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1.
Sci Total Environ ; 806(Pt 1): 150491, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-34844312

RESUMO

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.


Assuntos
Microplásticos , Polimetil Metacrilato , Animais , Ecossistema , Larva , Polimetil Metacrilato/toxicidade , Xenopus laevis
2.
J Hazard Mater ; 413: 125443, 2021 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-33930964

RESUMO

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.


Assuntos
Clorófitas , Rotíferos , Poluentes Químicos da Água , Animais , Alimentos , Polimetil Metacrilato/toxicidade
3.
Food Funct ; 12(6): 2631-2643, 2021 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-33645604

RESUMO

Prostate cancer (PCa) is one of the most common cancers in men, with a huge impact on their health. The use of Castanea sativa Mill. flowers (CFs) in beverages has been reported, through ancestral claims, as having health benefits. In vitro research has evidenced the properties of CFs, such as antitumor and antioxidant activities. This study aimed to evaluate the effects of CF extract in an animal model of PCa. Forty male Wistar Unilever rats were randomly assigned to four groups: control, induced, control + CF, and induced + CF groups. Animals from the induced groups were exposed to a multistep protocol for PCa induction. The CF extract, rich in trigalloyl-HHDP-glucoside and obtained via decoction, was administered to the CF groups in drinking water (3 mg per animal per day) for 49 weeks. Animals were sacrificed at 61 weeks of age. Regarding the effects of CFs on dorsolateral prostate tumorigenesis, no significant differences were observed between the induced and induced + CF groups. However, animals exposed to the CF extract showed fewer inflammation areas on the dorsolateral prostate lobe than those not exposed to CF. Moreover, the CF extract alleviated the hepatic oxidative stress associated with the multistep protocol, resulting in lower levels of lipid peroxidation. These results suggest that CF extract has antioxidant and anti-inflammatory properties.


Assuntos
Antineoplásicos/farmacologia , Fagaceae/química , Flores/química , Extratos Vegetais/farmacologia , Neoplasias da Próstata/metabolismo , Animais , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Neoplasias Experimentais , Estresse Oxidativo/efeitos dos fármacos , Próstata/efeitos dos fármacos , Próstata/metabolismo , Próstata/patologia , Neoplasias da Próstata/patologia , Ratos , Ratos Wistar
4.
J Hazard Mater ; 409: 124966, 2021 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-33418294

RESUMO

The hydrophobic substitution (HS) of cationic cellulose derivatives may be tuned, promoting their efficiency. This work studied the influence of HS on the acute ecotoxicity of quaternized hydroxyethyl cellulose polymers (SL) to aquatic biota. The ecotoxicity of four SL with different HS (SL-5, SL-30, SL-60, SL-100) was assessed for seven species: Vibrio fischeri, Raphidocelis subcapitata, Chlorella vulgaris, Daphnia magna, Brachionus calyciflorus, Heterocypris incongruens, and Danio rerio. The computed median effective concentrations were used to derive hazard concentrations, by using species sensitive distribution curves. All SL suspensions were characterized for particle size, zeta potential and rheological properties. Results indicated instability of the SL in suspension due to their relatively low zeta potential. Raphidocelis subcapitata, C. vulgaris and B. calyciflorus were the most sensitive to the four SL, suggesting that exposure to these compounds may imbalance the lowest trophic levels. Also, HS influenced the toxicity of SL, with the lowest HS (SL-5) revealing lower ecotoxicity. The maximum acceptable concentrations were 14.0, 2.9, 3.9 and 1.4 mg L-1 for SL-5, SL-30, SL-60, and SL-100, respectively. Accordingly, SL-5 is suggested as the eco-friendliest and is recommended to be used in the production of care products, in detriment of the other three tested variants.


Assuntos
Chlorella vulgaris , Poluentes Químicos da Água , Aliivibrio fischeri , Animais , Organismos Aquáticos , Biota , Celulose/toxicidade , Daphnia , Polímeros/toxicidade , Poluentes Químicos da Água/toxicidade
5.
J Hazard Mater ; 402: 123773, 2021 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-33254784

RESUMO

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.


Assuntos
Cnidários , Hydra , Poluentes Químicos da Água , Animais , Água Doce , Microplásticos , Polimetil Metacrilato/toxicidade
6.
Chemosphere ; 264(Pt 1): 128403, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33007568

RESUMO

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.


Assuntos
Daphnia , Poluentes Químicos da Água , Animais , Bioensaio , Cobre/toxicidade , Genótipo , Poluentes Químicos da Água/toxicidade
7.
Environ Pollut ; 258: 113805, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31883492

RESUMO

Ecological risk assessment associated with seawater intrusions has been supported on the determination of lethal/sublethal effects following standard protocols that force exposure neglecting the ability of mobile organisms to spatially avoid salinized environments. Thus, this work aimed at assessing active emigration from climate change-caused seawater intrusion into freshwater habitats. To specific objectives were delineated: first, to compute median 12-h avoidance conductivities (AC50,12h) for freshwater species, and second, to compare it with literature data (LC50,48 or 96h, EC50,6 or 21d) to assess the relevance of the inclusion of stressor-driven emigration into risk assessment frameworks. Four standard test species, representing a broad range of ecological niches - Daphnia magna, Heterocypris incongruens, Danio rerio and Xenopus laevis - were selected. The salt NaCl was used as a surrogate of natural seawater to create the saline gradient, which was established in a 7-compartment system. At each specific LC50, 48 or 96h, the proportion of avoiders were well above 50%, ranging from 71 to 94%. At each LC50, considering also avoiders, populations would decline by 85-97%. Furthermore, for D. magna and X. laevis it was noticed that at the lowest conductivities eliciting mortality, the avoidance already exceeded 50%. The results showed that the emigration from salinity-disturbed habitats exists and that can even be more sensitive than standard endpoints. Looking solely to standard endpoints involving forced exposure may greatly underestimate the risk of local population extinction, because habitat function can be severely disrupted, with subsequent stressor-driven emigration, before any adverse physiological effects at the organism level. Thus, the present study highlights the need to include non-forced exposure testing into ecological risk assessment, namely of salinity-menaced costal freshwaters.


Assuntos
Migração Animal , Mudança Climática , Ecossistema , Água do Mar/análise , Animais , Organismos Aquáticos , Água Doce
8.
Ecotoxicol Environ Saf ; 172: 348-355, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-30731265

RESUMO

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.


Assuntos
Aclimatação , Perciformes/fisiologia , Ranidae/fisiologia , Salinidade , Tolerância ao Sal , Animais , Água Doce/química , Larva/fisiologia , Água do Mar/química , Cloreto de Sódio/análise , Estresse Fisiológico
9.
Artigo em Inglês | MEDLINE | ID: mdl-30509925

RESUMO

Salinization of coastal freshwater ecosystems is already occurring in some regions of the world. This phenomenon raises serious concerns on the protection of coastal freshwater ecosystems, since many of them support and shelter a large number of species and are considered hotspots of biodiversity. This work intended to assess the adverse effects that salinization, caused by the intrusion of seawater (SW), may pose to freshwater organisms. In this study, three specific goals were addressed: (i) to assess if sodium chloride (NaCl) may be used as a surrogate of natural SW at early-stages of risk assessment; (ii) to identify the most sensitive freshwater species to salinity NaCl; and (iii) to determine if increased tolerance to salinity may be acquired after multigenerational exposure to low levels of salinization (induced with NaCl). A total of 12 standard monospecific bioassays were carried out by exposing organisms from different taxonomic groups (Cyanobacteria: one species, Tracheophyta: two species, Rotifera: one species, Arthropoda: two species and Mollusca: one species) to a series of concentrations of NaCl (ranging from 0.95 to 22.8 mS cm-1) or dilutions of SW (ranging from 1.70 to 52.3 mS cm-1). In general, NaCl exerted similar or higher toxicity than SW, both at lethal and sublethal levels, suggesting that it may be proposed as a protective surrogate of SW for first tiers of salinization risk assessment. Among all tested species, the cyanobacterium Cylindrospermopsis raciborskii, the daphnid Daphnia longispina and the rotifer Brachionus plicatilis were the most sensitive taxa to salinization (EC50 ≤ 4.38 mS cm-1). Given their position at the basis of the food web, it is suggested that small increments of salinity may be enough to induce structural changes in freshwater communities or induce changes in trophic relations. No clear evidences of increased tolerance after multigenerational exposure to low levels of salinity were found.This article is part of the theme issue 'Salt in freshwaters: causes, ecological consequences and future prospects'.


Assuntos
Organismos Aquáticos/efeitos dos fármacos , Cadeia Alimentar , Salinidade , Água do Mar/efeitos adversos , Cloreto de Sódio/efeitos adversos , Organismos Aquáticos/fisiologia , Água Doce/química , Medição de Risco/métodos , Testes de Toxicidade
10.
Food Funct ; 9(8): 4419-4428, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30066000

RESUMO

Cancers induced by human papillomavirus (HPV) infection remain a significant public health threat, fueling the study of new therapies. Laurel (Laurus nobilis) compounds and extracts recently showed in vitro activity against HPV-transformed cell lines. This work aims to evaluate the in vivo efficacy and hepatic toxicity of a laurel extract in a transgenic mouse model of HPV16-induced cancer. The extract was administered in drinking water (20 mg per animal per day) for three consecutive weeks, using four experimental groups (n = 10) (group I: HPV16-/- without treatment, group II: treated HPV16-/-, group III: HPV16+/- without treatment and group IV: treated HPV16+/-). Following the treatment period, animals were sacrificed and skin samples were used to classify skin lesions histologically. Toxicological parameters included hematological and biochemical blood markers, splenic and hepatic histology and hepatic oxidative stress. The extract did not prevent the progression of HPV16-induced cutaneous lesions in this model. The treated wild-type animals showed mild hepatitis, while transgenic animals suffered weight loss. However, there were no changes concerning hematological, biochemical and hepatic oxidative stress markers.


Assuntos
Antineoplásicos Fitogênicos/toxicidade , Papillomavirus Humano 16/fisiologia , Laurus/química , Infecções por Papillomavirus/virologia , Extratos Vegetais/toxicidade , Neoplasias do Colo do Útero/virologia , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Feminino , Papillomavirus Humano 16/genética , Humanos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Camundongos , Camundongos Transgênicos , Estresse Oxidativo/efeitos dos fármacos , Infecções por Papillomavirus/metabolismo , Infecções por Papillomavirus/patologia , Extratos Vegetais/administração & dosagem , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/patologia
11.
Sci Total Environ ; 619-620: 194-202, 2018 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-29149743

RESUMO

Sea level rise, as a consequence of climate changes, is already causing seawater intrusion in some freshwater coastal ecosystems worldwide. The increase in salinity at these freshwater coastal ecosystems may occur gradually (through groundwater) or abruptly (through extreme weather events). Moreover, many of them are also being altered and threatened by anthropogenic activities. Accordingly, the present study aimed at assessing the multigenerational lethal and sublethal effects caused by increased salinity in six clonal lineages of the freshwater cladoceran Daphnia longispina differing in their sensitivity to lethal levels of copper. Three specific objectives were delineated: i) to compare the lethal and sublethal toxicity of sodium chloride (NaCl) and natural seawater (SW); ii) to evaluate possible multigenerational effects after exposure to low levels of salinity, and iii) to evaluate if an association exists between tolerance to lethal and sublethal levels of salinity and tolerance to metals. Overall, NaCl was found to elicit sublethal effects at lower or similar concentrations than SW, suggesting its use as a protective surrogate of SW in early phases of ecological risk assessment schemes. Multigenerational exposure to conductivities of 0.73±0.015mScm-1 led to dissimilar responses by the six clonal lineages. Significant associations were found neither between lethal and sublethal endpoints nor between salinity and metals, possibly indicating the absence of common mechanisms responsible to confer metal tolerance and salt stress. However, some clonal lineages presented an inverse sensitivity to lethal levels of NaCl and of copper. These results suggest that natural populations of D. longispina, by exhibiting clonal lineages with differential tolerance to increased salinity, may cope with long-term exposure to small increases of this stressor. However, over time those populations may face the occurrence of genetic erosion due to the loss of the most sensitive genotypes before or after a multigenerational exposure.


Assuntos
Cobre/toxicidade , Daphnia/fisiologia , Salinidade , Cloreto de Sódio/toxicidade , Animais , Daphnia/genética , Exposição Ambiental/efeitos adversos , Água Doce/química , Genótipo
12.
Environ Pollut ; 231(Pt 2): 1633-1641, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28964607

RESUMO

Soil salinization, as the combination of primary and secondary events, can adversely affect organisms inhabiting this compartment. In the present study, the effects of increased salinity were assessed in four species of terrestrial fungi: Lentinus sajor caju, Phanerochaete chrysosporium, Rhizopus oryzae and Trametes versicolor. The mycelial growth and biochemical composition of the four fungi were determined under three exposure scenarios: 1) exposure to serial dilutions of natural seawater (SW), 2) exposure to serial concentrations of NaCl (potential surrogate of SW); and 3) exposure to serial concentrations of NaCl after a period of pre-exposure to low levels of NaCl. The toxicity of NaCl was slightly higher than that of SW, for all fungi species: the conductivities causing 50% of growth inhibition (EC50) were within 14.9 and 22.0 mScm-1 for NaCl and within 20.2 and 34.1 mScm-1 for SW. Phanerochaete chrysosporium showed to be the less sensitive species, both for NaCl and SW. Exposure to NaCl caused changes in the biochemical composition of fungi, mainly increasing the production of polysaccharides. When fungi were exposed to SW this pattern of biochemical response was not observed. Fungi pre-exposed to low levels of salinity presented higher EC50 than fungi non-pre-exposed, though 95% confidence limits overlapped, with the exception of P. chrysosporium. Pre-exposure to low levels of NaCl also induced changes in the biochemical composition of the mycelia of L. sajor caju and R. oryzae, relatively to the respective control. These results suggest that some terrestrial fungi may acquire an increased tolerance to NaCl after being pre-exposed to low levels of this salt, thus, suggesting their capacity to persist in environments that will undergo salinization. Furthermore, NaCl could be used as a protective surrogate of SW to derive safe salinity levels for soils, since it induced toxicity similar or higher than that of SW.


Assuntos
Basidiomycota/efeitos dos fármacos , Micélio/efeitos dos fármacos , Rhizopus/efeitos dos fármacos , Microbiologia do Solo/normas , Solo/química , Basidiomycota/crescimento & desenvolvimento , Micélio/crescimento & desenvolvimento , Rhizopus/crescimento & desenvolvimento , Salinidade , Tolerância ao Sal/efeitos dos fármacos , Água do Mar/química , Cloreto de Sódio/toxicidade
13.
Environ Sci Pollut Res Int ; 24(6): 5888-5897, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28064393

RESUMO

Within the context of global climate changes, it is expected that low-lying coastal freshwater ecosystems will face seawater intrusion with concomitant increase in salinity levels. Increased salinity may provoke disruption of competitive relationships among freshwater species. However, species may be capable of acclimating to salinity, which, in turn, may influence the resilience of ecosystems. Accordingly, this work aimed at assessing the effects of multigenerational exposure to low levels of salinity in the competitive outcome of two species of green microalgae: Raphidocelis subcapitata and Chlorella vulgaris. To attain this, three specific objectives were delineated: (1) compare the toxicity of natural seawater (SW) and NaCl (as a surrogate of SW) to the two microalgae, (2) determine the capacity of the two microalgae species to acclimate to low salinity levels, and (3) assess the influence of exposure to low salinity levels in the competitive outcome of the two microalgae. Results revealed SW to be slightly less toxic than NaCl for the two microalgae. The EC25,72 h for growth rate was 4.63 and 10.3 mS cm-1 for R. subcapitata and 6.94 and 15.4 mS cm-1 for C. vulgaris, respectively for NaCl and SW. Both algae were capable of acclimating to low levels of salinity, but C. vulgaris seemed to acclimate faster than R. subcapitata. When exposed in competition, under control conditions, the growth rates of C. vulgaris were lower than those of R. subcapitata. However, C. vulgaris was capable of acquiring competitive advantage equaling or surpassing the growth rate of R. subcapitata with the addition of NaCl or SW, respectively. The multigenerational exposure to low levels of salinity influenced the competitive outcome of the two algae both under control and salinity exposure. These results suggest that long-term exposure to low salinity stress can cause shifts in structure of algae communities and, therefore, should not be neglected since algae are at the basis of food web constituting important energetic resources to higher trophic levels.


Assuntos
Chlorella vulgaris/crescimento & desenvolvimento , Microalgas/crescimento & desenvolvimento , Aclimatação , Chlorella vulgaris/efeitos dos fármacos , Microalgas/efeitos dos fármacos , Salinidade , Água do Mar/química , Cloreto de Sódio/farmacologia
14.
Curr Neuropharmacol ; 9(1): 251-5, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21886600

RESUMO

Ketamine is a noncompetitive antagonist of the NMDA-receptors, used as a dissociative anesthetic, presently included in the category of the psychoactive substances known as "club drugs". Ketamine administration was associated with impaired working memory and increased psychopathological symptoms, but there is a lack of information regarding the effects of chronic sub-anesthetic doses. Adult Wistar rats were administered ketamine, 5 and 10 mg/kg twice daily, subcutaneously for 14 days. One week later, rats were tested in an object recognition/object location task and in the open field arena. There was altered performance in both the object recognition/location and in the open field tests by the group chronically exposed to the lower dose of ketamine. These animals displayed a decreased discrimination index (p<0.05) in the object recognition task, were unable to recognize the displacement of a familiar object and displayed decreased activity across open filed sessions. Importantly, these alterations were not observed in animals administered a higher dose of ketamine. Collectively, these results consistently show that chronic administration of ketamine in sub-anesthetic doses may lead to decreased habituation and inability to update spatial representations.

15.
Br J Anaesth ; 106(4): 540-7, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21296767

RESUMO

BACKGROUND: The index of consciousness (IoC), the permutation entropy (PE), and the approximate entropy are recent EEG-derived indices of anaesthetic depth. In this study, a rabbit model under fentanyl and isoflurane anaesthesia was used to compare the performance of these indices and also the classic median and spectral edge frequency 95%. METHODS: EEG recordings were obtained from six rabbits. Animals received fentanyl for premedication, followed by induction with propofol and maintenance with isoflurane. Anaesthetic depth was evaluated according to a clinical scale from 1 (awake) to 4 (surgical anaesthesia). Animals were submitted to surgical implantation of a small device in the lumbar muscles. A correction factor for the EEG suppression ratio was applied to the spectral parameters and to the PE. The correlation of the indices with the clinical scale of anaesthesia was analysed using prediction probability. Repeated-measures analysis of variance or its non-parametric equivalent was used to analyse the indices values at the study times and to compare their variability. RESULTS: The IoC showed the best mean prediction probability value [0.94 (0.01)] followed by burst suppression-corrected PE [0.91(0.03)]. Both parameters also showed less variability than the others. CONCLUSIONS: The IoC and PE are promising indices for anaesthetic depth monitoring. The PE might benefit from the application of a burst suppression correction at deeper stages of anaesthesia. The rabbit is useful as a translational research animal model for the validation of clinical indices.


Assuntos
Anestésicos Inalatórios/farmacologia , Estado de Consciência/efeitos dos fármacos , Isoflurano/farmacologia , Monitorização Intraoperatória/métodos , Anestésicos Combinados/farmacologia , Anestésicos Intravenosos/farmacologia , Animais , Estado de Consciência/fisiologia , Eletroencefalografia/efeitos dos fármacos , Eletroencefalografia/métodos , Entropia , Fentanila/farmacologia , Masculino , Modelos Animais , Coelhos , Processamento de Sinais Assistido por Computador
16.
São Paulo; s.n; 2009. 1 p.
Não convencional em Português | Coleciona SUS, HSPM-Producao, Sec. Munic. Saúde SP, Sec. Munic. Saúde SP | ID: biblio-937233

RESUMO

Foram avaliados 50 pacientes, 35 (70%) mulheres e 15 (30%) homens, com média de idade de 77,74 anos. Não houve diferença entre os grupos em relação ao índice de Pfeffer. O QOL-AD mostrou diferença estatisticamente significante entre os grupos com e sem depressão. Conclusão: a depressão é um fator importante de piora da qualidade de vida em idosos com demência de leve a moderada intensidade e deve ser tratada também nesses pacientes


Assuntos
Idoso , Demência/diagnóstico , Demência/terapia , Depressão/diagnóstico , Depressão/terapia , Qualidade de Vida
17.
São Paulo; s.n; 2009. 1 p.
Não convencional em Português | Sec. Munic. Saúde SP, HSPM-Producao, Sec. Munic. Saúde SP, Sec. Munic. Saúde SP | ID: sms-1673

RESUMO

Foram avaliados 50 pacientes, 35 (70%) mulheres e 15 (30%) homens, com média de idade de 77,74 anos. Não houve diferença entre os grupos em relação ao índice de Pfeffer. O QOL-AD mostrou diferença estatisticamente significante entre os grupos com e sem depressão. Conclusão: a depressão é um fator importante de piora da qualidade de vida em idosos com demência de leve a moderada intensidade e deve ser tratada também nesses pacientes (AU)


Assuntos
Qualidade de Vida , Idoso , Depressão/diagnóstico , Depressão/terapia , Demência/diagnóstico , Demência/terapia
18.
São Paulo; s.n; 2008. 1 p.
Não convencional em Português | Coleciona SUS, HSPM-Producao, Sec. Munic. Saúde SP, Sec. Munic. Saúde SP | ID: biblio-936839

RESUMO

A paralisia supranuclear progressiva é uma doença rara com predomínio no sexo masculino descrita entre as patologias conhecidas como parkinsonismo atípico. Y.O.N, 66 anos, branca, feminina, brasileira, residente em São Paulo, nível superior, enfermeira aposentada. Queixava-se de disfonia associada à perda de peso progressiva, dificuldade em iniciar movimentos, lentificação, rigidez, apatia, desmotivação, tonturas e quedas freqüentes há aproximadamente 3 anos. Neste período, refere piora progressiva da marcha. Há 1 ano apresentou queda com luxação de ombro direito sendo submetida a procedimento cirúrgico. No último ano iniciou com quadro de distúrbio comportamental, irritabilidade, desinibição e agressividade. Negava comorbidades prévias. Ao exame físico geral apresentava-se emagrecida, com hiperextensão de tronco e coluna cervical, alteração da marcha com necessidade de auxílio, fáscies de espanto, disartria, perda do olhar vertical para baixo. Força muscular diminuida +/5+ em membros inferiores com atrofia muscular, rigidez, sem tremores de extremidade. MEEM 28/30 FV 8/minuto, Teste do relógio 0. À ressonância magnética apresentou sinais de dilataçãodo sistema ventricular, alargamento dos sulcos corticais, cisternas basais e sylvianas, raras zonas de alteração da intensidade de sinal localizada na substância branca periventricular compatíveis com áreas de glicose. O quadro clínico e a perda do olhar conjugado vertical para baixo sugeriram uma hipótese diagnóstica de possível paralisia supranuclear progressiva. O relato de caso demonstra a dificuldade do diagnóstico de pacientes que apresentam déficit cognitivo, alteração de comportamento e alterações neurológicas e um alerta à comunidade científica da possibilidade desse diagnóstico


Assuntos
Geriatria , Transtornos Parkinsonianos , Doença de Parkinson/diagnóstico , Doença de Parkinson/terapia
19.
São Paulo; s.n; 2008. 1 p.
Não convencional em Português | Sec. Munic. Saúde SP, HSPM-Producao, Sec. Munic. Saúde SP, Sec. Munic. Saúde SP | ID: sms-898

RESUMO

A paralisia supranuclear progressiva é uma doença rara com predomínio no sexo masculino descrita entre as patologias conhecidas como parkinsonismo atípico. Y.O.N, 66 anos, branca, feminina, brasileira, residente em São Paulo, nível superior, enfermeira aposentada. Queixava-se de disfonia associada à perda de peso progressiva, dificuldade em iniciar movimentos, lentificação, rigidez, apatia, desmotivação, tonturas e quedas freqüentes há aproximadamente 3 anos. Neste período, refere piora progressiva da marcha. Há 1 ano apresentou queda com luxação de ombro direito sendo submetida a procedimento cirúrgico. No último ano iniciou com quadro de distúrbio comportamental, irritabilidade, desinibição e agressividade. Negava comorbidades prévias. Ao exame físico geral apresentava-se emagrecida, com hiperextensão de tronco e coluna cervical, alteração da marcha com necessidade de auxílio, fáscies de espanto, disartria, perda do olhar vertical para baixo. Força muscular diminuida +/5+ em membros inferiores com atrofia muscular, rigidez, sem tremores de extremidade. MEEM 28/30 FV 8/minuto, Teste do relógio 0. À ressonância magnética apresentou sinais de dilataçãodo sistema ventricular, alargamento dos sulcos corticais, cisternas basais e sylvianas, raras zonas de alteração da intensidade de sinal localizada na substância branca periventricular compatíveis com áreas de glicose. O quadro clínico e a perda do olhar conjugado vertical para baixo sugeriram uma hipótese diagnóstica de possível paralisia supranuclear progressiva. O relato de caso demonstra a dificuldade do diagnóstico de pacientes que apresentam déficit cognitivo, alteração de comportamento e alterações neurológicas e um alerta à comunidade científica da possibilidade desse diagnóstico (AU)


Assuntos
Doença de Parkinson/diagnóstico , Doença de Parkinson/terapia , Transtornos Parkinsonianos , Geriatria
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