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  • 1
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In this study, we wished to clarify the distribution and co-localization of nitric oxide synthase and NADPH-diaphorase (NADPH-d) in nerve cells, nerve fibres and parenchymal cells in exocrine and endocrine pancreas, and to assess the influence of fixation on the staining pattern obtained. For this purpose, we applied nitric oxide synthase immunocytochemistry and NADPH-d histochemistry to rat and human pancreas under different fixation conditions. Antibodies to neuronal and endothelial nitric oxide synthase were similarly applied. We found complete co-localization of neuronal nitric oxide synthase and NADPH-d in ganglion cells, and in nerve fibres around acini, excretory ducts, blood vessels and in islets of Langerhans of rat and human pancreas. Immunoreactivity for endothelial nitric oxide synthase was co-localized with NADPH-d in endothelial cells. However, in NADPH-d reactive islet and ductal epithelial cells we could detect neither brain nor endothelial nitric oxide synthase immunoreactivity with any fixation protocol applied. There were marked differences in NADPH-d staining of both neurons and parenchymal cells under different fixation conditions. These results indicate the existence of different types of NADPH-d, which are associated or not associated with nitric oxide synthase(s), and which are differently influenced by various fixation procedures in rat and human pancreas.
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  • 2
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Nitric oxide (NO)-synthase immunoreactivity has been detected for the first time in mast cells of human normal nasal mucosa, with an antibody specific for neuronal NO-synthase. Intense immunoreactivity was revealed in secretion granules of mast cells but was found in mast cell granules free in the extracellular matrix only in some instances; no reactivity was found in the cytoplasm of this or other cell types. These findings suggest that human nasal mast cells contain a particulate isoform of NO-synthase, which shares epitopes with neuronal NO-synthase and is rapidly removed from granules upon exocytosis.
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  • 3
    ISSN: 1434-601X
    Keywords: 14.80.Pb ; 21.40.+d ; 25.10.+s
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Some evidence is presented for a narrow peak at 1969±2 MeV (FWHM=9±2 MeV) in the missing mass spectrum of the3He(p, d) reaction, with 3 standard deviations. The nature of this state, the mass of which is below the NN threshold, is discussed in connection with structures found in other experiments.
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  • 4
    ISSN: 1432-0878
    Keywords: Key words: Urothelium ; Tartrate-resistant acid phosphatase ; Nitric oxide synthase I ; Superoxide dismutase ; Immunocytochemistry ; Free radicals ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Three enzymes, viz., tartrate-resistant acid phosphatase (TRAP), nitric oxide synthase I (NOS-I), and superoxide dismutase (SOD), involved in the production and metabolism of free radicals or radical equivalents, were demonstrated by immunocytochemistry in the urothelium of the ureters of six patients of various ages. Two of these enzymes (TRAP and NOS-I) were colocalized in the most apical and lateral border of the superficial cells of the urothelium. In contrast, SOD showed a patchy or granular distribution within the supranuclear region of these cells. Intra- and subepithelial macrophages exhibited a weak TRAP, but no NOS-I or SOD, immune reaction. On the basis of the immunocytochemical findings, arguments in favor of a cytotoxic function of the superficial cells of the human urothelium are presented.
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  • 5
    ISSN: 1573-4951
    Keywords: host–guest complexes ; molecular necklace ; molecular recognition ; molecular self-assembly ; molecular solvation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper presents a computational study on the formation of a molecular necklace formed by specific threading of cyclodextrins (CDs) on block copolymers. Structural as well as energetic principles for the selective complexation of α- and β-cyclodextrin with poly(ethylene oxide)–poly(propylene oxide) block copolymers (PEO–PPO) are elucidated considering a diblock copolymer of equimolecular composition (PEO)4–(PPO)4 as guest. A non-statistical distribution of CDs, i.e. α-CDs primarily located on the PEO chain and β-CDs on PPO blocks of the polymer, is based on a variety of structural features and energetic preferences considering both potential as well as solvation energies. This selectivity becomes already obvious considering 1:1 complexes between PEO and PPO monomers and the two CDs, but is increasingly evident when calculating higher order ensembles. Besides the host–guest interaction, docking between CDs themselves is an important, also non-statistical, prerequisite for the self-assembly of highly ordered tubes. The formation of intermolecular hydrogen bonds between adjacent CDs in a tubular aggregate gives an important contribution to the overall stability of the molecular necklace. The net effect, based on the preferential interaction between host and guest as well as between the host molecules themselves, results in the formation of a stable, highly ordered macromolecular, multicomponent aggregate.
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  • 6
    ISSN: 1573-1111
    Keywords: β-Cyclodextrin ; triflumizole ; host-guest complex ; inclusion complex ; solvent accessible surface ; solubility enhancement ; hydrophobic effect ; dynamic Monte Carlo molecular docking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Solubility enhancement of the fungicide triflumicole byβ-cyclodextrin is explained using a thermodynamic approach. The influence of organic cosolvents on the overall equilibrium constants of triflumizole complexation withβ-cyclodextrin in aqueous solutions has been investigated. Their variance in mixed solvents is only partly explained by a competitive inclusion of substrate and cosolvent molecules inβ-cyclodextrin. The geometries of host-guest complexes have been estimated by molecular mechanics calculations. Their broad structural variety caused by the flexibility of host and guest molecules and different association possibilities of triflumizole have been analysed by a dynamic Monte Carlo docking method. The hydrophobic effect has been simulated by cominimization of the hydrophobic contributions to the solvation energy, calculated from the solvent accessible surface area of the complex and the conformational (potential) energy.
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  • 7
    ISSN: 1573-1111
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract We compare spectroscopic properties of higher order complexes of organic guests (e.g. naphthalene, phenols, indole, C60 fullerene) with cyclodextrins (CDx) to results of molecular modeling investigations. Naphthalene 1:2 complexes with α-CDx show high spectral resolution and peculiar triplet properties. Molecular simulations and calculation of the experimentally measured induced circular dichroism (ICD) provide detailed structural information.
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  • 8
    ISSN: 1432-0878
    Keywords: Key words: NO/cGMP pathway ; Testis ; Leydig cells ; Immunocytochemistry ; RIA ; Cell culture ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. In this study we sought to determine whether the main components of the nitric oxide (NO) pathway are localized within the Leydig cells of the human testis and whether the soluble guanylyl cyclase (sGC), the enzyme that accounts for NO effects, is functionally active in these cells. Using an amplified immunocytochemical technique, immunoreactivity for nitric oxide synthase (NOS-I), sGC and cyclic guanosine monophosphate (cGMP) was detected within the cytoplasm of human Leydig cells. Distinct differences in staining intensity were found between individual Leydig cells, between cell groups and between Leydig cells of different patients. By means of a specific cGMP-RIA, a concentration-dependent increase in the quantity of cGMP was measured in primary cultures of human Leydig cells following exposure to the NO donor sodium nitroprusside. In addition, NOS-I immunoreactivity was seen in Sertoli cells, whereas cGMP and sGC immunoreactivity was found in Sertoli cells, some apically situated spermatids and residual bodies of seminiferous tubules. Dual-labelling studies and the staining of consecutive sections showed that there are several populations of Leydig cells in the human testis. Most cells were immunoreactive for NOS-I, sGC and cGMP, but smaller numbers of cells were unlabelled by any of the antibodies used, or labelled for NOS-I or cGMP alone, for sGC and cGMP, or for NOS-I and sGC. These results show that the Leydig cells possess both the enzyme by which NO is produced and the active enzyme which mediates the NO effects. There are different Leydig cell populations that probably reflect variations in their functional (steroidogenic) activity.
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  • 9
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusion Our ongoing study shows that HSF cultures can be used as an in vitro model for AA metabolism studies. The incubation medium however has to be standardised in order to obtain comparable results. The addition of albumin to the medium is necessary for dissolution of different agents like ionophore, indomethacin or others and does not change the AA metabolism. Differences between different cell lines of healthy donors are under investigation but seem to be of minor importance when the skin biopsie is taken from the same place, whereas greater differences were observed between HSF cultured from arm or foreskin biopsies. Finally it could be proved that the cyclooxygenase pathway is more important than that of the lipoxygenase and that 11-HETE derives from the cyclooxygenase and not from the lipoxygenase activity. The main lipoxygenase product is 15-HETE.
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  • 10
    ISSN: 1573-2932
    Keywords: bacterial sulfate reduction ; iron reduction ; sediment ; pore-water chemistry ; acidic mining lake ; stable sulfur isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Chemical, microbiological and stable isotope analyses of sediments from an acidic mining lake were used to evaluate whether biogeochemical processes, such as iron and sulfate reduction, are extant, because such processes can potentially generate alkalinity. Sediment cores were sliced in cm intervals to achieve a high resolution for spatial distribution of organic and inorganic components. Iron, sulfur, carbon, nitrogen and phosphorus as well as the most probable number (MPN) of iron reducing bacteria, the amount of lipid phosphate and the stable isotope compositions of various sedimentary sulfur compounds were measured. Accumulation of degradable organic material, reduced mass fractions of iron, enhanced concentrations of lipid phosphate, high concentrations of DOC and ferrous iron in the pore water and a drastic change of sulfur isotope ratios in the upper 3 cm of the sediment all indicated a highly reactive zone of biogeochemical transformations. The data provide clear evidence for iron and sulfate reducing processes in the sediments that result in an increase of pH with depth.
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