Acute and early life-stage toxicity of atrazine in sheepshead minnow (Cyprinodon variegatus).

Given the limited data available for estuarine/marine fish species and potential risk of being exposed to the herbicide atrazine, additional toxicity data regarding sensitive life-stages are needed. As such, this work sought to characterize: 1) the acute larval toxicity, and 2) early life-stage toxicity of technical atrazine in the model marine species sheepshead minnow (Cyprinodon variegatus). Atrazine was observed to be slightly to moderately toxic towards C. variegatus under acute conditions (as per U.S. EPA 2017 criteria). After 96 h exposure, mortality rates of 5%, 15%, 35%, and 90% were observed among fish exposed to atrazine at 4.6, 7.6, 13, and 22 mg a.i./L, respectively. Sub-lethal effects were observed among surviving fish exposed to > 3.2 mg a.i/L. The 96 h LC50 was 13 mg a.i./L and the NOEC was 3.2 mg a.i./L. In the 33 d early-life stage test, mean embryo survival rates in 0.15, 0.30, 0.57, 1.1, and 2.2 mg a.i./L treatments ranged from 71% to 79% and were not different from survival in the control (78%). Following 28 d post-hatch exposure (Day 33), mean larval survival ranged from 98% to 100% in all treatments and the control. Larval length and wet weight were the most sensitive indicators of the toxicity of atrazine to early life-stage sheepshead minnow. The NOEC for growth was 1.1 mg a.i./L and the LOEC was 2.2 mg a.i./L. Based on these, the MATC for atrazine to sheepshead minnow embryos and larvae was estimated to be 1.6 mg a.i./L. These results were consistent with previous investigations in sheepshead minnow and other marine fish species. Based on the results, atrazine would not be expected to pose unacceptable risks for sheepshead minnow early life-stages at environmentally relevant concentrations.

The challenge of objective scar colour assessment in a clinical setting: using digital photography.

OBJECTIVE: Scar assessment in the clinical setting is typically impeded by a lack of quantitative data and most systems rely on subjective rating scales which are user dependant and show considerable variability between raters. The growing use of digital photography in medicine suggests a more objective approach to scar evaluation. Our objective was to determine if cameras could be of practical use for measuring colour in a clinical setting. METHOD: The measurement of colour and reflectance spectra in photographs faces two difficulties: firstly the effects of variable illumination spectra, and secondly to recover accurate colour and spectral information from the sparse red, green and blue (RGB) camera signals. As a result the colour rendition is often inaccurate, and spectral information is lost. To deal with variable illumination and other factors that systematically affect all reflectance spectra ColourWorker (a method for image-based colour measurement implemented in software) calibrates the spectral responses of the camera's RGB sensors using a colour standard in the image. To make best use of the calibrated signals, it takes advantage of the fact that although a given RGB signal can be caused by an infinite number of spectra, most natural reflectance spectra vary smoothly and have predictable forms. This means given a set of examples of spectra produced by the materials of interest, it is possible to estimate the specific spectrum that produced a given RGB signal once corrected for the illumination. We describe a method for recovering spectral and chromatic information relating to surface reflectance from ordinary digital images and apply this to analyse photographs of surgical scars, taken as part of a clinical trial, in an attempt to better quantify clinical scar assessment. It should be noted the pre-existing trial protocol did not allow for a comprehensive evaluation of the accuracy of the method which would require the spectrophotometric measurement of skin regions corresponding to those in the photographs. RESULTS: Scar colour was estimated reliably, and with simple image analysis we were able to record the change in colour across the skin. Furthermore, we describe a simple automated assessment procedure that enables scar severity to be quantified and defined using a single scalar value easily. CONCLUSION: Such image-based colour measurement and assessment offers considerable advantages over other current methods, including spectrometers, which measure only a single point, or printed charts.

Effectiveness of ozonation treatment in eliminating toxicity of oil sands process-affected water to Chironomus dilutus.

Water soluble organic compounds (OCs), including naphthenic acids (NAs), are potentially toxic constituents of oil sands process-affected water (OSPW) that is generated during extraction of bitumen from Alberta oil sands. Ozonation can decrease concentrations of OCs in OSPW. However, effects of ozonated-OSPW on multicellular organisms are unknown. A 10-day and a chronic exposure of Chironomus dilutus to OSPW were conducted to assess effects on survival, growth, development, and behavior. Two separate batches of OSPW were treated with 30 or 80 mg ozone (O(3))/L. Wet body masses of larvae exposed to OSPW were 64 to 77% less than their respective controls (p < 0.001). However, both levels of ozonation significantly attenuated effects of OSPW on growth. Similarly, chronic exposure to untreated OSPW resulted in significantly less pupation than in the controls, with 31% and 71% less pupation of larvae exposed to the two batches of OSPW (p < 0.05). Emergence was significantly less for larvae exposed to OSPW, with 13% and 8% of larvae emerging, compared to 81% in controls (p < 0.0001). Both levels of ozonation of OSPW attenuated effects on emergence. These results suggest that OCs degraded by ozonation causes toxicity of OSPW toward C. dilutus, and that ozonation attenuates toxicity of OSPW.

Non-Lethal Blood Sampling of Fish in the lab and Field With Methods for Dried Blood Plasma Spot Omic Analyses.

There is global acknowledgment that humane methods in animal research are a priority, but few environmental effects monitoring programs use nonlethal methods for fish. The goal of the present study was to determine the impacts of sampling small volumes of blood in larger-bodied fish on survival and healing. In addition to evaluating survival following blood sampling, we evaluated the utility of dried blood spots as an alternative for sample processing and storage in the field. In our approach, we housed 80 rainbow trout (Oncorhynchus mykiss) in our flow-through aquatic facility. We then anaesthetized using MS-222 and sampled 1 µl/g bw of blood via puncture of the caudal vasculature. We tested four different post-blood sampling treatments on the puncture wound: 1. application of liquid bandage; 2. a swab of betadine; 3. a swab of fish mucous; and 4. compared survival outcomes to a group where no post-treatment was performed (negative control). Overall, we observed 90% survival among all treatments, with the most effective approach being the negative control (100% survival). Based upon these results, we repeated the blood sampling with no-post treatment by housing 20 rainbow trout (not previously tested upon) in cages at a nearby creek and monitored survival for 2 weeks post sampling. The survival rate was 95% with full healing of the puncture site in all subjects. In addition to this, we tested the efficacy of dry blood spotting on proteomic, lipidomic and amino acid analysis as an alternative method for blood sample processing and storage. It was found that dried plasma spotting using parafilm in conjunction with a modified Bligh-Dyer extraction offered the best balance for good recovery of protein, lipid and amino acids relative to wet plasma and Noviplex dried plasma spot cards. In this article, we will present the detailed results of these combined studies and describe what we have determined to be the safest non-lethal blood sampling protocol.

Effect of nozzle selection on deposition of thiamethoxam in Actara® spray drift and implications for off-field risk assessment.

Off-target drift during pesticide spray applications represents a potential pathway for the introduction of active ingredient into field-adjacent water, soils, and/or vegetation. This study investigated the extent of downwind spray drift deposition of thiamethoxam (as a model insecticide) from an application of Actara® 25WG using standard nozzles (TeeJet XR11003, DG11004, and AIXR11002) onto a fallow field test site in the Midwestern USA. Single broadcast applications at a target rate of 96 g a.i./ha were made uniformly via tractor boom to a mowed stubble plot at a spray volume of 93.5 L/ha. Sampling devices (stainless steel disks, filter paper, and stainless steel rods) were located upwind of the spray swath (as negative control samples), within the spray swath (filter paper only), and downwind (all samplers), perpendicular to the spray swath from 12.5 to 400 ft. (3.8 to 122 m) from the edge of the treated field. Comparison of measured residues from the three types of samplers indicated that filter paper generally had greater variability in results than metal disks. When nozzles were compared, the AIXR11002 air induction nozzle produced less off-field deposition than other nozzles tested. Measured downwind concentrations of thiamethoxam from disk samplers were used to predict distances for mitigating potential effects to honey bees. Based on field-derived models, downwind distances from the spray swath required to reduce exposure levels below levels of concern for honey bees varied from <1 ft. to 148 ft. (0.3 to 45 m) depending on the hazard endpoint and nozzle used. These distances were considerably lower than those predicted using the AgDRIFT model, particularly for distances further downwind. At 400 ft. (122 m), AgDRIFT over-predicted the calculated concentrations by up to a factor of 4.8, 7.2, and 10 for DG11004, XR11003, and AIXR11002, respectively. These data suggest that the AgDRIFT model is less reliable for predicting spray deposition at further downwind distances, with implications for risk assessment.

The Updated Neuroradiology Milestones: Synapsing from 1.0 to 2.0.

The Accreditation Council for Graduate Medical Education is currently in the process of specialty-by-specialty revision of the Milestones. As a result, the Neuroradiology Milestones 2.0 Workgroup was created to refine a system of competency-based assessments for fellow educational growth and development. Strengths of the new Milestones include decreased complexity and uniformity within a subcompetency as it relates to a specific educational development trajectory. The Supplemental Guide serves to decrease clutter in the Milestones 2.0 document and provides a more practical resource for guidance. This article serves to review the history of the Neuroradiology Milestones, followed by a summary of the timeline of events and discussions of the workgroup for development of Neuroradiology Milestones 2.0 and a synopsis of major changes. The plan is for the updated Neuroradiology Milestones to take effect in 2021 or 2022 based on public commentary.

Evaluation of cold-weather wastewater nitrification technology for removal of polar chemicals of emerging concern from rural Manitoba wastewaters.

Aerated lagoons, typically used by small communities, often provide limited removal of wastewater nutrients. Given increasingly stringent wastewater standards, it is imperative that effective, but economical and easy-to-operate, treatment technologies be developed. The Submerged Attached Growth Reactor (SAGR®) is a treatment process developed to perform nitrification near freezing temperatures. Previous tests on full-scale installations have shown that SAGR could consistently remove ammonia to below current Canadian standards and provide additional total suspended solids and biochemical oxygen demand removal. In this study, we evaluated removal of polar chemicals of emerging concern (CECs), including pharmaceuticals, personal care products, and pesticides, at SAGR installations in two Manitoba First Nations communities (MCN and LPFN) under cold winter conditions. Both showed some removal of diclofenac, naproxen, clarithromycin, metoprolol, and trimethoprim, likely by biotransformation. Average naproxen removal was 21% (2.53 × 103 ng L-1) in MCN and 64% (1.58 × 103 ng L-1) in LPFN. Atenolol was well-removed by SAGR, by 80% on average (range of 64%-94%). Clarithromycin, metoprolol, and trimethoprim removal was similar within and between systems, ranging from 54% to 76% (30.8-3.07 × 102 ng L-1 removed). Carbamazepine was detected in nearly all samples, but was not well-removed, consistent with other treatment studies. Overall, results showed that SAGR technology could moderately remove CECs, while providing the designed treatment performance for other parameters. This work will help to improve our understanding of wastewater treatment in small and/or remote communities with limited infrastructure and challenging cold-weather conditions.

Glomerular basement membrane proteoglycans are derived from a large precursor.

The basement membrane heparan sulfate proteoglycan produced by the Englebreth-Holm-Swarm (EHS) tumor and by glomeruli were compared by immunological methods. Antibodies to the EHS proteoglycan immunoprecipitated a single precursor protein (Mr = 400,000) from [35S]methionine-pulsed glomeruli, the same size produced by EHS cells. These antibodies detected both heparan sulfate proteoglycans and glycoproteins in extracts of unlabeled glomeruli and glomerular basement membrane. The proteoglycans contained core proteins of varying size (Mr = 150,000 to 400,000) with a Mr = 250,000 species being predominant. The glycoproteins are fragments of the core protein which lack heparan sulfate side chains. Antibodies to glomerular basement membrane proteoglycan immunoprecipitated the precursor protein (Mr = 400,000) synthesized by EHS cells and also reacted with most of the proteolytic fragments of the EHS proteoglycan. This antibody did not, however, react with the P44 fragment, a peptide situated at one end of the EHS proteoglycan core protein. These data suggest that the glomerular basement membrane proteoglycan is synthesized from a large precursor protein which undergoes specific proteolytic processing.

Moderately increased protein intake predominately from egg sources does not influence whole body, regional, or muscle composition responses to resistance training in older people.

UNLABELLED: The effects of increased dietary protein on resistance training (RT)-induced changes in body composition and skeletal muscle fiber size are uncertain in older people. OBJECTIVES: We hypothesized that the ingestion of more animal-based foods, especially eggs, to achieve a higher protein intake would enhance RT-induced changes in body composition. SETTING: West Lafayette, IN. PARTICIPANTS: 36 older people (age 61 +/- 1 y; mean +/- SEM). INTERVENTION: Subjects completed RT three d/wk for 12 weeks, and consumed omnivorous diets that contained either 0.9 +/- 0.1 (lower protein) or 1.2 +/- 0.0 (higher protein) g protein x kg(-1) x d(-1) (12 +/- 3 and 17 +/- 5% of energy intakes, respectively), with the higher protein intake achieved by consuming more eggs, meats, and dairy foods. The lower and higher protein diets contained 213 +/- 21 and 610 +/- 105 mg cholesterol/d, respectively. MEASUREMENTS: Strength, body composition, serum lipid-lipoprotein profile, urinary creatinine, skeletal muscle fiber type and size. RESULTS: Among all subjects, over time (i.e. with RT) body weight was unchanged, lean mass (1.1 +/- 0.2 kg) increased, and fat mass (-1.4 +/- 0.2 kg) decreased (all changes P < 0.05). Regional (i.e. trunk, legs, arms) lean mass increased and fat mass decreased. Whole body muscle mass (24-h urinary creatinine excretion) increased, but skeletal muscle (vastus lateralis) type 1, type 2a, and type 2x fiber cross-sectional areas did not change from baseline. Serum total and LDL cholesterol decreased (P < 0.05) and HDL cholesterol and triacylglycerol were unchanged. Dietary protein and cholesterol intakes did not influence these responses to RT. CONCLUSION: Consumption of diets that contained moderately higher protein and variable amounts of cholesterol did not differentially affect body composition, skeletal muscle fiber size, or serum lipid-lipoprotein profile responses to resistance training in older people.

Does bouton morphology optimize axon length?

The total length of cortical axons could be reduced if the parent axons maintained straight trajectories and simply connected to dendritic shafts via spine-like terminaux boutons and to dendritic spines via bead-like en passant boutons. Cortical axons from cat area 17 were reconstructed from serial electron micrographs and their bouton morphology was correlated with their synaptic targets. En passant or terminaux boutons did not differ in the proportion of synapses they formed with dendritic spines and shafts, and thus, the two morphological variants of synaptic bouton do not contribute directly to optimizing axon length.

Dendritic asymmetry cannot account for directional responses of neurons in visual cortex.

A simple model was proposed to account for the direction selectivity of neurons in the primary visual cortex, area V1. In this model, the temporal asymmetries in the summation of inhibition and excitation that produce directionality were generated by structural asymmetries in the tangential organization of the basal dendritic tree of cortical neurons. We reconstructed dendritic trees of neurons with known direction preferences and found no correlation between the small biases of a neuron's dendritic morphology and its direction preference. Detailed simulations indicated that even when the electrotonic asymmetries in the dendrites were extreme, as in cortical Meynert cells, the biophysical properties of single neurons could contribute only partially to the directionality of cortical neurons.

The metabolic cost of neural information.

We derive experimentally based estimates of the energy used by neural mechanisms to code known quantities of information. Biophysical measurements from cells in the blowfly retina yield estimates of the ATP required to generate graded (analog) electrical signals that transmit known amounts of information. Energy consumption is several orders of magnitude greater than the thermodynamic minimum. It costs 10(4) ATP molecules to transmit a bit at a chemical synapse, and 10(6)-10(7) ATP for graded signals in an interneuron or a photoreceptor, or for spike coding. Therefore, in noise-limited signaling systems, a weak pathway of low capacity transmits information more economically, which promotes the distribution of information among multiple pathways.

Comparison of adjuvant chemotherapeutic activity against primary and metastatic spontaneous murine tumors.

Metastatic tumor incidence in BALB/C X DBA/8F1 female mice was examined in the presence and absence of adjuvant chemotherapy. Following surgical removal of spontaneous mammary adenocarcinomas, phenylalanine mustard, adriamycin, and 5-fluorouracil (PAF) were administered at 4, 2, and 50 mg/kg, respectively, once a week for six injections. Recurring tumors and new tumors developing in other breasts over the next 6 months were noted and surgically removed to allow time for originally undetectable pulmonary metastases to develop or to regress completely. This regimen of PAF significantly decreased original tumor recurrences from 58% in controls to 36% in treated mice. New tumor development also was significantly reduced during the 5 weeks of PAF therapy and for 8 weeks thereafter. However, the incidence of pulmonary metastasis was unaffected by the chemotherapy, being 42% in controls and 37% in PAF-treated mice. About 30% of these metastases would have been undetectable at the time of original surgery. The findings stress the importance of developing agents and/or schedules that will specifically affect metastatic cells when administered early to minimal numbers of tumor cells. This system represents a stringent clinimimetic model for evaluating adjuvant chemotherapy in this regard.

Isolation of a glycoprotein and proteodermatan sulphate from bovine achilles tendon by affinity chromatography on concanavalin A-Sepharose.

A fraction was isolated from a 3 M MgCl2 extract of bovine achilles tendon on the basis of its affinity for collagen. Affinity chromatography of this material on concanavalin A-Sepharose yielded a mixture which comprised a glycoprotein of approximate molecular weight 60 000 and two constituents containing hexuronic acid. The existence of a complex between the glycoprotein and material containing hexuronic acid was demonstrated by chromatography on Sephadex G-200 and by equilibrium sedimentation in CsCl density gradients. The complex was completely dissociated in 4 M guanidinium chloride. One of the constituents containing hexuronic acid was identified as a proteodermatan sulphate of low molecular weight and which had an abnormally high protein content (45-50%) and low buoyant density (1.46 g/ml) for a proteoglycan. The denser of the two molecules containing hexuronic acid appeared to be a normal proteoglycan, with a low protein content (11%). Analyses are given for the glycoprotein and the proteodermatan sulphate.

Distribution in caesium chloride gradients of proteoglycans secreted by bovine aorta smooth muscle cells and study of their aggregation with hyaluronate and cartilage proteoglycan.

Smooth muscle cells from media of bovine aorta were cultured with [35S] sulphate and [3H]glucosamine. The 4 M guanidinium chloride extract of cell layer had a greater proportion of its glycosaminoglycans as hyaluronic acid, heparan sulphate and dermatan sulphate than did medium, which contained relatively more chondroitin sulphate. Fractionation of medium and cell layer extract by caesium chloride density gradient centrifugation, under associative and dissociative conditions, respectively, established that heparan sulphate and dermatan sulphate proteoglycans had lower buoyant densities than chondroitin sulphate proteoglycans. Chromatography on Sepharose CL2B showed that chondroitin sulphate-rich proteoglycan from medium bottom fraction contained no high molecular weight aggregate but underwent partial reaggregation with hyaluronic acid. A slight shift to higher molecular weight occurred if cartilage proteoglycan monomer was added to medium bottom fraction, but if both hyaluronic acid and cartilage proteoglycan monomer were added, a high degree of aggregation took place. These observations could be explained if medium bottom fraction contained a proteoglycan-deficient aggregate with a low molecular weight hyaluronate species. Bottom fraction from cell layer extract showed none of these properties.

Increased hyaluronate synthesis and changes in glycosaminoglycan ratios and molecular weight of proteoglycans synthesised by cultured cervical tissue from ewes at various stages of pregnancy.

Culture of cervical tissue with radiolabelled precursors showed that, in pregnant ewes, net hyaluronate synthesis increased between days 120-140 but that the marked polydispersity of hyaluronate remained unchanged. In the less sulphated of two proteoglycan populations, the proportion of heparan sulphate increased and that of dermatan sulphate decreased, while the less polydisperse more highly sulphated species showed a significant increase in molecular weight with pregnancy.

The value of hepatic ultrasound and biochemical liver tests in screening for liver metastases.

The records of 92 patients with a known diagnosis of extrahepatic cancer who had undergone hepatic ultrasound, biochemical liver tests (alkaline phosphatase, SGOT, lactic dehydrogenase, and bilirubin levels), and subsequent liver biopsy or autopsy within a 6-week period were reviewed. The sensitivity, specificity, and accuracy of the ultrasound and biochemical tests in the detection of metastatic liver disease were calculated. Although there was no significant difference in the sensitivity of either examination, the ultrasound demonstrated higher specificity and accuracy than the biochemical liver tests. The high sensitivity of hepatic ultrasound prevailed even in patients with normal biochemical liver tests. The sensitivity of hepatic ultrasound was significantly lower in patients with lymphoma compared with patients with colorectal cancer (50% v 100%, P less than .05). Notable incidental extrahepatic findings were reported in 25% of the ultrasound examinations. In institutions skilled in sonography, hepatic ultrasound may be a superior tool in the detection of liver metastases in most solid tumors, excluding lymphoma, and offers the additional advantage of simultaneous biliary tract and perihepatic visualization.

Expanding the genetic code: selection of efficient suppressors of four-base codons and identification of "shifty" four-base codons with a library approach in Escherichia coli.

Naturally occurring tRNA mutants are known that suppress +1 frameshift mutations by means of an extended anticodon loop, and a few have been used in protein mutagenesis. In an effort to expand the number of possible ways to uniquely and efficiently encode unnatural amino acids, we have devised a general strategy to select tRNAs with the ability to suppress four-base codons from a library of tRNAs with randomized 8 or 9 nt anticodon loops. Our selectants included both known and novel suppressible four-base codons and resulted in a set of very efficient, non-cross-reactive tRNA/four-base codon pairs for AGGA, UAGA, CCCU and CUAG. The most efficient four-base codon suppressors had Watson-Crick complementary anticodons, and the sequences of the anticodon loops outside of the anticodons varied with the anticodon. Additionally, four-base codon reporter libraries were used to identify "shifty" sites at which +1 frameshifting is most favorable in the absence of suppressor tRNAs in Escherichia coli. We intend to use these tRNAs to explore the limits of unnatural polypeptide biosynthesis, both in vitro and eventually in vivo. In addition, this selection strategy is being extended to identify novel five- and six-base codon suppressors.

DSM-III disorders in preadolescent children. Prevalence in a large sample from the general population.

We investigated the prevalence of DSM-III disorders in 792 children aged 11 years from the general population and found an overall prevalence of disorder of 17.6% with a sex ratio (boys-girls) of 1.7:1. The most prevalent disorders were attention deficit, oppositional, and separation anxiety disorders, and the least prevalent were depression and social phobia. Conduct disorder, overanxious disorder, and simple phobia had intermediate prevalences. Pervasive disorders, reported by more than one source, had an overall prevalence of 7.3%. Examination of background behavioral data disclosed that children identified at 11 years as having multiple disorders had a history of behavior problems since 5 years of age on parent and teacher reports. Fifty-five percent of the disorders occurred in combination with one or more other disorders, and 45% as a single disorder.

Depression in a sample of 9-year-old children, Prevalence and associated characteristics.

We investigated the prevalence of depression in a sample of 9-year-old children from the general population being studied longitudinally. Current point prevalences of major and minor depressive disorder were estimated at 1.8% and 2.5%, respectively. A comparison of children with depression and a nondepressed group disclosed no significant differences by sex, nor any significant association between depression and socioeconomic status, teacher reports of behavior problems, and cognitive or motor development. The children with current depression were reported by a parent to have had a history of more behavioral problems, had been referred more often for assessment or treatment of behavioral or emotional problems, and had more negative self-perceptions of their academic ability. The results suggested that parents may be more sensitive than teachers to the behavior problems exhibited by depressed children.