RESUMO
Temper outbursts are a severe problem for people with Prader-Willi Syndrome (PWS). Previous reports indicate that vagus nerve stimulation (VNS) may reduce maladaptive behaviour in neurodevelopmental disorders, including PWS. We systematically investigated the effectiveness of transcutaneous VNS (t-VNS) in PWS. Using a non-blind single case repeat measures modified ABA design, with participants as their own controls, t-VNS was evaluated in five individuals with PWS [three males; age 22-41 (M = 26.8)]. After a baseline phase, participants received four-hours of t-VNS daily for 12 months, followed by one month of daily t-VNS for two-hours. The primary outcome measure was the mean number of behavioural outbursts per day. Secondary outcomes included findings from behavioural questionnaires and both qualitative and goal attainment interviews. Four of the five participants who completed the study exhibited a statistically significant reduction in number and severity of temper outbursts after approximately nine months of daily four-hour t-VNS. Subsequent two-hour daily t-VNS was associated with increased outbursts for all participants, two reaching significance. Questionnaire and interview data supported these findings, the latter indicating potential mechanisms of action. No serious safety issues were reported. t-VNS is an effective, novel and safe intervention for chronic temper outbursts in PWS. We propose these changes are mediated through vagal projections and their effects both centrally and on the functioning of the parasympathetic nervous system. These findings challenge our present biopsychosocial understanding of such behaviours suggesting that there is a single major mechanism that is modifiable using t-VNS. This intervention is potentially generalizable across other clinical groups. Future research should address the lack of a sham condition in this study along with the prevalence of high drop out rates, and the potential effects of different stimulation intensities, frequencies and pulse widths.
Assuntos
Síndrome de Prader-Willi/terapia , Estimulação do Nervo Vago/métodos , Adulto , Ira , Feminino , Humanos , Masculino , Autorrelato , Inquéritos e Questionários , Temperamento , Estimulação Elétrica Nervosa Transcutânea/métodos , Resultado do Tratamento , Nervo Vago/fisiologiaRESUMO
B vitamins are essential for optimal brain and body function, and are particularly important for cortical metabolic processes that have downstream effects on mitigating oxidative stress. Oxidative stress has been linked to poor psychological outcomes including psychological distress, which has wide-reaching implications for the community and the workplace. Given work-related stress has been associated with poor mental health outcomes, high-dose B vitamin supplementation may be effective in improving brain function and psychological outcomes via attenuation of oxidative stress. This randomized, double-blind, placebo-controlled study investigated psychological outcomes following 6-month supplementation of a high-B-vitamin multivitamin in a large sample of healthy adults (n = 108, aged 30-70 years), as well as changes in default mode network functional connectivity in a subset of the original sample (n = 28). Improvements in occupational stress, general health, perceived stress, depressive symptoms, and mood profiles were identified for both active and placebo groups over time (p < 0.05 corrected). Seed-based functional connectivity analysis centered on the posterior cingulate cortex (PCC) showed that connectivity between the PCC and the caudate increased for the active treatment group, but decreased for the placebo group (p < 0.05 corrected). These findings reveal a substantial intervention effect for both active and placebo treatments, which could in part be associated with a placebo effect in subjective measures. There was, however, a significant treatment effect in the objective measure of functional connectivity, suggesting that reduced psychological stress and high-B-vitamin multivitamin supplementation may lead to an increase in DMN and caudate functional connectivity, which might reflect a strengthening of neurocircuitry within areas associated with reward and emotion at rest. Future studies should consider a placebo run-in methodology to reduce the placebo effect on the subjective measures of stress.
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A diet rich in B-group vitamins is essential for optimal body and brain function, and insufficient amounts of such vitamins have been associated with higher levels of neural inflammation and oxidative stress, as marked by increased blood plasma homocysteine. Neural biomarkers of oxidative stress quantified through proton magnetic spectroscopy (1H-MRS) are not well understood, and the relationship between such neural and blood biomarkers is seldom studied. The current study addresses this gap by investigating the direct effect of 6-month high-dose B-group vitamin supplementation on neural and blood biomarkers of metabolism. Using a randomized, double-blind, placebo-controlled design, 32 healthy adults (20 female, 12 male) aged 30â»65 years underwent blood tests (vitamin B6, vitamin B12, folate, and homocysteine levels) and 1H-MRS of the posterior cingulate cortex (PCC) and dorsolateral prefrontal cortex (DLPFC) before and after supplementation. Results confirmed the supplement was effective in increasing vitamin B6 and vitamin B12 levels and reducing homocysteine, whereas there was no change in folate levels. There were significant relationships between vitamin B6 and N-acetylaspartate (NAA), choline, and creatine, as well as between vitamin B12 and creatine (ps < 0.05), whereas NAA in the PCC increased, albeit not significantly (p > 0.05). Together these data provide preliminary evidence for the efficacy of high-dose B-group supplementation in reducing oxidative stress and inflammation through increasing oxidative metabolism. It may also promote myelination, cellular metabolism, and energy storage.
Assuntos
Antioxidantes/farmacologia , Encéfalo/efeitos dos fármacos , Suplementos Nutricionais , Estresse Oxidativo/efeitos dos fármacos , Complexo Vitamínico B/farmacologia , Adulto , Idoso , Ácido Aspártico/análogos & derivados , Ácido Aspártico/metabolismo , Biomarcadores/metabolismo , Encéfalo/metabolismo , Cognição , Transtornos Cognitivos , Creatina/metabolismo , Método Duplo-Cego , Feminino , Homocisteína/metabolismo , Humanos , Inflamação/prevenção & controle , Masculino , Pessoa de Meia-Idade , Complexo Vitamínico B/sangue , Complexo Vitamínico B/metabolismoAssuntos
Euphausiacea , Óleos de Peixe , Animais , Bivalves , Cartilagem , Citocinas , Suplementos Nutricionais , Cães , Ácidos Graxos Ômega-3RESUMO
BACKGROUND: Workplace stress in Australia and other western countries has been steadily increasing over the past decade. It can be observed not only in terms of increased compensation claims but also costs due to absenteeism, loss of productivity at work and reduced psychological and physiological health and well-being. Given the cost and pervasive effects of stress in the modern workforce, time efficient and cost-effective interventions capable of reducing occupational stress (or strain) and burnout are urgently required for the improved well-being of stressed employees. One intervention gaining scientific traction is supplementation with nutritional interventions, particularly the B group vitamins. METHODS: This study was developed to examine the effects of B group vitamins on workplace stress and mood variables with a sample of full-time employed older adults who subjectively report feeling stressed. The study is a randomized, double-blind, placebo-controlled, parallel-groups clinical trial where 200 (N = 100/group) participants will be randomized to receive Blackmores® Executive B Stress Formula or placebo daily for a period of 6 months. Participants will be tested at baseline and 6 months post-randomization on workplace stress, cognitive, personality and mood measures, cardiovascular (brachial and aortic systolic and diastolic blood pressures as well as arterial stiffness), biochemical (assays to measure inflammation and safety) as well as genetic assessments (to assess stress processing) and neuroimaging measures (to investigate in vivo mechanisms of action of B vitamins). In addition to this pre- and post- supplementation testing, participants will also complete a battery of self-report questionnaires online to assess their stress and mood once a month for the duration of the study. The primary aim of the study is to investigate the effects of B vitamin supplementation on work related stress. The secondary aims are to explore the mechanisms underpinning any changes in mood or workplace stress due to the B vitamin intervention by examining relationships between cognitive, biological, neuroimaging and cardiovascular variables over 6 months. A subset of 40 participants (N = 20/group) will undergo neuroimaging at baseline and at 6 months using functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy (MRS) in order to further explore in vivo mechanisms of action of B vitamins. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Register (ANZCTR):ACTRN12613000294752.
Assuntos
Dieta , Doenças Profissionais/psicologia , Estresse Psicológico/tratamento farmacológico , Complexo Vitamínico B/administração & dosagem , Adulto , Afeto , Idoso , Austrália , Cognição , Análise Custo-Benefício , Suplementos Nutricionais/economia , Método Duplo-Cego , Feminino , Humanos , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Placebos , Estresse Psicológico/prevenção & controle , Inquéritos e Questionários , Resultado do TratamentoRESUMO
BACKGROUND: Migraine is a chronic disabling neurovascular condition that may in part be caused by endothelial and cerebrovascular disruption induced by hyperhomocysteinaemia. We have previously provided evidence indicating that reduction of homocysteine by vitamin supplementation can reduce the occurrence of migraine in women. The current study examined the genotypic effects of methylenetetrahydrofolate reductase (MTHFR) and methionine synthase reductase (MTRR) gene variants on the occurrence of migraine in response to vitamin supplementation. METHODS: This was a 6-month randomized, double-blinded placebo-controlled trial of daily vitamin B supplementation (B(6), B(9) and B(12)) on reduction of homocysteine and of the occurrence of migraine in 206 female patients diagnosed with migraine with aura. RESULTS: Vitamin supplementation significantly reduced homocysteine levels (P<0.001), severity of headache in migraine (P=0.017) and high migraine disability (P=0.022) in migraineurs compared with the placebo effect (P>0.1). When the vitamin-treated group was stratified by genotype, the C allele carriers of the MTHFR C677T variant showed a higher reduction in homocysteine levels (P<0.001), severity of pain in migraine (P=0.01) and percentage of high migraine disability (P=0.009) compared with those with the TT genotypes. Similarly, the A allele carriers of the MTRR A66G variants showed a higher level of reduction in homocysteine levels (P<0.001), severity of pain in migraine (P=0.002) and percentage of high migraine disability (P=0.006) compared with those with the GG genotypes. Genotypic analysis for both genes combined indicated that the treatment effect modification of the MTRR variant was independent of the MTHFR variant. CONCLUSION: This provided further evidence that vitamin supplementation is effective in reducing migraine and also that both MTHFR and MTRR gene variants are acting independently to influence treatment response in female migraineurs.
Assuntos
Suplementos Nutricionais , Ferredoxina-NADP Redutase/genética , Genótipo , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Enxaqueca com Aura/tratamento farmacológico , Vitaminas/administração & dosagem , Adolescente , Adulto , Alelos , Método Duplo-Cego , Feminino , Ácido Fólico/administração & dosagem , Humanos , Pessoa de Meia-Idade , Enxaqueca com Aura/enzimologia , Enxaqueca com Aura/genética , Efeito Placebo , Vitamina B 12/administração & dosagem , Vitamina B 6/administração & dosagem , Adulto JovemRESUMO
OBJECTIVES: To describe ways of coping in people with mild to moderate AD when faced with situations that are challenging to their memory. METHOD: Twenty-four participants (12 with mild and 12 with moderate AD) were presented with a set of seven tasks that were analogues of everyday situations that tax memory. The participants' responses were videotaped and analysed. RESULTS: Participants' coping responses were grouped into seven categories to best reflect the main strategies. Individuals used a significantly greater frequency of effortful problem solving (self-reliance and reliance on carers) (p < 0.01) than other ways of coping. Positive acknowledgement of memory difficulties was used significantly more than negative acknowledgement and defensive coping (concealment and avoidance) (p < 0.01). CONCLUSION: This study used novel methodology of observation of behavioural responses in analogues of everyday situations. The predominance of effortful problem-solving emphasizes the role of the person with AD as an active agent in the management of memory loss. An emphasis in previous literature on defensive coping and denial is counter-balanced by the finding that participants commonly coped by acknowledging their memory impairment.
Assuntos
Adaptação Psicológica , Doença de Alzheimer/psicologia , Memória , Idoso , Idoso de 80 Anos ou mais , Comportamento , Feminino , Humanos , Masculino , Programas Nacionais de Saúde , Observação , Resolução de Problemas , Testes Psicológicos , Reino Unido , Gravação de VideoteipeRESUMO
N-methyl-D-aspartate (NMDA) receptors play an important role in learning and memory. Targeting the glycine modulatory site of the NMDA receptor has been suggested as a therapeutic strategy to improve cognition, although findings have not been convincing. We used the Cognitive Drug Research computerised assessment system to examine the effects of high-dose glycine on a number of cognitive processes in healthy young subjects. The study was a randomised placebo controlled repeated measures design in which each subject received acute placebo or glycine (0.8 g/kg) orally, with treatment conditions separated by a 5-day washout period. No significant effects of glycine were found on measures of working memory, declarative memory, attention or perceptual processing. These findings, together with those of previous studies, cast doubt over the ability of acute high-dose glycine to improve cognitive function in healthy subjects and suggest that the optimum dose of glycine for improving cognition may vary between different populations, possibly due to differences in endogenous glycine levels and the functional status of NMDA receptors.
Assuntos
Cognição/efeitos dos fármacos , Glicinérgicos/farmacologia , Glicina/farmacologia , Memória/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Adulto , Atenção/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Glicina/administração & dosagem , Glicinérgicos/administração & dosagem , Humanos , Masculino , Desempenho Psicomotor/efeitos dos fármacos , Tempo de Reação/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/metabolismo , Percepção Visual/efeitos dos fármacosRESUMO
RATIONALE: The loudness dependence of the auditory evoked Potential (LDAEP) has been suggested to be a putative marker of central serotonin function, with reported abnormalities in clinical disorders presumed to reflect serotonin dysfunction. Despite considerable research, very little is known about the LDAEP's sensitivity to other neurotransmitter systems. OBJECTIVES: Given the role of N-methyl-D-aspartate (NMDA) receptors in modulating pyramidal cell activity in cortico-cortico and thalamo-cortical loops, we examined the effect of targeting the glycine modulatory site of the NMDA receptor with high-dose glycine on the LDAEP in healthy subjects. MATERIALS AND METHODS: The study was a double-blind, placebo-controlled repeated-measures design in which 14 healthy participants were tested under two acute treatment conditions, placebo and oral glycine (0.8 g/kg). Changes in the amplitude of the N1/P2 at varying intensities (60, 70, 80, 90, 100 dB) were examined at C(Z). RESULTS: Compared to placebo, high-dose glycine induced a weaker LDAEP (a pronounced decrease in the slope of the N1/P2 with increasing tone loudness; p < 0.02). CONCLUSION: While the exact mechanism responsible for the effects of glycine on the LDAEP are not known, the findings suggest an inhibitory effect in the cortex, possibly via activation of NMDA receptors on GABA interneurons or inhibitory glycine receptors. The findings add to the growing literature exhibiting modulation of the LDAEP by multiple neurochemical systems in addition to the serotonergic system.
Assuntos
Potenciais Evocados Auditivos/efeitos dos fármacos , Glicina/farmacologia , Som , Estimulação Acústica/métodos , Estimulação Acústica/psicologia , Administração Oral , Adulto , Análise de Variância , Relação Dose-Resposta a Droga , Método Duplo-Cego , Eletroencefalografia/métodos , Eletromiografia/métodos , Eletrofisiologia/métodos , Potenciais Evocados Auditivos/fisiologia , Glicina/administração & dosagem , Glicinérgicos/administração & dosagem , Glicinérgicos/farmacologia , Humanos , Masculino , Receptores de N-Metil-D-Aspartato/fisiologia , Inquéritos e QuestionáriosRESUMO
BACKGROUND: There is evidence for an adaptive role of the omega -3 fatty acid, docosahexaenoic acid (DHA) during stress. Mechanisms of action may involve regulation of stress mediators, such as the catecholamines and proinflammatory cytokines. Prevention of stress-induced aggression and hostility were demonstrated in a series of clinical trials. This study investigates whether perceived stress is ameliorated by DHA in stressed university staff. METHODS: Subjects that scored > or = 17 on the Perceived Stress Scale were randomised into a 6-week pilot intervention study. The diet reactive group was supplemented with 6 g of fish oil containing 1.5 g per day DHA, while the placebo group was supplemented with 6 g a day of olive oil. The groups were compared with each other and a wider cross sectional study population that did not receive either active or placebo intervention. RESULTS: There was a significant reduction in perceived stress in both the fish oil and the placebo group from baseline. There was also a significant between-group difference between the fish oil group and the no-treatment controls in the rate of stress reduction (p < 0.05). However, there was not a significant between-group difference between the fish oil and the placebo group, nor the placebo group and the control group. These results are discussed in the context of several methodological limitations. The significant stress reductions in both the fish oil and the placebo group are considered in view of statistical regression, an effect likely to have been exaggerated by the time course of the study, a large placebo effect and the possibility of an active effect from the placebo. CONCLUSION: There were significant differences (p < 0.05) in the fish oil group compared with no-treatment controls. This effect was not demonstrated in the placebo group. As a pilot study, it was not sufficiently powered to find the difference between the fish oil group and the placebo group significant. Further work needs to be undertaken to conclusively demonstrate these data trends. However, the findings from this research support the literature in finding a protective or 'adaptogenic' role for omega-3 fatty acids in stress.
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L-Theanine (delta-glutamylethylamide) is one of the predominant amino acids ordinarily found in green tea, and historically has been used as a relaxing agent. The current study examined the acute effects of L-theanine in comparison with a standard benzodiazepine anxiolytic, alprazolam and placebo on behavioural measures of anxiety in healthy human subjects using the model of anticipatory anxiety (AA). Sixteen healthy volunteers received alprazolam (1 mg), L-theanine (200 mg) or placebo in a double-blind placebo-controlled repeated measures design. The acute effects of alprazolam and L-theanine were assessed under a relaxed and experimentally induced anxiety condition. Subjective self-reports of anxiety including BAI, VAMS, STAI state anxiety, were obtained during both task conditions at pre- and post-drug administrations. The results showed some evidence for relaxing effects of L-theanine during the baseline condition on the tranquil-troubled subscale of the VAMS. Alprazolam did not exert any anxiolytic effects in comparison with the placebo on any of the measures during the relaxed state. Neither L-theanine nor alprazalam had any significant anxiolytic effects during the experimentally induced anxiety state. The findings suggest that while L-theanine may have some relaxing effects under resting conditions, neither L-theanine not alprazolam demonstrate any acute anxiolytic effects under conditions of increased anxiety in the AA model.
Assuntos
Alprazolam/uso terapêutico , Ansiolíticos/uso terapêutico , Ansiedade/tratamento farmacológico , Glutamatos/uso terapêutico , Adulto , Método Duplo-Cego , Feminino , Humanos , MasculinoRESUMO
Extracts of Ginkgo biloba and Bacopa monniera have been shown to produce positive effects on cognitive function in healthy subjects. While the exact mechanisms are not known, it has been suggested that antioxidant properties and cholinergic modulation may play a role. In the current study the sub-chronic (2 weeks) and chronic (4 weeks) effects of an extract containing Ginkgo biloba (120 mg) and Bacopa monniera (300 mg) (Blackmores Ginkgo Brahmi) on cognitive function were examined. The study was a randomized, double-blind, placebo-controlled, independent group design in which 85 healthy subjects were allocated to one of two treatment conditions (placebo or combined Ginkgo biloba and Bacopa monniera extract). Testing was conducted at baseline and 2 and 4 weeks post treatment. The results showed that the combined extract relative to placebo did not demonstrate any significant effects on tests investigating a range of cognitive processes including attention, short-term and working memory, verbal learning, memory consolidation, executive processes, planning and problem solving, information processing speed, motor responsiveness and decision making. These findings suggest that at least within the current treatment duration and doses, an extract containing Ginkgo biloba and Bacopa monniera had no cognitive enhancing effects in healthy subjects.
Assuntos
Bacopa , Cognição/efeitos dos fármacos , Ginkgo biloba , Adulto , Idoso , Análise de Variância , Cognição/fisiologia , Método Duplo-Cego , Combinação de Medicamentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos/estatística & dados numéricos , Extratos Vegetais/farmacologia , Folhas de Planta , Estruturas VegetaisRESUMO
Western herbal medicine is the most widely used form of herbal medicine in Australia although Ayurvedic and Chinese herbal medicines are becoming better known. The agricultural production and manufacture of locally grown herbs is, with some exceptions, relatively underdeveloped, as is the research and development of indigenous flora. However, the use of herbal medicine is increasingly becoming mainstream with retail sales of herbal products in Australia estimated to be 200 million dollars. Concurrent with the increase in popularity of herbal medicine with health consumers have come advances in herbal medicine education and regulation. Although small by European standards, research into herbal medicines is increasing, mainly through industry and University-based initiatives.
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The physiological effects and efficacy of dietary intake of antioxidant supplements in humans remains controversial. Experiments involving dietary, often high, intake of a single antioxidant or vitamin may be seriously flawed given the interactive nature of antioxidants in vivo. The present studies were conducted on individuals (35-60 years of age) taking a commercial antioxidant mixture in a double-blind, placebo-controlled, cross-over study. Intake was two capsules per day, for 4 weeks, with a 4-week washout period in between active dose or placebo. Intake of antioxidants was associated with little change in superoxide dismutase activity, but an increase in glutathione peroxidase was noted. Haemolysis of red blood cells (erythrocytes) induced by the free radical generator AAPH was significantly reduced in individuals on antioxidant supplements. In lymphocytes isolated from individuals taking supplements, there was a marked increase, as compared with individuals on placebo, in the synthesis of heat shock protein 70 (hsp70) following heat shock from 37 degrees C to 42.5 degrees C. We conclude that dietary intake of a mixed antioxidant supplement leads to modulation of cellular redox status resulting in decreased oxidative stress and increased ability of lymphocytes to mount a stress response.