highly toxic substance, which is absorbed through respiratory tract, skin and digestive tract, with central nervous system injury as the main clinical manifestations, and can be accompanied by damage to various organs. In this paper, the treatment process of 3 patients with acute trimethyltin chloride poisoning was reviewed, and their clinical manifestations, auxiliary examination, diagnosis and treatment were analyzed. Three patients were misdiagnosed as mental abnormality, encephalitis, and hepatic encephalopathy in different hospitals in the early stage of medical treatment, suggesting that clinicians should pay attention to the occupational contact history of poisoned patients and conduct toxicant detection in time to avoid misdiagnosis and mistreatment.

[Research progress on cirrhosis reversal and recompensation]

Previously, liver lesions in cirrhosis were considered irreversible, especially because the condition aggravated gradually after entering the decompensated phase, thus making it difficult to return to the compensated phase. At present, more and more evidence shows that some patients with decompensated liver cirrhosis can be recompensated after the cause is controlled and complications are managed. This article explores the research progress related to LC reversal and recompensation from three aspects: liver histopathology, liver function, and clinical complications.

SOX2-associated signaling pathways regulate biological phenotypes of cancers

SOX2 is a transcription factor involved in multiple stages of embryonic development. In related reports, SOX2 was found to be abnormally expressed in tumor tissues and correlated with clinical features such as TNM staging, tumor grade, and prognosis in patients with various cancer types. In most cancer types, SOX2 is a tumor-promoting factor that regulates tumor progression and metastasis primarily by maintaining the stemness of cancer cells. In addition, SOX2 also regulates the proliferation, apoptosis, invasion, migration, ferroptosis and drug resistance of cancer cells. However, SOX2 acts as a tumor suppressor in some cases in certain cancer types, such as gastric and lung cancer. These key regulatory functions of SOX2 involve complex regulatory networks, including protein-protein and protein-nucleic acid interactions through signaling pathways and noncoding RNA interactions, modulating SOX2 expression may be a potential therapeutic strategy for clinical cancer patients. Therefore, we sorted out the phenotypes related to SOX2 in cancer, hoping to provide a basis for further clinical translation.

[Applications of collagen extrafibrillar demineralization in dentin bonding]

The existing dentin bonding systems based on acid-etching technique lead to the loss of both extrafibrillar and intrafibrillar minerals from dentin collagen, causing excessive demineralization. Because resin monomers can not infiltrate the intrafibrillar spaces of demineralized collagen matrix, degradation of exposed collagen and resin hydrolysis subsequently occur within the hybrid layer, which seriously jeopardizing the longevity of resin-dentin bonding. Collagen extrafibrillar demineralization can effectively avoid the structural defects within the resin-dentin interface caused by acid-etching technique and improve the durability of resin-dentin bonding, by preserving intrafibrillar minerals and selectively demineralizing extrafibrillar dentin. The mechanism and research progress of collagen extrafibrillar demineralization in dentin bonding are reviewed in the paper.

[Clinical characteristics of 500 hospitalized patients with liver cirrhosis: a retrospective analysis from a tertiary hospital in Beijing]

Objective: To understand the clinical characteristics of hospitalized patients with liver cirrhosis, so as to provide theoretical basis for disease diagnosis and treatment, formulation of intervention measures, and improve the level of disease diagnosis and treatment. Methods: Hospitalized patients who were initially diagnosed with liver cirrhosis at Peking University First Hospital from August 2017 to December 2018 were selected retrospectively as the research objects. Liver cirrhosis demographic data, etiology, severity classification, incidence of complications, diagnosis and prognosis were recorded. Statistical analysis was performed using SPSS software. Results: Among all liver cirrhosis cases, there were 291 males and 209 females, with a male-to-female ratio of 1.4:1 and an age of 59.5±12.9 years as at August 2017 to December 2018. HBV infection, alcoholic liver disease, and autoimmune liver diseases were the most common etiology of liver cirrhosis. HBV infection alone, HBV infection combined with other factors, alcoholic liver disease alone, alcoholic liver disease combined with other factors, autoimmune liver disease alone, and autoimmune liver disease combined with other factors were presented in 163 (32.6%), 57 (11.4%), 47 (9.4%), 63 (12.6%), 85 (17.0%), and 22 (4.4.0%) cases, respectively. Ascites (221 cases, 44.2%), followed by esophagogastric varices (214 cases, 42.8%), and other including hypersplenism (137 cases), liver cancer (126 cases), upper digestive system tract hemorrhage (66 cases), hepatic encephalopathy (40 cases), infection (37 cases), portal vein thrombosis (23 cases), hepatorenal syndrome (20 cases) were the most common complications. The most common site of infection was the abdominal cavity (20 cases), accounting for 54.1%; followed by respiratory tract infection (8 cases), accounting for 21.6% in patients with liver cirrhosis with concurrent infection. Among them, there were 32 cases of bacterial infection alone, one case of bacterial infection combined with fungal infection, one case of bacterial infection combined with viral infection, and three cases of unknown pathogens. There were 69 cases in Child Pugh grade C, and the average hospitalization times were 12.6 days in terms of prognosis. There were total seven cases of death, of which five cases were due to upper gastrointestinal hemorrhage and two due to hepatic encephalopathy. Conclusion: HBV infection, ascites, and upper gastrointestinal bleeding were the most common etiologies, complications, and causes of death in patients with liver cirrhosis at our hospital.

[Clinical features of Epstein-Barr virus infection associated to liver injury in adolescents and adults]

Epstein-Barr virus (EBV) infection is closely associated to liver injury with diverse clinical features in adolescents and adults. It is often manifested as infectious mononucleosis syndrome, sometimes causing self-limited acute hepatitis, with mild to moderate elevation of liver transaminases, and relative increase in age-related conditions. EBV infection can also cause cholestatic hepatitis, with elevated alkaline phosphatase and γ-glutamyltransferase as the main manifestations, accompanied by varying degrees of jaundice. A small number of patients with severe EBV infection may experience liver failure, and if left untreated in time, it may lead to high mortality. In addition, EBV infection is also associated with chronic hepatitis, liver cirrhosis, autoimmune liver disease, etc.

[Effects of programmed death receptor-1 antibody in patients with hepatitis B-associated liver cancer]

Objective: To investigate the effect of programmed death receptor (PD)-1 antibody therapy in patients with hepatitis B-associated liver cancer. Methods: Data of 29 chronically infected HBV patients with liver cancer who received PD-1 antibody combined with tyrosine kinase inhibitor in the Department of Infectious Diseases of the Fifth Medical Center of PLA General Hospital from March 2020 to January 2021 were selected. At the same time, all of the above-mentioned hepatitis B virus (HBV) patients were treated with nucleos(t)ide analogues. Patients clinical diagnostic data, laboratory test results, tumor response and the incidence of adverse reactions were collected retrospectively to understand the overall safety, therapeutic anti-tumor effect, HBV changes condition and the correlation between HBV changes and anti-tumor PD-1 antibody efficacy, high viral load treatment condition, and HBV reactivation safety issues. Statistical analysis was performed by non-parametric rank sum test. Results: Therapeutic anti-tumor effect and safety profile were good in patients. The complete remission rate was reached 27.6%. Adverse reactions were mostly mild, and the incidence of serious adverse reactions was low. After 12 weeks of follow-up, HBV DNA and hepatitis B surface antigen (HBsAg) was quantitatively decreased (P < 0.05). HBV DNA and HBsAg were decreased more significantly in patients with progressive disease (PD), stable disease (SD) and partial response (PR) (P < 0.05). Five patients with HBV DNA ≥ 10(4) IU/ml had responded well to the tumor treatment without serious adverse reactions. One patient had a slight increase in HBV DNA and alanine aminotransferase, while there was no HBV reactivation and correlated liver damage. Conclusion: Patients with HBV-associated liver cancer who received combined therapy have good anti-tumor efficacy and safety profile. PD-1 treatment has a certain effect on HBV. Compared with non-responders, patients with tumor response have better antiviral treatment efficacy. The safety of treatment in patients with high viral load is manageable, and there are no safety issues related to HBV reactivation.

[High frequency hearing loss detection rate in occupational noise exposed workers in China: a Meta-analysis]

Objective: A Meta-analysis was used to evaluate the high frequency hearing loss detection rate, its area and time distributions in occupational noise exposed workers in China to provide evidence for the prevention and control of occupational noise-induced deafness. Methods: From February to April 2020, the number of hearing tests and the number of binaural high frequency average hearing threshold ≥40 dB of workers exposed to noise in key occupational disease monitoring and occupational health risk assessment project in China was collected from China National Knowledge Infrastructure (CNKI) , VIP database and PubMed database. The retrieval time was set from the establishment of the database to February 28, 2020. The R 3.6.2 software was used to calculate the pooled high frequency hearing loss detection rate. Results: A total of 28 studies, included 34 data and 1259571 occupational noise exposed workers, were enrolled. The articles covered 16 provinces in 2015-2018. The pooled high frequency hearing loss detection rate in occupational noise exposed workers was 9.45% (95%CI: 7.64%-11.64%) . The high frequency hearing loss detection rate (10.54%) was higher in 2018 than other years (2017: 10.17%, 2016: 9.21%, 2015: 7.88%) . The high frequency hearing loss detection rate (12.23%) was higher in central China than in eastern (10.21%) , western (7.91%) and north-eastern (5.21%) China. Conclusion: The overall high frequency hearing loss detection rate in occupational noise exposed workers is generally high in China. It is important to strengthen the hearing protection in occupational noise exposed workers to facilitate the occupational noise-induced deafness prevention and control in China.

[Research progress and prospect of liver cirrhosis]

Liver cirrhosis is the final stage of many chronic liver diseases, and is still a heavy disease burden. The proportion of liver cirrhosis caused by the hepatitis B virus is declining, while that caused by the non-alcoholic fatty liver disease (metabolic-associated fatty liver disease) is rising. Several predictive models and techniques such as transient elastography have been used for the early non-invasive evaluation of liver cirrhosis. Effective etiological treatment and complication management are the possible key to reverse and recompense liver function during liver cirrhosis treatment. In recent years, the effectiveness and availability of anti-hepatitis B and C virus drugs have been significantly improved, which provides the basis for effective etiological treatment of liver cirrhosis. However, there is still a lack of etiological treatment measures for non-alcoholic fatty liver disease. Therefore, in addition to focusing on common complications, we should also manage "rare" complications. This article reviews the changes in epidemiological characteristics, the update of the natural history concepts, diagnostic evaluation methods, and the treatment measures for liver cirrhosis.

[Retrospective analysis of risk factors of liver cirrhosis combined with overt hepatic encephalopathy: a single -center case-control study]

Objective: To explore the risk factors of overt hepatic encephalopathy (OHE) in patients with liver cirrhosis. Methods: A retrospective study was designed. Patients with liver cirrhosis combined with /without OHE who were hospitalized to our hospital during the same period were selected as the case/control group. Clinical and laboratory data of both groups of patients were compared to analyze the risk factors affecting the occurrence of OHE. SPSS software was used for statistical analysis. A t-test or rank-sum test was used to compare the measurement data. Chi-square test or Fisher's exact probability method was used to compare the count data. Logistic regression was used for multivariate analysis. Results: A total of 500 patients with liver cirrhosis diagnosed in our hospital from August 2017 to December 2018 were selected as the case group, and 40 cases with cirrhosis without OHE who were hospitalized during the same period were randomly selected as the control group. The gender composition and age of the case and control group were comparable. Viral hepatitis (mainly hepatitis B) was the main etiology of liver cirrhosis in both groups. There were 52.5% patients in the case group and 57.5% patients in the control group, respectively. Alcoholic liver disease, autoimmune liver disease and so on were the other included causes. With regard to blood biochemical indicators, the serum creatinine levels of both groups were comparable, but in the case group, the serum total bilirubin level was higher (34.30 μmol / L vs. 18.65 μ mol/L, Z = -3.185, P < 0.05), while the serum sodium level was lower (137.00 mmol/L vs. 140.08 mmol/L, Z = -2.348, P < 0.05), and the prothrombin time was longer (14.60 s vs. 12.20 s) s. 078, P < 0.05), and international normalized ratio (1.33 vs. 1.07, Z = - 5.632, P < 0.05), and serum albumin level (30.6 g/L vs. 35.6 g/L, t = 3.386, P < 0.05) was lower. In terms of complications, patients in the case group had a higher proportion of combined gastrointestinal bleeding (30.0% vs. 10.0%, χ(2) = 5.000, P < 0.05), ascites (87.5% vs. 30.0%, χ(2) = 27.286, P < 0.05) and secondary infection (32.5% vs. 10.0%, χ(2) = 7.813, P < 0.05). In terms of severity classification, the proportion of Child-Pugh C in the case group was higher (62.5% vs. 10.0%, χ(2) =26.593, P < 0.05). In terms of outcome, there were 3 deaths in the case group and no deaths in the control group. Multivariate analysis showed that Child-Pugh class C (OR = 12.696), and combined ascites (OR = 10.655) were an independent risk factor for OHE in patients with liver cirrhosis. Conclusion: Our single-center retrospective clinical study shows that patients with cirrhosis combined with OHE are more critical and have more complications. In order to promptly diagnose and treat OHE, more attention should be paid to patients with combined ascites and Child-Pugh class C.

Novel Naturally Occurring Mutations of Enterovirus 71 Associated With Disease Severity

Infection with the re-emerging enterovirus 71 (EV-A71) is associated with a wide range of disease severity, including herpangina, encephalitis, and cardiopulmonary failure. At present, there is no FDA-approved therapeutics for EV-A71. Early diagnosis for the high-risk children is the key to successful patient care. We examined viral genome sequences at the 5′ untranslated region (UTR) and the capsid protein VP1 from 36 mild and 27 severe cases. We identified five EV-A71 mutations associated with severe diseases, including (1) the 5′ UTR mutations C580U, A707G, C709U; (2) a VP1 alanine-to-threonine mutation at position 280 (280T), and (3) a VP1 glutamic acid-to-(non-glutamic acid) at position 145 [145(non-E)]. SCARB2 is a known entry receptor for EV-A71. Based on a recent cryoEM structure of the EV-A71-SCARB2 binding complex, VP1-280T is near the binding interface between the VP1-VP2 complex and its entry receptor SCARB2. A de novo created hydrogen bonding between the mutant VP1-280T and the VP2-139T, could help strengthen a web-like interaction structure of the VP1-VP2 complex. A stabilized loop turn of VP2, once in contact with SCARB2, can enhance interaction with the host SCARB2 receptor for viral entry. Our findings here could facilitate early detection of severe cases infected with EV-A71 in clinical medicine. In addition, it opens up the opportunity of functional studies via infectious cDNA cloning, site-directed mutagenesis, and animal models in the future.

Association of Carbonic Anhydrase 9 Polymorphism and the Epithelial Growth Factor Receptor Mutations in Lung Adenocarcinoma Patients

Carbonic anhydrase 9 (CA9) plays a vital role in lung cancer progression. The current study explored the effect of CA9 gene polymorphisms and the epidermal growth factor receptor (EGFR) mutations on the clinicopathological characters of lung adenocarcinoma. In this study, three loci of CA9 single nucleotide polymorphism (SNP) (rs2071676 A>G, rs3829078 A>G, and rs1048638 C>A) were genotyped using the TaqMan allelic discrimination method in 193 EGFR wild type individuals and 281 EGFR mutation subjects. After adjusting for age, gender, and cigarette smoking status in logistic regression, all three CA9 SNPs illustrated a non-significant difference for the distribution between the EGFR wild type group and EGFR mutation group. Nevertheless, a significantly lower rate of CA9 SNP rs2071676 AG (adjusted odds ratio (AOR): 0.40, 95% confidence interval (CI): 0.16-0.95, p = 0.039) and AG+GG (AOR: 0.43, 95% CI: 0.18-0.98, p = 0.046) were found in the male population with L858R EGFR mutation compared to men with EGFR wild type. In addition, the CA9 SNP rs2071676 AG+GG genotype were significantly correlated to the lower tumor stage of lung adenocarcinoma in the whole study population (p = 0.044) and EGFR wild type individuals (p = 0.033). For the male population, the presence of CA9 SNP rs2071676 AG+GG genotype was also correlated to a lower tumor stage (p = 0.037) and fewer lymph node invasion (p = 0.003) in those with EGFR wild type. In conclusion, the existence of CA9 SNP rs2071676 is associated with the rate of EGFR L858R mutation in males. Furthermore, the CA9 SNP rs2071676 is correlated to lower tumor stage and lower risk for developing lymph node metastasis in lung adenocarcinoma, mainly in the EGFR wild type.

[Knockdown of MTA1 inhibits the proliferation and apoptosis of esophageal cancer cells]

Objective: To investigate the effects of metastasis associated gene 1 (MTA1) expression on the proliferation and apoptosis of human esophageal cancer Eca109 cells. Methods: MTA1 siRNA was transfected into human esophageal cancer Eca109 cells, and the control group and blank group were set up. The expression of MTA1 in Eca109 cells with different treatment was detected by real-time fluorescent quantitative PCR (RT-PCR) and western blot. The proliferation of Eca109 cells was detected by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2H tetrazolium bromide (MTT) assay. The cloning formation ability of Eca109 cells was detected by plate cloning assay. The apoptosis of Eca109 cells were detected by flow cytometry. The expression of proliferating cell nuclear antigen (PCNA) and apoptosis-related proteins, including cleaved caspase-3 and total caspase-3 protein in Eca109 cells were detected by western blot. Results: After 48 hours of transfection, RT-PCR result showed that the relative expression levels of MTA1 mRNA in Eca109 cells in the blank group, control group, and siRNA group were 1.00±0.10, 0.98±0.09 and 0.21±0.03, respectively. The expression of MTA1 mRNA in siRNA group was significantly inhibited (P<0.05), while no significant difference of MTA1 mRNA expression between the blank group and the control group has been found (P>0.05). Western blot results were consistent with those of RT-PCR. MTT array results showed that, compared with the blank group and transfection group, the absorbance values of Eca109 cells in siRNA group were dramatically reduced at 48, 72, and 96 h (all P<0.05). There were no significant differences of absorbance values between the blank group and the control group at 48, 72, and 96 h (all P>0.05). The results of the plate colony formation test showed that the number of colony formation in the blank group and control group were 58.64±6.86 and 60.02±7.04, respectively, significantly higher than 18.10±3.16 in siRNA group (P<0.05), while there was no significant difference between the blank group and control group (P>0.05). Flow cytometry results showed that the apoptosis rates in the blank group and control group were (2.13±0.54)% and (2.27±0.61)%, respectively, significantly lower than (32.61±5.28)% in siRNA group (P<0.05), while there was no significant difference between blank group and control group (P>0.05). Western blot results showed that the expression of PCNA protein was down-regulated while cleaved caspase-3 protein expression was upregulated in siRNA group, compared to the control group and blank group (P<0.05). Conclusions: Inhibition of MTA1 expression can inhibit the proliferation of Eca109 cells and induce apoptosis. This process may be related to the down-regulation of PCNA protein expression and activation of caspase-3 protein expression.

[Role of artificial intelligence in the diagnosis and treatment of gastrointestinal diseases]

The rapid development of computer technologies brings us great changes in daily life and work. Artificial intelligence is a branch of computer science, which is to allow computers to exercise activities that are normally confined to intelligent life. The broad sense of artificial intelligence includes machine learning and robots. This article mainly focuses on machine learning and related medical fields, and deep learning is an artificial neural network in machine learning. Convolutional neural network (CNN) is a type of deep neural network, that is developed on the basis of deep neural network, further imitating the structure of the visual cortex of the brain and the principle of visual activity. The current machine learning method used in medical big data analysis is mainly CNN. In the next few years, it is the developing trend that artificial intelligence as a conventional tool will enter the relevant departments of medical image interpretation. In addition, this article also shares the progress of the integration of artificial intelligence and biomedicine combined with actual cases, and mainly introduces the current status of CNN application research in pathological diagnosis, imaging diagnosis and endoscopic diagnosis for gastrointestinal diseases.

Association of Drug Metabolic Enzyme Genetic Polymorphisms and Adverse Drug Reactions in Patients Receiving Rifapentine and Isoniazid Therapy for Latent Tuberculosis

Weekly rifapentine and isoniazid therapy (3HP) is the most frequent treatment for latent tuberculosis infection (LTBI). However, the association between major adverse drug reactions (ADRs) and drug metabolic enzyme single-nucleotide polymorphisms (SNPs) remains unclear. In this study, 377 participants who received the 3HP regimen were recruited and examined for genotyping of CYP5A6, CYP2B6, CYP2C19, CYP2E1, and NAT2 SNPs. In our study, 184 participants (48.4%) developed ADRs. Moreover, CYP2C19 rs4986893 (TT vs. CC+CT, odds ratio [OR] [95% CI]: 2.231 [1.015-4.906]), CYP2E1 rs2070676 (CC vs. CG+GG, OR [95% CI]: 1.563 [1.022-2.389]), and CYP2E1 rs2515641 (CC vs. CT+TT, OR [95% CI]: 1.903 [1.250-2.898]) were associated with ADR development. In conclusion, CYP2C19 and CYP2E1 SNPs may provide useful information regarding ADRs in LTBI patients receiving the 3HP regimen.

Visual and rapid detection of Plesiomonas shigelloides using loop-mediated isothermal amplification method

Plesiomonas shigelloides is a common pathogen of aquatic animals and can pose a certain hazard to aquaculture. Here, we aimed to develop a loop-mediated isothermal amplification (LAMP) method for the visual detection of P. shigelloides to aid the diagnosis of infections caused by this pathogen in aquatic animals. We used LAMP to amplify P. shigelloides DNA and combined it with calcein or nucleic acid dipstick assay (NADA) to visualize the amplified products. The optimal LAMP amplification temperature was 64°C, and the reaction lasted for 50 min. The limit of detection of recombinant plasmids containing the target gene using the LAMP method was 2·0 × 10² copies per μl, which is ten times higher than that using conventional polymerase chain reaction (PCR). LAMP products could be visualized without agarose gel electrophoresis. We tested 85 fish specimens using the established LAMP method and conventional PCR. The detection rate was 42·4% using the LAMP method and 34·1% using conventional PCR. Based on our results, the LAMP method combined with calcein or NADA is a rapid, specific, sensitive and accurate method for visual detection of fish-derived P. shigelloides and can be used for the laboratory diagnosis of infections caused by it. SIGNIFICANCE AND IMPACT OF THE STUDY: The combination of loop-mediated isothermal amplification (LAMP) and calcein and nucleic acid dipstick assay (NADA) provided a rapid, specific and sensitive method for detecting Plesiomonas shigelloides, which is an important pathogen that causes diseases in aquatic animals worldwide. In the present study, the LAMP method showed a higher detection rate than conventional PCR for P. shigelloides using templates from 85 fish specimens. Thus, the LAMP method could be a reliable and convenient tool for diagnosing diseases in aquatic animals in the laboratory.

[Features of a modified WHO/UCLA AVLT performance in amnestic mild cognitive impairment and mild Alzheimer's disease]

Objective: To compare the features of a modified WHO/UCLA AVLT performance in the cognitive normal, amnestic mild cognitive impairment (aMCI) and mild Alzheimer's disease (mild AD) patients. Method: A total of 105 cases of cognitivenormal (CN), 48 aMCI and 50 mild AD patients were included between 2016 and 2018. All subjects undertook detailed neuropsychological tests and brain MRI/CT scan. Results: The total score of five learning trials in CN, aMCI and AD groups were 53.9±6.9, 34.6±8.3 and 23.7±6.2, respectively (P<0.001). The score of 20-min delay recallwere 12.5±1.6, 4.3±3.0 and 0.6±1.0, respectively (P<0.001) in three groups. The score of cued recall were 13.0±1.4, 7.0±2.4 and 2.6±2.0, respectively (P<0.001). The score of 20-min delay recall had the largest effect sizes between CN and aMCI groups (Cohen'd=3.8, 95%CI,3.3-4.4), and CN and mild AD groups (Cohen'd=8.1, 95%CI 7.1-9.1). Cued recall had the largest effect size between aMCI and mild AD groups (Cohen'd=2.04, 95%CI 1.5-2.5). The scores of learning total score, 20-min delay recall, cued recall and recognition had the strong relationships with the scores of mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA) , but obtaining moderate relationships with Boston naming test and trail making test (TMT) and weak relationships with digit span and figure copy. Age and education had no relationship with the main indices of this modified AVLT. Conclusions: The modified WHO/UCLA AVLT is still an age and education fair test to assess memory domain function. Qualitative analysis of AVLT profiles may be useful to differentiate the CN, aMCI and mild AD in Chinese sample.

[Influence of proximal two-wall bone defect on periodontal ligament stresses under normal occlusal forces]

Objective: To study the influence of two-wall bone defect on periodontal ligament stresses under normal occlusal forces, and to analyze the influence of depth and width of bone defect to periodontal ligament stresses. Methods: Three-dimensional finite element models of teeth, periodontal ligament and alveolar bone were created based on cone beam CT images. Proximal two-wall bone defect with different depths (bone defect occupies one third, two thirds, and full length of root) and widths (bone defect occupies one fourth, two fourths, three fourths and full width of buccal lingual width) were simulated by modifying the elastic modulus of elements within defect areas. Occlusal forces with magnitudes of half of the maximum occlusal forces were applied to the model at an angle of 45° to the long axis of tooth, and equivalent stresses of periodontal ligament were analyzed. Results: In the model of no bone defect, the equivalent stresses of periodontal ligament of incisors, canines, premolars and molars were 2.88, 2.31, 8.67 and 7.53 MPa respectively. The equivalent stresses of periodontal ligament increased with the enlargement of depth and width of bone defect. The equivalent stresses of periodontal ligament with maximum bone defect in both depth and width for incisors, canines, premolars and molars were 4.47, 3.62, 11.66 and 8.72 MPa respectively. In the model of width of bone defect was consistent and bone defect develops vertically, the increments of equivalent stresses of periodontal ligament were significantly greater in the early stage bone defect model (from no defect to one third of root length bone defect) than that in the later stage bone defect model (from two thirds to full length of root length bone defect). In the model of bone defect depth was consistent and bone defect develops transversely, the increments of equivalent stresses of periodontal ligament in the early stage bone defect model (from no defect to one fourth of buccal lingual width bone defect) were significantly smaller than that in the later stage bone defect model (from three fourths to full width of buccal lingual width bone defect). Conclusions: Bone defect with shallow depth and that with large width would increase periodontal ligament stresses. Therefore, more attention should be paid to occlusion evaluation and adjustment for teeth with shallow and wide two-wall bone defect.

High-dose dexamethasone or all-trans-retinoic acid restores the balance of macrophages towards M2 in immune thrombocytopenia

Essentials M1/M2 imbalance is involved in many autoimmune diseases, and could be restored. The expressions and functions of M1 and M2 were investigated in an in vitro culture system. A preferred M1 polarization is involved in the pathogenesis of immune thrombocytopenia (ITP). High-dose dexamethasone or all-trans-retinoic acid restores M1/M2 balance in ITP patients.

SUMMARY

Background Immune thrombocytopenia (ITP) is an autoimmune disorder. Deficiency of immune tolerance in antigen-presenting cells and cross-communication between antigen-presenting cells and T cells are involved in the pathogenesis of ITP. Macrophages can polarize into proinflammatory M1 or anti-inflammatory M2 phenotypes in response to different environmental stimuli, and have diverse immunologic functions. Objectives To investigate the M1/M2 imbalance in ITP and whether high-dose dexamethasone (HD-DXM) or all-trans-retinoic acid (ATRA) could restore this imbalance. Methods The numbers of M1 and M2 macrophages in the spleens of ITP patients and patients with traumatic spleen rupture were analyzed by immunofluorescence. Monocyte-derived macrophages were cultured and induced with cytokines and drugs. The expression of M1 and M2 markers and functions of M1 and M2 macrophages before and after modulation by HD-DXM or ATRA were evaluated with flow cytometry and ELISA. Results There was preferred M1 polarization in ITP spleens as compared with healthy controls. Monocyte-derived macrophages from ITP patients had increased expression of M1 markers and impaired immunosuppressive functions. Either HD-DXM or ATRA corrected this imbalance by decreasing the expression of M1 markers and increasing the expression of M2 markers. Moreover, HD-DXM-modulated or ATRA-modulated macrophages suppressed both CD4+ and CD8+ T-cell proliferation and expanded CD4+ CD49+ LAG3+ type 1 T-regulatory cells. HD-DXM or ATRA modulated macrophages to shift the T-cell cytokine profile towards Th2. Treating patients with HD-DXM or ATRA revealed that macrophages induced from responders showed a predominant M2-like phenotype and immunosuppressive function. Conclusions Aberrant macrophage polarization is involved in the pathogenesis of ITP. Either HD-DXM or ATRA is able to correct this imbalance.

Cardiotoxicity evaluation of nine alkaloids from Rhizoma Coptis

PURPOSE

Alkaloids derived from Rhizoma Coptis (RC) has been widely applied to clinical treatments in China. However, the toxicity of RC and the alkaloids from RC remained controversial. The research is designed to clarify the cardiotoxic compounds found in RC.

METHODS

In this study, the real-time cellular analysis cardio system and the high-content analysis were applied to monitor the function of cardiomyocytes (CMs) in the treatment of nine alkaloids in RC. Luciferase-coupled adenosine triphosphate (ATP) assay was used to detect cell viability.

RESULTS

The results showed that berberine, palmatine, berbamine, and oxyberberine were cardiotoxic, which resulted in arrhythmia and cardiac arrest on CMs in a time- and dose-dependent manner. Meanwhile, berbamine and oxyberberine caused shrinkage and detachment on CMs at 10 μM. Cytotoxicity was induced by these two compounds with decline in cell index and ATP depletion. Cardiotoxicity or cytotoxicity was not observed in the other five alkaloids within 10 μM.

CONCLUSION

For the first time, the cardiotoxicity of the nine alkaloids was evaluated to clarify the cardiotoxic components in RC. Furthermore, the experimental evidences were provided to support the safety of drug application.

[The efficacy of large spot indirect ophthalmoscopy laser alone or combined with systemic chemotherapy in retinoblastoma therapy]

Objective: To evaluate the efficacy of large spot indirect ophthalmoscopy laser alone or combined with systemic chemotherapy in the treatment of early and middle stage retinoblastoma. Methods: Retrospective series case study. Clinical data of 21 patients (22 eyes) who were diagnosed as retinoblastoma (RB) in Peking University People's Hospital from March 2009 to August 2014 were collected. Medical and family history, ocular ultrasound, orbital and cranial MRI or CT examination of RB Children were detailed recorded. Ocular examination and laser treatment were performed under general anesthesia, once every 3-4 weeks until the tumor was under control. The observation period was at least 3 months after the last treatment. The ocular examination included intraocular pressure measurement, anterior segment and fundus examination and the fundus photography with Retcam. Laser therapeutic instrument was large spot indirect ophthalmoscopy laser of 810nm wavelength. Results: Of the 21 children, 16 were male and 5 were female. The range of age was 3 to 82 months averaged 17.3 months. Among 22 eyes, four with small tumor, eight with medium tumor, and ten with large tumor. Two eyes underwent laser treatment only and 20 eyes underwent laser treatment combined with systemic chemotherapy. During the average observation period of 33.9 months, 15 tumors were treated successfully, but 7 failed. The total success rate was 68.2%. The number and success rate of small, medium and large tumor eyes were 4 (100%), 5 (62.5%) and 5 (50%), respectively. There was one case of tumor brain metastases, and the classification of contralateral eye of the child was E phase.

COMPLICATIONS

Iris burns happened in one eye, obvious vitreous proliferation in one eye and mild vitreous hemorrhage occurred in two eyes, which did not affect the treatment of laser. However, obvious tumor hemorrhage happened in two eyes and affected laser therapy. There was no complicated cataract, iatrogenic retinal hole and tumor intravitreal implant caused by laser blasting effect. Conclusions: Indirect ophthalmoscope laser in 810-nm diode laser with large-spot alone or combined with systemic chemotherapy may be effective treatment for retinoblastoma in earlier than stage C of international classification. It is suitable for large and multiple retinoblastoma.(Chin J Ophthalmol, 2016, 52: 745-748).

[Profiles of cognitive and language impairment of logopenic and non-fluent variant of primary progressive aphasia]

OBJECTIVE

To decipher the cognitive and linguistic feature of logopenic variant primary progressive aphasia (lv-PPA) and nonfluent variant primary progressive aphasia (nfv-PPA) and to explore the extent to which cognitive and language impairment contribute to the dysfunction of activity of daily living(ADL).

METHODS

Seven lv-PPA and five nfv-PPA were enrolled in memory clinic of Xuanwu Hospital, Capital Medical University from January 2015 to January 2016 accordig to the international consensus criteria for PPA and its three subtypes. 20 age-matched normal controls (NC) were included. Both the patients and the NC completed a battery of neuropsychological test, lingusitic test and brain magnetic resonance imaging. All the patients conducted (11)C Pittsburgh compound B (PiB) PET imaging.

RESULT

Lv-PPA patients were characterized by deficits in lexical retrieval and long sentenses repetition, while nfv-PPA were with motor speech apraxia and phonetic distortion. Compared with nfv-PPA, lv-PPA patient displayed more severe cognitive deficit with younger onset of age (56±5 vs 61±5, P<0.05) , rapid decline of MMSE score within 1.5 years and pariental cortex dysfunctions such as ideomotor praxis, Gerstmann syndrome and contructional apraxia. Correlation analysis indicated that there was more significant association between pariental cortex dysfunction and ADL/mini-mental state examination(MMSE) than that of language deficit(r=-0.868, r=-0.922; r=0.312, r=-0.257). All seven lv-PPA were PiB-PET positive and five nfv-PPA were negative.

CONCLUSION

This study enriched the chinical and linguistic characterization of lv-PPA and nfv-PPA, which has implication for diagnosis, disease management and treatment for clinicians.

Psoralen reverses docetaxel-induced multidrug resistance in A549/D16 human lung cancer cells lines

Chemotherapy is the recommended treatment for advanced-stage cancers. However, the emergence of multidrug resistance (MDR), the ability of cancer cells to become simultaneously resistant to different drugs, limits the efficacy of chemotherapy. Previous studies have shown that herbal medicine or natural food may be feasible for various cancers as potent chemopreventive drug. This study aims to explore the capablility of reversing the multidrug resistance of docetaxel (DOC)-resistant A549 cells (A549/D16) of psoralen and the underlying mechanisms. In this study, results showed that the cell viability of A549/D16 subline is decreased when treated with psoralen plus DOC, while psoralen has no effect on the cell proliferation on A549 and A549/D16 cells. Furthermore, mRNA and proteins levels of ABCB1 were decreased in the presence of psoralen, while decreased ABCB1 activity was also revealed by flow cytometry. Based on these results, we believe that psoralen may be feasible for reversing the multidrug resistance by inhibiting ABCB1 gene and protein expression. Such inhibition will lead to a decrease in ABCB1 activity and anti-cancer drug efflux, which eventually result in drug resistance reversal and therefore, sensitizing drug-resistant cells to death in combination with chemotherapeutic drugs.

Performance of the international physical activity questionnaire (short form) in subgroups of the Hong Kong chinese population

BACKGROUND

The International Physical Activity Questionnaire (IPAQ-SF) has been validated and recommended as an efficient method to assess physical activity, but its validity has not been investigated in different population subgroups. We examined variations in IPAQ validity in the Hong Kong Chinese population by six factors: sex, age, job status, educational level, body mass index (BMI), and visceral fat level (VFL).

METHODS

A total of 1,270 adults (aged 42.9 ± SD 14.4 years, 46.1% male) completed the Chinese version of IPAQ (IPAQ-C) and wore an accelerometer (ActiGraph) for four days afterwards. The IPAQ-C and the ActiGraph were compared in terms of estimated Metabolic Equivalent Task minutes per week (MET-min/wk), minutes spent in activity of moderate or vigorous intensity (MVPA), and agreement in the classification of physical activity.

RESULTS

The overall Spearman correlation (ρ) of between the IPAQ-C and ActiGraph was low (0.11 ± 0.03; range in subgroups 0.06-0.24) and was the highest among high VFL participants (0.24 ± 0.05). Difference between self-reported and ActiGraph-derived MET-min/wk (overall 2966 ± 140) was the smallest among participants with tertiary education (1804 ± 208). When physical activity was categorized into over or under 150 min/wk, overall agreement between self-report and accelerometer was 81.3% (± 1.1%; subgroup range: 77.2%-91.4%); agreement was the highest among those who were employed full-time in physically demanding jobs (91.4% ± 2.7%).

CONCLUSIONS

Sex, age, job status, educational level, and obesity were found to influence the criterion validity of IPAQ-C, yet none of the subgroups showed good validity (ρ = 0.06 to 0.24). IPAQ-SF validity is questionable in our Chinese population.

First report of human infection by Rhodoplanes sp., Alphaproteobacteria in China

We isolated a novel strain of Alphaproteobacteria from a patient, who had medical history of chronic rhinitis for more than twenty years and recently experienced local skin abscess and ulcer. He eventually died of multiple organ failure due to multi-antibiotics resistance. We identified the microorganism by 16SrRNA sequencing and found that it belonged to the genus Rhodoplanes. It was named as Rhodoplanes sp. strain ZLJ-0. It is resumed that Rhodoplanes sp. strain ZLJ-0 might be an emerging human pathogen involving in unknown febrile conditions and could cause local infection of any tissues or organs. Differential diagnosis of febrile patients should be conducted in clinical practice and research on emerging pathogens of Alphaproteobacteria should be performed to determine the epidemiology, clinical symptoms and pathogenic features of these pathogens.

Ferrous chelator 2,2'-dipyridyl attenuates cerebral vasospasm after experimental subarachnoid haemorrhage in rabbits

The effect of 2,2'-dipyridyl (DP) on cerebral vasospasm was investigated in a double-injection rabbit model of subarachnoid haemorrhage (SAH). Thirty-six animals were divided between four groups: control (sham-operated), SAH (model alone), SAH + DP (the SAH model in which DP dissolved in dimethyl sulphoxide [DMSO] was injected once daily for 5 days into the cisterna magna), and SAH + DMSO (the SAH model in which DMSO [vehicle] was injected daily for 5 days). There were significant differences in the basilar artery luminal area, wall thickness, neurological deficit score and vasospasm index between the SAH + DP and SAH groups. There was a significant negative correlation between arterial luminal area and arterial wall thickness, and also between the neurological deficit score and vasospasm index. Cells that were positive for terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labelling (TUNEL) and p53 expression were significantly increased in the SAH + DMSO and SAH groups, but not in the SAH + DP group, versus controls. Thus, DP may attenuate cerebral vasospasm after SAH by suppressing p53-induced apoptosis in the cerebral vessels.

Virological response to antiviral therapy at week 12 indicates a great reduction of intrahepatic hepatitis B virus DNA and cccDNA in HBeAg-positive chronic hepatitis B patients

Early virological response is considered to be a predictor for the outcome of anti-hepatitis B virus (HBV) therapy. To analyze its correlation to intrahepatic HBV DNA and covalently closed circular DNA (ccc)DNA, 71 hepatitis B virus e antigen (HBeAg)-positive chronic hepatitis B patients were recruited: 34 patients were treated with lamivudine; 13 with interferon-alpha2b; and 24 with sequential therapy of lamivudine-interferon-alpha2b for 48 weeks. Intrahepatic HBV DNA and cccDNA load were measured at the baseline and at Week 48. Fifty-seven patients had virological response at Week 12. Median decreases of serum HBV DNA in patients with or without virological response at Week 12 were 4.0 log(10) (max. 6.2, min. 2.2) and 1.1 log(10) (max. 2.1, min. 0) (Z = -5.766, P = 0.0000), respectively. At Week 48 they were 4.1 log(10) (max. 7.4, min. 1.0) and 2.3 log(10) (max. 7.5, min. 0.3) (Z = -2.760, P = 0.006), respectively. For intrahepatic HBV DNA load they were 1.3 log(10) (max. 4.3, min. -1.2) and 0.6 log(10) (max. 3.5, min. -0.8), respectively, and for HBV cccDNA load they were 1.1 log(10) (max. 4.8, min. -0.5) and 0.5 log(10) (max. 3.0, min. -0.8) (Z = -2.097, P = 0.036), respectively at Week 48. Step-wise logistic regression analysis indicated that the baseline intrahepatic HBV DNA load effected virological response at Week 12 [odds ratio (OR) 0.405; 95% confidence interval (CI) 0.174-0.944; P = 0.036] and HBeAg seroconversion at Week 48 (OR 0.292; 95% CI 0.131-0.649; P = 0.003). In conclusion, virological response at Week 12 indicated a great reduction of intrahepatic DNA and cccDNA load in HBeAg-positive CHB patients. The baseline intrahepatic HBV DNA load affected virological response at Week 12 and HBeAg seroconversion at Week 48.

Recording Bessel-like beam shapes generated by plasmonics lens

In our study, we spun a negative photoresist layer on top of a plasmonic lens which was formed by adopting a metallic ring structure with a nano-scale width opening. We recorded the beam shape of the Bessel-like beam emitting from the plasmonic lens which formed a high aspect ratio structure. We found that the high aspect ratio structure was higher after exposure as the inner and outer diameter had increased. In addition, we used an oblique incidence on the negative resist metallic ring structure to produce an inclined micro-structure. Different exposure results were obtained with the two different metal thicknesses. Therefore, in our study, we not only proved that it is possible to record the shape of a Bessel-like beam, but we also demonstrated that it is possible to create a plasmonic lens which is capable of creating a high aspect ratio structure through exposure.

Polymorphisms of short tandem repeat of genes and breast cancer susceptibility

AIM

To explore the relationship of short tandem repeat polymorphisms and breast cancer susceptibility.

METHODS

We searched the MEDLINE database (up to June 2006) with the keywords of tandem repeat sequences, gene polymorphisms, breast cancer, cancer susceptibility and microsatellite instability. We reviewed the literature on gene polymorphisms, especially the relationship of short tandem repeat and breast cancer risk.

RESULTS

We focused on the candidate genes sex hormones, steroid hormone and receptors, carcinogen metabolism, cell proliferation regulation and other genes.

CONCLUSIONS

The functional effects of short tandem repeat polymorphisms on cancer susceptibility, especially on breast cancer risk, are identified. The importance of short tandem repeat polymorphisms on development and progression of breast cancer are discussed.

Homeobox genes and their functions on development and neoplasm in gastrointestinal tract

AIM

To describe the role of homeobox genes on development and tumorigenesis in gastrointestinal tract.

METHODS AND RESULTS

We searched the MEDLINE database (until March, 2006) with the keywords of homeobox genes, gastrointestinal tract, development, tumorigenesis, carcinogenesis and therapeutic targets. We reviewed the literature on classification of homeobox genes, development of gastrointestinal tract, carcinogenesis of gastrointestinal tract as well as therapeutic targets.

CONCLUSIONS

The functional effects of homeobox family in development and tumorigenesis of gastrointestinal tract are identified. The importance of homeobox genes and a possibility of therapeutic intervention in clinical medicine are discussed.

[Effects of antiviral effects of agents and prognosis of chronic hepatitis B.]

BACKGROUND

To analyze the effects of difference antiviral agents and the effects of the treatments on long-term prognosis.

METHODS

Retrospective research method was applied.

RESULTS

About 40% of the patients were treated with interferon or lamivudine. After the treatment, in lamivudine group, the negative rate of HBV DNA was the highest. In the interferon group, the sero conversion rates of HBeAg/HBeAb were 22.9%. In the antiviral treatment patients, the disease progression and the occurrence of cirrhosis and liver cancer were much lower than those of the control groups. The mortality of cirrhosis and liver cancer in the HBeAg/HBeAb sero converted group was much lower than that of the group without HBeAg/HBeAb sero conversion groups (P less than 0.05).

CONCLUSION

The antiviral effects of interferon and lamivudine were better than those of the other drug groups. The antiviral drugs could relieve the disease progression and reduce the mortality of cirrhosis and liver cancer.

NF-κB as a molecular target in adjuvant therapy of gastrointestinal carcinomas

AIM

To describe the role of nuclear factor-kappa B (NF-kappaB) in cancer treatment.

METHODS

We searched the Pubmed database (until Oct, 2004) with the keywords of gastrointestinal carcinoma, NF-kappaB, inhibitor, cancer treatment molecular target and chemoresistance. We reviewed the literature in the role of NF-kappaB activation in chemoresistance, tumour growth suppression and enhancement of apoptosis in gastrointestinal carcinomas.

CONCLUSIONS

Several possible strategies for inhibiting NF-kappaB activation are identified. The importance of targeting NF-kappaB as a potential therapeutic approach in clinical medicine was discussed.

Germline mutational analysis of CDH1 and pathologic features in familial cancer syndrome with diffuse gastric cancer/breast cancer proband in a Chinese family

AIMS

Hereditary non-polyposis colorectal cancer, thyroid medullary carcinoma, breast/ovarian cancer and gastric cancer/breast cancer syndrome are encountered in surgery. Some gastric cancer/breast cancer syndrome may be the result of a CDH1 germline mutation. This is the first report of CDH1 germline mutations gastric cancer/breast cancer syndrome in Chinese patients.

METHODS

Peripheral blood from the proband, as well as, her first and second degree relatives was collected and CDH1 gene exon 1-16 mutations were screened. E-cadherin/beta-catenin proteins expression and histopathologic features were examined on gastric cancer/breast cancer tissues from the proband.

RESULTS

A C-->T nucleotide substitution at exon 13 (mRNA 2200 locus, Accession number NM-004360) was found. This was a transition from GCC-->GCT in DNA sequence (Ala154Ala). Diffuse-type gastric cancer and infiltrating ductal breast carcinoma were present. Both tumours preserved E-cadherin/beta-catenin expression immunohistochemically.

CONCLUSIONS

Familial cancer syndrome with diffuse-type gastric cancer/breast cancer proband in Chinese has a propensity of early onset during lifespan. No truncating or splice-site CDH1 mutations had been identified in this family. A silent nucleotide variation in exon 13 of the CDH1 gene may contribute to some forms of cancer susceptibility.

Chemiluminescence detection for hybridization assays on the flow-thru chip, a three-dimensional microchannel biochip

Chemiluminescence (CL) detection is seldom used in two-dimensional solid support microarray platforms because adequate sensitivity and spatial resolution is difficult to achieve. The three-dimensional ordered microchannels of the Flow-thru Chip increase both the sensitivity and spatial resolution required for quantitative CL measurements on microarrays. Enzyme-catalyzed CL reactions for the detection of hybridizations on microchannel glass were imaged using a CCD camera. Signal uniformity, sensitivity, and dynamic range of the detection method were determined. The relative standard deviation of signal intensities across an array of 64 spots was 8.1%. A detection limit of 250 amol of target with a linear dynamic range of 3 orders of magnitude was obtained for a 3-h assay. Similar to two-color fluorescence measurements, multiple enzyme labels were employed to demonstrate two-channel chemiluminescence. A unique method for measuring the relaxation time of a chemiluminescent species is also described.

Interactions of HLA-B27 with the peptide loading complex as revealed by heavy chain mutations

MHC class I heavy chains assemble in the endoplasmic reticulum with beta(2)-microglobulin and peptide to form heterotrimers. Although full assembly is required for stable class I molecules to be expressed on the cell surface, class I alleles can differ significantly in their rates of, and dependencies on, full assembly. Furthermore, these differences can account for class I allele-specific disparities in antigen presentation to T cells. Recent studies suggest that class I assembly is assisted by an elaborate complex of proteins in the endoplasmic reticulum, collectively referred to as the peptide loading complex. In this report we take a mutagenesis approach to define how HLA-B27 molecules interact with the peptide loading complex. Our results define subtle differences between how B27 mutants interact with tapasin (TPN) and calreticulin (CRT) in comparison to similar mutations in other mouse and human class I molecules. Furthermore, these disparate interactions seen among class I molecules allow us to propose a spatial model by which all class I molecules interact with TPN and CRT, two molecular chaperones implicated in facilitating the binding of high-affinity peptide ligands.

Tapasin enhances peptide-induced expression of H2-M3 molecules, but is not required for the retention of open conformers

H2-M3 is a class Ib MHC molecule that binds a highly restricted pool of peptides, resulting in its intracellular retention under normal conditions. However, addition of exogenous M3 ligands induces its escape from the endoplasmic reticulum (ER) and, ultimately, its expression at the cell surface. These features of M3 make it a powerful and novel model system to study the potentially interrelated functions of the ER-resident class I chaperone tapasin. The functions ascribed to tapasin include: 1) ER retention of peptide-empty class I molecules, 2) TAP stabilization resulting in increased peptide transport, 3) direct facilitation of peptide binding by class I, and 4) peptide editing. We report in this study that M3 is associated with the peptide-loading complex and that incubation of live cells with M3 ligands dramatically decreased this association. Furthermore, high levels of open conformers of M3 were efficiently retained intracellularly in tapasin-deficient cells, and addition of exogenous M3 ligands resulted in substantial surface induction that was enhanced by coexpression of either membrane-bound or soluble tapasin. Thus, in the case of M3, tapasin directly facilitates intracellular peptide binding, but is not required for intracellular retention of open conformers. As an alternative approach to define unique aspects of M3 biosynthesis, M3 was expressed in human cell lines that lack an M3 ortholog, but support expression of murine class Ia molecules. Unexpectedly, peptide-induced surface expression of M3 was observed in only one of two cell lines. These results demonstrate that M3 expression is dependent on a unique factor compared with class Ia molecules.