Presubiculum stimulation in vivo evokes distinct oscillations in superficial and deep entorhinal cortex layers in chronic epileptic rats

The characteristic cell loss in layer III of the medial entorhinal area (MEA-III) in human mesial temporal lobe epilepsy is reproduced in the rat kainate model of the disease. To understand how this cell loss affects the functional properties of the MEA, we investigated whether projections from the presubiculum (prS), providing a main input to the MEA-III, are altered in this epileptic rat model. Injections of an anterograde tracer in the prS revealed bilateral projection fibers mainly to the MEA-III in both control and chronic epileptic rats. We further examined the prS-MEA circuitry using a 16-channel electrode probe covering the MEA in anesthetized control and chronic epileptic rats. With a second 16-channel probe, we recorded signals in the hippocampus. Current source density analysis indicated that, after prS double-pulse stimulation, afterdischarges in the form of oscillations (20-45 Hz) occurred that were confined to the superficial layers of the MEA in all epileptic rats displaying MEA-III neuronal loss. Slower oscillations (theta range) were occasionally observed in the deep MEA layers and the dentate gyrus. This kind of oscillation was never observed in control rats. We conclude that dynamical changes occur in an extensive network within the temporal lobe in epileptic rats, manifested as different kinds of oscillations, the characteristics of which depend on local properties of particular subareas. These findings emphasize the significance of the entorhinal cortex in temporal lobe epilepsy and suggest that the superficial cell layers could play an important role in distributing oscillatory activity.status: publishe

Immunisation coverage and annual report National Immunisation Programme in the Netherlands 2016

Het RIVM beschrijft jaarlijks de ontwikkelingen binnen het Rijksvaccinatieprogramma (RVP), zowel inhoudelijk als organisatorisch. Vanaf dit jaar zijn de belangrijkste gebeurtenissen en de ontwikkelingen op het gebied van de vaccinatiegraad gebundeld. Belangrijke gebeurtenissen In 2016 waren er geen opvallende uitbraken van RVP-ziekten. Wel stijgt sinds oktober 2015 het aantal patiënten met meningokokkenziekte W, terwijl in het RVP tegen meningokokkenziekte C wordt ingeënt. Opvallend was het stevige debat dat in november 2016 in diverse media is gevoerd tussen voor- en tegenstanders van vaccinatie. Verder heeft het RIVM factsheets gemaakt voor zowel professionals als het publiek met informatie over vaccinaties tegen ziekten die wel beschikbaar zijn maar niet in het RVP zijn opgenomen. Voorbeelden zijn waterpokken, gordelroos en het rotavirus (www.rivm.nl/vaccinaties). Vaccinatiegraad De vaccinatiegraad, oftewel het aandeel zuigelingen, kleuters en schoolkinderen dat de vaccinaties uit het RVP krijgt, is nog steeds hoog. De vaccinatiegraad voor bof, mazelen en rodehond (BMR) daalt al een paar jaar licht. De norm van 95 procent van de Wereldgezondheidsorganisatie (WHO), die nodig is om mazelen uit te bannen, wordt in Nederland bij de eerste BMR-vaccinatie niet meer gehaald. Voor de tweede BMR-vaccinatie was dit al langer zo. Ook bij andere vaccinaties in het RVP is een lichte daling te zien. De deelname aan de HPV-vaccinatie tegen baarmoederhalskanker is voor het eerst afgenomen, van 61 naar 53 procent. Een hoge vaccinatiegraad zorgt ervoor dat kwetsbare en (nog) niet gevaccineerde kinderen tegen ziekten worden beschermd (groepsbescherming). Een dalende vaccinatiegraad vergroot de kans dat in de toekomst ziekten zoals mazelen uitbreken.The RIVM annually describes the developments within the Dutch National Immunisation Programme (NIP), both substantively and organisationally. From this year, the most important events and developments in the field of immunisation coverage have been bundled. Important events In 2016, there were no significant outbreaks of NIP diseases. However, since October 2015, the number of meningococcal disease patients by a different serogroup (W) than the serogroup C which is vaccinated against within the NIP, has risen. Striking was the vigorous debate that was conducted in various media in November 2016 between advocates and opponents of immunisation. Furthermore, the RIVM has made factsheets for professionals as well as the public with information on vaccines against diseases that are available but not included in the NIP. Examples include varicella, herpes zoster and rotavirus (www.rivm.nl/vaccinations). Immunisation coverage The immunisation coverage, i.e. the proportion of newborns, toddlers and schoolchildren who receive vaccinations within the NIP is still high. The immunisation coverage for mumps, measles and rubella (MMR) has declined slightly for a few years. The 95 per cent threshold of the World Health Organization (WHO) needed to eliminate measles is no longer achieved in the Netherlands for the first MMR vaccination. For the second MMR vaccination this has been for longer. Also for other NIP vaccinations there is a slight decrease in participation. The participation in HPV vaccination against cervical cancer has decreased for the first time, from 61 to 53 per cent. A high immunisation coverage ensures that vulnerable and not (yet) vaccinated children are protected against diseases (herd protection). A decreasing immunisation coverage increases the likelihood that diseases such as measles cause outbreaks in the future.Ministerie van VW

Seizure-mediated iron accumulation and dysregulated iron metabolism after status epilepticus and in temporal lobe epilepsy

Neuronal dysfunction due to iron accumulation in conjunction with reactive oxygen species (ROS) could represent an important, yet underappreciated, component of the epileptogenic process. However, to date, alterations in iron metabolism in the epileptogenic brain have not been addressed in detail. Iron-related neuropathology and antioxidant metabolic processes were investigated in resected brain tissue from patients with temporal lobe epilepsy and hippocampal sclerosis (TLE-HS), post-mortem brain tissue from patients who died after status epilepticus (SE) as well as brain tissue from the electrically induced SE rat model of TLE. Magnetic susceptibility of the presumed seizure-onset zone from three patients with focal epilepsy was compared during and after seizure activity. Finally, the cellular effects of iron overload were studied in vitro using an acute mouse hippocampal slice preparation and cultured human fetal astrocytes. While iron-accumulating neurons had a pyknotic morphology, astrocytes appeared to acquire iron-sequestrating capacity as indicated by prominent ferritin expression and iron retention in the hippocampus of patients with SE or TLE. Interictal to postictal comparison revealed increased magnetic susceptibility in the seizure-onset zone of epilepsy patients. Post-SE rats had consistently higher hippocampal iron levels during the acute and chronic phase (when spontaneous recurrent seizures are evident). In vitro, in acute slices that were exposed to iron, neurons readily took up iron, which was exacerbated by induced epileptiform activity. Human astrocyte cultures challenged with iron and ROS increased their antioxidant and iron-binding capacity, but simultaneously developed a pro-inflammatory phenotype upon chronic exposure. These data suggest that seizure-mediated, chronic neuronal iron uptake might play a role in neuronal dysfunction/loss in TLE-HS. On the other hand, astrocytes sequester iron, specifically in chronic epilepsy. This function might transform astrocytes into a highly resistant, pro-inflammatory phenotype potentially contributing to pro-epileptogenic inflammatory processes

Meningokokkenziekte in Nederland : Achtergrondinformatie voor de Gezondheidsraad

Meningococcal disease is a very serious infectious disease caused by a bacterium, the meningococcus. There are different types of meningococcus; people become ill mainly from the B, C, W and Y serogroups. Since 2002, vaccination against serogroup C meningococcal disease has been included in the National Immunisation Programme for children of 14 months. As a result, serogroup C meningococcal disease has virtually disappeared. Vaccines against serogroup B have recently become available. In addition, since 2015, there has been a rapid increase in serogroup W meningococcal disease. Multi-component vaccines are available against A, C, W and Y serogroups. Based on these developments, among others, the Health Council will advise the Minister for Health, Welfare and Sport on whether and how the current immunisation programme against meningococcal disease should be adapted. To this end, RIVM has collected background information and recent data on meningococcal disease in the Netherlands. It includes the number of people in the Netherlands who become ill each year, the efficacy and safety of the vaccines, and what the public thinks about vaccination against invasive meningococcal disease. The infection causes a severe medical condition such as meningitis or blood poisoning, which can rapidly develop into shock, frequently causing death. The disease often begins with flu-like symptoms and fever which subsequently worsen very rapidly. The infection is relatively rare in the Netherlands; there are currently 100 to 150 patients a year. Five to ten percent of these patients die despite antibiotics and intensive care. Thirty percent of the patients are left with lifelong impairments such as hearing loss, limb amputation or epilepsy. Meningococcal disease is most common in children under the age of 5, adolescents and the elderly.Meningokokkenziekte is een zeer ernstige infectieziekte die veroorzaakt wordt door een bacterie, de meningokok. Er zijn verschillende typen meningokokken; mensen worden vooral ziek van de serogroepen B, C, W en Y. Vaccinatie tegen meningokokkenziekte serogroep C is in Nederland sinds 2002 opgenomen in het Rijksvaccinatieprogramma voor kinderen van 14 maanden. Hierdoor komt meningokokkenziekte door serogroep C nauwelijks meer voor. Sinds kort zijn vaccins beschikbaar tegen serogroep B. Daarnaast is er sinds 2015 een snelle toename in meningokokkenziekte door serogroep W. Er zijn combinatievaccins beschikbaar tegen serogroep A, C, W en Y. Vanwege ondermeer deze ontwikkelingen gaat de Gezondheidsraad de minister van VWS adviseren of, en op welke manier, het huidige vaccinatieprogramma tegen meningokokkenziekte aangepast moet worden. Daartoe heeft het RIVM achtergrondinformatie en recente data over meningokokkenziekte in Nederland verzameld. Het gaat onder meer om het aantal mensen in Nederland dat jaarlijks ziek wordt, de effectiviteit en veiligheid van de vaccins, en hoe het publiek denkt over vaccinatie tegen invasieve meningokokkenziekte. De infectie geeft een ernstig ziektebeeld zoals hersenvliesontsteking of een bloedvergiftiging, die zich snel kan ontwikkelen tot een shock waar veel mensen aan overlijden. De ziekte begint vaak met griepachtige verschijnselen en koorts die vervolgens zeer snel verergeren. De infectie is in Nederland relatief zeldzaam; op dit moment zijn er 100 tot 150 patiënten per jaar. Van deze patiënten overlijdt 5-10 procent ondanks antibiotica en intensieve zorg. 30 procent van de patiënten houdt er levenslang beperkingen aan over zoals gehoorverlies, amputatie van een ledemaat of epilepsie. Meningokokkenziekte komt het meest voor bij kinderen jonger dan 5 jaar, adolescenten en ouderenMinisterie van VW

(R)-[11C]Verapamil PET studies to assess changes in P-glycoprotein expression and functionality in rat blood-brain barrier after exposure to kainate-induced status epilepticus

<p>Abstract</p> <p>Background</p> <p>Increased functionality of efflux transporters at the blood-brain barrier may contribute to decreased drug concentrations at the target site in CNS diseases like epilepsy. In the rat, pharmacoresistant epilepsy can be mimicked by inducing status epilepticus by intraperitoneal injection of kainate, which leads to development of spontaneous seizures after 3 weeks to 3 months. The aim of this study was to investigate potential changes in P-glycoprotein (P-gp) expression and functionality at an early stage after induction of status epilepticus by kainate.</p> <p>Methods</p> <p><it>(R)</it>-[¹¹C]verapamil, which is currently the most frequently used positron emission tomography (PET) ligand for determining P-gp functionality at the blood-brain barrier, was used in kainate and saline (control) treated rats, at 7 days after treatment. To investigate the effect of P-gp on <it>(R)</it>-[¹¹C]verapamil brain distribution, both groups were studied without or with co-administration of the P-gp inhibitor tariquidar. P-gp expression was determined using immunohistochemistry in post mortem brains. <it>(R)</it>-[¹¹C]verapamil kinetics were analyzed with approaches common in PET research (Logan analysis, and compartmental modelling of individual profiles) as well as by population mixed effects modelling (NONMEM).</p> <p>Results</p> <p>All data analysis approaches indicated only modest differences in brain distribution of <it>(R)</it>-[¹¹C]verapamil between saline and kainate treated rats, while tariquidar treatment in both groups resulted in a more than 10-fold increase. NONMEM provided most precise parameter estimates. P-gp expression was found to be similar for kainate and saline treated rats.</p> <p>Conclusions</p> <p>P-gp expression and functionality does not seem to change at early stage after induction of anticipated pharmacoresistant epilepsy by kainate.</p

Effects of rapamycin and curcumin on inflammation and oxidative stress in vitro and in vivo - in search of potential anti-epileptogenic strategies for temporal lobe epilepsy

Background: Previous studies in various rodent epilepsy models have suggested that mammalian target of rapamycin (mTOR) inhibition with rapamycin has anti-epileptogenic potential. Since treatment with rapamycin produces unwanted side effects, there is growing interest to study alternatives to rapamycin as anti-epileptogenic drugs. Therefore, we investigated curcumin, the main component of the natural spice turmeric. Curcumin is known to have anti-inflammatory and anti-oxidant effects and has been reported to inhibit the mTOR pathway. These properties make it a potential anti-epileptogenic compound and an alternative for rapamycin.Methods: To study the anti-epileptogenic potential of curcumin compared to rapamycin, we first studied the effects of both compounds on mTOR activation, inflammation, and oxidative stress in vitro, using cell cultures of human fetal astrocytes and the neuronal cell line SH-SY5Y. Next, we investigated the effects of rapamycin and intracerebrally applied curcumin on status epilepticus (SE)—induced inflammation and oxidative stress in hippocampal tissue, during early stages of epileptogenesis in the post-electrical SE rat model for temporal lobe epilepsy (TLE).Results: Rapamycin, but not curcumin, suppressed mTOR activation in cultured astrocytes. Instead, curcumin suppressed the mitogen-activated protein kinase (MAPK) pathway. Quantitative real-time PCR analysis revealed that curcumin, but not rapamycin, reduced the levels of inflammatory markers IL-6 and COX-2 in cultured astrocytes that were challenged with IL-1β. In SH-SY5Y cells, curcumin reduced reactive oxygen species (ROS) levels, suggesting anti-oxidant effects. In the post-SE rat model, however, treatment with rapamycin or curcumin did not suppress the expression of inflammatory and oxidative stress markers 1 week after SE.Conclusions: These results indicate anti-inflammatory and anti-oxidant properties of curcumin, but not rapamycin, in vitro. Intracerebrally applied curcumin modified the MAPK pathway in vivo at 1 week after SE but failed to produce anti-inflammatory or anti-oxidant effects. Future studies should be directed to increasing the bioavailability of curcumin (or related compounds) in the brain to assess its anti-epileptogenic potential in vivo

Neurocognitive outcome and mental health in children with tyrosinemia type 1 and phenylketonuria: A comparison between two genetic disorders affecting the same metabolic pathway

Tyrosinemia type 1 (TT1) and phenylketonuria (PKU) are both inborn errors of phenylalanine–tyrosine metabolism. Neurocognitive and behavioral outcomes have always featured in PKU research but received less attention in TT1 research. This study aimed to investigate and compare neurocognitive, behavioral, and social outcomes of treated TT1 and PKU patients. We included 33 TT1 patients (mean age 11.24 years; 16 male), 31 PKU patients (mean age 10.84; 14 male), and 58 age- and gender-matched healthy controls (mean age 10.82 years; 29 male). IQ (Wechsler-subtests), executive functioning (the Behavioral Rating Inventory of Executive Functioning), mental health (the Achenbach-scales), and social functioning (the Social Skills Rating System) were assessed. Results of TT1 patients, PKU patients, and healthy controls were compared using Kruskal–Wallis tests with post-hoc Mann–Whitney U tests. TT1 patients showed a lower IQ and poorer executive functioning, mental health, and social functioning compared to healthy controls and PKU patients. PKU patients did not differ from healthy controls regarding these outcome measures. Relatively poor outcomes for TT1 patients were particularly evident for verbal IQ, BRIEF dimensions “working memory”, “plan and organize” and “monitor”, ASEBA dimensions “social problems” and “attention problems”, and for the SSRS “assertiveness” scale (all p values <0.001). To conclude, TT1 patients showed cognitive impairments on all domains studied, and appeared to be significantly more affected than PKU patients. More attention should be paid to investigating and monitoring neurocognitive outcome in TT1 and research should focus on explaining the underlying pathophysiological mechanism

Hydropower plans in eastern and southern Africa increase risk of concurrent climate-related electricity supply disruption

Hydropower comprises a significant and rapidly expanding proportion of electricity production in eastern and southern Africa. In both regions, hydropower is exposed to high levels of climate variability and regional climate linkages are strong, yet an understanding of spatial interdependences is lacking. Here we consider river basin configuration and define regions of coherent rainfall variability using cluster analysis to illustrate exposure to the risk of hydropower supply disruption of current (2015) and planned (2030) hydropower sites. Assuming completion of the dams planned, hydropower will become increasingly concentrated in the Nile (from 62% to 82% of total regional capacity) and Zambezi (from 73% to 85%) basins. By 2030, 70% and 59% of total hydropower capacity will be located in one cluster of rainfall variability in eastern and southern Africa, respectively, increasing the risk of concurrent climate-related electricity supply disruption in each region. Linking of nascent regional electricity sharing mechanisms could mitigate intraregional risk, although these mechanisms face considerable political and infrastructural challenges

Levetiracetam Reverses Synaptic Deficits Produced by Overexpression of SV2A

Levetiracetam is an FDA-approved drug used to treat epilepsy and other disorders of the nervous system. Although it is known that levetiracetam binds the synaptic vesicle protein SV2A, how drug binding affects synaptic functioning remains unknown. Here we report that levetiracetam reverses the effects of excess SV2A in autaptic hippocampal neurons. Expression of an SV2A-EGFP fusion protein produced a ∼1.5-fold increase in synaptic levels of SV2, and resulted in reduced synaptic release probability. The overexpression phenotype parallels that seen in neurons from SV2 knockout mice, which experience severe seizures. Overexpression of SV2A also increased synaptic levels of the calcium-sensor protein synaptotagmin, an SV2-binding protein whose stability and trafficking are regulated by SV2. Treatment with levetiracetam rescued normal neurotransmission and restored normal levels of SV2 and synaptotagmin at the synapse. These results indicate that changes in SV2 expression in either direction impact neurotransmission, and suggest that levetiracetam may modulate SV2 protein interactions