BACKGROUND: In clinical practice, the selection of dental implants with different specifications is based on the patient' s mandibular plane angle, and the long-term success rate is different in dental implants with different specifications. Therefore, it is reasonable to assume that the mandibular plane angle could affect the mandibular stress distribution of dental implants, thus affecting the success rate of dental implantation.OBJECTIVE: To perform an orthogonal experimental study on the mechanical effects of different implant specifications, mandibular plane angles and mandibular bone densities on stress distribution of the first mandibular molar implants.METHODS: A L9(33) orthogonal experiment was designed with 3 three-level factors, including mandibular plane angle (14°, 22°, 34°), implant diameter (6.6, 8.2, 9.6 mm), and mandibular bone density (types II, III, IV). Different dental implants with different combinations were implanted into an alveolar bone model, and placed onto a pressure testing machine under 500 N load. Then, strain (stress) data were collected in real-time and analyzed.RESULTS AND CONCLUSION: The optimal combination was as follows: low angle; 4.8 mm in diameter; mandibular bone with type II bone density. The relations of all the three factors were the diameter of dental implant > the mandibular plane angle > mandibular bone density. To conclude, the mandibular plane angle has some certain influences on the stability of dental implants. If the biting force is the same, dental implant bears the largest stress under the high angle,subsequently followed by the average angle and the low angle.

Objective To observe the effect of polyethylene terephthalates (PET) coated with 58S bioactive glass on graft-bone healing.Methods The PET coated with 58S bioactive glass was used in experimental group,and uncoated PET was used as a control.The coating solution was made of 20％ bioactive glass powder and 80％ gelatin powder (by weight).In our vitro study,4×104/ml MT3T3-E1 cells were cultured in 24-well plates with the coated or uncoated PET,and the MTT and ALP were tested at 1,3,5 days to show the proliferation and the activity of the cells.The SEM and the X-ray photoelectron spectrometer were adopted to analyze the surface characteristics of the fiber.In our vivo study,24 skeletally mature New Zealand white rabbits were randomly divided into two groups,the 58S-PET group and the PET group.Both groups underwent a surgical procedure to establish a tibia-articular tendon-bone healing model.Mechanical examination and histological assay were taken to verify the coating effect in vivo.Results The 58S-PET group showed significantly differences in both the MTT and ALP tests at each time point (3,5 days) compared with the PET group.In the animal experiments,the maximum load increased by time in both groups.At 6 weeks,the load-to-failure was significantly higher in the 58S-PET group [(61.70±6.95) N]than that of the PET group [(45.21±9.78) N].At 12 weeks,the load-to-failure was also significantly higher in the 58S-PET group [(89.25±9.50) N]than that of the PET group [(71.38±6.26) N].In the histological assay,it was found that there was new bone formation in the indistinct interface between the graft and the host bone in both groups at 6,12 weeks,and a stronger binding was seen in the 58S-PET group than in the PET group.Conclusion The 58S-PET could enhance the proliferation and activity of the osteoblast and therefore promote the new bone formation and subsequently leads to a positive effect on tendon-bone healing.

BACKGROUND:Recent research has shown that the proper concentration of aspirin can increase the proliferation and osteogenic ability of MG-63 cells.OBJECTIVE:To explore the effects of different concentrations of aspirin on osteoblast proliferation on the implant-cell interface under fluid shear stress.METHODS:(1) MG-63 cells were cultured in low-glucose DMEM containing 10％ fetal bovine serum and different concentrations of aspirin (0,0.023,0.046,0.0625,0.125,0.25,0.5,1.0,2.0,4.0 mmol/L) for 1-7 days.Then cell proliferation was detected using MTS method.(2) MG-63 cells were cultured on three different surfaces:glass slide,PT titanium surface and SLA titanium surface.After 3 days of culture with aspirin at a concentration of 0 or 0.5 mmol/L,the cells were subjected to fluid shear stress.MTS test was applied to estimate the proliferation of MG-63 cells at 0,0.5,1,2,4 hours after stress application.RESULTS AND CONCLUSION:(1) After 1-3 days of culture,0.023,0.046,0.5 mmol/L aspirin promoted the proliferation of MG-63 cells,while after 1-7 days of culture,1,2,4 mmol/L aspirin inhibited the proliferation of MG-63 cells.(2) Under the fluid shear stress,aspirin showed significant effects on the cell proliferation as confirmed by one-way analysis of variance (F=8.349,P=0.004),and 0.5 mmol/L aspirin inhibited the cellular proliferation of MG-63 cells.However,surface modification and stress loading time showed no significant effects on the cell proliferation (F=2.826,P=0.064;F=0.893,P=0.406).(3) Under the fluid shear stress,surface modification showed no significant effect on the cell proliferation of MG-63 cells cultured with 0.5 mmol/L aspirin (F=1.803,P=-0.171).Under the fluid shear stress,0.5 mmol/L aspirin significantly inhibited the proliferation of MG-63 cells on the glass slide (P=-0.003),while PT and SLA titanium surfaces showed on inhibitory effect on the cell proliferation (P=0.891,P=0.051).The present results demonstrate that the cell proliferation of MG-63 is related with aspirin in a concentration-dependent manner.In addition,different titanium surfaces may decrease the sensitivity of MG-63 cell proliferation to aspirin.

Objective:To evaluate the quality of the current foreign clinical practice guidelines (CPG) on obstetric venous thromboembolism (VTE), providing reference for standardizing the prevention and treatment of domestic VTE clinical practice.Methods:The GPGs for the management of obstetric VTE published abroad from inception to July 2020 were electronically searched. Two researchers independently evaluated the quality of the included guidelines in accordance with the internationally recognized guideline evaluation tool, AGREE Ⅱ.Results:A total of 12 guidelines, 2 recommendations and 1 consensus for obstetric VTE were included, covering 3 continents and 9 countries, and the published time span was 2009-2020. The standardized scores of the six domain (scope & purpose, stakeholder involvement, rigor of development, clarity of presentation, applicability and editorial independence) included in the guidelines were: 99.44%, 62.78%, 70.35%, 95.74%, 68.80% and 76.94% respectively, and the scores in each domain were ≥ 50.00%, indicating that the included CPGs were of good quality. Except for the domain scope & purpose, the ranges of the other five domains were ≥ 50.00%, suggesting that the quality of the CPGs differed significantly. Among the 15 included CPGs, 4 CPGs were level A (recommended), 11 CPGs were level B (recommended after being revised), and there was no CPG in level C (not recommended). The difference in the recommended content of obstetric VTE management mainly focused on the risk assessment, drug type, dosage and period.Conclusions:The overall quality of the CPGs for obstetric VTE management is high, while the quality of the CPGs varies greatly. In addition, there are differences in the recommended content of obstetric VTE management. More high-quality researches are required to provide evidence-based support for the improvement of the CPGs.

OBJECTIVETo clone and construct a eukaryotic expression vector of human bone morphogenetic protein (BMP) 2 and histidine in vitro and synthesize chitosan (CS)/pIRES2-EGFP-hBMP2-His nanoparticles.

METHODSpMD18T-hBMP2-His was digested by EcoR I and BamH I to obtain the hBMP2-His gene, which was inserted into pIRES2-EGFP to form pIRES2-EGFP-hBMP2-His. Afterward, CS, which exhibited five different molecular weights and deacetylation degrees, was complexed with pIRES2-EGFP-hBMP2-His to form CS/pIRES2-EGFP-hBMP2-His nanoparticles; in this procedure, a desolvent method was used at different N/P ratios (amino in CS to phospho in plasmid DNA). The gene-encapsulating ability of CS was evaluated by agarose gel electrophoresis and fluorescence spectrophotometry; size, distribution, and potential were analyzed using a ZetaPALS analyzer. The shape of the nanoparticles was observed under an atomic force microscope.

RESULTS1) pIRES2-EGFP-hBMP2-His was constructed after the cloned hBMP2-His gene was confirmed by sequencing. 2) CS/pIRES2-EGFP-hBMP2-His nanoparticles were synthesized and pIRES2-EGFP-hBMP2-His was packaged by CS. 3) CS/pIRES2-EGFP-hBMP2-His nanoparticles were globular with an average size of 111.7 nm to 3,214.2 nm and an average zeta-potential of 4.93 mV to 16.79 mV.

CONCLUSIONCS/pIRES2-EGFP-hBMP2-His nanospheres are successfully synthesized.

OBJECTIVEThis study is conducted to explore new methods to perform surface biomodification of titanium implants and improve osteogenic efficiency.

METHODSAn RGD peptide and chitosan (CS) were combined by acylation reaction, forming RGD-CS. An RGD-CS/pDNA complex was subsequently prepared using a complex coacervation method and grafted on a pure titanium surface after physical and biochemical treatments were performed. The chemical structural characteristics of RGD-CS were evaluated using an infrared spectrometer and an elemental analyzer. The shape of this complex was then assessed by gel electrophoresis combined with atomic force microscopy. The grafting effect of this complex on the titanium surface was detected by EB staining.

RESULTSCS and RGD peptides were coupled by an amide bond. The RGD-CS/pDNA complex was completely composited at N/P > or = 2. Atomic force microscopy results showed that the morphology of this complex was mainly spherical. EB staining experiments showed that this complex was successfully grafted on the titanium plate.

CONCLUSIONRGD peptide-modified CS can be used as a titanium implant surface plasmid package carrier of pDNA.

Objective To compare the normal anatomy of the anterior cruciate ligament (ACL) of fresh frozen cadaveric knee specimen in oblique coronal thin-slice section with oblique coronal magnetic resonance imaging. Methods One fresh cadaveric knee specimen was scanned with MR T1-weighted spinecho sequence.then the specimen was frozen and sliced with a band saw along the oblique coronal plane into 1.0-mm-thick sections that corresponded to the MR images,MR images including oblique coronal T1-weighted and T2-weighted images of 50 normal the knee joints were retrospectively reviewed to observe the MR imaging features of the cruciate ligament. Results Anteromedial and posterolateral bundles of ACL were clearly depicted on both anatomic slices and MR images.The anteromedial bundles originated from the posteromedial aspect of the lateral femoral condyle,coursing through the lateral intercondylar notch in an anterior,inferior,and medial direction,and inserted on the anteromedial aspect of the intercondylar eminence. The posterolateral bundles originated from the anteromedial aspect of the lateral femoral condyle,passing laterally and inferiorly through the lateral intercondylar notch,and inserted on the posterolateral side of the intercondylar eminence.The full length of ACL of all 50 individuals was showed on MR images.MRI clearly differenitated the anteromedial and posterolateral bundles of ACL and depicted the full length of the bundles.similar to the findings on sectional anatomy.Conclusion Oblique coronal MR imaging is the best way to demonstrate ACL and should be used for clinically suspected injury of ACL.

Objective To discuss the diagnosis and surgical treatment for carotid body tumors (CBT). Methods Retrospective analysis was made on 16 cases of carotid body tumors hospitalized in Shandong Provincal Hospital from January 2003 to October 2010. All patients were diagnosed by digital subtraction angiography, including 3 case of Shamblin type Ⅰ,11 cases of Shamblin type Ⅱ and 2 cases of Shamblin type Ⅲ. Three cases of type Ⅰ and 3 cases of type Ⅱ underwent carotid body tumor resection. Three cases of type Ⅱ underwent carotid body tumor plus external carotid artery resection, 3 cases underwent carotid body tumor plus external carotid artery resection plus carotid artery repairment, 2 cases did carotid body tumor plus external carotid artery resection plus internal carotid artery reconstruction. One of type Ⅲ underwent carotid body tumor plus external carotid artery resection plus carotid artery repairment, and the other one underwent carotid body tumor plus external carotid artery resection plus internal carotid artery reconstruction. Results Diagnosis of CBT was confirmed by pathology in all cases. There was no postoperative death、hemiplegia and blindness. The cranial nerve injury was caused in 7 cases, accounting for 43. 75%. 13 cases ( 81. 25% ) were followed up for 2 to 76 months ( mean 42 months), no tumor recurrence and metastasis was found. Conclusions Digital subtraction angiography (DSA) is important in the diagnosis and therapy of carotid body tumor. Surgical treatment is the choice of therapy for carotid body tumors.

Objective:To investigate the biomechanical characteristics and clinical outcomes of arthroscopic superior capsular reconstruction for massive irreparable rotator cuff tears (MIRCT) using the long head of biceps tendon (LHBT) with tenotomizing its distally or not (the "Chinese way" ).Methods:Eight fresh-frozen cadaveric shoulders were used to create a MIRCT model by detaching the footprints of the supraspinatus and infraspinatus tendons on the greater tuberosity. LHBT autograft was transferred and securely fixed onto the footprint of supraspinatus tendon for superior capsular reconstruction. Further, all cadaveric specimens were assigned to the tenotomy group or reservation group (4 cadaveric specimens in each group) according to whether the distal part of LHBT was tentomized or not. Biomechanical tests were conducted to observe the stiffness, ultimate load of fixed LHBT and to measure the length between LHBT tear site and its insertion on the superior labrum. A total of 41 patients with MIRCT who underwent arthroscopic superior capsular reconstruction using LHBT autograft between July 2016 and December 2018 were enrolled in the study. There were 17 males and 24 females, aged from 46 to 76 years (62.6±7.3 years). All patients were assigned to the tenotomy group (23 cases) or reservation group (18 cases) according to whether the distal part of LHBT was tentomized or not. The visual analogue scale (VAS), University of California, Los Angeles (UCLA) score, American Shoulder and Elbow Surgeons (ASES) score, Constant-Murley score and Fudan University Shoulder Score (FUSS) were used to evaluate the clinical outcomes. The range of motion (ROM) of shoulder was recorded before and after operation. Magnetic resonance imaging was used to assess the structural integrity of reconstructed tissue at 12 months after operation (refers to the failure of the transposed LHBT, which may be accompanied by a retear of partial repaired supraspinatus tendon).Results:Biomechanical research showed that the stiffness, ultimate load of fixed LHBT and the length between LHBT tear site and its insertion on the superior labrum in the reservation group (54.0±6.6 N/mm, 141.8±15.9 N, 93.3±12.4 mm, respectively) were significantly higher than those in the tenotomy group (25.7±4.2 N/mm, 80.8±8.0 N, 47.4±2.0 mm, respectively) ( P<0.05). All patients were followed up for 12-18 months (14.5±1.8 months) without significant complications and adverse reactions. No matter the distal part of LHBT was tentomized or not, the ROM and clinical scores (VAS score, UCLA score, Constant-Murley score, ASES score and FUSS) of patients improved significantly at 1 year follow-up than that before operation ( P<0.05). However, there were no significant differences between the reservation group and tenotomy group in terms of postoperative ROM [flexion, abduction, external rotation at side, internal rotation (vertebral level) were 144.3°±15.5° vs. 148.0°±10.3°, 145.1°±14.1° vs. 142.3°±11.2°, 67.3°±14.4° vs. 62.7°±11.7°, 8.3±2.1 vs. 7.8±2.5, respectively], VAS scores (2.3±1.6 vs.1.5±1.2), functional scores (Constant-Murley score, UCLA score, ASES score and FUSS were 88.2±11.4 vs. 85.6±9.6, 29.3±2.8 vs. 31.4±3.5, 86.8±11.8 vs. 82.6±9.2, 92.1±10.1 vs. 88.3±8.2, respectively) and structural failures (35.2% vs. 30.0%, P>0.05). Conclusion:Arthroscopic superior capsular reconstruction using LHBT with reserving its distal part could achieve higher mechanics strength. However, the short-term follow-up showed that tenotomizing the distal part of LHBT exerted no obvious influence on postoperative function and structural integrity.

Objective To summarize and analyze the clinical and epidemiological characteristics of 585 cases of cutaneous sporotrichosis collected in Jilin province in the last 3 years. Methods A retrospective study was conducted on sporotrichosis cases diagnosed at the Department of Dermatology in the hospital from 2007 to 2009. Results Totally, 585 cases were included in this study. Among these patients, the male/female ratio was 1:1.35 with an average age of 40.5 years and average duration of symptoms of 6.78 months.The age at onset was mainly between 51 and 60 years (22.05%). Sporotrichosis seemed more frequently to occur in winter and spring. The majority (94.19%) of the patients were rural habitants, and 149 (25.47%) patients recalled history of trauma. Fixed form was the most common clinical presentation (56.58%), followed by lymphocutaneous form (39.66%), cutaneous disseminated form ( 1.88% ) and undefined form ( 1.88% ). The predilection sites of sporotrichosis were extremities (50.94%) and face (43.76%). The treatment of sporotrichosis included a 10% solution of potassium iodide, itraconazole and terbinafine alone or in combination. Two hundred and fifty patients were lost to follow up. Of the remaining 335 patients, 289 were cured with an average treatment duration of 2.09 months, 46 were still under follow-up or treatment. Conclusions The case load of sporotrichosis in Jilin province has remained high in recent years. The clinical and epidemic features of sporotrichosis cases in this report are similar to those in previous reports, but the proportion of middle-aged patients and atypical cases increases. Potassium iodide solution, itraconazole and terbinafine are effective and safe for the treatment of sporotrichosis.