Differential tissue sparing of FLASH ultra high dose rates: an {\it in-silico} study

Purpose: To propose a theory for the differential tissue sparing of FLASH ultra high dose rates (UHDR) through inter-track reaction-diffusion mechanism. Methods: We calculate the time-evolution of particle track-structures using a system of coupled reaction-diffusion equations on a random network designed for molecular transport in porous and disordered media. The network is representative of the intra- and inter-cellular diffusion channels in tissues. Spatial cellular heterogeneities over the scale of track spacing have been constructed by incorporating random fluctuations in the connectivity among network sites. Results: We demonstrate the occurrence of phase separation among the tracks as the complexity in intra- and inter-cellular structural increases. At the weak limit of disorder, such as in water and normal tissue, neighboring tracks melt into each other and form a percolated network of nonreactive species. In contrast, at the strong limit of disorder, tracks evolve individually like isolated islands with negligible inter-track overlap. Thus, the spatio-temporal correlation among the chemical domains decreases as the inter-cellular complexity of the tissue increases (e.g. from normal tissue to fractal-type malignant tissue). Conclusions: The differential sparing of FLASH UHDR in normal and tumor tissue may be explained by differences in inter- and intra-cellular structural complexities between the tissue types. The structural complexities of cancerous cells prevent clustering and chemical interaction of tracks, whereas this interaction prevails and thus leads to sparing in normal tissue

Perspectives on the revised Ghent criteria for the diagnosis of Marfan syndrome

Three international nosologies have been proposed for the diagnosis of Marfan syndrome (MFS): the Berlin nosology in 1988; the Ghent nosology in 1996 (Ghent-1); and the revised Ghent nosology in 2010 (Ghent-2). We reviewed the literature and discussed the challenges and concepts of diagnosing MFS in adults. Ghent-1 proposed more stringent clinical criteria, which led to the confirmation of MFS in only 32%-53% of patients formerly diagnosed with MFS according to the Berlin nosology. Conversely, both the Ghent-1 and Ghent-2 nosologies diagnosed MFS, and both yielded similar frequencies of MFS in persons with a causative FBN1 mutation (90% for Ghent-1 versus 92% for Ghent-2) and in persons not having a causative FBN1 mutation (15% versus 13%). Quality criteria for diagnostic methods include objectivity, reliability, and validity. However, the nosology-based diagnosis of MFS lacks a diagnostic reference standard and, hence, quality criteria such as sensitivity, specificity, or accuracy cannot be assessed. Medical utility of diagnosis implies congruency with the historical criteria of MFS, as well as with information about the etiology, pathogenesis, diagnostic triggers, prognostic triggers, and potential complications of MFS. In addition, social and psychological utilities of diagnostic criteria include acceptance by patients, patient organizations, clinicians and scientists, practicability, costs, and the reduction of anxiety. Since the utility of a diagnosis or exclusion of MFS is context-dependent, prioritization of utilities is a strategic decision in the process of nosology development. Screening tests for MFS should be used to identify persons with MFS. To confirm the diagnosis of MFS, Ghent-1 and Ghent-2 perform similarly, but Ghent-2 is easier to use. To maximize the utility of the diagnostic criteria of MFS, a fair and transparent process of nosology development is essential

Development and validation of a novel questionnaire for self-determination of the range of motion of wrist and elbow

Background: The aim of this study was to develop and validate a novel self-administered questionnaire for assessing the patient’s own range of motion (ROM) of the wrist and the elbow. Methods: In a prospective clinical study from January 2015 to June 2015, 101 consecutive patients were evaluated with a novel, self-administered, diagram-based, wrist motion assessment score (W-MAS) and elbow motion assessment score (E-MAS). The questionnaire was statistically evaluated for test-retest reliability, patient-physician agreement, comparison with healthy population, and influence of covariates (age, gender, affected side and involvement in workers’ compensation cases). Results: Assessment of patient-physician agreement demonstrated almost perfect agreement (k > 0.80) with regard to six out of eight items. There was substantial agreement with regard to two items: elbow extension (k = 0.76) and pronation (k = 0.75). The assessment of the test-retest reliability revealed at least substantial agreement (k = 0.70). The questionnaire revealed a high discriminative power when comparing the healthy population with the study group (p = 0.007 or lower for every item). Age, gender, affected side and involvement in workers’ compensation cases did not in general significantly influence the patient-physician agreement for the questionnaire. Conclusion: The W-MAS and E-MAS are valid and reliable self-administered questionnaires that provide a high level of patient-physician agreement for the assessments of wrist and elbow ROM. Level of evidence: Diagnostic study, Level I

Mitral valve prolapse syndrome and MASS phenotype: stability of aortic dilatation but progression of mitral valve prolapse

AbstractBackgroundMitral valve prolapse syndrome (MVPS) and MASS phenotype (MASS) are Marfan-like syndromes that exhibit aortic dilatation and mitral valve prolapse. Unlike in Marfan syndrome (MFS), the presence of ectopia lentis and aortic aneurysm preclude diagnosis of MVPS and MASS. However, it is unclear whether aortic dilatation and mitral valve prolapse remain stable in MVPS or MASS or whether they progress like in MFS.MethodsThis retrospective longitudinal observational study examines clinical characteristics and long-term prognosis of 44 adults with MVPS or MASS (18 men, 26 women aged 38±17years) as compared with 81 adults with Marfan syndrome (MFS) with similar age and sex distribution. The age at final contact was 42±15years with mean follow-up of 66±49months.ResultsAt baseline, ectopia lentis and aortic sinus aneurysm were absent in MVPS and MASS, and systemic scores defined by the revised Ghent nosology were lower than in MFS (all P<.001). Unlike in MFS, no individual with MVPS and MASS developed aortic complications (P<.001). In contrast, the incidence of endocarditis (P=.292), heart failure (P=.644), and mitral valve surgery (P=.140) was similar in all syndromes. Cox regression analysis identified increased LV end-diastolic (P=.013), moderate MVR (P=.019) and flail MV leaflet (P=.017) as independent predictors of mitral valve surgery.ConclusionsThe study provides evidence that MVPS and MASS are Marfan-like syndromes with stability of aortic dilatation but with progression of mitral valve prolapse. Echocardiographic characteristics of mitral valve disease rather than the type of syndrome, predict clinical progression of mitral valve prolapse

Heart failure outcomes according to heart rate and effects of empagliflozin in patients of the EMPEROR-Preserved trial

Aims Empagliflozin reduces cardiovascular death (CVD) or heart failure hospitalization (HHF) in patients with heart failure and preserved ejection fraction (HFpEF). Treatment effects and safety in relation to resting heart rate (RHR) have not been studied. Methods and results The interplay of RHR and empagliflozin effects in EMPEROR-Preserved was evaluated. We grouped patients (n = 5988) according to their baseline RHR (75 bpm [n = 1736]) and explored the influence of RHR on CVD or HHF (primary outcome) and its components in sinus rhythm or atrial fibrillation/flutter (AF) and adverse events. We studied the efficacy of empagliflozin across the RHR spectrum. Compared to placebo, empagliflozin did not change heart rate over time. The primary outcome (p for trend = 0.0004) and its components CVD (p trend = 0.0002), first HHF (p for trend = 0.0099) and all-cause death (p <  0.0001) increased with RHR only in sinus rhythm but not AF. The risk increase with RHR was similar in patients with heart failure and mildly reduced ejection fraction (left ventricular ejection fraction [LVEF] 40–49%) and HFpEF (LVEF ≥50%). Baseline RHR had no influence on the effect of empagliflozin on the primary outcomes (p for trend = 0.20), first HHF (p for trend = 0.49). There were no clinically relevant differences in adverse events between empagliflozin and placebo across the RHR groups. Conclusion Resting heart rate associates with outcomes only in sinus rhythm but not in AF. Empagliflozin reduced outcomes over the entire RHR spectrum without increase of adverse events

Liver tests, cardiovascular outcomes and effects of empagliflozin in patients with heart failure and preserved ejection fraction: The EMPEROR-Preserved trial

Aim The prognostic implication of elevated liver tests in heart failure with preserved ejection fraction (HFpEF) is uncertain. This analysis investigates the association of liver markers with hospitalization for heart failure (HHF) and cardiovascular death (CVD), and the treatment effect of empagliflozin across the range of liver marker levels. Methods and results The double-blind, placebo-controlled EMPEROR-Preserved (EMPagliflozin outcomE tRial in Patients With chrOnic heaRt Failure with Preserved Ejection Fraction) enrolled 5988 patients with HFpEF (ejection fraction >40%). Patients in New York Heart Association class II–IV and elevated N-terminal pro-B-type natriuretic peptide were randomized to receive empagliflozin 10 mg daily or placebo in addition to usual therapy. Patients with significant liver disease were excluded. The primary endpoint was time to first adjudicated HHF or CVD. We explored the association of liver function abnormalities with heart failure outcomes in patients on placebo, the effects of empagliflozin on liver tests and the treatment effects of empagliflozin on heart failure outcomes across categories of liver laboratory values. High alkaline phosphatase (p trend < 0.0001), low albumin (p trend < 0.0001) and high bilirubin (p = 0.02) were associated with poorer outcomes for HHF or CVD, while high aspartate aminotransferase was not, and high alanine aminotransferase was associated with better outcomes. Empagliflozin had no significant effects on liver tests compared to placebo except for albumin which was significantly increased. The treatment effect of empagliflozin on outcomes was not modified by liver tests. Conclusion Abnormalities of liver function tests are associated differently with heart failure outcomes. Salutary effects of empagliflozin on liver tests were not observed although albumin increased. The treatment benefits of empagliflozin were not affected by baseline values of liver parameters

Interleukin-7 Links T Lymphocyte and Intestinal Epithelial Cell Homeostasis

Interleukin-7 (IL-7) is a major survival factor for mature T cells. Therefore, the degree of IL-7 availability determines the size of the peripheral T cell pool and regulates T cell homeostasis. Here we provide evidence that IL-7 also regulates the homeostasis of intestinal epithelial cells (IEC), colon function and the composition of the commensal microflora. In the colon of T cell-deficient, lymphopenic mice, IL-7-producing IEC accumulate. IEC hyperplasia can be blocked by IL-7-consuming T cells or the inactivation of the IL-7/IL-7R signaling pathway. However, the blockade of the IL-7/IL-7R signaling pathway renders T cell-deficient mice more sensitive to chemically-induced IEC damage and subsequent colitis. In summary, our data demonstrate that IL-7 promotes IEC hyperplasia under lymphopenic conditions. Under non-lymphopenic conditions, however, T cells consume IL-7 thereby limiting IEC expansion and survival. Hence, the degree of IL-7 availability regulates both, T cell and IEC homeostasis