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1.
Br J Nurs ; 28(21): 1394-1398, 2019 Nov 28.
Artículo en Inglés | MEDLINE | ID: mdl-31778343

RESUMEN

A coaching pilot was developed following the publication of a number of reports that recommended a review into how student nurses are taught in clinical practice. A bespoke version of the Collaborative Learning in Practice (CLiP) model was developed, which used both coaching and peer learning to encourage students to lead the delivery of care for a designated group of patients. A senior student led a team consisting of two junior students and they were given the responsibility of directing and coordinating the team in the manner expected of a registered nurse. A qualified nurse was responsible for the supervision of the students and used a coaching approach to teach. Findings from an evaluation revealed that the students benefitted from being able to work autonomously and were able to enhance their leadership and management skills.


Asunto(s)
Docentes de Enfermería/psicología , Relaciones Interprofesionales , Tutoría/métodos , Personal de Enfermería/psicología , Estudiantes de Enfermería/psicología , Grupos Focales , Humanos , Aprendizaje , Investigación en Educación de Enfermería , Investigación en Evaluación de Enfermería , Investigación Metodológica en Enfermería
2.
Aquat Toxicol ; 105(3-4): 535-42, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21924698

RESUMEN

The accumulation and toxicity of aluminium in freshwater organisms have primarily been examined following aqueous exposure. This study investigated the uptake, excretion and toxicity of aluminium when presented as aluminium-contaminated food. Adult Pacifastacus leniusculus were fed control (3 µg aluminium/g) or aluminium-spiked pellets (420 µg aluminium/g) over 28 days. Half the crayfish in each group were then killed and the remainder fed control pellets for a further 10 days (clearance period). Concentrations of aluminium plus the essential metals calcium, copper, potassium and sodium were measured in the gill, hepatopancreas, flexor muscle, antennal gland (kidney) and haemolymph. Histopathological analysis of tissue damage and sub-cellular distribution of aluminium were examined in the hepatopancreas. Haemocyte number and protein concentration in the haemolymph were analysed as indicators of toxicity. The hepatopancreas of aluminium-fed crayfish contained significantly more aluminium than controls on days 28 and 38, and this amount was positively correlated with the amount ingested. More than 50% of the aluminium in the hepatopancreas of aluminium-fed crayfish was located in sub-cellular fractions thought to be involved in metal detoxification. Aluminium concentrations were also high in the antennal glands of aluminium-fed crayfish suggesting that some of the aluminium lost from the hepatopancreas is excreted. Aluminium exposure via contaminated food caused inflammation in the hepatopancreas but did not affect the number of circulating haemocytes, haemolymph ion concentrations or protein levels. In conclusion, crayfish accumulate, store and excrete aluminium from contaminated food with only localised toxicity.


Asunto(s)
Aluminio/toxicidad , Astacoidea/efectos de los fármacos , Contaminación de Alimentos , Hepatopáncreas/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Aluminio/farmacocinética , Animales , Astacoidea/metabolismo , Hemolinfa/química , Hepatopáncreas/química , Hepatopáncreas/patología , Fracciones Subcelulares , Pruebas de Toxicidad Aguda , Contaminantes Químicos del Agua/farmacocinética
3.
Sci Total Environ ; 409(24): 5277-83, 2011 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-21937086

RESUMEN

Extension of the conditions under which Al toxicity is tested is required. Environmentally representative preparation of waters is used in investigating roles of alginate (AA) and humic acids (HA) in partitioning of Al (0.5 mg L(-1)), subsequent uptake and accumulation by and toxicity to Lymnaea stagnalis. HA and AA did not alter precipitation of Al(OH)3, but altered subsequent behaviour of Al. High (40 mg L(-1)) HA concentrations, and to a lesser extent AA, prevented settling and availability for benthic grazing but made deposited Al more likely to be ingested. HA detoxified but AA increased toxicity relative to Al alone. Low concentration (4 mg L(-1)) AA and HA do not change partitioning but increase uptake; they both detoxify, but AA less than HA. The study shows OC:Al ratio is critical in predicting Al behaviour in natural waters, also uptake is mediated by snail behaviour, not solely a function of concentration and form of Al. Therefore, predicting Al behaviour will be subject to errors in determining relevant water composition and response of biota to the new speciation. However, with respect to toxicity, rather than other aspects of Al behaviour, different ratios of HA and Al are insignificant compared to whether AA is present rather than HA.


Asunto(s)
Aluminio/farmacocinética , Aluminio/toxicidad , Lymnaea/efectos de los fármacos , Contaminantes Químicos del Agua/farmacocinética , Contaminantes Químicos del Agua/toxicidad , Alginatos/análisis , Alginatos/farmacología , Animales , Disponibilidad Biológica , Agua Dulce/química , Ácido Glucurónico/análisis , Ácido Glucurónico/farmacología , Ácidos Hexurónicos/análisis , Ácidos Hexurónicos/farmacología , Sustancias Húmicas/análisis , Lymnaea/fisiología , Distribución Tisular
4.
Aquat Toxicol ; 99(1): 93-9, 2010 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-20451262

RESUMEN

The potential for trophic transfer of aluminium (Al) was investigated using a grazing detritivore, the freshwater snail Lymnaea stagnalis, and a predator, the signal crayfish Pacifastacus leniusculus. Snails were exposed to either aqueous Al (500 microg l(-1)) in the presence or absence of an inorganic ligand (phosphate (+P); 500 microg l(-1)) for 30 days, or kept as unexposed controls. Subcellular partitioning of Al in the snail tissues was characterised using ultracentrifugation. Al content in the soft tissues and the subcellular fractions was measured using inductively coupled plasma atomic emission spectroscopy. Exposed and control snails were fed to individually housed crayfish (n=6 per group) over 40 days. Water samples, uneaten snail tissue and faeces were collected throughout the experiment in order to assess the fate of Al. Behavioural toxicity to the crayfish was assessed at four time points, and tissue accumulation of Al in soft tissues was measured following a 2-day depuration period. Snails exposed to Al+P accumulated more Al per snail than those exposed to Al only (291 microg vs 206 microg), and also contained a higher proportion of detoxified Al (in inorganic granules and associated with heat stable proteins) (39% vs 26%). There were no significant differences in behavioural activity between the different groups of crayfish at any time point. Crayfish fed snails exposed to only Al accumulated significant levels of Al in their total soft tissues, compared to controls; crayfish fed Al+P-exposed snails did not, even though concentrations of Al in these snails were higher. The highest concentrations of Al were found in the green gland in both crayfish feeding groups, and the gut and hepatopancreas in crayfish fed Al only exposed snails; all of these were significantly higher than in crayfish fed control snails. There was no significant accumulation of Al in the gills or flexor muscle in any group. At least 17% of trophically available Al in the snail tissues was accumulated by the crayfish. This proportion was similar in both feeding groups but, as the proportion of trophically available Al in the snails exposed to Al+P was lower, this led to lower accumulation in the Al+P crayfish feeding group. This study indicates that in comparison to vertebrates, aquatic invertebrates accumulate a higher proportion of Al via oral ingestion but it does not accumulate in tissues that may pose a threat to human consumers.


Asunto(s)
Aluminio/metabolismo , Aluminio/toxicidad , Organismos Acuáticos/efectos de los fármacos , Cadena Alimentaria , Lymnaea/efectos de los fármacos , Contaminantes Químicos del Agua/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Organismos Acuáticos/metabolismo , Astacoidea/fisiología , Agua Dulce , Branquias/metabolismo , Lymnaea/metabolismo , Fosfatos/metabolismo , Fosfatos/toxicidad , Conducta Predatoria/fisiología , Espectrofotometría Atómica , Factores de Tiempo , Distribución Tisular
5.
Biometals ; 23(2): 221-30, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19937462

RESUMEN

Aluminum is a toxic metal whose complex aquatic chemistry, mechanisms of toxicity and trophic transfer are not fully understood. The only isotope of Al suitable for tracing experiments in organisms-(26)Al-is a rare, costly radioisotope with a low emission energy, making its use difficult. Gallium shares a similar chemistry with Al and was therefore investigated as a potential substitute for Al for use in aquatic organisms. The freshwater snail, Lymnaea stagnalis was exposed to either Al or Ga (0.0135 mM) under identical conditions for up to 40 days. Behavioural toxicity, metal accumulation in the tissues, and sub-cellular partitioning of the metals were determined. Al was more toxic than Ga and accumulated to significantly higher levels in the soft tissues (P < 0.05). The proportion of Al in the digestive gland (DG; detoxificatory organ) relative to other tissues was significantly lower than that of Ga (P < 0.05) from day 14 onwards. There were also differences in the proportions of Al and Ga associated with heat stable proteins (HSPs) in the digestive gland, with significantly more HSP present in the DGs of snails exposed to Al, but significantly less Al than Ga associated with the HSP per unit mass protein present. From this evidence, we conclude that Ga may be of limited use as a tracer for Al in animal systems.


Asunto(s)
Aluminio/metabolismo , Galio/metabolismo , Indicadores y Reactivos/metabolismo , Coloración y Etiquetado , Aluminio/toxicidad , Animales , Conducta Animal/efectos de los fármacos , Femenino , Agua Dulce , Galio/toxicidad , Indicadores y Reactivos/química , Lymnaea/anatomía & histología , Lymnaea/efectos de los fármacos , Lymnaea/metabolismo , Óvulo/efectos de los fármacos , Óvulo/fisiología , Coloración y Etiquetado/instrumentación , Coloración y Etiquetado/métodos , Fracciones Subcelulares/metabolismo , Distribución Tisular
6.
Environ Pollut ; 157(7): 2142-6, 2009 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-19285770

RESUMEN

The amount of toxic metal accumulated by an organism is often taken as an indicator of potential toxicity. We investigated this relationship in the freshwater snail, Lymnaea stagnalis, exposed to 500 microg l(-1) Al over 30 days, either alone or in the presence of phosphate (500 microg l(-1) P) or a fulvic acid surrogate (FAS; 10 mg l(-1) C). Behavioural activity was assessed and tissue accumulation of Al quantified. Lability of Al within the water column was a good predictor of toxicity. FAS increased both Al lability and behavioural dysfunction, whereas phosphate reduced Al lability, and completely abolished Al-induced behavioural toxicity. Tissue accumulation of Al was not linked to toxicity. Higher levels of Al were accumulated in snails exposed to Al + P, compared to those exposed to Al alone, whereas FAS reduced Al accumulation. These findings demonstrate that the degree of tissue accumulation of a metal can be independent of toxicity.


Asunto(s)
Aluminio/toxicidad , Lymnaea/metabolismo , Contaminantes Químicos del Agua/toxicidad , Aluminio/farmacocinética , Animales , Conducta Animal/efectos de los fármacos , Exposición a Riesgos Ambientales , Lymnaea/efectos de los fármacos , Distribución Tisular , Pruebas de Toxicidad Aguda , Contaminantes Químicos del Agua/farmacocinética
7.
Environ Sci Technol ; 42(6): 2189-94, 2008 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-18409657

RESUMEN

Silicon (Si) ameliorates aluminum (Al) toxicity to a range of organisms, but in almost all cases this is due to ex vivo Si-Al interactions forming inert hydroxyaluminosilicates (HAS). We hypothesized a Si-specific intracellular mechanism for Al detoxification in aquatic snails, involving regulation of orthosilicic acid [Si(OH)4]. However, the possibility of ex vivo formation and uptake of soluble HAS could not be ruled out Here we provide unequivocal evidence for Si-Al interaction in vivo, including their intracellular colocalization. In snails preloaded with Si(0H)4, behavioral toxicity in response to subsequent exposure to Al was abolished. Similarly, recovery from Al-induced toxicity was faster when Si(OH)4 was provided, together with rapid loss of Al from the major detoxificatory organ (digestive gland). Temporal separation of Al and Si exposure excluded the possibility of their interaction ex vivo. Elemental mapping using analytical transmission electron microscopy revealed nanometre-scale colocalization of Si and Al within excretory granules in the digestive gland, consistent with recruitment of Si(OH)4, followed by high-affinity Al binding to form particles similarto allophane, an amorphous HAS. Given the environmental abundance of both elements, we anticipate this to be a widespread phenomenon, providing a cellular defense against the profoundly toxic Al(III) ion.


Asunto(s)
Aluminio/toxicidad , Lymnaea/efectos de los fármacos , Ácido Silícico/metabolismo , Contaminantes Químicos del Agua/toxicidad , Animales , Sistema Digestivo/metabolismo , Sistema Digestivo/ultraestructura , Lymnaea/metabolismo , Lymnaea/ultraestructura , Lisosomas/metabolismo , Lisosomas/ultraestructura , Microscopía Electrónica de Transmisión
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