Zofia E. Gagnon

Impact of platinum group metals on the environment: a toxicological, genotoxic and analytical chemistry study.

Recent studies show particles of Platinum Group Metals (PGMs); primarily platinum, palladium and rhodium; released from automobile catalytic converters are being deposited alongside roadways. This deposition is leading to increasing concentrations of PGMs in the environment, raising concerns about the environmental impact and toxicity of these elements in living organisms. The objective of this study was to determine how PGMs alter the patterns of growth, development, and physiology by studying the toxicological and genotoxic effects of these metals. Two vastly different species were used as models: plant—a wild wetland common Sphagnum moss, and animal—6-week old rats Sprague–Dawley. Both species were exposed, in controlled environments, to different concentrations of the PGMs. Toxicological and genotoxic effects were determined by assessment of plant growth, animal survival and pathology, and influence on DNA in both models. Our results on the uptake of PGMs by Sphagnum showed significant decreases in plant length and biomass as PGM concentration increased. Histological and pathological analysis of the animal model revealed vacuolization, eosinophil inclusion bodies in adrenal glands, shrinkage of glomeruli in the kidney, and enlargement of white pulp in the spleen. In both models, DNA damage was detected. Chemical analysis using ICP-AES atomic absorption demonstrated accumulation of PGMs in plant tissues at all PGM levels, proportional to concentration.

Induction of metallothionein in chick embryos as a mechanism of tolerance to platinum group metal exposure

Recent data show that platinum group metals (PGMs), primarily platinum (Pt), palladium (Pd) and rhodium (Rd), from automobile catalytic converters are being deposited in the environment. We investigated the PGM neurotoxicity and tolerance mechanism by induction of metallothionein (MT) in developing chick embryos. Chick embryos were injected on the 7th and 14th days of incubation with different concentrations of Pt and mixture of Pt, Pd and Rh (PGM mix) solutions. It is documented that induction of MT by zinc (Zn+2) protects against metal and non-metal hepatotoxicity. In this study the MT induction was examined through pretreatment of the two highest Pt(IV) exposure levels with exogenous Zn2+ on the 4th and 11th days of incubation. SDS-PAGE assay and digital image system were used to identify and quantify MT in homogenized brain and liver tissues. Quantitative analysis revealed an increase of MT in the 5 ppm Pt exposure as compared to controls. The 10 ppm Pt treatment was a lethal dose for exposed embryos. There was increased mortality at the 1.0 PGM mix level. The interaction of Pt, Pd and Rh in the mixture seems to favor metal accumulation and MT induction in the liver but not the brain. Pretreatment with exogenous Zn2+ increased chick survival. These results indicate that induction of MT plays a protective role against PGM toxicity. Metal analysis using atomic absorption spectrometer in graphite furnace mode (GFAAS) revealed PGM accumulation in chick embryo liver and brain tissues proportional to exposure concentration. Our results may imply that MT has an important role as a tolerance mechanism against PGM toxicity. The presence of Pt(IV) in brain tissue suggests that the undeveloped blood-brain barrier is permeable to PGMs. This raises concerns regarding the implication of these metals on neural injury.

Evaluating the abnormal ossification in tibiotarsi of developing chick embryos exposed to 1.0 ppm doses of platinum group metals by spectroscopic techniques

Platinum group metals (PGMs), i.e., palladium (Pd), platinum (Pt) and rhodium (Rh), are found at pollutant levels in the environment and are known to accumulate in plant and animal tissues. However, little is known about PGM toxicity. Our previous studies showed that chick embryos exposed to PGM concentrations of 1mL of 5.0ppm (LD50) and higher exhibited severe skeletal deformities. This work hypothesized that 1.0ppm doses of PGMs will negatively impact the mineralization process in tibiotarsi. One milliliter of 1.0ppm of Pd(II), Pt(IV), Rh(III) aqueous salt solutions and a PGM-mixture were injected into the air sac on the 7th and 14th day of incubation. Control groups with no-injection and vehicle injections were included. On the 20th day, embryos were sacrificed to analyze the PGM effects on tibiotarsi using four spectroscopic techniques. 1) Micro-Raman imaging: Hyperspectral Raman data were collected on paraffin embedded cross-sections of tibiotarsi, and processed using in-house-written MATLAB codes. Micro-Raman univariate images that were created from the ν1(PO4(3-)) integrated areas revealed anomalous mineral inclusions within the bone marrow for the PGM-mixture treatment. The age of the mineral crystals (ν(CO3(2-))/ν1(PO4(3-))) was statistically lower for all treatments when compared to controls (p≤0.05). 2) FAAS: The percent calcium content of the chemically digested tibiotarsi in the Pd and Pt groups changed by ~45% with respect to the no-injection control (16.1±0.2%). 3) Micro-XRF imaging: Abnormal calcium and phosphorus inclusions were found within the inner longitudinal sections of tibiotarsi for the PGM-mixture treatment. A clear increase in the mineral content was observed for the outer sections of the Pd treatment. 4) ICP-OES: PGM concentrations in tibiotarsi were undetectable (<5ppb). The spectroscopic techniques gave corroborating results, confirmed the hypothesis, and explained the observed pathological (skeletal developmental abnormalities) and histological changes (tibiotarsus ischemia and nuclear fragmentation in chondrocytes).

Teratogenic Effect of Broad-Band Electromagnetic Field on Neonatal Mice (Mus musculus)

Abstract Pregnant mice (Mus musculus), strain Swiss Webster, were exposed to a continuous electromagnetic field (12.8V/m) beginning in the third week of pregnancy. Histological and hematological analysis showed gender specific responses in 21 day-old mice after in-utero and post-natal continuous exposure. Automated lymphocyte percentage and total white blood cell counts were significantly elevated in exposed 21 day-old female mice compared to control mice. Lymphoma-like cells were seen in higher numbers in exposed 21 day-old male mice. Megaloblastic changes, such as hypersegmented neutrophils, were observed in exposed mice. The blood from control neonatal mice was more viscous than that of exposed mice, enough to interfere with making a blood smear. The adult female mice showed no significant differences in the above hematologic parameters between exposed and control groups. Histological study showed the following pathological changes in the adrenal cortex: degeneration/necrosis in the zona glomerulosa; hypertrophy in zona reticularis; degeneration/necrosis, intracytoplasmic inclusions and inflammation in the zona fasciculata/reticularis, more prominent in exposed female neonates; and lipidosis in the zona fasciculata. In the adrenal medulla: atrophy was more common in exposed female neonates; and intracytoplasmic inclusions and vacuolation were more common in exposed male neonates. Cystic proliferations were found in the cortical area of the thymus. In the medulla of the thymus, there was vacuolation, inflammation, or eosinophilic intracytoplasmic inclusions in exposed adults. Behavioral differences occurred in both neonates and adult females. Control neonates were able to manipulate through a maze more quickly than exposed neonates; and control adult females displayed more thorough grooming behavior than exposed mothers, and maintained more distance between the nest and dropping location than did the exposed group.

Comparative study of hematological responses to platinum group metals, antimony and silver nanoparticles in animal models

Research was conducted to examine the hematological effects of heavy metals (platinum (Pt (IV)), palladium (Pd (II)), rhodium (Rh (III)), antimony (Sb (III) and Sb (V)), and silver nanoparticles (AgNPs)) on white blood cells in mammalian (rat) and avian (chick embryo) models. These metals are used in many everyday products and are accumulating in our environment. Six—week old Sprague—Dawley female rats were treated daily by gavage and six—day old, fertile, specific pathogen—free white leghorn strain chick embryos’ eggs were injected on days 7 and 14 of incubation with 0.0, 1.0, 5.0 or 10.0 ppm concentrations of Pt (IV) and a platinum group metal (PGM) mix of Pt (IV), Pd (II) and Rh (III). Chick embryos were also tested with 1.0 or 5.0 ppm of antimony compounds (Sb (III) and Sb (V)) and 0.0, 15.0, 30.0, 60.0, or 100.0 ppm of silver nanoparticles (AgNPs). After 8 weeks of treatment, blood was obtained from the rats by jugular cut down and from chick embryos on day 20 of incubation by heart puncture. Blood smears were made and stained and a differential white cell count was performed on each. Examination of the smears revealed unconventional dose responses, stimulation of the immune response, and decreases in leukocyte production with various metals and concentrations. Chick embryos responded differently than rats to Pt and the PGM mix; suggesting that species differences and/or stage of development are important components of response to heavy metals. Route of administration of the metals might also influence the response. All of the heavy metals tested affected the immune responses of the tested animals as demonstrated by changes in the types and numbers of leukocytes. Our findings warrant further research to determine the mechanism of these effects and to understand and prevent toxicological effects in humans and other living organisms.

A histopathological study of Hudson River crayfish, Orconectes virilis, exposed to platinum group metals

Platinum group metals (PGMs), such as platinum (Pt), palladium (Pd), and rhodium (Rh), are of increasing concern due to rising anthropogenic input to aquatic systems. In this study, PGMs’ effects on bioaccumulation and histopathological changes were investigated using Orconectes virilis, a native Hudson River crayfish, as a model. Organisms were exposed to varying concentrations of water-soluble PGM salts for 10 days. The following experimental treatments were established: 0.0, 1.0, 5.0, 10.0 ppm Pt(IV), 1.0 ppm Rh(III), 1.0 ppm Pd(II), and a PGM mix (1.0 ppm Pt(IV), Rh(III), Pd(II) each) dissolved in raw Hudson River water. Metal content in the tissue samples were analyzed by a Spectro Genesis ICP-OES. The relationship between Pt, Pd, and Rh concentrations in different treatments and observed behavioral changes during the experiment was analyzed through One-Way ANOVA Student-Newman-Keuls multiple comparison test (P ≤ 0.05). Paraffin sections, 6-μm-thick, were prepared in standard eosin-Y and hematoxylin-2 stain and examined for histological abnormalities within hepatopancreas, exoskeleton, brain, and ganglia tissue. Statistically significant differences in PGM bioaccumulation were observed in all organs, with highest concentrations found in the hepatopancreas, 81.68 mg g−1 dw in 1.0 ppm Pd treatment, 20.03 mg g−1 dw Rh in 1.0 ppm Rh treatment, and 81.58 mg g−1 dw Pt in the 5.0 ppm Pt treatment. Pt bioaccumulation in the hepatopancreas and exoskeleton decreased at the highest Pt exposure treatment, suggesting severe structural damage to tissue. Hyper-segmentation of vacuoles and swelling of the vascular channels were observed in the hepatocyte structure of the hepatopancreas. Exoskeleton exhibited visible bands in the exocuticle indicating demineralization. Brain and ganglia demonstrated extensive vacuolization. Behavioral analysis showed an increase of maximum response intensity over the experimental period within each treatment. Bioaccumulation and cellular abnormalities observed in exposed aquatic organisms raise concern of PGM bio-magnification within the food chain and its effect on the environment and human health.

Freshwater Crayfish: A Potential Benthic-Zone Indicator of Nanosilver and Ionic Silver Pollution

Nowadays, silver nanoparticles (AgNPs) are utilized in numerous applications, raising justified concerns about their release into the environment. This study demonstrates the potential to use freshwater crayfish as a benthic-zone indicator of nanosilver and ionic silver pollution. Crayfish were acclimated to 20 L aquaria filled with Hudson River water (HRW) and exposed for 14 days to widely used Creighton AgNPs and Ag(+) at doses of up to 360 μg L(-1) to surpass regulated water concentrations. The uptake and distribution of Ag in over 650 exoskeletons, gills, hepatopancreas and muscles samples were determined by inductively coupled plasma optical emission spectroscopy (ICP-OES) in conjunction with two complementary U.S. EPA-endorsed methods: the external calibration and the standard additions. Reflecting the environmental plasticity of the two investigated species, Orconectes virilis accumulated in a dose-dependent manner more Ag than Procambarus clarkii (on average 31% more Ag). Both species showed DNA damage and severe histological changes in the presence of Ag. However, Ag(+) generally led to higher Ag accumulations (28%) and was more toxic. By the harvest day, about 14 ± 9% of the 360 μg L(-1) of AgNP exposure in the HRW oxidized to Ag(+) and may have contributed to the observed toxicities and bioaccumulations. The hepatopancreas (1.5-17.4 μg of Ag g(-1) of tissue) was identified as the best tissue-indicator of AgNP pollution, while the gills (4.5-22.0 μg g(-1)) and hepatopancreas (2.5-16.7 μg g(-1)) complementarily monitored the presence of Ag(+).

Distance running alters peripheral microRNAs implicated in metabolism, fluid balance, and myosin regulation in a sex-specific manner

Microribonucleic acids (miRNAs) mediate adaptive responses to exercise and may serve as biomarkers of exercise intensity/capacity. Expression of miRNAs is altered in skeletal muscle, plasma, and saliva following exertion. Women display unique physiologic responses to endurance exercise, and miRNAs respond to pathologic states in sex-specific patterns. However sex-specific miRNA responses to exercise remain unexplored. This study utilized high-throughput RNA sequencing to measure changes in salivary RNA expression among 25 collegiate runners following a single long-distance run. RNA concentrations in pre- and post-run saliva was assessed through alignment and quantification of 4,694 miRNAs and 27,687 mRNAs. Pair-wise Wilcoxon rank-sum test identified miRNAs with significant [false discovery rate (FDR) < 0.05] post-run changes. Associations between miRNA levels and predicted mRNA targets were explored with Pearson correlations. Differences in miRNA patterns between men ( n = 13) and women ( n = 12) were investigated with two-way analysis of variance. Results revealed 122 salivary miRNAs with post-run changes. The eight miRNAs with the largest changes were miR-3671, miR-5095 (downregulated); and miR-7154-3p, miR-200b-5p, miR-5582-3p, miR-6859-3p, miR-6751-5p, miR-4419a (upregulated). Predicted mRNA targets for these miRNAs represented 15 physiologic processes, including glycerophospholipid metabolism (FDR = 0.042), aldosterone-regulated sodium reabsorption (FDR = 0.049), and arrhythmogenic ventricular cardiomyopathy (FDR = 0.018). Twenty-six miRNA/mRNA pairs had associated changes in post-run levels. Three miRNAs (miR-4675, miR-6745, miR-6746-3p) demonstrated sex-specific responses to exercise. Numerous salivary miRNAs change in response to endurance running and target the expression of genes involved in metabolism, fluid balance, and musculoskeletal adaptations. A subset of miRNAs may differentiate the metabolic response to exercise in men and women.

The effects of broad‐band electromagnetic field exposure on mice (Mus musculus)

Abstract Mice (Mus musculus), strain Swiss Webster, were exposed to an electromagnetic field (12.8 V/m) continuously for a period of eight weeks. Blood smear for differentials (lymphocytes, neutrophils, eosinophils, monocytes, stabs, and nucleated red blood cells) and tissue samples of the target organs (the thymus and adrenal glands) were analyzed for signs of stress from the electromagnetic field (EMF). Hematology analysis showed that the immune response is gender specific. Females suppressed the neutrophils while males suppressed the lymphocytes when exposed to the EMF. Histology analysis showed that there were gender differences with regards to the lesions in the thymus and adrenal glands. Females were adrenal sensitive, while males were thymus sensitive.

Does methadone exposure during avian development alter sex ratio of survivors

Aim: Methadone is commonly used to treat pregnant heroin users and presumed to be safe for developing offspring. An avian model, free of confounding maternal variables, was used to investigate sex differences from methadone exposure during development. Place and Duration of Study: Studies were conducted at Marist College, Poughkeepsie, NY between June 2012 and May 2013. Methodology: In the first experiment, methadone in phosphate buffered saline was administered to fertilized eggs at one of two doses (0.458 mg/kg or 1.75 mg/kg) for one of three durations of exposure (Late, Incubation Days 12 to 19; Mid to Late, Days 9 to 19; or Early to Late, Days 5 to 19) with six eggs in each dose x duration condition and six controls (N = 42 eggs). Feathers were taken from eggs with developed embryos from this study for DNA analysis. DNA analysis was not attempted on embryos that had died early in development and decomposed before eggs were opened on Day 20. In a second experiment, methadone (1.00 mg/kg) was administered to eggs from which embryos were sacrificed at four time points during development to investigate growth Original Research Article Dingman et al.; BJMMR, 6(3): 254-264, 2015; Article no.BJMMR.2015.201 255 retardation in methadone exposed embryos as compared with controls. Feathers were taken from randomly selected eggs exposed from Day 8 to Day 19 for sexing (N = 10 exposed and N = 10 controls. Results: Methadone exposure significantly affected embryo viability. The sex ratio of exposed specimens was 2:1 in favor of females, a departure from the normal 1:1 ratio. The results suggest that most of the embryos that died during incubation were male. Conclusion: The skewed sex ratio observed in this study suggests a sex difference in mortality from methadone exposure during development.