The effect of ozone on the yellowing process of magnesium-deficient clonal Norway spruce grown under defined conditions.

During two vegetation periods, young clonal spruce trees (Picea abies (L.) Karst.) with sufficient and poor magnesium (Mg) supply were exposed in the environmental chambers of the GSF phytotron to three levels of ozone (daily means: 18-22, 88-130, and 135-190 microg m(-3); 10% reduction at night). Previous year's needles were examined at 4-week intervals with respect to their contents of Mg, Ca, K, Mn, N, P, and chlorophyll (Chl), various parameters of Chl fluorescence, and the stability of the isolated light-harvesting Chl-a/b-protein complex LHC II. The needles of the two nutrition variants contained more than 0.53 or less than 0.27mg Mg g(-1) needle dry matter, respectively. The ratio of variable to maximal Chl-a fluorescence of the dark-adapted needles, Fv/Fm, and the photoinhibitory quenching of Fv after light treatment, SVi.v, were affected by the Mg content of the needles rather than the ozone levels. Changes of the Chl content and the behavior of the LHC II allowed differentiating between a slow process of needle yellowing occurring under Mg deficiency only, and a rapid process of needle yellowing occurring under the combined action of Mg deficiency and ozone pollution. Only the rapid yellowing process was accompanied by destabilization of the LHC II, and the degree of destabilization was correlated with the ozone concentration present in the days before sampling. The results are consistent with observations obtained at a research site in the Central Black Forest (J Plant Physiol 161 (2004) 423).

Trace and mineral elements in royal jelly and homeostatic effects.

Royal jelly from Apis mellifera is a highly active natural biological substance and is probably one of the most interesting raw substances in natural product chemistry. Trace elements play a key role in the biomedical activities associated with royal jelly, as these elements have a multitude of known and unknown biological functions. For this reason concentrations of 28 trace (Al, Ba, Sr, Bi, Cd, Hg, Pb, Sn, Te, Tl, W, Sb, Cr, Ni, Ti, V, Co, Mo) and mineral (P, S, Ca, Mg, K, Na, Zn, Fe, Cu, Mn) elements were systematically investigated in botanically and geologically defined royal jelly samples. In addition, concentrations of 14 trace elements were measured in the associated honey samples--honey being the precursor of royal jelly. Concentrations of K, Na, Mg, Ca, P, S, Cu, Fe, Zn, Al, Ba and Sr in royal jelly were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES), while concentrations of Bi, Cd, Hg, Pb, Sn, Te, Tl, W, Sb, Cr, Mn, Ni, Ti, V, Co and Mo in royal jelly were determined by double focusing magnetic sector field inductively coupled plasma mass spectrometry (SF-ICP-MS). In the honey samples, trace and mineral element concentrations strongly depended on botanical and geological origin, and substantial variation was found. In contrast, the concentrations of trace and mineral elements were highly constant in the associated royal jelly samples. The most important results were the homeostatic adjustments of trace and mineral element concentrations in royal jelly. This effect was evidently produced in the endocrine glands of nurse bees, which are adapted for needs of bee larvae. In conclusion, this research yielded a surprising and completely new finding--that royal jelly, as a form of lactation on the insect level, shows the same homeostatic adjustment as mammalian and human breast milk.

Elemental and ion composition of exhaled air condensate in cystic fibrosis.

BACKGROUND: In cystic fibrosis (CF) the exact ion composition of the airway surface fluid is still debated and it is not clear if it differs from healthy subjects. The air that we exhale contains small droplets, which are generated by shear forces from the airway surface fluid and very likely mirror its ion composition. We hypothesized that differences between CF-patients and healthy controls would be reflected by differences in their exhaled air. METHODS: In nasally collected exhaled breath condensate from 20 children and young adults with cystic fibrosis and 20 healthy subjects, the elements and anions were determined by optical emission spectroscopy and ion-exchange chromatography. RESULTS: The concentrations of the major components Na and Cl- did not differ, Zn was higher and NO3- was lower in CF-patients. During a given time period, CF-patients produced a slightly larger volume of breath condensate and they exhaled more Na, K and Zn. Fluoride was detected in half of all samples, whereas copper, iron, magnesium, phosphorus and sulfur were present only sporadically, with no differences. CONCLUSIONS: These data detail the composition of exhaled breath condensate and suggest a similar Na and Cl- concentration in CF-airway surface fluid as in healthy subjects.

Investigations on the solubility of corrosion products on depleted uranium projectiles by simulated body fluids and the consequences on dose assessment.

Ingestion and inhalation of corrosion products covering weathered penetrators made of depleted uranium (DU) represent potential radiological exposure pathways. In order to study the bioavailability of these corrosion products, their solubility was determined using simulated gastric and pulmonary juices. About 75 and 36% of the uranium in the corrosion products were found to be soluble in simulated gastric and pulmonary juices, respectively. The effective dose coefficient for adults after ingestion was calculated to be 0.61 muSv mg(-1) DU. This compares to an effective dose coefficient for an adult of 0.71 muSv mg(-1) for DU materials given by the World Health Organization (WHO). The effective dose coefficient for inhalation was calculated to be 3.7 x 10(-6 )Sv Bq(-1) for workers and 5.3 x 10(-6 )Sv Bq(-1) for members of the public, respectively, which is between those of particles of Types M and S as defined by the International Commission on Radiological Protection (ICRP). The speciation of the corrosion products was investigated by time-of-flight secondary ion mass spectrometry (TOF-SIMS). The mean oxidation state of uranium was found to be 4.6, which suggests that the uranium in the corrosion products consists of a mixture of U(IV) and U(VI) species.

Caesium-affected gene expression in Arabidopsis thaliana.

* Excessive caesium can be toxic to plants. Here we investigated Cs uptake and caesium-induced gene expression in Arabidopsis thaliana. * Accumulation was measured in plants grown for 5 wk on agar supplemented with nontoxic and up to toxic levels of Cs. Caesium-induced gene expression was studied by suppression-subtractive hybridization (SSH) and RT-PCR. * Caesium accumulated in leaf rosettes dependent upon the external concentration in the growth media, whereas the potassium concentration decreased in rosettes. At a concentration of 850 microM, Cs plants showed reduced development, and withered with an increase in concentration to 1 mM Cs. SSH resulted in the isolation of 73 clones that were differentially expressed at a Cs concentration of 150 microM. Most of the genes identified belong to groups of genes encoding proteins in stress defence, detoxification, transport, homeostasis and general metabolism, and proteins controlling transcription and translation. * The present study identified a number of marker genes for Cs in Arabidopsis grown under nontoxic Cs concentrations, indicating that Cs acts as an abiotic stress factor.

Studies of strontium biokinetics in humans. Part 1: optimisation of intrinsic labelling of foodstuffs with stable isotopes of strontium.

The radioactive isotopes of strontium, mainly (90)Sr, which are common fission products, may significantly contribute to the internal exposure of the population in case of their accidental release into the environment and transfer to the food chain. For (90)Sr, the internal radiation dose is significantly dependent on the fractional absorption of the ingested activity (f(1)-value). Human data on the absorption of dietary strontium and of soluble forms of the element give values ranging from about 0.15 to 0.45 (up to 1.0) for adults. The International Commission on Radiological Protection (ICRP) has adopted f(1)-values of 0.6 for children of less than 1 year of age, 0.4 for children between 1 and 15 years and 0.3 for adolescents above 15 years of age. This study was aimed at investigating how far these values correspond to the actual uptake of strontium from contaminated foodstuffs. A methodology is presented that has been developed for preparing foodstuffs intrinsically labelled with stable isotopes and that will be used in tracer kinetic investigations. The results show that cress and salad can be adequately labelled, i.e. a strontium concentration of 1.36+/-0.47 g per kg of cress (wet weight) and of 0.29+/-0.04 g per kg of salad (wet weight) may be obtained within 15 days and 24 days, respectively. For the biokinetic investigations on humans, applying stable isotopes of Sr as tracers, about 0.1-1 mg strontium is required per volunteer, i.e. a few grams of the edible parts of the labelled material are sufficient.

Release of toxic metals from button batteries retained in the stomach: An in vitro study.

BACKGROUND: Ingestion of button batteries by children is a rapidly growing problem, and opinions differ on how button batteries distal to the gastroesophageal junction should be managed. The authors therefore performed an experimental study to determine the cumulative load of various toxic elements released from retained button cells in simulated gastric juice. METHODS: Eight different groups of button cells were immersed in simulated gastric juice. Analyzed elements included Al, Ba, Cd, Cr, Cu, Fe, Hg, Li, Mg, Mn, Ni, Pb, Sb, Sn, Sr, Te, TI, V, W; and Zn. Inductively coupled plasma mass spectrometry (ICP-MS) was used to evaluate the residual amounts of elements after 4, 24, 72, and 120 hours. RESULTS: At 4 hours, leakage was seen with almost all batteries, with the levels increasing in a time-dependent manner. The highest detected levels at 4 hours were 1.20 microgram for Cd, 280.51 ng for Hg, and 2.63 microgram for Pb. Dissolution, holes, and defragmentation were seen within 24 to 72 hours. Battery weight loss varied between 22 and 104 mg over the course of the study. CONCLUSIONS: Toxic elements contained in button cells are released quickly in gastric juice. This finding might change the current policy of watchful waiting or conservative management of batteries lodged in the stomach.

Studies of strontium biokinetics in humans. Part 2: uptake of strontium from aqueous solutions and labelled foodstuffs.

The accidental release of radioactive isotopes of strontium, mainly (90)Sr, into the environment and its transfer into the biosphere results in an internal radiation exposure of the affected population. In order to obtain reliable estimates of the committed dose due to an intake of Sr radionuclides, reliable information on its metabolic behaviour inside the human body is needed, i.e. biokinetic data on fractional uptake from contaminated foodstuffs, distribution to and retention in different organs and tissues of the human body. Such information can be obtained by tracer kinetic investigations. The committed effective dose is dependent on the fractional intestinal absorption of the ingested activity (f(1) value). The International Commission on Radiological Protection in its publication ICRP 67 adopted an f(1) value of 0.3 for adults. This study is aimed at investigating if the value corresponds with the actual uptake from contaminated foodstuffs. Aqueous solutions and contaminated vegetables, i.e. cress and salad (lettuce) were used as test materials. For this purpose, the methodology for intrinsic labelling of foodstuffs described in part 1 was applied. For aqueous solutions, a mean f(1) value of 0.63+/-0.14 (mean +/- SD) was obtained by administering 1 mg of strontium. The uptake of Sr from cress intrinsically labelled with about 1 mg Sr almost corresponds to that from aqueous solutions (f(1)=0.62+/-0.10), but from lettuce it is reduced by a factor of 2 (f(1)=0.27+/-0.08).

Age-related reference values for serum selenium concentrations in infants and children.

BACKGROUND: Children are at particular risk for selenium deficiency, which has potentially serious medical implications. Reliable age-specific reference values for serum selenium concentrations in children are sparse, but are essential for the identification of selenium deficiency and decisions regarding selenium supplementation. METHODS: Using electrothermal atomic absorption spectrometry, we analyzed serum selenium concentrations from 1010 apparently healthy children (age range, 1 day to 18 years) and from 60 patients on a protein-restricted diet because of inborn errors of metabolism. Reference intervals were defined according to recommended guidelines. RESULTS: Medians for serum selenium concentrations showed a statistically significant age dependency: a decrease from the age <1 month (0.64 micromol/L) to 4 months (0.44 micromol/L); an increase to 0.62 micromol/L in the 4-12 months age group; constant values in children between 1 and 5 years of age (0.90 micromol/L); and an additional slight increase to reach a plateau between 5 and 18 years (0.99 micromol/L). Of 43 children older than 1 year and on a protein-restricted diet, 87% showed serum selenium concentrations below the 2.5 percentile. CONCLUSIONS: Because of nutritional changes, serum selenium concentrations are significantly higher in older children than in infants under 1 year of age. The application of age-adjusted reference values may provide more specific criteria for selenium supplementation. Long-term protein restriction in children is reflected by a failure to achieve higher serum selenium concentrations with increasing age.

Oxidative damage is increased in human liver tissue adjacent to hepatocellular carcinoma.

Accumulation of genetic alterations in hepatocarcinogenesis is closely associated with chronic inflammatory liver disease. 8-oxo-2'-deoxyguanosine (8-oxo-dG), the major promutagenic DNA adduct caused by reactive oxygen species (ROS), leads to G:C --> T:A transversions. These lesions can be enzymatically repaired mainly by human MutT homolog 1 (hMTH1), human 8-oxo-guanine DNA glycosylase (hOGG1) and human MutY homolog (hMYH). The aim of this study was to evaluate the extent of oxidative damage and its dependence on the cellular antioxidative capacity and the expression of specific DNA repair enzymes in tumor (tu) and corresponding adjacent nontumor (ntu) liver tissue of 23 patients with histologically confirmed hepatocellular carcinoma. 8-oxo-dG levels, as detected by high-pressure liquid chromatography with electrochemical detection, were significantly (P =.003) elevated in ntu tissue (median, 129 fmol/microg DNA) as compared to tu tissue (median, 52 fmol/microg DNA), and were closely associated with inflammatory infiltration. In ntu tissue, the hepatic iron concentration and malondialdehyde levels were significantly (P =.001) higher as compared to tu tissue. Glutathione content, glutathione peroxidase activity and manganese superoxide dismutase messenger RNA (mRNA) expression did not show statistical differences between ntu and tu tissue. Real-time reverse transcription polymerase chain reaction revealed in tu tissue significantly (P =.014) higher hMTH1 mRNA expression compared to ntu tissue. In contrast, hMYH mRNA expression was significantly (P <.05) higher in ntu tissue. No difference in hOGG1 mRNA expression was seen between tu and ntu. In conclusion, these data suggest that ROS generated by chronic inflammation contribute to human hepatocarcinogenesis. The role of DNA repair enzymes appears to be of reactive rather than causative manner.