bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recombinant activated factor VII for neurological and neurosurgical bleeding emergencies
Authors: RINCON FRED , FERNANDEZ ANDRES , MAYER STEPHAN A. 
Published: November 2006

SUMMARYThe management of central nervous system bleeding emergencies is a common clinical challenge. The most common scenarios include spontaneous intracerebral hemorrhage (ICH), aneurysmal subarachnoid hemorrhage (SAH), traumatic epidural and subdural hematomas, hemorrhagic infarction and spinal epidural bleeding. A recent phase II clinical trial demonstrated that ultra‐early hemostatic therapy with recombinant activated factor VII (rFVIIa) limits ongoing bleeding, reduces hematoma volume and improves survival and functional outcome, despite a small increase in the risk of thromboembolic complications. A definitive phase III study (the FAST [rFVIIa in Acute Hemorrhagic Stroke Treatment] Trial) is now in progress to confirm these results. A pilot trial of continuous rFVIIa infusion to prevent re‐bleeding after SAH was stopped because of concerns regarding ischemic complications related to vasospasm. Intravenous vitamin K and fresh frozen plasma are the mainstays of therapy for coagulopathic intracranial bleeding, but normalization of coagulation can take many hours, and outcomes are often unsatisfactory. Successful off‐label use of rFVIIa to stabilize patients with warfarin‐associated ICH and subdural hematoma or to expedite emergency surgery has been reported, but questions remain regarding the optimal dose for this indication. Clinical trials are urgently needed to confirm that rFVIIa can safely arrest active bleeding and expedite life‐saving emergency neurosurgical procedures in anticoagulated patients with intracranial hemorrhage.
Lysostaphin-Resistant Variants of
Staphylococcus aureus
Demonstrate Reduced Fitness In Vitro and In Vivo
Authors: Kusuma Caroline , Jadanova Anna , Chanturiya Tanya , Kokai-Kun John F. 
Published: November 2006

ABSTRACT

Lysostaphin is under development as a therapy for serious staphylococcal infections. During preclinical development, lysostaphin-resistant
Staphylococcus aureus
variants have occasionally been reported in vitro and in vivo. The acquisition of resistance to this drug, however, leads to a significant increase in β-lactam antibiotic susceptibility, rendering methicillin-resistant
S. aureus
(MRSA) strains functionally methicillin susceptible. In this study, we have demonstrated that the development of lysostaphin resistance by two strains of MRSA also led to a loss of fitness in the variants. Consistent with the mutations found in previously reported lysostaphin-resistant
S. aureus
variants, these two variants had mutations in their
femA
genes, resulting in nonfunctional FemA proteins and, thus, monoglycine cross bridges in the peptidoglycan. The diminished fitness of the lysostaphin-resistant variants was reflected by (i) a reduced logarithmic growth rate, with the variants being outcompeted in cocultures by their wild-type parental strains; (ii) increased susceptibility to elevated temperatures; and (iii) at least fivefold less virulence of the lysostaphin-resistant variants than their wild-type strains in a mouse kidney infection model, with the lysostaphin-resistant variants being outcompeted in coinfections with their wild-type parental strains. During a 14-day serial passage without selective pressure, the lysostaphin-resistant variants failed to develop compensatory mutations which restored their fitness. These results suggest that should lysostaphin resistance due to an alteration in the FemA function emerge in
S. aureus
during therapy with lysostaphin, the resistant variants would be less fit and less virulent, and, in addition, infections with these strains would be easily treatable with β-lactam antibiotics.
Synthesis of Omeprazole Analogues and Evaluation of These as Potential Inhibitors of the Multidrug Efflux Pump NorA ofStaphylococcus aureus
Authors: Vidaillac Céline , Guillon Jean , Arpin Corinne , Forfar-Bares Isabelle , Ba Boubakar B. , Grellet Jean , Moreau Stéphane , Caignard Daniel-Henri , Jarry Christian , Quentin Claudine 
Published: November 2006

ABSTRACTA series of 11 pyrrolo[1,2-a]quinoxaline derivatives, 1a to 1k, sharing structural analogies with omeprazole, a eukaryotic efflux pump inhibitor (EPI) used as an antiulcer agent, was synthesized. Their inhibitory effect was evaluated usingStaphylococcus aureusstrain SA-1199B overexpressing NorA. By determinations of the MIC of norfloxacin in the presence of these EPIs devoid of intrinsic antibacterial activity and used at 128 μg/ml, and by the checkerboard method, compound 1e (MIC decrease, 16-fold; fractional inhibitory concentration index [ΣFIC], 0.18) appeared to be more active than compounds 1b to 1d, reserpine, and omeprazole (MIC decrease, eightfold; ΣFIC, 0.31), followed by compounds 1a and 1f (MIC decrease, fourfold; ΣFIC, 0.37) and 1g to 1k (MIC decrease, twofold; ΣFIC, 0.50 to 0.56). By time-kill curves combining norfloxacin (1/4 MIC) and the most efficient EPIs (128 μg/ml), compound 1e persistently restored the bactericidal activity of norfloxacin (inoculum reduction, 3 log10CFU/ml at 8 and 24 h), compound 1f led to a delayed but progressive decrease in the number of viable cells, and compounds 1b to 1d and omeprazole acted synergistically (inoculum reduction, 3 log10CFU/ml at 8 h but further regrowth), while compound 1a and reserpine slightly enhanced norfloxacin activity. The bacterial uptake of norfloxacin monitored by high-performance liquid chromatography confirmed that compounds 1a to 1f increased antibiotic accumulation, as did reserpine and omeprazole. Since these EPIs did not disturb the Δψ and ΔpH, they might directly interact with the pump. A structure-activity relationships study identified the benzimidazole nucleus of omeprazole as the main structural element involved in efflux pump inhibition and highlighted the critical role of the chlorine substituents in the stability and efficiency of compounds 1e to 1f. However, further pharmacomodulation is required to obtain therapeutically applicable derivatives.
Microarray-Based Analysis of Microbial Community RNAs by Whole-Community RNA Amplification
Authors: Gao Haichun , Yang Zamin K. , Gentry Terry J. , Wu Liyou , Schadt Christopher W. , Zhou Jizhong 
Published: November 2006

ABSTRACT

A new approach, termed whole-community RNA amplification (WCRA), was developed to provide sufficient amounts of mRNAs from environmental samples for microarray analysis. This method employs fusion primers (six to nine random nucleotides with an attached T7 promoter) for the first-strand synthesis. The shortest primer (T7N6S) gave the best results in terms of the yield and representativeness of amplification. About 1,200- to 1,800-fold amplification was obtained with amounts of the RNA templates ranging from 10 to 100 ng, and very representative detection was obtained with 50 to 100 ng total RNA. Evaluation with a
Shewanella oneidensis
Δ
fur
strain revealed that the amplification method which we developed could preserve the original abundance relationships of mRNAs. In addition, to determine whether representative detection of RNAs can be achieved with mixed community samples, amplification biases were evaluated with a mixture containing equal quantities of RNAs (100 ng each) from four bacterial species, and representative amplification was also obtained. Finally, the method which we developed was applied to the active microbial populations in a denitrifying fluidized bed reactor used for denitrification of contaminated groundwater and ethanol-stimulated groundwater samples for uranium reduction. The genes expressed were consistent with the expected functions of the bioreactor and groundwater system, suggesting that this approach is useful for analyzing the functional activities of microbial communities. This is one of the first demonstrations that microarray-based technology can be used to successfully detect the activities of microbial communities from real environmental samples in a high-throughput fashion.
The Single Extracytoplasmic-Function Sigma Factor of
Xylella fastidiosa
Is Involved in the Heat Shock Response and Presents an Unusual Regulatory Mechanism
Authors: da Silva Neto José F. , Koide Tie , Gomes Suely L. , Marques Marilis V. 
Published: November 2006

ABSTRACT

Genome sequence analysis of the bacterium
Xylella fastidiosa
revealed the presence of two genes, named
rpoE
and
rseA
, predicted to encode an
e
xtra
c
ytoplasmic
f
unction (ECF) sigma factor and an anti-sigma factor, respectively. In this work, an
rpoE
null mutant was constructed in the citrus strain J1a12 and shown to be sensitive to exposure to heat shock and ethanol. To identify the
X. fastidiosa
σ
E
regulon, global gene expression profiles were obtained by DNA microarray analysis of bacterial cells under heat shock, identifying 21 σ
E
-dependent genes. These genes encode proteins belonging to different functional categories, such as enzymes involved in protein folding and degradation, signal transduction, and DNA restriction modification and hypothetical proteins. Several putative σ
E
-dependent promoters were mapped by primer extension, and alignment of the mapped promoters revealed a consensus sequence similar to those of ECF sigma factor promoters of other bacteria. Like other ECF sigma factors,
rpoE
and
rseA
were shown to comprise an operon in
X. fastidiosa
, together with a third open reading frame (XF2241). However, upon heat shock,
rpoE
expression was not induced, while
rseA
and XF2241 were highly induced at a newly identified σ
E
-dependent promoter internal to the operon. Therefore, unlike many other ECF sigma factors,
rpoE
is not autoregulated but instead positively regulates the gene encoding its putative anti-sigma factor.
Helicobacter pylori
VacA Toxin Inhibits Human Immunodeficiency Virus Infection of Primary Human T Cells
Authors: Oswald-Richter Kyra , Torres Victor J. , Sundrud Mark S. , VanCompernolle Scott E. , Cover Timothy L. , Unutmaz Derya 
Published: November 2006

ABSTRACT

Human CD4
+
T cells are major targets for human immunodeficiency virus (HIV) infection. Resting T cells are resistant to HIV infection unless activated through the T-cell receptor (TCR) or by cytokine signals. How T-cell signaling promotes susceptibility of T cells to HIV infection remains poorly understood. Here we demonstrate that the VacA toxin produced by
Helicobacter pylori
can inhibit HIV infection of primary T cells, stimulated through the TCR or by cytokines alone. This activity of VacA was dependent on its ability to form membrane channels. VacA suppressed HIV infection of T cells at a stage after viral entry, post-reverse transcription and pre-two-long-terminal-repeat circle formation, similar to the cytokine signaling inhibitor rapamycin. Mechanistically, neither VacA nor rapamycin inhibited the activation of cytokine signal transduction components (STAT5, p42/44 mitogen-activated protein kinase, or p38), but both blocked activation of key regulatory proteins required for G
1
cell cycle transition. In contrast to rapamycin, VacA did not suppress phosphorylation of p70 S6 kinase but caused mitochondrial depolarization and ATP depletion within primary T cells. These results suggest that VacA inhibits T-cell activation and HIV infection via a novel mechanism. Identifying the host cell targets of VacA could be useful for elucidating the HIV life cycle within primary T cells.
Diminished Production of Monocyte Proinflammatory Cytokines during Human Immunodeficiency Virus Viremia Is Mediated by Type I Interferons
Authors: Tilton John C. , Johnson Alison J. , Luskin Marlise R. , Manion Maura M. , Yang Jun , Adelsberger Joseph W. , Lempicki Richard A. , Hallahan Claire W. , McLaughlin Mary , Mican JoAnn M. , Metcalf Julia A. , Iyasere Christiana , Connors Mark 
Published: November 2006

ABSTRACTThe effect of human immunodeficiency virus (HIV) infection and high-level HIV replication on the function of monocytes was investigated. HIV-positive patients had elevated levels of spontaneous production of some or all of the monocyte proinflammatory cytokines measured (interleukin-1β [IL-1β], IL-6, and tumor necrosis factor alpha [TNF-α]) compared to uninfected controls. In patients on therapy with high frequencies of monocytes producing proinflammatory cytokines, this frequency was diminished in the context of viremia during an interruption of therapy. Diminished production of proinflammatory cytokines during viremia was restored by culture with autologous CD4+T cells or monocytes from an on-therapy time point or lipopolysaccharide (LPS). Microarray analysis demonstrated that diminished monocyte production of proinflammatory cytokines was correlated with elevated type I interferon-stimulated gene transcripts. The addition of exogenous alpha 2A interferon diminished the spontaneous production of IL-1β, IL-6, and TNF-α but did not affect responses to LPS, recapitulating the changes observed for HIV-viremic patients. These results suggest that monocyte function is diminished during high-level HIV viremia and that this effect is mediated by chronic stimulation by type I interferons. This effect on monocytes during viremia may play a role in diminished innate or adaptive immune system functions in HIV-infected patients. In addition, the restoration of these functions may also play a role in some immune reconstitution syndromes observed during initiation of therapy.
ORF66 Protein Kinase Function Is Required for T-Cell Tropism of Varicella-Zoster Virus In Vivo
Authors: Schaap-Nutt Anne , Sommer Marvin , Che Xibing , Zerboni Leigh , Arvin Ann M. 
Published: November 2006

ABSTRACT
Several functions have been attributed to the serine/threonine protein kinase encoded by open reading frame 66 (ORF66) of varicella-zoster virus (VZV), including modulation of the apoptosis and interferon pathways, down-regulation of major histocompatibility complex class I cell surface expression, and regulation of IE62 localization. The amino acid sequence of the ORF66 protein contains a recognizable conserved kinase domain. Point mutations were introduced into conserved protein kinase motifs to evaluate their importance to ORF66 protein functions. Two substitution mutants were generated, including a G102A substitution, which blocked autophosphorylation and altered IE62 localization, and an S250P substitution, which had no effect on either autophosphorylation or IE62 localization. Both kinase domain mutants grew to titers equivalent to recombinant parent Oka (pOka) in vitro. pOka66G102A had slightly reduced growth in skin, which was comparable to the reduction observed when ORF66 translation was prevented by stop codon insertions in pOka66S. In contrast, infection of T-cell xenografts with pOka66G102A was associated with a significant decrease in infectious virus production equivalent to the impaired T-cell tropism found with pOka66S infection of T-cell xenografts in vivo. Disrupting kinase activity with the G102A mutation did not alter IE62 cytoplasmic localization in VZV-infected T cells, suggesting that decreased T-cell tropism is due to other ORF66 protein functions. The G102A mutation reduced the antiapoptotic effects of VZV infection of T cells. These experiments indicate that the T-cell tropism of VZV depends upon intact ORF66 protein kinase function.
The Hepatitis C Virus RNA 3′-Untranslated Region Strongly Enhances Translation Directed by the Internal Ribosome Entry Site
Authors: Song Yutong , Friebe Peter , Tzima Eleni , Jünemann Christiane , Bartenschlager Ralf , Niepmann Michael 
Published: November 2006

ABSTRACT
The positive-strand RNA genome of the hepatitis C virus (HCV) is flanked by 5′- and 3′-untranslated regions (UTRs). Translation of the viral RNA is directed by the internal ribosome entry site (IRES) in the 5′-UTR, and subsequent viral RNA replication requires sequences in the 3′-UTR and in the 5′-UTR. Addressing previous conflicting reports on a possible function of the 3′-UTR for RNA translation in this study, we found that reporter construct design is an important parameter in experiments testing 3′-UTR function. A translation enhancer function of the HCV 3′-UTR was detected only after transfection of monocistronic reporter RNAs or complete RNA genomes having a 3′-UTR with a precise 3′ terminus. The 3′-UTR strongly stimulates HCV IRES-dependent translation in human hepatoma cell lines but only weakly in nonliver cell lines. The variable region, the poly(U · C) tract, and the most 3′ terminal stem-loop 1 of the highly conserved 3′ X region contribute significantly to translation enhancement, whereas stem-loops 2 and 3 of the 3′ X region are involved only to a minor extent. Thus, the signals for translation enhancement and for the initiation of RNA minus-strand synthesis in the HCV 3′-UTR partially overlap, supporting the idea that these sequences along with viral and possibly also cellular factors may be involved in an RNA 3′-5′ end interaction and a switch between translation and RNA replication.
Overexpression of the Lens Epithelium-Derived Growth Factor/p75 Integrase Binding Domain Inhibits Human Immunodeficiency Virus Replication
Authors: De Rijck Jan , Vandekerckhove Linos , Gijsbers Rik , Hombrouck Anneleen , Hendrix Jelle , Vercammen Jo , Engelborghs Yves , Christ Frauke , Debyser Zeger 
Published: November 2006

ABSTRACT
We initially identified lens epithelium-derived growth factor/p75 (LEDGF/p75) as a binding partner of human immunodeficiency virus type 1 (HIV-1) integrase. To investigate the role of LEDGF/p75 in HIV replication and its potential as a new antiviral target, we stably overexpressed two different fragments containing the integrase binding domain (IBD) of LEDGF/p75 fused to enhanced green fluorescent protein (eGFP). HIV-1 replication was severely inhibited by overexpression of the eGFP-IBD fusion proteins, while no inhibition was observed in cell lines overexpressing the interaction-deficient D366A mutant. Quantitative PCR pinpointed the block to the integration step, whereas nuclear import was not affected. Competition of the IBD fusion proteins with endogenous LEDGF/p75 for binding to integrase led to a potent defect in HIV-1 replication in both HeLaP4- and MT-4-derived cell lines. A previously described diketo acid-resistant HIV-1 strain remained fully susceptible to inhibition, suggesting that this strategy will also work in patients who harbor strains resistant to the current experimental integrase inhibitors. These data support LEDGF/p75 as an important cofactor for HIV replication and provide proof of concept for the LEDGF/p75-integrase interaction as a novel target for treating HIV-1 infection.
Novel Fiber-Dependent Entry Mechanism for Adenovirus Serotype 5 in LacrimalAcini
Authors: Xie Jiansong , Chiang Lilian , Contreras Janette , Wu Kaijin , Garner Judy A. , Medina-Kauwe Lali , Hamm-Alvarez Sarah F. 
Published: November 2006

ABSTRACT

The established mechanism for infection of most cells with adenovirus serotype 5 (Ad5) involves fiber capsid protein binding to
coxsackievirus-adenovirus receptor (CAR) at the cell surface, followed by penton base capsid protein binding to α
v
integrins, which triggers clathrin-mediated endocytosis of the virus. Here we determined the identity of the capsid proteins responsible for
mediating Ad5 entry into the acinar epithelial cells of the lacrimal gland. Ad5 transduction of primary rabbit lacrimal acinar cells was
inhibited by excess Ad5 fiber or knob (terminal region of the fiber) but not excess penton base. Investigation of the interactions of
recombinant Ad5 penton base, fiber, and knob with lacrimal acini revealed that the penton base capsid protein remained surface
associated, while the knob domain of the fiber capsid protein was rapidly internalized. Introduction of rabbit CAR-specific small
interfering RNA (siRNA) into lacrimal acini under conditions that reduced intracellular CAR mRNA significantly inhibited Ad5
transduction, in contrast to a control (nonspecific) siRNA. Preincubation of Ad5 with excess heparin or pretreatment of acini with
a heparinase cocktail each inhibited Ad5 transduction by a separate and apparently additive mechanism. Functional and imaging studies revealed
that Ad5, fiber, and knob, but not penton base, stimulated macropinocytosis in acini and that inhibition of macropinocytosis
significantly reduced Ad5 transduction of acini. However, inhibition of macropinocytosis did not reduce Ad5 uptake. We propose that
internalization of Ad5 into lacrimal acini is through a novel fiber-dependent mechanism that includes CAR and heparan sulfate
glycosaminoglycans and that the subsequent intracellular trafficking of Ad5 is enhanced by fiber-induced macropinocytosis.
Flavivirus Infection Activates the XBP1 Pathway of the Unfolded Protein Response To Cope with Endoplasmic Reticulum Stress
Authors: Yu Chia-Yi , Hsu Yun-Wei , Liao Ching-Len , Lin Yi-Ling 
Published: November 2006

ABSTRACT

The unfolded protein response (UPR) is a coordinated change in gene expression triggered by perturbations in functions of the endoplasmic reticulum (ER). XBP1, a key transcription factor of the UPR, is activated by an IRE1-mediated splicing event, which results in a frameshift and encodes a protein with transcriptional activity. Here, we report that XBP1 was activated during flaviviral infection, as evidenced by
XBP1
mRNA splicing and protein expression, as well as induction of the downstream genes
ERdj4
,
EDEM1
, and
p58(IPK)
in Japanese encephalitis virus (JEV)- and dengue virus serotype 2 (DEN-2)-infected cells. Reporter systems based on IRE1-mediated
XBP1
splicing were established, and several flaviviral proteins associated with the ER, including glycoproteins and small hydrophobic membrane-anchored proteins, were found to trigger the splicing event. Notably, nonstructural protein NS2B-3 of DEN-2, but not of JEV, was a potent inducer of
XBP1
splicing through an unclear mechanism(s). Reduction of XBP1 by a small interfering RNA had no effect on cells' susceptibility to the two viruses but exacerbated the flavivirus-induced cytopathic effects. Overall, flaviviruses trigger the XBP1 signaling pathway and take advantage of this cellular response to alleviate virus-induced cytotoxicity.
Inhibition of Coxsackievirus B3 in Cell Cultures and in Mice by Peptide-Conjugated Morpholino Oligomers Targeting the Internal Ribosome Entry Site
Authors: Yuan Ji , Stein David A. , Lim Travis , Qiu Dexin , Coughlin Shaun , Liu Zhen , Wang Yinjing , Blouch Robert , Moulton Hong M. , Iversen Patrick L. , Yang Decheng 
Published: November 2006

ABSTRACT

Coxsackievirus B3 (CVB3) is a primary cause of viral myocarditis, yet no effective therapeutic against CVB3 is available. Nucleic acid-based interventional strategies against various viruses, including CVB3, have shown promise experimentally, but limited stability and inefficient delivery in vivo remain as obstacles to their potential as therapeutics. We employed phosphorodiamidate morpholino oligomers (PMO) conjugated to a cell-penetrating arginine-rich peptide, P007 (to form PPMO), to address these issues. Eight CVB3-specific PPMO were evaluated with HeLa cells and HL-1 cardiomyocytes in culture and in a murine infection model. One of the PPMO (PPMO-6), designed to target a sequence in the 3′ portion of the CVB3 internal ribosomal entry site, was found to be especially potent against CVB3. Treatment of cells with PPMO-6 prior to CVB3 infection produced an approximately 3-log
10
decrease in viral titer and largely protected cells from a virus-induced cytopathic effect. A similar antiviral effect was observed when PPMO-6 treatment began shortly after the virus infection period. A/J mice receiving intravenous administration of PPMO-6 once prior to and once after CVB3 infection showed an ∼2-log
10
-decreased viral titer in the myocardium at 7 days postinfection and a significantly decreased level of cardiac tissue damage, compared to the controls. Thus, PPMO-6 provided potent inhibition of CVB3 amplification both in cell cultures and in vivo and appears worthy of further evaluation as a candidate for clinical development.