关键词： Phasic venous flow   Phasicity   Venous flow  

摘要： Background: Phasic venous flow variation with respiration is surrounded by controversy and not well understood. The current concept assigns a major role to the "abdominal pump." According to this model, inspiratory increases in abdominal pressure compress the vena cava, increasing its internal venous pressure and propelling blood upstream. Some have assigned a secondary role to the "thoracic pump," with the negative intrapleural pressure aiding blood flow toward the heart. The aim of the present study was to examine the phasic changes in flow, pressure, and volume in the central veins and named tributaries. Methods: Caliber area changes were measured using intravascular ultrasonography in 37 patients undergoing iliac vein stenting. The pressure was measured in 48 patients using transducer tip catheters with electronic zero calibration. Duplex ultrasound flow in the head and neck and truncal and limb veins during inspiration and expiration was measured in 15 normal volunteers. Results: The caliber of the abdominal inferior vena cava had increased by 32% and its lateral pressure had decreased significantly during inspiration. Intravenous pressure in the central veins of the chest and right atrium was positive at 6 to 14 mm Hg. Negative pressures were rarely seen and then only transiently. The internal jugular vein displayed little phasic variation. The upper limb veins displayed weak inspiratory phasicity. Phase polarity was reversed in the lower limbs, with near flow stoppage during inspiration. Conclusions: These observations conflict with the current notions of venous flow phasicity, which are based on push-pull pressure changes in the abdominal and thoracic veins. The paradoxical inspiratory inferior vena cava caliber increase probably explains the concurrent pressure decrease. Sustained negative pressures in the thoracic central veins and right atrium did not occur. We have proposed an alternate hypothesis for venous flow phasicity based on alternate stretching a

摘要： The Core EPAs for Entering Residency Pilot project aimed to test the feasibility of implementing 13 entrustable professional activities (EPAs) at 10 U.S. medical schools and to gauge whether the use of the Core EPAs could improve graduates' performance early in residency. In this manuscript, the authors (members of the pilot institutions and Association of American Medical Colleges staff supporting the project evaluation) describe the schools' capacity to collect multimodal evidence about their students' performance in each of the Core EPAs and the ability of faculty committees to use those data to make decisions regarding learners' readiness for entrustment. In reviewing data for each of the Core EPAs, the authors reflected on how each activity performed as an EPA informed by how well it could be assessed and entrusted. For EPAs that did not perform well, the authors examined whether there are underlying practical and/or theoretical issues limiting its utility as a measure of student performance in medical school.

摘要： Objective Dietary supplements and alternative therapies are commercialized as a panacea for obesity/weight gain as a result of the minimal regulatory requirements in demonstrating efficacy. These products may indirectly undermine the value of guideline-driven obesity treatments. Included in this study is a systematic review of the literature of purported dietary supplements and alternative therapies for weight loss. Methods A systematic review was conducted to evaluate the efficacy of dietary supplements and alternative therapies for weight loss in participants aged >= 18 years. Searches of Medline (PubMed), Cochrane Library, Web of Science, CINAHL, and Embase (Ovid) were conducted. Risk of bias and results were summarized qualitatively. Results Of the 20,504 citations retrieved in the database search, 1,743 full-text articles were reviewed, 315 of which were randomized controlled trials evaluating the efficacy of 14 purported dietary supplements, therapies, or a combination thereof. Risk of bias and sufficiency of data varied widely. Few studies (n = 52 [16.5%]) were classified as low risk and sufficient to support efficacy. Of these, only 16 (31%) noted significant pre/post intergroup differences in weight (range: 0.3-4.93 kg). Conclusions Dietary supplements and alternative therapies for weight loss have a limited high-quality evidence base of efficacy. Practitioners and patients should be aware of the scientific evidence of claims before recommending use.

关键词： Bone   DNA typing   Forensic genetics   Human identification   Short tandem repeat  

摘要： In forensic genetics, the analysis of postmortem bones is one of the most challenging due to the low quantity of degraded endogenous DNA. The most widely used approach for sample preparation, in those cases, is pulverizing the bone. However, processing pulverized bone is extremely delicate, requiring strict laboratory conditions and operating procedures. In fact, several recent publications have focused on non-powder approaches. The objectives of this study were, thus, to validate a non-powder protocol for DNA extraction from forensic bones and an alternative pretreatment, large fragment demineralization (LFD). Thirty human femurs and tibiae received by the Legal Medicine Institute of Brescia, Italy, were included in the study. Bone powder and one transversal section of the diaphysis were sampled from each bone. DNA extraction from the powder was carried out using PrepFiler BTA (BTA), while the transversal section was submitted to the alternative demineralizing pretreatment (LFD) followed by DNA extraction using the QIAamp DNA Investigator. DNA extracts were assessed for human DNA quantity and degradation by means of a validated in-house qPCR assay and amplified with commercial kits. Inhibition assessment was carried out through Quality Sensor analysis using 24plex QS Kit. The differences in quantity, quality of human DNA, and number of alleles detected between both methods were comparable and not statistically significant. We propose the use of the LFD protocol as a complementary approach capable of confirming the genotypes or detect alleles not observed using BTA, without the need for pulverization.

关键词： Impact evaluation   Irrigation technology adoption   Sample selection   Stochastic frontier   Technical efficiency  

摘要： The interest in promoting food and water security through development projects has led to the need to evaluate the impact of these projects. This study evaluates the impact from transitioning to a modern irrigation technology. Deciding to adopt or not an alternative irrigation technology (sprinklers) is not necessarily a random determination. Therefore, selection bias can be present and this can lead to biased estimates. In this study, we apply methodological specifications to correct for self-selectivity biases. Then, we measure and compare the technical efficiency scores from adopters and non-adopters. The empirical application uses data covering 56 small-scale greenhouse farms in Crete (Greece) for the cropping years 2009-2013. The results reveal that the average technical efficiency for farmers who adopted sprinkler irrigation is lower than the group of non-adopters, when the presence of selectivity bias cannot be rejected. This implies that either the farmers need more time to incorporate the know-how of the newly acquired technology or they become less motivated after the adoption. Consequently, agricultural water saving technologies need to be promoted in combination with support to the farmers, so they can cope with the lower performance in the first years after adoption.

摘要： The COVID-19 pandemic of 2020 exposed the reactive nature of the medical education community in response to a disruption that, at one time, may have seemed preposterous. In this article, the author reflected on the impact of an unpredictable plight on a system of medical education that (1) is continuous but doesn't function as a continuum and (2) requires adaptation but is steeped in a fixed mindset and structure that resists change. As a result, innovations which were previously considered impossible, such as time variable education and training, were forced into being. Inspired by the changes brought about by the pandemic, the ensuing decade is explored through a lens of possible futures to envision a path forward based on resilience rather than reactivity.

摘要： Scholars are increasingly aware that studies-across many disciplines-cannot be replicated by independent researchers. Here, the authors describe how medical education research may be vulnerable to this "replication crisis," explain how researchers can act together to reduce risks, and discuss the positive steps that can increase confidence in research findings. Medical education research contributes to policy and influences practitioner behavior. Findings that cannot be replicated suggest that the original research was not credible. This risk raises the possibility that unhelpful or even harmful changes to medical education have been implemented as a result of research that appeared defensible but was not. By considering these risk factors, researchers can increase the likelihood that studies are generating credible results. The authors discuss and provide examples of 6 factors that may endanger the replicability of medical education research: (1) small sample sizes, (2) small effect sizes, (3) exploratory designs, (4) flexibility in design choices, analysis strategy, and outcome measures, (5) conflicts of interest, and (6) very active fields with many competing research teams. Importantly, medical education researchers can adopt techniques used successfully elsewhere to improve the rigor of their investigations. Researchers can improve their work through better planning in the development stage, carefully considering design choices, and using sensible data analysis. The wider medical education community can help by encouraging higher levels of collaboration among medical educators, by routinely evaluating existing educational innovations, and by raising the prestige of replication and collaborative medical education research. Medical education journals should adopt new approaches to publishing. As medical education research improves, so too will the quality of medical education and patient care.

关键词： 5-Fluorouracil   anal cancer   anus   capecitabine   cisplatin   DPYD   fluoropyrimidines   mitomycin   pharmacogenetics   radiation   TYMS  

摘要： Background: 5-fluorouracil (5-FU) and mitomycin-C (MMC) with radiotherapy (RT) remain an established treatment for patients with anal cancer (AC). Genetic mutations in two major metabolizing enzymes for 5-FU;dihydropyrimidine dehydrogenase (DPYD and thymidylate synthetase (TYMS), have been associated with clinical response and toxicity. However, their place in the treatment of AC remains undetermined. Methods: We retrospectively reviewed 21 patients with AC, including T2-4, N0-1, M0 or T1-4, N2-3, and M0 treated between 2012 and 2018. All patients were treated with 5-FU 1,000 mg/m(2)/day via continuous intravenous (IV) infusion 1-4 and 29-32, MMC 10 mg/m(2) IV bolus days 1 and 29 plus RT. Patients who developed > 3 grade toxicities were tested for the DPYD and TYMS genes. Treatment was either modified with reduced doses or changed to MMC 10 mg/m(2) day 1 and 29 with cisplatin 25 mg/m(2)/week plus RT. Toxicities and responses were collected. Results: Six out of 21 patients who developed > 3 grade toxicities including pancytopenia, neutropenia, thrombocytopenia, mucositis, nausea, rash, and nephritis were found to have genetic mutations: TYMS 2RG/3RC (n = 2), 3RG/3RC (n = 1), 2R/2R (n = 2), TYMS 3 ' UTR del/Ins (n = 2), and DPYD c.2864A > T heterozygous (n = 1). Two patients received 5-FU at a 50% reduced dose on days 29-32;one patient refused to receive 5-FU (continued with MMC and RT);one patient received only radiation therapy due to persistent pancytopenia despite the use of growth factors;two patients received an alternative regimen consisting of MMC 10 mg/m(2) on day 29 with cisplatin (CDDP) 25 mg/m(2)/week plus RT;and two patients received cisplatin/MMC with RT from the beginning as they were prospectively detected to have TYMS abnormalities prior to dosing the chemotherapy. These patients tolerated treatment very well with only grade 2 toxicities. All the patients (4/4) on cisplatin/MMC achieved clinical complete response (cCR), while four patients (4/15) on 5

摘要： Rationale Guidelines recommend pre-/post-bronchodilator spirometry for diagnosing COPD, but resource constraints limit the availability of spirometry in primary care in low- and middle-income countries. Although spirometry is the diagnostic gold standard, we shall assess alternative tools for settings without spirometry. Methods A systematic literature review and meta-analysis was conducted, utilising Cochrane, CINAHL, Google Scholar, PubMed and Web of Science (search cut-off was May 01, 2020). Published studies comparing the accuracy of diagnostic tools for COPD with post-bronchodilator spirometry were considered. Studies without sensitivity/specificity data, without a separate validation sample and outside of primary care were excluded. Sensitivity, specificity and area under the curve (AUC) were assessed. Results Of 7578 studies, 24 were included (14635 participants). Hand devices yielded a larger AUC than questionnaires. The meta-analysis included 17 studies and the overall AUC of micro-spirometers (0.84, 95% CI 0.80-0.89) was larger when compared to the COPD population screener (COPD-PS) questionnaire (0.77, 95% CI 0.63-0.85) and the COPD diagnostic questionnaire (CDQ) (0.72, 95% CI 0.64-0.78). However, only the difference between micro-spirometers and the CDQ was significant. Conclusions The CDQ and the COPD-PS questionnaire were approximately equally accurate tools. Questionnaires ensured testing of symptomatic patients, but micro-spirometers were more accurate. A combination could increase accuracy but was not evaluated in the meta-analysis.