BACKGROUND:The biomechanical effect of the implant-bone interface is one of the most important factors for bone resorption. The new structure of the periodontal-ligament-like implants may improve the distribution of the interfacial stress. OBJECTIVE:To discuss the effect of the internal structure changes of traditional implants on the cortical bone stress distribution and peak at the implant-bone interface under different occlusal load conditions, so as to provide a theoretical basis for the optimization design and clinical application of new structure implants. METHODS:Two kinds of digital models, new structure implant (model A) and non-threaded cylindrical implant (model B), were established by Pro/ENGINEER software. Variations of the stress peak and stress distribution of implant-bone interface cortical bone area under the same bone and force environment were analyzed using Ansys software. RESULTS AND CONCLUSION: Under a vertical loading, the stress peak under different forces was reduced by 17.54% in model A compared with model B; under a 45° loading, the stress peak of model A was reduced by 2.59% compared with model B, and it showed an evident tendency of high stress area focusing to the buccal side of model B. Under the chew-simulation loading, the stress peak of model A was lower than that of model B. The biggest difference (0.353 2 MPa) appeared atβ=12°(β is the angle of force direction and the implant axis), and it gradualy reduced atβ > 12°. At the same time, model A had a wider range of application degree compared with model B in two quantitative indicators, including optimal peak stress of promoting bone tissue growth and stress peak of maintaining healthy bone tissue. These results suggest that the optimized structure of implants contributes to improve the cortical bone stress distribution at the implant-bone interface, decrease the peak stress, and reduce the risk of cortical bone absorption in a wider range.

Objective:To construct human adipose-derived mesenchymal stem cells (hASCs)-biomate-rial mixture 3D bio-printing body and detect its osteogenesis in vivo,and to establish a guideline of osteogenesis in vivo by use of 3D bio-printing technology preliminarily.Methods:P4 hASCs were used as seed cells,whose osteogenic potential in vitro was tested by alkaline phosphatase (ALP)staining and alizarin red staining after 1 4 d of osteogenic induction.The cells were added into 20 g/L sodium alginate and 80 g/L gelatin mixture (cell density was 1 ×1 06/mL),and the cell-sodium alginate-gelatin mixture was printed by Bioplotter 3D bio-printer (Envision company,Germany),in which the cells’survival rate was detected by live-dead cell double fluorescence staining.Next,the printing body was osteogeni-cally induced for 1 week to gain the experimental group;and the sodium alginate-gelatin mixture without cells was also printed to gain the control group.Both the experimental group and the control group were implanted into the back of the nude mice.After 6 weeks of implantation,the samples were collected,HE staining,Masson staining,immunohistochemical staining and Inveon Micro CT test were preformed to analyze their osteogenic capability.Results:The cells’survival rate was 89%±2% after printing.Six weeks after implantation,the samples of the control group were mostly degraded,whose shape was irregu-lar and gel-like;the samples of the experimental group kept their original size and their texture was tough.HE staining and Masson staining showed that the bone-like tissue and vessel in-growth could be observed in the experimental group 6 weeks after implantation,immunohistochemical staining showed that the result of osteocalcin was positive,and Micro CT results showed that samples of the experimental group had a higher density and the new bone volume was 1 8%±1%.Conclusion:hASCs-biomaterial mixture 3D bio-printing body has capability of ectopic bone formation in nude mice,and it is feasible to apply cells-biomaterial mixture 3D bio-printing technology in the area of bone formation in vivo.

Objective To explore the value of diffusion tensor imaging (DTI) and diffusion tensor tracography (DTT) in assessment of Corticospinal tract (CST) and medial lemniscus (ML) in tumors involving brainstem.Methods A total of 35 cases with pathologically confirmed tumors involving brainstem were collected,and 35 volunteers matched with genders and ages were recruited as the normal group.DTI scanning was performed on all the patients and controls.The damage degrees of CST and ML were evaluated and graded by DTT,and the dysfunction degrees were evaluated for the patients.Spearman correlation was used to statistically analyze the relationships of limb movement,sensory dysfunction and CST and ML damage.Results According to the rating results,normal findings,shifting,edema or infiltration and damage of CST was found in 9,9,11,and 6 cases respectively.They were 8,9,15,3 cases for ML.Motor function was normal in 20 cases,slightly defective in 11 cases,and moderate defective in 4 cases.Sensory function was normal in 21 cases,slightly defective in 6 cases,and moderate defective in 8 cases.The patients' dyskinesia and CST damage degree,sensory dysfunction and ML damage degree were positively correlated (r was 0.786 and 0.686 respectively,P ＜ 0.01).The position relationship among tumor and CST and ML could be well displayed on images.None of the patients showed new symptoms of dysneuria after surgery.Conclusions DTI and DTT technology can be used to evaluate CST and ML damage degree in tumors involving brainstem.They can display the position relationship between tumor and the brainstem CST and ML,which is important in protecting the brainstem fiber tract during operation and evaluating the recovery after the operation.

Dental implant restoration has become the preferred clinical option for the treatment of tooth loss. The basis for the functioning of implant prostheses is good osseointegration of the implant. Osteointegration is a delicate and complex biological process that is not only a simple physical attachment but also initiates and regulates a series of important events such as cell survival, migration, recruitment, and osteogenic differentiation, involving a series of physicochemical changes from the molecular to the cellular level. In-depth studies on osseointegration can facilitate the development of new implants, improve the success rate of implantation in complex clinical conditions, and have important implications for the prevention and treatment of peri-implant diseases. In this review, the research on the regulation of cell signal pathways of implant osseointegration was reviewed, including the biological process of implant osseointegration, integrin-mediated signal pathways, Wnt signal pathways, transforming growth factor-β (TGF-β)/bone morphogenetic protein (BMP) signal pathways, hypoxia-inducible factors (HIFs) signal pathways, Notch signal pathways, Hippo signal pathways, and other signal pathways related to bone integration that are expected to provide some theoretical reference for the optimization of implant performance.

Objective:To explore the achievements of clinical teaching and scientific research acquired by visiting scholars funded by medical foundation, which will be benefit for the improvement for cultivation of innovative talents in general hospitals.Methods:Questionnaire data of 132 visiting scholars supported by Beijing Li Huanying Medical Foundation from 2010 to 2016 were analyzed and applied by descriptive statistics.Results:Study abroad has played a positive role in promoting clinical skills, teaching level, and scientific research capacity building. Visitors have significantly improved their teaching titles, mentor positions, paper publishing and approved funding projects, in which there was a year-on-year growth trend high level projects funded.Conclusions:Study abroad is conducive to stimulating the enthusiasm and creativity of medical talents, and also an effective way to enhance the overall strength of the hospital. The foundation exerts the overall planning and leadership role of talent construction, and provides full-chain service and management for overseas study personnel, which is the key to maximize the teaching and research output of medical personnel.

OBJECTIVETo delineate serological features and genetic basis for a rare p phenotype of P1Pk blood group system found in a Chinese individual.

METHODSSerological assaying was carried out for a proband with unexpected antibody found in his serum using specific antibodies and panel cells. Coding regions and flanking introns of α 1,4-galactosyltransferase gene (A4GALT) associated with the p phenotype were screened with polymerase chain reaction and DNA sequencing.

RESULTSA rare p phenotype of the P1Pk blood group system has been identified with red blood cells from the proband, whose serum contained anti-Tja antibody which can agglutinate and hemolyze with other common red blood cells. Other members of the proband's family were all normal with P1 or P2 phenotype. DNA sequencing has identified in the proband a homozygous 26 bp deletion at position 972 to 997 of the A4GALT gene. The deletion has caused a shift of the reading frame, resulting in a variant polypeptide chain with additional 83 amino acid residues compared with the wild-type protein. Other family members were either heterozygous for above deletion or non-deleted.

CONCLUSIONA 26 bp deletion at position 972 to 997 of the A4GALT gene has been identified in a Chinese individual with p phenotype.

ABO Blood-Group System ; genetics ; Alleles ; Base Sequence ; Galactosyltransferases ; genetics ; Genetic Association Studies ; Genotype ; Humans ; Male ; Molecular Sequence Data ; Pedigree ; Phenotype ; Sequence Deletion

Therapeutic drug monitoring(TDM)has played an important role in clinical medicine for precise dosing.Currently,chromatographic technology and immunoassay detection are widely used in TDM and have met most of the needs of clinical drug therapy.However,some problems still exist in practical appli-cations,such as complicated operation and the influence of endogenous substances.Surface plasmon resonance(SPR)has been applied to detect the concentrations of small molecules,including pesticide residues in crops and antibiotics in milk,which indicates its potential for in vivo drug detection.In this study,a new SPR-based biosensor for detecting chloramphenicol(CAP)in blood samples was developed and validated using methodological verification,including precision,accuracy,matrix effect,and extraction recovery rate,and compared with the classic ultra-performance liquid chromatography-ultraviolet(UPLC-UV)method.The detection range of SPR was 0.1-50 ng/mL and the limit of detec-tion was 0.099±0.023 ng/mL,which was lower than that of UPLC-UV.The intra-day and inter-day ac-curacies of SPR were 98％-114％and 110％-122％,which met the analysis requirement.The results show that the SPR biosensor is identical to UPLC-UV in the detection of CAP in rat blood samples;moreover,the SPR biosensor has better sensitivity.Therefore,the present study shows that SPR technology can be used for the detection of small molecules in the blood samples and has the potential to become a method for therapeutic drug monitoring.

Astragali Radix(AR)is a clinically used herbal medicine with multiple immunomodulatory activities that can strengthen the activity and cytotoxicity of natural killer(NK)cells.However,owing to the complexity of its composition,the specific active ingredients in AR that act on NK cells are not clear yet.Cell membrane chromatography(CMC)is mainly used to screen the active ingredients in a complex system of herbal medicines.In this study,a new comprehensive two-dimensional(2D)NK-92MI CMC/C18 column/time-of-flight mass spectrometry(TOFMS)system was established to screen for potential NK cell acti-vators.To obtain a higher column efficiency,3-mercaptopropyltrimethoxysilane-modified silica was synthesized to prepare the NK-92MI CMC column.In total,nine components in AR were screened from this system,which could be washed out from the NK-92MI/CMC column after 10 min,and they showed good affinity for NK-92MI/CMC column.Two representative active compounds of AR,isoastragaloside Ⅰ and astragaloside Ⅳ,promoted the killing effect of NK cells on K562 cells in a dose-dependent manner.It can thus suggest that isoastragaloside Ⅰ and astragaloside Ⅳ are the main immunomodulatory compo-nents of AR.This comprehensive 2D NK-92MI CMC analytical system is a practical method for screening immune cell activators from other herbal medicines with immunomodulatory effects.

OBJECTIVETo investigate the value of serum IgA/C3 ratio in the diagnosis of IgA nephropathy and explore its relationship with the clinicopathological features of the patients.

METHODSSixty-six patients with IgA nephropathy, 111 with other glomerular diseases, and 40 healthy control subjects without kidney disease were tested for serum IgA and C3 levels using CRM470 adjusted standardized immune turbidimetric method, and the IgA/C3 ratio was calculated. According to Oxford and Lee's classification criteria, we analyzed the pathological grades of the renal biopsy samples from patients with IgA nephropathy. The ROC curve was used to assess the value of serum IgA and IgA/C3 ratio in predicting IgA nephropathy.

RESULTSPatients with IgA nephropathy had an elevated serum IgA/C3 ratio than those with other glomerular diseases and the control subjects, with an area under the ROC curve of 0.776. An elevated serum IgA/C3 ratio was not found to significantly correlate with the pathological grade of renal biopsy samples in patients with IgA nephropathy.

CONCLUSIONIn the absence of renal biopsy findings, serum IgA/C3 ratio can help in the diagnosis of IgA nephropathy.

Biopsy ; Case-Control Studies ; Complement C3 ; analysis ; Glomerulonephritis, IGA ; blood ; diagnosis ; Humans ; Immunoglobulin A ; blood ; Kidney ; pathology

Blotting, Western ; Cell Cycle Checkpoints ; Cell Line, Tumor ; Chaperonin 60 ; metabolism ; HEK293 Cells ; Humans ; Mitochondria ; metabolism ; Reactive Oxygen Species ; metabolism ; Real-Time Polymerase Chain Reaction ; Sirtuin 3 ; genetics ; metabolism