Molecular regulation of the PAI‐1 gene by hypoxia: contributions of Egr‐1, HIF‐1 α, and C/EBPα

Hypoxia, as occurs during tissue ischemia, tips the natural anticoagulant/procoagulant balance of the endovascular wall to favor activation of coagulation. Plasminogen activator inhibitor‐1 (PAI‐1) is an important factor suppressing fibrinolysis under conditions of low oxygen tension. We previously reported that hypoxia induced PAI‐1 mRNA and antigen expression in murine macrophages secondary to increased de novo transcription as well as increased mRNA stability. We now show in RAW264.7 murine macrophages that the transcription factors early growth response gene‐1 (Egr‐1), hypoxia‐inducible factor‐1α (HIF‐1α), and CCAAT/enhancer binding protein α (C/EBPα) are quickly activated in hypoxia and are responsible for transcription and expression of PAI‐1. Murine PAI‐1 promoter constructs, including Egr, HIF‐1α, and/or C/EBPα binding sites, were transfected into RAW 264.7 murine macrophages. To identify the relative importance of each of these putative hypoxia‐responsive elements, cells were exposed to normobaric hypoxia, and transcriptional activity was recorded. At 16 h of hypoxic exposure, murine PAI‐1 promoter deletion constructs that included Egr, HIF‐1α, and/or C/EBPα binding sites demonstrated increased tran‐scriptional activity. Mutation of each of these three murine PAI‐1 promoter sites (or a combination of them) resulted in a marked reduction in hypoxia sensitivity as detected by transcriptional analysis. Functional data obtained using 32P‐labeled Egr, HIF‐1 α response element (HRE), and C/EBPα oligonucleotides revealed induction of DNA binding activity in nuclear extracts from hypoxic RAW cells, with supershift analysis confirming activation of Egr‐1, HIF‐1 α, or C/EBPα. ChIP analysis confirmed the authenticity of these interactions as each of these transcription factors binds to chromatin under hypoxic conditions. Further, the induction of PAI‐1 by Egr‐1, HIF‐1 α, or C/EBPα was replicated in primary peritoneal macrophages. These data suggest that although HIF‐1 α appears to dominate the PAI‐1 transcriptional response in hyp‐oxia, Egr‐1 and C/EBPα greatly augment this response and can do so independent of HIF‐1α or each other. These studies are relevant to ischemic up‐regulation of the PAI‐1 gene and consequent accrual of micro‐vascular thrombus under ischemic conditions.—Liao, H., Hyman, M. C., Lawrence, D. A., Pinsky, D. J. Molecular regulation of the PAI‐1 gene by hypoxia: contributions of Egr‐1, HIF‐1α, and C/EBPα. FASEB J. 21, 935–949 (2007)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/154298/1/fsb2fj066285com.pd

Cell proliferation and differentiation kinetics during spermatogenesis in Hydra carnea

Spermatogenesis inHydra carnea was investigated. The cell proliferation and differentiation kinetics of intermediates in the spermatogenesis pathway were determined, using quantitative determinations of cell abundance, pulse and continuous labelling with3H-thymidine and nuclear DNA measurements. Testes develop in the ectoderm of male hydra as a result of interstitial cell proliferation. Gonial stem cells and proliferating spermatogonia have cell cycles of 28 h and 22 h, respectively. Stem cells undergo four, five or six cell divisions prior to meiosis which includes a premeiotic S+G2 phase of 20 h followed by a long meiotic prophase (22 h). Spermatid differentiation requires 12–29 h. When they first appear, testes contain only proliferating spermatogonia; meiotic and postmeiotic cells appear after 2 and 3 days, respectively and release of mature sperm begins after 4 days. Mature testes produce about 27,000 sperm per day over a period of 4–6 days: about 220 gonial stem cells per testis are required to support this level of sperm differentiation. Further results indicate that somatic (e.g. nematocyte) differentiation does not occur in testes although it continues normally in ectodermal tissue outside testes. Our results support the hypothesis that spermatogenesis is controlled locally in regions of the ectoderm where testes develop

Dynamics and Transport in Random Antiferromagnetic Spin Chains

We present the first results on the low-frequency dynamical and transport properties of random antiferromagnetic spin chains at low temperature ($T$). We obtain the momentum and frequency dependent dynamic structure factor in the Random Singlet (RS) phases of both spin-1/2 and spin-1 chains, as well as in the Random Dimer phase of spin-1/2 chains. We also show that the RS phases are unusual `spin-metals' with divergent low-frequency conductivity at T=0, and follow the spin conductivity through `metal-insulator' transitions tuned by the strength of dimerization or Ising anisotropy in the spin-1/2 case, and by the strength of disorder in the spin-1 case.Comment: 4 pages (two-column format). Presentation substantially revised to accomodate new result

Effect of a Physician Uncertainty Reduction Intervention on Blood Pressure in Uncontrolled Hypertensives-A Cluster Randomized Trial

BACKGROUND: Clinical inertia, provider failure to appropriately intensify treatment, is a major contributor to uncontrolled blood pressure (BP). Some clinical inertia may result from physician uncertainty over the patient’s usual BP, adherence, or value of continuing efforts to control BP through lifestyle changes. OBJECTIVE: To test the hypothesis that providing physicians with uncertainty reduction tools, including 24-h ambulatory BP monitoring, electronic bottle cap monitoring, and lifestyle assessment and counseling, will lead to improved BP control. DESIGN: Cluster randomized trial with five intervention clinics (IC) and five usual care clinics (UCC). SETTING: Six public and 4 private primary care clinics. PARTICIPANTS: A total of 665 patients (63 percent African American) with uncontrolled hypertension (BP ≥140 mmHg/90 mmHg or ≥130/80 mmHg if diabetic). INTERVENTIONS: An order form for uncertainty reduction tools was placed in the IC participants’ charts before each visit and results fed back to the provider. OUTCOME MEASURES: Percent with controlled BP at last visit. Secondary outcome was BP changes from baseline. RESULTS: Median follow-up time was 24 months. IC physicians intensified treatment in 81% of IC patients compared to 67% in UCC (p\u3c0.001); 35.0% of IC patients and 31.9% of UCC patients achieved control at the last recorded visit (p\u3e0.05). Multi-level mixed effects longitudinal regression modeling of SBP and DBP indicated a significant, non-linear slope difference favoring IC (p time × group interaction=0.048 for SBP and p=0.001 for DBP). The model-predicted difference attributable to intervention was −2.8 mmHg for both SBP and DBP by month 24, and −6.5 mmHg for both SBP and DBP by month 36. CONCLUSIONS: The uncertainty reduction intervention did not achieve the pre-specified dichotomous outcome, but led to lower measured BP in IC patients

MicroRNA profiling reveals marker of motor neuron disease in ALS models

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder marked by the loss of motor neurons (MNs) in the brain and spinal cord, leading to fatally debilitating weakness. Because this disease predominantly affects MNs, we aimed to characterize the distinct expression profile of that cell type to elucidate underlying disease mechanisms and to identify novel targets that inform on MN health during ALS disease time course. microRNAs (miRNAs) are short, noncoding RNAs that can shape the expression profile of a cell and thus often exhibit cell-type-enriched expression. To determine MN-enriched miRNA expression, we used Cre recombinase-dependent miRNA tagging and affinity purification in mice. By defining thein vivomiRNA expression of MNs, all neurons, astrocytes, and microglia, we then focused on MN-enriched miRNAs via a comparative analysis and found that they may functionally distinguish MNs postnatally from other spinal neurons. Characterizing the levels of the MN-enriched miRNAs in CSF harvested from ALS models of MN disease demonstrated that one miRNA (miR-218) tracked with MN loss and was responsive to an ALS therapy in rodent models. Therefore, we have used cellular expression profiling tools to define the distinct miRNA expression of MNs, which is likely to enrich future studies of MN disease. This approach enabled the development of a novel, drug-responsive marker of MN disease in ALS rodents.SIGNIFICANCE STATEMENTAmyotrophic lateral sclerosis (ALS) is a neurodegenerative disease in which motor neurons (MNs) in the brain and spinal cord are selectively lost. To develop tools to aid in our understanding of the distinct expression profiles of MNs and, ultimately, to monitor MN disease progression, we identified small regulatory microRNAs (miRNAs) that were highly enriched or exclusive in MNs. The signal for one of these MN-enriched miRNAs is detectable in spinal tap biofluid from an ALS rat model, where its levels change as disease progresses, suggesting that it may be a clinically useful marker of disease status. Furthermore, rats treated with ALS therapy have restored expression of this MN RNA marker, making it an MN-specific and drug-responsive marker for ALS rodents.</jats:p

Variable Radio Sources in the Galactic Plane

Using three epochs of VLA observations of the Galactic Plane in the first quadrant taken ~15 years apart, we have conducted a search for a population of variable Galactic radio emitters in the flux density range 1-100 mJy at 6 cm. We find 39 variable sources in a total survey area of 23.2 sq deg. Correcting for various selection effects and for the extragalactic variable population of active galactic nuclei, we conclude there are ~1.6 Galactic sources per sq deg which vary by more than 50% on a time scale of years (or shorter). We show that these sources are much more highly variable than extragalactic objects; more than 50% show variability by a factor >2 compared to <10% for extragalactic objects in the same flux density range. We also show that the fraction of variable sources increases toward the Galactic center (another indication that this is a Galactic population), and that the spectral indices of many of these sources are flat or inverted. A small number of the variables are coincident with mid-IR sources and two are coincident with X-ray emitters, but most have no known counterparts at other wavelengths. Intriguingly, one lies at the center of a supernova remnant, while another appears to be a very compact planetary nebula; several are likely to represent activity associated with star formation regions. We discuss the possible source classes which could contribute to the variable cohort and followup observations which could clarify the nature of these sources.Comment: 11 pages, 7 figures; to be published in the Astronomical Journal; data available on MAGPIS website at http://third.ucllnl.org/gps

Griffiths effects and quantum critical points in dirty superconductors without spin-rotation invariance: One-dimensional examples

We introduce a strong-disorder renormalization group (RG) approach suitable for investigating the quasiparticle excitations of disordered superconductors in which the quasiparticle spin is not conserved. We analyze one-dimensional models with this RG and with elementary transfer matrix methods. We find that such models with broken spin rotation invariance {\it generically} lie in one of two topologically distinct localized phases. Close enough to the critical point separating the two phases, the system has a power-law divergent low-energy density of states (with a non-universal continuously varying power-law) in either phase, due to quantum Griffiths singularities. This critical point belongs to the same infinite-disorder universality class as the one dimensional particle-hole symmetric Anderson localization problem, while the Griffiths phases in the vicinity of the transition are controlled by lines of strong (but not infinite) disorder fixed points terminating in the critical point.Comment: 14 pages (two-column PRB format), 9 eps figure

Dynamics and transport in random quantum systems governed by strong-randomness fixed points

We present results on the low-frequency dynamical and transport properties of random quantum systems whose low temperature ($T$), low-energy behavior is controlled by strong disorder fixed points. We obtain the momentum and frequency dependent dynamic structure factor in the Random Singlet (RS) phases of both spin-1/2 and spin-1 random antiferromagnetic chains, as well as in the Random Dimer (RD) and Ising Antiferromagnetic (IAF) phases of spin-1/2 random antiferromagnetic chains. We show that the RS phases are unusual `spin metals' with divergent low-frequency spin conductivity at T=0, and we also follow the conductivity through novel `metal-insulator' transitions tuned by the strength of dimerization or Ising anisotropy in the spin-1/2 case, and by the strength of disorder in the spin-1 case. We work out the average spin and energy autocorrelations in the one-dimensional random transverse field Ising model in the vicinity of its quantum critical point. All of the above calculations are valid in the frequency dominated regime \omega \agt T, and rely on previously available renormalization group schemes that describe these systems in terms of the properties of certain strong-disorder fixed point theories. In addition, we obtain some information about the behavior of the dynamic structure factor and dynamical conductivity in the opposite `hydrodynamic' regime $\omega < T$ for the special case of spin-1/2 chains close to the planar limit (the quantum x-y model) by analyzing the corresponding quantities in an equivalent model of spinless fermions with weak repulsive interactions and particle-hole symmetric disorder.Comment: Long version (with many additional results) of Phys. Rev. Lett. {\bf 84}, 3434 (2000) (available as cond-mat/9904290); two-column format, 33 pages and 8 figure

Infliximab Does Not Promote the Presence of Collagenolytic Bacteria in a Mouse Model of Colorectal Anastomosis

BACKGROUND: Previous work from our group has suggested a pivotal role for collagenolytic bacteria in the development of anastomotic complications. Tumor necrosis factor antagonists are a mainstay of treatment for patients with inflammatory bowel disease. The reported impact of these agents on key surgical outcomes such as anastomotic leak has been inconsistent. The objective of this study is to assess the impact of infliximab on the anastomotic microbiome in a mouse model of colon resection. DESIGN: BALB/c mice underwent colon resection with primary anastomosis. Mice were randomly assigned to receive either an intraperitoneal dose of saline (control) or 10 mg/kg of infliximab for 8 weeks prior to surgery. On postoperative day 7, the animals were sacrificed. Anastomotic tissues were analyzed by histology with TUNNEL staining as a marker of epithelial apoptosis. In order to assess compositional and functional changes of the local microbiome, anastomotic tissues were further analyzed by 16S rRNA V4 region sequencing and for the presence of collagenolytic strains that may impair anastomotic healing. The main outcome measures were microbiome community structure and the presence of collagenolytic bacteria. RESULTS: Infliximab-treated mice demonstrated an increase in epithelial apoptosis, consistent with the expected drug effect. Although infliximab modified the perianastomotic microbiome, no increase in the presence of collagenolytic bacteria was observed. CONCLUSIONS: Infliximab did not promote the emergence of collagenolytic bacteria or demonstrably impair anastomotic healing in a mouse model of colon resection and anastomosis

Variable and Transient Radio Sources in the FIRST Survey

A comprehensive search for variable and transient radio sources has been conducted using ~55,000 snapshot images of the FIRST survey. We present an analysis leading to the discovery of 1,627 variable and transient objects down to mJy levels over a wide range of timescales (few minutes to years). Variations observed range from 20% to a factor of 25. Multi-wavelength matching for counterparts reveals the diverse classes of objects exhibiting variability, ranging from nearby stars and pulsars to galaxies and distant quasars. Interestingly, more than half of the objects in the sample have either no classified counterparts or no corresponding sources at any other wavelength and require multi-wavelength follow-up observations. We discuss these classes of variables and speculate on the identity of objects that lack multi-wavelength counterparts.Comment: 63 pages, 18 encapsulated postscript figures (19 if individual subfigures are counted), 3 tables. LaTeX style file fltpage.sty used. Submitted, accepted and "in press" for publication in the Astrophysical Journal. Full electronic version of table 1 (tab1.txt) has been uploaded and can be obtained after extracting the zipped source fil