RDF-based P2P networks have a number of advantages compared to simpler P2P networks such as Napster, Gnutella or to approaches based on distributed indices on binary keys such as CAN and CHORD. RDF-based P2P networks allow complex and extendable descriptions of resources instead of fixed and limited ones, and they provide complex query facilities against these metadata instead of simple keyword-based searches. In this paper we will discuss RDF-based P2P networks like Edutella as a specific example of a new type of P2P networks - schema-based P2P networks - and describe the use of super-peer based topologies for these networks. Super-peer based networks can provide better scalability than broadcast based networks, and provide support for inhomogeneous schema-based networks, with different metadata schemas and ontologies (crucial for the Semantic Web). Based on (dynamic) metadata routing indices, stated in RDF, the superpeer network supports sophisticated routing and distribution strategies, as well as preparing the ground for advanced mediation and clustering functionalities.
M. Höistad, H. Heinsen, B. Wicinski, C. Schmitz and P. R. Hof (2013) Neuropathology and Applied Neurobiology 39, 348–361 Stereological assessment of the dorsal anterior cingulate cortex in schizophrenia: absence of changes in neuronal and glial densities Aims: The prefrontal and anterior cingulate cortices are implicated in schizophrenia, and many studies have assessed volume, cortical thickness, and neuronal densities or numbers in these regions. Available data, however, are rather conflicting and no clear cortical alteration pattern has been established. Changes in oligodendrocytes and white matter have been observed in schizophrenia, introducing a hypothesis about a myelin deficit as a key event in disease development. Methods: We investigated the dorsal anterior cingulate cortex (dACC) in 13 men with schizophrenia and 13 age‐ and gender‐matched controls. We assessed stereologically the dACC volume, neuronal and glial densities, total neurone and glial numbers, and glia/neurone index (GNI) in both layers II–III and V–VI. Results: We observed no differences in neuronal or glial densities. No changes were observed in dACC cortical volume, total neurone numbers, and total glial numbers in schizophrenia. This contrasts with previous findings and suggests that the dACC may not undergo as severe changes in schizophrenia as is generally believed. However, we observed higher glial densities in layers V–VI than in layers II–III in both controls and patients with schizophrenia, pointing to possible layer‐specific effects on oligodendrocyte distribution during development. Conclusions: Using rigorous stereological methods, we demonstrate a seemingly normal cortical organization in an important neocortical area for schizophrenia, emphasizing the importance of such morphometric approaches in quantitative neuropathology. We discuss the significance of subregion‐ and layer‐specific alterations in the development of schizophrenia, and the discrepancies between post mortem histopathological studies and in vivo brain imaging findings in patients.
Introduction: In the fetus, the right ventricle (RV) is the dominant ventricle, contributing more than 50% to the combined cardiac output. RV dysfunction results in severe fetal cardiac failure with sometimes unpredictable postnatal outcome.
Acute aortic dissection is a rare disease, but if it occurs rapid diagnosis and therapy are needed. It is usually seen in elderly patients with long-term persistent arterial hypertension. In younger patients, it is mainly caused by congenital connective tissue disorders, such as Marfan syndrome, or by trauma. We present here a 34-year-old male patient with an acute type A aortic dissection. This patient was a professional parachutist and had carried out a large number of parachute jumps during his lifetime. He was admitted to the emergency department with acute chest pain. The symptoms were not related in time to a parachute jump. During a computed tomography scan, an aortic dissection was diagnosed. The patient was immediately referred to the operating room, and the ascending aorta was replaced by a conduit. After a regular postoperative course, the patient was discharged and recovered completely. Although acute aortic dissection is rare in young patients, it has to be considered in cases of acute chest pain. An immediate diagnosis and adequate therapy are essential to offer the patient a good clinical outcome and long-term survival.
ABSTRACT Background Current management options for partial tendon tears may not offer future potential to heal tissue and improve clinical results. This study tested the hypothesis that treatment of a partial rabbit common calcaneus tendon (CCT) defect with uncultured, autologous, adipose derived regenerative cells (UA-ADRCs) enables regenerative healing without scar formation, as recently observed in a biopsy of a human supraspinatus tendon. Methods A full-thickness hole (diameter, 3 mm) was punched into the midsubstance of the right gastrocnemius tendon (GT; which is a part of the CCT) of adult, female New Zealand white rabbits. Immediately thereafter the rabbits were treated by application of an averaged 28.3×10 6 UA-ADRCs in 0.5 ml lactated Ringer’s solution (RLS) into the GT defect and surrounding tendon tissue, or underwent sham treatment. Rabbits were sacrificed either four weeks (W4) or twelve weeks (W12) post-treatment, and the CCTs were investigated using histology, immunohistochemistry and non-destructive biomechanical testing. Results Newly formed connective tissue was consistent with the formation of new tendon tissue after treatment with UA-ADRCs, and with the formation of scar tissue after sham treatment, at both W4 and W12 post-treatment. Biomechanical testing demonstrated a significantly higher mean percent relaxation after treatment with UA-ADRCs than after sham treatment (p < 0.05), and significant, negative correlations between the peak stress as well as the equilibrium stress and the cross-sectional area of the CCT (p < 0.05) after treatment with UA-ADRCs but not after sham treatment. Conclusions Management of partial tendon tears with UA-ADRCs has the potential to be truly “structure-modifying”.
The aging process in the hippocampus is associated with aberrant epigenetic marks, such as DNA methylation and histone tail alterations. Recent evidence suggests that caloric restriction (CR) can potentially delay the aging process, while upregulation of antioxidants may also have a beneficial effect in this respect. We have recently observed that CR attenuates age-related changes in the levels of the epigenetic molecules DNA methyltransferase 3a, 5-methylcytidine (5- mC) and 5-hydroxymethylcytosine in the mouse hippocampus while overexpression of the antioxidant Cu/Zn superoxide dismutase 1 (SOD1) does not. However, the impact of aging on the levels of histone-modifying enzymes such as histone deacetylase 2 (HDAC2) in the hippocampus has not been studied in much detail. Here, we investigated immunoreactivity (IR) of HDAC2 in three subregions of the hippocampus (dentate gyrus, CA3 and CA1-2) of mice taken from large cohorts of aging wild-type and transgenic mice overexpressing normal human SOD1, which were kept under normal diet or CR from weaning onwards. Independent from the genotype, aging (between 12 and 24 months) increased levels of HDAC2 IR in the hippocampus. Moreover, CR prevented this age-related increase, particularly in the CA3 and CA1-2 subregions, while SOD1 overexpression did not. Quantitative image analyses showed that HDAC2 IR correlated positively with 5-mC IR while these markers were shown to colocalize in the nucleus of hippocampal cells. Together with recent literature reports, these findings suggest that altered levels of epigenetic regulatory proteins including HDAC2 regulate age-related changes in the mouse hippocampus and that CR may prevent these age-related changes.
