Expanding the 4,4′-bipyridine ligand: Structural variation in {M(pytpy)2}2+ complexes (pytpy = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine,M = Fe,Ni, Ru) and assembly of the hydrogen-bonded,one-dimensional polymer {[Ru(pytpy)(Hpytpy)]}n3n+

The solid state structures of [Ni(1)₂][NO₃]₂ · 2MeOH · 2H₂O, [Fe(1)₂][ClO₄]₂ · 2MeOH · 0.5H₂O, [Ru(1)₂][PF₆]₂ and [Ru(1)₂][PF₆][NO₃] (1 = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine) are presented and the structural variation observed for the {M(1)₂}²⁺ unit is discussed. Protonation of the pendant pyridine group in [Ru(1)₂]²⁺ leads to the formation of a hydrogen-bonded, one-dimensional polymer [{Ru(1)(H1)}_n]³ⁿ⁺ exemplifed by the solid-state structure of [{Ru(1)(H1)}{Fe(NCS)₆} · 1.25H₂O]_n.     

Effects of pioglitazone versus simvastatin on biomarkers of inflammation in patients on high cardiovascular risk

High levels of fetuin-A has been linked to cardiovascular disease, possibly via modulating low-grade systemic inflammation. We performed a subanalysis from the PIOSTAT study to investigate a possible link between fetuin-A and the inflammatory biomarker hs-CRP. 66 nondiabetic individuals at cardiovascular risk were randomized to either pioglitazone, simvastatin, or the combination of both, and followed for 12 weeks. At study endpoint, correlations between serum fetuin-A, hs-CRP, blood lipids, PAI-1, MMP-9, HOMA-IR, and liver transaminases were investigated by Spearman rank correlation. Changes in fetuin-A concentration did not correlate to changes in hs-CRP (r=0.19, p=0.16). A positive correlation was found for change of HOMA-IR value (r=0.33, p=0.01) and for the AST/ALT ratio (p<0.05). Our data suggest that the previously observed correlation between elevated circulating fetuin-A and hs-CRP in epidemiological studies may not reflect a causal relationship in nondiabetic patients on high cardiovascular risk.     

Keto acids in tissues and biological fluids: O-t-butyldimethylsilyl quinoxalinols as derivatives for sensitive gas chromatographic/mass spectrometric determination

Quinoxalinol t-butyldimethylsilyl ethers were prepared from three branched-chain and from two aliphatic unbranched 2-keto acids. The electron impact (EI) mass spectra display pronounced [M-57]+ ions. With 39-51% of total ion current contained within them, sensitivity is greater than on chemical ionization (CI) mass spectrometry of O-trimethylsilyl derivatives. Mass spectra and chromatographic behaviour of these novel keto acid derivatives are discussed and preliminary quantitative data from rat muscle are given.     

Importance of monocytes/macrophages and fibroblasts for healing of micronecroses in porcine myocardium

In porcine heart, embolization of small coronary arteries with microspheres in 25 m in diameter induces collateral capillary vessel growth by angiogenesis in and around focal necrosis. By histological analysis the inflammatory infiltrates in this porcine tissue were characterized by numerous monocytes/macrophages and fibroblasts as well as neutrophils and numerous capillaries, some in mitosis. The aim of the present study, therefore, was to clarify the role of monocytes/macrophages and fibroblasts in angiogenesis and in repair in ischemic porcine myocardium. Using a human acidic fibroblast growth factor (aFGF) cDNA probe forin situ hybridisation labeling for aFGF mRNA was seen in monocytes and macrophages only, beginning at day 1, with a maximum at 3 and 7 days, and minimal labeling at 4 weeks. We have also shown, with a specific antibody and fluorescence microscopy, that tumur necrosis factor alpha (TNF) follows the same time sequence and that it is produced by monocytes/macrophages. The number of capillaries in infiltrates at 3 and 7 days as revealed by the lectin Dolichus Biflorus Agglutinin was high and declined at 4 weeks.In situ hybridisation using a rat cDNA probe for fibronectin showed the increased production of fibronectin mRNA in fibroblasts. To describe the expression of fibronectin and the collagens I, III, VI immunohistochemistry was used. A comparison showed that fibroblasts produced fibronectin mRNA starting at day 3, but the protein was only maximally expressed at day 7 and 4 weeks. Collagen I, III, VI expression was highest at 1–4 weeks. Conclusion: monocytes and macrophages produce the growth factors aFGF and TNF which seem to be important for angiogenesis in the ischemic myocardium. Fibroblasts, while they produce fibronectin and collagen, exert their major function in repair and scar formation, but may take also part in angiogenesis.     

Tumor necrosis factor-α in macrophages of heart,liver, kidney,and in the pituitary gland

The relationship between myonuclear number, cellular size, succinate dehydrogenase activity, and myosin type was examined in single fiber segments (n=54; 9±3 mm long) mechanically dissected from soleus and plantaris muscles of adult rats. One end of each fiber segment was stained for DNA before quantitative photometric analysis of succinate dehydrogenase activity; the other end was double immunolabelled with fast and slow myosin heavy chain monoclonal antibodies. Mean±S.D. cytoplasmic volume/myonucleus ratio was higher in fast and slow plantaris fibers (112±69 vs. 34±21x10³ m³) than fast and slow soleus fibers (40±20 vs. 30±14x10³ m³), respectively. Slow fibers always had small volumes/myonucleus, regardless of fiber diameter, succinate dehydrogenase activity, or muscle of origin. In contrast, smaller diameter (<70 m) fast soleus and plantaris fibers with high succinate dehydrogenase activity appeared to have low volumes/myonucleus while larger diameter (>70 m) fast fibers with low succinate dehydrogenase activity always had large volume/myonucleus. Slow soleus fibers had significantly greater numbers of myonuclei/mm than did either fast soleus or fast plantaris fibers (116±51 vs. 55±22 and 44±23), respectively. These data suggest that the myonuclear domain is more limited in slow than fast fibers and in the fibers with a high, compared to a low, oxidative metabolic capability.     

Referate

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Allgemeines,Genetik, Cytologie,Physiologie

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The complex for replication initiation of<Emphasis Type="Italic">Escherichia coli</Emphasis>

We probed the complex betweenoriC and DnaA protein using two types of mutants inoriC. Base changes in the DnaA binding sites, DnaA boxes, had little effect on origin function. Mutations which change the distance between DnaA boxes R3 and R4, on the other hand, inactivatedoriC unless the mutation deleted or inserted one complete helical turn. Origins with other 10 base pair insertions in the interval between DnaA boxes R2 and R3 were functional, but not insertions in the R1–R2 interval. FIS protein binds to a bipartite site inoriC between DnaA boxes R2 and R3. A model for theoriC/DnaA complex based on these results suggests an array of DnaA monomers with a 34 Å spacing upon whichoriC is arranged.     

Salt dependent changes in structure and dynamics of circular single stranded DNA of filamentous phages of Escherichia coli

We have analyzed the static and dynamic behaviour of the circular single stranded DNA of the filamentous Escherichia coli phages F1 and M13mp8 in solution as a function of salt concentration using static and dynamic light scattering and sedimentation analysis in the analytical ultracentrifuge. We show by static light scattering that native and denatured single stranded DNA behave like a randomly coiled macromolecule at all salt concentrations used. The size of the native single stranded DNA is governed by the formation of secondary structures. While the radius of gyration decreases with increasing salt concentration the translational diffusion of the center-of-mass of native single stranded DNA and the sedimentation coefficient increase with increasing salt concentration in a biphasic manner. Below 100 mM monovalent cation concentration there is a strong dependence of the hydrodynamic parameters upon salt which is reduced approx. 3-fold at higher salt concentrations. We attribute the compaction of single stranded DNA by salt to electrostatic shielding and, in case of native single stranded DNA, secondary structure formation. Internal motions of the native single stranded DNA are observable at all salt concentrations and can be interpreted with a model of segmental diffusion of the elements of the polymer chain. The observed segmental diffusion coefficient of the native single stranded polynucleotide increases with increasing salt under the conditions investigated.