Health care for irregular migrants: pragmatism across Europe: a qualitative study

BACKGROUND

Health services in Europe face the challenge of delivering care to a heterogeneous group of irregular migrants (IM). There is little empirical evidence on how health professionals cope with this challenge. This study explores the experiences of health professionals providing care to IM in three types of health care service across 16 European countries.

RESULTS

Semi-structured interviews were conducted with health professionals in 144 primary care services, 48 mental health services, and 48 Accident & Emergency departments (total n = 240). Although legal health care entitlement for IM varies across countries, health professionals reported facing similar issues when caring for IM. These issues include access problems, limited communication, and associated legal complications. Differences in the experiences with IM across the three types of services were also explored. Respondents from Accident & Emergency departments reported less of a difference between the care for IM patients and patients in a regular situation than did respondents from primary care and mental health services. Primary care services and mental health services were more concerned with language barriers than Accident & Emergency departments. Notifying the authorities was an uncommon practice, even in countries where health professionals are required to do this.

CONCLUSIONS

The needs of IM patients and the values of the staff appear to be as important as the national legal framework, with staff in different European countries adopting a similar pragmatic approach to delivering health care to IM. While legislation might help to improve health care for IM, more appropriate organisation and local flexibility are equally important, especially for improving access and care pathways.

Does interview setting influence disclosure of violence? A study in elderly

BACKGROUND

Violence is a very sensitive research topic and interview's setting might influence the participation rate and response accuracy. We aimed to evaluate such effect when assessing the prevalence of different types of violence in a sample of urban elderly by comparing those interviewed at home with those assessed at the research office.

METHODS

Study subjects were members of a cohort of urban dwellers previously assembled using random digit dialling. The initial 450 individuals aged 60-84 years old were invited to participate in the present study, after being randomly allocated into two groups: 150 for being scheduled to research office interview and 300 to home interview. Both groups allocated were similar regarding gender, age, education, marital status and behavioural characteristics such as smoking and drinking alcohol. Information was obtained by face-to-face standardised interviews.

RESULTS

We obtained a participation rate of 67.0% in the group allocated to home interview and 70.7% in the other group (P = 0.431). No statistically significant differences were found when prevalence of violence during the previous year was compared according to the interview setting (physical 2.5 versus 1.0%, psychological 19.7 versus 19.0%, financial mistreatment 8.6 versus 9.5%, sexual 1.0 versus 1.0% and neglect 5.1 versus 3.8% in home and research office, respectively).

CONCLUSION

Our results indicate that the interview setting has no influence both in participation rate and in the prevalence estimates of different types of violence in the elderly.

Healthcare-seeking patterns among immigrants in Portugal

Equity of access to health services is a major concern as it is an important precondition for positive health outcomes. However, inequities in use of health services among immigrant populations persist. Despite the increasing research in the field, patterns of healthcare seeking among immigrant populations and its associated factors are not fully understood. This study aimed to investigate healthcare-seeking patterns among immigrants in Portugal and identify factors associated with utilisation of health services. A cross-sectional study was conducted between October 2008 and May 2009 with a sample of 1,375 immigrants residing in the Lisbon region. Data were collected through a structured questionnaire applied by trained interviewers. Two stepwise logistic regressions were conducted to identify which factors were associated with utilisation of the National Health Service (NHS) and with healthcare seeking for the first time in Portugal at the Primary Health Care service, estimated by calculating odds ratios and 95% confidence intervals. Among participants, around 77% reported having used the NHS; 50% sought health-care for the first time at the Primary Health Care service and 33% at the emergency room. Lower odds of having used the NHS were associated with being male, Brazilian or eastern European compared with being African, and undocumented. Lower odds of having sought health-care for the first time at the Primary Health Care service were associated with being male and undocumented. These results suggest that further efforts are needed to tackle inequalities in access to care and promote the utilisation of health services, particularly among the more vulnerable immigrant groups. Increasing appropriate utilisation of health services, including the primary and preventive care services, may lead to better health outcomes. Immigrants' involvement and participation should be incorporated into the development of health strategies to improve access and utilisation of healthcare services.

[Barriers in access and utilization of health services among immigrants: the perspective of health professionals]

The growing international migration has reinforcing the importance of a greater adequacy of health services in order to respond effectively to immigrants' needs. Previous studies indicate that several difficulties in the access and utilization of health services persist for some immigrant groups. The objective of this study was to understand the perspective of different health professionals' groups about the barriers in access and utilization of services by immigrants. In a transversal study a questionnaire was applied to 320 primary health care professionals of Lisbon and Tagus Valley. Differences between professional groups were analysed using the Kruskal-Wallis test. To determine which groups diverged more in their perceptions, mean ranks of each group were compared. Of the total participants, 64.2% evaluated their knowledge and competencies to deal with immigrants as reasonable however, 15.2% evaluated it as bad. Around one third of professionals admitted to be unaware of the legislation which regulates migrants' access to services. The largest proportion considered that, at the individual level, the frequent change of residence, the lack of economic resources, the cultural and religious beliefs and traditions, the fear of denunciation when the immigrant is undocumented, the lack of knowledge about legislation and services, and the linguistic differences influence access and utilization of health services. Most considered as barriers at the professionals' and services' level the limited sociocultural skills, the complex bureaucratic procedures, the cost and the lack of interpreters. The divergences in the perception of these factors occurred mainly between office workers and the other professionals. The perceptions of health professionals about the barriers in access and utilization of services by immigrants highlight opportunities for intervention in the context of cultural diversity. Given the different perceptions among the professional groups, which may be reflection of the functions they perform, it is reinforced the importance of developing appropriate training to the different professional profiles. The capacity-building of health professionals to deal with cultural diversity may be an important component of human resources training, contributing to better adequate services to the needs of the immigrant.

Alcohol use among 13-year-old adolescents: associated factors and perceptions

OBJECTIVE

To describe the frequency and determinants of alcohol use in a representative sample of 13 years old adolescents, and to analyse qualitatively how adolescents perceive this issue.

STUDY DESIGN

Cross-sectional study with quantitative and qualitative components.

METHODS

Two thousand and thirty-six adolescents attending schools in a city in Portugal were surveyed using a self-reported, structured questionnaire. The qualitative component of the study included 30 semi-structured interviews that intended to assess the reasons for and consequences of drinking as perceived by adolescents, and also the preventive strategies they suggested.

RESULTS

Overall, 50.0% of girls and 44.9% of boys reported that they had experimented with alcohol, and 4.7% of girls and 6.6% of boys drink alcohol at least once per month. Most adolescents recognised that drinking alcohol is harmful and an addiction which is difficult to treat, but this perception was not associated with their own behaviour. Adolescents only identified minor and temporary consequences of drinking alcohol, usually related to very high and acute consumption. In order to prevent alcohol abuse and its consequences, adolescents proposed measures based on strict control, legal restrictions and economic measures, some of which are already in place in Portugal.

CONCLUSION

A high proportion of adolescents had experimented with alcohol by 13 years of age, showing the importance of starting prevention at an early life stage. The results also reflect the importance of reviewing prevention programmes in schools, highlighting the importance of families.

Physical fighting among school-going Portuguese adolescents: social and behavioural correlates

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.

Burnout and engagement in portuguese nurses working with mental illness

Introduction

In 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).

Aims

Identify the levels of burnout and engagement of nurses working with mental illness.

Methods

Data 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.

Results

Our 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.

Conclusions

Despite 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.

Avaliação dos cuidados de saúde: percepções de mulheres imigrantes em Portugal

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.

Independent factors associated with depression in type 1 diabetes mellitus

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.

Checking consistency in mixed treatment comparison meta-analysis

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.

Chemo-angiogenic profile of bovine urinary bladder tumors distinguishes urothelial carcinomas from hemangiosarcomas

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.

Coccoid form of Helicobacter pylori as a morphological manifestation of cell adaptation to the environment

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.

Long-term pituitary down-regulation before in vitro fertilization (IVF) for women with endometriosis

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.

Electron spin resonance and raman scattering spectroscopy of multi-walled carbon nanotubes: a function of acid treatment

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.

Optimized culture conditions for the generation of dendritic cells from peripheral blood monocytes

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.

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

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.

Anagrelide metabolite induces thrombocytopenia in mice by inhibiting megakaryocyte maturation without inducing platelet aggregation

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.

Impaired recruitment of bone-marrow-derived endothelial and hematopoietic precursor cells blocks tumor angiogenesis and growth

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.