bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of theVIER F-BOX PROTEINEGenes fromArabidopsisReveals Their Importance for Plant Growth and Development
Authors: Schwager Katja M. , Calderon-Villalobos Luz Irina A. , Dohmann Esther M.N. , Willige Björn C. , Knierer Stephan , Nill Carola , Schwechheimer Claus
Published: April 2007

E3 ubiquitin ligases (E3s) target proteins for degradation by the 26S proteasome. In SKP1/CDC53/F-box protein–type E3s, substrate specificity is conferred by the interchangeable F-box protein subunit. The vast majority of the 694 F-box proteins encoded by the Arabidopsis thaliana genome remain to be understood. We characterize the VIER F-BOX PROTEINE (VFB; German for FOUR F-BOX PROTEINS) genes from Arabidopsis that belong to subfamily C of the Arabidopsis F-box protein superfamily. This subfamily also includes the F-box proteins TRANSPORT INHIBITOR RESPONSE1 (TIR1)/AUXIN SIGNALING F-BOX (AFB) proteins and EIN3 BINDING F-BOX proteins, which regulate auxin and ethylene responses, respectively. We show that loss of VFB function causes delayed plant growth and reduced lateral root formation. We find that the expression of a number of auxin-responsive genes and the activity of DR5:β-glucuronidase, a reporter for auxin reponse, are reduced in the vfb mutants. This finding correlates with an increase in the abundance of an AUXIN/INDOLE-3-ACETIC ACID repressor. However, we also find that auxin responses are not affected in the vfb mutants and that a representative VFB family member, VFB2, cannot functionally complement the tir1-1 mutant. We therefore exclude the possibility that VFBs are functional orthologs of TIR1/AFB proteins.
Signalling within the neurovascular unit in the mammalian retina
Authors: Metea Monica R. , Newman Eric A.
Published: April 2007

Neuronal activity in the central nervous system evokes localized changes in blood flow, a response termed neurovascular coupling or functional hyperaemia. Modern functional imaging methods, such as functional magnetic resonance imaging (fMRI), measure signals related to functional hyperaemia in order to determine localization of brain function and to diagnose disease. The cellular mechanisms that underlie functional hyperaemia, however, are not well understood. Glial cells have been hypothesized to be intermediaries between neurons and blood vessels in the control of neurovascular coupling, owing to their ability to release vasoactive factors in response to neuronal activity. Using an in vitro preparation of the isolated, intact rodent retina, we have investigated two likely mechanisms of glial control of the vasculature: glial K+ siphoning and glial induction of vasoactive arachidonic acid metabolites. Potassium siphoning is a process by which a K+ current flowing through glial cells transfers K+ released from active neurons to blood vessels. Since slight increases in extracellular K+ can cause vasodilatation, this mechanism was hypothesized to contribute to neurovascular coupling. Our data, however, suggest that glial K+ siphoning does not contribute significantly to neurovascular coupling in the retina. Instead, we suggest that glial cells mediate neurovascular coupling by inducing the production of two types of arachidonic acid metabolites, epoxyeicosatrienoic acids (EETs) and 20‐hydroxyeicosatetraenoic acid (20‐HETE), which dilate and constrict vessels, respectively. We show that both light flashes and direct glial stimulation produce vasodilatation or vasoconstriction mediated by EETs and 20‐HETE, respectively. Further, we show that the type of vasomotor response observed (dilatation or constriction) depends on retinal levels of nitric oxide. Our data also demonstrate that glial cells are necessary intermediaries for signalling from neurons to blood vessels, since functional hyperaemia does not occur when neuron‐to‐glia communication is interrupted. These results indicate that glial cells play an important role in mediating functional hyperaemia and suggest that the regulation of blood flow may involve both vasodilating and vasoconstricting components.
Functional Analysis ofd-Alanylation of Lipoteichoic Acid in the Probiotic StrainLactobacillus rhamnosusGG
Authors: Vélez Mónica Perea , Verhoeven Tine L. A. , Draing Christian , Von Aulock Sonja , Pfitzenmaier Markus , Geyer Armin , Lambrichts Ivo , Grangette Corinne , Pot Bruno , Vanderleyden Jos , De Keersmaecker Sigrid C. J.
Published: April 2007

Lipoteichoic acid (LTA) is a macroamphiphile molecule which performs several functions in gram-positive bacteria, such as maintenance of cell wall homeostasis.d-Alanylation of LTA requires the proteins encoded by thedltoperon, and this process is directly related to the charge properties of this polymer strongly contributing to its function. The insertional inactivation ofdltDof the probiotic strainLactobacillus rhamnosusGG (ATCC 53103) resulted in the complete absence ofd-alanyl esters in the LTA as confirmed by nuclear magnetic resonance analysis. This was reflected in modifications of the bacterial cell surface properties. ThedltDstrain showed 2.4-fold-increased cell length, a low survival capacity in response to gastric juice challenge, an increased sensitivity to human beta-defensin-2, an increased rate of autolysis, an increased capacity to initiate growth in the presence of an anionic detergent, and a decreased capacity to initiate growth in the presence of cationic peptides compared to wild-type results. However, in vitro experiments revealed no major differences for adhesion to human intestinal epithelial cells, biofilm formation, and immunomodulation. These properties are considered to be important for probiotics. The role of thedltoperon in lactobacilli is discussed in view of these results.
Purification, Characterization, Gene Cloning, and Expression of a Novel Alcohol Dehydrogenase with Anti-Prelog Stereospecificity from
Candida parapsilosis
Authors: Nie Yao , Xu Yan , Mu Xiao Qing , Wang Hai Yan , Yang Ming , Xiao Rong
Published: April 2007

An alcohol dehydrogenase from
Candida parapsilosis
CCTCC M203011 was characterized along with its biochemical activity and structural gene. The amino acid sequence shows similarity to those of the short-chain dehydrogenase/reductases but no overall identity to known proteins. This enzyme with unusual stereospecificity catalyzes an anti-Prelog reduction of 2-hydroxyacetophenone to (
S
)-1-phenyl-1,2-ethanediol.
Signal Mimics Derived from a Metagenomic Analysis of the Gypsy Moth Gut Microbiota
Authors: Guan Changhui , Ju Jianhua , Borlee Bradley R. , Williamson Lynn L. , Shen Ben , Raffa Kenneth F. , Handelsman Jo
Published: April 2007

Bacterial signaling is an important part of community life, but little is known about the signal transduction pathways of the as-yet-uncultured members of microbial communities. To address this gap, we aimed to identify genes directing the synthesis of signals in uncultured bacteria associated with the midguts of gypsy moth larvae. We constructed a metagenomic library consisting of DNA extracted directly from the midgut microbiota and analyzed it using an intracellular screen designated METREX, which detects inducers of quorum sensing. In this screen, the metagenomic DNA and a biosensor reside in the same cell. The biosensor consists of a quorum-sensing promoter, which requires an acylhomoserine lactone or other small molecule ligand for activation, driving the expression of the reporter gene
gfp
. We identified an active metagenomic clone encoding a monooxygenase homologue that mediates a pathway of indole oxidation that leads to the production of a quorum-sensing inducing compound. The signal from this clone induces the activities of LuxR from
Vibrio fischeri
and CviR from
Chromobacterium violaceum
. This study is the first to identify a new structural class of quorum-sensing inducer from uncultured bacteria.
Identification of Anaerobic Selenate-Respiring Bacteria from Aquatic Sediments
Authors: Narasingarao Priya , Häggblom Max M.
Published: April 2007

The diversity population of microorganisms with the capability to use selenate as a terminal electron acceptor, reducing it to selenite and elemental selenium by the process known as dissimilatory selenate reduction, is largely unknown. The overall objective of this study was to gain an in-depth understanding of anaerobic biotransformation of selenium in the environment, particularly anaerobic respiration, and to characterize the microorganisms catalyzing this process. Here, we demonstrate the isolation and characterization of four novel anaerobic dissimilatory selenate-respiring bacteria enriched from a variety of sources, including sediments from three different water bodies in Chennai, India, and a tidal estuary in New Jersey. Strains S5 and S7 from India, strain KM from the Meadowlands, NJ, and strain pn1, categorized as a laboratory contaminant, were all phylogenetically distinct, belonging to various phyla in the bacterial domain. The 16S rRNA gene sequence shows that strain S5 constitutes a new genus belonging toChrysiogenetes, while strain S7 belongs to theDeferribacteres, with greater than 98% 16S rRNA gene similarity toGeovibrio ferrireducens. Strain KM is related toMalonomonas rubra,Pelobacter acidigallici, andDesulfuromusaspp., with 96 to 97% 16S rRNA gene similarity. Strain pn1 is 99% similar toPseudomonas stutzeri. Strains S5, S7, and KM are obligately anaerobic selenate-respiring microorganisms, while strain pn1 is facultatively anaerobic. Besides respiring selenate, all these strains also respire nitrate.
Quorum Sensing Enhances the Stress Response in
Vibrio cholerae
Authors: Joelsson Adam , Kan Biao , Zhu Jun
Published: April 2007

Vibrio cholerae
lives in aquatic environments and causes cholera. Here, we show that quorum sensing enhances
V. cholerae
viability under certain stress conditions by upregulating the expression of RpoS, and this regulation acts through HapR, suggesting that a quorum-sensing-enhanced stress response plays a role in
V. cholerae
environmental survival.
Kinetics and Metabolism of
Bifidobacterium adolescentis
MB 239 Growing on Glucose, Galactose, Lactose, and Galactooligosaccharides
Authors: Amaretti Alberto , Bernardi Tatiana , Tamburini Elena , Zanoni Simona , Lomma Mariella , Matteuzzi Diego , Rossi Maddalena
Published: April 2007

The kinetics and the metabolism of
Bifidobacterium adolescentis
MB 239 growing on galactooligosaccharides (GOS), lactose, galactose, and glucose were investigated. An unstructured unsegregated model for growth in batch cultures was developed, and kinetic parameters were calculated with a recursive algorithm. The growth rate and cellular yield were highest on galactose, followed by lactose and GOS, and were lowest on glucose. Lactate, acetate, and ethanol yields allowed the calculation of carbon fluxes toward fermentation products. Distributions between two- and three-carbon products were similar on all the carbohydrates (55 and 45%, respectively), but ethanol yields were different on glucose, GOS, lactose, and galactose, in decreasing order of production. Based on the stoichiometry of the fructose-6-phosphate shunt and on the carbon distribution among the products, the ATP yield was calculated. The highest yield was obtained on galactose, while the yields were 5, 8, and 25% lower on lactose, GOS, and glucose, respectively. Therefore, a correspondence among ethanol production, low ATP yields, and low biomass production was established, demonstrating that carbohydrate preferences may result from different distributions of carbon fluxes through the fermentative pathway. During the fermentation of a GOS mixture, substrate selectivity based on the degree of polymerization was exhibited, since lactose and the trisaccharide were the first to be consumed, while a delay was observed until longer oligosaccharides were utilized. Throughout the growth on both lactose and GOS, galactose accumulated in the cultural broth, suggesting that β(1-4) galactosides can be hydrolyzed before they are taken up.
Role of Chromosomal and Plasmid-Borne Receptor Homologues in the Response of
Bacillus megaterium
QM B1551 Spores to Germinants
Authors: Christie Graham , Lowe Christopher R.
Published: April 2007

Spores of
Bacillus megaterium
QM B1551 germinate in response to a number of trigger compounds, including glucose, proline, leucine, and inorganic salts. An approximate 6-kb region of the 165-kb plasmid was found to harbor a tricistronic receptor operon,
gerU
, and a monocistronic receptor component,
gerVB
. The
gerU
operon was observed to complement the germination response in plasmidless strain PV361 to glucose and leucine, with KBr acting as a cogerminant. Proline recognition is conferred by the monocistronic
gerVB
gene, the presence of which also improves the germination response to other single-trigger compounds. A chimeric receptor, GerU*, demonstrates interchangeability between receptor components and provides evidence that it is the B protein of the receptor that determines germinant specificity. Introduction of the
gerU
/
gerVB
gene cluster to
B. megaterium
KM extends the range of germinants recognized by this strain to include glucose, proline, and KBr in addition to alanine and leucine. A chromosomally encoded receptor, GerA, the B component of which is predicted to be truncated, was found to be functionally redundant. Similarly, the plasmid-borne antiporter gene,
grmA
, identified previously as being essential for germination in QM B1551, did not complement the germination defect in the plasmidless variant PV361. Wild-type spores carrying an insertion-deletion mutation in this cistron germinated normally; thus, the role of GrmA in spore germination needs to be reevaluated in this species.
The Complex of
Sphingomonas elodea
ATCC 31461 Glucose-1-Phosphate Uridylyltransferase with Glucose-1-Phosphate Reveals a Novel Quaternary Structure, Unique among Nucleoside Diphosphate-Sugar Pyrophosphorylase Members
Authors: Aragão David , Fialho Arsénio M. , Marques Ana R. , Mitchell Edward P. , Sá-Correia Isabel , Frazão Carlos
Published: April 2007

Gellan gum is a widely used commercial material, available in many different forms. Its economic importance has led to studies into the biosynthesis of exopolysaccharide gellan gum, which is industrially prepared in high yields using
Sphingomonas elodea
ATCC 31461. Glucose-1-phosphate uridylyltransferase mediates the reversible conversion of glucose-1-phosphate and UTP into UDP-glucose and pyrophosphate, which is a key step in the biosynthetic pathway of gellan gums. Here we present the X-ray crystal structure of the glucose-1-phosphate uridylyltransferase from
S. elodea
. The
S. elodea
enzyme shares strong monomeric similarity with glucose-1-phosphate thymidylyltransferase, several structures of which are known, although the quaternary structures of the active enzymes are rather different. A detailed comparison between
S. elodea
glucose-1-phosphate uridylyltransferase and available thymidylyltransferases is described and shows remarkable structural similarities, despite the low sequence identities between the two divergent groups of proteins.
Dynamic changes in conduction velocity and gap junction properties during development of pacing-induced heart failure
Authors: Akar Fadi G. , Nass Robert D. , Hahn Samuel , Cingolani Eugenio , Shah Manish , Hesketh Geoffrey G. , DiSilvestre Deborah , Tunin Richard S. , Kass David A. , Tomaselli Gordon F.
Published: April 2007

End-stage heart failure (HF) is characterized by changes in conduction velocity (CV) that predispose to arrhythmias. Here, we investigate the time course of conduction changes with respect to alterations in connexin 43 (Cx43) properties and mechanical function during the development of HF. We perform high-resolution optical mapping in arterially perfused myocardial preparations from dogs subjected to 0, 3, 7, 14, and 21 days of rapid pacing to produce variable degrees of remodeling. CV is compared with an index of mechanical function [left ventricular end-diastolic pressure (LVEDP)] and with dynamic changes in the expression, distribution, and phosphorylation of Cx43. In contrast to repolarization, CV was preserved during early stages of remodeling (3 and 7 days) and significantly reduced at later stages, which were associated with marked increases in LVEDP. Measurements of differentially phosphorylated Cx43 isoforms revealed early, sustained downregulation of pan-Cx43 that preceded changes in CV and LVEDP, a gradual rise in a dephosphorylated Cx43 isoform to over twofold baseline levels in end-stage HF, and a late abrupt increase in pan-Cx43, but not dephosphorylated Cx43, lateralization. These data demonstrate that 1) CV slowing occurs only at advanced stages of remodeling, 2) total reduction of pan-Cx43 is an early event that precedes mechanical dysfunction and CV slowing, 3) changes in Cx43 phosphorylation are more closely associated with the onset of HF, and 4) Cx43 lateralization is a late event that coincides with marked CV reduction. These data reveal a novel paradigm of remodeling based on the timing of conduction abnormalities relative to changes in Cx43 isoforms and mechanical dysfunction.
Ten-hour preservation of guinea pig isolated hearts perfused at low flow with air-saturated Lifor solution at 26°C: comparison to ViaSpan solution
Authors: Stowe David F. , Camara Amadou K. S. , Heisner James S. , Aldakkak Mohammed , Harder David R.
Published: April 2007

There is no suitable solution to preserve hearts for longer than 5 h between donor explant and recipient implant. Lifor is a fully artificial preservation medium containing both a nonprotein oxygen and nutrient carrier (nanoparticles) and cellular nutrients, including amino acids and sugars. We proposed that recirculated Lifor solution would satisfactorily preserve guinea pig isolated hearts perfused at low flow with no added O2at room temperature for 10 h. Hearts were isolated from 21 guinea pigs and perfused with Krebs-Ringer (KR) solution (97% O2and 3% CO2) at 37°C. Heart rate, inflow and outflow O2tension, coronary flow, left ventricular pressure (LVP), and maximal and minimal rate of change in LVP (dLVP/d t) were measured. After baseline measurements, hearts were perfused with recirculated Lifor or ViaSpan equilibrated with room air at 15% of control flow at 26°C for 10 h. Hearts were then perfused at 100% flow with KR for 2 h at 37°C. A time control (untreated) group was perfused only with KR solution for 15 h. Lifor arrested and protected hearts against diastolic contracture and maintained a low O2extraction. Compared with time controls, Lifor led to a higher developed LVP and coronary flow; %O2extraction and cardiac efficiency were similar between these two groups. Hearts similarly treated with ViaSpan exhibited diastolic contracture and lower %O2extraction during treatment and, upon reperfusion with KR, exhibited continued diastolic contracture, no return of heart rate or contractility, low coronary flow, low %O2extraction, and marked infarction. For long-term cardiac protection, a suitable preservation solution recirculated at low flow and room temperature without supplemental O2would reduce the support apparatus required for transport. Lifor was far superior to ViaSpan in meeting these requirements.
Antiviral and myocyte protective effects of murine interferon-β and -α2in coxsackievirus B3-induced myocarditis and epicarditis in Balb/c mice
Authors: Wang Yi-Xin , da Cunha Valdeci , Vincelette Jon , White Kathy , Velichko Sharlene , Xu Yifan , Gross Cynthia , Fitch Richard M. , Halks-Miller Meredith , Larsen Brent R. , Yajima Toshitaka , Knowlton Kirk U. , Vergona Ronald , Sullivan Mark E. , Croze Ed
Published: April 2007

The present study tested the hypothesis that murine (m)IFN-β or mIFN-α2can eliminate cardiac viral load and protect cardiomyocytes from injury in animals infected with coxsackievirus B3 (CVB3). CVB3-inoculated male Balb/c mice exhibited signs of illness, including lethargy, progressive weight loss, and death (10% on day 3 and 100% on day 8). Cardiac viral load was high [4,277 ± 1,009 plaque-forming units and 25 ± 5 copies CVB3/hypoxanthine guanine phosphoribosyl transferase 1 mRNA] on day 4. The cardiac tissue exhibited severe inflammatory infiltration and myocyte damage with an average myocarditis integrated pathology score of 2.1 ± 0.2 on day 7. Most of the mice infected with CVB3 also developed epicarditis, and 55% had intraventricular thrombi present. Treatment with mIFN-β [2.5 to 10 million international units (MIU)/kg] dose-dependently improved the general health status in CVB3-inoculated mice, as evidenced by reduction in weight loss, prevention of death, elimination of cardiac viral load, protection of myocytes from injury, decrease in inflammatory cell infiltration, and attenuation of intraventricular thrombus formation. Treatment with 10 MIU/kg mIFN-α2resulted in a similar level of efficacy as that induced by 5 MIU/kg mIFN-β, with the exception that mIFN-α2did not reduce cardiac CVB3 mRNA. However, mIFN-α2, but not any dose group of mIFN-β, significantly attenuated CVB3-induced epicarditis. These data demonstrate antiviral effects for both mIFN-β and mIFN-α2, which lead to protection of the mice from CVB3-induced myocarditis. However, the potential mechanisms leading to a differential host response for the two isoforms of mIFN remain to be elucidated.
Blunted muscle vasodilatation during chemoreceptor stimulation in patients with heart failure
Authors: Di Vanna Andrea , Braga Ana Maria F. W. , Laterza Mateus C. , Ueno Linda M. , Rondon Maria Urbana P. B. , Barretto Antonio C. P. , Middlekauff Holly R. , Negrão Carlos E.
Published: April 2007

Chemoreflex control of sympathetic nerve activity is exaggerated in heart failure (HF) patients. However, the vascular implications of the augmented sympathetic activity during chemoreceptor activation in patients with HF are unknown. We tested the hypothesis that the muscle blood flow responses during peripheral and central chemoreflex stimulation would be blunted in patients with HF. Sixteen patients with HF (49 ± 3 years old, Functional Class II-III, New York Heart Association) and 11 age-paired normal controls were studied. The peripheral chemoreflex control was evaluated by inhalation of 10% O2 and 90% N2 for 3 min. The central chemoreflex control was evaluated by inhalation of 7% CO2 and 93% O2 for 3 min. Muscle sympathetic nerve activity (MSNA) was directly evaluated by microneurography. Forearm blood flow was evaluated by venous occlusion plethysmography. Baseline MSNA were significantly greater in HF patients (33 ± 3 vs. 20 ± 2 bursts/min, P = 0.001). Forearm vascular conductance (FVC) was not different between the groups. During hypoxia, the increase in MSNA was significantly greater in HF patients than in normal controls (9.0 ± 1.6 vs. 0.8 ± 2.0 bursts/min, P = 0.001). The increase in FVC was significantly lower in HF patients (0.00 ± 0.10 vs. 0.76 ± 0.25 units, P = 0.001). During hypercapnia, MSNA responses were significantly greater in HF patients than in normal controls (13.9 ± 3.2 vs. 2.1 ± 1.9 bursts/min, P = 0.001). FVC responses were significantly lower in HF patients (−0.29 ± 0.10 vs. 0.37 ± 0.18 units, P = 0.001). In conclusion, muscle vasodilatation during peripheral and central chemoreceptor stimulation is blunted in HF patients. This vascular response seems to be explained, at least in part, by the exaggerated MSNA responses during hypoxia and hypercapnia.
Effects of sterile pericarditis on connexins 40 and 43 in the atria: correlation with abnormal conduction and atrial arrhythmias
Authors: Ryu Kyungmoo , Li Li , Khrestian Celeen M. , Matsumoto Naomichi , Sahadevan Jayakumar , Ruehr Mary L. , Van Wagoner David R. , Efimov Igor R. , Waldo Albert L.
Published: April 2007

The canine sterile pericarditis model is characterized by impaired conduction and atrial arrhythmia vulnerability. Electrical and structural remodeling processes caused by the inflammatory response likely promote these abnormalities. In the present study, we tested the hypothesis that altered distribution of atrial connexins is associated with markedly abnormal atrial conduction, thereby contributing to vulnerability to atrial flutter (AFL) and atrial fibrillation (AF) induction and maintenance. During rapid pacing and induced, sustained AFL or AF in five sterile pericarditis (SP) and five normal (NL) dogs, epicardial atrial electrograms were recorded simultaneously from both atria (380 electrodes) or from the right atrium (RA) and Bachmann's bundle (212 electrodes). Tissues from RA sites were subjected to immunostaining and immunoblotting to assess connexin (Cx) 40 and Cx43 distribution and expression. Transmural myocyte (α-actinin) and fibroblast (vimentin) volume were also assessed by immunostaining. RA pacing maps showed markedly abnormal conduction in SP, with uniform conduction in NL. Total RA activation time was significantly prolonged in SP vs. NL at 300-ms and 200-ms pacing-cycle lengths. Sustained arrhythmias were only inducible in SP [total: 4/5 (AFL: 3/5; AF: 1/5)]. In NL, Cx40, Cx43, α-actinin, and vimentin were homogeneously distributed transmurally. In SP, Cx40, Cx43, and α-actinin were absent epicardially, decreased midmyocardially, and normal endocardially. SP increased epicardial vimentin expression, suggesting fibroblast proliferation. Immunoblot analysis confirmed reduced expression of Cx40 and Cx43 in SP. The transmural gradient in the volume fraction of Cx40 and Cx43 in SP is associated with markedly abnormal atrial conduction and is likely an important factor in the vulnerability to induction and maintenance of AFL/AF in SP.
Medroxyprogesterone acetate prevents the cardioprotective and anti-inflammatory effects of 17β-estradiol in an in vivo model of myocardial ischemia and reperfusion
Authors: Booth Erin A. , Lucchesi Benedict R.
Published: April 2007

Previous studies demonstrated the protective effects of estrogen administration in models of cardiovascular disease. However, there is a discrepancy between these data and those from the recent clinical trials with hormone replacement therapy in menopausal women. One possible explanation for the divergent results is the addition of progestin to the hormone regimen in the Women's Health Initiative and the Heart and Estrogen/Progestin Replacement Study trials. The aim of the present study was to examine the effects of a combination of 17β-estradiol (E2, 20 μg) and medroxyprogesterone acetate (MPA, 80 μg) on infarct size in New Zealand White rabbits. Infarct size as a percentage of the area at risk was significantly reduced by administration of E230 min before induction of myocardial ischemia compared with vehicle (19.5 ± 3.1 vs. 55.7 ± 2.6%, P < 0.001). However, E2+ MPA failed to elicit a reduction in infarct size (52.5 ± 4.6%), and MPA had no effect (50.8 ± 2.6%). E2also reduced serum levels of cardiac troponin I, immune complex deposition in myocardial tissue, activation of the complement system, and lipid peroxidation. All these effects were reversed by MPA. The results suggest that MPA antagonizes the infarct-sparing effects of E2, possibly through modulation of the immune response after ischemia and reperfusion.
Immunotargeting of catalase to lung endothelium via anti-angiotensin-converting enzyme antibodies attenuates ischemia-reperfusion injury of the lung in vivo
Authors: Nowak Kai , Weih Sandra , Metzger Roman , Albrecht Ronald F. , Post Stefan , Hohenberger Peter , Gebhard Martha-Maria , Danilov Sergei M.
Published: April 2007

Limitation of reactive oxygen species-mediated ischemia-reperfusion (I/R) injury of the lung by vascular immunotargeting of antioxidative enzymes has the potential to become a promising modality for extension of the viability of banked transplantation tissue. The preferential expression of angiotensin-converting enzyme (ACE) in pulmonary capillaries makes it an ideal target for therapy directed toward the pulmonary endothelium. Conjugates of ACE monoclonal antibody (MAb) 9B9 with catalase (9B9-CAT) have been evaluated in vivo for limitation of lung I/R injury in rats. Ischemia of the right lung was induced for 60 min followed by 120 min of reperfusion. Sham-operated animals (sham, n = 6) were compared with ischemia-reperfused untreated animals (I/R, n = 6), I/R animals treated with biotinylated catalase (CAT, n = 6), and I/R rats treated with the conjugates (9B9-CAT, n = 6). The 9B9-CAT accumulation in the pulmonary endothelium of injured lungs was elucidated immunohistochemically. Arterial oxygenation during reperfusion was significantly higher in 9B9-CAT (221 ± 36 mmHg) and sham (215 ± 16 mmHg; P < 0.001 for both) compared with I/R (110 ± 10 mmHg) and CAT (114 ± 30 mmHg). Wet-dry weight ratio of I/R (6.78 ± 0.94%) and CAT (6.54 ± 0.87%) was significantly higher than of sham (4.85 ± 0.29%; P < 0.05), which did not differ from 9B9-CAT (5.58 ± 0.80%). The significantly lower degree of lung injury in 9B9-CAT-treated animals compared with I/R rats was also shown by decreased serum levels of endothelin-1 (sham, 18 ± 9 fmol/mg; I/R, 42 ± 12 fmol/mg; CAT, 36 ± 11 fmol/mg; 9B9-CAT, 26 ± 9 fmol/mg; P < 0.01) and mRNA for inducible nitric oxide synthase (iNOS) [iNOS-GAPDH ratio: sham, 0.15 ± 0.06 arbitrary units (a.u.); I/R, 0.33 ± 0.08 a.u.; CAT, 0.26 ± 0.05 a.u.; 9B9-CAT, 0.14 ± 0.04 a.u.; P < 0.001]. These results validate immunotargeting by anti-ACE conjugates as a prospective and specific strategy to augment antioxidative defenses of the pulmonary endothelium in vivo.
Differential roles of p55 and p75 tumor necrosis factor receptors on stretch-induced pulmonary edema in mice
Authors: Wilson Michael R. , Goddard Michael E. , O'Dea Kieran P. , Choudhury Sharmila , Takata Masao
Published: April 2007

Ventilator-induced lung injury plays a crucial role in the outcome of patients with acute lung injury. Previous studies have shown a role for the cytokine tumor necrosis factor-α (TNF) in stretch-induced alveolar neutrophil recruitment, but the involvement of TNF in stretch-induced pulmonary edema is unclear. We investigated the effects of TNF through its individual p55 and p75 receptors on early pulmonary edema formation during high stretch ventilation, before neutrophil infiltration. Anesthetized wild-type or TNF receptor single/double knockout mice were ventilated with high tidal volume (∼38 ml/kg) for 2 h or until they developed arterial hypotension. Pulmonary edema was assessed by physiological parameters including respiratory mechanics and blood gases, and by lavage fluid protein, lung wet:dry weight ratio, and lung permeability measurements using fluorescence-labeled albumin. High stretch ventilation in wild-type and TNF receptor double knockout animals induced similar pulmonary edema, and only 25–30% of mice completed the protocol. In contrast, the p55 receptor knockout mice were strongly protected from edema formation, with all animals completing the protocol. Myeloperoxidase assay indicated that this protective effect was not associated with decreased pulmonary neutrophil sequestration. The p75 receptor knockout mice, however, displayed increased susceptibility to edema formation, and no animals survived the full 2 h. These results demonstrate a novel role for TNF signaling (independent from its effects on neutrophil recruitment) specifically through the p55 receptor, in promoting high stretch-induced pulmonary edema, whereas p75 signaling may play an opposing role.
A paradoxical temporal response of the PTHrP/PPARγ signaling pathway to lipopolysaccharide in an in vitro model of the developing rat lung
Authors: Rehan Virender K. , Dargan-Batra Soina K. , Wang Ying , Cerny Laura , Sakurai Reiko , Santos Jamie , Beloosesky Ron , Gayle Dave , Torday John S.
Published: April 2007

Chorioamnionitis alters lung development, resulting in a paradoxical decrease in the incidence of respiratory distress syndrome but an increase in the incidence of bronchopulmonary dysplasia (BPD). The mechanism(s) underlying this disparity in the pulmonary outcomes is not known. We hypothesized that specific alterations in alveolar epithelial-mesenchymal interactions might explain this apparent disparity in the pulmonary outcome following chorioamnionitis. We determined the effects of lipopolysaccharide (LPS) on parathyroid hormone-related protein (PTHrP)-driven epithelial-mesenchymal interactions that are essential for normal lung development and homeostasis. Lung explants from embryonic day 19.5 Sprague-Dawley rat fetuses were treated with LPS with or without a PTHrP pathway agonist, prostaglandin J2(PGJ2). LPS treatment affected the production of proinflammatory cytokines and the expression of the key markers of the epithelial-mesenchymal paracrine interactions in a time-dependent manner. At 6 h, there was a significant increase in the expression of PTHrP and the other key markers of alveolar homeostasis without any significant effect on α-smooth muscle actin (αSMA). In contrast, at 72 h, there was a significant decrease in the expression of PTHrP and the other key markers of alveolar homeostasis accompanied by a significant increase in αSMA expression. The cytokine and molecular changes at 72 h were completely prevented by the concomitant treatment with PGJ2. We speculate that these data provide a likely mechanism for the acute stimulation of lung differentiation, accompanied paradoxically by BPD following chorioamnionitis, and suggest that by specifically targeting PTHrP signaling, the inflammation-induced molecular injury that is known to result in BPD can be prevented.
Respiratory syncytial virus induces insensitivity to β-adrenergic agonists in mouse lung epithelium in vivo
Authors: Davis Ian C. , Xu Anna , Gao Zhiqian , Hickman-Davis Judy M. , Factor Phillip , Sullender Wayne M. , Matalon Sadis
Published: April 2007

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in infants and children worldwide. We wished to determine whether intratracheal administration of β-agonists improved alveolar fluid clearance (AFC) across the distal respiratory epithelium of RSV-infected mice. Following intranasal infection with RSV strain A2, AFC was measured in anesthetized, ventilated BALB/c mice by instillation of 5% BSA into the dependent lung. We found that direct activation of protein kinase A by forskolin or 8-bromo-cAMP increased AFC at day 2 after infection with RSV. In contrast, short- and long-acting β-agonists had no effect at either day 2 or day 4. Insensitivity to β-agonists was not a result of elevated plasma catecholamines or lung epithelial cell β-adrenergic receptor degradation. Instead, RSV-infected mice had significantly higher levels of phosphorylated PKCζ in the membrane fractions of their lung epithelial cells. In addition, insensitivity to β-agonists was mediated in a paracrine fashion by KC (the murine homolog of CXCL8) and reversed by inhibition of either PKCζ or G protein-coupled receptor kinase 2 (GRK2). These results indicate that insufficient response to β-agonists in RSV may be caused, at least in part, by impaired β-adrenergic receptor signaling, as a consequence of GRK2-mediated uncoupling of β-adrenergic receptors from adenylyl cyclase.
A Biomechanical Comparison of Initial Fixation Strength of 3 Different Methods of Anterior Cruciate Ligament Soft Tissue Graft Tibial Fixation
Authors: Bartz Reed L. , Mossoni Kory , Tyber Jeffrey , Tokish John , Gall Kenneth , Siparsky Patrick N.
Published: April 2007

Background

Tibial fixation of soft tissue grafts continues to be problematic in the early postoperative period after anterior cruciate ligament reconstruction.

Hypothesis

No differences exist for resistance to slippage of soft tissue grafts fixed with CentraLoc, Intrafix, or 35-mm bioabsorbable interference screws.

Study Design

Controlled laboratory study.

Methods

Bovine tibia and hoof extensor tendons were divided into 3 matched groups with 12 tibia and 12 extensor tendons in each group. Within each group, 6 specimens underwent monotonic loading to failure (1 mm/s), and 6 underwent cyclic loading (10 000 cycles, 125-325 N, 1 Hz).

Results

No statistically significant differences were noted in mean load to failure or stiffness. The mean load to failure (and stiffness) for the 3 types of fixation were as follows: bioabsorbable interference screw, 631.6 ± 130.1 N (88.17 ± 6.79 N/mm); Intrafix, 644.3 ± 195.2 N (81.65 ± 16.5 N/mm); and CentraLoc, 791.1 ± 72.7 N (77.89 ± 7.07 N/mm). The slippage rates under cyclic loading for the 3 types of fixation were bioabsorbable interference screw, 0.336 ± 0.074 µm/cycle; Intrafix, 27.2 ± 31.6 µm/cycle; and CentraLoc, 0.0355 ± 0.0046 µm/cycle. In this model, CentraLoc proved statistically superior in resistance to cyclic loading compared with the bioabsorbable interference screw (P < .05) and Intrafix (P < .0001). The bioabsorbable interference screw proved statistically superior to Intrafix in resistance to cyclic loading (P < .05).

Conclusions

In this bovine model, CentraLoc and bioabsorbable interference screws provided superior resistance to cyclic loading compared with Intrafix.

Clinical Relevance

CentraLoc and bioabsorbable interference screws showed superior resistance to cyclic loading, which may indicate an increased resistance to clinical failure.
Beauty Salons
Authors: Linnan Laura A. , Ferguson Yvonne Owens
Published: April 2007

African American women suffer disproportionately from a wide range of health disparities. This article clarifies how beauty salons can be mobilized at all levels of the social-ecological framework to address disparities in health among African American women. The North Carolina BEAUTY and Health Project is a randomized, controlled intervention trial that takes into account the unique and multilevel features of the beauty salon setting with interventions that address owners, customers, stylists; interactions between customers and stylists; and the salon environment. The authors make explicit the role of the political economy of health theoretical perspective for understanding important factors (social, political, historical, and economic) that should be considered if the goal is to create successful, beauty-salon-based interventions. Despite some important challenges, the authors contend that beauty salons represent a promising setting for maximizing reach, reinforcement, and the impact of public health interventions aimed at addressing health disparities among African American women.
X-linked clonality testing: interpretation and limitations
Authors: Chen George L. , Prchal Josef T.
Published: April 2007

Clonality often defines the diseased state in hematology. Clonal cells are genetically homogenous and derived from the same precursor; their detection is based on genotype or phenotype. Genotypic clonality relies on somatic mutations to mark the clonal population. Phenotypic clonality identifies the clonal population by the expression pattern of surrogate genes that track the clonal process. The most commonly used phenotypic clonality methods are based on the X-chromosome inactivation principle. Clonality detection based on X-chromosome inactivation patterns (XCIP) requires discrimination of the active from the inactive X chromosome and differentiation of each X chromosome's parental origin. Detection methods are based on detection of X-chromosome sequence polymorphisms identified by protein isoforms, transcribed mRNA, and methylation status. Errors in interpreting clonality tests arise from stochastic, genetic, and cell selection pressures on the mechanism of X inactivation. Progressive X-chromosome skewing has recently been suggested by XCIP clonality studies in aging hematopoietic cells. This has led to new insights into the pathophysiology of X-linked and autoimmune disorders. Other research applications include combining XCIP clonality testing with genetic clonality testing to identify clonal populations with yet-to-be-discovered genetic changes.
Reversal of autoimmune disease in lupus-prone New Zealand black/New Zealand white mice by nonmyeloablative transplantation of purified allogeneic hematopoietic stem cells
Authors: Smith-Berdan Stephanie , Gille Daphne , Weissman Irving L. , Christensen Julie L.
Published: April 2007

Patients with severe systemic lupus erythematosus (SLE) refractory to conventional treatment are candidates for autologous hematopoietic stem cell (HSC) transplantation if the intent is to reset the immunologic clock. These patients might be candidates for allotransplantation with (SLE)-resistant major histocompatibility complex (MHC) haplotype-matched HSC if partial or complete replacement of an autoimmune-prone system is the intent. Using lupus-prone New Zealand black × New Zealand white (NZBW) mice, we investigated the use of highly enriched, haplomismatched, allogeneic HSC to prevent development of or to treat established autoimmune pathology. Young NZBW mice receiving purified allogeneic HSC transplants had improved survival, decreased proteinuria, circulating immune complexes, and autoantibodies to nuclear antigens than did untreated mice or mice given NZBW HSCs. NZBW mice with established lupus-like disease that received nonmyeloablative conditioning and transplants of (MHC) haplomismatched allogeneic HSCs also had greatly increased overall survival. Mice that received transplants exhibited stabilization or reversal of their lupus symptoms; stabilized or decreased proteinuria, and a lower frequency of elevated circulating immune complexes or autoantibodies than did control mice. Induction of durable mixed chimerism by transplantation of purified allogeneic HSCs after nonmyeloablative conditioning has the potential to reverse symptoms of established NZBW lupus.
A Comparative Study of Seismic Provisions between the International Building Code 2003 and Mexico's Manual of Civil Works 1993
Authors: Pong Wenshen , Gannon Glenn A. , Lee Zu-Hsu
Published: April 2007

This study focuses on the differences and similarities between the seismic provisions of the International Building Code 2003 (IBC 2003) and Mexico's Manual of Civil Works for Seismic Design (MOC-93). A six-story special reinforced concrete moment frame building was chosen to explore how the static force procedures of both codes differed. The sample location of this building was the San Diego/Tijuana border region. A total of four random soil shear wave velocities were chosen to identify the necessary IBC 2003 soil site classes and MOC-93 soil types. Inelastic design response spectra were established based on the 4 soil shear wave velocities. When the results were compared, several conclusions were evident. The IBC 2003 design response spectra may be more accurate for the studied region of San Diego, California, USA and Tijuana, Baja California, based on the probabilistic data of the region. The MOC-93 design response spectra, which include longer periods and higher seismic coefficients in most cases, are based on deterministic and probabilistic data that is heavily influenced by subduction source earthquakes that occur along Mexico's central Pacific Coast.
Working Mechanism of Single-Layer Cable Net Supported Glass Curtain Walls
Authors: Feng Ruo-Qiang , Wu Yue , Shen Shi-Zhao
Published: April 2007

In this paper experiments and numerical simulations were undertaken to investigate the working mechanism of single-layer cable net supported glass curtain walls. We brought out the feasible ways in which glass panels work in coordination with the cable net, and verified by experiments. A parameter study was used to analyze the influence of factors, such as cable pretension, severity of loading, cable diameter, glass thickness and glass mesh size, on how glass panels worked in coordination with the cable net. The results indicate that the bending stiffness of the glass panel has little effect on the deflection of the structure, and the stiffness contribution of glass panels to the structure is substantially decided by the glass face membrane action. This action depends on the deflections of the glass panel and cable net.
Experimental and Numerical Study on Pounding Effects and Mitigation Techniques for Adjacent Structures
Authors: Rezavandi A. , Moghadam A.S.
Published: April 2007

Pounding of adjacent buildings has been a major cause of building damages in the past earthquakes. In this study, two series of shaking table experiments on small scale moment resisting one-bay frames subjected to harmonic excitation and seismic time histories are described. A series of tests on techniques of reduction the effects of pounding are also presented. They are increase in distance of the buildings, application of impact absorbing material and connecting the two buildings together. The results of experiments and analyses indicate both the effectiveness and problems associated with each method of reducing pounding effects. It was found that the impacts absorbing materials were found to be very effective in reducing pounding effect and the responses of frames were very sensitive to the gap between them.
Flexural Fatigue Strength of Steel Fibrous Concrete Beams
Authors: Singh Surinder P , Sharma Umesh K
Published: April 2007

The paper presents results of an investigation conducted to study the fatigue strength of steel fibre reinforced concrete (SFRC) beams in flexure. An experimental programme was planned in which about two hundred and thirty three flexural fatigue tests were conducted at different stress levels and stress ratios to obtain the fatigue lives of SFRC containing different volume fractions of steel fibres. One hundred and sixty six complimentary static flexural tests were also conducted to obtain the static flexural strength of SFRC beams prior to fatigue testing. The specimens of size 100 × 100 × 500 mm were used for static flexural as well as flexural fatigue tests and incorporated 0.5, 1.0 and 1.5% volume fraction of corrugated steel fibres of size 0.6 × 2.0 × 30 mm. The concept of equivalent fatigue life was then applied to the fatigue life data to incorporate the effects of stress level, stress ratio and survival probability into the fatigue equation. The results indicate that the distribution of equivalent fatigue life of SFRC can approximately be described by the two-parameter Weibull distribution. The material coefficients of the fatigue equation have been determined corresponding to different survival probabilities so that the fatigue equation can be used to predict the flexural fatigue strength of SFRC.
Rhetorically self‐sufficient arguments in Western Australian parliamentary debates on Lesbian and Gay Law Reform
Authors: Summers Mark
Published: April 2007

Western Australia's Acts Amendment (Lesbian and Gay Law Reform) Bill 2001 delivered a measure of legal equality in such areas as property transfer, superannuation, inheritance and discrimination, and more controversially, adoption, lesbian access to IVF, lowering the age of consent for sex between men from 21 to 16, and incorporating information on homosexuality into high school sex education classes. This paper examines the use of various moral principles within parliamentary speeches supporting or opposing the legislation, and the extent to which they were treated by members as beyond question, or ‘rhetorically self‐sufficient’. The resources of ‘equality’, ‘human rights’, ‘democracy’, ‘the interests of the majority’ and ‘the interests of children’ were given a kind of beyond‐question, self‐sufficient status, but their use was able to be undermined in a number of ways, relating to members' management of what the Bill was ‘about’, and the flexibility of these social constructs. It is argued that rather than pitting one set of resources against another, members on both sides of the debate faced a rhetorical pressure to adopt and mobilize all of the same self‐sufficient moral resources, due to the flexible, constructed and non‐hierarchical, yet often rhetorically self‐sufficient nature of common‐sense moral principles.