Sulindac sulfide reverses aberrant self-renewal of progenitor cells induced by the AML-associated fusion proteins PML/RARalpha and PLZF/RARalpha

Chromosomal translocations can lead to the formation of chimeric genes encoding fusion proteins such as PML/RARalpha, PLZF/RARalpha, and AML-1/ETO, which are able to induce and maintain acute myeloid leukemia (AML). One key mechanism in leukemogenesis is increased self renewal of leukemic stem cells via aberrant activation of the Wnt signaling pathway. Either X-RAR, PML/RARalpha and PLZF/RARalpha or AML-1/ETO activate Wnt signaling by upregulating gamma-catenin and beta-catenin. In a prospective study, a lower risk of leukemia was observed with aspirin use, which is consistent with numerous studies reporting an inverse association of aspirin with other cancers. Furthermore, a reduction in leukemia risk was associated with use of non-steroidal anti-inflammatory drug (NSAID), where the effects on AML risk was FAB subtype-specific. To better investigate whether NSAID treatment is effective, we used Sulindac Sulfide in X-RARalpha-positive progenitor cell models. Sulindac Sulfide (SSi) is a derivative of Sulindac, a NSAID known to inactivate Wnt signaling. We found that SSi downregulated both beta-catenin and gamma-catenin in X-RARalpha-expressing cells and reversed the leukemic phenotype by reducing stem cell capacity and increasing differentiation potential in X-RARalpha-positive HSCs. The data presented herein show that SSi inhibits the leukemic cell growth as well as hematopoietic progenitors cells (HPCs) expressing PML/RARalpha, and it indicates that Sulindac is a valid molecular therapeutic approach that should be further validated using in vivo leukemia models and in clinical settings

Quantenchemische Behandlung von elektronischem Energietransfer

Im Rahmen dieser Dissertation wurden quantenchemische Untersuchungen zum Phänomen des elektronischen Energietransfers durchgeführt. Zum einen wurden theoretische Modelle zur Berücksichtigung temperaturabhängiger Elektron-Phonon-Kopplung in vibronischen Spektren ausgearbeitet und numerischen Tests unterzogen. Zum anderen erfolgte die Bestimmung molekularer Eigenschaften bichromophorer Systeme unter Anwendung etablierter Rechenmethoden. Im Fokus stehen das Zusammenspiel elektronischer Kopplung und statischer Unordnung sowie Energietransferzeiten und der Einfluss molekularer Brücken in Dimeren auf die Kopplung. Da sich elektronischer Energietransfer spektroskopisch nachweisen lässt, wurden temperaturabhängige Simulationen der Linienform von vibronischen Übergängen, die an ein Wärmebad ankoppeln, durchgeführt. Die erforderliche Antwortfunktion zur Bestimmung der spektralen Linienform kann aus einer Kumulantenentwicklung und alternativ aus der Multi-Level Redfieldtheorie abgeleitet werden. Statt der genäherten Schwingungsstruktur des Brownschen Oszillatormodells wurde eine explizit berechnete Zustandsdichte als Ausgangspunkt verwendet. Sowohl reine Elektron-Phonon- als auch Schwingung-Phonon-Kopplung werden für verschiedene Spektraldichten der Badmoden diskutiert. Im Zuge eines Kooperationsprojekts führten wir Untersuchungen zur elektronischen Kopplung an einer homologen Reihe von Rylendimeren mit unterschiedlichen Brückenlängen durch. Zu diesem Zweck wurden Ergebnisse aus Tieftemperatureinzelmolekülmessungen und quantenchemischen Berechnungen auf Grundlage des vibronischen Kopplungsmodells herangezogen und ausgewertet. Die untersuchten Dimere zeigen einen Übergang vom Grenzfall starker Kopplung hin zu schwacher Kopplung und die mittleren Energietransferzeiten konnten in guter Übereinstimmung mit experimentellen Messwerten berechnet werden. Da eine molekulare Brücke zwischen Donor- und Akzeptoreinheit die elektronische Kopplung modifiziert, kann sie sich störend auf experimentelle Messungen auswirken. Daher wurde untersucht, ob das interchromophore Kopplungsverhalten vorwiegend durch die Polarisierbarkeit des verbrückenden Elements oder durch bindungsvermittelte Wechselwirkungen beeinflusst wird und welche Brückentypen sich folglich für experimentelle Studien eignen. Sämtliche untersuchten Brückenelemente führten zu einer Vergrößerung der elektronischen Kopplung und die Kopplungsstärke wurde maßgeblich durch brückenvermittelte Wechselwirkungen bestimmt.This thesis includes quantum chemical studies concerning the phenomenon of electronic excitation energy transfer. Theoretical models treating temperature-dependent electron-phonon coupling in vibronic spectra were presented and numerically tested. Furthermore molecular properties of bichromophoric systems were calculated using well-established methods. We focus on the interplay of electronic coupling and static disorder as well as energy transfer times and the influence of molecular bridges in dimers on the coupling. As electronic energy transfer is detectable using spectroscopic methods, temperature-dependent simulations of the line shape of vibronic transitions, coupled to a heat bath, were carried out. The required response function to determine the spectral line shape can be extracted from a cumulant expansion or alternatively from the generalized Redfield theory. Our starting point was a calculated density of states instead of the approximated vibronic structure within the Brownian oscillator model. Both pure electron-phonon coupling and vibration-phonon coupling are discussed for various spectral densities of the bath modes. In the course of a cooperation project we studied the electronic coupling in a homologous series of bridged rylene dimers with different interchromophoric distances. Results of low-temperature single molecule measurements and quantum chemical calculations based on a vibronic coupling model were interpreted, simultaneously. The reviewed dimers show a transition from strong to weak coupling as limiting cases and the averaged energy transfer times could be calculated in good agreement with experimental findings. As a molecular bridge between donor and acceptor unit modifies the electronic coupling, it can influence experimental measurements. Thus, we analyzed the effect of the polarizability of the bridge and through-bond interactions on the interchromophoric coupling to find appropriate types of spacers for experimental studies. All investigated types of bridges led to enhanced electronic couplings while the coupling strengths mainly were determined by bridge-mediated interactions.150 S

Mamão minimamente processado em diferentes cortes

O objetivo deste trabalho foi avaliar as características químicas do mamão formosa após a realização do processamento mínimo, utilizando diferentes tipos de cortes. Primeiramente o mamão foi limpo, retirou-se a casca e efetuou-se dois tipos de corte, em cubos grandes e cubos pequenos. Parte do mamão foi moido para realizar as análises do teor de grau brix, acidez titulável e pH. A outra parte separada conforme o tipo de corte foi acomodada em uma embalagem, cada amostra foi pesada e levada para armazenamento em geladeira por um período de 21 dias, mantendo o ambiente controlado. Após esse período realizou-se novamente as análises e foi obtido os resultados. O tipo de corte teve influência nos resultados, sendo que o corte em cubos  grandes tevemaior teor de grau brix, menor acidez titulável e maior perda de massa após os 21 dias e não houve diferenciação quanto ao pH

Evaluation of a newly developed flipped-classroom course on interprofessional practice in health care for medical students

Interprofessional education is expected to promote collaborative practice and should therefore be included in health professionals’ curricula. Reports on interprofessional curricular development and its evaluation are rare. We therefore undertook a comprehensive quantitative and qualitative evaluation of a new, mandatory course on interprofessional collaboration for medical students during their third year of the Bachelor of Medicine study programme. The newly developed and implemented course spans over six weeks and was designed in a hybrid, flipped-classroom format. It incorporates experience- and case-based learning as well as interactions with other health professionals. Each student completes an eLearning and a clinical workshadowing individually before attending the – due to the pandemic – virtual live lectures. To assess quality and usefulness of teaching-learning formats and course structure to learn about interprofessional collaboration and to develop interprofessional competencies and identity, a quantitative and qualitative evaluation was performed with more than 280 medical students and 26 nurse educators from teaching hospitals using online surveys (open & closed-ended format). Data were analyzed descriptively and using content analysis processes. Students appreciated the flipped-classroom concept, the real-world case-based learning scenarios with interprofessional lecturer teams, and the possibility of an experience-based learning opportunity in the clinical setting including interaction with students and professionals from other health professions. Interprofessional identity did not change during the course. Evaluation data showed that the course is a promising approach for teaching-learning interprofessional competencies to medical students. The evaluation revealed three factors that determined the success of this course, namely, a flipped-classroom concept, the individual workshadowing of medical students with another health professional, mainly nurses, and live sessions with interprofessional teaching-learning teams. The course structure and teaching-learning methods showed potential and could serve as a template for interprofessional course development in other institutions and on other course topics

Pregnancy in patients with the Fontan operation

Improved survival rates for patients with a Fontan circulation has allowed more women with this complex cardiac physiology to contemplate pregnancy. However, pregnancy in women with a Fontan circulation is associated with a high risk of adverse maternal and foetal outcomes, high rates of miscarriage, and preterm delivery. Factors associated with a successful pregnancy outcome are younger age, normal body weight, absence of significant functional limitation, no Fontan-related complications, and well-functioning single ventricle physiology. Appropriate care with timely preconception counselling and regular, frequent clinical reviews by a multidisciplinary team based at a tertiary centre improves the chance of a successful pregnancy. Empowerment of patients with education on their specific congenital cardiac condition and its projected trajectory helps them make informed choices regarding their health, reproductive choices, and assists them to achieve their life goals.</p

A time-stratified, case–crossover study of heat exposure and perinatal mortality from 16 hospitals in sub-Saharan Africa

Growing evidence suggests that extreme heat events affect both pregnant women and their infants, but few studies are available from sub-Saharan Africa. Using data from 138,015 singleton births in 16 hospitals in Benin, Malawi, Tanzania and Uganda, we investigated the association between extreme heat and early perinatal deaths, including antepartum and intrapartum stillbirths, and deaths within 24 h after birth using a time-stratified case–crossover design. We observed an association between an increase from the 75th to the 99th percentile in mean temperature 1 week (lag 0–6 d) before childbirth and perinatal mortality (odds ratio (OR) = 1.34 (95% confidence interval (CI) 1.01–1.78)). The estimates for stillbirths were similarly positive, but CIs included unity: OR = 1.29 (95% CI 0.95–1.77) for all stillbirths, OR = 1.18 (95% CI 0.71–1.95) for antepartum stillbirths and OR = 1.64 (95% CI 0.74–3.63) for intrapartum stillbirths. The cumulative exposure–response curve suggested that the steepest slopes for heat for intrapartum stillbirths and associations were stronger during the hottest seasons. We conclude that short-term heat exposure may increase mortality risks, particularly for intrapartum stillbirths, raising the importance of improved intrapartum care

SH3TC2, a protein mutant in Charcot-Marie-Tooth neuropathy, links peripheral nerve myelination to endosomal recycling

Patients with Charcot-Marie-Tooth neuropathy and gene targeting in mice revealed an essential role for the SH3TC2 gene in peripheral nerve myelination. SH3TC2 expression is restricted to Schwann cells in the peripheral nervous system, and the gene product, SH3TC2, localizes to the perinuclear recycling compartment. Here, we show that SH3TC2 interacts with the small guanosine triphosphatase Rab11, which is known to regulate the recycling of internalized membranes and receptors back to the cell surface. Results of protein binding studies and transferrin receptor trafficking are in line with a role of SH3TC2 as a Rab11 effector molecule. Consistent with a function of Rab11 in Schwann cell myelination, SH3TC2 mutations that cause neuropathy disrupt the SH3TC2/Rab11 interaction, and forced expression of dominant negative Rab11 strongly impairs myelin formation in vitro. Our data indicate that the SH3TC2/Rab11 interaction is relevant for peripheral nerve pathophysiology and place endosomal recycling on the list of cellular mechanisms involved in Schwann cell myelinatio

Novel insights into PORCN mutations, associated phenotypes and pathophysiological aspects.

BACKGROUND: Goltz syndrome (GS) is a X-linked disorder defined by defects of mesodermal- and ectodermal-derived structures and caused by PORCN mutations. Features include striated skin-pigmentation, ocular and skeletal malformations and supernumerary or hypoplastic nipples. Generally, GS is associated with in utero lethality in males and most of the reported male patients show mosaicism (only three non-mosaic surviving males have been described so far). Also, precise descriptions of neurological deficits in GS are rare and less severe phenotypes might not only be caused by mosaicism but also by less pathogenic mutations suggesting the need of a molecular genetics and functional work-up of these rare variants. RESULTS: We report two cases: one girl suffering from typical skin and skeletal abnormalities, developmental delay, microcephaly, thin corpus callosum, periventricular gliosis and drug-resistant epilepsy caused by a PORCN nonsense-mutation (c.283C > T, p.Arg95Ter). Presence of these combined neurological features indicates that CNS-vulnerability might be a guiding symptom in the diagnosis of GS patients. The other patient is a boy with a supernumerary nipple and skeletal anomalies but also, developmental delay, microcephaly, cerebral atrophy with delayed myelination and drug-resistant epilepsy as predominant features. Skin abnormalities were not observed. Genotyping revealed a novel PORCN missense-mutation (c.847G > C, p.Asp283His) absent in the Genome Aggregation Database (gnomAD) but also identified in his asymptomatic mother. Given that non-random X-chromosome inactivation was excluded in the mother, fibroblasts of the index had been analyzed for PORCN protein-abundance and -distribution, vulnerability against additional ER-stress burden as well as for protein secretion revealing changes. CONCLUSIONS: Our combined findings may suggest incomplete penetrance for the p.Asp283His variant and provide novel insights into the molecular etiology of GS by adding impaired ER-function and altered protein secretion to the list of pathophysiological processes resulting in the clinical manifestation of GS