Background: Studies have recently examined the role of epigenetic mechanisms in preeclampsia pathophysiology. One commonly examined epigenetic process is DNA methylation. This heritable epigenetic marker is involved in many important cellular functions. The aim of this study was to establish the association between DNA methylation and preeclampsia and to critically appraise the roles of major study characteristics that can significantly impact the association between DNA methylation and preeclampsia. Main body: A systematic review was performed by searching PubMed, Web of Science, and EMBASE for original research articles published over time, until May 31, 2019 in English. Eligible studies compared DNA methylation levels in pregnant women with vs. without preeclampsia. Ninety articles were included. Epigenome-wide studies identified hundreds of differentially methylated places/regions in preeclamptic patients. Hypomethylation was the predominant finding in studies analyzing placental tissue (14/19), while hypermethylation was detected in three studies that analyzed maternal white blood cells (3/3). In candidate gene studies, methylation alterations for a number of genes were found to be associated with preeclampsia. A greater number of differentially methylated genes was found when analyzing more severe preeclampsia (70/82), compared to studies analyzing less severe preeclampsia vs. controls (13/27). A high degree of heterogeneity existed among the studies in terms of methodological study characteristics including design (study design, definition of preeclampsia, control group, sample size, confounders), implementation (biological sample, DNA methylation method, purification of DNA extraction, and validation of methylation), analysis (analytical method, batch effect, genotyping, and gene expression), and data presentation (methylation quantification measure, measure of variability, reporting). Based on the results of this review, we provide recommendations for study design and analytical approach for further studies. Conclusions: The findings from this review support the role of DNA methylation in the pathophysiology of preeclampsia. Establishing field-wide methodological and analytical standards may increase value and reduce waste, allowing researchers to gain additional insights into the role of DNA methylation in the pathophysiology of preeclampsia.

Background: The concept of flipped classrooms (FCs) is gaining attention in medical education as it aligns with the digital age’s demand for more interactive and accessible learning experiences. By shifting the delivery of instructional content outside of the classroom, an FC allows students to engage with materials at their own pace, thereby maximizing in-class time for discussions, problem-solving, and other active learning activities. Objective: This study aimed to conduct a comprehensive meta-analysis to appraise the comparative effectiveness of FC instruction in contrast to traditional pedagogical modalities, with a particular focus on postepidemic analyses within specific subfields of medical education. Methods: The PubMed, Web of Science, and Scopus databases were systematically searched for studies comparing academic outcomes between the FC and traditional learning approaches in medical education. The primary outcome measures were knowledge assessment and students’ satisfaction. The standardized mean difference (SMD) was used as a measure of the overall effect, and subgroup analysis was performed according to the study design (randomized controlled trial [RCT] vs observational). The Cochran Q test and Baujat plots were used to estimate heterogeneity, coupled with I2. Highly influential studies were identified; sensitivity analyses and metaregression were performed. Results: In total, 141 studies were included in the systematic review; 127 (90.1%) studies with 21,171 participants were included in the meta-analysis of students’ knowledge assessment, of which 37 (29.1%) were RCTs. FCs had significantly better outcomes than the traditional method in knowledge test scores in both observational studies and RCTs (SMD 0.90, 95% CI 0.59-1.20, P<.001 and SMD 0.93, 95% CI 0.65-1.22, P<.001, respectively). There was substantial heterogeneity among included studies (I2=95.2%, τ2=1.614; P<.001). The funnel plot showed high asymmetry with significant small study effects (P<.001). However, the effect estimate remained robust to the exclusion of highly influential studies in the sensitivity analysis. In total, 27 (21.3%) studies with a total of 5842 participants reported students’ satisfaction. Higher student satisfaction scores for FCs were demonstrated in contrast to control groups (SMD 0.82, 95% CI 0.45-1.19; P<.001). There was substantial heterogeneity among the included studies (I2=97.8%, τ2=0.913; P<.001) but no evidence for publication bias, and no studies were found to be influential. Conclusions: The FC method is associated with better knowledge achievement and greater student satisfaction than the traditional approach in medical education, paving the way for its broader integration into medical school curricula. However, it is essential to consider various factors, such as the availability of resources, faculty readiness, and student preferences when implementing any new educational approach. This study holds promise for advancing medical education by exploring innovative teaching methodologies that leverage technology to enhance learning outcomes.

Although recent studies report on the benefits of blended learning in improving medical student education, there is still no empirical evidence on the relative effectiveness of blended over traditional learning approaches in medical statistics. We implemented blended along with on-site (i.e. face-to-face) learning to further assess the potential value of web-based learning in medical statistics. This was a prospective study conducted with third year medical undergraduate students attending the Faculty of Medicine, University of Belgrade, who passed (440 of 545) the final exam of the obligatory introductory statistics course during 2013–14. Student statistics achievements were stratified based on the two methods of education delivery: blended learning and on-site learning. Blended learning included a combination of face-to-face and distance learning methodologies integrated into a single course. Mean exam scores for the blended learning student group were higher than for the on-site student group for both final statistics score (89.36±6.60 vs. 86.06±8.48; p = 0.001) and knowledge test score (7.88±1.30 vs. 7.51±1.36; p = 0.023) with a medium effect size. There were no differences in sex or study duration between the groups. Current grade point average (GPA) was higher in the blended group. In a multivariable regression model, current GPA and knowledge test scores were associated with the final statistics score after adjusting for study duration and learning modality (p<0.001). This study provides empirical evidence to support educator decisions to implement different learning environments for teaching medical statistics to undergraduate medical students. Blended and on-site training formats led to similar knowledge acquisition; however, students with higher GPA preferred the technology assisted learning format. Implementation of blended learning approaches can be considered an attractive, cost-effective, and efficient alternative to traditional classroom training in medical statistics.

Objectives: Pre‐eclampsia (PE) is a pregnancy‐specific hypertensive disorder that has been associated with cardiovascular risk factors and vascular changes, such as acute atherosis in placental blood vessels, similar to early‐stage atherosclerosis. The objective of this study was to determine whether women with PE have increased atherosclerotic burden, as determined by the carotid intima–media thickness (CIMT), compared with women without PE.Methods: We conducted a systematic review and meta‐analysis of studies that reported CIMT, a non‐invasive, ultrasound‐based measure of subclinical atherosclerosis, in women who did vs those who did not have PE. Studies were eligible if they had been conducted during pregnancy or during the first decade postpartum, and if CIMT was measured in the common carotid artery. Studies published before 7 March 2016 were identified through PubMed, EMBASE and Web of Science. Two reviewers used predefined forms and protocols to evaluate independently the eligibility of studies based on titles and abstracts and to perform full‐text screening, data abstraction and quality assessment. Heterogeneity was assessed using the I² statistic. Standardized mean difference (SMD) was used as a measure of effect size.Results: Fourteen studies were included in the meta‐analysis. Seven studies were carried out during pregnancy complicated by PE, 10 were carried out up to 10 years postpartum and three included measurements obtained at both time periods. Women who had PE had significantly higher CIMT than did those who did not have PE, both at the time of diagnosis (SMD, 1.10 (95% CI, 0.73–1.48); P < 0.001) and in the first decade postpartum (SMD, 0.58 (95% CI, 0.36–0.79); P < 0.001).Conclusions: Atherosclerotic load is present at the time of PE and may be a mechanism associated with the disease. Measurement of CIMT may offer an opportunity for the early identification of premenopausal women with atherosclerotic burden after a PE pregnancy. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.RESUMENObjetivos: La preeclampsia (PE) es un trastorno hipertensivo específico del embarazo que ha sido asociada con factores de riesgo cardiovascular y cambios vasculares, tales como aterosis aguda en los vasos sanguíneos de la placenta, similares a las primeras etapas de la aterosclerosis. El objetivo de este estudio fue determinar si las mujeres con PE han aumentado la carga aterosclerótica, según lo determinado por el espesor del complejo íntima‐media de la arteria carótida (CIMT, por sus siglas en inglés), en comparación con las mujeres sin PE.Métodos: Se realizó una revisión sistemática y un metaanálisis de estudios que reportaron el CIMT, una medida no invasiva de la aterosclerosis subclínica obtenida mediante ecografía, comparando mujeres con PE y mujeres sin ella. Solo se incluyeron estudios llevados a cabo durante el embarazo o durante la primera década después del parto, y en los que se midió el CIMT en la arteria carótida común. Se usaron las bases de datos de PubMed, EMBASE y Web of Science para identificar estudios publicados antes del 7 marzo de 2016. Dos revisores utilizaron formularios y protocolos preestablecidos para evaluar de forma independiente la elegibilidad de los estudios, a partir de los títulos y los resúmenes, y para realizar un cribado del texto completo, un resumen de los datos y una evaluación de calidad. La heterogeneidad se evaluó mediante el test estadístico I². Se usó la diferencia de medias estandarizada (SMD, por sus siglas en inglés) como una medida de la magnitud del efecto.Resultados: En el metaanálisis se incluyeron catorce estudios. Siete de los estudios se llevaron a cabo durante embarazos complicados por PE, 10 se realizaron hasta 10 años después del parto y tres incluyeron mediciones tomadas en ambos períodos. Las mujeres con PE tuvieron un CIMT significativamente mayor que aquellas que no la tenían, tanto en el momento del diagnóstico (SMD 1,10 (I 95%, 0,73‐1,48), P <0,001) como en la primera década después del parto (SMD 0,58 (IC 95%, 0,36‐0,79), P <0,001).Conclusiones: La carga aterosclerótica está presente en el momento de la PE y podría ser un mecanismo asociado con esta enfermedad. La medición del CIMT puede ofrecer una oportunidad para la identificación temprana de mujeres premenopáusicas con carga aterosclerótica después de un embarazo con PE.目的: 子痫前期(pre‐eclampsia,PE)是一种妊娠期特发的高血压疾病,与心血管危险因素和血管改变有关,如胎盘血管急性动脉粥样硬化,与早期动脉粥样硬化相似。本研究的目的是通过检测颈动脉内—中膜厚度(carotid intima–media thickness,CIMT),确定妊娠合并PE与无合并PE患者相比,动脉粥样硬化负担是否增加。方法: 我们对报道PE患者与无PE患者相比CIMT的研究进行系统综述和meta分析,CIMT为无创性、基于超声的亚临床动脉粥样硬化检测方法。纳入标准为:研究在妊娠期间或产后头10年进行并检测颈总动脉的CIMT。检索PubMed、EMBASE和Web of Science中发表的研究,时间截止至2016年3月7日。由两名人员根据预定的格式和方案,通过题目和摘要独立评估符合纳入标准的研究,并进行全文筛查、数据提取和质量评估。采用I²检验评估异质性。采用标准化均数差(SMD)检测效应量。结果: meta分析中纳入14项研究。7项研究在妊娠合并PE时进行,10项研究在产后10年进行,3项研究在两个时间段均进行了检测。PE患者与无合并PE患者相比,确诊时[SMD,1.10(95% CI,0.73~1.48);P<0.001]以及产后头10年[SMD,0.58(95% CI,0.36~0.79);P<0.001] CIMT均明显较高。结论: PE时存在动脉粥样硬化负担,它可能与疾病发病机制有关。通过检测CIMT,可以早期识别PE妊娠后存在动脉粥样硬化负担的绝经前女性。

Citations are an important, but often overlooked, part of every scientific paper. They allow the reader to trace the flow of evidence, serving as a gateway to relevant literature. Most scientists are aware of citations’ errors, but few appreciate the prevalence of these problems. The purpose of the present study was to examine how often frequently cited papers in biomedical scientific literature are cited inaccurately. The study included an active participation of the first authors of included papers; to first-hand verify the citations accuracy. Findings from feasibility study, where we reviewed 1540 articles containing 2526 citations of 14 most cited articles in which the authors were affiliated with the Faculty of Medicine University of Belgrade, were further evaluated for external confirmation in an independent verification set of articles. Verification set included 4912 citations identified in 2995 articles that cited 13 most cited articles published by authors affiliated with the Mayo Clinic Division of Nephrology and Hypertension. A citation was defined as being accurate if the cited article supported or was in accordance with the statement by citing authors. At least one inaccurate citation was found in 11 and 15% of articles in the feasibility study and verification set, respectively, suggesting that inaccurate citations are common in biomedical literature. The most common problem was the citation of nonexistent findings (38.4%), followed by an incorrect interpretation of findings (15.4%). One-fifth of inaccurate citations were due to chains of inaccurate citations. Based on these findings, several actions to reduce citation inaccuracies have been proposed.

Development of abdominal compartment syndrome (ACS) in patients with severe acute pancreatitis (SAP) has a strong impact on the course of disease. Number of patients with this complication increases during the years due more aggressive fluid resuscitation, much bigger proportion of patients who is treated conservatively or by minimal invasive approach, and efforts to delay open surgery. There have not been standard recommendations for a surgical or some other interventional treatment of patients who develop ACS during the SAP. The aim of DECOMPRESS study was to compare decompresive laparotomy with temporary abdominal closure and percutaneus puncture with placement of abdominal catheter in these patients.