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1.
Trop Anim Health Prod ; 55(4): 261, 2023 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-37405611

RESUMEN

This study evaluated the body condition score (BCS) at calving and breed (B) effects on milk composition, yield, performance, physiological parameters, hemogram, blood metabolites, and urinary metabolites in the transition and early lactation periods of Mediterranean (MED) and Murrah (MUR) buffaloes. Twenty MED and fifteen MUR buffaloes were distributed into four experimental treatments, in a completely randomized design, considering their racial groups and BCS (LBCS = low; HBCS = high): LBCS MED (N = 9); HBCS MED (N = 11); LBCS MUR (N = 8); HBCS MUR (N = 7). Animals were monitored during the last 21 days of gestation and first 56 days postpartum and kept under the same management and feeding conditions. During data collection, milk composition, yield, performance, physiological parameters, hemogram, blood metabolites, and urinary metabolites were evaluated. Higher milk production and fat-corrected milk were observed in MED than MUR buffaloes. Breed effects were observed on body weight, rectal temperature, glucose, urea, calcium (Ca) concentrations, and BCS effects on total protein, albumin, urea, and Ca. There were BCS effects on hematocrit, neutrophils, eosinophils, and interactions between B × BCS for lymphocytes and platelets. There were breed effects on urinary concentrations of chlorine, uric acid, and interactions between weight (W) × B on chlorine and urea. The MED buffaloes can be considered the most prepared to undergo physiological changes, including the BCS value at calving, indicating higher physiological health. Besides, this study demonstrates more considerable preparation for the calving, regardless of the body condition score at calving.


Asunto(s)
Bison , Búfalos , Femenino , Animales , Humanos , Cloro/metabolismo , Lactancia/fisiología , Leche/metabolismo , Periodo Posparto/fisiología , Grupos Raciales , Metaboloma
2.
Eur Ann Allergy Clin Immunol ; 54(4): 168-174, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33944542

RESUMEN

Summary: Background. Acute urticaria is a common condition in the pediatric emergency department (ED) and no data is available in Portugal. Objective. We aimed to characterize the prevalence, etiology and management of acute urticaria in children presenting at an ED of a portuguese central hospital and report the follow-up investigation when drug or food allergy was suspected.Methods. Retrospective study of clinical records from children admitted to the ED with acute urticaria during one year period. Results. 250 children were included, mean age of 7.4 ± 4.9 years (0-17 years). The most frequently suspected etiological factors were infections (22%), foods (12%), insect bites (9%) and drugs (8%), of which, upper respiratory tract infections, seafood and ß-lactam antibiotics were the most frequent. In 44% of cases, the etiology of urticaria was not determined. After ED discharge, of the 50 patients with suggestive drug or food allergy, only 48% were sent to allergological workup and the allergy confirmed in 6 of them (2.4% of the 250 children). Conclusions. These data suggest that allergy is not the main trigger of acute urticaria in ED children, but when suspected, reference to an allergy department to complete allergological workup was insufficient.


Asunto(s)
Hipersensibilidad a los Alimentos , Urticaria , Niño , Preescolar , Servicio de Urgencia en Hospital , Hipersensibilidad a los Alimentos/diagnóstico , Hipersensibilidad a los Alimentos/epidemiología , Hipersensibilidad a los Alimentos/terapia , Hospitales , Humanos , Derivación y Consulta , Estudios Retrospectivos , Urticaria/diagnóstico , Urticaria/epidemiología , Urticaria/terapia
3.
Ecotoxicol Environ Saf ; 172: 348-355, 2019 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-30731265

RESUMEN

Predictions of the International Panel for Climate Changes on sea level rise foresee that the number of coastal regions impacted with salinization will increase in a near future. The present work intended to evaluate the sensitivity to salinization of two freshwater vertebrate species (the frog Pelophylax perezi and the fish Lepomis gibbosus) and their ability to acclimate to this stressor. For this, three specific objectives were targeted: (i) to assess if NaCl may be used as a safe surrogate for risk assessment of seawater (SW) intrusion for freshwater vertebrates; (ii) to evaluate the sensitivity of two freshwater vertebrate models to increased salinity (both due to NaCl or SW); (iii) to determine the capacity of the studied species to acclimate to low levels of salinization. To assess specific objectives (i) and (ii), organisms were exposed to serial concentrations of NaCl or SW dilutions. To assess the capacity of acclimation of both species to salinization, organisms were exposed to low serial concentrations of NaCl during the embryonic development or for a period of two months, respectively, and their sensitivity to NaCl was re-evaluated after this period. Results showed that fish juveniles were more tolerant (96-h LC50 of 21.3 mS cm-1 for NaCl and 23.6 mS cm-1 for SW) than frog embryos (96-h LC50 of 10.7 mS cm-1 for NaCl and 10.7 mS cm-1 for SW) and tadpoles (96-h LC50 of 19.4 mS cm-1 for NaCl and 8.72 mS cm-1 for SW). The fish was able to cope with conductivities of almost one third of SW conductivity, while effect conductivities computed for the amphibian were much lower than SW conductivity (≈ 52 mS cm-1). The two-fold difference between the sensitivity of the two tested species reinforces the idea that ecological risk assessment for amphibians based on fish toxicity data may underestimate the risk to the former. Acclimation to low levels of salinity caused an increase in tolerance to salinization in P. perezi tadpoles but not in fish.


Asunto(s)
Aclimatación , Perciformes/fisiología , Ranidae/fisiología , Salinidad , Tolerancia a la Sal , Animales , Agua Dulce/química , Larva/fisiología , Agua de Mar/química , Cloruro de Sodio/análisis , Estrés Fisiológico
4.
Eur Ann Allergy Clin Immunol ; 50(3): 141-144, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29384119

RESUMEN

Summary: Aquagenic urticaria (AU) is a rare form of chronic inducible urticaria elicited by water at any temperature. We describe the case of a 25-year-old atopic woman who presented to our unit with a 4-year history of recurrent urticarial rashes, highly pruritic, confined to the neck and lower part of the face, occurring solely on contact with sea water. The lesions were reproduced by challenge tests with aqueous 3.5% NaCl and other hypertonic aqueous solutions but not with 20% glucose neither tap water. Our case supports the existence of a distinct salt-dependent subtype of aquagenic urticaria (SDAU), which seems to be triggered mostly by sea bathing, affects young women and has a characteristic localization on the inferior facial contours and neck. To the best of our knowledge, only eight cases of SDAU have been reported in the literature.


Asunto(s)
Hipersensibilidad Inmediata/diagnóstico , Agua de Mar/efectos adversos , Urticaria/diagnóstico , Adulto , Femenino , Humanos , Hipersensibilidad Inmediata/inmunología , Rinitis Alérgica/complicaciones , Cloruro de Sodio , Urticaria/inmunología , Urticaria Crónica Inducible
6.
Earth Planets Space ; 68(1): 119, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27656102

RESUMEN

Heliospheric modulation of galactic cosmic rays links solar cycle activity with neutron monitor count rate on earth. A less direct relation holds between neutron monitor count rate and atmospheric electric field because different atmospheric processes, including fluctuations in the ionosphere, are involved. Although a full quantitative model is still lacking, this link is supported by solid statistical evidence. Thus, a connection between the solar cycle activity and atmospheric electric field is expected. To gain a deeper insight into these relations, sunspot area (NOAA, USA), neutron monitor count rate (Climax, Colorado, USA), and atmospheric electric field (Lisbon, Portugal) are presented here in a phase space representation. The period considered covers two solar cycles (21, 22) and extends from 1978 to 1990. Two solar maxima were observed in this dataset, one in 1979 and another in 1989, as well as one solar minimum in 1986. Two main observations of the present study were: (1) similar short-term topological features of the phase space representations of the three variables, (2) a long-term phase space radius synchronization between the solar cycle activity, neutron monitor count rate, and potential gradient (confirmed by absolute correlation values above ~0.8). Finally, the methodology proposed here can be used for obtaining the relations between other atmospheric parameters (e.g., solar radiation) and solar cycle activity.

9.
Ecotoxicol Environ Saf ; 115: 234-42, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25723133

RESUMEN

Olive mill wastewater (OMW) still is a major environmental problem due to its high chemical oxygen demand (COD) and total phenolic content (TPC), contributing for the high toxicity and recalcitrant nature. Several attempts have been made for developing more efficient treatment processes, but no chemical or biological approaches were found to be totally effective, especially in terms of toxicity reduction. In this context, the main purpose of this study was to investigate the treatability of OMW by the combination of photocatalytic oxidation, using two nanomaterials as catalysts (TiO2 and Fe2O3), with biological degradation by fungi (Pleurotus sajor caju and Phanerochaete chrysosporium). Photocatalytic oxidation was carried out using different systems, nano-TiO2/UV, nano-Fe2O3/UV, nano-TiO2/H2O2/UV and nano-Fe2O3/H2O2/UV. The effectiveness of the treatment was assessed through color (465nm), aromatics (270nm), COD and TPC reductions, as well as by the decrease in toxicity using the bacterium Vibrio fischeri. The chemical treatment with the system nano-TiO2/H2O2/UV promoted 43%, 14%, 38% and 31% reductions in color, aromatics content, COD and TPC, respectively. However no toxicity reduction was observed. The combination with a biological treatment increased the reduction of COD and TPC as well as a reduction in toxicity. The treatment with P. chrysosporium promoted the highest reduction in toxicity, but P. sajor caju was responsible for the best reduction in COD and TPC. However, the biological treatment was more effective when no hydrogen peroxide was used in the pre-treatment.


Asunto(s)
Hongos/metabolismo , Residuos Industriales , Nanoestructuras/química , Aceites de Plantas , Administración de Residuos/métodos , Aguas Residuales , Catálisis , Compuestos Férricos/química , Peróxido de Hidrógeno/química , Residuos Industriales/análisis , Aceite de Oliva , Oxidación-Reducción , Phanerochaete/metabolismo , Fenoles/análisis , Fotólisis , Aceites de Plantas/química , Pleurotus/metabolismo , Titanio/química , Aguas Residuales/química
10.
Aquat Toxicol ; 262: 106664, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37639824

RESUMEN

Wildfires have emerged as a global ecological concern due to their wide-ranging off-site effects. One particular consequence is the adverse impact on aquatic environments, as wildfires are acknowledged as a significant source of aquatic contamination through ash runoffs containing toxic compounds. Yet, amphibian response to this source of contamination remains largely undocumented. This study assessed how ash runoffs from Eucalyptus sp. and Pinus sp. affect early aquatic life-stages of Xenopus laevis. Embryos and tadpoles were exposed, respectively, for 96 h and 14 days to serial concentrations (26.9% - 100%) of aqueous extracts of ashes (AEAs; 10 gL-1) composed of eucalypt (ELS) and pine (PLS) ashes. Mortality and development were monitored, and biometric data (snout-to-vent, tail and total length, and weight) measured. Sub-individual endpoints regarding oxidative stress (catalase-CAT; total glutathione-TG; lipid peroxidation-TBARS), neurotoxicity (acetylcholinesterase-AChE), transformation metabolism (glutathione-S-transferase-GST) and energetic metabolism (carbohydrate, lipid and protein content and O2 consumption), were also measured. The two AEAs induced no significant lethal effects on embryos or tadpoles. However, in general, AEAs caused a developmental delay in both life stages. Effects of AEAs on biometric endpoint were only reported for tadpoles, which showed a decreased body length (snout-to-vent, tail and total) and weight (embryos were not weighed), with PLS exerting higher effect than ELS. As for the sub-individual endpoints, embryos showed mostly no alterations on the activity of the monitored parameters, except for PLS, which reduced embryos' carbohydrate content (at ≥59.2%) and increased O2 consumption (at ≥35.0%). Regarding tadpoles, AEA exposure decreased the activity of CAT and GST (at ≥26.0%) and decreased carbohydrate (at ≥26.0%) and lipid (at ≥45.5%), whereas oxygen consumption increased (at ≥26.0%) only on PLS. Overall, the tested AEAs differentially affected amphibians across life-stages, indicating that plant coverage might affect ash toxicity.


Asunto(s)
Contaminantes Químicos del Agua , Incendios Forestales , Animales , Xenopus laevis , Acetilcolinesterasa , Contaminantes Químicos del Agua/toxicidad , Glutatión , Glutatión Transferasa , Lípidos
11.
Nutr Metab Cardiovasc Dis ; 22(10): 849-55, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21703833

RESUMEN

BACKGROUND AND AIMS: Modulation of cholesterol absorption is potentially an effective way of lowering blood cholesterol levels and decreasing inherent cardiovascular risk in the general population. It is well established that cholesterol absorption efficiency can be modified by the intake of foods enriched with gram-doses of phytosterols, but little is known about the effects of phytosterols in the usual diet, even though moderate doses have been reported to affect whole-body cholesterol metabolism. A way to indirectly measure cholesterol synthesis and absorption rates is by quantification of serum non-cholesterol sterols. The aim of this study was to investigate the role of naturally occurring phytosterol intake on cholesterol absorption and serum cholesterol concentrations in a Spanish free-living population. METHODS AND RESULTS: A total of 85 healthy volunteers were studied regarding their dietary habits (using a validated food frequency questionnaire), lipid profile and surrogate markers of cholesterol metabolism. Subjects were classified into tertiles of total phytosterol intake, and differences in lipid profile and markers of cholesterol metabolism were assessed by multivariate linear regression models adjusted for various confounders. The estimated daily intake of phytosterols and cholesterol was 489 (median) and 513 (mean) mg, respectively. Both serum low-density lipoprotein (LDL)-cholesterol concentration and sitosterol-to-cholesterol ratio adjusted by sitosterol intake (a surrogate marker of intestinal cholesterol absorption) decreased significantly (p < 0.05, both) across tertiles of phytosterol intake. CONCLUSION: Moderate doses of phytosterols in the habitual diet might have a protective effect on the lipid profile via decreasing cholesterol absorption.


Asunto(s)
Anticolesterolemiantes/administración & dosificación , Conducta Alimentaria , Metabolismo de los Lípidos/efectos de los fármacos , Fitosteroles/administración & dosificación , Adolescente , Adulto , Anciano , Enfermedades Cardiovasculares/prevención & control , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Estudios Transversales , Femenino , Humanos , Estilo de Vida , Modelos Lineales , Masculino , Persona de Mediana Edad , Análisis Multivariante , Evaluación Nutricional , Encuestas y Cuestionarios , Adulto Joven
12.
Ecotoxicology ; 21(3): 637-48, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22314390

RESUMEN

The present work aimed at evaluating the toxicity and genotoxicity of two organic (vesicles composed of sodium dodecyl sulphate/didodecyl dimethylammonium bromide-SDS/DDAB and of monoolein and sodium oelate-Mo/NaO) and four inorganic (titanium oxide-TiO2, silicon titanium-TiSiO4, Lumidot-CdSe/ZnS, and gold nanorods) nanoparticles (NP), suspended in two aqueous media (Milli Q water and American Society for Testing and Materials (ASTM) hardwater), to the bacteria Vibrio fischeri (Microtox test) and Salmonella typhimurium-his⁻ (Ames test with strains TA98 and TA100). Aiming a better understanding of these biological responses physical and chemical characterization of the studied NP suspensions was carried out. Results denoted a high aggregation state of the NP in the aqueous suspensions, with the exception of SDS/DDAB and Mo/NaO vesicles, and of nanogold suspended in Milli Q water. This higher aggregation was consistent with the low values of zeta potential, revealing the instability of the suspensions. Regarding toxicity data, except for nano TiO2, the tested NP significantly inhibited bioluminescence of V. fischeri. Genotoxic effects were only induced by SDS/DDAB and TiO2 for the strain TA98. A wide range of toxicity responses was observed for the six tested NP, differing by more than 5 orders of magnitude, and suggesting different modes of action of the tested NP.


Asunto(s)
Aliivibrio fischeri/efectos de los fármacos , Compuestos Inorgánicos/toxicidad , Nanopartículas del Metal/toxicidad , Mutágenos/toxicidad , Compuestos Orgánicos/toxicidad , Salmonella typhimurium/efectos de los fármacos , Aliivibrio fischeri/genética , Difusión , Electroquímica/métodos , Glicéridos/toxicidad , Compuestos Inorgánicos/clasificación , Luminiscencia , Mediciones Luminiscentes , Nanopartículas del Metal/clasificación , Pruebas de Mutagenicidad , Mutágenos/clasificación , Ácido Oléico/toxicidad , Compuestos Orgánicos/clasificación , Compuestos de Amonio Cuaternario/toxicidad , Salmonella typhimurium/genética , Dodecil Sulfato de Sodio/toxicidad , Tensoactivos/toxicidad
13.
Sci Total Environ ; 806(Pt 1): 150491, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34844312

RESUMEN

Polymethylmethacrylate (PMMA) production has increased almost 20% over the last years. With its release into the aquatic environment, its breakdown or degradation to nano dimensions (nanoplastics-NPLs) due to biological and physical/mechanical action is, theoretically, anticipated. The occurrence of PMMA-NPLs in aquatic ecosystems may thus cause adverse effects particularly to early life stages of amphibians, which may be in contact with PMMA-NPLs suspended in the water column or deposited in upper layers of the sediments. Accordingly, this work aimed at assessing the effects of PMMA-NPLs to aquatic early life stages of the model anuran species Xenopus laevis. To attain this objective, two types of toxicity assays were carried out by exposing embryos [Nieuwkoop and Faber (NF) stage 8-11] or tadpoles (NF 45) to three concentrations of PMMA-NPLs (1, 100 and 1000 µg/L): i) 96-h embryo teratogenicity assay, where survival, malformation, and total body length (BL) of embryos were assessed; and ii) 48-h feeding rate assay, where survival, feeding (FR), malformations and growth rates (body weight-BW and BL) of tadpoles were evaluated. PMMA-NPLs exposure had no significant effects on mortality, malformations of X. laevis embryos but BL was lower at 1000 µg PMMA-NPLs/L. In tadpoles, no effects on survival or FR were observed after exposure to PMMA-NPLs, but significant changes occured in BW and BL. Moreover, anatomical changes in the abdominal region (externalization of the gut) were observed in 62.5% of the tadpoles exposed to 1000 µg PMMA-NPLs/L. Despite the lack of knowledge regarding the environmental levels of NPLs, it is expected that sediments constitute a sink for these contaminants, where they can become available for organisms that, like tadpoles, feed on the organic matter at the surface of sediments. Considering the continuous release and subsequent accumulation of PMMA, the malformations obtained in the feeding assays suggest that, in the future, these nano-polymers may constitute a risk for aquatic life stages of amphibians.


Asunto(s)
Microplásticos , Polimetil Metacrilato , Animales , Ecosistema , Larva , Polimetil Metacrilato/toxicidad , Xenopus laevis
14.
Sci Total Environ ; 823: 153745, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35150685

RESUMEN

The health effects of the particulate matter (PM) depend not only on its aerodynamic diameter (AD) and chemical composition, but also on the time activity pattern of the individuals and on their age. The main objective of this work was to assess the exposure of children to aerosol particles by using personal instruments, to study the particle size and composition of the inhaled PM, and to estimate their transport and deposition into the human respiratory tract (HRT). The average daily PM2.5 exposure was 19 µg/m3 and the size fractions with the greatest contribution to PM2.5 concentrations were 1 < AD <2.5 µm and AD <0.25 µm. Results indicated a contribution of 9% from the mineral aerosol, 7.2% from anthropogenic sulphate, 6.7% from black carbon and 5% from anthropogenic trace elements to the daily exposure to PM2.5. The levels of mineral and marine elements increased with increasing particle size, while anthropogenic elements were present in higher concentrations in the finest particles. Particle size has been shown to influence the variability of daily dose deposited between the extrathoracic and alveolar-interstitial zones. On average, 3% of the PM deposited in the bronchial region, whereas 5% to 8% were found in the bronchiolar region. The level of physical activity had a significant contribution to the total daily dose.


Asunto(s)
Contaminantes Atmosféricos , Oligoelementos , Aerosoles , Contaminantes Atmosféricos/análisis , Niño , Monitoreo del Ambiente , Humanos , Tamaño de la Partícula , Material Particulado/análisis
15.
Genet Mol Res ; 10(3): 1910-22, 2011 Aug 30.
Artículo en Inglés | MEDLINE | ID: mdl-21948753

RESUMEN

The wood stork (Mycteria americana) is a colonial wading bird that inhabits the Neotropical region from the southeastern United States (US) to northern Argentina. The species is considered to be endangered in the US due to degradation of its foraging and breeding habitat. In other parts of its range, such as in the Brazilian Pantanal region, breeding populations of this species appear to be stable. We compared the levels of genetic variability and population structuring of the US and the Pantanal breeding populations using mitochondrial DNA (mtDNA) control region sequences. Twenty-seven haplotypes were identified among 88 wood stork samples collected from eight breeding colonies in the US and eight in the Pantanal. Patterns indicative of heteroplasmy were observed in 35.3% of the mtDNA sequences that were examined. Significantly higher levels of haplotype diversity were observed in the Pantanal samples compared to those from the US, suggesting that during the last century, demographic declines or a recent evolutionary bottleneck reduced the levels of mtDNA variability of the US population. Analyses of genetic structuring revealed non-significant genetic differentiation between these regions, indicating that either the populations were only recently separated or that gene flow continues to occur at low levels. Haplotype network analysis indicated low current levels of gene flow between populations that were closely related in the past.


Asunto(s)
Aves/genética , ADN Mitocondrial/análisis , ADN Mitocondrial/genética , Mitocondrias/genética , Animales , Secuencia de Bases , Brasil , Especies en Peligro de Extinción , Evolución Molecular , Variación Genética , Genotipo , Haplotipos , Análisis de Secuencia de ADN , Estados Unidos
16.
J Hazard Mater ; 413: 125443, 2021 07 05.
Artículo en Inglés | MEDLINE | ID: mdl-33930964

RESUMEN

The environmental effects of nanoplastics-NPLs have been addressed mainly through short-term exposures to a few types of polymers, neglecting other NPLs that are economically relevant like polymethylmethacrylate - PMMA. This work aimed to assess long-term effects of PMMA-NPLs on the marine primary consumer Brachionus plicatilis, evaluating the influence of different exposure routes (waterborne, foodborne and both) and food items (Nannochloropsis gaditana and Tetraselmis chuii). Rotifers were 21 days exposed to: a) control, with clean medium and food-CTR; b) contaminated medium (8.1 mg PMMA-NPLs/L) and clean algae-MC; c) clean medium and contaminated algae (pre-incubated for 96 h on 8.1 mg PMMA-NPLs/L)-AC; and, d) contaminated medium and algae-MC/AC. Mortality (lx), total number of organisms (TN), fecundity (mx), populational growth rate (r), generational time (gt), and feeding rates were assessed. Effects on r and mx were found after 21 days. Organisms from AC had higher r than MC. MC/AC organisms performed better than control in all endpoints. Overall organisms fed with N. gaditana had higher TN, mx and r than those fed with T. chuii. In the AC treatments, rotifers fed with N. gaditana had higher mx. Results highlight that exposure route and food type may modulate NPLs' effects, supporting the need for standardization of assays.


Asunto(s)
Chlorophyta , Rotíferos , Contaminantes Químicos del Agua , Animales , Alimentos , Polimetil Metacrilato/toxicidad
17.
J Hazard Mater ; 402: 123773, 2021 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-33254784

RESUMEN

The current understanding of nanoplastics (NPLs) toxicity to freshwater biota, especially the potential toxic effects of polymethylmethacrylate (PMMA), remains limited. Thus, the present work intended to add knowledge about the ecotoxicity of ∼40 nm PMMA-NPLs focusing on lethality, morphology, feeding and regeneration capacity of the freshwater cnidarian Hydra viridissima, after an exposure period of 96 h. Results showed that high concentrations of PMMA-NPLs can impair the survival of H. viridissima, with an estimated 96 h-LC50 of 84.0 mg PMMA-NPLs/L. Several morphological alterations were detected at concentrations below 40 PMMA-NPLs mg/L, namely partial or total loss of tentacles, which, however, did not induce significant alterations on the feeding rates. Morphological alterations not previously reported in the literature were also found after the 96 h exposure, such as double or elbow-like tentacles. Exposure to 40 mg PMMA-NPLs/L significantly impacted hydra regeneration, with organisms exposed to PMMA-NPLs presenting significant slower regeneration rates comparatively to controls, but with no impacts on the feeding rates. Overall, this work highlights the need to assess the effects of NPLs in freshwater biota. Hydra viridissima species was sensitive in a wide range of endpoints showing its value as a biological model to study the effects of small plastic particles.


Asunto(s)
Cnidarios , Hydra , Contaminantes Químicos del Agua , Animales , Agua Dulce , Microplásticos , Polimetil Metacrilato/toxicidad
18.
Chemosphere ; 264(Pt 1): 128403, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33007568

RESUMEN

Natural populations are commonly exposed to sequential pulses of contaminants. Accordingly, this study aimed at testing the existence of an association between the tolerance to lethal levels of copper (Cu) and the survival recovery ability from pulsed partially lethal copper exposures in six clonal lineages of Daphnia longispina. It was hypothesized that the most tolerant genotypes would be the ones exhibiting a faster survival recovery from a pulsed contaminant exposure. For each clonal lineage, the intensity of pulses corresponded to the respective concentration of Cu causing 30% of mortality after 24h of exposure (LC30,24h). The initial hypothesis was not corroborated: obtained results showed no association between survival recovery and lethal tolerance to Cu. Nevertheless, some patterns could be detected. Firstly, the most sensitive lineages to lethal levels of copper revealed a faster survival recovery from a first Cu pulse comparatively to the most tolerant ones, though they were the most sensitive to a second pulse exposure. Secondly, the most tolerant lineages, though being more tolerant to a second exposure, exhibited the lowest survival recovery capacity after exposure to a first pulse of Cu. However, differences in the survival recovery capacity of the six clonal lineages after the exposure to the two pulses of Cu were not observed. Increasing the duration of the recovery period from 24h to 72h did not significantly alter mortality rates, except for the most sensitive and most tolerant clonal lineages. The results here obtained suggests that standard lethality assays may sub-estimate the toxicity of chemicals under realistic exposure scenarios, since sequential pulses are not infrequent in natural conditions.


Asunto(s)
Daphnia , Contaminantes Químicos del Agua , Animales , Bioensayo , Cobre/toxicidad , Genotipo , Contaminantes Químicos del Agua/toxicidad
19.
Biochem Biophys Rep ; 26: 100992, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-33898765

RESUMEN

This study aimed to assess the effect of supplementation with omega-3 in Wistar rats exposed to ionizing radiation in a dose of 18 Gy on the cortical electrical activity, using mathematical methods such as the power spectrum (PS) and the detrended fluctuation analysis (DFA) in the evaluation of the electrocorticogram (ECoG) record. The PS analysis showed that in non-irradiated animals but supplemented with omega-3 there was a decrease in the power of the beta rhythm, while the DFA applied to different frequency ranges of the ECoG showed a significant increase in the long-range correlation only for the theta wave when compared with non-supplemented animals. In the evaluation of the radiation effect through the PS, an increase in the power of the theta rhythm was observed in both groups (non-supplemented and supplemented animals) only when they were evaluated one week after irradiation. The DFA method also showed difference in this wave. The PS and DFA methods applied to the ECoG record allowed a quantitative analysis of the cortical electrical activity in rats in response to the omega-3 effects, ionizing radiation, or both.

20.
Environ Monit Assess ; 161(1-4): 237-45, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19184479

RESUMEN

Two populations of the European bee-eater were studied, one living at a reference site and the other at a metal mining site. The concentration of arsenic and 11 metals (Al, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, and Zn) was measured in feathers and regurgitated pellets collected at both sites. Cadmium, chromium, mercury, nickel, and lead were at least twofold higher in feathers of birds from the contaminated site than in the reference site, suggesting that this population was exposed to higher metal levels. Similarly, levels of aluminum, arsenic, cadmium, cobalt, chromium, iron, and lead were also at least twofold higher in pellets from the contaminated area. The obtained results suggested that the impacted population of Merops apiaster is at risk due to the exposure to some metals.


Asunto(s)
Arsénico/metabolismo , Aves/metabolismo , Metales/metabolismo , Minería , Aluminio/metabolismo , Animales , Cadmio/metabolismo , Cromo/metabolismo , Cobalto/metabolismo , Plumas/metabolismo , Geografía , Hierro/metabolismo , Plomo/metabolismo , Níquel/metabolismo , Portugal , Zinc/metabolismo
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