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Kawamoto A, Gwon HC, Iwaguro H, Yamaguchi JI, Uchida S, Masuda H, Silver M, Ma H, Kearney M, Isner JM, Asahara T. Therapeutic potential of ex vivo expanded endothelial progenitor cells for myocardial ischemia. Circulation 2001; 103:634-7. [PMID: 11156872 DOI: 10.1161/01.cir.103.5.634] [Citation(s) in RCA: 746] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND We investigated the therapeutic potential of ex vivo expanded endothelial progenitor cells (EPCs) for myocardial neovascularization. METHODS AND RESULTS Peripheral blood mononuclear cells obtained from healthy human adults were cultured in EPC medium and harvested 7 days later. Myocardial ischemia was induced by ligating the left anterior descending coronary artery in male Hsd:RH-rnu (athymic nude) rats. A total of 10(6) EPCs labeled with 1,1'-dioctadecyl-1 to 3,3,3',3'-tetramethylindocarbocyanine perchlorate were injected intravenously 3 hours after the induction of myocardial ischemia. Seven days later, fluorescence-conjugated Bandeiraea simplicifolia lectin I was administered intravenously, and the rats were immediately killed. Fluorescence microscopy revealed that transplanted EPCs accumulated in the ischemic area and incorporated into foci of myocardial neovascularization. To determine the impact on left ventricular function, 5 rats (EPC group) were injected intravenously with 10(6) EPCs 3 hours after ischemia; 5 other rats (control group) received culture media. Echocardiography, performed just before and 28 days after ischemia, disclosed ventricular dimensions that were significantly smaller and fractional shortening that was significantly greater in the EPC group than in the control group by day 28. Regional wall motion was better preserved in the EPC group. After euthanization on day 28, necropsy examination disclosed that capillary density was significantly greater in the EPC group than in the control group. Moreover, the extent of left ventricular scarring was significantly less in rats receiving EPCs than in controls. Immunohistochemistry revealed capillaries that were positive for human-specific endothelial cells. CONCLUSIONS Ex vivo expanded EPCs incorporate into foci of myocardial neovascularization and have a favorable impact on the preservation of left ventricular function.
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Bito Y, Kero R, Matsuo H, Shintani Y, Silver M. Interactively visualizing data warehouses. JOURNAL OF HEALTHCARE INFORMATION MANAGEMENT : JHIM 2001; 15:133-42. [PMID: 11452575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
As healthcare costs continue to rise, along with the urgency to control these costs, timely analyses of operational data stored in data warehouses have become critical. Although healthcare organizations have begun to amass large volumes of raw data within data warehouses, many have yet to capitalize on that valuable information. Many clinical and financial events are recorded each day, yet few of these data are leveraged to increase organizational awareness and performance. Because the development and implementation of a data warehouse requires significant time and capital, as well as highly skilled labor, the need to more fully leverage this considerable investment demands techniques that facilitate detailed data exploration, analysis, and the subsequent communication of findings. This article describes how the effective display of complex relationships in data can be used to discover areas of variance in large, changing data warehouses.
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Silver M, Sakata T, Su HC, Herman C, Dolins SB, O'Shea MJ. Case study: how to apply data mining techniques in a healthcare data warehouse. JOURNAL OF HEALTHCARE INFORMATION MANAGEMENT : JHIM 2001; 15:155-64. [PMID: 11452577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Healthcare provider organizations are faced with a rising number of financial pressures. Both administrators and physicians need help analyzing large numbers of clinical and financial data when making decisions. To assist them, Rush-Presbyterian-St. Luke's Medical Center and Hitachi America, Ltd. (HAL), Inc., have partnered to build an enterprise data warehouse and perform a series of case study analyses. This article focuses on one analysis, which was performed by a team of physicians and computer science researchers, using a commercially available on-line analytical processing (OLAP) tool in conjunction with proprietary data mining techniques developed by HAL researchers. The initial objective of the analysis was to discover how to use data mining techniques to make business decisions that can influence cost, revenue, and operational efficiency while maintaining a high level of care. Another objective was to understand how to apply these techniques appropriately and to find a repeatable method for analyzing data and finding business insights. The process used to identify opportunities and effect changes is described.
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Silver M, Flynn JB, Kang S, Drinkwater M, Joyce E, Perls T, Brewster S. Correlation of functional abilities and cognitive status in centenarians: Barthel ADL Index vs. Blessed-Roth IMC test. Arch Clin Neuropsychol 2000. [DOI: 10.1093/arclin/15.8.743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Silver M. Correlation of functional abilities and cognitive status in centenarians: Barthel ADL Index vs. Blessed-Roth IMC test. Arch Clin Neuropsychol 2000. [DOI: 10.1016/s0887-6177(00)80174-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Perls T, Terry DF, Silver M, Shea M, Bowen J, Joyce E, Ridge SB, Fretts R, Daly M, Brewster S, Puca A, Kunkel L. Centenarians and the genetics of longevity. Results Probl Cell Differ 2000; 29:1-20. [PMID: 10838692 DOI: 10.1007/978-3-540-48003-7_1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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108
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Silver M. Conduction issues. J Electrocardiol 2000; 33:297. [PMID: 10954384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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Kalka C, Masuda H, Takahashi T, Kalka-Moll WM, Silver M, Kearney M, Li T, Isner JM, Asahara T. Transplantation of ex vivo expanded endothelial progenitor cells for therapeutic neovascularization. Proc Natl Acad Sci U S A 2000; 97:3422-7. [PMID: 10725398 PMCID: PMC16255 DOI: 10.1073/pnas.97.7.3422] [Citation(s) in RCA: 1085] [Impact Index Per Article: 45.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Animal studies and preliminary results in humans suggest that lower extremity and myocardial ischemia can be attenuated by treatment with angiogenic cytokines. The resident population of endothelial cells that is competent to respond to an available level of angiogenic growth factors, however, may potentially limit the extent to which cytokine supplementation enhances tissue neovascularization. Accordingly, we transplanted human endothelial progenitor cells (hEPCs) to athymic nude mice with hindlimb ischemia. Blood flow recovery and capillary density in the ischemic hindlimb were markedly improved, and the rate of limb loss was significantly reduced. Ex vivo expanded hEPCs may thus have utility as a "supply-side" strategy for therapeutic neovascularization.
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Schratzberger P, Schratzberger G, Silver M, Curry C, Kearney M, Magner M, Alroy J, Adelman LS, Weinberg DH, Ropper AH, Isner JM. Favorable effect of VEGF gene transfer on ischemic peripheral neuropathy. Nat Med 2000; 6:405-13. [PMID: 10742147 DOI: 10.1038/74664] [Citation(s) in RCA: 197] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ischemic peripheral neuropathy is a frequent, irreversible complication of lower extremity vascular insufficiency. We investigated whether ischemic peripheral neuropathy could be prevented and/or reversed by gene transfer of an endothelial cell mitogen designed to promote therapeutic angiogenesis. Intramuscular gene transfer of naked DNA encoding vascular endothelial growth factor (VEGF) simultaneously with induction of hindlimb ischemia in rabbits abrogated the substantial decrease in motor and sensory nerve parameters, and nerve function recovered promptly. When gene transfer was administered 10 days after induction of ischemia, nerve function was restored earlier and/or recovered faster than in untreated rabbits. These findings are due in part to enhanced hindlimb perfusion. In addition, however, the demonstration of functional VEGF receptor expression by Schwann cells indicates a direct effect of VEGF on neural integrity as well. These findings thus constitute a new paradigm for the treatment of ischemic peripheral neuropathy.
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Scholin CA, Gulland F, Doucette GJ, Benson S, Busman M, Chavez FP, Cordaro J, DeLong R, De Vogelaere A, Harvey J, Haulena M, Lefebvre K, Lipscomb T, Loscutoff S, Lowenstine LJ, Marin R, Miller PE, McLellan WA, Moeller PD, Powell CL, Rowles T, Silvagni P, Silver M, Spraker T, Trainer V, Van Dolah FM. Mortality of sea lions along the central California coast linked to a toxic diatom bloom. Nature 2000; 403:80-4. [PMID: 10638756 DOI: 10.1038/47481] [Citation(s) in RCA: 319] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Over 400 California sea lions (Zalophus californianus) died and many others displayed signs of neurological dysfunction along the central California coast during May and June 1998. A bloom of Pseudo-nitzschia australis (diatom) was observed in the Monterey Bay region during the same period. This bloom was associated with production of domoic acid (DA), a neurotoxin that was also detected in planktivorous fish, including the northern anchovy (Engraulis mordax), and in sea lion body fluids. These and other concurrent observations demonstrate the trophic transfer of DA resulting in marine mammal mortality. In contrast to fish, blue mussels (Mytilus edulus) collected during the DA outbreak contained no DA or only trace amounts. Such findings reveal that monitoring of mussel toxicity alone does not necessarily provide adequate warning of DA entering the food web at levels sufficient to harm marine wildlife and perhaps humans.
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Cuffe MS, Califf RM, Adams KF, Bourge RC, Colucci W, Massie B, O'Connor CM, Pina I, Quigg R, Silver M, Robinson LA, Leimberger JD, Gheorghiade M. Rationale and design of the OPTIME CHF trial: outcomes of a prospective trial of intravenous milrinone for exacerbations of chronic heart failure. Am Heart J 2000; 139:15-22. [PMID: 10618557 DOI: 10.1016/s0002-8703(00)90303-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND The optimal management of an acute exacerbation of chronic heart failure (CHF) is uncertain. There is little randomized evidence available to support the various treatment strategies for patients hospitalized with an exacerbation of CHF. Inotropic agents may produce beneficial hemodynamic effects, and although they are currently used in these patients, their effect on clinical response and impact on clinical outcome is unclear. We present a unique and simple study designed to determine whether a treatment strategy for CHF exacerbations that includes an intravenous agent with inotropic properties can reduce hospital length of stay and lead to improved patient outcome. METHODS The OPTIME CHF (Outcomes of a Prospective Trial of Intravenous Milrinone for Exacerbations of Chronic Heart Failure) trial is an ongoing multicenter, randomized, placebo-controlled trial of a treatment strategy for patients with acute exacerbations of CHF. The design of this study provides a novel approach to the evaluation of treatment strategies in the care of this population. The OPTIME CHF design uses early initiation of intravenous milrinone as both an adjunct to the best the medical therapy and to facilitate optimal dosing of standard oral therapy for heart failure. Patients with known systolic heart failure requiring hospital admission for a CHF exacerbation are randomly assigned within 48 hours of admission to receive a 48-hour infusion of either intravenous milrinone or placebo. The primary end point of this design is a reduction in the total hospital days for cardiovascular events within 60 days after therapy. Enrollment of 1000 patients began July 7, 1997, at 80 US centers and is projected to conclude in late 1999.
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Abstract
A retrospective analysis of the health and functional status of centenarians shows they are healthy and independent for most of their lives and experience a relatively rapid terminal decline.
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Asahara T, Masuda H, Takahashi T, Kalka C, Pastore C, Silver M, Kearne M, Magner M, Isner JM. Bone marrow origin of endothelial progenitor cells responsible for postnatal vasculogenesis in physiological and pathological neovascularization. Circ Res 1999; 85:221-8. [PMID: 10436164 DOI: 10.1161/01.res.85.3.221] [Citation(s) in RCA: 2199] [Impact Index Per Article: 88.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Circulating endothelial progenitor cells (EPCs) have been isolated in peripheral blood of adult species. To determine the origin and role of EPCs contributing to postnatal vasculogenesis, transgenic mice constitutively expressing beta-galactosidase under the transcriptional regulation of an endothelial cell-specific promoter (Flk-1/LZ or Tie-2/LZ) were used as transplant donors. Localization of EPCs, indicated by flk-1 or tie-2/lacZ fusion transcripts, were identified in corpus luteal and endometrial neovasculature after inductive ovulation. Mouse syngeneic colon cancer cells (MCA38) were implanted subcutaneously into Flk-1/LZ/BMT (bone marrow transplantation) and Tie-2/LZ/BMT mice; tumor samples harvested at 1 week disclosed abundant flk-1/lacZ and tie-2/lacZ fusion transcripts, and sections stained with X-gal demonstrated that the neovasculature of the developing tumor frequently comprised Flk-1- or Tie-2-expressing EPCs. Cutaneous wounds examined at 4 days and 7 days after skin removal by punch biopsy disclosed EPCs incorporated into foci of neovascularization at high frequency. One week after the onset of hindlimb ischemia, lacZ-positive EPCs were identified incorporated into capillaries among skeletal myocytes. After permanent ligation of the left anterior descending coronary artery, histological samples from sites of myocardial infarction demonstrated incorporation of EPCs into foci of neovascularization at the border of the infarct. These findings indicate that postnatal neovascularization does not rely exclusively on sprouting from preexisting blood vessels (angiogenesis); instead, EPCs circulate from bone marrow to incorporate into and thus contribute to postnatal physiological and pathological neovascularization, which is consistent with postnatal vasculogenesis.
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Asahara T, Takahashi T, Masuda H, Kalka C, Chen D, Iwaguro H, Inai Y, Silver M, Isner JM. VEGF contributes to postnatal neovascularization by mobilizing bone marrow-derived endothelial progenitor cells. EMBO J 1999; 18:3964-72. [PMID: 10406801 PMCID: PMC1171472 DOI: 10.1093/emboj/18.14.3964] [Citation(s) in RCA: 1333] [Impact Index Per Article: 53.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) has been shown to promote neovascularization in animal models and, more recently, in human subjects. This feature has been assumed to result exclusively from its direct effects on fully differentiated endothelial cells, i.e. angiogenesis. Given its regulatory role in both angiogenesis and vasculogenesis during fetal development, we investigated the hypothesis that VEGF may modulate endothelial progenitor cell (EPC) kinetics for postnatal neovascularization. Indeed, we observed an increase in circulating EPCs following VEGF administration in vivo. VEGF-induced mobilization of bone marrow-derived EPCs resulted in increased differentiated EPCs in vitro and augmented corneal neovascularization in vivo. These findings thus establish a novel role for VEGF in postnatal neovascularization which complements its known impact on angiogenesis.
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Fowden AL, Forhead AJ, Bloomfield M, Taylor PM, Silver M. Pancreatic alpha cell function in the fetal foal during late gestation. Exp Physiol 1999; 84:697-705. [PMID: 10481227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Plasma glucagon concentrations were measured in chronically catheterized fetal ponies and their mothers between 260 days of gestation and term (approximately 335 days). Fetal alpha cell responses to arginine and variations in fetal glycaemia were also examined during late gestation. Immunoreactive glucagon was present in fetal plasma at 260 days of gestation and its concentration in utero increased after 320 days and then again at birth. Maternal plasma glucagon concentrations were higher after 300 days than earlier in gestation but were lower than the corresponding fetal value throughout the period of gestation studied. Fetal alpha cells responded rapidly to intravenous arginine infusion but not to changes in the fetal glucose level induced by maternal fasting for 36 h or by intrafetal infusion of glucose. The maximal increment in fetal plasma glucagon in response to arginine occurred at the end of the 5 min infusion and was positively correlated to the basal pre-infusion plasma glucagon concentrations. Fetal plasma glucagon concentrations were unaffected by either hyper- or hypoglycaemia. In contrast, maternal plasma glucagon levels were significantly increased by fasting. These observations indicate that equine pancreatic alpha cells are functional in utero but that they are unresponsive to variations in glycaemia until after birth.
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Couffinhal T, Silver M, Kearney M, Sullivan A, Witzenbichler B, Magner M, Annex B, Peters K, Isner JM. Impaired collateral vessel development associated with reduced expression of vascular endothelial growth factor in ApoE-/- mice. Circulation 1999; 99:3188-98. [PMID: 10377084 DOI: 10.1161/01.cir.99.24.3188] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND The impact of disordered lipid metabolism on collateral vessel development was studied in apolipoprotein (apo)E-/- mice with unilateral hindlimb ischemia. METHODS AND RESULTS Hindlimb blood flow and capillary density were markedly reduced in apoE-/- mice versus C57 controls. This was associated with reduced expression of vascular endothelial growth factor (VEGF) in the ischemic limbs of apoE-/- mice. Cell-specific immunostaining localized VEGF protein expression to skeletal myocytes and infiltrating T cells in the ischemic limbs of C57 mice; in contrast, T-cell infiltrates in ischemic limbs of apoE-/- mice were severely reduced. The critical contribution of T cells to VEGF expression and collateral vessel growth was reinforced by the finding of accelerated limb necrosis in athymic nude mice with operatively induced hindlimb ischemia. Adenoviral VEGF gene transfer to apoE-/- mice resulted in marked augmentation of hindlimb blood flow and capillary density. CONCLUSIONS These findings thus underscore the extent to which hyperlipidemia adversely affects native collateral development but does not preclude augmented collateral vessel growth in response to exogenous cytokines. Moreover, results obtained in the apoE-/- and athymic nude mice imply a critical role for infiltrating T cells as a source of VEGF in neovascularization of ischemic tissues.
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Fabre JE, Rivard A, Magner M, Silver M, Isner JM. Tissue inhibition of angiotensin-converting enzyme activity stimulates angiogenesis in vivo. Circulation 1999; 99:3043-9. [PMID: 10368123 DOI: 10.1161/01.cir.99.23.3043] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Endothelial cells (ECs) represent the critical cellular element responsible for postnatal angiogenesis. Because ACE inhibitors may favorably affect endothelial function, we investigated the hypothesis that administration of the ACE inhibitor quinaprilat could enhance angiogenesis in vivo. METHODS AND RESULTS Ten days after resection of 1 femoral artery, New Zealand White (NZW) rabbits were randomly assigned to receive recombinant human vascular endothelial growth factor (rhVEGF) administered as a single intra-arterial injection (n=6), quinaprilat (n=8) or captopril (n=7) administered as a daily subcutaneous injection, or no treatment (controls, n=6). Angiogenesis was monitored in vivo by measurement of blood pressure, vasoreactivity, and resistance in ischemic versus normal limbs at day 10 (D10) and D40; angiographic studies to identify sites of neovascularization were performed at D10 and D40, and morphometric analysis of capillary density in the ischemic limb was performed at necropsy (D40). Both functional and morphological outcomes documented augmented angiogenesis in quinaprilat-treated rabbits similar to that observed for rhVEGF and superior to that observed with either captopril or no drug (controls). Residual ACE activity was equivalent for the captopril and quinaprilat groups in plasma (42.54+/-0.03% versus 41.53+/-0.02%, P=NS) but not in tissue, where quinaprilat lowered ACE activity significantly (P<0.01) compared with captopril (13% versus 61%). CONCLUSIONS ACE inhibition with quinaprilat promotes angiogenesis in a rabbit model of hindlimb ischemia. Thus, nonsulfhydryl ACE inhibitors with high tissue affinity may be potentially useful for therapeutic angiogenesis in ischemic tissues. Moreover, previous evidence that ACE inhibition benefits patients with myocardial ischemia may be due in part to augmented collateral development.
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Takahashi T, Kalka C, Masuda H, Chen D, Silver M, Kearney M, Magner M, Isner JM, Asahara T. Ischemia- and cytokine-induced mobilization of bone marrow-derived endothelial progenitor cells for neovascularization. Nat Med 1999; 5:434-8. [PMID: 10202935 DOI: 10.1038/7434] [Citation(s) in RCA: 1456] [Impact Index Per Article: 58.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Endothelial progenitor cells (EPCs) have been isolated from circulating mononuclear cells in human peripheral blood and shown to be incorporated into foci of neovascularization, consistent with postnatal vasculogenesis. We determined whether endogenous stimuli (tissue ischemia) and exogenous cytokine therapy (granulocyte macrophage-colony stimulating factor, GM-CSF) mobilize EPCs and thereby contribute to neovascularization of ischemic tissues. The development of regional ischemia in both mice and rabbits increased the frequency of circulating EPCs. In mice, the effect of ischemia-induced EPC mobilization was demonstrated by enhanced ocular neovascularization after cornea micropocket surgery in mice with hindlimb ischemia compared with that in non-ischemic control mice. In rabbits with hindlimb ischemia, circulating EPCs were further augmented after pretreatment with GM-CSF, with a corresponding improvement in hindlimb neovascularization. There was direct evidence that EPCs that contributed to enhanced corneal neovascularization were specifically mobilized from the bone marrow in response to ischemia and GM-CSF in mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase transcriptionally regulated by the endothelial cell-specific Tie-2 promoter. These findings indicate that circulating EPCs are mobilized endogenously in response to tissue ischemia or exogenously by cytokine therapy and thereby augment neovascularization of ischemic tissues.
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Marshall DE, Gower DB, Silver M, Fowden A, Houghton E. Cannulation in situ of equine umbilicus. Identification by gas chromatography-mass spectrometry (GC-MS) of differences in steroid content between arterial and venous supplies to and from the placental surface. J Steroid Biochem Mol Biol 1999; 68:219-28. [PMID: 10416837 DOI: 10.1016/s0960-0760(99)00034-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Equine umbilicus was cannulated in utero and a series of cord plasma samples removed for analysis. After steroid extraction and derivatisation, gas chromatographic-mass spectrometric (GC-MS) analysis demonstrated large differences in steroid content between the plasma samples obtained from the umbilical artery and vein, the blood supplies leading to and from the placental surface, respectively. 3Beta-hydroxy-5,7-androstadien-17-one, dehydroepiandrosterone, pregnenolone, 3beta-hydroxy-5alpha-pregnan-20-one, 5-pregnene-3beta,20beta-diol and 5beta-pregnane-3beta,20beta-diol were identified as major constituents in extracts from umbilical arterial plasma samples, mostly as unconjugated steroids. Together with 5alpha-pregnane-3,20-dione, these steroids were identified in extracts from umbilical venous plasma samples but at significantly reduced levels to those determined in arterial plasma samples. Oestradiol-17alpha, dihydroequilin-17alpha and dihydroequilenin-17alpha were identified in extracts (mostly sulphate-conjugated) from both umbilical arterial and venous plasma samples, much larger amounts being detected in the plasma sampled from, rather than to, the placental surface. Equilin, equilenin, oestrone, oestradiol-17beta, dihydroequilin-17beta and dihydroequilenin-17beta were not detected in the present studies. Isomers of 5(10)-oestrene-3,17beta-diol together with 5(10),7-oestradiene-3,17beta-diol and its possible oxidative artifact, 5(10),7,9-oestratriene-3,17beta-diol, were tentatively identified only in sulphate-conjugated extracts from umbilical venous plasma samples. No glucuronic acid-conjugated steroids could be detected. The implications of this work in the elucidation of the biosynthetic pathways leading to both the formation of oestrogens and C18 neutral steroids at the placental surface are discussed.
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Rivard A, Silver M, Chen D, Kearney M, Magner M, Annex B, Peters K, Isner JM. Rescue of diabetes-related impairment of angiogenesis by intramuscular gene therapy with adeno-VEGF. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 154:355-63. [PMID: 10027394 PMCID: PMC1850015 DOI: 10.1016/s0002-9440(10)65282-0] [Citation(s) in RCA: 371] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/26/1998] [Indexed: 11/19/2022]
Abstract
Diabetes is a major risk factor for coronary and peripheral artery diseases. Although diabetic patients often present with advanced forms of these diseases, it is not known whether the compensatory mechanisms to vascular ischemia are affected in this condition. Accordingly, we sought to determine whether diabetes could: 1) impair the development of new collateral vessel formation in response to tissue ischemia and 2) inhibit cytokine-induced therapeutic neovascularization. Hindlimb ischemia was created by femoral artery ligation in nonobese diabetic mice (NOD mice, n = 20) and in control C57 mice (n = 20). Hindlimb perfusion was evaluated by serial laser Doppler studies after the surgery. In NOD mice, measurement of the Doppler flow ratio between the ischemic and the normal limb indicated that restoration of perfusion in the ischemic hindlimb was significantly impaired. At day 14 after surgery, Doppler flow ratio in the NOD mice was 0.49+/-0.04 versus 0.73+/-0.06 for the C57 mice (P< or =0.005). This impairment in blood flow recovery persisted throughout the duration of the study with Doppler flow ratio values at day 35 of 0.50+/-0.05 versus 0.90+/-0.07 in the NOD and C57 mice, respectively (P< or =0.001). CD31 immunostaining confirmed the laser Doppler data by showing a significant reduction in capillary density in the NOD mice at 35 days after surgery (302+/-4 capillaries/mm2 versus 782+/-78 in C57 mice (P< or =0.005). The reduction in neovascularization in the NOD mice was the result of a lower level of vascular endothelial growth factor (VEGF) in the ischemic tissues, as assessed by Northern blot, Western blot and immunohistochemistry. The central role of VEGF was confirmed by showing that normal levels of neovascularization (compared with C57) could be achieved in NOD mice that had been supplemented for this growth factor via intramuscular injection of an adenoviral vector encoding for VEGF. We conclude that 1) diabetes impairs endogenous neovascularization of ischemic tissues; 2) the impairment in new blood vessel formation results from reduced expression of VEGF; and 3) cytokine supplementation achieved by intramuscular adeno-VEGF gene transfer restores neovascularization in a mouse model of diabetes.
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MESH Headings
- Adenoviridae/genetics
- Animals
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/metabolism
- Endothelial Growth Factors/genetics
- Endothelial Growth Factors/metabolism
- Genetic Therapy
- Genetic Vectors
- Hindlimb/blood supply
- Hindlimb/pathology
- Immunoenzyme Techniques
- Injections, Intramuscular
- Ischemia/pathology
- Ischemia/physiopathology
- Ischemia/therapy
- Laser-Doppler Flowmetry
- Lymphokines/genetics
- Lymphokines/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Inbred NOD
- Muscle, Skeletal/blood supply
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Neovascularization, Pathologic/etiology
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/therapy
- RNA, Messenger/biosynthesis
- Regional Blood Flow
- Vascular Endothelial Growth Factor A
- Vascular Endothelial Growth Factors
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Rivard A, Fabre JE, Silver M, Chen D, Murohara T, Kearney M, Magner M, Asahara T, Isner JM. Age-dependent impairment of angiogenesis. Circulation 1999; 99:111-20. [PMID: 9884387 DOI: 10.1161/01.cir.99.1.111] [Citation(s) in RCA: 492] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The effect of aging on angiogenesis in ischemic vascular disease has not been studied. Accordingly, we investigated the hypothesis that angiogenesis is impaired as a function of age. METHODS AND RESULTS Forty days after the resection of 1 femoral artery, collateral vessel development was significantly impaired in old (aged 4 to 5 years; n=7) versus young (aged 6 to 8 months; n=6) New Zealand White (NZW) rabbits on the basis of reduced hindlimb perfusion (ischemic: normal blood pressure ratio=0.58+/-0.05 versus 0.77+/-0.06; P<0.005), reduced number of angiographically visible vessels (angiographic score=0.48+/-0.05 versus 0.70+/-0.05; P<0.01), and lower capillary density in the ischemic limb (130.3+/-5.8/mm2 versus 171.4+/-9.5/mm2; P<0.001). Angiogenesis was also impaired in old (aged 2 years) versus young (aged 12 weeks) mice as shown by reduced hindlimb perfusion (measured by laser Doppler imaging) and lower capillary density (353.0+/-14.3/mm2 versus 713.3+/-63.4/mm2; P<0.01). Impaired angiogenesis in old animals was the result of impaired endothelial function (lower basal NO release and decreased vasodilation in response to acetylcholine) and a lower expression of vascular endothelial growth factor (VEGF) in ischemic tissues (by Northern blot, Western blot, and immunohistochemistry). When recombinant VEGF protein was administered to young and old rabbits, both groups exhibited a significant and similar increase in blood pressure ratio, angiographic score, and capillary density. CONCLUSIONS Angiogenesis responsible for collateral development in limb ischemia is impaired with aging; responsible mechanisms include age-related endothelial dysfunction and reduced VEGF expression. Advanced age, however, does not preclude augmentation of collateral vessel development in response to exogenous angiogenic cytokines.
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Silver M, Newell K, Hedley-White ET, Growden J, Hyman B, Perls T. Cognitive functioning of two centenarians with left hippocampal lesions. Arch Clin Neuropsychol 1999. [DOI: 10.1093/arclin/14.1.65a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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124
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Rahmani R, Dixon M, Chitayat D, Korb E, Silver M, Barozzino T, Toi A. Otocephaly: prenatal sonographic diagnosis. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 1998; 17:595-598. [PMID: 9733181 DOI: 10.7863/jum.1998.17.9.595] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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125
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Witzenbichler B, Asahara T, Murohara T, Silver M, Spyridopoulos I, Magner M, Principe N, Kearney M, Hu JS, Isner JM. Vascular endothelial growth factor-C (VEGF-C/VEGF-2) promotes angiogenesis in the setting of tissue ischemia. THE AMERICAN JOURNAL OF PATHOLOGY 1998; 153:381-94. [PMID: 9708799 PMCID: PMC1852989 DOI: 10.1016/s0002-9440(10)65582-4] [Citation(s) in RCA: 246] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Recently, vascular endothelial growth factor-C (VEGF-C or VEGF-2) was described as a specific ligand for the endothelial receptor tyrosine kinases VEGFR-2 and VEGFR-3. In vivo data, limited to constitutive overexpression in transgenic mice, have been interpreted as evidence that the growth-promoting effects of VEGF-C are restricted to development of the lymphatic vasculature. The current studies were designed to test the hypothesis that constitutive expression of VEGF-C in adult animals promotes angiogenesis. In vitro, VEGF-C exhibited a dose-dependent mitogenic and chemotactic effect on endothelial cells, particularly for microvascular endothelial cells (72% and 95% potency, respectively, compared with VEGF-A/VEGF-1). VEGF-C stimulated release of nitric oxide from endothelial cells and increased vascular permeability in the Miles assay; the latter effect was attenuated by pretreatment with the nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methyl ester. Both VEGFR-2 and VEGFR-3 receptors were shown to be expressed in human saphenous vein and internal mammary artery. The potential for VEGF-C to promote angiogenesis in vivo was then tested in a rabbit ischemic hindlimb model. Ten days after ligation of the external iliac artery, VEGF-C was administered as naked plasmid DNA (pcVEGF-C; 500 microg) from the polymer coating of an angioplasty balloon (n = 8 each) or as recombinant human protein (rhVEGF-C; 500 microg) by direct intra-arterial infusion. Physiological and anatomical assessments of angiogenesis 30 days later showed evidence of therapeutic angiogenesis for both pcVEGF-C and rhVEGF-C. Hindlimb blood pressure ratio (ischemic/normal) after pcVEGF-C increased to 0.83 +/- 0.03 after pcVEGF-C versus 0.59 +/- 0.04 (P < 0.005) in pGSVLacZ controls and to 0.76 +/- 0.04 after rhVEGF-C versus 0.58 +/- 0.03 (P < 0.01) in control rabbits receiving rabbit serum albumin. Doppler-derived iliac flow reserve was 2.7 +/- 0.1 versus 2.0 +/- 0.2 (P < 0.05) for pcVEGF-C versus LacZ controls and 2.9 +/- 0.3 versus 2.1 +/- 0.2 (P < 0.05) for rhVEGF-C versus albumin controls. Neovascularity was documented by angiography in vivo (angiographic scores: 0.85 +/- 0.05 versus 0.51 +/- 0.02 (P < 0.001) for plasmid DNA and 0.74 +/- 0.08 versus 0.53 +/- 0.03 (P < 0.05) for protein), and capillary density (per mm2) was measured at necropsy (252 +/- 12 versus 183 +/- 10 (P < 0.005) for plasmid DNA and 229 +/- 20 versus 164 +/- 20 (P < 0.05) for protein). In contrast to the results of gene targeting experiments, constitutive expression of VEGF-C in adult animals promotes angiogenesis in the setting of limb ischemia. VEGF-C and its receptors thus constitute an apparently redundant pathway for postnatal angiogenesis and may represent an alternative to VEGF-A for strategies of therapeutic angiogenesis in patients with limb and/or myocardial ischemia.
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MESH Headings
- Angiography
- Animals
- Capillary Permeability/drug effects
- Cell Division/drug effects
- Cell Movement/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- Endothelial Growth Factors/genetics
- Endothelial Growth Factors/pharmacology
- Endothelial Growth Factors/physiology
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Gene Transfer Techniques
- Guinea Pigs
- Hindlimb/blood supply
- Histocytochemistry
- Humans
- Injections, Intra-Arterial
- Ischemia
- Male
- NG-Nitroarginine Methyl Ester/pharmacology
- Neovascularization, Physiologic/drug effects
- Neovascularization, Physiologic/genetics
- Nitric Oxide/biosynthesis
- Nitric Oxide/physiology
- RNA, Messenger/analysis
- Rabbits
- Receptor Protein-Tyrosine Kinases/genetics
- Receptors, Growth Factor/genetics
- Receptors, Vascular Endothelial Growth Factor
- Recombinant Proteins/pharmacology
- Vascular Endothelial Growth Factor C
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Murohara T, Asahara T, Silver M, Bauters C, Masuda H, Kalka C, Kearney M, Chen D, Symes JF, Fishman MC, Huang PL, Isner JM. Nitric oxide synthase modulates angiogenesis in response to tissue ischemia. J Clin Invest 1998; 101:2567-78. [PMID: 9616228 PMCID: PMC508846 DOI: 10.1172/jci1560] [Citation(s) in RCA: 913] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
We tested the hypothesis that endothelial nitric oxide synthase (eNOS) modulates angiogenesis in two animal models in which therapeutic angiogenesis has been characterized as a compensatory response to tissue ischemia. We first administered L-arginine, previously shown to augment endogenous production of NO, to normal rabbits with operatively induced hindlimb ischemia. Angiogenesis in the ischemic hindlimb was significantly improved by dietary supplementation with L-arginine, compared to placebo-treated controls; angiographically evident vascularity in the ischemic limb, hemodynamic indices of limb perfusion, capillary density, and vasomotor reactivity in the collateral vessel-dependent ischemic limb were all improved by oral L-arginine supplementation. A murine model of operatively induced hindlimb ischemia was used to investigate the impact of targeted disruption of the gene encoding for ENOS on angiogenesis. Angiogenesis in the ischemic hindlimb was significantly impaired in eNOS-/- mice versus wild-type controls evaluated by either laser Doppler flow analysis or capillary density measurement. Impaired angiogenesis in eNOS-/- mice was not improved by administration of vascular endothelial growth factor (VEGF), suggesting that eNOS acts downstream from VEGF. Thus, (a) eNOS is a downstream mediator for in vivo angiogenesis, and (b) promoting eNOS activity by L-arginine supplementation accelerates in vivo angiogenesis. These findings suggest that defective endothelial NO synthesis may limit angiogenesis in patients with endothelial dysfunction related to atherosclerosis, and that oral L-arginine supplementation constitutes a potential therapeutic strategy for accelerating angiogenesis in patients with advanced vascular obstruction.
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Couffinhal T, Silver M, Zheng LP, Kearney M, Witzenbichler B, Isner JM. Mouse model of angiogenesis. THE AMERICAN JOURNAL OF PATHOLOGY 1998; 152:1667-79. [PMID: 9626071 PMCID: PMC1858441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Neovascularization of ischemic muscle may be sufficient to preserve tissue integrity and/or function and may thus be considered to be therapeutic. The regulatory role of vascular endothelial growth factor (VEGF) in therapeutic angiogenesis was suggested by experiments in which exogenously administered VEGF was shown to augment collateral blood flow in animals and patients with experimentally induced hindlimb or myocardial ischemia. To address the possible contribution of postnatal endogenous VEGF expression to collateral vessel development in ischemia tissues, we developed a mouse model of hindlimb ischemia. The femoral artery of one hindlimb was ligated and excised. Laser Doppler perfusion imaging (LDPI) was employed to document the consequent reduction in hindlimb blood flow, which typically persisted for up to 7 days. Serial in vivo examinations by LDPI disclosed that hindlimb blood flow was progressively augmented over the course of 14 days, ultimately reaching a plateau between 21 and 28 days. Morphometric analysis of capillary density performed at the same time points selected for in vivo analysis of blood flow by LDPI confirmed that the histological sequence of neovascularization corresponded temporally to blood flow recovery detected in vivo. Endothelial cell proliferation was documented by immunostaining for bromodeoxyuridine injected 24 hours before each of these time points, providing additional evidence that angiogenesis constitutes the basis for improved collateral-dependent flow in this animal model. Neovascularization was shown to develop in association with augmented expression of VEGF mRNA and protein from skeletal myocytes as well as endothelial cells in the ischemic hindlimb; that such reparative angiogenesis is indeed dependent upon VEGF up-regulation was confirmed by impaired neovascularization after administration of a neutralizing VEGF antibody. Sequential characterization of the in vivo, histological, and molecular findings in this novel animal model thus document the role of VEGF as endogenous regulator of angiogenesis in the setting of tissue ischemia. Moreover, this murine model represents a potential means for studying the effects of gene targeting on nutrient angiogenesis in vivo.
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Kennedy D, Chitayat D, Winsor EJ, Silver M, Toi A. Prenatally diagnosed neural tube defects: ultrasound, chromosome, and autopsy or postnatal findings in 212 cases. AMERICAN JOURNAL OF MEDICAL GENETICS 1998; 77:317-21. [PMID: 9600743 DOI: 10.1002/(sici)1096-8628(19980526)77:4<317::aid-ajmg13>3.0.co;2-l] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
From January 1990 until December 1996, 212 cases of neural tube defect (NTD) were seen through the Prenatal Diagnosis Program of the University of Toronto. Of the 212 cases, 200 were karyotyped successfully and of these, 13 (6.5%) had chromosome abnormalities. When classified according to the site of the NTD, 2.3% (2/88) of anencephalics, 7.1% (1/14) of encephaloceles, and 10.2% (10/98) of meningomyeloceles had abnormal karyotypes. The absence of associated ultrasound abnormalities was not necessarily predictive of a chromosomally normal fetus; 4/167 (2.4%) of fetuses with isolated NTDs had chromosome abnormalities. Conversely, 24/33 (72%) of fetuses with additional findings on ultrasound had normal chromosomes. The diagnosis of a chromosome abnormality associated with NTD has important implications for recurrence risk and prenatal diagnosis, not only for the parents but potentially for other relatives. Based on our finding that 6.5% of prenatally detected NTDs are associated with chromosome abnormalities, we recommend karyotyping of all fetuses and/or newborns with NTD.
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129
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Fowden AL, Mundy L, Silver M. Developmental regulation of glucogenesis in the sheep fetus during late gestation. J Physiol 1998; 508 ( Pt 3):937-47. [PMID: 9518744 PMCID: PMC2230917 DOI: 10.1111/j.1469-7793.1998.937bp.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
1. Using tracer methodology, endogenous glucose production was measured in twenty-six chronically catheterized sheep fetuses during normal fed conditions and in response to a 48 h period of maternal fasting at different gestational ages during the last 10-15 days of gestation (term, 145 +/- 2 days). 2. In normal fed conditions, the rate of fetal glucose production was negligible until 143-145 days when it rose significantly to account for 50 % of the glucose used by the fetus. The rise in fetal glucogenesis towards term closely parallelled the normal prepartum rise in fetal plasma cortisol and catecholamines. 3. Maternal fasting for 48 h induced endogenous glucose production in fetuses at 139-141 days but not at 133-135 days of gestation. Maternal fasting also induced increases in the plasma cortisol and noradrenaline levels in all the fetuses studied. Fetal plasma cortisol levels at the end of the fast and the increment in fetal plasma cortisol during maternal fasting were significantly greater in the older groups of fasted animals. 4. When the data from all the fetuses were combined, partial correlation analysis of fetal glucose production and the log plasma concentrations of cortisol and total catecholamines showed that plasma cortisol was the predominant regulator of fetal glucogenesis during late gestation. However, once plasma cortisol levels exceeded 17.5 ng ml-1, plasma catecholamines were a major influence on fetal glucogenesis. 5. The results show that glucogenesis occurs in fetal sheep during late gestation in conditions in which the fetal plasma concentrations of cortisol and catecholamines are elevated. They also suggest that cortisol enhances the capacity for glucogenesis in utero, while catecholamines actually activate glucose production in sheep fetuses close to term.
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130
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Moniz-Cook E, Agar S, Silver M, Woods R, Wang M, Elston C, Win T. Can staff training reduce behavioural problems in residential care for the elderly mentally ill? Int J Geriatr Psychiatry 1998; 13:149-58. [PMID: 9565836 DOI: 10.1002/(sici)1099-1166(199803)13:3<149::aid-gps746>3.0.co;2-q] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The effect of a brief in-service training programme on the psychosocial management of behavioural disturbance in residential care is described. Although the incidence of problematic behaviour did not change 3 months after training, staff in the experimental homes reported a significant improvement in their management of problematic behaviour, as compared to the control home. However, these effects were not maintained a year later. The importance of post-training supervision and the sociocultural context of the home in the maintenance of psychosocial intervention in residential settings is discussed.
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131
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Silver M, Newell K, Hyman B, Growdon J, Hedley-Whyte ET, Perls T. Unraveling the mystery of cognitive changes in old age: correlation of neuropsychological evaluation with neuropathological findings in the extreme old. Int Psychogeriatr 1998; 10:25-41. [PMID: 9629522 DOI: 10.1017/s1041610298005122] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In order to understand what cognitive changes can be expected with aging versus those caused by disease, the New England Centenarian Study examined correlations between neuropsychological evaluation and neuropathological studies of centenarian subjects. Sixty-nine subjects were administered an extensive neuropsychological test battery designed for centenarians. Six brain donors from this group have subsequently died, and neuropathological studies of their brains have been performed to determine the presence of Alzheimer's disease (AD) and other pathological states. Of these six centenarians, three subjects had Clinical Dementia Rating scores of 0 and no dementia on neuropsychological testing, and subsequent neuropathology showed very limited AD changes. In fact, despite a range of neuropsychological findings, none of the subjects in this series met neuropathological criteria for a diagnosis of definite AD. Findings suggest that dementia is not inevitable with aging and that dementia in this age group is surprisingly often not attributable to AD.
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Sata M, Perlman H, Muruve DA, Silver M, Ikebe M, Libermann TA, Oettgen P, Walsh K. Fas ligand gene transfer to the vessel wall inhibits neointima formation and overrides the adenovirus-mediated T cell response. Proc Natl Acad Sci U S A 1998; 95:1213-7. [PMID: 9448311 PMCID: PMC18722 DOI: 10.1073/pnas.95.3.1213] [Citation(s) in RCA: 118] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Proliferation of vascular smooth muscle cells (VSMCs) in response to injury plays a key role in the pathogenesis of vascular disorders. Fas ligand (FasL) induces apoptosis in Fas-bearing cells, and its expression on activated T cells contributes to the regulation of the immune response and physiological cell turnover. Here, we show that a replication-defective adenovirus encoding FasL (Ad-FasL) induced apoptosis in Fas-bearing VSMCs. When introduced locally to balloon-injured rat carotid arteries, a well characterized model of a VSMC-derived lesion, Ad-FasL functioned as a potent inhibitor of neointima formation. In rats immunized with an empty adenoviral vector, robust T cell infiltration of the vessel wall was detected after local delivery of a beta-galactosidase-expressing virus (Ad-betagal), whereas T cell infiltrates were not detected after local delivery of Ad-FasL. Prior immunization prevented beta-galactosidase expression from Ad-betagal, whereas the expression of the FasL transgene was unaffected. When Ad-betagal and Ad-FasL were delivered together to preimmunized animals, T cell infiltration was reduced and beta-galactosidase expression was restored. These data demonstrate that Fas ligand gene transfer can effectively inhibit injury-induced vessel lesion formation and can allow adenovirus-harboring cells to evade immune destruction.
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MESH Headings
- Adenoviridae Infections/pathology
- Angioplasty, Balloon/adverse effects
- Animals
- Apoptosis
- DNA Fragmentation
- Endothelium, Vascular/injuries
- Endothelium, Vascular/pathology
- Fas Ligand Protein
- Gene Transfer Techniques
- Humans
- Jurkat Cells
- Ligands
- Male
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/immunology
- Muscle, Smooth, Vascular/immunology
- Muscle, Smooth, Vascular/injuries
- Muscle, Smooth, Vascular/pathology
- Rats
- Rats, Sprague-Dawley
- T-Lymphocytes/immunology
- T-Lymphocytes/virology
- fas Receptor/genetics
- fas Receptor/immunology
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133
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Van Belle E, Witzenbichler B, Chen D, Silver M, Chang L, Schwall R, Isner JM. Potentiated angiogenic effect of scatter factor/hepatocyte growth factor via induction of vascular endothelial growth factor: the case for paracrine amplification of angiogenesis. Circulation 1998; 97:381-90. [PMID: 9468212 DOI: 10.1161/01.cir.97.4.381] [Citation(s) in RCA: 297] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Scatter factor/hepatocyte growth factor (SF/HGF) is a pleiotropic growth factor that stimulates proliferation and migration of endothelial cells (ECs) via the c-Met receptor, present on ECs as well as other cell types, including smooth muscle cells (SMCs). We studied the effects of recombinant human (rh) SF/HGF in vitro and in vivo in a rabbit model of hindlimb ischemia. We further compared these effects with those of recombinant human vascular endothelial growth factor (rhVEGF165), an EC-specific mitogen. METHODS AND RESULTS In vitro, rhSF/HGF and rhVEGF165 exhibited similar effects on proliferation and migration of ECs. When both cytokines were administered together, the result was an additive effect on EC proliferation and a synergistic effect on EC migration. Application of rhSF/HGF to cultures of human SMCs resulted in the induction of VEGF mRNA and protein. In vivo, administration of rhSF/HGF (500 microg x 3) was associated with significant improvements in collateral formation (P<.001) and regional blood flow (P<.0005) and with a significant reduction in muscle atrophy (P<.0001). These effects were significantly more pronounced than those of rhVEGF165 administered according to the same protocol (P<.05). Neither remote angiogenesis nor other pathological sequelae were observed with either rhSF/HGF or rhVEGF165. CONCLUSIONS The pleiotropic effects of certain growth factors may potentiate angiogenesis via a combination of direct effects on EC proliferation and migration and indirect effects that result in the generation of other potent EC mitogens from non-EC populations. The synergistic effects demonstrated when SF/HGF and VEGF are administered together in vitro may be reproduced in vivo by SF/HGF-induced upregulation of VEGF in vascular SMCs.
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MESH Headings
- Animals
- Blood Pressure/drug effects
- Cell Movement/physiology
- Cells, Cultured
- Collateral Circulation/drug effects
- Endothelial Growth Factors/genetics
- Endothelial Growth Factors/pharmacology
- Endothelial Growth Factors/physiology
- Hepatocyte Growth Factor/pharmacology
- Hepatocyte Growth Factor/physiology
- Hindlimb/blood supply
- Humans
- Iliac Artery/drug effects
- Iliac Artery/physiopathology
- Ischemia/physiopathology
- Lymphokines/genetics
- Lymphokines/pharmacology
- Lymphokines/physiology
- Male
- Muscle, Skeletal/blood supply
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiology
- Neovascularization, Physiologic/physiology
- RNA, Messenger/metabolism
- Rabbits
- Recombinant Proteins
- Regional Blood Flow/drug effects
- Vascular Endothelial Growth Factor A
- Vascular Endothelial Growth Factors
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Silver M. Use of a Novel Anti-Apoptotic Agent (LXR017) Reduces Infarct Size Following Ischemia-Reperfusion in the Canine Myocardium. J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(97)83994-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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135
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Murohara T, Horowitz JR, Silver M, Tsurumi Y, Chen D, Sullivan A, Isner JM. Vascular endothelial growth factor/vascular permeability factor enhances vascular permeability via nitric oxide and prostacyclin. Circulation 1998; 97:99-107. [PMID: 9443437 DOI: 10.1161/01.cir.97.1.99] [Citation(s) in RCA: 372] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Vascular endothelial growth factor (VEGF), an endothelial cell mitogen that promotes angiogenesis, was initially identified as a vascular permeability factor (VPF). Abundant evidence suggests that angiogenesis is preceded and/or accompanied by enhanced microvascular permeability. The mechanism by which VEGF/VPF increases vascular permeability (VP), however, has remained enigmatic. Accordingly, we used an in vivo assay of VP (Miles assay) to study the putative mediators of VEGF/VPF-induced permeability. METHODS AND RESULTS VEGF/VPF and positive controls (platelet-activating factor [PAF], histamine, and bradykinin) all increased vascular permeability. Prior administration of the tyrosine kinase inhibitors genistein or herbimycin A prevented VEGF/VPF-induced permeability. Placenta growth factor, which binds to Flt-1/VEGF-R1 but not Flk-1/KDR/VEGF-R2 receptor tyrosine kinase, failed to increase permeability. Other growth factors such as basic fibroblast growth factor (FGF), acidic FGF, platelet-derived growth factor-BB, transforming growth factor-beta, scatter factor, and granulocyte macrophage-colony stimulating factor (8 to 128 ng) failed to increase permeability. VEGF/VPF-induced permeability was significantly attenuated by the nitric oxide (NO) synthase inhibitors N(omega)-nitro-L-arginine (10 mg/kg) or N(omega)-nitro-L-arginine methyl ester (20 mg/kg) and the cyclooxygenase inhibitor indomethacin (5 mg/kg). The inactive enantiomer N(omega)-nitro-D-arginine methyl ester (20 mg/kg) did not inhibit VEGF/VPF-induced permeability. In vitro studies confirmed that VEGF/VPF stimulates synthesis of NO and prostaglandin metabolites in microvascular endothelial cells. Finally, NO donors and the prostacyclin analogue taprostene administered together but not alone reproduced the increase in permeability observed with VEGF/VPF. CONCLUSIONS These results implicate NO and prostacyclin produced by the interaction of VEGF/VPF with its Flk-1/KDR/VEGF-R2 receptor as mediators of VEGF/VPF-induced vascular permeability. Moreover, this property appears unique to VEGF/VPF among angiogenic cytokines.
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Silver M. Fresh approaches stave off competition. Silver Care Center thrives on its administrator's ingenuity and energy. Interview by Kelley Sheahan. BALANCE (ALEXANDRIA, VA.) 1998; 2:20-1, 28. [PMID: 10178524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
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137
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Tsurumi Y, Kearney M, Chen D, Silver M, Takeshita S, Yang J, Symes JF, Isner JM. Treatment of acute limb ischemia by intramuscular injection of vascular endothelial growth factor gene. Circulation 1997; 96:II-382-8. [PMID: 9386128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Ischemic skeletal muscle has been shown to be advantageous for taking up and expressing genes transferred in the form of naked plasmid DNA. Therefore, acutely ischemic skeletal muscle may represent a potential target for IM gene therapy with naked DNA. Accordingly, we investigated the impact of IM injection of plasmid DNA encoding the secreted angiogenic growth factor, vascular endothelial growth factor (VEGF), on collateral vessel development in an animal model of acute hindlimb ischemia. METHODS AND RESULTS After ligation of distal external iliac artery in New Zealand White rabbits, we directly injected 500 microg of phVEGF165 into the ischemic thigh muscles. At 30 days posttransfection, VEGF-transfected animals had more angiographically recognizable collateral vessels (angiographic score=0.72+/-0.06 versus 0.48+/-0.10; P<.01) as well as histologically assessed capillaries (248+/-37 versus 180+/-32/mm2, P<.01) compared to controls. Hemodynamic deficit was less severe in VEGF-transfected animals by calf systolic blood pressure ratio (0.80+/-0.09 versus 0.56+/-0.10, P<.01) and by flow to the ischemic limb measured with Doppler guidewire (resting flow=22+/-5 versus 14+/-4; P<.01; hyperemic flow=59+/-17 versus 39+/-12 mL/min; P<.05). Human VEGF mRNA was expressed in the transfected ischemic muscles as long as 14 days after gene transfer. Based on reporter plasmid expression, transfection efficiency was sixfold higher in ischemic muscles than in nonischemic control muscles. CONCLUSIONS These results suggest the feasibility of employing direct IM transfer of naked VEGF plasmid DNA to optimize treatment of acute limb ischemia.
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138
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Tse G, Silver M, Whyte H, Jay V. Neonatal meningitis and multiple brain abscesses due to Citrobacter diversus. PEDIATRIC PATHOLOGY & LABORATORY MEDICINE : JOURNAL OF THE SOCIETY FOR PEDIATRIC PATHOLOGY, AFFILIATED WITH THE INTERNATIONAL PAEDIATRIC PATHOLOGY ASSOCIATION 1997; 17:977-82. [PMID: 9353837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We report a fatal sporadic case of neonatal Citrobacter diversus meningitis with rapid clinical progression. At autopsy, multiple brain abscesses and abscesses in the spinal cord had complicated purulent meningitis. Septic omphalitis was identified as the most likely portal of entry.
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139
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Van Belle E, Rivard A, Chen D, Silver M, Bunting S, Ferrara N, Symes JF, Bauters C, Isner JM. Hypercholesterolemia attenuates angiogenesis but does not preclude augmentation by angiogenic cytokines. Circulation 1997; 96:2667-74. [PMID: 9355908 DOI: 10.1161/01.cir.96.8.2667] [Citation(s) in RCA: 126] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The impact of hyperlipidemia on collateral vessel development in vivo remains enigmatic. We sought to determine the anatomic extent and functional capacity of the collateral bed that develops in response to limb ischemia in a well characterized animal model of spontaneous hypercholesterolemia, the Watanabe heritable hyperlipidemic (WHHL) rabbit. We further characterized the impact of exogenous angiogenic cytokine administration on collateral vessel development and function in the same animal model. METHODS AND RESULTS Weight-matched 6-month-old male homozygous WHHL (n=9) and normal New Zealand White (NZW) (n=9) rabbits underwent surgical resection of one femoral artery. Ten days later, the ischemic hindlimb was evaluated for collateral vessel formation, blood flow, and tissue damage. Collateral vasculature was less extensive among WHHL than NZW, as indicated by a significant reduction in angiographic score (0.19+/-0.02 versus 0.35+/-0.03, P<.001) and capillary density (46.4+/-4.1 versus 78.9+/-4.6/mm2, P<.0002). This was associated with a reduction in calf blood pressure index (9.5+/-3.5% versus 32.8+/-2.8%, P<.0001), arterial blood flow (7.5+/-0.6 versus 13.6+/-0.7 mL/min, P<.0001), and muscle perfusion index (40.1+/-3.2% versus 65.9+/-2.0%, P<.0001) and an increase in muscle necrosis (48.16+/-5.41% versus 25.90+/-3.83% negative 2,3,5-triphenyltetrazolium chloride staining, P<.004). Treatment of WHHL rabbits (n=9) with recombinant human vascular endothelial growth factor produced a statistically significant improvement in all functional as well as anatomic indices of collateral development. CONCLUSIONS Collateral vessel development associated with hindlimb ischemia in vivo is severely attenuated in an animal model of spontaneous hypercholesterolemia but nevertheless may be augmented by administration of angiogenic cytokines.
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Siziopikou KP, Ahn MC, Casey L, Silver M, Harris JE, Braun DP. Augmentation of impaired tumoricidal function in alveolar macrophages from lung cancer patients by cocultivation with allogeneic, but not autologous lymphocytes. Cancer Immunol Immunother 1997; 45:29-36. [PMID: 9353424 PMCID: PMC11037803 DOI: 10.1007/s002620050397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/1997] [Accepted: 06/11/1997] [Indexed: 02/05/2023]
Abstract
It has been reported that the in vitro development of tumoricidal function in alveolar macrophages from lung cancer patients is reduced significantly when compared to that in peripheral blood monocytes from the same patients or alveolar macrophages from control patients. In the present investigation, a method for potentiating the development of tumoricidal function in alveolar macrophages from lung cancer patients is described. This method, which relies on priming the macrophages with purified, allogeneic peripheral blood lymphocytes from normal donors, could not be demonstrated when autologous lymphocytes from lung cancer patients were used in the priming coculture. The augmentation of tumoricidal function appears to be mediated by one or more soluble factors, since supernatants from cocultures of alveolar macrophages and allogeneic peripheral blood lymphocytes could enhance the cytotoxic function of freshly obtained alveolar macrophages. Furthermore, it appears that NK cells are necessary for this effect, since depletion of CD56+/CD57+ cells from allogeneic lymphocytes eliminated their capacity to enhance alveolar macrophage cytotoxic function. The augmentation of cytotoxic function elicited in alveolar macrophages by this method was not associated with changes in the secretion of tumor necrosis factor alpha, or interleukin 1 beta.
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141
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Ahn MC, Siziopikou KP, Plate JM, Casey L, Silver M, Harris JE, Braun DP. Modulation of tumoricidal function in alveolar macrophages from lung cancer patients by interleukin-6. Cancer Immunol Immunother 1997; 45:37-44. [PMID: 9353425 PMCID: PMC11037664 DOI: 10.1007/s002620050398] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/1997] [Accepted: 06/11/1997] [Indexed: 02/07/2023]
Abstract
Previous studies have demonstrated that alveolar macrophages from lung cancer patients are impaired in their ability to develop tumoricidal function when stimulated by activators such as interferon gamma + lipopolysaccharide. However, these same macrophages have been shown to develop significant tumoricidal function when precultured with macrophage-depleted allogeneic peripheral blood lymphocytes from normal donors, an effect that was lost by the elimination of natural killer cells from the allogeneic lymphocyte population. In the present study, the effect of each activation condition on the expression of mRNA for interleukin-1 alpha (IL-1 alpha), IL-1 beta, tumor necrosis factor alpha (TNF alpha) and IL-6 was determined using reverse transcription/polymerase chain reaction. The results show that the non-permissive activation condition is associated with the expression of mRNA for IL-6 while the permissive activation condition is not. Antibodies against IL-6 were subsequently shown to permit the development of tumoricidal function in alveolar macrophages stimulated with interferon gamma + lipopolysaccharide while IL-6 protein was shown to inhibit the stimulatory action of allogeneic lymphocytes on the development of tumoricidal function in the same alveolar macrophages. Neither the permissive (i.e. allogeneic lymphocyte stimulation) nor the non-permissive (i.e. interferon gamma + lipopolysaccharide) activation condition had any effect on the capacity of alveolar macrophages from lung cancer patients to express mRNA for IL-1 alpha, IL-1 beta or TNF alpha. These results show that IL-6 can regulate the ability of alveolar macrophages from lung cancer patients to be stimulated by interferon gamma + lipopolysaccharide to develop significant tumoricidal function. They also show that allogeneic lymphocytes have the capacity to down-regulate IL-6 mRNA synthesis by alveolar macrophages thereby permitting the development and/or expression of macrophage tumoricidal function.
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142
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Tabata H, Silver M, Isner JM. Arterial gene transfer of acidic fibroblast growth factor for therapeutic angiogenesis in vivo: critical role of secretion signal in use of naked DNA. Cardiovasc Res 1997; 35:470-9. [PMID: 9415291 DOI: 10.1016/s0008-6363(97)00152-1] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE Previous studies have demonstrated that arterial gene transfer of naked DNA encoding for a secreted protein may permit modulation of the host phenotype despite a low transfection efficiency. Acidic fibroblast growth factor (aFGF) is an angiogenic growth factor, but is not secreted by intact cells. In the current study, we investigated the hypothesis that addition of a hydrophobic leader sequence to achieve active secretion of the gene product would permit therapeutic angiogenesis following arterial gene transfer of naked DNA encoding for aFGF. METHODS Ten days following surgical induction of unilateral hindlimb ischemia, New Zealand white rabbits were randomized to intra-arterial gene transfer with one of three plasmids: p267 (encoding non-secreted aFGF, n = 10), pMJ35 (encoding secreted aFGF) (n = 10), or 500 micrograms of pGSVLacZ (control, n = 10) (500 micrograms each). All animals were studied at 30 days post-gene transfer for evidence of therapeutic angiogenesis. RESULTS pMJ35 transfectants had more angiographically visible collaterals (angiographic score = 0.76 +/- 0.02) than either p267 (0.55 +/- 0.02, p < 0.01) or LacZ (0.47 +/- 0.02, p < 0.001). Limb blood pressure ratio for pMJ35 was 0.88 +/- 0.02 vs. 0.68 +/- 0.04 for p267 (p < 0.01) and 0.57 +/- 0.04 for LacZ (p < 0.001). Vascular resistance was significantly lower in the pMJ35 group, compared with that in pGSVLacZ group, both in resting state (3.2 +/- 0.4 vs. 7.4 +/- 1.4 respectively, p < 0.05) and after the administration of nitroprusside. Capillary density (per mm2) was also superior in pMJ35 group (274 +/- 10) vs. p267 (204 +/- 9, p < 0.01) and LacZ (177 +/- 6, p < 0.001). CONCLUSION The paracrine effects of a secreted gene product may obviate the need for adjunctive vectors in strategies of arterial gene therapy.
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Couffinhal T, Kearney M, Sullivan A, Silver M, Tsurumi Y, Isner JM. Histochemical staining following LacZ gene transfer underestimates transfection efficiency. Hum Gene Ther 1997; 8:929-34. [PMID: 9195215 DOI: 10.1089/hum.1997.8.8-929] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Analysis of LacZ gene expression is conventionally inferred from blue staining that results from exposure of the transfected cells or tissue to the substrate 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside (X-Gal). Such histochemical staining reports not whether the gene product is present or absent, but where it is active. We investigated the hypothesis that identification of activity, as opposed to presence, of the enzyme underestimates gene expression following LacZ gene transfer. Under conditions optimized for in vitro histochemistry, up to 20% of cells stably transfected with nls-LacZ remained unstained by X-Gal. In contrast, immunostaining with a monoclonal or a polyclonal anti-beta-galactosidase (beta-Gal) antibody positively stained 99% of the cell nuclei. Following in vivo transfection of naked DNA encoding for nls-LacZ, X-Gal staining disclosed 2.7 +/- 1.7 positive nuclei per LacZ-transfected animal, or a transfection efficiency of 0.015%. In contrast, immunohistochemical staining disclosed 118 +/- 32.7 positive nuclei per transfected animal, yielding a transfection efficiency of 0.64% (p < 0.0001 versus X-Gal staining). Thus, 42.9 times more positive cells were detected by antibody than X-Gal staining. Finally, LacZ gene expression following intramuscular gene transfer with an adenoviral vector was observed in 7.6% of skeletal muscle cells assessed with X-Gal; anti-beta-Gal antibody identified 21.8% of cells as being successfully transfected (p < 0.0001). Thus, X-Gal histochemistry following gene transfer of constructs encoding LacZ may underestimate the anatomic extent of gene expression. The superior sensitivity of immunostaining suggests that anti-beta-Gal antibody represents the preferred analytical tool for light microscopic evaluation of LacZ gene transfer.
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Asahara T, Murohara T, Sullivan A, Silver M, van der Zee R, Li T, Witzenbichler B, Schatteman G, Isner JM. Isolation of putative progenitor endothelial cells for angiogenesis. Science 1997; 275:964-7. [PMID: 9020076 DOI: 10.1126/science.275.5302.964] [Citation(s) in RCA: 6224] [Impact Index Per Article: 230.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Putative endothelial cell (EC) progenitors or angioblasts were isolated from human peripheral blood by magnetic bead selection on the basis of cell surface antigen expression. In vitro, these cells differentiated into ECs. In animal models of ischemia, heterologous, homologous, and autologous EC progenitors incorporated into sites of active angiogenesis. These findings suggest that EC progenitors may be useful for augmenting collateral vessel growth to ischemic tissues (therapeutic angiogenesis) and for delivering anti- or pro-angiogenic agents, respectively, to sites of pathologic or utilitarian angiogenesis.
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MESH Headings
- Animals
- Antigens, CD34/analysis
- Biomarkers/analysis
- Cell Differentiation
- Cell Separation
- Cells, Cultured
- Endothelium, Vascular/chemistry
- Endothelium, Vascular/cytology
- Flow Cytometry
- Hindlimb/blood supply
- Humans
- Ischemia/physiopathology
- Mice
- Mice, Inbred C57BL
- Mice, Nude
- Mice, Transgenic
- Neovascularization, Physiologic
- Nitric Oxide Synthase/analysis
- Rabbits
- Receptor Protein-Tyrosine Kinases/analysis
- Receptors, Growth Factor/analysis
- Receptors, Vascular Endothelial Growth Factor
- Stem Cells/chemistry
- Stem Cells/cytology
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Fowden AL, Forhead AJ, Silver M, MacDonald AA. Glucose, lactate and oxygen metabolism in the fetal pig during late gestation. Exp Physiol 1997; 82:171-82. [PMID: 9023515 DOI: 10.1113/expphysiol.1997.sp004006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Using [U-14C]glucose tracer, rates of umbilical uptake, utilization and production of glucose, and of CO2 production from glucose carbon, were measured in seven chronically catheterized fetal pigs, when the sow was in the fed state, between 100 and 113 days of gestation (term, 114 +/- 2 days). At the same time, rates of umbilical O2 and lactate uptake were determined in all seven fetuses by the Fick principle. The mean fetal rates of umbilical glucose uptake, glucose utilization and CO2 production from glucose carbon were 38.4 +/- 4.2, 41.3 +/- 5.2 and 126.9 +/- 12.6 mumol min-1 (kg fetal body weight)-1, respectively (n = 7), No glucose production was therefore detected in the fetuses. Production of CO2 from glucose carbon accounted for 37.3 +/- 3.4% (n = 7) of the umbilical O2 uptake, which averaged 340 +/- 13 mumol min-1 kg-1 (n = 7). There was also significant umbilical lactate uptake in the fetal piglets when the sow was in the fed state (32.6 +/- 10.4 mumol min-1 kg-1, n = 7, P < 0.05). No significant changes in fetal glucose, O2 or lactate metabolism were observed with increasing age towards term. The fetal rates of glucose metabolism and of umbilical uptake of O2 and lactate were not correlated with fetal blood glucose level. Hence, glucose is used for both oxidative and non-oxidative metabolism in utero and is an important, although not the sole, source of carbon for metabolic processes in the fetal pig during late gestation.
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Houdusse A, Silver M, Cohen C. A model of Ca(2+)-free calmodulin binding to unconventional myosins reveals how calmodulin acts as a regulatory switch. Structure 1996; 4:1475-90. [PMID: 8994973 DOI: 10.1016/s0969-2126(96)00154-2] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND In contrast to conventional muscle myosins, where two different light chains (LCs) stabilize the elongated regulatory domain (RD) region of the head portion of the molecule, unconventional myosins are a diverse group of motors in which from one to six calmodulin (CaM) subunits are bound tandemly to the RD. In both cases, the heavy chains of the RDs have special sequences called "IQ motifs' to which the LCs or CaM bind. A previously puzzling aspect of certain unconventional myosins is their unusual mode of regulation, where activation of motility occurs at low levels of Ca2+. Although the atomic structure of the conventional muscle myosin RD has been determined, no crystallographic structure of the RD of an unconventional myosin is yet available. RESULTS We have constructed a model of vertebrate CaM bound to the first IQ motif present in the neck region of an unconventional myosin (chicken brush border myosin I), using strict binding rules derived from the crystal structure of the scallop RD. The model accounts for aspects of the regulation of many unconventional myosins where CaM is bound at low levels of Ca2+ and released or changed in conformation at high levels of Ca2+. The conformational changes as a function of Ca2+ depend not only on the precise sequence of the IQ motifs but also on the interactions between CaM molecules bound to adjacent sites on the myosin heavy chain. CONCLUSIONS According to our model, the full versatility of CaM binding to target peptides is displayed in the regulation of unconventional myosins. At low concentrations of Ca2+, CaM binds in a manner similar to the LCs of conventional myosins. At higher Ca2+ concentrations, CaM changes conformation and acts as a switch to regulate the activity of the unconventional myosin molecules.
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Bogden AE, LePage D, Zwicker S, Grant W, Silver M. Proliferative response of human prostate tumour xenografts to surgical trauma and the transurethral resection of the prostate controversy. Br J Cancer 1996; 73:73-8. [PMID: 8554987 PMCID: PMC2074276 DOI: 10.1038/bjc.1996.13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Transurethral resection of the prostate (TURP) as an excisional procedure involving multiple incisions into the prostate does not differentiate between palpably benign prostate tissue and microscopic foci of well-differentiated adenocarcinoma. The impact of TURP on the progression of such 'latent' or 'incidental' tumours unique to the prostate gland has been a focal point of a continuing controversy. In studies designed to develop preclinical evidence that would lend support to, or detract from, either side of the TURP controversy, surgical trauma-induced stimulation of in situ tumour growth was extended to include human prostate tumour tissue PC-3, DU-145 and H-1579, albeit as xenografts in athymic nude males. A significant proliferative response of prostate tumours implanted directly in, adjacent to, or distant from, a freshly induced surgical wound, could be inhibited by a somatostatin analogue (Lanreotide) applied topically to the surgical site. This preclinical model supports TURP as a risk factor for biopsy or therapeutic surgical intervention procedures in benign prostatic hypertrophy (BPH), a risk factor that increases with the stage of disease in undetected cancers. It also suggests a potential clinical benefit that might be derived by applying Lanreotide directly to the surgically traumatised genitourinary area by simple irrigation of the urethra and bladder during or shortly post TURP.
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Fowden AL, Silver M. Glucose and oxygen metabolism in the fetal foal during late gestation. THE AMERICAN JOURNAL OF PHYSIOLOGY 1995; 269:R1455-61. [PMID: 8594949 DOI: 10.1152/ajpregu.1995.269.6.r1455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
With the use of [U-14C]glucose tracer methodology, the rates of umbilical uptake, utilization, oxidation, and production of glucose were determined in nine chronically catheterized fetal foals in the fed state between 268 and 325 days of gestation (term approximately 335 days). At the same time, the rates of umbilical O2 and lactate uptake were measured in all nine fetuses by Fick principle. The mean fetal rates of umbilical glucose uptake, glucose utilization, and CO2 production from glucose carbon were 36.9 +/- 2.5, 36.4 +/- 1.7, and 117.7 +/- 17.4 mumol.min-1.kg fetal body wt-1, respectively (n = 9). Endogenous glucose production was therefore negligible in the fetal foal in the fed state. Production of CO2 from glucose carbon accounted for 40.9 +/- 6.5% of the umbilical O2 uptake, which averaged 292 +/- 15 mumol.min-1.kg-1 (n = 9). No significant changes in fetal glucose or O2 metabolism were observed with increasing gestational age. The rates of umbilical glucose uptake, glucose utilization, and CO2 production from glucose carbon (P < 0.01), but not the rate of umbilical O2 uptake (P > 0.05), were positively correlated with the fetal blood glucose level. There was a significant umbilical lactate uptake in the fetuses older than 290 days (12.3 +/- 4.1 mumol.min-1.kg-1, n = 5, P < 0.05) but not in the younger animals (6.2 +/- 9.6 mumol.min-1.kg-1, n = 4, P > 0.05). Hence, glucose is used for both oxidative and nonoxidative metabolism in utero and is a major, although not the sole, oxidative substrate in the fetal foal during late gestation.
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Diamond RJ, Goldfinger SM, Pollack D, Silver M. The role of psychiatrists in community mental health centers: a survey of job descriptions. Community Ment Health J 1995; 31:571-7; discussion 579-81. [PMID: 8608701 DOI: 10.1007/bf02189441] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
There is little data about the role of psychiatrists within CMHCs. To gain perspective on this issue, job descriptions for medical directors and staff psychiatrists were collected from 214 CMHCs. The data demonstrated that most CMHCs want fully trained psychiatrists involved in a variety of activities in addition to prescribing medication. Policy development was specifically included as part of the medical director's job for 69% of the CMHCs, and 50% mentioned training as part of the staff psychiatrist's job. Although job descriptions may not accurately reflect the actual roles of the psychiatrist in all cases, these data suggest that CMHCs support a multifaceted role for their psychiatrists.
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Han X, Rossdale PD, Ousey J, Holdstock N, Allen WR, Silver M, Fowden AL, McGladdery AJ, Labrie F, Belanger A. Localisation of 15-hydroxy prostaglandin dehydrogenase (PGDH) and steroidogenic enzymes in the equine placenta. Equine Vet J 1995; 27:334-9. [PMID: 8654347 DOI: 10.1111/j.2042-3306.1995.tb04067.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
15-hydroxy prostaglandin dehydrogenase (PGDH) is the critical enzyme that determines metabolism of primary prostaglandins. Its expression is determined in part by steroid hormones, particularly progesterone, formed from delta(5) steroids through 3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity. To assess whether the regulation of PGDH might occur in a paracrine, autocrine or intracrine fashion, we used immunohistochemistry (IHC) to determine the localisation of key steroidogenic enzymes in the equine placenta and compared these patterns to the distribution of immunoreactive (IR-) PGDH. Placental tissue was obtained from pony or Thoroughbred mares at about Days 150, 250-280 and >300 of pregnancy (term 320 to 360 days; n=5-8 each group). IR-PGDH, 3beta-HSD, cholesterol side chain cleavage enzyme (P450(scc)) and 17-hydroxylase/lyase (P450(C17)) were localised using specific antibodies and the avidin-biotin peroxidase technique and visualised using diaminobenzidine as substrate. IR-P450(scc) was present in trophoblast cells, but not in maternal tissues of the microcotyledons. In contrast, at Days 150 and 280, IR-PGDH was present in maternal epithelial and interstitial cells in the microcotyledons, but was not detected in trophoblast epithelium, chorioallantois or endometrial glands. After Day 300, IR-PGDH was present in the maternal epithelium and interstitial cells of the placenta and it was also present in trophoblast cells in some specimens.
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