Normative data for lung function and exhaled nitric oxide in unsedated healthy infants.

Despite association with lung growth and long-term respiratory morbidity, there is a lack of normative lung function data for unsedated infants conforming to latest European Respiratory Society/American Thoracic Society standards. Lung function was measured using an ultrasonic flow meter in 342 unsedated, healthy, term-born infants at a mean ± sd age of 5.1 ± 0.8 weeks during natural sleep according to the latest standards. Tidal breathing flow-volume loops (TBFVL) and exhaled nitric oxide (eNO) measurements were obtained from 100 regular breaths. We aimed for three acceptable measurements for multiple-breath washout and 5-10 acceptable interruption resistance (R(int)) measurements. Acceptable measurements were obtained in ≤ 285 infants with high variability. Mean values were 7.48 mL·kg⁻¹ (95% limits of agreement 4.95-10.0 mL·kg⁻¹) for tidal volume, 14.3 ppb (2.6-26.1 ppb) for eNO, 23.9 mL·kg⁻¹ (16.0-31.8 mL·kg⁻¹) for functional residual capacity, 6.75 (5.63-7.87) for lung clearance index and 3.78 kPa·s·L⁻¹ (1.14-6.42 kPa·s·L⁻¹) for R(int). In males, TBFVL outcomes were associated with anthropometric parameters and in females, with maternal smoking during pregnancy, maternal asthma and Caesarean section. This large normative data set in unsedated infants offers reference values for future research and particularly for studies where sedation may put infants at risk. Furthermore, it highlights the impact of maternal and environmental risk factors on neonatal lung function.

Phenotypic plasticity of Senecio vulgaris from contrasting habitat types: growth and pyrrolizidine alkaloid formation.

The growth-differentiation balance hypothesis (GDB), which postulates a physiological trade-off between growth and differentiation (morphological and chemical), has been tested almost exclusively for carbon-based secondary metabolites. Little attention has been paid to N-based compounds. In this study we aimed to test the predictions of the GDB hypothesis under field conditions for growth and pyrrolizidine alkaloid (PA) formation in Senecio vulgaris. We conducted a reciprocal transplant experiment at two sites differing widely in their nutrient supply. These included a conventionally managed vineyard (V) and a strip of local wild flowers between crop fields, which was established to promote species diversity in agroecosystems (C). No fertilizer or pesticides are allowed in such ecological compensation areas. In C, we expected lower growth but higher PA formation than in V. Due to differentiated selection regimes in the two habitat types with regard to nutrient (nitrogen) availability in the soil, we also expected different N-allocation patterns for the genotypes of the two collection sites. Plants of V produced more biomass and were taller than the plants of C. The relatively poor nitrogen conditions in C favored an earlier differentiation towards generative organs. In plants of C, higher concentrations of PAs were found than in plants of V. There exists a close negative correlation between growth and PA formation, indicating a trade-off. The origin of the plant material had only a little effect on PA formation. The observed phenotypic reaction of PA formation in S. vulgaris in the two habitats fits quite well the predictions of GDB theory. It is shown that this general response is overlaid by physiological factors leading to a pattern of PA accumulation, which is not readily predictable by nonmechanistic theories.

Selected phenolic compounds in cultivated plants: ecologic functions, health implications, and modulation by pesticides.

Phenolic compounds are widely distributed in the plant kingdom. Plant tissues may contain up to several grams per kilogram. External stimuli such as microbial infections, ultraviolet radiation, and chemical stressors induce their synthesis. The phenolic compounds resveratrol, flavonoids, and furanocoumarins have many ecologic functions and affect human health. Ecologic functions include defense against microbial pathogens and herbivorous animals. Phenolic compounds may have both beneficial and toxic effects on human health. Effects on low-density lipoproteins and aggregation of platelets are beneficial because they reduce the risk of coronary heart disease. Mutagenic, cancerogenic, and phototoxic effects are risk factors of human health. The synthesis of phenolic compounds in plants can be modulated by the application of herbicides and, to a lesser extent, insecticides and fungicides. The effects on ecosystem functioning and human health are complex and cannot be predicted with great certainty. The consequences of the combined natural and pesticide-induced modulating effects for ecologic functions and human health should be further evaluated.

Purine alkaloid formation and CO2 gas exchange in dependence of development and of environmental factors in leaves of Coffea arabica L.

In the leaves of Coffea arabica L., purine alkaloid formation was estimated by analyzing the theobromine and caffeine content and by measuring the methylation rate of [2-(14)C]theobromine to [2-(14)C]caffeine in short-term experiments (6-24 h). At the same time, growth (in terms of dry weight and area), net photosynthesis (NPS), and dark respiration were determined. During leaf development, which was considered to be terminated when NPS was at a maximum (60-80 µmol g(-1) s(-1)) and dark respiration at a minimum (5-7.5 µmol g(-1) s(-1)), the content of theobromine and the velocity of caffeine formation were both found to decrease by a factor of more than 100. The close correlation between the theobromine content and the methylation rate is suspended when purine alkaloid formation is influenced by factors other than leaf development. Among these factors, temperature is the most effective: the velocity of caffeine biosynthesis is increased by raising the temperature and vice versa. Although the plants were well irrigated, a drastic decrease of NPS in the afternoon was observed under all environmental conditions tested. Light saturation was reached between 170-360 µmol m(-2) s(-1). The temperature optimum of NPS was shown to be very broad (24-33°C)m provided the adaptation time was sufficiently long.