bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recipient inflammation affects the frequency and magnitude of immunization to transfused red blood cells
Authors: Hendrickson Jeanne E. , Desmarets Maxime , Deshpande Seema S. , Chadwick Traci E. , Hillyer Christopher D. , Roback John D. , Zimring James C. 
Published: September 2006

BACKGROUND: Most alloantigens on transfused red blood cells (RBCs) are weakly immunogenic, with only a 2 to 6 percent overall immunization rate even in patients receiving multiple transfusions. Although recipient genetics may contribute to responder and/or nonresponder status, in most cases HLA type does not predict humoral response to RBC antigens. In contrast, rates of alloimmunization do correspond to the underlying disease status of transfusion recipients, suggesting that acquired host factors may play an important role. In this context, it was hypothesized that the inflammatory status of a transfusion recipient would influence immunization to transfused RBCs.STUDY DESIGN AND METHODS: A novel murine model for alloimmunization to RBC antigens was developed with the mHEL mouse, which expresses hen egg lysozyme (HEL) as a model blood group antigen. Leukoreduced mHEL RBCs were transfused into wild‐type recipient mice, and anti‐HEL responses were monitored. To test the stated hypothesis, some recipient animals were injected with polyinosinic polycytidylic acid (poly(I:C)), a synthetic double‐stranded RNA molecule that induces viral‐like inflammation.RESULTS: Similar to the immunogenicity of most RBC antigens in humans, transfusion of mHEL RBCs into uninflamed mice was only a weak immunogen. In contrast, poly(I:C)‐treated mice had a significant increase in both the frequency and the magnitude of alloimmunization to the mHEL antigen.CONCLUSIONS: These findings demonstrate that recipient inflammation with poly(I:C) significantly enhances humoral immunization to transfused alloantigens in a murine model. Moreover, these data suggest that the inflammatory status of human transfusion recipients may regulate the immunogenicity of transfused RBCs.
Clinical and immunohistochemical assessment of the effect of cyclosporin in keratinocytes and dermal dendrocytes in psoriasis
Authors: Lago Eduardo , Carneiro Sueli , Cuzzi Tullia , Magalhães Geraldo , Cássia Flavia , Pessanha Fátima , Ramos‐e‐Silva Marcia 
Published: September 2006

Background:  Cyclosporine is a potent immunosupressor, which induces cytokeratin expression pattern changes and dermal dendrocytes number increase.Objectives:  To evaluate its clinical effect in psoriasis, on keratinocytic proliferation and differentiation, and on dermal dendrocytes proliferation.Methods:  Thirty patients with psoriasis were treated and evaluated for 8 weeks. Clinical improvement was evaluated by Psoriasis Area and Severity Index (PASI). Biopsies were performed initially and after 8 weeks. Immunohistochemistry [CK markers 10, 14, and 16, and factor XIIIa+ (FXIIIa+)] was performed.Results:  Mean PASI before treatment was 26.32 and 3.71 after. Mean initial and final PASI difference was 22.61 (p < 0.001). Two patients had serum creatinine and six uric acid increase. Before and after treatment, mean numbers per field of dermal dendrocytes were 7.07 and 3.68, respectively. Mean difference was 3.39, with p < 0.001. CK10 immunohistochemical pattern demonstrated recovery of normal expression pattern in 26 patients, while CK14 pattern demonstrated improvement in 21 patients.Conclusions:  Cyclosporine was effective and safe for psoriasis in low doses, with significant decrease of PASI and dermal dendrocytes number after 8 weeks of therapy. CK10 and 14 pattern changed and, less prominently, CK16 expression. These modifications occur later than the PASI and dermal dendrocytes variation.
Comparison of two hydroxyethyl starch 200/0.5 formulations with regard to hemorheology, coagulation and elimination kinetics
Authors: GOPINATH RAMACHANDRAN , KAUL SUBHASH 
Published: September 2006

SUMMARYObjective:  To compare the elimination kinetics and the effects on coagulation of two hydroxyethyl starch (HES) preparations with identical labeling.Methods:  Two formulations of 6% HES 200/0.5 [HAES‐steril™, Fresenius Kabi, India (group A) and HESTAR‐200™, Claris Lifesciences, India (group B)] were compared in a randomized, double‐blind, prospective study in 22 stroke patients receiving HES for therapeutic hemodilution over 10 days.Results:  Mean in vivo molecular weight (Mw) of HES on day 6 was 98,036 ± 5631 Da in group A and 157,254 ± 5200 Da in group B (P < 0.0001). On day 11 these values were 102,727 ± 4440 Da and 146,856 ± 9006 Da in group A and group B, respectively (P = 0.0002). From day 2 to day 11, plasma HES concentrations were significantly higher in group B than in group A (P < 0.05). Group A showed less thromboelastographic abnormalities.Conclusion:  Two HES formulations with similar Mw and degree of substitution should not be considered equivalent based on label claims only.
Platelet biology – an overview
Authors: KICKLER THOMAS S. 
Published: September 2006

SUMMARYUnderstanding the biology of platelet is important for one to treat patients with acquired or inherited platelet disorders. Platelets provide primary hemostasis by performing five primary functions: adhesion, aggregation, secretion, and providing procoagulant surface and clot retraction. The elucidation of the molecular mechanisms carrying out these functions has led to a better understanding of the pathophysiology of bleeding and the development of new approaches in treating patients with qualitative and quantitative platelet disorders. The purpose of this review is to provide a foundation for understanding the other papers in this publication on the treatment of platelet disorders.
Immunoglobulin G, A, and M Responses to BK Virus in Renal Transplantation
Authors: Randhawa Parmjeet S. , Gupta Gaurav , Vats Abhay , Shapiro Ron , Viscidi Raphael P. 
Published: September 2006

ABSTRACT

Immunoglobulin G (IgG), IgA, and IgM antibodies were measured in serum samples from 71 organ donors, 81 kidney transplant recipients at transplantation, and 67 patients during the posttransplant period by using a virus-like particle-based enzyme-linked immunosorbent assay (ELISA). BK virus (BKV) and JC virus DNA were detected in urine and plasma by real-time PCR. IgG antibodies to BKV were demonstrated in the majority (80.3 to 100%) of patients irrespective of clinical category, but titers were highest in patients with active viral replication. IgA antibodies were present with greater frequency (72.7 to 81.3% versus 0 to 23.6%;
P
< 0.001) and higher titer (mean optical density, 0.11 to 0.15 versus 0.05 to 0.08;
P
< 0.001) in patients who were BKV DNA positive than those who were BKV DNA negative. IgM antibodies showed a similar pattern of reactivity but lower frequency in the setting of active viral replication (9.1 to 43.7% versus 0 to 1.4%;
P
< 0.001). A rise in IgG level of >0.577 optical density (OD) units or a rise in IgA or IgM level of >0.041 OD units was strongly associated with active viral replication. Urine viral load showed a positive correlation with IgM titer (
r
= 0.22) but a negative correlation with IgG titer (
r
= −0.28) and IgA titer (
r
= −0.1). Chronic dialysis patients typically did not have serologic or virologic evidence of active BKV infection. Anti-BKV titers did not rise in patients with JC viruria. In conclusion, measurement of anti-BKV antibody titer and class response can be used to detect the onset of viral replication. ELISAs can be quite specific despite considerable sequence homology between BK virus and JC virus.
Functional Characterization of IS
1999
, an IS
4
Family Element Involved in Mobilization and Expression of β-Lactam Resistance Genes
Authors: Aubert Daniel , Naas Thierry , Héritier Claire , Poirel Laurent , Nordmann Patrice 
Published: September 2006

ABSTRACT

IS
1999
and a point mutant derivative, IS
1999.2
, have been described inserted upstream of emerging antibiotic resistance genes
bla
VEB-1
and
bla
OXA-48
. 5′ Rapid amplification of cDNA ends experiments revealed that expression of these β-lactamase genes was driven by the outward-directed promoter, P
out
, located in the IS
1999
elements. These findings led us to study IS
1999
-mediated gene mobilization. Thus, the transposition properties of IS
1999
and of IS
1999
-based composite transposons, made of two copies of IS
1999
in different orientations, were investigated. IS
1999
or IS
1999
-based composite transposons were capable of transposing onto the conjugative plasmid pOX38-Gen. Sequence analysis of the insertion sites revealed that IS
1999
inserted preferentially into DNA targets containing the consensus sequence NGCNNNGCN. Transposition was more efficient when at least one left inverted repeat end was located at an outside end of the transposon. The transposition frequency of IS
1999.2
was 10-fold lower than that of IS
1999
, and transposition frequencies of the putative natural transposon, Tn
1999
, were below detection limits of our transposition assay. This reduced transposition frequency of IS
1999.2
-based elements may result from a lower transcription of the transposase gene, as revealed by reverse transcription-PCR analyses.
Hypoxanthine Incorporation Is Nonmutagenic in
Escherichia coli
Authors: Budke Brian , Kuzminov Andrei 
Published: September 2006

ABSTRACT

Endonuclease V, encoded by the
nfi
gene, initiates removal of the base analogs hypoxanthine and xanthine from DNA, acting to prevent mutagenesis from purine base deamination within the DNA. On the other hand, the RdgB nucleotide hydrolase in
Escherichia coli
is proposed to prevent hypoxanthine and xanthine incorporation into DNA by intercepting the noncanonical DNA precursors dITP and dXTP. Because many base analogs are mutagenic when incorporated into DNA, it is intuitive to think of RdgB as acting to prevent similar mutagenesis from deaminated purines in the DNA precursor pools. To test this idea, we used a set of Claire Cupples' strains to detect changes in spontaneous mutagenesis spectra, as well as in nitrous acid-induced mutagenesis spectra, in wild-type cells and in
rdgB
single,
nfi
single, and
rdgB nfi
double mutants. We found neither a significant increase in spontaneous mutagenesis in
rdgB
and
nfi
single mutants or the double mutant nor any changes in nitrous acid-induced mutagenesis for
rdgB
mutant strains. We conclude that incorporation of deaminated purines into DNA is nonmutagenic.
Characterization of Stg Fimbriae from an Avian Pathogenic
Escherichia coli
O78:K80 Strain and Assessment of Their Contribution to Colonization of the Chicken Respiratory Tract
Authors: Lymberopoulos Maria H. , Houle Sébastien , Daigle France , Léveillé Simon , Brée Annie , Moulin-Schouleur Maryvonne , Johnson James R. , Dozois Charles M. 
Published: September 2006

ABSTRACT

In a previous study,
ecs-3
, a sequence from avian pathogenic
Escherichia coli
(APEC) O78:K80 strain χ7122, was found to be expressed in vivo in infected chicken tissues. The region encompassing
ecs-3
carries a fimbrial gene cluster that is a putative ortholog of the
stg
fimbrial gene cluster of
Salmonella enterica
serovar Typhi. This APEC fimbrial gene cluster, which we have termed
stg
, is a member of a distinct group of related fimbriae that are located in the
glmS
-
pstS
intergenic region of certain
E. coli
and
S. enterica
strains. Under the control of the pBAD promoter, the production of Stg fimbriae was demonstrated by Western blotting and immunogold electron microscopy with
E. coli
K-12. Transcriptional fusions suggest that
stg
expression is influenced by the carbohydrate source and decreased by the addition of iron and that Fur plays a role in the regulation of
stg
expression.
stg
sequences were associated with APEC O78 isolates, and
stg
was phylogenetically distributed among
E. coli
reference strains and clinical isolates from human urinary tract infections. Stg fimbriae contributed to the adherence of a nonfimbriated
E. coli
K-12 strain to avian lung sections and human epithelial cells in vitro. Coinfection experiments with APEC strain χ7122 and an isogenic Δ
stg
mutant demonstrated that compared to the wild-type parent, the Δ
stg
mutant was less able to colonize air sacs, equally able to colonize lungs, and able to more effectively colonize tracheas of infected chickens. Stg fimbriae, together with other adhesins, may therefore contribute to the colonization of avian respiratory tissues by certain APEC strains.
Identification of a Novel Galactosyl Transferase Involved in Biosynthesis of the Mycobacterial Cell Wall
Authors: Mikušová Katarína , Beláňová Martina , Korduláková Jana , Honda Kristine , McNeil Michael R. , Mahapatra Sebabrata , Crick Dean C. , Brennan Patrick J. 
Published: September 2006

ABSTRACT

The possibility of the Rv3782 protein of
Mycobacterium tuberculosis
being a putative galactosyl transferase (GalTr) implicated in galactan synthesis arose from its similarity to the known GalTr Rv3808c, its classification as a nucleotide sugar-requiring inverting glycosyltransferase (GT-2 family), and its location within the “possible arabinogalactan biosynthetic gene cluster” of
M. tuberculosis.
In order to study the function of the enzyme, active membrane and cell wall fractions from
Mycobacterium smegmatis
containing the overexpressed Rv3782 protein were incubated with endogenous decaprenyldiphosphoryl-
N
-acetylglucosaminyl-rhamnose (C
50
-P-P-GlcNAc-Rha) as the primary substrate for galactan synthesis and UDP-[
14
C]galactopyranose as the immediate precursor of UDP-[
14
C]galactofuranose, the ultimate source of all of the galactofuranose (Gal
f
) units of galactan. Obvious increased and selective synthesis of C
50
-P-P-GlcNAc-Rha-Gal
f-
Gal
f
, the earliest product in the pathway leading to the fully polymerized galactan, was observed, suggesting that Rv3782 encodes a GalTr involved in the first stages of galactan synthesis. Time course experiments pointed to a possible bifunctional enzyme responsible for the initial synthesis of C
50
-P-P-GlcNAc-Rha-Gal
f
, followed by immediate conversion to C
50
-P-P-GlcNAc-Rha-Gal
f-
Gal
f
. Thus, Rv3782 appears to be the initiator of galactan synthesis, while Rv3808c continues with the subsequent polymerization events.
Localized Induction of the
ntcA
Regulatory Gene in Developing Heterocysts of
Anabaena
sp. Strain PCC 7120
Authors: Olmedo-Verd Elvira , Muro-Pastor Alicia M. , Flores Enrique , Herrero Antonia 
Published: September 2006

ABSTRACT

The
ntcA
gene encodes an N-control transcriptional regulator in cyanobacteria. In the N
2
-fixing, heterocyst-forming cyanobacterium
Anabaena
sp. strain PCC 7120,
ntcA
is an autoregulatory gene that is transcribed from a complex promoter region that includes a constitutive promoter (P
2
) and promoters that are induced upon N step-down (P
1
and P
3
). Expression of
ntcA
was investigated with the use of an
ntcA-gfp
translational fusion, which was introduced both in the natural
ntcA
locus and in a heterologous genomic place. Induction of
ntcA-gfp
took place after N step-down in all the cells of the filament, but at especially high levels in developing heterocysts. Localized induction could be driven independently by P
3
and P
1
.
Both Subunits of ATP-Citrate Lyase fromChlorobium tepidumContribute to Catalytic Activity
Authors: Kim Wonduck , Tabita F. Robert 
Published: September 2006

ABSTRACTATP-citrate lyase (ACL) is an essential enzyme of the reductive tricarboxylic acid (RTCA) pathway of CO2assimilation. The RTCA pathway occurs in several groups of autotrophic prokaryotes, including the green sulfur bacteria. ACL catalyzes the coenzyme A (CoA)-dependent and MgATP-dependent cleavage of citrate into oxaloacetate and acetyl-CoA, representing a key step in the RTCA pathway. To characterize this enzyme from the green sulfur bacteriumChlorobium tepidumand determine the role of its two distinct polypeptide chains, recombinant holo-ACL as well as its two individual subunit polypeptides were synthesized inEscherichia coli. The recombinant holoenzyme, prepared from coexpressed large and small ACL genes, and the individual large and small subunit polypeptides, prepared from singly expressed genes, were all purified to homogeneity to high yield. Purified recombinant holo-ACL was isolated at high specific activity, and itskcatwas comparable to that of previously prepared nativeC. tepidumACL. Moreover, the purified recombinant large and small subunit polypeptides were able to reconstitute the holo-ACL in vitro, with activity levels approaching that of recombinant holo-ACL prepared from coexpressed genes. Stoichiometric amounts of each subunit protein were required to maximize the activity and form the most stable structure of reconstituted holo-ACL. These results suggested that this reconstitution system could be used to discern the catalytic role of specific amino acid residues on each subunit. Reconstitution and mutagenesis studies together indicated that residues of each subunit contributed to different aspects of the catalytic mechanism, suggesting that both subunit proteins contribute to the active site ofC. tepidumACL.
Tungsten Transport Protein A (WtpA) inPyrococcus furiosus: the First Member of a New Class of Tungstate and Molybdate Transporters
Authors: Bevers Loes E. , Hagedoorn Peter-Leon , Krijger Gerard C. , Hagen Wilfred R. 
Published: September 2006

ABSTRACTA novel tungstate and molybdate binding protein has been discovered from the hyperthermophilic archaeonPyrococcus furiosus. This tungstate transport protein A (WtpA) is part of a new ABC transporter system selective for tungstate and molybdate. WtpA has very low sequence similarity with the earlier-characterized transport proteins ModA for molybdate and TupA for tungstate. Its structural gene is present in the genome of numerous archaea and some bacteria. The identification of this new tungstate and molybdate binding protein clarifies the mechanism of tungstate and molybdate transport in organisms that lack the known uptake systems associated with the ModA and TupA proteins, like many archaea. The periplasmic protein of this ABC transporter, WtpA (PF0080), was cloned and expressed inEscherichia coli. Using isothermal titration calorimetry, WtpA was observed to bind tungstate (dissociation constant [KD] of 17 ± 7 pM) and molybdate (KDof 11 ± 5 nM) with a stoichiometry of 1.0 mol oxoanion per mole of protein. These lowKDvalues indicate that WtpA has a higher affinity for tungstate than do ModA and TupA and an affinity for molybdate similar to that of ModA. A displacement titration of molybdate-saturated WtpA with tungstate showed that the tungstate effectively replaced the molybdate in the binding site of the protein.
Hundreds of Flagellar Basal Bodies Cover the Cell Surface of the Endosymbiotic Bacterium
Buchnera aphidicola
sp. Strain APS
Authors: Maezawa Kazuki , Shigenobu Shuji , Taniguchi Hisaaki , Kubo Takeo , Aizawa Shin-ichi , Morioka Mizue 
Published: September 2006

ABSTRACT

Buchnera aphidicola
is the endosymbiotic bacterium of the pea aphid. Due to its small genome size,
Buchnera
lacks many essential genes for autogenous life but obtains nutrients from the host. Although the
Buchnera
cell is nonmotile, it retains clusters of flagellar genes that lack the late genes necessary for motility, including the flagellin gene. In this study, we show that the flagellar genes are actually transcribed and translated and that the
Buchnera
cell surface is covered with hundreds of hook-basal-body (HBB) complexes. The abundance of HBB complexes suggests a role other than motility. We discuss the possibility that the HBB complex may serve as a protein transporter not only for the flagellar proteins but also for other proteins to maintain the symbiotic system.
Identification and Characterization of the Chemotactic Transducer in
Pseudomonas aeruginosa
PAO1 for Positive Chemotaxis to Trichloroethylene
Authors: Kim Hye-Eun , Shitashiro Maiko , Kuroda Akio , Takiguchi Noboru , Ohtake Hisao , Kato Junichi 
Published: September 2006

ABSTRACT

Pseudomonas aeruginosa
PAO1 is repelled by trichloroethylene (TCE), and the methyl-accepting chemotaxis proteins PctA, PctB, and PctC serve as the major chemoreceptors for negative chemotaxis to TCE. In this study, we found that the
pctABC
triple mutant of
P. aeruginosa
PAO1 was attracted by TCE. Chemotaxis assays of a set of mutants containing deletions in 26 potential
mcp
genes revealed that
mcpA
(PA0180) is the chemoreceptor for positive chemotaxis to TCE. McpA also detects tetrachloroethylene and dichloroethylene isomers as attractants.
Expression of the Primary Carbohydrate Component of the
Bordetella bronchiseptica
Biofilm Matrix Is Dependent on Growth Phase but Independent of Bvg Regulation
Authors: Irie Yasuhiko , Preston Andrew , Yuk Ming H. 
Published: September 2006

ABSTRACT

We previously showed that the Bvg virulence control system regulates biofilm formation in
Bordetella bronchiseptica
(Y. Irie, S. Mattoo, and M. H. Yuk, J. Bacteriol.
186:
5692-5698, 2004). Analyses of the extracellular components of
B. bronchiseptica
biofilm matrix revealed that the major sugar component in the matrix was xylose, and linkage analysis indicated a majority of it to be in a 4-linked polymeric form. The production of xylose was independent of Bvg regulation but instead was dependent on bacterial growth phase. In addition,
N
-acetyl-glucosamine in the matrix was found to be important for the initial development of the biofilm. These results suggest that
B. bronchiseptica
biofilm formation is growth phase dependent in addition to being regulated by the Bvg virulence system.
Characterization of Ferric and Ferrous Iron Transport Systems inVibrio cholerae
Authors: Wyckoff Elizabeth E. , Mey Alexandra R. , Leimbach Andreas , Fisher Carolyn F. , Payne Shelley M. 
Published: September 2006

ABSTRACTVibrio choleraehas multiple iron acquisition systems, including TonB-dependent transport of heme and of the catechol siderophore vibriobactin. Strains defective in both of these systems grow well in laboratory media and in the infant mouse intestine, indicating the presence of additional iron acquisition systems. Previously uncharacterized potential iron transport systems, including a homologue of the ferrous transporter Feo and a periplasmic binding protein-dependent ATP binding cassette (ABC) transport system, termed Fbp, were identified in theV. choleraegenome sequence. Clones encoding either the Feo or the Fbp system exhibited characteristics of iron transporters: both repressed the expression oflacZcloned under the control of a Fur-regulated promoter inEscherichia coliand also conferred growth on aShigella flexnerimutant that has a severe defect in iron transport. Two other ABC transporters were also evaluated but were negative by these assays. Transport of radioactive iron by the Feo system into theS. flexneriiron transport mutant was stimulated by the reducing agent ascorbate, consistent with Feo functioning as a ferrous transporter. Conversely, ascorbate inhibited transport by the Fbp system, suggesting that it transports ferric iron. The growth ofV. choleraestrains carrying mutations in one or more of the potential iron transport genes indicated that both Feo and Fbp contribute to iron acquisition. However, a mutant defective in the vibriobactin, Fbp, and Feo systems was not attenuated in a suckling mouse model, suggesting that at least one other iron transport system can be used in vivo.