bluuebunny/crossref_metadata_2025 huggingface dataset:
The Escherichia coli twin‐arginine translocase: conserved residues of TatA and TatB family components involved in protein transport
Authors: Hicks Matthew G , de Leeuw Erik , Porcelli Ida , Buchanan Grant , Berks Ben C , Palmer Tracy
Published: April 2003

The Escherichia coli Tat system serves to export folded proteins harbouring an N‐terminal twin‐arginine signal peptide across the cytoplasmic membrane. In this report we have studied the functions of conserved residues within the structurally related TatA and TatB proteins. Our results demonstrate that there are two regions within each protein of high sequence conservation that are critical for efficient Tat translocase function. The first region is the interdomain hinge between the transmembrane and the amphipathic α‐helices of TatA and TatB proteins. The second region is within the amphipathic helices of TatA and TatB. In particular an invariant phenylalanine residue within TatA proteins is essential for activity, whereas a string of glutamic acid residues on the same face of the amphipathic helix of TatB is important for function.
A new ligand for an old lipocalin: induced circular dichroism spectra reveal binding of bilirubin to bovine β‐lactoglobulin
Authors: Zsila Ferenc
Published: April 2003

This study reports that bilirubin–bovine β‐lactoglobulin (BLG) complexes exhibit very characteristic induced circular dichroism (CD) spectra in the visible absorption region. Due to intramolecular chiral exciton coupling between the dipyrrinone chromophores, the long‐wavelength negative and short‐wavelength positive CD bands clearly prove that a single bilirubin molecule binds to BLG in a left‐handed helical conformation (in pH 7.4 phosphate buffer Δϵ
min is −54 M−1 cm−1 at 467 nm and Δϵ
max is +48.5 M−1 cm−1 at 412 nm). The very low aqueous solubility and strong tendency of bilirubin molecules to aggregate around pH 7.4 meant that much more intense CD bands were measured at alkaline pH values owing to the increasing solubility of the ligand. Vanishing CD activity obtained upon titration of the complex with palmitic acid known to bind in the hydrophobic cavity of BLG indicates bilirubin to be bound at the open end mouth of the β‐barrel. Reversible changes of the induced CD spectrum due to acidic pH shift of the sample solution lead to the same conclusion.
Interaction between HERC1 and M2‐type pyruvate kinase
Authors: Garcia-Gonzalo Francesc R , Cruz Cristina , Muñoz Purificación , Mazurek Sybille , Eigenbrodt Erich , Ventura Francesc , Bartrons Ramon , Rosa Jose Luis
Published: April 2003

HERC proteins are characterized by having one or more RCC1‐like domains as well as a C‐terminal HECT domain in their amino acid sequences. This has led researchers to suggest that they may act as both guanine nucleotide exchange factors and E3 ubiquitin ligases. Here we describe a physical interaction between the HECT domain of HERC1, a giant protein involved in intracellular membrane traffic, and the M2 isoform of glycolytic enzyme pyruvate kinase (M2‐PK). Partial colocalization of endogenous proteins was observed by immunofluorescence studies. This interaction neither induced M2‐PK ubiquitination nor affected its enzymatic activity. The putative significance of the association is discussed.
Structural cooperativity in the SH3 domain studied by site‐directed mutagenesis and amide hydrogen exchange
Authors: Casares S. , Sadqi M. , López-Mayorga O. , Martı́nez J.C. , Conejero-Lara F.
Published: April 2003

We have studied the effects produced by site‐directed mutagenesis upon energetic and structural cooperativity in the Src homology region 3 domain of α‐spectrin. The mutation of Asn47 to Gly or Ala in the distal loop brings about significant changes to the global stability of the domain in spite of not affecting its structure to any great extent. The binding affinity for a proline‐rich peptide is also largely diminished in both mutant domains. We have compared the apparent Gibbs energies of the amide hydrogen–deuterium exchange (HX) between the wild‐type and the Gly47 mutant. The observed changes in the Gibbs energy of HX indicate a remarkable energetic cooperativity in this small domain. Regions of the domain's core have a high cooperativity with the position of the mutation, indicating that their HX occurs mainly in states in which the distal loop is unstructured. More flexible regions, which undergo HX mainly by local motions, show a lower but still considerable cooperativity with the distal loop. We conclude that there is an important correlation between regional stability and cooperativity in this small domain.
Structural characterization of thyroglobulin type‐1 domains of equistatin
Authors: Galeša Katja , Pain Roger , Jongsma Maarten A , Turk Vito , Lenarčič Brigita
Published: April 2003

Equistatin is a protein composed of three thyroglobulin type‐1 domains. It inhibits papain‐like cysteine proteinases and the aspartic proteinase, cathepsin D. To determine the structural basis for this inhibition we cloned and expressed the separated domains (eq d‐1, eq d‐2, eq d‐3) in Pichia pastoris. Kinetic constants for the interaction of eq d‐1 with papain and that of eq d‐2 with cathepsin D are of similar order (subnanomolar) and are comparable to the constants obtained for full‐length equistatin. The target proteinase for the third domain remains unknown. Thus, we demonstrate here that thyroglobulin type‐1 motifs per se are able to support specific structural features that enable them to inhibit proteases from different classes. The overall conformation of three domains in equistatin is such that the interaction of domains 1 or 2 with their respective target enzymes is not hindered sterically by either domain. In addition, we show that the interaction of eq d‐2 with cathepsin D results in conformational changes, which is not the case for the eq d‐1/papain interaction.
Stimulation of the α1A adrenergic receptor inhibits PDGF‐induced PDGF β receptor Tyr751 phosphorylation and PI 3‐kinase activation
Authors: Lin Hong-Ying , Ballou Lisa M , Lin Richard Z
Published: April 2003

Several reports indicate that some Gαq‐coupled receptors antagonize the activation of phosphatidylinositol (PI) 3‐kinase by receptor tyrosine kinases. We used Rat‐1 fibroblasts expressing the α1A adrenergic receptor to study how this Gαq‐coupled receptor inhibits platelet‐derived growth factor (PDGF) activation of PI 3‐kinase. Phenylephrine (PE) stimulation of the α1A adrenergic receptor inhibited PDGF‐induced binding of PI 3‐kinase to the PDGF receptor (PDGFR) and phosphorylation of the PDGFR at Tyr751, which forms a docking site for PI 3‐kinase. By contrast, activation of phospholipase Cγ by PDGF and phosphorylation of the PDGFR at Tyr716 and Tyr771 were not inhibited by PE. The protein tyrosine phosphatase SHP‐2, which dephosphorylates Tyr751 on the PDGFR, was more active in cells treated with PDGF plus PE than in cells treated with either agent alone. PDGF‐induced PI 3‐kinase signaling was also inhibited by treatment of cells with Pasteurella multocida toxin to activate Gαq. These results suggest that the α1A adrenergic receptor, and perhaps other Gαq‐coupled receptors, uses tyrosine dephosphorylation to block PI 3‐kinase activation by PDGF.
Targeting of MIST to Src‐family kinases via SKAP55–SLAP‐130 adaptor complex in mast cells1
Authors: Fujii Yasuyuki , Wakahara Shunichi , Nakao Toru , Hara Toshifumi , Ohtake Hidenori , Komurasaki Toshi , Kitamura Kunihiro , Tatsuno Akiko , Fujiwara Naruyoshi , Hozumi Nobumichi , Ra Chisei , Kitamura Daisuke , Goitsuka Ryo
Published: April 2003

MIST (mast cell immunoreceptor signal transducer; also termed Clnk) is an adaptor protein structurally related to SLP‐76‐family hematopoietic cell‐specific adaptor proteins. We demonstrate here that two major MIST‐associated phosphoproteins expressed in mast cell lines are SLAP‐130 and SKAP55, adaptors known to interact with the Src‐homology (SH) 2 domain of Src‐family protein tyrosine kinases (PTKs). MIST directly associated with SLAP‐130 via its SH2 domain, and collaboration of SLAP‐130 with SKAP55 was required for the recruitment of MIST to Lyn. Furthermore, MIST was preferentially recruited to Fyn rather than Lyn, which is regulated by higher affinity binding of SLAP‐130 and SKAP55 with the Fyn‐SH2 domain than the Lyn‐SH2 domain. Our results suggest that the MIST–SLAP‐130–SKAP55 adaptor complex functions downstream of high‐affinity IgE receptor‐associated Src‐PTKs in mast cells.
Coupling of nuclear wavepacket motion and charge separation in bacterial reaction centers
Authors: Shuvalov V.A , Yakovlev A.G
Published: April 2003

The mechanism of the charge separation and stabilization of separated charges was studied using the femtosecond absorption spectroscopy. It was found that nuclear wavepacket motions on potential energy surface of the excited state of the primary electron donor P* leads to a coherent formation of the charge separated states P+BA
−, P+HA
− and P+HB
− (where BA, HB and HA are the primary and secondary electron acceptors, respectively) in native, pheophytin‐modified and mutant reaction centers (RCs) of Rhodobacter sphaeroides R‐26 and in Chloroflexus aurantiacus RCs. The processes were studied by measurements of coherent oscillations in kinetics at 890 and 935 nm (the stimulated emission bands of P*), at 800 nm (the absorption band of BA) and at 1020 nm (the absorption band of BA
−) as well as at 760 nm (the absorption band of HA) and at 750 nm (the absorption band of HB). It was found that wavepacket motion on the 130–150 cm−1 potential surface of P* is accompanied by approaches to the intercrossing region between P* and P+BA
− surfaces at 120 and 380 fs delays emitting light at 935 nm (P*) and absorbing light at 1020 nm (P+BA
−). In the presence of Tyr M210 (Rb. sphaeroides) or M195 (C. aurantiacus) the stabilization of P+BA
− is observed within a few picosseconds in contrast to YM210W. At even earlier delay (∼40 fs) the emission at 895 nm and bleaching at 748 nm are observed in C. aurantiacus RCs showing the wavepacket approach to the intercrossing between the P* and P+HB
− surfaces at that time. The 32 cm−1 rotation mode of HOH was found to modulate the electron transfer rate probably due to including of this molecule in polar chain connecting PB and BA and participating in the charge separation. The mechanism of the charge separation and stabilization of separated charges is discussed in terms of the role of nuclear motions, of polar groups connecting P and acceptors and of proton of OH group of TyrM210.
Liposome entrapment and immunogenic studies of a synthetic lipophilic multiple antigenic peptide bearing VP1 and VP3 domains of the hepatitis A virus: a robust method for vaccine design
Authors: Haro Isabel , Pérez Silvia , Garcı́a Mónica , Chan Weng C , Ercilla Guadalupe
Published: April 2003

Multiple antigen peptides (MAP) have been demonstrated to be efficient immunological reagents for the induction of immune responses to a variety of infectious agents. Several peptide domains of the hepatitis A virus (HAV) capsid proteins, mainly VP1 and VP3, are the immunodominant targets for a protective antibody response. In the present study we analyse the immunogenic properties of a tetrameric heterogeneous palmitoyl‐derivatised MAP containing two defined HAV peptide sequences, VP1(11–25) and VP3(102–121), in rabbits immunised with either Freund's adjuvant or multilamellar liposomes. The immune response was evaluated with a specific enzyme immunoassay using MAP[VP1+VP3], VP1 and VP3 as targets. The avidity of the immune response was measured by a non‐competitive enzyme‐linked immunosorbent assay and by the surface plasmon resonance technology. Antisera raised against the lipo‐MAP peptide entrapped in liposomes demonstrated high avidity of binding with affinity rate constants approximately one order of magnitude greater than those obtained with the Freund's protocol.
Photo‐accumulation of the P+QB− radical pair state in purple bacterial reaction centres that lack the QA ubiquinone
Authors: Wakeham Marion C , Goodwin Matthew G , McKibbin Craig , Jones Michael R
Published: April 2003

Photo‐excitation of membrane‐bound Rhodobacter sphaeroides reaction centres containing the mutation Ala M260 to Trp (AM260W) resulted in the accumulation of a radical pair state involving the photo‐oxidised primary electron donor (P). This state had a lifetime of hundreds of milliseconds and its formation was inhibited by stigmatellin. The absence of the QA ubiquinone in the AM260W reaction centre suggests that this long‐lived radical pair state is P+QB
−, although the exact reduction/protonation state of the QB quinone remains to be confirmed. The blockage of active branch (A‐branch) electron transfer by the AM260W mutation implies that this P+QB
− state is formed by electron transfer along the so‐called inactive branch (B‐branch) of reaction centre cofactors. We discuss how further mutations may affect the yield of the P+QB
− state, including a double alanine mutation (EL212A/DL213A) that probably has a direct effect on the efficiency of the low yield electron transfer step from the anion of the B‐branch bacteriopheophytin (HB
−) to the QB ubiquinone.
Cholesterol concentrations in violent and non-violent women suicide attempters
Authors: Vevera J. , Žukov I. , Morcinek T. , Papežová H.
Published: April 2003

The aim of this study was to evaluate whether women with a history of violent suicide attempts have lower serum cholesterol concentrations than those who attempted suicide by non-violent methods. Our retrospective study used a case-control design to compare serum total cholesterol concentration, hematocrit, red blood cell count and body mass index (BMI) in women with a history of violent (n = 19) or non-violent (n = 51) suicide attempts and of non-suicidal controls (n = 70) matched by diagnosis and age. Analysis of covariance (ANCOVA) with age as the covariate was used to analyze differences in cholesterol levels in groups according to violence. Violence was found to be a significant factor (P = 0.016). Using the Scheffé test, a significant difference (P = 0.011) was revealed between the group of violent and non-violent suicide attempters and between the violent suicide attempters and the control group. Patients with a violent suicidal attempt have significantly lower cholesterol levels than patients with non-violent attempts and the control subjects. Our findings suggest that suicide attempts should not be considered a homogenous group. They are consistent with the theory that low levels of cholesterol are associated with increased tendency for impulsive behavior and aggression and contribute to a more violent pattern of suicidal behavior.
The communicative use of pointing in autism: developmental profile and factors related to change
Authors: Camaioni L. , Perucchini P. , Muratori F. , Parrini B. , Cesari A.
Published: April 2003

Purpose. –

To describe different longitudinal profiles in communicative abilities and symptoms severity in early autism.

Methods. –

Five children with autism, aged from 3;3 to 4;10 years at baseline, were tested for production and comprehension of imperative and declarative pointing at about 4-month intervals. Concurrently with these sessions, children were evaluated in terms of cognitive and communicative abilities, and symptoms severity.

Results. –

Four subjects showed a mild to severe retardation in communicative and linguistic abilities. For production, all children exhibited the imperative pointing and only one the declarative pointing. For comprehension, two subjects showed the same profile as in production (‘only imperative’ and ‘first imperative–later declarative’, respectively). One child did not show any clear comprehension of the pointing gestures produced by the experimenter, and one child was able to understand both pointing in the same session. Childhood autism rating scale (CARS) global scores tended to decrease across sessions for all subjects and different individual profiles were identified.

Discussion. –

Declarative or experience-sharing pointing emerged later in one child only; it remained absent in four children as production, and in two children as comprehension. A preliminary conclusion based on CARS rating, is that autism involves a symptomatology that may decrease across time even if children differ in the decreasing profile relative to specific scores.
A microprobe study of element distribution in vaginal epithelial cells of the rat
Authors: Catchpole Hubert R , Engel Milton B , Jordan Steven L
Published: April 2003

Microprobe analysis of vaginal epithelial cells shed during the estrous cycle of the rat was done to determine cellular elements present in successive stages: pro‐estrus, estrus, and post‐estrus. Smears of vaginal contents were placed on carbon planchettes, fixed by freeze‐drying, and examined in a scanning microscope with an energy dispersive spectrometer. Concentrations of Na, Mg, P, S, Cl, K, and Ca were calculated (mmol/kg dry weight) and analyzed statistically. For phosphorus a significant fall at estrus correlates with a loss of nuclear and cytoplasmic nucleic acids and nucleoproteins. An increase in sulfur at estrus is consistent with an accumulation of keratins over pro‐estrus and a greater increase over the post‐estrus epithelial cells. The epithelial cells of pro‐estrus are highest in Mg and Ca. By post‐estrus, the cells have recovered their Mg, not Ca. Potassium concentrations exhibited no significant change between the successive stages.
A Pilot Study Using a Newly Devised Manual in a Programme of Education and Support for Patients Waiting for Coronary Artery bypass Surgery
Authors: Goodman Helen , Peters Emma , Matthews Rachel , Geraghty Ann , Godden Joy , Shuldham Caroline
Published: April 2003

Background: Cardiac rehabilitation programmes are widely accepted as being of benefit to patients with cardiac disease. The time spent waiting for cardiac surgery can be extremely stressful but can be used to address risk factors and provide information to reduce anxiety and prepare the patient for surgery. Aims: To pilot the usefulness of a manual for pre-operative cardiac surgical patients, and assess the feasibility and usefulness to both nurses and patients of a monthly education and support programme for patients waiting for cardiac surgery. Methods: A pilot study of 42 patients followed up for 3 months. Research tools included patient questionnaires and telephone interviews, risk factor measurements and nurse focus groups. Results: Nurses and patients evaluated the manual and overall programme favourably, although the nurses found it was very labour intensive. Changes to risk factors made during the study were small but patients valued the opportunity to raise questions which fell into the categories of medical concerns, hospital procedure and risk factors. Conclusion: The manual is a useful tool for patients waiting for cardiac surgery. The programme is useful and feasible but could be targeted more specifically to patients with raised risk factors.
Interactions between Nurses and Men Admitted with Chest Pain
Authors: White Alan K.
Published: April 2003

This paper reports on an analysis of the interactions that occurred between nurses and men admitted with acute chest pain. Background and aim: Men admitted to hospital after experiencing chest pain were the focus of a study into men's transition from being well men to ill men. During the study it became apparent that nurses adopted strategies to manage the men through this early acute phase of their illness. Methods: Data were collected through fieldwork using participant observation on an acute medical admissions ward and an intensive care unit with dedicated coronary care beds. Twenty-five men were included in the study with 10 followed through to discharge. An interpretive grounded theory was used to direct the data collection and analysis. Results: The men and nurses were seen to be part of a complex interplay, but three main types of interaction were identified: supportive, controlling and educative/informative. Discussions with the men suggests a key factor in the men's experiences was the interactions they had with the nursing and medical staff. Conclusions: Attention should be given to nurses' awareness of men's coping strategies when faced with sudden health change and how their actions impact on their recovery.
Integrating Psychological Research on Girls with Feminist Activism: A Model for Building a Liberation Psychology in the United States
Authors: Grant Kathryn E. , Finkelstein Jo-Ann S. , Lyons Aoife L.
Published: April 2003

A liberation psychology is needed to bridge the gap between psychology's focus on individual distress and broad social forces that foster such distress. We offer a model for bridging this gap by focusing on a specific area of psychology (psychological research on girls) and a specific social movement (feminist activism). Psychological research on girls and feminist activism share the common goal of improving the lives of girls and women. However, both have fallen short of this goal. This is due, in part, to the weaknesses associated with each endeavor and to the fact that the complementary strengths of each have remained isolated from the other. In this paper, we propose a common language and shared framework to integrate psychological research with feminist activism. First, we review the basic strengths and weaknesses associated with psychological research and feminist activism, with a particular focus on how they are distinct from one another. Second, we provide a taxonomic framework for integrating these two areas on the basis of the stress paradigm, with specific examples provided from our recent reviews of the literature and our own empirical work with adolescent girls. Finally, we conclude with recommendations for future work needed to integrate psychological research on girls with feminist activism toward the goal of building a liberation psychology in the United States.
Nitric Oxide–Mediated Cytoprotection of Hepatocytes From Glucose Deprivation–Induced Cytotoxicity: Involvement of Heme Oxygenase–1
Authors: Choi Byung-Min , Pae Hyun-ock , Kim Young-Myeong , Chung Hun-Taeg
Published: April 2003

Heme oxygenase–1 (HO–1) is the rate–limiting enzyme in heme catabolism, which leads to the generation of carbon monoxide (CO), biliverdin, and free iron. One of 3 mammalian HO isoforms, HO–1, is a stress–responsive protein and known to modulate such cellular functions as cytokine production, cell proliferation, and apoptosis to protect organs and tissues from acute injury. Although nitric oxide (NO)–mediated cytoprotective effects against cytotoxicity induced by glucose deprivation have been well recognized, the underlying mechanisms remain to be elucidated. Thus, we investigate the involvement of HO–1 in the cytoprotective effects of NO. Deprivation of glucose markedly reduced the viability of BNL CL.2 cells and primary rat hepatocytes. Pretreatment with NO donor, sodium nitroprusside (SNP), protected hepatocytes from glucose deprivation–induced cytotoxicity; zinc protoporphyrin (ZnPP) IX, an inhibitor of HO, was found to block the SNP–induced cytoprotection. SNP increased the induction of HO–1 protein as well as its activity in hepatocytes. A cytoprotective effect comparable to SNP was observed when the cells were transfected with HO–1 gene or preincubated with another HO–1 inducer, hemin. Additional experiments revealed the involvement of CO in the cytoprotective effect of SNP/HO–1 in BNL CL.2 cells. CO mediated cytoprotective effect through suppression of ERK MAPK activation. In conclusion, our results show that SNP protects hepatocytes from glucose deprivation–induced cytotoxicity through up–regulation of HO–1. Thus, HO–1 might be an important cellular target of NO donor with clinical implications for the prevention of acute liver injury in several pathological conditions.
Dietary Habits and Their Relations to Insulin Resistance and Postprandial Lipemia in Nonalcoholic Steatohepatitis
Authors: Musso Giovanni , Gambino Roberto , De Michieli Franco , Cassader Maurizio , Rizzetto Mario , Durazzo Marilena , Fagà Emanuela , Silli Barbara , Pagano Gianfranco
Published: April 2003

The relations of dietary habits to insulin sensitivity and postprandial triglyceride metabolism were evaluated in 25 patients with nonalcoholic steatohepatitis (NASH) and 25 age–, body mass index (BMI)–, and gender–matched healthy controls. After a 7–day alimentary record, they underwent a standard oral glucose tolerance test (OGTT), and the insulin sensitivity index (ISI) was calculated from the OGTT; an oral fat load test was also performed in 15 patients and 15 controls. The dietary intake of NASH patients was richer in saturated fat (13.7% ± 3.1% vs. 10.0% ± 2.1% total kcal, respectively, P = .0001) and in cholesterol (506 ± 108 vs. 405 ± 111 mg/d, respectively, P = .002) and was poorer in polyunsaturated fat (10.0% ± 3.5% vs. 14.5% ± 4.0% total fat, respectively, P = .0001), fiber (12.9 ± 4.1 vs. 23.2 ± 7.8 g/d, respectively, P = .000), and antioxidant vitamins C (84.3 ± 43.1 vs. 144.2 ± 63.1 mg/d, respectively, P = .0001) and E (5.4 ± 1.9 vs. 8.7 ± 2.9 mg/d, respectively, P = .0001). The ISI was significantly lower in NASH patients than in controls. Postprandial total and very low density lipoproteins triglyceride at +4 hours and +6 hours, triglyceride area under the curve, and incremental triglyceride area under the curve were higher in NASH compared with controls. Saturated fat intake correlated with ISI, with the different features of the metabolic syndrome, and with the postprandial rise of triglyceride. Postprandial apolipoprotein (Apo) B48 and ApoB100 responses in NASH were flat and strikingly dissociated from the triglyceride response, suggesting a defect in ApoB secretion. In conclusion, dietary habits may promote steatohepatitis directly by modulating hepatic triglyceride accumulation and antioxidant activity as well as indirectly by affecting insulin sensitivity and postprandial triglyceride metabolism. Our findings provide further rationale for more specific alimentary interventions, particularly in nonobese, nondiabetic normolipidemic NASH patients.
Hemodynamic Response to Pharmacological Treatment of Portal Hypertension and Long–Term Prognosis of Cirrhosis
Authors: Abraldes Juan G. , Tarantino Ilaria , Turnes Juan , Garcia-Pagan Juan Carlos , Rodés Juan , Bosch Jaime
Published: April 2003

In cirrhotic patients under pharmacologic treatment for portal hypertension, a reduction in hepatic venous pressure gradient (HVPG) of ≥20% of baseline or to ≤12 mm Hg markedly reduces the risk of variceal rebleeding. This study was aimed at evaluating whether these hemodynamic targets also prevent other complications of portal hypertension and improve long–term survival. One hundred five cirrhotic patients included in prospective trials for the prevention of variceal rebleeding were studied. Seventy–three of the patients had 2 separate HVPG measurements, at baseline and under pharmacologic therapy with propranolol ± isosorbide mononitrate. Patients were followed for up to 8 years. Survival and risk of developing portal hypertension–related complications were compared between responders and nonresponders. Twenty–eight patients showed a reduction of HVPG ≥20% of baseline or to ≤12 mm Hg (responders), and 45 patients were nonresponders. Nonresponders had a significantly greater risk of developing variceal rebleeding (P = .013), ascites (P = .025), spontaneous bacterial peritonitis (P = .003), hepatorenal syndrome (P = .026), and hepatic encephalopathy (P = .024) than responders. Eight–year cumulative probability of survival was significantly lower in nonresponders than in responders (52% vs. 95%, respectively, P = .003). At multivariate analysis, being a nonresponder was independently associated with the risk of developing rebleeding, ascites, spontaneous bacterial peritonitis, and lower survival. In conclusion, in cirrhotic patients receiving pharmacologic treatment for prevention of variceal rebleeding, a decrease in HVPG ≥20% or to ≤12 mm Hg is associated with a marked reduction in the long–term risk of developing complications of portal hypertension and with improved survival. (Hepatology 2003;37:902–908.)
C–Jun–N–Terminal Kinase Drives Cyclin D1 Expression and Proliferation During Liver Regeneration
Authors: Schwabe Robert F. , Bradham Cynthia A. , Uehara Tetsuya , Hatano Etsuro , Bennett Brydon L. , Schoonhoven Robert , Brenner David A.
Published: April 2003

The c–Jun–N–terminal kinase (JNK) pathway is strongly activated after partial hepatectomy (PH), but its role in hepatocyte proliferation is not known. In this study, JNK activity was blocked with the small molecule inhibitor JNK SP600125 in vivo and in vitro as shown by a reduction of c–Jun phosphorylation, AP–1 DNA binding activity, and c–jun messenger RNA (mRNA) expression. SP600125 inhibited proliferating cell nuclear antigen (PCNA) expression, cyclin D1 mRNA and protein expression and reduced mitotic figures after PH. Survival was reduced significantly 3 days after PH in SP600125–treated versus vehicle–treated rats (3 of 11 vs. 8 of 9, P < .01). In epidermal growth factor (EGF)–treated primary cultures of rat hepatocytes, SP600125 decreased 3H–thymidine uptake, cyclin D1 mRNA and protein expression, and inhibited the EGF–induced transcription of a cyclin D1 promoter–driven reporter gene. The defective regeneration and the decreased survival in SP600125–treated rats did not result from a major increase in apoptosis as shown by normal levels of caspase 3 activity and only slight increases in apoptotic figures. In conclusion, our data show that JNK drives G0 to G1 transition in hepatocytes and that cyclin D1 is a downstream target of the JNK pathway during liver regeneration. (Hepatology 2003;37:824–832.)
Reduced Hepatic Tumor Incidence in Cyclin G1–Deficient Mice
Authors: Jensen Michael Rugaard , Factor Valentina M. , Fantozzi Anna , Helin Kristian , Huh Chang-Goo , Thorgeirsson Snorri S.
Published: April 2003

Cyclin G1 is a transcriptional target of the tumor suppressor p53, and its expression is increased after DNA damage. Recent data show that cyclin G1 can regulate the levels of p53 by a mechanism that involves dephosphorylation of Mdm2 by protein phosphatase 2A. To understand the biologic role of cyclin G1, we have generated cyclin G1–deficient mice. In agreement with previous results, we showed that these mice develop normally, and that proliferation and induction of cellular senescence in cyclin G1–deficient mouse embryo fibroblasts are indistinguishable from wild–type fibroblasts. However, we found that the p53 levels in the cyclin G1–deficient mice are 2–fold higher that in wild–type mice. Moreover, we showed that treatment of mice with the alkylating agent 1,4–bis[N,N′–di(ethylene)–phosphamide]piperazine (Dipin), followed by partial hepatectomy, decreased G1–S transition in cyclin G1–null hepatocytes as compared with wild type. Finally, we found a significant decrease in tumor incidence, mass, and malignancy in both male and female cyclin G1–null mice after treatment with the potent hepatocarcinogen N–diethylnitrosamine. Taken with recent published data, our results suggest that cyclin G1, together with Mdm2, constitute a part of a negative feedback system that attenuates the activity of p53. In conclusion, our data suggest that the decreased tumor susceptibility after loss of cyclin G1 function is caused by the increased tumor suppressor action of p53. (Hepatology 2003;37:862–870.)
Long–Term Suppression of Hepatitis B E Antigen–Negative Chronic Hepatitis B by 24–Month Interferon Therapy
Authors: Lampertico Pietro , Del Ninno Ersilio , Viganò Mauro , Romeo Raffaella , Donato Maria Francesca , Sablon Erwin , Morabito Alberto , Colombo Massimo
Published: April 2003

To assess whether extended treatment with interferon improves the outcome of hepatitis B e antigen (HBeAg)–negative chronic hepatitis B, 101 consecutive patients were treated with 6 MU of interferon alfa 2b 3 times weekly for 24 months. During the 68–month study, 30 patients (30%) had a sustained response (i.e., normal serum transaminase levels and undetectable hepatitis B virus DNA by non–polymerase chain reaction [PCR] assays), and 15 cleared serum surface antigen. Twenty–five nonresponders, 16 relapsers, and 30 who discontinued treatment were considered treatment failures. Multivariate analysis predicted a sustained response for young age (odds ratio, 0.94; 95% confidence interval, 0.89–0.99; P = .041) and high pretreatment serum levels of immunoglobulin M (IgM) anti–hepatitis B core antigen (HBc) (odds ratio, 4.52; 95% confidence interval, 1.63–12.5; P = .004). Liver disease progressed in none of the sustained responders but in 16 with treatment failure (0% vs. 22%, P = .002); hepatocellular carcinoma (HCC) developed with similar frequency in both groups (7%). Overall, estimated 8–year complication–free survival was longer for the 30 sustained responders than the 71 patients with treatment failure (90% vs. 60%, P < .001), but 8–year patient survival was similar in the 2 groups (100% and 90%). Short complication–free survival was predicted by failure to respond to interferon (hazard ratio, 7.8; 95% confidence interval, 1.8–34.0; P = .006) and high scores for liver fibrosis (hazard ratio, 1.71; 95% confidence interval, 1.17–2.50; P = .005). In conclusion, 24 months of treatment with interferon alfa 2b led to sustained disease suppression in a significant proportion of patients with HBeAg–negative chronic hepatitis B. (Hepatology 2003;37:756–763.)
Micronutrient cofactor research with extensions to applications
Authors: McCormick Donald B
Published: April 2003

Following identification of essential micronutrients, there has been a continuum of research aimed at revealing their absorption, transport, utilization as cofactors, and excretion and secretion. Among those cases that have received our attention are vitamin B6, riboflavin, biotin, lipoate, ascorbate, and certain metal ions. Circulatory transport and cellular uptake of the water-soluble vitamins exhibit relative specificity and facilitated mechanisms at physiological concentrations. Isolation of enzymes and metabolites from micro–organisms and mammals has provided information on pathways involved in cofactor formation and metabolism. Kinases catalysing phosphorylation of B6and riboflavin have a preference for Zn2+in stereospecific chelates with adenosine triphosphate. The synthetase for flavin adenine dinucleotide prefers Mg2+. The flavin mononucleotide-dependent oxidase that converts the 5′–phosphates of pyridoxine and of pyridoxamine to pyridoxal phosphate is a connection between B6and riboflavin and is a primary control point for conversion of B6to its coenzyme. Sequencing and cloning of a side–chain oxidase for riboflavin was achieved. Details on binding and function have been delineated for some cofactor systems, especially in several flavoproteins. There is both photochemical oxidation and oxidative catabolism of B6and riboflavin. Both biotin and lipoate undergo oxidation of their acid side chains with redox cleavage of the rings. Applications from our findings include the development of affinity absorbents, enhanced drug delivery, delineation of residues in biopolymer modification, pathogen photoinactivation in blood components, and input into human dietary recommendations. Ongoing and future research in the cofactor arena can be expected to add to this panoply. At the molecular level, the way in which the same cofactor can participate in diverse catalytic reactions resides in interactions with surrounding enzyme structures that must be determined case by case. At the level of human intake, more knowledge is desirable for making micronutrient recommendations based on biochemical indicators, especially for the span between infancy and adulthood.
Crystal Structure of the Human Natural Killer Cell Activating Receptor KIR2DS2 (CD158j)
Authors: Saulquin Xavier , Gastinel Louis N. , Vivier Eric
Published: April 2003

Killer cell Ig-like receptors (KIRs) regulate the function of human natural killer and T cell subsets. A feature of the KIR locus is the clustering of homologous genes encoding for inhibitory and activating KIR. Inhibitory and activating KIR differ for ligand specificities and/or affinities. In particular, we show here with KIR tetramers that activating KIR2DS2 does not bind HLA-Cw3 molecules recognized by inhibitory KIR2DL2, despite 99% extracellular amino acid identity. We also report the 2.3-Å structure of KIR2DS2, which reveals subtle displacements of two residues (Tyr45 and Gln71) involved in the interaction of KIR2DL2 with HLA-Cw3. These results show that KIR molecules cannot tolerate any variability in their three-dimensional structure without altering their MHC class I recognition capacities. Therefore, the mode of recognition used by KIR largely differs from the conformational changes that characterize T cell receptor or NKG2D interaction with their respective ligands.
Emergent phenomena in cellular automata modeling
Authors: Hassan Yasser , Tazaki Eiichiro
Published: April 2003

It has recently been shown that an approach termed emergence system has gained popularity in a variety of fields, however, emergent computation in decentralized spatially extended systems, such as in cellular automata, is still not well understood. To accept that a system is displaying emergent behavior, the system should be constructed by describing local elementary interactions between components. This is achieved in a different way by describing global behavior and properties of the running system over a period of time. This paper introduces the emergent computational paradigm, and discusses its theoretical formulation using a new general model of cellular automata. We have also developed a technique to study the structure of the state transition of cellular automata in the limit of large system size.
Interval possibility measures: basic concepts and conditioning
Authors: Oussalah Mourad
Published: April 2003

This paper deals with the theoretical analysis of the notion of interval valued fuzzy sets (IVFS) applied to possibility measures. This permits to provide interval valued possibility measure (IVPM) and interval valued necessity measure (IVNM) as well as interval valued possibility distribution (IVPD). Particularly, two kinds of IVPM will be provided. The first one assumes a conjunctive normal form and a disjunctive normal form pertaining to a logical assertion. While the second one considers a logical AND and a logical OR as an essence to construct the underlying interval. The properties of both representations are investigated. Also, some basic mode operations involving conjunction and disjunction combinations are examined. Conditioning in the setting of IVPM is introduced considering either a canonical extension of well established rules, or more interestingly by solving the underlying Cox's axiomatic equation. Finally, some further extensions using general class of t‐norms operators are discussed.
α‐dense curves and global optimization
Authors: Cherruault Yves
Published: April 2003

α‐dense curves allow to “densify” the space Rn with a precision α. These curves can be expressed by means of a single variable. When applied to an optimization problem depending on n variables they lead to a new optimization problem according to a single variable. In this paper, we propose classes of α‐dense curves allowing to decrease the necessary calculation time for obtaining a global optimum. An estimation of this calculation time is given for the Alienor method.
Comparison of Methods for Detection of
Chlamydia trachomatis
and
Neisseria gonorrhoeae
Using Commercially Available Nucleic Acid Amplification Tests and a Liquid Pap Smear Medium
Authors: Koumans Emilia H. , Black Carolyn M. , Markowitz Lauri E. , Unger ElizabethR. , Pierce Antonya , Sawyer Mary K. , Papp John R.
Published: April 2003

Annual screening for
Chlamydia trachomatis
infection is currently recommended for sexually active women 15 to 25 years old and for women older than 25 if they have a new or multiple sex partners and have not used condoms during the previous 3 months. Annual screening for cervical abnormalities using the Pap smear has achieved a substantial reduction in morbidity and mortality from cervical cancer. Screening for
Neisseria gonorrhoeae
infection has likely contributed significantly to the reduction in the rates of gonococcal infection. The introduction of liquid Pap smear methods using exfoliated cervical cells presents an opportunity to screen for these three conditions using one specimen. We evaluated the preservation of
C. trachomatis
and
Neisseria gonorrhoeae
DNAs from ThinPrep liquid media (PreservCyt; Cytyc Corp., Boxborough, Mass.); tested the feasibility of using a clinical specimen of this medium for the detection of cytologic abnormalities,
C. trachomatis
, and
N. gonorrhoeae
; evaluated the agreement between ligase chain reaction (LCR) performed on PreservCyt and LCR performed on a cervical specimen; and compared the performance of LCR performed on PreservCyt to those of LCR performed on a cervical specimen, culture, PCR performed on a cervical specimen, on urine, and on a vaginal specimen (a multiple-site infection status standard), and transcription-mediated amplification (for
C. trachomatis
only) from 255 sexually active adolescent women. The agreement between LCR performed on PreservCyt and LCR from a cervical swab in LCx transport medium was high (for
C. trachomatis
, agreement = 0.97 and kappa = 0.92; for
N. gonorrhoeae
, agreement = 0.99 and kappa = 0.96). Test performances were similar for LCR-urine, LCR-cervix, and LCR-ThinPrep, with sensitivities from 93 to 99% for
C. trachomatis
and 81 to 83% for
N. gonorrhoeae
and specificities from 95.5 to 99% for
C. trachomatis
and 99.1 to 99.6% for
N. gonorrhoeae
using a PCR-based multiple-site infection status standard. This is the first study to examine the agreement between liquid cytologic media and multiple nucleic acid amplification tests for the detection of
C. trachomatis
and
N. gonorrhoeae
from patient samples. Cytologic fluid shows promise for simultaneous screening for cytologic abnormalities and sexually transmitted infections.
Listeria monocytogenes
Isolates from Invasive Infections: Variation of Sero- and Genotypes during an 11-Year Period in Finland
Authors: Lukinmaa Susanna , Miettinen Maria , Nakari Ulla-Maija , Korkeala Hannu , Siitonen Anja
Published: April 2003

Listeria monocytogenes
strains that were isolated from 314 human listeriosis cases in Finland during an 11-year period were analyzed by O:H serotyping and pulsed-field gel electrophoresis (PFGE). Serotyping divided the isolates into five serotypes, the most common being 1/2a (53%) and 4b (27%). During the study period, the number of cases caused by serotype 1/2a increased from 22% in 1990 to 67% in 2001, and those caused by serotype 4b decreased from 61 to 27%, respectively. PFGE with restriction enzyme
Asc
I divided the strains into 81 PFGE genotypes; among strains of serotypes 1/2a and 4b, 49 and 18 PFGE types were seen, respectively. PFGE type 1 (serotype 1/2a) was the most prevalent single type (37 strains). Together with six other, closely related PFGE types, PFGE type 1 formed a group of 71 strains, representing 23% of all 314 strains. Strains of PFGE type 1 have also been isolated from cold smoked fish, suggesting a source of human infections caused by this type. Moreover, PFGE type 24 (serotype 1/2c) was significantly associated with gender: 5% of 180 male subjects but none of 132 female subjects (
P
= 0.012). An electronic database library was created from the PFGE profiles to make possible the prompt detection of new emerging profiles and the tracing of potential infection clusters in the future.
Isolation from Blood Culture of a
Leclercia adecarboxylata
Strain Producing an SHV-12 Extended-Spectrum Beta-Lactamase
Authors: Mazzariol Annarita , Zuliani Jessica , Fontana Roberta , Cornaglia Giuseppe
Published: April 2003

We report on the first isolation of an extended-spectrum beta-lactamase-producing
Leclercia adecarboxylata
strain from the bloodstream in a 58-year-old man with acute myeloid leukemia. The strain, resistant to ceftazidime, cefotaxime, and aztreonam, produces the SHV-12 β-lactamase, one of the most common variants found in Italian nosocomial isolates of
Enterobacteriaceae
.
Use of Single-Enzyme Amplified Fragment Length Polymorphism for Typing
Pasteurella multocida
subsp.
multocida
Isolates from Pigs
Authors: Moreno A. M. , Baccaro M. R. , Ferreira A. J. P. , Pestana de Castro A. F.
Published: April 2003

Single-enzyme amplified fragment length polymorphism (SE-AFLP) analyses were used to differentiate 97 isolates of porcine
Pasteurella multocida
subsp.
multocida
. The strains, isolated from animals with pneumonia, rhinitis, and septicemia, were classified as capsular types A, D, and F. SE-AFLP showed a discriminatory index of 0.87 and identified 18 different profiles.
Occurrence of False Positives during Testing for Antibodies to Hepatitis C Virus among Volunteer Blood Donors in India
Authors: Raghuraman Sukanya , Subramaniam Thenmozhi , Daniel Dolly , Sridharan Gopalan , Abraham Priya
Published: April 2003

The hepatitis C virus antibody statuses of only 11 (21.5%) of 51 initially reactive samples from volunteer blood donors could be confirmed by using additional screening and confirmatory assays; 23 (45%) were negative by all subsequent assays. Seventeen samples (33.3%) gave variable results in the different assays. The core and NS5 antigens were most immunogenic. An algorithm for serological screening of volunteer blood donors in blood banks of developing countries is suggested.
Effects of Multiple Binding Sites on Studies of Hydrogen Bonding between Nitroxide Radicals and Solvent Molecules
Authors: Al-Bala'a Imad , Bates Richard D.
Published: April 2003

The role of more than one binding site on a nitroxide free radical in magnetic resonance determinations of the properties of the complex formed with a hydrogen donor is examined. The expression that relates observed hyperfine couplings in EPR spectra to complex formation constants and concentrations of each species in solution becomes much more complex when multiple binding sites are present, but reduces to a simpler form when binding at the two sites occurs independently and the binding at the non-nitroxide site does not produce significant differences in the hyperfine coupling constant in the complexed radical. Effects on studies of hydrogen bonding between multiple binding site nitroxides and hydrogen donor solvent molecules by other magnetic resonance methods are potentially more extreme.
Configuration and Conformation of N,N'-Diarylamidines: A Dipole Moment Study
Authors: Všetečka Václav , Oszczapowicz Janusz , Exner Otto
Published: April 2003

Dipole moments of N,N'-diphenylformamidine and its para-halogen derivatives were measured in benzene solution. Since the prototropic rearrangement is degenerate, the dipole moments can be simply interpreted in terms of the E configuration on C=N and a conformational equilibrium on C-N. The two forms, Eap and Esp are populated approximately in the 1 : 1 ratio: the former is the conformation found in the crystal. The dipole moments anticipated for individual conformations were calculated by vectoraddition of bond moments: the previously determined correction for conjugation was found unnecessary.
Relations between Structure and Antituberculotic Activity of 4-Alkoxybenzoic Acids
Authors: Waisser Karel , Kuneš Jiří , Klimeš Jiří , Polášek Miroslav , Odlerová Želmíra
Published: April 2003

Antimycobacterial activity of a series of alkoxybenzoic acids including 4-methoxybenzoic acid (II), 4-ethoxybenzoic acid (III), 4-propoxybenzoic acid (IV), 4-butoxybenzoic acid (V), 4-pentoxybenzoic acid (VI), 4-allyloxybenzoic acid (IX), 4-isopropoxybenzoic acid (VII), 4-isobutoxybenzoic acid (VIII) and 4-benzyloxybenzoic acid (X) has been determined and found to increase with the lipophilicity of the compounds expressed by the corresponding HPLC capacity factors. Also determined were the pKa values of the compounds mentioned. The most active compound, 4-pentoxybenzoic acid (VI), is comparable with commercial antituberculotics when tested in vitro.