Objective As estrogen increases visceral hypersensitivity induced by water avoidance stress in female rats,further experiment was designed to determine whether the influence of estrogen involves NR2B.Methods Healthy adult female Wistar rats were bilaterally ovariectomized,and then housed individually.Implantation of cannula into lateral cerebroventricle and electrodes into the abdominal muscle had been done.After 5 days recovery,rats with abnormal behavior and ehctromyography were excluded,finally a total of 48 rats were eligible,and were equipped for abdominal muscle electromyography and submitted to water avoidance stress(WAS).Visceromotor response(VMR)to 20,40,60 and 80 mmHg colorectal distension(CRD)was recorded in rats intracerebroventricular-infused with either 17β-estradiol,normal saline,AP5(NMDA receptor-antagonist)or Ro25-6981(NR2B antagonist).NR2B mRNA in anterior cingulate cortex or dorsal root ganglia were compared by real-time PCR between the rats treated with 17β-estradioI and that with normal saline.Results Bilaterally ovarieetomized rats treated with 17β-estradiol,exhibited more visceral hypersensitivity after WAS than that with normal saline on 40,60 and 80 mmHg CRD(P=0.039,P=0.033,P=O.001).The VMR on 40 and 60 mmHg CRD in 17β-estradiol treated group was not significantly different from that in 17β-estradiol plus Ro25-6981 treated group.Whilst,significant differences of VMR were noted between 17β-estradiol treated group and 17β-estradiol plus Ro25-6981 treated group on 80 mmHg CRD,17β-estradiol treated group and 17β-estradiol plus AP5 treated group on 60,80 nmmHg CRD,respectively.17β-estradiol increased NR2BmRNA in anterior cingulate cortex(0.57±0.41 vs 0.21±0.13,P=0.048),but not in dorsal root ganglia(0.35±0.45 vs 0.38±0.31,P=0.465). Stress-induced visceral hypersensitivity in the hormonally-restored visceral hyper-responsiveness of bilaterally ovariectomized rats was antagonized by AP5 or Ro25-6981.Conclusions Estrogen may be mediated through NR2B activation to enhance visceral sensitivity in female stressed rats,that probably related with the increased expression of NR2B mRNA in anterior cingulate cortex.

BACKGROUND:Oligo(poly(ethylene glycol)fumarate) (OPF) hydrogel is a kind of biomaterial with good biocompatibility, injectability, and biodegradability. It is known that there are differences in the characteristics of hydrogels with different molecular weights. Under osteogenic induction, bone marrow mesenchymal stem cels encapsulated in the suitable molecular weight hydrogel have better proliferation and differentiation. Therefore, the use of OPF hydrogel provides new options for bone tissue-engineered scaffold.
OBJECTIVE:To investigate the effect of OPF hydrogel with different molecular weights on the proliferation and differentiation of encapsulated rat bone marrow mesenchymal stem celsin vitro.
METHODS: Four kinds of OPF hydrogels with molecular weights of 1 000, 3 000, 10 000 and 35 000 were developed by OPF crosslinking with a redox radical initiation system. Hydrogel sweling and degradation properties were detected. Afterwards, bone marrow mesenchymal stem cels encapsulated in different hydrogels were cultured in osteogenic medium for 1-3 weeks. The effects of hydrogels on morphplogy of bone marrow mesenchymal stem cels and osteogenic differentiation were detectedvia histological staining (hematoxylin-eosin staining and alizarin red staining) and immunofluorescence staining.
RESULTS AND CONCLUSION: With the increase of molecular weight of hydrogels, the gelation time was shortened, the sweling ratio significantly increased, and the hydrogel degradation rate was proportional to the molecular weight. In addition, the number of mineralized nodules formed in 3 000 and 10 000 molecular weight hydrogels was more than that in the other hydrogels, indicating that hydrogels with appropriate sweling and degradation properties are beneficial to cel proliferation and differentiation. In conclusion, OPF hydrogels have good biocompatibility and hydrogels with 3 000 and 10 000 molecular weight play active regulatory roles in osteogenic differentiation of mesenchymal stem cels.

Objective To compare the clinical efficacy of 25G+and 27G+pars plana vitrectomy(PPV)in the treat-ment of idiopathic epiretinal membrane(iERM).Methods A total of 50 iERM patients(50 eyes)who were admitted to the Third Affiliated Hospital of Xinxiang Medical University from December 2019 to August 2022 were selected as the research subjects.These patients were divided into the control group and observation group based on different surgical methods,with 25 patients(25 eyes)in each group.Patients in the control group received 25G+PPV treatment,while patients in the observation group received 27G+PPV treatment.The surgical duration and postoperative 1-day incision subconjunctival hemorrhage and e-dema of patients in two groups were compared;central macular thickness(CMT)was measured by optical coherence tomo-graphy before surgery,1 day,1 week,1 month,and 3 months postoperatively in the two groups.Visual acuity of patients in both groups was assessed according to the early treatment diabetic retinopathy study(ETDRS)visual acuity chart.Intraocular pressure was measured by using a non-contact Callon tonometer.Complications,such as intraoperative macular injury,retinal hole,postoperative choroidal detachment,retinal hemorrhage,retinal detachment,and intraocular infection,were observed in both groups.Results The surgical duration of patients in the observation group was significantly shorter than that in the control group(t=2.314,P＜0.05).The extent of subconjunctival hemorrhage and edema of patients in the observation group was significantly smaller than that in the control group(t=13.706,P＜0.01).The ETDRS visual acuity of patients at 1 day,1 week,1 month,and 3 months after surgery in both groups was significantly higher than that before surgery(P＜0.05).There was no signifi-cant difference in ETDRS visual acuity of patients between the two groups at 1 day,1 week,1 month,and 3 months postoperatively(P＞0.05).At 1 day after surgery,the intraocular pressure of patients in the observation group was significantly higher than that in the control group(P＜0.05).At 1 week,1 month,and 3 months after surgery,there was no significant difference in intraocular pressure of patients between the two groups(P＞0.05).Two patients in the control group experienced transient ocular hypotension 1 day after surgery,while no such complication was observed in the observation group.Patients in both groups presented with varying degrees of retinal nerve epithelial layer traction,retinal edema,thickening,and vascular distortion before surgery.At 1 day after surgery,epiretinal membrane traction was relieved in both groups,and there was a significant improvement in the anatomical structure of the macular area compared to preoperative conditions.At 1 day,1 week,1 month,and 3 months after surgery,the CMT of patients in both groups was reduced compared to preoperative values(P＜0.05);there was no significant difference in CMT of patients between the two groups at 1 day,1 week,1 month,and 3 months after surgery(P＞0.05).In the control group,18 eyes(72.0％)were sutured at the scleral puncture sites due to leakage,while no suturing was performed in the observation group.Patients in both groups completed the surgery successfully,without any intraoperative complications such as macular injury or retinal hole.During the 3-month follow-up,no postoperative complications such as choroidal detachment,retinal hemorrhage,retinal detachment,or intraocular infection were observed in both groups.Conclusion Both 27G+PPV and 25G+PPV have good clinical effects and high surgical safety in the treatment of iERM.Compared with 25G+PPV,27G+PPV can shorten the surgical duration,better maintain postoperative intraocular pressure stability,and reduce the range of subconjunctival bleeding and edema.

Objective To study the influence of foot progression angle on tibial shock during running. Methods The normal, toe-in and toe-out gait of fifteen healthy adults was tested during running trials on a treadmill. The differences in tibial shock (impact peak, average loading rate, instantaneous loading rate and maximum tibia acceleration) for runners at different foot progression angles were analyzed to explore the influence of foot progression angle on tibial shock. The changes in sagittal plane trunk angle, strike pattern, stride frequency and step width of runners under three gaits were also compared to explore its possible causes. Results Compared with normal gait, the maximum tibial acceleration of toe-in and toe-out gait was increased by 19.3% and 24.5%, impact peak was increased by 7.6%, average loading rate was increased by 7.9% and 9.5%, instantaneous loading rate was increased by 3.9% and 10-.9%, with significant statistic differences. No significant changes were found in sagittal plane trunk angle, strike pattern, stride frequency and step width. Conclusions Foot progression angle might be an another gait parameter which affected tibial shock during running in addition to other related known gait parameters such as sagittal plane trunk angle, strike pattern, stride frequency and step width，which would provide an important reference for prevention of tibial stress fracture.

Intraoral three-dimensional scanning technology has been adopted in stomatology field and developed rapidly with improved accuracy. At present, the scanning accuracy of the intraoral three-dimensional scanners used in restoration of single crown, three unit fixed partial bridge and single implant crown satisfies the clinical requirements. While for restoration of multi-unit fixed, the scanning accuracy is not enough. There are still technical bottlenecks for scanning functional motion boundary of soft tissue, especially for direct acquisition of edentulous functional impressions. Through literature review and analysis, we summarize the intraoral scanning accuracy of oral hard and soft tissues, and analyze the clinical applicability and limitations of intraoral scanning technology, providing reference for clinical application.

Objective:To establish a standard method to evaluate the scanning accuracy of intraoral scanner (IOS) and to investigate six IOS′s scanning accuracy and the relationship between different scan span.Methods:Five simplified six abutments full arch model were fabricated by high accuracy (5 μm) milling machine with 7075 aluminum alloy. The machining accuracy, which was verified by a coordinate measuring machine with higher accuracy (0.7 μm), was considered as the reference accuracy. The model with the highest machining accuracy was considered as the test model in IOS′s scanning accuracy test, and computer-aided design (CAD) data of the model was used as the reference data. Six IOS scanned the test model 10 times with the same scanning path, obtained 60 test data. CAD data and test data were input into Geomagic Studio 2014. The preparation part above the margin of the abutments of the data was isolated and divided into 4 segments of interest: single crown, three-unit bridge, five-unit bridge, and full arch. The test data were then best-fit aligned to CAD data or each other followed by deviation analysis. Scanning trueness and precision were then calculated.Results:The mid-value of scanning trueness and precision of six IOS in single crown, three-unit bridge, five-unit bridge and full arch were 13.3-29.6 μm and 7.6-20.7 μm, 15.4-30.9 μm and 8.7-26.5 μm, 17.0-66.1 μm and 11.3-44.2 μm, 24.0-107.9 μm and 24.6-150.1 μm respectively.Conclusions:Long-span scanning can affect the accuracy of IOS to a varying extent.