ABSTRACT
OBJECT: DuraGen (Integra Neurosciences, Plainsboro, NJ, USA) is an avascular collagen matrix used for dural closure. Although, numerous animal models have been studied, histological transformation of DuraGen in humans has not been reported. MATERIAL AND METHOD: We analyzed a sample of scarred DuraGen used in a craniectomy patient at time of delayed cranioplasty. CONCLUSION: Histological analysis revealed evidence for both fibroblast infiltration and neovascularization of the DuraGen.
Subject(s)
Biocompatible Materials/therapeutic use , Collagen/therapeutic use , Dura Mater/surgery , Adolescent , Cerebral Hemorrhage/etiology , Cerebral Hemorrhage/surgery , Decompression, Surgical , Humans , Male , Precursor Cell Lymphoblastic Leukemia-Lymphoma/complicationsABSTRACT
Angiostatin is a cleavage product of plasminogen that has anti-angiogenic properties. We investigated whether the effects of angiostatin on endothelial cells are mediated by ceramide, a lipid implicated in endothelial cell signaling. Our results demonstrate that angiostatin produces a transient increase in ceramide that correlates with actin stress fiber reorganization, detachment and death. DNA array expression analysis performed on ceramide-treated human endothelial cells demonstrated induction of certain genes involved in cytoskeleton organization. Specifically, we report that treatment with angiostatin or ceramide results in the activation of RhoA, an important effector of cytoskeletal structure. We also show that treatment of endothelial cells with the antioxidant N-acetylcysteine abrogates morphological changes and cytotoxic effects of treatment with angiostatin or ceramide. These findings support a model in which angiostatin induces a transient rise in ceramide, RhoA activation and free radical production.
Subject(s)
Endothelium, Vascular/cytology , Peptide Fragments/physiology , Plasminogen/physiology , Sphingosine/metabolism , rhoA GTP-Binding Protein/metabolism , Angiostatins , Cell Membrane/metabolism , Cells, Cultured , Cytoskeleton/metabolism , Dose-Response Relationship, Drug , Homeodomain Proteins/metabolism , Humans , Immunoblotting , Kinetics , LIM-Homeodomain Proteins , Microscopy, Phase-Contrast , Nerve Tissue Proteins/metabolism , Oligonucleotide Array Sequence Analysis , Protein Transport , Signal Transduction , Sphingosine/analogs & derivatives , Time Factors , Transcription Factors , Umbilical Veins/cytologyABSTRACT
The availability of implantable subdural electrode arrays has made systematic studies of electrocorticographic (ECoG) coherence possible. Studies of coherence patterns recorded directly from human cortex are reviewed along with the presentation of original human clinical data, which reveal reliable and characteristic patterns of coherence. A data-driven technique for discriminating between reliable and unreliable coherence and phase values is described and used to reveal the relationship between coherence and cortical anatomy, such as in the region of the central sulcus, where low phase coherence declines and high phase-shifted coherence increases. Analysis of coherence magnitude and phase makes it possible to determine which signals likely arise from the cortical surface, and which arise from the depths of a sulcus. Alterations in coherence patterns caused by tumors or epilepsy are described and may be used to identify normal and pathological functional relationships between distant cortical areas. Some electrophysiologic/pathologic correlations indicate at least two types of epileptic abnormality, implying a sequence in breakdown of epileptic tissue. The relationship between coherence patterns and behavior and cognition is introduced and compared to similar studies of single-unit binding in animals.
