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1.  BCL-2 inhibition targets oxidative phosphorylation and selectively eradicates quiescent human leukemia stem cells 
Cell stem cell  2013;12(3):329-341.
Most forms of chemotherapy employ mechanisms involving induction of oxidative stress, a strategy that can be effective due to the elevated oxidative state commonly observed in cancer cells. However, recent studies have shown that relative redox levels in primary tumors can be heterogeneous, suggesting that regimens dependent on differential oxidative state may not be uniformly effective. To investigate this issue in hematological malignancies, we evaluated mechanisms controlling oxidative state in primary specimens derived from acute myelogenous leukemia (AML) patients. Our studies demonstrate three striking findings. First, the majority of functionally-defined leukemia stem cells (LSCs) are characterized by relatively low levels of reactive oxygen species (termed “ROS-low”). Second, ROS-low LSCs aberrantly over-express BCL-2. Third, BCL-2 inhibition reduced oxidative phosphorylation and selectively eradicated quiescent LSCs. Based on these findings, we propose a model wherein the unique physiology of ROS-low LSCs provides an opportunity for selective targeting via disruption of BCL-2-dependent oxidative phosphorylation.
PMCID: PMC3595363  PMID: 23333149
Acute myeloid leukemia; AML; leukemia; leukemia stem cells; LSCs; oxidative phosphorylation; glycolysis; BCL-2; ABT-263; reactive oxygen species; ROS; oxidative state; energy metabolism
2.  Prostaglandin E2 increases hematopoietic stem cell survival and accelerates hematopoietic recovery after radiation injury 
Stem cells (Dayton, Ohio)  2013;31(2):372-383.
Hematopoietic stem and progenitor cells (HSPCs), which continuously maintain all mature blood cells, are regulated within the marrow microenvironment. We previously reported that pharmacologic treatment of naïve mice with prostaglandin E2 (PGE2) expands HSPCs. However, the cellular mechanisms mediating this expansion remain unknown. Here we demonstrate that PGE2 treatment in naïve mice inhibits apoptosis of HSPCs without changing their proliferation rate. In a murine model of sub-lethal total body irradiation (TBI), in which HSPCs are rapidly lost, treatment with a long-acting PGE2 analogue (dmPGE2) reversed the apoptotic program initiated by TBI. dmPGE2 treatment in vivo decreased the loss of functional HSPCs following radiation injury, as demonstrated both phenotypically and by their increased reconstitution capacity. The antiapoptotic effect of dmPGE2 on HSPCs did not impair their ability to differentiate in vivo, resulting instead in improved hematopoietic recovery after TBI. dmPGE2 also increased microenvironmental cyclooxygenase-2 expression and expanded the α-SMA+ subset of marrow macrophages, thus enhancing the bone marrow microenvironmental response to TBI. Therefore, in vivo treatment with PGE2 analogues may be particularly beneficial to HSPCs in the setting of injury by targeting them both directly and also through their niche. The current data provide rationale for in vivo manipulation of the HSPC pool as a strategy to improve recovery after myelosuppression.
PMCID: PMC3580384  PMID: 23169593
3.  Tophus measurement as an outcome measure for clinical trials of chronic gout: progress and research priorities 
The Journal of rheumatology  2011;38(7):10.3899/jrheum.110272.
Despite the recognition that tophus regression is an important outcome measure in clinical trials of chronic gout, there is no agreed method of tophus measurement. A number of methods have been used in clinical trials of chronic gout, from simple physical measurement techniques to complex advanced imaging methods. This paper summarises the methods of tophus measurement that have been used and discusses the properties of these methods. Physical measurement using Vernier calipers fulfils most aspects of the Outcomes Measures in Rheumatology (OMERACT) filter. Rigorous testing of the complex methods, particularly with respect to reliability and sensitivity to change is needed, to determine the appropriate use of these methods. Further information is also required regarding which method of physical measurement is best for use in future clinical trials. The need to develop and test a patient reported measure of tophus burden is also highlighted.
PMCID: PMC3882031  PMID: 21724716
4.  LORD-Q: a long-run real-time PCR-based DNA-damage quantification method for nuclear and mitochondrial genome analysis 
Nucleic Acids Research  2013;42(6):e41.
DNA damage is tightly associated with various biological and pathological processes, such as aging and tumorigenesis. Although detection of DNA damage is attracting increasing attention, only a limited number of methods are available to quantify DNA lesions, and these techniques are tedious or only detect global DNA damage. In this study, we present a high-sensitivity long-run real-time PCR technique for DNA-damage quantification (LORD-Q) in both the mitochondrial and nuclear genome. While most conventional methods are of low-sensitivity or restricted to abundant mitochondrial DNA samples, we established a protocol that enables the accurate sequence-specific quantification of DNA damage in >3-kb probes for any mitochondrial or nuclear DNA sequence. In order to validate the sensitivity of this method, we compared LORD-Q with a previously published qPCR-based method and the standard single-cell gel electrophoresis assay, demonstrating a superior performance of LORD-Q. Exemplarily, we monitored induction of DNA damage and repair processes in human induced pluripotent stem cells and isogenic fibroblasts. Our results suggest that LORD-Q provides a sequence-specific and precise method to quantify DNA damage, thereby allowing the high-throughput assessment of DNA repair, genotoxicity screening and various other processes for a wide range of life science applications.
PMCID: PMC3973301  PMID: 24371283
5.  Patient-reported Outcomes in Chronic Gout: A Report from OMERACT 10 
The Journal of rheumatology  2011;38(7):10.3899/jrheum.110271.
To summarize the endorsement of measures of patient-reported outcome (PRO) domains in chronic gout at the 2010 Outcome Measures in Rheumatology Meeting (OMERACT 10).
During the OMERACT 10 gout workshop, validation data were presented for key PRO domains including pain [pain by visual analog scale (VAS)], patient global (patient global VAS), activity limitation [Health Assessment Questionnaire-Disability Index (HAQ-DI)], and a disease-specific measure, the Gout Assessment Questionnaire version 2.0 (GAQ v2.0). Data were presented on all 3 aspects of the OMERACT filters of truth, discrimination, and feasibility. One PRO, health-related quality of life measurement with the Medical Outcomes Study Short-form 36 (SF-36), was previously endorsed at OMERACT 9.
One measure for each of the 3 PRO of pain, patient global, and activity limitation was endorsed by > 70% of the OMERACT delegates to have appropriate validation data. Specifically, pain measurement by VAS was endorsed by 85%, patient global assessment by VAS by 73%, and activity limitation by HAQ-DI by 71%. GAQ v2.0 received 30% vote and was not endorsed due to several concerns including low internal consistency and lack of familiarity with the measure. More validation studies are needed for this measure.
With the endorsement of one measure each for pain, patient global, SF-36, and activity limitation, all 4 PRO for chronic gout have been endorsed. Future validation studies are needed for the disease-specific measure, GAQ v2.0. Validation for PRO for acute gout will be the focus of the next validation exercise for the OMERACT gout group.
PMCID: PMC3850171  PMID: 21724715
6.  A Revised Estimate of the Burden of Illness of Gout☆ 
Gout is a chronic, inflammatory arthritis characterized by painful and debilitating acute/episodic flares. Until recently, gout has been regarded as a minor medical problem, in part because the associated economic burden has not been appreciated. Previous literature on this subject focused on the costs associated with acute episodes of gout rather than on the long-term medical and economic implications of this chronic disorder.
Our aim was to estimate the current impact of gout in the United States with respect to disability and economic costs.
The following data sources were used: published data on the incremental economic burden of gout; statistics from the US Census Bureau and the US Bureau of Labor Statistics; and recent epidemiological and clinical literature concerning the course, treatment, and outcomes of the disease. Disability is expressed as days of lost productivity. Charges for gout-related treatments were used as direct cost inputs.
Gout affects an estimated 8 million Americans, among whom those working have an average of almost 5 more absence days annually than workers without gout. On average, the incremental annual cost of care for a gout patient is estimated at >$3000 compared with a nongouty individual. Even though comorbidities common in gout patients account for a portion of this increased economic burden, the total annual cost attributable to gout patients in the United States is likely in the tens of billions of dollars and comparable to those of other major chronic disorders, such as migraine and Parkinson’s disease.
The economic burden of gout is most readily assessable in patients whose acute arthritic flares result in emergency department visits, bedridden days, and episodic loss of productivity. Chronic progression of the disease can also result in long-term impairment of function and health-related quality of life, but the contribution of chronic gout to the economic burden is more difficult to quantitate because gout is frequently associated with serious cardiovascular, metabolic, and renal comorbidities. Recent demonstration that successful gout management can reverse functional deficits in many chronic gout patients, however, supports the views that chronic gout contributes substantially to the medical and thus economic costs of these patients and that early and aggressive efforts to improve gout outcomes are likely to reduce the associated economic burden.
PMCID: PMC3898191  PMID: 24465034
burden of illness; gout
7.  Tophus burden reduction with pegloticase: results from phase 3 randomized trials and open-label extension in patients with chronic gout refractory to conventional therapy 
Arthritis Research & Therapy  2013;15(5):R137.
Two replicate randomized, placebo-controlled six-month trials (RCTs) and an open-label treatment extension (OLE) comprised the pegloticase development program in patients with gout refractory to conventional therapy. In the RCTs, approximately 40% of patients treated with the approved dose saw complete response (CR) of at least one tophus. Here we describe the temporal course of tophus resolution, total tophus burden in patients with multiple tophi, tophus size at baseline, and the relationship between tophus response and urate-lowering efficacy.
Baseline subcutaneous tophi were analyzed quantitatively using computer-assisted digital images in patients receiving pegloticase (8 mg biweekly or monthly) or placebo in the RCTs, and pegloticase in the OLE. Tophus response, a secondary endpoint in the trials, was evaluated two ways. Overall tophus CR was the proportion of patients achieving a best response of CR (without any new/enlarging tophi) and target tophus complete response (TT-CR) was the proportion of all tophi with CR.
Among 212 patients randomized in the RCTs, 155 (73%) had ≥1 tophus and 547 visible tophi were recorded at baseline. Overall tophus CR was recorded in 45% of patients in the biweekly group (P = 0.002 versus placebo), 26% in the monthly group, and 8% in the placebo group after six months of RCT therapy. TT-CR rates at six months were 28%, 19%, and 2% of tophi, respectively. Patients meeting the primary endpoint of sustained urate-lowering response to therapy (responders) were more likely than nonresponders to have an overall tophus CR at six months (54% vs 20%, respectively and 8% with placebo).
Both overall tophus CR and TT-CRs increased with treatment duration in the OLE, reaching 70% (39/56) of patients and 55% (132/238) of target tophi after one year of treatment in patients receiving pegloticase during both the RCTs and OLE. At that time point, more tophi had resolved in responders (102/145 or 70% of tophi) than nonresponders (30/93; 32%).
Pegloticase reduced tophus burden in patients with refractory tophaceous gout, especially those achieving sustained urate-lowering. Complete resolution of tophi occurred in some patients by 13 weeks and in others with longer-term therapy.
Trial registrations
NCT00325195, NCT01356498
PMCID: PMC3979037  PMID: 24286509
8.  High-dose therapy and autologous stem cell transplant for transformed non-Hodgkin lymphoma in the rituximab era 
Leukemia & lymphoma  2011;53(5):830-835.
The impact of rituximab on outcome of high dose therapy and autologous stem cell transplantation (HD-ASCT) for transformed NHL has not been previously described. We analyzed eighteen consecutive patients with indolent NHL who transformed to diffuse large B-cell lymphoma (DLBCL), received rituximab-containing therapy either before or after transformation and underwent subsequent HD-ASCT. With a median follow-up of 40 months, the 2-year PFS was 59% and the 2-year OS was 82%. Six patients did not receive rituximab pre-transformation; this group had a significantly better PFS at 2 years post HD-ASCT compared to 12 patients who were exposed to rituximab pre-transformation (p=0.03). HD-ASCT remains an effective therapeutic option for transformed NHL in the rituximab era. However, patients exposed to rituximab pre-transformation appear to have inferior HD-ASCT outcomes, and thus may benefit from novel conditioning and maintenance regimens in the setting of HD-ASCT.
PMCID: PMC3653616  PMID: 22023518
HD-ASCT; Transformed NHL; Rituximab; Transplant
9.  Integrated nonlinear optical imaging microscope for on-axis crystal detection and centering at a synchrotron beamline 
Journal of Synchrotron Radiation  2013;20(Pt 4):531-540.
Nonlinear optical (NLO) instrumentation has been integrated with synchrotron X-ray diffraction for combined single-platform analysis, examining the viability of NLO microscopy as an alternative to the conventional X-ray raster scan for the purposes of sample centering. Second-harmonic generation microscopy and two-photon excited ultraviolet fluorescence microscopy were evaluated for crystal detection, and assessed by X-ray raster scanning.
Nonlinear optical (NLO) instrumentation has been integrated with synchrotron X-ray diffraction (XRD) for combined single-platform analysis, initially targeting applications for automated crystal centering. Second-harmonic-generation microscopy and two-photon-excited ultraviolet fluorescence microscopy were evaluated for crystal detection and assessed by X-ray raster scanning. Two optical designs were constructed and characterized; one positioned downstream of the sample and one integrated into the upstream optical path of the diffractometer. Both instruments enabled protein crystal identification with integration times between 80 and 150 µs per pixel, representing a ∼103–104-fold reduction in the per-pixel exposure time relative to X-ray raster scanning. Quantitative centering and analysis of phenylalanine hydroxylase from Chromobacterium violaceum cPAH, Trichinella spiralis deubiquitinating enzyme TsUCH37, human κ-opioid receptor complex kOR-T4L produced in lipidic cubic phase (LCP), intimin prepared in LCP, and α-cellulose samples were performed by collecting multiple NLO images. The crystalline samples were characterized by single-crystal diffraction patterns, while α-cellulose was characterized by fiber diffraction. Good agreement was observed between the sample positions identified by NLO and XRD raster measurements for all samples studied.
PMCID: PMC3682636  PMID: 23765294
XRD; NLO; SHG; SONICC; centering; protein; TPE-UVF; microscopy; LCP; two-photon
10.  Late Relapses Following High-Dose Autologous Stem Cell Transplantation (HD-ASCT) for Hodgkin Lymphoma (HL) in the ABVD Therapeutic era 
Salvage chemotherapy followed by high dose autologous stem cell transplantation (HD-ASCT) is the standard of care for patients who have relapsed or refractory Hodgkin Lymphoma (HL). Few trials have had long-term follow-up post HD-ASCT in the ABVD era of treatment. We reviewed 95 consecutive patients who received HD-ASCT for relapsed or refractory HL following ABVD failure between 1990 and 2006 at the University of Rochester. Median follow-up for survivors was 8.2 years. All patients received HD-ASCT following up-front ABVD (or equivalent) failure. At 5 years, overall survival (OS) and event-free survival (EFS) were 54% and 37%, respectively. In total, 54 patients have died; 37 of these patients died directly of HL. Notably, there were 19 deaths > 3 years post HD-ASCT and 13 of these late deaths are directly attributable to HL. Furthermore, there were 51 documented relapses, 9 of which occurred >3 years post HD-ASCT. In contrast to other studies, we did not observe a plateau in EFS following transplantation. Patients appear to be at continuous risk of recurrence beyond 3 years after HD-ASCT. Our results emphasize the importance of long-term follow-up for both toxicity and recurrence, and have important implications in defining success of post-transplant maintenance strategies.
PMCID: PMC3269502  PMID: 21871246
Hodgkin lymphoma; hematopoietic stem cells; late effects of therapy; relapsed and refractory disease; HD-ASCT
11.  AMASS: Algorithm for MSI Analysis by Semi-supervised Segmentation 
Journal of proteome research  2011;10(10):4734-4743.
Mass Spectrometric Imaging (MSI) is a molecular imaging technique that allows the generation of 2D ion density maps for a large complement of the active molecules present in cells and sectioned tissues. Automatic segmentation of such maps according to patterns of co-expression of individual molecules can be used for discovery of novel molecular signatures (molecules that are specifically expressed in particular spatial regions). However, current segmentation techniques are biased towards the discovery of higher abundance molecules and large segments; they allow limited opportunity for user interaction and validation is usually performed by similarity to known anatomical features.
We describe here a novel method, AMASS (Algorithm for MSI Analysis by Semi-supervised Segmentation). AMASS relies on the discriminating power of a molecular signal instead of its intensity as a key feature, uses an internal consistency measure for validation, and allows significant user interaction and supervision as options. An automated segmentation of entire leech embryo data images resulted in segmentation domains congruent with many known organs, including heart, CNS ganglia, nephridia, nephridiopores, and lateral and ventral regions, each with a distinct molecular signature. Likewise, segmentation of a rat brain MSI slice data set yielded known brain features, and provided interesting examples of co-expression between distinct brain regions. AMASS represents a new approach for the discovery of peptide masses with distinct spatial features of expression.
PMCID: PMC3190602  PMID: 21800894
Mass Spectrometry Imaging; MALDI Imaging; Segmentation
12.  Chromosomal translocations are guided by the spatial organization of the genome 
Cell  2012;148(5):908-921.
The extent to which the three dimensional organization of the genome contributes to chromosomal translocations is an important question in cancer genomics. We now have generated a high resolution Hi-C spatial organization map of the G1-arrested mouse pro-B cell genome and mapped translocations from target DNA double strand breaks (DSBs) within it via high throughput genome-wide translocation sequencing. RAG endonuclease-cleaved antigen-receptor loci are dominant translocation partners for target DSBs regardless of genomic position, reflecting high frequency DSBs at these loci and their co-localization in a fraction of cells. To directly assess spatial proximity contributions, we normalized genomic DSBs via ionizing-radiation. Under these conditions, translocations were highly enriched in cis along single chromosomes containing target DSBs and within other chromosomes and sub-chromosomal domains in a manner directly related to pre-existing spatial proximity. Our studies reveal the power of combining two high-throughput genomic methods to address long-standing questions in cancer biology.
PMCID: PMC3320767  PMID: 22341456
Translocations; 3D nuclear organization; DNA double-strand breaks; genome stability
13.  Automated sample-scanning methods for radiation damage mitigation and diffraction-based centering of macromolecular crystals 
Journal of Synchrotron Radiation  2011;18(Pt 5):717-722.
Two sample-scanning features have been implemented for the macromolecular crystallography beamlines at APS sector 23: automated diffraction-based rastering employing multiple polygon-shaped two-dimensional grids overlaid on a sample to locate and center small and invisible crystals or to find the best-diffracting regions in a larger crystal, and automated data collection along a three-dimensional vector to mitigate the effects of radiation damage.
Automated scanning capabilities have been added to the data acquisition software, JBluIce-EPICS, at the National Institute of General Medical Sciences and the National Cancer Institute Collaborative Access Team (GM/CA CAT) at the Advanced Photon Source. A ‘raster’ feature enables sample centering via diffraction scanning over two-dimensional grids of simple rectangular or complex polygonal shape. The feature is used to locate crystals that are optically invisible owing to their small size or are visually obfuscated owing to properties of the sample mount. The raster feature is also used to identify the best-diffracting regions of large inhomogeneous crystals. Low-dose diffraction images taken at grid positions are automatically processed in real time to provide a quick quality ranking of potential data-collection sites. A ‘vector collect’ feature mitigates the effects of radiation damage by scanning the sample along a user-defined three-dimensional vector during data collection to maximize the use of the crystal volume and the quality of the collected data. These features are integrated into the JBluIce-EPICS data acquisition software developed at GM/CA CAT where they are used in combination with a robust mini-beam of rapidly changeable diameter from 5 µm to 20 µm. The powerful software–hardware combination is being applied to challenging problems in structural biology.
PMCID: PMC3161817  PMID: 21862850
macromolecular crystallography; beamline automation; data acquisition; high-throughput crystallography; crystal centering; radiation damage; rastering
14.  Fast fluorescence techniques for crystallography beamlines 
Journal of Applied Crystallography  2011;44(Pt 4):772-778.
On-the-fly adaptive edge scanning and shuttle on-the-fly rastering fluorescence techniques have been developed to improve the efficiency of macromolecular crystallography beamlines.
This paper reports on several developments of X-ray fluorescence techniques for macromolecular crystallography recently implemented at the National Institute of General Medical Sciences and National Cancer Institute beamlines at the Advanced Photon Source. These include (i) three-band on-the-fly energy scanning around absorption edges with adaptive positioning of the fine-step band calculated from a coarse pass; (ii) on-the-fly X-ray fluorescence rastering over rectangular domains for locating small and invisible crystals with a shuttle-scanning option for increased speed; (iii) fluorescence rastering over user-specified multi-segmented polygons; and (iv) automatic signal optimization for reduced radiation damage of samples.
PMCID: PMC3247932  PMID: 21808424
macromolecular crystallography; beamline automation; data acquisition; high-throughput crystallography; X-ray fluorescence; multi-wavelength anomalous diffraction
15.  The Use of Chelated Radionuclide (Samarium-153-Ethylenediaminetetramethylenephosphonate) to Modulate Phenotype of Tumor Cells and Enhance T Cell–Mediated Killing 
Exposing human tumor cells to sublethal doses of external beam radiation up-regulates expression of tumor antigen and accessory molecules, rendering tumor cells more susceptible to killing by antigen-specific CTLs. This study explored the possibility that exposure to palliative doses of a radiopharmaceutical agent could alter the phenotype of tumor cells to render them more susceptible to T cell – mediated killing.
Experimental Design
Here, 10 human tumor cell lines (4 prostate, 2 breast, and 4 lung) were exposed to increasing doses of the radiopharmaceutical samarium-153-ethylenediaminetetrame-thylenephosphonate (153Sm-EDTMP) used in cancer patients to treat pain due to bone metastasis. Fluorescence-activated cell sorting analysis and quantitative real-time PCR analysis for expression of five surface molecules and several tumor-associated antigens involved in prostate cancer were done. LNCaP human prostate cancer cells were exposed to153Sm-EDTMP and incubated with tumor-associated antigen-specific CTL in a CTL killing assay to determine whether exposure to 153Sm-EDTMP rendered LNCaP cells more susceptible to T cell – mediated killing.
Tumor cells up-regulated the surface molecules Fas (100% of cell lines up-regulated Fas), carcinoembryonic antigen (90%), mucin-1 (60%), MHC class I (50%), and intercellular adhesion molecule-1 (40%) in response to 153Sm-EDTMP. Quantitative real-time PCR analysis revealed additional up-regulated tumor antigens. Exposure to 153Sm-EDTMP rendered LNCaP cells more susceptible to killing by CTLs specific for prostate-specific antigen, carcinoembryonic antigen, and mucin-1.
Doses of 153Sm-EDTMP equivalent to palliative doses delivered to bone alter the phenotype of tumor cells, suggesting that153Sm-EDTMP may work synergistically with immuno-therapy to increase the susceptibility of tumor cells to CTL killing.
PMCID: PMC3407883  PMID: 18594006
16.  JBluIce–EPICS control system for macromolecular crystallography 
A fast, user-friendly and easily extensible beamline-control system based on a combination of Java Eclipse RCP and EPICS and featuring a user interface similar to that of the SSRL BluIce has been developed at the GM/CA-CAT macromolecular crystallography beamlines in Sector 23 of the Advanced Photon Source.
The trio of macromolecular crystallography beamlines constructed by the General Medicine and Cancer Institutes Collaborative Access Team (GM/CA-CAT) in Sector 23 of the Advanced Photon Source (APS) have been in growing demand owing to their outstanding beam quality and capacity to measure data from crystals of only a few micrometres in size. To take full advantage of the state-of-the-art mechanical and optical design of these beamlines, a significant effort has been devoted to designing fast, convenient, intuitive and robust beamline controls that could easily accommodate new beamline developments. The GM/CA-CAT beamline controls are based on the power of EPICS for distributed hardware control, the rich Java graphical user interface of Eclipse RCP and the task-oriented philosophy as well as the look and feel of the successful SSRL BluIce graphical user interface for crystallography. These beamline controls feature a minimum number of software layers, the wide use of plug-ins that can be written in any language and unified motion controls that allow on-the-fly scanning and optimization of any beamline com­ponent. This paper describes the ways in which BluIce was combined with EPICS and converted into the Java-based JBluIce, discusses the solutions aimed at streamlining and speeding up operations and gives an overview of the tools that are provided by this new open-source control system for facilitating crystallo­graphic experiments, especially in the field of microcrystallo­graphy.
PMCID: PMC3046456  PMID: 21358048
macromolecular crystallography; beamline automation; data acquisition; high-throughput crystallography
17.  β1 integrin establishes endothelial cell polarity and arteriolar lumen formation via a Par3-dependent mechanism 
Developmental cell  2010;18(1):39-51.
Maintenance of single layered endothelium, squamous endothelial cell shape, and formation of a patent vascular lumen all require defined endothelial cell polarity. Loss of β1 integrin (Itgb1) in nascent endothelium leads to disruption of arterial endothelial cell polarity and lumen formation. The loss of polarity is manifested as cuboidal shaped endothelial cells, dysregulated levels and mis-localization of normally polarized cell-cell adhesion molecules, as well as decreased expression of the polarity gene Par3 (pard3). β1 integrin and Par3 are both localized to the endothelial layer, with preferential expression of Par3 in arterial endothelium. Luminal occlusion is also exclusively noted in arteries, and is partially rescued by replacement of Par3 protein in β1 deficient vessels. Combined, our findings demonstrate that β1 integrin functions upstream of Par3 as part of a molecular cascade required for endothelial cell polarity and lumen formation.
PMCID: PMC3178410  PMID: 20152176
β1 integrin; Itgb1; endothelium; VE-cadherin; vasculature; lumen formation; polarity; Par3; pard3; Cre; lox
18.  Normalization in MALDI-TOF imaging datasets of proteins: practical considerations 
Normalization is critically important for the proper interpretation of matrix-assisted laser desorption/ionization (MALDI) imaging datasets. The effects of the commonly used normalization techniques based on total ion count (TIC) or vector norm normalization are significant, and they are frequently beneficial. In certain cases, however, these normalization algorithms may produce misleading results and possibly lead to wrong conclusions, e.g. regarding to potential biomarker distributions. This is typical for tissues in which signals of prominent abundance are present in confined areas, such as insulin in the pancreas or β-amyloid peptides in the brain. In this work, we investigated whether normalization can be improved if dominant signals are excluded from the calculation. Because manual interaction with the data (e.g., defining the abundant signals) is not desired for routine analysis, we investigated two alternatives: normalization on the spectra noise level or on the median of signal intensities in the spectrum. Normalization on the median and the noise level was found to be significantly more robust against artifact generation compared to normalization on the TIC. Therefore, we propose to include these normalization methods in the standard “toolbox” of MALDI imaging for reliable results under conditions of automation.
Electronic supplementary material
The online version of this article (doi:10.1007/s00216-011-4929-z) contains supplementary material, which is available to authorized users.
PMCID: PMC3124646  PMID: 21479971
Bioanalytical methods; Biological samples; Genomics/proteomics; MALDI imaging; Normalization; Data processing
19.  The Role of Mechanistic Factors in Promoting Chromosomal Translocations Found in Lymphoid and Other Cancers 
Advances in immunology  2010;106:93-133.
Recurrent chromosomal abnormalities, especially chromosomal translocations, are strongly associated with certain subtypes of leukemia, lymphoma and solid tumors. The appearance of particular translocations or associated genomic alterations can be important indicators of disease prognosis, and in some cases, certain translocations may indicate appropriate therapy protocols. To date, most of our knowledge about chromosomal translocations has derived from characterization of the highly selected recurrent translocations found in certain cancers. Until recently, mechanisms that promote or suppress chromosomal translocations, in particular, those responsible for their initiation, have not been addressed. For translocations to occur, two distinct chromosomal loci must be broken, brought together (synapsed) and joined. Here, we discuss recent findings on processes and pathways that influence the initiation of chromosomal translocations, including the generation fo DNA double strand breaks (DSBs) by general factors or in the context of the Lymphocyte-specific V(D)J and IgH class-switch recombination processes. We also discuss the role of spatial proximity of DSBs in the interphase nucleus with respect to how DSBs on different chromosomes are justaposed for joining. In addition, we discuss the DNA DSB response and its role in recognizing and tethering chromosomal DSBs to prevent translocations, as well as potential roles of the classical and alternative DSB end-joining pathways in suppressing or promoting translocations. Finally, we discuss the potential roles of long range regulatory elements, such as the 3’IgH enhancer complex, in promoting the expression of certain translocations that are frequent in lymphomas and, thereby, contributing to their frequent appearance in tumors.
PMCID: PMC3073861  PMID: 20728025
20.  Impact of left ventricular lead position on the efficacy of cardiac resynchronisation therapy: a two‐dimensional strain echocardiography study 
Heart  2007;93(10):1197-1203.
Definition of the optimal left ventricular (LV) lead position in cardiac resynchronisation therapy (CRT) is desirable.
To define the optimal LV lead position in CRT and assess the effectiveness of CRT depending on the LV lead position using new myocardial deformation imaging.
Myocardial deformation imaging based on tracking of acoustic tissue pixels in two‐dimensional echocardiographic images (EchoPAC, GE ultrasound) was performed in 47 patients with heart failure at baseline and during CRT. In a 36‐segment LV model the segment with the latest peak systolic circumferential strain before CRT was determined. The segment with maximal temporal difference in peak systolic circumferential strain on CRT compared with before CRT was assumed to be the LV lead position. The optimal LV lead position was defined as concurrence or immediate neighbouring of the segment with the latest contraction before CRT and those with assumed LV lead location.
25 patients had optimal and 22 non‐optimal LV lead positions. Before CRT, the LV ejection fraction (EF) and peak oxygen consumption (Vo2max) were similar in patients with optimal and non‐optimal LV lead positions (mean (SD) EF = 31.4 (6.1)% vs 30.3 (6.5)% and Vo2max = 14.2 (1.8) vs 14.0 (2.1) ml/min/kg, respectively). At 3 months on CRT, EF increased by 9 (2)% vs 5 (3)% and Vo2max by 2.0 (0.8) vs 1.1 (0.5) ml/min/kg in the optimal vs non‐optimal LV lead position groups, respectively (both p<0.001).
Concordance of the LV lead site and location of the latest systolic contraction before CRT results in greater improvement in EF and cardiopulmonary workload than the non‐optimal LV lead position.
PMCID: PMC2000938  PMID: 17309913
echocardiography; heart failure; pacing
21.  The urate-lowering efficacy and safety of febuxostat in the treatment of the hyperuricemia of gout: the CONFIRMS trial 
The purpose of this study was to compare urate-lowering (UL) efficacy and safety of daily febuxostat and allopurinol in subjects with gout and serum urate (sUA) ≥ 8.0 mg/dL in a six-month trial.
Subjects (n = 2,269) were randomized to febuxostat 40 mg or 80 mg, or allopurinol 300 mg (200 mg in moderate renal impairment). Endpoints included the proportion of all subjects with sUA <6.0 mg/dL and the proportion of subjects with mild/moderate renal impairment and sUA <6.0 mg/dL. Safety assessments included blinded adjudication of each cardiovascular (CV) adverse event (AE) and death.
Comorbidities included: renal impairment (65%); obesity (64%); hyperlipidemia (42%); and hypertension (53%). In febuxostat 40 mg, febuxostat 80 mg, and allopurinol groups, primary endpoint was achieved in 45%, 67%, and 42%, respectively. Febuxostat 40 mg UL was statistically non-inferior to allopurinol, but febuxostat 80 mg was superior to both (P < 0.001). Achievement of target sUA in subjects with renal impairment was also superior with febuxostat 80 mg (72%; P < 0.001) compared with febuxostat 40 mg (50%) or allopurinol (42%), but febuxostat 40 mg showed greater efficacy than allopurinol (P = 0.021). Rates of AEs did not differ across treatment groups. Adjudicated (APTC) CV event rates were 0.0% for febuxostat 40 mg and 0.4% for both febuxostat 80 mg and allopurinol. One death occurred in each febuxostat group and three in the allopurinol group.
Urate-lowering efficacy of febuxostat 80 mg exceeded that of febuxostat 40 mg and allopurinol (300/200 mg), which were comparable. In subjects with mild/moderate renal impairment, both febuxostat doses were more efficacious than allopurinol and equally safe. At the doses tested, safety of febuxostat and allopurinol was comparable.
Clinical Trial Registration
PMCID: PMC2888216  PMID: 20370912
22.  Mini-beam collimator enables microcrystallography experiments on standard beamlines 
Journal of Synchrotron Radiation  2009;16(Pt 2):217-225.
A ‘mini-beam’ apparatus has been developed that conditions the size of an X-ray beam to 5 µm. The design of the apparatus and the characterization of the focal size and flux are presented.
The high-brilliance X-ray beams from undulator sources at third-generation synchrotron facilities are excellent tools for solving crystal structures of important and challenging biological macromolecules and complexes. However, many of the most important structural targets yield crystals that are too small or too inhomogeneous for a ‘standard’ beam from an undulator source, ∼25–50 µm (FWHM) in the vertical and 50–100 µm in the horizontal direction. Although many synchrotron facilities have microfocus beamlines for other applications, this capability for macromolecular crystallography was pioneered at ID-13 of the ESRF. The National Institute of General Medical Sciences and National Cancer Institute Collaborative Access Team (GM/CA-CAT) dual canted undulator beamlines at the APS deliver high-intensity focused beams with a minimum focal size of 20 µm × 65 µm at the sample position. To meet growing user demand for beams to study samples of 10 µm or less, a ‘mini-beam’ apparatus was developed that conditions the focused beam to either 5 µm or 10 µm (FWHM) diameter with high intensity. The mini-beam has a symmetric Gaussian shape in both the horizontal and vertical directions, and reduces the vertical divergence of the focused beam by 25%. Significant reduction in background was achieved by implementation of both forward- and back-scatter guards. A unique triple-collimator apparatus, which has been in routine use on both undulator beamlines since February 2008, allows users to rapidly interchange the focused beam and conditioned mini-beams of two sizes with a single mouse click. The device and the beam are stable over many hours of routine operation. The rapid-exchange capability has greatly facilitated sample screening and resulted in several structures that could not have been obtained with the larger focused beam.
PMCID: PMC2725011  PMID: 19240333
mini-beam; microbeam; microdiffraction; macromolecular crystallography
23.  Fate tracing reveals the endothelial origin of hematopoietic stem cells 
Cell stem cell  2008;3(6):625-636.
Hematopoietic stem cells (HSCs) originate within the aorta-gonado-mesonephros (AGM) region of the midgestation embryo, but the cell type responsible for their emergence is unknown since critical hematopoietic factors are expressed in both the AGM endothelium and its underlying mesenchyme. Here we employ a temporally restricted genetic tracing strategy to selectively label the endothelium, and separately its underlying mesenchyme, during AGM development. Lineage tracing endothelium, via an inducible VE-cadherin Cre line, reveals that the endothelium is capable of HSC emergence. The endothelial progeny migrate to the fetal liver, and later to the bone marrow, are capable of expansion, self-renewal, and multi-lineage hematopoietic differentiation. HSC capacity is exclusively endothelial, as ex vivo analyses demonstrate lack of VE-cadherin Cre induction in circulating and fetal liver hematopoietic populations. Moreover, AGM mesenchyme, as selectively traced via a myocardin Cre line, is incapable of hematopoiesis. Our genetic tracing strategy therefore reveals an endothelial origin of HSCs.
PMCID: PMC2631552  PMID: 19041779
Hematopoietic stem cells; HSC; aorta-gonado-mesonephros; AGM; VE-cadherin; Cre-recombinase; hemogenic endothelium; hematopoiesis; lineage tracing; tamoxifen
24.  Molecular assays for the detection of microRNAs in prostate cancer 
Molecular Cancer  2009;8:17.
MicroRNAs (miRNAs) are small non-coding RNAs (about 21 to 24 nucleotides in length) that effectively reduce the translation of their target mRNAs. Several studies have shown miRNAs to be differentially expressed in prostate cancer, many of which are found in fragile regions of chromosomes. Expression profiles of miRNAs can provide information to separate malignancies based upon stage, progression and prognosis. Here we describe research prototype assays that detect a number of miRNA sequences with high analytical sensitivity and specificity, including miR-21, miR-182, miR-221 and miR-222, which were identified through expression profiling experiments with prostate cancer specimens. The miRNAs were isolated, amplified and quantified using magnetic bead-based target capture and a modified form of Transcription-Mediated Amplification (TMA).
Analytical sensitivity and specificity were demonstrated in model system experiments using synthetic mature microRNAs or in vitro miRNA hairpin precursor transcripts. Research prototype assays for miR-21, miR-182, miR-221 and miR-222 provided analytical sensitivities ranging from 50 to 500 copies of target per reaction in sample transport medium. Specific capture and detection of mature miR-221 from complex samples was demonstrated in total RNA isolated from human prostate cancer cell lines and xenografts.
Research prototype real-time TMA assays for microRNAs provide accurate and reproducible quantitation using 10 nanograms of input total RNA. These assays can also be used directly with tissue specimens, without the need for a preanalytic RNA isolation step, and thus provide a high-throughput method of microRNA profiling in clinical specimens.
PMCID: PMC2656451  PMID: 19267923
25.  Biologic activity and safety of belimumab, a neutralizing anti-B-lymphocyte stimulator (BLyS) monoclonal antibody: a phase I trial in patients with systemic lupus erythematosus 
Arthritis Research & Therapy  2008;10(5):R109.
This trial evaluated the safety, biologic activity, and pharmacokinetics of belimumab, a fully human monoclonal antibody that inhibits the biologic activity of the soluble form of the essential B-cell survival factor B-lymphocyte stimulator (BLyS) in patients with systemic lupus erythematosus (SLE).
Seventy patients with mild-to-moderate SLE were enrolled in a phase I, double-blind, randomized study and treated with placebo (n = 13) or belimumab (n = 57) at four different doses (1.0, 4.0, 10, and 20 mg/kg) as a single infusion or two infusions 21 days apart. Patients were followed for 84 to 105 days to assess adverse events, pharmacokinetics, peripheral blood B-cell counts, serology, and SLE disease activity. Data from the study were summarized using descriptive statistics. χ2 type tests were used to analyze discrete variables. The Kruskal-Wallis test, the Wilcoxon test, and the analysis of covariance were used to analyze the continuous variables, as appropriate. The analysis was performed on all randomized patients who received study agent.
The incidences of adverse events and laboratory abnormalities were similar among the belimumab and placebo groups. Belimumab pharmacokinetics were linear across the 1.0 to 20 mg/kg dose range. Long terminal elimination half-life (8.5 to 14.1 days), slow clearance (7 ml/day per kg), and small volume of distribution (69 to 112 ml/kg) were consistent with a fully human antibody. Significant reductions in median percentages of CD20+ B cells were observed in patients treated with a single dose of belimumab versus placebo (day 42: P = 0.0042; and day 84: P = 0.0036) and in patients treated with two doses of belimumab versus placebo (day 105: P = 0.0305). SLE disease activity did not change after one or two doses of belimumab.
Belimumab was well tolerated and reduced peripheral B-cell levels in SLE patients. These data support further studies of belimumab in autoimmune disorders.
Trial Registration
NCT00657007 [].
PMCID: PMC2592791  PMID: 18786258

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