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  • 1
    ISSN: 1398-9995
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background: ICAM-3 has been recently identified as the third leukocyte-function associated-1 (LFA-1) ligand. ICAM-3 is expressed in eosinophils, but its regulation has not been studied. The objective of this study was to investigate the differential expression of ICAM-3 and other adhesion molecules (AM) on the surface of eosinophils. We also evaluated the effects of dexamethasone on AM expression. Methods: Normodense eosinophils were isolated from peripheral blood and incubated with calcium ionophore A23187 (calcimycin) with and without dexamethasone. Expression of AM was assessed by flow cytometry and expressed as fluorescence mean intensity (FMI). Results: Peripheral blood eosinophils constitutively expressed low levels of ICAM-1 and ICAM-2 (〈10 FMI), moderate levels (10–50 FMI) of CD29 and L-selectin, and high levels (〉50 FMI) of ICAM-3, LFA-1, and Mac-1. Calcium ionophore (1 μM) significantly increased Mac-1 and ICAM-1 expression at 6 and 24 h. L-selectin expression decreased at 6 and 24 h, but ICAM-2, ICAM-3, LFA-1, and CD29 expression did not show any significant change after calcium ionophore stimulation. Dexamethasone decreased ICAM-3 and increased L-selectin basal expression, and it caused a dose-related inhibition of calcium ionophore-induced ICAM-1 expression. Conclusions: These findings suggest that some AM, such as ICAM-1, Mac-1, and L-selectin, may be involved in adhesion during eosinophil activation and that glucocorticoids may prevent airway inflammation by regulating the expression of AM in eosinophils. The role of ICAM-3, a leukocyte AM highly expressed in resting eosinophils, remains to be clarified.
    Type of Medium: Electronic Resource
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  • 2
    Abstract: Graves' disease (GD) is the paradigm of an anti-receptor autoimmune disease, with agonistic auto-antibodies against the thyrotropin receptor (TSHR-thyroid-stimulating hormone receptor) being the underlying pathogenic effector mechanism. The TSHR belongs to the category of tissue-restricted antigens, which are promiscuously expressed in the thymus and thereby induce central T cell tolerance. In order to understand the association between TSHR gene polymorphisms and GD, we tested the hypothesis that TSHR gene variants affect susceptibility to GD by influencing levels of TSHR transcription in the thymus. We show that thymic glands from non-autoimmune donors homozygous for the rs179247 SNP predisposing allele of TSHR had significantly fewer TSHR mRNA transcripts than carriers of the protective allele. In addition, in heterozygous individuals, the TSHR predisposing allele was expressed at a lower level than the protective one as demonstrated by allele-specific transcript quantification. This unbalanced allelic expression was detectable in both thymic epithelial cells and thymocytes. Since the level of self-antigen expression is known to influence the threshold of central tolerance, these results are compatible with the notion that defective central tolerance contributes to the pathogenesis of GD, a scenario already implicated in type 1 diabetes mellitus, myasthenia gravis and autoimmune myocarditis.
    Type of Publication: Journal article published
    PubMed ID: 21642385
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  • 3
    ISSN: 1432-072X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Das Enzym Acetoin-Dehydrogenase wird von zahlreichen Kohlenstoffquellen katabolisch reprimiert. Die folgenden Bufunde weisen darauf hin, daß die Repression dieses Enzyms und die Inhibition der Sporulation durch den gleichen Mechanismus erfolgen. 1. Mutanten, isoliert nach ihrer Fähigkeit, Acetoin Dehydrogense trotz Anwesenheit von Glucose zu bilden, können auch in Glucose Medium in einer höheren Rate als der Wildtyp sporulieren. 2. Die Fähigkeit einer Kohlenstoffquelle, die Induktion der Acetoin-Dehydrogenase zu hemmen, ist ihrer sporulationsinhibierenden Wirkung proportional. 3. Phosphatlimitierung im Medium, was bekanntlich Sporulation fördert, hat eine der katabolischen Repression entgegengesetzte Wirkung.
    Notes: Abstract Acetoin dehydrogenase can be catabolite repressed by numerous sources of carbon. The following results point out that the catabolite repression of this enzyme and the inhibition of sporulation are mediated by the same mechanism: 1. Mutants, able to synthesize acetoin dehydrogenase in the presence of glucose, sporulate in glucose medium at a higher rate than the standard strain. 2. The catabolite repressing effect of a compound and its ability to inhibit sporulation are in a direct relation to each other. 3. The limitation of inorganic phosphate in the growth medium, which is known to favour sporulation, counteracts the catabolite repressing effect of glucose.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-072X
    Keywords: Alternate oxidase ; Cytochrome c 2 ; Cytochrome oxidase ; Respiratory chain ; Terminal oxidases ; Rhodospirillum rubrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Rhodospirillum rubrum CAF10, a spontaneous cytochrome oxidase defective mutant, was isolated from strain S1 and used to analyze the aerobic respiratory system of this bacterium. In spite of its lack of cytochrome oxidase activity, strain CAF10 grew aerobically in the dark although at a decreased rate and with a reduced final yield. Furthermore, aerobically grown mutant cells took up O2 at high rates and membranes isolated from those cells exhibited levels of NADH and succinate oxidase activities which were similar to those of wild type membranes. It was observed also that whereas in both strains O2 uptake (intact cells) and NADH and succinate oxidase activities (isolated membranes) were not affected by 0.2 mM KCN, the cytochrome oxidase activity of the wild type strain was inhibited about 90% by 0.2 mM KCN. These data indicate the simultaneous presence of two terminal oxidases in the respiratory system of R. rubrum, a cytochrome oxidase and an alternate oxidase, and suggest that the rate of respiratory electron transfer is not limited at the level of the terminal oxidases. It was also found that the aerobic oxidation of cellular cytochrome c 2 required the presence of a functional cytochrome oxidase activity. Therefore it seems that this electron carrier, which only had been shown to participate in photosynthetic electron transfer, is also a constituent of the respiratory cytochrome oxidase pathway.
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  • 5
    ISSN: 1432-072X
    Keywords: Key wordsThermococcus peptonophilus ; Thermococcales ; Extreme thermophiles ; Archaea ; Deep-sea hydrothermal vents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two extremely thermophilic archaebacteria, strains OG-1 and SM-2, were isolated from newly discovered deep-sea hydrothermal vent areas in the western Pacific ocean. These strains were cocci, obligately anaerobic Archaea about 0.7–2 μm in diameter. Optimum growth conditions for OG-1 and SM-2 were at 85–90°C (range 60–100°C), pH 6 (range pH 4–8), a NaCl concentration of 3% (range 1–5%), and a nutrient concentration (tryptone plus yeast extract) of 0.2% (range 0.005–5%). Elemental sulfur stimulated the growth rate fourfold. Ammonium slightly stimulated growth. Both tryptone and yeast extract allowed growth as sole carbon sources; these isolates were not able to utilize or grow exclusively on sucrose, glucose, maltose, succinate, pyruvate, propionate, acetate, or free amino acids. OG-1 showed the fastest growth rate within the genus Thermococcus. Growth was inhibited by rifampicin. The DNA G+C content was 52 mol%. Sequencing of their 16S rDNA gene fragment indicated that these isolates belonged to the genus Thermococcus. OG-1 and SM-2 were different than the described Thermococcus species. We propose that OG-1 belongs to a new species: Thermococcus peptonophilus.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0738
    Keywords: Cis-platinum ; Walker 256 carcinoma ; Nephrotoxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The elevations of blood urea nitrogen and serum creatinine caused by cis-platinum in rats can be prevented by a combination of procedures centered around the administration of sodium N-methyl-N-dithiocarboxyglucamine (NaG), before and very soon after the cis-platinum is administered in hypertonic (4.5%) saline. Elevations inblood urea nitrogen and serum creatinine levels subsequent to such treatment are largely eliminated. These same procedures appear to have no effect on the anti-tumor action of the cis-platinum, as measured by tumor size and mass and by survival times, in female Sprague-Dawley rats inoculated with the Walker 256 carcinoma. The degree of myelosuppression, as measured by the white blood cell count is also slightly reduced. White blood cell counts returned to normal values more rapidly in animals treated with NaG than in those treated with cis-platinum alone. An examination of the dose-response curve for the suppression of cis-platinum nephrotoxicity by NaG shows that this can be achieved with mole ratios of NaG: cis-platinum as low as 1∶1 given after appropriate pretreatment. A preliminary structure-activity study on the suppression of cis-platinum induced elevations in blood urea nitrogen and serum creatinine by four closely related dithiocarbamates shows that this can also be achieved effectively by several dithiocarbamates in which the nitrogen atom bears polar substituents.
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  • 7
    ISSN: 1432-0738
    Keywords: Gallium nitrate ; Deferoxamine mesylate ; Citric acid ; Succinic acid ; Malic acid ; Oxalic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Twelve chelating agents were administered to mice by IP injection to compare their relative effectiveness in preventing death after a single IP injection of gallium nitrate. Na2Ca-ethylenediaminetetraacetate (EDTA), Na3Ca-diethylenetriaminepentaacetate (DTPA), dimercaptosuccinic acid (DMSA), 4,5-dihydroxy-1,3-benzenedisulfonic acid (Tiron), sodium diethyldithiocarbamate (DDC), L-cysteine and sodium salicylate were not effective for acute gallium nitrate intoxication. The therapeutic indices of the effective chelators were: 25.4 (deferoxamine mesylate), 35.7 (citric acid), 42.3 (succinic acid), 52.2 (malic acid) and 111.1 (oxalic acid).
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 61 (1988), S. 321-323 
    ISSN: 1432-0738
    Keywords: Zinc ; Mice ; Intraperitoneal administration ; Zinc antidotes ; EDTA ; DTPA ; CDTA ; d-penicilamine ; DMPS ; DMSA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Sixteen chelating agents were examined to determine their relative efficacy as antidotes in acute zinc acetate intoxication in mice after i.p. administration. For a i. p. dose of 0.49 mmol/kg (LD50) of zinc acetate, the i. p. administration of chelating agents at a 2∶1 and 5∶1 mole ratio resulted in a significant antidotal action for EDTA, DTPA, CDTA, d-penicillamine (d-PA), DMPS and DMSA. EGTA, l-cysteine, triethylentetraamine (TTHA), N-acetylcysteine (NAC), 4,5-dihydroxi-1,3-benzenedisulfonic acid (Tiron), sodium salicylate, glutathione, sodium diethyldithiocarbamate (DDC), 6-mercaptopurine and N-acetyl-d, l-penicillamine (NAPA) were not effective for acute zinc acetate poisoning. The therapeutic indices and therapeutic effectiveness of the most effective chelators were, respectively: EDTA (5.0, 7.0), DTPA (7.3, 13.7), CDTA (8.6, 6.3), d-PA (4.6, 1.9), DMPS (1.3, 1.0), DMSA (3.2, 5.4). DTPA, CDTA, and EDTA appear to be the most effective agents of those tested in offsetting acute zinc intoxication in mice.
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  • 9
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The microwave-assisted extraction (MAE), accelerated solvent extraction (ASE) and Soxhlet extraction of two isomers of hexachlorocyclohexane, α-HCH and γ-HCH, from a polluted landfill soil have been optimized following different experimental designs. In the case of microwave-assisted extraction, the following variables were considered: pressure, extraction time, microwave power, percentage of acetone in n-hexane mixture and solvent volume. When ASE extraction was studied the variables were pressure, temperature and extraction time. Finally, the percentage of acetone in n-hexane mixture and the extraction time were the only variables studied for Soxhlet extraction. The concentrations obtained by the three extraction techniques were, within their experimental uncertainties, in good agreement. This fact assures the possibility of using both ASE and MAE techniques in the routine determination of lindane in polluted soils and sediments.
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  • 10
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The zinc concentration in the brains of two species of lizard was determined by atomic-absorption spectrophotometry. The zinc concentration was found to be highest in the telencephalon of Lacerta galloti (21.1 μg/g fresh weight) and Podarcis hispanica (16.77±0.8 μg/g) while the mesencephalon and brain stem exhibited lower zinc concentrations, i.e., 7.0 μg/g in Lacerta galloti and 6.08±0.4 μg/g in Podarcis hispanica. This high telencephalic concentration of zinc is paralleled by intense and well-defined Timm reactivity used for demonstrating the presence of zinc-containing boutons at the light-microscope level. Volumetricdensitometric studies of these Timm-reactive zones were performed using serial transverse sections of the same lizard brains.
    Type of Medium: Electronic Resource
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