bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the Lag Phase and Growth Rate of Listeria monocytogenes in Ground Ham Containing Sodium Lactate and Sodium Diacetate at Various Storage Temperatures
Authors: Hwang C.‐A. , Tamplin M.L.
Published: August 2007

ABSTRACT:  Refrigerated ready‐to‐eat (RTE) meats contaminated with Listeria monocytogenes were implicated in several listeriosis outbreaks. Lactate and diacetate have been shown to control L. monocytogenes in RTE meats. The objective of this study was to examine and model the effect of lactate (1.0% to 4.2%) and diacetate (0.05% to 0.2%) in ground ham on the lag phase duration (LPD, h) and growth rate (GR, log CFU/h) of L. monocytogenes at a range of temperatures (0 to 45 °C). A 6‐strain mixture of L. monocytogenes was inoculated into ground ham containing lactate and diacetate, and stored at various temperatures. The LPD and GR of L. monocytogenes in ham as affected by lactate, diacetate, and storage temperature were analyzed and accurately represented with mathematical equations. Resulting LPD and GR equations for storage temperatures within the range of 0 to 36 °C significantly represented the experimental data with a regression coefficient of 0.97 and 0.96, respectively. Significant factors (P < 0.05) that affected the LPD were temperature, lactate, diacetate, and the interactions of all three, whereas only temperature and the interactions between temperature and lactate and diacetate had a significant effect on GR. At suboptimal growth temperatures (≤12 °C) the increase of lactate and diacetate concentrations, individually or in combination, extended the LPD. The effect of higher concentrations of both additives on reducing the GR was observed only at temperatures that were more suitable for growth of L. monocytogenes, that is, 15 to 35 °C. These data may be used to assist in determining concentrations of lactate and diacetate in cooked ham products to control the growth of L. monocytogenes over a wide range of temperatures during manufacturing, distribution, and storage.
Bioactive Peptides Released from Saccharomyces cerevisiae under Accelerated Autolysis in a Wine Model System
Authors: Alcaide‐Hidalgo J.M. , Pueyo E. , Polo M.C. , Martínez‐Rodríguez A.J.
Published: August 2007

ABSTRACT:  The ACE inhibitory activity (IACE) and the oxygen radical absorbance capacity (ORAC‐FL) values of yeast peptides isolated from a model wine during accelerated autolysis of Saccharomyces cerevisiae have been studied. Samples were taken at 6, 24, 48, 121, and 144 h of autolysis. Peptide concentration increased throughout autolysis process. Peptides were fractionated into 2 fractions: F1, constituted by hydrophilic peptides, and F2, containing hydrophobic peptides. Both IACE activity and ORAC‐FL values increased during 121 h of autolysis, then decreased afterward. Peptide fraction F2 was the main fraction involved in IACE activity and ORAC‐FL.
Inactivation Kinetics ofEscherichia coliby Pulsed Electron Beam
Authors: Chalise P.R. , Hotta E. , Matak K.E. , Jaczynski J.
Published: August 2007

ABSTRACT: A novel and compact low‐energy (keV) high‐power pulsed electron beam (e‐beam) that utilizes a secondary emission electron gun (SEEG) was designed and constructed.Escherichia coliJM 109 at a concentration of 106CFU/mL was spread‐plated on Luria‐Bertani (LB) medium and subjected to the SEEG e‐beam. The e‐beam was administered as 1 or 5 pulses. The duration of a single pulse was constant at 5 μs, e‐beam current density was constant at 25 mA/cm2, and e‐beam energy varied between 60 and 82.5 keV. Following treatment with the SEEG e‐beam, survivors of the irradiatedE. colisamples were enumerated by a standard 10‐fold dilution and spread‐plated. The survivor curves were plotted on logarithmic scale as a function of e‐beam dose. TheD10‐values were calculated as a negative reciprocal of the slope of the survivor curves. TheD10‐values forE. coliinactivated with 1‐ and 5‐pulse SEEG e‐beam were 0.0026 and 0.0217 Gy, respectively. TheseD10‐values were considerably lower than publishedD10‐values forE. coliinactivated with conventional high‐energy continuous e‐beam, likely due to shorter exposure time (t), greater current density (J), and a pulse mode of the SEEG e‐beam. The SEEG e‐beam showed promising results for microbial inactivation in a nonthermal manner; however, due to low energy of the SEEG e‐beam, current applications are limited to surface decontamination. The SEEG e‐beam may be an efficient processing step for surface inactivation of food‐borne pathogens on ready‐to‐eat products, including fresh and leafy vegetables.
Effects of β‐Glucan Addition to a Probiotic Containing Yogurt
Authors: Vasiljevic T. , Kealy T. , Mishra V.K.
Published: August 2007

ABSTRACT:  This study investigated the effects of addition of β‐glucan from 2 different cereal sources (oat and barley) on growth and metabolic activity of Bifidobacterium animalis ssp. lactis (Bb‐12™) as determined by plating on a selective medium in yogurt during prolonged cold storage. These yogurt batches were compared to unsupplemented and inulin supplemented controls. All batches were also assessed for syneresis. Oat β‐glucan addition resulted in improved probiotic viability and stability comparable to that of inulin. It also enhanced lactic and propionic acid production. The barley β‐glucan addition suppressed proteolytic activity more than that from oat. These improvements were hindered by greater syneresis caused likely by thermodynamic incompatibility. Small amplitude oscillatory measurements of acidified model mixture of β‐glucan/skim milk solids showed formation of casein gel within the β‐glucan network. Binary mixtures of β‐glucan and skim milk solids had apparent pseudoplastic and non‐Newtonian behavior governed mainly by β‐glucan contribution. Above critical concentrations, the mixtures underwent phase separation with the lower phase rich in protein. The phase diagram also showed that the addition of β‐glucan may be possible at or below 0.24 w/w%.
Study of Protoporphyrin IX (PpIX) Pharmacokinetics After Topical Application of 5‐Aminolevulinic Acid in Urethral Condylomata Acuminata†
Authors: Wang Xiu‐Li , Wang Hong‐Wei , Huang Zheng , Stepp Herbert , Baumgartner Reinhold , Dannecker Christian , Hillemanns Peter
Published: August 2007

The pharmacokinetics of 5‐aminolevulinic acid (ALA)‐induced protoporphyrin IX (PpIX) in lesions of urethral condylomata acuminata were investigated. Sixty patients (20 to 60 years old, 48 male and 12 female) were divided randomly into five groups and received topic application of different concentrations of ALA solution (0.5%, 1%, 3%, 5% or 10%). Biopsy was performed between 1 and 7 h and specimens were subjected to histological, PpIX fluorescence and human papillomavirus (HPV) DNA typing analyses. Fluorescence examination confirmed that ALA‐induced PpIX fluorescence was dominantly distributed in the HPV‐infected epidermis. In contrast, only a minimal amount of PpIX fluorescence was detected in the dermis. The maximal fluorescence intensity was detected at 5 h incubation. Higher ALA concentration (e.g. 5% and 10%) produced a stronger intensity. These results suggest that the topical application of 5–10% ALA solution for 3–5 h is the optimal condition for the photodynamic therapy of urethral condylomata acuminata. The selective damage of the condylomata acuminata lesions in the epidermis without damaging the dermis ensures a better control of recurrence and side effects such as ulceration or scarring. DNA typing showed that all patients were positive for low risk‐HPV DNA and among them 18.3% of patients harbored high risk‐HPV DNA.
Comparison of Femtosecond Laser and Continuous Wave UV Sources for Protein–Nucleic Acid Crosslinking
Authors: Fecko Christopher J. , Munson Katherine M. , Saunders Abbie , Sun Guangxing , Begley Tadhg P. , Lis John T. , Webb Watt W.
Published: August 2007

Crosslinking proteins to the nucleic acids they bind affords stable access to otherwise transient regulatory interactions. Photochemical crosslinking provides an attractive alternative to formaldehyde‐based protocols, but irradiation with conventional UV sources typically yields inadequate product amounts. Crosslinking with pulsed UV lasers has been heralded as a revolutionary technique to increase photochemical yield, but this method had only been tested on a few protein–nucleic acid complexes. To test the generality of the yield enhancement, we have investigated the benefits of using ∼150 fs UV pulses to crosslink TATA‐binding protein, glucocorticoid receptor and heat shock factor to oligonucleotides in vitro. For these proteins, we find that the quantum yields (and saturating yields) for forming crosslinks using the high‐peak intensity femtosecond laser do not improve on those obtained with low‐intensity continuous wave (CW) UV sources. The photodamage to the oligonucleotides and proteins also has comparable quantum yields. Measurements of the photochemical reaction yields of several small molecules selected to model the crosslinking reactions also exhibit nearly linear dependences on UV intensity instead of the previously predicted quadratic dependence. Unfortunately, these results disprove earlier assertions that femtosecond pulsed laser sources provide significant advantages over CW radiation for protein–nucleic acid crosslinking.
Quantitative In Vitro Demonstration of Two‐Photon Photodynamic Therapy Using Photofrin® and Visudyne®
Authors: Khurana Mamta , Collins Hazel A. , Karotki Aliaksandr , Anderson Harry L. , Cramb David T. , Wilson Brian C.
Published: August 2007

Photodynamic therapy (PDT), the combined action of a photosensitizer and light to produce a cytotoxic effect, is an approved therapy for a number of diseases. At present, clinical PDT treatments involve one‐photon excitation of the photosensitizer. A major limitation is that damage may be caused to healthy tissues that have absorbed the drug and lie in the beam path. Two‐photon excitation may minimize this collateral damage, as the probability of absorption increases with the square of the light intensity, enabling spatial confinement of the photosensitizer activation. A potential application is the treatment of the wet‐form of age‐related macular degeneration, the foremost cause of central vision loss in the elderly.

Herein, the commercial photosensitizers Visudyne® and Photofrin® are used to demonstrate quantitative in vitro two‐photon PDT. A uniform layer of endothelial cells (YPEN‐1) was irradiated with a Ti:sapphire laser (300 fs, 865 nm, 90 MHz) using a confocal scanning microscope. Quantification of the two‐photon PDT effect was achieved using the permeability stain Hoechst 33258 and a SYTOX® Orange viability stain. Visudyne was found to be around seven times more effective as a two‐photon photosensitizer than Photofrin under the conditions used, consistent with its higher two‐photon absorption cross‐section. We also demonstrate for the first time the quadratic intensity dependence of cellular two‐photon PDT. This simple in vitro method for quantifying the efficacy of photosensitizers for two‐photon excited PDT will be valuable to test specifically designed two‐photon photosensitizers before proceeding to in vivo studies in preclinical animal models.
Time‐Resolved and Steady‐State Fluorescence Spectroscopy of Eumelanin and Indolic Polymers
Authors: Nighswander‐Rempel Stephen P. , Mahadevan Indumathy B. , Rubinsztein‐Dunlop Halina , Meredith Paul
Published: August 2007

Eumelanin plays a variety of important physiological roles in human skin. However, its structure and fundamental properties still remain poorly understood. Although the absorbance of eumelanin is broad and reveals little about its structure, a variety of techniques have revealed the presence of a disordered array of chromophores within the melanin compound. In order to examine the fluorescence decay dynamics of these chromophores, time‐resolved spectroscopy was applied to solutions of synthetic eumelanin and a melanin‐like polymer of N‐methyl,5‐hydroxy,6‐methoxyindole (N‐Me‐5H6MI). Solutions were excited with 80 fs laser pulses at 355, 370, 390 and 400 nm, and decay time courses were acquired at 20 nm intervals between 400 and 600 nm for each excitation wavelength. Decay profiles for both eumelanin and the polymer exhibited a characteristic multiexponential behavior with decay times between 0.5 and 15 ns, although steady‐state spectra for the polymer exhibited only two peaks. The long‐decay component in the polymer showed a significant decrease in both amplitude (30–5%) and decay time (14–6 ns) with increasing emission wavelength. In contrast, the amplitude and decay time in melanin increased slightly (10–15% and 7–10 ns, respectively) from 400 to 520 nm emission, at which point they leveled off. These trends were consistent for all excitation wavelengths. These results suggest that the multiexponential behavior of melanin fluorescence is characteristic of each oligomer within the eumelanin compound, and is consistent with the assertion that the diversity of constituents within eumelanin provides it with a robustness in spectral properties.
Photophysics and Multifunctionality of Hypericin‐Like Pigments in Heterotrich Ciliates: A Phylogenetic Perspective
Authors: Lobban Christopher S. , Hallam Steven J. , Mukherjee Prasun , Petrich Jacob W.
Published: August 2007

In this paper, we review the literature and present some new data to examine the occurrence and photophysics of the diverse hypericin‐like chromophores in heterotrichs, the photoresponses of the cells, the various roles of the pigments and the taxa that might be studied to advance our understanding of these pigments. Hypericin‐like chromophores are known chemically and spectrally so far only from the stentorids and Fabrea, the latter now seen to be sister to stentorids in the phylogenetic tree. For three hypericin‐like pigments, the structures are known but these probably do not account for all the colors seen in stentorids. At least eight physiological groups of Stentor exist depending on pigment color and presence/absence of zoochlorellae, and some species can be bleached, leading to many opportunities for comparison of pigment chemistry and cell behavior. Several different responses to light are exhibited among heterotrichs, sometimes by the same cell; in particular, cells with algal symbionts are photophilic in contrast to the well‐studied sciaphilous (shade‐loving) species. Hypericin‐like pigments are involved in some well‐known photophobic reactions but other pigments (rhodopsin and flavins) are also involved in photoresponses in heterotrichs and other protists. The best characterized role of hypericin‐like pigments in heterotrichs is in photoresponses and they have at least twice evolved a role as photoreceptors. However, hypericin and hypericin‐like pigments in diverse organisms more commonly serve as predator defense and the pigments are multifunctional in heterotrichs. A direct role for the pigments in UV protection is possible but evidence is equivocal. New observations are presented on a folliculinid from deep water, including physical characterization of its hypericin‐like pigment and its phylogenetic position based on SSU rRNA sequences. The photophysics of hypericin and hypericin‐like pigments is reviewed. Particular attention is given to how their excited‐state properties are modified by the environment. Dramatic changes in excited‐state behavior are observed as hypericin is moved from the homogeneous environment of organic solvents to the much more structured surroundings provided by the complexes it forms with proteins. Among these complexes, it is useful to consider the differences between environments where hypericin is not found naturally and those where it is, notably, for example, in heterotrichs. It is clear that interaction with a protein modifies the photophysics of hypericin and understanding the molecular basis of this interaction is one of the outstanding problems in elucidating the function of hypericin and hypericin‐like chromophores.
Photochemistry of 5‐Fluorouracil Dideoxyribonucleoside Monophosphate
Authors: Faichuk Melissa , Mah Allison , Loppnow Glen R.
Published: August 2007

5‐Fluorouracil is an artificial nucleobase analog of thymine and uracil, with a substituent in the 5‐position that has a mass similar to the methyl group in thymine, but very different electronic, steric and vibrational coupling properties. UVC irradiation of 5‐fluorouracil dideoxyribonucleoside monophosphate (dXpdX) is examined here with mass spectrometry and UV–Vis absorption spectroscopy and is compared to the UV photochemistry of other pyrimidine dideoxyribonucleoside monophosphates. The results show that the photochemical products and kinetics of dXpdX are similar to those of uracil dideoxyribonucleoside monophosphate and similar to those of the isolated 5‐fluorouracil nucleobase. The photochemistry of dXpdX is compared to the photochemistry of thymine and uracil dideoxyribonucleoside monophosphates.
Measuring thrombin generation based sensitivity to activated protein C using an automated coagulometer (ACL 9000)
Authors: GARDINER C. , MACHIN S. J. , MACKIE I. J.
Published: August 2007

Increased thrombin generation in the presence of activated protein C (APC) is known to be an independent risk factor for thrombosis. Although commercially available methods for measuring thrombin generation are available, none measure sensitivity to APC. We have developed an automated thrombin generation based APC sensitivity test, for use with defibrinated plasma using the automated coagulometer (ACL9000). A chromogenic substrate that is cleaved by thrombin at a slow rate, 7 pm tissue factor and 20 μm phospholipid (DOPC : DOPE : DOPS, 60 : 20 : 20) with and without 5 nm APC. Thrombin generation with [endogenous thrombin potential (ETP)+APC] and without APC (ETP), was expressed as a ratio relative to pooled normal plasma. Normal reference ranges were established in 30 normal subjects: ETP 0.73–1.06; ETP+APC 0.42–1.07. ETP+APC was found to be sensitive to factor V Leiden, oral contraceptive use, low levels of protein S and tissue factor pathway inhibitor and increased plasma factor VIII.
Stuttering priapism complicating Warfarin therapy in a patient with protein C deficiency
Authors: ABU SHAM’A R. A. H. , KUFRI F. H. , YASSIN I. H.
Published: August 2007

Priapism is a rare disorder defined as a persistent penile erection that continues hours beyond, or is unrelated to, sexual stimulation. There are two types of priapism; ischemic low‐flow type or non‐ischemic high flow, with differing etiologies. Priapism associated with thrombophilia is a well‐recognized entity. However, the pathogenesis of this association is not fully understood. We report a rare case of recurrent (stuttering) priapism in a patient with protein C deficiency while maintained on Warfarin therapy. This therapy was also complicated by Warfarin‐induced skin necrosis.
Very early onset of an acute myeloid leukemia in an adult patient with B‐cell lymphoblastic leukemia
Authors: SHIVAROV V. , STOIMENOV A. , GALABOVA I. , BALATZENKO G. , GUENOVA M.
Published: August 2007

We report on a case of a 30‐year‐old male with acute B‐lymphoblastic leukemia (B‐ALL) with immunophenotype CD19+, CD22+, CD20+, CD10+, with aberrant expression of CD13 and CD117, and IgH gene rearrangements. Three months after treatment with GMALL‐2003 and Ida/FLAG protocols bone marrow showed predominance of blasts with myeloid morphology and phenotype MPO+, CD13+, CD33+, CD64+, CD15+, CD56+, EVI‐1 gene overexpression and lack of IgH rearrangements. The case is the first report of a very early emergence of myeloid leukemia during the induction treatment for B‐ALL in an adult patient. Different pathogenetic mechanisms are discussed – clonal evolution or selection, lineage switch or development of a de novo or therapy‐induced leukemia.
Discovery of Novel DNA Gyrase Inhibitors by High-Throughput Virtual Screening
Authors: Ostrov David A. , Hernández Prada José A. , Corsino Patrick E. , Finton Kathryn A. , Le Nhan , Rowe Thomas C.
Published: August 2007

The bacterial type II topoisomerases DNA gyrase and topoisomerase IV are validated targets for clinically useful quinolone antimicrobial drugs. A significant limitation to widely utilized quinolone inhibitors is the emergence of drug-resistant bacteria due to an altered DNA gyrase. To address this problem, we have used structure-based molecular docking to identify novel drug-like small molecules that target sites distinct from those targeted by quinolone inhibitors. A chemical ligand database containing approximately 140,000 small molecules (molecular weight, <500) was molecularly docked onto two sites of
Escherichia coli
DNA gyrase targeting (i) a previously unexplored structural pocket formed at the dimer interface of subunit A and (ii) a small region of the ATP binding pocket on subunit B overlapping the site targeted by coumarin and cyclothialidine drugs. This approach identified several small-molecule compounds that inhibited the DNA supercoiling activity of purified
E. coli
DNA gyrase. These compounds are structurally unrelated to previously identified gyrase inhibitors and represent potential scaffolds for the optimization of novel antibacterial agents that act on fluoroquinolone-resistant strains.
Optimization of the Dosage of Flucytosine in Combination with Amphotericin B for Disseminated Candidiasis: a Pharmacodynamic Rationale for Reduced Dosing
Authors: Hope William W. , Warn Peter A. , Sharp Andrew , Reed Paul , Keevil Brian , Louie Arnold , Walsh Thomas J. , Denning David W. , Drusano George L.
Published: August 2007

Amphotericin B and flucytosine (5FC) have an additive effect when used for disseminated candidiasis. Here, we bridge the results of an experimental pharmacodynamic study to humans and demonstrate that a 5FC dosage of 25 mg/kg of body weight/day in four divided doses in combination with amphotericin B produces near-maximal effect.
Pseudomonas aeruginosa
May Accumulate Drug Resistance Mechanisms without Losing Its Ability To Cause Bloodstream Infections
Authors: Hocquet Didier , Berthelot Philippe , Roussel-Delvallez Micheline , Favre Roger , Jeannot Katy , Bajolet Odile , Marty Nicole , Grattard Florence , Mariani-Kurkdjian Patricia , Bingen Edouard , Husson Marie-Odile , Couetdic Gérard , Plésiat Patrick
Published: August 2007

In this study, we systematically investigated the resistance mechanisms to β-lactams, aminoglycosides, and fluoroquinolones of 120 bacteremic strains of
Pseudomonas aeruginosa
. Pulsed-field gel electrophoresis genotyping showed that 97 of these strains were represented by a single isolate, 10 by 2 and 1 by 3 clonally related isolates, respectively. Seventy-five percent (90 out of 120) of the bacteremic
P. aeruginosa
strains displayed a significant resistance to one or more of the tested antimicrobials (up to 11 for 1 strain). These strains were found to harbor a great diversity of resistance mechanisms (up to 7 in 1 strain), leading to various levels of drug resistance. Interestingly, 11 and 36% of the isolates appeared to overproduce the MexAB-OprM and MexXY-OprM efflux systems, respectively. Altogether, our results show that
P. aeruginosa
may accumulate intrinsic (overproduction of cephalosporinase AmpC, increased drug efflux, fluoroquinolone target mutations, and deficient production of porin OprD) and exogenous (production of secondary β-lactamases and aminoglycoside-modifying enzymes) resistance mechanisms without losing its ability to generate severe bloodstream infections. Consequently, clinicians should be aware that multidrug-resistant
P. aeruginosa
may remain fully pathogenic.
Ehrlichia canis
gp200 Contains Dominant Species-Specific Antibody Epitopes in Terminal Acidic Domains
Authors: Nethery Kimberly A. , Doyle C. Kuyler , Zhang Xiaofeng , McBride Jere W.
Published: August 2007

Species-specific antibody epitopes within several major immunoreactive protein orthologs of
Ehrlichia
species have recently been identified and molecularly characterized. In this study, dominant B-cell epitopes within the acidic (pI 5.35) ankyrin repeat-containing 200-kDa major immunoreactive protein (gp200) of
Ehrlichia canis
were defined. The
E. canis
gp200 gene (4,263 bp; 1,421 amino acids) was cloned and expressed as four (N-terminal, 1,107 bp; N-internal, 910 bp; C-internal, 1,000 bp; and C-terminal, 1,280 bp) overlapping recombinant proteins. The N-terminal, C-internal, and C-terminal polypeptides (369, 332, and 426 amino acids, respectively) were strongly recognized by antibody, and the major epitope(s) in these polypeptides was mapped to four polypeptide regions (40 to 70 amino acids). Smaller overlapping recombinant polypeptides (14 to 15 amino acids) spanning these regions identified five strongly immunoreactive species-specific epitopes that exhibited conformational dependence. The majority of the epitopes (four) were located in two strongly acidic (pI 4 to 4.9) domains in the distal N- and C-terminal regions of the protein flanking the centralized ankyrin domain-containing region. The amino acid content of the epitope-containing domains included a high proportion of strongly acidic amino acids (glutamate and aspartate), and these domains appear to have important biophysical properties that influence the antibody response to gp200.
Listeriolysin O Secreted byListeria monocytogenesinto the Host Cell Cytosol Is Degraded by the N-End Rule Pathway
Authors: Schnupf Pamela , Zhou Jianmin , Varshavsky Alexander , Portnoy Daniel A.
Published: August 2007

The intracellular pathogenListeria monocytogenesescapes from a phagosomal compartment into the cytosol by secreting the pore-forming cytolysin listeriolysin O (LLO). During the proliferation ofL. monocytogenesbacteria in the mammalian cell cytosol, the secreted LLO is targeted for degradation by the ubiquitin system. We report here that LLO is a substrate of the ubiquitin-dependent N-end rule pathway, which recognizes LLO through its N-terminal Lys residue. Specifically, we demonstrated by reverse-genetic and pharmacological methods that LLO was targeted for degradation by the N-end rule pathway in reticulocyte extracts and mouse NIH 3T3 cells and after its secretion by intracellular bacteria into the mouse cell cytosol. Replacing the N-terminal Lys of LLO with a stabilizing residue such as Val increased the in vivo half-life of LLO but did not strongly affect the intracellular growth or virulence ofL. monocytogenes. Nevertheless, this replacement decreased the virulence ofL. monocytogenesby nearly twofold, suggesting that a destabilizing N-terminal residue of LLO may stem from positive selection during the evolution of this and related bacteria. A double mutant strain ofL. monocytogenesin which upregulated secretion of LLO was combined with a stabilizing N-terminal residue was severely toxic to infected mammalian cells, resulting in reduced intracellular growth of bacteria and an ∼100-fold-lower level of virulence. In summary, we showed that LLO is degraded by the N-end rule pathway and that the degradation of LLO can reduce the toxicity ofL. monocytogenesduring infection, a property of LLO that may have been selected for its positive effects on fitness during the evolution ofL. monocytogenes.
UNSTEADY FLOW IN A 3D CENTRALLY-ACTUATED TYPE ARTIFICIAL HEART
Authors: YANG X. L. , LIU Y. , YANG J. M.
Published: August 2007

The unsteady flow within a simplified 3D centrally-actuated type artificial heart was investigated numerically using moving boundary technique. The velocities on the inlet and outlet were determined according to the motion of the diaphragm. The case with heart beat rate of 75 beats per minute (bpm) was simulated. Two models were studied. It is found that, in the diastolic cycle, a vortex ring forms in the conjunction of the blood chamber and the inlet tube. This vortex ring can provide good wash-out on the wall.
SIMULATING TWO- AND THREE-DIMENSIONAL MICROFLOWS BY THE LATTICE BOLTZMANN METHOD WITH KINETIC BOUNDARY CONDITIONS
Authors: TANG G. H. , TAO W. Q. , HE Y. L.
Published: August 2007

An entropic lattice Boltzmann model for gaseous slip flow in microchannels is presented. We relate the Knudsen number with the relaxation time in the lattice Boltzmann evolution equation from the gas kinetic theory. The slip velocity taking the momentum accommodation coefficient into account at the solid boundaries is obtained with kinetic boundary conditions. The two-dimensional micro-Poiseuille flow, microflow over a backward-facing step, micro-lid-driven cavity flow, and three-dimensional microflow are simulated using the present model. Numerical tests show that the results of the present lattice Boltzmann method together with the boundary scheme are in good agreement with the analytical solutions and numerical simulations by the finite volume method.
GAMES OF LENGTH ω1
Authors: NEEMAN ITAY
Published: August 2007

We prove determinacy for open length ω1 games. Going further we introduce, and prove determinacy for, a stronger class of games of length ω1, with payoff conditions involving the entire run, the club filter on ω1, and a sequence of ω1 disjoint stationary subsets of ω1. The determinacy proofs use an iterable model with a class of indiscernible Woodin cardinals, and we show that the games precisely capture the theory of the minimal model for this assumption.
Comparison of Envelope-Related Genes in Unicellular and Filamentous Cyanobacteria
Authors: Yang Yu , Qin Song , Zhao Fangqing , Chi Xiaoyuan , Zhang Xiaowen
Published: August 2007

To elucidate the evolution of cyanobacterial envelopes and the relation between gene content and environmental adaptation, cell envelope structures and components of unicellular and filamentous cyanobacteria were analyzed in comparative genomics. Hundreds of envelope biogenesis genes were divided into 5 major groups and annotated according to their conserved domains and phylogenetic profiles. Compared to unicellular species, the gene numbers of filamentous cyanobacteria expanded due to genome enlargement effect, but only few gene families amplified disproportionately, such as those encoding waaG and glycosyl transferase 2. Comparison of envelope genes among various species suggested that the significant variance of certain cyanobacterial envelope biogenesis genes should be the response to their environmental adaptation, which might be also related to the emergence of filamentous shapes with some new functions.
A Family of Heat Functions as Solutions of Indeterminate Moment Problems
Authors: Gómez Ricardo , López-García Marcos
Published: August 2007

We construct a family of functions satisfying the heat equation and show how they can be used to generate solutions to indeterminate moment problems. The following cases are considered: log-normal, generalized Stieltjes-Wigert, andq-Laguerre.
Expression of VE-Cadherin in Peritubular Endothelial Cells during Acute Rejection after Human Renal Transplantation
Authors: Roussoulières Ana , McGregor Brigitte , Chalabreysse Lara , Cerutti Catherine , Garnier Jeanne-Luce , Boissonnat Pascale , Bastien Olivier , Scoazec Jean-Yves , Thivolet-Bejui Françoise , Sebbag Laurent , McGregor John L.
Published: August 2007

Genes involved in acute rejection (AR) after organ transplantation remain to be further elucidated. In a previous work we have demonstrated the under-expression of VE-Cadherin by endothelial cells (EC) in AR following murine and human heart transplantation. Serial sections from 15 human kidney Banff-graded transplant biopsies were examined for the presence of VE-Cadherin and CD34 staining by immunohistochemistry (no AR (n=5), AR grade IA (n=5), or AR grade IIA (n=5)). Quantification of peritubular EC staining were evaluated and results were expressed by the percentage of stained cells per surface analysed. There was no difference in CD34 staining between the 3 groups. VE-Cadherin expression was significantly reduced in AR Grade IIA when compared to no AR (P=.01) and to AR grade IA (P=.02). This study demonstrates a reduced VE-Cadherin expression by EC in AR after renal transplantation. The down-regulation of VE-Cadherin may strongly participate in human AR.
Generalized Derivations of Prime Rings
Authors: Shuliang Huang
Published: August 2007

LetRbe an associative prime ring,Ua Lie ideal such thatu2∈Ufor allu∈U. An additive functionF:R→Ris called a generalized derivation if there exists a derivationd:R→Rsuch thatF(xy)=F(x)y+xd(y)holds for allx,y∈R. In this paper, we prove thatd=0orU⊆Z(R)if any one of the following conditions holds: (1)d(x)∘F(y)=0, (2)[d(x),F(y)=0], (3) eitherd(x)∘F(y)=x∘yord(x)∘F(y)+x∘y=0, (4) eitherd(x)∘F(y)=[x,y]ord(x)∘F(y)+[x,y]=0, (5) eitherd(x)∘F(y)−xy∈Z(R)ord(x)∘F(y)+xy∈Z(R), (6) either[d(x),F(y)]=[x,y]or[d(x),F(y)]+[x,y]=0, (7) either[d(x),F(y)]=x∘yor[d(x),F(y)]+x∘y=0for allx,y∈U.
Roles of Retinoids and Retinoic Acid Receptors in the Regulation of Hematopoietic Stem Cell Self-Renewal and Differentiation
Authors: Purton Louise E.
Published: August 2007

Multipotent hematopoietic stem cells (HSCs) sustain blood cell production throughout an individual's lifespan through complex processes ultimately leading to fates of self-renewal, differentiation or cell death decisions. A fine balance between these decisions in vivo allows for the size of the HSC pool to be maintained. While many key factors involved in regulating HSC/progenitor cell differentiation and cell death are known, the critical regulators of HSC self-renewal are largely unknown. In recent years, however, a number of studies describing methods of increasing or decreasing the numbers of HSCs in a given population have emerged. Of major interest here are the emerging roles of retinoids in the regulation of HSCs.
Risk of Bladder Cancer Associated with Family History of Cancer: Do Low-Penetrance Polymorphisms Account for the Increase in Risk?
Authors: Murta-Nascimento Cristiane , Silverman Debra T. , Kogevinas Manolis , García-Closas Montserrat , Rothman Nathaniel , Tardón Adonina , García-Closas Reina , Serra Consol , Carrato Alfredo , Villanueva Cristina , Dosemeci Mustafa , Real Francisco X. , Malats Núria
Published: August 2007

The relationship between family history of cancer in first-degree relatives and risk of bladder cancer was examined in the Spanish Bladder Cancer Study. Information on family history of cancer was obtained for 1,158 newly diagnosed bladder cancer cases and 1,244 controls included in 18 hospitals between 1998 and 2001. A total of 464 (40.1%) cases and 436 (35.1%) controls reported a family history of cancer in ≥1 relative [odds ratio (OR), 1.32; 95% confidence interval (95% CI), 1.11-1.59]; the OR was 1.23 (95% CI, 1.01-1.50) among those with only one relative affected and 1.67 (95% CI, 1.23-2.29) among those with ≥2 affected relatives (Ptrend = 0.0004). A greater risk of bladder cancer was observed among those diagnosed at age ≤45 years (OR, 2.67; 95% CI, 1.10-6.50) compared with those diagnosed over age 45 years (OR, 1.27; 95% CI, 1.06-1.52). The OR of bladder cancer among subjects reporting a family history of cancer of the bladder was 2.34 (95% CI, 0.95-5.77). Statistically significant associations emerged between bladder cancer risk and family history of cancer of the esophagus, lung, prostate, and brain. The OR of bladder cancer for those reporting family history of bladder cancer was 4.76 (95% CI, 1.25-18.09) among NAT2-slow acetylators and 1.17 (95% CI, 0.17-7.86) among NAT2-rapid/intermediate acetylators (Pinteraction = 0.609). Among individuals with GSTM1 null and present genotypes, the corresponding ORs were 2.91 (95% CI, 0.44-19.09) and 4.21 (95% CI, 1.26-14.14), respectively (Pinteraction = 0.712). Limitations of our study are small sample size in subgroup analyses, reliability of family history data, and possible residual confounding by shared environmental exposures. Overall, our findings support the hypothesis that genetic factors play a role in bladder cancer etiology. Whether these correspond to low-penetrance cancer-predisposing polymorphisms acting together and/or interacting with environmental factors warrants further research. (Cancer Epidemiol Biomarkers Prev 2007;16(8):1595–600)
Modulation of Human Glutathione S-Transferases by Polyphenon E Intervention
Authors: Chow H.-H. Sherry , Hakim Iman A. , Vining Donna R. , Crowell James A. , Tome Margaret E. , Ranger-Moore James , Cordova Catherine A. , Mikhael Dalia M. , Briehl Margaret M. , Alberts David S.
Published: August 2007

Purpose: Green tea consumption has been associated with decreased risk of certain types of cancers in humans. Induction of detoxification enzymes has been suggested as one of the biochemical mechanisms responsible for the cancer-preventive effect of green tea. We conducted this clinical study to determine the effect of repeated green tea polyphenol administration on a major group of detoxification enzymes, glutathione S-transferases (GST).

Methods: A total of 42 healthy volunteers underwent a 4-week washout period by refraining from tea or tea-related products. At the end of the washout period, a fasting blood sample was collected, and plasma and lymphocytes were isolated for assessment of GST activity and level. Following the baseline evaluation, study participants underwent 4 weeks of green tea polyphenol intervention in the form of a standardized Polyphenon E preparation at a dose that contains 800 mg epigallocatechin gallate (EGCG) once a day. Polyphenon E was taken on an empty stomach to optimize the oral bioavailability of EGCG. Upon completion of the intervention, samples were collected for postintervention GST assessment.

Results: Four weeks of Polyphenon E intervention enhanced the GST activity in blood lymphocytes from 30.7 ± 12.2 to 35.1 ± 14.3 nmol/min/mg protein, P = 0.058. Analysis based on baseline activity showed that a statistically significant increase (80%, P = 0.004) in GST activity was observed in individuals with baseline activity in the lowest tertile, whereas a statistically significant decrease (20%, P = 0.02) in GST activity was observed in the highest tertile. In addition, Polyphenon E intervention significantly increased the GST-π level in blood lymphocytes from 2,252.9 ± 734.2 to 2,634.4 ± 1,138.3 ng/mg protein, P = 0.035. Analysis based on baseline level showed that this increase was only significant (P = 0.003) in individuals with baseline level in the lowest tertile, with a mean increase of 80%. Repeated Polyphenon E administration had minimal effects on lymphocyte GST-μ and plasma GST-α levels. There was a small but statistically significant decrease (8%, P = 0.003) in plasma GST-α levels in the highest tertile.

Conclusions: We conclude that 4 weeks of Polyphenon E administration resulted in differential effects on GST activity and level based on baseline enzyme activity/level, with GST activity and GST-π level increased significantly in individuals with low baseline enzyme activity/level. This suggests that green tea polyphenol intervention may enhance the detoxification of carcinogens in individuals with low baseline detoxification capacity. (Cancer Epidemiol Biomarkers Prev 2007;16(8):1662–6)
Interleukin-10 Gene (IL10) Polymorphisms and Human Papillomavirus Clearance among Immunosuppressed Adolescents
Authors: Shrestha Sadeep , Wang Chengbin , Aissani Brahim , Wilson Craig M. , Tang Jianming , Kaslow Richard A.
Published: August 2007

Persistent infection with high-risk human papillomavirus (HPV) is a major risk factor for cervical cancer, and HPV clearance seems to be under host genetic influence. This study evaluated associations between three single nucleotide polymorphisms in the IL10 promoter and clearance of low- or high-risk HPV infection in a cohort of 226 largely HIV-1–infected African-American adolescent females. Among immunosuppressed individuals (HIV-1 seropositive and CD4+ ≤ 500), the GCC haplotype in the IL10 promoter was associated with reduced clearance of high-risk HPV16-like [relative hazard (RH), 0.46; 95% confidence interval (95% CI), 0.25-0.85; P = 0.01], HPV18-like (RH, 0.33; 95% CI, 0.16-0.67; P = 0.002), and any high-risk type (RH, 0.37; 95% CI, 0.20-0.68; P = 0.002) but not with low-risk HPV type (RH, 0.60; 95% CI, 0.29-1.25; P = 0.17). No associations were observed among immunocompetent individuals. The IL10 GCC haplotype has been associated with production of relatively high levels of interleukin (IL)-10, which could (a) inhibit cytokines such as IL-2, TNF-α, IL-4, IL-6, and IL-12 that are involved in the TH1-TH2 immunoregulation; (b) down-regulate expression of MHC class I and class II molecules; or (c) induce the transcription of early promoter of HPV, all potentially contributing to duration of HPV infection among immunosuppressed individuals. These results support the hypothesis that IL10 polymorphisms influence the clearance of infection with high-risk HPV types and warrant further studies of host genetic control of HPV pathogenesis and cervical cancer in the context of immunosuppression. (Cancer Epidemiol Biomarkers Prev 2007;16(8):1626–32)
DNA Quantification of Whole Genome Amplified Samples for Genotyping on a Multiplexed Bead Array Platform
Authors: Hansen Helen M. , Wiemels Joseph L. , Wrensch Margaret , Wiencke John K.
Published: August 2007

Whole genome amplification (WGA) permits genotyping DNA samples of limited quantity, expanding the number of samples available for genetic epidemiology studies. WGA, however, produces various nucleic acid side products that may interfere with accurate DNA quantification and further analysis. Although quality control of whole genome amplified DNA (wgaDNA) before genotyping is essential to prevent failed or poor genotyping results, little information is available to choose the best method for wgaDNA quantification. Therefore, we quantified wgaDNA from 54 buccal or poor quality blood samples by four methods: UV absorbance, PicoGreen fluorescence calibrated with λ bacteriophage or calf thymus DNA, and absolute quantification by real-time PCR amplification of human-specific Alu Yd6. We then genotyped these wgaDNA samples and paired high-quality genomic DNA samples on a custom 384-plex Illumina Golden Gate Panel. Of the 54 paired samples, 39 gave high concordance (>99%), whereas 7 had moderate concordance (>90-99%) and 8 had poor concordance (≤90%) of wgaDNA and genomic DNA genotyping results. Quantitative PCR of Alu was the only wgaDNA quantification method to distinguish wgaDNA samples that gave high, moderate, or low concordance results (i.e., wgaDNA quantities in the high, moderate, and poor concordance groups ranged at 4.14-118.32, 0.29-2.19, and 0.01-0.27 ng/μL, respectively). Human-specific quantitative PCR is a highly useful guide for determining the suitability of wgaDNA before high-throughput single-nucleotide polymorphism analysis. (Cancer Epidemiol Biomarkers Prev 2007;16(8):1686–90)
Maximizing the Benefits of Model-Based Period Analysis of Cancer Patient Survival
Authors: Brenner Hermann , Hakulinen Timo
Published: August 2007

Period analysis has been shown to provide more up-to-date estimates of cancer survival than traditional methods of survival analysis. There is, however, a tradeoff between up-to-dateness and precision of period survival estimates: increasing up-to-dateness by restricting the analysis to a relatively short period, such as the most recent calendar year, goes along with loss of precision. Recently, a model-based approach was proposed, in which more precise period survival estimates for the most recent year can be obtained through modeling of survival trends within a recent 5-year period. We assess possibilities to extend the time window used for modeling to come up with even more precise, but equally accurate and up-to-date estimates of prognosis. Empirical evaluation using data from the Finnish Cancer Registry shows that extension of the time window to about 10 years provides, in most cases, as accurate results as using a 5-year time window (whereas further extension may lead to considerably less accurate results in some cases). Using 10-year time windows for modeling, SEs of survival estimates can be approximately halved compared with conventional period survival estimates for the most recent calendar year. Furthermore, we present a modification of the modeling approach, which allows extension to 10-year time windows to be achieved without the need to include additional cohorts of patients diagnosed longer time ago and which provides similarly accurate survival estimates at comparable levels of precision in most cases. Our analyses indicate opportunities to further maximize benefits of model-based period analysis of cancer survival. (Cancer Epidemiol Biomarkers Prev 2007;16(8):1675–81)
A Method of Producing Carcinoma in Upper Aerodigestive Tree and Esophagus of the Syrian Golden Hamster Using Wounding and Instillation of N-Methylnitrosourea
Authors: Estensen Richard D. , Anderson W. Robert , Galbraith Arthur R. , Hartle Donna E. , Jordan Margaret M. , Ondrey Frank G. , Wattenberg Lee W.
Published: August 2007

Details of a method for producing carcinoma of the aerodigestive tree of the Syrian golden hamster and the use of this model to evaluate putative agents for chemoprevention of these carcinomas are described. The method produces a majority of squamous carcinomas of the trachea and glottis that follow squamous metaplasia of respiratory epithelium. In addition, seen are adenocarcinomas arising in glands of the respiratory tree. Squamous carcinomas of the digestive epithelium arise in primary squamous epithelium. These tumors of digestive epithelium have a growth pattern that differs from that of the respiratory epithelium in that they grow and invade without filling the epithelial layer with tumor cells.(Cancer Epidemiol Biomarkers Prev 2007;16(8):1644–50) (Cancer Epidemiol Biomarkers Prev 2007;16(8):1644–50)
Whole-Genome Amplification of Oral Rinse Self-Collected DNA in a Population-Based Case-Control Study of Breast Cancer
Authors: Liang Xueying , Trentham-Dietz Amy , Titus-Ernstoff Linda , Newcomb Polly A. , Welch Rober A. , Hutchinson Amy A. , Hampton John M. , Sutcliffe Cara B. , Haines Jonathan L. , Egan Kathleen M.
Published: August 2007

The availability of large amounts of genomic DNA (gDNA) is the limiting factor for many of the molecular biology assays in genetic epidemiologic studies. Whole-genome amplification using multiple displacement amplification is used to amplify a representative sample of gDNA from small amounts of gDNA to optimize gDNA yield. We collected oral rinse DNA samples through the mail from 3,377 women enrolled in a population-based U.S. breast cancer case-control study and did whole-genome amplification by multiple displacement amplification. Genotyping was done for 66 single nucleotide polymorphisms (SNP) in 18 candidate susceptibility genes using amplified DNA with genomic replicates included for quality control. The concordance rates (percentages of agreement) in 95 quality control replicates of gDNA and amplified DNA for 66 SNPs ranged from 88% to 100% (median, 97%). The average allelic error rate was 0.9%. However, in further analyses based on the full control series (n = 1,492), >60% of the SNPs failed tests for Hardy-Weinberg equilibrium (P < 0.05), with evidence of heterozygote loss in the great majority. Even eliminating the 9% of samples with lower quality or input DNA, tests for Hardy-Weinberg equilibrium indicated persistent allele bias in nearly a third of the SNPs. Whole-genome amplification may introduce substantial allele amplification bias in gDNA collected using a common protocol in population-based epidemiologic studies. (Cancer Epidemiol Biomarkers Prev 2007;16(8):1610–4)