bluuebunny/crossref_metadata_2025 huggingface dataset:
Bridge‐Mediated Electron Transfer and Multiple Reaction Coordinates
Authors: Newton Marshall D.
Published: November 2004

In the case of superexchange tunneling, sensitivity of the tunneling gap (Δ) to progress along the thermal et reaction coordinate (including molecular as well as solvent contributions) has been formulated in terms of a general linear response framework, which is used to express the correlation between linearly independent reaction coordinates for distinct et steps. When the tunneling gap is relatively small (i.e., of the order of magnitude of reorganization energies), the corresponding sensitivity of the donor (D)/acceptor (A) coupling (HDA) and its distance dependence (decay coefficient ß) may be significant. The magnitude of Δ at the thermal et transition state has been compared with other reference values obtainable from optical or thermodynamic data. The initial state at equilibrium yields an upper bound for Δ, and so also does the equilibrium free energy change for charge injection onto the bridge in cases of et processes which are only moderately exothermic. The in vacuo value of Δ may constitute either an upper or lower bound, depending on the nature of the et process (charge separation or charge shift) and the details of the relevant reorganization energies.
Ultrafast Energy Redistribution in Photoexcited Sodium‐Ammonia Clusters
Authors: Schulz Claus Peter , Scholz Axel , Hertel Ingolf V.
Published: November 2004

The dynamics in photoexcited Na(NH3)n clusters up to n = 20 using femtosecond laser pump and probe techniques are investigated. It is found that electronic excitation energy of the metal atom chromophore is transferred to internal vibrations of the surrounding ammonia solvent molecules. The transfer time strongly depends on the number of ammonia molecules bound to the sodium atom, decreasing from 2000 ps when only one ammonia molecules is attached to the metal atom down to a limiting value of about 100 fs for Na(NH3)10. These results can be understood in terms of an internal energy transfer where the rates are governed by the density of states and the Franck‐Condon overlap of the acceptor modes.
Time‐Resolved Fluence Studies and Delayed Ionization of the Niobium‐Carbon Cluster System
Authors: Stairs Jason R. , Peppernick Samuel J. , Davis Kevin M. , Castleman A. Welford
Published: November 2004

The effect of laser fluence on the process of delayed ionization in niobium‐carbon clusters is studied over the range of 1.25 × 104 to 9.175 × 104 W/cm2 (3.7 mJ/pulse to 0.5 mJ/pulse) with a 308‐nm XeCl Excimer laser. Delayed ionization has been observed in some cluster systems where the ionization energy of the cluster is lower than its binding energy. This characteristic allows the cluster to act as its own heat bath in which the ionization energy can be stored in the vibrational modes. Through multiphoton excitation via a nanosecond‐pulsed laser, an electron is ejected on the microsecond timescale. Fluence studies were performed in order to measure the degree of multiphoton ionization that occurs during delayed ionization. A new data analysis technique, referred to as a “time‐resolved fluence study”, is presented which demonstrates the ability of clusters differing in size to store various amounts of vibrational energy.
Dynamic effects related to steady‐state multiplicity in continuous Saccharomyces cerevisiae cultivations
Authors: Lei Frede , Olsson Lisbeth , Jørgensen Sten Bay
Published: November 2004

The behavioral differences between chemostat and productostat cultivation of aerobic glucose‐limited Saccharomyces cerevisiae were investigated. Three types of experiments were conducted: a chemostat, where the dilution rate was shifted up or down in stepwise manner; and a productostat, with either stepwise changed or a rampwise increased ethanol setpoint, i.e., an accelero‐productostat. The transient responses from chemostat and productostat experiments were interpreted using a simple metabolic flux model. In a productostat it was possible to obtain oxido‐reductive steady states at dilution rates far below Dcrit due to a strong repression of the respiratory system. However, these steady states could not be obtained in a chemostat, since a dilution rate shift‐down from an oxido‐reductive steady state led to a derepression of the respiratory system. It can therefore be concluded that the range of dilution rates where steady‐state multiplicity can be obtained differs depending on the operation mode and that this dilution rate multiplicity range may appear larger in a productostat than in a chemostat. A more narrow multiplicity range, however, was obtained when the productostat was operated as an accelero‐productostat. © 2004 Wiley Periodicals, Inc.
Langmuir–Shäfer Transfer of Fullerenes and Porphyrins: Formation, Deposition, and Application of Versatile Films
Authors: Conoci Sabrina , Guldi Dirk M. , Nardis Sara , Paolesse Roberto , Kordatos Konstantinos , Prato Maurizio , Ricciardi Giampaolo , Vicente M. Graça H. , Zilbermann Israel , Valli Ludovico
Published: November 2004

Thin films consisting of a fulleropyrrolidine derivative 1 and a novel water‐soluble porphyrin 2 were prepared by the Langmuir–Shäfer (LS, horizontal lifting) method. In particular, a solution of 1 in chloroform and dimethyl sulfoxide was spread on the water surface, while porphyrin 2 (bearing peripheral anionic groups) was dissolved into the aqueous subphase. To the best of our knowledge, such a versatile method of film fabrication for fullerene/porphyrin mixed composite films has never been used before. Evidence of the effective interactions between the two moieties at the air–water interface was obtained from the analysis of the floating layers by means of surface pressure versus area per molecule Langmuir curves, Brewster angle microscopy and UV‐visible reflection spectroscopy. The characterisation of the LS films by UV‐visible spectroscopy reveals that the two constituents behave as discrete and weakly interacting π systems. The use of polarised light suggests the existence of a preferential direction of the macrocyclic rings with an edge‐on arrangement with respect to the substrate surface. Finally, photoaction spectra were recorded from films deposited by only one horizontal lifting onto indium–tin–oxide (ITO) electrodes and the observed photocurrent increased notably with increasing transfer surface pressure.
Anion Receptors Containing ‐NH Binding Sites: Hydrogen‐Bond Formation or Neat Proton Transfer?
Authors: Amendola Valeria , Boiocchi Massimo , Fabbrizzi Luigi , Palchetti Arianna
Published: November 2004

When the amide‐containing receptor 1+ is in a solution of dimethyl sulfoxide (DMSO) in the presence of basic anions (CH3COO−, F−, H2PO4−), it undergoes deprotonation of the ‐NH fragment to give the corresponding zwitterion, which can be isolated as a crystalline solid. In the presence of less basic anions (Cl−, Br−, NO3−), 1+ establishes true hydrogen‐bond interactions of decreasing intensity. The less acidic receptor 2+ undergoes neat proton transfer with only the more basic anions CH3COO− and F−, and establishes hydrogen‐bond interactions with H2PO4−. An empirical criterion for discerning neutralisation and hydrogen bonding, based on UV/Vis and 1H NMR spectra, is proposed.
Aggregation of [Cu${{\bf }{{{\bf II}\hfill \atop \bf 4\hfill}}}$] Building Blocks into [Cu${{\bf }{{{\bf II}\hfill \atop \bf 8\hfill}}}$] Clusters or a [Cu${{\bf }{{{\bf II}\hfill \atop \bf 4\hfill}}}$]∞ Chain through Subtle Chemical Control
Authors: Aromí Guillem , Ribas Joan , Gamez Patrick , Roubeau Olivier , Kooijman Huub , Spek Anthony L. , Teat Simon , MacLean Elizabeth , Stoeckli‐Evans Helen , Reedijk Jan
Published: November 2004

Coordination complexes of the ligand H3L [1,3‐bis(3‐oxo‐3‐phenylpropionyl)‐2‐hydroxy‐5‐methylbenzene] with CuII are reported. Clusters showing various nuclearities or modes of supramolecular organization have been prepared by slightly changing the reaction conditions and have been crystallographically characterized. The reaction of H3L with one equivalent of Cu(OAc)2 in DMF yields the dinuclear complex [Cu2(HL)2(dmf)2] (1). Reaction in MeOH of H3L with an increased amount of metal, in the form of Cu(NO3)2, and excess strong base (nBu4NOH) affords the cluster [Cu8(L)2(OMe)8(NO3)2] (2). Complex 2 is a dimer of two linear [Cu4] arrays bridged by methoxide ligands, where the polynucleating ligand is fully deprotonated. The [Cu4]2 clusters are linked to each other by NO3− bridges to form one‐dimensional coordination polymers. The link between [Cu8] units and their relative spatial positioning can be modified by changing the anion of the CuII salt, as demonstrated by the synthesis of the cluster polymers [Cu8(L)2(OMe)8Cl2] (3) and [Cu8(L)(OMe)7.86Br2.14] (4), where only NO3− has been replaced by Cl− or Br−, respectively. Similarly, when ClO4− is used, compound [Cu8(L)2(OMe)8(ClO4)2(MeOH)4] (5) can be isolated. It contains independent [Cu8] units. A slight change in the stoichiometry of the reaction leading to 2 affords the related complex catena‐[Cu4(L)(OMe)3(NO3)2(H2O)0.36] (6). This polymer contains essentially the same [Cu4] moiety as 2, albeit organized in a completely different arrangement. Each [Cu4] unit in 6 is linked by OMe− ligands to two such equivalent groups to form an infinite chain. Magnetic susceptibility measurements reveal weak antiferromagnetic exchange between CuII centers in 1 (J = −0.73 cm−1) and strong antiferromagnetic coupling within [Cu4] chains in 2, 5, and 6 (most negative J values of −113.8 and −177.3 cm−1 for 2 and 6, respectively).
Signal integration of metastable information communication system and its limitation
Authors: Ishiwata Junya , Kondo Michimasa , Fujisaka Takahiko
Published: November 2004

This paper considers the concept of an MSCS (metastable information communications system) for remote transmission of measured data with gradual variations of the transmission frame cycle and proposes a signal integration method for improvement of the transmission characteristics. Based on the proposed method, a signal integration algorithm for a system remotely transmitting measured sensor data from on board a moving body is derived. An improvement of the received SNR (signal‐to‐noise ratio) is demonstrated by simulation. As a specific example, the integration effect and limitation of the number of integrations determined by the relationship between the error ellipse and the speed of movement is derived with a GPS as a measurement sensor. An example result includes a maximum of 7 integrations for an allowable error of ±16 m for the GPS sensor measurement, a frame period of 1 s, and a speed of movement of 2.5 m/s, with the bit error rate improved by 8 dB when the input SNR is 0 dB. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 88(3): 44–52, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20154
Effect of nucleotide excision repair on ENU‐induced mutation in female germ cells of Drosophila melanogaster
Authors: Álvarez L. , Comendador M.A. , Sierra L.M.
Published: November 2004

The role of nucleotide excision repair (NER) in the repair of alkylation damage in the germ cells of higher eukaryotes has been studied mainly by treating postmeiotic male germ cells. Little is known about repair in actively repairing female germ cells. In this study, we treated NER‐deficient (ner‐) mus201D1 Drosophila females with N‐ethyl‐N‐nitrosourea (ENU) and determined both the mutant frequencies in the multiple locus recessive lethal (RL) test and in the single locus vermilion gene and determined the ENU mutation spectrum in the vermilion gene. The results show that ENU is mutagenic in all cell stages and that the induced frequencies increase with cell maturation, from oogonia to mature oocytes. In addition, the induced spectrum consists mainly of A:T→T:A transversions (43.8%), A:T→G:C transitions (21.9%), and A:T→C:G transversions (15.6%). G:C→A:T (3.1%) transitions, other transversions (9.4%), frameshifts (3.1%), and deletions (3.1%) were also found. Comparison of these results with those previously obtained for repair‐proficient (ner+) female germ cells reveal: 1) Differences in the RL and vermilion mutation frequencies for ner+ and ner‐ germ cells, indicating that NER is involved in the repair of ENU‐induced damage to these cells. 2) At least 15.6% of mutations in ner‐ cells may be the consequence of N‐ethylation damage and mutations of this type were not detected in ner+ cells. 3) Although differences were found in transition frequencies between ENU‐treated ner+ and ner‐ germ cells (52.2% vs. 25%), suggesting that a functional NER is involved in processing O‐ethylated damage, the role of NER in repairing O‐ethylated adducts is uncertain. Environ. Mol. Mutagen. 41:270–279, 2003. © 2003 Wiley‐Liss, Inc.
E. coli BW535, a triple mutant for the DNA repair genes xth, nth, and nfo, chronically induces the SOS response
Authors: Janion Celina , Sikora (nee Wójcik) Anna , Nowosielska Anetta , Grzesiuk Elżbieta
Published: November 2004

A strong chronic induction of the SOS response system occurs in E. coli BW535, a strain defective in nth, nfo and xth genes, and hence severely deficient in the repair of abasic sites in DNA. This was shown here by visualization of filamentous growth of the BW535 strain and by measuring the level of β‐galactosidase expressed in BW535/pSK1002 in comparison to the AB1157/pSK1002 strain. The plasmid pSK1002 bears an umuC::lacZ fusion in which lacZ is under the control of the umuC promoter and regulated under the SOS regulon. Increases in the expression of β‐galactosidase occur in BW535 without any exogenous SOS inducer. Chronic induction of the SOS response was observed previously in E. coli strains bearing mutations in certain genes that have mutator activity and BW535 is a moderate mutator strain. However, not all mutators show this property, since chronic induction of SOS was not observed in mutT or mutY mutators. MutT and MutY proteins, when active, protect bacteria from mutations induced by 8‐oxoG lesions in DNA. This suggests that accumulation of abasic sites, but not 8‐oxoG residues in DNA, induce the SOS response. Environ. Mol. Mutagen. 41:237–242, 2003. © 2003 Wiley‐Liss, Inc.
Flow past a cylinder: shear layer instability and drag crisis
Authors: Singh S. P. , Mittal S.
Published: November 2004

Flow past a circular cylinder for Re=100 to 107 is studied numerically by solving the unsteady incompressible two‐dimensional Navier–Stokes equations via a stabilized finite element formulation. It is well known that beyond Re ∼ 200 the flow develops significant three‐dimensional features. Therefore, two‐dimensional computations are expected to fall well short of predicting the flow accurately at high Re. It is fairly well accepted that the shear layer instability is primarily a two‐dimensional phenomenon. The frequency of the shear layer vortices, from the present computations, agree quite well with the Re0.67 variation observed by other researchers from experimental measurements. The main objective of this paper is to investigate a possible relationship between the drag crisis (sudden loss of drag at Re ∼ 2 × 105) and the instability of the separated shear layer. As Re is increased the transition point of shear layer, beyond which it is unstable, moves upstream. At the critical Reynolds number the transition point is located very close to the point of flow separation. As a result, the shear layer eddies cause mixing of the flow in the boundary layer. This energizes the boundary layer and leads to its reattachment. The delay in flow separation is associated with narrowing of wake, increase in Reynolds shear stress near the shoulder of the cylinder and a significant reduction in the drag and base suction coefficients. The spatial and temporal power spectra for the kinetic energy of the Re=106 flow are computed. As in two‐dimensional isotropic turbulence, E(k) varies as k−5/3 for wavenumbers higher than energy injection scale and as k−3 for lower wavenumbers. The present computations suggest that the shear layer vortices play a major role in the transition of boundary layer from laminar to turbulent state. Copyright © 2004 John Wiley & Sons, Ltd.
Gene amplifications in osteosarcoma—CGH microarray analysis
Authors: Atiye Jassu , Wolf Maija , Kaur Sippy , Monni Outi , Böhling Tom , Kivioja Aarne , Tas Éva , Serra Massimo , Tarkkanen Maija , Knuutila Sakari
Published: November 2004

Little is known about the genomic alterations underlying osteosarcoma. We performed a genomewide high‐resolution gene copy number analysis of 22 osteosarcoma samples using comparative genomic hybridization on a cDNA microarray that contained cDNA clones of about 13,000 genes. Nineteen of the 22 cases had amplifications that on average spanned more than 1 Mb and contained more than 10 genes. Numerous regions of gain and loss were identified, and their boundaries were defined at high resolution. Novel amplicons were found at 14q11, 17q25, and 22q11–q13. Earlier‐known large amplified regions were detected at 12q11–q15, 8q24, 6p12–p13, and 17p11–p13 in 8, 6, 5, and 4 of the 22 samples, respectively. Amplification of 12q was observed more frequently (36% of the cases) than previously reported. Previously known small amplicons at 1p34–p36, 1q21, 19q13, and 21q22 were seen in at least three cases. Our results implicate TOM1L2 and CYP27B1 as having roles as novel targets for the 17p and 12q amplicons, respectively. Details (www.helsinki.fi/cmg) of the amplified genes in each amplicon provide valuable raw data for further in silico studies. © 2004 Wiley‐Liss, Inc.
Quantification of apolipoprotein A-I and B messenger RNA in heavy drinkers according to liver disease
Authors: Mathurin P , Vidaud D , Vidaud M , Bedossa P , Paradis V , Ratziu V , Chaput J , Poynard T
Published: November 2004

It has previously been shown that, in heavy drinkers, serum apolipoprotein A-I (ApoA-I) levels are closely related to the degree of liver injury: they are at a maximum in patients with steatosis, begin to decrease in patients with fibrosis, and reach a minimum in patients with severe cirrhosis. In contrast with serum ApoA-I variations, serum apolipoprotein B (ApoB) levels are stable. The assessment of messenger RNA (mRNA) levels of ApoA-I and ApoB using a quantitative competitive polymerase chain reaction (PCR) method was performed in 18 alcoholic patients: 8 with normal livers or steatosis (group I), 6 with fibrosis or nonsevere cirrhosis (group II), and 4 with severe cirrhosis (group III). For ApoA-I, group I had higher serum levels (208.4 ± 37.6 mg/dL mean ± SE) and mRNA levels (0.51 ± 0.12) than group II (serum 116 ± 19 mg/dL, P < .01, mRNA 0.40 ± 0.11, P < .09) or group III (serum 56.5 ± 28.6 mg/dL, P < .01, mRNA 0.27 ± .02, P = .008). For ApoB, the three groups had similar serum ApoB levels: 129.9 ± 37.7, 121 ± 51, 120.7 ± 57.4 mg/dL. Group I presented higher levels of ApoB mRNA than those of group III (0.68 ± 0.21 vs. 0.41 ± 0.18, P < .06). There was a significant correlation between serum and mRNA levels of ApoA-I (r = .65, P = .003) but no correlation between serum and mRNA levels of ApoB (r = .19, NS). We suggest that (1) steatosis is associated with increased ApoA-I mRNA; (2) fibrosis is associated with decreased serum ApoA-I, probably caused by a posttranscriptional mechanism; (3) severe alcohol-induced cirrhosis is associated with a nonspecific decrease in ApoA-I and ApoB mRNA; and (4) in contrast to ApoA-I mRNA, the ApoB mRNA level makes a slight contribution to the ApoB serum concentration.
Proliferation, apoptosis, and induction of hepatic transcription factors are characteristics of the early response of biliary epithelial (oval) cells to chemical carcinogens
Authors: Bisgaard H C , Nagy P , Santoni-Rugiu E , Thorgeirsson S S
Published: November 2004

In this study, we used [3H]thymidine labeling of newly synthesized DNA to examine the earliest effects of 2-acetylaminofluorene (2-AAF) on the mitotic activation of cells in the adult rat liver, and in situ hybridization analysis to study the expression of three transcription factors (HNF1 beta, HNF3 γ, and HNF4), and two of the genes (α-fetoprotein [AFP] and albumin) regulated by these factors. A low dose of 2-AAF (and its analogs, 2-AF [2-aminofluorene] and N-OH-2-AAF) elicited a mitogenic response in ductal cells and nondescript periductular cells within 24 hours after administration. The compounds also induced the expression of HNF1 beta, HNF3 γ, AFP, and albumin in ductal structures but had no detectable effect of HNF4 expression. In contrast, initiation of bile duct proliferation by ligation of the common bile duct had no effect on the expression of these genes in ductal cells. In addition to inducing a mitogenic response, 2-AAF resulted in increased numbers of apoptotic cells in the portal areas, a process that contributed to overall retention of liver morphology. Our results demonstrate that 2-AAF and some of its analogs can elicit a specific mitogenic response and induce expression of the “establishment” transcription factors, HNF1 beta and HNF3 γ, in ductal cells. Our data provide further support of a precursor-product relationship between “stem-like” cells located in ductal structures, oval cells, and hepatocytes.
Impaired bile flow and disordered hepatic calcium homeostasis are early features of halothane-induced liver injury in guinea pigs
Authors: Frost L , Mahoney J , Field J , Farrell G C
Published: November 2004

To characterize the early events in liver injury produced by halothane, experiments were performed in genetically susceptible guinea pigs 19 hours after halothane exposure. Serum bile acid concentrations were fourfold increased in halothane-exposed animals compared with controls. In isolated perfused liver experiments, livers from halothane-exposed animals did not differ in hepatic oxygen uptake or in perfusion pressure at the end of experiments, but bile flow and biliary bile salt concentrations were reduced. Hepatic calcium content was increased in halothane-exposed guinea pigs compared with controls, and further experiments were performed to explore the reason for this. As determined by infusion of 45Ca to steady-state perfusate concentrations, hepatic calcium clearance was increased in halothane-exposed guinea pigs compared with controls (0.37 ± 0.06 vs. 0.28 ± 0.02 mL/min, P < .01). Decreased biliary excretion of calcium was also noted and was entirely attributable to reduced bile flow. However, although decreased excretion contributed to hepatic accumulation of calcium, it was quantitatively less important than enhanced hepatic uptake. As indicated by passage of a bolus of horseradish peroxidase from perfusate into bile, hepatic tight junction permeability was increased five-fold after halothane exposure. It is concluded that cholestasis, as exemplified by reduced bile flow, is an early feature of the liver injury produced by halothane in guinea pigs and is associated with increased tight junction permeability. Although the decrease in bile flow contributes to an early increase in hepatic calcium content, entry of calcium from the perfusion compartment is quantitatively more important.
Fulminant hepatic failure caused by ecarazine hydrochloride (a hydralazine derivative)
Authors: Tameda Y , Hamada M , Takase K , Nakano T , Kosaka Y
Published: November 2004

The cause of fulminant hepatic failure is reported to be unknown in more than half the cases in Japan. We recently reviewed 23 cases of fulminant hepatic failure that had been treated at our hospital. The cause of disease had been regarded as unknown before this study. It was found that seven of these patients had been under ecarazine hydrochloride therapy when they developed fulminant hepatic failure. We examined the reasons why fulminant hepatic failure in these seven patients had not been previously attributed to ecarazine, and found that it could be explained by the following factors: (1) the time from the start of ecarazine therapy to the onset of hepatic failure was long; (2) in all cases, hepatic failure developed more than 10 days after the clinical recognition of hepatitis; and (3) characteristic signs of drug-induced hepatic failure such as a skin rash and positive lymphocytes stimulation test with the drug were absent in all cases. Fulminant hepatic failure in these cases could be characterized by: (1) rapid decrease in serum alanine transaminase (ALT) level after discontinuation of ecarazine, (2) prolonged jaundice despite discontinuation of ecarazine, (3) high incidence of anti-nuclear antibody (ANA) (57%), and (4) histological findings of extensive hepatocellular necrosis ranging from bridging necrosis to massive necrosis. Of the seven patients, four died of fulminant hepatic failure. These four patients had received high doses of ecarazine hydrochloride for prolonged periods. Our data suggest that there may be many cases in which the cause of fulminant hepatic failure or acute hepatitis was not previously determined that can be attributed to long- term drug therapy for chronic diseases.
Ethanol feeding of micropigs alters methionine metabolism and increases hepatocellular apoptosis and proliferation
Authors: Halsted C H , Villanueva J , Chandler C J , Stabler S P , Allen R H , Muskhelishvili L , James S J , Poirier L
Published: November 2004

Chronic alcoholism is associated with increased cancer risk that may be related to ethanol-induced alterations in methionine and deoxynucleotide metabolism. These metabolic relationships were studied in micropigs fed diets for 12 months that contained 40% ethanol or cornstarch control with adequate folate. Ethanol feeding altered methionine metabolism without changing mean terminal liver folate levels. After initial equilibration to diet, ethanol feeding significantly increased monthly serum homocysteine levels while reducing serum methionine levels over the time course of the experiment. After 12 months, hepatic methionine synthase activity and the ratio of S-adenosylmethionine (SAM) to S-adenosylhomocysteine (SAH) were significantly reduced in ethanol-fed animals, whereas the ratio of liver deoxyuridine triphosphate (dUTP) to deoxythymidine triphosphate (dTTP) was increased and correlated inversely with methionine synthase activity. These findings were associated with increased frequency of hepatocytes with apoptotic bodies and positivity for proliferating cell nuclear antigen (PCNA) in livers from ethanol-fed minipigs. These studies suggest that chronic ethanol feeding perturbs methionine metabolism by impairment of methionine synthase activity, resulting in deoxynucleoside triphosphate (dNTP) imbalance, increased apoptosis, and regenerative proliferation. These biochemical alterations may provide a promoting environment for carcinogenesis during long-term ethanol exposure.
The role of cytokine networks in the local liver injury following hepatic ischemia/reperfusion in the rat
Authors: Colletti L M , Kunkel S L , Walz A , Burdick M D , Kunkel R G , Wilke C A , Strieter R M
Published: November 2004

The liver is highly susceptible to a number of pathological insults, including ischemia/reperfusion injury. We have previously employed an animal model of hepatic ischemia/reperfusion injury, and have shown that this injury induces the production and release of hepatic-derived tumor necrosis factor α (TNF-α), which mediates, in part, local liver injury following hepatic reperfusion. In the present study, we have extended these previous observations to assess whether an interrelationship exists between TNF-α and the neutrophil chemoattractant/activating factor, epithelial neutrophil activating protein, that may account for some of the pathology of neutrophil-mediated ischemia/reperfusion-induced liver injury. We observed that hepatic ischemia/reperfusion injury leads to: (1) a coincident increase in hepatic neutrophil sequestration, elevated serum alanine aminotransferase (ALT) levels, and hepatic production of epithelial neutrophil activating protein; (2) passive immunization with neutralizing antibodies to TNF-α resulted in significant suppression of hepatic-derived epithelial neutrophil activating protein; and (3) neutralization of epithelial neutrophil activating protein by passive immunization significantly attenuated neutrophil sequestration in the liver and serum ALT levels. These findings support the notion that local expression of hepatic epithelial neutrophil activating protein produced in response to TNF-α is an important mediator of the local neutrophil-dependent hepatic injury associated with hepatic ischemia/reperfusion.
Involvement of calcium in macrophage leukotriene release during experimental cirrhosis
Authors: Alric L , Pinelli E , Carrera G , Vinel J P , Beraud M , Duffaut M , Pascal J P , Pipy B
Published: November 2004

The aim of the present study was to assess the mechanism of 5-lipoxygenase metabolites (LT) secretion by peritoneal macrophages in rats wih CC14 induced cirrhosis. After stimulation with calcium ionophore A23187 or opsonized zymosan, [3H] arachidonic acid labeled macrophages from cirrhotic rats presented a significantly greater secretion of LT than macrophages from healthy controls. In addition, the phorbol ester TPA (protein kinase C activator) increased LT production only in macrophages from cirrhotic animals and not in controls. Although Ca2+ is thought to be involved in 5 lipoxygenase activation, the role of Ca2+ in LT production was studied. The use of a Ca2+-free medium as well as the addition of TMB-8 (an inhibitor of intra-cellular Ca2+ movements and of plasma membrane Ca2+ fluxes) resulted in a fall in LT production greater for macrophages from cirrhotic animals than for controls. The measurement of cytosolic Ca2+ concentration by cytofluorimetry showed that Fluo-3 loaded macrophages from cirrhotic rats had a greater cytosolic CA2+ concentration than macrophages from control animals both in basal conditions and after A23187 stimulation. Study of 45Ca2+ uptake suggest, that extra-cellular Ca2+ is implicated in the elevated cytosolic Ca2+ observed in macrophages from cirrhotic animals as compared to healthy controls. The greater Ca2+ concentration observed in macrophages from cirrhotic rats was not related to a difference in phospholipase C activation because inositol phosphate production did not differ between macrophages from healthy and cirrhotic animals. Taken together these results suggest that as compared to healthy animals, the greater LT production during cirrhosis could be dependent upon a difference in 5-lipoxygenase activation related to a rise in cytosolic Ca2+ concentration independently of inositol phosphates generation.
Hepatitis C virus RNA in peripheral blood mononuclear cells: Comparing acute and chronic hepatitis C virus infection
Authors: Chang T , Young K , Yang Y , Lei H , Wu H
Published: November 2004

Hepatitis C virus (HCV) can infect peripheral blood mononuclear cells (PBMC) of patients with chronic HCV infection. No data are available on PBMC testing for HCV RNA in acute hepatitis C. This study investigated the presence of HCV RNA in PBMC of patients with acute posttransfusion hepatitis C, compared with those with chronic HCV infection. Nested polymerase chain reaction (PCR) was applied to detect HCV RNA in 111 and 48 paired samples of serum and PBMC of 11 patients with acute posttransfusion hepatitis C and 48 patients with chronic HCV infection, respectively. In patients with acute posttransfusion hepatitis C, HCV RNA was detected in 17 of 29 (59%) and 67 of 82 (82%) serum samples collected during the incubation period and acute phase, respectively. Meanwhile, of the 48 patients with chronic HCV infection, 41 had serum HCV RNA (85%). HCV RNA was not detected in PBMC samples from incubation period or from acute-phase hepatitis, although it was detected in 12 of the 48 PBMC samples of chronically infected patients (25%) P < .005). Of the 12 PBMC specimens positive for positive-stranded HCV RNA, 6 were also positive for negative-stranded HCV RNA. Among patients with chronic HCV infection, HCV infection of PBMC was not related to age, sex, blood transfusion, serum alanine transaminase (ALT) levels, or serum virus titers. In conclusion, HCV infection of PBMC rarely exists in patients with acute hepatitis C. As HCV infection persists, the incidence of HCV infection of PBMC becomes higher.
Specificity and sensitivity of gp210 autoantibodies detected using an enzyme-linked immunosorbent assay and a synthetic polypeptide in the diagnosis of primary biliary cirrhosis
Authors: Bandin O , Courvalin J , Poupon R , Dubel L , Homberg J , Johanet C
Published: November 2004

Between 10% and 42% of patients with primary biliary cirrhosis (PBC) have been reported to have autoantibodies directed against a restricted epitope of gp210, a glycoprotein of the nuclear pore membrane. The prevalence and specificity of these antibodies was studied in a French series of 285 patients with PBC and 497 control individuals affected with other liver or autoimmune diseases. Sera were analyzed by an enzyme-linked immunosorbent assay (ELISA) that used a synthetic polypeptide containing the predominant autoepitope of gp210, in parallel to immunoblotting of gp210 protein and immunofluorescence microscopy. Autoantibodies to the gp210 epitope detected by ELISA were 25.5% sensitive and 99.5% specific for the diagnosis of PBC. These results were in agreement with a 99.4% specificity with immunoblotting analysis and a 96.6% specificity with immunofluorescence. In a subset of PBC patients without detectable antimitochondrial autoantibodies (AMA), gp210 autoantibodies were found in 7 of 15 patients (47%). Therefore, gp210 autoantibodies are highly specific for PBC and may be of particular utility in assessing patients without AMA or with other atypical presentations.
Heat serum inactivation as a mandatory procedure for antiactin antibody detection in cell culture
Authors: Cancado E L , Vilas-Boas L S , Abrantes-Lemos C P , Novo N F , Porta G , Da Silva L C , Laudanna A A
Published: November 2004

In autoimmune hepatitis (AIH), the smooth-muscle antibody is specific for polymerized actin. Detection of antiactin antibody (AAA) has been hampered by technical problems. We have investigated AAA in 30 sera from patients with liver diseases and smooth-muscle antibody. AAA was detected by indirect immunofluorescence in 1:40, 1:80, and 1:160 dilutions. Five techniques were performed using fibroblasts: with vinblastine (A); without drugs (B); with sodium citrate (C); without drugs but with heat serum inactivation (D); and with sodium citrate and heat serum inactivation (E). For comparative analysis, we considered: the total number of AAA-positive sera regardless of the dilution in which reactivity was observed, as well as in each dilution separately; and the comparison of AAA intensity between 1:40 x 1:80, 1:40 x 1:160, and 1:80 x 1:160 dilutions. AAA was more positive in techniques B, C, D, and E than in A (P < .001) in general, and in each dilution separately. AAA was more positive in technique D than in B in 1:40 (P = .0005) and 1:80 dilutions (P = .03), as well as in E than in C (P = .0001) in 1:40 dilution. Techniques B and D yielded results similar to C and E, respectively. AAA staining was significantly more intense in 1:80 and 1:160 than in 1:40 dilution in A, B, and C; it was both significantly less intense in 1:80 and 1:160 than in 1:40 dilution and in 1:80 than in 1:160 in techniques D and E. We concluded that heat inactivation increased AAA seropositivity/intensity in 1:40 and 1:80 dilutions, preventing false-negative results; actin polymerization with sodium citrate did not enhanced AAA seropositivity/intensity. The technique with vinblastine was the least effective.
Biliary malignancies in primary sclerosing cholangitis: Timing for liver transplantation
Authors: Nashan B , Schlitt H J , Tusch G , Oldhafer K J , Ringe B , Wagner S , Pichlmayr R
Published: November 2004

Primary sclerosing cholangitis (PSC) is a chronic inflammatory disease associated in 10% to 36% of those with hepatobiliary malignancies, which are, in the majority of cases, not known prior to transplantation. Diagnosis of carcinomas in a PSC setting at an early stage has not yet been achieved, because there are no differences in the age of patients or clinical course, particularly with regard to the time between diagnosis of PSC and detection of carcinomas. To assess optimal timing for transplantation in patients with PSC, we applied the Mayo survival model to 48 patients receiving transplants for that disease in our center between 1972 and 1994. Of these patients, 10 had a biliary malignancy, which was incidental in 9. According to the Mayo model, low-, moderate-, and high-risk groups of patients could be formed. The actuarial patient survivals at 1 and 7 years were 100% and 100% (low risk), 68.6% and 68.6% (moderate risk), and 54.6% and 46.8% (high risk), respectively. Patients with a biliary malignancy had a 30% survival at 1 year; none survived 6 years. Local recurrence of the tumor was found in 3 patients, 2 of them with low tumor stages at the time of transplantation. Analysis of the Mayo Model risk scores demonstrated a marked increase in the incidence of biliary malignancies at a score above 4.4. All patients with tumors were found to have a score above 4. Moreover, the prevalence rate rose from 14.3% in the low-risk group to 33.3% in the moderate-risk group. There was no difference in the clinical courses at 6 to 12 months prior to transplantation; in particular, the bilirubin levels (PSC alone, 250 ± 230 mumol/L; PSC with carcinoma, 288 ± 182 mumol/L) did not differ significantly (P > .05) between both patient groups. Because the outcome after transplantation is poor even in patients with low-grade malignancies, early timing of transplantation in patients with PSC is suggested to prevent formation of biliary malignancies. Therefore, regular scoring of patients with the Mayo Model risk score is suggested, and transplantation should be taken into consideration at scores above 4.
Auxiliary liver transplantation: Regeneration of the native liver and outcome in 30 patients with fulminant hepatic failure-a multicenter European study
Authors: Chenard-Neu M , Boudjema K , Bernuau J , Degott C , Belghiti J , Cherqui D , Costes V , Domergue J , Durand F , Erhard J , De Hemptinne B , Gubernatis G , Hadengue A , Kemnitz J , McCarthy M , Maschek H , Mentha G , Oldhafer K , Portmann B , Praet M , Ringers J , Rogiers X , Rubbia L , Schalm S , Kate F T , Terpstra O , Van Hoek B , Williams R , Zafrani E , Cinqualbre J , Wolf P , Jaeck D , Bellocq J
Published: November 2004

Auxiliary liver transplantation (LT) is a special procedure of LT which could be proposed to patients with fulminant hepatic failure (FHF) and has for aim that complete regeneration of the native liver (NL) left in place will allow the graft recipient to resume normal liver function after allograft withdrawal.

We report 30 cases of auxiliary LT performed for FHF in 12 European centers. Twenty-five of 30 patients were younger than 50 years. The cause of FHF was hepatitis A virus (HAV) in 4 patients, hepatitis B virus (HBV) in 7, paracetamol overdose in 5, ecstasy in 2, hepatotoxic drugs in 4, autoimmune hepatitis in 2, liver lesions of preeclampsia in 1 and unknown in 5. A postoperative, both clinical and histological follow-up of more than 3 weeks was obtained in 22 patients, enabling us to look for indicators predictive of NL regeneration and outcome. Histological changes observed in the NL included complete regeneration in 68%, incomplete regeneration with obvious fibrous sequelae in 14% and severe liver fibrosis or cirrhosis in 18%, of the 22 patients studied. The percentage and distribution of necrosis observed in tissue samples of the NL at the time of transplantation was not related to the final outcome. Complete NL regeneration was observed in 15 patients, out of whom 14 were younger than 40 years. Patients with complete regeneration were mainly affected by FHF due to HAV, HBV, or paracetamol overdose. After a follow-up of 18/11 (mean/median) months (range, 3 to 67 months), 19 of the 30 patients (63%) survived and 13 of them (68%), i.e., 43% of the 30 patients, had resumed normal NL function, with interrupted immunosuppression, the ultimate goal of emergency auxiliary LT.

We conclude that, in patients with FHF, auxiliary LT is a procedure feasible in a number of centers and is associated with a complete regeneration capability of the NL in a majority of survivors, especially in those younger than 40 years. Confirmation of these encouraging preliminary results by large-scale prospective studies is required.
The effect of posture on central blood volume in patients with preascitic cirrhosis on a sodium-restricted diet
Authors: Wong F , Liu P , Allidina Y , Blendis L
Published: November 2004

The status of the central blood volume in cirrhosis is controversial. A combination of sodium restriction and upright posture, which redistributes intravascular volume to dependent parts of the body should further aggravate a contracted central blood volume reduction. The aim of this study was to determine the effect of upright posture and sodium restriction on central blood volume (CBV) in preascitic cirrhotic patients, compared with controls. Eight male, preascitic, alcoholic cirrhotic subjects and eight healthy male controls were studied while on a 20-mmol/d sodium diet. Measurements of CBV by radionuclide angiography, and neurohumoral factors were performed on day 7 in both supine and erect positions and cardiac output and systemic vascular resistance (SVR) was calculated. Sodium restriction resulted in less weight loss in the cirrhotic patients (P = .03), with significantly lower plasma renin activity (P = .001). Similar central blood volumes and systemic hemodynamics were observed in both groups in the supine posture. In contrast to the cirrhotic patients, in the control subjects, upright posture resulted in a significant reduction in cardiac output (P = .002) and increase in SVR (P = .005), associated with a decrease in all blood volumes which were significantly less than in the cirrhotic patients. Mean arterial pressure was maintained in both groups in both postures. In conclusion, with sodium restriction, preascitic cirrhotic patients have less intravascular volume contraction than control patients. Erect posture results in redistribution of this relatively expanded intravascular volume to the CBV. Therefore, a low-sodium diet can be safely administered in preascitic cirrhotic patients.
Interferon gamma decreases hepatic stellate cell activation and extracellular matrix deposition in rat liver fibrosis
Authors: Baroni G S , D’Ambrosio L , Curto P , Casini A , Mancini R , Jezequel A M , Benedetti A
Published: November 2004

Interferon gamma (IFN-γ) inhibits in vitro the activation of hepatic stellate cells (HSC), the primary extracellular matrix-producing cells in liver fibrosis. This study was undertaken to determine in vivo the effect of IFN-γ in the rat model of liver fibrosis induced by dimethylnitrosamine (DMN), where HSC activation represents an early response to cell injury. Rats were killed after 1 or 3 weeks of treatment with DMN, IFN-γ, DMN + IFN-γ, or saline. Immunohistochemistry was used to identify proliferating (desmin- positive/bromodeoxyuridine (BrdU)-positive cells) and activated (α- smooth-muscle actin [α-SMA]-positive cells) HSCs. Collagen deposition was determined colorimetrically and by morphometry. The parenchymal extension of desmin- and actin-positive cells and of fibrotic tissue was measured by point-counting technique and expressed as a percentage of area. Western blot was used to determine laminin and fibronectin accumulation. The levels of messenger RNA (mRNA) for procollagen type I, fibronectin, and laminin were evaluated by Northern blot. No differences were observed in rats treated with either saline or IFN-γ alone. IFN-γ reduced HSC activation induced by liver injury, as shown by the decreased number of proliferating HSC and the reduction of parenchymal area occupied by α-SMA-positive cells observed in DMN + IFN-γ-treated animals compared with the DMN group. This was associated with reduced collagen, laminin, and fibronectin accumulation and lower levels of mRNA for procollagen type I, fibronectin, and laminin in the DMN + IFN-γ group. Thus, this study indicates that IFN-γ reduces extracellular matrix deposition in vivo by inhibition of HSC activation.
Localization of α2-macroglobulin protein and messenger RNA in rat liver fibrosis: Evidence for the synthesis of α2-macroglobulin within Schistosoma mansoni egg granulomas
Authors: Tiggelman A M , Boers W , Moorman A F , de Boer A J P , Van der Loos C M , Rotmans J P , Chamuleau R A
Published: November 2004

α2-Macroglobulin (α2M) in the rat is a strong-reacting acute-phase protein with potent protease-inhibiting and cytokine-binding properties. Production of α2M is ascribed mainly to liver parenchymal cells. In the present study, we investigated, by means of immunohistochemistry and in situ hybridization, whether fibrosis in the rat liver induced by Schistosoma mansoni eggs leads to local production of α2M. α2M protein and messenger RNA (mRNA) in the unaffected liver tissue, as well as serum values of α2M, were comparable in control rats and egg-injected rats, at 1, 3, and 8 weeks after injection of the eggs. α2M was homogeneously distributed across the liver lobule. In contrast, at the sites of the granulomas, a strong increase in α2M was observed. α2M mRNA was expressed by granuloma cells, but not by the surrounding liver parenchymal cells. Within the granulomas, α2M protein was present in numerous spindle-shaped cells and was diffusely distributed in the extra-cellular matrix. Using double-staining techniques, a subpopulation of the α2M-positive cells in the granulomas appeared to be desmin-positive, suggesting a myofibroblast origin. In addition, parenchymal cells directly surrounding the granulomas contained α2M protein in approximately 50% of the granulomas 1 week after injection of the eggs. In situ hybridization on consecutive sections revealed that these parenchymal cells showed only background activity of α2M mRNA, suggesting uptake of α2M-protein by these parenchymal cells and previous activation of α2M by proteases within the granuloma. The significance of the present study is that α2M is produced locally at sites of inflammation and liver fibrosis, without measurable increase of serum levels of α2M. Unexpectedly, α2M present at the sites of the granulomas is not produced by the liver parenchymal cells, but rather by granuloma cells.