30 results on '"Varela JL"'
Search Results
2. Feeding of Atlantic bluefin tuna Thunnus thynnus around the Canary Islands assessed from stomach content and stable isotope analyses
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Varela, JL, primary, Medina, A, additional, Déniz, S, additional, and Abascal, FJ, additional
- Published
- 2022
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3. ESTUDIO PRELIMINAR DE LA BIOLOGÍA Y PESQUERÍA DEL PEZ SABLE (Lepidopus caudatus) EN EL GOLFO DE CÁDIZ
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Prada, Pablo Jimenez, J, Gil, and Varela JL
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- 2013
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4. Capacitive electrode with high sensitivity for detection of electrical biopotentials
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Varela, JL, primary, Rivera, JO, additional, Espina, JH, additional, and de la Rosa, JM, additional
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- 2015
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5. Feeding patterns of age-0 bluefin tuna in the western Mediterranean inferred from stomach-content and isotope analyses
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Medina, A, primary, Goñi, N, additional, Arrizabalaga, H, additional, and Varela, JL, additional
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- 2015
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6. The gills and skin microbiota of five pelagic fish species from the Atlantic Ocean.
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Varela JL, Nikouli E, Medina A, Papaspyrou S, and Kormas K
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- Animals, Atlantic Ocean, Phylogeny, DNA, Bacterial genetics, Gills microbiology, Microbiota, Skin microbiology, Bacteria classification, Bacteria genetics, Bacteria isolation & purification, Bacteria metabolism, RNA, Ribosomal, 16S genetics, Fishes microbiology
- Abstract
The gills and skin microbiota and microbiome of wild fish remain far more under-investigated compared to that of farmed fish species, despite that these animal-microbe interactions hold the same ecophysiological roles in both cases. In this study, the gills and skin bacterial microbiota profiles and their presumptive bacterial metabolisms were investigated in five open-sea fishes: bullet tuna (Auxis sp.), common dolphinfish (Coryphaena hippurus), Atlantic little tunny (Euthynnus alletteratus), Atlantic bonito (Sarda sarda) and Atlantic white marlin (Kajikia albida). Gills and skin tissues were collected from two to three individuals per species, from specimens caught by recreational trolling during summer of 2019, and their bacterial 16S rRNA gene diversity was analysed by high-throughput sequencing. The gills bacterial communities among the five species were clearly different but not the skin bacterial microbiota. The dominant operational taxonomic units belonged to the Moraxellaceae, Pseudomonadaceae, Rhodobacteraceae, Staphylococcaceae and Vibrionaceae families. Despite the differences in taxonomic composition, the presumptive bacterial metabolisms between the gills and skin of the five fishes investigated here were ≥ 94% similar and were dominated by basic metabolism, most likely reflecting the continuous exposure of these tissues in the surrounding seawater., Competing Interests: Declarations. Ethical approval: Not applicable. Competing interests: The authors have no competing interests., (© 2024. The Author(s).)
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- 2025
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7. Body size and isotopic profiles enable discrimination between long-term resident and highly migrant contingents of Atlantic bluefin tuna.
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Medina A, Magro A, Abascal FJ, and Varela JL
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- Animals, Atlantic Ocean, Mediterranean Sea, Population Dynamics, Carbon Isotopes analysis, Nitrogen Isotopes analysis, Environmental Monitoring, Tuna, Animal Migration, Body Size
- Abstract
The Atlantic bluefin tuna (ABFT) population ranges throughout the Atlantic Ocean and Mediterranean Sea, and consists of multiple contingents that use diverse habitats and show different movement patterns over the life cycle. Based on body size, elemental and isotopic data of C and N in muscle and liver, we analysed eastern-stock ABFT by comparing mid-sized individuals caught by hook-and-line gears with larger individuals harvested from traps in the Strait of Gibraltar (SoG). Our results show that trophic-related chemical markers have potential for separating temporarily sympatric contingents throughout the ABFT population range, reflecting size-dependent spatial distribution and differential patterns of residency and migration. We present evidence of long-term residency of ABFT in the SoG that persists until the estimated age of ∼5 years (size of ∼140 cm in straight fork length). This age apparently marks a turning point in the life history, where there occurs an ontogenetic switch in the migratory behaviour and distributional pattern. This study contributes new insight into our knowledge about size structure and residency-movement patterns in eastern ABFT. It shows distinct size-dependent migratory and spatial dynamics. The present results encourage further investigation on poorly studied ABFT contingents for a better understanding of the population dynamics towards more comprehensive management plans., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
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- 2024
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8. A systematic review of the utility of continuous performance tests among adults with ADHD.
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Varela JL, Magnante AT, Miskey HM, Ord AS, Eldridge A, and Shura RD
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- Adult, Humans, Psychomotor Performance physiology, Attention Deficit Disorder with Hyperactivity diagnosis, Neuropsychological Tests standards
- Abstract
Objective: The clinical utility of continuous performance tests (CPTs) among adults with attention-deficit/hyperactivity disorder (ADHD) has increasingly been brought under question. Therefore, the objective of this study was to systematically review the literature to investigate the clinical utility of various commercially available CPTs, including the Conner's Continuous Performance Test (CCPT), Test of Variables of Attention (TOVA), Gordon Diagnostic System (GDS), and Integrated Visual and Auditory Continuous Performance Test (IVA) in the adult ADHD population., Methods: This systematic review followed the a priori PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Articles were gathered from PsycINFO, PsycARTICLES, Academic Search Complete, and Google Scholar on 11 April 2022. Sixty-nine articles were included in the final review. Risk of bias was assessed using the National Institute of Health Quality Assessment Took for Observational Cohort and Cross-Sectional Studies., Results: Most articles demonstrated high risk of bias, and there was substantial heterogeneity across studies. Overall, the reviewed CPTs appeared to have limited diagnostic utility and classification accuracy. Although many studies showed differing scores between adults with ADHD and comparison groups, findings were not consistent. Characteristics of CPT performances among adults with ADHD were mixed, with little consistency and no evidence of a clear profile of performances; however, CCPT commission errors appeared to have the most utility when used a treatment or experimental outcome measure, compared to other CCPT scores., Conclusion: Overall, CPTs should not be used in isolation as a diagnostic test but may be beneficial when used as a component of a comprehensive assessment.
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- 2024
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9. Genetic Sex and Origin Identification Suggests Differential Migration of Male and Female Atlantic Bluefin Tuna ( Thunnus thynnus ) in the Northeast Atlantic.
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Nielsen EE, Birnie-Gauvin K, Baktoft H, Arrizabalaga H, Brodin T, Cardinale M, Casini M, Helström G, Jansen T, Koed A, Lundberg P, MacKenzie BR, Medina A, Post S, Rodriguez-Ezpeleta N, Sundelöf A, Varela JL, and Aarestrup K
- Abstract
Knowledge about sex-specific difference in life-history traits-like growth, mortality, or behavior-is of key importance for management and conservation as these parameters are essential for predictive modeling of population sustainability. We applied a newly developed molecular sex identification method, in combination with a SNP (single nucleotide polymorphism) panel for inferring the population of origin, for more than 300 large Atlantic bluefin tuna (ABFT) collected over several years from newly reclaimed feeding grounds in the Northeast Atlantic. The vast majority (95%) of individuals were genetically assigned to the eastern Atlantic population, which migrates between spawning grounds in the Mediterranean and feeding grounds in the Northeast Atlantic. We found a consistent pattern of a male bias among the eastern Atlantic individuals, with a 4-year mean of 63% males (59%-65%). Males were most prominent within the smallest (< 230 cm) and largest (> 250 cm) length classes, while the sex ratio was close to 1:1 for intermediate sizes (230-250 cm). The results from this new, widely applicable, and noninvasive approach suggests differential occupancy or migration timing of ABFT males and females, which cannot be explained alone by sex-specific differences in growth. Our findings are corroborated by previous traditional studies of sex ratios in dead ABFT from the Atlantic, the Mediterranean, and the Gulf of Mexico. In concert with observed differences in growth and mortality rates between the sexes, these findings should be recognized in order to sustainably manage the resource, maintain productivity, and conserve diversity within the species., Competing Interests: The authors declare no conflicts of interest., (© 2024 The Author(s). Evolutionary Applications published by John Wiley & Sons Ltd.)
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- 2024
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10. Preliminary evidence for digit span performance validity indicators within the neuropsychological assessment battery.
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Varela JL, Ord AS, Phillips JI, Shura RD, and Sautter SW
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- Humans, Adult, Middle Aged, Male, Female, Aged, Young Adult, Reproducibility of Results, Retrospective Studies, Sensitivity and Specificity, Neuropsychological Tests standards
- Abstract
The purpose of this study was to evaluate multiple embedded performance validity indicators within the Digits Forward and Digits Backward subtests of the Neuropsychological Assessment Battery (NAB), including Reliable Digit Span (RDS), as no published papers have examined embedded digit span validity indicators within these subtests of the NAB. Retrospective archival chart review was conducted at an outpatient neuropsychology clinic. Participants were 92 adults (ages 19-68) who completed NAB Digits Forward and Digits Backward, and the Word Choice Test (WCT). Receiver operating characteristic (ROC) curves, t -tests, and sensitivity and specificity analyses were conducted. Analyses showed that RDS demonstrated acceptable classification accuracy between those who passed the WCT and those who did not. The area under the curve (AUC) value for RDS was 0.702; however, AUC values for all other digit span indices were unacceptably low. The optimal cutoff for RDS was identified (<8). RDS for the NAB appears to be an adequate indicator of performance validity; however, considering the very small number of participants who were invalid on the WCT ( n = 15), as well as the utilization of only one stand-alone PVT to classify validity status, these findings are preliminary and in need of replication.
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- 2024
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11. A survey of neuropsychological assessment feedback practices among neuropsychologists.
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Varela JL, Sperling SA, Block C, O'Leary K, Hart ES, and Kiselica AM
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- Humans, United States, Feedback, Neuropsychological Tests, Surveys and Questionnaires, Pandemics, Neuropsychology methods
- Abstract
Objective: Feedback on neuropsychological assessment is a critical part of clinical practice, but there are few empirical papers on neuropsychological feedback practices. We sought to fill this gap in the literature by surveying practicing neuropsychologists in the United States. Questions addressed how they provide verbal and written feedback to patients and referral sources. Survey questions also addressed billing practices and training in the provision of feedback., Methods: A survey was developed using Qualtrics XM to survey currently licensed, independently practicing clinical neuropsychologists in the United States about their feedback practices. The survey was completed by 184 individuals., Results: Nearly all respondents reported that they provide verbal feedback to patients, most often in-person, within three weeks following testing. Typically, verbal feedback sessions with patients last 45 min. Verbal feedback was provided to referrals by about half of our sample, typically via a brief phone call. Most participants also reported providing written feedback to both the patient and referring provider, most commonly via the written report within three weeks after testing. Regarding billing, most respondents use neuropsychological testing evaluation codes. The COVID-19 pandemic appeared to have had a limited impact on the perceived effectiveness and quality of verbal feedback sessions. Finally, respondents reported that across major stages of professional development, training in the provision of feedback gradually increased but was considered inadequate by many participants., Conclusions: Results provide an empirical summary of the "state of current practice" for providing neuropsychological assessment feedback. Further experimental research is needed to develop an evidence-base for effective feedback practices.
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- 2024
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12. Assessment of metal and organic pollutants in combination with stable isotope analysis in tunas from the Gulf of Cadiz (east Atlantic).
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Pintado-Herrera MG, López-López JA, Lara-Martín PA, Medina A, Cadenas I, Giansiracusa S, Corada-Fernández C, and Varela JL
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- Humans, Animals, Tuna, Isotopes analysis, Food Chain, Environmental Pollutants, Metals, Heavy analysis
- Abstract
Bioaccumulation patterns of heavy metals (Pb, Cd, Cr, Ni, Fe and Cu) and organic (priority and emerging) pollutants, in combination with stable isotope analysis (SIA), were assessed in muscle and liver of three tuna species from the Gulf of Cadiz (Atlantic bluefin tuna, Thunnus thynnus; Atlantic bonito, Sarda sarda, and skipjack tuna, Katsuwonus pelamis). SIA and contaminant (heavy metal and organic) profiles separately discriminated between species. There was no significant overlap between the trophic niches estimated from isotopic data, suggesting that there are diet differences which may determine differential bioaccumulation patterns. The levels of heavy metals and persistent organic pollutants in muscle of all the individuals analyzed were below the allowable limits established by the current legislation. Concentrations of most contaminants were higher in liver than in muscle, underlining the powerful detoxifying capacity of the liver in tunas. In addition to diet, other factors such as size and age (exposure time to environmental chemicals) explain differences in pollutant accumulation patterns in tissues between species, each with varying degrees of involvement depending on the pollutant class. Our results show that combining contaminant profile data with trophic features based on SIA may help understand pollutant bioaccumulation patterns in upper levels of marine food webs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2024
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13. Otolith-temperature estimates in Atlantic bluefin tuna (Thunnus thynnus) from the Mediterranean Sea: Insights from clumped isotope measurements.
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Artetxe-Arrate I, Brophy D, Dettman DL, Lastra-Luque P, Varela JL, Oray I, Arrizabalaga H, and Fraile I
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- Animals, Temperature, Mediterranean Sea, Isotopes, Oxygen, Atlantic Ocean, Tuna, Otolithic Membrane
- Abstract
The subpopulation and/or contingent structure of Atlantic bluefin tuna (Thunnus thynnus) within the Mediterranean Sea is undefined, leading to uncertainty regarding the best strategy for an effective assessment and management of this highly exploited stock. This study aimed to reconstruct temperatures experienced by Atlantic bluefin tuna during the early life period (<3.5 months) using clumped isotope temperature proxy, an innovative geothermometer for carbonates, that does not require previous knowledge of other environmental parameters such as water oxygen composition. We examined otolith chemistry in fish captured from 3 different areas of the Mediterranean Sea and adjacent waters. We found that mean seasonal temperature estimates from clumped isotopes did not differ significantly from satellite derived and otolith oxygen stable isotopic ratios derived temperatures, except for the central Mediterranean Sea, were clumped isotopes derived temperatures were significantly higher than satellite derived temperatures. However, the sensitivity of the clumped isotope thermometer was found to be lower than that based on oxygen fractionation equation, with high variance observed in the clumped isotopes derived temperature estimates. We also observed that clumped isotope derived temperatures were undistinguishable among bluefin tuna captured in the Gibraltar Strait, the central, and eastern Mediterranean Sea. In this paper, we discuss the major sources of uncertainty in temperature reconstructions using bluefin tuna otoliths., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Iraide Artetxe-Arrate reports financial support was provided by International Commission for the Conservation of Atlantic Tunas., (Copyright © 2023. Published by Elsevier Ltd.)
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- 2024
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14. Chemical signatures in fin spine edge of Atlantic bluefin tuna ( Thunnus thynnus ) can serve as habitat markers of geographically distinct marine environments.
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Luque PL, Artetxe-Arrate I, Bidegain G, Sakai S, Claverie F, Pécheyran C, Fraile I, Murua H, Varela JL, Medina A, and Arrizabalaga H
- Abstract
Chemical fingerprints in otoliths are commonly used as natural habitat markers in fishes. Alternatively, the first dorsal fin spine can provide valuable chemical information and may be more suitable for studying (i) endangered fish species that cannot be sacrificed for their otoliths or (ii) fishes for which otoliths might not be available because of management or commercial reasons. Here, we studied multi-element chemistry of fin spine edges collected from Atlantic bluefin tuna (ABFT; Thunnus thynnus ) (Linnaeus, 1758) to investigate the utility of the fin spine edge as a natural habitat marker. We determined stable isotopic δ
18 O and δ13 C ratios, as well as concentrations of the tracer elements Mg, Mn, Li, Ba, and Sr, at the edge of ABFT fin spines, and then we used these measures to discriminate ABFT individuals among capture regions (i.e., the eastern Atlantic Ocean or Mediterranean Sea). Isotope ratios and tracer element concentrations, and especially a combined multi-element approach, were able to effectively discriminate individuals by capture region. The Mg, Mn, Li, and δ18 O concentrations were the strongest variables driving this discrimination. Overall, our results demonstrate that chemical signatures are consistently retained in the ABFT fin spine edge and support the use of fin spine edges for discerning habitat use. The fin spine chemistry as a minimally invasive sampling method, combined with otolith chemistry, genetic markers, and tagging efforts can help us to reconstruct fish movements, providing a deeper understanding of the spatial population dynamics of this iconic fish species., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)- Published
- 2022
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15. The Development and Validation of the Embedded Validity Indicator for the Neuropsychological Assessment Battery.
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Varela JL, Ord AS, Phillips JI, Shura RD, and Sautter SW
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- Adolescent, Adult, Aged, Humans, Middle Aged, Neuropsychological Tests, Psychometrics, ROC Curve, Reproducibility of Results, Young Adult, Retrospective Studies
- Abstract
Objective: The purpose of this study was to develop and validate an embedded measure of performance validity within the Neuropsychological Assessment Battery (NAB)., Method: This study involved a retrospective chart review at an outpatient neuropsychology clinic. Participants were 183 adults (ages 18-70) who completed the attention and memory modules of the NAB, as well as the Word Choice Test, Green's Medical Symptom Validity Test (MSVT), and Green's Non-Verbal MSVT, as part of a clinical neuropsychological assessment (n = 147) or as part of a forensic neuropsychological evaluation (n = 36). Replicating methodology utilized by Silverberg et al. (2007) for the development of the Effort Index within the Repeatable Battery for the Assessment of Neuropsychological Status, an Embedded Validity Indictor (EVI) for the NAB was developed in the present study based on Digits Forward and List Learning Long Delayed Forced-Choice Recognition (list recognition) subtests., Results: Receiver operating characteristic curve analyses indicated the newly developed NAB EVI was able to significantly differentiate between valid and invalid status on stand-alone performance-validity tests, with area under the curve values ranging from 0.797 to 0.977. Optimal cutoffs for medical, forensic, and mixed samples were identified., Conclusions: The newly developed NAB EVI shows promise as an embedded performance validity measure; however, due to moderate sensitivity, it should be used in combination with stand-alone performance validity tests to detect invalid performance., (© The Author(s) 2021. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)
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- 2022
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16. Running on empty? Freshwater feeding by spawning anadromous alewife Alosa pseudoharengus.
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Stewart SID, Spares AD, Varela JL, McLellan NR, and Stokesbury MJW
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- Animals, Diet, Estuaries, Female, Fishes, Lakes, Ephemeroptera
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Anadromous alewife Alosa pseudoharengus (n = 202; mean ± s.d. fork length = 231 ± 14 mm) were captured from 10 May to 27 June 2018 in an upper watershed lake on the Isthmus of Chignecto, Canada (45°57'N, 64°14'W). Thirty individuals (mean ± s.d. fork length = 250 ± 12 mm) were captured in an adjacent estuary downstream of a tide gate on 25 April 2018. Comparing estuarine to freshwater specimens, mean gonad mass and gonadosomatic indices in males and females decreased approximately 40% and 60%, and 31% and 50%, respectively. Individuals were characterized as pre-spawners in the estuary and spawners in the lake. Males maintained similar body condition throughout the spawning run whereas female condition decreased 9.4% between the estuary and lake. Stomach fullness decreased comparing estuarine and freshwater specimens, yet 93% of stomachs examined from individuals captured in the lake contained prey. Most males fed throughout all spawning stages (3%-17% empty stomachs), while all females fed during pre- and post-spawning stages and some fasted during spawning (11% empty stomachs). Cumulative prey curve never reached an asymptote, either weekly or for the entire sampling period, so freshwater diet may not have been completely described. Calanoid copepods (79.3%I
A ) were a diet staple, with the secondary prey of mayfly nymphs (O. Ephemeroptera) consumed more by females (13.6%IA ) than males (6.2%IA ). PERMANOVA and PERMDISP analyses revealed significant dietary differences in freshwater were weekly and not due to dispersion effects, thus most likely due to feeding on various development stages of insect species. Our results challenge the long-held paradigm that anadromous A. pseudoharengus fast during the spawning migration., (© 2021 Fisheries Society of the British Isles.)- Published
- 2021
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17. An autofluorescence-based survey of late follicular atresia in ovaries of a teleost fish (Thunnus thynnus).
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Medina A, Magro A, Paullada-Salmerón JA, and Varela JL
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- Animals, Female, Fishes, Ovarian Follicle, Tuna, Follicular Atresia, Ovary
- Abstract
In this study, the authors examined late atretic follicles in the ovaries of Atlantic bluefin tuna, Thunnus thynnus (Linnaeus 1758), at different times of the year using transmitted light and epifluorescence microscopy. Atresia (degeneration and resorption of developing ovarian follicles) is a natural process involved in fecundity downregulation in teleosts and is substantially enhanced in stressful conditions. Early (α and β) atretic stages of yolked oocytes have a relatively short duration in seasonally reproducing species, whereas later (γ and δ) atretic follicles (LAF) persist for longer time in the ovary, serving as a sign of previous vitellogenic activity. LAF can thus be used as reliable markers of maturity during non-reproductive periods. Lipofuscin granules accumulate in the cytoplasm of LAF cells as a result of lysosomal digestion of oocyte components. Taking advantage of the well-known autofluorescent properties of lipofuscins, LAF may be identified in unstained histological sections under fluorescence microscopy using appropriate excitation and emission wavelengths. The authors explore in this study the applicability of fluorescence microscopy to provide a fast and effective method to assess late atresia in fishes. This method may be particularly useful to determine sexual maturity in individuals sampled long after the spawning season, where LAF are difficult to detect in standard histological sections. Furthermore, LAF autofluorescence provides a rapid way to quantify late atresia in fishes using image analysis., (© 2021 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles.)
- Published
- 2021
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18. Early type I IFN blockade improves the efficacy of viral vaccines.
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Palacio N, Dangi T, Chung YR, Wang Y, Loredo-Varela JL, Zhang Z, and Penaloza-MacMaster P
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- Animals, Antibodies, Blocking immunology, Antibodies, Blocking pharmacology, Antibodies, Viral immunology, Antigen Presentation immunology, CD8-Positive T-Lymphocytes metabolism, Dendritic Cells immunology, Disease Models, Animal, Gene Expression immunology, HEK293 Cells, Humans, Immunologic Memory, Interferon-alpha genetics, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Mice, Knockout, Receptor, Interferon alpha-beta genetics, Transfection, Zika Virus Infection virology, Immunogenicity, Vaccine immunology, Interferon Type I antagonists & inhibitors, Interferon-alpha immunology, Receptor, Interferon alpha-beta immunology, Viral Vaccines immunology, Zika Virus immunology, Zika Virus Infection immunology
- Abstract
Type I interferons (IFN-I) are a major antiviral defense and are critical for the activation of the adaptive immune system. However, early viral clearance by IFN-I could limit antigen availability, which could in turn impinge upon the priming of the adaptive immune system. In this study, we hypothesized that transient IFN-I blockade could increase antigen presentation after acute viral infection. To test this hypothesis, we infected mice with viruses coadministered with a single dose of IFN-I receptor-blocking antibody to induce a short-term blockade of the IFN-I pathway. This resulted in a transient "spike" in antigen levels, followed by rapid antigen clearance. Interestingly, short-term IFN-I blockade after coronavirus, flavivirus, rhabdovirus, or arenavirus infection induced a long-lasting enhancement of immunological memory that conferred improved protection upon subsequent reinfections. Short-term IFN-I blockade also improved the efficacy of viral vaccines. These findings demonstrate a novel mechanism by which IFN-I regulate immunological memory and provide insights for rational vaccine design., Competing Interests: Disclosures: N. Palacio and P. Penaloza-MacMaster reported that a provisional patent application was submitted (transient interferon blockade to enhance immune responses to antigens and improve vaccines). No other disclosures were reported., (© 2020 Palacio et al.)
- Published
- 2020
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19. Feeding ecology of Atlantic bluefin tuna (Thunnus thynnus) in the Gulf of Saint Lawrence, Canada.
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Varela JL, Spares AD, and Stokesbury MJW
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- Animals, Canada, Diet, Humans, Isotopes, Ecology, Tuna
- Abstract
Feeding ecology of Atlantic bluefin tuna (ABFT, Thunnus thynnus), from the Gulf of Saint Lawrence, Canada, was assessed by stomach content and stable isotope analyses. Stomachs were collected from 161 individuals averaging 249 ± 20 cm in curved fork length and 248 ± 64 in round weight. The fish were caught by commercial fishing boats using rod and reel gear during fall 2015-2017. Liver and muscle samples were taken from 133 fish for stable isotope analysis. Atlantic mackerel (Scomber scombrus) was the most abundant prey item in 2015 (%Alimentary index, %AI = 88.94), whereas in 2016 and 2017 the ABFT diet was mainly composed of Atlantic herring (Clupea harengus) (%AI = 56.73 and %AI = 77.23, respectively). PERMANOVA analysis revealed significant differences in the dietary composition between years. δ
15 N values varied between 12.3 and 15.4‰ for muscle and between 11.1 and 14.6‰ for liver. δ13 C values ranged from -19.9 to -16.5‰ for muscle and from -20.7 to -17.3‰ for liver. PERMANOVA analysis also detected inter-annual isotopic differences in both muscle and liver samples (p < 0.05). Daily rations (DR) were similar in 2015 and 2016 (DR = 1.02 ± 0.32 and DR = 1.10 ± 0.21, respectively), but higher in 2017 (DR = 1.73 ± 0.54)., (Copyright © 2020 Elsevier Ltd. All rights reserved.)- Published
- 2020
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20. Common dolphinfish, Coryphaena hippurus, spawn at their easternmost Atlantic range adjacent to the Mediterranean Sea.
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Medina A, Abascal FJ, and Varela JL
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- Animals, Atlantic Ocean, Female, Male, Mediterranean Sea, Seasons, Spain, Perciformes physiology, Reproduction, Sexual Behavior, Animal physiology
- Abstract
This study provides sound evidence of the spawning activity of common dolphinfish (Coryphaena hippurus) in the Gulf of Cadiz (southwest Spain) during summer months. Along with waters off Côte d'Ivoire, this area adjacent to the Mediterranean Sea is the easternmost Atlantic spawning ground documented for the species. All the fish analysed (5 males and 15 females) were at spawning stage, except the smallest female (61.5 cm in fork length), which might not have yet reached sexual maturation. The oceanographic conditions during the samplings were similar to those occurring during the peak spawning season in the Gulf of Mexico. The study results are consistent with recent genetic studies indicating differentiation between Mediterranean and Atlantic dolphinfish populations, with the Strait of Gibraltar representing a boundary between two distinct reproductive units. The present results may contribute to improve the understanding of the dynamics of dolphinfish population and the management of eastern Atlantic and Mediterranean stocks., (© 2020 The Fisheries Society of the British Isles.)
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- 2020
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21. Seasonal feeding patterns of Atlantic bluefin tuna (Thunnus thynnus) in the Strait of Gibraltar.
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Varela JL, Carrera I, and Medina A
- Abstract
The Strait of Gibraltar (SoG) houses a large diversity of marine species including large pelagic animals that use this area as permanent or temporary habitat. In particular, the SoG is home to a population of adult and sub-adult Atlantic bluefin tuna (Thunnus thynnus) that occurs there for most of the year. To gain further insight into the life history of this ABFT population, seasonal feeding patterns were investigated combining stomach content analysis (SCA) and stable isotopes analysis (SIA) of muscle and liver tissues. Our results reveal seasonal variations in feeding patterns, which are evidenced by a significant shift in the diet composition and the highest food consumption rates that take place in spring, prior to the spawning season. These changes in feeding habits are consistent with the varying energetic needs along the species' annual biological cycle. The present observations confirm the SoG as an important foraging ground for ABFT resident populations and may have further implications for the management of the resource., (Copyright © 2019 Elsevier Ltd. All rights reserved.)
- Published
- 2020
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22. Inter-regional variation in feeding patterns of skipjack tuna (Katsuwonus pelamis) inferred from stomach content, stable isotope and fatty acid analyses.
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Varela JL, Cañavate JP, Medina A, and Mourente G
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- Animals, Fishes, Gastrointestinal Contents, Isotopes, Feeding Behavior, Tuna
- Abstract
Foraging habits of skipjack tuna, SKJ (Katsuwonus pelamis), were investigated in three Spanish marine regions (Balearic Sea, Alboran Sea and Gulf of Cadiz) using stomach content (SCA), stable isotope (SIA), and fatty acid (FA) analyses. The three methodological approaches yielded significant differences among locations. All the studied areas appear to serve as important foraging grounds for SKJ, but the diet composition significantly varied among them. The predominant prey species in the respective locations were the North Atlantic krill, Meganyctiphanes norvegica, in the Balearic Sea, the flyingfish, Exocœtus volitans, in the Alboran Sea, and the anchovy, Engraulis encrasicolus, in the Gulf of Cadiz. Regional differences were also found in δ
13 C and δ15 N values; furthermore, the analysis of standard ellipse areas (SEAc) based on isotopic data showed that the broadest niche corresponded to SKJ from the Gulf of Cadiz, with no significant isotopic niche overlap between areas. Consistent with the SCA and stable isotope results, the FA composition varied among areas. Docosahexaenoic acid (DHA, 22:6n-3) was the most abundant FA in the SKJ muscle, showing its highest values in samples from the Gulf of Cadiz; this FA was the most effective in segregating SKJ geographical groups. In conclusion, this study provides evidence that SKJ in eastern Atlantic and western Mediterranean waters can easily adapt their diet to local prey availability. Furthermore, stable isotope signatures and FA profiles of muscle tissue prove to be reliable trophic markers that allow separation of populations occurring in different marine areas., (Copyright © 2019 Elsevier Ltd. All rights reserved.)- Published
- 2019
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23. Tumor suppression of novel anti-PD-1 antibodies mediated through CD28 costimulatory pathway.
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Fenwick C, Loredo-Varela JL, Joo V, Pellaton C, Farina A, Rajah N, Esteves-Leuenberger L, Decaillon T, Suffiotti M, Noto A, Ohmiti K, Gottardo R, Weissenhorn W, and Pantaleo G
- Subjects
- Animals, Antineoplastic Agents, Immunological therapeutic use, CD8-Positive T-Lymphocytes immunology, Epitopes immunology, Humans, Jurkat Cells, Mice, NF-kappa B metabolism, Neoplasms, Experimental therapy, Proto-Oncogene Proteins c-akt metabolism, Signal Transduction, Antineoplastic Agents, Immunological immunology, CD28 Antigens metabolism, Neoplasms, Experimental immunology, Programmed Cell Death 1 Receptor immunology
- Abstract
Classical antagonistic antibodies (Abs) targeting PD-1, such as pembrolizumab and nivolumab, act through blockade of the PD-1-PDL-1 interaction. Here, we have identified novel antagonistic anti-PD-1 Abs not blocking the PD-1-PDL-1 interaction. The nonblocking Abs recognize epitopes on PD-1 located on the opposing face of the PDL-1 interaction and overlap with a newly identified evolutionarily conserved patch. These nonblocking Abs act predominantly through the CD28 coreceptor. Importantly, a combination of blocking and nonblocking Abs synergize in the functional recovery of antigen-specific exhausted CD8 T cells. Interestingly, nonblocking anti-PD-1 Abs have equivalent antitumor activity compared with blocker Abs in two mouse tumor models, and combination therapy using both classes of Abs enhanced tumor suppression in the mouse immunogenic tumor model. The identification of the novel nonblocker anti-PD-1 Abs and their synergy with classical blocker Abs may be instrumental in potentiating immunotherapy strategies and antitumor activity., (© 2019 Fenwick et al.)
- Published
- 2019
- Full Text
- View/download PDF
24. Inhibition of mTOR Signaling and Clinical Activity of Rapamycin in Head and Neck Cancer in a Window of Opportunity Trial.
- Author
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Day TA, Shirai K, O'Brien PE, Matheus MG, Godwin K, Sood AJ, Kompelli A, Vick JA, Martin D, Vitale-Cross L, Callejas-Varela JL, Wang Z, Wu X, Harismendy O, Molinolo AA, Lippman SM, Van Waes C, Szabo E, and Gutkind JS
- Subjects
- Animals, Apoptosis, Cell Line, Tumor, Class I Phosphatidylinositol 3-Kinases genetics, Female, Gene Expression Regulation, Neoplastic drug effects, Head and Neck Neoplasms genetics, Head and Neck Neoplasms pathology, Humans, Male, Mice, Middle Aged, Neoadjuvant Therapy, Neoplasm Staging, Phosphorylation, Positron Emission Tomography Computed Tomography, Proto-Oncogene Proteins c-akt genetics, Signal Transduction drug effects, Squamous Cell Carcinoma of Head and Neck genetics, Squamous Cell Carcinoma of Head and Neck pathology, TOR Serine-Threonine Kinases antagonists & inhibitors, Exome Sequencing, Xenograft Model Antitumor Assays, Head and Neck Neoplasms drug therapy, Sirolimus administration & dosage, Squamous Cell Carcinoma of Head and Neck drug therapy, TOR Serine-Threonine Kinases genetics
- Abstract
Purpose: We studied the impact of mTOR signaling inhibition with rapamycin in head and neck squamous cell carcinoma (HNSCC) in the neoadjuvant setting. The goals were to evaluate the mTOR pathway as a therapeutic target for patients with advanced HNSCC, and the clinical safety, antitumor, and molecular activity of rapamycin administration on HNSCC., Patients and Methods: Patients with untreated stage II-IVA HNSCC received rapamycin for 21 days (day 1, 15 mg; days 2-12, 5 mg) prior to definitive treatment with surgery or chemoradiation. Treatment responses were assessed clinically and radiographically with CT and FDG-PET. Pre- and posttreatment biopsies and blood were obtained for toxicity, immune monitoring, and IHC assessment of mTOR signaling, as well as exome sequencing., Results: Sixteen patients (eight oral cavity, eight oropharyngeal) completed rapamycin and definitive treatment. Half of patients were p16 positive. One patient had a pathologic complete response and four (25%) patients met RECIST criteria for response (1 CR, 3 PR, 12 SD). Treatment was well tolerated with no grade 4 or unexpected toxicities. No significant immune suppression was observed. Downstream mTOR signaling was downregulated in tumor tissues as measured by phosphorylation of S6 ( P < 0.0001), AKT ( P < 0.0001), and 4EBP ( P = 0.0361), with a significant compensatory increase in phosphorylated ERK in most patients ( P < 0.001). Ki67 was reduced in tumor biopsies in all patients ( P = 0.013)., Conclusions: Rapamycin treatment was well tolerated, reduced mTOR signaling and tumor growth, and resulted in significant clinical responses despite the brief treatment duration, thus supporting the potential role of mTOR inhibitors in treatment regimens for HNSCC., (©2018 American Association for Cancer Research.)
- Published
- 2019
- Full Text
- View/download PDF
25. Using stable isotope analysis to assess trophic relationships between Atlantic bluefin tuna (Thunnus thynnus) and striped dolphin (Stenella coeruleoalba) in the Strait of Gibraltar.
- Author
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Varela JL, Rojo-Nieto E, Sorell JM, and Medina A
- Subjects
- Animals, Ecology, Gibraltar, Isotopes, Nutritional Status, Food Chain, Stenella physiology, Tuna physiology
- Abstract
Stable isotope analysis (δ
13 C and δ15 N from liver and muscle) was used to assess trophic relationships between Atlantic bluefin tuna (ABFT) (Thunnus thynnus) and striped dolphin (SC) (Stenella coeruleoalba) in the Strait of Gibraltar (SoG). δ15 N values from ABFT muscle and liver tissues were significantly different from those of dolphin samples, but no for δ13 C values. Diet estimation by MixSIAR models from muscle and liver revealed that ABFT fed mainly on squids (Todaropsis eblanae and Illex coindetii). The shrimp Pasiphaea sp. was estimated to be the most important prey-species in the diet of SC. Trophic positions estimated from muscle and liver isotopic data suggested that ABFT occupy a higher trophic level than SC. Estimations of isotopic niche, as measured by the standard ellipse area, indicated that ABFT show a broader trophic niche than SC; furthermore, SEAc did not show trophic overlap between both predators. The results of this study suggest that resource partitioning occurs between ABFT and SC in the SoG ecosystem., (Copyright © 2018 Elsevier Ltd. All rights reserved.)- Published
- 2018
- Full Text
- View/download PDF
26. Methylmercury in tissues of Atlantic sturgeon (Acipenser oxyrhynchus) from the Saint John River, New Brunswick, Canada.
- Author
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Mallory ML, O'Driscoll NJ, Klapstein S, Varela JL, Ceapa C, and Stokesbury MJ
- Subjects
- Animals, Canada, Female, Food Chain, Food Contamination, Liver chemistry, Male, Mercury analysis, Muscles chemistry, New Brunswick, Rivers, Fishes, Methylmercury Compounds blood
- Abstract
Environmental contamination by mercury is a concern in marine food webs, and especially for large fish. We examined methylmercury (MeHg) levels in blood, muscle and liver of 35 individual Atlantic sturgeon (Acipenser oxyrhynchus), a commercially harvested, anadromous fish eastern Canada. Females had higher blood and liver MeHg levels than males, and in some tissues there was a suggestion of higher mercury in longer fish. Collectively, sturgeon MeHg levels were far below Canadian and international guidelines for safe consumption of fish meat., (Copyright © 2017 Elsevier Ltd. All rights reserved.)
- Published
- 2018
- Full Text
- View/download PDF
27. Antigp41 membrane proximal external region antibodies and the art of using the membrane for neutralization.
- Author
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Cerutti N, Loredo-Varela JL, Caillat C, and Weissenhorn W
- Subjects
- Animals, Antibodies, Neutralizing immunology, Epitopes chemistry, Epitopes genetics, Epitopes immunology, HIV Envelope Protein gp41 genetics, HIV Infections prevention & control, HIV Infections virology, HIV-1 chemistry, HIV-1 genetics, Humans, Protein Domains, HIV Antibodies immunology, HIV Envelope Protein gp41 chemistry, HIV Envelope Protein gp41 immunology, HIV Infections immunology, HIV-1 immunology
- Abstract
Purpose of Review: We summarize the latest research on the progress to understand the neutralizing epitopes present within the membrane proximal external region (MPER) of the HIV-1 fusion protein subunit gp41., Recent Findings: The HIV-1 fusion protein subunit gp41 contains a highly conserved sequence that is essential for membrane fusion and targeted by broadly neutralizing antibodies such as 2F5, 4E10, Z13e1, and 10E8. These antibodies recognize a linear gp41 epitope with high affinity, but require additional hydrophobic sequences present in their heavy chain CDR3 for neutralization. Recent structural studies on mAbs 4E10 and 10E8 provide molecular details for specific interactions with lipids and implicate part of the transmembrane region as the relevant 10E8 epitope. Although many different approaches have been applied to engineer gp41 immunogens that can induce broadly neutralizing antibodies directed toward MPER, only modest success has yet been reported., Summary: The new structural details on the complex gp41-lipidic epitope will spur new approaches to design gp41-MPER immunogens that might induce broadly neutralizing antibody responses.
- Published
- 2017
- Full Text
- View/download PDF
28. Spawning behaviour and post-spawning migration patterns of atlantic bluefin tuna (Thunnus thynnus) ascertained from satellite archival tags.
- Author
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Aranda G, Abascal FJ, Varela JL, and Medina A
- Subjects
- Animals, Atlantic Ocean, Environment, Female, Male, Satellite Communications, Seasons, Spain, Animal Migration, Behavior, Animal, Remote Sensing Technology, Tuna physiology
- Abstract
Spawning behaviour of Atlantic bluefin tuna (Thunnus thynnus) was investigated using electronic satellite tags deployed in the western Mediterranean spawning ground, around the Balearic Islands (years 2009-2011). All the fish were tagged underwater and released within schools. In general, the fish tagged in the same year/school displayed common migratory trends. Following extended residency around the Balearic Islands, most tagged tuna crossed the Strait of Gibraltar heading for the North Atlantic. Discrepancies between the migratory tracks reconstructed from this and previous electronic tagging studies suggest that the bluefin tuna Mediterranean population may comprise distinct units exhibiting differing migratory behaviours. The diving behaviour varied between oceanic regions throughout the migratory pathways, the shallowest distribution taking place in the spawning ground and the deepest at the Strait of Gibraltar. A unique diving pattern was found on the majority of nights while the fish stayed at the spawning ground; it consisted of frequent and brief oscillatory movements up and down through the mixed layer, resulting in thermal profiles characterized by oscillations about the thermocline. Such a pattern is believed to reflect recent courtship and spawning activity. Reproductive parameters inferred from the analysis of vertical profiles are consistent with those estimated in previous studies based on biological samples.
- Published
- 2013
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- View/download PDF
29. Metabolic and osmoregulatory changes and cell proliferation in gilthead sea bream (Sparus aurata) exposed to cadmium.
- Author
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Garcia-Santos S, Vargas-Chacoff L, Ruiz-Jarabo I, Varela JL, Mancera JM, Fontaínhas-Fernandes A, and Wilson JM
- Subjects
- Animals, Cadmium administration & dosage, Caspase 3 metabolism, Dose-Response Relationship, Drug, Gills drug effects, Gills metabolism, HSP70 Heat-Shock Proteins metabolism, HSP90 Heat-Shock Proteins metabolism, Kidney drug effects, Kidney metabolism, Metallothionein metabolism, Sea Bream metabolism, Sodium-Potassium-Exchanging ATPase metabolism, Water Pollutants, Chemical administration & dosage, Cadmium toxicity, Cell Proliferation drug effects, Sea Bream physiology, Water Pollutants, Chemical toxicity, Water-Electrolyte Balance drug effects
- Abstract
The impact of cadmium on metabolism and osmoregulation was assessed in gilthead sea bream (Sparus aurata). Seawater acclimated fish were injected intraperitoneally with a sublethal dose of cadmium (1.25 mg Cd/kg body wt). After 7 days, half of the injected fish were sampled. The remaining fish were transferred to hypersaline water and sampled 4 days later. Gill and kidney Na(+)/K(+)-ATPase activities, plasma levels of cortisol, several metabolites and osmolytes, as well as osmolality were measured. Hepatosomatic index and condition factor were calculated. The expression levels of Na(+)/K(+)-ATPase, heat shock proteins (HSP70, HSP90) and proliferating cell nuclear antigen was assessed by western blotting. Cadmium treatment adversely affected the Na(+)/K(+)-ATPase activity, although, there was no perturbation in ion homeostasis and the animals were not compromised following transfer to hypersaline water. Increased cell proliferation and Hsp90 expression likely contributed to the attenuation of the deleterious effects of cadmium exposure., (Copyright © 2010 Elsevier Inc. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
30. [Spondyloepiphyseal dysplasia of a pseudoachondroplastic type].
- Author
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Perianes J, Peláez JL, Varela JL, Calderín FM, and Calleja JL
- Subjects
- Adolescent, Diagnosis, Differential, Female, Humans, Achondroplasia diagnosis, Mucopolysaccharidosis IV diagnosis
- Published
- 1965
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