ObjectiveStudy how to quantify the bias of each study and how to estimate them.
MethodIn the random-effect model, it is commonly assumed that the effect size of each study in meta-analysis follows a skew normal distribution which has different shape parameter. Through introducing a shape parameter to quantify the bias and making use of Markov estimation as well as maximum likelihood estimation to estimate the overall effect size, bias of each study, heterogeneity variance.
ResultIn simulation study, the result was closer to the real value when the effect size followed a skew normal distribution with different shape parameter and the impact of heterogeneity of random effects meta-analysis model based on the skew normal distribution with different shape parameter was smaller than it in a random effects metaanalysis model. Moreover, in this specific example, the length of the 95%CI of the overall effect size was shorter compared with the model based on the normal distribution.
ConclusionIncorporate the bias of each study into the random effects meta-analysis model and by quantifying the bias of each study we can eliminate the influence of heterogeneity caused by bias on the pooled estimate, which further make the pooled estimate closer to its true value.
In order to check the neck response and injury during motor vehicle accidents, we developed a detailed finite element model for human cervical spine C4-C6. This model consisted of cortical bone, cancellous bone, annulus, nucleus, ligaments and articular facet, and it also set up contact in the contacting parts for simulating the movement perfectly under frontal impact. This model could be used for stress and strain distribution after the frontal impact load was applied on this model. During the process of frontal impact, the most displacement simulated data were in the interval range of experimental data. The experimental results showed that this model for the human cervical spine C4-C6 simulated the movement under the frontal impact with fidelity, and reflected the impact dynamics response on the whole.
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.
Objective To analyze the differences in microbial communities in bronchoalveolar lavage fluid (BALF) from patients with simple pneumonia versus those with chronic obstructive pulmonary disease (COPD) combined with lower respiratory tract infection using metagenomic next-generation sequencing (mNGS). Methods Patients hospitalized for pulmonary infections at the First Affiliated Hospital of Xinjiang Medical University between December 2021 and March 2023 were included. Based on the presence of COPD, the patients were divided into two groups: those with simple pneumonia and those with COPD combined with lower respiratory tract infection. mNGS was employed to detect microbes in BALF, and the microbial community distribution characteristics of the two groups were analyzed. Results A total of 97 patients were included, of whom 80 (81.82%) had positive microbial detection results. The smoking index in COPD group with lower respiratory tract infection was significantly higher than that in the group with simple pneumonia (t= ?3.62, P=0.001). Differences in microbial community distributions were observed between the groups. At the genus level, 19 species of microorganisms were detected in the simple pneumoniapulmonary infection group, including 8 bacteria (42.11%), 2 fungi (10.53%), 3 viruses (15.79%), and 6 other types of microorganisms (31.58%). In contrast, 22 types of microbes were detected in COPD group with lower respiratory tract infection, including 10 bacteria (47.62%), 3 fungi (14.29%), 4 viruses (19.05%), and 4 other types of microorganisms (19.05%). Differences were also noted in reads per million (RPM) values; bacterial RPM values at the genus level were significantly higher in the COPD group during non-severe pneumonia compared to the simple pneumonia group (Z=–2.706, P=0.007). In the patients with severe pneumonia, RPM values at the genus and species levels were significantly higher than those in non-severe pneumonia (Z=?2.202, P=0.028; Z=?2.141, P=0.032). In COPD combined with severe pneumonia, bacterial RPM values were significantly higher at the species level compared to non-severe pneumonia (Z=?2.367, P=0.017). ConclusionsThere are differences in the distribution of microbial communities at the genus and species levels in BALF from patients with COPD combined with lower respiratory tract infection compared to those with simple pulmonary pneumonia. Bacteria are the predominant microbial type in both groups, but the dominant bacterial species differ between them. Simple pneumonia are primarily associated with bacterial, viral, and other types of microbial infections, while COPD combined with lower respiratory tract infection is predominantly associated with fungal and bacterial infections. RPM values may serve as an indicator of the severity of pneumonia.
ObjectiveTo systematically evaluate the association between red cell distribution width (RDW) and prognosis of patients with acute ischemic stroke (AIS) undergoing intravenous thrombolytic therapy.MethodsWe searched the PubMed, Embase, Cochrane Library, Web of Science, Chinese Biomedical Literature Service System, China National Knowledge Infrastructure, Wanfang database, and CQVIP database to identify eligible studies evaluating the relation between RDW and prognosis in AIS patients receiving intravenous thrombolysis from the establishment of databases to May 2021. The Newcastle-Ottawa Scale was used to evaluate the literature quality, and RevMan 5.3 software was used to process the data. The relationship between RDW and prognosis in AIS patients treated with intravenous thrombolytic therapy was analyzed using odds ratio (OR) and 95% confidence interval (CI).ResultsFive studies with a total of 1 269 participants were included into this meta-analysis. All the studies were retrospective case-control studies. Because of statistical heterogeneity (I2=59%, P=0.04), random-effects model was chosen. Meta-analysis result showed that among AIS patients who received intravenous thrombolysis, those with elevated RDW before thrombolysis were more likely to have poor prognosis than those without elevated RDW [OR=1.50, 95%CI (1.14, 1.98), P=0.004].ConclusionElevated RDW is associated with adverse outcome of AIS patients treated with thrombolysis, and may be a risk factor for poor prognosis in patients treated with thrombolytic therapy.
Stress distribution of denture is an important criterion to evaluate the reasonableness of technological parameters, and the bite force derived from the antagonist is the critical load condition for the calculation of stress distribution. In order to improve the accuracy of stress distribution as much as possible, all-ceramic crown of the mandibular first molar with centric occlusion was taken as the research object, and a bite force loading method reflecting the actual occlusal situation was adopted. Firstly, raster scanning and three dimensional reconstruction of the occlusal surface of molars in the standard dental model were carried out. Meanwhile, the surface modeling of the bonding surface was carried out according to the preparation process. Secondly, the parametric occlusal analysis program was developed with the help of OFA function library, and the genetic algorithm was used to optimize the mandibular centric position. Finally, both the optimized case of the mesh model based on the results of occlusal optimization and the referenced case according to the cusp-fossa contact characteristics were designed. The stress distribution was analyzed and compared by using Abaqus software. The results showed that the genetic algorithm was suitable for solving the occlusal optimization problem. Compared with the reference case, the optimized case had smaller maximum stress and more uniform stress distribution characteristics. The proposed method further improves the stress accuracy of the prosthesis in the finite element model. Also, it provides a new idea for stress analysis of other joints in human body.
Objectives To investigate the effect of the combined treatment with probiotics and lactulose of gastrointestinal function and postoperative infection after open cardiac surgery.
Methods We retrospectively analyzed the clinical data of 264 patients underwent cardiopulmonary bypass in our hospital between August 2013 and June 2014. There were 129 males and 135 females at the mean age of 53.06±10.97 years. We divided those patients into a treatment group and a control group. In the treatment group, there were 58 males and 63 females at the mean age of 52.29±14.31 years. They took probiotics and lactulose from the first day to the seventh day after operation. In the control group, there were 71 males and 72 females at the mean age of 52.29±14.31 years. They didn’t take probiotics or lactulose after the surgery. Procalcitonin (PCT) and lipopolysaccharides (LPS) concentrations were measured before operation, at 24 hours postoperatively, at 72 hours and on the seventh day. We recorded the condition of postoperative infection, gastrointestinal disorders and relative informations.
Results The PCT and LPS concentrations in the treatment group after 72 hours postoperatively were statistically lower than those of the control group (1.04±5.39 ng/ml vs. 3.51±4.28 ng/ml, P=0.04; 11.28±4.34 EU/ml vs. 21.59±7.34 EU/ml, P=0.03). The PCT and LPS concentrations in the treatment group were also statistically lower than those of the control group on the 7th day postoperatively (0.17±2.79 ng/ml vs. 1.98±4.62 ng/ml，P=0.04; 6.74±6.38 EU/ml vs. 15.96±4.61 EU/ml, P=0.01). The ICU stay time (43.25±14.36 h vs. 63.47±24.46 h, P=0.01) and postoperative hospital stay time (15.07±4.52 d vs. 21.08±6.49 d, P=0.02) were significantly less in the treatment group than those in the control group. The morbidity of infection and the morbidity of gastrointestinal disorders of the treatment group were statistically less than those of the control group (1.65% vs. 5.59%, P=0.00; 2.48% vs. 6.99%, P<0.001), and there was no statistical difference in mortality between the two groups (1.65% vs. 2.10%, P=0.12).
Conclusions The combined treatment with probiotics and lactulose can improve the postoperative inflammatory reaction, gastrointestinal function, and reduce the morbidity of infection.
Acute cerebral infarction is characterized by high incidence rate, high recurrence rate, high disability rate and multiple complications. Early evaluation and treatment of acute cerebral infarction is particularly important to improve the survival rate and prognosis of patients. As an easily available clinical laboratory indicator, blood routine test can reflect the pathological changes in the body to a certain extent. In recent years, many studies have shown that the indicators such as red cell volume distribution width, mean platelet volume, neutrophil to lymphocyte ratio and platelet to lymphocyte ratio in blood routine examination have important values in the onset, severity and prognosis of acute cerebral infarction. This article reviews the correlations of the above parameters and ratio parameters with acute cerebral infarction, in order to provide some reference and basis for clinical diagnosis, treatment and prognosis evaluation of acute cerebral infarction.
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.
ObjectiveTo explore the relation of preoperative red blood cell distribution width (RDW) with prognosis in esophageal cancer.MethodsThe PubMed, EMbase, Web of Science, Cochrane Library, VIP, Wanfang, CNKI and SinoMed databases were searched to identify potential studies assessing the correlation between preoperative RDW and prognosis of esophageal cancer patients from establishment of databases to February 2019. The endpoint events included the overall survival (OS), cancer-specific survival (CSS) and disease-free survival (DFS). The Stata 12.0 software was applied for the meta-analysis and the hazard ratio (HR) and 95% confidence interval (CI) were calculated.ResultsA total of 10 retrospective studies involving 4 260 esophageal cancer patients from China or Japan were included. The score of Newcastle-Ottawa scale (NOS) of the included studies was more than 6 points. The results demonstrated that elevated preoperative RDW was significantly associated with poor CSS (HR=1.50, 95% CI 1.14 to 1.99, P=0.004) and DFS (HR=1.45, 95% CI 1.14 to 1.85, P=0.002), while no significant association between preoperative RDW and OS in esophageal cancer was observed (HR=1.17, 95% CI 0.95 to 1.45, P=0.143). Subgroup analysis based on the pathology revealed that preoperative RDW had high prognostic value in esophageal squamous carcinoma (ESCC) (HR=1.37, 95% CI 1.05 to 1.77, P=0.018).ConclusionPreoperative RDW may be an independent prognostic factor for Chinese and Japanese esophageal cancer patients, especially for ESCC patients. However, more prospective studies with bigger sample sizes from other countries are still needed to verify our findings.
