How authenticity impacts validity: Developing a model of teacher education assessment and exploring the effects of the digitisation of assessment methods.

Based on a literature review of studies on teachers' professional competence and related assessment tools, this paper introduces a model of teacher education assessment. It is influenced by Miller's (1990) framework of assessment in medical education and includes, among other aspects, performance assessments. This model is used to understand the potential effects of transferring assessment tools into a digital format with assessment feedback. Five examples for such a transfer will be discussed: three methods for various aspects of communication, a test for pedagogical content knowledge, and a test for content knowledge. All five are established instruments well-described in terms of validity. All five have recently been transferred into a digital format. The analysis of this transfer also reveals a potentially harmful effect of digital assessment. The closer an assessment instrument is to assessing action-related parts of professional competence, the more authenticity is required; however, digitisation tends to decrease this authenticity. This suggests that an increasing number of digital assessment tools in teacher education might result in an even more dominant focus on knowledge tests, ignoring other parts of professional competence. This article highlights the role of authenticity in validity and discusses the most suitable assessment format to address various parts of professional competence. It ends by highlighting the lessons learned from the transfer of assessment instruments into a digital format that other academic disciplines might find interesting.

Additive Manufacturing-Based In Situ Consolidation of Continuous Carbon Fibre-Reinforced Polycarbonate.

Continuous carbon fibre-reinforced thermoplastic composites have convincing anisotropic properties, which can be used to strengthen structural components in a local, variable and efficient way. In this study, an additive manufacturing (AM) process is introduced to fabricate in situ consolidated continuous fibre-reinforced polycarbonate. Specimens with three different nozzle temperatures were in situ consolidated and tested in a three-point bending test. Computed tomography (CT) is used for a detailed analysis of the local material structure and resulting material porosity, thus the results can be put into context with process parameters. In addition, a highly curved test structure was fabricated that demonstrates the limits of the process and dependent fibre strand folding behaviours. These experimental investigations present the potential and the challenges of additive manufacturing-based in situ consolidated continuous fibre-reinforced polycarbonate.

Biopolymer surface modification of PLGA fibers enhances interfacial shear strength and supports immobilization of rhGDF-5 in fiber-reinforced brushite cement.

Incorporation of biodegradable poly(lactic-co-glycolic acid; PLGA) fibers into calcium phosphate cements (CPCs) has proven beneficial for their mechanical properties and the targeted delivery of bone morphogenetic proteins (BMPs). However, the deficiency of functional groups on the PLGA surface results in poor fiber-matrix interfacial strength (ISS), limiting the mechanical improvement, and insufficient surface charge to immobilize therapeutic amounts of BMPs. The present study therefore focused on the: i) functionalization of PLGA fibers using polyelectrolyte multilayers (PEMs) of biopolymers; ii) analysis of their impact on the mechanical properties of the CPC in multifilament fiber pull-out tests; and iii) testing of their applicability as carriers for BMPs using chemical-free adsorption of biotinylated recombinant human growth factor (rhGDF-5) and colorimetric assays. The PEMs were created from chitosan (Chi), hyaluronic acid (HA), and gelatin (Gel) via layer-by-layer (LbL) deposition. Four PEM nanocoatings consisting of alternating Chi/Gel and Chi/HA bilayers with a terminating layer of Chi, Gel or HA were tested. Nanocoating of the PLGA fibers with PEMs significantly enhanced the ISS with the CPC matrix to max. 3.55 ± 1.05 MPa (2.2-fold). The increase in ISS, ascribed to enhanced electrostatic interactions between PLGA and calcium phosphate, was reflected in significant improvement of the composites' flexural strength compared to CPC containing untreated fibers. However, only minor effects on the composites' work of fracture were observed. The adsorption of rhGDF-5 on the PLGA surface was supported by PEMs terminating with either positive or negative charges, without significant differences among the nanocoatings. This proof-of-principle rhGDF-5 immobilization study, together with the augmented ISS of the composites, demonstrates that surface modification of PLGA fibers with biopolymers is a promising approach for targeted delivery of BMPs and improved mechanical properties of the fiber-reinforced CPC.

Relevance of Leaflet Prolapse to the Indication Policy for Aortic Valve-Sparing Root Replacement.

BACKGROUND: In aortic root replacement, "preexisting" or "induced" aortic leaflet prolapse is related to advanced aortic root pathology and can indicate valve repair. Efforts should be made to perform root replacement before leaflet prolapse is in its maximum extent. MATERIALS AND METHODS: Thirty-nine patients with chronic aortic root dilatation and aortic valve regurgitation (AR) underwent a reimplantation procedure. Contrary to 32 of the 39 patients (group A), 7 of the 39 patients (group B) underwent cusp plication for prolapse. For both groups, data related to the diameter at the level of maximal tubular extension, sinotubular junction, sinus of Valsalva, aorto-ventricular junction (AVJ), and aortic annulus were obtained from preoperative computed tomography scans and analyzed comparatively. RESULTS: Group B showed a higher mean AR grade (P = .007), a higher mean diameter at the level of the aortic annulus (P = .038), AVJ (P = .037), and aortic sinus (P <.001) and a higher sinus dilatation index (existing-to-predicted diameter ratio) (P <.001) than group A. The sinus of Valsalva displayed the best predictive value regarding a plicature-indicating prolapse (P <.001; 95% confidence interval [CI]: 0.809-1.013). A diameter >40 mm was accompanied by an odds ratio (OR) of 24.6 (95% CI: 1.29-496.02). During the follow-up period of 29.0 ± 18.4 months (range: 6-62 months), 1 patient (group A) required reoperation 5 years postoperatively for progressive AR. CONCLUSION: The sinus of Valsalva diameter seems to have the greatest prognostic value for the development of prolapse. Our data suggest that root repair should be considered earlier in time before leaflet prolapse is complete, which most likely occurs when root dilatation becomes an aneurysm.

Cytokine-Like 1 Is a Novel Proangiogenic Factor Secreted by and Mediating Functions of Endothelial Progenitor Cells.

RATIONALE: Endothelial colony forming cells (ECFCs) or late blood outgrowth endothelial cells can be isolated from human cord or peripheral blood, display properties of endothelial progenitors, home into ischemic tissues and support neovascularization in ischemic disease models. OBJECTIVE: To assess the functions of CYTL1 (cytokine-like 1), a factor we found preferentially produced by ECFCs, in regard of vessel formation. METHODS AND RESULTS: We show by transcriptomic analysis that ECFCs are distinguished from endothelial cells of the vessel wall by production of high amounts of CYTL1. Modulation of expression demonstrates that the factor confers increased angiogenic sprouting capabilities to ECFCs and can also trigger sprouting of mature endothelial cells. The data further display that CYTL1 can be induced by hypoxia and that it functions largely independent of VEGF-A (vascular endothelial growth factor-A). By recombinant production of CYTL1 we confirm that the peptide is indeed a strong proangiogenic factor and induces sprouting in cellular assays and functional vessel formation in animal models comparable to VEGF-A. Mass spectroscopy corroborates that CYTL1 is specifically O-glycosylated on 2 neighboring threonines in the C-terminal part and this modification is important for its proangiogenic bioactivity. Further analyses show that the factor does not upregulate proinflammatory genes and strongly induces several metallothionein genes encoding anti-inflammatory and antiapoptotic proteins. CONCLUSIONS: We conclude that CYTL1 can mediate proangiogenic functions ascribed to endothelial progenitors such as ECFCs in vivo and may be a candidate to support vessel formation and tissue regeneration in ischemic pathologies.

Surgical decision making for revascularization of chronically occluded right coronary artery.

OBJECTIVE: Chronic totally occluded right coronary artery (CTO-RCA) often poses a problem in decision making for/against bypass grafting due to the lack of standardized indication criteria. The aim of the study was to investigate whether qualitative angiograms can be useful in decision making for/against surgical revascularization of CTO-RCA. METHODS: A retrospective cohort study was conducted with 69 patients who underwent elective CABG procedure, including single graft to the RCA. The distal run-off of the bypassed RCA was measured intraoperatively using the ultrasonic transit-time method. As a primary endpoint of the study, the flow values were analysed in regard to diameter of the recipient artery. As a secondary endpoint, the correlations between the regional and global LV function, Rentrop grading, type of collateral pathway, number of donor sources, comorbidity, and the graft flow and the diameter of the recipient artery were investigated using uni- and multi-variate regression analyses. RESULTS: In general, the flow values correlated significantly with the diameter of the recipient artery. Significantly lower flow (p < 0.0001) and diameter values (p < 0.05) were found in hypo/akinetic and infarcted area reflecting functionality of the CTO-RCA territory. CONCLUSIONS: The qualitative angiograms combined with regional wall motion studies can be useful in decision making for revascularization of CTO-RCA. Revascularization of akinetic/infarcted CTO-RCA territory is associated with lower graft flows even in patients presented with high Rentrop class and high degree of collaterality, suggesting necessity of viability tests prior to bypass surgery.

Blockade of thymic stromal lymphopoietin (TSLP) receptor inhibits TSLP-driven proliferation and signalling in lymphoblasts from a subset of B-precursor ALL patients.

PURPOSE: The cytokine thymic stromal lymphopoietin (TSLP) and its receptor TSLPR are involved in intercellular communication in the course of allergic inflammation and have recently been implicated in the development of various malignancies including B cell precursor acute lymphoblastic leukemia (BCP-ALL). We studied TSLPR expression, TSLP-induced signal transduction and its antibody-mediated inhibition in long-term cultures of primary cells derived from B-precursor ALL patients. METHODS: TSLPR expression was determined by flow cytometry and Western blot analysis, cell proliferation, signal transduction via the JAK/STAT pathway was analysed by Western blot detection of STAT tyrosine phosphorylation and by measuring TSLP-dependent activation of a STAT-specific reporter gene construct. For inhibition studies a recently introduced antagonistic antibody to the TSLPRα-subunit was used. RESULTS: TSLPR surface expression was observed in leukemic lymphoblasts from two out of ten patients with BCP-ALL. Upon TSLP stimulation, the cells with the highest TSLPR expression level showed enhanced proliferation and JAK/STAT-mediated gene regulation in a dose-dependent manner. By employment of an inhibitory antibody to the TSLPR, both TSLP-triggered cell proliferation and STAT transcription factor activation were specifically inhibited. CONCLUSIONS: These results suggest that blockade of the TSLPR might be a therapeutic option for a subset of BCP-ALL patients.

Calcium Pyrophosphate Dihydrate Crystal Deposition Disease of the Sternoclavicular Joint.

Deposition of calcium pyrophosphate dihydrate (CPPD) crystals in the articular structures affects predominantly temporomandibular, knee, hip, spine, and wrist joints, and is a rare condition, often mimicking malignancy. Sternoclavicular joint is extremely rarely involved. We present a patient with swelling of the right upper extremity, in whom on computed tomography a mass posterior to the sternoclavicular joint causing compression of the brachiocephalic vein was detected. A modified resection arthroplasty was performed, and the histopathological findings revealed massive deposits of CPPD in the articular cartilage. To our knowledge, there is only one similar case published in the literature.

Intermittent Cold-Blood Cardioplegia and Its Impact on Myocardial Acidosis during Coronary Bypass Surgery.

BACKGROUND: The purpose of the study was to assess the degree of myocardial acidosis in patients undergoing elective coronary bypass surgery, in whom intermittent cold-blood cardioplegia (ICBC) was used for myocardial protection. The results of this study are presented in comparison to those of a previous trial conducted by the same investigators, using a similar methodology, but with intermittent warm-blood cardioplegia (IWBC). PATIENTS AND METHODS: In 15 patients undergoing elective myocardial revascularization with ICBC for myocardial protection, metabolic changes of global ischemia indicators, lactate and pH values (measured simultaneously in coronary sinus and arterial blood) were analyzed. Lactate concentrations and pH values were measured at the beginning and the end of each cardioplegia administration, and the change-overtime analysis of the values was performed. For comparison with the results of the previous study (IWBC method) consisting of 12 patients, the analysis of variance with repeated measurements, including tests for a crossover, group, and time effect were used. RESULTS: Using the ICBC method, as compared with IWBC, no significant difference in the lactate production was observed during the first two successive cardioplegia administrations. During the third and fourth administrations, especially at the end of reperfusions, ICBC patients had a significantly lower lactate release and higher pH values, as compared with IWBC patients. CONCLUSION: Our results suggest that ICBC has an inhibiting effect on potentially progressive myocardial acidosis during cross-clamp period.

Expression analysis and specific blockade of the receptor for human thymic stromal lymphopoietin (TSLP) by novel antibodies to the human TSLPRα receptor chain.

Thymic stromal lymphopoietin (TSLP) is an interleukin-7 (IL-7)-like cytokine with a pivotal role in development and maintenance of atopic diseases such as allergic asthma and atopic dermatitis. Moreover, recent studies show an involvement of TSLP in the progression of various cancers. TSLP signaling is mediated by the TSLP receptor (TSLPR), a heterodimeric type I cytokine receptor. It consists of the IL-7 receptor alpha chain (IL-7Rα), which is shared with the IL-7 receptor, and the TSLPRα chain as a specific subunit. Blocking signal release by TSLP without affecting IL-7 function is a potentially interesting option for the treatment of atopic diseases or certain tumors. By employing the extracellular domain of human TSLPRα chain (hTSLPRα(ex)) as an antigen, we generated a set of monoclonal antibodies. Several binders to native and/or denatured receptor protein were identified and characterized by cytometry and Western blot analysis. A screen based on a STAT3-driven reporter gene assay in murine pro-B cells expressing a functional hTSLPR yielded two hybridoma clones with specific antagonistic properties towards hTSLP, but not IL-7. Kinetic studies measuring blockade of hTSLP-dependent STAT phosphorylation in a TSLP-responsive cell line revealed an inhibitory constant in the nanomolar range.

Metabolic monitoring of postischemic myocardium during intermittent warm-blood cardioplegic administration.

In 12 patients undergoing elective myocardial revascularization with intermittent administration of warm-blood cardioplegic solution for myocardial protection, we analyzed metabolic changes by assay of global ischemia indicators (pH, lactate, glucose, and potassium), which we measured in the coronary sinus and arterial blood during the ischemic and postischemic periods. A typical cumulative ischemic pattern with progressively decreasing pH values and progressively increasing lactate values could not be observed in all patients. It was not the degree of lactate washout, but the lactate concentration at the end of each reperfusion, that correlated significantly with global metabolic recovery time, which suggests the importance of effective reperfusion.

Signal transduction by the atopy-associated human thymic stromal lymphopoietin (TSLP) receptor depends on Janus kinase function.

Thymic stromal lymphopoietin (TSLP) is an interleukin-(IL)-7-like cytokine with emerging pathological importance for the development of atopic diseases such as allergic asthma bronchiale. The TSLP receptor (TSLPR), a heterodimeric type I cytokine receptor, shares the IL-7R alpha-subunit with the IL-7 receptor system. The specific TSLPR alpha-chain shows similarities with the gammac receptor chain, but has some unusual features within the receptor family in both its ligand-binding and cytoplasmic domain. The murine TSLPR signals via the signal transducers and activators of transcription STAT5 and STAT3, but is unique among cytokine receptors in that it activates STATs without the involvement of Janus (JAK) tyrosine kinases, but instead utilizes the Src type kinase Tec. Here, we show by Western blotting and reporter gene experiments in combination with the application of a specific JAK inhibitor that the human TSLP receptor, in contrast, requires the function of JAK1 and JAK2 for STAT activation. Moreover, we demonstrate that the human TSLPR mediates gene regulation not only through STAT5 and STAT3 but has also the potential to mediate transcription via STAT1. Our work should help to understand more thoroughly how TSLP triggers inflammatory responses in the course of atopic diseases.

Impact of preconditioning protocol on anesthetic-induced cardioprotection in patients having coronary artery bypass surgery.

OBJECTIVE: Anesthetic preconditioning may contribute to the cardioprotective effects of sevoflurane in patients having coronary artery bypass surgery. We investigated whether 2 different sevoflurane administration protocols can induce preconditioning in patients having coronary artery bypass. METHODS: Thirty patients were randomly allocated to 1 of 3 groups. All patients received a total intravenous anesthesia with sufentanil (0.3 microg(-1) x kg x h(-1)) and propofol as target controlled infusion (2.5 microg/mL). The control group had no further intervention; 10 minutes prior to establishing the extracorporeal circulation, patients of the sevoflurane-I group received 1 minimum alveolar concentration of sevoflurane for 5 minutes. Patients of the sevoflurane-II group received (2 times) 5 minutes of sevoflurane, interspersed by 5-minute washout 10 minutes prior to extracorporeal circulation. Troponin I was measured as marker of cardiac cellular damage. RESULTS: Peak levels of troponin I release were observed at 4 hours after cardiopulmonary bypass and were not affected by 1 cycle of sevoflurane administration (controls: 14 +/- 3 ng/mL vs sevoflurane-I group, 14 +/- 3 ng/mL). Two periods of sevoflurane preconditioning significantly reduced cellular damage compared with controls (peak troponin I level sevoflurane-II group, 7 +/- 2 ng/mL). CONCLUSION: These data show that sevoflurane-induced preconditioning is reproducible in patients having coronary artery bypass but depends on the preconditioning protocol used.

Signal transduction around thymic stromal lymphopoietin (TSLP) in atopic asthma.

Thymic stromal lymphopoietin (TSLP), a novel interleukin-7-like cytokine, triggers dendritic cell-mediated inflammatory responses ultimately executed by T helper cells of the Th2 subtype. TSLP emerged as a central player in the development of allergic symptoms, especially in the airways, and is a prime regulatory cytokine at the interface of virus- or antigen-exposed epithelial cells and dendritic cells (DCs). DCs activated by epithelium-derived TSLP can promote naïve CD4+ T cells to adopt a Th2 phenotype, which in turn recruite eosinophilic and basophilic granulocytes as well as mast cells into the airway mucosa. These different cells secrete inflammatory cytokines and chemokines operative in inducing an allergic inflammation and atopic asthma. TSLP is, thus, involved in the control of both an innate and an adaptive immune response. Since TSLP links contact of allergen with the airway epithelium to the onset and maintainance of the asthmatic syndrome, defining the signal transduction underlying TSLP expression and function is of profound interest for a better understandimg of the disease and for the development of new therapeutics.

Coronary artery disease progression in patients who need repeat surgical revascularisation: the surgeon's point of view.

OBJECTIVE: The purpose of this study was to evaluate changes in native coronary arteries in patients undergoing repeat myocardial revascularisation late (>3 years) after primary coronary artery bypass grafting (CABG). METHODS: The angiographic images of 30 patients obtained at first and redo CABG were assessed for significant (>75%), short (<1 cm) and long (>1 cm) stenosis or total occlusion in native coronary arteries. Bypass grafts were also evaluated for significant stenosis (>50%) or occlusion. RESULTS: At first CABG, a mean number of 3.3 grafts/patient (range 1-5) were implanted. The mean time interval from first CABG to reoperation was 11.4 years (range 3-21 years). All patients showed disease progression in the native coronary arteries. At redo CABG, 3 (3.5%) grafts were non-stenotic, 27 (31%) stenotic, and 57 (65.5%) occluded. In native coronary vessels, five patients developed a new left main coronary artery stenosis, and there was a four-to-six-fold increase in total occlusions. Indications for redo CABG were disease progression in non-bypassed vessels (n = 3), bypass lesions (n = 19), and both bypass lesions and disease progression in the distal segments of native coronary arteries (n = 8). CONCLUSIONS: Late after CABG, coronary artery disease is highly progressive, mainly affecting the proximal segments of native coronary arteries, with a high incidence of coronary occlusion. Conversely, a low incidence of disease progression is observed in the distal segments of native coronary arteries, except in diabetic patients. Total arterial revascularisation as a primary strategy for CABG should be highly recommended, and more aggressive risk factor management is desirable.

A modification to the Manouguian aortoplasty for biological valve implantation in patients with small (< or =19 mm) aortic anuli--rationale and benefit.

Enlargement of a small aortic root using the Manouguian technique for biological valve implantation can be challenging when rigid, severely calcified noncoronary parts of the aortic anulus are encountered in combination with outsized heights of interleaflet triangles. To maximize the efficacy of the Manouguian technique, we applied a modification--the rationale, technical details, and benefits of which we describe herein.

Surgery for severe aortic stenosis with low transvalvular gradient and poor left ventricular function -- a single centre experience and review of the literature.

BACKGROUND: A retrospective comparative study was designed to determine whether the transvalvular gradient has a predictive value in the assessment of operative outcome in patients with severe aortic stenosis and poor left ventricular function. METHODS: From a surgical database, a series of 30 consecutive patients, who underwent isolated aortic valve replacement for severe aortic stenosis with depressed left ventricular (LV) function (EF < 40%), were enrolled in the study and divided into two groups according to the mean transvalvular gradient (TVG): LG(low gradient)-Group < 40 mmHg (n = 13), and HG(high gradient)-Group > 40 mmHg (n = 17). Both groups were then comparatively assessed with respect to perioperative organ functions and mortality. RESULTS: Both groups were well matched with respect to the preoperative clinical status. LG-Group had a larger aortic valve area, higher LVEDP, larger LVESD and LVEDD, and higher mean pulmonary pressures. The immediate postoperative outcome, hospital morbidity and mortality did not differ significantly among the groups. CONCLUSION: In patients with severe aortic stenosis and poor LV function, the mean transvalvular gradient, although corresponds to reduced LV performance, has a limited prognostic value in the assessment of surgical outcome. Generally, operating on this select group of patients is safe.

Blockade of interleukin-13-mediated cell activation by a novel inhibitory antibody to human IL-13 receptor alpha1.

Interleukin-13 (IL-13) is a cytokine with a crucial role in the development of allergic asthma. The IL-13 receptor shares the IL-4Ralpha subunit with the IL-4R system, but contains as a specific component the IL-13Ralpha1 chain. Blocking signal release by IL-13 without affecting IL-4 function is a potentially interesting therapeutical option for the treatment of asthma. Employing genetic immunization, we generated a set of novel monoclonal antibodies to the IL-13Ralpha1 receptor that proved very specific and efficient inhibitors of human IL-13 activity. Receptor binding antibodies were identified by their specific reactivity with both human monocytes and a murine pro-B cell line overexpressing human IL-13Ralpha1 by flow cytometry and cell ELISA. A luciferase reporter cell system based on STAT6-mediated promoter activation in murine Ba/F3 cells was employed to screen the antibodies for IL-13 antagonistic properties. Inhibitory antibody effects were quantified by interference with IL-13-dependent proliferation of TF-1 cells. The capability of blocking IL-13-driven responses of primary, inflammation-relevant cells was tested by Western blot analysis of STAT6 tyrosine phosphorylation and expression of 15-lipoxygenase in monocytes from fresh blood. The most potent inhibitory antibody identified, GM1E7, inhibited IL-13-driven gene activation and cell proliferation in immune cell lines with IC(50) values in the low nanomolar range. Both short-term (STAT6 activation) and long-term (15-LO induction) responses of primary human blood cells to IL-13 were almost entirely blocked, whereas IL-4 effects remained virtually unaffected. GM1E7 is superior to available agents interfering with IL-13 activity in terms of specificity and efficiency and offers potential novel therapeutic perspectives for the treatment of allergic asthma.

Recurrent embolism in the course of marantic endocarditis.

Marantic or nonbacterial thrombotic endocarditis (NBTE) associated with systemic embolism is usually a complication of advanced or terminal malignancies. We report on the case of a 46-year-old woman in whom nonbacterial thrombotic endocarditis (NBTE)-related cerebral embolism was the first clinical sign of ovarian neoplasm, which was diagnosed after cardiac surgery. Marantic endocarditis should alert the physician to make every effort to diagnose the possible background of this clinical phenomenon. Early identification of NBTE, treatment of the underlying disease, and the associated coagulopathy could possibly prevent cardiac surgery.

Stroke as a first manifestation of ovarian cancer.

BACKGROUND: Gynaecologic neoplasms are reported to have the highest potential for developing of ischemic stroke. OBJECTIVES: The history of a female patient, in whom recurrent cerebral embolism was the first clinical sign of occult ovarian neoplasm is described and the casuistic literature to characterise this clinical phenomenon reviewed. RESULTS: Among a large spectrum of neoplasms complicating with ischemic stroke, ovarian carcinoma is one of the most frequently reported in the casuistic literature. The source of systemic microembolisation is endocardits of non-infectious origin; the characteristic diagnostic findings are thrombocytopenia, elevated D-dimers level, and a specific stroke pattern in magnetic resonance imaging. CONCLUSION: Meticulous diagnosis in female, otherwise 'healthy' patients with ischemic stroke, to detect the underlying neoplastic disease is of paramount importance, as early surgical intervention on cancer promises successful therapy for both, cancer and thromboembolism.