RESUMO
Estuarine coastal water and sediments collected from multiple locations within the middle Río de la Plata (RDLP) estuary were analyzed in order to identify the presence of microplastics (MPs, <5 mm) and mesoplastics (MePs, 5-25 mm) in one of the most significant estuaries in the Southwestern Atlantic. The present study represents one of the first researches to survey MPs and MePs contamination in key stations at RDLP estuary. Average concentrations of 14.17 ± 5.50 MPs/L and 10.00 MePs/L were detected in water samples, while 547.83 ± 620.06 MPs/kg (dry weight) and 74.23 ± 47.29 MePs/kg d.w. were recorded in sediments. The greatest abundances were observed in the more anthropized areas, near urban settlements. Fibers were the most conspicuous plastic items in water and sediments, followed by fragments. On the other hand, surface sediments, and 50 cm and 100 cm-depth sediments also presented MPs and MePs indicating they could serve as a stratigraphic indicator for recently formed sediments. The main polymer type identified were acrylic fibers, followed by polypropylene (PP) and polyethylene terephthalate (PET). Besides, SEM-EDX detected the presence of Si, Fe, Ti, Al and Cl onto the plastics' surface. These elements may serve as additives to enhance the plastics' properties, such as in the case of Ti, or they could originate from the environment, like biogenic Si or Fe, and Al possibly as a component of the suspended particles or sediments adhered to the micro or meso plastics. Finally, the results of the present study showed that MPs and MePs are commonly found in waters and also tend to be trapped in sediments of the RDLP estuary supporting the assertion that these areas play a substantial role in influencing the transport, dispersion, and buildup of MPs in estuarine regions.
RESUMO
In this study, we surveyed the presence of personal protective equipment (PPE) waste on the streets of Bogotá-Colombia, Lima-Perú, and Mar del Plata-Argentina. Furthermore, this work is also focused on the release capacity of Ag, Cu, and Zn metals associated with nanoparticles, and microplastics (MPs) from textile face masks (TFMs) and disposable face masks. According to our results, an association between low-income areas and PPE waste was found, which may be related to the periodicity of waste collection and economic activity. Polymers, like polypropylene, cotton-polyester, and additives, such as CaCO3, MgO, and Ag/Cu as nanoparticles, were identified. TFMs released high levels of Cu (35,900-60,200 µg·L-1), Zn (2340-2380 µg·L-1), and MPs (4528-10,640 particles/piece). Metals associated with nanoparticles leached by face masks did not present any antimicrobial activity against P. aeruginosa. Our study suggests that TFMs may leach large amounts of polluting nano/micromaterials in aquatic environments with potential toxicological effects on organisms.
Assuntos
Metais Pesados , Nanopartículas , Microplásticos , Máscaras , Plásticos , Cidades , Metais Pesados/análise , Equipamento de Proteção Individual , América do SulRESUMO
Hyaluronic acid (HA) and gelatin (Gel) are major components of the extracellular matrix of different tissues, and thus are largely appealing for the construction of hybrid hydrogels to combine the favorable characteristics of each biopolymer, such as the gel adhesiveness of Gel and the better mechanical strength of HA, respectively. However, despite previous studies conducted so far, the relationship between composition and scaffold structure and physico-chemical properties has not been completely and systematically established. In this work, pure and hybrid hydrogels of methacroyl-modified HA (HAMA) and Gel (GelMA) were prepared by UV photopolymerization and an extensive characterization was done to elucidate such correlations. Methacrylation degrees of ca. 40% and 11% for GelMA and HAMA, respectively, were obtained, which allows to improve the hydrogels' mechanical properties. Hybrid GelMA/HAMA hydrogels were stiffer, with elastic modulus up to ca. 30 kPa, and porous (up to 91%) compared with pure GelMA ones at similar GelMA concentrations thanks to the interaction between HAMA and GelMA chains in the polymeric matrix. The progressive presence of HAMA gave rise to scaffolds with more disorganized, stiffer, and less porous structures owing to the net increase of mass in the hydrogel compositions. HAMA also made hybrid hydrogels more swellable and resistant to collagenase biodegradation. Hence, the suitable choice of polymeric composition allows to regulate the hydrogels´ physical properties to look for the most optimal characteristics required for the intended tissue engineering application.
Assuntos
Materiais Biocompatíveis/química , Gelatina/química , Ácido Hialurônico/química , Hidrogéis/química , Metacrilatos/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Humanos , Polímeros/químicaRESUMO
La prevalencia de lactancia materna exclusiva hasta el sexto mes de edad en Chile no supera el 60%, a pesar de la promulgación de la Ley de Descanso Postnatal Parental el año 2011, la cual permite a las madres permanecer con el recién nacido hasta las veinticuatro semanas de vida. El objetivo de este trabajo fue explorar, desde la perspectiva de las madres, cuales son los aspectos involucrados en la duración del periodo de lactancia materna exclusiva. Sujetos y Métodos: Exploración cualitativa desde la teoría fundamentada. Se realizaron entrevistas semiestructuradas a 35 participantes y cinco grupos focales con 30, en total 65 madres trabajadoras participaron en el estudio. Se realizó un análisis de contenido inductivo, utilizando el software atlas ti-6.2. Los criterios de validez incluyeron triangulación por investigador y por técnica. Resultados: Los elementos identificados como favorecedores de la lactancia materna son la duración del período del descanso postnatal, el apoyo de la pareja, de la familia y de los profesionales de salud. Los que representan una barrera son la presencia de dolor al amamantar y la decisión de destetar precozmente, la cual puede estar influenciada por familiares o profesionales de la salud. Conclusiones: Dado la fuerte dependencia de factores como la pareja y la familia en la mantención de la lactancia materna, se propone que los profesionales de salud involucrados consideren estos aspectos en la promoción.
The prevalence of exclusive breastfeeding up to the sixth month of age does not exceed 60% in Chile, despite the enactment in 2011 of the Parental Leave Law, which entitles mothers to stay with the newborn up to the twenty-fourth week of life. Given the above, the aim of this study was to explore, from mothers' perspective, which are the aspects involved on the length of the Exclusive Breastfeeding Period. Subjects and method: Qualitative Exploration using a grounded theory approach. Semi-structured interviews and five focusgroups were conducted with 35 and30participants respectively; therefore a total of 65 working mothers took part in the study. Inductive content analysis was performed using atlas ti-6.2 software package. Validity criteria included triangulation by research and by technique. Results: The elements identified as encouraging breastfeeding are the length of maternal leave and the support of the couple, family and health professionals. Those representing barriers were the presence of breastfeeding-induced pain and early weaning decision, which might be influenced by family or health professionals. Conclusions: Given the strong dependence of factors such aspartner and family on breastfeeding maintenance, it is suggested that the involved health professionals shall consider these aspects in promotion.
Assuntos
Humanos , Apoio Social , Mulheres Trabalhadoras , Aleitamento Materno , Licença Parental , Promoção da Saúde , Hospitais PúblicosRESUMO
Models of basal ganglia (BG) function posit a dynamic balance between two classes of striatal projection neurons (SPNs): direct pathway neurons (dSPNs) that facilitate movements, and indirect pathway neurons (iSPNs) that repress movement execution. Two main modulatory transmitters regulate the output of these neurons: dopamine (DA) and acetylcholine (ACh). dSPNs express D1-type DA, M1-and M4-type ACh receptors, while iSPNs express D2-type DA and M1-type ACh receptors. Actions of M1-, D1-, and D2-receptors have been extensively reported, but we still ignore most actions of muscarinic M4-type receptors. Here, we used whole-cell recordings in acutely dissociated neurons, pharmacological tools such as mamba-toxins, and BAC D(1 or 2)-eGFP transgenic mice to show that activation of M4-type receptors with bath applied muscarine enhances Ca(2+)-currents through CaV1-channels in dSPNs and not in iSPNs. This action increases excitability of dSPNs after both direct current injection and synaptically driven stimulation. The increases in Ca(2+)-current and excitability were blocked specifically by mamba toxin-3, suggesting mediation via M4-type receptors. M4-receptor activation also increased network activity of dSPNs but not of iSPNs as seen with calcium-imaging techniques. Moreover, actions of D1-type and M4-type receptors may add to produce a larger enhancement of excitability of dSPNs or, paradoxically, oppose each other depending on the order of their activation. Possible implications of these findings are discussed.
Assuntos
Corpo Estriado/citologia , Vias Neurais/fisiologia , Neurônios/fisiologia , Receptor Muscarínico M4/metabolismo , Acetilcolina/farmacologia , Animais , Bloqueadores dos Canais de Cálcio/farmacologia , Células Cultivadas , Dopamina/farmacologia , Técnicas In Vitro , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/genética , Camundongos , Camundongos Transgênicos , Vias Neurais/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Nicardipino/farmacologia , Receptores de Dopamina D1/genética , Receptores de Dopamina D2/genética , Bloqueadores dos Canais de Sódio/farmacologia , Tetrodotoxina/farmacologiaRESUMO
La placenta, anexo embrionario propio de los mamíferos placentados, imprescindible para la supervivencia embriofetal, está formada por la zona más superficial del endometrio y el corion, asociado con el saco vitelino o el alantoides, dependiendo de la especie. La placenta provee el intercambio gaseoso y nutricio entre la madre y el feto, secreta hormonas y posee propiedades inmunosupresoras. Existen diferentes criterios para clasificar la placenta; de acuerdo a la distribución de las vellosidades coriales de la placenta: difusa, cotiledonaria, zonaria y discoidal; de acuerdo a las características histológicas de la placenta: epiteliocorial, sindesmocorial, endoteliocorial y hemocorial.
The placenta is an extraembryonic membrane of placental mammals, essential for embryo survival. It is formed by the most superficial zone of the endometrium and the chorion, associated with the yolk sac or allantois, depending on the species. The placenta provides gas and nutrient exchange between mother and fetus, secretes hormones and has immunosuppressive properties. There are different criteria to classify the placenta; i. e. according to the distribution of the chorionic villi of the placenta: diffuse, cotyledonary, zonaria and discoidal; according to the histological characteristics of the placenta: epitheliochorial, syndesmochorial, endotheliochorial and hemocorial.
Assuntos
Humanos , Animais , Feminino , Placenta/anatomia & histologia , Anatomia Comparada , Histologia ComparadaRESUMO
The loss of dopaminergic neurons in the substantia nigra compacta followed by striatal dopamine depletion is a hallmark of Parkinson's disease. After dopamine depletion, dopaminergic D(2) receptor (D(2)R)-class supersensitivity develops in striatal neurons. The supersensitivity results in an enhanced modulation of Ca(2+) currents by D(2)R-class receptors. However, the relative contribution of D(2)R, D(3)R, and D(4)R types to the supersensitivity, as well as the mechanisms involved, have not been elucidated. In this study, whole cell voltage-clamp recordings were performed to study Ca(2+) current modulation in acutely dissociated striatal neurons obtained from rodents with unilateral 6-hydroxydopamine lesions in the substantia nigra compacta. Selective antagonists for D(2)R, D(3)R, and D(4)R types were used to identify whether the modulation by one of these receptors experiences a selective change after dopaminergic denervation. It was found that D(3)R-mediated modulation was particularly enhanced. Increased modulation targeted Ca(V)2.1 (P/Q) Ca(2+) channels via the depletion of phosphatidylinositol 4,5-bisphosphate, an intracellular signaling cascade hard to detect in control neurons and hypothesized as being amplified by dopamine depletion. An imbalance in the striatal expression of D(3)R and its splice variant, D(3)nf, accompanied enhanced D(3)R activity. Because Ca(V)2.1 Ca(2+) channels mediate synaptic GABA release from the terminals of striatal neurons, reinforcement of their inhibition by D(3)R may explain in part the profound decrease in synaptic strength in the connections among striatal projection neurons observed in the dopamine-depleted striatum.
Assuntos
Canais de Cálcio Tipo N/fisiologia , Corpo Estriado/metabolismo , Dopamina/metabolismo , Fosfoinositídeo Fosfolipase C/deficiência , Receptores de Dopamina D2/biossíntese , Receptores de Dopamina D3/fisiologia , Animais , Masculino , Camundongos , Camundongos Transgênicos , Ratos , Ratos Wistar , Transdução de Sinais/fisiologia , Simpatectomia/métodos , Regulação para Cima/fisiologiaRESUMO
In adult neostriatal projection neurons, the intracellular Ca(2+) supplied by Ca(V)2.1 (P/Q) Ca(2+) channels is in charge of both the generation of the afterhyperpolarizing potential (AHP) and the release of GABA from their synaptic terminals, thus being a major target for firing pattern and transmitter release modulations. We have shown that activation of muscarinic M(1)-class receptors modulates Ca(V)2.1 channels in these neurons in rats. This modulation is reversible, is not membrane delimited, is blocked by the specific M(1)-class muscarinic antagonist muscarine toxin 7 (MT-7), and is neither mediated by protein kinase C (PKC) nor by protein phosphatase 2B (PP-2B). Hence, the signaling mechanism of muscarinic Ca(V)2.1 channel modulation has remained elusive. The present paper shows that inactivation of phospholipase C (PLC) abolishes this modulation while inhibition of phosphoinositide kinases, PI-3K and PI-4K, prevents its reversibility, suggesting that the reconstitution of muscarinic modulation depends on phosphoinositide rephosphorylation. In support of this hypothesis, the supply of intracellular phosphatidylinositol (4,5) bisphosphate [PI(4,5)P(2)] blocked all muscarinic modulation of this channel. The results indicate that muscarinic M(1) modulation of Ca(V)2.1 Ca(2+) channels in these neurons involves phosphoinositide hydrolysis.
Assuntos
1-Fosfatidilinositol 4-Quinase/metabolismo , Canais de Cálcio Tipo N/metabolismo , Neostriado/metabolismo , Neurônios/metabolismo , Receptor Muscarínico M1/metabolismo , Animais , Calcineurina/metabolismo , Canais de Cálcio/metabolismo , Células Cultivadas , Venenos Elapídicos/farmacologia , Hidrólise , Espaço Intracelular/metabolismo , Potenciais da Membrana/efeitos dos fármacos , Neostriado/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Técnicas de Patch-Clamp , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosforilação , Proteína Quinase C/metabolismo , Ratos , Receptor Muscarínico M1/antagonistas & inibidores , Fosfolipases Tipo C/antagonistas & inibidores , Fosfolipases Tipo C/metabolismoRESUMO
Objetivo. Determinar la presencia de parásitos en el blanquillo Sorubim cuspicaudus. Materiales y métodos. Se utilizaron 33 peces recolectados entre abril y diciembre de 2007, posteriormente llevados al laboratorio para reconocimiento externo e interno, y disección e inspección de la cavidad visceral. Los nemátodos encontrados fueron preservados en glicerina formalada al 5%, posteriormente fueron aclarados, visualizándose las estructuras internas para la merística e identificación con base en claves morfométricas. Para la microscopía de barrido (JEOL JSM-5910LV a un voltaje de aceleración de 15 kV) los parásitos fueron transferidos a formaldehído al 4% y luego fijados en tetraóxido de osmio, deshidratados con series de etanol y cubiertos con una película de oro (6-8nm) por electrodeposición (Denton Vacuum Desk II). Resultados. Los nemátodos fueron hallados solamente en la cavidad visceral e identificados como Contracaecum sp., en estado larval III, de color blanquecino, dos labios en el extremo anterior, un diente cuticular cónico y ligeramente romo. El extremo posterior es cónico, con dos glándulas anexas, ano y mucrón; la cola post-anal larga y sin espina terminal. La prevalencia de este parásito fue del 96.9% y en todos los casos la infestación fue leve. Del total de ejemplares analizados; los machos (n=9) presentaron intensidad parasitaria de 24.88±18.70 parásitos/pez; mientras que las hembras (n=24) presentaron una intensidad parasitaria de 69.52±22.77 parásitos/pez. Conclusiones. Contracaecum sp. se encuentra en cavidad visceral de blanquillo en estado larval III.
Assuntos
Peixes , Rios , ColômbiaRESUMO
La larvicultura de peces neotropicales altriciales presenta limitaciones para el manejo de la primera alimentación dado el pobre desarrollo del tracto digestivo y capacidad natatoria. La alimentación de la larva debe considerar el tamaño, densidad y calidad de la presa ofrecida. Este documento revisa a la luz de recientes trabajos la incidencia del zooplancton en la larvicultura de peces, aborda la importancia de la larvicultura en el proceso piscícola, la importancia del zooplancton como alimento y las alternativas en el manejo de cladóceros, copépodos y rotíferos para la alimentación de larvas de especies neotropicales.