The oxidized bile acid 7-oxoLCA (7-oxolithocholic acid), formed primarily by gut micro-organisms, is reduced in human liver to CDCA (chenodeoxycholic acid) and, to a lesser extent, UDCA (ursodeoxycholic acid). The enzyme(s) responsible remained unknown. Using human liver microsomes, we observed enhanced 7-oxoLCA reduction in the presence of detergent. The reaction was dependent on NADPH and stimulated by glucose 6-phosphate, suggesting localization of the enzyme in the ER (endoplasmic reticulum) and dependence on NADPH-generating H6PDH (hexose-6-phosphate dehydrogenase). Using recombinant human 11β-HSD1 (11β-hydroxysteroid dehydrogenase 1), we demonstrate efficient conversion of 7-oxoLCA into CDCA and, to a lesser extent, UDCA. Unlike the reversible metabolism of glucocorticoids, 11β-HSD1 mediated solely 7-oxo reduction of 7-oxoLCA and its taurine and glycine conjugates. Furthermore, we investigated the interference of bile acids with 11β-HSD1-dependent interconversion of glucocorticoids. 7-OxoLCA and its conjugates preferentially inhibited cortisone reduction, and CDCA and its conjugates inhibited cortisol oxidation. Three-dimensional modelling provided an explanation for the binding mode and selectivity of the bile acids studied. The results reveal that 11β-HSD1 is responsible for 7-oxoLCA reduction in humans, providing a further link between hepatic glucocorticoid activation and bile acid metabolism. These findings also suggest the need for animal and clinical studies to explore whether inhibition of 11β-HSD1 to reduce cortisol levels would also lead to an accumulation of 7-oxoLCA, thereby potentially affecting bile acid-mediated functions.

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The phase diagram Li−Mg−N−H offers ample opportunities for potential hydrogen storage systems. Three systems based on lithium nitride, Li 3 N, were investigated by time-resolved in situ methods (thermal analysis, Xray and neutron diffraction) at temperatures up to 703 K and hydrogen gas pressures up to 9.4 MPa. Pure lithium nitride reacts in a one-step reaction to lithium amide according to Li 3 N + 2H 2 → LiNH 2 + 2LiH at 1.0 MPa hydrogen pressure. Equimolar mixtures of lithium nitride with magnesium hydride, both at 1.5 and 9.4 MPa hydrogen gas pressure, react in the same way up to 543 K, i.e., magnesium hydride does not participate in the reaction. At higher temperatures, lithium magnesium nitride is formed according to the endothermic reaction LiNH 2 + MgH 2 → LiMgN + 2H 2 at moderate (≤1.5 MPa) and via the exothermic reaction Li 3 N + MgH 2 → LiMgN + 2LiH at higher hydrogen gas pressures (5.0 MPa). Mixed imide Li 2 Mg(NH) 2 is formed when an excess of Li 3 N is used in the reaction. The hydrogenation of mixtures of lithium nitride with magnesium starts with the formation Li 2 NH and Li 4 NH, followed by the mixed imide Li 2 Mg(NH) 2 at higher temperatures and finally the formation of Mg 3 N 2 and LiH. Deuterides react accordingly.

Human recombinant granulocyte colony stimulating factor (rhG-CSF) is widely used in hematology and oncology for the treatment of neutropenia, for the restoration of neutrophil production after bone marrow transplantation, for myelodysplastic syndromes, and aplastic anemia. The E. coli expression system is commonly used for fast recombinant production of rhG-CSF at a large scale. We have applied a novel autoinduction method for the batch expression of rhG-CSF to study whether this new system would increase cell mass and target-protein yield compared to conventional E. coli cell culture and induction with isopropyl β-D-thiogalactopyranoside (IPTG). We could demonstrate 3-fold higher culture densities and a 5-fold higher protein yield compared to IPTG induction without the need to monitor cell growth in a shortened 24 h expression procedure. rhG-CSF expressed in autoinduction media was successfully extracted from E. coli inclusion bodies and refolded by dialysis. After size exclusion chromatography (SEC) purification, rhG-CSF showed similar conformation, biological activity and aggregation profile compared to the commercially available biosimilar TEVAgrastim(®) (TEVA Pharma AG). Expression by autoinduction is suggested as a cost- and time-effective method for rhG-CSF production.

Formulation of nanoparticulate DNA vaccines requires the assessment of stability and integrity of the components implicated. Stability of cationic nanoparticles made of N-trimethyl chitosan and chondroitin sulfate (TMC nanoparticles) was investigated in aqueous solution and after freeze-drying by characterization of their size, polydispersity index (PDI), and zeta potential. Furthermore, the structural integrity of plasmid DNA (pDNA) on adsorption to the nanoparticle surface was investigated. Agarose gel electrophoresis showed DNA retention when applied with the nanocarrier, suggesting that pDNA adsorption on nanoparticles took place. In circular dichroism (CD) spectra, ellipticity of pDNA decreased at 280 nm and increased at 245 nm, and the maximum wavelength shifted from 275 nm to 285 nm when nanoparticles were present. Once released from the particles, the secondary structure of the plasmid was retained in its native form. pDNA release from pDNA-TMC nanoparticles was indicated by a rise in zeta potential from initially -32 mV (pDNA adsorbed to particles) to 14 mV during one hour, and to 36 mV after 24 hours. Unloaded TMC nanoparticles remained stable in suspension for 24 hours, maintaining diameters of around 200 nm, and zeta potential values of approximately 38 mV. Freeze-drying with sucrose could ensure storage for 30 days, with minimal increase in size (291 nm) and charge (62 mV). In conclusion, TMC nanoparticles may potentially be freeze-dried in the presence of sucrose to be stored for prolonged periods of time. Furthermore, pDNA was successfully adsorbed to the cationic nanoparticles and remained intact after being released.

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Mixed crystal Laves phases Ln1–xEuxMg2 (Ln = La, Sm) were prepared from the elements by melting reactions and characterized by X‐ray powder diffraction. In the substitutional range 0 ≤ x ≤ 0.5 cubic Laves phases of the MgCu2 type, for 0.8 ≤ x ≤ 1 (Ln = La) and 0.9 ≤ x ≤ 1 (Ln = Sm), respectively, hexagonal Laves phases of the MgZn2 type are formed, separated from each other by a miscibility gap. The dependence of the lattice parameters on the degree of substitution x follows closely a Vegard type behavior with a(La1–xEuxMg2 (0 ≤ x ≤ 0.5)) = (8.798(3) + 0.00177(8)x) Å and a(Sm1–xEuxMg2 (0 ≤ x ≤ 0.5)) = (8.629(2) + 0.00404(7)x) Å. Analysis of the unit cell volumes suggests europium to be divalent in all mixed Laves phases. Hydrogenation of the Laves phases as followed by in situ thermal analysis is exothermic for all compositions. For the hexagonal europium rich Laves phases the reaction products upon hydrogenation at 6 MPa hydrogen pressure in an autoclave are binary lanthanum hydride and EuMg2H6, the latter being unsubstituted according to lattice parameters refined by Rietveld analysis. For lanthanum‐rich compounds (0 ≤ x ≤ 0.1) ternary hydrides of the tetragonal LaMg2D7 type structure are formed, if the hydrogen pressure is high enough (11 MPa), and heating rates and reaction temperatures are kept low (373 K). The crystal structure of the new hydride La0.9Eu0.1Mg2Hy≤7 was refined from X‐ray powder diffraction data by Rietveld analysis (space group P41212, a = 6.2592(1) Å, c = 9.3759(3) Å, V = 367.322(2) Å3, Z = 4).

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