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Fraga S, Ramos E, Dias S, Barros H. Physical fighting among school-going Portuguese adolescents: social and behavioural correlates. Prev Med 2011; 52:401-4. [PMID: 21371501 DOI: 10.1016/j.ypmed.2011.02.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 02/15/2011] [Accepted: 02/21/2011] [Indexed: 10/18/2022]
Abstract
OBJECTIVE The purpose of this study was to estimate the frequency and to assess the determinants of physical fighting among Portuguese school-going adolescents. METHODS A cross-sectional evaluation of urban adolescents born in 1990 and enrolled in public and private schools of Porto was performed in 2007. We identified 3161 17-year-old eligible adolescents and 73.3% accepted to participate. Information was collected using a self-administered questionnaire assessing socio-demographic, behavioural, family and health-related characteristics. The magnitude of the associations between those characteristics and physical fighting was estimated using logistic regression. RESULTS Overall, 33.8% of adolescents (48.6% of boys and 20.1% of girls; p < 0.001) engaged in a physical fight during the previous 12 months. The school premises were the most frequently reported setting where fights occurred (girls--41.2% and boys--46.7%, p = 0.179). After adjustment, and in both genders, we found statistically significant associations between physical fighting and grade retention, smoking, drinking and age at first sexual intercourse. CONCLUSION Physical fighting among school-going adolescents is frequent, tends to occur at school premises and to cluster with other well recognized adverse health behaviours.
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Queiros C, Dias S, Marques A. Burnout and engagement in portuguese nurses working with mental illness. Eur Psychiatry 2011. [DOI: 10.1016/s0924-9338(11)73303-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
IntroductionIn their activities nurses deals with pain, suffering people and deficient work conditions related with physical aspects, emotional relationships within the team or difficulty to adapt to new rules. Working with mental ill individuals increase the demands and some professionals became emotional exhausted, stressed and feel in burnout, whereas others became motivated and engaged. According to recent literature, engagement can protect from burnout, helping professionals to efficiently cope with stressful situations (Schaufeli et al., 2002).AimsIdentify the levels of burnout and engagement of nurses working with mental illness.MethodsData were collected using a translation from Maslach Burnout Inventory (Maslach & Jackson, 1997) and Utrech Work Enthusiasm Scale (Schaufeli & Bakker, 2003), applied to 110 portuguese nurses working with mental illness. The sample was composed by 21% male and 79% female; mean age 37.7 years.ResultsOur nurses don’t feel burnout, showing low emotional exhaustion (M = 2.3 in a Likert scale 0–6 points), lowest cynism (M = 0.97) and higher professional efficacy (M = 4.5). They feel engaged with work, showing higher dedication (M = 4.3), vigor (M = 3.99) and absorption (M = 3.7). Some differences were found, with males showing higher cynism than females. Burnout was negatively correlated with engagement.ConclusionsDespite lower results of burnout in our sample, nursing is a professional activity that elicits stress, making professionals vulnerable to burnout, especially when they work with patients with special demands such us mentally ill people. However, engagement appear as a protective factor to feel burnout, allowing professionals to be dedicated and absorbed by their activity.
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Dias S, Gama A, Horta R. Avaliação dos cuidados de saúde: percepções de mulheres imigrantes em Portugal. REVISTA BRASILEIRA DE SAÚDE MATERNO INFANTIL 2010. [DOI: 10.1590/s1519-38292010000500004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJETIVOS: descrever práticas relacionadas com a procura de cuidados de saúde e percepções relativamente a aspectos da utilização dos serviços de saúde por parte de uma população de mulheres imigrantes a residir em Portugal. MÉTODOS: em 2009 foi realizado um estudo transversal na área metropolitana de Lisboa onde foi aplicado um inquérito por questionário a uma amostra de 703 mulheres imigrantes. O questionário incluiu itens para caracterização sóciodemográfica e sobre práticas relacionadas com a procura de cuidados de saúde e percepções das participantes quanto à utilização dos serviços. Realizou-se uma análise descritiva das variáveis em estudo. RESULTADOS: a grande maioria das participantes (82.4%) reporta já ter utilizado o Serviço Nacional de Saúde (SNS), mais frequentemente as africanas (94,5%) e do Leste Europeu (87,2%) do que as brasileiras (66.8%). Cerca de 60% das inquiridas revela estar satisfeita ou muito satisfeita com os serviços, mais frequentemente as africanas (77%) do que as brasileiras (49,7%) e do Leste Europeu (43,4%). Os grupos de participantes apontam diferentes obstáculos para a utilização dos serviços de saúde, entre os quais aspectos relacionados com a condição de ser imigrante, a interação com os profissionais de saúde e os serviços. CONCLUSÕES: as diferenças nas percepções dos grupos de imigrantes sobre os serviços e profissionais refletem a importância de desenvolver práticas avaliativas que identifiquem necessidades de intervenção. Tal conhecimento pode contribuir para melhor adequar a prestação de cuidados de saúde às especificidades dos grupos de imigrantes.
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Dias S, Gama A, Rocha C. Perspectives of African and Brazilian immigrant women on sexual and reproductive health. EUR J CONTRACEP REPR 2010; 15:255-63. [DOI: 10.3109/13625187.2010.497232] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Manarte LF, Dias S, Góis C, Boavida JM. Independent factors associated with depression in type 1 diabetes mellitus. Acta Diabetol 2010; 47:201-7. [PMID: 19300897 DOI: 10.1007/s00592-009-0110-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2008] [Accepted: 02/26/2009] [Indexed: 10/21/2022]
Abstract
Diabetes has been associated with depression since Thomas Willis' work in 1684 (Rubin and Peyrot in Diabetes Metab Rev 18:173-175, 2002). The aim of this study is to identify social and clinical factors independently associated with depression in individuals with type 1 diabetes. We carried out a descriptive transversal study with 110 type 1 diabetes patients, administered a questionnaire and obtained demographical and diabetes-related data (number of years from diagnosis, initial admission at diagnosis, glycated hemoglobin, number of complications, insulin dose, number of insulin injections per day, admission for ketoacidosis or hypoglycemia at diagnosis, and specific diabetes complications such as nephropathy, retinopathy, peripheral neuropathy, coronariopathy, and amputation). Depressive symptoms were quantified using the Hamilton Score. We used T tests to investigate potential relations between the covariates and depression (Hamilton score). We concluded the following: as few as 10% of our patients had glycated hemoglobin under 7%; women had more symptoms of depression, and there are four independent factors associated with depression in individuals with type 1 diabetes mellitus: age, Graffar score, admission for ketoacidosis, and insulin dose.
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Dias S, Welton NJ, Caldwell DM, Ades AE. Checking consistency in mixed treatment comparison meta-analysis. Stat Med 2010; 29:932-44. [PMID: 20213715 DOI: 10.1002/sim.3767] [Citation(s) in RCA: 1530] [Impact Index Per Article: 109.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Pooling of direct and indirect evidence from randomized trials, known as mixed treatment comparisons (MTC), is becoming increasingly common in the clinical literature. MTC allows coherent judgements on which of the several treatments is the most effective and produces estimates of the relative effects of each treatment compared with every other treatment in a network.We introduce two methods for checking consistency of direct and indirect evidence. The first method (back-calculation) infers the contribution of indirect evidence from the direct evidence and the output of an MTC analysis and is useful when the only available data consist of pooled summaries of the pairwise contrasts. The second more general, but computationally intensive, method is based on 'node-splitting' which separates evidence on a particular comparison (node) into 'direct' and 'indirect' and can be applied to networks where trial-level data are available. Methods are illustrated with examples from the literature. We take a hierarchical Bayesian approach to MTC implemented using WinBUGS and R.We show that both methods are useful in identifying potential inconsistencies in different types of network and that they illustrate how the direct and indirect evidence combine to produce the posterior MTC estimates of relative treatment effects. This allows users to understand how MTC synthesis is pooling the data, and what is 'driving' the final estimates.We end with some considerations on the modelling assumptions being made, the problems with the extension of the back-calculation method to trial-level data and discuss our methods in the context of the existing literature.
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Andrade M, Khoury H, Borrás C, Dias S, Barros V. SU-GG-I-79: Image Quality, Organ Doses and Risks of Computed Tomography Exams in Pernambuco, Brazil. Med Phys 2010. [DOI: 10.1118/1.3468112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Costa A, Casalou C, Caiado F, Igreja C, Dias S. 713 miR-210 is associated to endothelial cell fusion. EJC Suppl 2010. [DOI: 10.1016/s1359-6349(10)71510-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Dias S, Gama A, Rocha C. Immigrant women’s perceptions and experiences of health care services: Insights from a focus group study. J Public Health (Oxf) 2010. [DOI: 10.1007/s10389-010-0326-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Carvalho T, Elias AP, Nunes T, Peleteiro MC, Dias S. Chemo-angiogenic profile of bovine urinary bladder tumors distinguishes urothelial carcinomas from hemangiosarcomas. Vet Immunol Immunopathol 2007; 121:344-58. [PMID: 18022698 DOI: 10.1016/j.vetimm.2007.09.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2007] [Revised: 09/24/2007] [Accepted: 09/26/2007] [Indexed: 01/27/2023]
Abstract
Angiogenesis and inflammation are two processes regulated by numerous common molecular mechanisms. Inflammation can stimulate angiogenesis, and angiogenesis can facilitate inflammation; both mechanisms have been shown to be involved in carcinogenesis. With this study we sought to gain an understanding of the molecular mechanisms involved in tumor angiogenesis and inflammation in urinary bladder tumors. Tumor specimens were collected at slaughter from Friesian cows chronically exposed to bracken fern. Bracken chronic toxicity is characterized by the presence of multiple mixed tumors in the bladder, being reported throughout the world under the designation of bovine enzootic hematuria. We conducted molecular analyses of angiogenic factors and chemokine production by real-time RT-PCR, and also assessed microvessel density (MVD), microvessel pericyte coverage index (MPI) to reveal mature vessels, the extent of tumor-infiltrating leukocytes (TILk) and tumor cell apoptosis and proliferation in both epithelial and endothelial-derived bovine urinary bladder tumors. We defined a profile of chemokines/chemokine receptors (Mip1beta, CCR1) and angiogenesis-related factors (VEGF, VEGFR2) that allow distinguishing between urothelial carcinomas (epithelial origin) and hemangiosarcomas (endothelial origin). Taken together, our data reveals previously unrecognized paracrine and autocrine chemo-angiogenic loops in the context of bovine urinary bladder tumorigenesis.
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Azevedo NF, Almeida C, Cerqueira L, Dias S, Keevil CW, Vieira MJ. Coccoid form of Helicobacter pylori as a morphological manifestation of cell adaptation to the environment. Appl Environ Microbiol 2007; 73:3423-7. [PMID: 17400788 PMCID: PMC1907093 DOI: 10.1128/aem.00047-07] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
After characterization of preferred conditions for Helicobacter pylori survival in the sessile state, it was observed that the bacterium transforms from spiral to coccoid under mild circumstances, whereas under extreme ones it is unable to undergo shape modification. This strongly supports the view that transformation into the coccoid form is an active, biologically led process, switched on by the bacterium as a protection mechanism.
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Casalou C, Fragoso R, Nunes JFM, Dias S. VEGF/PLGF induces leukemia cell migration via P38/ERK1/2 kinase pathway, resulting in Rho GTPases activation and caveolae formation. Leukemia 2007; 21:1590-4. [PMID: 17392818 DOI: 10.1038/sj.leu.2404668] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sallam HN, Garcia-Velasco JA, Dias S, Arici A. Long-term pituitary down-regulation before in vitro fertilization (IVF) for women with endometriosis. Cochrane Database Syst Rev 2006; 2006:CD004635. [PMID: 16437491 PMCID: PMC8195082 DOI: 10.1002/14651858.cd004635.pub2] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Women with endometriosis who are treated with in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) have a lower pregnancy rate compared to women with tubal factor infertility. It has been suggested that the administration of gonadotrophin releasing hormone (GnRH) agonists for a few months prior to IVF or ICSI increases the pregnancy rate. OBJECTIVES To determine the effectiveness of administering GnRH agonists for three to six months prior to IVF or ICSI in women with endometriosis. SEARCH STRATEGY We used computer searches of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, the National Research Register (NRR) and the MDSG Specialised Register of controlled trials. We handsearched proceedings of annual meetings of the American Society for Reproductive Medicine (ASRM) and the European Society for Human Reproduction and Embryology (ESHRE). We reviewed lists of references in original research and review articles. We contacted experts in various countries to identify unpublished trials. SELECTION CRITERIA We included randomised controlled trials using any GnRH agonist prior to IVF or ICSI to treat women with any degree of endometriosis diagnosed by laparoscopy or laparotomy DATA COLLECTION AND ANALYSIS Two independent review authors abstracted data (HNS and JGV). We sent e-mails to investigators to seek additional information. We assessed the validity of each study using the methods suggested in the Cochrane Handbook. The data were checked by the third review author (SD) and any disagreement was resolved by arbitration with the fourth review author (AA). We generated 2 x 2 tables for principal outcome measures. The Peto-modified Mantel-Haenszel technique was used to calculate odds ratios (OR) and assess statistical heterogeneity between studies. MAIN RESULTS Three randomised controlled trials (with 165 women) were included. The live birth rate per woman was significantly higher in women receiving the GnRH agonist compared to the control group (OR 9.19, 95% CI 1.08 to 78.22). However, this was based on one trial reporting "viable pregnancy" only. The clinical pregnancy rate per woman was also significantly higher (three studies: OR 4.28, 95% CI 2.00 to 9.15). The information on miscarriage rates came from two trials with high heterogeneity and, therefore, results of the meta-analysis were doubtful. The included studies provided insufficient data to investigate the effects of administration of GnRH agonists on multiple or ectopic pregnancies, fetal abnormalities or other complications. AUTHORS' CONCLUSIONS The administration of GnRH agonists for a period of three to six months prior to IVF or ICSI in women with endometriosis increases the odds of clinical pregnancy by fourfold. Data regarding adverse effects of this therapy on the mother or fetus are not available at present.
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Pietrass T, Dewald JL, Clewett CFM, Tierney D, Ellis AV, Dias S, Alvarado A, Sandoval L, Tai S, Curran SA. Electron spin resonance and raman scattering spectroscopy of multi-walled carbon nanotubes: a function of acid treatment. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2006; 6:135-40. [PMID: 16573084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We compare the fundamental transport mechanism in multi-walled carbon nanotubes (MWNTs) by means of electron spin resonance (ESR) and Raman spectroscopy as a function of acid treatment. The ESR and Raman results show that the acid treatment reduces the density of states at the Fermi level. Defects introduced through the acid treatment move the Fermi level closer to the K points in the valence band, and consequently conduction is reduced. These defects are identified as Stone-Wales type from the Raman results.
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Botelho M, Amendoeira I, Diamond J, Dias S, Schmitt F. Breast tumors induce the recruitment of AC133+KDR+ endothelial precursor cells mobilized by plasma vascular endothelial growth factor. Breast Cancer Res 2005. [PMCID: PMC4233608 DOI: 10.1186/bcr1187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Moldenhauer A, Nociari MM, Dias S, Lalezari P, Moore MAS. Optimized culture conditions for the generation of dendritic cells from peripheral blood monocytes. Vox Sang 2003; 84:228-36. [PMID: 12670372 DOI: 10.1046/j.1423-0410.2003.00283.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND AND OBJECTIVES Dendritic cells (DCs) are promising adjuvants for clinical immunotherapy, but they are scantily distributed. Therefore, numerous in vitro methods have been developed to expand these cells while maintaining their normal functions. Current culture systems generally require the use of fetal bovine serum (FBS)-supplemented media in order to attain DCs with high immunostimulatory activity. However, the presence of exogenous animal proteins sets limits for their use in clinical trials. The purpose of this study was to establish a simple, efficient and FBS-free method for the generation of human DCs for clinical application. MATERIALS AND METHODS We compared monocyte-derived DCs generated in a standard FBS-supplemented medium vs. DCs generated in an autologous plasma (AutoPl)-supplemented medium, with regard to their yield, function and longevity. Peripheral blood monocytes were isolated from buffy coats by two consecutive 2-h adherence steps in tissue culture flasks. The adherent cells were differentiated into DCs within 2 weeks by adding granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-4 (IL-4), c-kit ligand and tumour necrosis factor-alpha (TNF-alpha). Every 2-3 days, the cells in suspension were analysed for their immunophenotype and apoptosis rate by flow cytometry. Their function was demonstrated by their allostimulatory and migratory capacity, as well as by their proteolytic activity. RESULTS We show that more than 30 x 10(6) DCs can be achieved per unit of buffy coat using either AutoPl- or FBS-supplemented media. The purity of the DCs was 53.4% and 65% (P > 0.05) in AutoPl- and FBS-based medium, respectively. DCs grown in AutoPl media showed a CD80high CD83+ CD86high CD14neg HLA-DR+ CD1aneg phenotype, while FBS-generated DCs exhibited a CD80high CD83+ CD86high CD14neg HLA-DR+ CD1ahigh phenotype. The apoptosis rate in both culture conditions increased from 10% to 25% over 1 week. AutoPl-generated DCs were shown to be equally strong stimulators for proliferation of allogeneic T lymphocytes as FBS-generated DCs. In addition, the capacity to migrate in response to macrophage inflammatory protein-1alpha (MIP-1alpha) and stromal-cell-derived factor 1alpha (SDF-1alpha) was similar in both groups, whereas the response to MIP-3beta was reduced in AutoPl-derived cells. Zymography analysis of supernatants from 5-day-old cultures demonstrated that AutoPl-generated DCs produced higher amounts of matrix metalloproteinases, suggesting that they have an enhanced capability to traffic through peripheral tissues. CONCLUSIONS Our findings indicate that plastic-adherent peripheral blood cells, when cultured with GM-CSF, IL-4, c-kit-ligand and TNF-alpha in autologous human plasma-supplemented media, are a potent source of functional DCS that may be of value for human therapy.
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Zhu Z, Hattori K, Zhang H, Jimenez X, Ludwig DL, Dias S, Kussie P, Koo H, Kim HJ, Lu D, Liu M, Tejada R, Friedrich M, Bohlen P, Witte L, Rafii S. Inhibition of human leukemia in an animal model with human antibodies directed against vascular endothelial growth factor receptor 2. Correlation between antibody affinity and biological activity. Leukemia 2003; 17:604-11. [PMID: 12646950 DOI: 10.1038/sj.leu.2402831] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Vascular endothelial growth factor (VEGF) and its receptors (VEGFR) have been implicated in promoting solid tumor growth and metastasis via stimulating tumor-associated angiogenesis. We recently showed that certain 'liquid' tumors such as leukemia not only produce VEGF, but also express functional VEGFR, resulting in an autocrine loop for tumor growth and propagation. A chimeric anti-VEGFR2 (or kinase insert domain-containing receptor, KDR) antibody, IMC-1C11, was shown to be able to inhibit VEGF-induced proliferation of human leukemia cells in vitro, and to prolong survival of nonobese diabetic-severe combined immune deficient (NOD-SCID) mice inoculated with human leukemia cells. Here we produced two fully human anti-KDR antibodies (IgG1), IMC-2C6 and IMC-1121, from Fab fragments originally isolated from a large antibody phage display library. These antibodies bind specifically to KDR with high affinities: 50 and 200 pM for IMC-1121 and IMC-2C6, respectively, as compared to 270 pM for IMC-1C11. Like IMC-1C11, both human antibodies block VEGF/KDR interaction with an IC(50) of approximately 1 nM, but IMC-1121 is a more potent inhibitor to VEGF-stimulated proliferation of human endothelial cells. These anti-KDR antibodies strongly inhibited VEGF-induced migration of human leukemia cells in vitro, and when administered in vivo, significantly prolonged survival of NOD-SCID mice inoculated with human leukemia cells. It is noteworthy that the mice treated with antibody of the highest affinity, IMC-1121, survived the longest period of time, followed by mice treated with IMC-2C6 and IMC-1C11. Taken together, our data suggest that anti-KDR antibodies may have broad applications in the treatment of both solid tumors and leukemia. It further underscores the efforts to identify antibodies of high affinity for enhanced antiangiogenic and antitumor activities.
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Lane WJ, Hattori K, Dias S, Peerschke EI, Moore MA, Blanset DL, Lang PC, Petrone M, Rafii S. Anagrelide metabolite induces thrombocytopenia in mice by inhibiting megakaryocyte maturation without inducing platelet aggregation. Exp Hematol 2001; 29:1417-24. [PMID: 11750100 DOI: 10.1016/s0301-472x(01)00742-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The mechanism for anagrelide's potent platelet lowering activity in human subjects is not well defined. Studies related to anagrelide function have been hampered by its lack of activity in nonhuman primates and water insolubility. In an effort to define the mechanism whereby anagrelide exerts its therapeutic effect, we identified a water-soluble metabolite (anagrelide.met). The availability of anagrelide.met allowed, for the first time, parallel in vitro and in vivo animal studies centered on the mechanisms by which anagrelide lowers platelet levels. MATERIALS AND METHODS The effects of anagrelide.met on proliferation and maturation of mega-karyocytes (MKs) as well as platelet production were studied both in vitro and in vivo. RESULTS Anagrelide.met is capable of blocking in vitro MK migration by 20% to 40%. At 100 ng/mL, anagrelide.met selectively blocked in vitro MK maturation, resulting in a 50% decrease in the total number of CD41a(+) MKs, corresponding with a 30% decrease in MK ploidy by day 10 and a 60% decrease by day 20. Daily intraperitoneal injections of anagrelide.met 100 microg into BALB/c mice was sufficient to significantly decrease platelet counts within 24 to 48 hours, stabilizing to 40 to 50% of normal levels by day 5. This was associated with a 45% decrease in the number of developing MKs and an increase in thrombopoietin levels. Anagrelide.met did not alter WBC counts, hematocrit, or bleeding time, or lead to any apparent signs of toxicity. Furthermore, unlike the parent anagrelide compound, anagrelide.met did not inhibit ADP-induced platelet aggregation even at high concentrations (10 microg/mL). CONCLUSIONS We describe a cross-species reactive anagrelide metabolite that selectively inhibits MK maturation and migration, lowering platelet levels without influencing platelet aggregation.
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Lyden D, Hattori K, Dias S, Costa C, Blaikie P, Butros L, Chadburn A, Heissig B, Marks W, Witte L, Wu Y, Hicklin D, Zhu Z, Hackett NR, Crystal RG, Moore MA, Hajjar KA, Manova K, Benezra R, Rafii S. Impaired recruitment of bone-marrow-derived endothelial and hematopoietic precursor cells blocks tumor angiogenesis and growth. Nat Med 2001; 7:1194-201. [PMID: 11689883 DOI: 10.1038/nm1101-1194] [Citation(s) in RCA: 1511] [Impact Index Per Article: 65.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The role of bone marrow (BM)-derived precursor cells in tumor angiogenesis is not known. We demonstrate here that tumor angiogenesis is associated with recruitment of hematopoietic and circulating endothelial precursor cells (CEPs). We used the angiogenic defective, tumor resistant Id-mutant mice to show that transplantation of wild-type BM or vascular endothelial growth factor (VEGF)-mobilized stem cells restore tumor angiogenesis and growth. We detected donor-derived CEPs throughout the neovessels of tumors and Matrigel-plugs in an Id1+/-Id3-/- host, which were associated with VEGF-receptor-1-positive (VEGFR1+) myeloid cells. The angiogenic defect in Id-mutant mice was due to impaired VEGF-driven mobilization of VEGFR2+ CEPs and impaired proliferation and incorporation of VEGFR1+ cells. Although targeting of either VEGFR1 or VEGFR2 alone partially blocks the growth of tumors, inhibition of both VEGFR1 and VEGFR2 was necessary to completely ablate tumor growth. These data demonstrate that recruitment of VEGF-responsive BM-derived precursors is necessary and sufficient for tumor angiogenesis and suggest new clinical strategies to block tumor growth.
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Dias S, Choy M, Rafii S. The role of CXC chemokines in the regulation of tumor angiogenesis. Cancer Invest 2001; 19:732-8. [PMID: 11577814 DOI: 10.1081/cnv-100106148] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Dias S, Hattori K, Heissig B, Zhu Z, Wu Y, Witte L, Hicklin DJ, Tateno M, Bohlen P, Moore MA, Rafii S. Inhibition of both paracrine and autocrine VEGF/ VEGFR-2 signaling pathways is essential to induce long-term remission of xenotransplanted human leukemias. Proc Natl Acad Sci U S A 2001; 98:10857-62. [PMID: 11553814 PMCID: PMC58564 DOI: 10.1073/pnas.191117498] [Citation(s) in RCA: 223] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Antiangiogenic agents block the effects of tumor-derived angiogenic factors (paracrine factors), such as vascular endothelial growth factor (VEGF), on endothelial cells (EC), inhibiting the growth of solid tumors. However, whether inhibition of angiogenesis also may play a role in liquid tumors is not well established. We recently have shown that certain leukemias not only produce VEGF but also selectively express functional VEGF receptors (VEGFRs), such as VEGFR-2 (Flk-1, KDR) and VEGFR1 (Flt1), resulting in the generation of an autocrine loop. Here, we examined the relative contribution of paracrine (EC-dependent) and autocrine (EC-independent) VEGF/VEGFR signaling pathways, by using a human leukemia model, where autocrine and paracrine VEGF/VEGFR loops could be selectively inhibited by neutralizing mAbs specific for murine EC (paracrine pathway) or human tumor (autocrine) VEGFRs. Blocking either the paracrine or the autocrine VEGF/VEGFR-2 pathway delayed leukemic growth and engraftment in vivo, but failed to cure inoculated mice. Long-term remission with no evidence of disease was achieved only if mice were treated with mAbs against both murine and human VEGFR-2, whereas mAbs against human or murine VEGFR-1 had no effect on mice survival. Therefore, effective antiangiogenic therapies to treat VEGF-producing, VEGFR-expressing leukemias may require blocking both paracrine and autocrine VEGF/VEGFR-2 angiogenic loops to achieve remission and long-term cure.
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MESH Headings
- Animals
- Autocrine Communication
- Cell Division
- Cells, Cultured
- Coculture Techniques
- Endothelial Growth Factors/metabolism
- Endothelium, Vascular/cytology
- Endothelium, Vascular/metabolism
- HL-60 Cells
- Humans
- Leukemia, Promyelocytic, Acute/metabolism
- Leukemia, Promyelocytic, Acute/physiopathology
- Lymphokines/metabolism
- Mice
- Neoplasm Invasiveness
- Neoplasm Transplantation
- Neoplasms, Experimental/metabolism
- Neoplasms, Experimental/physiopathology
- Neovascularization, Pathologic/physiopathology
- Paracrine Communication
- Receptor Protein-Tyrosine Kinases/metabolism
- Receptors, Growth Factor/metabolism
- Receptors, Vascular Endothelial Growth Factor
- Signal Transduction
- Time Factors
- Transplantation, Heterologous
- Vascular Endothelial Growth Factor A
- Vascular Endothelial Growth Factors
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173
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Franco S, MacKenzie KL, Dias S, Alvarez S, Rafii S, Moore MA. Clonal variation in phenotype and life span of human embryonic fibroblasts (MRC-5) transduced with the catalytic component of telomerase (hTERT). Exp Cell Res 2001; 268:14-25. [PMID: 11461114 DOI: 10.1006/excr.2001.5264] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Expression of telomerase (hTERT) in certain cell types has been shown to extend cellular life span without malignant transformation. We studied the phenotype of 26 telomerase-transduced fibroblast clones (TTFC) generated from a mass culture of hTERT retrovirally transduced MRC-5 cells. About two-thirds of the transduced clones senesced at the expected time or shortly thereafter, despite high levels of expression of telomerase and telomere length maintenance. The remaining one-third of the clones were "immortalized" (followed for over 200 cumulative population doublings). All clones maintained a nontransformed phenotype: contact inhibition, anchorage dependency, lack of tumor formation in nude mice, dose dependency to serum and growth factors, low expression of a matrix metalloproteinase associated with metastatic invasion (MMP-9) and high expression of its inhibitor TIMP-1, and no cytogenetic abnormalities by G-banding. In addition, fibroblast-specific biological parameters, such as colony size, production of collagenase, and response to MMC and gamma radiation were tightly regulated at the clonal and subclonal levels.
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174
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Moore MA, Hattori K, Heissig B, Shieh JH, Dias S, Crystal RG, Rafii S. Mobilization of endothelial and hematopoietic stem and progenitor cells by adenovector-mediated elevation of serum levels of SDF-1, VEGF, and angiopoietin-1. Ann N Y Acad Sci 2001; 938:36-45; discussion 45-7. [PMID: 11458524 DOI: 10.1111/j.1749-6632.2001.tb03572.x] [Citation(s) in RCA: 205] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The chemokine stroma-derived factor-1 (SDF-1) is produced within the bone marrow and mediates chemokinesis and chemotaxis on a variety of cell types that express the CXCR4 receptor. SDF-1-responsive cell types include monocytes and macrophages, B and T lymphocytes, platelets and megakaryocytes, and CD34+ cells, including both hematopoietic progenitors and stem cells. We have used intravenous injection of a replication-incompetent adenovector expressing the SDF-1 gene to elevate serum levels of SDF-1 in Balb/c and SCID mice. Within 3 to 5 days there was a marked leukocytosis, predominantly involving monocytes, and a three-fold increase in platelets. In addition, AdSDF-1 mobilized CFU-GM, CFU-s, and cells with long-term repopulating potential. We have identified a bone marrow-derived, circulating endothelial stem cell characterized by expression of the VEGFR2 (Flk-1/KDR). This cell exhibits a chemotactic and chemokinetic response to SDF-1 and VEGF. We have elevated serum levels of VEGF165 using intravenous adenovector gene delivery and compared this to an adenovector expressing angiopoietin-1 alone or in combination with VEGF. VEGF elevation was associated with rapid mobilization of hematopoietic stem and progenitor cells and a population of Flk-1-positive endothelial progenitors. In contrast angiopoietin induced a delayed mobilization of endothelial and hematopoietic progenitors. The combination of VEGF and angiopoietin produced a more prolonged elevation of these progenitors in the circulation with increased proliferation of capillaries and expansion of sinusoidal spaces in the marrow.
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175
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Rafii S, Dias S, Meeus S, Hattori K, Ramachandran R, Feuerback F, Worgall S, Hackett NR, Crystal RG. Infection of Endothelium With E1
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E4
+
, but Not E1
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E4
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, Adenovirus Gene Transfer Vectors Enhances Leukocyte Adhesion and Migration by Modulation of ICAM-1, VCAM-1, CD34, and Chemokine Expression. Circ Res 2001; 88:903-10. [PMID: 11348999 DOI: 10.1161/hh0901.089884] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Abstract
—Intravascular introduction of replication-deficient adenoviral vectors (Advectors) provides an ideal model of delivery of transgenes for the treatment of various vascular abnormalities. On the basis of the knowledge that Advectors can induce inflammatory responses after intravascular administration, we speculated that cellular activation by Advector infection could directly modulate the endothelial cell (EC) adhesion molecule/chemokine expression repertoire. Infection of human umbilical vein ECs or bone marrow microvascular ECs with an E1
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E4
+
Advector resulted in the upregulation of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and CD34, but not E-selectin, P-selectin, CD36, CD13, CD44, HLA-DR or PECAM. Upregulation of ICAM-1, VCAM-1, and CD34 was apparent 12 hours after infection and persisted for weeks after infection. Selective induction of adhesion molecules was mediated by the presence of the E4 gene in the Advector, because infection of ECs with an E1
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E4
−
Advector had no effect on adhesion molecule expression. ECs infected with E1
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E4
+
Advector, but not those infected with E1
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E4
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Advector, supported the adhesion of leukocytes. Monoclonal antibodies to ICAM-1 and VCAM-1 inhibited adhesion of leukocytes to E1
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E4
+
-infected ECs. Infection of the ECs with E1
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E4
+
Advector, but not E1
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E4
−
Advector, resulted in downregulation of expression of chemocytokines, including interleukin-8, MCP-1, RANTES, and GM-CSF. Nonetheless, a large number of leukocytes migrated through ECs infected with E1
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E4
+
, but not those infected with E1
−
E4
l−
, in response to exogenous chemokines. These results demonstrate that infection of ECs with E1
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E4
+
Advectors, but not E1
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E4
−
Advectors, may directly augment inflammatory responses by upregulating expression of adhesion molecules and enhancing migration through Advector-infected ECs and suggest that E1
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E4
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Advectors may be a better choice for gene-transfer strategies directed to the ECs.
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