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1.
Toxicol Lett ; 388: 56-63, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37806367

RESUMO

Skin decontamination of Chemical Biological Radioactive and Nuclear (CBRN) materials involves the timely and effective removal of the contaminants from the skin surface. The current work evaluated Fuller's Earth & The Reactive Skin Decontaminant Lotion Kit (RSDL®) to investigate whether they were as efficacious against free base Carfentanil skin contamination as they are against chemical warfare agents. The in vitro methodology used allowed for evaluation of decontamination regimens as specified by the decontaminant manufacturer rather than as an application of a bolus dose left in situ for the study duration. A selection of novel decontaminants, including Dermal Decontamination Gel (DDGel), Trivorex®, itaconic acid (IA), N,N'-methylenebisacrylamide (MBA), 2-trifluoromethylacrylic acid (TFMAA) and NanoSan Sorb were also tested for efficacy. All the evaluated decontaminants were successful at removing the majority of the Carfentanil skin surface contamination. The current work has shown that the Fuller's Earth decontamination kit, removes as much (or more) free base carfentanil from the skin surface in comparison to other products tested in this study series.


Assuntos
Substâncias para a Guerra Química , Absorção Cutânea , Descontaminação/métodos , Pele , Substâncias para a Guerra Química/metabolismo
2.
Toxicol In Vitro ; 72: 105100, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33493622

RESUMO

Carfentanil is a synthetic opioid restricted to veterinary use due to its potency. Public health concerns have been raised as to the potential of carfentanil to exhibit toxicity after absorption via the percutaneous route following unintentional contamination. The current study measured the penetration of free base carfentanil through human, pig and rat skin using in vitro static diffusion cells. The human penetration rates were compared against literature toxicology values and indicated that, dependent on the contamination density, contamination area and residence time, skin decontamination and medical countermeasures may be required to ameliorate toxicity. The pig and rat skin penetration data will form the basis of future work to develop relevant in silico and in vivo models to further elucidate likely toxic effects and the medical strategies to mitigate against them.


Assuntos
Analgésicos Opioides/metabolismo , Fentanila/análogos & derivados , Absorção Cutânea , Pele/metabolismo , Administração Cutânea , Animais , Fentanila/metabolismo , Humanos , Técnicas In Vitro , Permeabilidade , Ratos Sprague-Dawley , Suínos
3.
Toxicol In Vitro ; 53: 121-125, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30099087

RESUMO

The in vitro percutaneous penetration of the nerve agent VX through pig skin was measured in the absence and presence of water or artificial sweat to determine the impact such conditions might have on penetration rates. Experiments were performed with Franz-type glass diffusion cells containing dermatomed pig skin as a surrogate for human skin. The receptor fluid used was 50% aqueous ethanol. 14C labelled VX was applied to the skin surface under infinite or finite dosing conditions with regular receptor fluid sampling up to 24 h. Penetration from aqueous solutions of VX showed the maximal steady state penetration rate (Jss) was from the 50% (v:v) solution (366 ±â€¯149 µg·cm-2·h-1), this being ~2.2 fold greater than Jss measured for neat VX (169 ±â€¯89 µg·cm-2·h-1). Application of neat VX to water-wetted skin was also found to result in an increased penetration rate, compared to dry skin, shortly after contamination. These studies have shown that, in vitro, aqueous solutions of VX in contact with the skin can result in increased penetration rates when compared to neat VX applied to dry skin.


Assuntos
Agentes Neurotóxicos/metabolismo , Compostos Organotiofosforados/metabolismo , Absorção Cutânea , Pele/metabolismo , Animais , Difusão , Técnicas In Vitro , Agentes Neurotóxicos/química , Compostos Organotiofosforados/química , Suor/química , Suínos , Água/química
4.
Ecology ; 99(3): 681-689, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29315539

RESUMO

Predators can alter nutrient cycles simply by inducing stress in prey. This stress accelerates prey's protein catabolism, nitrogen waste production, and nitrogen cycling. Yet predators also reduce the feeding rates of their prey, inducing food deprivation that is expected to slow protein catabolism and nitrogen cycling. The physiology of prey under predation risk thus balances the influences of predation risk and food deprivation, and this balance is central to understanding the role of predators in nutrient cycles. We explored the separate and combined effects of predation risk and food deprivation on prey physiology and nutrient cycling by exposing guppies (Poecilia reticulata) to predation risk and food deprivation in a 2 × 2 design. We simulated predation risk using chemical cues from a natural predator of guppies, and we created food deprivation by rationing food availability. We measured guppy response as food consumption, growth, tissue energy density, tissue carbon:nitrogen, and nitrogen (N) excretion and assimilation. We found that N-linked physiological processes (N consumption, assimilation, excretion) were strongly affected by predation risk, independent of food consumption. Guppies excreted substantially less under predation risk than they did under food deprivation or control conditions. These results suggest that predation risk, per se, triggers physiological changes in guppies that increase N retention and decrease N excretion. We suggest that slower N metabolism under predation risk is an adaptive response that minimizes protein loss in the face of predictable, predator-induced food restriction. Notably, N metabolism shares common hormonal control with food seeking behavior, and we speculate that increased N retention is a direct and immediate result of reduced food seeking under predation risk. Contrary to predation-stress-based hypotheses for how predators affect nutrient cycling by prey, our result indicates that even short-term exposure to predators may decelerate, rather than accelerate, the speed of N cycling by suppressing N turnover by prey.


Assuntos
Cadeia Alimentar , Privação de Alimentos , Animais , Jejum , Medo , Nitrogênio , Comportamento Predatório
5.
Cutan Ocul Toxicol ; 37(2): 172-179, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28853336

RESUMO

PURPOSE: The aim of this study was to evaluate a candidate haemostat (WoundStat™), down-selected from previous in vitro studies, for efficacy as a potential skin decontaminant against the chemical warfare agent pinacoyl methylfluorophosphonate (Soman, GD) using an in vivo pig model. MATERIALS AND METHODS: An area of approximately 3 cm2 was dermatomed from the dorsal ear skin to a nominal depth of 100 µm. A discrete droplet of 14C-GD (300 µg kg-1) was applied directly onto the surface of the damaged skin at the centre of the dosing site. Animals assigned to the treatment group were given a 2 g application of WoundStat™ 30 s after GD challenge. The decontamination efficacy of WoundStat™ against GD was measured by the direct quantification of the distribution of 14C-GD, as well as routine determination of whole blood cholinesterase and physiological measurements. RESULTS: WoundStat™ sequestered approximately 70% of the applied 14C-GD. Internal radiolabel recovery from treated animals was approximately 1% of the initially applied dose. Whole blood cholinesterase levels decreased to less than 10% of the original value by 15 min post WoundStat™ treatment and gradually decreased until the onset of apnoea or until euthanasia. All treated animals showed signs of GD intoxication that could be grouped into early (mastication, fasciculations and tremor), intermediate (miosis, salivation and nasal secretions) and late onset (lacrimation, body spasm and apnoea) effects. Two of the six WoundStat™ treated animals survived the study duration. CONCLUSIONS: The current study has shown that the use of WoundStat™ as a decontaminant on damaged pig ear skin was unable to fully protect against GD toxicity. Importantly, the findings indicate that the use of WoundStat™ in GD contaminated wounds would not exacerbate GD toxicity. These data suggest that absorbent haemostatic products may offer some limited functionality as wound decontaminants.


Assuntos
Substâncias para a Guerra Química/farmacocinética , Inibidores da Colinesterase/farmacocinética , Descontaminação/métodos , Absorção Cutânea , Soman/farmacocinética , Animais , Substâncias para a Guerra Química/toxicidade , Inibidores da Colinesterase/toxicidade , Colinesterases/sangue , Feminino , Pele/metabolismo , Soman/toxicidade , Suínos , Distribuição Tecidual
6.
J Appl Toxicol ; 38(3): 318-328, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29023806

RESUMO

This study used a damaged skin, porcine model to evaluate the in vivo efficacy of WoundStat™ for the decontamination of superficial, nerve agent-contaminated wounds. Anaesthetized animals were randomly assigned to either control (n = 7), no decontamination (n = 12) or WoundStat™ (n = 12) treatment groups. Pigs were exposed to a 5× LD50 dose of neat, radiolabelled S-[2-(diisopropylamino)ethyl]-O-ethyl methyl-phosphonothioate (VX; or equivalent volume of sterile saline for the control group) via an area of superficially damaged skin on the ear. WoundStat™ was applied at 30 seconds post-exposure to assigned animals. The VX contaminant (or saline) and decontaminant remained in place for the duration of the study (up to 6 hours). Physiological parameters and signs of intoxication were recorded during the exposure period. Skin and organ samples were taken post mortem for 14 C-VX distribution analyses. Blood samples were taken periodically for toxicokinetic and whole-blood acetylcholinesterase (AChE) activity analyses. VX exposure was accompanied by a rapid decrease in AChE activity in all animals, regardless of decontamination. However, decontamination significantly improved survival rate and time and reduced the severity of signs of intoxication. In addition, the distribution of 14 C-VX in key internal organs and post mortem blood samples was significantly lower in the WoundStat™ treatment group. This study demonstrates that WoundStat™ may be a suitable medical countermeasure for increasing both survival rate and time following VX exposure. The results also suggest that AChE activity is not a useful prognostic indicator.


Assuntos
Substâncias para a Guerra Química/toxicidade , Inibidores da Colinesterase/toxicidade , Descontaminação/métodos , Hemostáticos/administração & dosagem , Compostos Organotiofosforados/toxicidade , Silicatos/administração & dosagem , Pele/efeitos dos fármacos , Ferimentos Penetrantes/tratamento farmacológico , Acetilcolinesterase/sangue , Administração Cutânea , Administração Tópica , Animais , Biomarcadores/sangue , Substâncias para a Guerra Química/farmacocinética , Inibidores da Colinesterase/administração & dosagem , Inibidores da Colinesterase/sangue , Inibidores da Colinesterase/farmacocinética , Feminino , Compostos Organotiofosforados/administração & dosagem , Compostos Organotiofosforados/sangue , Compostos Organotiofosforados/farmacocinética , Pele/lesões , Pele/metabolismo , Absorção Cutânea , Sus scrofa , Distribuição Tecidual , Ferimentos Penetrantes/sangue
7.
PLoS One ; 12(11): e0187931, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29176898

RESUMO

In many contexts, nutrient excretion by consumers can impact ecosystems by altering the availability of limiting nutrients. Variation in nutrient excretion can be predicted by mass balance models, most of which are premised on two key ideas: (1) consumers maintain fixed whole-body nutrient content (i.e., %N and %P), so-called fixed homeostasis; (2) if dietary nutrients are not matched to whole-body nutrients, excesses of any nutrient are released as excretion to maintain fixed homeostasis. Mass balance models thus predict that consumer excretion should be positively correlated with diet nutrients and negatively correlated with whole-body nutrients. Recent meta-analyses and field studies, however, have often failed to find these expected patterns, potentially because of a confounding influence-flexibility in whole-body nutrient content with diet quality (flexible homeostasis). Here, we explore the impact of flexible homeostasis on nutrient excretion by comparing the N and P excretion of four genetically diverged Trinidadian guppy (Poecilia reticulata) populations when reared on diets of variable P content. As predicted by mass balance, P excretion increased on the high-P diet, but, contrary to the notion of fixed homeostasis, guppy whole-body %P also increased on the high-P diet. While there was no overall correlation between excretion nutrients and whole-body nutrients, when the effect of diet on both whole-body and excretion nutrients was included, we detected the expected negative correlation between whole-body N:P and excretion N:P. This last result suggests that mass balance can predict excretion rates within species, but only if dietary effects on whole-body nutrient content are controlled. Flexible homeostasis can obscure patterns predicted by mass balance, creating an imperative to accurately capture an organism's diet quality in predicting its excretion rate.


Assuntos
Dieta , Vertebrados/fisiologia , Animais , Modelos Biológicos , Nitrogênio/análise , Fósforo/análise , Análise de Sobrevida , Vertebrados/crescimento & desenvolvimento
8.
Sci Rep ; 7(1): 5770, 2017 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-28720857

RESUMO

Population variation in trophic niche is widespread among organisms and is of increasing interest given its role in both speciation and adaptation to changing environments. Trinidadian guppies (Poecilia reticulata) inhabiting stream reaches with different predation regimes have rapidly evolved divergent life history traits. Here, we investigated the effects of both predation and resource availability on guppy trophic niches by evaluating their gut contents, resource standing stocks, and δ15N and δ13C stable isotopes across five streams during the wet season. We found that guppies from low predation (LP) sites had a consistently higher trophic position and proportion of invertebrates in their guts and assimilate less epilithon than guppies from high predation (HP) sites. Higher trophic position was also associated with lower benthic invertebrate availability. Our results suggest that LP guppies could be more efficient invertebrate consumers, possibly as an evolutionary response to greater intraspecific competition for higher quality food. This may be intensified by seasonality, as wet season conditions can alter resource availability, feeding rates, and the intensity of intraspecific competition. Understanding how guppy diets vary among communities is critical to elucidating the role of niche shifts in mediating the link between environmental change and the evolution of life histories.


Assuntos
Dieta , Ecossistema , Poecilia/fisiologia , Comportamento Predatório/fisiologia , Adaptação Fisiológica/fisiologia , Animais , Evolução Biológica , Feminino , Geografia , Masculino , Dinâmica Populacional , Rios , Estações do Ano , Índias Ocidentais
9.
Ecology ; 98(5): 1475, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28263380

RESUMO

Animals can be important in modulating ecosystem-level nutrient cycling, although their importance varies greatly among species and ecosystems. Nutrient cycling rates of individual animals represent valuable data for testing the predictions of important frameworks such as the Metabolic Theory of Ecology (MTE) and ecological stoichiometry (ES). They also represent an important set of functional traits that may reflect both environmental and phylogenetic influences. Over the past two decades, studies of animal-mediated nutrient cycling have increased dramatically, especially in aquatic ecosystems. Here we present a global compilation of aquatic animal nutrient excretion rates. The dataset includes 10,534 observations from freshwater and marine animals of N and/or P excretion rates. These observations represent 491 species, including most aquatic phyla. Coverage varies greatly among phyla and other taxonomic levels. The dataset includes information on animal body size, ambient temperature, taxonomic affiliations, and animal body N:P. This data set was used to test predictions of MTE and ES, as described in Vanni and McIntyre (2016; Ecology DOI: 10.1002/ecy.1582).


Assuntos
Organismos Aquáticos/metabolismo , Nitrogênio/metabolismo , Fósforo/metabolismo , Animais , Ecossistema , Água Doce , Filogenia
10.
J Appl Toxicol ; 37(9): 1036-1045, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28304107

RESUMO

This study used a damaged skin, porcine model to evaluate the in vivo efficacy of WoundStat™ for decontamination of superficial (non-haemorrhaging), sulphur mustard-contaminated wounds. The dorsal skin of 12 female pigs was subjected to controlled physical damage and exposed to 10 µL 14 C-radiolabelled sulphur mustard (14 C-SM). Animals were randomly assigned to either a control or a treatment group. In the latter, WoundStat™ was applied 30 s post exposure and left in situ for 1 h. Skin lesion progression and decontaminant efficacy were quantified over 6 h using a range of biophysical measurements. Skin, blood and organ samples were taken post mortem for histopathological assessment, 14 C-SM distribution and toxicokinetic analyses. Application of SM to damaged skin without decontamination was rapidly followed by advanced signs of toxicity, including ulceration and decreased blood flow at the exposure site in all animals. WoundStat™ prevented ulceration and improved blood flow at the exposure site in all decontaminated animals (n = 6). Furthermore, significantly smaller quantities of 14 C-SM were detected in the blood (45% reduction), and recovered from skin (70% reduction) and skin surface swabs (99% reduction) at 6 h post-challenge. Overall, the distribution of 14 C-SM in the internal organs was similar for both groups, with the greatest concentration in the kidneys, followed by the liver and small intestine. WoundStat™ significantly reduced the amount of 14 C-SM recovered from the liver, a key organ for SM metabolism and detoxification. This study demonstrates that WoundStat™ is a suitable product for reducing the ingress and toxicity of a chemical warfare agent. Copyright © 2017 John Wiley & Sons, Ltd.


Assuntos
Descontaminação , Gás de Mostarda/farmacocinética , Gás de Mostarda/toxicidade , Pele/efeitos dos fármacos , Animais , Substâncias para a Guerra Química/farmacocinética , Substâncias para a Guerra Química/toxicidade , Modelos Animais de Doenças , Feminino , Intestino Delgado/efeitos dos fármacos , Intestino Delgado/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Pele/patologia , Absorção Cutânea/efeitos dos fármacos , Suínos , Toxicocinética
11.
J Appl Toxicol ; 37(8): 976-984, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28218409

RESUMO

Previous studies have demonstrated that haemostatic products with an absorptive mechanism of action retain their clotting efficiency in the presence of toxic materials and are effective in decontaminating chemical warfare (CW) agents when applied to normal, intact skin. The purpose of this in vitro study was to assess three candidate haemostatic products for effectiveness in the decontamination of superficially damaged porcine skin exposed to the radiolabelled CW agents, soman (GD), VX and sulphur mustard (HD). Controlled physical damage (removal of the upper 100 µm skin layer) resulted in a significant enhancement of the dermal absorption of all three CW agents. Of the haemostatic products assessed, WoundStat™ was consistently the most effective, being equivalent in performance to a standard military decontaminant (fuller's earth). These data suggest that judicious application of haemostatic products to wounds contaminated with CW agents may be a viable option for the clinical management of casualties presenting with contaminated, haemorrhaging injuries. Further studies using a relevant animal model are required to confirm the potential clinical efficacy of WoundStat™ for treating wounds contaminated with CW agents. Copyright © 2017 John Wiley & Sons, Ltd.


Assuntos
Substâncias para a Guerra Química/toxicidade , Descontaminação/métodos , Hemostáticos/uso terapêutico , Pele/lesões , Ferimentos Penetrantes/tratamento farmacológico , Administração Tópica , Animais , Descoberta de Drogas , Feminino , Hemostáticos/administração & dosagem , Técnicas In Vitro , Masculino , Pele/efeitos dos fármacos , Absorção Cutânea , Sus scrofa
12.
J Vis Exp ; (111)2016 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-27214263

RESUMO

Nordic walking (NW) has become a safe and simple form of exercise in recent years, and in studying this gait pattern, various data collection techniques have been employed, each with positives and negatives. The aim was to determine the effect of NW on older adult gait and posture and to determine optimal use of different data collection systems in both short and long duration analysis. Gait and posture during NW and normal walking were assessed in 17 healthy older adults (age: 69 ± 7.3). Participants performed two trials of 6 Minute Walk Tests (6MWT) (1 with poles (WP) and 1 without poles (NP)) and 6 trials of a 5m walk (3 WP and 3 NP). Motion was recorded using two systems, a 6-sensor accelerometry system and an 8-camera 3-dimensional motion capture system, in order to quantify spatial-temporal, kinematic, and kinetic parameters. With both systems, participants demonstrated increased stride length and double support and decreased gait speed and cadence WP compared to NP (p <0.05). Also, with motion capture, larger single support time was found WP (p <0.05). With 3-D capture, smaller hip power generation and moments of force were found at heel contact and pre-swing as well as smaller knee power absorption at heel contact, pre-swing, and terminal swing WP compared to NP, when assessed over one cycle (p <0.05). Also, WP yielded smaller moments of force at heel contact and terminal swing along with larger moments at mid-stance of a gait cycle (p <0.05). No changes were found for posture. NW seems appropriate for promoting a normal gait pattern in older adults. Three-dimensional motion capture should primarily be used during short duration gait analysis (i.e. single gait cycle), while accelerometry systems should be primarily employed in instances requiring longer duration analysis such as during the 6MWT.


Assuntos
Marcha/fisiologia , Caminhada/fisiologia , Adulto , Idoso , Fenômenos Biomecânicos , Feminino , Humanos , Imageamento Tridimensional/métodos , Articulação do Joelho/fisiologia , Masculino , Pessoa de Meia-Idade , Fotogrametria/instrumentação , Postura/fisiologia , Amplitude de Movimento Articular
13.
J Aging Phys Act ; 24(4): 575-582, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27051072

RESUMO

The aim of this study was to investigate the impact of an 8-week Nordic walking (NW) intervention on older adult gait patterns and postural alignment. Twelve healthy older adults aged 60-80 years (8 female, 4 male) participated, all performing two 6-min walk tests (one with poles [WP], one without poles [NP]) and six 5-m walk trials (3 WP, 3 NP) at pre- and posttesting. Gait and postural variables were compared between poling conditions (i.e., WP to NP) as well as before and following the intervention. Following training, pole use resulted in various gait changes including: longer stride, faster gait, and increased power generation at the hip (H3) and power absorption at the knee (K1 and K4). We conclude that an initial 8-week training period is necessary for novice NW to perfect technique and to restore gait to a more natural, normal pattern following training.


Assuntos
Marcha/fisiologia , Postura/fisiologia , Teste de Caminhada , Idoso , Idoso de 80 Anos ou mais , Antropometria , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Amplitude de Movimento Articular/fisiologia
14.
Hum Mov Sci ; 47: 135-140, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26986766

RESUMO

OBJECTIVES: To assess the effects of voluntarily reducing postural sway on postural control and to determine the attention level needed to do so in healthy adults (n=16, 65.9±9.7) and persons with PD (n=25, 65.8±9.5 years). Tasks: quiet and still standing conditions with and without a category task. Cognitive performance, center of pressure (CoP) displacement variability (RMSCoP) and velocity (VCoP) were assessed in the anterior-posterior (AP) and medial-lateral (ML) directions. Controls showed larger RMSCoP (AP) and VCoP (AP and ML) during still versus quiet standing (p<0.01), while the PD group demonstrated no changes. In the PD group, RMSCoP and VCoP (ML) increased in still standing when performed with the cognitive task (p<0.05). In both groups, cognitive responses decreased in still standing (p<0.05). In PD, attempting to reduce postural sway did not affect postural control under single task conditions, however ML CoP variability and velocity did increase as a dual task. In older adults, increased displacement and velocity in both AP and ML directions was observed during single, but not dual task conditions. Therefore standing still might not be an adequate postural strategy as it increases the attentional demand and affects motor performance, putting persons with PD at greater risk for falls.


Assuntos
Atenção/fisiologia , Cognição , Doença de Parkinson/fisiopatologia , Equilíbrio Postural/fisiologia , Idoso , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
15.
Aging Clin Exp Res ; 28(5): 909-15, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26607957

RESUMO

To determine the effect of age on stepping performance and to compare the cognitive demand required to regulate repetitive stepping between older and younger adults while performing a stepping in place task (SIP). Fourteen younger (25.4 ± 6.5) and 15 older adults (71.0 ± 9.0) participated in this study. They performed a seated category fluency task and Stroop test, followed by a 60 s SIP task. Following this, both the cognitive and motor tasks were performed simultaneously. We assessed cognitive performance, SIP cycle duration, asymmetry, and arrhythmicity. Compared to younger adults, older adults had larger SIP arrhythmicity both as a single task and when combined with the Category (p < 0.001) and Stroop (p < 0.01) tasks. Older adults also had larger arrhythmicity when dual tasking compared to SIP alone (p < 0.001). Older adults showed greater SIP asymmetry when combined with Category (p = 0.006) and Stroop (p = 0.06) tasks. Finally, they had lower cognitive performance than younger adults in both single and dual tasks (p < 0.01). Age and type of cognitive task performed with the motor task affected different components of stepping. While SIP arrhythmicity was larger for all conditions in older compared to younger adults, cycle duration was not different, and asymmetry tended to be larger during SIP when paired with a verbal fluency task. SIP does not require a high level of control for dynamic stability, therefore demonstrating that higher-level executive function is necessary for the regulation of stepping activity independently of the regulation of postural balance. Furthermore, older adults may lack the cognitive resources needed to adequately regulate stepping activity while performing a cognitive task relying on the executive function.


Assuntos
Função Executiva/fisiologia , Equilíbrio Postural/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
16.
Toxicol In Vitro ; 30(1 Pt B): 454-61, 2015 Dec 25.
Artigo em Inglês | MEDLINE | ID: mdl-26391143

RESUMO

Diffusion cells are used to determine the penetration of chemicals through skin in vitro. The cells have a limited surface area defined by the edge of the donor chamber. Should the penetrant spread rapidly to this containment limit the penetration rate can be accurately quantified. For the hazard assessment of small droplets of toxic chemicals, such as cholinesterase inhibitors, limiting skin surface spread in vitro could lead to underestimation of percutaneous penetration and hence underestimation of systemic toxicity in vivo. The current study investigated the dependency of the percutaneous penetration of undiluted radiolabelled nerve agents (VX and soman (GD), 10 µl) on skin surface spread (pig and guinea pig) using Franz-type glass diffusion cells with an area available for diffusion of either 2.54 cm(2) or 14.87 cm(2). Both VX and GD spread to the edge of the 2.54 cm(2) cells, but, not the 14.87 cm(2) cells over the study duration. Amounts of VX and GD penetrating pig and guinea pig skin in the 2.54 cm(2) cells were less than in the 14.87 cm(2) cells (except for GD under unoccluded conditions); however, penetration rates expressed per unit area were similar. Artificial limitation of skin surface spread in vitro does not impact percutaneous penetration in vitro as long as penetration is expressed in terms of mass per unit area.


Assuntos
Agentes Neurotóxicos/farmacocinética , Compostos Organotiofosforados/farmacocinética , Soman/farmacocinética , Animais , Difusão , Cobaias , Técnicas In Vitro , Absorção Cutânea , Suínos
17.
ISME J ; 9(7): 1508-22, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25575311

RESUMO

Diverse microbial consortia profoundly influence animal biology, necessitating an understanding of microbiome variation in studies of animal adaptation. Yet, little is known about such variability among fish, in spite of their importance in aquatic ecosystems. The Trinidadian guppy, Poecilia reticulata, is an intriguing candidate to test microbiome-related hypotheses on the drivers and consequences of animal adaptation, given the recent parallel origins of a similar ecotype across streams. To assess the relationships between the microbiome and host adaptation, we used 16S rRNA amplicon sequencing to characterize gut bacteria of two guppy ecotypes with known divergence in diet, life history, physiology and morphology collected from low-predation (LP) and high-predation (HP) habitats in four Trinidadian streams. Guts were populated by several recurring, core bacteria that are related to other fish associates and rarely detected in the environment. Although gut communities of lab-reared guppies differed from those in the wild, microbiome divergence between ecotypes from the same stream was evident under identical rearing conditions, suggesting host genetic divergence can affect associations with gut bacteria. In the field, gut communities varied over time, across streams and between ecotypes in a stream-specific manner. This latter finding, along with PICRUSt predictions of metagenome function, argues against strong parallelism of the gut microbiome in association with LP ecotype evolution. Thus, bacteria cannot be invoked in facilitating the heightened reliance of LP guppies on lower-quality diets. We argue that the macroevolutionary microbiome convergence seen across animals with similar diets may be a signature of secondary microbial shifts arising some time after host-driven adaptation.


Assuntos
Evolução Biológica , Microbioma Gastrointestinal/genética , Poecilia/genética , Poecilia/microbiologia , Adaptação Fisiológica/genética , Distribuição Animal , Animais , Dieta , Ecossistema , Ecótipo , RNA Ribossômico 16S/genética , Trinidad e Tobago
18.
Proc Math Phys Eng Sci ; 471(2176): 20140891, 2015 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-27547080

RESUMO

To support the effort to eliminate the Syrian Arab Republic chemical weapons stockpile safely, there was a requirement to provide scientific advice based on experimentally derived information on both toxicity and medical countermeasures (MedCM) in the event of exposure to VM, VX or VM-VX mixtures. Complementary in vitro and in vivo studies were undertaken to inform that advice. The penetration rate of neat VM was not significantly different from that of neat VX, through either guinea pig or pig skin in vitro. The presence of VX did not affect the penetration rate of VM in mixtures of various proportions. A lethal dose of VM was approximately twice that of VX in guinea pigs poisoned via the percutaneous route. There was no interaction in mixed agent solutions which altered the in vivo toxicity of the agents. Percutaneous poisoning by VM responded to treatment with standard MedCM, although complete protection was not achieved.

19.
Oecologia ; 177(1): 245-57, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25430044

RESUMO

A trophic niche shift can occur as an adaptive response to environmental change such as altered resource quality, abundance or composition. Alterations in digestive traits such as gut morphology and physiology may enable these niche shifts and affect the persistence of populations and species. Relatively few studies, however, have assessed how niche shifts influence suites of digestive traits through phenotypic plasticity and evolutionary mechanisms, and how these trait changes can subsequently alter the nutrition, fitness and life history of organisms. We investigated how population divergence and plasticity alter the gut physiology of wild Trinidadian guppies (Poecilia reticulata), assessing whether variation in digestive traits correspond with enhanced nutrient assimilation under a pronounced dietary shift. We examined gut enzyme activity, and gut size and mass of wild guppies from both high-predation (HP) and low-predation (LP) habitats when reared in the laboratory and fed on high- or low-quality diets designed to reflect their dietary differences previously found in nature. After 10 weeks on the experimental diets, HP guppies maintained shorter and lighter guts than LP guppies on either diet. Guppies also differed in their digestive enzymatic profiles, more often reflecting nutrient balancing so that increased enzyme expression tended to correspond with more deficient nutrients in the diet. LP guppies had increased somatic phosphorus at the end of the experiment, possibly related to the higher alkaline phosphatase activity in their guts. Our results suggest that differences in gut physiology exist among populations of Trinidadian guppies that may reflect local adaptation to their disparate environments.


Assuntos
Adaptação Fisiológica , Dieta , Digestão , Ecossistema , Estado Nutricional , Poecilia/fisiologia , Comportamento Predatório , Adaptação Fisiológica/genética , Fosfatase Alcalina/metabolismo , Fenômenos Fisiológicos da Nutrição Animal , Animais , Evolução Biológica , Composição Corporal , Digestão/genética , Trato Gastrointestinal/anatomia & histologia , Trato Gastrointestinal/enzimologia , Fenótipo , Trinidad e Tobago
20.
J Appl Toxicol ; 35(5): 543-50, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-25219755

RESUMO

The risk of penetrating, traumatic injury occurring in a chemically contaminated environment cannot be discounted. Should a traumatic injury be contaminated with a chemical warfare (CW) agent, it is likely that standard haemostatic treatment options would be complicated by the need to decontaminate the wound milieu. Thus, there is a need to develop haemostatic products that can simultaneously arrest haemorrhage and decontaminate CW agents. The purpose of this study was to evaluate a number of candidate haemostats for efficacy as skin decontaminants against three CW agents (soman, VX and sulphur mustard) using an in vitro diffusion cell containing undamaged pig skin. One haemostatic product (WoundStat™) was shown to be as effective as the standard military decontaminants Fuller's earth and M291 for the decontamination of all three CW agents. The most effective haemostatic agents were powder-based and use fluid absorption as a mechanism of action to sequester CW agent (akin to the decontaminant Fuller's earth). The envisaged use of haemostatic decontaminants would be to decontaminate from within wounds and from damaged skin. Therefore, WoundStat™ should be subject to further evaluation using an in vitro model of damaged skin.


Assuntos
Substâncias para a Guerra Química/toxicidade , Descontaminação/métodos , Hemostáticos/farmacocinética , Ferimentos e Lesões/tratamento farmacológico , Compostos de Alumínio/farmacocinética , Animais , Compostos de Magnésio/farmacocinética , Gás de Mostarda/toxicidade , Compostos Organotiofosforados/toxicidade , Silicatos/farmacocinética , Pele/efeitos dos fármacos , Absorção Cutânea/efeitos dos fármacos , Soman/toxicidade , Suínos , Ferimentos e Lesões/induzido quimicamente , Ferimentos e Lesões/patologia
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