Helicobacter pylori prevalences and risk factors among school beginners in a German urban center and its rural county

In 1998, the Helicobacter pylori [(13)C]urea breath test was offered to all school beginners (birth cohort 1991/1992) in the city of Leipzig and in Leipzig County, Germany, to determine the colonization prevalence and potential transmission pathways of the bacterium. A total of 3,347 school beginners participated in the test, and 2,888 parents completed the detailed, self-administered questionnaire. The H. pylori prevalence was 6.5% [95% confidence interval (CI), 5.3-7.6] in the city and 5.7% (CI, 4.2-7.0) in the county. Using cluster analysis (WARD's method, Euclidean distances), we identified different sets of variables (confirmed by multivariate logistic regression analyses [odds ratios (ORs)] that are signficantly associated with H. pylori positivity. Among city children, the risk is significantly increased with contact to a pet hamster (OR = 2.4; 95% CI, 1.2-4.7; p < 0.015) and travels to Asian countries (OR = 3.7; 95% CI, 1.6-8.7; p < 0.002). Among county children, H. pylori positivity increased significantly with drinking of water from nonmunicipal sources (OR = 16.4; 95% CI, 3.1-88.5; p < 0.001), more than 3 children living in a household (OR = 4.2; 95% CI, 1.2-14.6; p < 0.02), and contact with pet hamsters (OR = 2.4; 95% CI, 1.0-5.7; p < 0.04). These data suggest that, in a general population sample, indirect fecal-oral transmission and living conditions are important risk factors in the spread of H. pylori infection. However, clinical symptoms do not necessarily indicate H. pylori positivity.

Pulmonary function and urban air pollution in preschool children

Epidemiologic evidence indicates that respiratory disease in infancy and childhood has respiratory health consequences in later life. Pulmonary function is considered a good index of early effects. This study assessed the relationship of pulmonary function in preschool children in Leipzig, Germany, and exposure to high levels of air pollution during early childhood. Spirometric measures were taken of 235 preschoolers (126 boys, 109 girls, mean age 5.1 +/- 1.3 years) attending 16 randomly selected daycare centres, using the 'Bosch Spiro 501' spirometer. The results showed decrements in the average FVC (85.5% predicted [pred]) and FEV1 (90.2% pred) differing with spatial variations in the ambient air pollution burden of the children's residential area. Exposure to a pollution profile of heavy traffic and/or domestic heating showed markedly lower FVC (78.9% and 85.5% pred, respectively) and FEV1 (82.4% and 88.5% pred). Miller's Diagnostic Quadrant Model of Disease Classification, categorizing pulmonary function data for preliminary diagnostic purposes, assessed the lung function values (FVC% pred/relative FEV1 [FEV1/FVC]%) of a significant number of children as 'restrictions' (n = 52; 22.1%). Summarizing: variations in spirometric indices were observed across exposure groups with a significant number of children showing signs of a restrictive ventilatory function. These cross-sectional data, however, do not permit to conclude with any degree of certainty that this is indicative of an early sign of a functional deficit.

Oxygen fixation into hydroxyproline in etiolated maize seedlings : verification by tandem mass spectrometry

Etiolated maize (Zea mays L.) seedlings were grown in the dark for 5 days in an atmosphere enriched with 10.0 atom% (18)O(2). Hydroxyproline was isolated from root and shoot tissues, purified, and methylated. It was not possible to determine (18)O incorporation into hydroxyproline by conventional mass spectrometry because the final product was not sufficiently pure. The final product was analyzed successfully by tandem mass spectrometry. The (18)O content of the hydroxyl oxygen atom was 10 +/- 0.7 atom%. This result demonstrates that the hydroxyl oxygen atom in hydroxyproline was derived exclusively from molecular oxygen.

Photosynthetic and Carbohydrate Metabolism in Isolated Leaf Cells of Digitaria pentzii

Mesophyll cells and bundle sheath strands were isolated rapidly from leaves of the C(4) species Digitaria pentzii Stent. (slenderstem digitgrass) by a chopping and differential filtration technique. Rates of CO(2) fixation in the light by mesophyll and bundle sheath cells without added exogenous substrates were 6.3 and 54.2 micromoles of CO(2) per milligram of chlorophyll per hour, respectively. The addition of pyruvate or phosphoenolpyruvate to the mesophyll cells increased the rates to 15.2 and 824.6 micromoles of CO(2) per milligram of chlorophyll per hour, respectively. The addition of ribose 5-phosphate increased the rate for bundle sheath cells to 106.8 micromoles of CO(2) per milligram of chlorophyll per hour. These rates are comparable to those reported for cells isolated by other methods. The K(m)(HCO(3) (-)) for mesophyll cells was 0.9 mm; for bundle sheath cells it was 1.3 mm at low, and 40 mm at higher HCO(3) (-) concentrations. After 2 hours of photosynthesis by mesophyll cells in (14)CO(2) and phosphoenolpyruvate, 88% of the incorporated (14)C was found in organic acids and 0.8% in carbohydrates; for bundle sheath cells incubated in ribose 5-phosphate and ATP, more than 58% of incorporated (14)C was found in carbohydrates, mainly starch, and 32% in organic acids. These findings, together with the stimulation of CO(2) fixation by phosphoenolpyruvate for mesophyll cells and by ribose 5-phosphate plus ATP for bundle sheath cells, and the location of phosphoenolpyruvate and ribulose bisphosphate carboxylases in mesophyll and bundle sheath cells, respectively, are in accord with the scheme of C(4) photosynthesis which places the Calvin cycle in the bundle sheath and C(4) acid formation in mesophyll cells.Starch and reducing sugars were present in both mesophyll and bundle sheath cells following a period of photosynthesis by whole leaves. However, when isolated cells were exposed to (14)CO(2) in the light, even with appropriate exogenous substrates, only bundle sheath cells accumulated appreciable amounts of labeled carbohydrates. Incubation of mesophyll cells in the light with ATP and either pyruvate and inorganic phosphate, or phosphoenolpyruvate, or 3-phosphoglycerate resulted in large increases in total carbohydrates. The 3-phosphoglycerate treatment produced the greatest increase. These results could not be explained on the basis of increased CO(2) fixation. They suggest that mesophyll cells are able to metabolize exogenously supplied 3-carbon compounds to carbohydrates, despite the apparent inability of these cells to utilize CO(2) for this purpose, and support the view that in the whole leaf 3-phosphoglycerate is transported from bundle sheath to mesophyll cells, where it is reduced to carbohydrate.Sucrose and sucrose-phosphate synthetases and invertase were localized mainly in bundle sheath cells. ADP-Glucose starch synthetase and amylase were present mainly in bundle sheath cells whereas starch phosphorylase was present mainly in mesophyll cells.

Role of oxygen fixation in hydroxyproline biosynthesis by etiolated seedlings

Etiolated maize and soybean seedlings were grown for several days in atmospheres enriched with O(18). Hydroxyproline subsequently isolated from the seedlings by column and thin-layer chromatography was labeled with excess O(18), but proline was not. Control experiments in which seedlings were grown in H(2)O(18) and unlabeled atmospheres demonstrated that neither proline nor hydroxyproline was labeled with excess O(18). It was concluded that oxygen fixation is an essential feature of hydroxyproline biosynthesis in these seedlings, and that the hydroxyl oxygen atom in hydroxyproline is derived from molecular oxygen and not from water; similar results have been reported previously for sycamore cell suspensions.