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1.
BMJ Mil Health ; 169(5): 413-418, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34663678

RESUMO

INTRODUCTION: Military veterans are at heightened risk of problem gambling. Little is known about the costs of problem gambling and related harm among United Kingdom (UK) Armed Forces (AF) veterans. We investigated the social and economic costs of gambling among a large sample of veterans through differences in healthcare and social service resource use compared with age-matched and gender-matched non-veterans from the UK AF Veterans' Health and Gambling Study. METHODS: An online survey measured sociodemographic characteristics, gambling experience and problem severity, mental health and healthcare resource utilisation. Healthcare provider, personal social service and societal costs were estimated as total adjusted mean costs and utility, with cost-consequence analysis of a single timepoint. RESULTS: Veterans in our sample had higher healthcare, social service and societal costs and lower utility. Veterans had greater contacts with the criminal justice system, received more social service benefits, had more lost work hours and greater accrued debt. A cost difference of £590 (95% CI -£1016 to -£163) was evident between veterans with scores indicating problem gambling and those reporting no problems. Costs varied by problem gambling status. CONCLUSIONS: Our sample of UK AF veterans has higher healthcare, social service and societal costs than non-veterans. Veterans experiencing problem gambling are more costly but have no reduction in quality of life.


Assuntos
Jogo de Azar , Militares , Veteranos , Humanos , Veteranos/psicologia , Jogo de Azar/epidemiologia , Jogo de Azar/psicologia , Qualidade de Vida , Reino Unido/epidemiologia
2.
Sci Adv ; 5(4): eaav9044, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30972369

RESUMO

Hypergolic materials, capable of spontaneous ignition upon contact with an external oxidizer, are of critical importance as fuels and propellants in aerospace applications (e.g., rockets and spacecraft). Currently used hypergolic fuels are highly energetic, toxic, and carcinogenic hydrazine derivatives, inspiring the search for cleaner and safer hypergols. Here, we demonstrate the first strategy to design hypergolic behavior within a metal-organic framework (MOF) platform, by using simple "trigger" functionalities to unlock the latent and generally not recognized energetic properties of zeolitic imidazolate frameworks, a popular class of MOFs. The herein presented six hypergolic MOFs, based on zinc, cobalt, and cadmium, illustrate a uniquely modular platform to develop hypergols free of highly energetic or carcinogenic components, in which varying the metal and linker components enables the modulation of ignition and combustion properties, resulting in excellent hypergolic response evident by ultrashort ignition delays as low as 2 ms.

3.
Psychol Med ; 45(8): 1591-600, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25697732

RESUMO

BACKGROUND: Borderline personality disorder (BPD) and bipolar disorder (BD) have overlapping clinical presentations and symptoms - sources of persistent clinical confusion. Game-theory can characterize how social function might be sub-optimal in the two disorders and move the field beyond the anecdotal description of clinical history. Here, we tested the hypothesis that BPD and BD can be distinguished on the basis of diminished reciprocal altruism in iterated Prisoner's Dilemma (PD) games. METHOD: Twenty females with BPD, 20 females with euthymic BD and 20 healthy (non-clinical) females, matched for age and cognitive ability, were assessed for Axis-I and personality disorders, and completed psychometric measures of state affect, impulsivity and hostility. Participants completed two iterated PD games and a test of gaze-cueing. RESULTS: In the PD games, BPD participants failed to show statistically stable preferences to cooperate with social partners (playing tit-for-tat) and made significantly fewer cooperative responses compared to BD or controls (ANOVA main effect p = 0.03, post-hoc Tukey p < 0.05 for both comparisons). BPD participants were also less likely to sustain cooperation following experiences involving mutual cooperation than the other groups. Neither BPD nor BD participants demonstrated impairments in shifting visual attention on the basis of other peoples' gaze. CONCLUSIONS: These data indicate that BPD is (selectively) associated with difficulties in establishing, and then maintaining, reciprocal cooperation, involving altruism. These difficulties are not seen in euthymic BD. Our data support the differentiation of BPD from BD and offer fresh insights into the social difficulties experienced by individuals with diagnoses of BPD.


Assuntos
Transtorno Bipolar/psicologia , Transtorno da Personalidade Borderline/psicologia , Comportamento Cooperativo , Transtornos do Humor/psicologia , Adolescente , Adulto , Afeto , Análise de Variância , Transtorno Bipolar/diagnóstico , Transtorno da Personalidade Borderline/diagnóstico , Feminino , Hostilidade , Humanos , Comportamento Impulsivo , Pessoa de Meia-Idade , Transtornos do Humor/diagnóstico , Dilema do Prisioneiro , Resolução de Problemas , Psicometria , Adulto Jovem
4.
Chem Commun (Camb) ; 51(20): 4294-7, 2015 Mar 11.
Artigo em Inglês | MEDLINE | ID: mdl-25673089

RESUMO

Hydrogen bond donating cosolvents have been shown to significantly reduce the solubility of acetaminophen (AAP) in ionic liquids containing the acetate anion. Reduced solubility arises from competition for solvation by the acetate anion and can be used for the design of advanced separation techniques, illustrated by the crystallization of AAP.


Assuntos
Acetaminofen/química , Líquidos Iônicos/química , Aminofenóis/química , Cristalização , Ligação de Hidrogênio , Solubilidade
5.
Chem Commun (Camb) ; 50(66): 9228-50, 2014 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-24830849

RESUMO

As highlighted by the recent ChemComm web themed issue on ionic liquids, this field continues to develop beyond the concept of interesting new solvents for application in the greening of the chemical industry. Here some current research trends in the field will be discussed which show that ionic liquids research is still aimed squarely at solving major societal issues by taking advantage of new fundamental understanding of the nature of these salts in their low temperature liquid state. This article discusses current research trends in applications of ionic liquids to energy, materials, and medicines to provide some insight into the directions, motivations, challenges, and successes being achieved with ionic liquids today.


Assuntos
Líquidos Iônicos , Medicina
6.
J Mater Chem B ; 2(25): 3924-3936, 2014 Jul 07.
Artigo em Inglês | MEDLINE | ID: mdl-32261644

RESUMO

Chitin-calcium alginate composite fibers were prepared from a solution of high molecular weight chitin extracted from shrimp shells and alginic acid in the ionic liquid 1-ethyl-3-methylimidazolium acetate by dry-jet wet spinning into an aqueous bath saturated with CaCO3. The fibers exhibited a significant proportion of the individual properties of both calcium alginate and chitin. Ultimate stress values were close to values obtained for calcium alginate fibers, and the absorption capacities measured were consistent with those reported for current wound care dressings. Wound healing studies (rat model, histological evaluation) indicated that chitin-calcium alginate covered wound sites underwent normal wound healing with re-epithelialization and that coverage of the dermal fibrosis with hyperplastic epidermis was consistently complete after only 7 days of treatment. Using a single patch per wound per animal during the entire study, all rat wounds achieved 95-99% closure by day 10 with complete wound closure by day 14.

7.
Acta Psychiatr Scand ; 128(3): 149-62, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23617548

RESUMO

OBJECTIVE: An association between bipolar disorder and cognitive impairment has repeatedly been described, even for euthymic patients. Findings are inconsistent both across primary studies and previous meta-analyses. This study reanalysed 31 primary data sets as a single large sample (N = 2876) to provide a more definitive view. METHOD: Individual patient and control data were obtained from original authors for 11 measures from four common neuropsychological tests: California or Rey Verbal Learning Task (VLT), Trail Making Test (TMT), Digit Span and/or Wisconsin Card Sorting Task. RESULTS: Impairments were found for all 11 test-measures in the bipolar group after controlling for age, IQ and gender (Ps ≤ 0.001, E.S. = 0.26-0.63). Residual mood symptoms confound this result but cannot account for the effect sizes found. Impairments also seem unrelated to drug treatment. Some test-measures were weakly correlated with illness severity measures suggesting that some impairments may track illness progression. CONCLUSION: This reanalysis supports VLT, Digit Span and TMT as robust measures of cognitive impairments in bipolar disorder patients. The heterogeneity of some test results explains previous differences in meta-analyses. Better controlling for confounds suggests deficits may be smaller than previously reported but should be tracked longitudinally across illness progression and treatment.


Assuntos
Sintomas Afetivos , Transtorno Bipolar , Transtornos Cognitivos , Competência Mental , Testes Neuropsicológicos , Psicotrópicos/efeitos adversos , Adulto , Afeto , Sintomas Afetivos/psicologia , Idade de Início , Transtorno Bipolar/complicações , Transtorno Bipolar/diagnóstico , Transtorno Bipolar/tratamento farmacológico , Transtorno Bipolar/epidemiologia , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/tratamento farmacológico , Transtornos Cognitivos/epidemiologia , Transtornos Cognitivos/etiologia , Fatores de Confusão Epidemiológicos , Feminino , Humanos , Masculino , Processos Mentais/efeitos dos fármacos , Pessoa de Meia-Idade , Escalas de Graduação Psiquiátrica , Psicotrópicos/administração & dosagem , Fatores de Risco
8.
Transl Psychiatry ; 3: e235, 2013 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-23443361

RESUMO

Electronic gaming machines (EGMs) offer significant revenue streams for mercantile gambling. However, limited clinical and experimental evidence suggests that EGMs are associated with heightened risks of clinically problematic patterns of play. Little is known about the neural structures that might mediate the transition from exploratory EGM play to the 'addictive' play seen in problem gamblers; neither is it known how personality traits associated with gambling activity (and gambling problems) influence reinforcement processing while playing EGMs. Using functional magnetic resonance imaging in healthy participants, we show that a single episode of slot-machine play is subsequently associated with reduced amplitudes of blood-oxygenation level-dependent signals within reinforcement-related structures, such as the ventral striatum and caudate nucleus, following winning game outcomes; but increased amplitudes of anticipatory signals within the ventral striatum and amygdala while watching the game reels spin. Trait impulsivity enhanced positive signals within the ventral striatum and amygdala following the delivery of winning outcomes but diminished positive signals following the experience of almost-winning ('near-misses'). These results indicate that a single episode of slot-machine play engages the well-characterised reinforcement-learning mechanisms mediated by ascending dopamine mesolimbic and mesostriatal pathways, to shift reward value of EGMs away from game outcomes towards anticipatory states. Impulsivity, itself linked to problem gambling and heightened vulnerability to other addictive disorders, is associated with divergent coding of winning outcomes and almost-winning experiences within the ventral striatum and amygdala, potentially enhancing the reward value of successful slot-machine game outcomes but, at the same time,modulating the aversive motivational consequences of near-miss outcomes.


Assuntos
Tonsila do Cerebelo/fisiologia , Antecipação Psicológica/fisiologia , Gânglios da Base/fisiologia , Jogo de Azar/psicologia , Comportamento Impulsivo/fisiopatologia , Reforço Psicológico , Adulto , Mapeamento Encefálico/métodos , Dopamina/metabolismo , Feminino , Humanos , Comportamento Impulsivo/psicologia , Imageamento por Ressonância Magnética/métodos , Masculino , Recompensa
9.
Transl Psychiatry ; 3: e213, 2013 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-23321810

RESUMO

Electronic gaming machines (EGMs) offer significant revenue streams for mercantile gambling. However, limited clinical and experimental evidence suggests that EGMs are associated with heightened risks of clinically problematic patterns of play. Little is known about the neural structures that might mediate the transition from exploratory EGM play to the 'addictive' play seen in problem gamblers; neither is it known how personality traits associated with gambling activity (and gambling problems) influence reinforcement processing while playing EGMs. Using functional magnetic resonance imaging in healthy participants, we show that a single episode of slot-machine play is subsequently associated with reduced amplitudes of blood-oxygenation-level-dependent signals within reinforcement-related structures, such as the ventral striatum and caudate nucleus, following winning game outcomes; but increased amplitudes of anticipatory signals within the ventral striatum and amygdala while watching the game reels spin. Trait impulsivity enhanced positive signals within the ventral striatum and amygdala following the delivery of winning outcomes but diminished positive signals following the experience of almost-winning ('near-misses'). These results indicate that a single episode of slot-machine play engages the well-characterised reinforcement-learning mechanisms mediated by ascending dopamine mesolimbic and mesostriatal pathways, to shift reward value of EGMs away from game outcomes towards anticipatory states. Impulsivity, itself linked to problem gambling and heightened vulnerability to other addictive disorders, is associated with divergent coding of winning outcomes and almost-winning experiences within the ventral striatum and amygdala, potentially enhancing the reward value of successful slot-machine game outcomes but, at the same time, modulating the aversive motivational consequences of near-miss outcomes.


Assuntos
Tonsila do Cerebelo/fisiologia , Antecipação Psicológica/fisiologia , Gânglios da Base/fisiologia , Dopamina/metabolismo , Jogo de Azar/psicologia , Reforço Psicológico , Adulto , Tonsila do Cerebelo/química , Gânglios da Base/química , Mapeamento Encefálico , Feminino , Jogo de Azar/sangue , Humanos , Comportamento Impulsivo/fisiopatologia , Comportamento Impulsivo/psicologia , Imageamento por Ressonância Magnética , Masculino , Recompensa
10.
Exp Brain Res ; 225(2): 227-35, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23239199

RESUMO

We sought to explore the interaction of the impulsivity trait with response uncertainty. To this end, we used a reaching task (Pellizzer and Hedges in Exp Brain Res 150:276-289, 2003) where a motor response direction was cued at different levels of uncertainty (1 cue, i.e., no uncertainty, 2 cues or 3 cues). Data from 95 healthy adults (54 F, 41 M) were analysed. Impulsivity was measured using the Barratt Impulsiveness Scale version 11 (BIS-11). Behavioral variables recorded were reaction time (RT), errors of commission (referred to as 'early errors') and errors of precision. Data analysis employed generalised linear mixed models and generalised additive mixed models. For the early errors, there was an interaction of impulsivity with uncertainty and gender, with increased errors for high impulsivity in the one-cue condition for women and the three-cue condition for men. There was no effect of impulsivity on precision errors or RT. However, the analysis of the effect of RT and impulsivity on precision errors showed a different pattern for high versus low impulsives in the high uncertainty (3 cue) condition. In addition, there was a significant early error speed-accuracy trade-off for women, primarily in low uncertainty and a 'reverse' speed-accuracy trade-off for men in high uncertainty. These results extend those of past studies of impulsivity which help define it as a behavioural trait that modulates speed versus accuracy response styles depending on environmental constraints and highlight once more the importance of gender in the interplay of personality and behaviour.


Assuntos
Comportamento Impulsivo/fisiopatologia , Desempenho Psicomotor/fisiologia , Incerteza , Adolescente , Adulto , Atenção/fisiologia , Sinais (Psicologia) , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Tempo de Reação/fisiologia , Fatores Sexuais
12.
Phys Chem Chem Phys ; 13(26): 12138-45, 2011 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-21643584

RESUMO

Pair association in Ionic Liquids is an important quantity that affects many of their physical and chemical properties. However, the association constant is a complex function of the component ions as well as of the solvent environment, and no single theory can compute or predict it with quantitative accuracy. In this work we analyze infinite-dilution association data from a number of recent conductance measurements, and develop a linear model correlating the association constant with two relevant interaction energies, i.e., (1) the dielectrically screened Coulomb attraction and hydrogen bonding between ion-pairs, and (2) the ion solvation energy, which in turn takes into account solvent-specific interactions like hydrogen-bond acidity/basicity and hydrophobic/hydrophilic interactions. The results reveal the unique nature of water as a solvent in that it affects ionic association in ways qualitatively different from other common solvents.

13.
J Psychopharmacol ; 23(7): 831-40, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18583436

RESUMO

Omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation may be beneficial in the treatment of several psychiatric disorders, including depression. A small number of studies have suggested that there may also be cognitive and mood effects in healthy samples. The purpose of the present study was to investigate the effects of n-3 PUFA on depression-relevant cognitive functioning in healthy individuals. Fifty-four healthy university students were randomized to receive either n-3 PUFA supplements or placebo for 4 weeks in a double-blind design. The test battery included measures of cognitive reactivity, attention, response inhibition, facial emotion recognition, memory and risky decision-making. Results showed few effects of n-3 PUFAs on cognition and mood states. The n-3 PUFA group made fewer risk-averse decisions than the placebo group. This difference appeared only in non-normative trials of the decision-making test, and was not accompanied by increased impulsiveness. N-3 PUFAs improved scores on the control/perfectionism scale of the cognitive reactivity measure. No effects were found on the other cognitive tasks and no consistent effects on mood were observed. The present findings indicate that n-3 PUFA supplementation may have a selective effect on risky decision making in healthy volunteers, which is unrelated to impulsiveness.


Assuntos
Cognição/efeitos dos fármacos , Ácidos Graxos Ômega-3/farmacologia , Afeto/efeitos dos fármacos , Tomada de Decisões/efeitos dos fármacos , Depressão/dietoterapia , Suplementos Nutricionais , Ácidos Graxos Ômega-3/sangue , Ácidos Graxos Ômega-3/uso terapêutico , Feminino , Humanos , Masculino , Cooperação do Paciente , Desempenho Psicomotor/efeitos dos fármacos , Adulto Jovem
14.
Psychopharmacology (Berl) ; 182(1): 160-9, 2005 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-16032411

RESUMO

RATIONALE: Many studies have reported the long-term adverse effects of alcohol on executive cognitive function in chronic alcohol abusers, yet little research has investigated the acute effects of alcohol in social drinkers. Studies on acute effects report alcohol-induced deficits on tasks that require executive cognitive processes, with alcohol acting to increase preservative errors and reduce planning. AIM: The present investigation examines the acute effects of a moderate dose of alcohol on a decision-making task that involves participants making a forced choice between two simultaneously presented binary-outcome gambles. METHODS: Alcohol (0.6 g/kg) or placebo was administered to 32 social drinkers. Participants completed the task, making a total of 80 decisions about gambles that varied in the magnitude of expected gains, losses and the probability with which these outcomes were delivered. Participants also chose between gambles probing identified non-normative biases in human decision making, namely, risk aversion for choosing between gains and risk seeking for choosing between losses. RESULTS: All participants picked the experimental gamble more frequently when the probability of winning was high vs low, when the gains were large vs small and when the losses were small vs large; the alcohol group had an impaired ability to factor in the magnitude of gains and the likelihood of winning when the losses were large. Deliberation time did not differ between the groups. CONCLUSION: These data suggest that alcohol given acutely impairs risky decision making. In particular, alcohol impairs one's ability to alter responding in light of changing prospective rewards in order to make favourable decisions.


Assuntos
Intoxicação Alcoólica/psicologia , Tomada de Decisões/efeitos dos fármacos , Etanol/efeitos adversos , Adulto , Afeto/efeitos dos fármacos , Comportamento de Escolha/efeitos dos fármacos , Aprendizagem por Discriminação/efeitos dos fármacos , Método Duplo-Cego , Feminino , Jogo de Azar/psicologia , Humanos , Masculino , Memória de Curto Prazo/efeitos dos fármacos , Testes Neuropsicológicos , Medição da Dor , Reconhecimento Visual de Modelos/efeitos dos fármacos , Inventário de Personalidade , Tempo de Reação/efeitos dos fármacos , Leitura , Semântica , Enquadramento Psicológico , Percepção da Fala/efeitos dos fármacos , Aprendizagem Verbal/efeitos dos fármacos
15.
Psychopharmacology (Berl) ; 179(4): 761-8, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15696331

RESUMO

RATIONALE: We have previously shown that a 60-g mixture of branched chain amino acids (BCAAs) lowers the plasma availability of the catecholamine precursors tyrosine (TYR) and phenylalanine (PHE) and produces biochemical and neuropsychological changes consistent with impaired dopamine neurotransmission. However, the BCAA mixture also lowers the ratio of tryptophan (TRP) to BCAA which could impair brain serotonin function. OBJECTIVES: To determine the biochemical and neuropsychological effects of a BCAA mixture supplemented with TRP. METHODS: We studied 32 healthy volunteers who were randomly and blindly allocated to either a single administration of amino acid mixture (60 g BCAA and 2 g TRP) or placebo. We carried out venous sampling to measure plasma levels of amino acids and performed selected cognitive tasks sensitive to monoamine manipulation 5 h after mixture ingestion. RESULTS: Relative to placebo, the BCAA/TRP mixture substantially lowered the ratio of TYR+PHE:BCAA and increased plasma prolactin. The ratio of TRP:BCAA was also lowered but to a lesser extent. The BCAA/TRP mixture produced significant changes in a task of decision-making where volunteers showed reduced discrimination between gambles with large and small losses. CONCLUSIONS: A 62 g BCAA/TRP mixture decreases the availability of TYR and PHE for brain catecholamine synthesis and increases plasma prolactin consistent with lowered brain dopamine function. Addition of 2 g TRP to the 60 g BCAA mixture does not prevent a reduction of the ratio TRP:BCAA relative to placebo. The effects of the BCAA/TRP mixture on decision-making suggest a general action of dopamine pathways on the processing of emotional information in risky choice, including punishment-related cues, consistent with suggestions that dopamine mechanisms mediate behavioural responses to aversive as well as appetitive stimuli in instrumental conditioning.


Assuntos
Aminoácidos de Cadeia Ramificada/farmacologia , Tomada de Decisões/efeitos dos fármacos , Neurotransmissores/fisiologia , Triptofano/farmacologia , Adulto , Afeto/efeitos dos fármacos , Idoso , Química Encefálica/efeitos dos fármacos , Sinais (Psicologia) , Método Duplo-Cego , Feminino , Jogo de Azar/psicologia , Humanos , Masculino , Memória/efeitos dos fármacos , Memória de Curto Prazo/efeitos dos fármacos , Pessoa de Meia-Idade , Testes Neuropsicológicos , Reconhecimento Visual de Modelos/efeitos dos fármacos , Fenilalanina/metabolismo , Prolactina/sangue , Desempenho Psicomotor/efeitos dos fármacos , Percepção Espacial/efeitos dos fármacos
16.
Neuroimage ; 21(4): 1407-15, 2004 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-15050566

RESUMO

Actions are said to be 'willed' if we consciously pay attention to their selection. It has been suggested that they are associated with activations in the dorsal prefrontal cortex (area 46). However, because previous experiments typically used a 'free selection' paradigm to examine this hypothesis, it is unclear whether the results reflected the attention to the selection of action or the freedom of choice allowed by the tasks. In this experiment, we minimized the difference of working memory demand across task conditions by using novel stimuli in each trial. We found that activation in the dorsal prefrontal cortex on a free selection task was not significantly different from that induced by another task that required attention to the selection of action, although the responses were externally specified. This suggests that the dorsal prefrontal cortex is in fact associated with attention to the selection of action, but does not play a unique role in the generation of internally initiated actions. However, the presupplementary motor area (pre-SMA) may subserve this function as activity in this region was found to be tightly associated with the free selection of responses.


Assuntos
Atenção/fisiologia , Comportamento de Escolha/fisiologia , Aprendizagem por Discriminação/fisiologia , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Motivação , Orientação/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Córtex Pré-Frontal/fisiologia , Desempenho Psicomotor/fisiologia , Adulto , Encéfalo/fisiologia , Mapeamento Encefálico , Dominância Cerebral/fisiologia , Feminino , Humanos , Controle Interno-Externo , Masculino , Memória de Curto Prazo/fisiologia , Tempo de Reação/fisiologia , Jogos de Vídeo
17.
Psychopharmacology (Berl) ; 172(2): 157-64, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14716472

RESUMO

RATIONALE: Converging evidence from studies with neurological patients and brain imaging studies with healthy volunteers suggests that the capacity to make choices between actions associated with probabilistic rewards and punishments depends upon a network of cortico-limbic systems including the orbitofrontal cortex, cingulate cortex, amygdala and striatum. The involvement of such structures highlights the emotional aspects of decision-making and suggests that decision-making may be sensitive to manipulations of the catecholamine systems that innervate these structures. In this study, we investigated the possible role of noradrenaline (NA). OBJECTIVE: We examined the effects of a single oral 80 mg dose of the beta-adrenoceptor blocker, propranolol, on the decision-making of healthy volunteers in a double-blind, placebo-controlled, between-subjects design. METHODS: Seventeen volunteers ingested a placebo while 15 volunteers ingested propranolol. Visual analogue scales, and self-reported positive and negative ratings, were used to assess subjective changes and mood. Vital signs were also monitored. Seventy-five minutes after treatment, volunteers were asked to make a series of choices between two simultaneously presented gambles, differing in the magnitude of possible gains (i.e. reward), the magnitude of possible losses (i.e. punishment), and the probabilities with which these outcomes were delivered. Volunteers also chose between gambles probing identified non-cognitive biases in human decision-making, namely, risk-aversion when choosing between gains and risk-seeking when choosing between losses. RESULTS: Propranolol treatment did not result in gross changes in subjective state or mood in comparison to placebo, but did slow heart rate significantly. Propranolol produced a selective change in volunteers' decision-making; namely, it significantly reduced the discrimination between large and small possible losses when the probability of winning was relatively low and the probability of losing was high. CONCLUSIONS: These results suggest that NA modulates the processing of punishment signals when choosing between probabilistic rewards and punishments under conditions of increased arousal.


Assuntos
Antagonistas Adrenérgicos beta/farmacologia , Tomada de Decisões/efeitos dos fármacos , Receptores Adrenérgicos beta/fisiologia , Adolescente , Adulto , Análise de Variância , Distribuição de Qui-Quadrado , Tomada de Decisões/fisiologia , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
18.
Psychopharmacology (Berl) ; 167(4): 411-7, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12677354

RESUMO

RATIONALE: Serotonergic processes have been implicated in the modulation of fear conditioning in humans, postulated to occur at the level of the amygdala. The processing of other fear-relevant cues, such as facial expressions, has also been associated with amygdala function, but an effect of serotonin depletion on these processes has not been assessed. OBJECTIVE: The present study investigated the effects of reducing serotonin function, using acute tryptophan depletion, on the recognition of basic facial expressions of emotions in healthy male and female volunteers. METHODS: A double-blind between-groups design was used, with volunteers being randomly allocated to receive an amino acid drink specifically lacking tryptophan or a control mixture containing a balanced mixture of these amino acids. Participants were given a facial expression recognition task 5 h after drink administration. This task featured examples of six basic emotions (fear, anger, disgust, surprise, sadness and happiness) that had been morphed between each full emotion and neutral in 10% steps. As a control, volunteers were given a famous face classification task matched in terms of response selection and difficulty level. RESULTS: Tryptophan depletion significantly impaired the recognition of fearful facial expressions in female, but not male, volunteers. This was specific since recognition of other basic emotions was comparable in the two groups. There was also no effect of tryptophan depletion on the classification of famous faces or on subjective state ratings of mood or anxiety. CONCLUSIONS: These results confirm a role for serotonin in the processing of fear related cues, and in line with previous findings also suggest greater effects of tryptophan depletion in female volunteers. Although acute tryptophan depletion does not typically affect mood in healthy subjects, the present results suggest that subtle changes in the processing of emotional material may occur with this manipulation of serotonin function.


Assuntos
Expressão Facial , Medo , Reconhecimento Visual de Modelos/fisiologia , Percepção Social , Triptofano/fisiologia , Adulto , Método Duplo-Cego , Feminino , Humanos , Masculino , Serotonina/metabolismo , Fatores Sexuais , Análise e Desempenho de Tarefas , Triptofano/sangue , Triptofano/deficiência
19.
Psychol Med ; 32(8): 1395-405, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12455938

RESUMO

BACKGROUND: Repeated, self-damaging behaviour occurring in the context of borderline personality disorder (BPD) may reflect impairments in decision-making and planning cognition. However, there has been no systematic neuropsychological examination of these particular cognitive functions in patients diagnosed with BPD. Such investigations may improve our understanding of the possible role of brain dysfunction in BPD and improve the characterization of the psychological difficulties associated with this disorder. METHOD: Forty-two psychiatric patients with a diagnosis of DSM-III-R BPD (41 of whom gave a history of self-harm), without a history of specified 'psychoses' or current major affective disorder, were clinically assessed before completing computerized tasks of decision-making and planning previously shown to be sensitive to frontal lobe dysfunction, and tests of spatial and pattern visual recognition memory previously shown to be sensitive to frontal lobe damage and temporal lobe damage respectively. The performance of the BPD patient group was compared with that of a non-clinical control group consisting of 42 subjects. RESULTS: The performance of the BPD patients on the decision-making task was characterized by a pattern of delayed and maladaptive choices when choosing between competing actions, and by impulsive, disinhibited responding when gambling on the outcome of their decisions. BPD patients also showed impairments on the planning task. There was no evidence of impaired visual recognition memory. Additional analyses suggested only limited effects of current medication and history of previous substance use disorder. CONCLUSIONS: These findings suggest that BPD is associated with complex impairments in dissociable cognitive processes mediated by circuitry encompassing the frontal lobes. These impairments may mediate some of the behavioural changes evident in BPD. Further work is needed to examine the specificity of these findings.


Assuntos
Transtorno da Personalidade Borderline/psicologia , Transtornos Cognitivos/psicologia , Comportamento Autodestrutivo/psicologia , Adolescente , Adulto , Transtorno da Personalidade Borderline/epidemiologia , Transtorno da Personalidade Borderline/fisiopatologia , Tomada de Decisões , Manual Diagnóstico e Estatístico de Transtornos Mentais , Feminino , Lobo Frontal/fisiopatologia , Humanos , Masculino , Memória , Pessoa de Meia-Idade , Testes Neuropsicológicos , Transtornos Relacionados ao Uso de Substâncias/psicologia
20.
Biochem Soc Trans ; 30(4): 758-62, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12196188

RESUMO

To achieve cellular iron deprivation by chelation, it is important to develop chelators with selective metal-binding properties. Selectivity for iron has long been the province of certain oxygen-donor chelators such as desferrioxamine, which target Fe(III) and exploit the strength of a relatively ionic Fe(III)-O interaction. We have been studying novel chelators that possess mechanisms to selectively chelate +2 biometals, particularly tachpyr [N,N',N"-tris(2-pyridylmethyl)-1,3,5-cis,cis-triaminocyclohexane] and derivatives from N,N',N"-trialkylation and pyridine ring alkylation. Metal-exchange and metal-binding competition reactions have been conducted at pH 7.4, 37 degrees C and time periods until no further change was observed (generally 24-48 h). Under anaerobic conditions, tachpyr is strongly selective for iron, binding 95+/-5% Fe(II) versus 5+/-5% Zn(II) in the forms [Fe(tachpyr)](2+) and [Zn(tachpyr)](2+) respectively. Under aerobic conditions, tachpyr complexes Fe(II) more effectively than Fe(III), forming iminopyridyl complexes [Fe(tachpyr-ox-n)](2+) (n=2, 4) by O(2)-induced and iron-mediated oxidative dehydrogenation. Complexes [Fe(tachpyr-ox-n)](2+) are also strongly bound forms of iron that are unaffected by an excess of Zn(II) (75 mol zinc:1 mol iron complex). The preference of tachpyr for iron over zinc under aerobic conditions appears to be hindered by oxidation of Fe(II) to Fe(III), such that the proportions bound are 44+/-10% Fe(II) versus 56+/-10% Zn(II), in the respective forms [Fe(tachpyr-ox-n)](2+) and [Zn(tachpyr)](2+). However, upon addition of the reducing agent Na(2)S(2)O(4) that converts Fe(III) to Fe(II), the binding proportions shift to 76+/-10% Fe(II) versus 24+/-10% Zn(II), demonstrating a clear preference of tachpyr for Fe(II) over Zn(II). Iron(II) is in the low-spin state in [Fe(tachpyr)](2+) and [Fe(tachpyr-ox-n)](2+) (n=2, 4), which is a likely cause of the observed selectivity. N-methylation of tachpyr [giving (N-methyl)(3)tachpyr] results in the loss of selectivity for Fe(II), which is attributed to the steric effect of the methyl groups and a resulting high-spin state of Fe(II) in [Fe(N-methyl)(3)tachpyr)](2+). The relationship of chelator selectivity to cytotoxicity in the tach family will be discussed.


Assuntos
Quelantes/química , Quelantes/toxicidade , Quelantes de Ferro/química , Quelantes de Ferro/toxicidade , Zinco/toxicidade , Aerobiose , Cicloexilaminas/química , Cicloexilaminas/toxicidade , Estrutura Molecular , Piridinas/química , Piridinas/toxicidade
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