Objective To learn the distribution pattern and worldwide research tendency of vitrectomy literatures. Methods Articles were searched from American Institute of Scientific Information (ISI) online database of web of science (WOS) database as a data source, to analyze the age distribution, national and regional, funding agency and citation of the vitrectomy literatures included during the year of 1971 -2011. The analysis software BibExcel and SPSS 19.0 were used to cluster highfrequency of them. Results Totally 8540 literatures were included, the numbers of them were gradually increased since 1971, significantly after 1991. The literatures were mainly in English, the literatures of our country capacity ranked 6th; funded institutions in all article, the National Natural Science Foundation of China ranked No. 5. Citation gradually increased since 1991, increased significantly after 2004. There were 50 highfrequency subjects, and hot topics were clustered into 6 categories which including vitrectomy for diseases of macula lutea, new techniques and complication of vitrectomy, medical treatment and surgical therapy of diabetic retinopathy, cataract, vitrectomy for endophthalmitis caused by intraocular injection and eye injury. Conclusions There is a growing trend on the research of vitrectomy. The hot topics include vitrectomy for diseases of macula lutea, new techniques and complication of vitrectomy. It may provide references for the scholars in scientific research and clinical studies.
Objective To analyze and reveal the domestic and abroad studies on polypoidal choroidal vasculopathy (PCV) by bibliometric. Methods Foreign articles were searched from American Institute of Scientific Information online database of web of science (WOS) database, Chinese articles were searched from China National Knowledge Infrastructure (CNKI) database. The age distribution, national and regional, funding agency and citation of the PCV literatures published before December 31 2012 were analyzed by software Bibexcel and SPSS 17.0. Results Totally 696 literatures were analyzed, including 440 foreign literatures and 256 Chinese literatures. The numbers of foreign literatures were gradually increased since 2000, significantly after 2007, reached the maximum at 2011. The literatures were mainly in English, the number of the literatures of China ranked 4th of all countries. The National Natural Science Foundation of China ranked No.5 of funding agency. Citations gradually increased since 2000, increased significantly after 2008; there were 30 highfrequency subjects, and hot topics were clustered into 5 categories: treatment of PCV, genetics studies of PCV, detection, diagnosis and epidemiology of PCV, relationships between PCV and macular degeneration, related cytokine of PCV. Chinese literatures increased since 2000, significantly after 2006, and reached the maximum at 2010; there were 15 literatures supported by National Natural Science Foundation of China; Citation of Chinese literatures gradually increased since 2001, and reached the maximum at 2012. There were 30 highfrequency subjects, and hot topics were clustered into 5 categories: genetics and cytokine studies of PCV, detection and diagnosis of PCV, treatment of PCV, PCV and macular diseases, PCV and vitreous hemorrhage. Conclusions Literatures of PCV were gradually increased since 2000, abroad and domestic literatures of PCV reached maximum at 2011 and 2010 respectively. The abroad research of PCV focuses on 5 categories: treatment of PCV, genetics studies of PCV, detection, diagnosis and epidemiology of PCV, relationships between PCV and macular degeneration, related cytokine of PCV. The domestic research focuses on genetics and cytokine studies of PCV, detection and diagnosis of PCV, treatment of PCV, PCV and macular diseases, PCV and vitreous hemorrhage.
ObjectiveTo analyze the current situation and international research focuses on the study of medical device risk management. MethodsTo retrieve medical device risk management literature information cited from 2002 to 2011 in PubMed such as high-frequency MeSH; analyze current situation and research focuses of medical device risk management by using bibliometrics, bibliographic item co-occurrence matrix builder (BICOMB), and graphical clustering toolkit (gCluto) for quantitative analysis, high-frequency MeSH term papers cluster visualization analysis. ResultsA total of 7 073 published studies were retrieved, basically suggesting a gradually increasing trend of the number of published papers. The top 3 numbers of first authors' papers referred to three countries: the United States, Britain and Germany, while China ranked twelfth. The top 3 numbers of journal articles referred to the United States, Britain and Holland, while China ranked twenty-second. Twenty journals published more than 50 papers, and all these journals were clinical journals. Thirty-three authors published no less than 5 papers, with the maximum of 18 articles. Totally, there were 124 highfrequency MeSHs. The high-frequency MeSHs were classified into 6 categories by using double cluster analysis: kinds 0 to 4 included risk report, risk analysis, risk assessment and methodology of heart valve prosthesis, coronary stents, peripheral vascular stents, implantable defibrillators and other life support device, surgical repair surgical flaps and minimal invasion surgical device such as laparoscopy; kind 5 focused on safety management, risk control, organization and implementation and other related research based on prevention and control of medical device adverse reaction, medical errors, occupation exposure, and equipment failure. ConclusionThe analysis on international literature on medical device risk management basically shows a gradually increasing trend; most studies published in the clinical medicine journals; research focus on risk assessment, safety management and quality improvement in the application such as angioplasty, artificial prosthesis replacement, plastic surgery, minimally invasive surgery and critical care medicine, and radiology diagnosis and treatment; implantable, life-supported invasive and radiological devices as the main research subject; and characteristics include closely combination between medical device risk management and the application of safe and effective, quality improvement systems for clinical diagnosis and treatment.
Objective To investigate the phenotyping of COPD by cluster analysis and evaluate the value of this method.Methods 168 COPD patients were enrolled from Beijing Tongren Hospital. Demographic and clinical data, such as, sex, age, body mass index ( BMI) , smoking index, course of disease,exacerbation rate, and comorbidities were collected. Pulmonary function test, emphysema scoring by HRCT,dyspnea by MMRC score, COPD assessment test ( CAT) score, six-minute walk test were performed for each patient during the stable stage. Cluster analysis was conducted using SPSS 13. 0. Results According to the GOLD criteria,5, 75, 75, and 13 patients were classified into GOLD stage 1, 2, 3, and 4, respectively. There was no difference among different stages in sex distribution, BMI, smoking index, hypertension, and cerebral infarction incidence( P gt; 0. 05) , but the differences in age, disease course, dyspnea score, six-minute walk distance, BODE score, CAT score, coronary heart disease, exacerbation rate, and HRCT emphysema visual score were significant( P lt;0. 05) . By cluster analysis,168 patients were finally classified into three groups:younger/mild, older/ severe, and older/moderate. The patients with the same GOLD stage appeared indifferent clusters and the patients belonging to different GOLD stages could be in the same cluster. There were significant differences among three groups in age, BMI, exacerbation rate, dyspnea score, CAT score, and comorbidities. The result showed that HRCT emphysema visual score was also an important index todifferentiate clusters, suggesting that emphysema was an important phenotype of COPD. Conclusions Cluster analysis can classify homogeneous subjects into the same cluster, and heterogeneous subjects into different clusters. The results suggest that COPD phenotyping by cluster analysis is clinically useful and significant.
Cluster randomized trial (CRT) is one of the most common design for complex intervention. This paper mainly introduced:the definition of CRT, two designs of CRT including the completely randomization and the restricted randomization (such as stratified randomization and matching randomization), and the statistical analysis methods (such as the general statistical analysis and mixed effect model/multi-level model). This paper also introduced how to estimate the sample size of a CRT, how to report a CRT, and how to apply it into a clinical or community study.
Objective To investigate the hot topics of research on evidence-based medicine in 2002. Method To search MEDLINE for papers on evidence-based medicine published in 2002, identify high-frequency subject headings related to research on evidence-based medicine, and cluster the high-frequency subject headings according to rates they appeared in common papers. Results 545 papers, 1 554 subject headings, 30 high-frequency subject headings on evidence-based medicine, and nine clustering categories of high-frequency subject headings were identified through search. Conclusions Both high-frequency subject headings and their clustering categories suggested that “evidence-based practice guidelines and their innovation”, “evidence-based health research and health policy”, “methodology on systematic reviews and randomized clinical trials”, “method of evidence-based decision making and its application in various subjects”, were the hot topics of evidence-based medicine. They provided useful references for Chinese medical professionals to practice evidence-based medicine.
ObjectiveTo observe the effects of cluster therapy combined with anisodamine, dexamethasone and ambroxol on arterial blood gas, inflammatory cytokines and pulmonary pathological changes by making an early (<48 h) primary blast lung injury model in rats. MethodsEighty Wistar rats were randomly divided into six groups, ie. a control group (n=5), an injury group (n=15), an ambroxol treatment group (n=15), a dexamethasone treatment group, a scopolamine treatment group (n=15), a combination of ambroxol, dexamethasone and anisodamine group (n=15). The treatment groups were injected intraperitoneally with ambroxol 46.7 mg/kg (three times a day) or (and) dexamethasone at 5 mg·kg–1·d–1 or (and) anisodamine at a dose of 3.33 mg/kg (three times a day). The rats in the injury group were injected intraperitoneally with an equal volume of normal saline. Respiratory rate and weight change were observed before and after injury. Five rats were sacrificed at 6 hours, 24 hours and 48 hours after injury in each experimental group. Arterial blood gas analysis, Yelverton pathological score, lung tissue wet/dry weight ratio, serum tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were measured. The lung histopathology was observed. ResultsAfter lung blast injury, the rats in the injury group showed progressive respiratory acidosis, and hypoxemia increased with the increase of IL-6 and TNF-α in a time-dependent manner. The PaO2 decreased in the groups with ambroxol, dexamethasone and anisodamine alone or in combination with anisodamine, and the contents of serum IL-6 and TNF-α decreased. Pathological edema and inflammatory infiltration of lung tissue were alleviated significantly. ConclusionsAfter treatment with dexamethasone, anisodamine and ambroxol after lung blast injury, blood gas analysis is improved, inflammatory factor level is decreased and lung injury is alleviated, indicating that the three drugs can treat lung detonation injury in rats. The cluster therapy is superior to the single drug therapy.
ObjectiveWhen using multi-center data to construct clinical prediction models, the independence assumption of data will be violated, and there is an obvious clustering effect among research objects. In order to fully consider the clustering effect, this study intends to compare the model performance of the random intercept logistic regression model (RI) and the fixed effects model (FEM) considering the clustering effect with the standard logistic regression model (SLR) and the random forest algorithm (RF) without considering the clustering effect under different scenarios. MethodsIn the process of forecasting model establishment, the prediction performance of different models at the center level was simulated when there were different degrees of clustering effects, including the difference of discrimination and calibration in different scenarios, and the change trend of this difference at different event rates was compared. ResultsAt the center level, different models, except RF, showed little difference in the discrimination of different scenarios under the clustering effect, and the mean of their C-index changed very little. When using multi-center highly clustered data for forecasting, the marginal forecasts (M.RI, SLR and RF) had calibrated intercepts slightly less than 0 compared with the conditional forecasts, which overestimated the average probability of prediction. RF performed well in intercept calibration under the condition of multi-center and large samples, which also reflected the advantage of machine learning algorithm for processing large sample data. When there were few multiple patients in the center, the FEM made conditional predictions, the calibrated intercept was greater than 0, and the predicted mean probability was underestimated. In addition, when the multi-center large sample data were used to develop the prediction model, the slopes of the three conditional forecasts (FEM, A.RI, C.RI) were well calibrated, while the calibrated slopes of the marginal forecasts (M.RI and SLR) were greater than 1, which led to the problem of underfitting, and the underfitting problem became more prominent with the increase in the central aggregation effect. In particular, when there were few centers and few patients, overfitting of the data could mask the difference in calibration performance between marginal and conditional forecasts. Finally, the lower the event rate the central clustering effect at the central level had a more pronounced impact on the forecasting performance of the different models. ConclusionThe highly clustered multi-center data are used to construct the model and apply it to the prediction in a specific environment. RI and FEM can be selected for conditional prediction when the number of centers is small or the difference between centers is large due to different incidence rates. When the number of hearts is large and the sample size is large, RI can be selected for conditional prediction or RF for edge prediction.
ObjectiveTo investigate the gene expression spectrum of retina and optic nerve after partial injury of optic nerve.MethodsSixty SD rats were randomly divided into 4 groups. The optic nerves of the right eyes were clipped for 6 seconds with a pair of crossaction forceps. The retinae and optic nerves in the operation eye and contralateral sham operation eye were removed 3, 7, 14, and 21 days after the injury to detect gene expression patterns with high-density DNA microarrays.ResultsChanges of a mass of gene expressions were found after the optic nerve injury, and the positive rate of gene expression was 2.35%, 6.48%, 3.82% and 4.09% after 3, 7, 14, 21 days, respectively, and the total positive rate was 11.77%. The functions of positive expression of the gene involved cell survival, cytoskeleton, extracellular matrix and cell adhesion, free radicals and oxidative damage, energy and metabolism, inflammation, neurotransmission and ion transport, signal transduction, structural protein, transcription and translation. Up-or down-regulation of repaired genes was the main part of the changes of gene expression, while the alteredexpression destroy genes was the minor part in the whole gene expression spectrum, in which the up- and down-regulation of expression of repaired genes accounted for 13.98% and 24.73% respectively 7 days after the injury, and the downregulation of expression of repaired genes accounted for 17.20% 14 days after the injury.ConclusionsA mass of gene expression changes occurs after the optic nerve injury, and the comprehensive view on the gene expression pattern following the optic nerve injury is crucial to discover the mechanism of post-injury reaction and regeneration.(Chin J Ocul Fundus Dis, 2005,21:163-166)
ObjectiveTo explore the preventive role of maintaining constant pressure of the endotracheal catheter cuff on ventilator-associated pneumonia (VAP). MethodsFrom January to December 2015, 96 patients of type Ⅱ respiratory failure were selected as the trial group who underwent intubation and mechanical ventilation more than 48 hours in the Intensive Care Unit (ICU). We used pressure gauges to measure the endotracheal catheter cuff pressure regularly and maintained a constant pressure in addition to the application of artificial airway cluster management. We recorded the initial pressure value which was estimated by pinching with finger and set initial pressure to 30 cm H2O (1 cm H2O=0.098 kPa). We measured endotracheal catheter cuff pressure and recorded it during different intervals. We reviewed 88 patients with the same disease as the control group who only accepted artificial airway cluster management between January and December 2014. Mechanical ventilation time, VAP occurrence time, ICU admission time, the incidence of VAP were recorded and analyzed for both the two groups of patients. ResultsIn the trial group, the initial pressure of endotracheal catheter cuff which was estimated by pinching with finger showed that only 11.46% of pressure was between 25 and 30 cm H2O and 82.29% of the pressure was higher than 30 cm H2O. We collected endotracheal catheter cuff pressure values during different interval time by using pressure gauges to maintain a constant management. The ratio at the pressure between 25 and 30 cm H2O was respectively 41.32%, 43.75%, 64.20%, 76.54%, 91.13%, and 91.85%. ICU admission time, mechanical ventilation time in patients of the trial group decreased more, compared with the control group, and the differences were statistically significant (t=4.171, P<0.001; t=4.061, P<0.001). The VAP occurrence time in patients of the trial group was later than the control group (t=2.247, P<0.001). ConclusionThe endotracheal catheter cuff pressure estimated by pinching with finger has errors. We recommend using pressure gauges to detect pressure every four hours, which utilizes minimal time to maintain effective pressure. The method of artificial airway of cluster management combined with the pattern of maintaining constant endotracheal catheter cuff pressure can shorten ICU admission time, mechanical ventilation time and delay the occurrence of VAP.