Genotoxicity testing for radon exposure： Dolichopoda （Orthoptera,Rhaphidophoridae） as potential bio-indicator of confined environments

Radon represents the major source of natural radioactivity in confined environments. Despite the clear evidence of a direct association between residential exposure and human lung cancer provided by case-control studies, results relating indoor exposure and genotoxic/mutagenic effect induction are still contradictory. The present study attempts to estimate the genotoxic effects induced by exposure to radioactive radon in wild cricket populations sampled from caves where varying concentrations of radon are present. Cave crickets are also tested as possible bio-indicator organisms of genotoxic potential of contaminated residential and confined environments. Six caves in Central Italy are considered covering a broad spectrum of radon radioactivity concentration （221-26,000 Bq/m3）. Dolichopoda specimens were sampled from each cave; both haemocytes and brain cells taken from individuals were tested for responsiveness to DNA damage induced by radon through the Comet assay. Specimens from the least radioactive cave, housed in controlled conditions for 60 days before analysis, were used as control group. Statistically significant increase of DNA damage was found in all groups of individuals from each cave, for both cell types. Very low values of all Comet parameters were found in control group individuals, which gave indications of a good responsiveness of the organism to the variable environmental levels of radioactive contamination. Results indicate that cave crickets represent a reliable tool for the detection of genotoxic potential induced by radioactive contamination of confined environments and can be proposed as a possible bio-indicator system for air （-radioactive） pollution related to indoor exposure [Current Zoology 60 （2）： 299-307, 2014].     

PHYSIOLOGICAL SNAPSHOTS REFLECT ECOLOGICAL PERFORMANCE OF THE SEA PALM,POSTELSIA PALMAEFORMIS (PHAEOPHYCAEA) ACROSS INTERTIDAL ELEVATION AND EXPOSURE GRADIENTS1

Postelsia palmaeformis Ruprecht is an intertidal kelp found only on very wave‐exposed rocky shores of the northeast Pacific. In areas dominated by mussels, Postelsia depends on wave‐induced disturbances to complete its life‐history cycle. Postelsia also recruits where mussels are absent, but not at less wave‐exposed shores. Thus, physical conditions related to wave exposure limit its horizontal distribution. It is not clear what limits the vertical distribution of Postelsia. We investigated factors contributing to Postelsia's limited distribution using transplant experiments, demographic monitoring, and field fluorometry to evaluate growth and performance across gradients of tidal elevation and wave exposure. Survivorship and growth were sharply reduced at upper and wave‐protected edges relative to mid‐level, wave‐exposed sporophytes. Reproductive output was reduced at upper and lower levels, and growth but not survivorship was lower at the lower level. Effects were independent of population of origin and were a manifestation of the environment. Maximum electron transport rates (ETR_m), light saturation parameters (E_k), and maximum quantum yields (ΔF/F_m) provided insight into physiological dynamics; all were lowest at the high edge, but increased when desiccation stress was alleviated by a mock sea‐spray treatment. The ETR_m and E_k values of low sporophytes were not as high as the values for mid‐sporophytes, despite higher or equivalent nitrogen content, chl a, and absorptance, suggesting a trade‐off between light‐capturing and carbon‐fixation capacity. Physiological limitations at upper and lower levels and deleterious desiccation effects at wave‐protected sites prevent establishment, thus constraining Postelsia to a mid‐zone, wave‐exposed distribution. Physical conditions related to wave exposure may limit the horizontal distribution of Postelsia because this kelp is also found in areas where mussels are lacking but not on less wave‐exposed shores.     

热暴露大鼠心肌细胞钙稳态及其调节机制的研究

本文观察了离体成年大鼠心室肌肌质网、线粒体Ｃａ＾２＋－ＡＴＰ酶活性和总钙含是到及原代培养乳腺心肌细胞＾４６Ｃａ摄取、活性钙调素相对含量、胞浆内游离钙浓度在不同温度热暴露４０ｍｉｎ后的变化。结果表明：热暴露后,心肌奖浆、肌质网及线粒体中的Ｃａ＾２＋－ＡＴＰ酶活发表 所下降,心肌肌质网及线粒体中的总钙含量亦有降低趋势,心肌细胞活性钙调素相对含量显著下降,＾４６Ｃａ摄取量及胞浆内游离浓度显著升高。提示,     

Prediction of herbage yield in grassland: How well do Ellenberg N‐values perform?

Question: How useful are Ellenberg N‐values for predicting the herbage yield of Central European grasslands in comparison to approaches based on ordination scores of plant species composition or on soil parameters? Location: Central Germany (11°00′‐11°37’E, 50°21‐50°34’N, 500–840 m a.s.l.). Methods: Based on data from a field survey in 2001, the following models were constructed for predicting herbage yield in montane Central European grasslands: (1) Linear regression of mean Ellenberg N‐, R‐ and F‐values; (2) Linear regression of ordination scores derived from Non‐metric Multidimensional Scaling (NMDS) of vegetation data; and (3) Multiple linear regression (MLR) of soil variables. Models were evaluated by cross‐validation and validation with additional data collected in 2002. Results: Best predictions were obtained with models based on species composition. Ellenberg N‐values and NMDS scores performed equally well and better than models based on Ellenberg R‐ or F‐values. Predictions based on soil variables were least accurate. When tested with data from 2002, models based on Ellenberg N‐values or on NMDS scores accurately predicted productivity rank order of sites, but not the actual herbage yield of particular sites. Conclusions: Mean Ellenberg N‐values, which are easy to calculate, are as accurate as ordination scores in predicting herbage yield from plant species composition. In contrast, models based on soil variables may be useful for generating hypotheses about the factors limiting herbage yield, but not for prediction. We support the view that Ellenberg N‐values should be called productivity values rather than nitrogen values.     

A neutron activation technique for manganese measurements in humans

Manganese (Mn) is an essential element for humans, animals, and plants and is required for growth, development, and maintenance of health. Studies show that Mn metabolism is similar to that of iron, therefore, increased Mn levels in humans could interfere with the absorption of dietary iron leading to anemia. Also, excess exposure to Mn dust, leads to nervous system disorders similar to Parkinson's disease. Higher exposure to Mn is essentially related to industrial pollution. Thus, there is a benefit in developing a clean non-invasive technique for monitoring such increased levels of Mn in order to understand the risk of disease and development of appropriate treatments.To this end, the feasibility of Mn measurements with their minimum detection limits (MDL) has been reported earlier from the McMaster group. This work presents improvement to Mn assessment using an upgraded system and optimized times of irradiation and counting for induced gamma activity of Mn. The technique utilizes the high proton current Tandetron accelerator producing neutrons via the ⁷Li(p,n)⁷Be reaction at McMaster University and an array of nine NaI (Tl) detectors in a 4π geometry for delayed counting of gamma rays. The neutron irradiation of a set of phantoms was performed with protocols having different proton energy, current and time of irradiation. The improved MDLs estimated using the upgraded set up and constrained timings are reported as 0.67 μgMn/gCa for 2.3 MeV protons and 0.71 μgMn/gCa for 2.0 MeV protons. These are a factor of about 2.3 times better than previous measurements done at McMaster University using the in vivo set-up. Also, because of lower dose-equivalent and a relatively close MDL, the combination of: 2.0 MeV; 300 μA; 3 min protocol is recommended as compared to 2.3 MeV; 400 μA; 45 s protocol for further measurements of Mn in vivo.     

Critical Role of Lipid Scramblase TMEM16F in Phosphatidylserine Exposure and Repair of Plasma Membrane after Pore Formation

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The association between exposure determined by radiofrequency personal exposimeters and human exposure: A simulation study

The selection of an adequate exposure assessment approach is imperative for the quality of epidemiological studies. The use of personal exposimeters turned out to be a reasonable approach to determine exposure profiles, however, certain limitations regarding the absolute values delivered by the devices have to be considered. Apart from the limited dynamic range, it has to be taken into account that these devices give only an approximation of the exposure due to the influence of the body of the person carrying the exposimeter, the receiver characteristics of the exposimeter, as well as the dependence of the measured value on frequency band, channel, slot configuration, and communication traffic. In this study, the relationship between the field strength measured close to the human body at the location of the exposimeter and the exposure, that is, the field strength at the location of the human body without the human body present, is investigated by numerical means using the Visible Human model as an anatomical phantom. Two different scenarios were chosen: (1) For FM, GSM, and UMTS an urban outdoor scenario was examined that included a transmitting antenna mounted on the roof of one of four buildings at a street crossing, (2) For WLAN an indoor scenario was investigated. For GSM the average degree of underestimation by the exposimeter (relation of the average field levels at the location of the exposimeter to the field level averaged over the volume of the human body without the body present) was 0.76, and for UMTS 0.87; for FM no underestimation was found, the ratio was 1. In the case of WLAN the degree of underestimation was more pronounced, the ratio was 0.64. This study clearly suggests that a careful evaluation of correction factors for different scenarios is needed prior to the definition of the study protocol. It has to be noted that the reference scenario used in this study does not allow for final conclusions on general correction factors. Bioelectromagnetics 31:535–545, 2010. © 2010 Wiley‐Liss, Inc.     

Effects of a long-term exposure with OTA or OTC on functions of a human monocytic cell line

An in-vitro model was developed to study the effects of a long-term exposure with a low concentration of ochratoxin A (OTA) or ochratoxin C (OTC) on a human monocytic cell line (THP-1). Cells were propagated in 24-well cell culture plates for 15 days. OTA and OTC preparations, respectively, at a concentration of 1 ng/ml were included in the cell culture medium during the whole cultivation period. At the end of the exposure time, parameters of cell viability and cell function were examined. After 15 days of exposure to ochratoxins, viability and function of the THP-1 cell line were modulated. Mitochondrial activity and the production of IL-6 were increased by all mycotoxin preparations. Cell membrane integrity was disturbed, proliferation and the production of TNF-α and IL-8 were inhibited. These parameters were most severely affected by mycotoxin preparations containing OTC. Our results show that long term exposure to OTA and especially OTC in low concentrations can cause subtle alterations of cell viability and function which may have remarkable consequences for human and animal health. In this context it seems to be necessary to study the contamination of food and feed stuffs with OTC more intensively. Presented at the 25^th Mykotoxin Workshop in Giessen, Germany, May 19–21, 2003     

Exposure reconstruction for reducing uncertainty in risk assessment: example using MTBE biomarkers and a simple pharmacokinetic model

Adverse health risks from environmental agents are generally related to average (long-term) exposures. Because a given individual's contact with a pollutant is highly variable and dependent on activity patterns, local sources and exposure pathways, simple 'snapshot' measurements of surrounding environmental media may not accurately assign the exposure level. Furthermore, susceptibility to adverse effects from contaminants is considered highly variable in the population so that even similar environmental exposure levels may result in differential health outcomes in different individuals. The use of biomarker measurements coupled to knowledge of rates of uptake, metabolism and elimination has been suggested as a remedy for reducing this type of uncertainty. To demonstrate the utility of such an approach, we invoke results from a series of controlled human exposure tests and classical first-order rate kinetic calculations to estimate how well spot measurements of methyl tertiary butyl ether and the primary metabolite, tertiary butyl alcohol, can be expected to predict different hypothetical scenarios of previous exposures. We found that blood and breath biomarker measurements give similar results and that the biological damping effect of the metabolite production gives more stable estimates of previous exposure. We also explore the value of a potential urinary biomarker, 2-hydroxyisobutyrate suggested in the literature. We find that individual biomarker measurements are a valuable tool in reconstruction of previous exposures and that a simple pharmacokinetic model can identify the time frames over which an exogenous chemical and the related chemical biomarker are useful. These techniques could be applied to broader ranges of environmental contaminants to assess cumulative exposure risks if ADME (Absorption, Distribution, Metabolization and Excretion) is understood and systemic biomarkers can be measured.     

Intermittent cold-induced hippocampal oxidative stress is associated with changes in the plasma lipid composition and is modifiable by vitamins C and E in old rats

This study primarily investigated the effects of intermittent cold exposure (ICE) on oxidative stress (OS) in the hippocampus(HC) and plasma lipid profile of old male rats. Secondly, it evaluated structural changes in the hippocampus region of the rat’s brain. Thirdly, it attempted an evaluation of the effectiveness of the combined supplement of vitamins C and E in alleviating cold stress in terms of these biochemical parameters. Thirty male rats aged 24 months were divided into groups of five each: control (CON), cold-exposed at 10 °C (C10), cold-exposed at 5 °C (C5), supplemented control (CON+S), and supplemented cold-exposed at either 5 °C (C5+S) or 10 °C (C10+S). The rats were on a daily supplement of vitamin C and vitamin E. Cold exposure lasted 2 h/day for 4 weeks. Rats showed increased levels of hydrogen peroxide (H₂O₂), and thiobarbituric acid reactive substances (TBARS) in the HC at 10 °C with further increase at 5 °C. Cold also induced neuronal loss in the hippocampus with concomitant elevations in total cholesterol (TCH), triglycerides (TG) and low-density lipoproteins (LDL-C) levels, and a depletion in high-density lipoprotein (HDL-C). A notable feature was the hyperglycaemic effects of ICE and depleted levels of vitamins C and E in the hippocampus and plasma while supplementation increased their levels. More importantly, a positive correlation was observed between plasmatic LDL-C, TCH and TG and hippocampal TBARS and H₂O₂ levels. Further, intensity of cold emerged as a significant factor impacting the responses to vitamin C and E supplementation. These results suggest that cold-induced changes in the plasma lipid profile correlate with OS in the hippocampus, and that vitamin C and E together are effective in protecting from metabolic and possible cognitive consequences in the old under cold exposures.