Response Monitoring in De Novo Patients with Parkinson's Disease

BACKGROUND: Parkinson's disease (PD) is accompanied by dysfunctions in a variety of cognitive processes. One of these is error processing, which depends upon phasic decreases of medial prefrontal dopaminergic activity. Until now, there is no study evaluating these processes in newly diagnosed, untreated patients with PD ("de novo PD"). METHODOLOGY/PRINCIPAL FINDINGS: Here we report large changes in performance monitoring processes using event-related potentials (ERPs) in de novo PD-patients. The results suggest that increases in medial frontal dopaminergic activity after an error (Ne) are decreased, relative to age-matched controls. In contrast, neurophysiological processes reflecting general motor response monitoring (Nc) are enhanced in de novo patients. CONCLUSIONS/SIGNIFICANCE: It may be hypothesized that the Nc-increase is at costs of dopaminergic activity after an error; on a functional level errors may not always be detected and correct responses sometimes be misinterpreted as errors. This pattern differs from studies examining patients with a longer history of PD and may reflect compensatory processes, frequently occurring in pre-manifest stages of PD. From a clinical point of view the clearly attenuated Ne in the de novo PD patients may prove a useful additional tool for the early diagnosis of basal ganglia dysfunction in PD

The contributions of muscarinic receptors and changes in plasma aldosterone levels to the anti-hypertensive effect of Tulbaghia violacea

Background: Tulbaghia violacea Harv. (Alliaceae) is used to treat various ailments, including hypertension (HTN) in South Africa. This study aims to evaluate the contributions of muscarinic receptors and changes in plasma aldosterone levels to its anti-hypertensive effect. Methods: In the acute experiments, methanol leaf extracts (MLE) of T. violacea (30–120 mg/kg), muscarine (0.16 -10 μg/kg), and atropine (0.02 - 20.48 mg/kg), and/or the vehicle (dimethylsulfoxide (DMSO) and normal saline (NS)) were respectively and randomly administered intravenously in a group of spontaneously hypertensive (SHR) weighing 300 to 350 g and aged less than 5 months. Subsequently, T. violacea (60 mg/kg) or muscarine (2.5 μg/kg) was infused into eight SHRs, 20 min after atropine (5.12 mg/kg) pre-treatment. In the chronic (21 days) experiments, the SHRs were randomly divided into three groups, and given the vehicle (0.2 ml/day of DMSO and NS), T. violacea (60 mg/kg/day) and captopril (10 mg/kg/day) respectively into the peritoneum, to investigate their effects on blood pressure (BP), heart rate (HR), and plasma aldosterone levels. Systolic BP and HR were measured using tail-cuff plethysmography during the intervention. BP and HR were measured via a pressure transducer connecting the femoral artery and the Powerlab at the end of each intervention in the acute experiment; and on day 22 in the chronic experiment. Results: In the acute experiments, T. violacea, muscarine, and atropine significantly (p < 0.05) reduced BP dose-dependently. T. violacea and muscarine produced dose-dependent decreases in HR, while the effect of atropine on HR varied. After atropine pre-treatment, dose-dependent increases in BP and HR were observed with T. violacea; while the BP and HR effects of muscarine were nullified. In the chronic experiments, the T. violaceatreated and captropril-treated groups had signicantly lower levels of aldosterone in plasma when compared to vehicle-treated group. Compared to the vehicle-treated group, significant reduction in BP was only seen in the captopril-treated group; while no difference in HR was observed among the groups. Conclusion: The results obtained in this study suggest that stimulation of the muscarinic receptors and a reduction in plasma aldosterone levels contribute to the anti-hypertesive effect of T. violacea.IS

Electrophysiological evidence of enhanced performance monitoring in recently abstinent alcoholic men

RATIONALE: Chronic alcoholism is associated with mild to moderate cognitive impairment. Under certain conditions, impairment can be ameliorated by invoking compensatory processes. OBJECTIVE: To identify electrophysiological mechanisms of such compensation that would be required to resolve response conflict. METHODS: 14 abstinent alcoholic men and 14 similarly aged control men performed a variation of the Eriksen flanker task during an electroencephalography (EEG) recording to examine whether alcoholics could achieve and maintain control-level performance and whether EEG markers could identify evidence for the action of compensatory processes in the alcoholics. Monitoring processes engaged following a response were indexed by the correct related negativity (CRN) and error related negativity (ERN), two medial-frontal negative event-related potentials. RESULTS: The alcoholics were able to perform at control levels on accuracy and reaction time (RT). Alcoholics generated larger ERN amplitudes following incorrect responses and larger CRNs following correct responses than controls. Both groups showed evidence of post-error slowing. Larger CRN amplitudes in the alcoholics were related to longer RTs. Also observed in the alcoholics was an association between smaller CRN amplitudes and length of sobriety, suggesting a normalization of monitoring activity with extended abstinence. CONCLUSIONS: To the extent that greater amplitude of these electrophysiological markers of performance monitoring indexes greater resource allocation and performance compensation, the larger amplitudes observed in the alcoholic than control group support the view that elevated performance monitoring enables abstinent alcoholics to overcome response conflict, as was evident in their control-level performance

Telephone Consultation for Improving Health of People Living with or at Risk of HIV: A Systematic Review

BACKGROUND: Low cost, effective interventions are needed to deal with the major global burden of HIV/AIDS. Telephone consultation offers the potential to improve health of people living with HIV/AIDS cost-effectively and to reduce the burden on affected people and health systems. The aim of this systematic review was to assess the effectiveness of telephone consultation for HIV/AIDS care. METHODS: We undertook a comprehensive search of peer-reviewed and grey literature. Two authors independently screened citations, extracted data and assessed the quality of randomized controlled trials which compared telephone interventions with control groups for HIV/AIDS care. Telephone interventions were voice calls with landlines or mobile phones. We present a narrative overview of the results as the obtained trials were highly heterogeneous in design and therefore the data could not be pooled for statistical analysis. RESULTS: The search yielded 3321 citations. Of these, nine studies involving 1162 participants met the inclusion criteria. The telephone was used for giving HIV test results (one trial) and for delivering behavioural interventions aimed at improving mental health (four trials), reducing sexual transmission risk (one trial), improving medication adherence (two trials) and smoking cessation (one trial). Limited effectiveness of the intervention was found in the trial giving HIV test results, in one trial supporting medication adherence and in one trial for smoking cessation by telephone. CONCLUSIONS: We found some evidence of the benefits of interventions delivered by telephone for the health of people living with HIV or at risk of HIV. However, only limited conclusions can be drawn as we only found nine studies for five different interventions and they mainly took place in the United States. Nevertheless, given the high penetration of low-cost mobile phones in countries with high HIV endemicity, more evidence is needed on how telephone consultation can aid in the delivery of HIV prevention, treatment and care

Waist circumference in the prediction of obesity-related adverse pregnancy outcomes Circunferência da cintura na predição de desfechos adversos da gestação relacionados à obesidade

The aim of this study is to evaluate the diagnostic properties of waist circumference in the prediction of obesity-related gestational outcomes. Pregnant women 20 years or older were consecutively enrolled in six Brazilian State capitals from 1991 to 1995. Weight, height, and waist circumference were measured and an oral glucose tolerance test was performed. Patients were followed through childbirth by chart review. Diagnostic performance for the different outcomes, as measured by area under the receiver operating characteristic (ROC) curve, was estimated through logistic regression. Areas under the ROC curve (95%CI) for waist circumference were 0.621(0.589-0.652) for gestational diabetes, 0.640 (0.588-0.692) for preeclampsia, and 0.645(0.617-0.673) for macrosomia. These areas were similar to those for BMI (p > 0.05). A waist circumference of 82cm jointly maximized sensitivity (63%) and specificity (57%). Cutoff points of 23kg/m² for pre-pregnancy BMI and 26kg/m² for BMI at enrollment produced similar diagnostic properties. In conclusion, waist circumference predicts obesity-related adverse pregnancy outcomes at least as well as BMI.<br>O objetivo deste estudo é avaliar as propriedades diagnósticas da circunferência da cintura na predição de desfechos adversos da gestação relacionados à obesidade. Gestantes com 20 ou mais anos de idade, foram arroladas consecutivamente, entre 20 e 28 semanas de gestação, em seis capitais do Brasil, entre 1991 e 1995. Peso, altura e circunferência da cintura foram aferidos e um teste de tolerância à glicose foi realizado. As pacientes foram acompanhadas até o parto através de revisão de prontuários. Propriedades diagnósticas para os diferentes desfechos, mensurados através da área sob a curva Receiver Operator Charactheristic (ROC), foram estimadas por regressão logística. Áreas (IC95%) sob as curvas ROC para a cintura foram 0,621 (0,589-0,652) para diabetes gestacional, 0,640 (0,588-0,692) para pré-eclâmpsia e 0,645 (0,617-0,673) para macrossomia. Estas áreas foram similares às encontradas para o IMC (p > 0,05). A cintura de 82cm apresentou máximas sensibilidade (63%) e especificidade (57%). Um ponto de corte de 23kg/m² para o IMC pré-gestacional e de 26kg/m² para o IMC no arrolamento produziu propriedades diagnósticas semelhantes. A medida da circunferência da cintura prediz complicações como diabete gestacional, pré-eclâmpsia e macrossomia fetal tão bem quanto o IMC