BACKGROUND:Avascular necrosis of the femoral head is a refractory orthopedic disease that seriously affects the normal life of patients.Hip preservation is recommended for young patients due to the limited prosthesis longevity and revision.Accurate prediction of the mechanical properties of the necrotic area in the early stage and then intervention is the key to hip preservation. OBJECTIVE:To establish a dynamic contact mechanics finite element model of necrotic femoral head based on human hip CT data and predict effects of both necrotic volume magnitude and its position on biomechanics of the necrotic region under walking movement. METHODS:CT data of a volunteer were collected and then geometry model of the hip was rebuilt.Finite element model of the necrotic femoral head was established using the Abaqus software.Nine different necrotic femoral models were constructed by combined both three different necrotic volume magnitudes(small,medium and big volume)and three different necrotic positions(coincided with,medium deviated with and kept away from the line of the force).The Von Mises of the necrotic region for all models were predicted under both 3 000 N static load and dynamical loads of one whole ISO walking gait cycle.The collapse risk for all models was evaluated based on collapse criterion. RESULTS AND CONCLUSION:(1)More approaching of the necrotic region to the line of force and bigger collapse volume made the maximum Von Mises increasing.This also enlarged the collapse risk of the necrotic region.(2)For different load types,walking movement increased the maximum Von Mises of the necrotic region than that of the value under static load under the same necrotic volume and location.(3)In conclusion,dynamic load would result in increasing of the maximum Von Mises of the necrotic region comparing to static load during exercise.Therefore,the risk of local collapse will increase due to greater Von Mises.However,the overall collapse risk is lower than that of static load due to the dynamic change of bearing area.This factor should be carefully considered by surgeons when they evaluate the mechanical performance of the necrotic femoral head.

Objective:To evaluate the mechanical performance of customized metal prosthesis with tibia stems of varying lengths for tibial bone defects reconstruction.Methods:Morphologically matched postoperative finite element models of bone defect revision were developed, with three gradients (15 mm, 30 mm, and 45 mm) according to the degree of bone defect and were reconstructed with 3D printed tantalum metal prosthesis using three tibial stem lengths (80 mm, 120 mm, and 150 mm), respectively. Conventional static and dynamic (walking gait) loading was performed to analyze the peak tibial stress distribution and accumulated sliding distance at the prosthetic interface, and to assess the effects of the three tibial stems of different lengths on the stability of the customized tibial defect restorations and the internal tibial stress state.Results:The peak accumulated sliding distance of the dynamically loaded morphologically matched restorations ranged from 17.94 to 21.31 mm with static loading, which were 68% to 84.3% higher than those of 10.26 to 11.69 mm with static loading. The peak tibial stresses in the dynamically loaded model were greater than those in the statically loaded model, with an increase of 28%-49.2%, including 132.94-143.88 MPa in the statically loaded model and 170.41-200.14 MPa in the dynamically loaded model. The overall accumulated sliding distance of the tibia prosthetic model gradually decreased from the tibial osteotomy surface, and the accumulated peak sliding distances ranged from 10.26 to 11.69 mm for static loading, and from 17.94 to 21.31 mm for dynamic loading. The bone tissue stresses in the anterolateral and medial-posterior tibia increased gradually from top to bottom, and the maximum stress value in each section was in the posterior medial tibia (the maximum value was 200.14 MPa). The highest bone tissue stress in the lateral tibia was affected by the tibial stem length, which resulted in a different location, and it was the area most affected by stress shielding (maximum value of 170.65 MPa).Conclusion:For stability assessment of morphologically matched tantalum customized prosthesis, physiological gait dynamic loading studies are more reliable than static loading; the choice of tibial stem length depends on a combination of accumulated peak sliding distances and tibial bone stress distribution factors.

Temporomandibular joint (TMJ) diseases are common clinical conditions. The number of patients with TMJ diseases is large, and the etiology, epidemiology, disease spectrum, and treatment of the disease remain controversial and unknown. To understand and master the current situation of the occurrence, development and prevention of TMJ diseases, as well as to identify the patterns in etiology, incidence, drug sensitivity, and prognosis is crucial for alleviating patients′suffering.This will facilitate in-depth medical research, effective disease prevention measures, and the formulation of corresponding health policies. Cohort construction and research has an irreplaceable role in precise disease prevention and significant improvement in diagnosis and treatment levels. Large-scale cohort studies are needed to explore the relationship between potential risk factors and outcomes of TMJ diseases, and to observe disease prognoses through long-term follw-ups. The consensus aims to establish a standard conceptual frame work for a cohort study on patients with TMJ disease while providing ideas for cohort data standards to this condition. TMJ disease cohort data consists of both common data standards applicable to all specific disease cohorts as well as disease-specific data standards. Common data were available for each specific disease cohort. By integrating different cohort research resources, standard problems or study variables can be unified. Long-term follow-up can be performed using consistent definitions and criteria across different projects for better core data collection. It is hoped that this consensus will be facilitate the development cohort studies of TMJ diseases.

The application of digital technology in teaching and clinical practice has been hindered by the lack of integrity,consis-tency and accuracy in current digital models.Despite the efforts of domestic and international scholars,the localization,refining and standardization of model data for digital dental models remain inadequate,which limits the promotion and application of digital dental models.A preliminergly produced precise,standardized and multi-form applicable 3D dental-cranio-cervical digital model based on Chinese anatomical data is reported in this paper.The further improvement,application and promotion of this model are expected to contribute to the improvement of the quality of dental education and clinical efficiency.

Objective To investigate the effects of acute sleep deprivation on the behavior and synaptic protein expression of rats.Methods Seventy healthy male Wistar rats were randomly divided into seven groups,a Control group and sleep deprivation groups(24,48,72,96,120 and 144 hours).The sleep deprivation rat model was established by the modified multiplatform water environment sleep deprivation method.Spatial learning and memory were assessed by the Morris water maze.Anxiety was assessed by the open field test.The morphology and quantity of hippocampal neurons were observed by Nissl staining.Western blot and Real-time PCR were used to determine the expression of synaptophysin(SYN),post-synaptic density protein-95(PSD-95),and brain-derived neurotrophic factor(BDNF)in rats.Results Compared with the Control group,the numbers of standing and modification were significantly increased by prolongation of the sleep deprivation time(P＜0.05).The escape latency and path length were significantly increased in 120 and 144 h groups(P＜0.05),whereas the number of platform crossings and the percentage of the target quadrant time were significantly decreased(P＜0.01)and negatively correlated to the sleep deprivation time.The expression levels of BDNF,SYN,and PSD-95 were significantly decreased with the prolongation of sleep deprivation time(P＜0.01).Conclusions With the increase in sleep deprivation time,cognitive dysfunction and anxiety gradually deteriorated,which may be related to decreases in the expression of synaptic biomarkers.

Objective To investigate the causes of infertility and its pathological mechanism in female SD rats with spontaneous dwarfism(short stature rat,SSR).Methods Adult wildtype and SSR female SD rats were used in this study.A vaginal smear was used to observe changes in the motile cycle.Ovulation promotion was compared using the simultaneous estrus supernumerary ovulation method.Ovarian and uterine weight and body weight,and ovarian and uterine indices were measured.AMH,E2,FSH,LH,and FSH/LH levels in serum were measured.Transcriptome sequencing of ovarian tissues was performed to analyze gene expression differences.Results No abnormalities were observed in the estrous cycle of SSR female rats.The body weight of SSR female rats was significantly lower than that of wildtype rats,and their ovarian and uterine indices were significantly higher than that of wildtype rats.The mean number of ovulations was significantly higher in wildtype rats than in SSR female infertile rats(P<0.001).Serum AMH(P<0.01)and E2(P<0.05)levels were significantly higher in wildtype rats than in SSR female infertile rats,and serum levels of FSH,LH,and FSH/LH(P<0.05)were significantly lower in SSR infertile females than in SSR infertile rats,while PROG showed no significant difference.Transcriptome sequencing yielded 250 differentially expressed genes,including 190 upregulated and 60 downregulated genes.p53 signaling pathway and cytokine-cytokine receptor interaction.The MCC,MNC,EPC,and degree calculations of the CytoHubba plug-in were used to screen the top 10 significant nodes.The intersection was used to finally obtain nine hub genes,namely Cxcl1,Cxcl2,IL1a,IL1b,Cd80,Mmp13,Mmp8,Fgf3,and Ptgs2.Conclusions Infertility in SSR female rats may be related to a decreased ovarian reserve function and poor ovarian response.Cxcl1,Cxcl2,IL1a,IL1b,Cd80,Mmp13,Mmp8,Fgf3,and Ptgs2 were associated with infertility,laying a theoretical foundation to further explore infertility mechanisms.

Pregnancy in patients with Eisenmenger syndrome (ES) is associated with high maternal mortality rates of 30%‒50%, or even up to 65% in the case of a cesarean section (Yuan, 2016). Here, we report a case of term pregnancy complicated with ES and severe pulmonary artery hypertension (PAH), which was managed by a multidisciplinary team (MDT) and resulted in an uncomplicated delivery via elective cesarean section. The goal of this study is to emphasize the importance of multidisciplinary approach in the management of pregnancy with ES, which can profoundly improve maternal and infant outcomes.
Female ; Humans ; Pregnancy ; Cesarean Section ; Eisenmenger Complex/therapy* ; Hypertension, Pulmonary/therapy* ; Maternal Mortality ; Pregnancy Complications, Cardiovascular/therapy* ; Pregnancy Outcome

Objective:To systematically review the characteristics of sleep patterns in the elderly with subjective cognitive decline (SCD) and the relationship between subjective cognitive decline and sleep disorders.Methods:Observational studies on sleep patterns in the elderly with SCD were retrieved by computer in Chinese and English databases such as PubMed, Embase, Web of Science, ScienceDirect, China National Knowledge Infrastructure (CNKI) , WanFang Data and VIP, and the retrieval time was from the establishment of the database to March 31, 2020. Two researchers independently conducted article screening, data extraction and quality evaluation according to the standard. The random-effects model was used for Meta-synthesis of studies with data that could be pooled, and descriptive analysis for studies that could not be pooled.Results:A total of 12 articles were included, with a total sample size of 67 474 cases. The prevalence of SCD in the elderly was 25.9% (95% CI: 6.4%-52.5%) . The sleep patterns of the elderly with SCD were characterized by decreased total sleep time, prolonged wake-time after sleep onset, and frequent awakenings at night. Compared with the normal elderly, the elderly with SCD had a higher risk of poor sleep quality, insomnia and excessive daytime sleepiness ( OR=2.1, 1.15, 2.6) , and excessive daytime sleepiness (ESD) increased the risk of SCD in the elderly ( OR=6.06) . Conclusions:Compared with the normal elderly, the overall sleep quality of the elderly with SCD is poor, and sleep disorders can increase the risk of SCD in the elderly. Existing studies have differences in the diagnostic criteria of SCD, and future studies need to further confirm the causal relationship between SCD and sleep disorders in the elderly.

Objective:To investigate the correlation between mild cognitive impairment(MCI)and abnormal glucose metabolism and thus to provide a basis for MCI prevention.Methods:A total of 1 074 elderly outpatients with normal cognitive function and without confirmed diabetes mellitus, hyperlipoidemia or gout were enrolled.During a five-year follow-up period, 121 subjects were diagnosed with MCI based on the mini mental state examination(MMSE)and the Montreal cognitive assessment(MoCA). Furthermore, annual blood glucose and glycated hemoglobin monitoring was carried out to examine the long-term effects of abnormal glucose metabolism on MCI risk.Results:According to cognitive function, 1 074 subjects were divided into the MCI group and the non-MCI group.Compared with the non-MCI group, the mean values of fasting blood glucose(FBG), glycosylated hemoglobin(HbA1c), triglycerides(TG)and total cholesterol(TC)in the MCI group were elevated( P<0.05). The receiver operating characteristic(ROC)curve showed that the cut-off value of FBG was 6.2 mmol/L for the hyperglycemia group(sensitivity: 84.1%, specificity: 90.9%, area under curve: 0.875, P<0.001)and 4.5mmol/L for the hypoglycemic group(sensitivity: 77.4%, specificity: 87.3%, area under curve: 0.823, P<0.001); the cut-off value of HbA1c was 5.5%(sensitivity: 76.0%, specificity: 87.0%, area under curve: 0.815, P<0.001). Multiple Logistic regression analysis showed that increased risk of MCI was associated with the mean values of fasting blood glucose <4.5 mmol/L( RR: 1.69, 95% CI: 1.11-2.59)or ≥6.2 mmol/L( RR: 1.81, 95% CI: 1.15-2.86)and of glycosylated hemoglobin ≥ 5.5%( RR: 2.13, 95% CI: 1.51-2.99). Conclusions:Impaired fasting glucose tolerance and low fasting blood glucose are independent risk factors for MCI in the elderly.

Objective:To determine the relationship between uric acid (UA) and mild cognitive impairment (MCI), and its potential effect on inflammation.Methods:450 patients with MCI diagnosed by neuropsychological scale and 450 controls with normal cognitive function were included. All subjects were≥60 years old. There were 184 obese subjects in MCI group and 199 obese subjects in control group.Results:A correlation between increased serum UA level and decreased risk of MCI was found in all MCI patients and non-obese MCI patients ( OR: 0.60, 95% CI 0.45-0.78; OR: 0.42, 95% CI 0.29-0.62), but not in obese MCI patients ( OR: 0.86, 95% CI: 0.54-1.35). The levels of UA and hypersensitive C reactive protein (hs-CRP) in obese patients with MCI were higher than those in non-obese patients ( P<0.01). There was a linear positive correlation between serum UA and hs-CRP levels in obese patients with MCI ( r=0.505, P<0.01), but not in non-obese MCI patients ( r=0.053, P=0.385). Conclusion:A significant correlation between lower serum uric acid levels and higher risk of MCI in non-obese subjects was found. Inflammation caused by obesity may weaken this relationship.