Are Seafood PCB Data Sufficient to Assess Health Risk for High Seafood Consumption Groups?

Some populations in Washington's Puget Sound area consume much more seafood than the general population. Mean consumption rates are 61?g/person/day for the Tulalip and Squaxin Island Tribes and 117.2?g/person/day for Asian and Pacific Islanders (API). There is concern about possible health risks from seafood PCB exposure for these groups, but exposure evaluation is difficult due to inadequacies of environmental data. Available seafood PCB data were matched to results from recent seafood consumption surveys. To rate quality of matches and identify data gaps, a ranking system based on species specificity, data quality, and location compatibility was developed. Sensitivity of total PCB and congenerspecific PCB testing (for use in TCDD toxic equivalency approaches) necessary for cancer risk assessment was explored and included in the ranking scheme. For the Squaxin Tribe, appropriate total PCB data for risk assessment were available for 58% of seafood consumed, which is dominated by local salmon. For API, appropriate total PCB data were identified for only 4% of seafood consumed, which is dominated by commercial shellfish. Insufficient sensitivity of commercial seafood PCB analysis and overall lack of sufficiently sensitive PCB congener analysis are major gaps in ability to characterize PCB exposure and risk for these groups.     

Characterization and Mapping of Contaminated Sediments,Windermere Arm,Hamilton Harbour,Ontario, Canada

Windermere Arm is a 50-ha narrow channel located in the south-eastern portion of Hamilton Harbour, which is designated by the International Joint Commission (IJC) as one of the primary Areas of Concern in the Canadian waters of the Great Lakes. Sediments within the Arm have historically been contaminated with metals, PAHs, and to a lesser extent, PCBs. Sedimentological, geotechnical and geochemical investigations have been undertaken to determine the degree and the spatial extent of contamination. The thickness of contaminated sediment and their degree of contamination vary widely within the study site. Information on the thickness of contamination obtained from logging and chemical analysis of sediment cores agrees in general with the results of in situ penetrometer testing. Concentrations of Zn and Pb in some sub-samples are above the Severe Effect Level (SEL) for benthos set by the Ontario sediment quality guidelines. On average, surficial sediments tend to have lower metal concentrations than deeper sediments, probably due to the reduction of industrial point discharges. Apart from the two main boat slips, concentrations of PAHs are relatively low and in agreement with previously reported values. In contrast, new results yield higher values of PCB concentrations than previously reported, and 21 sub-samples of surficial sediment analyzed yielded values greater than 1 μg/g. Results suggest that the majority of recent PCB loadings are entering the study site from nearshore industrial spills or dumping, despite the detection of trace amounts of PCBs in a nearby creek. Pronounced sediment disturbance noted in several cores suggests that more contaminated historical sediments are at risk of being disturbed and re-exposed to the water column.     

Effects of Cadmium and Mixed Heavy Metals on Rice Growth in Liaoning,China

Joint effects of Cd and other heavy metals (Pb, Cu, Zn and As) on the growth and development of rice plants and the uptake of these heavy metals by rice were studied using the pot-culture method combined with chemical and statistical analyses. The results showed that the growth and development of rice plants were strongly influenced by the double-element combined pollution. There was an average decrease in the height of rice plants of 4.0–5.0 cm, and grain yield was decreased by 20.0–30.0%, compared with the control. The uptake of Cd by rice plants was promoted due to the interactions between Cd and the other heavy metals added to the soil. The Cd concentration in roots, stems/leaves and seeds increased 31.6–47.7, 16.7–61.5 and 19.6–78.6%, respectively. Due to interactions, uptake of Pb, Cu and Zn by roots and stems/leaves was inhibited, accumulation of Pb, Cu and Zn in seeds was increased, uptake of As by roots was promoted and uptake of As by stems/leaves was inhibited. In particular, the upward transporting ability of the heavy metals absorbed by rice plants was significantly increased.     

复方醋酸棉酚片联合独一味胶囊对大鼠无排卵型功能失调性子宫出血的改善作用及其作用机制

摘要 目的：探讨复方醋酸棉酚片联合独一味胶囊对大鼠无排卵型功能失调性子宫出血的改善作用及其作用机制。方法：将40只雌性SD大鼠随机均分成两组（空白组和模型组）,采用给大鼠连续21 d灌胃戊酸雌二醇的方法制备无排卵型功能失调性子宫大鼠模型。模型大鼠制备成功后,按随机法再均分成模型组、阳性组和治疗组,其中阳性组和治疗组分别灌胃给予相应的药物,空白组和模型组灌胃等体积的生理盐水,各组均连续灌胃7 d。计算各组大鼠的子宫系数,采用酶联免疫吸附法测定大鼠血清中雌二醇（estradiol, E₂）和孕酮（progestone,P）水平,采用免疫组化法测定大鼠子宫内膜组织中两个蛋白（matrix metalloproteinases-9,MMP-9和vascular endothelial growth factor ,VEGF）的表达量。结果：模型组大鼠血清中的P水平比空白组显著性减少（P<0.05）,子宫内膜组织中的MMP-9和VEGF表达量比空白组均显著性升高（P<0.05）。给药后,治疗组和阳性组大鼠血清中的P水平均显著高于模型组（P<0.05）,大鼠子宫内膜组织中的MMP-9和VEGF 表达量均显著低于模型组（P<0.05）,治疗组与阳性组之间无显著性差异（P >0.05）。结论：复方醋酸棉酚片联合独一味胶囊对无排卵型功能失调性子宫出血具有明显的改善作用,其机制可能与调控子宫内膜 MMP-9 和VEGF的表达量有关。     

丛枝菌根真菌与高羊茅协同修复镉污染土壤

本研究采用温室盆栽试验,利用丛枝菌根（AM）真菌摩西管柄囊霉Funneliformis mosseae进行接种试验,研究了在Cd胁迫下（0、5、15和30mg/kg）接种AM真菌对高羊茅Festuca elata ‘Crossfire II’的生物量、防御酶活性、磷和镉（Cd）含量的影响。结果表明,随着Cd浓度的增加,高羊茅的菌根侵染率和菌根相对依赖性有所增加。接种AM真菌改善了磷从植株根系向地上部的转运,有助于植株在地上部积累更多的磷。此外,AM真菌和Cd胁迫对高羊茅植株抗氧化酶活性都有显著影响,在镉胁迫下,与未接种植株相比,接种AM真菌显著提高了植株的过氧化氢酶活性,而显著降低了植株的丙二醛含量。与未接种植株相比,接种摩西管柄囊霉显著提高了寄主植物对Cd的富集能力,有利于重金属在根部的积累,同时降低了地上部的Cd含量。本研究表明,高羊茅-丛枝菌根共生体在Cd污染土壤的修复中具有潜在应用价值。     

In vitro Cell Culture Model for Toxic Inhaled Chemical Testing

Cell cultures are indispensable to develop and study efficacy of therapeutic agents, prior to their use in animal models. We have the unique ability to model well differentiated human airway epithelium and heart muscle cells. This could be an invaluable tool to study the deleterious effects of toxic inhaled chemicals, such as chlorine, that can normally interact with the cell surfaces, and form various byproducts upon reacting with water, and limiting their effects in submerged cultures. Our model using well differentiated human airway epithelial cell cultures at air-liqiuid interface circumvents this limitation as well as provides an opportunity to evaluate critical mechanisms of toxicity of potential poisonous inhaled chemicals. We describe enhanced loss of membrane integrity, caspase release and death upon toxic inhaled chemical such as chlorine exposure. In this article, we propose methods to model chlorine exposure in mammalian heart and airway epithelial cells in culture and simple tests to evaluate its effect on these cell types.     

Mechanisms of cohesin-mediated gene regulation and lessons learned from cohesinopathies

Cohesins are conserved and essential Structural Maintenance of Chromosomes (SMC) protein-containing complexes that physically interact with chromatin and modulate higher-order chromatin organization. Cohesins mediate sister chromatid cohesion and cellular long-distance chromatin interactions affecting genome maintenance and gene expression. Discoveries of mutations in cohesin's subunits and its regulator proteins in human developmental disorders, so-called “cohesinopathies,” reveal crucial roles for cohesins in development and cellular growth and differentiation. In this review, we discuss the latest findings concerning cohesin's functions in higher-order chromatin architecture organization and gene regulation and new insight gained from studies of cohesinopathies. This article is part of a Special Issue entitled: Chromatin and epigenetic regulation of animal development.     

Two combined photosensitizers: a goal for more effective photodynamic therapy of cancer

Photodynamic therapy (PDT) is a clinically approved therapeutic modality for the treatment of diseases characterized by uncontrolled cell proliferation, mainly cancer. It involves the selective uptake of a photosensitizer (PS) by neoplastic tissue, which is able to produce reactive oxygen species upon irradiation with light, leading to tumor regression. Here a synergistic cell photoinactivation is reported based on the simultaneous administration of two PSs, zinc(II)-phthalocyanine (ZnPc) and the cationic porphyrin meso-tetrakis(4-N-methylpyridyl)porphine (TMPyP) in three cell lines (HeLa, HaCaT and MCF-7), using very low doses of PDT. We detected changes from predominant apoptosis (without cell detachment) to predominant necrosis, depending on the light dose used (2.4 and 3.6 J/cm², respectively). Analysis of changes in cytoskeleton components (microtubules and F-actin), FAK protein, as well as time-lapse video microscopy evidenced that HeLa cells were induced to undergo apoptosis, without losing adhesion to the substrate. Moreover, 24 h after intravenous injection into tumor-bearing mice, ZnPc and TMPyP were preferentially accumulated in the tumor area. PDT with combined treatment produced significant retardation of tumor growth. We believe that this combined and highly efficient strategy (two PSs) may provide synergistic curative rates regarding conventional photodynamic treatments (with one PS alone).     

No evidence for induction or selection of mutant sodium channel expression in the copepod Acartia husdsonica challenged with the toxic dinoflagellate Alexandrium fundyense

Some species in the dinoflagellate genus Alexandrium spp. produce a suite of neurotoxins that block sodium channels, known as paralytic shellfish toxins (PST), which have deleterious effects on grazers. Populations of the ubiquitous copepod grazer Acartia hudsonica that have co‐occurred with toxic Alexandrium spp. are better adapted than naïve populations. The mechanism of adaptation is currently unknown. We hypothesized that a mutation in the sodium channel could account for the grazer adaptation. We tested two hypotheses: (1) Expression of the mutant sodium channel could be induced by exposure to toxic Alexandrium fundyense; (2) in the absence of induction, selection exerted by toxic A. fundyense would favor copepods that predominantly express the mutant isoform. In the copepod A. hudsonica, both isoforms are expressed in all individuals in varying proportions. Thus, in addition to comparing expression ratios of wild‐type to mutant isoforms for individual copepods, we also partitioned copepods into three groups: those that predominantly express the mutant (PMI) isoform, the wild‐type (PWI) isoform, or both isoforms approximately equally (EI). There were no differences in isoform expression between individuals that were fed toxic and nontoxic food after three and 6 days; induction of mutant isoform expression did not occur. Furthermore, the hypothesis that mutant isoform expression responds to toxic food was also rejected. That is, no consistent evidence showed that the wild‐type to mutant isoform ratios decreased, or that the relative proportion of PMI individuals increased, due to the consumption of toxic food over four generations. However, in the selected line that was continuously exposed to toxic food sources, egg production rate increased, which suggested that adaptation occurred but was unrelated to sodium channel isoform expression.     

Physiological description of multivariate interdependencies between process parameters,morphology and physiology during fed‐batch penicillin production

Optimization of productivity and economics of industrial bioprocesses requires characterization of interdependencies between process parameters and process performance. In the case of penicillin production, as in other processes, process performance is often closely interlinked with the physiology and morphology of the organism used for production. This study presents a systematic approach to efficiently characterize the physiological effects of multivariate interdependencies between bioprocess design parameters (spore inoculum concentration, pO₂ control level and substrate feed rate), morphology, and physiology. Method development and application was performed using the industrial model process of penicillin production. Applying traditional, statistical bioprocess analysis, multivariate correlations of raw bioprocess design parameters (high spore inoculum concentration, low pO₂ control as well as reduced glucose feeding) and pellet morphology were identified. A major drawback of raw design parameter correlation models; however, is the lack of transferability across different process scales and regimes. In this context, morphological and physiological bioprocess modeling based on scalable physiological parameters is introduced. In this study, raw parameter effects on pellet morphology were efficiently summarized by the physiological parameter of the biomass yield per substrate. Finally, for the first time to our knowledge, the specific growth rate per spore was described as time‐independent determinant for switching from pellet to disperse growth during penicillin production and thus introduced as a novel, scalable key process parameter for pellet morphology and process performance. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:689–699, 2014