bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of platelet mitochondria integrity after treatment with Mirasol pathogen reduction technology
Authors: Li Junzhi , Lockerbie Owen , De Korte Dirk , Rice Joe , McLean Robyn , Goodrich Raymond P. 
Published: June 2005

BACKGROUND:Previous studies showed that Mirasol (Navigant Biotechnologies, Inc.) pathogen reduction technology (PRT) treatment resulted in an increase in platelet (PLT) glucose consumption and lactate production rates and decrease in pH in media during PLT storage. Increased glycolytic flux could result from damage to mitochondria and/or increased ATP consumption.STUDY DESIGN AND METHODS:PLT concentrates were collected by standard automated blood component collection system (Trima, Gambro BCT) procedure on Day 0 and treated with Mirasol PRT treatment on Day 1. PLT mitochondrial transmembrane potential was evaluated by staining PLTs with JC‐1 followed by flow cytometry analysis. Mitochondrial enzymatic activity was measured by the MTT assay. ATP content and pH were also quantified. The values for these measurements were compared among control, untreated, and pathogen reduction technology (PRT)‐treated PLTs during PLT storage for up to 7 days.RESULTS:No significant changes were found in pH, JC‐1 signal, MTT activity, and ATP content of the PLTs immediately after PRT treatment. The treated PLTs exhibited a moderate but significantly accelerated decrease in pH and lower ATP content after 7‐day storage when compared to control PLTs. Neither the JC‐1 assay nor the MTT assay, however, showed a significant difference between control and treated PLTs during PLT storage.CONCLUSIONS:There is no evidence from these studies that Mirasol PRT treatment alters PLT mitochondrial structural and functional integrity immediately after treatment and during PLT storage. An increased demand for ATP may be the driving force for observed increases in both the glycolytic flux and the oxidative metabolism observed in treated PLTs.
Dynamics of viremia in early hepatitis C virus infection
Authors: Glynn Simone A. , Wright David J. , Kleinman Steven H. , Hirschkorn Dale , Tu Yongling , Heldebrant Charles , Smith Richard , Giachetti Cristina , Gallarda James , Busch Michael P. 
Published: June 2005

BACKGROUND: It is important to characterize viral dynamics in early hepatitis C virus (HCV) infection to further our understanding of viral pathogenesis and the potential for secondary transmission in acute infection through blood transfusion or other routes.STUDY DESIGN AND METHODS: Serial units given by 77 source plasma donors who had evolved from HCV RNA–negative to HCV RNA–positive by nucleic acid amplification technology (NAT) screening with 512‐unit pool‐NAT or were followed from RNA detection to antibody conversion were tested by individual NAT and quantitative RNA assays.RESULTS: During the ramp‐up phase when exponential growth occurs, HCV viral load doubled every 10.8 hours (95% confidence interval [CI], 9.9‐12.0). Intermittent viremia was observed before the ramp‐up phase in 37 of 50 panels with the earliest detectable viremic bleed occurring 63 days before the estimated onset of ramp‐up. The plateau phase or high‐titer viremic period that occurs between ramp‐up and seroconversion was estimated to last 56.3 days (95% CI, 44.8‐67.8).CONCLUSIONS: Intermittent low‐level HCV viremia can occur as much as 2 months before the periods of exponential increase in viral load and the high‐titer plateau‐phase viremia that usually precede seroconversion. Animal inoculation studies are in progress to evaluate if transfusion of low‐level viremic plasma can transmit HCV infection.
Non‐transferrin‐bound iron in platelet concentrates promotes the growth of Staphylococcus epidermidis
Authors: Matinaho Sanna , Parkkinen Jaakko 
Published: June 2005

BACKGROUND: Staphylococcus epidermidis, the most common organism implicated in bacterial contamination of platelet (PLT) concentrates (PCs), does not grow in serum unless transferrin is fully saturated and there is non‐transferrin‐bound iron (NTBI) available. Here, the occurrence and origin of NTBI in PCs has been studied.STUDY DESIGN AND METHODS: NTBI in PC supernatants was determined by a chelation method and by the bleomycin‐detectable iron assay. Iron binding by transferrin was determined by spectrophotometry, and transferrin iron forms, by urea gel electrophoresis. The growth of inoculated S. epidermidis in PC supernatants was monitored by optical density and determination of viable counts.RESULTS: PCs contained approximately 0.14 µmol per L redox‐active iron measured by the bleomycin assay and approximately 0.7 µmol per L NTBI by the chelation method. As a further indication of the presence of NTBI, the growth of S. epidermidis in the PC supernatants was inhibited by iron chelation with deferoxamine. Transferrin in the PC medium was only partially saturated with iron, and the reason for the presence of NTBI was found to be impaired iron binding by transferrin. Iron was displaced from transferrin by citrate at molar ratios to transferrin that occur in citrated plasma and in PLT additive solution (AS). Citrated plasma supported the growth of S. epidermidis whereas serum did not.CONCLUSIONS: PCs stored in plasma or AS contain a low level of NTBI because of the displacement of iron from plasma‐derived transferrin by citrate. NTBI in the PC medium supports the growth of S. epidermidis.
Formation and resolution of ankylosis under application of recombinant human bone morphogenetic protein‐2 (rhBMP‐2) to class III furcation defects in cats
Authors: Takahashi D. , Odajima T. , Morita M. , Kawanami M. , Kato H. 
Published: June 2005

Objectives:  Periodontal regeneration under application of bone morphogenetic protein (BMP) is compromised by ankylosis. Ankylosis disappearance following application of BMP has been observed in the case of a small defect, which might be beneficial change for periodontal regeneration. However, the histological observation of ankylosis disappearance has not been demonstrated in a large defect. The purpose of this present study was to confirm resolution of ankylosis during periodontal regeneration by recombinant human BMP‐2 (rhBMP‐2) applied to class III furcation defects.Material and methods:  Class III furcation defects were created in the premolars of six adult cats. The rhBMP‐2 material, prepared by applying rhBMP‐2 to a combination of polylactic acid–polygricolic copolymer and gelatin sponge (PGS; 0.33 µg rhBMP‐2/mm3 PGS) or control material containing only PGS, was implanted into each defect. The cats were killed at 3, 6 or 12 weeks after surgery and serial sections were prepared for histological and histometrical observation.Results:  Ankylosis was observed in some of the rhBMP‐2/PGS group at 3 and 6 weeks, but not at 12 weeks. At 6 weeks, osteoclast‐like cells were visible in the rhBMP‐2/PGS group with ankylosis. Residual PGS was evident between the bone and root surface in the rhBMP‐2/PGS group without ankylosis at 3 weeks.Conclusions:  Resolution of ankylosis by osteoclast‐like cells possibly occurred under application of rhBMP‐2. Residual PGS might play an important role in preventing ankylosis formation.
Distinctive localization and function for lumican, fibromodulin and decorin to regulate collagen fibril organization in periodontal tissues
Authors: Matheson S. , Larjava H. , Häkkinen L. 
Published: June 2005

Background:  Small leucine‐rich proteoglycans (SLRPs) decorin, biglycan, fibromodulin and lumican are secreted extracellular matrix molecules that associate with fibrillar collagens and regulate collagen fibrillogenesis. Collagens are the major extracellular matrix components of periodontal connective tissues where they provide mechanical attachment of the tooth to the bone and gingiva and mediate signals that regulate cell functions, including remodeling of the periodontal ligament and bone. Structural organization of collagen may also be important for the defense against periodontal disease, because in certain conditions abnormal collagen fibrils associate with increased susceptibility to periodontal disease.Objectives:  The purpose of this study was to find out the role of SLRPs to regulate collagen fibril and fibril bundle formation in periodontal tissues.Methods:  The localization of SLRPs in human and mouse periodontal tissues was studied using immunohistochemical methods. To assess the function of SLRPs we studied periodontal tissues of mice harboring targeted deletions of decorin, fibromodulin or lumican genes and lumican and fibromodulin double knockout mice using histological and electronmicroscopical methods.Results:  The SLRPs were coexpressed in human and mouse gingival and periodontal ligament connective tissues where they colocalized with collagen fibril bundles. Teeth in the knockout animals were fully erupted and showed normal gross morphology. Targeted deletion of decorin, fibromodulin, lumican or both lumican and fibromodulin resulted in abnormal collagen fibril and fibril bundle morphology that was most evident in the periodontal ligament. Each of the gene deletions resulted in a unique fibril and fibril bundle phenotype.Conclusions:  These findings indicate that decorin, fibromodulin and lumican coordinately regulate the fibrillar and suprafibrillar organization of collagen in the periodontal ligament.
Parenting Skills Training: An Effective Intervention for Internalizing Symptoms in Younger Children?
Authors: Cartwright‐Hatton Sam , McNally Deborah , White Caroline , Verduyn Chrissie 
Published: June 2005

PROBLEM:  A number of interventions are effective in treating older children with internalizing symptoms. However, little is known about the efficacy of psychological interventions in treating younger children. This study examined the impact on internalizing symptoms of a parenting skills training program. METHODS:  Forty‐three parents took part in a parenting skills training program. Externalizing and internalizing behaviors were measured before and after treatment and after a 6‐month period. FINDINGS:  Externalizing symptoms fell after treatment. Interestingly, internalizing scores fell to an approximately equivalent degree. CONCLUSIONS:  An intervention targeted towards parenting may be efficacious in the treatment of children's internalizing symptoms.
The Use of Selective Serotonin Reuptake Inhibitors in Children and Adolescents with Major Depression
Authors: Scahill Lawrence , Hamrin Vanya , Pachler Mary Ellen 
Published: June 2005

TOPIC:  Recent warnings about suicidal thoughts and self‐injurious behavior in youth treated with selective serotonin reuptake inhibitors raise fundamental questions about the risk–benefit ratio of this class of medications. METHODS:  Data from placebo‐controlled trials are used to elucidate the potential risks and benefits of the selective serotonin reuptake inhibitors (SSRIs) in children and adolescent with major depression. This analysis forms the basis of clinical recommendations. SOURCES:  The review includes the six large‐scale, placebo‐controlled trials that have been published over the past decade. These data were augmented by information from regulatory hearings in 2003–2004 and selected open‐label reports. CONCLUSIONS:  Emerging data from several clinical trials show that the SSRIs have modest effects on childhood depression. In addition, SSRI treatment may be associated with behavioral activation, self‐harm, and suicidal ideation. Appropriate use of SSRIs in children and adolescents requires careful diagnostic assessment, evaluation of co‐occurring conditions, and diligent monitoring, especially within the first weeks of treatment.
Homocysteine Toxicity inEscherichia coliIs Caused by a Perturbation of Branched-Chain Amino Acid Biosynthesis
Authors: Tuite Nina L. , Fraser Katy R. , O'Byrne Conor P. 
Published: June 2005

ABSTRACTInEscherichia colithe sulfur-containing amino acid homocysteine (Hcy) is the last intermediate on the methionine biosynthetic pathway. Supplementation of a glucose-based minimal medium with Hcy at concentrations greater than 0.2 mM causes the growth ofE. coliFrag1 to be inhibited. Supplementation of Hcy-treated cultures with combinations of branched-chain amino acids containing isoleucine or with isoleucine alone reversed the inhibitory effects of Hcy on growth. The last intermediate of the isoleucine biosynthetic pathway, α-keto-β-methylvalerate, could also alleviate the growth inhibition caused by Hcy. Analysis of amino acid pools in Hcy-treated cells revealed that alanine, valine, and glutamate levels are depleted. Isoleucine could reverse the effects of Hcy on the cytoplasmic pools of valine and alanine. Supplementation of the culture medium with alanine gave partial relief from the inhibitory effects of Hcy. Enzyme assays revealed that the first step of the isoleucine biosynthetic pathway, catalyzed by threonine deaminase, was sensitive to inhibition by Hcy. The gene encoding threonine deaminase,ilvA, was found to be transcribed at higher levels in the presence of Hcy. Overexpression of theilvAgene from a plasmid could overcome Hcy-mediated growth inhibition. Together, these data indicate that inE. coliHcy toxicity is caused by a perturbation of branched-chain amino acid biosynthesis that is caused, at least in part, by the inhibition of threonine deaminase.
DNA Binding-Uptake System: a Link between Cell-to-Cell Communication and Biofilm Formation
Authors: Petersen Fernanda C. , Tao Lin , Scheie Anne A. 
Published: June 2005

ABSTRACTDNA has recently been described as a major structural component of the extracellular matrix in biofilms. In streptococci, the competence-stimulating peptide (CSP) cell-to-cell signal is involved in competence for genetic transformation, biofilm formation, and autolysis. Among the genes regulated in response to the CSP are those involved in binding and uptake of extracellular DNA. We show in this study that a functional DNA binding-uptake system is involved in biofilm formation. AcomGBmutant ofStreptococcus mutansdeficient in DNA binding and uptake, but unaffected in signaling, showed reduced biofilm formation. During growth in the presence of DNase I, biofilm was reduced in the wild type to levels similar to those found with thecomGBmutant, suggesting that DNA plays an important role in the wild-type biofilm formation. We also showed that growth in the presence of synthetic CSP promoted significant release of DNA, with similar levels in the wild type and in thecomGBmutant. The importance of the DNA binding-uptake system in biofilm formation points to possible novel targets to fight infections.
Coupling of NAD+Biosynthesis and Nicotinamide Ribosyl Transport: Characterization of NadR Ribonucleotide Kinase Mutants ofHaemophilus influenzae
Authors: Merdanovic Melisa , Sauer Elizabeta , Reidl Joachim 
Published: June 2005

ABSTRACTPreviously, we characterized a pathway necessary for the processing of NAD+and for uptake of nicotinamide riboside (NR) inHaemophilus influenzae. Here we report on the role of NadR, which is essential for NAD+utilization in this organism. Different NadR variants with a deleted ribonucleotide kinase domain or with a single amino acid change were characterized in vitro and in vivo with respect to cell viability, ribonucleotide kinase activity, and NR transport. The ribonucleotide kinase mutants were viable only in anadV+(nicotinamide phosphoribosyltransferase) background, indicating that the ribonucleotide kinase domain is essential for cell viability inH. influenzae. Mutations located in the Walker A and B motifs and the LID region resulted in deficiencies in both NR phosphorylation and NR uptake. The ribonucleotide kinase function of NadR was found to be feedback controlled by NAD+under in vitro conditions and by NAD+utilization in vivo. Taken together, our data demonstrate that the NR phosphorylation step is essential for both NR uptake across the inner membrane and NAD+synthesis and is also involved in controlling the NAD+biosynthesis rate.
Initiation and Synthesis of the
Streptococcus pneumoniae
Type 3 Capsule on a Phosphatidylglycerol Membrane Anchor
Authors: Cartee Robert T. , Forsee W. Thomas , Yother Janet 
Published: June 2005

ABSTRACT

The type 3 synthase from
Streptococcus pneumoniae
is a processive β-glycosyltransferase that assembles the type 3 polysaccharide [3)-β-
d
-GlcUA-(1→4)-β-
d
-Glc-(1→] by a multicatalytic process. Polymer synthesis occurs via alternate additions of Glc and GlcUA onto the nonreducing end of the growing polysaccharide chain. In the presence of a single nucleotide sugar substrate, the type 3 synthase ejects its nascent polymer and also adds a single sugar onto a lipid acceptor. Following single sugar incorporation from either UDP-[
14
C]Glc or UDP-[
14
C]GlcUA, we found that phospholipase D digestion of the Glc-labeled lipid yielded a product larger than a monosaccharide, while digestion of the GlcUA-labeled lipid resulted in a product larger than a disaccharide. These data indicated that the lipid acceptor contained a headgroup and that the order of addition to the lipid acceptor was Glc followed by GlcUA. Higher-molecular-weight product synthesized in vitro was also sensitive to phospholipase D digestion, suggesting that the same lipid acceptor was being used for single sugar additions and for polymer formation. Mass spectral analysis of the anionic lipids of a type 3
S. pneumoniae
strain demonstrated the presence of glycosylated phosphatidylglycerol. This lipid was also observed in
Escherichia coli
strains expressing the recombinant type 3 synthase. The presence of the lipid primer in
S. pneumoniae
membranes explained both the ability of the synthase to reinitiate polysaccharide synthesis following ejection of its nascent chain and the association of newly synthesized polymer with the membrane. Unlike most
S. pneumoniae
capsular polysaccharides, the type 3 capsule is not covalently linked to the cell wall. The present data indicate that phosphatidylglycerol may anchor the type 3 polysaccharide to the cell membrane.
Phenylacetate Catabolism in
Rhodococcus
sp. Strain RHA1: a Central Pathway for Degradation of Aromatic Compounds
Authors: Navarro-Llorens Juana María , Patrauchan Marianna A. , Stewart Gordon R. , Davies Julian E. , Eltis Lindsay D. , Mohn William W. 
Published: June 2005

ABSTRACT

In gram-negative bacteria, a pathway for aerobic degradation of phenylacetic acid (PAA) that proceeds via phenylacetyl-coenzyme A (CoA) and hydrolytic ring fission plays a central role in the degradation of a range of aromatic compounds. In contrast, the PAA pathway and its role are not well characterized in gram-positive bacteria. A cluster including 13
paa
genes encoding enzymes orthologous to those of gram-negative bacteria was identified on the chromosome of
Rhodococcus
sp. strain RHA1. These genes were transcribed during growth on PAA, with 11 of the genes apparently in an operon yielding a single transcript. Quantitative proteomic analyses revealed that at least 146 proteins were more than twice as abundant in PAA-grown cells of RHA1 than in pyruvate-grown cells. Of these proteins, 29 were identified, including 8 encoded by the
paa
genes. Knockout mutagenesis indicated that
paaN
, encoding a putative ring-opening enzyme, was essential for growth on PAA. However,
paaF
, encoding phenylacetyl-CoA ligase, and
paaR
, encoding a putative regulator, were not essential.
paaN
was also essential for growth of RHA1 on phenylacetaldehyde, phenylpyruvate, 4-phenylbutyrate, 2-phenylethanol, 2-phenylethylamine, and
l
-phenylalanine. In contrast, growth on 3-hydroxyphenylacetate, ethylbenzene, and styrene was unaffected. These results suggest that the range of substrates degraded via the PAA pathway in RHA1 is somewhat limited relative to the range in previously characterized gram-negative bacteria.
Characterization of Six Lipoproteins in the σERegulon
Authors: Onufryk Christina , Crouch Marie-Laure , Fang Ferric C. , Gross Carol A. 
Published: June 2005

ABSTRACTInEscherichia coli, σEregulon functions are required for envelope homeostasis during stress and are essential for viability under all growth conditions. TheE. coligenome encodes approximately 100 lipoproteins, and 6 of these are regulated by σE. Phenotypes associated with deletion of each of these lipoproteins are the subject of this report. One lipoprotein, YfiO, is essential for cellular viability. However, overexpression of this protein is not sufficient to alleviate the requirement of σEfor viability, suggesting that the σEregulon provides more than one essential function. The remaining five lipoproteins in the σEregulon are nonessential; cells are viable even when all five are removed simultaneously. Deletion of three nonessential lipoprotein genes (nlpB,yraP,ygfL) results in the exhibition of phenotypes that suggest they are important for maintenance of the integrity of the cell envelope. ΔnlpBcells are selectively sensitive to rifampin; ΔyraPcells are selectively sensitive to sodium dodecyl sulfate. Such selective sensitivity has not been previously reported. Both ΔyraPand ΔnlpBare synthetically lethal withsurA::Cm, which encodes a periplasmic chaperone and PPIase, suggesting that NlpB and YraP play roles in a periplasmic folding pathway that functions in parallel with that of SurA. Finally, the ΔyfgLmutant exhibits a broad range of envelope defects, including sensitivity to several membrane-impermeable agents, an altered outer membrane protein profile, synthetic lethality with bothsurA::Cmand ΔfkpA::Cmstrains, and sensitivity to a bactericidal permeability-increasing peptide. We suggest that this lipoprotein performs a very important but as-yet-unknown function in maintaining the integrity of the cell envelope.
Two NewSinorhizobium melilotiLysR-Type Transcriptional Regulators Required for Nodulation
Authors: Luo Li , Yao Shi-Yi , Becker Anke , Rüberg Silvia , Yu Guan-Qiao , Zhu Jia-Bi , Cheng Hai-Ping 
Published: June 2005

ABSTRACTThe establishment of an effective nitrogen-fixing symbiosis betweenSinorhizobium melilotiand its legume host alfalfa (Medicago sativa) depends on the timely expression of nodulation genes that are controlled by LysR-type regulators. Ninety putative genes coding for LysR-type transcriptional regulators were identified in the recently sequencedS. melilotigenome. All 90 putativelysRgenes were mutagenized using plasmid insertions as a first step toward determining their roles in symbiosis. Two new LysR-type symbiosis regulator genes,lsrAandlsrB, were identified in the screening. Both thelsrAandlsrBgenes are expressed in free-livingS. meliloticells, but they are not required for cell growth. AnlsrA1mutant was defective in symbiosis and elicited only white nodules that exhibited no nitrogenase activity. Cells of thelsrA1mutant were recovered from the white nodules, suggesting that thelsrA1mutant was blocked early in nodulation. AnlsrB1mutant was deficient in symbiosis and elicited a mixture of pink and white nodules on alfalfa plants. These plants exhibited lower overall nitrogenase activity than plants inoculated with the wild-type strain, which is consistent with the fact that most of the alfalfa plants inoculated with thelsrB1mutant were short and yellow. Cells of thelsrB1mutant were recovered from both pink and white nodules, suggesting thatlsrB1mutants could be blocked at multiple points during nodulation. The identification of two new LysR-type symbiosis transcriptional regulators provides two new avenues for understanding the complexS. meliloti-alfalfa interactions which occur during symbiosis.