S-scheme towards interfacial charge transfer between POMs and MOFs for efficient visible-light photocatalytic Cr (VI) reduction.

The establishment of heterojunctions was considered as an exceptional strategy to obtain high-efficiency charge separation and enhanced photocatalytic performance. Herein, a series of FePMo/MIL-53(Fe) (FeM-53) heterojunctions were successfully constructed through in-situ growth of FePMo onto MIL-53(Fe) surface and their photocatalytic capacity were examined by visible-light-induced Cr(VI) reduction. Interestingly, the as-fabricated composites offered various photocatalytic activities controllably relying on the mass ratio of FePMo to MIL-53(Fe). Particularly, the one with the 10% ratio displayed the highest Cr(VI) reduction rate (100%) within 75 min, which was respectively over 4 and 2 folds higher than pure FePMo and MIL-53(Fe). The boosted photoactivity might be ascribed to the establishment of S-scheme heterojunction with suitable band alignment between FePMo and MIL-53(Fe), which broadened the light absorption range and improved charge separation. Further mechanism investigations implied both •O2- and e- were the key reactive species for Cr(VI) removal. Besides, the composite preserved excellent stability after 4 consecutive tests, and performed well in the presence of organic dyes. Such a S-scheme heterojunction may promise for highly efficient environmental mitigation.

Self-assembly of colloids with competing interactions confined in spheres.

At low temperatures, colloidal particles with short-range attractive and long-range repulsive interactions can form various periodic microphases in bulk. In this paper, we investigate the self-assembly behaviour of colloids with competing interactions under spherical confinement by conducting molecular dynamics simulations. We find that the cluster, mixture, cylindrical, perforated lamellar and lamellar structures can be obtained, but the details of the ordered structures are different from those in bulk systems. Interestingly, the system tends to form more perforated structures when confined in smaller spheres. The mechanism behind this phenomenon is driven by the relationship between the energy of the ordered structures and the bending of the confinement wall, which is different from the mechanism in copolymer systems.

[Application of lingual wedge shaped coronectomy in extraction of horizontally impacted mandibular third molars].

PURPOSE: To investigate the effect of lingual wedge shaped coronectomy in extraction of horizontally impacted mandibular third molar(HIMTM). METHODS: A total of 172 patients with HIMTM were randomly divided into experimental group and routine group with 86 cases in each group . Lingual wedge-shaped coronectomy was applied in the experimental group and T-shaped coronectomy was applied in routine group. Operation time, intraoperative and postoperative complications were compared between the two groups.The data were analyzed by using SPSS 26.0 software package. RESULTS: The operation time of the experimental group was significantly shorter than that of the control group (P＜0.05). The rate of swelling, pain, lingual bone plate injury and broken root of the experimental group were separately lower than that of the control group, and the difference was statistically significant(P＜0.05). CONCLUSIONS: Lingual wedge shaped coronectomy of HIMTM has significant advantages in the extraction of HIMTM. It can reduce operation time，broken roots,fracture of lingual plate, postoperative swelling, pain and other surgical complications.

S-scheme MOF-on-MOF heterojunctions for enhanced photo-Fenton Cr(VI) reduction and antibacterial effects.

The photocatalytic efficiency is commonly restrained by inferior charge separation rate. Herein, the S-scheme MIL-100(Fe)/NH2-MIL-125(Ti) (MN) photo-Fenton catalyst with the built-in electric field (BEF) was successfully constructed by a simple ball-milling technique. As a result, the MN-3 (the mass ratio of MIL-100(Fe) to NH2-MIL-125(Ti) was 3) composite presented the best visible-light-induced photocatalytic ability, in contrast to pure MIL-100(Fe) and NH2-MIL-125(Ti). The reduction efficiency of Cr(VI) almost reached 100% within 35 min of illumination. Moreover, the MN-3 heterojunction also exhibited the highest antibacterial activity, and about 100% E. coli and more than 90% S. aureus were killed within 60 min of illumination. In photo-Fenton system, In the photo-Fenton system, e-, O2•- and Fe2+ played vital roles for Cr(VI) reduction, and •OH, h+ and O2•- and 1O2 were responsible for sterilization. Additionally, 5 cyclic tests and relevant characterizations confirmed the excellent repeatability and stability of the composite. Also, the S-scheme charge transfer process was put forward. This work offers a novel idea for establishing the MOF-on-MOF photo-Fenton catalyst for high-efficiency environmental mitigation.

Ferric-ellagate complex: A promising multifunctional photocatalyst.

The semiconductors have exhibited great potential in the field of photocatalytic energy production, environmental remediation and bactericidal. Nevertheless, those inorganic semiconductors are still restricted in commercial application due to the drawbacks of easy agglomeration and low solar energy conversion efficiency. Herein, ellagic acid (EA) based metal-organic complexes (MOCs) were synthesized through a facile stirring process at room temperature with Fe3+, Bi3+ and Ce3+ as the metal center. The EA-Fe photocatalyst exhibited superior photocatalytic activity toward Cr(VI) reduction, where Cr(VI) were completely removed within 20 min. Meanwhile, EA-Fe also displayed good photocatalytic degradation of organic contaminants and photocatalytic bactericidal performance. The photodegradation rates of TC and RhB by EA-Fe were 15 and 5 times that by bare EA, respectively. Moreover, EA-Fe was capable of effectively eliminating both E. coli and S. aureus bacteria. It was found that EA-Fe was capable of generating superoxide radicals, which could participate in the reduction of heavy metals, degradation of organic contaminants and inactivation of bacteria. A photocatalysis-self-Fenton system could be established by EA-Fe solely. This work would provide a new insight for designing multifunctional MOCs with high photocatalytic efficiency.

The Effects of Acid and Water in the Formation of Anodic Alumina: DFT and Experiment Study.

The DFT method is employed to study the adsorption and reaction behaviors of HC2O4-, H2PO4-, HSO4- and H2O on neutral and anodic aluminum slabs. With the exception of adsorption, the three acid radicals can successively take the two H atoms from the adsorbed H2O on the anodic aluminum slabs, which is the key step of the formation of anodic alumina. The dehydrogenation reaction is dominated by the Coulombic interaction of O and H, respectively belonging to acid radicals and the adsorbed H2O or OH, rather than by the interaction of electronic orbits located on the two kinds of atoms. The experiment of anodic polarization of aluminum verifies the calculation result well.

Preparation of novel diperylene-cored polyimide photocatalyst with broad-spectra response and high stability.

A novel polyimide (PI) with broad-spectra response, high photocatalytic activity and stability under super acidic conditions (pH = 0) was synthesized via polymerizing method. Two types of perylene-cored materials (PDIAN and PTCDA) with anhydride and diamine respectively, were applied as precursors for PI polymerization. The as-prepared PI was optimized at 1:1 initial molar ratio of PDIAN to PTCDA. Using common PI (synthesized from melamine and pyromellitic dianhydride) as comparison, the Cr(VI) reduction rate was boosted from 25.4% to 96.6% within 120 min light irradiation. The corresponding rate constant by PI(PDIAN/PTCDA) was estimated to be ca. 11.7 times relative to that by common PI. The boosted performance was ascribed to the strong π-π conjugation from diperylene cores, which can decrease the photoluminescence intensity and electrochemical impedance, so as to promote the separation and transfer of photogenerated electron-hole pairs. In addition, the optimized PI(PDIAN/PTCDA) displayed wide-spectra response, which can still work under 730 nm light. The influencing factors toward Cr(VI) reduction were also clarified to be beneficial at lower pH and increased concentration of hole scavenger. After five cycles at pH 0, the PI still maintained excellent redox activity and structural stability.

Exceptional visible-light photoelectrocatalytic activity of dual Z-scheme Bi@BiOI-Bi2O3/C3N4 heterojunction for simultaneous remediation of Cr(VI) and phenol.

Developing highly efficient and stable photocatalysts remains a major challenge for the remediation of environmental pollutants. In this work, the Bi0 decorated BiOI-Bi2O3/C3N4 heterojunction (Bi@BiOI-Bi2O3/C3N4) film was fabricated through ultrasonic stripping, I- etching and in situ UV-reduction processes and then characterized thoroughly by various analytical techniques. The characteristics of simultaneous mitigation of phenol and Cr(VI) were evaluated over Bi@BiOI-Bi2O3/C3N4 photoanode under visible light. The results exhibited that both phenol and Cr(VI) were removed completely by the photoanode at 2.5 V within 1.5 h, superior to our previous report. The synergy of the surface plasmon resonance (SPR) effect of Bi0 and ternary heterojunction accelerated the separation and transfer of photo-induced charge carrier and thus heavily promoted the removal efficiency. Moreover, the excellent stability of this photoanode was hold with no considerably activity attenuation after 4 cycles. Finally, a dual Z-scheme charge transfer process was presented. This work offers an attractive pathway to construct highly active photoelectrode with promising application for simultaneous remediation of organics and heavy metals in wastewater.

PDINH bridged NH2-UiO-66(Zr) Z-scheme heterojunction for promoted photocatalytic Cr(VI) reduction and antibacterial activity.

Z-scheme mechanism was a promising approach to considerably enhance photocatalytic activity. In this work, the PDINH/NH2-UiO-66(Zr) (PNU) heterojunctions were made using a facile ball-milling method. As expect, the optimum PNU-1 composite acted as highly active photocatalyst with 97% Cr(VI) to be reduced within 60 min of LED light illumination. Moreover, the antibacterial rate almost reached 100% for E. coli and S. aureus in 4 h, which was more conspicuous than the others. The wider light absorption range, promoted charge separation because of Z-scheme mechanism and efficient generation of reactive 1O2, •O2-, and •OH contributed greatly to the enhanced photocatalytic activity. Meanwhile, the superior stability and repeatability of the composites were also demonstrated by five cyclic experiments and related physicochemical characterizations. Therefore, this work provides a novel insight for designing high-efficiency Z-scheme heterostructures between MOFs and organic PDINH for wastewater remediation.

Comparison of four methods that remove calcium hydroxide from root canals / 口腔疾病防治

Objective@# To compare the efficiency of four methods that remove calcium hydroxide in root canals and to guide clinical practice. @* Methods @# Sixty-five isolated mandibular single root canal premolars were collected. After crown cutting and root canal preparation, a tooth was randomly selected as the blank control group, and the remaining 64 teeth were equally divided into Groups A and B (n = 32). Group A was injected with water-soluble calcium hydroxide, and Group B was injected with oil-soluble calcium hydroxide. After 2 weeks of drug sealing, Groups A and B were randomly divided into 4 groups (n = 8), including the lateral opening syringe group, sonic vibration group, ultrasonic group, and Er: YAG laser group. Before and after calcium hydroxide removal, the samples were scanned by cone-beam CT, and the data were imported into Mimics for 3D reconstruction. The root canal was divided into the following segments: superior root segment, middle and apical, and the calcium hydroxide volume of each segment of the root canal was calculated. The volumes of calcium hydroxide before and after removal were V1 and V2, respectively, with a clearance rate = (V1-V2)/V1×100%. Three-factor ANOVA was used for statistical analysis. After Groups A and B were reconstructed, the apical region with residual calcium hydroxide was selected, and the blank control was observed by scanning electron microscopy (SEM). @*Results @# Two types of calcium hydroxide could not be completely removed by the four flushing methods. The clearance rate of water-soluble calcium hydroxide was higher than that of oil-soluble calcium hydroxide (P<0.001). Among the three segments of the root canal, the clearance rate of the apical segment was lower (P<0.05). The Er: YAG laser treatment group showed the highest removal efficiency of two kinds of calcium hydroxide, which was higher than that of the other groups, especially in apical of the root. Compared with the sonic wave washing group and the syringe washing group, the ultrasonic wave washing group exhibited significant advantages (P<0.05). The clearance rate of the sonic wave washing group was higher in the oily calcium hydroxide root middle group than in the syringe washing group (P<0.05). SEM showed that the two kinds of calcium hydroxide could not be completely removed, but the residual rate of oil-soluble calcium hydroxide was large.@*Conclusion @# Both types of calcium hydroxide could not be completely removed, and compared to water-soluble calcium hydroxide, oil-soluble calcium hydroxide was more difficult to remove. Among the four cleaning methods, Er:YAG laser swing washing showed the higher cleaning efficiency.

Case report: Condylar metastasis from hepatocellular carcinoma: An uncommon case report and literature review.

Background: Patients with hepatocellular carcinoma are often affected by metastases, but condylar metastasis is particularly rare. Case presentation: A 51-year-old man with a history of hepatocellular carcinoma requested treatment for facial pain. Computed tomography indicated that the condylar bone has been destroyed and fractured. Pathology confirmed condylar metastasis from hepatocellular carcinoma. Complete metastasectomy and condylar reconstruction were performed to preserve his facial appearance. No local recurrence or distant metastasis was found at 8 months of follow-up. Conclusion: The condyle can be a metastatic site of hepatocellular carcinoma, regardless of its rarity. Long-term comprehensive surveillance and follow-up are needed for patients with hepatocellular carcinoma. The presence of solitary mass does exclude the possibility of metastatic cancer for these patients, and postoperative imaging and pathological diagnosis are important to determine its origin. If patients' physical condition permits, the mass can be completely excised, and the physiological function can be restored and reconstructed.

Integrated Analysis of lncRNA-Associated ceRNA Network Identifies Two lncRNA Signatures as a Prognostic Biomarker in Gastric Cancer.

BACKGROUND: Gastric cancer (GC) is a malignant tumour that originates in the gastric mucosal epithelium and is associated with high mortality rates worldwide. Long noncoding RNAs (lncRNAs) have been identified to play an important role in the development of various tumours, including GC. Yet, lncRNA biomarkers in a competing endogenous RNA network (ceRNA network) that are used to predict survival prognosis remain lacking. The aim of this study was to construct a ceRNA network and identify the lncRNA signature as prognostic factors for survival prediction. METHODS: The lncRNAs with overall survival significance were used to construct the ceRNA network. Function enrichment, protein-protein interaction, and cluster analysis were performed for dysregulated mRNAs. Multivariate Cox proportional hazards regression was performed to screen the potential prognostic lncRNAs. RT-qPCR was used to measure the relative expression levels of lncRNAs in cell lines. CCK8 assay was used to assess the proliferation of GC cells transfected with sh-lncRNAs. RESULTS: Differentially expressed genes were identified including 585 lncRNAs, 144 miRNAs, and 2794 mRNAs. The ceRNA network was constructed using 35 DElncRNAs associated with overall survival of GC patients. Functional analysis revealed that these dysregulated mRNAs were enriched in cancer-related pathways, including TGF-beta, Rap 1, calcium, and the cGMP-PKG signalling pathway. A multivariate Cox regression analysis and cumulative risk score suggested that two of those lncRNAs (LINC01644 and LINC01697) had significant prognostic value. Furthermore, the results indicate that LINC01644 and LINC01697 were upregulated in GC cells. Knockdown of LINC01644 or LINC01697 suppressed the proliferation of GC cells. CONCLUSIONS: The authors identified 2-lncRNA signature in ceRNA regulatory network as prognostic biomarkers for the prediction of GC patient survival and revealed that silencing LINC01644 or LINC01697 inhibited the proliferation of GC cells.

[Effects of dynamic nutrition support on energy metabolism, immune function and stress response after oral and maxillofacial tumor surgery].

PURPOSE: To observe the effect of dynamic nutrition support on postoperative energy metabolism, immune function and stress response in patients with oral and maxillofacial tumors. METHODS: Fifty-six patients with oral and maxillofacial tumor surgery were randomly divided into experimental group and control group (28 in each group). Patients in the experimental group received dynamic enteral and parenteral nutrition support according to the stress period after surgery, ω-3 fish oil fat milk injection and glutamine were added in the nutrition support program. Patients in the control group were given routine postoperative enteral and parenteral camp support. Energy metabolism, immune function and stress indexes were detected 1 day before surgery, 2 days after surgery and 7 days after surgery, respectively. SPSS 19.0 software package was used to analyze the data. RESULTS: Energy metabolism indexes in the experimental group were higher than the control group on day 2 after PA surgery and day 7 after ALB and PA surgery, while energy metabolism indexes in the experimental group were lower than the control group on day 2 and day 7 after FPG and TG surgery with significant difference(P<0.05). The levels of IgA, IgG, IgM, CD3+, CD4+ and CD4+/CD8+ in the experimental group were higher than those in the control group 7 days after surgery, with significant differences (P<0.05). The levels of CRP, TNF- and IL-6 in the experimental group were lower than those in the control group 7 days after surgery, and the difference was significant(P<0.05). There was no significant difference in postoperative complications between the two groups. CONCLUSIONS: Dynamic nutrition support can improve postoperative energy metabolism of patients with oral and maxillofacial tumors, improve immune function, and alleviate stress response.

Cell sheet-engineered bones used for the reconstruction of mandibular defects in an animal model.

The aim of the present study was to investigate the generation of cell sheet-engineered bones used for the reconstruction of mandibular defects. Bone marrow stem cells (BMSCs) were cultured and induced to generate osteoblasts. Poly(lactic-co-glycolic acid) (PLGA) scaffolds were wrapped with or without cell sheets and then implanted into dogs with mandibular defects in the right side (experimental group) or the left side (control group), respectively. Subsequently, X-ray analyses, and hematoxylin and eosin staining were performed at various time points (at 4, 8, 12 or 16 weeks post-implantation; n=4 at each time point). The osteogenesis in the experimental group was significantly improved compared with that in the control group. At 16 weeks after implantation, numerous Haversian systems and a few lamellar bones were observed at the periphery. In the control group, the engineered bone (without BMSC sheets) presented fewer Haversian systems and no lamellar bones. The optical density of the fresh bone in the experimental group was significantly higher compared with that in the control group (P<0.05). In conclusion, tissue-engineered bone with the structure of lamellar bones can be generated using BMSC sheets and implantation of these bones had an improved effects compared with the control group. Cell sheet transplantation was found to enhance bone formation at the reconstruction site of the mandibular defects.

Mechanical analysis on individualized finite element of temporal-mandibular joint under overlarge jaw opening status.

BACKGROUND: Analyze the stress status of temporal-mandibular joint (TMJ) of a healthy volunteer under the overlarge jaw opening status through the finite element method, with the purpose of clarifying the loading features of each structure in the joint area, and achieving further understanding of the pathogenesis of the temporomandibular disorders (TMD). METHODS: Collect the CBCT and MRI data of a volunteer respectively under the maximum jaw opening, establish the finite element model (FEM) of TMJ under the maximum jaw opening status through a series of software, image segmentation, rectification, meshing, material evaluation and other related processing, simulate the mechanical environment of this joint area under this status, and analyze the stress status of the articular disc, condyle cartilage, and condyle process. RESULTS: Based on CT and MRI image data, build 3D model and FEM of TMJ, fully simulate the mechanical environment under the large jaw opening status, and calculate the stress value of the articular disc, condyle process and condylar cartilage. CONCLUSIONS: This research result reminds us that the normal people's articular disc are easy to generate stress concentration under large jaw opening, but its stress is far less than the one under the tight biting status. Perhaps the TMJ symptom induced under the large jaw opening status is mainly caused by the displacement of the articular disc. Under the large jaw opening status, the condylar cartilage plays a vital role in dispersing the stress. This method can be applied for carrying out individualized mechanical analysis on the patients with TMD.

Mandibular metastasis as an initial manifestation of hepatocellular carcinoma: A report of two cases.

The present study reports two cases of mandibular metastasis from hepatocellular carcinoma (HCC), including the clinical presentation, and computed tomography (CT), histopathology and immunohistochemistry results. Space-occupying lesions occurred unilaterally as an initial mandibular manifestation. HCC metastasis was confirmed by post-surgical examination, and the primary tumor was found using CT scans. Hepatitis B virus infection history and positive results of hepatitis B surface antigen, hepatitis B e-antibody, hepatitis B core antibody and hepatitis B virus pre-S1 antigen further supported the pathogenesis of HCC. Based on the clinical findings, the characteristics of the CT scans and the histopathology and immunohistochemistry results, the mechanisms of HCC metastasis and its management are also discussed.

Construction of functional tissue-engineered bone using cell sheet technology in a canine model.

The aim of the present study was to construct functional tissue-engineered bone with cell sheet technology and compare the efficacy of this method with that of traditional bone tissue engineering techniques. Canine bone mesenchymal stem cells (BMSCs) were isolated using density gradient centrifugation and then cultured. The BMSCs were induced to differentiate into osteoblasts and cultured in temperature-responsive culture dishes. The BMSCs detached automatically from the temperature-responsive culture dishes when the temperature was reduced to 20°C, forming an intact cell sheet. Demineralized bone matrix (DBM) and platelet-rich plasma (PRP) were prepared and used to construct a DBM/PRP/BMSC cell sheet/BMSC complex, which was implanted under the left latissimus dorsi muscle in a dog model. A DBM/PRP/BMSC complex was used as a control and implanted under the right latissimus dorsi muscle in the dog model. Immunoblot assays were performed to detect the levels of growth factors. Osteogenesis was observed to be induced significantly more effectively in the DBM/PRP/BMSC cell sheet/BMSC implants than in the DBM/PRP/BMSC implants. Immunoblot assay results indicated that the levels of the growth factors platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) in the experimental group were 3.2- and 2.5-fold higher compared with those in the control group, respectively. These results indicated that the BMSC cell sheets were functional and more effective than the control cell complex. Therefore, cell sheet technology may be used for the effective construction of functional tissue-engineered bone with ideal properties.

A preliminary study on the application of bone marrow stromal cell sheet on the formation of functional tissue-engineered bone in dogs.

PURPOSE: The aim of this study was to construct functional tissue-engineered bone in dogs using cell sheet engineering, a new technique to gain and transfer seed cells. MATERIALS AND METHODS: Demineralized bone matrixes, prepared from homologous bone, were coated with recombinant human bone morphogenetic protein-2. Bone marrow stromal cells (BMSCs) were isolated and subcultured. Osteogenic-induced BMSCs were incubated in a temperature-responsive culture dish to form the BMSC sheet. The complex of demineralized bone matrix, recombinant human bone morphogenetic protein-2, and BMSCs wrapped with BMSC sheets was implanted around the blood vessels of the latissimus dorsi muscle in the experimental side, and the same complex without BMSC sheets was implanted around the blood vessels of the latissimus dorsi muscle on the other side as a control. At 4, 8, 12, and 16 weeks after implantation, the implants were removed for radiographic evaluation, descriptive histologic observation, and histologic quantitative analysis. RESULTS: Radiographic analysis showed that the optical density of the tissue-engineered bone on the 2 sides increased with time. However, the optical density of the experimental side was significantly greater than that of the control side at the same points. Sixteen weeks after implantation, mature lamellar bone was formed in the experimental side, with red bone marrow in the bone marrow cavity. In contrast, the control side exhibited significantly less lamellar bone. Histologic quantitative analysis showed that the experimental side exhibited significantly more bone per area compared with the control side. CONCLUSION: BMSC sheet engineering may be useful to construct functional tissue-engineered bone.

Single nucleotide polymorphisms in the u-PA gene are related to susceptibility to oral tongue squamous cell carcinoma in the Northern Chinese Han population.

AIM: The purpose of this study was to determine whether susceptibility to oral tongue squamous cell carcinoma (OSCC) is related to polymorphisms in the u-PA gene. METHODS: We examined the rs2227564 C/T and rs2227562 G/A single nucleotide polymorphisms (SNPs) in 196 OSCC patients and 201 age- and gender- matched controls via direct sequencing and PCR-RFLP methods. RESULTS: Significant differences were found in allelic and genotypic distributions of the rs2227564 and rs2227562 loci when comparing cases and controls. In addition, logistic analyses indicated that the rs2227564 C/T genotype was related to a 1.52-fold increased risk of developing OSCC (adjusted OR=1.521, 95%CI: 1.144~2.022, P=0.004). Linkage disequilibrium analysis was conducted and no association between the two loci was found (D'=0.031, r2=0.000). CONCLUSIONS: Our findings provide evidence that the rs2227564 C/T SNP in the u-PA gene is associated with the development of OSCC.

A dominant CD4(+) T-cell response to Helicobacter pylori reduces risk for gastric disease in humans.

BACKGROUND & AIMS: Immunodominance is an important feature of antiviral, antitumor, and antibacterial cellular immune responses, but it is not well demonstrated in the immune responses against Helicobacter pylori. Antigen-specific CD4(+) T cells protect mice against infection with H pylori. We investigated the immunodominant CD4(+) T-cell response to neuraminyllactose-binding hemagglutinin (HpaA), which is a conserved, H pylori-specific colonization factor that is being investigated as an antigen for vaccination strategies. METHODS: HpaA-specific CD4(+) T cells were expanded with autologous peripheral blood mononuclear cells that had been incubated with recombinant HpaA and characterized using overlapping synthetic peptides. We compared the percentage of CD4(+) T cells with specificity for HpaA(88-100), restricted to HLA-DRB1*1501, among 59 H pylori-infected subjects with different gastric diseases. RESULTS: We identified and characterized several immunodominant CD4(+) T-cell epitopes derived from HpaA. The immunodominant CD4(+) T-cell responses specific to HpaA(88-100) were observed in most H pylori-infected individuals who expressed HLA-DRB1*1501 and were significantly more abundant in patients with less severe diseases (P < .05). CONCLUSIONS: The HLA-DRB1*1501-restricted immunodominant CD4(+) T-cell response to HpaA(88-100) is associated with reduced risk of severe gastric diseases. Further study of these and other immunodominant CD4(+) T-cell responses to H pylori will provide insight into mechanisms of protective immunity and aid in vaccine design.