The role of confinement and corona crystallinity on the bending modulus of copolymer micelles measured directly by AFM flexural tests.

We present an approach which makes it possible to directly determine the bending modulus of single elongated block copolymer micelles. This is done by forming arrays of suspended micelles onto microfabricated substrates and by performing three-point bending flexural tests, using an atomic force microscope, on their suspended portions. By coupling the direct atomic force microscopy measurements with differential scanning calorimetry data, we show that the presence of a crystalline corona strongly increases the modulus of the copolymer elongated micelles. This large increase suggests that crystallites in the corona are larger and more uniformly oriented due to confinement effects. Our findings together with this hypothesis open new interesting avenues for the preparation of core-templated polymer fibres with enhanced mechanical properties.

Blocking interferon {beta} stimulates vascular smooth muscle cell proliferation and arteriogenesis.

Increased interferon (IFN)-ß signaling in patients with insufficient coronary collateralization and an inhibitory effect of IFNß on collateral artery growth in mice have been reported. The mechanisms of IFNß-induced inhibition of arteriogenesis are unknown. In stimulated monocytes from patients with chronic total coronary artery occlusion and decreased arteriogenic response, whole genome expression analysis showed increased expression of IFNß-regulated genes. Immunohistochemically, the IFNß receptor was localized in the vascular media of murine collateral arteries. Treatment of vascular smooth muscle cells (VSMC) with IFNß resulted in an attenuated proliferation, cell-cycle arrest, and increased expression of cyclin-dependent kinase inhibitor-1A (p21). The growth inhibitory effect of IFNß was attenuated by inhibition of p21 by RNA interference. IFNß-treated THP1 monocytes showed enhanced apoptosis. Subsequently, we tested if collateral artery growth can be stimulated by inhibition of IFNß-signaling. RNA interference of the IFNß receptor-1 (IFNAR1) increased VSMC proliferation, cell cycle progression, and reduced p21 gene expression. IFNß signaling and FAS and TRAIL expression were attenuated in monocytes from IFNAR1(-/-) mice, indicating reduced monocyte apoptosis. Hindlimb perfusion restoration 1 week after femoral artery ligation was improved in IFNAR1(-/-) mice compared with wild-type mice as assessed by infusion of fluorescent microspheres. These results demonstrate that IFNß inhibits collateral artery growth and VSMC proliferation through p21-dependent cell cycle arrest and induction of monocyte apoptosis. Inhibition of IFNß stimulates VSMC proliferation and collateral artery growth.

Experts' opinions on ethical issues of genetic research into Alzheimer's disease: results of a Delphi study in the Netherlands.

Most publications on the ethical aspects of genetic research into Alzheimer's Disease (AD) concentrate on the differences between the opinions of professionals and non-professionals. Differences in rating of morally relevant issues between groups of professionals have not yet been described. A modified Delphi study in two rounds was held to identify differences between groups of experts (i.e. clinicians, representatives of patient organisations, ethicists and persons with a commercial background). The strongest correlation was found between the opinions of ethicists and representatives of patient organisations (0.67) and between clinicians and ethicists (0.62). Moderate correlation (0.55) was found between the opinions of clinicians and representatives of patient organisations. Persons with a commercial background showed a weak correlation with clinicians (0.41), ethicists (0.35) and representatives of patient organisations (0.30). These differences in rating of morally relevant issues between various professional groups are relevant for clinical practice and dementia care, particularly the different rating of prenatal diagnosis found between clinicians and representatives of patient organisations. Interdisciplinary consultations between various professional groups -including at least researchers, clinicians and ethicists -are recommended to guarantee that all considerations will be incorporated into the debate on ethical issues of genetic research into AD.

Sex differences in self-regulation in early, middle and late adolescence: A large-scale cross-sectional study.

This large-scale cross-sectional study had the aim to investigate whether adolescent males and females differ in self-perceived self-regulation. The large sample size allowed us to investigate sex differences in three age-groups of young (n = 161), middle (n = 133) and late (n = 159) adolescents. Self-regulation was evaluated with a self-report questionnaire, the Amsterdam Executive Functioning Inventory (AEFI). This questionnaire gives a proxi for three executive functions that are important for proper self-regulation: (1) self-control & self-monitoring, (2) attention, and (3) planning & initiative taking. Results revealed clear sex differences in the self-regulation as perceived by mid-adolescents (i.e., 13-16 years). In this age period, females evaluated their attention higher than males, and they reported higher levels of self-control & self-monitoring. Our findings offer important new insights with respect to the decision making, academic achievements and behaviour of 13-16-year olds. Self-regulation is known to have a central role in academic achievement and in behavioural organisation. The sex differences in self-regulation in mid-adolescence may therefore explain part of the difference which males and females in this age-group exhibit in academic achievements and behavioural organisations. The results imply that self-regulation may be a relevant intervention target: rather than focussing on changing behaviour, interventions may focus more on self-insights and thereby changing the adolescent's perceptions about their behaviour. Increased self-insight may have the potency to actually change behaviour, which might be an interesting target for future investigation.

Gemcitabine uptake in glioblastoma multiforme: potential as a radiosensitizer.

Glioblastoma multiforme (GBM), the most frequent malignant brain tumor, has a poor prognosis, but is relatively sensitive to radiation. Both gemcitabine and its metabolite difluorodeoxyuridine (dFdU) are potent radiosensitizers. The aim of this phase 0 study was to investigate whether gemcitabine passes the blood-tumor barrier, and is phosphorylated in the tumor by deoxycytidine kinase (dCK) to gemcitabine nucleotides in order to enable radiosensitization, and whether it is deaminated by deoxycytidine deaminase (dCDA) to dFdU. Gemcitabine was administered at 500 or 1000 mg/m(2) just before surgery to 10 GBM patients, who were biopsied after 1-4 h. Plasma gemcitabine and dFdU levels varied between 0.9 and 9.2 microM and 24.9 and 72.6 microM, respectively. Tumor gemcitabine and dFdU levels varied from 60 to 3580 pmol/g tissue and from 29 to 72 nmol/g tissue, respectively. The gene expression of dCK (beta-actin ratio) varied between 0.44 and 2.56. The dCK and dCDA activities varied from 1.06 to 2.32 nmol/h/mg protein and from 1.51 to 5.50 nmol/h/mg protein, respectively. These enzyme levels were sufficient to enable gemcitabine phosphorylation, leading to 130-3083 pmol gemcitabine nucleotides/g tissue. These data demonstrate for the first time that gemcitabine passes the blood-tumor barrier in GBM patients. In tumor samples, both gemcitabine and dFdU concentrations are high enough to enable radiosensitization, which warrants clinical studies using gemcitabine in combination with radiation.

Bone marrow cell therapy after acute myocardial infarction: the HEBE trial in perspective, first results.

During the last decennium, the role of bone marrow mononuclear cells (BMMC) has been underscored in the healing process after acute myocardial infarction (AMI). Although these cells improve left ventricular recovery after AMI in experimental studies, results from large-scale randomised trials investigating BMMC therapy in patients with AMI have shown contradictory results. To address this issue the HEBE study was designed, a multicentre, randomised trial, evaluating the effects of intracoronary infusion of BMMCs and the effects of intracoronary infusion of peripheral blood mononuclear cells after primary percutaneous coronary intervention. The primary endpoint of the HEBE trial is the change in regional myocardial function in dysfunctional segments at four months relative to baseline, based on segmental analysis as measured by magnetic resonance imaging. The results from the HEBE trial will provide detailed information about the effects of intracoronary BMMC therapy on post-infarct left ventricular recovery. In addition, further analysis of the data and material obtained may provide important mechanistic insights into the contribution of BMMCs to natural recovery from AMI as well as the response to cell therapy. This may significantly contribute to the development of improved cell-based therapies, aiming at optimising post-infarct recovery and preventing heart failure. (Neth Heart J 2008;16:436-9.).

Quality of life, delinquency and psychosocial functioning of adolescents in secure residential care: testing two assumptions of the Good Lives Model.

BACKGROUND: In this study, two assumptions derived from the Good Lives Model were examined: whether subjective Quality of Life is related to delinquent behaviour and psychosocial problems, and whether adolescents with adequate coping skills are less likely to commit delinquent behaviour or show psychosocial problems. METHOD: To this end, data of 95 adolescents with severe psychiatric problems who participated in a four-wave longitudinal study were examined. Subjective Quality of Life was assessed with the ten domains of the Lancashire Quality of Life Profile and coping skills with the Utrecht Coping List for Adolescents. RESULTS: Results showed that adolescents who reported a lower Quality of Life on the health domain had more psychosocial problems at follow-up. No relationship was found between Quality of Life and delinquent behaviour. In addition, active and passive coping were associated with delinquent behaviour and psychosocial functioning at follow-up. CONCLUSIONS: Based on the results of this longitudinal study, the strongest support was found for the second assumption derived from the Good Lives Model. Adolescents with adequate coping skills are less likely to commit delinquent behaviour and have fewer psychosocial problems at follow-up. The current study provides support for the use of strength-based elements in the treatment programmes for adolescents in secure residential care.

The synergistic interaction of gemcitabine and cytosine arabinoside with the ribonucleotide reductase inhibitor triapine is schedule dependent.

Gemcitabine and ara-C have multiple mechanisms of action: DNA incorporation and for gemcitabine also ribonucleotide reductase (RNR) inhibition. Since dCTP competes with their incorporation into DNA, dCTP depletion can potentiate their cytotoxicity. We investigated whether additional RNR inhibition by Triapine (3-AP), a new potent RNR inhibitor, enhanced cytotoxicity of gemcitabine and ara-C in four non-small-cell-lung-cancer (NSCLC) cell lines, using the multiple-drug-effect analysis. Simultaneous and sequential exposure (preexposure to 3-AP for 24h) in a constant molar ratio of 3-AP and gemcitabine was antagonistic/additive in all cell lines. Preexposure to 3-AP at an IC(25) concentration for 24h before variable concentrations of gemcitabine was synergistic. RNR inhibition by 3-AP resulted in a more synergistic interaction in combination with ara-C, which does not inhibit RNR. Two cell lines with pronounced synergism (SW1573) or antagonism (H460) for gemcitabine/3-AP, were evaluated for accumulation of the active metabolites, dFdCTP and ara-CTP. Simultaneous exposure induced no or a small increase, but ara-CTP increased after pretreatment with 3-AP, 4-fold in SW1573 cells, but not in H460 (<1.5 fold). Ara-C and gemcitabine incorporation into DNA were more pronounced (about 2-fold increased) for sequential treatment in SW1573 compared to H460 cells (<1.5 fold). This was not related to the activity and expression of deoxycytidine kinase and the M2 subunit of RNR. In conclusion, RNR inhibition by 3-AP prior to gemcitabine or ara-C exposure stimulates accumulation of the active metabolites and incorporation into DNA. The combination 3-AP/Ara-C is more synergistic than 3-AP/gemcitabine possibly because gemcitabine already inhibits RNR, but ara-C does not.

The determination of gemcitabine and 2'-deoxycytidine in human plasma and tissue by APCI tandem mass spectrometry.

A fast, sensitive and accurate method for the determination of gemcitabine (difluorodeoxycytidine; dFdC) and deoxycytidine (CdR) in human plasma/tissue was developed using LC-MS/MS techniques. Effectiveness of the method is illustrated with the analysis of plasma from a phase I trial of dFdC administered as a 24h infusion. The method was developed using (15)N(3) CdR as an internal standard across the concentration range of 1-500ng/ml, using a cold alcohol-protein precipitation followed by desorption with freeze drying. Sample clean-up for LC-MS/MS analysis was performed by an innovative liquid/liquid back extraction with ethyl acetate and water. Chromatography was performed using a Chrompak-spherisorb-phenyl-column (3.1mmx200mm, 5microm) with a 50mM formic acid: acetonitrile (9:1) mobile phase eluted at 1ml/min. Extracted samples were observed to be stable for a minimum of 48h after extraction when kept at 4 degrees C. Detection was performed using an atmospheric pressure chemical ionization (APCI) source and mass spectrometric positive multi-reaction-monitoring-mode (+MRM) for dFdC (264 m/z; 112 m/z), CdR (228 m/z; 112 m/z), and (15)N(3) CdR (231 m/z; 115 m/z) at an ion voltage of +3500V. The accuracy, precision and limit-of-quantitation (LOQ) were as follows: dFdC: 99.8%, +/-7.9%, 19nM; CdR: 100.0%, +/-5.3%, 22nM, linear range LOQ to 2microM. During 24h infusion dFdC levels were detected with no interference from either CdR or difluorodeoxyuridine (dFdU). CdR co-eluted with dFdC but selectivity demonstrated no "crosstalk" between the compounds. In conclusion the analytical assay was very sensitive, reliable and robust for the determination of plasma and tissue concentrations of dFdC and CdR.

Clinical phase I and pharmacology study of gemcitabine (2', 2'-difluorodeoxycytidine) administered in a two-weekly schedule.

Gemcitabine (dFdC) was tested in a Phase I trial at 14 doses (40-5700 mg/m(2)), administered every 2 weeks as a (1/2) -h infusion to 52 patients with refractory solid cancer. Gemcitabine and its deaminated metabolite difluorodeoxyuridine (dFdU), measured with HPLC, reached plasma peak levels of 2-3 microM at 40 mg/m(2) which increased to 512 microM at 5700 mg/m(2). Gemcitabine was eliminated rapidly with a t(1/2) beta of 2.3-15.8 min in the 40-5700 mg/m(2) dose range, with one exception of 38 min at 4500 mg/m(2) . dFdU was still present at a plateau of +/- 20 microM from 4-24 h at doses >960 mg/m(2). Up to 3650 mg/m(2) linear pharmacokinetics were observed for gemcitabine, while those for dFdU were linear over the whole range. Gemcitabine clearance varied between 1.5-12.6 l/min and was 1.5-fold higher in males than in females (p= 0.024); its volume of distribution was 45.2-248 l. In lymphocytes peak levels of the active metabolite dFdCTP were 100-380 pmol/10( 6 )cells in the first course. Apparently a plateau was reached which was confirmed by incubation of white blood cells with increasing gemcitabine concentrations up to 500 microM, reaching a plateau of about 350 pmol/10(6 )cells; in contrast in cancer cells this concentration dependence did not exist and accumulation reached about 1590 pmol/10( 6 )cells. In tumors isolated from patients treated with gemcitabine dFdCTP reached about 70 pmol/g wet weight. Gemcitabine itself was eliminated only to a limited extent in the urine, but dFdU was eliminated almost completely in the urine in the first 24 h (51-92%). In conclusion, dFdC was rapidly eliminated in contrast to dFdU, which was present for at least 18 h, as well as dFdCTP in lymphocytes.

The role of thymidine phosphorylase and uridine phosphorylase in (fluoro)pyrimidine metabolism in peripheral blood mononuclear cells.

Thymidine phosphorylase (TP) and uridine phosphorylase (UP) catalyze the (in)activation of several fluoropyrimidines, depending on their catalytic activity and substrate specificity. Blood cells are the first compartment exposed to most anticancer agents. The role of white blood cells in causing toxic side effects and catalyzing drug metabolism is generally underestimated. Therefore we determined the contribution of the white blood cell compartment to drug metabolism, and we investigated the activity and substrate specificity of TP and UP for the (fluoro)pyrimidines thymidine (dThd), uridine (Urd), 5'-deoxy-5-fluorouridine (5' dFUrd) and 5-fluorouracil (5FU) in peripheral blood mononuclear cells (PBMC) and undifferentiated monocytes and differentiated monocytes: macrophages and dendritic cells. PBMC had an IC50 of 742 microM exposed to 5'dFUrd, increasing to > 2000 microM when both TP and UP activities were inhibited. Total phosphorolytic activity was higher with dThd than with Urd, 5'dFUrd or 5FU. Using a specific TP inhibitor (TPI) and UP inhibitor (BAU) we concluded that dThd and Urd were preferentially converted by TP and UP, respectively, while 5'dFUrd and 5FU were mainly converted by TP (about 80%) into 5FU and FUrd, respectively. 5FU was effectively incorporated into RNA. dThd conversion into thymine was highest in dendritic cells (52.6 nmol thymine/h/10(6) cells), followed by macrophages (two-fold) and undifferentiated monocytes (eight-fold). TPI prevented dThd conversion almost completely. In conclusion, PBMC were relatively insensitive to 5'dFUrd, and the natural substrates dThd and Urd were preferentially converted by TP and UP, respectively. TP and UP were both responsible for converting 5'dFUrd/5FU into 5FU/FUrd, respectively.

Analysis of deoxycytidine accumulation in gemcitabine treated patients.

Deoxycytidine (CdR) analogs are increasingly popular as chemotherapeutic agents and their effectiveness can be linked to the direct competition with active forms of endogenous CdR. A tandem mass spectrometric assay was developed to determine the plasma concentrations of CdR. Plasma extracts were prepared by protein precipitation and an ethyl acetate/water back extraction, and then separated chromatographically. Detection parameters were optimized for multi-reaction monitoring (MRM) tandem mass spectrometry and assay efficiency was improved using 15N3 CdR as an isotopic internal standard. Preliminary results from a gemcitabine trial are shown which indicate that CdR concentrations increase systemically during infusion, from about 5 nM to 78 nM after hepatic artery infusion and to 102 nM after systemic infusion for 24 hours. The developed assay demonstrated good sensitivity and selectivity for CdR.

In vivo biodistribution of stable spherical and filamentous micelles probed by high-sensitivity SPECT.

Understanding how nanoparticle properties such as size, morphology and rigidity influence their circulation time and biodistribution is essential for the development of nanomedicine therapies. Herein we assess the influence of morphology on cellular internalization, in vivo biodistribution and circulation time of nanocarriers using polystyrene-b-poly(ethylene oxide) micelles of spherical or elongated morphology. The glassy nature of polystyrene guarantees the morphological stability of the carriers in vivo and by encapsulating Indium-111 in their core, an assessment of the longitudinal in vivo biodistribution of the particles in healthy mice is performed with single photon emission computed tomography imaging. Our results show prolonged blood circulation, longer than 24 hours, for all micelle morphologies studied. Dynamics of micelle accumulation in the liver and other organs of the reticuloendothelial system show a size-dependent nature and late stage liver clearance is observed for the elongated morphology. Apparent contradictions between recent similar studies can be resolved by considering the effects of flexibility and degradation of the elongated micelles on their circulation time and biodistribution.

Bivariate linear models in neurobiology: problems of concept and methodology.

Bivariate linear models, used to describe morphological and functional characteristics between two sets of observations, are examined both in concept and in application. This paper focuses on the underlying assumptions and statistics of the method most frequently used: ordinary linear regression, principal axis and standard major axis. It is shown how the choice of method should depend on: the purpose of the analysis and the a priori assumptions regarding the residual variance. It appears that none of the methods has a universal application. Differences among the models discussed are illustrated by a bivariate morphometric analysis of cerebrocortical regions in primates.

Delinquency, health behaviour and health.

OBJECTIVES: This study investigated the association between delinquency and health in a sample of adolescents and young adults (aged 13-24) and examined whether the association could have been due to delinquency-related differences in demographic, socio-economic and life-style factors. METHOD: The study is based on cross-sectional data from a sample of 3677 adolescents and young adults interviewed as part of a survey of Dutch households. Health, health behaviour, and delinquency were assessed through self-report measures. RESULTS: Delinquency was significantly related to three of the four measures of health behaviour (smoking, alcohol consumption, and drug use), even after control for demographic and socio-economic factors. Delinquency was also significantly associated with all three measures of health assessed in this study (somatic symptoms, general health, and chronic conditions). However, only minimal support was found for the hypothesis that the association between delinquency and health was mediated by differences in health behaviour or demographic/socio-economic differences. CONCLUSIONS: Adolescent delinquents are less healthy than non-delinquents. Potential causes for this relationship are proposed. Possibly, personality factors, such as hostility, or psychosocial stress might explain why delinquency correlates with health.

Contribution to the aetiology of synovitis in chickens, with special reference to non-infective factors. V. Extractability of glucosaminoglycans/mucoproteins from tendon tissue.

A comparative study was undertaken regarding the extractability of glucosaminoglycans and mucoproteins in the tendon tissue of birds highly susceptible to synovitis, viz.broiler breed cocks (BB cocks), and of birds highly resistant to synovitis. viz. White Leghorn hens (WL hens). It was shown that in ;the case of WL hens this extractability decreased in accordance with ageing. In the case of BB cocks such a decrease was not observed. This observation is in support of a working hypothesis which supposes a relatively high degree of interaction between the several components of tendon components of tendon tissue (e.g. collagen and glucosaminoglycans/mucoproteins) in the case of WL hens, and a relatively low degree of this interaction in the case of BB cocks. Moreover the results of this study account for the observation that the tendon tissue of WL hens is more resistant to tensile stress than that of BB cocks, and they indicate that the above interaction is a determinant in the aetiology of synovitis.

Efficacy of toltrazuril in broilers and development of a laboratory model for sensitivity testing of Eimeria field isolates.

(1) The efficacy of toltrazuril (Baycox) against coccidiosis was established on a broiler farm in an intermittent application during five consecutive growing periods. Treated birds were fed a broiler ration without anticoccidials. The efficacy of Baycox was compared with the nicarbazin-salinomycin shuttle. It was concluded that Baycox retarded the onset of Eimeria infection for several weeks. During the fifth rearing period coccidiosis problems emerged on the farm in all birds during medication, suggesting development of resistance. (2) During a laboratory experiment the efficacy of Baycox was studied in birds after inoculation with different numbers of oocysts at 7, 10 or 15 days of age. Baycox was applied at 10 and 11 days of age. In all cases medication with Baycox protected birds from coccidiosis during a period of at least 7 days. This effect of Baycox could be due to the long-existing tissue levels of the product and its metabolites as well as its specific effect on the second generation of schizonts. (3) In another laboratory experiment coccidia obtained from field trials were tested for sensitivity to Baycox in conjunction with two strains obtained from farms were coccidiosis emerged during application. The inoculation model developed in this study was used for sensitivity testing. One of the Eimeria strains tested was resistant to the product, one strain was tolerant and the remaining two strains, including the control strain, were fully sensitive to Baycox.

Induction of a monocyte/macrophage phenotype switch by mesenchymal stem cells might contribute to improved infarct healing postacute myocardial infarction.

Inadequate healing following acute myocardial infarction (AMI) can lead to the development of heart failure. The ischemic myocardium triggers an inflammatory response that clears cell debris and initiates the onset of scar tissue formation. The duration and intensity of this inflammatory response have been linked to the cardiac functioning post-AMI. In order to diminish scar tissue formation and stimulate regeneration of cardiac tissue, mesenchymal stem cell (MSC) have been applied post-AMI and showed beneficial effects on cardiac function. However, other than the expected regeneration of cardiac tissue, modulation of the inflammatory response post-AMI, especially related to an effect on monocytes/macrophages, was recently found to be an important aspect of MSC therapy. In healing post-AMI, monocytes and macrophages are key players that can either stimulate or repress inflammation using different phenotypes. Increased levels of the proinflammatory phenotype have clinically been associated with poor cardiac functional outcome post-AMI. MSC have been suggested to switch the monocytes/macrophages phenotype into a more anti-inflammatory state and might therefore beneficially influence the duration and intensity of the inflammatory response and subsequent cardiac function post-AMI. To gain more insight into this effect of MSC, this review provides an overview of the most relevant studies regarding this modulatory effect of MSC on monocytes/macrophages including its mechanisms to improve cardiac functioning post-AMI.

Clinical parameters associated with collateral development in patients with chronic total coronary occlusion.

OBJECTIVE: Well-developed collaterals provide survival benefit in patients with obstructive coronary artery disease (CAD). Therefore, in this study we sought to determine which clinical variables are associated with arteriogenesis. DESIGN: Clinical and laboratory variables were collected before percutaneous coronary intervention. Multivariate analysis was performed to determine which variables are associated with the collateral flow index (CFI). PATIENTS: Data from 295 chronic total occlusion (CTO) patients (Bern, Switzerland, Amsterdam, the Netherlands and Jena, Germany) were pooled. In earlier studies, patients had varying degrees of stenosis. Therefore, different stages of development of the collaterals were used. In our study, a unique group of patients with CTO was analysed. INTERVENTIONS: Instead of angiography used earlier, we used a more accurate method to determine CFI using intracoronary pressure measurements. CFI was calculated from the occlusive pressure distal of the coronary lesion, the aortic pressure and central venous pressure. RESULTS: The mean CFI was 0.39 ± 0.14. After multivariate analysis, ß blockers, hypertension and angina pectoris duration were positively associated with CFI (B: correlation coefficient ß=0.07, SE=0.03, p=0.02, B=0.040, SE=0.02, p=0.042 and B=0.001, SE=0.000, p=0.02). Furthermore also after multivariate analysis, high serum leucocytes, prior myocardial infarction and high diastolic blood pressure were negatively associated with CFI (B=-0.01, SE=0.005, p=0.03, B=-0.04, SE=0.02, p=0.03 and B=-0.002, SE=0.001, p=0.011). CONCLUSIONS: In this unique cohort, high serum leucocytes and high diastolic blood pressure are associated with poorly developed collaterals. Interestingly, the use of ß blockers is associated with well-developed collaterals, shedding new light on the potential action mode of this drug in patients with CAD.

Surfing the data tsunami, a bioinformatic dissection of the proangiogenic monocyte.

In this review we compare expression studies on monocyte subsets as an example to show the integrated possibilities of molecular databases and bioinformatic analysis tools. Monocytes have been recognized as cells with great plasticity and differentiation potential that play a pivotal role in revascularization processes, i.e. angiogenesis and arteriogenesis. To gain more insight in the relevant developmental programs, we compared the full-genome mRNA expression profiles of several distinct human monocyte subpopulations previously identified based on surface marker expression. These included classical and non-classical, M1 and M2 macrophages, circulating angiogenic cells (CAC), and non-monocyte-derived endothelial colony-forming cells (ECFC). Their transcriptional profiles revealed distinct and overlapping gene expression signatures and pathways reminiscent of utilization of transcription factors driving polarization into the different monocytic phenotypes. Hierarchical cluster analysis revealed that CAC are most related to M2 macrophages and unstimulated macrophages, and to a lesser extent to classical monocytes, and are quite distinct from M1 macrophages and ECFC. Analysis of the promoter region of CAC-expressed genes suggests that in particular the ETS family of transcription factors is important in CAC development. These analyses show the power of combining multiple datasets with existing databases on biological knowledge, to interpret full genome expression data.