No effects of short-term GSM mobile phone radiation on cerebral blood flow measured using positron emission tomography

The present study investigated the effects of 902.4 MHz Global System for Mobile Communications (GSM) mobile phone radiation on cerebral blood flow using positron emission tomography (PET) with the ¹⁵O‐water tracer. Fifteen young, healthy, right‐handed male subjects were exposed to phone radiation from three different locations (left ear, right ear, forehead) and to sham exposure to test for possible exposure effects on brain regions close to the exposure source. Whole‐brain [¹⁵O]H₂O–PET images were acquired 12 times, 3 for each condition, in a counterbalanced order. Subjects were exposed for 5 min in each scan while performing a simple visual vigilance task. Temperature was also measured in the head region (forehead, eyes, cheeks, ear canals) during exposure. The exposure induced a slight temperature rise in the ear canals but did not affect brain hemodynamics and task performance. The results provided no evidence for acute effects of short‐term mobile phone radiation on cerebral blood flow. Bioelectromagnetics 33:247–256, 2012. © 2011 Wiley Periodicals, Inc.     

In vitro seed maturation in Brassica rapa L.: Relationship of silique atmosphere to storage reserve deposition

The Brassica rapa L. silique is a self-contained environment that maintains hypoxia around the developing seeds, and in which carbon dioxide accumulates to very high concentrations (>30,000 ppm). How the silique microenvironment modulates the composition and amount of storage reserves in the seeds is of interest because of the important agricultural role played by canola (B. rapa and Brassica napus) as an oilseed. Because of the small volume and dynamic nature of this microenvironment in Brassica, a standardized system was needed to study the environmental role played in storage reserve deposition. For this purpose we have developed a silique culture system that permits maturation of seed in vitro. Siliques excised from plants just 11 days after pollination complete the ripening of their seeds after 20 days of culture in light (200 μmol/m²/s) on MS medium containing 30 g/l sucrose, 0.25 mg/l BAP, and 0.025 mg/l NAA. Cytochemical localization and biochemical analyses revealed that storage reserves were affected by the in vitro maturation system. Although following a comparable ripening timeline to that occurring on the plant, and producing fully germinable seeds, in vitro maturation resulted in a 40% reduction in seed weight and the mature seeds contained decreased lipid, but increased protein, starch and soluble carbohydrates. To study the internal atmosphere surrounding the seeds, we developed a method to capture silique gases in helium with subsequent quantification of O₂ and CO₂ in the sample by gas chromatography. Analysis of the internal silique atmosphere showed that in vitro siliques provided seeds with a less oxygenated environment than they experience attached to the plant. Carbon dioxide concentrations remained high later into the maturation sequence in vitro than on the plant. When sampling gases from siliques attached to plants, we found multiple samples from the same plant resulted in higher variance than when only a single silique was sampled, suggesting that connection to the plant directly influences internal silique gases. Lower O₂ in the in vitro siliques was correlated with depressed lipid content in their mature seeds, supporting the conclusion that oxygen availability limits lipid accumulation. Previous studies showed how environmental factors influence Brassica embryos grown in tissue culture. These systems fail to preserve the component of metabolic regulation that is enforced by the silique wall tissues. Our in vitro maturation system provides a useful tool for specialized investigations since both the gaseous and hormonal environments can be readily manipulated.     

Complex phenotypic profiles leading to ozone sensitivity in Arabidopsis thaliana mutants

Genetically tractable model plants offer the possibility of defining the plant O₃ response at the molecular level. To this end, we have isolated a collection of ozone (O₃)-sensitive mutants of Arabidopsis thaliana . Mutant phenotypes and genetics were characterized. Additionally, parameters associated with O₃ sensitivity were analysed, including stomatal conductance, sensitivity to and accumulation of reactive oxygen species, antioxidants, stress gene-expression and the accumulation of stress hormones. Each mutant has a unique phenotypic profile, with O₃ sensitivity caused by a unique set of alterations in these systems. O₃ sensitivity in these mutants is not caused by gross deficiencies in the antioxidant pathways tested here. The rcd3 mutant exhibits misregulated stomata. All mutants exhibited changes in stress hormones consistent with the known hormonal roles in defence and cell death regulation. One mutant, dubbed re-8 , is an allele of the classic leaf development mutant reticulata and exhibits phenotypes dependent on light conditions. This study shows that O₃ sensitivity can be determined by deficiencies in multiple interacting plant systems and provides genetic evidence linking these systems.     

What Data to Use for Forest Conservation Planning? A Comparison of Coarse Open and Detailed Proprietary Forest Inventory Data in Finland

The boreal region is facing intensifying resource extraction pressure, but the lack of comprehensive biodiversity data makes operative forest conservation planning difficult. Many countries have implemented forest inventory schemes and are making extensive and up-to-date forest databases increasingly available. Some of the more detailed inventory databases, however, remain proprietary and unavailable for conservation planning. Here, we investigate how well different open and proprietary forest inventory data sets suit the purpose of conservation prioritization in Finland. We also explore how much priorities are affected by using the less accurate but open data. First, we construct a set of indices for forest conservation value based on quantitative information commonly found in forest inventories. These include the maturity of the trees, tree species composition, and site fertility. Secondly, using these data and accounting for connectivity between forest types, we investigate the patterns in conservation priority. For prioritization, we use Zonation, a method and software for spatial conservation prioritization. We then validate the prioritizations by comparing them to known areas of high conservation value. We show that the overall priority patterns are relatively consistent across different data sources and analysis options. However, the coarse data cannot be used to accurately identify the high-priority areas as it misses much of the fine-scale variation in forest structures. We conclude that, while inventory data collected for forestry purposes may be useful for forest conservation purposes, it needs to be detailed enough to be able to account for more fine-scaled features of high conservation value. These results underline the importance of making detailed inventory data publicly available. Finally, we discuss how the prioritization methodology we used could be integrated into operative forest management, especially in countries in the boreal zone.     

Alternative model and approach for determining microbial heterotrophic activities in aquatic systems.

Increasing amounts of high-specific-activity tritiated organic compounds were added to samples of several natural waters such that in situ substrate concentrations might be approximated. The uptake responses by the native heterotrophic microflora suggested that (i) heterotrophic populations metabolize the added nutrients, but (ii) these responses are not necessarily a reflection of Michaelis-Menten enzyme kinetics. The uptake kinetics appeared to be due to dilution of the naturally occurring metabolite by added radioactive substrate and physiological responses of the microflora to organic enrichment.     

Dietary exposure of Finnish children to heavy metal mixture – a cumulative assessment

A preliminary assessment of the cumulative exposure to heavy metals among Finnish preschool children is reported. Cadmium, lead, arsenic,and mercury affect many of the same organs in the human body. The effects are mostly caused by oxidative stress or disruption of enzyme function. The cumulative effects of the heavy metals on the central nervous system and on the kidneys are determined based on national concentration and consumption data, and comparison of the relative toxicity of the heavy metals is based on dose–response values found in the literature. The cumulative effects were assumed to be additive. The main contributors to kidney toxicity among the studied population groups were cadmium and lead, while lead was the main contributor to neurotoxic effects.     

Short and long term regulation of catecholamine biosynthetic enzymes by angiotensin in cultured adrenal medullary cells. Molecular mechanisms and nature of second messenger systems

The purpose of this study was to examine the effects of angiotensin on the enzyme activities and gene expression of two catecholamine synthesizing enzymes, tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT), in bovine adrenal medullary (AM) cells. Short term (15 min) incubation of cultured AM cells with 2 nM [Sar1]angiotensin II (s1-AII) did not increase basal secretion of catecholamines; however, longer incubations (3, 24, or 72 h) produced 4-10-fold increases. To determine whether angiotensin affects synthesis of catecholamines, the activities of TH and PNMT were examined. Incubation with s1-AII (15-30 min) decreased the Km of TH for its biopterine cofactor [6R)-5,6,7,8-tetrahydro-1-biopterin dihydrochloride (BH4] without affecting the Vmax, suggesting activation of TH. After long term incubation (72 h) the Km value was identical to that of control, while increases in the apparent Vmax were observed. PNMT activity was unaffected during a 30-min treatment with s1-AII; however, 2-fold increases occurred after a 48-72-h incubation. s1-AII (24 h) increased the relative abundance of TH and PNMT mRNAs, suggesting that the long term increase in enzyme activities reflected increased expression of TH and PNMT genes. Maximal increases were observed at 2 nM s1-AII and the changes were antagonized by saralasin. Induction of TH mRNA by s1-AII was additive to the effects of veratridine or forskolin indicating that effects of angiotensin were not due to membrane depolarization or increased cyclic AMP levels. Incubation with Ca2+ ionophore A23187 increased TH and PNMT mRNA levels in AM cells raising the possibility that the increase in cellular [Ca2+] could mediate effects of angiotensin. Angiotensin-induced increases in TH and PNMT mRNA were inhibited by nifedipine indicating involvement of voltage-dependent Ca2+ channels. In addition, the increases in TH, but not PNMT mRNA, were antagonized by dantrolene, which inhibits mobilization of Ca2+ from intracellular stores. Calmodulin involvement was suggested by the inhibition of s1-AII induced changes in mRNA with 1 microM calmidazolium.(ABSTRACT TRUNCATED AT 400 WORDS)     

Weaning and the histology of the mandibular condyle in the rat.

Eighty-eight Long Evans/Turku rats were used in the study. The effect of the articulatory function on the mandibular condyle was observed histologically during normal growth, when the rat is changing its diet from milk to whole pellets as a part of weaning. Six animals each were killed at the age of 10, 15, 20, 25, 30, 35, 40 and 50 days for histological tissue processing. For further information, 30 animals were fed a soft diet (6 animals each were killed at the age of 25, 30, 35, 40 and 50 days), and 10 animals were fed hardened pellets (2 animals each were killed at the ages of 25, 30, 35, 40 and 50 days). An even and regular transition from mesenchymal cells via immature chondroblasts into mature chondroblasts and hypertrophied chondrocytes was found at 10, 15 and 20 days during normal growth and also at 25, 30, 35, 40 and 50 days when animals were fed a soft diet. This maturing process appeared to be disturbed at the age of 25, 30, 35 and 40 days in the superior aspect of the condyle in animals fed ordinary pellets. The density of the mesenchymal cell layer was decreased, and the amount of intercellular matrix seemed to be evaluated in mesenchymal and intermediate cell layers. These features were later manifest deeper in the cartilage as acellular regions and as cell clusters. The changes were similar but more severe when the animals were fed hardened pellets.(ABSTRACT TRUNCATED AT 250 WORDS)