Objective To establ ish sophisticated three-dimensional finite element model of the lower cervical spine and reconstruct lower cervical model by different fixation systems after three-column injury, and to research the stress distribution of the internal fixation reconstructed by different techniques. Methods The CT scan deta were obtained from a 27-year-old normal male volunteer. Mimics 10.01, Geomagic Studio10.0, HyperMesh10.0, and Abaqus 6.9.1 softwares were usedto obtain the intact model (C3-7), the model after three-column injury, and the models of reconstructing the lower cervical spine after three-column injury through different fixation systems, namely lateral mass screw fixation (LSF) and transarticular screw fixation (TSF). The skull load of 75 N and torsion preload of 1.0 N?m were simulated on the surface of C3. Under conditions of flexion, extension, lateral bending, and rotation, the Von Mises stress distribution regularity of internal fixation system was evaluated. Results The intact model of C3-7 was successfully establ ished, which consisted of 177 944 elements and 35 668 nodes. The results of the biomechanic study agreed well with the available cadaveric experimental data, suggesting that they were accord with normal human body parameters and could be used in the experimental research. The finite element models of the lower cervical spine reconstruction after three-column injury were establ ished. The stress concentrated on the connection between rod and screw in LSF and on the middle part of screw in TSF. The peak values of Von Mises stress in TSF were higher than those in LSF under all conditions. Conclusion For the reconstruction of lower cervical spine, TSF has higher risk of screw breakage than LSF.
Objective Metal wear products cause the aseptic loosening of joint prosthesis. To investigate the effect of metal ions Co2+ and Cr3+ on the osteoblast apoptosis, cell cycle distribution, and secretion of alkal ine phosphatase (ALP), and to search a method to prevent and treat aseptic loosening. Methods The mouse calvarial osteoblasts (MC3T3-E1) were cultured in vitro to 3-5 generations (5 × 105 cells/ mL) and divided into 2 groups: the experimental group and the controlgroup. The osteoblasts were cultured in α-MEM medium containing 10%FBS (the control group), and the mixed solution ofCoCl2 and CrCl3 was added after the osteoblasts cultured in α-MEM medium containing 10%FBS attached completely (the experimental group). At 12, 24, and 48 hours after culture, the osteoblast apoptosis and the cell cycle distribution were assessed by flow cytometry; and ELISA method was appl ied to detect ALP content in serum supernatant. Results At 12, 24, and 48 hours after culture, the apoptosis rates in the experimental group (13.90% ± 0.52%, 14.80% ± 0.41%, and 13.40% ± 0.26%) were significantly higher than those in the control group (8.56% ± 0.31%, 8.19% ± 0.24%, and 2.15% ± 0.11%), (P lt; 0.05); G2M (dividing phase) distribution ratio significantly decreased and G0G1 (dormancy stage) distribution ratio significantly increased when compared with those in the control group (P lt; 0.05); and the absorbency (A) values of ALP were 0.955 ± 0.052, 0.624 ± 0.041, and 0.498 ± 0.026 in the exprimental group, and were 1.664 ± 0.041, 1.986 ± 0.024, and 2.192 ± 0.041 in the control group, showing significant differences between 2 groups (P lt; 0.05). Conclusion Metal ions Co2+ and Cr3+ have a marked effect on osteoblasts cell cycle distribution, which can make most of the cells to be in dormancy stage (G0G1), up-regulate the apoptosis rate and inhibit the releasion of ALP from osteoblasts.
ObjectiveTo investigate the associations of preoperative red cell distribution width (RDW) with mortality and morbidity in patients underwent liver transplantation. MethodsThis investigation was a retrospective study, the patients underwent liver transplantation met the inclusion criteria from June 2017 to May 2020 in the West China Hospital of Sichuan University were enrolled. The patients were divided into RDW≤14.5% group and RDW>14.5% group according to the normal RDW critical value (14.5%). The propensity score matching (PSM) was used to adjust the baseline characteristics. The primary outcome was 1-year mortality. The secondary outcomes included 1-year survival, 30-day mortality, incidence of early allograft dysfunction, acute kidney injury, renal replacement therapy, and pulmonary complications, as well as ICU stay and postoperative hospital stay. ResultsA total of 303 patients who met the analysis conditions were included. After PSM, 57 patients in each group were matched. There were no significant differences between the two groups in the baseline data such as the gender, age, body mass index (BMI), initial diagnosis, MELD score, Child-Pugh grade of the recipients, and the gender, age, and BMI of the donors (P>0.05). The 1-year [22.8% (13/57) versus 5.3% (3/57), χ2=7.27, P=0.007] and 30-day [15.8% (9/57) versus 3.5% (2/57), χ2=4.93, P=0.026] mortality of the patients with RDW >14.5% were higher than that of the patients with RDW ≤14.5% . The Kaplan-Meier survival curve showed that the 1-year survival of the patients with RDW ≤14.5% after liver transplantation was better than that of the patients with RDW >14.5% [hazard ratio=4.75, 95%CI (1.78, 12.67), P=0.007], but there were no significant differences between the two groups in the incidence of early graft dysfunction, acute renal injury, renal replacement therapy, and pulmonary complications, as well as postoperative hospital stay and ICU stay (P>0.05). ConclusionPreliminary results of this study indicate that preoperative RDW of patients underwent allogeneic liver transplantation is associated with1-year mortality, 30-day mortality, and 1-year survival.
Objective To study the predictive value of red blood cell distribution width in severity stratification of community-acquired pneumonia(CAP). Methods One-hundred and seventeen CAP patients admitted between August 2014 and August 2015 were recruited in the study.According to the severity of CAP evaluated by pneumonia severity index (PSI)and CURB score,the patients were divided into a severe group,a moderate group and a mild group with 39 cases in each group.Meanwhile 39 healthy volunteers were recruited as control.The blood red blood cell distribution width and high sensitive C-reactive protein(hs-CRP)levels were measured in all subjects. Results The PSI score and CURB score were significantly higher in the CAP patients than the control group and increased with the deterioration of the disease.The red blood cell distribution width and hs-CRP level were also significantly higher in the CAP patients than the control group and increased with the deterioration of the disease (P<0.05). Conclusion The red blood cell distribution width is correlated with the severity of CAP and has predictive value in CAP severity stratification.
Objective To compare the effect of two different methods of cell seeding on spatial distribution and gene expression of hBMSCs in biocoral scaffold in vitro cultures. Methods The composite of hBMSCs and biocoral scaffold was prepared by traditional seeding (group A) and fibrin glue seeding (group B). The seeding efficiency was measured after 30 minutes of incubation in group B and after 3 hours in group A. At 2, 7, 14 and 21 days after culture, the samples were harvestedand the serial longitudinal sections were cut for each embedded composite. The sections were stained with DAPI and were measured using fluorescence microscope with apotome under serial optical sections. The cell number in every 10 × objective field was automatically measured by AxioVision image analysis software and levels (from seeding surface to bottom L1-L5) or columns (from centre to margin) for comparing cell distribution were set up. The specific osteogenic genes [osteonectin (ON), core binding factor α1 (Cbfα1), osteocalcin (OC)] expression was measured by RT-PCR. Results The seeding efficiency was significantly higher in group B (88.32% ± 4.2%) than in group A (66.51% ± 12.33%, P lt; 0.01). At 2 days after culture, the cell number from L1 to L4 decreased gradully in two groups (P lt; 0.05); in the cell number of different columns, there was no significant difference in group A (Pgt; 0.05) whereas significant difference in group B (P lt; 0.05); there was no significant difference in gene expression between two groups (P gt; 0.05). At 7 days after culture, the cell number was less than that at 2 days in group A and there was significant difference among levels (P lt; 0.05). The cell number and osteogenic gene expression increased sharply and there appeared uniform cell distribution in group B (P gt; 0.05). The gene expression of ON and Cbfα1 in group B was higher than that in group A (Plt; 0.05). At 14 days after culture, the cell number in levels or columns in group A decreased sharply and was less than that at 7 days (P lt; 0.05); whereas the cell number was similar to that at 7 days in group B (P gt; 0.05). The OC gene expression reached the highest level in group B at 14 days. The gene expression was higher in group B than in group A (P lt; 0.05). At 21 days after culture, there was significant difference in the cell number among levels and in the gene expression between group A and group B (P lt; 0.05); there was no significant difference in the cell number among columns in two groups (Pgt; 0.05). In addition, the cell number of most levels and columns in group B was more than that in group A at 7, 14 and 21 days after culture (P lt; 0.05). Conclusion More uniform cell distribution with rapid prol iferation and osteogenic differentiation is available in different levels or columns of scaffold by fibrin glue seeding than by traditional seeding.
Three dimensional (3D) printing is considered as an advanced manufacturing technology because of its additive nature. Electron beam melting (EBM) is a widely used 3D printing processes for the manufacturing of metal components. However, the products printed via this process generally contain micro porosities which affect mechanical properties, especially the fatigue property. In this paper, two types of EBM printed samples of the Ti-6Al-4V alloy, one with a round cross section and the other with a triangle cross section, were employed to investigate the existence of porosities using computed tomography (CT). Statistical analyses were conducted on the number, volume, shape, and distribution of pores. The results show that small pores (less than 0.000 2 mm3) account for 80% of all pores in each type of samples. Additionally, to some extent, the shape of sample has influence on the number of micro porosities in EBM made Ti-6Al-4V. The sphericity of the pores is relatively low and is inversely proportional to pore volume. It is found that re-melting on the free surface effectively reduce pore density near the surface. This study may help produce a medical implant with better fatigue resistance.
ObjectiveTo analyze the clinical characteristics and geographical distribution of Keshan disease in Chongqing city for prevention and disease control. MethodsWe collected the clinical data of patients with Keshan disease from 2008 to 2012 in Liangping, Shizhu, Fengdu and Dianjiang counties as well as Wanzhou district of Chongqing city including the medical history, physical examination, results of laboratory tests to analyze the clinical characteristics and geographical distribution. ResultsFifty-eight patients were included from Liangping (n=21), Shizhu (n=25), Fengdu (n=11) and Dianjiang (n=1). The number of patients with potential and chronic Keshan disease was 16 and 42, respectively. The average age of patients was 54.91±15.53 years. The proportion above age 60 was 32.76% and below age 10 was 3.45%. The patients had main clinical signs as heart enlargement (36.76%), low-weak first heart sound (22.41%), systolic murmur (10.34%), arrhythmia (8.62%), etc. Abnormal ECG detection rate was 98.28%, with common types followed by sinus rhythm (37.93%), complete right bundle branch block (25.86%), ST-T changes (24.14%), left ventricular hypertrophy (15.52%), atrial fibrillation (13.79%), occasional ventricular premature (10.34%), T changes (10.34%), sinus bradycardia (8.62%), and incomplete right bundle branch block (6.90%). X-ray results showed that heart enlargement accounted for 82.76%. The ratios of mild, moderate and significant expansion of the heart were 46.55%, 27.59%, and 8.62%, respectively. ConclusionIn recent years, most patients with Keshan disease in Chongqing are chronic type at older age. The main clinical symptom is heart enlargement with high abnormal ECG detection rate.
ObjectiveTo observe the volume and distribution of necrotic tissue of femoral head in steroid-induced osteonecrosis of femoral head (SONFH) patients by three-dimensional reconstruction of CT.MethodsA clinical data of 25 patients with SONFH between September 2016 and December 2018 was analyzed. There were 22 males and 3 females, with an average age of 38.8 years (range, 20-63 years). The necrosis of the femoral head was in stage Ⅱ of Association Research Circulation Osseous (ARCO). The disease duration ranged from 3 to 18 months, with an average of 9.2 months. A three-dimensional reconstruction with CT data of SONFH patients were performed by Mimics Research 21.0 software and the femoral head was segmented into eight regions by 3-matic Research 13.0 software. The volume of necrotic tissue of the femoral head and the volume rate of necrotic tissue to femoral head were calculated and the distribution was also analyzed.ResultsThe three-dimensional digital model of the femoral head showed that the necrotic tissue of the femoral head was located above the anterior superior medial, and the area of the necrotic tissue was in a dome-like shape. The results showed that the necrotic tissue in the femoral head was mainly concentrated on the anterior superior internal area, the anterior superior outer area, and the posterior superior internal area. The volume of femoral head was (48 399.52±9 408.90) mm3, and the volume of necrotic tissue was (20 917.08±6 566.94) mm3, and the volume ratio of necrotic tissue to femoral head was 44.75%±15.72%. The proportion of necrotic volume in different regions was different, and the necrotic tissues were mainly distributed in the anterior superior internal area, the anterior superior outer area, and the posterior superior internal area.ConclusionThe volume and distribution of necrotic tissue in femoral head can be evaluated quickly and intuitively by three-dimensional reconstruction of CT in Mimics software.
ObjectiveTo study the clinical distribution and the change of drug resistance of Acinetobacter baumannii from different inpatient specimens sources during 2008 to 2012, and to provide guidance for rational use of antibiotics. MethodsThe identification of Acinetobacter baumannii was conducted by VITEK-2 based on clinical and laboratory standards institute (CLSI) guideline between January 2008 and December 2012. The susceptibility of antibiotics was determined by K-B test, and data analysis was conducted by Excel and SAS. ResultsA total of 3 139 stains of Acinetobacter baumannii were isolated from 2013 patients during this period. The Acinetobacter baumannii was mainly obtained from the Burn ward, Intensive Care Unit ward and Thoracic ward. Sputum was the most specimens of Acinetobacter baumannii, accounting for 48.4%. The drug resistance rates of Acinetobacter baumannii to most of the antimicrobial agents were more than 55%. Compound antibacterial is more effective than the single drug ingredient. Compared with other antimicrobial agents, β-lactams/β-lactamase inhibitor compound and carbapenems antimicrobial agents were more sensitive. ConclusionThe drug resistance of Acinetobacter baumannii is serious and has differences among hospitals. Clinicians should monitor the drug resistance of Acinetobacter baumannii timely and choose proper antibiotics according to the results of drug sensitivity.
Objective To monitor the distribution of blood perfusion during aortic arch aneurysm surgery under double arterial lines with single pump. Methods We retrospectively analyzed the clinical data of 37 patients underwent aortic arch repair or reconstruction between September 2012 and April 2014. There were 9 females and 28 males at mean age of 48.1±10.8 years ranging from 19.0-72.0 years.We took double arterial lines with single pump for cardiopulmonary bypass (CPB) during the operation and we monitored the perfusion tube flow of both the upper and lower body by blood flow detector. Cerebral blood perfusion was measured by transcranial cerebral Doppler and near-infrared spectroscopy cerebral oxygen saturation (rSO2). Results The mean CPB time of all 37 patients was 195.8±40.5 minutes ranging from 136.0-277.0 minutes and the mean duration time of selective antegrade cerebral perfusion (SCAP) was 21.6±5.6 minutes ranging from 5.0-35.0 minutes. During cooling and rewarming phases, the part of blood flow through axillary artery cannulation ranged from 31.5% to 40.8% of the whole body perfusion. The blood flow of SACP was increased to 15.0 ml / (kg·min) in 2 patients with significantly lower rSO2 and middle cerebral artery blood flow during SACP, and they had an uneventful recovery process after surgery. There were another 2 patients recorded abnormal situation of rSO2 without interventions. One patient died and the other one recovered with compications of spinal cord. Conclusions The technique of double arterial lines with single pump is reasonable and effective. The cerebral perfusion monitoring is helpful to detect abnormal perfusion during aortic arch aneurysm surgery.