Human Neural Stem Cells Over-Expressing VEGF Provide Neuroprotection, Angiogenesis and Functional Recovery in Mouse Stroke Model

BACKGROUND: Intracerebral hemorrhage (ICH) is a lethal stroke type. As mortality approaches 50%, and current medical therapy against ICH shows only limited effectiveness, an alternative approach is required, such as stem cell-based cell therapy. Previously we have shown that intravenously transplanted human neural stem cells (NSCs) selectively migrate to the brain and induce behavioral recovery in rat ICH model, and that combined administration of NSCs and vascular endothelial growth factor (VEGF) results in improved structural and functional outcome from cerebral ischemia. METHODS AND FINDINGS: We postulated that human NSCs overexpressing VEGF transplanted into cerebral cortex overlying ICH lesion could provide improved survival of grafted NSCs, increased angiogenesis and behavioral recovery in mouse ICH model. ICH was induced in adult mice by unilateral injection of bacterial collagenase into striatum. HB1.F3.VEGF human NSC line produced an amount of VEGF four times higher than parental F3 cell line in vitro, and induced behavioral improvement and 2–3 fold increase in cell survival at two weeks and eight weeks post-transplantation. CONCLUSIONS: Brain transplantation of F3 human NSCs over-expressing VEGF near ICH lesion sites provided differentiation and survival of grafted human NSCs and renewed angiogenesis of host brain and functional recovery of ICH animals. These results suggest a possible application of the human neural stem cell line, which is genetically modified to over-express VEGF, as a therapeutic agent for ICH-stroke

Hair analysis for the detection of drug use – is there potential for evasion?

Background: Hair analysis for illicit substances is widely used to detect chronic drug consumption or abstention from drugs. Testees are increasingly seeking ways to avoid detection by using a variety of untested adulterant products (e.g. shampoos, cleansers) widely sold online. This study aims to investigate adulteration of hair samples and to assess effectiveness of such methods. Methods: The literature on hair test evasion was searched for on PubMed/MEDLINE, Psycinfo, and Google Scholar. Given the sparse nature of peer-reviewed data on this subject, results were integrated with a qualitative assessment of online sources, including user-orientated information/commercial websites, drug fora and ‘chat rooms’. Over four million web sources were identified in a Google search by using ‘beat hair drug test’ and the first 86 were monitored on regular basis and considered for further analysis. Results: Attempts to influence hair test results are widespread. Various ‘shampoos’, ‘cleansers’ among other products, were found for sale, which claim to remove analytes. Often advertised with aggressive marketing strategies, which include discounts, testimonials and unsupported claims of efficacy. However, these products may pose serious health hazards and are also potentially toxic. In addition, many anecdotal reports suggest that Novel Psychoactive Substances (NPS) are also consumed as an evasion technique, as these are not easily detectable via standard drug test. Recent changes on NPS legislations such as New Psychoactive Bill in the UK might further challenge the testing process. Conclusion: Further research is needed by way of chemical analysis and trial of the adulterant products sold online and their effects as well as the development of more sophisticated hair testing techniques

Estudi Anual Xarxes Socials 2017

- Análisi de l'empresa de serveis - Diagnòstic de les necessitats de l'empresa - Pla de Marketing - Conclusionsit is a study that reflects statistical data of the use of social networks in Spain.Es un estudio donde se reflejan datos estadisticos de interés sobre el uso de las redes sociales en España.Es un estudi on es reflexen dades estadisticos d'interés sobre l'uso de les xarxes sociales a Espanya

Estudi Anual Xarxes Socials 2017

- Análisi de l'empresa de serveis - Diagnòstic de les necessitats de l'empresa - Pla de Marketing - Conclusionsit is a study that reflects statistical data of the use of social networks in Spain.Es un estudio donde se reflejan datos estadisticos de interés sobre el uso de las redes sociales en España.Es un estudi on es reflexen dades estadisticos d'interés sobre l'uso de les xarxes sociales a Espanya

Estudi Anual Xarxes Socials 2017

- Análisi de l'empresa de serveis - Diagnòstic de les necessitats de l'empresa - Pla de Marketing - Conclusionsit is a study that reflects statistical data of the use of social networks in Spain.Es un estudio donde se reflejan datos estadisticos de interés sobre el uso de las redes sociales en España.Es un estudi on es reflexen dades estadisticos d'interés sobre l'uso de les xarxes sociales a Espanya

Focal cerebral ischemia causes two temporal waves of Akt activation

We studied whether pro-survival Akt was activated after transient focal cerebral ischemia and whether it inhibited pro-apoptotic Bad. Phosphorylation of Akt (serine-473) was enhanced in cortex after 1-hour ischemia, and also after 1 h and 6 h of reperfusion, but it returned back to that in controls by 24 h. After this first wave of Akt activation, a second increase was observed between 4 and 7 days. In striatum, only the late Akt activation was seen. In contrast to Akt, no Bad phosphorylation (serine-136) was detected after ischemia. Therefore, injury spontaneously activated Akt, but this did not suppress Bad signalling. It is proposed that further pharmacological activation of Akt shortly after ischemia might promote cell survival, whereas Akt activation at longer time points is involved with glial reactivity. © 2001 Lippincott Williams & Wilkins.Peer Reviewe

Transforming growth factor-α attenuates N-methyl-D-aspartic acid toxicity in cortical cultures by preventing protein synthesis inhibition through an Erk1/2-dependent mechanism

Transforming growth factor-α (TGF-α), a ligand of the epidermal growth factor receptor, reduces the infarct size after focal cerebral ischemia in rat, but the molecular basis underlying the protection is unknown. Excitotoxicity and global inhibition of translation are acknowledged to contribute significantly to the ischemic damage. Here we studied whether TGF-α can rescue neurons from excitotoxicity in vitro and how it affects calcium homeostasis, protein synthesis, and the associated Akt and extracellular signal-regulated kinase 1/2 (Erk1/2) intracellular signaling pathways in mixed neuron-glia cortical cultures. We found that 100 ng/ml TGF-α attenuated neuronal cell death induced by a 30-min exposure to 35 οM N-methyl-D-aspartic acid (NMDA) (as it reduced lactate dehydrogenase release, propidium iodide staining, and caspase-3 activation) and decreased the elevation of intracellular Ca2+ elicited by NMDA. TGF-α induced a prompt and sustained phosphorylation of Erk1/2 and prevented the loss of Akt-P induced by NMDA 3 h after exposure. The protective effect of TGF-α was completely prevented by PD 98059, an inhibitor of the Erk1/2 pathway. Studies of incorporation of [3H]leucine into proteins showed that NMDA decreased the rate of protein synthesis, and TGF-α attenuated this effect. TGF-α stimulated the phosphorylation of the eukaryotic initiation factor 4E (eIF4E) but did not affect eIF2α, two proteins involved in translation regulation. PD 98059 abrogated the TGF-α effect on eIF4E. Our data demonstrate that TGF-α exerts a neuroprotective action against NMDA toxicity, in which Erk1/2 activation plays a key role, and suggest that the underlying mechanisms involve recovery of translation inhibition, mediated at least in part by eIF4E phosphorylation.This work was supported by Spanish Ministry of Science and Technology (MCYT) Grants SAF 2002-01963, FIS 00/0957, and 01/1318Peer Reviewe

Early modifications in the expression of mitogen-activated protein kinase (MAPK/ERK), stress-activated kinases SAPK/JNK and p38, and their phosphorylated substrates following focal cerebral ischemia

Focal ischemia induced by middle cerebral artery occlusion (MCAO) to adult rats results in necrosis at the infarct core and activation of complex signal pathways for cell death and cell survival in the penumbra. Upstream from the cell death promoters and executioners are several kinases that, once activated by phosphorylation, may activate several transcription factor substrates involved in cell death and cell survival. In the present study we examined, by immunohistochemistry, the expression of phosphorylated (active) mitogen-activated protein kinase, extracellular signal-regulated kinase (MAPK/ERK), stress-activated protein kinase (SAPK), c-Jun N-terminal kinase (JNK) and p-38 kinase at early stages (1-4 h) following 1 h of MCAO in the rat. The expression of phosphorylation-dependent, active transcription substrates of these kinases, including cyclic AMP-responsive element-binding protein (CREB) Alk-1, ATF-2, c-Myc and c-Jun was examined at early stages following reperfusion. Increased nuclear phosphorylated SAPK/JNK (SAPK/JNK-P) and c-Jun-PSer63, and reduced CREB-P, occurred in the infarct core at 1 h following reperfusion, suggesting increased phosphorylated SAPK/JNK and c-JunSer63, together with decreased phospho-CREB associated with cell death in the infarct core. However, increased cytoplasmic expression of MAPK/ERK-P, SAPK/JNK-P, p38-P, CREB-P, Elk-1-P, c-Myc-P, ATF-2-P and c-Jun-P occurred in the region bordering the infarct core (penumbra) at 4 h following reperfusion. This indicates that different signals converge in the cytoplasm of neurons located at the borders of the infarct at 4 h following reperfusion, revealing the struggle of death promoters and life facilitators at the penumbra. Whether phosphorylated kinases and specific substrates participate in promoting cell death or survival in the penumbra probably depends on additional factors and on the interaction with other proteins.This work was supported in part by the UE contract QLG3-CT-1999-602 and FIS grants 00/0957 and 01/1557Peer Reviewe

Activation of ERK and Akt signaling in focal cerebral ischemia: Modulation by TGF-α and involvement of NMDA receptor

Cerebral ischemia activates ERK and Akt pathways. We studied whether these activations were affected by treatment with the protective growth factor transforming growth factor-α (TGF-α), and whether they were mediated through N-methyl D-aspartate (NMDA) receptors. The middle cerebral artery was occluded in rats and signaling was studied 1 h later. Noncompetitive NMDA receptor antagonist MK-801 was injected i.p. before the occlusion, whereas in other rats TGF-α was given intraventricularly before and after occlusion. Ischemia caused ERK phosphorylation in the nucleus, localized in the endothelium and neurons. Phosphorylation of ERK was prevented by TGF-α, but it was enhanced in the nucleus and cytoplasm by MK-801. Also, MK-801 but not TGF-α increased p-Akt. Results suggest that preventing ERK activation is related to the protective effect of TGF-α, whereas the protective effect of MK-801 is associated with activation of pro-survival Akt. While results support that NMDA receptor signaling precludes Akt activation, we did not find evidence to support that it underlies ischemia-induced ERK phosphorylation. This study illustrates that neuroprotection results from a fine balance between death and survival signaling pathways. © 2003 Elsevier Science (USA).This work was supported by Fondo de Investigaciones Sanitarias (Grant FIS 00/0957). B.F. has a fellowship from the University of Barcelona, and the Spanish Ministry of Education and Culture supports Dr. V.P.Peer Reviewe