Acute recanalization treatments in postnatal paediatric ischaemic arterial stroke. Paediatric stroke code.

In children, arterial ischemic stroke is a much less understood disease compared to in adults due to its lower frequency and different aetiology. However, it is also a serious disease, with a high incidence of severe and permanent sequelae that exceeds 50% of total cases. The acute management of postnatal arterial ischaemic stroke (MNAIS) has changed drastically in recent years, chiefly on account of recanalization treatments (thrombolysis and endovascular therapies). These treatments, which used to not be recommended in childhood, are increasingly implemented in everyday clinical practice. Although the evidence from studies carried out in children is not of high quality due to their retrospective design and the small number of reported cases, they support the hypothesis that these treatments are as safe and effective as they are in adults as long as appropriate eligibility criteria are applied and they are used within a certain time from the onset of symptoms (therapeutic window). This article reviews the MNAIS based on the current scientific evidence. Since the efficacy of these treatments is highly dependent on their early initiation, a paediatric stroke code needs to be in place as an extension of the stroke code applied to adults. It has started to be introduced in Spain since 2019, although there are still large areas of the country where it has yet to be applied.

Rituximab as Second-Line Treatment in Anti-NMDAR Encephalitis after Herpes Simplex Encephalitis in Children.

The long-term response of two infants with anti-N-methyl-D-aspartate receptor (anti-NMDAR) post herpes simplex encephalitis treated with rituximab is reported here. Rituximab may improve the course of the disease and should be considered early as second-line treatment. Data on the long-term effect of rituximab in B cell depletion and immunoglobulins levels in infants are needed.

Intención de vacunarse contra COVID-19 en la población de 40 años en adelante en México

Objetivo Evaluar el efecto de las fuentes de información sobre COVID-19, los beneficios y las barreras percibidas de la vacunación, y la actitud hacia la vacunación sobre la intención de vacunarse contra COVID-19 en la población de 40 años en adelante en México. Métodos Se desarrolló una investigación cuantitativa, transversal y explicativa. Se aplicó una encuesta electrónica a 703 personas de 40 años en adelante que residen en México. El análisis de resultados se realizó a través de la técnica de ecuaciones estructurales por medio del método de mínimos cuadrados parciales. Resultados Las fuentes de información sobre COVID-19 influyen positivamente sobre los beneficios percibidos de la vacuna y disminuyen las barreras percibidas. Además, los beneficios percibidos influyen positivamente sobre la actitud hacia la vacunación de COVID-19; sin embargo, las barreras no afectan la actitud. Adicionalmente, esta última influye en la intención de vacunarse contra COVID-19 e, indirectamente, las fuentes de información y los beneficios percibidos influyen sobre la intención a vacunarse mediados por la actitud.

Objective To evaluate the effect of information sources on COVID-19, the benefits and perceived barriers of vaccination, and the attitude towards vaccination on the intention to get vaccinated against COVID-19 in the population aged 40 and over in Mexico. Methods A quantitative, cross-sectional and explanatory investigation was developed. An electronic survey was applied to 703 people aged 40 and over who reside in Mexico. The analysis of results was carried out through the technique of structural equations by means of the method of partial least squares. Results The sources of information on COVID-19 positively influence the perceived benefits of the vaccine and reduce the perceived barriers. Furthermore, the perceived benefits positively influence the attitude towards COVID-19 vaccination; however, barriers do not affect attitude. Additionally, the latter influences the intention to be vaccinated against COVID-19 and indirectly the sources of information and the perceived benefits influence the intention to be vaccinated mediated by the attitude.

Comparative acute toxicity of benzophenone derivatives and bisphenol analogues in the Asian clam Corbicula fluminea.

Among UV-filters, benzophenones are one of the most abundantly used and detected groups in the environment. Bisphenols are also one of the most widely used chemicals in plastics, but their demonstrated deleterious effects on several organisms and humans have led to the production of alternative analogues. However, few comparative studies on the ecotoxicological effects of these derivatives or analogues have been carried out. The present study aimed to investigate the effects of two benzophenones (BP-3 and BP-4) and two bisphenols (BPA and BPS) in a short-term exposure of the freshwater endobenthic bivalve Corbicula fluminea. Clams were exposed for 96 h to several concentrations of the four pollutants: BP-3 (0.63; 1.25; 2.5; 5 mg l-1), BP-4 (4.75; 9.5; 19; 38 mg l-1), BPA (3.75; 7.5; 15; 30 mg l-1), and BPS (2.5; 5; 10; 20 mg l-1). The comparative acute toxicity of these pollutants was evaluated by the analysis of the post-exposure filtering capacity of clams, lipid peroxidation (LP) levels and the activity of the antioxidant enzymes catalase (CAT) and glutathione reductase (GR). After the exposure period, except for BP-4, the chemicals tested seemed to be detected by clams and provoked valve closure, decreasing filter-feeding in a concentration-dependent manner. Furthermore, C. fluminea exposed to the highest concentrations of BP-3, BP-4 and BPA showed a significant increase in LP, CAT and GR activities with respect to their controls. BP-3 and BPA were the most toxic compounds showing significant differences in all the parameters analysed at the highest concentrations assayed. However, clams exposed to BPS showed only significant alterations in filtration parameters and in GR activity, in the two highest concentrations tested, indicating that this compound was the least toxic to clams. Obtained results highlight the importance of investigating the effects that emerging pollutants have on aquatic organisms.

Severidad, susceptibilidad y normas sociales percibidas como antecedentes de la intención de vacunarse contra coviD-19 / Severity, susceptibility and social norms perceived as antecedents of the intention to be vaccinated against COVID-19

RESUMEN Objetivo Evaluar el efecto del riesgo y las normas sociales percibidos sobre la COVID-19 y sobre la intención de vacunarse si se contara con una vacuna para prevenir la infección. Métodos Se desarrolló una investigación cuantitativa, explicativa y con diseño transversal. Los datos se recopilaron mediante un cuestionario estructurado aplicado de manera electrónica a habitantes de más de 18 años de edad en el estado de Puebla, en México. Se utilizó un análisis con ecuaciones estructurales para identificar los efectos entre las variables estudiadas. Resultados Tanto la severidad como la susceptibilidad percibidas al contraer COVID-19 tuvieron un efecto positivo sobre las normas sociales percibidas sobre el virus. Mientras la severidad percibida tuvo un efecto positivo sobre la intención de vacunarse, la susceptibilidad percibida resultó no significativa sobre la intención de vacunarse contra COVID-19. Conclusiones La intención de vacunarse contra COVID-19 es afectada por la severidad y las normas sociales percibidas por contraer la infección. Sin embargo, la susceptibilidad percibida ante el virus no tiene un efecto sobre la intención de vacunarse.(AU)

ABSTRACT Objective To evaluate the effect of perceived risk and social norms on COVID-19 and on the intention to be vaccinated if a vaccine were available to prevent infection. Methods A quantitative, explanatory and cross-sectional research was developed. The data was collected through a structured questionnaire applied electronically to inhabitants over 18 years of age in the state of Puebla in Mexico. An analysis with structural equations was used to identify the effects among the constructs studied. Results The results showed that both the perceived severity and susceptibility of contracting COVID-19 had a positive effect on the perceived social norms about the virus. Also, while the perceived severity had a positive effect on the intention to vaccinate, the perceived susceptibility was not significant on the intention to vaccinate against COVID-19. Conclusion Intention to be vaccinated against COVID-19 is affected by the severity and perceived social norms of contracting the infection. However, the perceived susceptibility to the virus does not have an effect on the intention to be vaccinated.(AU)

[Severity, susceptibility and social norms perceived as antecedents of the intention to be vaccinated against COVID-19]. / Severidad, susceptibilidad y normas sociales percibidas como antecedentes de la intención de vacunarse contra COVID-19.

OBJECTIVE: To evaluate the effect of perceived risk and social norms on COVID-19 and on the intention to be vaccinated if a vaccine were available to prevent infection. METHODS: A quantitative, explanatory and cross-sectional research was developed. The data was collected through a structured questionnaire applied electronically to inhabitants over 18 years of age in the state of Puebla in Mexico. An analysis with structural equations was used to identify the effects among the constructs studied. RESULTS: The results showed that both the perceived severity and susceptibility of contracting COVID-19 had a positive effect on the perceived social norms about the virus. Also, while the perceived severity had a positive effect on the intention to vaccinate, the perceived susceptibility was not significant on the intention to vaccinate against COVID-19. CONCLUSION: Intention to be vaccinated against COVID-19 is affected by the severity and perceived social norms of contracting the infection. However, the perceived susceptibility to the virus does not have an effect on the intention to be vaccinated.

Differential toxicity of the UV-filters BP-3 and BP-4 in Chlamydomonas reinhardtii: A flow cytometric approach.

Due to the concern about the negative effects of exposure to sunlight, UV-filters are being introduced in all kind of cosmetic formulas. Wastewater treatment plants are not able to remove and/or degrade them; consequently they find their way into rivers, lakes and oceans. These chemicals are acquiring a concerning status due to their increasingly common use and the potential risk for the environment. Benzophenone-3 (BP-3) and Benzophenone-4 (BP-4) are broad-spectrum UV-filters used for the same purpose in personal care products, insecticides and plastic bags; however, after 96 h of exposure to several concentrations of these UV-filters, the growth of C. reinhardtii was more affected by BP-3 than by BP-4, being the 96 h-EC50 for growth 5 mg L-1 and 38 mg L-1, respectively. Based on these values Chlamydomonas reinhardtii cultures were exposed during 24 h to 2.5, 5 and 10 mg L-1 of BP-3 and 19, 38 and 76 mg L-1 of BP-4. A cytometric panel was carried out to evaluate the effect of sublethal concentrations of these UV-filters, thus several cytotoxicity biomarkers were analysed, including chlorophyll a fluorescence, viability, metabolic activity, oxidative stress, cytoplasmic and mitochondrial membrane potentials, and intracellular pH. BP-3 and BP-4 affect C.reinhardtii cells in a different way, showing differences for three of the examined parameters. Chlorophyll a fluorescence and mitochondrial membrane potential showed a significant increase (p < 0.05) in BP-3 and a significant decrease in BP-4, whereas viability only decreased significantly in the highest concentrations of BP-3. Regarding to the other parameters analysed, a similar pattern of cytotoxicity was observed. Growth rate, vital population and metabolic activity (esterase activity) and intracellular pH decreased significantly and cytoplasmic membrane potential and ROS levels increased significantly in cultures exposed to both pollutants.

Evaluación del manejo del dolor de la patología facial y oral en un Servicio de Urgencias Pediátrico y tras el alta domiciliaria / Assessment of orofacial pain management in a pediatric emergency department and at home after discharge

Introducción. El manejo inadecuado del dolor es frecuente en Urgencias. El objetivo fue analizar el manejo del dolor de niños con patología infecciosa o traumática del área facial/oral en Urgencias y evaluar el cumplimiento y satisfacción sobre la analgesia prescrita al momento del alta. Población y métodos. Estudio transversal, observacional y analítico en niños que acudieron a Urgencias con patología infecciosa/traumática de la región facial/oral durante 2 meses. Se recogieron el manejo del dolor en Urgencias, la analgesia prescrita para el domicilio y, tras el contacto telefónico con los padres, el tratamiento realizado y su adecuación al dolor del niño. Resultados. Fueron incluidos 252 pacientes (edad media de 4,5 años, desvío estándar 3,89). En 8,7%, figuraba la evaluación del dolor en triaje y, en 3,6%, en el informe médico. Se administró analgesia en Urgencias al 41,3%. Al momento del alta, en un 13,9%, no se prescribió analgesia; en 25,4%, se prescribió pautada y, en 60,3%, a demanda. Los pediatras usaron más analgesia pautada que los cirujanos (34,4% vs. 16,5%, p < 0,01). En el domicilio, no administraron analgesia en el 39,3%; en un 36,1%, pautada y, en un 23%, a demanda. Existió escasa correlación entre la pauta al momento del alta y la administrada en el domicilio (kappa: 0,178). Se consideró la analgesia adecuada en el 84%, con más frecuencia en patología traumática que infecciosa (85,7% vs. 14,3%, p < 0,01). Conclusiones. Se observó escasa evaluación y tratamiento del dolor en Urgencias. La prescripción más usada fue a demanda en vez de pautada, al contrario de lo recomendado en las guías. El control analgésico fue mejor en patología traumática que infecciosa.

Introduction. An inadequate pain management is common in the emergency department. Our objective was to analyze pain management among children with an orofacial infection or trauma in the emergency department and to assess compliance and satisfaction with analgesia prescribed at discharge. Population and methods. Cross-sectional, observational and analytical study in children attending the emergency department for an orofacial infection or trauma over 2 months. Pain management in the emergency department, analgesia prescribed at home and, following a call to parents, treatment provided and its adequacy to control pain were registered. Results. In total, 252patients (mean age: 4.5 years, SD: 3.89) were included. Pain assessment was recorded at the triage for 8.7%, and in the medical report, for 3.6%. Analgesia was administered to 41.3% in the emergency room. At discharge, no analgesia was prescribed to 13.9%; scheduled analgesia, to 25.4%; and as needed, to 60.3%. Pediatricians prescribed scheduled analgesia more frequently than surgeons (34.4% versus 16.5%, p < 0.01). At home, no analgesia was administered to 39.3%; scheduled analgesia, to 36.1%; and as needed, to 23%. There is little correlation between prescription at discharge and at home (Kappa: 0.178). Analgesia was considered adequate in 84% of cases, and was more frequent in trauma injuries than in infections (85.7% versus 14.3%, p < 0.01). Conclusions. Pain assessment and management was scarce in the emergency department. The most common prescription was as needed, contrary to what is recommended in the guidelines. Analgesic control worked better for trauma injuries than for infections.

Assessment of orofacial pain management in a pediatric emergency department and at home after discharge. / Evaluación del manejo del dolor de la patología facial y oral en un Servicio de Urgencias Pediátrico y tras el alta domiciliaria.

INTRODUCTION: An inadequate pain management is common in the emergency department. Our objective was to analyze pain management among children with an orofacial infection or trauma in the emergency department and to assess compliance and satisfaction with analgesia prescribed at discharge. POPULATION AND METHODS: Cross-sectional, observational and analytical study in children attending the emergency department for an orofacial infection or trauma over 2 months. Pain management in the emergency department, analgesia prescribed at home and, following a call to parents, treatment provided and its adequacy to control pain were registered. RESULTS: In total, 252patients (mean age: 4.5 years, SD: 3.89) were included. Pain assessment was recorded at the triage for 8.7%, and in the medical report, for 3.6%. Analgesia was administered to 41.3% in the emergency room. At discharge, no analgesia was prescribed to 13.9%; scheduled analgesia, to 25.4%; and as needed, to 60.3%. Pediatricians prescribed scheduled analgesia more frequently than surgeons (34.4% versus 16.5%, p < 0.01). At home, no analgesia was administered to 39.3%; scheduled analgesia, to 36.1%; and as needed, to 23%. There is little correlation between prescription at discharge and at home (Kappa: 0.178). Analgesia was considered adequate in 84% of cases, and was more frequent in trauma injuries than in infections (85.7% versus 14.3%, p < 0.01). CONCLUSIONS: Pain assessment and management was scarce in the emergency department. The most common prescription was as needed, contrary to what is recommended in the guidelines. Analgesic control worked better for trauma injuries than for infections.

INTRODUCCIÓN: El manejo inadecuado del dolor es frecuente en Urgencias. El objetivo fue analizar el manejo del dolor de niños con patología infecciosa o traumática del área facial/oral en Urgencias y evaluar el cumplimiento y satisfacción sobre la analgesia prescrita al momento del alta. POBLACIÓN Y MÉTODOS: Estudio transversal, observacional y analítico en niños que acudieron a Urgencias con patología infecciosa/traumática de la región facial/oral durante 2 meses. Se recogieron el manejo del dolor en Urgencias, la analgesia prescrita para el domicilio y, tras el contacto telefónico con los padres, el tratamiento realizado y su adecuación al dolor del niño. RESULTADOS: Fueron incluidos 252 pacientes (edad media de 4,5 años, desvío estándar 3,89). En 8,7%, figuraba la evaluación del dolor en triaje y, en 3,6%, en el informe médico. Se administró analgesia en Urgencias al 41,3%. Al momento del alta, en un 13,9%, no se prescribió analgesia; en 25,4%, se prescribió pautada y, en 60,3%, a demanda. Los pediatras usaron más analgesia pautada que los cirujanos (34,4% vs. 16,5%, p < 0,01). En el domicilio, no administraron analgesia en el 39,3%; en un 36,1%, pautada y, en un 23%, a demanda. Existió escasa correlación entre la pauta al momento del alta y la administrada en el domicilio (kappa: 0,178). Se consideró la analgesia adecuada en el 84%, con más frecuencia en patología traumática que infecciosa (85,7% vs. 14,3%, p < 0,01). CONCLUSIONES: Se observó escasa evaluación y tratamiento del dolor en Urgencias. La prescripción más usada fue a demanda en vez de pautada, al contrario de lo recomendado en las guías. El control analgésico fue mejor en patología traumática que infecciosa.

Flow cytometric assay to assess short-term effects of personal care products on the marine microalga Tetraselmis suecica.

Large quantities of personal care products (PCPs) are used daily and many of their chemical ingredients are subsequently released into marine environments. Cultures of the marine microalga Tetraselmis suecica were exposed for 24 h to three emerging compounds included in the main classes of PCPs: the UV filter benzophenone-3 (BP-3), the disinfectant triclosan (TCS) and the fragrance tonalide (AHTN). Concentrations tested, expressed as cellular quota (pg cell-1), ranged from 5 to 40 for BP-3, from 2 to 16 for TCS and from 1.2 to 2.4 for AHTN. A small cytometric panel was carried out to evaluate key cytotoxicity biomarkers including inherent cell properties, growth and metabolic activity and cytoplasmic membrane properties. BP-3 caused a significant increase in growth rate, metabolic activity and chlorophyll a fluorescence from 10 pg cell-1. However, growth and esterase activity decreased in cells exposed to all TCS and AHTN concentrations, except the lowest ones. Also these two compounds provoked a significant swelling of cells, more pronounced in the case of TCS-exposed cells. Although all treated cells remained viable, changes in membrane potential were observed. BP-3 and AHTN caused a significant depolarization of cells from 10 to 1.6 pg cell-1, respectively; however all TCS concentrations assayed caused a noticeable hyperpolarization of cells. Metabolic activity and cytoplasmic membrane potential were the most sensitive parameters. It can be concluded that the toxicological model used and the toxicological parameters evaluated are suitable to assess the toxicity of these emerging contaminants.

Early alterations on photosynthesis-related parameters in Chlamydomonas reinhardtii cells exposed to atrazine: A multiple approach study.

Chlamydomonas reinhardtii cells were exposed to a sublethal concentration of the widespread herbicide atrazine for 3h. Physiological cellular parameters, such as chlorophyll a fluorescence and oxidative stress monitored by flow cytometry and pigments levels were altered in microalgal cells exposed to 0.25 µM of atrazine. Furthermore, the effects of this herbicide on C. reinhardtii were explored using "omics" techniques. Transcriptomic analyses, carried out by RNA-Seq technique, displayed 9 differentially expressed genes, related to photosynthesis, between control cultures and atrazine exposed cultures. Proteomic profiles were obtained using iTRAQ tags and MALDI-MS/MS analysis, identifying important changes in the proteome during atrazine stress; 5 proteins related to photosynthesis were downexpressed. The results of these experiments advance the understanding of photosynthetic adjustments that occur during an early herbicide exposure. Inhibition of photosynthesis induced by atrazine toxicity will affect the entire physiological and biochemical states of microalgal cells.

Acute effects of a prooxidant herbicide on the microalga Chlamydomonas reinhardtii: Screening cytotoxicity and genotoxicity endpoints.

Since recent evidence has demonstrated that many types of chemicals exhibit oxidative and/or genotoxic potential on living organisms, reactive oxygen species (ROS) formation and DNA damage are currently the best accepted paradigms to assess the potential hazardous biological effects of a wide range of contaminants. The goal of this study was to evaluate the sensitivity of different cytotoxicity and genotoxicity responses on the model microalga Chlamydomonas reinhardtii exposed to the prooxidant herbicide paraquat. In addition to the growth endpoint, cell viability, mitochondrial membrane potential and presence of reactive oxygen species (ROS) were assayed as potential markers of cytotoxicity using flow cytometry (FCM). To study the effects of paraquat on C. reinhardtii DNA, several genotoxicity approaches were implemented for the first time in an ecotoxicological study on microalgae. Oxidative DNA base damage was analysed by measuring the oxidative DNA lesion 8-OHdG by FCM. DNA fragmentation was analysed by different methods: comet assay, and cell cycle analysis by FCM, with a particular focus on the presence of subG1-nuclei. Finally, effects on morphology of nuclei were monitored through DAPI staining. The evaluation of these endpoints showed that several physiological and biochemical parameters reacted to oxidative stress disturbances with greater sensitivity than integrative parameters such as growth rates or cell viability. The experiments revealed concentration-dependent cytotoxicity (ROS formation, depolarization of mitochondrial membrane), genotoxicity (oxidative DNA damage, DNA strand breakage, alterations in nuclear morphology), and cell cycle disturbances (subG1-nuclei, decrease of 4N population) in paraquat-treated cells. Overall, the genotoxicity results indicate that the production of ROS caused by exposure to paraquat induces oxidative DNA damage followed by DNA single- and double-strand breaks and cell cycle alterations, possibly leading to apoptosis in C. reinhardtii cells. This is supported by the observation of typical hallmarks of apoptosis, such as mitochondrial membrane depolarization, alterations in nuclear morphology and subG1 nuclei in cells exposed to the highest assayed concentrations. To our knowledge, this is the first study that provides a comprehensive analysis of oxidative DNA base damage in unicellular algal cells exposed to a prooxidant pollutant, as well as of its possible relation with other physiological effects. These results reinforce the need for additional studies on the genotoxicity of environmental pollutants on ecologically relevant organisms such as microalgae that can provide a promising basis for the characterization of potential pollutant hazards in the aquatic environment.

Chlamydomonas reinhardtii cells adjust the metabolism to maintain viability in response to atrazine stress.

Chlamydomonas reinhardtii cells were exposed to a sublethal concentration of the widespread herbicide atrazine for 3 and 24h. Physiological parameters related to cellular energy status, such as cellular activity and mitochondrial and cytoplasmic membrane potentials, monitored by flow cytometry, were altered in microalgal cells exposed to 0.25µM of atrazine. Transcriptomic analyses, carried out by RNA-Seq technique, displayed 12 differentially expressed genes between control cultures and atrazine-exposed cultures at both tested times. Many cellular processes were affected, but the most significant changes were observed in genes implicated in amino acid catabolism and respiratory cellular process. Obtained results suggest that photosynthesis inhibition by atrazine leads cells to get energy through a heterotrophic metabolism to maintain their viability.

Suitability of cytotoxicity endpoints and test microalgal species to disclose the toxic effect of common aquatic pollutants.

Pulse discharges of chemicals to aquatic environments may lead to high concentrations of them in surface waters for short periods of time, but enough to induce toxic effects on aquatic organisms; however, no many methods allow an early warning of toxicity of these agents. Acute effects of one representative chemical from each of three of the main groups of aquatic pollutants (pesticides, metals and pharmaceuticals) are studied on two green microalgal species (Chlamydomonas moewusii and Chlorella vulgaris). Flow cytometry protocols were used to detect the potential application of chlorophyll a fluorescent emission, cell viability, metabolic activity and membrane potential as cytotoxicity endpoints, besides an epifluorescence microscopy protocol for comet assay to detect genotoxicity level of cells. Obtained results confirm the suitability of them for the prospective assessment of the potential cytotoxicity of these aquatic pollutants. The two microalgal species analysed could be used as indicators in toxicity bioassays, being C. moewusii more sensitive than C. vulgaris. Among cell parameters assayed, the metabolic activity and the primary DNA damage stood out as sensitive cytotoxicity endpoints.

Toxicity induced by three antibiotics commonly used in aquaculture on the marine microalga Tetraselmis suecica (Kylin) Butch.

Aquaculture facilities are a potential source of antibiotics to the aquatic ecosystems. The presence of these compounds in the environment may have deleterious effects on non-target aquatic organisms such as microalgae, which are often used as biological indicators of pollution. Therefore, the toxicity induced by chloramphenicol (CHL), florphenicol (FLO) and oxytetracycline (OTC), three antibiotics widely used in aquaculture, on the marine microalga Tetraselmis suecica was evaluated. Growth inhibition and physiological and biochemical parameters were analysed. All three antibiotics inhibited growth of T. suecica with 96 h IC50 values of 11.16, 9.03 and 17.25 mg L(-1) for CHL, FLO and OTC, respectively. After 24 h of exposure no effects on growth were observed and cell viability was also unaffected, whereas a decrease in esterase activity, related with cell vitality, was observed at the higher concentrations assayed. Photosynthesis related parameters such as chlorophyll a cellular content and autofluorescence were also altered after 24 h of antibiotics addition. It can be concluded that T. suecica was sensitive to the three antibiotics tested.

Isotherm studies for the determination of Cd (II) ions removal capacity in living biomass of a microalga with high tolerance to cadmium toxicity.

The biosorption characteristics of Cd (II) ions using the living biomass of the marine diatom Phaeodactylum tricornutum were investigated. This microalga is a highly tolerant species to cadmium toxicity; for this reason, it is interesting to know its potential for use in the removal of this metal. The use of living biomass offers better possibilities than that of dead biomass since cadmium can also be bioaccumulated inside the cells. For this purpose, tolerant species are necessary. P. tricornutum is within this category with an EC50,96h of 19.1 ± 3.5 mg Cd (II)/L, and in the present manuscript, it is demonstrated that this microalga has a very good potential for bioremediation of Cd (II) ions in saline habitats. Cadmium removed by the cells was divided into three fractions: total, intracellular and bioadsorbed. The experiments were conducted for 96 h in natural seawater with a concentration range of 1-100 mg Cd (II)/L. Each fraction was characterized every 24 h by sorption isotherms. The experimental isotherm data were analyzed using the Langmuir, Freundlich, Dubinin-Radushkevich and Temkin equations. The biosorption was well described by Langmuir isotherm followed by Freundlich. The worst model was Temkin. The biosorption capacity of this microalga for Cd (II) ions was found to be 67.1 ± 3.2 mg/g after 96 h with approximately 40 % of this capacity in the intracellular fraction. The bioconcentration factor determined was 2,204.7 after 96 h and with an initial Cd (II) concentration of 1 mg/L.

Screening acute cytotoxicity biomarkers using a microalga as test organism.

The present study checked the suitability of the integration of flow cytometry (FCM) as technique and a freshwater microalga (Chlamydomonas moewusii) as cell system model for ecotoxicological studies, looking for sensitive biomarkers of acute cytotoxicity of potential contaminants in aquatic systems. The detection of the potential acute toxicity of a pollutant is of interest because pulse discharges of contaminants to natural waters could lead to high concentrations of these substances that are only present for short periods of time but can affect aquatic organisms such as microalgae. Physiological alterations in C. moewusii cells were analysed after 1h of exposure to different concentrations of the herbicide paraquat. Cell viability was not affected, but the acute toxicity of paraquat was evident at other levels of cell physiology. Herbicide-treated cells showed lower autofluorescence and higher size and internal complexity, lower esterase activity and lower mitochondrial membrane potential. Paraquat induced the depolarisation of the plasma membrane and the increase of intracellular free calcium level and cytosolic pH in a concentration-dependent percentage of cells. All these effects can be related to the oxidative stress induced by the herbicide, as revealed the significantly increased intracellular levels of reactive oxygen species in cultures exposed to paraquat concentrations which induced the physiological alterations mentioned above. Excluding cell viability and mitochondrial membrane potential, these cytotoxicity endpoints could be considered sensitive biomarkers for the short-term exposure to pollutants such as herbicides.

Flow cytometric analysis to evaluate physiological alterations in herbicide-exposed Chlamydomonas moewusii cells.

Investigation of herbicide toxicology in non-target aquatic primary producers such as microalgae is of great importance from an ecological point of view. In order to study the toxicity of the widely used herbicide paraquat on freshwater green microalga Chlamydomonas moewusii, physiological changes associated with 96 h-exposures to this pollutant were monitored using flow cytometry (FCM) technique. Intracellular reactive oxygen species concentration, cytoplasmic membrane potential, metabolic activity and cell protein content were monitored to evaluate the toxicological impact of paraquat on algal physiology. Results showed that herbicide paraquat induced oxidative stress in C. moewusii cells, as it indicated the increase of both superoxide anion and hydrogen peroxide levels observed in non-chlorotic cells of cultures exposed to increasing herbicide concentrations. Furthermore, a progressive increase in the percentage of depolarised cells and a decrease in the metabolic activity level were observed in response to paraquat when non-chlorotic cells were analysed. Chlorotic cells were probably non-viable cells, based on the cytoplasmic membrane depolarisation, its metabolically non-active state and its drastically reduced protein content. In view of the obtained results, we have concluded that a range of significant physiological alterations, detected by flow cytometry, occur when C. moewusii, an ubiquitous microalga in freshwater environments, is challenged with environmentally relevant concentrations of the herbicide paraquat.