Learning clinical reasoning: how virtual patient case format and prior knowledge interact.

INTRODUCTION: Clinical reasoning has been fostered with varying case formats including the use of virtual patients. Existing literature points to different conclusions regarding which format is most beneficial for learners with diverse levels of prior knowledge. We designed our study to better understand which case format affects clinical reasoning outcomes and cognitive load, dependent on medical students' prior knowledge. METHODS: Overall, 142 medical students (3 rd to 6 th year) were randomly assigned to either a whole case or serial cue case format. Participants worked on eight virtual patients in their respective case format. Outcomes included diagnostic accuracy, knowledge, and cognitive load. RESULTS: We found no effect of case format on strategic knowledge scores pre- vs post-test (whole case learning gain = 3, 95% CI. -.01 to .01, serial cue learning gain = 3, 95% CI. -.06 to .00 p = .50). In both case formats, students with high baseline knowledge (determined by median split on the pre-test in conceptual knowledge) benefitted from learning with virtual patients (learning gain in strategic knowledge = 5, 95% CI .03 to .09, p = .01) while students with low prior knowledge did not (learning gain = 0, 95%CI -.02 to .02). We found no difference in diagnostic accuracy between experimental conditions (difference = .44, 95% CI -.96 to .08, p = .22), but diagnostic accuracy was higher for students with high prior knowledge compared to those with low prior knowledge (difference = .8, 95% CI 0.31 to 1.35, p < .01). Students with low prior knowledge experienced higher extraneous cognitive load than students with high prior knowledge (multiple measurements, p < .01). CONCLUSIONS: The whole case and serial cue case formats alone did not affect students' knowledge gain or diagnostic accuracy. Students with lower knowledge experienced increased cognitive load and appear to have learned less from their interaction with virtual patients. Cognitive load should be taken into account when attempting to help students learn clinical reasoning with virtual patients, especially for students with lower knowledge.

Photochromic Indolyl Fulgimides as Chromo-pharmacophores Targeting Sirtuins.

Sirtuins are involved in epigenetic regulation, the pathogenesis of cancer, and several metabolic and neurodegenerative diseases. Despite being a promising drug target, only one small molecule passed class II clinical trials to date. Deriving a better mechanistic understanding is hence crucial to find new modulators. We previously reported on a series of dithienyl maleimides as photochromic tool compounds. However, their photochromic behavior was limited. To improve the interconversion and stability of both photoisomers, we replaced the dithienyl maleimide with a fulgimide as a photochromic core to result in biologically active compounds reversibly addressable with purple and orange light. We characterize the obtained compounds regarding their spectroscopic properties, their photostability, and binding characteristics toward sirtuins resulting in a fully remote-controllable Sirtuin modulator using visible light as the external stimulant.

Targeting P-selectin by gallium-68-labeled fucoidan positron emission tomography for noninvasive characterization of vulnerable plaques: correlation with in vivo 17.6T MRI.

OBJECTIVE: Nuclear imaging of active plaques still remains challenging. Advanced atherosclerotic plaques have a strong expression of P-selectin by the endothelium overlying active atherosclerotic plaques, but not on the endothelium overlying inactive fibrous plaques. We proposed a new approach for noninvasive in vivo characterization of P-selectin on active plaques based on (68)Ga-Fucoidan, which is a polysaccharidic ligand of P-selectin with a nanomolar affinity. APPROACH AND RESULTS: (68)Ga-Fucoidan was tested for its potential to discriminate vulnerable plaques on apolipoprotein E-deficient mice receiving a high cholesterol diet by positron emission tomography and in correlation with 17.6T MRI. Furthermore, (68)Ga-Fucoidan was evaluated on endothelial cells in vitro and ex vivo on active plaques using autoradiography. The cellular uptake rate was increased ≈2-fold by lipopolysaccharide induction. Interestingly, on autoradiography, more intensive tracer accumulation at active plaques with thin fibrous caps and high-density foam cells were observed in comparison with a weaker focal uptake in inactive fibrous plaque segments (R=1.7±0.3; P<0.05) and fatty streaks (R=2.4±0.4; P<0.01). Strong uptake of radiotracer colocalized with increased P-selectin expression and high-density macrophage. Focal vascular uptake (mean of target to background ratio=5.1±0.8) of (68)Ga-Fucoidan was detected in all apolipoprotein E-deficient mice. Anatomic structures of plaque were confirmed by 17.6T MRI. The autoradiography showed a good agreement of (68)Ga-Fucoidan uptake with positron emission tomography. CONCLUSIONS: Our data suggest that (68)Ga-Fucoidan represents a versatile imaging biomarker for P-selectin with the potential to specifically detect P-selectin expression using positron emission tomography and to discriminate vulnerable plaques in vivo.

Monitoring of monocyte recruitment in reperfused myocardial infarction with intramyocardial hemorrhage and microvascular obstruction by combined fluorine 19 and proton cardiac magnetic resonance imaging.

BACKGROUND: Monocytes and macrophages are indispensable in the healing process after myocardial infarction (MI); however, the spatiotemporal distribution of monocyte infiltration and its correlation to prognostic indicators of reperfused MI have not been well described. METHODS AND RESULTS: With combined fluorine 19/proton ((1)H) magnetic resonance imaging, we noninvasively visualized the spatiotemporal recruitment of monocytes in vivo in a rat model of reperfused MI. Blood monocytes were labeled by intravenous injection of (19)F-perfluorocarbon emulsion 1 day after MI. The distribution patterns of monocyte infiltration were correlated to the presence of microvascular obstruction (MVO) and intramyocardial hemorrhage. In vivo, (19)F/(1)H magnetic resonance imaging performed in series revealed that monocyte infiltration was spatially inhomogeneous in reperfused MI areas. In the absence of MVO, monocyte infiltration was more intense in MI regions with serious ischemia-reperfusion injuries, indicated by severe intramyocardial hemorrhage; however, monocyte recruitment was significantly impaired in MVO areas accompanied by severe intramyocardial hemorrhage. Compared with MI with isolated intramyocardial hemorrhage, MI with MVO resulted in significantly worse pump function of the left ventricle 28 days after MI. CONCLUSIONS: Monocyte recruitment was inhomogeneous in reperfused MI tissue. It was highly reduced in MVO areas defined by magnetic resonance imaging. The impaired monocyte infiltration in MVO regions could be related to delayed healing and worse functional outcomes in the long term. Therefore, monocyte recruitment in MI with MVO could be a potential diagnostic and therapeutic target that could be monitored noninvasively and longitudinally by (19)F/(1)H magnetic resonance imaging in vivo.

Where experience makes a difference: teachers' judgment accuracy and diagnostic reasoning regarding student learning characteristics.

The concept of teacher professional vision suggests that experienced teachers, compared to novice teachers, might be better at making accurate judgments of students' learning characteristics, which can be explained by their advanced reasoning in diagnostic situations. This study examines experienced and novice teachers' diagnoses of different student characteristic profiles: three inconsistent profiles (overestimating, uninterested, and underestimating) and two consistent profiles (strong and struggling). We examined both experienced (n = 19 in-service mathematics teachers) and novice teachers (n = 24 pre-service mathematics teachers) to determine the extent of differences in their judgment accuracy and their diagnostic reasoning about observable cues when diagnosing student profiles while watching a lesson video. ANOVA results indicate that experienced teachers generally achieved a higher judgment accuracy in diagnosing student profiles compared to novice teachers. Moreover, epistemic network analysis of observable cues in experienced and novice teachers' diagnostic reasoning showed that, compared to novice teachers, experienced teachers make more relations between a broader spectrum of both surface cues (e.g., a student's hand-raising behavior) and deep cues (e.g., a student being interested in the subject). Experienced teachers thereby construct more comprehensive and robust reasoning compared to novice teachers. The findings highlight how professional experience shapes teachers' professional skills, such as diagnosing, and suggest strategies for enhancing teacher training.

Visualization of vascular inflammation in the atherosclerotic mouse by ultrasmall superparamagnetic iron oxide vascular cell adhesion molecule-1-specific nanoparticles.

OBJECTIVE: Noninvasive imaging of atherosclerosis remains challenging in clinical applications. Here, we applied noninvasive molecular imaging to detect vascular cell adhesion molecule-1 in early and advanced atherosclerotic lesions of apolipoprotein E-deficient mice. METHODS AND RESULTS: Ultrasmall superparamagnetic iron oxide particles functionalized with (P03011) or without (P3007) vascular cell adhesion molecule-1-binding peptide were visualized by ultra high-field (17.6 T) magnetic resonance. Injection of P03011 resulted in a marked signal loss in the aortic root of apolipoprotein E-deficient mice fed a Western diet for 8 and 26 weeks in vivo and ex vivo, compared with preinjection measurements, P3007-injected mice, and P03011- or P3007-injected age-matched C57BL/6 controls. Histological analyses revealed iron accumulations in the intima, in colocalization with vascular cell adhesion molecule-1-expressing macrophages and endothelial cells. Coherent anti-Stokes Raman scattering microscopy demonstrated iron signals in the intima and media of the aortic root in the P03011-injected but not untreated apolipoprotein E-deficient mice, localized to macrophages, luminal endothelial-like cells, and medial regions containing smooth muscle cells. Electron microscopy confirmed iron particles enclosed in endothelial cells and in the vicinity of smooth muscle cells. CONCLUSIONS: Using a combination of innovative imaging modalities, in this study, we demonstrate the feasibility of applying P03011 as a contrast agent for imaging of atherosclerosis.

Implementing Remote Collaboration in a Virtual Patient Platform: Usability Study.

BACKGROUND: Learning with virtual patients is highly popular for fostering clinical reasoning in medical education. However, little learning with virtual patients is done collaboratively, despite the potential learning benefits of collaborative versus individual learning. OBJECTIVE: This paper describes the implementation of student collaboration in a virtual patient platform. Our aim was to allow pairs of students to communicate remotely with each other during virtual patient learning sessions. We hypothesized that we could provide a collaborative tool that did not impair the usability of the system compared to individual learning and that this would lead to better diagnostic accuracy for the pairs of students. METHODS: Implementing the collaboration tool had five steps: (1) searching for a suitable software library, (2) implementing the application programming interface, (3) performing technical adaptations to ensure high-quality connections for the users, (4) designing and developing the user interface, and (5) testing the usability of the tool in 270 virtual patient sessions. We compared dyad to individual diagnostic accuracy and usability with the 10-item System Usability Scale. RESULTS: We recruited 137 students who worked on 6 virtual patients. Out of 270 virtual patient sessions per group (45 dyads times 6 virtual patients, and 47 students working individually times 6 virtual patients minus 2 randomly selected deleted sessions) the students made successful diagnoses in 143/270 sessions (53%, SD 26%) when working alone and 192/270 sessions (71%, SD 20%) when collaborating (P=.04, η2=0.12). A usability questionnaire given to the students who used the collaboration tool showed a usability score of 82.16 (SD 1.31), representing a B+ grade. CONCLUSIONS: The collaboration tool provides a generic approach for collaboration that can be used with most virtual patient systems. The collaboration tool helped students diagnose virtual patients and had good overall usability. More broadly, the collaboration tool will provide an array of new possibilities for researchers and medical educators alike to design courses for collaborative learning with virtual patients.

Multi-center real-world comparison of the fully automated Idylla™ microsatellite instability assay with routine molecular methods and immunohistochemistry on formalin-fixed paraffin-embedded tissue of colorectal cancer.

Microsatellite instability (MSI) is present in 15-20% of primary colorectal cancers. MSI status is assessed to detect Lynch syndrome, guide adjuvant chemotherapy, determine prognosis, and use as a companion test for checkpoint blockade inhibitors. Traditionally, MSI status is determined by immunohistochemistry or molecular methods. The Idylla™ MSI Assay is a fully automated molecular method (including automated result interpretation), using seven novel MSI biomarkers (ACVR2A, BTBD7, DIDO1, MRE11, RYR3, SEC31A, SULF2) and not requiring matched normal tissue. In this real-world global study, 44 clinical centers performed Idylla™ testing on a total of 1301 archived colorectal cancer formalin-fixed, paraffin-embedded (FFPE) tissue sections and compared Idylla™ results against available results from routine diagnostic testing in those sites. MSI mutations detected with the Idylla™ MSI Assay were equally distributed over the seven biomarkers, and 84.48% of the MSI-high samples had ≥ 5 mutated biomarkers, while 98.25% of the microsatellite-stable samples had zero mutated biomarkers. The concordance level between the Idylla™ MSI Assay and immunohistochemistry was 96.39% (988/1025); 17/37 discordant samples were found to be concordant when a third method was used. Compared with routine molecular methods, the concordance level was 98.01% (789/805); third-method analysis found concordance for 8/16 discordant samples. The failure rate of the Idylla™ MSI Assay (0.23%; 3/1301) was lower than that of referenced immunohistochemistry (4.37%; 47/1075) or molecular assays (0.86%; 7/812). In conclusion, lower failure rates and high concordance levels were found between the Idylla™ MSI Assay and routine tests.

Macrocyclic NHC complexes of group 10 elements with enlarged aromaticity for biological studies.

Two sets of macrocyclic, bio-inspired, non-heme ligands are utilized for the synthesis of NiII, PdII and PtII complexes. The ligands consist of a 16-atom macrocycle, formed by four methylene bridged NHC moieties, with imidazole or benzimidazole as building blocks. The complexes exhibit a square planar coordination geometry and are characterized by NMR, ESI-MS, elemental analysis, SC-XRD and UV/Vis. For complexes incorporating benzimidazole, an evaluation of luminescence properties is performed, and is found that phosphorescence is present for the PdII derivative and there is fluorescence for the PtII derivative. Stability studies in cell culture medium are performed for subsequent MTT assays. Here, the NiII complexes show low to no activity, and PdII and PtII complexes exhibit remarkable low IC50 values in cisplatin resistant A2780cisR cells.

Diagnostic Activities and Diagnostic Practices in Medical Education and Teacher Education: An Interdisciplinary Comparison.

In this article, we investigate diagnostic activities and diagnostic practices in medical education and teacher education. Previous studies have tended to focus on comparing knowledge between disciplines, but such an approach is complicated due to the content specificity of knowledge. We compared 142 learners from medical education and 122 learners from teacher education who were asked to (a) diagnose eight simulated cases from their respective discipline in a simulation-based learning environment and (b) write a justificatory report for each simulated case. We coded all justificatory reports regarding four diagnostic activities: generating hypotheses, generating evidence, evaluating evidence, and drawing conclusions. Moreover, using the method of Epistemic Network Analysis, we operationalized diagnostic practices as the relative frequencies of co-occurring diagnostic activities. We found significant differences between learners from medical education and teacher education with respect to both their diagnostic activities and diagnostic practices. Learners from medical education put relatively more emphasis on generating hypotheses and drawing conclusions, therefore applying a more hypothesis-driven approach. By contrast, learners in teacher education had a stronger focus on generating and evaluating evidence, indicating a more data-driven approach. The results may be explained by different epistemic ideals and standards taught in higher education. Further research on the issue of epistemic ideals and standards in diagnosing is needed. Moreover, we recommend that educators think beyond individuals' knowledge and implement measures to systematically teach and increase the awareness of disciplinary standards.

Synthesis, characterization, and biological studies of multidentate gold(i) and gold(iii) NHC complexes.

The synthesis and characterization of a novel macrocyclic Au(iii) N-heterocyclic carbene (NHC) imidazolyl complex, a novel macrocyclic tetra-NHC benzimidazole ligand, and the corresponding Ag(i) and Au(i) complexes are presented. Single-crystal X-ray diffraction analysis of the Au(i) benzimidazolyl complex 3 reveals an unusual structure, differing from the respective Au(i) imidazolyl complex 4. Both complexes have a Au4L2 composition; however, 3 has two C-Au(i)-C units acting as a connection between the two ligands with two Au(i) atoms being linearly coordinated inside the cavity of the macrocyclic ligand. In the case of complex 4, the structure shows a box-type coordination with all four Au(i) atoms being located between the two ligands. Stability studies in cell culture medium are performed for subsequent MTT assays and they show an unprecedented proton-to-deuterium exchange of the methylene bridge of the Au(iii) imidazolyl complex. In MTT assays, the tetranuclear acyclic Au(i) complex 5 displays the lowest IC50 values in MCF-7, PC3, and A2780cisR cells with a selective cytotoxicity for MCF-7 and A2780cisR cells.

Local arterial stiffening assessed by MRI precedes atherosclerotic plaque formation.

BACKGROUND: Atherosclerosis is known to impair vascular function and cause vascular stiffening. The aim of this study was to evaluate the potential predictive role of vascular stiffening in the early detection of atherosclerosis. Therefore, we investigated the time course of early functional and morphological alterations of the vessel wall in a murine atherosclerosis model. Because initial lesions are distributed inhomogeneously in early-stage atherosclerosis, MR microscopy was performed to measure vascular elasticity locally, specifically the local pulse wave velocity and the arterial wall thickness. METHODS AND RESULTS: Local pulse wave velocity and the mean arterial wall thickness were determined in the ascending and the abdominal aortae of ApoE(-/-) and wild-type mice. In vivo MRI revealed that baseline pulse wave velocity and morphology were similar in 6-week-old ApoE(-/-) and WT mice, whereas at the age of 18 weeks, local pulse wave velocity was significantly elevated in ApoE(-/-) mice. Significantly increased vessel wall thickness was not found in ApoE(-/-) mice until the age of 30 weeks. Histological analysis of the aortae of ApoE(-/-) and WT mice showed that increased pulse wave velocity coincided with the fragmentation of the elastic laminae in the arterial wall, which is hypothesized to induce early vascular stiffening and may be promoted by macrophage-mediated matrix degradation. CONCLUSIONS: We newly report that the assessment of local pulse wave velocity via MRI provides early information about the local progression of atherosclerosis before macroscopic alterations of the vessel wall occur.

Specific somatostatin receptor II expression in arterial plaque: (68)Ga-DOTATATE autoradiographic, immunohistochemical and flow cytometric studies in apoE-deficient mice.

BACKGROUND: The rupture of atherosclerotic plaques is triggered by inflammation. Specific detection of inflammation is therefore the focus of many investigations. Noninvasive imaging methods, such as positron emission tomography (PET), also are suited for this purpose. (68)Ga-DOTATATE is a (68)Ga-labeled radiotracer with specific affinity to somatostatin receptor subtype-2 (SSTR-2). SSTR-2 was found specifically expressed on human macrophages/monocytes. OBJECTIVE: We aimed to confirm the distribution of SSTR-2 in inflammatory plaques, and to assess its co-localization with macrophages within the plaques. We also assessed (68)Ga-DOTATATE uptakes in plaques by autoradiography. METHOD: Apolipoprotein E (ApoE)-/- mice on a high-cholesterol diet were injected with (68)Ga-DOTATATE. The animals were sacrificed and aorta sections were examined using autoradiography and immunohistochemistry. Furthermore, expression of SSTR-2 was analyzed by flow cytometry. Western blot was conducted to assess SSTR-2 regulation in basal and lipopolysaccharide (LPS)-activated state. To evaluate the specificity of the (68)Ga-DOTATATE, the sections were pre-incubated with monoclonal SSTR-2 antibody before autoradiography. RESULT: Autoradiographic imaging showed uptake of (68)Ga-DOTATATE co-localized with the macrophage-rich plaques by immunohistochemical examination. A high expression of SSTR-2 on macrophages was found by flow cytometry and western blot. Stimulation with lipopolysaccharide did not alter expression of SSTR-2 in macrophages. CONCLUSION: Due to its specific binding to macrophages, (68)Ga-DOTATATE might be a suitable radiotracer for the evaluation of inflammatory activity in unstable plaques.

Parâmetros de avaliaçäo nutricional: säo úteis em prognosticar complicaçöes pós-cirúrgicas e maior tempo de hospitalizaçäo? / Parameters of nutritional assessment: are them usuful to prognosticate post operative complication and larger length of stay?

Parâmetros objetivos e subjetivos de Avaliaçäo do Estado nutricional obtidos na admissäo hospitalar foram estudados para determinar se seriam capazes de predizer complicaçöes pós-cirurgicas e maior tempo de hospitalizaçäo em 125 pacientes admitidos para cirurgia eletiva. Nos parâmetros objetivos figuraram dados antropométricos e bioquímicos, adotados na rotina hospitalar, enquanto os subjetivos contemplaram avaliaçöes da história alimentar, ponderal, clínica e social. Os resultados revelaram uma grande proporçäo de pacientes com estado nutricional normal avaliados tanto por parâmetros objetivos (85%) quanto pelos subjetivos (79%). A taxa de morbidade foi de 35% com 4% de mortalidade. Relaçäo peso e altura foi o parâmetro que correlacionou com aparecimento de complicaçöes enquanto relaçäo peso e altura, circunferência muscular do braço, hemoglobina, hematócrito, presença de doença crônica e classificaçäo global do estado nutricional por métodos objetivos mostraram correlaçäo significativa com maior permanência hospitalar. Esses dados mostram a importância de avaliar outras variáveis que indiquem o estado nutricional näo somente no período de admissäo como também durante a hospitalizaçäo. Outro fato a ser destacado é a correlaçäo encontrada entre a avaliaçäo global objetiva (AGO) e subjetiva (AGS) e a maior estada. Isto sugere que mais do que identificar isoladamente parâmetros nutricionais preditivos, é possível classificar globalmente o estado nutricional, com o conjunto de técncias disponíveis em cada Hospital e, consequentemente promover correlaçöes de possíveis alteraçöes do estado nutricional e contribuir para um melhor prognóstico