Messung der elektrischen Feldstärke in einer Gasentladung mittels Doppler-freier optogalvanischer Spektroskopie unter Verwendung von Laserdioden

A new highly-sensitive method for the detection of the local electric field strength in hydrogen discharges is presented in this Thesis. This method is ideally suited for systems with low electric field strength. Using the intermodulated optogalvanic spectroscopy, Doppler-free spectra of the first Balmer line of Hydrogen were taken in the cathode fall of a low pressure glow discharge. Once the theoretical splitting is known, the electric field strength can be determined from the position of the Doppler-free Stark components of the hydrogen Balmer alpha line. To obtain the electric field strength these profiles were fitted to the Doppler-free optogalvanic spectra. It has been shown for the first time that by using the Doppler-free intermodulated optogalvanic spectroscopy isolated Stark components may be measured. This novel technique is a key development for the investigation of low electric field strengths in low pressure glow discharges

Fragment-to-Lead Medicinal Chemistry Publications in 2018

This Perspective, the fourth in an annual series, summarizes fragment-to-lead (F2L) success stories published during 2018. Topics such as target class, screening methods, physicochemical properties, and ligand efficiency are discussed for the 2018 examples as well as for the combined 111 F2L examples covering 2015-2018. While the overall properties of fragments and leads have remained constant, a number of new trends are noted, for example, broadening of target class coverage and application of FBDD to covalent inhibitors. Moreover, several studies make use of fragment hits that were previously described in the literature, illustrating that fragments are versatile starting points that can be optimized to structurally diverse leads. By focusing on success stories, the hope is that this Perspective will identify and inform best practices in fragment-based drug discovery.</p

Selective and highly efficient dye scavenging by a pH-responsive molecular hydrogelator

A structurally simple low molecular weight hydrogelator derived from isophthalic acid forms robust pH-responsive hydrogels capable of highly efficient and selective dye adsorption

Dissecting the role of distinct OCT4-SOX2 heterodimer configurations in pluripotency

The transcription factors OCT4 and SOX2 are required for generating induced pluripotent stem cells (iPSCs) and for maintaining embryonic stem cells (ESCs). OCT4 and SOX2 associate and bind to DNA in different configurations depending on the arrangement of their individual DNA binding elements. Here we have investigated the role of the different OCT4-SOX2-DNA assemblies in regulating and inducing pluripotency. To this end, we have generated SOX2 mutants that interfere with specific OCT4-SOX2 heterodimer configurations and assessed their ability to generate iPSCs and to rescue ESC self-renewal. Our results demonstrate that the OCT4-SOX2 configuration that dimerizes on a Hoxb1-like composite, a canonical element with juxtaposed individual binding sites, plays a more critical role in the induction and maintenance of pluripotency than any other OCT4-SOX2 configuration. Overall, the results of this study provide new insight into the protein interactions required to establish a de novo pluripotent network and to maintain a true pluripotent cell fate.Link_to_subscribed_fulltex

Multiparametric early detection and prediction of cardiotoxicity using myocardial strain, T1 and T2 mapping, and biochemical markers: A longitudinal cardiac resonance imaging study during 2 years of follow-up

BACKGROUND: Our goal was to evaluate the ability of cardiovascular magnetic resonance for detecting and predicting cardiac dysfunction in patients receiving cancer therapy. Left ventricular ejection fraction, global and regional strain utilizing fast-strain-encoded, T1 and T2 mapping, and cardiac biomarkers (troponin and BNP [brain natriuretic peptide]) were analyzed. METHODS: Sixty-one patients (47 with breast cancer, 11 with non-Hodgkin lymphoma, and 3 with Hodgkin lymphoma) underwent cardiovascular magnetic resonance scans at baseline and at regular intervals during 2 years of follow-up. The percentage of all left ventricular myocardial segments with strain ≤-17% (normal myocardium [%]) was analyzed. Clinical cardiotoxicity (CTX) and sub-CTX were defined according to standard measures. RESULTS: Nine (15%) patients developed CTX, 26 (43%) had sub-CTX. Of the 35 patients with CTX or sub-CTX, 24 (69%) were treated with cardioprotective medications and showed recovery of cardiac function. The amount of normal myocardium (%) exhibited markedly higher accuracy for the detection of CTX and sub-CTX compared with left ventricular ejection fraction, T1, and T2 mapping as well as troponin I (Δareas under the curve=0.20, 0.24, and 0.46 for normal myocardium (%) versus left ventricular ejection fraction, troponin I, and T1 mapping, CONCLUSIONS: Normal myocardium (%) derived by fast-strain-encoded cardiovascular magnetic resonance, is an accurate and sensitive tool that can establish cardiac safety in patients with cancer undergoing cardiotoxic chemotherapy not only for the early detection but also for the prediction of those at risk of developing CTX. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03543228

Zfp296 Is a Novel, Pluripotent-Specific Reprogramming Factor

Expression of the four transcription factors Oct4, Sox2, Klf4, and c-Myc (OSKM) is sufficient to reprogram somatic cells into induced pluripotent stem (iPSCs). However, this process is slow and inefficient compared with the fusion of somatic cells with embryonic stem cells (ESCs), indicating that ESCs express additional factors that can enhance the efficiency of reprogramming. We had previously developed a method to detect and isolate early neural induction intermediates during the differentiation of mouse ESCs. Using the gene expression profiles of these intermediates, we identified 23 ESC-specific transcripts and tested each for the ability to enhance iPSC formation. Of the tested factors, zinc finger protein 296 (Zfp296) led to the largest increase in mouse iPSC formation. We confirmed that Zfp296 was specifically expressed in pluripotent stem cells and germ cells. Zfp296 in combination with OSKM induced iPSC formation earlier and more efficiently than OSKM alone. Through mouse chimera and teratoma formation, we demonstrated that the resultant iPSCs were pluripotent. We showed that Zfp296 activates transcription of the Oct4 gene via the germ cell–specific conserved region 4 (CR4), and when overexpressed in mouse ESCs leads to upregulation of Nanog expression and downregulation of the expression of differentiation markers, including Sox17, Eomes, and T, which is consistent with the observation that Zfp296 enhances the efficiency of reprogramming. In contrast, knockdown of Zfp296 in ESCs leads to the expression of differentiation markers. Finally, we demonstrated that expression of Zfp296 in ESCs inhibits, but does not block, differentiation into neural cells

Relationship between quality of life indicators and cardiac status indicators in chemotherapy patients

AIM: With the aim of improving personalized treatment of patients on chemotherapy, the objective of the study was to assess the degree of association between selected Quality of life (QoL) indicators and both clinical and imaging cardiac status indicators when detecting deterioration in QoL of these patients. METHODS: In a cohort clinical study in Hamburg, from August 2017 through October 2020, 59 cancer patients, aged 18-80 years, were evaluated before chemotherapy, and at several follow-ups, using EQ-5D and SF-36 QoL questionnaires, fast strain-encoded (fast-SENC) cardiac magnetic resonance (CMR), conventional CMR, and echocardiography, and further received a clinical and biomarker examination. Data was analyzed using survival analyses. A decline of more than 5% in each observed QoL metric value was defined as the observed event. Patient were separated into groups according to the presentation of cardiotoxicity as per its clinical definition, the establishment of the indication for cardioprotective therapy initiation, and by a worsening in the value of each observed imaging metric by more than 5% in the previous follow-up compared to the corresponding pre-chemotherapy baseline value. RESULTS: Among clinical cardiac status indicators, the indication for cardioprotective therapy showed statistically good association with QoL scores (EQ-5D p=0.028; SF-36 physical component p=0.016; SF-36 mental component p=0.012). In terms of imaging metrics, the MyoHealth segmental myocardial strain score was the only one demonstrating consistently good QoL score association (EQ-5D p=0.005; SF-36 physical component p=0.056; SF-36 mental component p=0.002). CONCLUSIONS: Established fast-SENC CMR scores are capable of highlighting patients with reduced QoL, who require more frequent/optimal management

Changing POU dimerization preferences converts Oct6 into a pluripotency inducer

� 2016 The Authors. Published under the terms of the CC BY 4.0 license The transcription factor Oct4 is a core component of molecular cocktails inducing pluripotent stem cells (iPSCs), while other members of the POU family cannot replace Oct4 with comparable efficiency. Rather, group III POU factors such as Oct6 induce neural lineages. Here, we sought to identify molecular features determining the differential DNA-binding and reprogramming activity of Oct4 and Oct6. In enhancers of pluripotency genes, Oct4 cooperates with Sox2 on heterodimeric SoxOct elements. By re-analyzing ChIP-Seq data and performing dimerization assays, we found that Oct6 homodimerizes on palindromic OctOct more cooperatively and more stably than Oct4. Using structural and biochemical analyses, we identified a single amino acid directing binding to the respective DNA elements. A change in this amino acid decreases the ability of Oct4 to generate iPSCs, while the reverse mutation in Oct6 does not augment its reprogramming activity. Yet, with two additional amino acid exchanges, Oct6 acquires the ability to generate iPSCs and maintain pluripotency. Together, we demonstrate that cell type-specific POU factor function is determined by select residues that affect DNA-dependent dimerization.Link_to_subscribed_fulltex