Non-invasive detection of Helicobacter pylori in cystic fibrosis--the fecal test vs. the urea breath test.

OBJECTIVES: Only recently it has been proven that cystic fibrosis (CF) patients have the same prevalence of Helicobacter pylori (HP infection) as the general population, as well as the same spectrum of changes caused by this pathogen. The aim of this study was to assess the reliability of the two most popular noninvasive tests--the urea breath test (UBT) and the fecal test (FT) in diagnosing HP infection in CF patients. PATIENTS AND METHODS: The study was conducted on 79 CF patients and 49 healthy subjects (HS). The presence of HP infection was evaluated using the 13C isotope-labeled urea breath test and the fecal test (ELISA). RESULTS: Fifteen (19.0%) CF patients and eight (16.3%) HS were found to be HP positive using the UBT. The HP stool antigen was detected in twelve (15.2%) CF patients and seven (14.3%) HS. Discordant results for the two tests were obtained in 9 out of 18 (50.0%) CF patients and 3 out of 9 (33.3%) HS. Although the differences were not statistically significant, the risk of potentially false negative and false positive results in CF subjects seems to be high. Similarly, no statistical differences in the basic clinical parameters were documented between the CF subgroups with concordant and divergent HP results. CONCLUSIONS: Since there is convincing evidence of divergent UBT and FT results in the CF patients, we suggest that UBT is kept as the standard method for HP detection in this population, at least until obtaining reliable and valid results allows for a change in such an approach.

Percentile distributions of waist circumference for 7-19-year-old Polish children and adolescents.

The aim of the study was to develop waist circumference (WC) percentiles in Polish children and youth and to compare these with the results obtained in other countries. The study comprised a random group of 5663 Polish children aged 7-18 years. Smoothed WC percentile curves were computed using the LMS method. The curves displaying the values of the 50th (WC(50)) and the 90th (WC(90)) percentile were then compared with the results of similar studies carried out in children from the UK, Spain, Germany, Turkey, Cyprus, Canada and the USA. WC increased with age in both boys and girls and in all observed age periods the boys were seen to dominate. For 18-year-old Polish boys and girls the values of WC(90) were 86.5 and 78.2, respectively, and were lower than the current criteria developed by the International Diabetes Federation. Both WC(50) and WC(90) were higher in Polish boys and girls compared with their counterparts in the UK, Turkey and Canada and significantly lower than in children from the USA, Cyprus and Spain. The percentile curves for Polish children and youth, which were developed here for the first time, are base curves that can be applied in analysing trends as well as making comparisons with results of similar studies performed in other countries.

Mg2+ dependence of the structure and thermodynamics of wheat germ and lupin seeds 5S rRNA.

The formation and stability of structural elements in two 5S rRNA molecules from wheat germ (WG) and lupin seeds (LS) as a function of Mg2+ concentration in solution was determined using the adiabatic differential scanning microcalorimetry (DSC). The experimentally determined thermodynamic parameters are compared with calculations using thermodynamic databases used for prediction of RNA structure. The 5S rRNA molecules which show minor differences in the nucleotide sequence display very different thermal unfolding profiles (DSC profiles). Numerical deconvolution of DSC profiles provided information about structural transformations that take place in both 5S rRNA molecules. A comparative analysis of DSC data and the theoretical thermodynamic models of the structure was used to establish a relationship between the constituting transitions found in the melting profiles and the unfolding of structural domains of the 5S rRNA and stability of its particular helical elements. Increased concentrations of Mg2+ ions induces additional internal interactions stabilising 5S rRNA structures found at low Na+ concentrations. Observed conformational transitions suggest a structural model in which the extension of helical region E dominates over the postulated tertiary interaction between hairpin loops. We propose that helix E is stabilised by a sequence of non-standard pairings extending this helix by the formation of tetra loop e and an almost total reduction of loop d between helices E and D. Two hairpin structures in both 5S rRNA molecules: the extended C-C' and the extended E-E'-E" hairpins appear as the most stable elements of the structure. The cooperativity of the unfolding of helixes in these 5S rRNA molecules changes already at 2 mM Mg2+.

Biosynthesis of gibberellic acid (GA3) and mycotoxins by F. moniliforme sheldon and other species of Liseola section.

F. moniliforme and other species of Liseola section, F. culmorum, F. dlamini, and F. nygamai, were examined for their ability to produce gibberellic acid (GA3), fumonisins, trichothecenes, zearalenone, moniliformin, and bikaverin (TLC method). Gibberellic acid was produced by F. moniliforme strains in liquid medium and on rice kernels with a maximum concentration level of 470 mg/dm3 and 1 g/kg, respectively. No strain isolated in Poland produced GA3. High-yielding gibberellic acid strains produced neither trichothecenes and fumonisins nor other tested compounds. Also the rest of strains of examined species did not produce trichothecenes and other mycotoxins except for fumonisins which were found in rice cultures of F. moniliforme, F. proliferatum, and F. subglutinans. Bikaverin was produced by F. moniliforme always together with fumonisins. Filtrates of liquid cultures of gibberellin producing strains were tested for their toxicity to brine shrimps larvae (Artemia salina). It was found that GA3 presence does not increase toxicity of these filtrates.

Crystal structure of 2'-deoxycytidine hemidihydrogenphosphate reveals C+.C base pairs and tight, hydrogen-bonded (H2PO4-)infinity columns (1).

2'-Deoxycytidine hemidihydrogenphosphate has been crystallized in the hexagonal space group P6(2) with a = 25.839(3), c = 12.529(1) A. The structure has been solved using the Patterson search method. The asymmetric unit contains two protonated, base-paired 2'-deoxycytidine dimers and two H2PO4- anions. The C+.C base pairs are composed of a protonated and a neutral species each and are triple H-bonded, the central N(3) ... N(3) bonds being 2.850(7) and 2.884(5) A. The conformations of the four nucleosides fall in the same category (sugar puckers 2'-endo, glycosidic links anti) but in one of them the glycosidic torsion angle is quite low with consequences in other geometrical parameters. The H2PO4- anions are located on twofold axes and form two types of tight columns with P ... P separations about 4.18 A. The neighboring units along a column are linked via two very short O ... H ... O hydrogen bonds (O ... O about 2.49 A) leading to effective equalization of the P-O bonds. The base pairs of the two dC+.dC cations are coplanar and form layers perpendicular to the phosphate columns repeating every c/3. Within the layers, the dimers form a network through O(5') ... O(2) hydrogen bonds but their primary intermolecular interactions have the form of H-bond anchors [N(4)-H ... O-P and O(3')-H ... O-P] to the phosphate groups.

Comparative calorimetric studies on the dynamic conformation of plant 5S rRNA: II. Structural interpretation of the thermal unfolding patterns for lupin seeds and wheat germ.

Thermal unfolding of 5S rRNA from wheat germ (WG) and lupin seeds (LS) was studied in solution. Experimental curves of differential scanning calorimetry (DSC) were resolved into particular components according to the thermodynamic model of two-state transitions. The DSC temperature profiles for WG and LS differ significantly in spite of very high similarities in the sequence of both molecules. Those results are interpreted according to a model of the secondary and tertiary molecular structure of 5S rRNA. A comparison of the 'nearest neighbour' model of interaction with the experimental thermodynamic results enables a complete interpretation of the process of the melting of its structures. In light of our observations, the crucial differences between both DSC melting profiles are mainly an outcome of different thermodynamic properties of the first helical fragment 'A' made up of 9 complementary base pairs. It contains 6 differences in the nucleotide sequence of both types of molecules, which still retain 9-meric double helixes. The temperature stability of his helix in WG is much lower than of the LS one. Moreover, the results supply evidence for a strong specific tertiary interaction between the two hairpin loops 'c' and 'e' in both 5S rRNA molecules, modulated by small differences in the thermodynamic properties of both 5S rRNA.

Comparative calorimetric studies on the dynamic conformation of plant 5S rRNA. I. Thermal unfolding pattern of lupin seeds and wheat germ 5S rRNAs, also in the presence of magnesium and sperminium cations.

An attempt has been made to correlate differential scanning calorimetry melting profiles of 5S rRNAs from lupin seeds (L.s.) and wheat germ (W.g.) with their structure. It is suggested that the observed differences in thermal unfolding are due to differences in RNA nucleotide sequence and as a consequence in higher order structures. Interesting effects induced by magnesium cation, perprotonated and permethylated sperminium tetracations are discussed. It is suggested that the difference in the stabilizing effect of the three cations results from different mode of their interactions with RNA. "Pure" electrostatic interactions expected for permethylated tetracations are rather weak due to the steric hindrance around each positively charged nitrogen atom. Electrostatic interactions of the other two cations are significantly enhanced by coordination bonding for magnesium and by hydrogen bonding for protonated sperminium cation.

Mycotoxins in cereal grain. Part 12. Contamination with ochratoxin A and penicillic acid as indicator of improper storage of cereal grain.

Formation of ochratoxin A and penicillic acid in wheat kernels at 6 moisture levels: 15, 18, 21, 24, 27 and 30% at 15 degrees C has been examined during 4 months of storage. The minimum time for formation of significant amount (0.5-1 mg/kg) of ochratoxin A and penicillic acid (6-8 mg/kg) in stored grain has been found for the various water contents as follows: 18%-16 weeks, 21%-6 weeks, 24% and more - 2 weeks. At 15% of moisture content formation of ochratoxin A and penicillic acid was not observed until 4 months of storage.

Ochratoxin A formation by isolated strains of the conidial stage of Aspergillus glaucus Link ex Grey (= Eurotium herbariorum Wiggers Link ex Gray) from cereal grains.

Two strains of Aspergillus glaucus Link ex Grey (= Eurotium herbariorum (Wiggers Link ex Grey] out of 15 isolated from cereals formed ochratoxin A during growth on autoclaved kernels of wheat and corn, with yields from 0.8 to 2.5 mg/kg of culture.

Comparative structural analysis of cytidine, ethenocytidine and their protonated salts III. 1H, 13C and 15N NMR studies at natural isotope abundance.

The 1H, 13C, 15N NMR spectra of cytidine /Cyd/, ethenocytidine /epsilon Cyd/ and their hydrochlorides /Cyd X HC1/ and /epsilon Cyd X HC1/ have been analysed to compare structural differences observed in solution with those existing in the crystalline state. The effects of ethenobridging and protonation of the hertero-aromatic base on the intramolecular stereochemistry, intermolecular interactions and electronic structure of the whole molecule are discussed on the basis of the NMR studies in DMSO solutions. Particular interest is devoted to the discussion of the conformation of the ribose ring, the presence of the intramolecular C-5'-0...H-6-C hydrogen bond, unambiguous assignment of the site of protonation, the mechanism of the 5C-H deuterium exchange in Cyd X HC1, and the intermolecular interactions in solution.

Mycotoxins in cereal grain. Part IX. Zearalenone and Fusaria in wheat, barley, rye and corn kernels.

Toxigenic Fusaria, producing zearalenone, appeared in 31% of cereal grain samples. However zearalenone was present only in 0.5% of 584 cereal samples assayed during 1979-1981 at level 0.2-1.2 mg/kg. Fungi able to form zearalenone were present mainly in grain collected from breeding stations. Fusarium culmorum was dominant among toxigenic isolates from domestic cereals and yield of zearalenone was up to 700 mg/kg.

Mycotoxins in cereal grain. Part VIII. Microbiological evaluation of cereal grain quality, connected with mycotoxins occurrence.

Four classes of microbiological quality of cereal grain are proposed. For classification the frequency of kernels contamination with Penicillia, Aspergilli and Phycomycetes is considered as essential. Lots contaminated with mycotoxins (ochratoxins) were usually of IIIrd and IVth class of quality.

Mycotoxins in cereal grain. Part 5. Changes of cereal grain biological value after ammoniation and mycotoxins (ochratoxins) inactivation.

Ammoniation was proved to be a suitable detoxification procedure to remove toxicity of Aspergillus ochraceus mycotoxins (mainly ochratoxin A) from contaminated cereal grain (corn, wheat and barley). It was found that ammoniation should be performed to achieve decomposition of ochratoxin A to nondetectable level. Ammoniated grain can be used as feedstuff component without essential change of nutritive value during ammoniation.

Mycotoxins in cereal grain. Part IV. Inactivation of ochratoxin A and other mycotoxins during ammoniation.

Addition of ammonia to final concentration 2% inactivates ochratoxin A, aflatoxin, citrinin, penicillic acid and partially zearalenon at temperature 20-50 degrees C. Detoxification of contaminated cereal grain (wheat, corn or barley) can be performed on a farm using ammoniation without special investment during 4 to 6 weeks. Ammoniation changes nutritional value of grain as feed in a small extent.