Downward migration and transfer to plants of radiocaesium in Scottish soil profiles

Following the accident at the nuclear power plant in Chernobyl in 1986, great volumes of 137Cs were distributed over large parts of the former Soviet Union and Europe. Over Scotland, radiocaesium was deposited as wet deposition. Due to the relatively long physical half-life of 30 years, there are still measurable activity concentrations in the natural environment. This study was made on two organic soils, Knockandy Hill and Rora Moss, situated in the eastern part of the central highlands of Scotland. At these two sites, studies on migration and transfer between soil and plants were conducted. The aim of the thesis was to present the current state of radiocaesium in the Scottish soils and to compare these data with data from earlier studies, however, it was difficult to make any implications from this study due to variations in sampling techniques. Another aim was to study the transfer of 137Cs from soil to plant. Caesium resembles potassium and is readily fixed to clay minerals in the soil and weakly bound to organic matter. Plants have a difficulty in discriminating between the two elements, hence the uptake of caesium can be considerable. This study has, in accordance with other similar studies, shown that the transfer of radiocaesium to heather (Calluna vulgaris) is significantly higher than the transfer to different grass species. Concerning the movement of caesium in the soils no significant difference could be found between the two organic soils. Their migration depths were 8.2 and 8.8 cm and their migration rates were 0.36 and 0.39 cm y-1 for Knockandy Hill and Rora Moss, respectively

Barnperpektivet vid åldersbedömningar

The purpose of my essay is to examinate if Sweden fulfills its obligations towards children in age assessments of asylum seekers in their teens. To do this, I have applied the right dogmatic method and used a inter-critical perspective. As material I chosed laws, legislative history, recommendations and positions of authorities, international conventions and doctrine. The delimitations of the essay are made after the purpose and issues. I have chosen to only write about foreigners from countries outside Scandinavia and the EES-area. In the swedish legal system refugees, persons eligible for subsidiary protection and persons otherwise in need of protection have the right to residence permit. Residence permit can also be granted for a asylum seeker with exceptionally distressing circumstances. According to the 2 chapter 1§ in the swedish Aliens Act (2005:716) a foreigner who comes to Sweden has to prove its identity by passport. When it comes to asylum seekers the pass claim can rarely be fulfilled. The seeker then has to try to clarify its identity otherwise. According to the principle of free production of evidence in 35 chapter 1§ Code of Judicial Procedure (1942:740) the asylum seeker can refer to optional documents and records. In accordance with the principle benefit of doubts the seeker doesn’t havet o make its identity clarified, it is enough if the identity is probable. In asylum cases children have the same standard of proof as adults. Problems can arise when the asylum seeker is in the late teens and there are doubts about if he or she is over 18 years old or not. It is important to examinate the age of the seeker to find out how the aliens case should be handled with the benefit of being a child in the swedish asylum procedure. The Swedish Migration Board is the first instance in the procedure of asylum cases. Therefore it is the Swedish Migration Board that estimate the age of the asylum seeker. The procedure starts with exploratory talks. Supported by the Asylum Procedure directive of the EU medical age assessments are being used. A medical age assessment includes x-ray of teeth and the skeleton in the asylum seekers hand. In every decision concerning children the principle of the best interests of the child should be a primary consideration. The principle has been expressed in the both national and international legislation, and also in the EU. The term does not, on the other hand, have any established definition. The respect of the human dignity and integrity of the child are however important points in the principle. Sweden has been criticized from diffenrent directions when it comes to the principle of the best interests of the child in asylum procedures and age assessments. The critics are mostly about the effect of the principle of the best interests of the child in practice. That the age assessments are not in compliance with the rule of law is also something that Sweden has been criticized about.Syftet med min uppsats är att utreda huruvida Sverige uppfyller sina olika förpliktelser rörande barnperspektivet vid åldersbedömningar av ensamkommande asylsökande i övre tonåren. För att göra detta har jag valt att tillämpa en rättsdogmatisk metod och ett internkritiskt perspektiv. Som material valde jag lagtext, förarbeten, myndigheters rekommendationer och ställningstaganden, internationella konventioner samt doktrin. Uppsatsens avgränsningar har jag gjort i riktlinje med syftet och frågeställningen. Jag har även valt att hålla mig till utlänningar som är medborgare i länder utanför Norden och EES-området. I svensk rätt har flyktingar, alternativt skyddsbehövande och övrigt skyddsbehövande rätt till uppehållstillstånd till följd av asyl. Uppehållstillstånd kan även beviljas en sökande när det föreligger synnerligen ömmande omständigheter. För att få resa in i Sverige krävs att en utlänning kan styrka sin identitet med ett pass enligt 2 kap 1 § utlänningslagen (2005:716). När det gäller utlänningar som söker asyl kan passkravet sällan uppfyllas. Den sökande måste då istället försöka klargöra sin identitet på annat sätt. Enligt principen om fri bevisföring som härleds från 35 kap 1 § rättegångsbalken (1942:740) får den sökande åberopa valfria handlingar och uppgifter. I enlighet med bevislättnadsregeln benefit of doubts måste inte den sökande helt klargöra sin identitet utan identiteten ska anses vara sannolik. Barn har dock samma beviskrav som vuxna i asylärenden. Problem kan uppstå när den asylsökande är i övre tonåren och det råder tveksamheter huruvida han eller hon är över 18 år eller inte. Att utreda åldern är viktigt för att ta reda på hur den sökandes ärende ska hanteras i förhållande till den förmånlighet som barn har i svensk asylprocess. Migrationsverket är första instans i handläggningen av asylärenden. Således är det även Migrationsverket som ska bedöma den asylsökandes ålder. Processen inleds med orienterande samtal. Medicinsk åldersbedömning används även med stöd av EU:s asylprocedurdirektiv. Vid en sådan bedömning röntgas handskelettet och tänderna på den sökande. Vid alla beslut som rör barn ska principen om barnets bästa sättas i främsta rummet. Principen kommer till uttryck i både nationell, EU-rättslig och internationell rätt. En klar definition av begreppet saknas. Respekten för barnets människovärde och integritet är dock en viktig utgångspunkt. Sverige har kritiserats från olika håll när det gäller barnperspektivet i asylprocessen och åldersbedömningar. Den kritik som getts handlar främst om effekten av barnets bästa i praktiken samt att åldersbedömningar inte görs på ett rättssäkert sätt med ett tillfredsställande beslutsunderlag

Replacing neocortical neurons after stroke

No abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56007/1/21088_ftp.pd

Comparative Analysis of the Frequency and Distribution of Stem and Progenitor Cells in the Adult Mouse Brain

cells (NSCs) and progenitor cells, but it cannot discriminate between these two populations. Given two assays have purported to overcome this shortfall, we performed a comparative analysis of the distribution and frequency of NSCs and progenitor cells detected in 400 m coronal segments along the ventricular neuraxis of the adult mouse brain using the neurosphere assay, the neural colony forming cell assay (N-CFCA), and label-retaining cell (LRC) approach. We observed a large variation in the number of progenitor/stem cells detected in serial sections along the neuraxis, with the number of neurosphereforming cells detected in individual 400 m sections varying from a minimum of eight to a maximum of 891 depending upon the rostral-caudal coordinate assayed. Moreover, the greatest variability occurred in the rostral portion of the lateral ventricles, thereby explaining the large variation in neurosphere frequency previously reported. Whereas the overall number of neurospheres (3730 276) or colonies (4275 124) we detected along the neuraxis did not differ significantly, LRC numbers were significantly reduced (1186 188, 7 month chase) in comparison to both total colonies and neurospheres. Moreover, approximately two orders of magnitude fewer NSC-derived colonies (50 10) were detected using the N-CFCA as compared to LRCs. Given only 5% of the LRCs are cycling (BrdU/Ki-67) or competent to divide (BrdU/Mcm-2), and proliferate upon transfer to culture, it is unclear whether this technique selectively detects endogenous NSCs. Overall, caution should be taken with the interpretation and employment of all these techniques

Blockade of microglial KATP-channel abrogates suppression of inflammatory-mediated inhibition of neural precursor cells

Microglia positively affect neural progenitor cell physiology through the release of inflammatory mediators or trophic factors. We demonstrated previously that reactive microglia foster KATP-channel expression and that blocking this channel using glibenclamide administration enhances striatal neurogenesis after stroke. In this study, we investigated whether the microglial KATP-channel directly influences the activation of neural precursor cells (NPCs) from the subventricular zone using transgenic Csf1r-GFP mice. In vitro exposure of NPCs to lipopolysaccharide and interferon-gamma resulted in a significant decrease in precursor cell number. The complete removal of microglia from the culture or exposure to enriched microglia culture also decreased the precursor cell number. The addition of glibenclamide rescued the negative effects of enriched microglia on neurosphere formation and promoted a ~20% improvement in precursor cell number. Similar results were found using microglial-conditioned media from isolated microglia. Using primary mixed glial and pure microglial cultures, glibenclamide specifically targeted reactive microglia to restore neurogenesis and increased the microglial production of the chemokine monocyte chemoattractant protein-1 (MCP-1). These findings provide the first direct evidence that the microglial KATP-channel is a regulator of the proliferation of NPCs under inflammatory conditions

The late response of rat subependymal zone stem and progenitor cells to stroke is restricted to directly affected areas of their niche

AbstractIschaemia leads to increased proliferation of progenitors in the subependymal zone (SEZ) neurogenic niche of the adult brain and to generation and migration of newborn neurons. Here we investigated the spatiotemporal characteristics of the mitotic activity of adult neural stem and progenitor cells in the SEZ during the sub-acute and chronic post-ischaemic phases. Ischaemia was induced by performing a 1h unilateral middle cerebral artery occlusion (MCAO) and tissue was collected 4/5weeks and 1year after the insult. Neural stem cells (NSCs) responded differently from their downstream progenitors to MCAO, with NSCs being activated only transiently whilst progenitors remain activated even at 1year post-injury. Importantly, mitotic activation was observed only in the affected areas of the niche and specifically in the dorsal half of the SEZ. Analysis of the topography of mitoses, in relation to the anatomy of the lesion and to the position of ependymal cells and blood vessels, suggested an interplay between lesion-derived recruiting signals and the local signals that normally control proliferation in the chronic post-ischaemic phase

An extended window of opportunity for G-CSF treatment in cerebral ischemia

BACKGROUND: Granulocyte-colony stimulating factor (G-CSF) is known as a powerful regulator of white blood cell proliferation and differentiation in mammals. We, and others, have shown that G-CSF is effective in treating cerebral ischemia in rodents, both relating to infarct size as well as functional recovery. G-CSF and its receptor are expressed by neurons, and G-CSF regulates apoptosis and neurogenesis, providing a rational basis for its beneficial short- and long-term actions in ischemia. In addition, G-CSF may contribute to re-endothelialisation and arteriogenesis in the vasculature of the ischemic penumbra. In addition to these trophic effects, G-CSF is a potent neuroprotective factor reliably reducing infarct size in different stroke models. RESULTS: Here, we have further delayed treatment and studied effects of G-CSF on infarct volume in the middle cerebral artery occlusion (MCAO) model and functional outcome in the cortical photothrombotic model. In the MCAO model, we applied a single dose of 60 μg/kg bodyweight G-CSF in rats 4 h after onset of ischemia. Infarct volume was determined 24 h after onset of ischemia. In the rat photothrombotic model, we applied 10 μg/kg bodyweight G-CSF daily for a period of 10 days starting either 24 or 72 h after induction of ischemia. G-CSF both decreased acute infarct volume in the MCAO model, and improved recovery in the photothrombotic model at delayed timepoints. CONCLUSION: These data further strengthen G-CSF's profile as a unique candidate stroke drug, and provide an experimental basis for application of G-CSF in the post-stroke recovery phase

Age-Related Changes in Astrocytic and Ependymal Cells of the Subventricular Zone

Neurogenesis persists in the adult subventricular zone (SVZ) of the mammalian brain. During aging, the SVZ neurogenic capacity undergoes a progressive decline, which is attributed to a decrease in the population of neural stem cells (NSCs). However, the behavior of the NSCs that remain in the aged brain is not fully understood. Here we performed a comparative ultrastructural study of the SVZ niche of 2-month-old and 24-month-old male C57BL/6 mice, focusing on the NSC population. Using thymidine-labeling, we showed that residual NSCs in the aged SVZ divide less frequently than those in young mice. We also provided evidence that ependymal cells are not newly generated during senescence, as others studies suggest. Remarkably, both astrocytes and ependymal cells accumulated a high number of intermediate filaments and dense bodies during aging, resembling reactive cells. A better understanding of the changes occurring in the neurogenic niche during aging will allow us to develop new strategies for fighting neurological disorders linked to senescence

Spinal Cord Injury Reveals Multilineage Differentiation of Ependymal Cells

Spinal cord injury often results in permanent functional impairment. Neural stem cells present in the adult spinal cord can be expanded in vitro and improve recovery when transplanted to the injured spinal cord, demonstrating the presence of cells that can promote regeneration but that normally fail to do so efficiently. Using genetic fate mapping, we show that close to all in vitro neural stem cell potential in the adult spinal cord resides within the population of ependymal cells lining the central canal. These cells are recruited by spinal cord injury and produce not only scar-forming glial cells, but also, to a lesser degree, oligodendrocytes. Modulating the fate of ependymal progeny after spinal cord injury may offer an alternative to cell transplantation for cell replacement therapies in spinal cord injury

Transcranial Low-Level Laser Therapy Improves Neurological Performance in Traumatic Brain Injury in Mice: Effect of Treatment Repetition Regimen

Low-level laser (light) therapy (LLLT) has been clinically applied around the world for a spectrum of disorders requiring healing, regeneration and prevention of tissue death. One area that is attracting growing interest in this scope is the use of transcranial LLLT to treat stroke and traumatic brain injury (TBI). We developed a mouse model of severe TBI induced by controlled cortical impact and explored the effect of different treatment schedules. Adult male BALB/c mice were divided into 3 broad groups (a) sham-TBI sham-treatment, (b) real-TBI sham-treatment, and (c) real-TBI active-treatment. Mice received active-treatment (transcranial LLLT by continuous wave 810 nm laser, 25 mW/cm[superscript 2], 18 J/cm[superscript 2], spot diameter 1 cm) while sham-treatment was immobilization only, delivered either as a single treatment at 4 hours post TBI, as 3 daily treatments commencing at 4 hours post TBI or as 14 daily treatments. Mice were sacrificed at 0, 4, 7, 14 and 28 days post-TBI for histology or histomorphometry, and injected with bromodeoxyuridine (BrdU) at days 21–27 to allow identification of proliferating cells. Mice with severe TBI treated with 1-laser Tx (and to a greater extent 3-laser Tx) had significant improvements in neurological severity score (NSS), and wire-grip and motion test (WGMT). However 14-laser Tx provided no benefit over TBI-sham control. Mice receiving 1- and 3-laser Tx had smaller lesion size at 28-days (although the size increased over 4 weeks in all TBI-groups) and less Fluoro-Jade staining for degenerating neurons (at 14 days) than in TBI control and 14-laser Tx groups. There were more BrdU-positive cells in the lesion in 1- and 3-laser groups suggesting LLLT may increase neurogenesis. Transcranial NIR laser may provide benefit in cases of acute TBI provided the optimum treatment regimen is employed.National Institutes of Health (U.S.) (Grant R01AI050875)Center for Integration of Medicine and Innovative Technology (DAMD17-02-2-0006)United States. Dept. of Defense. Congressionally Directed Medical Research Programs (W81XWH-09-1-0514)United States. Air Force Office of Scientific Research. Military Photomedicine Program (FA9550-11-1-0331