Laboratory Exposure Research Articles

Limbic encephalitis in a neuroscientist: CASPR 2 antibody-associated disease after antigen exposure

Autoimmune limbic encephalitis is part of CASPR 2 antibody-associated disease. A man with this rare disorder and a very high antibody titre had a unique history of laboratory exposure to the antigen. Together with earlier observations this case calls for caution in laboratory handling of nerve tissue.

USB-powered physics experiments

Physics experiments powered by a universal serial bus (USB) connection are becoming increasingly common. With teachers going through so many batteries each year, USB-powered physics provides an economical and environmentally friendly alternative. In this article, the authors discuss several ways that USB power can provide a convenient way to do physics labs. USB power not only provides an alternative to batteries, but also hand-crank generators, power supplies, and even more exotic demonstration equipment such as Tesla coils. Cell phone chargers, including wireless chargers, are also investigated with these tools. The ubiquity of USB justifies that students receive at least some laboratory exposure to them and how they work.

Polystyrene microplastics do not affect juvenile brown trout (Salmo trutta f. fario) or modulate effects of the pesticide methiocarb

BackgroundThere has been a rising interest within the scientific community and the public about the environmental risk related to the abundance of microplastics in aquatic environments. Up to now, however, scientific knowledge in this context has been scarce and insufficient for a reliable risk assessment. To remedy this scarcity of data, we investigated possible adverse effects of polystyrene particles (104 particles/L) and the pesticide methiocarb (1 mg/L) in juvenile brown trout (Salmo trutta f. fario) both by themselves as well as in combination after a 96 h laboratory exposure. PS beads (density 1.05 g/mL) were cryogenically milled and fractionated resulting in irregular-shaped particles (< 50 µm). Besides body weight of the animals, biomarkers for proteotoxicity (stress protein family Hsp70), oxidative stress (superoxide dismutase, lipid peroxidation), and neurotoxicity (acetylcholinesterase, carboxylesterases) were analyzed. As an indicator of overall health, histopathological effects were studied in liver and gills of exposed fish.ResultsPolystyrene particles by themselves did not influence any of the investigated biomarkers. In contrast, the exposure to methiocarb led to a significant reduction of the activity of acetylcholinesterase and the two carboxylesterases. Moreover, the tissue integrity of liver and gills was impaired by the pesticide. Body weight, the oxidative stress and the stress protein levels were not influenced by methiocarb. Effects caused by co-exposure of polystyrene microplastics and methiocarb were the same as those caused by methiocarb alone.ConclusionsOverall, methiocarb led to negative effects in juvenile brown trout. In contrast, polystyrene microplastics in the tested concentration did not affect the health of juvenile brown trout and did not modulate the toxicity of methiocarb in this fish species.

Association between fine particle exposure and common test items in clinical laboratory: A time-series analysis in Changsha, China

Most studies on the health effects of PM2.5 (fine particulate matter with diameter smaller than 2.5 μm) use indirect indicators, such as mortality and number of hospital visits. Recent research shows that biomarkers can also be used to evaluate the health effects of PM2.5; however, these biomarkers are not very common. Clinical laboratories can provide a significant amount of test data that have been proven to have important diagnostic value. Therefore, we use big data analysis methods to find the associations between clinical laboratory common test items and PM2.5 exposure. Data related to air pollution and meteorological information between 2014 and 2016 were obtained from the China National Environmental Monitoring Centre and the China National Meteorological Information Center. Additionally, data of 27 common test items from the same period were collected from Changsha Central Hospital. Primary analyses included a generalized additive model to analyze the associations between PM2.5 concentration and common test items; the model was adjusted for time trends, weather conditions (temperature and humidity), and days of the week. Furthermore, we adjusted the effects of other air pollutants, such as PM10, SO2, NO2, CO, and O3. 17 items such as TP, ALB, ALT, AST, TBIL, DBIL, UREA, CREA, UA, GLU, LDL, WBC, K, Cl, Ca, TT, and FIB were significantly positively associated with PM2.5 concentration (P< 0.05) and have concentration-response relationship. After adjusting the effect of PM10+SO2+NO2+CO+O3, TP, ALB, ALT, AST, TBIL, DBIL, UREA, CREA, UA, GLU, WBC, Cl, and Ca were still significantly associated with PM2.5 concentration (P< 0.05). This current study suggested that clinical laboratory common test items may be used to assess and predict the health effects of PM2.5 on the population.

Polystyrene microplastics decrease accumulation of essential fatty acids in common freshwater algae

Despite growing concern about the occurrence of microplastics in aquatic ecosystems there is only rudimentary understanding of the pathways through which any adverse effects might occur. Here, we assess the effects of polystyrene microplastics (PS-MPs; <70 μm) on a common and widespread algal species, Chlorella sorokiniana. We used laboratory exposure to test the hypothesis that the lipids and fatty acids (FAs) are important molecules in the response reactions of algae to this pollutant. Cultivation with PS-MPs systematically reduced the concentration of essential linoleic acid (ALA, C18:3n-3) in C. sorokiniana, concomitantly increasing oleic acid (C18:1n-9). Among the storage triacylglycerols, palmitoleic and oleic acids increased at the expenses of two essential fatty acids, linoleic (LIN, C18:2n-6) and ALA, while PS-MPs had even more pronounced effects on the fatty acid and hydrocarbon composition of waxes and steryl esters. The FA composition of two major chloroplast galactolipids, monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), were affected implying changes in the conformational structure of photosynthetic complexes in ways that can impair the photosynthesis. These data reveal how exposure to polystyrene microplastics can modify the concentrations of lipid molecules that are important intrinsically in cell membranes, and hence the lipid bilayers that could form an important barrier between algal cellular compartments and plastics in the aquatic environment. Changes in lipid synthesis and fatty acid composition in algae could also have repercussions for food quality, growth and stressor resistance in primary consumers. We advocate further studies of microplastics effects on the lipid composition of primary producers, and of their potential propagation through aquatic food webs.

Orientation behavior and swimming speed of Atlantic herring larvae (Clupea harengus) in situ and in laboratory exposures to rotated artificial magnetic fields

The dispersal of fish larvae during the early life stages plays an important role in recruitment. Together with oceanographic processes, larval orientation and swimming behavior significantly influences dispersal. However, currently there is no information of larval behavior in situ for most subpolar species. The Atlantic herring (Clupea harengus) is an ecologically and commercially important component of the North Atlantic ecosystem. This species has sustained a large fishery for over a century, and its stocks have experienced both dramatic collapse and recovery. The Atlantic herring is highly migratory, making it challenging for researchers to determine with certainty the structure and discreteness of different herring stocks. In this context, studying the behavior of herring larvae at sea is crucial for a deeper understanding of their dispersal. However, to date information on the orientation behavior and swimming abilities of herring larvae in situ is missing. In this study, we coupled in situ observations and laboratory experiments to investigate whether herring larvae display orientation when swimming in situ, and which mechanisms/cues they could use. We video recorded the orientation behavior of 208 herring larvae between 14 and 28 days post hatch (DPH) in the coastal Norwegian North Sea while they drifted in transparent behavioral chambers. We also tested the orientation of 136 larvae in a magnetic laboratory, in which they were deprived of any external cue and where we could modify the direction of the magnetic field. We report evidence that herring larvae have a significant preferred orientation direction to the southeast, which does not change between 14 and 28 DPH. Moreover, our results suggest that sunlight plays a key role as larvae had a highly significant orientation towards the sun during sunny weather, but they lost this ability, and exhibited lower precision in their orientation, under an overcast sky. We did not find evidence of magnetic compass orientation, indicating that the orientation direction of herring larvae is not magnetic, at least at this life history stage. Larvae swam at an average speed of 0.36–0.40 cm/s and reached maximum speeds of 3–3.36 cm/s. These results demonstrate that 14–28 DPH herring larvae are capable of orienting in situ. Possible implications of this orientation behavior for larval transport in Norwegian waters are also explored.

Particle Response of Antenna-Coupled TES Arrays: Results from SPIDER and the Laboratory

Future mm-wave and sub-mm space missions will employ large arrays of multiplexed Transition Edge Sensor (TES) bolometers. Such instruments must contend with the high flux of cosmic rays beyond our atmosphere that induce "glitches" in bolometer data, which posed a challenge to data analysis from the Planck bolometers. Future instruments will face the additional challenges of shared substrate wafers and multiplexed readout wiring. In this work we explore the susceptibility of modern TES arrays to the cosmic ray environment of space using two data sets: the 2015 long-duration balloon flight of the SPIDER cosmic microwave background polarimeter, and a laboratory exposure of SPIDER flight hardware to radioactive sources. We find manageable glitch rates and short glitch durations, leading to minimal effect on SPIDER analysis. We constrain energy propagation within the substrate through a study of multi-detector coincidences, and give a preliminary look at pulse shapes in laboratory data.

Bone chemical composition changes in bird bones from laboratory exposure to saline lake conditions

The abundance of bird bones in archeological contexts of high salt is potentially impacted by salinization, which can affect bone preservation. We exposed wing elements (humeri, ulnae, and radii) of domestic chicken (Gallus gallus domesticus) to laboratory conditions simulating a saline lake substrate with overlaying saltwater for up to 32 weeks. Our analyses based on bone ashing and elemental concentration using ICP-OES are reported. The data provide useful taphonomic information regarding changes in bone mineral content, element concentrations, and element to phosphorus ratios of bird bones exposed to saline environments. Results showed that all exposed wing bones increased significantly in bone mineral content, which indicated that wing bones most likely became stronger. Overall, ionic concentrations of Ca2+, K+, Mg2+, Na+, P5+, Sr2+, and Si4+, except Fe3+, changed significantly among all wing bones with saline exposure. These changes in ion concentration took place in as little as 4 weeks. Element to phosphorus ratios provided insight into potential ionic substitutions between the bone and the saline substrate and solution exposure. The results from our study provide direct evidence that the chemical composition of bird bones deposited along saline lake shorelines quickly become altered.

Constitutive compressive behavior of polyurea with exposure to aggressive marine environments

The constitutive behavior of polyurea after prolonged exposure to aggressive marine environments, including saline water, UV radiation and combinations of both, was investigated in this study. A diffusion study was performed at several temperatures to determine the effect of temperature on saline water ingression into the polyurea using Crank's method. This diffusion data coupled with Arrhenius' methodology allowed for the calculation of an acceleration factor relating laboratory exposure time at elevated temperature to real-life service time. Cast cylindrical specimens were exposed to UV radiation, saline water, and various combinations of UV radiation and saline water. These combinations were: a) exposure to saline water followed by UV radiation, b) UV radiation followed by saline water, and c) saline water and then UV radiation followed by saline water. Uniaxial compressive experiments were conducted on both the virgin and exposed specimens at strain rates of 1.7×10−3s−1 and 2.6×103s−1. Under quasi-static loading conditions, the elastic modulus of the polyurea dropped by 73% after 84 days of exposure to saline water at 85 °C. Specimens exposed to UV radiation showed a maximum increase in the elastic modulus of 64% after 20 days of exposure. When tested under dynamic loading conditions, specimens exposed to saline water for 84 days showed a 48% decrease in strain energy while those exposed to UV radiation showed a 45% increase.

Correlation of long-duration exposure and accelerated testing of protected silver mirrors.

The stability of two types of protected silver mirrors was studied by long-term exposure in a clean-room laboratory and mixed-flowing-gas (MFG) accelerated environmental test with two different gas concentrations. The two types of mirrors behaved very differently when exposed to the clean-room air for six years. The mirrors subjected to a reduced Battelle Class II MFG test protocol for 10 days exhibited similar corrosion mechanisms to those exposed to the clean-room air. With further testing of silver mirrors in both field exposures and MFG test conditions, it is feasible that the MFG-accelerated test method can be developed to quantitatively assess the durability of protected silver mirrors in ambient applications.

In Situ Reproductive Bioassay with Caged Gammarus fossarum (Crustacea): Part 1-Gauging the Confounding Influence of Temperature and Water Hardness.

Monitoring the adverse effects of environmental contaminants on the reproduction of invertebrate species in the field remains a challenge in aquatic ecotoxicology. To meet the need for reliable tools for in situ toxicity assessment, we present the first part of a methodological study of the in situ implementation of a reproductive bioassay in Gammarus previously developed for screening the toxicity of chemical compounds during laboratory exposure. To ensure the correct interpretation of the modulation of reproductive markers (molting, fecundity, follicle growth, and embryonic development) in uncontrolled environmental conditions, we experimentally assessed and statistically modeled the variability in the female reproductive cycle during laboratory exposure under several temperature and water hardness conditions. Whereas water hardness did not influence the reproductive cycle, the significant accelerating effect of temperature on the dynamics of molting and marsupial development was finely modeled, by detailing the influence of temperature on the probability of transition between all molt and embryonic stages along the female cycle. In addition, no effect of temperature or water hardness was detected on the number of oocytes and embryos carried by females. Furthermore, the finding that the relative durations of the first 4 molt and embryonic stages are constant whatever the temperature makes it possible to predict the molting dynamics in fluctuating temperature conditions. Because this could allow us to take into account the confounding influence of temperature on the measurement of reproductive markers, the implications of these findings for an optimal in situ implementation of the reproductive bioassay with G. fossarum are discussed. The relevance of this modeling approach during in situ implementation is tested in a companion study. Environ Toxicol Chem 2020;39:667-677. © 2019 SETAC.

Salt Damage in Wood: Controlled Laboratory Exposures and Mechanical Property Measurements

Salt damage in wood can be recognized by its stringy appearance and is frequently observed in wood used in maritime structures and buildings built near the ocean. Whereas salt-damaged wood is common, little is known about the mechanism by which salt water alters the wood structure. There is no information on the effects of salt damage on the mechanical properties of wood. In this study, a laboratory method for creating salt damage in other porous materials was applied to wood. Wood pillars were placed in a reservoir of 5 M NaCl and exposed to a 40% RH environment. Capillary action pulled the salt water to the upper part of the pillars which were dry. Large deposits of effloresced salts were observed. The changes in mechanical properties caused by the salt were measured by the high-energy multiple impact (HEMI) test. Salt damage caused a reduction in the resistance to impact milling (RIM) of 6.5%, and it was concluded that salt damage causes only minor effects on the strength of wood. The tests were not conclusive as the exact mechanism of salt damage in treated wood. However, diffusion of mineral ions through the cell wall was found to be a key step in the salt damage mechanism.

Light exposure decreases infectivity of the Daphnia parasite Pasteuria ramosa

Abstract Climate change is altering light regimes in lakes, which should impact disease outbreaks, since sunlight can harm aquatic pathogens. However, some bacterial endospores are resistant to damage from light, even surviving exposure to UV-C. We examined the sensitivity of Pasteuria ramosa endospores, an aquatic parasite infecting Daphnia zooplankton, to biologically relevant wavelengths of light. Laboratory exposure to increasing intensities of UV-B, UV-A, and visible light significantly decreased P. ramosa infectivity, though there was no effect of spore exposure on parasitic castration of infected hosts. P. ramosa is more sensitive than its Daphnia host to damage by longer wavelength UV-A and visible light; this may enable Daphnia to seek an optimal light environment in the water column, where both UV-B damage and parasitism are minimal. Studies of pathogen light sensitivity help us to uncover factors controlling epidemics in lakes, which is especially important given that water transparency is decreasing in many lakes.

Effect of spirotetramat and 2,4-dichlorophenoxyacetic pesticides on two phytoplankton species ( Monoraphidium griffithii and Coscinodiscus sp.) in a single and compound mixture laboratory exposure

This study was carried out to assess the chronic effects of both an insecticide (spirotetramat) and a herbicide (2,4-Dichlorophenoxyacetic acid) on two phytoplankton species: Monoraphidium griffith...

Laboratory accelerated and field exposure testing of MgRP and MgORP on AA2024-T351: Chemical and electrochemical protection effects

Two Mg-based coatings consisting of Mg-rich primer (MgRP) and MgO-rich primer (MgORP) with and without topcoat were exposed to laboratory accelerated lifecycle testing (LALT) and outdoor field environments. The coatings were tested in parallel exposure studies utilizing ASTM B117, modified ASTM B117 (cyclic wet-dry, dark-UV exposure in ASTM synthetic ocean water), rural inland (Charlottesville, VA), and coastal marine (Kennedy Space Center) field exposure. Several characterization and electrochemical diagnostic techniques were used to continuously assess coating performance as a function of time in various exposures, enabling comparison of LALT to field exposures. The coating systems were evaluated with respect to the intact coating and to a machined scribe defect. The fate of Mg2+ upon dissolution of Mg and MgO with respect to pigment depletion, corrosion product formation, and repartitioning from the coating into the scribe was monitored with XRD and EDS. The capacity for MgRP and MgORP to provide barrier, cathodic, and chemical corrosion protection to AA2024-T351 substrate was evaluated. The ultimate ability of these coatings to protect the AA2024-T351 substrate both in the scribe and under the coating was gauged with optical profilometry assessment of corrosion damage. The Mg and MgO-based coating systems exhibited several desirable aspects of a corrosion preventative coating. The corrosion damage quantified both under the intact coating and within the scribe was much less than the corrosion damage measured on uncoated controls. Within a given exposure, the reduction of corrosion damage in the scribe correlated with the amount of Mg2+ which was released from the coating and repartitioned into the scribe. The open circuit potential of the coated substrate was depressed to more negative potentials than the bare substrate in 5 wt% NaCl, with non-topcoated samples establishing more negative potentials. The barrier properties remained high throughout the exposures for topcoated samples, which also better preserved the pigment from depletion. Comments are made regarding differences between the Mg and MgO-based coatings and the various laboratory and field exposures.

Diet influence on mechanisms of non-specific stress-response in Baikal endemic amphipod species during long-term laboratory exposure

Abstract The purpose of this study was to estimate one of the important aspects of amphipod laboratory culturing — the effect of different types of nutrition on the key biochemical markers widely used in biomonitoring. The study was performed with the Baikal endemic amphipod species Eulimnogammarus verrucosus (Gerstfeldt, 1858), E. cyaneus (Dybowski, 1874), and Gmelinoides fasciatus (Stebbing, 1899). These species are characterized by different ecological properties and evolutionary history. The results of the study demonstrate that a long-term laboratory exposure to different diets has a direct effect on vital and physiological parameters of the species’ adaptation (mortality, weight, protein concentration). Also, feeding imposes its influence on the common stress-markers of oxidative stress (activities of peroxidase, catalase, glutathione S-transferase), and on anaerobic metabolism (activity of lactate dehydrogenase) in Baikal amphipods, and this effect has a species-specific character. The results should be taken into consideration in future ecophysiological experiments performed with amphipods.

Reduced radiation exposure in the cardiac catheterization laboratory with a novel vertical radiation shield.

ObjectivesInvestigation of novel vertical radiation shield (VRS) in reducing operator radiation exposure.BackgroundRadiation exposure to the operator remains an occupational health hazard in the cardiac catheterization laboratory (CCL).MethodsA mannequin simulating an operator was placed near a computational phantom, simulating a patient. Measurement of dose equivalent and Air Kerma located the angle with the highest radiation, followed by a common magnification (8 in.) and comparison of horizontal radiation absorbing pads (HRAP) with or without VRS with two different: CCL, phantoms, and dosimeters. Physician exposure was subsequently measured prospectively with or without VRS during clinical procedures.ResultsDose equivalent and Air Kerma to the mannequin was highest at left anterior oblique (LAO)‐caudal angle (p < .005). Eight‐inch magnification increased mGray by 86.5% and μSv/min by 12.2% compared to 10‐in. (p < .005). Moving 40 cm from the access site lowered μSv/min by 30% (p < .005). With LAO‐caudal angle and 8‐in. magnification, VRS reduced μSv/min by 59%, (p < .005) in one CCL and μSv by 100% (p = .016) in second CCL in addition to HRAP. Prospective study of 177 procedures with HRAP, found VRS lowered μSv by 41.9% (μSv: 15.2 ± 13.4 vs. 26.2 ± 31.4, p = .001) with no difference in mGray. The difference was significant after multivariate adjustment for specified variables (p < .001).ConclusionsOperator radiation exposure is significantly reduced utilizing a novel VRS, HRAP, and distance from the X‐ray tube, and consideration of lower magnification and avoiding LAO‐caudal angles to lower radiation for both operator and patient.

Microcapsulated biocides for the targeted control of invasive bivalves

Invasive alien species (IAS) are one of the greatest drivers of ecological change. Typically, control uses chemical agents that often are ineffective, harmful to non-target organisms, and environmentally persistent. Bivalves are frequently high impact IAS, but have proven particularly hard to control due to their valve-closing response when exposed to conventional control agents. Microencapsulation of biocides with edible coatings represents a highly targeted delivery route, bypassing avoidance responses and accumulating in bivalves through their prodigious filter feeding. Uneaten microcapsules degrade and become biologically inactive within hours thus reducing potential impacts on non-target biota. We manufactured two new formulations of microcapsules (BioBullets). Particles were designed to mimic natural food particles (algae) in terms of size (9.5 ± 0.5 to 19.4 ± 1.3 SE µm diameter), buoyancy (near neutral) and shape (spherical). Laboratory exposures demonstrated that two formulations effectively controlled the Gulf wedge clam Rangia cuneata, an IAS currently spreading rapidly through Europe. A single dose of 2–6 mg L−1 of the active ingredient in a static system achieved 90% mortality after 30 days of exposure. Microencapsulation offers an effective and targeted management tool for rapid responses following the early detection of both Gulf wedge clams and many other filter-feeding IAS, and may be especially effective in closed systems or where populations remain very localised.

Endocrine Disruption and Reproductive Pathology.

During the past 20 years, investigations involving endocrine active substances (EAS) and reproductive toxicity have dominated the landscape of ecotoxicological research. This has occurred in concert with heightened awareness in the scientific community, general public, and governmental entities of the potential consequences of chemical perturbation in humans and wildlife. The exponential growth of experimentation in this field is fueled by our expanding knowledge into the complex nature of endocrine systems and the intricacy of their interactions with xenobiotic agents. Complicating factors include the ever-increasing number of novel receptors and alternate mechanistic pathways that have come to light, effects of chemical mixtures in the environment versus those of single EAS laboratory exposures, the challenge of differentiating endocrine disruption from direct cytotoxicity, and the potential for transgenerational effects. Although initially concerned with EAS effects chiefly in the thyroid glands and reproductive organs, it is now recognized that anthropomorphic substances may also adversely affect the nervous and immune systems via hormonal mechanisms and play substantial roles in metabolic diseases, such as type 2 diabetes and obesity.

Toxicity of microbial insecticides toward the non-target freshwater insect Chironomus xanthus.

Commercial formulations based on Bacillus thuringiensis subs. kurstaki (Btk) and Beauveria bassiana (Bb) are commonly used microbial insecticides in Brazil and other tropical regions. However, and despite being considered environmentally friendly, their use generates concerns regarding possible adverse ecological effects in freshwater ecosystems. Here, we evaluate the effects of these bioinsecticides on the tropical aquatic dipteran Chironomus xanthus under laboratory conditions. After laboratory exposures to these compounds 48-h median lethal concentration (LC50 ) values of 1534 μg a.i./L for Btk and of 6.35 μg a.i./L for Bb were estimated. Chronic assays revealed different sublethal effects: Btk-based bioinsecticide exposure reduced C. xanthus growth [lowest observed effect concentration (LOEC) was 126 μg a.i./L for head width], decreased emergence rate (LOEC = 8 μg a.i./L) and increased immunological response (LOEC = 50 μg a.i./L) measured as total hemocyte count in larvae hemolymph. Exposure to low concentrations of Bb-based insecticide also reduced C. xanthus growth (LOEC = 0.07 μg a.i./L for larvae body length measurements), and emergence rate (LOEC = 0.28 μg a.i./L), despite no clear effects on the total hemocyte counts. Our results suggest that low concentrations of Btk and Bb bioinsecticides are toxic to C. xanthus. Given their widespread use and occurrence in tropical freshwater systems, research is needed to evaluate the potential effects of these compounds concerning natural freshwater insect communities and ecosystem functioning. © 2019 Society of Chemical Industry.