Recent advances in the application of parahydrogen in catalysis and biochemistry

Nuclear Magnetic Resonance (NMR) spectroscopy and Magnetic Resonance Imaging (MRI) are analytical and diagnostic tools that are essential for a very broad field of applications, ranging from chemical analytics, to non-destructive testing of materials and the investigation of molecular dynamics, to in vivo medical diagnostics and drug research. One of the major challenges in their application to many problems is the inherent low sensitivity of magnetic resonance, which results from the small energy-differences of the nuclear spin-states. At thermal equilibrium at room temperature the normalized population difference of the spin-states, called the Boltzmann polarization, is only on the order of 10⁻⁵. Parahydrogen induced polarization (PHIP) is an efficient and cost-effective hyperpolarization method, which has widespread applications in Chemistry, Physics, Biochemistry, Biophysics, and Medical Imaging. PHIP creates its signal-enhancements by means of a reversible (SABRE) or irreversible (classic PHIP) chemical reaction between the parahydrogen, a catalyst, and a substrate. Here, we first give a short overview about parahydrogen-based hyperpolarization techniques and then review the current literature on method developments and applications of various flavors of the PHIP experiment

Gesundheitsökonomische Aspekte in der telemedizinischen Schlaganfall-Akutversorgung: Eine qualitative Analyse

Spezialisierte Stroke Units bieten Schlaganfallpatienten die bestmögliche Behandlung - ihrer flächendeckenden Einrichtung steht allerdings akuter Mangel an erfahrenen Neurologen sowie die geringe Schlaganfallinzidenz in dünnbesiedelten, ländlichen Gebieten entgegen. Hier werden zunehmend telemedizinische Lösungen eingesetzt, um neurologische Expertise in Krankenhäusern der Grund- und Regelversorgung verfügbar zu machen. Nationale und internationale telemedizinische Pilotprojekte haben gezeigt, dass eine fundierte und schnelle Entscheidung über die Thrombolyse als wichtigste Akuttherapie, aber auch über weitere Interventionen telemedizinisch getroffen werden kann. Dabei evaluieren bisherige Studien zwar die Verbesserung der Versorgungsqualität durch die Netzwerke, nicht aber ihre für eine nachhaltige Umsetzung grundlegende Wirtschaftlichkeit. Komplementär zu der medizinischen Evaluation zeigt die hier vorgestellte qualitative ökonomische Bewertung deutscher und amerikanischer telemedizinischer Versorgungskonzepte bezüglich ihrer Geschäfts- und Finanzierungsmodelle klare Unterschiede in der Effizienz und dem langfristig möglichen Erfolg der einzelnen Netzwerkkonzepte. Auffällig ist die konträre Schwerpunktsetzung zwischen zwei großen amerikanischen und den deutschen Netzwerken: Während in den amerikanischen Netzen gezielt Nutzungsanreize geschaffen wurden, die über den immanenten Wunsch der beteiligten Ärzte zur Versorgungsverbesserung hinausgehen, ist dies in den deutschen von sekundärer Bedeutung. Weiterhin sind die deutschen Telemedizinnetzwerke im Unterschied zu einigen amerikanischen tendenziell nicht auf Wachstum angelegt. Aus wirtschaftlicher Sicht bieten dezentral organisierte Netzwerke ein höheres Effizienzpotential als rein lokale, und die Integration von Anreizen in das Geschäftsmodelldesign ist für das langfristige Bestehen vor allem in einem wettbewerbsintensiven Markt ein grundlegender Erfolgsfaktor

Parahydrogen-induced polarization enables the single-scan NMR detection of a 236 kDa biopolymer at nanomolar concentrations

Abstract Nuclear magnetic resonance (NMR) experiments utilizing parahydrogen-induced polarization (PHIP) were performed to elucidate the PHIP activity of the synthetic 236 kDa biopolymer poly-γ-(4-propargyloxy)-benzyl-L-glutamate) (PPOBLG). The homopolypeptide was successfully hyperpolarized and the enhanced signals were detected in 11.7 T solution NMR as a function of the PPOBLG concentration. The hydrogenation with parahydrogen caused signal enhancements of 800 and more for the vinyl protons of the side chain at low substrate concentration. As a result of this high enhancement factor, even at 13 nM of PPOBLG, a single scan 1H-NMR detection of the hyperpolarized protons was possible, owing to the combination of hyperpolarization and density of PHIP active sites

Image1_Innovative in vivo rat model for global cerebral hypoxia: a new approach to investigate therapeutic and preventive drugs.JPEG

Introduction: Severe acute global cerebral hypoxia can lead to significant disability in humans. Although different animal models have been described to study hypoxia, there is no endogenous model that considers hypoxia and its effect on the brain as an independent factor. Thus, we developed a minimally invasive rat model, which is based on the non-depolarizing muscle blocking agent rocuronium in anesthetized animals. This drug causes respiratory insufficiency by paralysis of the striated muscles.Methods: In this study, 14 rats underwent 12 min of hypoxemia with an oxygen saturation of approximately 60% measured by pulse oximetry; thereafter, animals obtained sugammadex to antagonize rocuronium immediately.Results: Compared to controls (14 rats, anesthesia only), hypoxic animals demonstrated significant morphological alterations in the hippocampus (cell decrease in the CA 1 region) and the cerebellum (Purkinje cell decrease), as well as significant changes in hypoxia markers in blood (Hif2α, Il1β, Tgf1β, Tnfα, S100b, cspg2, neuron-specific enolase), hippocampus (Il1β, Tnfα, S100b, cspg2, NSE), and cerebellum (Hif1α, Tnfα, S100b, cspg2, NSE). Effects were more pronounced in females than in males.Discussion: Consequently, this model is suitable to induce hypoxemia with consecutive global cerebral hypoxia. As significant morphological and biochemical changes were proven, it can be used to investigate therapeutic and preventive drugs for global cerebral hypoxia.</p

Image2_Innovative in vivo rat model for global cerebral hypoxia: a new approach to investigate therapeutic and preventive drugs.JPEG

Introduction: Severe acute global cerebral hypoxia can lead to significant disability in humans. Although different animal models have been described to study hypoxia, there is no endogenous model that considers hypoxia and its effect on the brain as an independent factor. Thus, we developed a minimally invasive rat model, which is based on the non-depolarizing muscle blocking agent rocuronium in anesthetized animals. This drug causes respiratory insufficiency by paralysis of the striated muscles.Methods: In this study, 14 rats underwent 12 min of hypoxemia with an oxygen saturation of approximately 60% measured by pulse oximetry; thereafter, animals obtained sugammadex to antagonize rocuronium immediately.Results: Compared to controls (14 rats, anesthesia only), hypoxic animals demonstrated significant morphological alterations in the hippocampus (cell decrease in the CA 1 region) and the cerebellum (Purkinje cell decrease), as well as significant changes in hypoxia markers in blood (Hif2α, Il1β, Tgf1β, Tnfα, S100b, cspg2, neuron-specific enolase), hippocampus (Il1β, Tnfα, S100b, cspg2, NSE), and cerebellum (Hif1α, Tnfα, S100b, cspg2, NSE). Effects were more pronounced in females than in males.Discussion: Consequently, this model is suitable to induce hypoxemia with consecutive global cerebral hypoxia. As significant morphological and biochemical changes were proven, it can be used to investigate therapeutic and preventive drugs for global cerebral hypoxia.</p

Image3_Innovative in vivo rat model for global cerebral hypoxia: a new approach to investigate therapeutic and preventive drugs.JPEG

Introduction: Severe acute global cerebral hypoxia can lead to significant disability in humans. Although different animal models have been described to study hypoxia, there is no endogenous model that considers hypoxia and its effect on the brain as an independent factor. Thus, we developed a minimally invasive rat model, which is based on the non-depolarizing muscle blocking agent rocuronium in anesthetized animals. This drug causes respiratory insufficiency by paralysis of the striated muscles.Methods: In this study, 14 rats underwent 12 min of hypoxemia with an oxygen saturation of approximately 60% measured by pulse oximetry; thereafter, animals obtained sugammadex to antagonize rocuronium immediately.Results: Compared to controls (14 rats, anesthesia only), hypoxic animals demonstrated significant morphological alterations in the hippocampus (cell decrease in the CA 1 region) and the cerebellum (Purkinje cell decrease), as well as significant changes in hypoxia markers in blood (Hif2α, Il1β, Tgf1β, Tnfα, S100b, cspg2, neuron-specific enolase), hippocampus (Il1β, Tnfα, S100b, cspg2, NSE), and cerebellum (Hif1α, Tnfα, S100b, cspg2, NSE). Effects were more pronounced in females than in males.Discussion: Consequently, this model is suitable to induce hypoxemia with consecutive global cerebral hypoxia. As significant morphological and biochemical changes were proven, it can be used to investigate therapeutic and preventive drugs for global cerebral hypoxia.</p

High-resolution analysis of Merkel Cell Polyomavirus in Merkel Cell Carcinoma reveals distinct integration patterns and suggests NHEJ and MMBIR as underlying mechanisms.

Merkel Cell Polyomavirus (MCPyV) is the etiological agent of the majority of Merkel Cell Carcinomas (MCC). MCPyV positive MCCs harbor integrated, defective viral genomes that constitutively express viral oncogenes. Which molecular mechanisms promote viral integration, if distinct integration patterns exist, and if integration occurs preferentially at loci with specific chromatin states is unknown. We here combined short and long-read (nanopore) next-generation sequencing and present the first high-resolution analysis of integration site structure in MCC cell lines as well as primary tumor material. We find two main types of integration site structure: Linear patterns with chromosomal breakpoints that map closely together, and complex integration loci that exhibit local amplification of genomic sequences flanking the viral DNA. Sequence analysis suggests that linear patterns are produced during viral replication by integration of defective/linear genomes into host DNA double strand breaks via non-homologous end joining, NHEJ. In contrast, our data strongly suggest that complex integration patterns are mediated by microhomology-mediated break-induced replication, MMBIR. Furthermore, we show by ChIP-Seq and RNA-Seq analysis that MCPyV preferably integrates in open chromatin and provide evidence that viral oncogene expression is driven by the viral promoter region, rather than transcription from juxtaposed host promoters. Taken together, our data explain the characteristics of MCPyV integration and may also provide a model for integration of other oncogenic DNA viruses such as papillomaviruses