Methylphenidate: Brain Gain for the Epilepsy Drain.
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ABSTRACT:
SUBMITTER: Lee JW
PROVIDER: S-EPMC5486423 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BACKGROUND: Medical emigration from developing to developed countries is a well established phenomenon of substantial importance. Though Libya is classified as an upper-middle income country, it has been affected by this trend. This study was undertaken to identify some of the possible reasons behind the emigration of Libyan doctors and factors that might motivate them to return. FINDINGS: Seventy-four completed questionnaires were analysed. Median age of the respondents was 43 years (33-60) and median duration of stay outside Libya was 15 years (6-29). Most of the participants were resident in Europe (66%). The desire to further their education and research was the main reason given by 88% of the respondents for leaving Libya, while 50% of them gave that as the main reason for staying abroad. One-third of the respondents (31%) cited economic factors as the main reason for not returning. None of the respondents ruled out returning to Libya, and about half of them stated that they definitely or probably will return to Libya. 58% ranked reform of the Libyan health system as the most important reason that could induce them to return to Libya. CONCLUSION: The study shows that reforming the health care system in Libya might induce some of the physicians who moved abroad mainly for educational and economic reasons to return to Libya to practice medicine.
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Project description:Graphene devices for radio frequency (RF) applications are of great interest due to their excellent carrier mobility and saturation velocity. However, the insufficient current saturation in graphene field effect transistors (FETs) is a barrier preventing enhancements of the maximum oscillation frequency and voltage gain, both of which should be improved for RF transistors. Achieving a high output resistance is therefore a crucial step for graphene to be utilized in RF applications. In the present study, we report high output resistances and voltage gains in graphene-on-silicon (GoS) FETs. This is achieved by utilizing bare silicon as a supporting substrate without an insulating layer under the graphene. The GoSFETs exhibit a maximum output resistance of 2.5 MΩ∙μm, maximum intrinsic voltage gain of 28 dB, and maximum voltage gain of 9 dB. This method opens a new route to overcome the limitations of conventional graphene-on-insulator (GoI) FETs and subsequently brings graphene electronics closer to practical usage.
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Project description:ObjectiveTo evaluate the potential efficacy of immediate-release methylphenidate (MPH) for treating cognitive deficits in epilepsy.MethodsThis was a double-blind, randomized, single-dose, 3-period crossover study in patients with epilepsy and chronic cognitive complaints comparing the effects of placebo and MPH 10 and 20 mg given 1 week apart. Cognitive outcome was evaluated on the basis of an omnibus z score calculated from performance on the Conners Continuous Performance Test 3 (ability to discriminate between target and nontarget stimuli [d'] and hit reaction time standard deviation), Symbol-Digit Modalities Test, and Medical College of Georgia Paragraph Memory Test. Adverse events and seizure frequency were monitored. An open-label follow-up is reported elsewhere.ResultsThirty-five adult patients with epilepsy participated, of whom 31 finished. Demographics included the following: mean age = 35.3 years (range 20-62 years), 13 men and 18 women, and baseline seizure frequency of 2.8 per month. Epilepsy types were focal (n = 24), generalized (n = 6), or unclassified (n = 1). Mean epilepsy duration was 12.5 years. A statistically significant performance benefit was present at both 10-mg (p = 0.030) and 20-mg (p = 0.034) MPH doses. No seizures were associated with either MPH dose. Adverse effects leading to withdrawal included cognitive "fogginess" (n = 1 on 20 mg), anxiety/agitation (n = 1 on 10 mg), and tachycardia (n = 1). One participant was lost to follow-up after one 20-mg dose without side effect.ConclusionsThis single-dose study suggests that MPH may be effective in ameliorating some cognitive deficits in patients with epilepsy. Additional studies are required.Clinicaltrialsgov identifierNCT02178995.Classification of evidenceThis study provides Class II evidence that single doses of MPH improve cognitive performance on some measures of attention and processing speed in patients with epilepsy and cognitive complaints.
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Project description:The origin of neural hyperexcitability underlying idiopathic generalized epilepsy (IGE) is not known. The objective of this study is to identify evidence of hyperexcitability in precisely measured visual evoked responses and to understand the nature of changes in excitation and inhibition that lead to altered responses in human patients with IGE.Steady-state visual-evoked potentials (VEPs) to contrast reversing gratings were recorded over a wide range of stimulus contrast. VEPs were analyzed at the pattern reversal rate using spectral analysis. Ten patients with IGE and 13 healthy subjects participated. All subjects had normal visual acuity and had no history of photic-induced seizures or photoparoxysmal electroencephalograph (EEG) activity.At a group level, the amplitude of visual responses did not saturate at high stimulus contrast in patients, as it did in the control subjects. This reflects an abnormality in neuronal gain control. The VEPs did not have sufficient power to reliably distinguish patients from controls at an individual level. Parametric modeling using a standard gain control framework showed that the abnormality lay in reduced inhibition from neighboring neurons rather than increased excitatory response to the stimulus.Visual evoked responses reveal changes in a fundamental mechanism regulating neuronal sensitivity. These changes may give rise to hyperexcitability underlying generalized epilepsy.
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Project description:Dopamine plays an important role in goal-directed behavior, through its modulatory influence on striatal neurons. It is unclear whether tonic dopamine levels, which regulate the vigor of acting, interact with the phasic dopamine response to reward that drives instrumental behavior. In a randomized placebo-controlled study in healthy volunteers, we show that methylphenidate, a drug that increases tonic dopamine levels, systematically reduced striatal phasic BOLD responses to gain and loss in a gambling task as measured with fMRI. It also increased response vigor and reward expectancy-related BOLD signals in the ventral striatum. These findings suggest that striatal tonic dopamine levels constitute an average reward expectation signal that modulates the phasic dopaminergic response to reward. This offers opportunities for treatment of behavioral disorders associated with abnormal reward sensitivity.
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Project description:The Russian invasion of Ukraine has caused large scale destruction, significant loss of life, and the displacement of millions of people. Besides those fleeing direct conflict in Ukraine, many individuals in Russia are also thought to have moved to third countries. In particular the exodus of skilled human capital, sometimes called brain drain, out of Russia may have a significant effect on the course of the war and the Russian economy in the long run. Yet quantifying brain drain, especially during crisis situations is generally difficult. This hinders our ability to understand its drivers and to anticipate its consequences. To address this gap, I draw on and extend a large scale dataset of the locations of highly active software developers collected in February 2021, one year before the invasion. Revisiting those developers that had been located in Russia in 2021, I confirm an ongoing exodus of developers from Russia in snapshots taken in June and November 2022. By November 11.1% of Russian developers list a new country, compared with 2.8% of developers from comparable countries in the region but not directly involved in the conflict. 13.2% of Russian developers have obscured their location (vs. 2.4% in the comparison set). Developers leaving Russia were significantly more active and central in the collaboration network than those who remain. This suggests that many of the most important developers have already left Russia. In some receiving countries the number of arrivals is significant: I estimate an increase in the number of local software developers of 42% in Armenia, 60% in Cyprus and 94% in Georgia.Supplementary informationThe online version contains supplementary material available at 10.1140/epjds/s13688-023-00389-3.
| S-EPMC10184088 | biostudies-literature
Project description:Methylphenidate (MPH) is an indirect dopaminergic and noradrenergic agonist that is used to treat attention deficit hyperactivity disorder and that has shown therapeutic potential in neuropsychiatric diseases such as depression, dementia, and Parkinson's disease. While effects of MPH on task-induced brain activation have been investigated, little is known about how MPH influences the resting brain. To investigate the effects of 40 mg of oral MPH on intrinsic functional connectivity, we used resting state fMRI in 54 healthy male subjects in a double-blind, randomized, placebo-controlled study. Functional connectivity analysis employing ICA revealed seven resting state networks (RSN) of interest. Connectivity strength between the dorsal attention network and the thalamus was increased after MPH intake. Other RSN located in association cortex areas, such as the left and right frontoparietal networks and the executive control network, showed MPH-induced connectivity increase to sensory-motor and visual cortex regions and connectivity decrease to cortical and subcortical components of cortico-striato-thalamo-cortical circuits (CST). RSN located in sensory-motor cortex areas showed the opposite pattern with MPH-induced connectivity increase to CST components and connectivity decrease to sensory-motor and visual cortex regions. Our results provide evidence that MPH does not only alter intrinsic connectivity between brain areas involved in sustained attention, but that it also induces significant changes in the cortico-cortical and cortico-subcortical connectivity of many other cognitive and sensory-motor RSN.
| S-EPMC6869774 | biostudies-literature
Project description:The 2004/2007 European Union (EU) enlargement by 12 member states offers a unique opportunity to quantify the impact of EU efforts to expand and integrate the scientific competitiveness of the European Research Area (ERA). We apply two causal estimation schemes to cross-border collaboration data extracted from millions of academic publications from 1996 to 2012, which are disaggregated across 14 subject areas and 32 European countries. Our results illustrate the unintended consequences following the 2004/2007 enlargement, namely, its negative impact on cross-border collaboration in science. First, we use the synthetic control method to show that levels of European cross-border collaboration would have been higher without EU enlargement, despite the 2004/2007 EU entrants gaining access to EU resources incentivizing cross-border integration. Second, we implement a difference-in-difference panel regression, incorporating official intra-European high-skilled mobility statistics, to identify migration imbalance-principally from entrant to incumbent EU member states-as a major factor underlying the divergence in cross-border integration between Western and Eastern Europe. These results challenge central tenets underlying ERA integration policies that unifying labor markets will increase the international competitiveness of the ERA, thereby calling attention to the need for effective home-return incentives and policies.
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Project description:BackgroundAdults with attention-deficit/hyperactivity disorder (ADHD) are at increased risk for both cigarette smoking and being overweight or obese. Although smoking cessation tends to result in weight increase, potentially initiating or exacerbating weight problems, adults with ADHD who are treated with osmotic release oral system methylphenidate (OROS-MPH) tend to lose weight. It is unclear how the use of OROS-MPH during a smoking-cessation attempt might affect the typical weight gain that accompanies cessation.MethodWe examined changes in weight and hunger during a smoking-cessation attempt in 215 adults with ADHD who completed a multisite, randomized, controlled trial and were randomized to either OROS-MPH (n = 107) or placebo (n = 108) (NCT #00253747). Both groups also received open-label transdermal nicotine replacement and counseling.ResultsParticipants who received OROS-MPH lost an average of 1.6% of their body weight during the 11-week study, whereas those who received placebo gained an average of 1.3% of their weight (p < .001). Hunger ratings were lower in the OROS-MPH group (M = 1.1, SD = 0.8) than in the placebo group (M = 1.6, SD = 0.9; p < .001).ConclusionsThe use of OROS-MPH during a smoking-cessation attempt prevents weight gain in adults with ADHD who substantially reduce or quit smoking. The potential utility of OROS-MPH in individuals with ADHD who are attempting to quit smoking and for whom weight gain would be problematic warrants further research.
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