bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Exciton Quenching by Hole Polarons in the Conjugated Polymer MEH‐PPV
Authors: Yu Ji , Song Nam Woong , Mcneill Jason D. , Barbara Paul F.
Published: November 2004

Recently published near field scanning optical measurements (NSOM) on the conjugated polymer MEH‐PPV exhibited a strong dependence of the photoluminescence intensity on the applied electric fields at the NSOM tip. The observed effect is apparently due to exciton quenching by hole polarons. In the present paper, a model “single carrier” electro‐modulated‐photoluminescence device is used to further explore the exciton quenching effect of hole polarons in MEH‐PPV. Hole polarons, created by charge injection from an ITO electrode, are observed to dramatically quench the photoluminescence intensity of MEH‐PPV. The Stern‐Volmer quenching efficiency of a hole polaron in conjugated polymer thin films was measured to be 390 nm3. This value, and other data presented herein, are consistent with the published NSOM photoluminescence modulation measurements and offer further evidence that hole polarons are efficient photoluminescence quenchers in MEH‐PPV.
Physicochemical Methods for Prediction of Functional Information for Proteins
Authors: Murga Leonel F. , Wei Ying , André Pierrette , Clifton James G. , Ringe Dagmar , Jo Ondrechen Mary
Published: November 2004

Structural genomics initiatives are determining thousands of new protein structures. Many of these structures are of unknown function, and computational methods for the rapid determination of functional information from protein structure are needed. We present details of how functional information is obtained from the structure using THEMATICS (Theoretical Microscopic Titration Curves). THEMATICS is a computational procedure that gives information about chemical reactivity, based on solution of the Poisson‐Boltzmann equations for the electrical potential function. We show how anomalies in predicted titration curves are established. We show further that when residues with anomalous predicted titration curves form a cluster in physical space, these residues tend to be very highly conserved across species and such clusters are reliable predictors of the active site. Results are given for ten enzymes; detailed results are shown for the enzymes triosephosphate isomerase (from chicken), 6‐hydroxymethyl‐7,8‐dihydropterin pyrophosphokinase (from E. coli), and papain (from papaya).
Pump‐Probe Spectroscopy of Population Wave Packets with Intense Chirped Pulses
Authors: Segal Jonathan , Huppert Dan , Fainberg Boris D.
Published: November 2004

We have studied the time evolution of population wave packets under intense chirped pulse excitation by resonance heterodyne optical Kerr effect spectroscopy. In general, this method enables us to obtain complementary information about population wave packets versus the absorption spectrum of an intense chirped pulse. We have generalized the “moving potentials” picture of one of the authors to a non‐Debye solvent. We analyze the effects of both the parameters of the solvent‐solute system and the electric field on the signal of the heterodyne optical Kerr effect experiment.
Submillimeter‐scale combustion
Authors: Miesse Craig M. , Masel Richard I. , Jensen Craig D. , Shannon Mark A. , Short Mark
Published: November 2004

Until recently, the concept of combustion within a confined space defined by a microburner was thought to be impossible. Extensive literature dating back to Davy's seminal work in 1817 has discussed how thermal and chemical quenching set a minimum size below which no flame can exist. In this report, though, it is shown that microcombustion is possible if the wall composition and structure are carefully controlled. It is suggested that there are three keys to obtaining microcombustion: (1) the walls of the microburner need to be fabricated from materials that do not quench radicals so that the gas‐phase combustion reactions can occur unimpeded; (2) the device needs to be insulated well enough that the net heat generation is sufficient to keep the reacting mixture hot enough to sustain significant combustion; and (3) the flow pattern in the burner needs to be such that the temperature is low enough not to melt the walls, yet the flame fills the entire space. Using this design strategy, devices burning methane–air and propane–air mixtures in a 750‐μm slot were designed and optimized to achieve high conversion. These results show that microcombustion is possible with consideration of microscale engineering challenges and fitting combustor design. © 2004 American Institute of Chemical Engineers AIChE J, 50: 3206–3214, 2004
Monodispersed microbubble formation using microchannel technique
Authors: Yasuno Motohiro , Sugiura Shinji , Iwamoto Satoshi , Nakajima Mitsutoshi , Shono Atsushi , Satoh Kazumi
Published: November 2004

Recently, we proposed microchannel (MC) emulsification, a novel method for making monodispersed emulsion with a coefficient of variation (CV) less than 5%. In this study, we attempted monodispersed microbubble formation using the MC technique. Monodispersed microbubbles were formed using surfactants and proteins as dispersing agent. The average bubble size ranged from 33.6 to 51.1 μm, and CV values were below 10%. The bubble formation behavior was compared with the droplet formation behavior. The microbubble formation appears to be based on the spontaneous transformation caused by surface tension, as previously shown for liquid–liquid systems. The average bubble size was affected by viscosity, which is consistent with the results for the liquid–liquid system in previous studies. In the case of protein, the effect of surface viscoelasticity was indicated, which was not reported for the liquid–liquid system. © 2004 American Institute of Chemical Engineers AIChE J, 50: 3227–3233, 2004
Combined experimental/numerical study on the precipitation of nanoparticles
Authors: Schwarzer Hans‐Christoph , Peukert Wolfgang
Published: November 2004

Nanoparticle precipitation in a T‐mixer was investigated experimentally as well as through simulations based on the population balance equation coupled with a global mixing model using barium sulfate as the substance under investigation. A detailed predictive precipitation model is presented and the important model parameters are identified: the mixing kinetics, the interfacial energy, and the physicochemical calculation of supersaturation. Furthermore, the capability of the global mixing model was evaluated, achieving good agreement of the mean particle sizes between experimental and simulation results. Many insights into the kinetics and the relevant time scales of the competing steps such as micromixing (mixing at the molecular level), nucleation, growth, and aggregation are obtained. However, some discrepancies in the width of the particle size distributions remain that are attributed to spatial and temporal fluctuations in the flow field and, consequently, in the mixing kinetics that cannot be resolved by the applied global mixing model. © 2004 American Institute of Chemical Engineers AIChE J, 50: 3234–3247, 2004
The total median in statistical quality control
Authors: Figueiredo Fernanda , Gomes M. Ivette
Published: November 2004

In industry, most of the process observations are assumed to come from a normal population, but usually we merely want to control the process mean value. It is thus sensible to find control statistics, which are ‘robust’ to monitor the process mean, giving the expected rate of false alarms whenever that mean is close to the target value, although not under a normal regime. Simulation studies for a few symmetric and asymmetric distributions allow us to suggest the total median as a robust median estimator. We shall here analyse such a robustness, as well as the robustness of the total median chart comparatively to the sample mean chart, whenever we want to control the mean value of a symmetric underlying parent. Some indication is also provided on the comparative out‐of‐control behaviour of the two charts. Copyright © 2004 John Wiley & Sons, Ltd.
Periconceptional multivitamin intake during early pregnancy, genetic variation of acetyl‐N‐transferase 1 (NAT1), and risk for orofacial clefts
Authors: Lammer Edward J. , Shaw Gary M. , Iovannisci David M. , Finnell Richard H.
Published: November 2004

BACKGROUND

Periconceptional supplementation of multivitamins that include folic acid have been shown to prevent several birth defects, including neural tube defects and orofacial clefts. We investigated whether polymorphic variants of fetal acetyl‐N‐transferase 1 (NAT1), an enzyme involved in the catabolism of folates, differentially interacted with maternal multivitamin use during early pregnancy to alter the risk of delivering an infant with an orofacial cleft malformation.

METHODS

Using a large population‐based case‐control study, we genotyped 421 California infants born with an isolated cleft and 299 controls for two NAT1 polymorphisms.

RESULTS

Compared to the homozygous wild‐type genotypes, odds ratios for isolated cleft lip with/without cleft palate were slightly increased among infants who were homozygous for the variant alleles of NAT1 1088 and 1095. For isolated cleft palate, no similar associations with these two NAT1 variants were observed. For NAT1 1088 genotypes, we did not observe any differential risks for clefts related to maternal multivitamin intake. For NAT1 1095 genotypes, however, we found a two‐fold higher risk for isolated cleft lip with/without cleft palate among infants who were homozygous for the variant allele and whose mothers did not take multivitamins during early pregnancy.

CONCLUSIONS

We found evidence suggestive of an interaction between the NAT1 1095 polymorphism and lack of maternal multivitamin use that increased risks of isolated cleft lip with/without cleft palate. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Towards gelsolin amyloid formation
Authors: Liepina Inta , Janmey Paul , Czaplewski Cezary , Liwo Adam
Published: November 2004

Amyloid diseases result from protein misfolding and aggregation into fibrils. Some features of gelsolin amyloidogenic fragments comprised of residues 173–243 (G173–243) and residues 173–202 (G173–202) were investigated by the method of molecular dynamics (MD). The α‐helical structure of G173–243 present in the whole protein unwinds during the course of MD simulation of the fragment G173–243, suggesting that the G173–243 structure is not stable and could unfold before becoming involved in gelsolin amyloid fibril formation. Twelve fragments of G173–202 were used to build a possible β‐fibril. During the course of the simulation, G173–202 fragments formed hydrogen bonds and tended to turn by an angle of 10°–20° towards each other. © 2004 Wiley Periodicals, Inc. Biopolymers (Pept Sci), 2004
Nitration of Alkanes with Nitric Acid by Vanadium‐Substituted Polyoxometalates
Authors: Shinachi Satoshi , Yahiro Hidenori , Yamaguchi Kazuya , Mizuno Noritaka
Published: November 2004

The nitration of alkanes by using nitric acid as a nitrating agent in acetic acid was efficiently promoted by vanadium‐substituted Keggin‐type phosphomolybdates such as [H4PVMo11O40], [H5PV2Mo10O40], and [H6PV3Mo9O40] as catalyst precursors. A variety of alkanes including alkylbenzenes were nitrated to the corresponding nitroalkanes as major products in moderate yields with formation of oxygenated products under mild reaction conditions. The carboncarbon bond cleavage reactions hardly proceeded. ESR, NMR, and IR spectroscopic data show that the vanadium‐substituted polyoxometalate, for example, [H4PVMo11O40], decomposes to form free vanadium species and [PMo12O40]3− Keggin anion. The reaction mechanism involving a radical‐chain path is proposed. The polyoxometalates initially abstract the hydrogen of the alkane to form the alkyl radical and the reduced polyoxometalates. The reduced polyoxometalates subsequently react with nitric acid to produce the oxidized form and nitrogen dioxide. This step would be promoted mainly by the phosphomolybdates, [PMo12O40]n−, and the vanadium cations efficiently enhance the activity. The nitrogen dioxide promotes the further formation of nitrogen dioxide and an alkyl radical. The alkyl radical is trapped by nitrogen dioxide to form the corresponding nitroalkane.
Convergent Synthesis of Platinum–Acetylide Dendrimers
Authors: Onitsuka Kiyotaka , Fujimoto Masanori , Kitajima Hotaka , Ohshiro Nobuaki , Takei Fumie , Takahashi Shigetoshi
Published: November 2004

An efficient convergent route to the main chain type of organometallic dendrimers, in which platinum moieties are linked by 1,3,5‐triethynylbenzene, has been developed. The synthesis of platinum–acetylide dendrons involved the use of two types of trialkylsilyl groups for protection of the terminal acetylene. The platinum–acetylide dendrimers were prepared up to the third generation by reacting dendrons with a triplatinum core and a tetraplatinum core. Spectroscopic characterization and trace experiments by gel permeation chromatography indicated that the dendrimer molecules have no structural defects. Although a π‐conjugated system was used as the bridging ligand, electronic and fluorescence spectra suggested that the interaction among the platinum–acetylide moieties in the dendrimers was small.
Chiral Molecular Glass: Synthesis and Characterization of Enantiomerically Pure Thiophene‐Based [7]Helicene
Authors: Miyasaka Makoto , Rajca Andrzej , Pink Maren , Rajca Suchada
Published: November 2004

Synthesis of thiophene‐based [7]helicenes, which are functionalized for both design of organic chiral glasses with strong chiroptical properties and for further homologation to higher [n]helicenes, is reported. The key synthetic transformations are kinetic resolution of the intermediate diketone and the annelation step forming the center benzene ring by means of an intramolecular McMurry reaction. Based upon X‐ray crystallographic determinations of the absolute configurations for (+)‐enantiomers of the diketone and the [7]helicene, stereochemical correlation between the (R) axial chirality of the diketone and the (M) helical chirality of the [7]helicene is established. One such enantiopure trimethylsilyl‐substituted [7]helicene possesses enchanced chiroptical properties and forms a chiral molecular glass.
Titanium(IV) and Zirconium(IV) Sulfato Complexes Containing the Kläui Tripodal Ligand: Molecular Models of Sulfated Metal Oxide Surfaces
Authors: Zhang Qian‐Feng , Lam Tony C. H. , Yi Xiao‐Yi , Chan Eddie Y. Y. , Wong Wai‐Yeung , Sung Herman H. Y. , Williams Ian D. , Leung Wa‐Hung
Published: November 2004

Treatment of titanyl sulfate in about 60 mM sulfuric acid with NaLOEt (LOEt−=[(η5‐C5H5)Co{P(O)(OEt)2}3]−) afforded the μ‐sulfato complex [(LOEtTi)2(μ‐O)2(μ‐SO4)] (2). In more concentrated sulfuric acid (>1 M), the same reaction yielded the di‐μ‐sulfato complex [(LOEtTi)2(μ‐O)(μ‐SO4)2] (3). Reaction of 2 with HOTf (OTf=triflate, CF3SO3) gave the tris(triflato) complex [LOEtTi(OTf)3] (4), whereas treatment of 2 with Ag(OTf) in CH2Cl2 afforded the sulfato‐capped trinuclear complex [{(LOEt)3Ti3(μ‐O)3}(μ3‐SO4){Ag(OTf)}][OTf] (5), in which the Ag(OTf) moiety binds to a μ‐oxo group in the Ti3(μ‐O)3 core. Reaction of 2 in H2O with Ba(NO3)2 afforded the tetranuclear complex (LOEt)4Ti4(μ‐O)6 (6). Treatment of 2 with [{Rh(cod)Cl}2] (cod=1,5‐cyclooctadiene), [Re(CO)5Cl], and [Ru(tBu2bpy)(PPh3)2Cl2] (tBu2bpy=4,4′‐di‐tert‐butyl‐2,2′‐dipyridyl) in the presence of Ag(OTf) afforded the heterometallic complexes [(LOEt)2Ti2(O)2(SO4){Rh(cod)}2][OTf]2 (7), [(LOEt)2Ti(O)2(SO4){Re(CO)3}][OTf] (8), and [{(LOEt)2Ti2(μ‐O)}(μ3‐SO4)(μ‐O)2{Ru(PPh3)(tBu2bpy)}][OTf]2 (9), respectively. Complex 9 is paramagnetic with a measured magnetic moment of about 2.4 μB. Treatment of zirconyl nitrate with NaLOEt in 3.5 M sulfuric acid afforded [(LOEt)2Zr(NO3)][LOEtZr(SO4)(NO3)] (10). Reaction of ZrCl4 in 1.8 M sulfuric acid with NaLOEt in the presence Na2SO4 gave the μ‐sulfato‐bridged complex [LOEtZr(SO4)(H2O)]2(μ‐SO4) (11). Treatment of 11 with triflic acid afforded [(LOEt)2Zr][OTf]2 (12), whereas reaction of 11 with Ag(OTf) afforded a mixture of 12 and trinuclear [{LOEtZr(SO4)(H2O)}3(μ3‐SO4)][OTf] (13). The ZrIV triflato complex [LOEtZr(OTf)3] (14) was prepared by reaction of LOEtZrF3 with Me3SiOTf. Complexes 4 and 14 can catalyze the Diels–Alder reaction of 1,3‐cyclohexadiene with acrolein in good selectivity. Complexes 2–5, 9–11, and 13 have been characterized by X‐ray crystallography.
Fine‐needle aspiration of primary and recurrent benign fibrous histiocytoma: Classic, aneurysmal, and myxoid variants
Authors: Klijanienko Jerzy , Caillaud Jean‐Michel , Lagacé Réal
Published: November 2004

There is a limited number of correlative cytopathological studies of fibrous histiocytoma (FHC). To better define cytopathological criteria of diagnosis, we have reviewed fine‐needle aspirates (FNA) from 36 FHCs (32 classical, 1 myxoid, and 3 aneurysmal variants on corresponding histological sections).

Original cytological diagnoses were benign in 33 (91.7%) cases (22 accurate) and false positive in 3 (8.3%) cases. All smears were surprisingly homogenous and composed of histiocytic cells with finely vacuolated cytoplasm in 27 (75%) cases, small regular spindle cells in 25 (69%) cases, and giant cells in 17 (47%) cases. Histiocytic cells were attached to vascular structures in 9 (25%) cases. Slight cytonuclear atypia was seen in five (14%) cases. Three (8.3%) cases showed numerous siderophages. In two (5.6%) cases, there were abundant inflammatory backgrounds and in one (3%) case there was a scant myxoid background. Storiform patterns, round cells, prominent atypia, necroses, or mitotic figures were not seen.

FHC should be differentiated from other benign, low‐ and intermediate‐grade spindle‐cell neoplasms such as low‐grade fibrosarcoma, dermatofibrosarcoma protuberans, nodular fasciitis, spindle‐cell malignant melanoma, and monophasic synovial sarcoma. Some cases may be misinterpreted as malignant, especially in cases of recurrence or in patients with a cancer history. Diagn. Cytopathol. 2004;31:387–391. © 2004 Wiley‐Liss, Inc.
A target detection algorithm using polarimetric notch filter
Authors: Suwa Kei , Yamamoto Kazuhiko , Nonaka Chikafusa , Imamura Akihito , Kirimoto Tetsuo
Published: November 2004

When vehicles and ships are observed by radar, echoes from the target are buried in the echoes (clutter) from the ground and the sea surface in the background and detection becomes difficult. Previously, a method known as a Polarimetric Whitening Filter (PWF) was proposed as a target detection technique that focuses on the difference in the polarizations of the clutter and the target and verified its effectiveness. In addition, the authors proposed the Polarimetric Notch Filter (PNF) as a clutter suppression scheme in an environment with a low signal‐to‐clutter power ratio (SCR) and verified the achievement of superior improvement in the SCR performance. In this paper, we propose a target detection algorithm that obtains a constant probability of false alarm by whitening the polarization characteristic of the residual clutter power after suppressing the clutter power by the PNF. From the results of evaluations by computer simulation, we see that the SCR improvement factor of the proposed method was on average about 1.5 dB better than conventional PWF, but the target detection probability was nearly identical. In addition, the results of the performance evaluation of the polarization data of the noise of asphalt and vehicles acquired by polarimetric FMCW radar in the 95‐GHz band where the SCR improvement factors of PNF and PWF were 7.44 and 5.85 dB, respectively, and the SCR improvement factor of PNF was 1.59 dB better. Although the target detection probability was somewhat higher for PNF than PWF, they were nearly identical. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(3): 33–43, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20158
Ideological beliefs as determinants of discrimination in positive and negative outcome distributions
Authors: Amiot Catherine E. , Bourhis Richard Y.
Published: November 2004

Social identity theory proposes that discrimination contributes favourably to group members' social identity. In minimal group paradigm (MGP) studies involving positive outcome distributions (e.g. money), discrimination is associated with a more positive social identity. But studies on the positive‐negative asymmetry effect show that categorization leads to less discrimination when negative (salary cuts) than when positive outcomes (salary increases) are distributed. Using structural equation modelling, this study (N = 279) tested whether discrimination involving negative outcome distributions could contribute as much to group members' positive social identity as discrimination on positive outcomes. The study also tested if ideological beliefs (i.e. social dominance orientation, authoritarianism), measured one month before the MGP experiment, could predict positive and negative outcome discrimination. While the fit of the hypothesized model was adequate, only social dominance orientation predicted both positive and negative outcome discrimination. Also, discrimination on positive outcomes but not on negative ones contributed to positive social identity. Copyright © 2004 John Wiley & Sons, Ltd.
Genetic polymorphism of drug‐metabolizing enzymes and styrene‐induced DNA damage
Authors: Buschini Annamaria , De Palma Giuseppe , Poli Paola , Martino Anna , Rossi Carlo , Mozzoni Paola , Scotti Eleonora , Buzio Luca , Bergamaschi Enrico , Mutti Antonio
Published: November 2004

A cross‐sectional study was carried out on 48 workers exposed to styrene and 14 unexposed healthy controls in order to investigate the genotoxic potential of styrene exposure. DNA damage was assessed in peripheral blood leukocytes (WBCs) by the comet assay. Polymorphisms in glutathione S‐transferase genes (GSTM1, GSTT1, GSTP1) and the gene encoding microsomal epoxide hydrolase (EPHX) were characterized to assess their possible modifying role in styrene metabolism and subsequent DNA damage. Exposed workers showed significantly higher levels of DNA damage compared to controls. Among workers, the GSTM1 and GSTT1 polymorphisms significantly affected comet parameters. Subjects bearing a GSTM1pos genotype showed a significantly higher proportion of damaged nuclei compared to people lacking GSTM1‐1 expression (GSTM1null), whereas GSTT1pos workers showed significantly lower DNA damage than GSTT1null individuals. Styrene‐7,8‐oxide (SO)‐induced DNA damage was assessed in vitro in WBCs isolated from the healthy controls. A clear dose–response relationship at micromolar doses of SO was found for the whole group. WBCs collected from subjects bearing the homozygous wildtype GSTP1 genotype showed a significant protection compared to cells from subjects bearing at least one GSTP1 variant allele. The field survey confirms that styrene exposure is associated with increased DNA damage and indicates a modulating role for GSTM1 and GSTT1 genotypes. In vitro experiments suggest that the extent of SO‐induced DNA strand breaks depends, at least in part, on interindividual differences in GSH‐conjugation capabilities. Environ. Mol. Mutagen. 41:243–252, 2003. © 2003 Wiley‐Liss, Inc.
Detection of ghost cells in the standard alkaline comet assay is not a good measure of apoptosis
Authors: Meintières Sophie , Nesslany Fabrice , Pallardy Marc , Marzin Daniel
Published: November 2004

The single cell gel electrophoresis assay, or Comet assay, is a powerful tool for measurement of DNA strands breaks, oxidative damage, and alkali labile sites, and the assay was recently modified to detect DNA cross‐links. It has also been proposed as a measure of apoptosis since apoptotic cells are suspected to result in total migration of the DNA from the nucleus into the tail. Cells with this appearance are called ghost cells, clouds, hedgehogs, or NDCN (nondetectable cell nuclei). The aim of this study was to determine if ghost cells can be used to measure apoptosis in the standard alkaline comet assay. To answer this question, we made use of two cell lines: CTLL‐2 cells that can enter apoptosis upon addition of apoptosis stimuli or IL‐2 deprivation, and CTLL‐2 bcl2 cells that are protected from apoptosis due to the overexpression of the apoptosis inhibitor gene bcl2. The two cell lines were treated with cytotoxins (nongenotoxic apoptosis inducers, nongenotoxic necrotic agents) or genotoxins. They were also subjected to growth factor withdrawal, which induced apoptosis in the CTLL‐2 cell line. The level of apoptosis was measured by the Annexin V‐FITC method in parallel with performing the Comet assay. The results obtained in the two cell lines suggest that apoptotic or necrotic death does not correlate well with the detection of ghost cells, presumably because these cells are lost upon electrophoresis. A variant of the alkaline Comet assay that was performed without electrophoresis (halo method) was able to efficiently detect cells undergoing apoptosis, but it was unable to clearly distinguish between apoptosis and genotoxic damage. Environ. Mol. Mutagen. 41:260–269, 2003. © 2003 Wiley‐Liss, Inc.
Fine mapping of chromosome 10q deletions in mycosis fungoides and sezary syndrome: Identification of two discrete regions of deletion at 10q23.33–24.1 and 10q24.33–25.1
Authors: Wain E. Mary , Mitchell Tracey J. , Russell‐Jones Robin , Whittaker Sean J.
Published: November 2004

Previous cytogenetic studies in mycosis fungoides (MF) and Sezary syndrome (SS) have identified a large and poorly defined area of chromosomal deletion on chromosome 10q. We report an extensive fine‐mapping allelotyping study using 19 microsatellite markers in the region 10q22.3–10q26.13. Allelic loss was identified by loss of heterozygosity analysis in 26 of 60 (43%) cases: 15 of 45 (33%) with MF and 11 of 15 (73%) with SS. MF and SS samples showed similar patterns of allelic loss with the identification of two discrete regions of deletion which were mutually exclusive in all but two cases. Within the first region of deletion at 10q23.33–10q24.1, around microsatellite marker D10S185 (2.77 Mb), 23 genes were identified, including three (KIF11, HHEX, and HELLS) with functions that, if dysregulated, could be critical in MF and SS. The second region of deletion, 10q24.33–10q25.1, around microsatellite marker D10S530 (3.92 Mb), encodes 11 genes, the majority of which have poorly identified functions. This extensive allelotyping study provides the basis for future highly selective candidate gene analyses. © 2004 Wiley‐Liss, Inc.
Hepatocyte proliferation induced in rats by lead nitrate is suppressed by several tumor necrosis factor α inhibitors
Authors: Kubo Y , Yasunaga M , Masuhara M , Terai S , Nakamura T , Okita K
Published: November 2004

Lead nitrate induces liver cell proliferation in rats without accompanying liver cell necrosis. However, the mechanism of this proliferation and its effect on hepatocytes remain unknown. Therefore, we examined the liver and blood level of hepatocyte growth factor and tumor necrosis factor α (TNF-α) at various intervals to determine whether lead nitrate modifies hepatocyte proliferation by altering the production of these cytokines. We also administered several TNF-α inhibitors, dexamethasone, adenosine, (2E)-3-[5-(2,3- dimethoxy-6-methyl-1,4-benzoquinoyl)]-2-nonyl-2-propenoic acid (E 3330), and pentoxifylline, to rats to clarify whether pretreatment with these inhibitors suppresses the increase of TNF-α messenger RNA (mRNA) in the liver and prevents the hepatocyte proliferation induced by lead nitrate. Hepatocyte proliferation occurred by 24 hours and reached a peak 48 hours after a single intravenous injection of lead nitrate (100 mumol/kg). TNF-α mRNA expression in the liver was increased 1, 6, and 12 hours after the injection, whereas no alteration was observed in liver or blood level of hepatocyte growth factor. Pretreatment with dexamethasone (4.0 mg/kg), E3330 (100 mg/kg) adenosine (0.3 mmol/kg), and pentoxifylline (100 mg/kg), inhibited both TNF-α mRNA expression and hepatocyte proliferation 48 hours after the injection. These experimental results strongly support the hypothesis that TNF-α positively regulates the hepatocyte proliferation induced in rats by the mitogen, lead nitrate.
Hepatitis B and C coinfections and persistent hepatitis B infections: Clinical outcome and liver pathology after transplantation
Authors: Huang E J , Wright T L , Lake J R , Combs C , Ferrell L D
Published: November 2004

Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are common complications after orthotopic liver transplantation (OLT), but the liver pathology and clinical outcomes of HBV infection with HCV coinfection have not been thoroughly examined. In this study, we used the polymerase chain reaction (PCR) to detect HBV and HCV in pre- and post-OLT sera of 38 patients and correlated the findings with clinical outcome and liver pathology. Of 13 patients who were HBV and HCV negative before OLT, 9 acquired HBV infection, and 4 developed acquired HBV and HCV coinfections after OLT. Persistent HBV infections were present in 10 patients. Three patients with pre-OLT HBV infections developed persistent HBV and acquired HCV coinfections after OLT; 5 with pre-OLT HCV infections developed acquired HBV and persistent HCV coinfections after OLT, and 7 had persistent HBV and HCV coinfections before and after OLT. Portal/periportal inflammation was the same in all groups; however, lobular inflammation and fibrosis were more severe in patients with persistent HBV infections and in those with acquired HBV and HCV coinfections. Two major histopathological patterns were present in patients with HBV and HCV coinfections, one with predominant features of HCV infection, and the other with those of HBV infection. Patients with post-OLT HBV and HCV coinfections had survival rates similar to those with acquired HBV infection, whereas patients with persistent HBV infections experienced more allograft loss caused by chronic hepatitis or fibrosing cytolytic hepatitis, and had a more dire clinical outcome than the others. Although the limited numbers reported in this study prevent a definitive conclusion, our data suggest that in patients with HBV and HCV coinfections, the presence of HCV may improve the clinical outcome as compared with the expected outcome of persistent HBV infection alone.
Epitope mapping and reactivity of autoantibodies to the E2 component of 2-oxoglutarate dehydrogenase complex in primary biliary cirrhosis using recombinant 2-oxoglutarate dehydrogenase complex
Authors: Moteki S , Leung P S , Dickson E R , Van Thiel D H , Galperin C , Buch T , Alarcon-Segovia D , Kershenobich D , Kawano K , Coppel R L , Matuda S , Gershwin M E
Published: November 2004

Five different target mitochondrial autoantigens recognized by sera from patients with primary biliary cirrhosis (PBC) have been identified as subunits of the following 2-oxo acid dehydrogenase complexes: the pyruvate dehydrogenase complex (PDC), the branched chain 2-oxo acid dehydrogenase complex (BCOADC), and the 2-oxoglutarate dehydrogenase complex (OGDC). Unlike the E2 subunits of PDC (PDC-E2) and BCOADC (BCOADC-E2), the E2 subunits of OGDC (OGDC-E2) reactivity of PBC sera and the reactive epitope of OGDC-D2 have not hitherto been studied in detail. In this report, we took advantage of a recombinant fusion protein for OGDC-E2 to address these issues. Eighty of 268 (29.9%) PBC patient sera but none of the 45 controls reacted with recombinant OGDC-E2. The recombinant OGDC-E2 was judged to express the immunodominant epitope, because when sera from patients with PBC were preabsorbed with the recombinant fusion protein, such sera were depleted of reactivity against 48 kD OGDC-E2 when probed on beef heart mitochondria (BHM) but retained reactivity toward PDC-E2 and/or BCOADC-E2. Furthermore, affinity-purified PBC sera against recombinant OGDC-E2 reacted only with native OGDC-E2 and not with any other enzyme components of the 2-oxo acid dehydrogenase complex. Antimitochondrial autoantibodies (AMA) against OGDC-E2 included immunoglobulin (Ig)G2, IgG3 and IgM and the relative titers were as follows: IgG2 > IgG3 > IgM. Finally, using overlapping recombinant polypeptides, it was determined that a minimum of 81 amino acids (residues 67-147) corresponding to the lipoyl domain of OGDC-E2 are necessary for reactivity, suggesting that a conformational autoepitope is recognized by AMA. These data suggest that each of the 2-oxo acid dehydrogenase enzymes has distinct antigenicity despite their similarities in structure and function. The availability of recombinant OGDC-E2 autoantigen will allow the design of additional studies to further our understanding of the role of mitochondrial autoantigens in the pathogenesis of PBC.
Clinical significance of vascular endothelial growth factor and basic fibroblast growth factor gene expression in liver tumor
Authors: Mise M , Arii S , Higashituji H , Furutani M , Niwano M , Harada T , Ishigami S , Toda Y , Nakayama H , Fukumoto M , Fujita J , Imamura M
Published: November 2004

Hepatocellular carcinoma (HCC) is a typical hypervascular tumor. However, the relationship between the vascularity of HCC and the expression of angiogenic factors has not been investigated. In addition, no detailed studies have examined the possible involvement of angiogenic factors in the grade of malignancy of HCC. The aim of this study was to determine which angiogenic factors regulate tumor angiogenesis and contribute to the invasive ability of liver tumors, especially of HCC. Northern blot analysis was used to examine the transcriptional expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), and acidic FGF in resected surgical specimens (20 HCC and 9 metastatic liver tumors). Correlations between messenger RNA (mRNA) expression and arteriographic findings, as well as histopathological findings, were evaluated. Immunohistochemistry was performed to identify the localization of cells expressing VEGF in HCC. Higher levels of VEGF mRNA were observed in 12 of 20 HCC and 2 of 9 metastatic liver tumors than in corresponding nontumorous tissues. The degree of VEGF mRNA expression was significantly correlated with the intensity of tumor staining in angiograms (P <.01). On immunohistochemical observation, VEGF protein was intensely detected in HCC cells. Furthermore, basic FGF mRNA was detected in 9 of 20 HCC and was related to the capsular infiltration of cancer cells (P <.05). In contrast, no significant difference was observed in the very low levels of acidic FGF mRNA found in the tumorous and nontumorous portions of the liver. In conclusion, these results suggest that VEGF contributes to angiogenesis of liver tumors, whereas basic FGF may be involved in the invasion of HCC into the surrounding tissues.
Effects of long-term administration of octreotide in portal vein-stenosed rats
Authors: Lin H , Yang M C , Hou M , Li S , Huang Y , Yu P , Tsai Y , Lee S
Published: November 2004

The hemodynamic effects of long-term administration of octreotide in portal hypertension has not been established. In addition, whether long-term octreotide treatment prevents the development of portosystemic shunts has not yet been evaluated. Hence, the current study was undertaken to evaluate the effects of long-term administration of octreotide in rats with portal vein stenosis. Immediately after portal vein stenosis or sham operation, rats were given either a long-term octreotide administration of 100 μg/kg or a placebo every 12 hours by subcutaneous injection for 14 consecutive days. Systemic hemodynamics and regional blood flows, degree of mesenteric-systemic shunts, and plasma glucagon concentrations were measured after the final dose of octreotide or placebo. A fifth group of portal vein-stenosed rats received hemodynamic and plasma glucagon measurements after 1-day octreotide treatment given at 14 days after surgery. Long-term octreotide treatment modified the hyperdynamic circulation without affecting the degree of mesenteric-systemic shunts, and 1-day octreotide treatment decreased portal tributary blood flow without affecting the portal pressure, systemic hemodynamics, and degree of mesenteric-systemic shunts. Plasma glucagon levels were decreased in portal vein-stenosed rats receiving either long-term or 1-day octreodtide compared with rats receiving placebo. In contrast, chronic octreotide treatment did not affect any of the hemodynamic values or plasma glucagon levels in sham-operated rats. In conclusion, long-term administration of octreotide modified in part the development of portal hypertension and hyperdynamic circulation in portal vein-stenosed rats without affecting the degree of mesenteric-systemic shunts.
α2-Macroglobulin is mainly produced by cancer cells and not by hepatocytes in rats with colon carcinoma metastases in liver
Authors: Smorenburg S M , Griffini P , Tiggelman A , Moorman A F , Boers W , Van Noorden C J
Published: November 2004

Localization and production of α2-macroglobulin (α2M), a multifunctional binding protein with protease and cytokine scavenging properties, was studied in situ in rat livers containing experimentally induced colon carcinoma metastases by means of immunocytochemistry and in situ hybridization methods. The study was performed to investigate whether α2M production by hepatocytes plays a role in the defense against the growth of metastases on the basis of its protease inhibiting capacity. It was found that colon cancer cells in all developmental stages of the metastases contained large amounts of messenger RNA (mRNA) of α2M but hardly any α2M protein. Cancer cells in culture contained large amounts of both mRNA and protein of α2M. In contrast, stromal cells and liver cells did not show positivity for α2M mRNA above background levels. The exception was a few layers of hepatocytes around the latest stage of metastases. Hepatocytes contained both α2M mRNA and protein only when Kupffer cells were present, indicating that α2M mRNA production was induced via Kupffer cells. On the other hand, α2M protein was found in high amounts in the sinusoids and stroma of all metastases, irrespective of their developmental stage. Increased levels of α2M could not be detected in serum in all but one rat tested (n=8). It is concluded that production of α2M by hepatocytes occurs only around the latest developmental stage of metastases and that α2M does not play a significant role in the defense against metastatic cancer growth in rat liver. In contrast, cancer cells produce and secrete large amounts of α2M, which seems to be linked with their tumorigenicity. We suggest that this α2M captures cytokines rather than proteases by complex formation. These complexes were observed using immunocytochemical staining for α2M protein indicating that it was captured by either stromal cells, sinusoidal cells, or hepatocytes that are in direct contact with cancer cells, Therefore, changes in serum levels of α2M were limited, indicating that these levels do not reflect local production and effects of α2M.
Changes in rat liver gene expression induced by thioacetamide: Protective role of S -adenosyl-l-methionine by a glutathione-dependent mechanism
Authors: Mesa M L , Carrizosa R , Martinez-Honduvilla C , Benito M , Fabregat I
Published: November 2004

Chronic liver damage induced by thioacetamide (TAM) was accompanied by changes in the expression of genes related to growth (β-actin) and function (albumin and haptoglobin) of the liver. Their messenger RNA (mRNA) levels increased during the first days after TAM administration, but 4 to 7 days after prolonged treatment with this drug, liver gene expression was considerable decreased. TAM-induced changes in albumin and β-actin mRNA levels were prevented by cotreatment with S-adenosyl-l-methionine (SAM). We have investigated the possible involvement of glutathione in the protective mechanism of SAM. Firstly, we found that TAM treatment in the rat induced changes in liver glutathione disulfide (GSSG) levels, with a concomitant increase in the glutathione reductase enzymatic activity, these changes being abolished when animals were cotreated with TAM and SAM. Secondly, when rats were pretreated with buthionine sulfoximine (BSO), a glutathione synthesis inhibitor, before thioacetamide administration, the beneficial effect of SAM on liver gene expression was completely abolished. These results were confirmed by assaying the alanine transaminase serum activity, a parameter of liver injury. TAM-treated animals had increases in this serum enzyme, this effect being partially blocked by SAM. However, in BSO-pretreated rats, the protective effect of SAM was impaired. Taking together all these results, we propose a glutathione-dependent mechanism in the SAM protection against TAM hepatotoxicity in the rat.
Liver-targeted antiviral nucleosides: Enhanced antiviral activity of phosphatidyl-dideoxyguanosine versus dideoxyguanosine in woodchuck hepatitis virus infection in vivo
Authors: Korba B A , Xie H , Wright K N , Hornbuckle W E , Gerin J L , Tennant B C , Hostetler K Y
Published: November 2004

It would be desirable to develop antiviral agents that can be targeted to liver to enhance their antiviral effects and reduce nonhepatic toxicity. 2′,3′-Dideoxyguanosine (ddG) has been found to be a potent and selective antihepatitis B agent both in vitro and in vivo. To evaluate ddG and its liver-targeted analog, we synthesized a series of phosphatidyl-ddGs and incubated them with 2.2.15 cells, which chronically produce hepatitis B virus. 1,2-Dipalmitoylphosphatidyl- dideoxyguanosine (DPP-ddG) inhibited the production of hepatitis B virus (HBV) DNA in the culture medium by 90% at 4.5 mumol/L versus 9.1 mumol/L for ddG, while the liposome vehicle itself had no effect. To compare the efficacy of free ddG with its lipid prodrug in vivo, we treated woodchucks that were experimentally infected with woodchuck hepatitis virus (WHV) for 4 weeks by intraperitoneal injection of 2.6 mumol/kg/d of free ddG or liposomes containing 2.6 mumol/kg/d of DPP- ddG. Liposomal DPP-ddG reduced serum WHV DNA by 23- to 46-fold at the end of the fourth week, while free ddG reduced serum WHV DNA by 2.2- to 10.4-fold. Treatment with small unilamellar liposomes containing DPP- ddG is substantially more effective than free ddG in reducing WHV-DNA levels in serum in WHV-infected woodchucks. The data suggest that the use of lipid prodrugs to target the liver may be useful in enhancing antiviral therapy of hepatitis.
Elevation of γδ T lymphocytes in peripheral blood and livers of patients with primary sclerosing cholangitis and other autoimmune liver diseases
Authors: Martins E B , Graham A K , Chapman R W , Fleming K A
Published: November 2004

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease that is possibly an autoimmune disease. Although γδ T cells represent a small proportion of the total T-cell population in healthy individuals, there is evidence to suggest a role for these cells in autoimmunity. Accordingly, the aim of this study was to investigate the population of γδ T cells in patients with PSC, compared with other chronic liver diseases. An elevation in the percentage and absolute numbers of γδ T cells was found in the peripheral blood of patients with PSC (8.66% and 0.13 x 10-6/L [P < .01 and < .05, respectively]) and autoimmune hepatitis (AIH) (8.03% and 0.13 x 10-6/L [both P < 0.001]) compared with controls (4.10% and 0.06 x 10-6/L). We also found an elevation in the percentage and absolute numbers of γδ T cells in the portal areas of patients with PSC (10.55% and 4.33 [P < .001 and < .001, respectively]), AIH (7.16% and 4.55 [P = .001 and < .001, respectively]), and primary biliary cirrhosis (PBC) (5.57% and 3.49 [P = .008 and < .001, respectively]) when compared with controls (2.23% and 0.81). These findings suggest a role for γδ T cells in the mechanism of immune damage in autoimmune liver diseases.
Absence of the canalicular isoform of the MRP gene-encoded conjugate export pump from the hepatocytes in Dubin-Johnson syndrome
Authors: Kartenbeck J , Leuschner U , Mayer R , Keppler D
Published: November 2004

The Dubin-Johnson syndrome is characterized by an inherited defect in the secretion of amphiphilic anionic conjugates from hepatocytes into the bile. We have recently identified the membrane protein mediating the adenosine triphosphate (ATP)-dependent transport of glutathione and glucuronate conjugates as a multidrug-resistance protein (MRP) and localized it to the canalicular as well as to the lateral hepatocyte plasma membrane. In the present study we show the selective absence of the canalicular isoform of MRP (cMRP) from the hepatocytes in a patient with Dubin-Johnson syndrome by double-label immunofluorescence and confocal laser scanning microscopy using antibodies directed against MRP and dipeptidyl-peptidase IV (DPPIV). Another isoform of MRP was detected, however, in the lateral hepatocyte membrane of the patient. Moreover, MRP was present on immunoblots of erythrocyte membranes from Dubin-Johnson syndrome and normal humans. These findings are analogous to our recent observations on the localization of the rat homolog of MRP and its canalicular isoform, cMRP, in normal and transport- deficient GY/TR- Wistar rat liver. The elucidation of the selective absence of an isoform of MRP and from the canalicular membrane domain in conjunction with the defined substrate specificity of the MRP and cMRP gene-encoded conjugate export pumps contributes to the molecular definition of the transport defect in Dubin-Johnson syndrome.
Evidence of increased guanylate cyclase activation by acetylcysteine in fulminant hepatic failure
Authors: Harrison P , Wendon J , Williams R
Published: November 2004

Patients with fulminant hepatic failure (FHF) have a severe microcirculatory disturbance causing tissue hypoxia. Infusion of acetylcysteine improves survival and reduces the incidence of multiorgan failure by enhancing tissue oxygenation. Because the observed circulatory effects of acetylcysteine in FHF are similar to and synergistic with those produced by the microcirculatory vasodilator prostacyclin, we postulated that acetylcysteine might potentiate an endogenous vasodilator. Nitric oxide, a vasodilator that activates soluble guanylate cyclase, is a possible candidate as plasma cyclic 3′,5′-guanosine monophosphate (cGMP) is raised in FHF, and in vitro acetylcysteine has been found to enhance soluble guanylate cyclase activity. To investigate this possible mechanism further, plasma cGMP was measured before and after acetylcysteine infusion in 24 patients with FHF and again in 6 patients after recovery from acute illness. cGMP levels were high in FHF during acute illness (median, 7.0 nmol/L [interquartile range, 2.6-10.0]) in comparison with levels taken after recovery (1.5 nmol/L [1.0-1.9]; P < .05). Levels rose further after acetylcysteine infusion in the FHF cases (mean increase, 204% [95% CI; 49 to +360]; P < .01) but not in the cases after recovery (38% [-7 to +84]). There were no significant changes in levels of plasma atrial natriuretic peptide (ANP) or cyclic adenosine monophosphate (cAMP) (mean increases, 8% [-6 to +22] and 17% [-9 to +43], respectively). The findings further support the hypothesis that the beneficial hemodynamic effects of acetylcysteine in FHF are mediated by enhancing the activity of the nitric oxide/soluble guanylate cyclase enzyme system.