bluuebunny/crossref_metadata_2025_split huggingface dataset:
Progressive oxidation of cytoskeletal proteins and accumulation of denatured hemoglobin in stored red cells
Authors: Kriebardis Anastasios G. , Antonelou Marianna H. , Stamoulis Konstantinos E. , Economou‐Petersen Effrosini , Margaritis Lukas H. , Papassideri Issidora S. 
Published: March 2007

AbstractRed blood cell (RBC) membrane proteins undergo progressive pathological alterations during storage. In conditions of increased cellular stress, the cytoskeleton also sustains certain modifications. The hemoglobin (Hb) content and oxidative status of the RBC cytoskeletons as a function of the storage period remain unclear. The possible Hb content and oxidative alterations occurring in the cytoskeletons in the course of storage were monitored in six units, by means of electrophoresis, immunoblotting and protein carbonylation assays. A proportion of the ghost‐bound Hb consists of non‐reducible crosslinkings of probably oxidized(denatured Hb or hemichromes.The defective Hb‐membrane association was strongly affected by the prolonged storage. A progressive accumulation of Hb monomers, multimers and high molecular weight aggregates to corresponding cytoskeletons were also evident. The oxidative index of the cytoskeletal proteins was found increased, signalizing oxidative modifications in spectrin and possibly other cytoskeletal proteins. The reported data corroborate the evidence for oxidative damage in membrane proteins with emphasis to the cytoskeletal components. They partially address the pathophysiological mechanisms underlying the RBC storage lesion, add some new insight in the field of RBC storage as a hemoglobin‐ and cytoskeleton‐associated pathology and suggest the possible use of antioxidants in the units intended for transfusion.
Effects of Thalidomide on Isoprenaline‐Induced Acute Myocardial Injury: A Haemodynamic, Histopathological and Ultrastructural Study
Authors: Loh Harish K. , Sahoo Kanhei C. , Kishore Kamal , Ray Ruma , Nag Tapas C. , Kumari Santosh , Arya Dharamvir S. 
Published: March 2007

Abstract:  In the present study, we investigated the cardioprotective effects of thalidomide in a rat model of acute myocardial injury, induced by subcutaneous injection of isoprenaline hemisulphate (85 mg/kg per day for 2 days). Thalidomide (75/150/300 mg/kg) or vehicle (dimethylsulphoxide) or saline (0.9% NaCl) was administered orally for 14 days and isoprenaline injection on the 12th and 13th days. Cardiovascular responses (arterial and left ventricular haemodynamic parameters and heart rate) were obtained in anaesthetized rats on the 14th day. Histopathological and electronmicroscopical analysis of myocardial injury was done. The results showed that thalidomide 300 mg/kg per day orally caused significant improvement in isoprenaline‐induced reduction of cardiac function with increases in maximum rate of pressure development (+LVdP/dt, P < 0.001) and maximum rate of pressure decline (–LVdP/dt, P < 0.001) and decreases in left ventricular end‐diastolic pressure (P < 0.01), systolic arterial pressure (P < 0.001), diastolic arterial pressure (P < 0.001), mean arterial pressure (P < 0.001) and heart rate (P < 0.001). The myocardial injury caused by isoprenaline was significantly reduced by thalidomide treatment as judged by the reduction of myocardial necrosis, ultrastructural changes such as mitochondria and myofibril damage, 300 mg/kg being the most effective dose. In conclusion, oral administration of thalidomide is able to ameliorate isoprenaline‐induced myocardial injury and impaired myocardial function in spite of decreases in systolic arterial pressure, diastolic arterial pressure and mean arterial pressure, which may be due to its depressant effect on the sino‐atrial node and sedative action.
Stream Temperature Surges Under Urbanization and Climate Change: Data, Models, and Responses1
Authors: Nelson Kären C. , Palmer Margaret A. 
Published: March 2007

ABSTRACT: Multiple anthropogenic stressors, including increased watershed imperviousness, destruction of the riparian vegetation, increased siltation, and changes in climate, will impact streams over the coming century. These stressors will alter water temperature, thus influencing ecological processes and stream biota. Quantitative tools are needed to predict the magnitude and direction of altered thermal regimes. Here, empirical relationships were derived to complement a simple model of in‐stream temperature [developed by Caissie et al. Canadian Journal of Civil Engineering25 (1998) 250; Journal of Hydrology251 (2001) 14], including seasonal temperature shifts linked to land use, and temperature surges linked to localized rainstorms; surges in temperature averaged about 3.5°C and dissipated over about 3 h. These temperature surges occurred frequently at the most urbanized sites (up to 10% of summer days) and could briefly increase maximum temperature by >7°C. The combination of empirical relationships and model show that headwater streams may be more pervasively impacted by urbanization than by climate change, although the two stressors reinforce each other. A profound community shift, from common cold and coolwater species to some of the many warmwater species currently present in smaller numbers, may be expected, as shown by a count of days on which temperature exceeds the “good growth” range for coldwater species.
Protective Meningococcal Capsular Polysaccharide Epitopes and the Role of O Acetylation
Authors: Fusco Peter C. , Farley Esmé K. , Huang Chun-Hsien , Moore Samuel , Michon Francis 
Published: March 2007

ABSTRACTPrevious studies with group C meningococcal polysaccharide-tetanus toxoid (GCMP-TT) conjugates had suggested that the GCMPO-acetyl group masked the protective epitope for group C meningococci through steric hindrance or altered conformations. For this report, we confirmed this phenomenon and performed comparative studies with group Y meningococcal polysaccharide (GYMP)-TT to determine whether it might extend to other serogroups. The de-O-acetylated (dOA) polysaccharides (PSs) resulted in higher serum bactericidal activities (SBA) towards the O-acetylated (OA) meningococcal strains from the respective serogroups. High-resolution H-nuclear magnetic resonance spectroscopy at 500 MHz and competitive inhibition serum bactericidal assays were used to characterize the nature of the protective epitope. In head-to-head comparisons with OA PSs as SBA inhibitors, the dOA PSs provided 10 to 1,000 times better inhibition for GCMP in human and mouse antisera and 6 to 13 times better inhibition for GYMP in mouse antisera, using OA strains in all assays. In addition, the SBA for OA strains was highly correlated with dOA PS-specific immunoglobulin G (r= 0.72 to 0.98) for both GCMP and GYMP. The results suggest that there may be a generalized role for theO-acetyl group to provide an epitope of misdirected immunogenicity for meningococcal PS capsules, enabling escape from immune surveillance. In addition to greater chemical consistency, the dOA forms of GCMP and GYMP conjugate vaccines endow greater immunologic competence to the PSs, rendering them capable of eliciting higher levels of functional antibodies toward the protective epitopes.
Neisseria
Species Identification Assay for the Confirmation of
Neisseria gonorrhoeae
-Positive Results of the COBAS Amplicor PCR
Authors: Mangold Kathy A. , Regner MaryAnn , Tajuddin Mohammed , Tajuddin Aamair M. , Jennings Lawrence , Du Hongyan , Kaul Karen L. 
Published: March 2007

ABSTRACT

Screening assays for
Neisseria gonorrhoeae
exhibit low positive predictive values, particularly in low-prevalence populations. A new real-time PCR assay that detects and identifies individual
Neisseria
spp. using melt curve analysis was compared to two previously published supplementary assays. NsppID, a 16S rRNA real-time PCR/melt curve assay developed to distinguish
N. gonorrhoeae
from other
Neisseria
spp., was compared to real-time PCR assays targeting genes reportedly specific for
N. gonorrhoeae
, the
cppB
gene and the
porA
pseudogene. A total of 408 clinical specimens (324 female endocervical swabs and 84 male urine or urogenital swab specimens) were screened using the COBAS Amplicor assay for
Chlamydia trachomatis
and
N. gonorrhoeae
(CT/NG) (Roche Diagnostics, Indianapolis, IN) followed by confirmatory testing via real-time PCR. The NsppID assay detected
Neisseria
spp. in 150/181 COBAS-positive specimens (82%), including six dual infections, and identified
N. gonorrhoeae
in 102 (56%) specimens. Sixty-nine of 181 (38%) specimens were positive for
N. gonorrhoeae
by
porA
pseudogene, and 115/181 (64%) were positive for
cppB
. However,
cppB
was also positive in 15% of COBAS-negative specimens, more than either NsppID (4%) or
porA
pseudogene (2%) assays. The
porA
pseudogene assay had the highest specificity for both genders but the lowest sensitivity, especially in female specimens. NsppID had a slightly lower specificity but greater sensitivity and overall accuracy. The least desirable confirmatory assay was
cppB
, due to poor specificity. The NsppID assay is an accurate confirmatory assay for
N. gonorrhoeae
detection. In addition, the NsppID assay can identify the non-
N. gonorrhoeae
species responsible for the majority of false-positive results from the COBAS Amplicor CT/NG assay.
Epstein-Barr Virus (EBV)-Infected Monocytes Facilitate Dissemination of EBV within the Oral Mucosal Epithelium
Authors: Tugizov Sharof , Herrera Rossana , Veluppillai Piri , Greenspan John , Greenspan Deborah , Palefsky Joel M. 
Published: March 2007

ABSTRACTEpstein-Barr virus (EBV) causes hairy leukoplakia (HL), a benign lesion of oral epithelium that occurs primarily in the setting of human immunodeficiency virus (HIV)-associated immunodeficiency. However, the mechanisms of EBV infection of oral epithelium are poorly understood. Analysis of HL tissues shows a small number of EBV-positive intraepithelial macrophages and dendritic/Langerhans cells. To investigate a role for these cells in spreading EBV to epithelial cells, we used tongue and buccal explants infected ex vivo with EBV. We showed that EBV first infects submucosal CD14+monocytes, which then migrate into the epithelium and spread virus to oral epithelial cells, initiating productive viral infection within the terminally differentiated spinosum and granulosum layers. Incubation of EBV-infected monocytes and oral explants with antibodies to CCR2 receptor and monocyte chemotactic protein 1 prevented entry of monocytes into the epithelium and inhibited EBV infection of keratinocytes. B lymphocytes played little part in the spread of EBV to keratinocytes in our explant model. However, cocultivation of EBV-infected B lymphocytes with uninfected monocytes in vitro showed that EBV may spread from B lymphocytes to monocytes. Circulating EBV-positive monocytes were detected in most HIV-infected individuals, consistent with a model in which EBV may be spread from B lymphocytes to monocytes, which then enter the epithelium and initiate productive viral infection of keratinocytes.
Development of a Cell-Based Assay Probing the Specific Interaction between the Human Immunodeficiency Virus Type 1 Nucleocapsid and Psi RNA In Vivo
Authors: Jang Soo In , Kim Young Ho , Paik Soon Young , You Ji Chang 
Published: March 2007

ABSTRACT
Here, we describe a cell-based in vivo assay that probes the specific interaction between nucleocapsid (NC) protein and Psi (Ψ) RNA, the human immunodeficiency virus (HIV) packaging signal. The results demonstrate for the first time a specific NC-Ψ interaction within living cells. The specificity and applicability of the assay were confirmed by mutational studies of NC and deletion-mapping analyses of Ψ-RNA as well as by testing the in vivo NC-binding effects of NC-aptamer RNAs identified previously in vitro. This assay system would facilitate further detailed studies of the NC-Ψ interaction in vivo and the screening of various anti-HIV molecules targeting NC and the specific interaction.
Importance of Calcium-Binding Site 2 in Simian Virus 40 Infection
Authors: Li Peggy P. , Nguyen Albert P. , Qu Qiumin , Jafri Qumber H. , Aungsumart Saharat , Cheng R. Holland , Kasamatsu Harumi 
Published: March 2007

ABSTRACT
The exposure of molecular signals for simian virus 40 (SV40) cell entry and nuclear entry has been postulated to involve calcium coordination at two sites on the capsid made of Vp1. The role of calcium-binding site 2 in SV40 infection was examined by analyzing four single mutants of site 2, the Glu160Lys, Glu160Arg, Glu157Lys (E157K), and Glu157Arg mutants, and an E157K-E330K combination mutant. The last three mutants were nonviable. All mutants replicated viral DNA normally, and all except the last two produced particles containing all three capsid proteins and viral DNA. The defect of the site 1-site 2 E157K-E330K double mutant implies that at least one of the sites is required for particle assembly in vivo. The nonviable E157K particles, about 10% larger in diameter than the wild type, were able to enter cells but did not lead to T-antigen expression. Cell-internalized E157K DNA effectively coimmunoprecipitated with anti-Vp1 antibody, but little of the DNA did so with anti-Vp3 antibody, and none was detected in anti-importin immunoprecipitate. Yet, a substantial amount of Vp3 was present in anti-Vp1 immune complexes, suggesting that internalized E157K particles are ineffective at exposing Vp3. Our data show that E157K mutant infection is blocked at a stage prior to the interaction of the Vp3 nuclear localization signal with importins, consistent with a role for calcium-binding site 2 in postentry steps leading to the nuclear import of the infecting SV40.
Functional Characterization of the Major and Minor Phosphorylation Sites of the P Protein of Borna Disease Virus
Authors: Schmid Sonja , Mayer Daniel , Schneider Urs , Schwemmle Martin 
Published: March 2007

ABSTRACT
The phosphoprotein P of Borna disease virus (BDV) is an essential cofactor of the viral RNA-dependent RNA polymerase. It is preferentially phosphorylated at serine residues 26 and 28 by protein kinase C ε (PKCε) and, to a lesser extent, at serine residues 70 and 86 by casein kinase II (CKII). To determine whether P phosphorylation is required for viral polymerase activity, we generated P mutants lacking either the PKCε or the CKII phosphate acceptor sites by replacing the corresponding serine residues with alanine (A). Alternatively, these sites were replaced by aspartic acid (D) to mimic phosphorylation. Functional characterization of the various mutants in the BDV minireplicon assay revealed that D substitutions at the CKII sites inhibited the polymerase-supporting activity of P, while A substitutions maintained wild-type activity. Likewise, D substitutions at the PKC sites did not impair the cofactor function of BDV-P, whereas A substitutions at these sites led to increased activity. Interestingly, recombinant viruses could be rescued only when P mutants with modified PKCε sites were used but not when both CKII sites were altered. PKCε mutant viruses showed a reduced capacity to spread in cell culture, while viral RNA and protein expression levels in persistently infected cells were almost normal. Further mutational analyses revealed that substitutions at individual CKII sites were, with the exception of a substitution of A for S86, detrimental for viral rescue. These data demonstrate that, in contrast to other viral P proteins, the cofactor activity of BDV-P is negatively regulated by phosphorylation.
Characterization of Human Immunodeficiency Virus Type 1 Monomeric and Trimeric gp120 Glycoproteins Stabilized in the CD4-Bound State: Antigenicity, Biophysics, and Immunogenicity
Authors: Dey Barna , Pancera Marie , Svehla Krisha , Shu Yuuei , Xiang Shi-Hua , Vainshtein Jeffrey , Li Yuxing , Sodroski Joseph , Kwong Peter D. , Mascola John R. , Wyatt Richard 
Published: March 2007

ABSTRACTThe human immunodeficiency virus type 1 exterior gp120 envelope glycoprotein is highly flexible, and this flexibility may contribute to the inability of monomeric gp120 immunogens to elicit broadly neutralizing antibodies. We previously showed that an S375W modification of a critical interfacial cavity central to the primary receptor binding site, the Phe43 cavity, stabilizes gp120 into the CD4-bound state. However, the immunological effects of this cavity-altering replacement were never tested. Subsequently, we screened other mutations that, along with the S375W alteration, might further stabilize the CD4-bound state. Here, we define a selected second cavity-altering replacement, T257S, and analyze the double mutations in several gp120 envelope glycoprotein contexts. The gp120 glycoproteins with the T257S-plus-S375W double mutation (T257S+S375W) have a superior antigenic profile compared to the originally identified single S375W replacement in terms of enhanced recognition by the broadly neutralizing CD4 binding-site antibody b12. Isothermal titration calorimetry measuring the entropy of the gp120 interaction with CD4 indicated that the double mutant was also stabilized into the CD4-bound state, with increasing relative fixation between core, full-length monomeric, and full-length trimeric versions of gp120. A significant increase in gp120 affinity for CD4 was also observed for the cavity-filling mutants relative to wild-type gp120. The most conformationally constrained T257S+S375W trimeric gp120 proteins were selected for immunogenicity analysis in rabbits and displayed a trend of improvement relative to their wild-type counterparts in terms of eliciting neutralizing antibodies. Together, the results suggest that conformational stabilization may improve the ability of gp120 to elicit neutralizing antibodies.
THE MASTER EQUATIONS IN THE EUCLIDEAN SCHWARZSCHILD–TANGHERLINI METRIC OF A SMALL STATIC PERTURBATION
Authors: MARTÍNEZ-MORALES JOSÉ L. 
Published: March 2007

The master equations in the Euclidean Schwarzschild–Tangherlini space–time of a small static perturbation are studied. For each harmonic mode on the sphere there are two solutions that behave differently at infinity. One solution goes like the power 2-l-n of the radial variable, the other solution goes like the power l. These solutions occur in power series. The second main statement of the paper is that any eigentensor of the Lichnerowicz operator in a Euclidean Schwarzschild space–time with an eigenvalue different from zero is essentially singular at infinity. Possible applications of the stability of instantons are discussed. We present the analysis of a small static perturbation of the Euclidean Schwarzschild–Tangherlini metric tensor. The higher order perturbations will appear later. We determine independently the static perturbations of the Schwarzschild quantum black hole in dimension 1+n≥4, where the system of equations is reduced to master equations — ordinary differential equations. The solutions are hypergeometric functions which in some cases can be reduced to polynomials. In the same Schwarzschild background, we analyze static perturbations of the scalar mode and show that there does not exist any static perturbation that is regular everywhere outside the event horizon and is well-behaved at the spatial infinity. This confirms the uniqueness of the spherically symmetric static empty quantum black hole, within the perturbation framework. Our strategy for treating the stability problem is also applicable to other symmetric quantum black holes with a nonzero cosmological constant.
Direct Visualization of Macrophage-Assisted Tumor Cell Intravasation in Mammary Tumors
Authors: Wyckoff Jeffrey B. , Wang Yarong , Lin Elaine Y. , Li Jiu-feng , Goswami Sumanta , Stanley E. Richard , Segall Jeffrey E. , Pollard Jeffrey W. , Condeelis John 
Published: March 2007

Abstract
Although the presence of macrophages in tumors has been correlated with poor prognosis, until now there was no direct observation of how macrophages are involved in hematogenous metastasis. In this study, we use multiphoton microscopy to show, for the first time, that tumor cell intravasation occurs in association with perivascular macrophages in mammary tumors. Furthermore, we show that perivascular macrophages of the mammary tumor are associated with tumor cell intravasation in the absence of local angiogenesis. These results show that the interaction between macrophages and tumor cells lying in close proximity defines a microenvironment that is directly involved in the intravasation of cancer cells in mammary tumors. [Cancer Res 2007;67(6):2649–56]
Activation of Tumor-Specific Splice Variant Rac1b by Dishevelled Promotes Canonical Wnt Signaling and Decreased Adhesion of Colorectal Cancer Cells
Authors: Esufali Susmita , Charames George S. , Pethe Vaijayanti V. , Buongiorno Pinella , Bapat Bharati 
Published: March 2007

Abstract
Rac1b is a tumor-specific splice variant of the Rac1 GTPase that displays limited functional similarities to Rac1. We have shown previously a novel cross-talk between Rac1 and β-catenin, which induces canonical Wnt pathway activation in colorectal cancer cells. This prompted us to investigate if Rac1b, frequently overexpressed in colon tumors, contributes to Wnt pathway dysregulation. We show that Rac1b overexpression stimulates Tcf-mediated gene transcription, whereas depletion of Rac1b results in decreased expression of the Wnt target gene cyclin D1. Reconstitution experiments revealed an important difference between Rac1 and Rac1b such that Rac1b was capable of functionally interacting with Dishevelled-3 (Dvl-3) but not β-catenin to mediate synergistic induction of Wnt target genes. In agreement, Dvl-3 but not β-catenin caused increased activation of Rac1b levels, which may explain the functional cooperativity displayed in transcription assays. Furthermore, we show that Rac1b negatively regulates E-cadherin expression and results in decreased adhesion of colorectal cancer cells. RNA interference–mediated suppression of Rac1b resulted in reduced expression of Slug, a specific transcriptional repressor of E-cadherin, and a concomitant increase in E-cadherin transcript levels was observed. Intriguingly, mutation of the polybasic region of Rac1b resulted in complete loss of Rac1b stimulatory effects on transcription and suppressive effects on adhesion, indicating the importance of nuclear and membrane localization of Rac1b. Our results suggest that Rac1b overexpression may facilitate tumor progression by enhancing Dvl-3–mediated Wnt pathway signaling and induction of Wnt target genes specifically involved in decreasing the adhesive properties of colorectal cancer cells. [Cancer Res 2007;67(6):2469–79]
Fine Mapping and Candidate Gene Analyses of Pulmonary Adenoma Resistance 1, a Major Genetic Determinant of Mouse Lung Adenoma Resistance
Authors: Wang Min , Zhang Zhongqiu , Zhang Zhuo , Vikis Haris , Yan Ying , Wang Yian , You Ming 
Published: March 2007

Abstract
Pulmonary adenoma resistance 1 (Par1) is a major genetic determinant of mouse lung adenoma resistance. Although Par1 was previously mapped to mouse chromosome 11 by conventional linkage analyses, its candidate region was broad and undefined. In our present study, we generated Par1 congenic mice using two mouse strains A/J (Par1/−) and Mus spretus (Par1/+). Analyzing these congenic mice enabled us to fine map the Par1 quantitative trait loci (QTL) into a 2.0-cM (2.2 Mb) chromosomal region between genetic marker D11Mit70 and the gene Hoxb9. We then conducted systematic candidate gene screening through nucleotide polymorphism and expression analyses. Genes showing differential lung tissue expression or carrying nonsynonymous single nucleotide polymorphisms were identified and discussed. In particular, we evaluated tumor suppressor gene Tob1 for its Par1 candidacy. Our findings have narrowed the Par1 QTL region and will greatly facilitate the identification of the major genetic determinant of mouse lung adenoma resistance. [Cancer Res 2007;67(6):2508–16]