bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxidative DNA Damage Defense Systems in Avoidance of Stationary-Phase Mutagenesis in
Pseudomonas putida
Authors: Saumaa Signe , Tover Andres , Tark Mariliis , Tegova Radi , Kivisaar Maia
Published: June 2007

Oxidative damage of DNA is a source of mutation in living cells. Although all organisms have evolved mechanisms of defense against oxidative damage, little is known about these mechanisms in nonenteric bacteria, including pseudomonads. Here we have studied the involvement of oxidized guanine (GO) repair enzymes and DNA-protecting enzyme Dps in the avoidance of mutations in starving
Pseudomonas putida
. Additionally, we examined possible connections between the oxidative damage of DNA and involvement of the error-prone DNA polymerase (Pol)V homologue RulAB in stationary-phase mutagenesis in
P. putida
. Our results demonstrated that the GO repair enzymes MutY, MutM, and MutT are involved in the prevention of base substitution mutations in carbon-starved
P. putida
. Interestingly, the antimutator effect of MutT was dependent on the growth phase of bacteria. Although the lack of MutT caused a strong mutator phenotype under carbon starvation conditions for bacteria, only a twofold increased effect on the frequency of mutations was observed for growing bacteria. This indicates that MutT has a backup system which efficiently complements the absence of this enzyme in actively growing cells. The knockout of MutM affected only the spectrum of mutations but did not change mutation frequency. Dps is known to protect DNA from oxidative damage. We found that
dps
-defective
P. putida
cells were more sensitive to sudden exposure to hydrogen peroxide than wild-type cells. At the same time, the absence of Dps did not affect the accumulation of mutations in populations of starved bacteria. Thus, it is possible that the protective role of Dps becomes essential for genome integrity only when bacteria are exposed to exogenous agents that lead to oxidative DNA damage but not under physiological conditions. Introduction of the Y family DNA polymerase PolV homologue
rulAB
into
P. putida
increased the proportion of A-to-C and A-to-G base substitutions among mutations, which occurred under starvation conditions. Since PolV is known to perform translesion synthesis past damaged bases in DNA (e.g., some oxidized forms of adenine), our results may imply that adenine oxidation products are also an important source of mutation in starving bacteria.
The Oligomeric State of c Rings from Cyanobacterial F-ATP Synthases Varies from 13 to 15
Authors: Pogoryelov Denys , Reichen Christian , Klyszejko Adriana L. , Brunisholz René , Muller Daniel J. , Dimroth Peter , Meier Thomas
Published: June 2007

We isolated the c rings of F-ATP synthases from eight cyanobacterial strains belonging to four different taxonomic classes (
Chroococcales
,
Nostocales
,
Oscillatoriales
, and
Gloeobacteria
). These c rings showed different mobilities on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), probably reflecting their molecular masses. This supposition was validated with the previously characterized c
11
, c
14
, and c
15
rings, which migrated on SDS-PAGE in proportion to their molecular masses. Hence, the masses of the cyanobacterial c rings can conveniently be deduced from their electrophoretic mobilities and, together with the masses of the c monomers, allow the calculation of the c ring stoichiometries. The method is a simple and fast way to determine stoichiometries of SDS-stable c rings and hence a convenient means to unambiguously determine the ion-to-ATP ratio, a parameter reflecting the bioenergetic efficacy of F-ATP synthases. AFM imaging was used to prove the accuracy of the method and confirmed that the c ring of
Synechococcus elongatus
SAG 89.79 is a tridecameric oligomer. Despite the high conservation of the c-subunit sequences from cyanobacterial strains from various environmental groups, the stoichiometries of their c rings varied between c
13
and c
15
. This systematic study of the c-ring stoichiometries suggests that variability of c-ring sizes might represent an adaptation of the individual cyanobacterial species to their particular environmental and physiological conditions. Furthermore, the two new examples of c
15
rings underline once more that an F
1
/F
o
symmetry mismatch is not an obligatory feature of all F-ATP synthases.
pH of the Cytoplasm and Periplasm of
Escherichia coli
: Rapid Measurement by Green Fluorescent Protein Fluorimetry
Authors: Wilks Jessica C. , Slonczewski Joan L.
Published: June 2007

Cytoplasmic pH and periplasmic pH of
Escherichia coli
cells in suspension were observed with 4-s time resolution using fluorimetry of TorA-green fluorescent protein mutant 3* (TorA-GFPmut3*) and TetR-yellow fluorescent protein. Fluorescence intensity was correlated with pH using cell suspensions containing 20 mM benzoate, which equalizes the cytoplasmic pH with the external pH. When the external pH was lowered from pH 7.5 to 5.5, the cytoplasmic pH fell within 10 to 20 s to pH 5.6 to 6.5. Rapid recovery occurred until about 30 s after HCl addition and was followed by slower recovery over the next 5 min. As a control, KCl addition had no effect on fluorescence. In the presence of 5 to 10 mM acetate or benzoate, recovery from external acidification was diminished. Addition of benzoate at pH 7.0 resulted in cytoplasmic acidification with only slow recovery. Periplasmic pH was observed using TorA-GFPmut3* exported to the periplasm through the Tat system. The periplasmic location of the fusion protein was confirmed by the observation that osmotic shock greatly decreased the periplasmic fluorescence signal by loss of the protein but had no effect on the fluorescence of the cytoplasmic protein. Based on GFPmut3* fluorescence, the pH of the periplasm equaled the external pH under all conditions tested, including rapid acid shift. Benzoate addition had no effect on periplasmic pH. The cytoplasmic pH of
E. coli
was measured with 4-s time resolution using a method that can be applied to any strain construct, and the periplasmic pH was measured directly for the first time.
Cysteine Scanning Mutagenesis and Topological Mapping of the
Escherichia coli
Twin-Arginine Translocase TatC Component
Authors: Punginelli Claire , Maldonado Bárbara , Grahl Sabine , Jack Rachael , Alami Meriem , Schröder Juliane , Berks Ben C. , Palmer Tracy
Published: June 2007

The TatC protein is an essential component of the
Escherichia coli
twin-arginine (Tat) protein translocation pathway. It is a polytopic membrane protein that forms a complex with TatB, together acting as the receptor for Tat substrates. In this study we have constructed 57 individual cysteine substitutions throughout the protein. Each of the substitutions resulted in a TatC protein that was competent to support Tat-dependent protein translocation. Accessibility studies with membrane-permeant and -impermeant thiol-reactive reagents demonstrated that TatC has six transmembrane helices, rather than the four suggested by a previous study (K. Gouffi, C.-L. Santini, and L.-F. Wu, FEBS Lett. 525:65-70, 2002). Disulfide cross-linking experiments with TatC proteins containing single cysteine residues showed that each transmembrane domain of TatC was able to interact with the same domain from a neighboring TatC protein. Surprisingly, only three of these cysteine variants retained the ability to cross-link at low temperatures. These results are consistent with the likelihood that most of the disulfide cross-links are between TatC proteins in separate TatBC complexes, suggesting that TatC is located on the periphery of the complex.
Antinuclear antibody is associated with a more advanced fibrosis and lower RNA levels of hepatitis C virus in patients with chronic hepatitis C
Authors: Hsieh M-Y , Dai C-Y , Lee L-P , Huang J-F , Tsai W-C , Hou N-J , Lin Z-Y , Chen S-C , Wang L-Y , Chang W-Y , Chuang W-L , Yu M-L
Published: June 2007

Aims:

Positive serum antinuclear antibody (ANA) is present in a number of patients with chronic hepatitis C virus (HCV) infection. This study aimed to evaluate the prevalence of ANA in patients with chronic hepatitis C (CHC) and to elucidate its clinical implications in virological and histological characteristics of CHC infection.

Methods:

A total of 614 CHC patients were enrolled in this prospective, hospital-based study. The serum levels of aspartate aminotransferase, alanine aminotransferase and ANA, and HCV genotype, HCV RNA level, and histological activity index scores for liver histopathology, were determined.

Results:

The prevalence of positive ANA (titre >1:40) was 35.0%. Women had a significantly higher prevalence than men (41.2 vs 31.0%; p = 0.012). Patients positive for ANA were significantly older (mean (SD), 53.7 (10.5) vs 49.7 (11.3) years; p<0.001) and had higher mean (SD) alanine aminotransferase levels (186.9 (178.8) vs 155.50 (113.5) IU/l; p<0.001) and lower mean (SD) HCV RNA levels (5.2 (0.9) vs 5.4 (1.0) log IU/ml; p = 0.048) than those without ANA. Among 447 patients undergoing liver biopsy, those positive for ANA had a significantly higher mean (SD) fibrosis score (2.0 (1.3) vs 1.5 (1.1); p<0.001) and a higher frequency of F3–4 (69/187, 36.9% vs 50/260, 19.2%; p<0.001) than those negative for ANA. Multivariate logistic regression analyses showed that advanced fibrosis, lower HCV RNA levels and age were significant factors related to positive ANA.

Conclusion:

ANA is associated with a more advanced liver fibrosis and lower serum HCV RNA level in patients with CHC.
Morphological diagnosis of urothelial neoplasms: Figure 1
Authors: Montironi R , Mazzucchelli R , Scarpelli M , Lopez-Beltran A , Cheng L
Published: June 2007

The morphological classification and diagnosis of bladder neoplasms is summarised, with specific focus on histological typing, grading and staging. Four diagnostic categories are described on the basis of the pattern of growth of the urothelial lesions and tumours (flat, exophytic or papillary, endophytic, and invasive). The WHO 2004 classification is currently used. However, the WHO 1973 classification is still considered by many urologists and oncologists as the international standard in patient management.
The δ-opioid receptor agonist DADLE at reperfusion protects the heart through activation of pro-survival kinases via EGF receptor transactivation
Authors: Förster Karina , Kuno Atsushi , Solenkova Natalia , Felix Stephan B. , Krieg Thomas
Published: June 2007

The specific δ-opioid receptor agonist [d-Ala2-d-Leu5]enkephalin (DADLE) protects against infarction in the heart when given before ischemia. In rabbit, this protection leads to phosphorylation of the pro-survival kinases Akt and extracellular signal-regulated kinase (ERK) and is dependent on transactivation of the epidermal growth factor receptor (EGFR). DADLE reportedly protects rat hearts at reperfusion. We therefore tested whether DADLE at reperfusion could protect isolated rabbit hearts subjected to 30 min of regional ischemia and 120 min of reperfusion and whether this protection is dependent on Akt, ERK, and EGFR. DADLE (40 nM) was infused for 1 h starting 5 min before reperfusion and reduced infarct size from 31.0 ± 2.3% in the control group to 14.6 ± 1.6% ( P = 0.01). This protection was abolished by cotreatment of the metalloproteinase inhibitor (MPI) and the EGFR inhibitor AG1478. In contrast, 20 nM DADLE, although known to be protective before ischemia, failed to protect. Western blotting revealed that DADLE's protection was correlated to increase in phosphorylation of the kinases Akt and ERK1 and -2 in reperfused hearts (2.5 ± 0.5, 1.6 ± 0.2, and 2.3 ± 0.7-fold of baseline levels, P < 0.05 vs. control). The DADLE-dependent increases in Akt and ERK1/2 phosphorylation were abolished by either MPI or AG1478, confirming a signaling through the EGFR pathway. Additionally, DADLE treatment increased phosphorylation of EGFR (1.4 ± 0.2-fold, P = 0.03 vs. control). Thus the δ-opioid agonist DADLE protects rabbit hearts at reperfusion through activation of the pro-survival kinases Akt and ERK and is dependent on the transactivation of the EGFR.
Factors released from embryonic stem cells inhibit apoptosis of H9c2 cells
Authors: Singla Dinender K. , McDonald Debbie E.
Published: June 2007

Our recent study (Singla DK, Hacker TA, Ma L, Douglas PS, Sullivan R, Lyons GE, Kamp TJ, J Mol Cell Cardiol 40: 195–200, 2006) suggests that transplanted embryonic stem (ES) cells subsequent to myocardial infarction differentiate into the major cell types in the heart and improve cardiac function. However, the extent of regeneration is relatively meager compared with the observed functional improvement. The mechanisms underlying their improved function are completely unknown. In this report, we provide evidence using a cell culture model system for novel mechanisms that involve the release of cytoprotective, anti-apoptotic factor(s) from ES cells and inhibit H2O2-induced apoptosis in the rat cardiomyocyte-derived cell line H9c2. Conditioned medium (CM) from growing mouse ES cells treated with and without H2O2 was generated. Apoptosis was induced after exposure to H2O2 in H9c2 cells for 2 h followed by replacement with fresh cell culture or ES cell-CM. After 24 h, H9c2 cells treated with both ES cell-CMs demonstrated significantly decreased apoptosis, as determined by terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling staining, apoptotic ELISA, caspase-3 activity, and DNA ladder. Next, using Luminex technology, we examined the presence of antiapoptotic proteins cystatin c, osteopontin, and clusterin and anti-fibrotic, tissue inhibitor of metalloproteinase-1 (TIMP-1) in both ES cell-CMs. The levels of released factors were 2- to 170-fold higher than those in H9c2 cell-CM. Antiapoptotic effects of ES cell-CM were significantly inhibited with TIMP-1 antibody, suggesting that TIMP-1 is an important factor to inhibit apoptosis. Furthermore, we used CM from an TIMP-1-overexpressing cell line and demonstrated that H2O2-induced apoptosis in the H9c2 cells was significantly inhibited. These observations demonstrate that factors released from ES cells contain antiapoptotic factors and that the effects are mediated by TIMP-1. Moreover, these findings suggest that released factors might be useful for therapeutic applications in ischemic heart disease as well as for many other diseases.
Cardiomyocyte apoptosis in autoimmune cardiomyopathy: mediated via endoplasmic reticulum stress and exaggerated by norepinephrine
Authors: Mao Weike , Fukuoka Shuji , Iwai Chikao , Liu Jiahao , Sharma Virendra K. , Sheu Shey-Shing , Fu Michael , Liang Chang-seng
Published: June 2007

Evidence suggests that the autoimmune cardiomyopathy produced by a peptide corresponding to the sequence of the second extracellular loop of the β1-adrenergic receptor (β1-ECII) is mediated via a biologically active anti-β1-ECIIantibody, but the mechanism linking the antibody to myocyte apoptosis and cardiac dysfunction has not been well elucidated. Since the β1-ECIIautoantibody is a partial β1-agonist, we speculate that the cardiomyopathy is produced by the β1-receptor-mediated stimulation of the CaMKII-p38 MAPK-ATF6 signaling pathway and endoplasmic reticulum (ER) stress, and that excess norepinephrine (NE) exaggerates the cardiomyopathy. Rabbits were randomized to receive β1-ECIIimmunization, sham immunization, NE pellet, or β1-ECIIimmunization plus NE pellet for 6 mo. Heart function was measured by echocardiography and catheterization. Myocyte apoptosis was determined by terminal deoxytransferase-mediated dUTP nick-end labeling and caspase-3 activity, whereas CaMKII, MAPK family (JNK, p38, ERK), and ER stress signals (ATF6, GRP78, CHOP, caspase-12) were measured by Western blot, immunohistochemistry, and kinase activity assay. β1-ECIIimmunization produced progressive LV dilation, systolic dysfunction, and myocyte apoptosis. These changes were associated with activation of GRP78 and CHOP and increased cleavage of caspase-12, as well as increased CaMKII activity, increased phosphorylation of p38 MAPK, and nucleus translocation of cleaved ATF6. NE pellet produced additive effects. In addition, KN-93 and SB 203580 abolished the induction of ER stress and cell apoptosis produced by the β1-ECIIantibody in cultured neonatal cardiomyocytes. Thus ER stress occurs in autoimmune cardiomyopathy induced by β1-ECIIpeptide, and this is enhanced by increased NE and caused by activation of the β1-adrenergic receptor-coupled CaMKII, p38 MAPK, and ATF6 pathway.
Inhibition of serotonin-induced mitogenesis, migration, and ERK MAPK nuclear translocation in vascular smooth muscle cells by atorvastatin
Authors: Li Min , Liu Yinglin , Dutt Parmesh , Fanburg Barry L. , Toksoz Deniz
Published: June 2007

The HMG-CoA reductase inhibitors, statins, have pleiotropic effects which may include interference with the isoprenylation of Ras and Rho small GTPases. Statins have beneficial effects in animal models of pulmonary hypertension, although their mechanisms of action remain to be determined. Serotonin [5-hydroxytryptamine (5-HT)] is implicated in the process of pulmonary artery smooth muscle (PASM) remodeling as part of the pathophysiology of pulmonary hypertension. We examined the effect of atorvastatin on 5-HT-induced PASM cell responses. Atorvastatin dose dependently inhibits 5-HT-induced mitogenesis and migration of cultured bovine PASM cells. Inhibition by atorvastatin was reversed by mevalonate and geranylgeranylpyrophosphate (GGPP) supplement, suggesting that the statin targets a geranylgeranylated protein such as Rho. Concordantly, atorvastatin inhibits 5-HT-induced cellular RhoA activation, membrane localization, and Rho kinase-mediated phosphorylation of myosin phosphatase-1 subunit. Atorvastatin reduced activated RhoA-induced serum response factor-mediated reporter activity in HEK293 cells, indicating that atorvastatin inhibits Rho signaling, and this was reversed by GGPP. While 5-HT-induced ERK MAP and Akt kinase activation were unaffected by atorvastatin, 5-HT-induced ERK nuclear translocation was attenuated in a GGPP-dependent fashion. These studies suggest that atorvastatin inhibits 5-HT-induced PASM cell mitogenesis and migration through targeting isoprenylation which may, in part, attenuate the Rho pathway, a mechanism that may apply to statin effects on in vivo models of pulmonary hypertension.
Resistin-like molecule-β is an allergen-induced cytokine with inflammatory and remodeling activity in the murine lung
Authors: Mishra Anil , Wang Meiqin , Schlotman James , Nikolaidis Nikolaos M. , DeBrosse Charles W. , Karow Margaret L. , Rothenberg Marc E.
Published: June 2007

Resistin-like molecule (RELM)-β is a cysteine-rich cytokine implicated in insulin resistance and asthmatic responses, but its function remains an enigma. We now report that RELM-β has a role in promoting airway inflammation and lung remodeling in the mouse lung. RELM-β is strongly induced by diverse allergens and T helper type 2 (Th2) cytokines by an IL-13- and STAT6-dependent mechanism. To understand the in vivo role of RELM-β, we delivered recombinant murine RELM-β intratracheally to naïve mice. RELM-β induced dose-dependent leukocyte accumulation (most prominently involving macrophages) and goblet cell hyperplasia. The most prominent effect induced by RELM-β was increased perivascular and peribronchial collagen deposition. Mice genetically deficient in RELM-β had reduced accumulation of collagen and goblet cell hyperplasia in an experimental model of allergic airway inflammation. In vitro experiments demonstrated that RELM-β had fibroblast motogenic activity. These results identify RELM-β as a Th2-associated cytokine with potent inflammatory and remodeling activity.
Endothelial and epithelial signaling in the lung
Authors: Chatterjee Shampa , Baeter Simonida , Bhattacharya Jahar
Published: June 2007

In recent years, pulmonary research has focused increasingly on the understanding of proinflammatory endothelial and epithelial signaling pathways underlying lung injury that is well known to be associated with high morbidity and mortality. Although traditionally considered separately, current research shows considerable convergence in epithelial and endothelial signaling mechanisms. This was well emphasized in the featured topic session held during the Experimental Biology 2007 Meeting in Washington, D.C., that addressed the complex interdependence between signaling pathways in the two cellular phenotypes. Several perspectives on endothelial and epithelial signaling, as well as their contributions to pulmonary inflammation and damage, as presented and discussed in the session are summarized here.
ErbB4 regulates fetal surfactant phospholipid synthesis in primary fetal rat type II cells
Authors: Zscheppang Katja , Liu Washa , Volpe MaryAnn V. , Nielsen Heber C. , Dammann Christiane E. L.
Published: June 2007

Insufficient fetal surfactant production leads to respiratory distress syndrome among preterm infants. Neuregulin signals the onset of fetal surfactant phospholipid synthesis through formation of erbB receptor dimers. We hypothesized that erbB4 downregulation in fetal type II epithelial cells will downregulate not only fetal surfactant phospholipid synthesis, but also affect proliferation and erbB receptor localization. We tested these hypotheses using small interfering RNA (siRNA) directed against the erbB4 gene to silence erbB4 receptor function in cultures of primary day 19 fetal rat lung type II cells. ErbB4 siRNA treatment inhibited erbB4 receptor protein expression, fibroblast-conditioned medium induced erbB4 phosphorylation, and fetal surfactant phospholipid synthesis. Cell proliferation, measured as thymidine incorporation, was also inhibited by erbB4 siRNA treatment. Downregulation of erbB4 receptor protein changed erbB1 localization at baseline and after stimulation, as determined by confocal microscopy and subcellular fractionation. We conclude that erbB4 is an important receptor in the control of fetal lung type II cell maturation.
Effect of chemical stabilizers of hypoxia-inducible factors on early lung development
Authors: Groenman Freek A. , Rutter Martin , Wang Jinxia , Caniggia Isabella , Tibboel Dick , Post Martin
Published: June 2007

Low oxygen stimulates pulmonary vascular development and airway branching and involves hypoxia-inducible factor (HIF). HIF is stable and initiates expression of angiogenic factors under hypoxia, whereas normoxia triggers hydroxylation of the HIF-1α subunit by prolyl hydroxylases (PHDs) and subsequent degradation. Herein, we investigated whether chemical stabilization of HIF-1α under normoxic (20% O2) conditions would stimulate vascular growth and branching morphogenesis in early lung explants. Tie2-LacZ (endothelial LacZ marker) mice were used for visualization of the vasculature. Embryonic day 11.5 (E11.5) lung buds were dissected and cultured in 20% O2 in the absence or presence of cobalt chloride (CoCl2, a hypoxia mimetic), dimethyloxalylglycine (DMOG; a nonspecific inhibitor of PHDs), or desferrioxamine (DFO; an iron chelator). Vascularization was assessed by X-gal staining, and terminal buds were counted. The fine vascular network surrounding the developing lung buds seen in control explants disappeared in CoCl2- and DFO-treated explants. Also, epithelial branching was reduced in the explants treated with CoCl2 and DFO. In contrast, DMOG inhibited branching but stimulated vascularization. Both DFO and DMOG increased nuclear HIF-1α protein levels, whereas CoCl2 had no effect. Since HIF-1α induces VEGF expression, the effect of SU-5416, a potent VEGF receptor (VEGFR) blocker, on early lung development was also investigated. Inhibition of VEGFR2 signaling in explants maintained under hypoxic (2% O2) conditions completely abolished vascularization and slightly decreased epithelial branching. Taken together, the data suggest that DMOG stabilization of HIF-1α during early development leads to a hypervascular lung and that airway branching proceeds without the vasculature, albeit at a slower rate.
Beyond Pleasure: Emotion Activity Affects the Relationship Between Attitudes and Behavior
Authors: Seitz Shannon J. , Lord Charles G. , Taylor Cheryl A.
Published: June 2007

The research examined an additional proposed moderator of the attitude-behavior relationship: the activity level of emotions associated with an attitude object. In Experiment 1, participants who self-generated active rather than passive emotions as being associated with gay men displayed greater attitude-behavior consistency in hiring recommendations for a gay job applicant, as did participants who rated active rather than passive experimenter-provided emotions as being associated with gay men. In Experiment 2, participants who were instructed to associate active rather than passive emotions with gay men subsequently displayed greater attitude-behavior consistency in similar hiring recommendations. It is suggested that future research on the affective component of attitudes might benefit from going beyond consideration of whether the associated emotions entail displeasure or pleasure.
Terror Mismanagement: Evidence That Mortality Salience Exacerbates Phobic and Compulsive Behaviors
Authors: Strachan Eric , Schimel Jeff , Arndt Jamie , Williams Todd , Solomon Sheldon , Pyszczynski Tom , Greenberg Jeff
Published: June 2007

Terror management theory (TMT) posits that cultural worldviews and self-esteem function to buffer humans from mortality-related anxiety. TMT research has shown that important behaviors are influenced by mortality salience (MS) even when they have no obvious connection to death. However, there has been no attempt to investigate TMT processes in anxious responding. The present research examines that question. In Study 1, compared to a control condition, MS increased anxious responding to spider-related stimuli, but only for participants who met criteria for specific phobia. In Study 2, compared to an aversive control condition, MS increased time spent washing hands, but only for those scoring high on a measure of compulsive hand washing (CHW). In Study 3, compared to a different aversive control condition, MS increased avoidance of a social interaction, but only for those scoring high on a measure of social interaction anxiety. The relevance of TMT in anxious responding is discussed.
Platelet particle formation by anti–GPIIIa49-66 Ab, Ca2+ ionophore A23187, and phorbol myristate acetate is induced by reactive oxygen species and inhibited by dexamethasone blockade of platelet phospholipase A2, 12-lipoxygenase, and NADPH oxidase
Authors: Nardi Michael A. , Gor Yelena , Feinmark Steven J. , Xu Fang , Karpatkin Simon
Published: June 2007

An HIV antibody (Ab) against platelet integrin GPIIIa49-66 induces complement-independent platelet particle formation by the elaboration of reactive oxygen species (ROS) downstream of the activation of the platelet NADPH oxidase by the 12-lipoxygenase (12-LO) product 12(S)-HETE. To determine whether other inducers of platelet particle formation also function via the induction of ROS, we examined the effects of the Ca2+ ionophore A23187 and phorbol myristate acetate (PMA). Both agents induced oxidative platelet particle formation in an identical fashion as Ab, requiring Ca2+ flux and 12(S)-HETE production as well as intact NADPH oxidase and 12-LO pathways. Since HIV-ITP patients with this Ab correct their platelet counts with dexamethasone (Dex), we examined the role of this steroid in this unique autoimmune disorder. Dex at therapeutic concentrations inhibited Ab-, A23187-, or PMA-induced platelet particle formation by inhibiting platelet PLA2, 12-LO, and NADPH oxidase. The operational requirement of translocation of PLA2, 12-LO, and NADPH oxidase components (p67 phox) from cytosol to membrane for induction of ROS was both inhibited and partially reversed by Dex in platelets. We conclude that (1) platelet particle formation can be induced by the generation of ROS; and (2) platelet PLA2, 12-LO, NADPH oxidase, and cytosol membrane translocation, requirements for ROS production, are inhibited by Dex.
BCL6 programs lymphoma cells for survival and differentiation through distinct biochemical mechanisms
Authors: Parekh Samir , Polo Jose M. , Shaknovich Rita , Juszczynski Przemyslaw , Lev Paola , Ranuncolo Stella M. , Yin Yingnan , Klein Ulf , Cattoretti Giorgio , Favera Riccardo Dalla , Shipp Margaret A. , Melnick Ari
Published: June 2007

The BCL6 transcriptional repressor is the most commonly involved oncogene in diffuse large B-cell lymphomas (DLBCLs). Constitutive expression of BCL6 mediates lymphomagenesis through aberrant proliferation, survival, and differentiation blockade. Binding of BCL6 to the SMRT/N-CoR corepressors mediates the BCL6 survival effect in DLBCL. Although the basis for differentiation blockade is unknown in DLBCL, recent data suggest that BCL6 binding to the MTA3 corepressor might be involved. We report that BCL6 and MTA3 are coexpressed in normal germinal center B cells and DLBCL. Depletion of MTA3 in DLBCL cells induced a differentiation-related BCL6 target gene (PRDM1), but not target genes involved in survival. Accordingly, MTA3 and PRDM1 expression are mutually exclusive in germinal center B cells. We performed chromatin immunoprecipitation (ChIP)–on-chip mapping of the PRDM1 locus, identifying a novel BCL6 binding site on intron 3 of the PRDM1 gene, and show that BCL6 recruits MTA3 to this site. In DLBCL cells, MTA3 depletion induced plasmacytic differentiation but did not decrease viability of DLBCL cells. However, MTA3 depletion synergized with a specific BCL6 inhibitor that blocks SMRT/N-CoR binding to decrease DLBCL viability. Taken together, these results show that BCL6 regulates distinct transcriptional programs through the SMRT/N-CoR and MTA3 corepressors, respectively, and provides a basis for combinatorial therapeutic targeting of BCL6.
The role of jak2a in zebrafish hematopoiesis
Authors: Ma Alvin C. H. , Ward Alister C. , Liang Raymond , Leung Anskar Y. H.
Published: June 2007

Janus kinase 2 (Jak2) transduces signals from hematopoietic cytokines, and a gain-of-function mutation (Jak2617V>F) is associated with myeloproliferative diseases, particularly polycythemia vera. In this study, we examined the role of jak2a in zebrafish embryos in knock-down and overexpression studies using morpholinos (MOs) targeting the 5′ untranslated region (UTR) (jak2aUTR-MO) and splice-site junction (jak2aSS-MO) of jak2a, a Jak inhibitor AG490 and a constitutive-active form of jak2a (jak2aca). At 18 and 24 hours after fertilization (hpf), jak2a is expressed predominantly in the intermediate cell mass (ICM; site of primitive hematopoiesis) of wild-type and chordin morphant embryos (characterized by expansion of ICM). Both jak2a MOs and AG490 reduced gata1+ (erythroid) cells in Tg(gata1:GFP) embryos, signal transducer and activation of transcription 5 (stat5) phosphorylation, and gene expression associated with early progenitors (scl and lmo2) and erythroid (gata1, αhe1 and βhe1) and myeloid (spi1 [early] and mpo [late]) lineages. The chordin morphant is associated with increased stat5 phosphorylation, and both jak2a MOs and treatment with AG490 significantly ameliorated ICM expansion and hematopoietic gene up-regulation in these embryos. Injection of plasmid encoding jak2aca significantly increased erythropoiesis and expression of gata1, αhe1 and βhe1, spi1, mpo, and l-plastin. In conclusion, zebrafish jak2a is involved in primitive hematopoiesis under normal and deregulated conditions.
Functional genomics of the pregnant uterus: from expectations to reality, a compilation of studies in the myometrium
Authors: Breuiller-Fouche Michèle , Charpigny Gilles , Germain Guy
Published: June 2007

Background

Studies on the human myometrium have reported on different microarrays containing different sets of genes or ESTs. However each study profiled only a small number of patients due to various constraints. More profiling information would be an addition to our knowledge base of parturition.

Methods

We compiled from five human studies, transcriptional differences between the non pregnant myometrium (NP), preterm myometrium (PTNIL), term myometrium not in labor (TNIL) and term myometrium in labor (TIL). Software modules developed by the Draghici's group at Wayne State University (Detroit, MI, USA) were used to propose a hierarchical list of several KEGG pathways most likely adjusted to changes observed in microarray experiments.

Results

The differential expression of 118 genes could be dispatched in 14 main KEGG pathways that were the most representative of the changes seen in NP and PTNIL, versus TNIL or TIL. Despite the potential of multiple pitfalls inherent to the use of the microarray technology, gene module analysis of the myometrial transcriptome reveals the activation of precise signaling pathways, some of which may have been under evaluated.

Conclusion

The remodelling and maturation processes that the uterus undergoes in pregnancy appear clearly as phenomena which last during the full course of gestation. It is attested by the nature of the main signaling pathways represented, in the comparison of the PTNIL versus TNIL uterus. Comparatively, the onset of labor is a phenomenon which remains less well characterized by these methods of analysis, possibly because it is a phenomenon occurring in too short a window to have been grasped by the studies carried out up to now.
Malarial pigment haemozoin, IFN-gamma, TNF-alpha, IL-1beta and LPS do not stimulate expression of inducible nitric oxide synthase and production of nitric oxide in immuno-purified human monocytes
Authors: Skorokhod Oleksii A , Schwarzer Evelin , Ceretto Monica , Arese Paolo
Published: June 2007

Background

Enhanced production of nitric oxide (NO) following upmodulation of the inducible isoform of NO synthase (iNOS) by haemozoin (HZ), inflammatory cytokines and LPS may provide protection againstPlasmodium falciparummalaria by killing hepatic and blood forms of parasites and inhibiting the cytoadherence of parasitized erythrocytes (RBC) to endothelial cells. Monocytes and macrophages are considered to contribute importantly to protective upregulation of iNOS and production of NO. Data obtained with murine phagocytes fed with human HZ and synthetic HZ (sHZ) indicate that supplemental treatment of those cells with IFN-gamma elicited significant increases in protein and mRNA expression of iNOS and NO production, providing a potential mechanism linking HZ phagocytosis and increased production of NO. Purpose of this study was to analyse the effect ofP. falciparumHZ and sHZ supplemental to treatment with IFN-gamma and/or a stimulatory cytokine-LPS mix on iNOS protein and mRNA expression in immuno-purified human monocytes.

Methods

Adherent immunopurified human monocytes (purity >85%), and murine phagocytic cell lines RAW 264.7, N11 and ANA1 were fed or not withP. falciparumHZ or sHZ and treated or not with IFN-gamma or a stimulatory cytokine-LPS mix. Production of NO was quantified in supernatants, iNOS protein and mRNA expression were measured after immunoprecipitation and Western blotting and quantitative RT-PCT, respectively.

Results

Phagocytosis of HZ/sHZ by human monocytes did not increase iNOS protein and mRNA expression and NO production either after stimulation by IFN-gamma or the cytokine-LPS mix. By contrast, in HZ/sHZ-laden murine macrophages, identical treatment with IFN-gamma and the cytokine-LPS mix elicited significant increases in protein and mRNA expression of iNOS and NOS metabolites production, in agreement with literature data.

Conclusion

Results indicate that human monocytes fed or not with HZ/sHZ were constantly unable to express iNOS and generate NOS metabolites even after stimulation with IFN-gamma or a cytokine-LSP mix that were very active on HZ-fed murine phagocytic lines. Present data do not support the hypothesis that monocytes are mediators of anti-parasitic defence in clinical malaria via activation of iNOS and production of NO, and suggest caution in extrapolating data obtained with murine or hybrid systems to human malaria.
Bilateral male breast cancer with male potential hypogonadism
Authors: Hirose Yukiko , Sasa Mitsunori , Bando Yoshimi , Hirose Toshiyuki , Morimoto Tadaoki , Kurokawa Yasushi , Nagao Taeko , Tangoku Akira
Published: June 2007

Background

Male breast cancer is a comparatively rare disease, and simultaneous bilateral male breast cancer is considered to be an extremely rare event. Risk factors are said to be genetic factors and hormonal abnormalities due to obesity or testicular diseases.

Case presentation

The patient was a 47-year-old Japanese male. His family had no history of female breast cancer. This patient also had hypospadias and hormonal examination indicated the presence of primary testicular potential hypogonadism, and these hormonal abnormalities seemed to be present since childhood or the fetal period. The bilateral breast cancer developed in this man at a comparatively young age, and histopathological studies of multiple sections showed that there was almost no normal epithelial cell in the ducts, while the ducts were almost completely filled with breast cancer cells.

Conclusion

It is thought that male breast cancer is caused by an imbalance between estrogen and testosterone. We cannot rule out the possibility that the breast cancer developed due to the effect of the slight elevation of estrogen over a long period of time, but the actual causative factors in this patient were unable to be definitively identified. In the future, we hope to further elucidate the causes of male breast cancer.
Giant scrotal elephantiasis of inflammatory etiology: a case report
Authors: Denzinger Stefan , Watzlawek Elke , Burger Maximilian , Wieland Wolf F , Otto Wolfgang
Published: June 2007

Background

Scrotal lymphedema is rare outside endemic filariasis regions in Africa and Asia. It is of variable origin in the western world.

Case presentation

We present a case of a 40-year-old European man with massive elephantiasis of the scrotum attributed to chronic inflammation of the lower urinary tract caused by urinary outlet obstruction and diabetes mellitus. The patient underwent subtotal scrotectomy saving penis, testes and spermatic cords and followed by scrotal reconstruction with adequate cosmetic and functional outcome.

Conclusion

In this report we discuss a rare case of scrotal elephantiasis in an European patient, reflect on the etiology and the diagnostic and therapeutic approaches. Surgery can be successful even in giant scrotal elephantiasis.
Computational and transcriptional evidence for microRNAs in the honey bee genome
Authors: Weaver Daniel B , Anzola Juan M , Evans Jay D , Reid Jeffrey G , Reese Justin T , Childs Kevin L , Zdobnov Evgeny M , Samanta Manoj P , Miller Jonathan , Elsik Christine G
Published: June 2007

Background

Non-coding microRNAs (miRNAs) are key regulators of gene expression in eukaryotes. Insect miRNAs help regulate the levels of proteins involved with development, metabolism, and other life history traits. The recently sequenced honey bee genome provides an opportunity to detect novel miRNAs in both this species and others, and to begin to infer the roles of miRNAs in honey bee development.

Results

Three independent computational surveys of the assembled honey bee genome identified a total of 65 non-redundant candidate miRNAs, several of which appear to have previously unrecognized orthologs in the Drosophila genome. A subset of these candidate miRNAs were screened for expression by quantitative RT-PCR and/or genome tiling arrays and most predicted miRNAs were confirmed as being expressed in at least one honey bee tissue. Interestingly, the transcript abundance for several known and novel miRNAs displayed caste or age-related differences in honey bees. Genes in proximity to miRNAs in the bee genome are disproportionately associated with the Gene Ontology terms 'physiological process', 'nucleus' and 'response to stress'.

Conclusion

Computational approaches successfully identified miRNAs in the honey bee and indicated previously unrecognized miRNAs in the well-studied Drosophila melanogaster genome despite the 280 million year distance between these insects. Differentially transcribed miRNAs are likely to be involved in regulating honey bee development, and arguably in the extreme developmental switch between sterile worker bees and highly fertile queens.
Hodgkin’s Reed-Sternberg cell line (KM-H2) promotes a bidirectional differentiation of CD4+CD25+Foxp3+ T cells and CD4+ cytotoxic T lymphocytes from CD4+ naive T cells
Authors: Tanijiri Tsutomu , Shimizu Toshiki , Uehira Kazutaka , Yokoi Takashi , Amuro Hideki , Sugimoto Hiroyuki , Torii Yoshitaro , Tajima Kenichirou , Ito Tomoki , Amakawa Ryuichi , Fukuhara Shirou
Published: June 2007

A recent report revealed that a large population of Hodgkin’s lymphoma-infiltrating lymphocytes (HLILs) consisted of regulatory T cells. In this study, we cocultured CD4+ naive T cells with KM-H2, which was established as a Hodgkin’s Reed-Sternberg cell line, to clarify their ability to induce CD25+Forkhead box P3+ (Foxp3+) T cells. The characteristic analyses of T cells cocultured with KM-H2 revealed the presence of CD4+CD25+ T cells. They expressed CTLA-4, glucocorticoid-induced TNFR family-related gene, and Foxp3 and could produce large amounts of IL-10. Conversely, KM-H2 also generated CD4+ CTLs, which expressed Granzyme B and T cell intracellular antigen-1 in addition to Foxp3+ T cells. They exhibit a strong cytotoxic effect against the parental KM-H2. In conclusion, KM-H2 promotes a bidirectional differentiation of CD4+ naive T cells toward Foxp3+ T cells and CD4+ CTLs. In addition to KM-H2, several cell lines that exhibit the APC function were able to generate Foxp3+ T cells and CD4+ CTLs. Conversely, the APC nonfunctioning cell lines examined did not induce both types of cells. Our findings suggest that the APC function of tumor cells is essential for the differentiation of CD4+ naive T cells into CD25+Foxp3+ T cells and CD4+ CTLs and at least partly explains the predominance of CD25+Foxp3+ T cells in HLILs and their contribution to a better prognosis. Therefore, in APC-functioning tumors, including classical Hodgkin lymphomas, which generate Foxp3+ T cells and CD4+ CTLs, these T cell repertories play a beneficial role synergistically in disease stability.
Midazolam vs. Diphenhydramine for the Treatment of Metoclopramide‐induced Akathisia: A Randomized Controlled Trial
Authors: Parlak Ismet , Erdur Bulent , Parlak Mine , Ergin Ahmet , Ayrik Cuneyt , Tomruk Onder , Turkcuer Ibrahim , Ergin Nesrin
Published: June 2007

ObjectivesTo compare the effects of midazolam, which is a fast and short‐acting benzodiazepine, and diphenhydramine, which is a widely used anticholinergic agent, in clinical practice for the treatment of metoclopramide‐induced akathisia.

MethodsAll adults older than 17 years given metoclopramide for nausea and vomiting or for headache and who had akathisia were eligible for this clinical, randomized, double‐blind trial. Patients were randomized to receive diphenhydramine or midazolam. Subjective, objective, and total akathisia scores and modified Ramsay Sedation Scale scores were recorded. Repeated‐measures analysis of variance was used to compare the efficacy and side effects of the medications.

ResultsForty‐one (73.3%) of the 56 enrolled patients were women. The mean (±SD) age was 39.9 (±15.7) years in the diphenhydramine group and 40.9 (±16.2) years in the midazolam group. Mean subjective, objective, and total akathisia scores in the first 5 minutes declined considerably in the midazolam group compared with the diphenhydramine group (p < 0.001). However, the mean Ramsay Sedation Scale score in the first 15 minutes increased significantly in the midazolam group compared with the diphenhydramine group (p < 0.001).

ConclusionsMidazolam can correct the symptoms of metoclopramide‐induced akathisia faster than diphenhydramine, but it causes more sedation.
Human cell growth requires a functional cytoplasmic exosome, which is involved in various mRNA decay pathways
Authors: van Dijk Erwin L. , Schilders Geurt , Pruijn Ger J.M.
Published: June 2007

The human exosome is a 3′–5′ exoribonuclease complex that functions both in the nucleus and in the cytoplasm to either degrade or process RNA. Little is known yet about potential differences among core exosome complexes in these different cellular compartments and the roles of the individual subunits in maintaining a stable and functional complex. Glycerol gradient sedimentation analyses indicated that a significant subset of nuclear exosomes is present in much larger complexes (60–80S) than the cytoplasmic exosomes (∼10S). Interestingly, siRNA-mediated knock-down experiments indicated that the cytoplasmic exosome is down-regulated much more efficiently than the nuclear exosome. In addition, we observed that knock-down of hRrp41p or hRrp4p but not PM/Scl-100 or PM/Scl-75 leads to codepletion of other subunits. Nevertheless, PM/Scl-100 and PM/Scl-75 are required to maintain normal levels of three different mRNA reporters: a wild-type β-globin mRNA, a β-globin mRNA containing an AU-rich (ARE) instability element, and a β-globin mRNA bearing a premature termination codon (PTC). The increased levels of ARE- and the PTC-containing mRNAs upon down-regulation of the different exosome subunits, in particular PM/Scl-100, appeared to be due to decreased turnover rates. These results indicate that, although not required for exosome stability, PM/Scl-100 and PM/Scl-75 are involved in mRNA degradation, either as essential subunits of a functional exosome complex or as exosome-independent proteins.
Symptoms of Anxiety and Depression in Young Adults: Genetic and Environmental Influences on Stability and Change
Authors: Nes Ragnhild B. , Røysamb Espen , Reichborn-Kjennerud Ted , Harris Jennifer R. , Tambs Kristian
Published: June 2007

Etiological factors for stability and change in symptoms of anxiety and depression, including sex differences, are largely unexplored in young adults. Using biometric modeling and two-wave longitudinal data from 4393 Norwegian twins aged 18 to 31 we explored (i) heritabilities of symptoms of anxiety and depression, (ii) effects of genetic and environmental factors on the stability and change of such symptoms, and (iii) sex-specific effects. The phenotypic cross-time correlations for symptoms of anxiety and depression were estimated to .54 and .49 for males and females, respectively. The best fitting longitudinal model specified additive genetic and individual environmental influences and emerging effects from the shared environment for females only. For both males and females, long-term stability was mainly attributable to stable additive genetic factors, whereas change was essentially related to environmental influences. Minor time-specific genetic effects were indicated, and some stable variance was due to the individual environment. Additive genetic risk factors explained 87% and 68% of the phenotypic cross-time correlation for males and females, with the unique environment accounting for the remaining covariance. The results provide strong evidence for the temporal stability of genetic risk factors for symptoms of anxiety and depression in young adults, and substantial sex-specific influences on heritability, stability and change.