bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of the Poly-3-Hydroxybutyrate (PHB) Granule-Associated Proteins (PhaP1 and PhaP2) on PHB Accumulation and Symbiotic Nitrogen Fixation in
Sinorhizobium meliloti
Rm1021
Authors: Wang Chunxia , Sheng Xiaoyan , Equi Raymie C. , Trainer Maria A. , Charles Trevor C. , Sobral Bruno W. S.
Published: October 2007

Sinorhizobium meliloti
cells store excess carbon as intracellular poly-3-hydroxybutyrate (PHB) granules that assist survival under fluctuating nutritional conditions. PHB granule-associated proteins (phasins) are proposed to regulate PHB synthesis and granule formation. Although the enzymology and genetics of PHB metabolism in
S. meliloti
have been well characterized, phasins have not yet been described for this organism. Comparison of the protein profiles of the wild type and a PHB synthesis mutant revealed two major proteins absent from the mutant. These were identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) as being encoded by the SMc00777 (
phaP1
) and SMc02111 (
phaP2
) genes. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of proteins associated with PHB granules followed by MALDI-TOF confirmed that PhaP1 and PhaP2 were the two major phasins. Double mutants were defective in PHB production, while single mutants still produced PHB, and unlike PHB synthesis mutants that have reduced exopolysaccharide, the double mutants had higher exopolysaccharide levels.
Medicago truncatula
plants inoculated with the double mutant exhibited reduced shoot dry weight (SDW), although there was no corresponding reduction in nitrogen fixation activity. Whether the phasins are involved in a metabolic regulatory response or whether the reduced SDW is due to a reduction in assimilation of fixed nitrogen rather than a reduction in nitrogen fixation activity remains to be established.
Substitution of a Highly Conserved Histidine in the
Escherichia coli
Heat Shock Transcription Factor, σ
32
, Affects Promoter Utilization In Vitro and Leads to Overexpression of the Biofilm-Associated Flu Protein In Vivo
Authors: Kourennaia Olga V. , deHaseth Pieter L.
Published: October 2007

The heat shock sigma factor (σ
32
in
Escherichia coli
) directs the bacterial RNA polymerase to promoters of a specific sequence to form a stable complex, competent to initiate transcription of genes whose products mitigate the effects of exposure of the cell to high temperatures. The histidine at position 107 of σ
32
is at the homologous position of a tryptophan residue at position 433 of the main sigma factor of
E. coli
, σ
70
. This tryptophan is essential for the strand separation step leading to the formation of the initiation-competent RNA polymerase-promoter complex. The heat shock sigma factors of all gammaproteobacteria sequenced have a histidine at this position, while in the alpha- and deltaproteobacteria, it is a tryptophan. In vitro the alanine-for-histidine substitution at position 107 (H107A) destabilizes complexes between the GroE promoter and RNA polymerase containing σ
32
, implying that H107 plays a role in formation or maintenance of the strand-separated complex. In vivo, the H107A substitution in σ
32
impedes recovery from heat shock (exposure to 42°C), and it also leads to overexpression at lower temperatures (30°C) of the Flu protein, which is associated with biofilm formation.
Identification and Characterization of the
dps
Promoter of
Mycobacterium smegmatis
: Promoter Recognition by Stress-Specific Extracytoplasmic Function Sigma Factors σ
H
and σ
F
Authors: Chowdhury Rakhi Pait , Gupta Surbhi , Chatterji Dipankar
Published: October 2007

The survival of a bacterium with a depleted oxygen or nutrient supply is important for its long-term persistence inside the host under stressful conditions. We studied a gene,
dps
, from
Mycobacterium smegmatis
, encoding a protein, Dps (for DNA binding protein from starved cells), which is overexpressed under oxidative and nutritional stresses and provides bimodal protection to the bacterial DNA. Characterization of the
dps
promoter in vivo is therefore important. We cloned a 1-kb putative promoter region of the
dps
gene of
M. smegmatis
in an
Escherichia coli
-
Mycobacterium
shuttle vector, pSD5B, immediately upstream of the
lacZ
gene. Promoter activities were assayed in vivo both in solid medium and in liquid cultures by quantitative β-galactosidase activity measurements. To characterize the minimal promoter region, a 200-bp fragment from the whole 1-kb sequence was further cloned in the same vector, and in a similar way, β-galactosidase activity was quantitated. Primer extension analysis was performed to determine the +1 transcription start site of the gene. Point mutations were inserted in the putative promoter sequences in the −10 and −20 regions, and the promoter sequence was confirmed. The promoter was not recognized by purified
M. smegmatis
core RNA polymerase reconstituted with purified
Mycobacterium tuberculosis
σ
A
or σ
B
during multiple- and single-round in vitro transcription assays. Promoter-specific in vivo pull-down assays with an immobilized 1-kb DNA fragment containing the
dps
promoter established that extracellular function sigma factors were associated with this starvation-inducible promoter. Single-round transcription at the
dps
promoter further supported the idea that only core RNA polymerase reconstituted with σ
F
or σ
H
can generate proper transcripts.
Identification of a Fourth Formate Dehydrogenase in
Methylobacterium extorquens
AM1 and Confirmation of the Essential Role of Formate Oxidation in Methylotrophy
Authors: Chistoserdova Ludmila , Crowther Gregory J. , Vorholt Julia A. , Skovran Elizabeth , Portais Jean-Charles , Lidstrom Mary E.
Published: October 2007

A mutant of
Methylobacterium extorquens
AM1 with lesions in genes for three formate dehydrogenase (FDH) enzymes was previously described by us (L. Chistoserdova, M. Laukel, J.-C. Portais, J. A. Vorholt, and M. E. Lidstrom, J. Bacteriol. 186:22-28, 2004). This mutant had lost its ability to grow on formate but still maintained the ability to grow on methanol. In this work, we further investigated the phenotype of this mutant. Nuclear magnetic resonance experiments with [
13
C]formate, as well as
14
C-labeling experiments, demonstrated production of labeled CO
2
in the mutant, pointing to the presence of an additional enzyme or a pathway for formate oxidation. The tungsten-sensitive phenotype of the mutant suggested the involvement of a molybdenum-dependent enzyme. Whole-genome array experiments were conducted to test for genes overexpressed in the triple-FDH mutant compared to the wild type, and a gene (
fdh4A
) was identified whose translated product carried similarity to an uncharacterized putative molybdopterin-binding oxidoreductase-like protein sharing relatively low similarity with known formate dehydrogenase alpha subunits. Mutation of this gene in the triple-FDH mutant background resulted in a methanol-negative phenotype. When the gene was deleted in the wild-type background, the mutant revealed diminished growth on methanol with accumulation of high levels of formate in the medium, pointing to an important role of FDH4 in methanol metabolism. The identity of FDH4 as a novel FDH was also confirmed by labeling experiments that revealed strongly reduced CO
2
formation in growing cultures. Mutation of a small open reading frame (
fdh4B
) downstream of
fdh4A
resulted in mutant phenotypes similar to the phenotypes of
fdh4A
mutants, suggesting that
fdh4B
is also involved in formate oxidation.
Mapping Critical Interactive Sites within the Periplasmic Domain of the
Vibrio cholerae
Type II Secretion Protein EpsM
Authors: Johnson Tanya L. , Scott Maria E. , Sandkvist Maria
Published: October 2007

The type II secretion (T2S) system is present in many gram-negative species, both pathogenic and nonpathogenic, where it supports the delivery of a variety of toxins, proteases, and lipases into the extracellular environment. In
Vibrio cholerae
, the T2S apparatus is composed of 12 Eps proteins that assemble into a multiprotein complex that spans the entire cell envelope. Two of these proteins, EpsM and EpsL, are key components of the secretion machinery present in the inner membrane. In addition to likely forming homodimers, EpsL and EpsM have been shown to form a stable complex in the inner membrane and to protect each other from proteolytic degradation. To identify and map the specific regions of EpsM involved in protein-protein interactions with both another molecule of EpsM and EpsL, we tested the interactions of deletion constructs of EpsM with full-length EpsM and EpsL by functional characterization and copurification as well as coimmunoprecipitation. Analysis of the truncated EpsM mutants revealed that the region of EpsM from amino acids 100 to 135 is necessary for EpsM to form homo-oligomers, while residues 84 to 99 appear to be critical for a stable interaction with EpsL.
Expression of the σF-DirectedcsfBLocus Prevents Premature Appearance of σGActivity during Sporulation ofBacillus subtilis
Authors: Chary Vasant K. , Xenopoulos Panagiotis , Piggot Patrick J.
Published: October 2007

During sporulation, σGbecomes active in the prespore upon the completion of engulfment. We show that the inactivation of the σF-directedcsfBlocus resulted in premature activation of σG. CsfB exerted control distinct from but overlapping with that exerted by LonA to prevent inappropriate σGactivation. The artificial induction ofcsfBseverely compromised spore formation.
Full Activation of
Enterococcus faecalis
Gelatinase by a C-Terminal Proteolytic Cleavage
Authors: Del Papa Maria Florencia , Hancock Lynn E. , Thomas Vinai C. , Perego Marta
Published: October 2007

Enterococci account for nearly 10% of all nosocomial infections and constitute a significant treatment challenge due to their multidrug resistance properties. One of the well-studied virulence factors of
Enterococcus faecalis
is a secreted bacterial protease, termed gelatinase, which has been shown to contribute to the process of biofilm formation. Gelatinase belongs to the M4 family of bacterial zinc metalloendopeptidases, typified by thermolysin. Gelatinase is synthesized as a preproenzyme consisting of a signal sequence, a putative propeptide, and then the mature enzyme. We determined that the molecular mass of the mature protein isolated from culture supernatant was 33,030 Da, which differed from the predicted molecular mass, 34,570 Da, by over 1,500 Da. Using N-terminal sequencing, we confirmed that the mature protein begins at the previously identified sequence VGSEV, thus suggesting that the 1,500-Da molecular mass difference resulted from a C-terminal processing event. By using mutants with site-directed mutations within a predicted C-terminal processing site and mutants with C-terminal deletions fused to a hexahistidine tag, we determined that the processing site is likely to be between residues D304 and I305 and that it requires the Q306 residue. The results suggest that the
E. faecalis
gelatinase requires C-terminal processing for full activation of protease activity, making it a unique enzyme among the members of the M4 family of proteases of gram-positive bacteria.
Transposon Tn
7
Directs Transposition into the Genome of Filamentous Bacteriophage M13 Using the Element-Encoded TnsE Protein
Authors: Finn Jessica A. , Parks Adam R. , Peters Joseph E.
Published: October 2007

The bacterial transposon Tn
7
has a pathway of transposition that preferentially targets conjugal plasmids. We propose that this same transposition pathway recognizes a structure or complex found during filamentous bacteriophage replication, likely by targeting negative-strand synthesis. The ability to insert into both plasmid and bacteriophage DNAs that are capable of cell-to-cell transfer would help explain the wide distribution of Tn
7
relatives.
Genome-wide linkage scan for submaximal exercise heart rate in the HERITAGE family study
Authors: Spielmann Nadine , Leon Arthur S. , Rao D. C. , Rice Treva , Skinner James S. , Rankinen Tuomo , Bouchard Claude
Published: October 2007

The purpose of this study was to identify regions of the human genome linked to submaximal exercise heart rates in the sedentary state and in response to a standardized 20-wk endurance training program in blacks and whites of the HERITAGE Family Study. A total of 701 polymorphic markers covering the 22 autosomes were used in the genome-wide linkage scan, with 328 sibling pairs from 99 white nuclear families and 102 pairs from 115 black family units. Steady-state heart rates were measured at the relative intensity of 60% maximal oxygen uptake (HR60) and at the absolute intensity of 50 W (HR50). Baseline phenotypes were adjusted for age, sex, and baseline body mass index (BMI) and training responses (posttraining minus baseline, Δ) were adjusted for age, sex, baseline BMI, and baseline value of the phenotype. Two analytic strategies were used, a multipoint variance components and a regression-based multipoint linkage analysis. In whites, promising linkages (LOD > 1.75) were identified on 18q21-q22 for baseline HR50 (LOD = 2.64; P = 0.0002) and ΔHR60 (LOD = 2.10; P = 0.0009) and on chromosome 2q33.3 for ΔHR50 (LOD = 2.13; P = 0.0009). In blacks, evidence of promising linkage for baseline HR50 was detected with several markers within the chromosomal region 10q24-q25.3 (peak LOD = 2.43, P = 0.0004 with D10S597). The most promising regions for fine mapping in the HERITAGE Family Study were found on 2q33 for HR50 training response in whites, on 10q25-26 for baseline HR60 in blacks, and on 18q21–22 for both baseline HR50 and ΔHR60 in whites.
Isometric contraction induces rapid myocyte remodeling in cultured rat right ventricular papillary muscles
Authors: Guterl Kathryn A. , Haggart Charles R. , Janssen Paul M. , Holmes Jeffrey W.
Published: October 2007

The hypothesis that elevated systolic stress induces myocyte thickening has been difficult to test directly. We tested this hypothesis in working rat right ventricular papillary muscles using a recently developed technique for long-term muscle culture. Muscles were cultured for 36 h either isometrically at different levels of systolic stress or at physiological amounts and rates of shortening. Isometric contraction induced rapid increases in myocyte diameter regardless of the level of systolic stress, whereas control myocyte dimensions were maintained if physiological amounts and rates of systolic shortening were imposed. Myocyte thickening was accompanied by a significant decrease in cell length and number of sarcomeres in series along the long axis of the myocyte, suggesting that thickening may have occurred in part by rearrangement of existing sarcomeres. We conclude that the pattern of systolic shortening and/or diastolic lengthening regulates myocyte shape in working rat right ventricular papillary muscles, whereas systolic stress plays little or no role.
Effects of cyclooxygenase inhibition on canine coronary artery blood flow and thrombosis
Authors: Hong Ting-Ting , Huang Jinbao , Barrett Terrance D. , Lucchesi Benedict R.
Published: October 2007

This study was designed to determine the effect of inhibitors of cyclooxygenase (COX)-1, COX-2, and the nonselective COX inhibitor naproxen on coronary vasoactivity and thrombogenicity under baseline and lipopolysaccharide (LPS)-induced inflammatory conditions. We hypothesize that endothelial COX-1 is the primary COX isoform in the canine normal coronary artery, which mediates arachidonic acid (AA)-induced vasodilatation. However, COX-2 can be induced and overexpressed by inflammatory mediators and becomes the major local COX isoform responsible for the production of antithrombotic prostaglandins during systemic inflammation. The interventions included the selective COX-1 inhibitor SC-560 (0.3 mg/kg iv), the selective COX-2 inhibitor nimesulide (5 mg/kg iv), or the nonselective COX inhibitor naproxen (3 mg/kg iv). The selective prostacyclin (IP) receptor antagonist RO-3244794 (RO) was used as an investigational tool to delineate the role of prostacyclin (PGI2) in modulating vascular reactivity. AA-induced vasodilatation of the left circumflex coronary artery was suppressed to a similar extent by each of the COX inhibitors and RO. The data suggest that AA-induced vasodilatation in the normal coronary artery is mediated by a single COX isoform, the constitutive endothelial COX-1, which is reported to be susceptible to COX-2 inhibitors. The effect of the COX inhibitors on thrombus formation was evaluated in a model of carotid artery thrombosis secondary to electrolytic-induced vessel wall injury. Pretreatment with LPS (0.5 mg/kg iv) induced a systemic inflammatory response and prolonged the time-to-occlusive thrombus formation, which was reduced in the LPS-treated animals by the administration of nimesulide. In contrast, neither SC-560 nor naproxen influenced the time to thrombosis in the animals pretreated with LPS. The data are of significance in view of reported adverse cardiovascular events observed in clinical trials involving the use of selective COX-2 inhibitors, thereby suggesting that the endothelial constitutive COX-1 and the inducible vascular COX-2 serve important functions in maintaining vascular homeostasis.
Increased metaboreflex activity is related to exercise intolerance in heart transplant patients
Authors: Houssiere Anne , Gujic Marko , Deboeck Gael , Ciarka Agnieszka , Naeije Robert , van de Borne Philippe
Published: October 2007

Heart transplantation does not normalize exercise capacity or the ventilatory response to exercise. We hypothesized that excessive muscle reflex activity, as assessed by the muscle sympathetic nerve activity (MSNA) response to handgrip exercise, persists after cardiac transplantation and that this mechanism is related to exercise hyperpnea in heart transplant recipients (HTRs). We determined the MSNA, ventilatory, and cardiovascular responses to isometric and dynamic handgrips in 11 HTRs and 10 matched control subjects. Handgrips were followed by a post-handgrip ischemia to isolate the metaboreflex contribution to exercise responses. HTRs and control subjects also underwent recordings during isocapnic hypoxia and a maximal, symptom-limited, cycle ergometer exercise test. HTRs had higher resting MSNA ( P < 0.01) and heart rate ( P < 0.01) than the control subjects. Isometric handgrip increased MSNA in HTRs more than in the controls ( P = 0.003). Dynamic handgrip increased MSNA only in HTRs. During post-handgrip ischemia, MSNA and ventilation remained more elevated in HTRs ( P < 0.05). The MSNA and ventilatory responses to hypoxia were also higher in HTRs (both P < 0.04). In HTRs, metaboreflex overactivity was related to the ventilatory response to exercise, characterized by the regression slope relating ventilation to CO2 output ( r = +0.8; P < 0.05) and a lower peak ventilation ( r = +0.81; P < 0.05) during cycle ergometer exercise tests. However, increased chemoreflex sensitivity ( r = +0.91; P < 0.005), but not metaboreflex activity, accounted for the lower peak ventilation during exercise in a stepwise regression analysis. In conclusion, heart transplantation does not normalize muscle metaboreceptor activity; both increased metaboreflex and chemoreflex control are related to exercise intolerance in HTRs.
Protective roles of adenosine A1, A2A, and A3receptors in skeletal muscle ischemia and reperfusion injury
Authors: Zheng Jingang , Wang Rubio , Zambraski Edward , Wu Dan , Jacobson Kenneth A. , Liang Bruce T.
Published: October 2007

Although adenosine exerts cardio-and vasculoprotective effects, the roles and signaling mechanisms of different adenosine receptors in mediating skeletal muscle protection are not well understood. We used a mouse hindlimb ischemia-reperfusion model to delineate the function of three adenosine receptor subtypes. Adenosine A3receptor-selective agonist 2-chloro- N6-(3-iodobenzyl)adenosine-5′- N-methyluronamide (Cl-IBMECA; 0.07 mg/kg ip) reduced skeletal muscle injury with a significant decrease in both Evans blue dye staining (5.4 ± 2.6%, n = 8 mice vs. vehicle-treated 28 ± 6%, n = 7 mice, P < 0.05) and serum creatine kinase level (1,840 ± 910 U/l, n = 13 vs. vehicle-treated 12,600 ± 3,300 U/l, n = 14, P < 0.05), an effect that was selectively blocked by an A3receptor antagonist 3-ethyl-5-benzyl-2-methyl-6-phenyl-4-phenylethynyl-1,4-(±)-dihydropyridine-3,5-dicarboxylate (MRS-1191; 0.05 mg/kg). The adenosine A1receptor agonist 2-chloro- N6-cyclopentyladenosine (CCPA; 0.05 mg/kg) also exerted a cytoprotective effect, which was selectively blocked by the A1antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX; 0.2 mg/kg). The adenosine A2Areceptor agonist 2- p-(2-carboxyethyl)phenethylamino-5′- N-ethylcarboxamidoadenosine (CGS-21680; 0.07 mg/kg)-induced decrease in skeletal muscle injury was selectively blocked by the A2Aantagonist 2-(2-furanyl)-7-[3-(4-methoxyphenyl)propyl]-7H-pyrazolo[4,3-e] [1,2,4]triazolo[1,5-C]pyrimidin-5-amine (SCH-442416; 0.017 mg/kg). The protection induced by the A3receptor was abrogated in phospholipase C-β2/β3 null mice, but the protection mediated by the A1or A2Areceptor remained unaffected in these animals. The adenosine A3receptor is a novel cytoprotective receptor that signals selectively via phospholipase C-β and represents a new target for ameliorating skeletal muscle injury.
Changes in forearm muscle temperature alter renal vascular responses to isometric handgrip
Authors: Kuipers Nathan T. , Sauder Charity L. , Kearney Matthew L. , Ray Chester A.
Published: October 2007

The purpose of the present study was to examine the effect of heating and cooling the forearm muscles on renal vascular responses to ischemic isometric handgrip (IHG). It was hypothesized that heating and cooling the forearm would augment and attenuate, respectively, renal vascular responses to IHG. Renal vascular responses to IHG were studied during forearm heating at 39°C ( n = 15, 26 ± 1 yr) and cooling at 26°C ( n = 12, 26 ± 1 yr). For a control trial, subjects performed the experimental protocol while the forearm was normothermic (∼34°C). Muscle temperature (measured by intramuscular probe) was controlled by changing the temperature of water cycling through a water-perfused sleeve. The experimental protocol was as follows: 3 min at baseline, 1 min of ischemia, ischemic IHG to fatigue, and 2 min of postexercise muscle ischemia. At rest, renal artery blood velocity (RBV; Doppler ultrasound) and renal vascular conductance (RVC = RBV/mean arterial blood pressure) were not different between normothermia and the two thermal conditions. During ischemic IHG, there were greater decreases in RBV and RVC in the heating trial. However, RBV and RVC were similar during postexercise muscle ischemia during heating and normothermia. RVC decreased less during cooling than in normothermia while the subjects performed the ischemic IHG protocol. During postexercise muscle ischemia, RVC was greater during cooling than in normothermia. These results indicate that heating augments mechanoreceptor-mediated renal vasoconstriction whereas cooling blunts metaboreceptor-mediated renal vasoconstriction.
Exercise-mediated regulation of Hsp70 expression following aerobic exercise training
Authors: Melling C. W. James , Thorp David B. , Milne Kevin J. , Krause Matthew P. , Noble Earl G.
Published: October 2007

An issue central to understanding the biological benefits associated with regular exercise training is to elucidate the intracellular mechanisms governing exercise-conferred cardioprotection. Heat shock proteins (HSPs), most notably the inducible 70-kDa HSP family member Hsp70, are believed to participate in the protection of the myocardium during cardiovascular stress. Following acute exercise, activation of PKA mediates the suppression of an intermediary protein kinase, ERK1/2, which phosphorylates and suppresses the activation of the heat shock transcription factor 1 (HSF1). However, following exercise training, ERK1/2 has been reported to regulate the transcriptional activation of several genes involved in cell growth and proliferation and has been shown to be associated with training-mediated myocardial hypertrophy. The present project examined the transcriptional activation of hsp70 gene expression in acutely exercised (60 min at 30 m/min) naïve sedentary and aerobically trained (8 wk, low intensity) male Sprague-Dawley rats. Following acute exercise stress, no significant differences were demonstrated in the expression of myocardial Hsp70 mRNA and activation of PKA between sedentary and trained animals. However, trained animals elicited expression of the hsp70 gene ( P < 0.05) in the presence of elevated ERK1/2 activation. Given the association of ERK1/2 and the suppression of hsp70 gene expression following acute exercise in naïve sedentary rats, these results suggest that training results in adaptations that allow for the simultaneous initiation of both proliferative and protective responses. While it is unclear what factors are associated with this training-related shift, increases in HSF1 DNA binding affinity ( P < 0.05) and posttranscriptional modifications of the Hsp70 transcript are suggested.
IL-17 stimulates MMP-1 expression in primary human cardiac fibroblasts via p38 MAPK- and ERK1/2-dependent C/EBP-β, NF-κB, and AP-1 activation
Authors: Cortez Dolores M. , Feldman Marc D. , Mummidi Srinivas , Valente Anthony J. , Steffensen Bjorn , Vincenti Matthew , Barnes Jeffrey L. , Chandrasekar Bysani
Published: October 2007

Matrix metalloproteinases (MMPs) degrade collagen and mediate tissue remodeling. The novel cytokine IL-17 is expressed during various inflammatory conditions and modulates MMP expression. We investigated the effect of IL-17 on MMP-1 expression in primary human cardiac fibroblasts (HCF) and delineated the signaling pathways involved. HCF were treated with recombinant human IL-17. MMP-1 expression was analyzed by Northern blotting, RT-quantitative PCR, Western blotting, and ELISA; transcriptional induction and transcription factor binding by EMSA, ELISA, and reporter assay; and p38 MAPK and ERK1/2 activation by protein kinase assays and Western blotting. Signal transduction pathways were investigated using pharmacological inhibitors, small interfering RNA (siRNA), and adenoviral dominant-negative expression vectors. IL-17 stimulated MMP-1 gene transcription, net mRNA levels, protein, and promoter-reporter activity in HCF. This response was blocked by IL-17 receptor-Fc chimera and IL-17 receptor antibodies, but not by IL-6, TNF-α, or IL-1β antibodies. IL-17-stimulated type I collagenase activity was inhibited by the MMP inhibitor GM-6001 and by siRNA-mediated MMP-1 knockdown. IL-17 stimulated activator protein-1 [AP-1 (c-Fos, c-Jun, and Fra-1)], NF-κB (p50 and p65), and CCAAT enhancer-binding protein (C/EBP)-β DNA binding and reporter gene activities, effects attenuated by antisense oligonucleotides, siRNA-mediated knockdown, or expression of dominant-negative signaling proteins. Inhibition of AP-1, NF-κB, or C/EBP activation attenuated IL-17-stimulated MMP-1 expression. IL-17 induced p38 MAPK and ERK1/2 activation, and inhibition by SB-203580 and PD-98059 blunted IL-17-mediated transcription factor activation and MMP-1 expression. Our data indicate that IL-17 induces MMP-1 in human cardiac fibroblasts directly via p38 MAPK- and ERK-dependent AP-1, NF-κB, and C/EBP-β activation and suggest that IL-17 may play a critical role in myocardial remodeling.
Acetaminophen-mediated cardioprotection via inhibition of the mitochondrial permeability transition pore-induced apoptotic pathway
Authors: Hadzimichalis Norell M. , Baliga Sunanda S. , Golfetti Roseli , Jaques Kathryn M. , Firestein Bonnie L. , Merrill Gary F.
Published: October 2007

Our laboratory has previously reported that acetaminophen confers functional cardioprotection following cardiac insult, including ischemia/reperfusion, hypoxia/reoxygenation, and exogenous peroxynitrite administration. In the present study, we further examined the mechanism of acetaminophen-mediated cardioprotection following ischemia/reperfusion injury. Langendorff-perfused guinea pig hearts were exposed to acute treatment with acetaminophen (0.35 mM) or vehicle beginning at 15 min of a 30-min baseline stabilization period. Low-flow global myocardial ischemia was subsequently induced for 30 min followed by 60 min of reperfusion. At the completion of reperfusion, hearts were homogenized and separated into cytosolic and mitochondrial fractions. Mitochondrial swelling and mitochondrial cytochrome c release were assessed and found to be significantly and completely reduced in acetaminophen- vs. vehicle-treated hearts following reperfusion. In a separate group of hearts, ventricular myocytes were isolated and subjected to fluorescence-activated cell sorting. Acetaminophen-treated hearts showed a significant decrease in late stage apoptotic myocytes compared with vehicle-treated hearts following injury (58 ± 1 vs. 81 ± 5%, respectively). These data, together with electron micrograph analysis, suggest that acetaminophen mediates cardioprotection, in part, via inhibition of the mitochondrial permeability transition pore and subsequent apoptotic pathway.
Interactions between oxidative stress and inflammation in salt-sensitive hypertension
Authors: Tian N. , Moore R. S. , Braddy S. , Rose R. A. , Gu J.-W. , Hughson M. D. , Manning R. D.
Published: October 2007

The goal of this study was to test the hypothesis that increases in oxidative stress in Dahl S rats on a high-salt diet help to stimulate renal nuclear factor-κB (NF-κB), renal proinflammatory cytokines, and chemokines, thus contributing to hypertension, renal damage, and dysfunction. We specifically studied whether antioxidant treatment of Dahl S rats on high Na intake would decrease renal inflammation and thus attenuate the hypertensive and adverse renal responses. Sixty-four 7- to 8-wk-old Dahl S or R/Rapp strain rats were maintained for 5 wk on high Na (8%) or high Na + vitamins C (1 g/l in drinking water) and E (5,000 IU/kg in food). Arterial and venous catheters were implanted at day 21. By day 35 in the high-Na S rats, antioxidant treatment significantly increased the renal reduced-to-oxidized glutathione ratio and decreased renal cortical H2O2and O2•−release and renal NF-κB. Antioxidant treatment with vitamins C and E in high-Na S rats also decreased renal monocytes/macrophages in the glomeruli, cortex, and medulla, decreased tumor necrosis factor-α by 39%, and decreased monocyte chemoattractant protein-1 by 38%. Vitamin-treated, high-Na S rats also experienced decreases in arterial pressure, urinary protein excretion, renal tubulointerstitial damage, and glomerular necrosis and increases in glomerular filtration rate and renal plasma flow. In conclusion, antioxidant treatment of high-Na Dahl S rats decreased renal inflammatory cytokines and chemokines, renal immune cells, NF-κB, and arterial pressure and improved renal function and damage.
Nucleoside and nucleobase transporters of primary human cardiac microvascular endothelial cells: characterization of a novel nucleobase transporter
Authors: Bone Derek B. J. , Hammond James R.
Published: October 2007

Levels of cardiovascular active metabolites, like adenosine, are regulated by nucleoside transporters of endothelial cells. We characterized the nucleoside and nucleobase transport capabilities of primary human cardiac microvascular endothelial cells (hMVECs). hMVECs accumulated 2-[3H]chloroadenosine via the nitrobenzylmercaptopurine riboside-sensitive equilibrative nucleoside transporter 1 (ENT1) at a Vmaxof 3.4 ± 1 pmol·μl−1·s−1, with no contribution from the nitrobenzylmercaptopurine riboside-insensitive ENT2. Inhibition of 2-chloroadenosine uptake by ENT1 blockers produced monophasic inhibition curves, which are also compatible with minimal ENT2 expression. The nucleobase [3H]hypoxanthine was accumulated within hMVECs ( Km= 96 ± 37 μM; Vmax= 1.6 ± 0.3 pmol·μl−1·s−1) despite the lack of a known nucleobase transport system. This novel transporter was dipyridamole-insensitive but could be inhibited by adenine ( Ki= 19 ± 7 μM) and other purine nucleobases, including chemotherapeutic analogs. A variety of other cell types also expressed the nucleobase transporter, including the nucleoside transporter-deficient PK( 15 ) cell line (PK15NTD). Further characterization of [3H]hypoxanthine uptake in the PK15NTD cells showed no dependence on Na+or H+. PK15NTD cells expressing human ENT2 accumulated 4.5-fold more [3H]hypoxanthine in the presence of the ENT2 inhibitor dipyridamole than did PK15NTD cells or hMVECs, suggesting trapping of ENT2-permeable metabolites. Understanding the nucleoside and nucleobase transporter profiles in the vasculature will allow for further study into their roles in pathophysiological conditions such as hypoxia or ischemia.
Impaired activation of ATP-sensitive K+channels in endocardial myocytes from left ventricular hypertrophy
Authors: Shimokawa Junichi , Yokoshiki Hisashi , Tsutsui Hiroyuki
Published: October 2007

ATP-sensitive K+(KATP) channels are essential for maintaining the cellular homeostasis against metabolic stress. Myocardial remodeling in various pathologies may alter this adaptive response to such stress. It was reported that transmural electrophysiological heterogeneity exists in ventricular myocardium. Therefore, we hypothesized that the KATPchannel properties might be altered in hypertrophied myocytes from endocardium. To test this hypothesis, we determined the KATPchannel currents using the perforated patch-clamp technique, open cell-attached patches, and excised inside-out patches in both endocardial and epicardial myocytes isolated from hypertrophied [spontaneous hypertensive rats (SHR)] vs. normal [Wistar-Kyoto rats (WKY)] left ventricle. In endocardial cells, KATPchannel currents ( IK,ATP), produced by 2 mM CN−and no glucose at 0 mV, were significantly smaller ( P < 0.01), and time required to reach peak currents after onset of KATPchannel opening (Timeonset to peak) was significantly longer (319 ± 46 vs. 177 ± 37 s, P = 0.01) in the SHR group ( n = 9) than the WKY group ( n = 13). However, in epicardial cells, there were no differences in IK,ATPand Timeonset to peakbetween the groups (SHR, n = 12; WKY, n = 12). The concentration-open probability-response curves obtained during the exposure of open cells and excised patches to exogenous ATP revealed the impaired KATPchannel activation in endocardial myocytes from SHR. In conclusion, KATPchannel activation under metabolic stress was impaired in endocardial cells from rat hypertrophied left ventricle. The deficit of endocardial KATPchannels to decreased intracellular ATP might contribute to the maladaptive response of hypertrophied hearts to ischemia.
Enhanced nitric oxide-mediated chemoreceptor inhibition and altered cyclic GMP signaling in rat carotid body following chronic hypoxia
Authors: He L. , Chen J. , Liu X. , Dinger B. , Fidone S.
Published: October 2007

Multiple studies have shown that chronic hypoxia (CH) elicits a time-dependent upregulation of carotid body chemoreceptor sensitivity in mammals. In the present study, we demonstrate that enhanced excitation is accompanied by a parallel increase of nitric oxide (NO)-dependent inhibition, which acts via a CH-induced modification of the normal mechanism in O2-sensitive type I cells. The NO synthase inhibitor, NG-nitro-l-arginine methyl ester (l-NAME), elicits a progressively larger increase in carotid sinus nerve (CSN) chemoreceptor activity following incremental increases in CH exposure lasting 1–16 days. The inhibitory effect of the NO donor, S-nitroso- N-acetyl-penicillamine (SNAP), on CSN activity is enhanced following CH. However, the activation of soluble guanylate cyclase (sGC) by SNAP, assessed via production of cGMP, is impaired, along with decreased expression of sGC mRNA transcript. Inhibition of hypoxia-evoked Ca2+ responses by SNAP is mediated via a cGMP/protein kinase G (PKG)-dependent mechanism in normal type I cells that is sensitive to the PKG inhibitor KT-5823, but following CH, inhibitory responses are minimally sensitive to PKG inhibition. The data are consistent with the hypothesis that CH hampers cGMP-mediated inhibition of type I cells in favor of an alternative mechanism.
Evidence for Two Types of Bipolar Depression Using a Dimensional Approach
Authors: Henry Chantal , M’Baïlara Katia , Poinsot Rollon , Casteret Anne-Aurelie , Sorbara Frédéric , Leboyer Marion , Vieta Eduard
Published: October 2007

Background: Although there is a great heterogeneity of depressive states in bipolar patients, there is only one definition in international classifications for describing them. However, this variety seems particularly important to recognize because of the possible exacerbation of some of these bipolar depressive states by antidepressants. We aimed at assessing whether it is possible to distinguish different forms of bipolar depression using a dimensional approach. Methods: We characterized 60 bipolar patients with a Major Depressive Episode (DSM-IV) using a new tool (MAThyS; Multidimensional Assessment of Thymic States), assessing five fundamental dimensions (emotional reactivity, cognitive speed, psychomotor function, motivation, and sensory perception) of mood states. Results: A cluster analysis using the items of the dimensional scale revealed two types of depressive state: group 1 (n = 38), which had a low score, is characterized by an inhibition in all dimensions, whereas group 2 (n = 22) is characterized by an overactivation. The emotional reactivity is the most relevant dimension for discriminating these two types of depression (group 1: hyporeactivity; group 2: hyperreactivity), whereas sadness is not. Conclusions: Bipolar depressive states are not homogeneous. A dimensional approach based on emotional reactivity could be useful for discriminating the different forms of bipolar depression. Bipolar depressions may be classified as hyporeactive or hyperreactive. This classification might have therapeutic implications, because hyperreactive depression should belong to the broad spectrum of mixed states.
Short-Term Psychotherapeutic Interventions for Somatizing Patients in the General Hospital: A Randomized Controlled Study
Authors: Schweickhardt Axel , Larisch Astrid , Wirsching Michael , Fritzsche Kurt
Published: October 2007

Background: Treatment acceptance and motivation for psychotherapy of somatizing patients in the general hospital is low. Methods: Patients (n = 91) fulfilling the criteria for somatization were randomized into an intervention group (n = 49) and a control group (n = 42). The patients in the intervention group attended 5 psychotherapeutic sessions based on the modified reattribution model. The patients in the control group received psychoeducational reading material. The primary outcomes were motivation for psychotherapy and contacting a psychotherapist after discharge. The secondary outcomes consisted of changes regarding somatoform symptoms, emotional distress and quality of life. Results: Patients from the intervention group were significantly more motivated for psychotherapy (p = 0.001) than patients from the control group. At the 3-month follow-up, 42% of the patients from the intervention group had contacted a psychotherapist, compared to 20% of the patients from the control group (p = 0.045). At the 6-month follow-up, however, the ratio of patients having contacted a psychotherapist had changed to 44 and 29%, respectively, and was no longer significant. The intensity of somatoform symptoms and the anxiety symptoms decreased and mental functioning improved significantly over time for patients from both groups. Conclusions: Short-term psychotherapeutic interventions for somatizing patients in general hospitals have a moderately better effect on motivation for psychotherapy and contacting a psychotherapist than psychoeducational reading material alone. Future studies should attempt to prove the effectiveness of short-term psychoeducational interventions for somatizing patients in the general hospital.
Plasma Thiobarbituric Acid-Reactive Substance Levels in Subclinical Hypothyroidism
Authors: Kebapcilar Levent , Akinci Baris , Bayraktar Firat , Comlekci Abdurrahman , Solak Ahmet , Demir Tevfik , Yener Serkan , Küme Tuncay , Yesil Sena
Published: October 2007

Objective: The purpose of this study was to determine thiobarbituric acid-reactive substance (TBARS) levels in subclinical hypothyroidism and to examine the effect of levothyroxine replacement on TBARS levels. Subjects and Methods: A cohort of 28 female patients with subclinical hypothyroidism and 24 healthy controls were enrolled in this study. The levels of plasma TBARS, serum lipids, and high-sensitive C-reactive protein (CRP) in patients with subclinical hypothyroidism at baseline and after achieving euthyroid state by levothyroxine were assessed. Results: TBARS levels of the patients were similar to those of the control group in the subclinical hypothyroid state and after restoration of euthyroidism by levothyroxine replacement. TBARS levels decreased after levothyroxine treatment, but did not reach statistical significance. There was no significant correlation between TBARS, lipid and CRP levels. Serum CRP levels were higher in subclinical hypothyroidism (4.28 ± 0.9 mg/l) than in the control group (1.95 ± 0.34 mg/l) and the difference was statistically significant (p = 0.03). After achieving euthyroid state, CRP levels decreased significantly in patients with subclinical hypothyroidism from 4.28 ± 0.9 to 2.32 ± 0.6 mg/l (p = 0.006). Conclusion: Our findings suggest that there is no significant alteration of plasma TBARS levels neither in subclinical hypothyroid state nor after achieving euthyroid state. Serum CRP level is higher in patients with subclinical hypothyroidism than in the control group. Normalization of thyroid state seems to effectively reduce serum CRP levels in subclinical hypothyroidism without any correlation with TBARS activity.
Effects of Programs for Prevention of Early Childhood Caries
Authors: Ammari Jumana B. , Baqain Zaid H. , Ashley Paul F.
Published: October 2007

Objective: To determine the most effective intervention program for prevention of early childhood caries. Materials and Methods: All studies published after 1966 were identified by searching electronic databases (Medline, The Cochrane Library, Embase, Dissertation and Serfile databases) and manual searching. Studies were included if they analyzed the effect of an intervention to prevent caries in 0- to 5-year-old children, recorded caries as dmfs, dmft, dfs or dft, and utilized a randomized controlled study design. Results: The initial search produced 916 citations, 19 of which met the inclusion criteria. The quality of the articles was assessed independently by the reviewers based on randomized selection and double blinding. The 7 articles included in the actual review evaluated the effects of dental health education, prenatal fluoride administration, topical fluoride application, preventive dental programs, and use of fluoridated toothpaste. Meta-analysis was not possible because of differences in the types of intervention among the studies. Conclusion: Conclusive evidence regarding the best intervention to prevent early childhood caries could not be drawn due to the flawed design of somepapers. However, fluoride-based interventions appear to be effective in young children. More studies are required to determine the best method of delivery.
Ochrobactrum anthropi Bacteremia in a Child with Inborn Error of Mitochondrial Fatty Acid Oxidation
Authors: Aly Nasser Yehia A. , Salmeen Hadeel N. , Joshi Rajinder M.
Published: October 2007

Objective: To report an incident of bacteremia caused by Ochrobactrum anthropi.Case Presentation and Intervention: The case of a female child aged 2 years and 10 months with a known history of long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency who developed O. anthropi bacteremia during hospital stay is presented. Patient’s history, clinical findings, laboratory and radiological investigations were thoroughly reviewed. The cultured organism was identified using MicroScan WalkAway 96 SI (Dade Behring) as well as by conventional techniques. Imipenem resistance was confirmed by the conventional Kirby-Bauer disk diffusion technique on Muller-Hinton agar with no zone of inhibition around a 10-µg imipenem disk (Hi Media) using the 0.5 McFarland standard. Conclusion: This report shows O. anthropi as a rare nosocomial pathogen that affected a patient who was immunocompromised. The O. anthropi showed multidrug resistance.
Voice Register in Khmu’: Experiments in Production and Perception
Authors: Abramson Arthur S. , Nye Patrick W. , Luangthongkum Theraphan
Published: October 2007

Some Khmu’ dialects have phonologically distinctive voice registers.Auditory observations have claimed a stable distinction between clear voice andhigh pitch for Register 1 and breathy voice and low pitch for Register 2 in theKhmu’ Rawk dialect of northern Thailand. Word pairs distinguished only by registerwere recorded by 25 native speakers. Acoustic analysis yielded F0 and overallamplitude contours, frequencies of F1 and F2 in quasi-steady states of the vowels,relative intensities of higher harmonics to that of the first harmonic, and voweldurations. When circumstances caused early attention to perception testing, thewords of only 8 speakers had been analyzed for properties other than amplitudeand F0. Since the only significant factor that had emerged by then was F0 contour,the synthetic stimuli were made with just a series of seven contours. The labelingby 32 native speakers yielded two categories, demonstrating the sufficiency of F0as an acoustic cue. The completed acoustic analysis showed a significant effect ofone of the harmonic ratios for the women only, suggesting a conservative bias.The language has been shifting toward tonality and may have reached it.
Effects of Acoustic Variability in the Perceptual Learning of Non-Native-Accented Speech Sounds
Authors: Wade Travis , Jongman Allard , Sereno Joan
Published: October 2007

This study addressed whether acoustic variability and category overlap innon-native speech contribute to difficulty in its recognition, and more generallywhether the benefits of exposure to acoustic variability during categorizationtraining are stable across differences in category confusability. Three experimentsconsidered a set of Spanish-accented English productions. The set was seen topose learning and recognition difficulty (experiment 1) and was more variable andconfusable than a parallel set of native productions (experiment 2). A trainingstudy (experiment 3) probed the relative contributions of category central tendencyand variability to difficulty in vowel identification using derived inventoriesin which these dimensions were manipulated based on the results of experiments1 and 2. Training and test difficulty related straightforwardly to category confusabilitybut not to location in the vowel space. Benefits of high-variability exposurealso varied across vowel categories, and seemed to be diminished for highly confusablevowels. Overall, variability was implicated in perception and learning difficultyin ways that warrant further investigation.
The Past and Future of Neuroprotection in Cerebral Ischaemic Stroke
Authors: Shuaib Ashfaq , Hussain Muhammad S.
Published: October 2007

Following the realization that cerebral tissue may survive for hours after an ischaemic insult, several agents with neuroprotective properties in small-animal models of cerebral ischaemia have been tested in patients with acute ischaemic stroke (AIS). Initial attempts at translating the positive effects of these agents from animal models to patients were unsuccessful, possibly as a result of poorly planned experiments in models of ischaemia, and/or clinical trials of AIS that were not optimized to show a positive effect. Newer neuroprotective agents that are believed to act later in the ischaemic cascade may offer a greater chance of success. However, before these agents can be introduced into clinical practice they must undergo assessment in rodent and large-animal models of AIS and, in particular, the dose-response relationship and the treatment time window should be defined. This should be followed by evaluation in carefully designed clinical trials of adequate power, involving subjects receiving an appropriate dose within an optimum time window following the onset of symptoms. There is hope that such careful strategies may guide continued progress in neuroprotective drug development.