Microbial populations associated with treatment of an industrial dye effluent in an anaerobic baffled reactor.
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Fluorescent in situ hybridization (FISH) using 16S and 23S rRNA-targeted probes together with construction of an archaeal 16S ribosomal DNA (rDNA) clone library was used to characterize the microbial populations of an anaerobic baffled reactor successfully treating industrial dye waste. Wastewater produced during the manufacture of food dyes containing several different azo and other dye compounds was decolorized and degraded under sulfidogenic and methanogenic conditions. Use of molecular methods to describe microbial populations showed that a diverse group of Bacteria and Archaea was involved in this treatment process. FISH enumeration showed that members of the gamma subclass of the class Proteobacteria and bacteria in the Cytophaga-Flexibacter-Bacteroides phylum, together with sulfate-reducing bacteria, were prominent members of a mixed bacterial population. A combination of FISH probing and analysis of 98 archaeal 16S rDNA clone inserts revealed that together with the bacterial population, a methanogenic population dominated by Methanosaeta species and containing species of Methanobacterium and Methanospirillum and a relatively unstudied methanogen, Methanomethylovorans hollandica, contributed to successful anaerobic treatment of the industrial waste. We suggest that sulfate reducers, or more accurately sulfidogenic bacteria, together with M. hollandica contribute considerably to the treatment process through metabolism of dye-associated sulfonate groups and subsequent conversion of sulfur compounds to carbon dioxide and methane. (+info)
Efficacy of dye-stained enteral formula in detecting pulmonary aspiration.
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STUDY OBJECTIVE: To determine the extent to which a mixture of human gastric juice and enteral formula stained with two concentrations of FD&C Blue No. 1 food dye (0.8 and 1.5 mL/L) is visible in suctioned tracheobronchial secretions following three forced small-volume pulmonary aspirations over a 6-h period in an animal model. DESIGN: Experimental 2 x 3 repeated measures. SETTING: Animal laboratory and an acute care hospital. PARTICIPANTS: Ninety New Zealand white rabbits weighing approximately 3 kg each, and 90 acutely ill adults who furnished gastric juice. INTERVENTIONS: A mixture of human gastric juice and enteral formula stained with 0.8 or 1.5 mL of dye per liter was instilled intratracheally over a 30-min period into anesthetized intubated animals at baseline, 2 h, and 4 h. A total of 0.4 mL/kg of the mixture was instilled at each session. Ninety minutes after each instillation, suctioned secretions were examined for visible dye and blood. MEASUREMENTS AND RESULTS: Dye was visible in 46.3% of the secretions (125 of 270). The concentration of dye had no significant effect on dye visibility. Blood that was present in 114 of 270 of the secretions (42.2%) interfered with dye visibility in all but two secretions. For reasons unknown, even in the absence of blood, dye visibility decreased from 90.2% (55 of 61 secretions) after the first aspiration event to only 61% (25 of 41 secretions) after the third aspiration event. CONCLUSIONS: Findings from this animal model study do not support the use of the dye method to detect repeated small-volume aspirations. For clinicians who choose to use the dye method in selected situations, it appears that a dye concentration of 0.8 mL/L may be as effective in detecting aspiration as a 1.5 mL/L concentration. (+info)
Detection of diacetyl (caramel odor) in presumptive identification of the "Streptococcus milleri" group.
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The caramel odor associated with the "Streptococcus milleri" group was shown to be attributable to the formation of the metabolite diacetyl. Levels of diacetyl in the 22- to 200-mg/liter range were produced by 68 strains of the "S. milleri" group; apart from one strain of Streptococcus mutans, all 92 other strains of streptococci belonging to 12 species produced < 13 mg of diacetyl per liter. Quantitation of diacetyl levels from cultures of streptococci is suggested as a rapid presumptive test for the "S. milleri" group. (+info)
Four-week oral toxicity study of 1-carboxy-5,7-dibromo-6-hydroxy-2,3,4-trichloroxanthone (HXCA), an impurity of Phloxine B, in F344 rats.
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This study was designed to evaluate and characterize any subacute toxicity of 1-carboxy-5,7-dibromo-6-hydroxy-2,3,4-trichloroxanthone (HXCA), an impurity of Phloxine B (Food Red No. 104 in Japan, D&C Red No. 28 in the USA), when administered to both sexes of F344 rats at dietary levels of 0 (control), 0.005, 0.05 and 0.5%. During the study, the treatment had no effects on clinical signs, survival, urinalysis or ophthalmology. Hematology, blood biochemistry, gross pathology, organ weights, organ to body weight ratios and histopathology exhibited no differences of toxicological significance between control and treated rats. Reactions to treatment may be summarized as follows: there was a tendency for increased food and water consumption and decreased food efficiency in both sexes of the 0.5% group. Thus, these results indicated the no-observed-adverse-effect level (NOAEL) of HXCA to be 0.05% (39.3 mg/kg/day for males, and 41.0 mg/kg/day for females). (+info)
The evaluation of the genotoxicity of two commonly used food colors: Quinoline Yellow (E 104) and Brilliant Black BN (E 151).
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Additives, especially colors, are in widespread use in the food industry. With the exception of the quinolines, food colors are relatively weak mutagens and are certified as safe additives despite reports that some people have allergic reactions to them. The number of food additives is still on the increase, and research on their potential mutagenic/carcinogenic activity in vivo is very expensive. Using two different cellular model systems, human lymphocytes in vitro and Vicia faba root tip meristems of in vivo, we evaluated the potential cytological and genotoxic effects of two dyes: Quinoline Yellow (E 104) and Brilliant Black BN (E 151). Two relatively new, very sensitive and rapid tests - the micronucleus and Comet assays - were used in this study. The data provided in this paper showed the genotoxic effects of the two analyzed food colors, and confirmed the diagnostic value of the MN and Comet assays for screening potentially genotoxic substances. (+info)
Effect of mixing method on the mixing degree during the preparation of triturations.
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By using lactose colored with erythrocin, we investigated the effects of mixing methods on mixing degree during the preparation of trituration with a mortar and pestle. The extent of powder dilution was set to 4 to 64 fold in the experiments. We compared the results obtained by using two methods: (1) one-step mixing of powders after addition of diluents and (2) gradual mixing of powders after addition of diluents. As diluents, we used crystallized lactose and powdered lactose for the preparation of trituration. In the preparation of 64-fold trituration, an excellent degree of mixing was obtained, with CV values of less than 6.08%, for both preparation methods and for the two kinds of diluents. The mixing of two kinds of powders whose distributions of particle sizes were similar resulted in much better degree of mixing, with CV values of less than 3.0%. However, the concentration of principal agents in 64-fold trituration was reduced by 20% due to the adsorption of dye to the apparatus. Under conditions in which a much higher dilution rate and/or much better degree of dilution was required, it must be necessary to dilute powders with considering their physicality and to determine the concentrations of principal agents after the mixing. (+info)
Effect of particle size on mixing degree in dispensation.
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By using lactose colored with erythrocin, we examined the effect of particle size on mixing degree during the preparation of triturations with a mortar and pestle. We used powders with different distributions of particle sizes, i.e., powder that passed through 32-mesh but was trapped on a 42-mesh sieve (32/42-mesh powder), powder that passed through a 42-mesh sieve but was trapped on a 60-mesh sieve (42/60-mesh powder), powder that passed through a 60-mesh sieve but was trapped on a 100-mesh sieve (60/100-mesh powder), and powder that passes through a 100-mesh sieve (> 100-mesh powder). The mixing degree of colored powder and non-colored powder whose distribution of particle sizes was the same as that of the colored powder was excellent. The coefficient of variation (CV) value of the mixing degree was 6.08% after 40 rotations when colored powder was mixed with non-colored powder that both passed through a 100-mesh sieve. The CV value of the mixing degree was low in the case of mixing of colored and non-colored powders with different particle size distributions. After mixing, about 50% of 42/60-mesh powder had become smaller particles, whereas the distribution of particle sizes was not influenced by the mixing of 60/100-mesh powder. It was suggested that the mixing degree is affected by distribution of particle sizes. It may be important to determine the mixing degrees for drugs with narrow therapeutic ranges. (+info)
The effects of a double blind, placebo controlled, artificial food colourings and benzoate preservative challenge on hyperactivity in a general population sample of preschool children.
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AIMS: To determine whether artificial food colourings and a preservative in the diet of 3 year old children in the general population influence hyperactive behaviour. METHODS: A sample of 1873 children were screened in their fourth year for the presence of hyperactivity at baseline (HA), of whom 1246 had skin prick tests to identify atopy (AT). Children were selected to form the following groups: HA/AT, not-HA/AT, HA/not-AT, and not-HA/not-AT (n = 277). After baseline assessment, children were subjected to a diet eliminating artificial colourings and benzoate preservatives for one week; in the subsequent three week within subject double blind crossover study they received, in random order, periods of dietary challenge with a drink containing artificial colourings (20 mg daily) and sodium benzoate (45 mg daily) (active period), or a placebo mixture, supplementary to their diet. Behaviour was assessed by a tester blind to dietary status and by parents' ratings. RESULTS: There were significant reductions in hyperactive behaviour during the withdrawal phase. Furthermore, there were significantly greater increases in hyperactive behaviour during the active than the placebo period based on parental reports. These effects were not influenced by the presence or absence of hyperactivity, nor by the presence or absence of atopy. There were no significant differences detected based on objective testing in the clinic. CONCLUSIONS: There is a general adverse effect of artificial food colouring and benzoate preservatives on the behaviour of 3 year old children which is detectable by parents but not by a simple clinic assessment. Subgroups are not made more vulnerable to this effect by their prior levels of hyperactivity or by atopy. (+info)