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The role of contact with nickel-containing coins has been controversial. The aim of our study was to compare the release of nickel from Euro (1 and 2) coins and from Polish coins (2 PLN and 5 PLN) at 4ºC and 32ºC in an immersion test using artificial sweat according to the EU reference method. Nickel extract was analyzed at 8 time points starting from 1 h up to 168 h. After 7 days of test duration at 32ºC, nickel ion concentration was 96.27±4.01 μg/cm2, 79.31±1.95 μg/cm2, 38.34±1.19 μg/cm2, and 32.17±2.36 μg/cm2 for 2 Euro, 1 Euro, 5 PLN, and 2 PLN, respectively. The amount of nickel ion released at 4ºC was reduced by about 70% and 40% for Euro and Polish coins, respectively. These values exceed the limit acceptable for prolonged contact with human skin as defined by the EU Nickel Directive, which indicates that nickel may be capable of eliciting allergic reactions in subjects handling nickel-containing coins daily.
Bacteria of Desulfovibrio desulfuricans species are Gram-negative, anaerobic rods selectively reducing sulphates and colonizing oxygen-free ecosystems. They are ubiquitous in the natural environment and have been also found to reside in the human digestive tract. They are suggested to be involved in the pathogenesis of ulcerative colitis and Crohn's disease. The D. desulfuricans wild strains were isolated from feces and bioptate of patients suffering from various digestive tract disorders. LPSs were isolated from the wild enteric strains and soil type strain La 2226 of D. desulfuricans and analyzed in terms of their 2-keto-3-deoxyoctulosonic acid (Kdo) component content. The obtained spectrophotometric data indicate that Kdo content is characteristic of each of the investigated strains and it ranges from 0.48% to 2.86% (w/w) of the total LPS mass. Statistically significant interstrain differences of Kdo quantity seem to suggest the differences in the O-antigen content. Comparative analysis of Kdo content in LPSs of D. desulfuricans strains in relation to that of the reference endotoxin from Salmonella spp. allows us to suggest that D. desulfuricans bacteria possess O-antigen polysaccharides composed of diverse number of carbohydrate units.
The aim of this study was to analyze the molecular mechanism of inositol hexaphosphate (InsP6) action through which it may inhibit proliferation of colon cancer cells and cell cycle progression. A kinetic study of p53 and p21WAF1 mRNA increase was performed on human colon cancer HT-29 cells after treatment with 1, 5 and 10 mM InsP6 for 6, 12, 24 and 48 h. Real-time-QPCR based on TaqMan methodology was applied to analyze quantitatively the transcript levels of these genes. The transcription of β-actin and GAPDH genes was assessed in parallel to select the control gene with least variability. The 2-ΔΔCt method was used to analyze the relative changes in gene transcription. InsP6 stimulated p53 and p21WAF1 expression at the mRNA level, with the highest increase in p21WAF1 mRNA occurring at 24 h, i.e., following the highest increase in p53 mRNA observed at 12 h. Based on these studies it may be concluded that the ability of InsP6 to arrest the cell cycle may be mediated by the transcriptional up-regulation of the p53-responsive p21WAF1 gene.
Gut-derived adenocarcinoma Caco-2 cells were treated with sodium butyrate (NaB) at physiologically relevant concentrations. We characterized its effects on prolifera­tion, differentiation, apoptosis, adhesion to the solid support and interleukin-8 secre­tion. Differentiation was determined by brush border alkaline phosphatase activity. Apoptosis was assessed by acridine orange and Hoechst stains. Differentiation and apoptosis were analyzed in both adherent and floating cell populations. The trans­formed Caco-2 cells did not retain their malignant phenotype in the presence of NaB. They appeared to undergo a change in the phenotype induced by NaB, as indicated by reduced proliferation, enhanced differentiation, stimulation of apoptosis leading to decreased viability of cells, and stimulation of interleukin-8 secretion. Considering all the above facts and data, we postulate that Caco-2 cells cultured in NaB supplemented medium could regain the phenotypic characteristics of the phenotype of the parent cell from which originated the Caco-2 line.
Inflammatory cytokines, including TNF-α, are produced by mononuclear leukocytes in response to numerous agents, such as microorganisms and microbial products, e.g., lipopolysaccharides (LPSs). We studied the modulation of LPS-induced release of TNF-α from human mononuclear cells by inositol hexaphosphate (IP6). This naturally occurring phytochemical, abundantly present in a regular diet, possesses several pharmacological activities beneficial for human health involving anticancer function and the ability to enhance the immune system. The present study on the effect of IP6 on the challenge of host defense system in cases of endotoxemia adds more to physiological importance of IP6 in terms of its immunomodulatory activity. Incubation of cells with IP6 alone (up to 250 µM) had no effect upon the basal secretion of TNF-α, whereas at higher doses it acted as an agonist by up-regulating the cytokine release. Incubation of cells with IP6 prior to LPS challenge resulted in differential effects which were dependent on triggering LPS. The response of cells to LPS from Desulfovibrio desulfuricans and Escherichia coli was diminished by IP6. Cell priming by IP6, resulting in up-regulation of TNF-α release was observed with Salmonella minnesota LPS stimulation. These results indicate that IP6 may exert immunoregulatory effects on mononuclear cell function and control their level of activation states.
Mononuclear cells play an important role in the regulation of microbe-induced inflammation, in part through their ability to secrete cytokines in response to microorganisms and their products. To evaluate the effects of Desulfovibrio desulfuricans-derived endotoxins on TNF-a induction, lipopolysaccharides (LPSs) isolated from soil and intestinal strain were used to stimulate peripheral blood mononuclear cells. The effect of these LPSs was assessed in comparison to that of LPSs from Escherichia coli, Salmonella minnesota and of lipid A from Salmonella minnesota. Level of TNF-a was measured by enzyme-linked immunosor­bent assay. D. desulfuricans LPSs at the highest dose (1000 ng/ml) displayed greater biological potency in inducing TNF-a secretion than other endotoxins used which indicates that these LPSs may act as a critical regulatory factor in bacteremia caused by these microorganisms.
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