RNA interacts with topoisomerase I to adjust DNA topology.

Topoisomerase I (TOP1) is an essential enzyme that relaxes DNA to prevent and dissipate torsional stress during transcription. However, the mechanisms underlying the regulation of TOP1 activity remain elusive. Using enhanced cross-linking and immunoprecipitation (eCLIP) and ultraviolet-cross-linked RNA immunoprecipitation followed by total RNA sequencing (UV-RIP-seq) in human colon cancer cells along with RNA electrophoretic mobility shift assays (EMSAs), biolayer interferometry (BLI), and in vitro RNA-binding assays, we identify TOP1 as an RNA-binding protein (RBP). We show that TOP1 directly binds RNA in vitro and in cells and that most RNAs bound by TOP1 are mRNAs. Using a TOP1 RNA-binding mutant and topoisomerase cleavage complex sequencing (TOP1cc-seq) to map TOP1 catalytic activity, we reveal that RNA opposes TOP1 activity as RNA polymerase II (RNAPII) commences transcription of active genes. We further demonstrate the inhibitory role of RNA in regulating TOP1 activity by employing DNA supercoiling assays and magnetic tweezers. These findings provide insight into the coordinated actions of RNA and TOP1 in regulating DNA topological stress intrinsic to RNAPII-dependent transcription.

Detection of Rat Hepatitis E Virus in Pigs, Spain, 2023.

We identified rat hepatitis E virus (HEV) RNA in farmed pigs from Spain. Our results indicate that pigs might be susceptible to rat HEV and could serve as viral intermediaries between rodents and humans. Europe should evaluate the prevalence of rat HEV in farmed pigs to assess the risk to public health.

Citizen silence: Missed opportunities in citizen science.

Citizen science is personal. Participation is contingent on the citizens' connection to a topic or to interpersonal relationships meaningful to them. But from the peer-reviewed literature, scientists appear to have an acquisitive data-centered relationship with citizens. This has spurred ethical and pragmatic criticisms of extractive relationships with citizen scientists. We suggest five practical steps to shift citizen-science research from extractive to relational, reorienting the research process and providing reciprocal benefits to researchers and citizen scientists. By virtue of their interests and experience within their local environments, citizen scientists have expertise that, if engaged, can improve research methods and product design decisions. To boost the value of scientific outputs to society and participants, citizen-science research teams should rethink how they engage and value volunteers.

Molecular detection of Enterocytozoon bieneusi in bats from Portugal.

Enterocytozoon bieneusi is a microsporidia commonly found in the gastrointestinal tract of humans and a wide range of other animals, constituting a major cause of microsporidiosis in humans. Although E. bieneusi has been detected in humans, domestic, and wild animals in Portugal, and its presence in bats has been linked to zoonotic characteristics, its occurrence in bats within the country has not been reported. In this study, we investigated the presence of E. bieneusi in 380 bat fecal samples collected in mainland Portugal through a nested PCR assay targeting the internal transcribed spacer region and the flanking small and large subunits of the ribosomal RNA. Enterocytozoon bieneusi was detected in one bat sample (i.e., 0.26%; Pipistrellus pipistrellus). Additionally, another sample tested positive for Enterocytozoon sp. Phylogenetic analysis of the obtained ITS sequence of E. bieneusi revealed clustering within the potentially zoonotic Group 1. This study represents the first report of E. bieneusi in a bat from Europe. Findings presented here contribute to an enhanced understanding of E. bieneusi epidemiology.

Enterocytozoon bieneusi is the most frequent cause of microsporidiosis in humans. In this study, E. bieneusi, belonging to a potentially zoonotic Group, was detected in 0.26% bat samples from Portugal, highlighting bats' potential role in transmitting this microsporidia to humans and other animals.

Barbed versus conventional suture in elective posterior spine surgery.

PURPOSE: Barbed sutures are tissue control devices that can reduce operating room time and costs. We analyzed the utility of barbed sutures in posterior spinal surgery in order to prove non-inferiority to conventional methods for wound closure. METHODS: A cohort of patients undergoing elective posterior spinal surgery in which barbed (prospective) versus conventional sutures (retrospective) were used was analyzed. The primary endpoint was the occurrence of wound healing complications or the need for surgical revision. Secondary endpoints included postoperative stay, readmission rate, and duration and cost of wound closure. RESULT: A total of 483 patients participated in the study, 183 in the Barbed group and 300 in the Conventional group. Wound dehiscence or seroma occurred in 3.8% and 2.7% of the Barbed and Conventional groups, respectively (p = 0.6588). Both superficial (1.6% versus 4.0%, P = 0.2378) and deep infections (2.7% versus 4.7%, p = 0.4124) occurred similarly in both groups. Overall, the rate of re-intervention due to wound healing problems was also similar (4.9% versus 5.3%, p = 0.9906), as well as, total median hospital stay, postoperative stay and 30-day re-admission rates. The average duration of wound closure (1.66 versus 4.16 min per level operated, p < 0.0001) strongly favored the Barbed group. The mean cost of wound closure per patient was higher in the Barbed group (43.23 € versus 22.67 €, p < 0.0001). CONCLUSIONS: In elective posterior spinal procedures, the use of barbed sutures significantly reduced the duration of wound closure. The wound healing process was not hindered and the added cost related to the suture material was small.

TET Enzymes and 5hmC Levels in Carcinogenesis and Progression of Breast Cancer: Potential Therapeutic Targets.

Breast Cancer (BC) was the most common female cancer in incidence and mortality worldwide in 2020. Similarly, BC was the top female cancer in the USA in 2022. Risk factors include earlier age at menarche, oral contraceptive use, hormone replacement therapy, high body mass index, and mutations in BRCA1/2 genes, among others. BC is classified into Luminal A, Luminal B, HER2-like, and Basal-like subtypes. These BC subtypes present differences in gene expression signatures, which can impact clinical behavior, treatment response, aggressiveness, metastasis, and survival of patients. Therefore, it is necessary to understand the epigenetic molecular mechanism of transcriptional regulation in BC, such as DNA demethylation. Ten-Eleven Translocation (TET) enzymes catalyze the oxidation of 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) on DNA, which in turn inhibits or promotes the gene expression. Interestingly, the expression of TET enzymes as well as the levels of the 5hmC epigenetic mark are altered in several types of human cancers, including BC. Several studies have demonstrated that TET enzymes and 5hmC play a key role in the regulation of gene expression in BC, directly (dependent or independent of DNA de-methylation) or indirectly (via interaction with other proteins such as transcription factors). In this review, we describe our recent understanding of the regulatory and physiological function of the TET enzymes, as well as their potential role as biomarkers in BC biology.

Fluoroscopy history, evolution, and technological advancements: A narrative review.

BACKGROUND: This narrative review provides a comprehensive overview of the history and evolution of fluoroscopy. The review examines the historical development of the technology, the technological advancements that have occurred over time, and the current applications of the technology in modern medicine. The review also identifies future considerations for the use of fluoroscopy in clinical practice. METHODS: Literature for this review was found by searching using multiple electronic databases on the City University of New York (CUNY) online library search engine. Relevant peer-reviewed articles and textbooks were included in the review with the exception of two articles; these non-peer-reviewed articles were included in the review because it contained relevant information on the history of fluoroscopy that was not available in any of the peer-reviewed articles that were found. The information found was analyzed by summarizing the key findings of each study; these findings were then synthesized and organized chronologically to identify the history and evolution of fluoroscopy throughout the years as well as the main personalities and events that contributed to its invention and developments. CONCLUSION: The fluoroscope has transformed from a simple handheld device to a streamlined and state of the art digital equipment. Throughout the years, numerous changes in its design and technology have occurred making the device more effective and safer for patients and operators. At the same time, since its early years, fluoroscopy plays an important role in the diagnosis and treatment of multiple pathological conditions, remaining an important imaging modality and tool in modern medicine. But what does the future hold for fluoroscopy? Will there continue to be more changes in its technology? What role will it continue to play in diagnostic imaging and modern medicine? These are all important questions for future consideration.

Exploring new roles for RNA-binding proteins in epigenetic and gene regulation.

A significant portion of the human proteome comprises RNA-binding proteins (RBPs) that play fundamental roles in numerous biological processes. In the last decade, there has been a staggering increase in RBP identification and classification, which has fueled interest in the evolving roles of RBPs and RBP-driven molecular mechanisms. Here, we focus on recent insights into RBP-dependent regulation of the epigenetic and transcriptional landscape. We describe advances in methodologies that define the RNA-protein interactome and machine-learning algorithms that are streamlining RBP discovery and predicting new RNA-binding regions. Finally, we present how RBP dysregulation leads to alterations in tumor-promoting gene expression and discuss the potential for targeting these RBPs for the development of new cancer therapeutics.

[Public policies and right to sexuality of the elderly in Chile]. / Public policies and right to sexuality of the elderly in Chile.

People over 65 years of age will constitute the majority of the world's population in the short term, but in precarious living conditions: more years in a worse condition of vulnerability and fragility. Societies and development models would not be prepared, generating high personal, family and collective costs. In Chile, fragility would be highly prevalent in this population, impacting the full development of their lives; with sexuality as one of the aspects that are invisible and little studied. This work makes a critical approach, based on the review and analysis of context, public policies and legislation in force in Chile, evidencing atomization and biomedical orientation of public policies, collaborating in the understanding of the relationship between fragility and sexuality in old people; and revealing pending training and research tasks for the generation of public policies for an active and healthy life.

Las personas mayores de 65 años constituirán la mayoría de la población mundial en corto plazo, pero en condiciones de vida precarias. Esto quiere decir que vivirán más años en peor condición de vulnerabilidad y fragilidad. Las sociedades y modelos de desarrollo no estarían preparados, generando altos costos personales, familiares y colectivos. En Chile la fragilidad sería altamente prevalente en esta población, impactando el desarrollo pleno de su vida. La sexualidad es uno de los aspectos que son invisibilizados y poco estudiados. Este trabajo realiza una aproximación crítica, a partir de la revisión y análisis de antecedentes de contexto, políticas públicas y legislación vigentes en Chile. En estos aspectos se evidencia atomización y orientación biomédica de las políticas públicas, colaborando en la comprensión de la relación fragilidad y sexualidad en personas mayores. Además, se revelan tareas de formación e investigación pendientes para la generación de políticas públicas para una vida activa y saludable.

Pressure fermentation to boost CO2-based poly(3-hydroxybutyrate) production using Cupriavidus necator.

CO2-based poly(3-hydroxybutyrate) (PHB) can be produced by the versatile bacterium Cupriavidus necator through chemolithoautotrophic fermentation, using a gas mixture consisting of CO2, H2, and O2. Despite offering a propitious route for carbon-neutral bioplastic manufacturing, its adoption is currently hampered by the wide explosive range of the required gas mixture, as well as the limited gas-to-liquid mass transfer rates. To address these challenges, pressure fermentation was applied as a robust and effective strategy, while ensuring safe operation by adhering to the limiting O2 concentration, utilizing state-of-the-art bioreactors. Consequently, exponential growth could be prolonged, boosting CO2-based PHB production from 10.8 g/L at 1.5 bar up to 29.6 g/L at 3 bar. The production gain closely aligns with the theoretical calculations, except for when the pressure was increased up to 4 bar. Overall, the demonstrated increase in PHB production underscores the potential of pressure fermentation to enhance aerobic gas fermentation.

Downstream-of-gene (DoG) transcripts contribute to an imbalance in the cancer cell transcriptome.

Downstream-of-gene (DoG) transcripts are an emerging class of noncoding RNAs. However, it remains largely unknown how DoG RNA production is regulated and whether alterations in DoG RNA signatures exist in major cancers. Here, through transcriptomic analyses of matched tumors and nonneoplastic tissues and cancer cell lines, we reveal a comprehensive catalog of DoG RNA signatures. Through separate lines of evidence, we support the biological importance of DoG RNAs in carcinogenesis. First, we show tissue-specific and stage-specific differential expression of DoG RNAs in tumors versus paired normal tissues with their respective host genes involved in tumor-promoting versus tumor-suppressor pathways. Second, we identify that differential DoG RNA expression is associated with poor patient survival. Third, we identify that DoG RNA induction is a consequence of treating colon cancer cells with the topoisomerase I (TOP1) poison camptothecin and following TOP1 depletion. Our results underlie the significance of DoG RNAs and TOP1-dependent regulation of DoG RNAs in diversifying and modulating the cancer transcriptome.

Correction: Social vulnerability during the COVID-19 pandemic in Peru.

[This corrects the article DOI: 10.1371/journal.pgph.0001330.].

Exercise training mode effects on myokine expression in healthy adults: A systematic review with meta-analysis.

BACKGROUND: The benefits of exercise are well known; however, many of the underlying molecular mechanisms are not fully understood. Skeletal muscle secretes myokines, which mediate muscle-organ crosstalk. Myokines regulate satellite-cell proliferation and migration, inflammatory cascade, insulin secretion, angiogenesis, fatty oxidation, and cancer suppression. To date, the effects of different exercise modes (namely, aerobic and resistance exercise) on myokine response remain to be elucidated. This is crucial considering the clinical implementation of exercise to enhance general health and wellbeing and as a medical treatment. METHODS: A systematic search was undertaken in PubMed, MEDLINE, CINAHL, Embase, SPORTDiscus, and Web of Science in April 2023. Eligible studies examining the effects of a single bout of exercise on interleukin15 (IL-15), irisin, secreted protein acidic and rich in cysteine (SPARC), oncostatin M (OSM), and decorin were included. A random-effects meta-analysis was also undertaken to quantify the magnitude of change. RESULTS: Sixty-two studies were included (n = 1193). Overall, exercise appeared to induce small to large increases in myokine expression, with effects observed immediately after to 60 min post-exercise, although these were mostly not statistically significant. Both aerobic and resistance exercise resulted in changes in myokine levels, without any significant difference between training modes, and with the magnitude of change differing across myokines. Myokine levels returned to baseline levels within 180 min to 24 h post-exercise. However, owing to potential sources of heterogeneity, most changes were not statistically significant, indicating that precise conclusions cannot be drawn. CONCLUSION: Knowledge is limited but expanding with respect to the impact of overall and specific effects of exercise on myokine expression at different time points in the systemic circulation. Further research is required to investigate the effects of different exercise modes at multiple time points on myokine response.

Exercise in cancer care for people with lung cancer: A narrative synthesis.

OBJECTIVES: Lung cancer is the second most common cancer diagnosed worldwide, resulting in significant physical and psychological consequences. In this narrative review, we explore the role of exercise as an adjunct therapy to counteract health issues experienced by people before, during and after treatment for lung cancer, and offer recommendations for exercise prescription and future research. DESIGN: Narrative cornerstone review. METHODS: A narrative review was conducted to explore the role of exercise in cancer care for people diagnosed with lung cancer. RESULTS: Improvements in fitness, strength and quality of life have been demonstrated in people with lung cancer following participation in exercise programmes before, during and post treatment. Whilst combined aerobic (50-100 % heart rate maximum) and resistance (50-85 % of 1 repetition maximum) training, 2-5 times per week across the cancer continuum is typically prescribed, few people with lung cancer currently access exercise services. 'Optimal' exercise prescription is unclear, although is likely individual-specific. The immediate priority is to identify a tolerable starting exercise dosage, with the side effects of lung cancer and its treatment on the respiratory system, particularly shortness of breath (dyspnoea), likely driving the initial maximum threshold for session mode, duration and intensity. To date, exercise safety for people with lung cancer has been poorly evaluated and reported - few trials report it, but those that do report small numbers of serious adverse events. CONCLUSIONS: Recommendations for health professionals prescribing exercise therapy to people with lung cancer are provided, with consideration of the strengths and limitations of the current evidence base.

Relationship between perceived physical literacy and obesity-related outcomes in adolescents: the EHDLA study.

Purpose: The aim of the present study was to examine the relationship between perceived physical literacy and obesity-related outcomes among adolescents from Spain. Methods: This is a secondary cross-sectional analysis including a total sample of 845 Spanish adolescents (55.3% girls) aged 12-17 years from the Valle de Ricote (Region of Murcia) from the Eating Healthy and Daily Life Activities (EHDLA) project. Physical literacy was evaluated using the Spanish Perceived Physical Literacy Instrument for adolescents (S-PPLI). Body mass index was computed by taking the participants' body weight in kilograms and dividing it by the square of their height in meters, and body mass index (z score) and overweight/obesity and obesity were computed by the World Health Organization age- and sex-specific thresholds. Waist circumference was measured using a constant tension tape. Moreover, the waist-to-height ratio was calculated, and therefore, abdominal obesity was determined. Skinfold measurements were taken at the triceps and medial calf using calibrated steel calipers. Results: In general, the overall trend was downward (i.e., the higher the PPLI score the lower the obesity-related indicators), with the approximate significance of smooth terms being statistically significant for all models examined (p < 0.001). Adolescents with lower perceived physical literacy (PPL) showed the highest estimated marginal means of body mass index, body mass index z score, waist circumference, waist-to-height ratio, and skinfold (triceps and calf) and predictive probabilities of having excess weight, obesity, and abdominal obesity, while their counterparts with high PPL had the lowest. In addition, significant differences were observed for all the obesity-related indications between adolescents with low PPL and those with medium PPL (p-adjusted < 0.05 for all indicators), as well as with those with high PPL (p-adjusted < 0.05 for all indicators). Moreover, these significant differences were also shown for most indicators between adolescents with medium PPL and those with high PPL (except for obesity). Conclusion: Physical literacy could play a crucial role in maintaining more desirable obesity-related outcomes in adolescents. Adolescents with high perceived physical literacy showed lower obesity-related indicators (i.e., body mass index, body mass index z score, waist circumference, waist-to-height ratio, skinfolds), as well as a lower probability of having excess weight, obesity, and abdominal obesity.

Exploring the link between perceived physical literacy and academic performance outcomes: insights from the EHDLA study.

Objective: The aim of this study was to verify the relationship between perceived physical literacy (PPL) and academic performance outcomes among Spanish adolescents aged 12-17 years. Methods: This cross-sectional study is a secondary examination utilizing data derived from the Eating Healthy and Daily Life Activities (EHDLA) project. The Spanish Perceived Physical Literacy Instrument for Adolescents (S-PPLI) was used to evaluate the PPL of the participants. To determine academic performance, the numerical grades for each subject were added together and then divided by the total number of subjects. Results: Overall, a positive trend in the association between S-PPLI scores and academic performance was observed. We identified two significant ranges within the S-PPLI scores. First, there was a significant range between 9 and 33 points on the S-PPLI, indicating an inverse association with academic performance. Second, another significant range was observed at scores of 34 points or higher on the S-PPLI, suggesting a positive association with academic performance. Participants with low PPL had the lowest academic performance (mean = 6.4; bias-corrected and accelerated (BCa) bootstrapped 95% confidence interval (CI): 6.2-6.6). Conversely, those adolescents with high PPL had the highest academic performance (mean = 6.9; BCa bootstrapped 95% CI: 6.6-7.1). Significant differences were found between low PPL and medium PPL (p-adjusted = 0.031) and between low PPL and high PPL (p-adjusted = 0.031). Conclusions: Increased physical literacy could be a relevant factor for achieving greater academic performance in adolescents. This study has potential implications for physical education instructors, school leaders, and healthcare practitioners.

Antecedent Cardiac Arrest Status of Donation After Circulatory Determination of Death (DCDD) Kidney Donors and the Risk of Delayed Graft Function After Kidney Transplantation: A Cohort Study.

BACKGROUND: The number of donors from donation after circulatory determination of death (DCDD) has increased by at least 4-fold over the past decade. This study evaluated the association between the antecedent cardiac arrest status of controlled DCDD donors and the risk of delayed graft function (DGF). METHODS: Using data from the Australia and New Zealand Dialysis and Transplant, the associations between antecedent cardiac arrest status of DCDD donors before withdrawal of cardiorespiratory support, DGF, posttransplant estimated glomerular filtration rate (eGFR), and allograft loss were examined using adjusted logistic, linear mixed modeling, and cox regression, respectively. Among donors who experienced cardiac arrest, we evaluated the association between duration and unwitnessed status of arrest and DGF. RESULTS: A total of 1173 kidney transplant recipients received DCDD kidneys from 646 donors in Australia between 2014 and 2019. Of these, 335 DCDD had antecedent cardiac arrest. Compared with recipients of kidneys from donors without antecedent cardiac arrest, the adjusted odds ratio (95% confidence interval) for DGF was 0.85 (0.65-1.11) among those with kidneys from donors with cardiac arrest. There was no association between antecedent cardiac arrest and posttransplant eGFR or allograft loss. The duration of cardiac arrest and unwitnessed status were not associated with DGF. CONCLUSIONS: This focused analysis in an Australian population showed that the allograft outcomes were similar whether DCDD donors had experienced a prior cardiac arrest, with no associations between duration or unwitnessed status of arrest and risk of DGF. This study thus provides important reassurance to transplant programs and the patients they counsel, to accept kidneys from donors through the DCDD pathway irrespective of a prior cardiac arrest.

Efficacy and Safety of Calcifediol in Young Adults with Vitamin D Deficiency: A Phase I, Multicentre, Clinical Trial-POSCAL Study.

Vitamin D deficiency is highly prevalent, and recent evidence suggests a possible association between vitamin D deficiency and various health conditions. The aim of this study was to assess monthly calcifediol treatments for vitamin D deficiency (or biweekly, if the deficiency was severe) in a young adult population with no associated comorbidities. This multicentre phase I trial started with a four month open-label treatment phase (TP) that included 101 participants (65% women with mean age 29.8 years). Eighty-two percent of the subjects (79/96) achieved 25(OH)D levels within the target range (20-60 ng/mL) by the end of the TP, and they were subsequently randomised and subjected to a double-blind, placebo-controlled, five month follow-up phase (FP). At the end of the FP, 89% of participants maintained vitamin D levels of >20 ng/mL with calcifediol, versus 49% with placebo (p < 0.001). Subjects receiving monthly calcifediol during both phases (n = 32) maintained 25(OH)D levels >20 ng/mL, whereas those on the placebo during the FP (n = 38) exhibited deficiency levels of 25(OH)D by the end of the study. No clinically relevant changes in bone metabolism parameters or toxic 25(OH)D levels were observed, and no serious adverse events were reported throughout the study. Calcifediol is a safe and effective treatment for vitamin D deficiency in the young adult population, but long-term use may be required to sustain optimal 25(OH)D levels.

Calcium, Phosphate, and Vitamin D in Children and Adolescents with Chronic Diseases: A Cross-Sectional Study.

Chronic diseases may affect the nutritional status of children and adolescents. Calcium (Ca), phosphorus (P), and vitamin D (Vit-D) are crucial nutrients for their growth and development. Proper diagnosis and treatment are critical components of personalized and precision medicine. Hence, we conducted a cross-sectional and comparative study to evaluate Ca, P, and Vit-D levels in their non-skeletal functions and their association with health and nutritional biomarkers in children and adolescents with diverse chronic conditions. We performed anthropometric, body composition, clinical evaluation, biochemical analysis, and dietary survey methods. A total of 78 patients (1-19 years, 43 females, 42 children) took part in this study. Overall, 24, 30, and 24 participants were obese, undernourished, and eutrophic, respectively. Results found that 74% and 35% of individuals had deficient Vit-D and Ca intake, respectively. Most cases were normocalcemic. Results also found that 47% of the subjects had Vit-D deficiency (VDD), 37% were insufficient, and 37% had hypophosphatemia. Of the 46% and 31% of patients with VDD and insufficient levels, 19% and 11% were hypophosphatemic, respectively. Calcium, P, and Vit-D levels were associated with anthropometric parameters, body mass index, body composition, physical activity, diet, growth hormones, and the immune, liver, and kidney systems. These results show the coincident risk of altered Ca, P, and Vit-D metabolism in children and adolescents with chronic diseases.

Predicting histological grade in symptomatic meningioma by an objective estimation of the tumoral surface irregularity.

INTRODUCTION: Predicting the histopathologic grade of meningioma is relevant because local recurrence is significantly greater in WHO grade II-III compared to WHO grade I tumours, which would ideally benefit from a more aggressive surgical strategy. It has been suggested that higher WHO grade tumours are more irregularly-shaped. However, irregularity is a subjective and observer-dependent feature. In this study, the tumour surface irregularity of a large series of meningiomas, measured upon preoperative MRI, is quantified and correlated with the WHO grade. METHODS: Unicentric retrospective observational study of a cohort of symptomatic meningiomas surgically removed in the time period between January 2015 and December 2022. Using specific segmentation software, the Surface Factor (SF) was calculated for each meningioma. SF is an objective parameter that compares the surface of a sphere (minimum surface area for a given volume) with the same volume of the tumour against the actual surface of the tumour. This ratio varies from 0 to 1, being 1 the maximum sphericity. Since irregularly-shaped meningiomas present proportionally greater surface area, the SF tends to decrease as irregularity increases. SF was correlated with WHO grade and its predictive power was estimated with ROC curve analysis. RESULTS: A total of 176 patients (64.7% females) were included in the study; 120 WHO grade I (71.9%), 43 WHO grade II (25.7%) and 4 WHO grade III (2.4%). A statistically significant difference was found between the mean SF of WHO grade I and WHO grade II-III tumours (0.8651 ±â€¯0.049 versus 0.7081 ±â€¯0.105, p < 0.0001). Globally, the SF correctly classified more than 90% of cases (area under ROC curve 0.940) with 93.3% sensibility and 80.9% specificity. A cutoff value of 0.79 yielded the maximum precision, with positive and negative predictive powers of 82.6% and 92.6%, respectively. Multivariate analysis yielded SF as an independent prognostic factor of WHO grade. CONCLUSION: The Surface Factor is an objective and quantitative parameter that helps to identify aggressive meningiomas preoperatively. A cutoff value of 0.79 allowed differentiation between WHO grade I and WHO grade II-III with high precision.