bluuebunny/crossref_metadata_2025 huggingface dataset:
A Shielding Topology Stabilizes the Early Stage Protein–Mineral Complexes of Fetuin‐A and Calcium Phosphate: A Time‐Resolved Small‐Angle X‐ray Study
Authors: Rochette Christophe N. , Rosenfeldt Sabine , Heiss Alexander , Narayanan Theyencheri , Ballauff Matthias , Jahnen‐Dechent Willi
Published: February 2009

Biomineralization mechanisms: The serum protein α2‐HS glycoprotein/fetuin‐A is an important inhibitor that prevents pathological mineralization of calcium phosphate in soft tissues and in the extracellular fluid. TR‐SAXS and stopped‐flow analysis were used to monitor the growth of protein mineral particles nucleating from supersaturated salt solutions in the presence of the protein. It was found that fetuin‐A did not influence the formation of mineral nuclei, but did prevent the aggregation of nuclei and thus mineral precipitation.

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We report on the earliest stages of the formation of complexes of calcium phosphate in the presence of the serum protein α2‐HS glycoprotein/fetuin‐A termed calciprotein particles (CPPs). Time‐resolved small‐angle X‐ray scattering (TR‐SAXS) and stopped‐flow analysis were used to monitor the growth of protein mineral particles nucleating from supersaturated salt solutions. It was found that fetuin‐A did not influence the formation of mineral nuclei. However, fetuin‐A did prevent the aggregation of nuclei and thus mineral precipitation. Hence, fetuin‐A shielded spontaneously formed mineral nuclei, leading to stable calciprotein particles in the first stage of mineralization. Fetuin‐A is therefore critically required during the earliest stages of the formation of protein–mineral complexes in order to prevent uncontrolled mineralization.
“Click Peptide“: pH‐Triggered in Situ Production and Aggregation of Monomer Aβ1–42
Authors: Taniguchi Atsuhiko , Sohma Youhei , Hirayama Yuta , Mukai Hidehito , Kimura Tooru , Hayashi Yoshio , Matsuzaki Katsumi , Kiso Yoshiaki
Published: February 2009

Into neutral: We demonstrate the unique features of a pH click peptide based on an O‐acyl isopeptide method. Under acidic conditions, the click peptide remains in a monomeric form. Upon increase of the pH to 7.4, the click peptide is quickly able to convert into Aβ1–42 through an O‐to‐N intramolecular acyl migration. Further study using this pH click peptide would elucidate the pathological role of Aβ1–42 in Alzheimer's disease.

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The intense and uncontrollable self‐assembling nature of amyloid β peptide (Aβ) 1–42 is known to cause difficulties in preparing monomeric Aβ1–42; this results in irreproducible or discrepant study outcomes. Herein, we report novel features of a pH click peptide of Aβ1–42 that was designed to overcome these problems. The click peptide is a water‐soluble precursor peptide of Aβ1–42 with anO‐acyl isopeptide structure between the Gly25–Ser26 sequence. The click peptide adopts and retains a monomeric, random coil state under acidic conditions. Upon change to neutral pH (pH click), the click peptide converts to Aβ1–42 promptly (t1/2≈10 s) and quantitatively through an O‐to‐N intramolecular acyl migration. As a result of this quick and irreversible conversion, monomer Aβ1–42 with a random coil structure is produced in situ. Moreover, the oligomerization, amyloid fibril formation and conformational changes of the produced Aβ1–42 can be observed over time. This click peptide strategy should provide a reliable experimental system to investigate the pathological role of Aβ1–42 in Alzheimer's disease.
Lewis Acid Catalyzed Cascade Reactions of 1,6‐Diynes and 1,6‐Enynes with Vinylidenecyclopropanes
Authors: Yao Liang‐Feng , Shi Min
Published: February 2009

Cascade reactions: Lewis acid catalyzed cascade reactions of 1,6‐diynes and 1,6‐enynes with arylvinylidenecyclopropanes produce polycyclic compounds and isopropylidene‐3,3‐diarylcyclobut‐1‐enylmethyl derivatives (see scheme) in good to high yields along with a PtCl2‐catalyzed cyclization and a Cu(OAc)2⋅H2O‐catalyzed Eglinton coupling reaction.

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Lewis acid catalyzed reactions of N‐(4‐hydroxy‐4,4‐diarylbut‐2‐ynyl)‐4‐methyl‐N‐prop‐2‐ynylbenzenesulfonamides or 1,1‐diphenyl‐4‐prop‐2‐ynyloxybut‐2‐yn‐1‐ol (1,6‐diynes) 1 and N‐allyl‐N‐(4‐hydroxy‐4,4‐diarylbut‐2‐ynyl)‐4‐methylbenzenesulfonamides (1,6‐enynes) 2 with vinylidenecyclopropanes 3 selectively produce polycyclic compounds 4, 5 and 10 as well as isopropylidene‐3,3‐diarylcyclobut‐1‐enylmethyl derivatives 6 or 7 in good to high yields depending on the substituents on the benzene ring of 3 under mild conditions. An interesting PtCl2‐catalyzed cyclization of 6 and a Cu(OAc)2⋅H2O catalyzed Eglinton coupling reaction of 5 and 10 to produce the corresponding 5‐isopropylidene‐6‐methyl‐1‐(toluene‐4‐sulfonyl)‐7‐vinyl‐1,2,3,4,5,8‐hexahydroazocine derivatives 8 and the coupling products 9 and 11 in good yields have been disclosed, respectively. Plausible mechanisms of these processes have been proposed that belong to a cascade rearrangement followed by the Friedel–Crafts reaction, an intramolecular proton transferring and a cyclization reaction.
Stereoselectivity of the Hydrogen‐Atom Transfer in Benzophenone–Tyrosine Dyads: An Intramolecular Kinetic Solvent Effect
Authors: Hörner Gerald , Hug Gordon L. , Lewandowska Anna , Kazmierczak Franciszek , Marciniak Bronislaw
Published: February 2009

To be or not to be solvated is the decisive parameter that controls the photoinduced hydrogen‐atom transfer in diastereomeric ketone/phenol dyads. A kinetic solvent effect that refers to hydrogen bonding between the phenol and the solvent is suggested to be the main source of the stereoselective discrimination in the hydrogen transfer (see figure).

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Induction of a Melanoma‐Specific Antibody Response by a Monovalent, but not a Divalent, Synthetic GM2 Neoglycopeptide
Authors: Bay S. , Fort S. , Birikaki L. , Ganneau C. , Samain E. , Coïc Y‐M. , Bonhomme F. , Dériaud E. , Leclerc C. , Lo‐Man R.
Published: February 2009

Human tumor cell‐specific antibodies were induced in mice after immunization with a synthetic glycopeptide, which is based on the GM2 ganglioside carbohydrate moiety produced on a gram scale in bacteria. Such neoglycopeptides represent a promising cancer vaccine strategy for active immunotherapy targeting carbohydrates.

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The GM2 ganglioside represents an important target for specific anticancer immunotherapy. We designed and synthesized a neoglycopeptide immunogen displaying one or two copies of the GM2 tetrasaccharidic moiety. These glycopeptides were prepared using the Huisgen cycloaddition, which enables the efficient ligation of the alkyne‐functionalized biosynthesized GM2 with an azido CD4+ T cell epitope peptide. It is worth noting that the GM2 can be produced on a gram scale in bacteria, which can be advantageous for a scale‐up of the process. We show here for the first time that a fully synthetic glycopeptide, which is based on a ganglioside carbohydrate moiety, can induce human tumor cell‐specific antibodies after immunization in mice. Interestingly, the monovalent, but not the divalent, form of GM2 peptide construct induced antimelanoma antibodies. Unlike traditional vaccines, this vaccine is a pure chemically‐defined entity, a key quality for consistent studies and safe clinical evaluation. Therefore, such carbohydrate–peptide conjugate represents a promising cancer vaccine strategy for active immunotherapy targeting gangliosides.
Equal numbers of neuronal and nonneuronal cells make the human brain an isometrically scaled‐up primate brain
Authors: Azevedo Frederico A.C. , Carvalho Ludmila R.B. , Grinberg Lea T. , Farfel José Marcelo , Ferretti Renata E.L. , Leite Renata E.P. , Filho Wilson Jacob , Lent Roberto , Herculano‐Houzel Suzana
Published: February 2009

The human brain is often considered to be the most cognitively capable among mammalian brains and to be much larger than expected for a mammal of our body size. Although the number of neurons is generally assumed to be a determinant of computational power, and despite the widespread quotes that the human brain contains 100 billion neurons and ten times more glial cells, the absolute number of neurons and glial cells in the human brain remains unknown. Here we determine these numbers by using the isotropic fractionator and compare them with the expected values for a human‐sized primate. We find that the adult male human brain contains on average 86.1 ± 8.1 billion NeuN‐positive cells (“neurons”) and 84.6 ± 9.8 billion NeuN‐negative (“nonneuronal”) cells. With only 19% of all neurons located in the cerebral cortex, greater cortical size (representing 82% of total brain mass) in humans compared with other primates does not reflect an increased relative number of cortical neurons. The ratios between glial cells and neurons in the human brain structures are similar to those found in other primates, and their numbers of cells match those expected for a primate of human proportions. These findings challenge the common view that humans stand out from other primates in their brain composition and indicate that, with regard to numbers of neuronal and nonneuronal cells, the human brain is an isometrically scaled‐up primate brain. J. Comp. Neurol. 513:532–541, 2009. © 2009 Wiley‐Liss, Inc.
Chronic low‐level lead exposure affects the monoaminergic system in the mouse superior olivary complex
Authors: Fortune Tyler , Lurie Diana I.
Published: February 2009

Low‐level lead (Pb) exposure is associated with behavioral and cognitive dysfunction, but it is not clear how Pb produces these behavioral changes. Pb has been shown to alter auditory temporal processing in both humans and animals. Auditory temporal processing occurs in the superior olivary complex (SOC) in the brainstem, where it is an important component in sound detection in noisy environments and in selective auditory attention. The SOC receives a serotonergic innervation from the dorsal raphe, and serotonin has been implicated in auditory temporal processing within the brainstem and inferior colliculus. Because Pb exposure modulates auditory temporal processing, the serotonergic system is a potential target for Pb. The current study was undertaken to determine whether developmental Pb exposure preferentially changes the serotonergic system within the SOC. Pb‐treated mice were exposed to no Pb, very low Pb (0.01 mM), or low Pb (0.1 mM) throughout gestation and through 21 days postnatally. Brainstem sections from control and Pb‐exposed mice were immunostained for the vesicular monoamine transporter 2 (VMAT2), serotonin (5‐HT), and dopamine‐β‐hydroxylase (DβH; a marker for norepinephrine) in order to elucidate the effect of Pb on monoaminergic input into the SOC. Sections were also immunolabeled with antibodies to vesicular glutamate transporter 1 (VGLUT1), vesicular γ‐aminobutyric acid (GABA) transporter (VGAT), and vesicular acetylcholine transporter (VAChT) to determine whether Pb exposure alters the glutaminergic, GABAergic, or cholinergic systems. Pb exposure caused a significant decrease in VMAT2, 5‐HT, and DβH expression, whereas VGLUT1, VGAT, and VAChT showed no change. These results provide evidence that Pb exposure during development alters normal monoaminergic expression in the auditory brainstem. J. Comp. Neurol. 513:542–558, 2009. © 2009 Wiley‐Liss, Inc.
Entangling Light in its Spatial Degrees of Freedom with Four‐Wave Mixing in an Atomic Vapor
Authors: Boyer Vincent , Marino Alberto M. , Pooser Raphael C. , Lett Paul D.
Published: February 2009

Nonlinearities in atomic vaporsallow the production of “entangled images”—beams of light whose transverse light distributions exhibit localized correlations in their unavoidable quantum fluctuations (see picture). These spatially entangled beams may prove useful to reduce the noise in absorption imaging and beam positioning below the quantum noise level, as well as for quantum information applications.

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The entanglement properties of two beams of light can reside in subtle correlations that exist in the unavoidable quantum fluctuations of their amplitudes and phases. Recent advances in the generation of nonclassical light with four‐wave mixing in an atomic vapor have permitted the production and the observation of entanglement that is localized in almost arbitrary transverse regions of a pair of beams. These multi‐spatial‐mode entangled beams may prove useful for an array of applications ranging from noise‐free imaging and improved position sensing to quantum information processing.
Spectral, Structural, and Computational Studies of a New Family of Ruthenium(II) Complexes Containing Substituted 1,10‐Phenanthroline Ligands and in situ Electropolymerization of a Phenanthrolineruthenium(II) Complex Bridging Nanogap Gold Electrodes
Authors: Huang Wei , Wang Li , Tanaka Hirofumi , Ogawa Takuji
Published: February 2009

The synthesis and spectral and structural characterization of a new family of ruthenium(II) complexes containing 3‐bromo‐, 3,8‐dibromo‐, 3‐(thiophen‐2′,2″‐yl)‐, and 3,8‐(thiophen‐2′,2″‐yl)‐1,10‐phenanthroline (phen) ligands is described. UV/Vis spectroscopy is used to compare the differences between the conjugated π systems in these ligands and their respective [Ru(bpy)2]2+ (bpy = 2,2′‐bipyridine) analogs. Density functional theory (DFT) computations have been carried out to compare the energy differences between the single‐crystal and the energy‐minimized structures for different conformations (trans/trans, trans/cis and cis/cis) of the thiophene rings and their bonded phen ring. The formation of an oligothiophene semiconductor polymer bridging gold electrodes with a gap of around 25 nm gap from RuII complex 7 by in situ electropolymerization, and its removal, is monitored by scanning electron microscopy (SEM). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Regioselective C‐6 Hydrolysis of MethylO‐Benzoyl‐pyranosides Catalysed byCandida RugosaLipase
Authors: Esmurziev Aslan , Sundby Eirik , Hoff Bård Helge
Published: February 2009

Hydrolysis of six methylO‐benzoyl‐pyranosides has been investigated usingCandida rugosalipase in dioxane/buffer mixtures. The lipase catalysed the hydrolysis of all substrates in a regiospecific manner at C‐6. The rate of reaction was dependent on pyranoside structure, reaction temperature and scale, dioxane concentration and agitation speed. Starting from their C‐6O‐benzoyl precursors, the methyl 2,3,4‐tri‐O‐benzoyl‐pyranosides of α‐D‐galactose, β‐D‐galactose, α‐D‐glucose, and methyl 2,3‐di‐O‐benzoyl‐α‐D‐galactopyranoside could be isolated in 85–96 % yield. In hydrolysis of methyl 2,3,4,6‐tetra‐O‐benzoyl‐α‐D‐glucopyranoside and methyl 2,3,4,6‐tetra‐O‐benzoyl‐β‐D‐galactopyranoside substrate inhibition were observed, which in part could be overcome by increasing the reaction volume. Methyl 2,3,4,6‐tetra‐O‐benzoyl‐β‐D‐glucopyranoside and methyl 2,3,4,6‐tetra‐O‐benzoyl‐α‐D‐mannopyranoside were poor substrates forCandida rugosalipase and low degree of conversion towards products were obtained under all conditions. No acyl migration was detected in any of the products.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A Novel Galactosyltransferase Inhibitor with Diamino Sugar as a Pyrophosphate Mimic
Authors: Mitsuhashi Nobuyuki , Yuasa Hideya
Published: February 2009

Conjugates of 2,4‐diamino sugars and uridine have been synthesized as galactosyltransferase inhibitors. The relationship between inhibitory activity and the chelation abilility of the hinge‐like diamino sugar towards a metal ion was studied by NMR spectroscopy. One of the conjugates exhibited a moderate inhibition that ranks between those of UDP and UMP probably through the chelation of the hinge‐like diamino sugar to MnII. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of Enantioenriched Secondary and Tertiary Alcohols via Tricarbonylchromium(0) Complexes of Benzyl Allyl Ethers
Authors: Abecassis Keren , Gibson Susan E. , Martin‐Fontecha Mar
Published: February 2009

Allyl ethers of the tricarbonylchromium(0) complexes of benzylic alcohols undergo highly enantioselective benzylic functionalisation using a chiral base/electrophilic quench sequence; the allyl group is readily removed to reveal a hydroxy group as demonstrated in the syntheses of enantioenriched imidazole alcohols, a triol and a tertiary alcohol. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A research on used quantity of ground resistance reduction agent for ground systems
Authors: Chen Li‐Hsiung , Chen Jiann‐Fuh , Liang Tsorng‐Juu , Wang Wen‐I
Published: February 2009

The ground resistance reduction agent can be used to decrease ground resistance for high soil resistivity. The ground resistance decreases and the ground resistance reduction rate increases with increasing quantity of ground resistance reduction agent used. However, the ground resistance reduction effect will display the saturation phenomenon when the quantity of ground resistance reduction agent used increases to a certain level. This research discusses the quantity of ground resistance reduction agent used for ground rod. The used quantity of ground resistance reduction agent should be avoided in saturated areas to maximize the efficiency of ground resistance reduction agent use. Copyright © 2009 John Wiley & Sons, Ltd.
Fluid–solid interaction problems with thermal convection using the immersed element‐free Galerkin method
Authors: Pita Claudio M. , Felicelli Sergio D.
Published: February 2009

In this work, the immersed element‐free Galerkin method (IEFGM) is proposed for the solution of fluid–structure interaction (FSI) problems. In this technique, the FSI is represented as a volumetric force in the momentum equations. In IEFGM, a Lagrangian solid domain moves on top of an Eulerian fluid domain that spans over the entire computational region. The fluid domain is modeled using the finite element method and the solid domain is modeled using the element‐free Galerkin method. The continuity between the solid and fluid domains is satisfied by means of a local approximation, in the vicinity of the solid domain, of the velocity field and the FSI force. Such an approximation is achieved using the moving least‐squares technique. The method was applied to simulate the motion of a deformable disk moving in a viscous fluid due to the action of the gravitational force and the thermal convection of the fluid. An analysis of the main factors affecting the shape and trajectory of the solid body is presented. The method shows a distinct advantage for simulating FSI problems with highly deformable solids. Copyright © 2009 John Wiley & Sons, Ltd.
The symptom profile of vascular depression
Authors: Naarding Paul , Veereschild Mike , Bremmer Marijke , Deeg Dorly , Beekman Aartjan T. F.
Published: February 2009

Objectives

Vascular depression is regarded as a subtype of depression, especially in––but not limited strictly to––older persons, and characterized by a specific clinical presentation and an association with (cerebro)vascular risk and disease. It is also known that depression is a risk factor in the development of myocardial infarction. The possibility of identifying depressed subjects at risk of a first cardiac event by their clinical presentation in general practice would have significant implications.

Methods

We studied the baseline depression symptom profiles of subjects in the Longitudinal Aging Study Amsterdam and compared the profile of depressed subjects who had and had not suffered a first cardiac event at a follow‐up after eight years.

Results

We could not confirm the specific symptom profile in depressed subjects who suffered from a first cardiac event at follow‐up. Most notably, the presumed specific symptoms of vascular depression, psychomotor retardation, and anhedonia were not significantly associated with the occurrence of a first cardiac event at follow‐up.

Conclusions

In this large community study we failed to identify a difference in the depression symptom profile between incident cardiac and non‐cardiac cases. Copyright © 2009 John Wiley & Sons, Ltd.
Primary care and dementia: 1. diagnosis, screening and disclosure
Authors: Iliffe Steve , Robinson Louise , Brayne Carol , Goodman Claire , Rait Greta , Manthorpe Jill , Ashley Peter
Published: February 2009

Objectives

To write a narrative review of the roles of primary care practitioners in caring for people with dementia in the community.

Methods

The systematic review carried out for the NICE/SCIE Guidelines was updated from January 2006, Cochrane Reviews were identified, and other publications found by consultation with experts.

Results

The insidious and very variable development of dementia syndromes makes recognition of the syndrome problematic in primary care. Dementia is probably under‐diagnosed and under treated with an estimated 50% of primary care patients over 65 not diagnosed by their primary care physicians. This problem of under‐diagnosis is probably not due to lack of diagnostic skills, but rather to the interaction of case‐complexity, pressure on time and the negative effects of reimbursement systems. Primary care physicians often over‐estimate the prevalence of dementia syndromes, but in some countries may also overestimate the prevalence of vascular dementia compared with Alzheimer's disease. Diagnosis is a step‐wise process which can be aided by use of a cognitive function test, of which there are a number suitable for primary care use. Evidence based practice protocols can enhance detection rates in primary care, and there is growing evidence that communication skills in talking to people with dementia about dementia can be improved. Nevertheless there are multiple obstacles to bringing recognition forward in time, both in public awareness and professional understanding of the early changes in dementia.

Conclusions

There is insufficient evidence of benefit to justify population screening in primary care but earlier recognition of people with dementia syndrome is possible within primary care. The diagnosis of dementia is a shared responsibility between generalist and specialist disciplines. Primary care physicians should explore patients' ideas and concerns around their symptoms prior to referral and tentatively discuss possible diagnoses. Once the diagnosis has been confirmed, the primary care physician should provide both practical and emotional support to allow the patient and their family to come to terms with living with dementia, and refer them for additional psychosocial support if required. Copyright © 2009 John Wiley & Sons, Ltd.
The moderating role of personality factors in the relationship between depression and neuropsychological functioning among older adults
Authors: Ayotte Brian J. , Potter Guy G. , Williams Heather T. , Steffens David C. , Bosworth Hayden B.
Published: February 2009

Objective

Depression is often associated with decreased cognitive performance among older adults. The current study focused on the association of neuropsychological functioning and personality traits in depressed and non‐depressed older adults.

Methods

Data from 75 depressed and 103 non‐depressed adults over the age of 60 were analyzed. All participants underwent standardized clinical assessment for depression prior to participation and completed the NEO‐PI‐R and a series of neuropsychological assessments.

Results

A series of multiple linear regressions were conducted to examine the relationships between personality and neuropsychological performance among depressed and non‐depressed older adults. Results indicated that higher Openness to Experience was related to better performance on Parts A and B of the Trail Making Test among depressed older adults, and to better Digit Span Backward performance among all participants. Higher levels of neuroticism were related to poorer performance on Digit Span Backward, but only among depressed older adults. Depressed participants performed more poorly on the Symbol Digit Modalities Test and the Controlled Oral Word Association Test.

Conclusions

Personality characteristics, particularly Openness to Experience, modified the relationship between depression and neuropsychological functioning among older adults. Results indicate that interventions aimed at increasing one's Openness to Experience could potentially attenuate some of the neuropsychological impairments that are associated with depression. Copyright © 2009 John Wiley & Sons, Ltd.
Pharmacological treatment for the prevention of delirium: review of current evidence
Authors: Tabet Naji , Howard Robert
Published: February 2009

Objective

Delirium is a very common and serious disorder with high morbidity and mortality. Despite symptomatic treatment the outcome can be poor for some especially when no underlying cause is identified. As a result, various strategies for delirium prevention have been assessed. Pharmacological agents such as antipsychotics, acetylcholinesterase inhibitors, sleep–wake cycle regulators, anti‐inflammatories and others have been advocated for a potential role in delirium prevention. The aim of this paper is to review the available evidence for their use in the prevention of delirium.

Methods

An electronic search was carried out using Medline, EMBASE and Cochrane for randomised controlled trials (RCTs) and other studies. The words delirium, prevention, intervention, pharmacological, prophylactic, antipsychotics, acetylcholinesterase inhibitors, sleep and anti‐inflammatories were used. References from selected papers were also searched.

Results

No multi‐centre RCT has been identified. Few trials and other studies have been published so far assessing the prophylactic role of antipsychotics, acetylcholinesterase inhibitors, hypnotics, melatonin, and gabapentin. As these studies tested different drugs, regimes and protocols in diverse populations no meaningful comparison can be made.

Conclusion

To date there is conflicting and inconsistent data regarding the efficacy of pharmacological treatment for delirium prevention. Positive reports in few of the studies justify further assessment of the potential for some pharmacological agents in the prevention of delirium. Well designed and appropriately powered RCTs are now needed. However, based on available evidence so far, no recommendation can be made to justify the routine clinical prophylactic use of any pharmacological agent in the prevention of delirium. Copyright © 2009 John Wiley & Sons, Ltd.
PCSK9 impedes hepatitis C virus infection in vitro and modulates liver CD81 expression #
Authors: Labonté Patrick , Begley Syntia , Guévin Carl , Asselin Marie-Claude , Nassoury Nasha , Mayer Gaétan , Prat Annik , Seidah Nabil G.
Published: February 2009

Human PCSK9 is known to enhance the degradation of membrane-bound receptors such as the hepatocyte low-density lipoprotein receptor (LDLR), ApoER2, and very low-density lipoprotein receptor. Because the LDLR is suspected to be involved in hepatitis C virus (HCV) entry, we also tested whether PCSK9 can affect the levels of CD81, a major HCV receptor. Interestingly, stable expression of PCSK9 or a more active membrane-bound form of the protein (PCSK9-ACE2) resulted in a marked reduction in CD81 and LDLR expression. Therefore, we analyzed the antiviral effect of PCSK9 in vitro using the HCV genotype 2a (JFH1) virus. The results clearly demonstrated that cells expressing PCSK9 or PCSK9-ACE2, but not the ACE2 control protein, were resistant to HCV infection. Furthermore, addition of purified soluble PCSK9 to cell culture supernatant impeded HCV infection in a dose-dependent manner. As expected, HuH7 cells expressing PCSK9-ACE2 were also resistant to infection by HCV pseudoparticles. In addition, we showed that CD81 cell surface expression is modulated by PCSK9 in an LDLR-independent manner. Finally, in the liver of single Pcsk9 and double (Pcsk9 + Ldlr) knockout mice, both LDLR and/or CD81 protein expression levels were significantly reduced, but not those of transferrin and scavenger receptor class B type 1. Conclusion: Our results demonstrate an antiviral effect of the circulating liver PCSK9 on HCV in cells and show that PCSK9 down-regulates the level of mouse liver CD81 expression in vivo. Therefore, we propose that the plasma level and/or activity of PCSK9 may modulate HCV infectivity in humans. (Hepatology 2009.)
S6K1 deficiency protects against apoptosis in hepatocytes #
Authors: González-Rodriguez Águeda , Alba Javier , Zimmerman Valeri , Kozma Sara C. , Valverde Ángela M.
Published: February 2009

The mammalian target of rapamycin (mTOR)/S6K1 signaling pathway controls cell growth and proliferation. To assess the importance of S6K1 in the balance between death and survival in the liver, we have generated immortalized hepatocyte cell lines from wild-type and S6K1-deficient (S6K1−/−) mice. In S6K1−/− hepatocytes, caspase-8 and the pro-apoptotic protein Bid were constitutively down-regulated as compared with wild-type. Moreover, S6K1−/− hepatocytes failed to respond to the apoptotic trigger of death receptor activation. Neither caspase-8 activation nor FLIPL degradation in response to tumor necrosis factor alpha (TNF-α) or anti-Fas antibody (Jo2) was observed in cells lacking S6K1. Downstream events such as Bid cleavage, cytochrome C release, caspase-3 activation, DNA laddering, as well as the percentage of apoptotic cells were attenuated as compared with wild-type. In addition, the anti-apoptotic protein BclxL was down-regulated in TNF-α–treated or Jo2-treated wild-type hepatocytes, but this response was abolished in S6K1−/−cells. In vivo, S6K1-deficient mice were protected against concanavalin A–induced apoptosis. The withdrawal of growth factors strongly induced apoptosis in wild-type, but not in S6K1−/− hepatocytes. S6K1 deficiency did not decrease BclxL/Bim ratio on serum withdrawal, thereby protecting cells from cytochrome C release and DNA fragmentation. At the molecular level, the lack of S6K1-mediated negative feedback decreased insulin receptor substrate-1 (IRS-1) serine phosphorylation, resulting in activation of survival pathways mediated by phosphatidylinositol 3-kinase/Akt and extracellular signal-regulated kinase (ERK). However, S6K1−/− hepatocytes underwent apoptosis on serum withdrawal in combination with phosphatidylinositol 3-kinase (PI3K) or ERK inhibitors. Conclusion: This finding might explain the mechanism of resistance to mTOR inhibitors in cancer treatments and strongly suggests that the inhibition of S6K1 could protect against acute liver failure and, in combination with inhibitors that abrogate the sustained activation of Akt and ERK, could improve the efficacy of hepatocarcinoma (HCC) treatment. (Hepatology 2009.)
Fluid flow and heat transfer characteristics of cone orifice jet (effects of cone angle)
Authors: Kito Mizuki , Shakouchi Toshihiko , Tsujimoto Koichi , Ando Toshitake
Published: February 2009

The use of a jet from an orifice nozzle with a saddle‐backed‐shape velocity profile and a contracted flow at the nozzle exit may improve the heat transfer characteristics on an impingement plate because of its larger centerline velocity. However, it requires more power to operate than a common nozzle because of its higher flow resistance. We therefore initially considered the use of a cone orifice nozzle to obtain better heat transfer performance as well as to decrease the flow resistance. We examined the effects of the cone angle α on the cone orifice free jet flow and heat transfer characteristics of the impinging jet. We compared two nozzles: a pipe nozzle and a quadrant nozzle. The first one provides a velocity profile of a fully developed turbulent pipe flow, and the second has a uniform velocity profile at the nozzle exit. We observed a significant enhancement of the heat transfer characteristics of the cone orifice jets at Re=1.5×104. Using the cone orifice impinging jets enhanced the heat transfer rates as compared to the quadrant jet, even when the jets were supplied with the same operational power as the pipe jet. For instance, a maximum enhancement up to approximately 22% at r/do≅0.5 is observed for α=15°. In addition, an increase of approximately 7% is attained as compared to when the pipe jet was used. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20243
Vortex structure behind highly heated two cylinders in parallel arrangements
Authors: Kurita Eiichirou , Yahagi Yuji
Published: February 2009

Vortex structures behind twin, highly heated cylinders in parallel arrangements have been investigated experimentally. The experiments were conducted under the following conditions: cylinder diameter, D=4mm; mean flow velocity, U∞ = 1.0 m/s; Reynolds number, Re=250; cylinder clearance, S/D=0.5 to 1.4; and cylinder heat flux, q=0 to 72.6kW/m2. For S/D>1.2, the Karman vortex street is formed alternately behind each cylinder divided on the slit flow. The slit flow velocity increases with a decrease in S/D and decreases with increasing heat flux. For S/D < 1.2, the wake vortexes become asymmetric having small and large scale vortexes divided by the slit flow. In the small scale vortexes, the symmetric counter‐rotating twin vortexes are formed just behind the cylinders. In the large scale vortexes, the generated vortexes have a similar structure to a Karman vortex even though the Strouhal number is approximately half of the ordinary single cylinder vortex. For isothermal conditions, the transition phenomena from symmetric to asymmetric wake structures are observed in the range of 0.9 < S/D <1.2. In addition, the asymmetric vortexes are irregularly switched up and down in the case of isothermal conditions. In the highly heated condition, the switching phenomena and the transition phenomena could not be observed and the small scale vortexes always formed behind the upper cylinder. The critical S/D increases approximately 30% in the heated condition (q=72.6kW/m2). As a result, the increased local kinematic viscosity and S/D play a key role for the vortex structure and formation behind arrangements of two parallel cylinders. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20244
Season of diagnosis has no effect on survival from malignant melanoma
Authors: Jayasekara Harindra , Karahalios Emily , Thursfield Vicky , Giles Graham G. , English Dallas R.
Published: February 2009

Diagnosis in summer had been shown to be associated with better survival from some cancers, but such studies on malignant melanoma where sun exposure is a risk factor for disease are rare. We evaluated seasonality in melanoma diagnosis and its effect on survival in Victoria, Australia using 26,060 cases reported to the population‐based Victorian Cancer Registry during 1986–2004. To estimate the amplitude of the seasonal variation, we calculated the ratio of the number of melanoma cases diagnosed in summer to that in winter. Linear regression was undertaken to assess the variation in thickness, the main prognostic indicator for melanoma, by season of diagnosis adjusting for sex, anatomical site, year of diagnosis and age at diagnosis. We modeled excess mortality using Poisson regression controlling for possible confounders in order to study the effect of season of diagnosis on survival. An overall 46% summer diagnostic excess was evident (summer‐to‐winter ratio 1.46; 95% CI 1.41, 1.52). Results of linear regression showed that melanoma diagnosed in winter were thicker than those diagnosed in any other season (percentage difference in thickness −2.01, −6.97 and −10.68 for spring, summer and autumn, respectively; p < 0.001). In the Poisson regression model of relative survival, cases diagnosed in spring, summer or autumn had slightly lower excess mortality than those diagnosed in winter before adjustment for other variables, but after adjustment the excess mortality ratios were close to unity. Our findings do not support the hypothesis that melanoma cases diagnosed in winter have worse prognosis than cases diagnosed in other seasons. © 2009 UICC
Functional analysis of the ‐2548G/A leptin gene polymorphism in breast cancer cells
Authors: Terrasi Marianna , Fiorio Elena , Mercanti Anna , Koda Mariusz , Moncada Camilo A. , Sulkowski Stanislaw , Merali Salim , Russo Antonio , Surmacz Eva
Published: February 2009

Leptin is overexpressed in human breast tumors and is produced by breast cancer cells in response to obesity‐related stimuli. The leptin promoter polymorphism Lep‐2548G/A can be associated with increased leptin secretion by adipocytes and elevated cancer risk. However, molecular mechanisms underlying the link between Lep‐2548G/A and breast cancer have never been addressed. Lep‐2548G/A is proximal to a binding site for the transcriptional factor Sp1. Furthermore nucleolin, a transcriptional repressor, can bind Sp1 or its consensus site. Consequently, we focused on the impact of Lep‐2548G/A on Sp1‐ and nucleolin‐dependent leptin transcription in breast cancer cells. The Lep‐2548G/A was identified in a homozygous conformation in BT‐474 and SK‐BR‐3 breast cancer cells, in a heterozygous conformation in MDA‐MB‐231 cells, and a wild‐type Lep‐2548G/G sequence was present in MCF‐7 and ZR‐75‐1 cells. The occurrence of Lep‐2548A/A and Lep‐2548G/A coincided with high and intermediate leptin mRNA expression, respectively, while cells containing Lep‐2548G/G expressed low leptin mRNA levels. We demonstrated that the existence of Lep‐2548G/A improved efficient recruitment of Sp1 to DNA under insulin treatment, while Sp1 loading on DNA containing Lep‐2548G/G was not insulin‐dependent. In contrast, nucleolin binding to Lep‐2548G/A was downregulated in response to insulin, while it was not regulated on Lep‐2548G/G. The presence of Lep‐2548G/A was studied in breast cancer epithelial cells by IHC and LCM. Interestingly, all 14 tumors expressing high leptin levels contained Lep‐2548A/A. In conclusion, the occurrence of Lep‐2548G/A can enhance leptin expression in breast cancer cells via Sp1‐ and nucleolin‐dependent mechanisms and possibly contribute to intratumoral leptin overexpression. © 2009 UICC
Essential role of Notch signaling in apoptosis of human pancreatic tumoral cells mediated by exosomal nanoparticles
Authors: Ristorcelli Elodie , Beraud Evelyne , Mathieu Sylvie , Lombardo Dominique , Verine Alain
Published: February 2009

We previously reported that exosomal nanoparticles secreted by human pancreatic tumoral cell lines decrease tumoral cell proliferation through the mitochondria‐dependent apoptotic pathway, because of activation of pro‐apoptotic phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and of glucose synthase kinase‐3β (GSK‐3β). Interactions between exosomal nanoparticles and cells are thought to involve membrane lipid rafts. However, the underlying mechanism is unknown. Here, we report that the interaction of exosomal nanoparticles with pancreatic cancer cells led to decreased expression of hairy and enhancer‐of‐split homolog‐1 (Hes‐1), the intranuclear target of Notch‐1 signaling pathway, and to activation of the apoptotic pathway after a cell cycle arrest in G0G1 phase. Strikingly, the expression level of Notch‐1 pathway components was critical, because exosomal nanoparticles decreased the proliferation of cells in which these partners are either weakly represented, in differentiated adenocarcinoma cells, or inhibited, in poorly differentiated carcinoma cells, by blocking presenilin in the γ‐secretase complex that regulates the Notch‐1 pathway. Overexpression of Notch‐1 intracellular domain resulted in the reversion of the cell proliferation inhibition promoted by exosomal nanoparticles. Blocking presenilin unexpectedly resulted in activation of PTEN and GSK‐3β. Conversely, inhibiting either PTEN or GSK‐3β increased Hes‐1 expression and partially counteracted the inhibition of proliferation promoted by exosomal nanoparticles, highlighting reciprocal regulations between Notch signaling and PTEN/GSK‐3β. We concluded that interactions of exosomal nanoparticles with target cells, at lipid rafts where Notch‐1 pathway partners are localized, hampered the functioning of the Notch‐1 survival pathway and activated the apoptotic pathway, which determines tumoral cell fate. © 2009 UICC
Stromal MCP‐1 in mammary tumors induces tumor‐associated macrophage infiltration and contributes to tumor progression
Authors: Fujimoto Hiroshi , Sangai Takafumi , Ishii Genichiro , Ikehara Akashi , Nagashima Takeshi , Miyazaki Masaru , Ochiai Atsushi
Published: February 2009

There is growing evidence that tumor‐associated macrophages (TAMs) promote tumor growth and dissemination. Many individual reports have focused on the protumor function of molecules linked to the recruitment of macrophages, but little is known about which factor has the strongest impact on recruitment of macrophages in breast cancer. To elucidate this question, we performed RT‐PCR using species‐specific primers and evaluated tumoral and stromal mRNA expression of macrophage chemoattractants separately in human breast tumor xenografts. The correlation between the tumoral or stromal chemoattractant mRNA expression including monocyte chemoattractant protein‐1 (MCP‐1) (CCL2), MIP‐1α (CCL3), RANTES (CCL5), colony‐stimulating factor 1, tumor necrosis factor α, platelet‐derived growth factor (PDGF)‐BB and macrophage infiltration were compared. There was significant positive correlation between stromal MCP‐1 expression and macrophage number (r = 0.63), and negative correlation between tumoral RANTES expression and macrophage number (r = −0.75). However, no significant correlation was found for the other tumoral and stromal factors. The interaction between the tumor cells and macrophages was also investigated. Tumor cell–macrophage interactions augmented macrophage‐derived MCP‐1 mRNA expression and macrophage chemotactic activity in vitro. Treatment of immunodeficient mice bearing human breast cancer cells with a neutralizing antibody to MCP‐1 resulted in significant decrease of macrophage infiltration, angiogenetic activity and tumor growth. Furthermore, immunohistochemical analysis of human breast cancer tissue showed stromal MCP‐1 had a significant correlation with relapse free survival (p = 0.029), but tumoral MCP‐1 did not (p = 0.105). These findings indicate that stromal MCP‐1 produced as a result of tumor–stromal interactions may be important for the progression of human breast cancer and macrophages may play an important role in this tumor–stroma interaction. © 2009 UICC.
Conducting suicide research in naturalistic clinical settings
Authors: Jobes David A. , Bryan Craig J. , Neal‐Walden Tracy A.
Published: February 2009

Unique challenges arise for clinical researchers designing studies focused on suicidal behaviors due to the inherently high‐risk nature of such research. Traditional approaches to clinical trial design are briefly discussed, highlighting the limitations and obstacles of these approaches when working with suicidal individuals. Using their own personal experiences and setbacks from an ongoing clinical suicidology research program, the authors argue for greater emphasis on effectiveness and translational research designs conducted in naturalistic clinical settings to test the practical utility of empirically‐supported treatments for suicidal behaviors, to gain new perspectives on suicidal individuals, and to better understand the nature of suicidal risk. © 2009 Wiley Periodicals, Inc. J Clin Psychol 65:1–14, 2009.
Discharge variability for an artesian spring of the Edwards Aquifer: Comal Springs (1933–2007)
Authors: Cox Walter D. , Meng Lei , Khedun C. Prakash , Nordfelt Anna , Quiring Steven M.
Published: February 2009

Daily discharge volumes of Comal Springs, the largest artesian spring of the Edwards Aquifer (EA) in Central Texas, were utilized to characterize the flow of Comal Springs for the period of record spanning 1933–2007. The influence of water extraction (pumping) on discharge characteristics during the record was examined and found to be statistically significant for both volume and variability of spring discharge (p < 0.01). Pumping explains approximately a quarter of the variation in annual discharge (r2 = 0.25) and nearly a third of the daily variability (r2 = 0.32) within the Comal Springs discharge record.

Statistically significant teleconnections to flow are demonstrated within the discharge record of Comal Springs. The El Niño‐Southern Oscillation (ENSO, as measured by the Southern Oscillation Index) and the Pacific Decadal Oscillation (PDO) are shown to exhibit statistically significant correlations with annual mean flow from Comal Springs. PDO modulation of ENSO results in mean flow anomalies of 21.9% between extreme quintile years. The Atlantic Multi‐decadal Oscillation (AMO) appears to exert influence based on the magnitude of the index value, irrespective of its positive or negative condition (p < 0.01), with the highest quintile (based on magnitude) years correlating with strong positive flow anomalies. A composite index was developed which combines the AMO, PDO and SOI. The extreme quintile years of this index demonstrate a 32.4% divergence in flow (p < 0.01) while demonstrating a stronger skill at capturing negative flow anomalies than positive anomalies.

Precipitation data, at 4‐km spatial resolution, were utilized to examine the temporal and spatial correlation of water input to the EA with rates of average monthly discharge from Comal Springs. The spatial dependence of the correlation between precipitation and Comal Springs discharge indicates significant seasonal variability. Overall, the correlation between precipitation and discharge is significant for spring, summer and fall seasons and not significant for winter. Copyright © 2009 Royal Meteorological Society
Analysis of anaesthetics and analgesics in human urine by headspace SPME and GC
Authors: Raikos Nikolaos , Theodoridis Georgios , Alexiadou Efi , Gika Helen , Argiriadou Helena , Parlapani Heleni , Tsoukali Heleni
Published: February 2009

The determination of widely used anaesthetic and analgesic drugs in biological fluids is of major clinical importance. Typical methods used for sample preparation employ liquid–liquid extraction protocols which are complex, costly, not handy and not amenable to automation. In the present communication, we report the development of a methodology that employs headspace solid‐phase microextraction (HS‐SPME) for the determination of four anaesthetic (lidocaine, midazolam, diazepam and ketamine) and three analgesic drugs (fentanyl, remifentanyl and codeine) in human urine. Important parameters controlling SPME were studied: selection of SPME fibre, type and amount of salt added, preheating and extraction time, extraction temperature, sample volume and desorption time. GC with nitrogen phosphorus detection (GC‐NPD) facilitates sensitive and selective detection of the anaesthetics. The developed method renders an efficient tool for the precise and sensitive determination of the anaesthetics and analgesics in human urine (RSDs ranged from 7.7 to 12.6%, whereas LODs ranged from 0.01 to 1.5 ng/mL). The method was applied to the determination of the anaesthetics and analgesics in human urine from patients that had undergone coronary by‐pass surgery operations. The proposed protocol can function as an attractive alternative for clinical acute intoxications and medico‐legal cases.