Small-bowel capsule endoscopy in patients with gastrointestinal food allergy.

BACKGROUND: Food allergy may present with a plethora of gastrointestinal and extraintestinal symptoms such as abdominal pain, diarrhea, cardiocirculatory symptoms, cutaneous reactions, or rhinitis. Macropathological lesions like lymphofollicular hyperplasia and erosive or ulcerative lesions have seldom been described in gastroscopy and colonoscopy previously. METHODS: Fifteen patients presenting with unspecific abdominal symptoms in which food allergy was detected in due course were included. During the examination process, those patients showed various indications for small-bowel capsule endoscopy, such as weight loss and anemia. RESULTS: Fourteen (93.3%) of the 15 small-bowel capsule endoscopies could be assessed, showing nonerosive lesions such as erythema, swelling, and lymphoid hyperplasia in 8 patients (57.1%) and erosive lesions such as aphthoid lesions, erosions, and petechiae in 4 patients (28.6%) with food allergy. CONCLUSION: In 15 patients with confirmed food allergy and after exclusion of other diseases, 12 (85.7%) showed various unspecific nonerosive or erosive mucosal lesions within the small bowel, resulting, however, partially in grave consequences such as anemia. Lymphoid hyperplasia was the most prominent finding in 7 patients (50%), albeit infectious disease had been excluded. Anemia improved within 1 year after adequate antiallergic treatment.

Substituent effects on the oxidation of substituted biphenyl congeners by type II methanotroph strain CSC1.

The oxidation potential of type II groundwater methanotroph, strain CSC1, expressing soluble methane monooxygenase, was measured in the presence of 10 ortho-substituted biphenyls with varying electronics, sterics, and hydrophobicity character for comparison with type II Methylosinus trichosporium OB3b. Strain CSC1 showed faster rates with all compounds tested, with the exception of 2-nitrobiphenyl, 2-hydroxybiphenyl, and 2-aminobiphenyl. Products of oxidation observed upon incubation of strain CSC1 with biphenyl and 2-hydroxybiphenyl were hydroxylated biphenyls that revealed less preference for the para position and different dihydroxylation positions, respectively, in comparison to those observed with M. trichosporium OB3b. Only the intramolecular hydrogen migration, or NIH-shift, product was observed in the case of 2-chlorobiphenyl, whereas M. trichosporium OB3b yielded a variety of chlorohydroxybiphenyls. Quantitative structure-biodegradation relationships constructed with the maximum observed oxygen uptake rates as a dependent variable and a variety of descriptors showed an influence of substituent electronic character on the oxidation activity of strain CSC1. However, compound hydrophobicity and not compound size, as was observed with M. trichosporium OB3b, was shown to influence rates to a greater extent. This suggests that transport of the compound through the cell membrane and to the sMMO active site is rate-determining for strain CSC1.

Characterization of methanogenic and methanotrophic assemblages in landfill samples.

A greater understanding of the tightly linked trophic groups of anaerobic and aerobic bacteria residing in municipal solid waste landfills will increase our ability to control methane emissions and pollutant fate in these environments. To this end, we characterized the composition of methanogenic and methanotrophic bacteria in samples taken from two regions of a municipal solid waste landfill that varied in age. A method combining polymerase chain reaction amplification, restriction fragment length polymorphism analysis and phylogenetic analysis was used for this purpose. 16S rDNA sequence analysis revealed a rich assemblage of methanogens in both samples, including acetoclasts, H2/CO2-users and formate-users in the newer samples and H2/CO2-users and formate-users in the older samples, with closely related genera including Methanoculleus, Methanofollis, Methanosaeta and Methanosarcina. Fewer phylotypes of type 1 methanotrophs were observed relative to type 2 methanotrophs. Most type 1 sequences clustered within a clade related to Methylobacter, whereas type 2 sequences were broadly distributed among clades associated with Methylocystis and Methylosinus species. This genetic characterization tool promises rapid screening of landfill samples for genotypes and, therefore, degradation potentials.

Transformation of ortho-substituted biphenyls by Methylosinus trichosporium OB3b: substituent effects on oxidation kinetics and product formation.

The ability of Methylosinus trichosporium OB3b, expressing soluble methane monooxygenase, to oxidize a range of ortho-substituted biphenyls was examined to better understand how substituents affect both the rate and products of oxidation in comparison to biphenyl. Inhibition of oxidation was observed over the tested substrate range for both biphenyl and ortho-halogenated biphenyls (2-chloro-, 2-bromo-, and 2-iodobiphenyl). No inhibition was observed during the oxidation of 2-hydroxybiphenyl and 2-methylbiphenyl. Analysis of the products of oxidation showed that, depending on the substituent, ring hydroxylation, substituent oxidation, and elimination pathways could occur. The type and abundance of products formed along with the relatively high kinetic isotope effect observed for deuterated vs. nondeuterated biphenyl (k(h)/k(d) = 3.4+/-0.02) are consistent with mechanisms that include both hydrogen abstraction and NIH-shift pathways. Knowledge of these substituent-dependent reaction rates and mechanisms enhances our understanding of the methanotrophic aryl transformation potential and allows for better prediction of the formation of oxidized intermediates by methanotrophic bacteria.