1986 — 1989 |
Rosenstein, Jeffrey M |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Neural Transplant Interactions With Developing Brain @ George Washington University
Neural transplantation, increasingly, is a major tool for studying questions in neurobiology. This research project will study transplant functionality from the perspective of fluid environments; the blood vascular system and the cerebrospinal fluid (CSF). The major hypothesis contends that neural transplantation serves to permanently alter homeostasis of the brain; circulating neuroactive substances, such as protein or neurotransmitters, might gain access to normally non-accessible brain areas. The exchange of cellular elements, such as endothelium, between host and transplant may change the normal functional properties of the Blood-Brain Barrier (BBB). THe longer term objectives are to understand mechanisms in BBB development and alterations in neural transplants and how it might alter the brain's fluid environment. Lack of BBB properties should expose both host and transplant to compounds, either naturally occurring or administered, that are normally sequestered from brain tissue. One specific aim of the project is to determine if autonomic tissue transplants exist as a portal into the brain and CSF in that the passage of blood-borne proteins or neurotransmitters is facilitated at the transplant site. A further objective is to determine if transplants from the fetal CNS develop basic characteristics of a mature BBB; preliminary data for this project suggest they do not. Using several methodologies including protein and fluorescent histochemistry, gel electrophoresis, immunocytochemistry, in vivo autoradiography and 2-deoxy-D-glucose technique, this project will attempt to determine if CNS transplants retain normal or altered criteria for protein and amine permeability, cerebral microvessel characteristics, glucose utilization and certain peptide receptors. The results of these and future studies of this research program not only may elucidate aspects of BBB development but may be important for comparisons with other model systems of BBB breakdown such as head trauma, hypertension or brain tumor induction.
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1990 — 1993 |
Rosenstein, Jeffrey M |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Neural Transplants: Interactions With Developing Brain @ George Washington University
Neural transplantation is well recognized as an important experimental and clinical method for studying problems in neurobiology. The broad long-term objectives of this proposal are to determine the morphological and physiological nature of blood vascular and humoral connectivity between host and graft. Specifically, in the experimental transplantation models attempts will be made to elucidate the nature of alterations in the blood- brain barrier (BBB) and blood-CSF barrier. These models utilize both adrenal medulla and fetal CNS tissue grafts. A major hypothesis is that adrenal medulla, due to its intrinsic vascular permeability can act as a biological portal and permit blood-borne compounds to gain access into the brain and CSF of hosts where normally they would be excluded. These experiments will lay groundwork to investigate not only of whether host-graft connectivity potentially may be affected by vascular neuroactive agents but if normal, fluid homeostasis is altered. To accomplish these aims transplant-bearing rats will receive vascular injections of protein or radiolabeled neurotransmitter and histochemistry, immunohistochemistry and in vivo autoradiography will be performed to determine if both graft and host neurons have access to specific exogenous compounds. CSF content will be evaluated by immuno- affinity chromatography for immunoglobulin. In fetal CNS tissues, further studies will examine specific parameters of BBB deficiency. These include the use of a new monoclonal antibody, endothelial Brain Antigen, for BBB-competent vessels, localization of insulin receptors in brain grafts, and the appearance of certain cellular immunological responses such as the deposition of immune by products (complexes). In addition the functional metabolic and developmental states of grafted neurons will be examined by localization of Neuron Specific Enolase and receptors for growth and vascular related peptides will be examined using in vitro autoradiography. The results of these and future studies will elucidate aspects of BBB properties in neural transplants and may be important for comparisons with certain neurological states when the 888 is compromised.
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1992 |
Rosenstein, Jeffrey M |
R13Activity Code Description: To support recipient sponsored and directed international, national or regional meetings, conferences and workshops. |
Fourth International Symposium On Neural Transplantation @ George Washington University
This is an application to support the Fourth Symposium on Neural Transplantation, to be held in Washington, D.C. on July 12-16, 1992. The previous three meetings stressed many different types of grafts and phenomenological studies documenting survival, growth and function. In this fourth meeting, a number of critical aspects of applied grafting have evolved to the point of meriting a specific focus. These include (1) evaluation of transplant efficacy in animal models of neurodegenerative disease, (2) utilization of neural grafts in clinical disorders, (3) optimization of grafts using neuronotrophic factors, (4) neuroimmunology, and (5) application of recombinant DNA technology to grafting protocols, amongst others. Most importantly, however, this meeting will stress, at the basic science level, the use of implants to understand the fundamental mechanisms associated with maturation, regeneration, and regulation of connectivity in the vertebrate CNS. In addition, emphasis will be placed on modern molecular biological approaches which might allow other types of cells to substitute for fetal neuroblasts as donor material. The specific an longer term objective is to enable different neuroscience disciplines, represented by prominent individuals and those in-training, to interact together to make theoretical and technological advances in models of brain repair. Both oral presentation and poster sessions will be used to disseminate information at the meeting. Arrangements have already been made to publish extended abstracts as a journal supplement and to publish the symposium proceedings as a book. This would insure both timely and detailed dissemination of information to the neuroscience community. In addition, Travel Awards for students and postdoctorals with emphasis on underrepresented minorities will be available.
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1992 — 2000 |
Rosenstein, Jeffrey M |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Neural Transplants--Interactions With Developing Brain @ George Washington University
Neural transplantation is well recognized as an important experimental and clinical method for studying problems in neurobiology. The broad long-term objectives of this proposal are to determine the morphological and physiological nature of blood vascular and humoral connectivity between host and graft. Specifically, in the experimental transplantation models attempts will be made to elucidate the nature of alterations in the blood- brain barrier (BBB) and blood-CSF barrier. These models utilize both adrenal medulla and fetal CNS tissue grafts. A major hypothesis is that adrenal medulla, due to its intrinsic vascular permeability can act as a biological portal and permit blood-borne compounds to gain access into the brain and CSF of hosts where normally they would be excluded. These experiments will lay groundwork to investigate not only of whether host-graft connectivity potentially may be affected by vascular neuroactive agents but if normal, fluid homeostasis is altered. To accomplish these aims transplant-bearing rats will receive vascular injections of protein or radiolabeled neurotransmitter and histochemistry, immunohistochemistry and in vivo autoradiography will be performed to determine if both graft and host neurons have access to specific exogenous compounds. CSF content will be evaluated by immuno- affinity chromatography for immunoglobulin. In fetal CNS tissues, further studies will examine specific parameters of BBB deficiency. These include the use of a new monoclonal antibody, endothelial Brain Antigen, for BBB-competent vessels, localization of insulin receptors in brain grafts, and the appearance of certain cellular immunological responses such as the deposition of immune by products (complexes). In addition the functional metabolic and developmental states of grafted neurons will be examined by localization of Neuron Specific Enolase and receptors for growth and vascular related peptides will be examined using in vitro autoradiography. The results of these and future studies will elucidate aspects of BBB properties in neural transplants and may be important for comparisons with certain neurological states when the 888 is compromised.
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2001 |
Rosenstein, Jeffrey M |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Vegf and Angiogenesis in the Cns @ George Washington University
DESCRIPTION (provided by applicant): Vascular endothelial growth factor (VEGF) is a secreted growth factor that plays an important regulatory role in vascular development. VEGF is a significant factor in angiogenesis in the periphery and in tumors and it has already been used clinically for peripheral vascular deficiencies. The proposed experiments will advance our understanding of VEGF and its receptors with respect to brain development and plasticity and may determine if the growth factor plays multiple roles in the CNS. Presently, there exists a paucity of work regarding its direct cellular actions on CNS tissues. The broad long-term goals of this research program are to understand the cellular and molecular interactions of VEGF with CNS tissue with a dual in vitro approach. Experiments use a serum-free organotypic explant system to determine VEGF effects on neuropil at different perinatal developmental stages as well as primary culture assays of neurons, astroglia and isolated CNS vessels. Preliminary data indicate that applied VEGF causes significant angiogenesis in fetal and adult CNS. Unexpectedly, VEGF application also produces significant astroglial proliferation mediated by its flt-1 receptor and enhanced neuronal expression of developmentally regulated proteins and as well as significant neurite outgrowth mediated by its flk-1 receptor. S.A. 1 will examine the angiogenic capacity of applied VEGF to CNS explants as well as the regulation of VEGF receptors and the integrity of the blood-brain barrier. S.A. 2 will test the hypothesis that VEGF acts as a mitogen for astroglia and is a growth factor for CNS neurons in organotypic explants. VEGF receptor and neuronal and astroglial markers will be examined with confocal microscopy, in situ hybridization and quantified by immunoblotting and immunoaffinity chromatography. An innovative technology utilizes microculture chambers to permit real-time microdialysis to determine if VEGF induces production of other cytokines/growth factors. Application of non-specific proteins, anti-sense oligodeoxynucleotides and receptor binding proteins will determine VEGF/receptor specificity in the system. We will also initiate experiments for analysis of receptor signal transduction pathways. S.A. 3 will test comparable parameters in primary cultures in order to verify VEGF's direct effects on CNS elements, absent potential indirect actions between cell types. As an angiogenic factor VEGF could have potential use in cerebrovascular disorders but may also have trophic effects upon astroglia and neurons. The results can lay important cell biological groundwork for understanding how brain tissue might respond to VEGF-based therapy.
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2002 — 2004 |
Rosenstein, Jeffrey M |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Effects of Vegf On Brain Tissue in Vitro @ George Washington University
DESCRIPTION (provided by applicant): Vascular endothelial growth factor (VEGF) is a secreted growth factor that plays an important regulatory role in vascular development. VEGF is a significant factor in angiogenesis in the periphery and in tumors and it has already been used clinically for peripheral vascular deficiencies. The proposed experiments will advance our understanding of VEGF and its receptors with respect to brain development and plasticity and may determine if the growth factor plays multiple roles in the CNS. Presently, there exists a paucity of work regarding its direct cellular actions on CNS tissues. The broad long-term goals of this research program are to understand the cellular and molecular interactions of VEGF with CNS tissue with a dual in vitro approach. Experiments use a serum-free organotypic explant system to determine VEGF effects on neuropil at different perinatal developmental stages as well as primary culture assays of neurons, astroglia and isolated CNS vessels. Preliminary data indicate that applied VEGF causes significant angiogenesis in fetal and adult CNS. Unexpectedly, VEGF application also produces significant astroglial proliferation mediated by its flt-1 receptor and enhanced neuronal expression of developmentally regulated proteins and as well as significant neurite outgrowth mediated by its flk-1 receptor. S.A. 1 will examine the angiogenic capacity of applied VEGF to CNS explants as well as the regulation of VEGF receptors and the integrity of the blood-brain barrier. S.A. 2 will test the hypothesis that VEGF acts as a mitogen for astroglia and is a growth factor for CNS neurons in organotypic explants. VEGF receptor and neuronal and astroglial markers will be examined with confocal microscopy, in situ hybridization and quantified by immunoblotting and immunoaffinity chromatography. An innovative technology utilizes microculture chambers to permit real-time microdialysis to determine if VEGF induces production of other cytokines/growth factors. Application of non-specific proteins, anti-sense oligodeoxynucleotides and receptor binding proteins will determine VEGF/receptor specificity in the system. We will also initiate experiments for analysis of receptor signal transduction pathways. S.A. 3 will test comparable parameters in primary cultures in order to verify VEGF's direct effects on CNS elements, absent potential indirect actions between cell types. As an angiogenic factor VEGF could have potential use in cerebrovascular disorders but may also have trophic effects upon astroglia and neurons. The results can lay important cell biological groundwork for understanding how brain tissue might respond to VEGF-based therapy.
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2003 — 2006 |
Rosenstein, Jeffrey M |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Mechanisms of Vegf Action in Intact and Grafted Cns @ George Washington University
[unreadable] DESCRIPTION (provided by applicant): The purpose of this proposal is .to understand the mechanisms of VEGF action after its administration to the CNS with respect to permeability and angiogenesis and to utilize VEGF's effects to create methods to circumvent the blood-brain barrier (BBB) with minimal invasiveness. Although VEGF and its receptors are known to be upregulated after injury, little information exists on its application to brain tissue. Experiments will attempt to explore models of VEGF as a permeability agent restricted to specific brain areas that will serve as a portal to subsequently allow intravascular administration of compounds that would never cross the BBB rapid access to neuropil. Previous attempts to disrupt the BBB have been global nature and produced random and disseminated openings; in contrast this proposal examines BBB disruption in a strictly focal manner. Aims 1 and 2 examine VEGF angiogenic and permeability effects either after direct focal application by acute or chronic convection enhanced microinfusion (Aim 1) or indirectly using our novel method of grafting isolated clusters of VEGF-treated brain microvessels (Aim 2) to restricted areas of striatum. The spatial and temporal degree of permeability and its receptor-mediation will be examined, and in both Aims we will determine in principle, the feasibility of intravascular delivery of certain non-permeable bioactive compounds such as radiolabeled dopamine (DA), GABA, or the neurotrophic factor, GDNF. Because consistent and effective BBB circumvention is presently perceived as exceptionally difficult problem in neurobiology, the long range goals are to elucidate whether VEGF with its unique permeability, angiogenic and anti-apoptotic properties could be an important agent for molecular delivery in CNS interventional paradigms. These studies may provide impetus for the further design strategies for the circumvention of the BBB and/or the targeting of VEGF receptor mediated effects in brain injury. [unreadable] [unreadable]
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