How Necessary is the Vasculature in the Life of Neural Stem and Progenitor Cells? Evidence from Evolution, Development and the Adult Nervous System.

Augmenting evidence suggests that such is the functional dependance of neural stem cells (NSCs) on the vasculature that they normally reside in “perivascular niches”. Two examples are the “neurovascular” and the “oligovascular” niches of the adult brain, which comprise specialized microenvironments where NSCs or oligodendrocyte progenitor cells survive and remain mitotically active in close proximity to blood vessels (BVs). The often observed co-ordination of angiogenesis and neurogenesis led to these processes being described as “coupled”. Here, we adopt an evo-devo approach to argue that some stages in the life of a NSC, such as specification and commitment, are independent of the vasculature, while stages such as proliferation and migration are largely dependent on BVs. We also explore available evidence on the possible involvement of the vasculature in other phenomena such as the diversification of NSCs during evolution and we provide original data on the senescence of NSCs in the subependymal zone stem cell niche. Finally, we will comment on the other side of the story; that is, on how much the vasculature is dependent on NSCs and their progeny

Subependymal Zone-Derived Oligodendroblasts Respond to Focal Demyelination but Fail to Generate Myelin in Young and Aged Mice

wo populations of oligodendrogenic progenitors co-exist within the corpus callosum (CC) of the adult mouse. Local, parenchymal oligodendrocyte progenitor cells (pOPCs) and progenitors generated in the subependymal zone (SEZ) cytogenic niche. pOPCs are committed perinatally and retain their numbers through self-renewing divisions, while SEZ-derived cells are relatively “young,” being constantly born from neural stem cells. We compared the behavior of these populations, labeling SEZ-derived cells using hGFAP:Cre$^{Ert2}$ mice, within the homeostatic and regenerating CC of the young-adult and aging brain. We found that SEZ-derived oligodendroglial progenitors have limited self-renewing potential and are therefore not bona fide OPCs but rather “oligodendroblasts” more similar to the neuroblasts of the neurogenic output of the SEZ. In the aged CC their mitotic activity is much reduced, although they still act as a “fast-response element” to focal demyelination. In contrast to pOPCs, they fail to generate mature myelinating oligodendrocytes at all ages studied.This work was supported by a grant from the Biotechnology and Biological Sciences Research Council (UK) ( BB/I013210/1 ) to R.F. and I.K

Performance evaluation of the FPRRA framework for GEO satellites in the absence of accurate multimedia traffic prediction

In recent work [1] we have introduced and evaluated a fair and dynamic joint Call Admission Control (CAC) and Multiple Access Control (MAC) framework, for Geostationary (GEO) Satellite Systems, named Fair Predictive Resource Reservation Access (FPRRA). The framework was based on accurate videoconference and data traffic prediction, made decisions after taking into account the provider revenue, and was shown to be highly efficient. However, the accurate modeling of multimedia traffic is not always possible, especially in the case of video (i.e., not videoconference) traffic. In this paper we evaluate the performance of FPRRA in the absence of accurate video traffic modeling and we discuss the efficiency of the scheme in comparison to other efficient schemes from the literature

The rationale and design of a Mediterranean diet accompanied by time restricted feeding to optimise the management of type 2 diabetes: the MedDietFast randomised controlled trial

Background and Aims Substantial scientific evidence supports the effectiveness of a Mediterranean diet (MedDiet) in managing type 2 diabetes mellitus (T2DM). Potential benefits of time restricted feeding (TRF) in T2DM are unknown. The MedDietFast trial aims to investigate the efficacy of a MedDiet with or without TRF compared to standard care diet in managing T2DM. Methods and Results 120 adults aged 20 -75 with a body mass index (BMI) of 20-35 kg/m2 and T2DM will be randomised in a 3-arm parallel design to follow an ad libitum MedDiet with or without 12-hours TRF or the standard Australian Dietary Guidelines (ADG) for 24 weeks. All groups will receive dietary counselling fortnightly for 12 weeks and monthly thereafter. The primary outcome is changes in HbA1c from baseline to 12 and 24 weeks. Secondary outcomes include fasting blood glucose, insulin, blood lipids, weight loss, insulin resistance index (HOMA), Glucagon-like peptide 1 (GLP-1) and high-sensitivity C- reactive protein (hs-CRP). Data on medical history, anthropometry, wellbeing, MedDiet adherence and satiety will be measured at a private clinic via self-report questionnaires at baseline, 6, 12 and 24 weeks. Additionally, specimens (blood, urine and stool) will be collected at all time points for future omics analysis. Conclusion The MedDietFast trial will examine the feasibility and effectiveness of a MedDiet with/without TRF in T2DM patients. Potential synergistic effects of a MedDiet with TRF will be evaluated. Future studies will generate microbiomic and metabolomic data for translation of findings into simple and effective management plans for T2DM patients

User satisfaction-based resource allocation for GEO satellites

Summarization: In recent work we have introduced and evaluated a fair and dynamic joint Call Admission Control (CAC) and Multiple Access Control (MAC) framework, for Geostationary Orbit (GEO) Satellite Systems, named Fair Predictive Resource Reservation Access (FPRRA). The framework was based on accurate videoconference and data traffic prediction, made decisions after taking into account the provider's revenue, and was shown to be highly efficient. In this paper we enhance FPRRA by talking into account the users' satisfaction for making scheduling decisions and we focus on its evaluation in the absence of accurate MPEG-4 and H.264 video traffic modeling. In addition, we discuss the efficiency of our proposed scheme in comparison to other efficient schemes from the literature.Παρουσιάστηκε στο: IEEE International Symposium on a World of Wireless, Mobile and Multimedia Network

User satisfaction-based resource allocation for GEO satellites

In recent work we have introduced and evaluated a fair and dynamic joint Call Admission Control (CAC) and Multiple Access Control (MAC) framework, for Geostationary Orbit (GEO) Satellite Systems, named Fair Predictive Resource Reservation Access (FPRRA). The framework was based on accurate videoconference and data traffic prediction, made decisions after taking into account the provider's revenue, and was shown to be highly efficient. In this paper we enhance FPRRA by talking into account the users' satisfaction for making scheduling decisions and we focus on its evaluation in the absence of accurate MPEG-4 and H.264 video traffic modeling. In addition, we discuss the efficiency of our proposed scheme in comparison to other efficient schemes from the literature

Initial experience with renal denervation for the treatment of resistant hypertension - The utility of novel anesthetics and metaiodobenzylguanidine scintigraphy (MIBG)

Background: The Symplicity-HTN 3 trial failed to show significant difference in blood pressure (BP) lowering between patients undergoing catheter-based renal denervation (RDN) and the sham-procedure arm of the study. However, there is still optimism about the role of RDN in the treatment of resistant hypertension, because identification of patients with increased sympathetic activity thus being good RDN responders, improvements in the RDN procedure and new technology RDN catheters are all expected to lead to better RDN results. We present our initial experience with RDN for the treatment of resistant hypertension, and the utility of novel anesthetics and cardiac123I-metaiodobenzylguanidine scintigraphy (123I-MIBG). Methods and Results: Seven patients with resistant hypertension underwent RDN and were followed up for 6 months. MIBG was performed before RDN, in order to estimate sympathetic activity and predict the response to RDN. All patients were sedated with dexmedetomidine and remifentanil during RDN. All patients tolerated the procedure well, were hemodynamically stable and their peri-procedural pain was effectively controlled. A median of 7.6 ± 2.1 and 6 ± 1.4 ablations were delivered in the right and left renal artery respectively, making an average of 6.8 burns per artery. No peri-procedural or late complications - adverse events (local or systematic) occurred. At 6 months, mean reduction in office BP was -26.0/-16.3 mmHg (p=0.004/p=0.02), while mean reduction in ambulatory BP was -12.3/-9.2 mmHg (p=0.118/p=0.045). One patient (14.3%) was a non-responder. None of the cardiac123I-MIBG imaging indexes (early and late heart-to-mediastinum (H/M) count density ratio, washout rate (WR) of the tracer from the myocardium) were different between responders and non-responders. Conclusion: Patients with resistant hypertension who underwent RDN in our department had a significant reduction in BP 6 months after the intervention.123I-MIBG was not useful in predicting RDN response. Dexmedetomidine and remifentanil provided sufficient patient comfort during the procedure, allowing an adequate number of ablations per renal artery to be performed, and this could probably lead to improved RDN results. © Ziakas et al