bluuebunny/crossref_metadata_2025 huggingface dataset:
Borrelia burgdorferi-Induced Tolerance as a Model of Persistence via Immunosuppression
Authors: Diterich Isabel , Rauter Carolin , Kirschning Carsten J. , Hartung Thomas
Published: June 2003

If left untreated, infection withBorrelia burgdorferisensu lato may lead to chronic Lyme borreliosis. It is still unknown how this pathogen manages to persist in the host in the presence of competent immune cells. It was recently reported thatBorreliasuppresses the host's immune response, thus perhaps preventing the elimination of the pathogen (I. Diterich, L. Härter, D. Hassler, A. Wendel, and T. Hartung, Infect. Immun. 69:687-694, 2001). Here, we further characterizeBorrelia-induced immunomodulation in order to develop a model of this anergy. We observed that the differentBorreliapreparations that we tested, i.e., live, heat-inactivated, and sonicatedBorrelia, could desensitize human blood monocytes, as shown by attenuated cytokine release upon restimulation with any of the different preparations. Next, we investigated whether theseBorrelia-specific stimuli render monocytes tolerant, i.e. hyporesponsive, towards another Toll-like receptor 2 (TLR2) agonist, such as lipoteichoic acid from gram-positive bacteria, or towards the TLR4 agonist lipopolysaccharide. Cross-tolerance towards all tested stimuli was induced. Furthermore, using primary bone marrow cells from TLR2-deficient mice and from mice with a nonfunctional TLR4 (strain C3H/HeJ), we demonstrated that the TLR2 was required for tolerance induction byBorrelia, and using neutralizing antibodies, we identified interleukin-10 as the key mediator involved. Although peripheral blood mononuclear cells tolerized byBorreliaexhibited reduced TLR2 and TLR4 mRNA levels, the expression of the respective proteins on monocytes was not decreased, ruling out the possibility that tolerance toBorreliais attributed to a reduced TLR2 expression. In summary, we characterized tolerance induced byB. burgdorferi, describing a model of desensitization which might mirror the immunosuppression recently attributed to the persistence ofBorreliain immunocompetent hosts.
ASalmonella entericaSerovar Typhimurium Translocated Leucine-Rich Repeat Effector Protein Inhibits NF-κB-Dependent Gene Expression
Authors: Haraga Andrea , Miller Samuel I.
Published: June 2003

Nontyphoidal salmonellae are enteric pathogens that cause acute gastroenteritis and colonize the intestinal tract for prolonged periods. In the intestinal epithelia, these bacteria induce secretion of proinflammatory cytokines, such as interleukin-8 (IL-8), which leads to a profound inflammatory response through recruitment of polymorphonuclear leukocytes. Production of IL-8 induced bySalmonellaspp. is due to the activation of the transcription factors nuclear factor κB (NF-κB) and activator protein-1 (AP-1). This work demonstrates thatSalmonella entericaserovar Typhimurium can downmodulate IL-8 production after invasion of intestinal epithelial cells. TheSalmonellatranslocated effector proteins SspH1 and SptP participate in this process. SspH1 is a member of the bacterial LPX repeat protein family that localizes to the mammalian nucleus and inhibits NF-κB-dependent gene expression. AShigella flexneritranslocated effector, IpaH9.8, which has a similar structure and subcellular localization in mammalian cells, also inhibits NF-κB-dependent gene expression. We propose that suppression of inflammatory responses by intracellularS. entericaserovar Typhimurium, and perhapsShigella flexneri, contributes to bacterial colonization of host tissues and pathogenesis.
Helicobacter pyloriPreferentially Induces Interleukin 12 (IL-12) Rather than IL-6 or IL-10 in Human Dendritic Cells
Authors: Guiney Donald G. , Hasegawa Patty , Cole Sheri P.
Published: June 2003

Dendritic cells are potent antigen-presenting cells that are present in the gastrointestinal tract and are required for the induction of a Th1 T-cell acquired immune response. Since infection with the gastric pathogenHelicobacter pylorielicits a Th1 cell response, the interaction of these organisms with dendritic cells should reflect the Th1 bias. We incubatedH. pyloriwith cultured human dendritic cells and measured the cytokine induction profile, comparing the response to that induced bySalmonella entericaserovar Typhimurium. We found thatH. pyloriinduced little interleukin 6 (IL-6) and essentially no IL-10 in contrast toS. enterica.However,H. pyloriinduced levels of IL-12 that were 30% of those induced byS. enterica,indicating a Th1 response. An isogeniccagEmutant ofH. pylorilost about 50% of its IL-12-inducing ability, suggesting a role for thecagtype IV secretion system in the stimulation of dendritic cells.
Uncovering Meaning: How Nursing Knowledge Changes Policy in Practice
Authors: McLeod Emily , Spée Ria T.
Published: June 2003

What ethical values, assumptions, and beliefs guide nursing practice today? What is the purpose and intent of policy in relationship to nursing practice? What underlying assumptions, values, and beliefs are missed in policy development that is not informed by nursing knowledge? These are some of the questions the authors attempt to answer in this paper. They examine some of the ethical dilemmas that arise when nurses are required to enforce policy that conflicts with nursing theory. A description of how nursing theory informs miss-takes (that is, missed assumptions, missed understandings, missed views and values) highlights how nursing knowledge changes policy in practice.
Lingering Presence: A Study Using the Human Becoming Hermeneutic Method
Authors: Ortiz Mario R.
Published: June 2003

The purpose of this human becoming hermeneutic research was to explore the meaning of lingering presence. The emergent meanings were: (a) A lingering presence surfaces in the cherished remembered which changes moment to moment as new experiences arise in the now and shed different light on the was and will be; (b) a lingering presence is lived in private ways, yet with others in a different alone-togetherness; and (c) a lingering presence is living with the familiar-unfamiliar in the now moment, while moving beyond with different possibles. The findings are discussed in relation to how they contribute to nursing knowledge development.
Giving Voice to Persons Living With Dementia: The Researcher’s Opportunities and Challenges
Authors: Moore Theresa F. , Hollett Jane
Published: June 2003

Few qualitative studies have examined the experiences of persons living with dementia and little has been written about the opportunities and challenges for the researchers. This article challenges the assumption of dwindling personhood among persons with dementia. Methodological challenges which may be encountered by qualitative researchers are outlined and specific strategies for addressing these challenges are described including: modifying consent/assent procedures, adjusting sample size, facilitating communication, and making the most of the data.
The pattern of motor coordination underlying the roll in the lamprey
Authors: Zelenin Pavel V. , Grillner Sten , Orlovsky Grigori N. , Deliagina Tatiana G.
Published: June 2003

The lamprey swims by caudally directed lateral undulations of its body. During swimming the animal is oriented with its dorsal side up, and any deviation from this posture (roll tilt) elicits a corrective motor response aimed at restoring the normal orientation. Video recording was used to study the kinematic pattern of the response to a 90° roll tilt imposed in the intact lamprey. The corrective responses were associated with specific modifications of the swimming movements. The plane of locomotor undulations deviated from the normal, i.e. frontal plane in one direction at the beginning of the rotation and in the opposite direction at its end. A similar motor pattern was also observed in the anterior part of the body of lampreys in which the spinal cord had been transected in the mid-body area, when performing postural corrections. It could also be observed during roll turns performed by lampreys after a rostral hemisection of the spinal cord. We argue that these modifications of the locomotor pattern generate the moments of force necessary for initiation and termination of the corrective roll turn. Possible neuronal mechanisms causing the corrective movements are discussed.
Hemoglobin function in deep-sea and hydrothermal-vent endemic fish:Symenchelis parasitica(Anguillidae) andThermarces cerberus(Zoarcidae)
Authors: Weber Roy E. , Hourdez Stephane , Knowles Francis , Lallier Francois
Published: June 2003

Deep-sea hydrothermal vents probably provide the harshest physico-chemical conditions confronting metazoan animals in nature. Given the absence of information on hemoglobin (Hb) function in hydrothermal-vent vertebrates, and the complex molecular and functional adaptations observed in hydrothermal-vent invertebrates, we investigated the oxygenation reactions of Hbs from the vent-endemic zoarcid Thermarces cerberus and the deep-sea anguillid Symenchelis parasitica from adjacent habitats.

Electrophoretically cathodic and anodic isoHbs from S. parasiticaexhibit radical differences in O2 affinity and pH and organic phosphate (ATP) sensitivities, reflecting a division of labor as in other`class II' fish that express both Hb types. Remarkably, the cathodic Hb (I)lacks chloride sensitivity, and the anodic Hb (II) shows anticooperativity near half-saturation at low temperature. T. cerberus isoHbs exhibit similar affinities and pH sensitivities (`class I' pattern) but much higher O2 affinities than those observed in Hbs of the temperate,shallow-water zoarcid Zoarces viviparus, which, unless compensated,reveals markedly higher blood O2 affinities in the former species. The temperature sensitivity of O2 binding to T. cerberusHbs and the anodic S. parasitica Hb, which have normal Bohr effects,is decreased by endothermic proton dissociation, which reduces the effects of ambient temperature variations on O2 affinity. In the cathodic S. parasitica Hb, similar reduction appears to be associated with endothermic conformational changes that accompany the oxygenation reaction.
Perinuclear localization of cytosolic phospholipase A2α is important but not obligatory for coupling with cyclooxygenases
Authors: Murakami Makoto , Das Sudipto , Kim Young-Jun , Cho Wonhwa , Kudo Ichiro
Published: June 2003

In response to Ca2+ signaling, cytosolic phospholipase A2α (cPLA2α) translocates from the cytosol to the perinuclear membrane, where downstream eicosanoid‐synthetic enzymes, such as cyclooxygenase (COX), are localized. Although the spatiotemporal perinuclear colocalization of cPLA2α and COXs has been proposed to be critical for their functional coupling leading to prostanoid production, definitive evidence for this paradigm has remained elusive. To circumstantiate this issue, we took advantage of a chimeric cPLA2α mutant harboring the C2 domain of protein kinase Cα, which translocates to the plasma membrane following cell activation. Transfection analyses of the native or chimeric cPLA2α in combination with COX‐1 or COX‐2 revealed that, even though the arachidonate‐releasing capacities of native and mutant cPLA2α were comparable, prostaglandin production by mutant cPLA2α was markedly impaired as compared with that by native cPLA2α. We thus conclude that the perinuclear localization of cPLA2α is preferential, even if not obligatory, for efficient coupling with COXs.
Shock wave therapy induces neovascularization at the tendon–bone junction. A study in rabbits
Authors: Wang Ching‐Jen , Wang Feng‐Sheng , Yang Kuender D. , Weng Lin‐Hsiu , Hsu Chia‐Chen , Huang Chun‐Shun , Yang Lin‐Cheng
Published: June 2003

Despite the success in clinical application, the exact mechanism of shock wave therapy remains unknown. We hypothesized that shock wave therapy induces the ingrowth of neovascularization and improves blood supply to the tissues. The purpose of this study was to investigate the effect of shock wave therapy on neovascularization at the tendon–bone junction. Fifty New Zealand white rabbits with body weight ranging from 2.5 to 3.5 kg were used in this study. The right limb (the study side) received shock wave therapy to the Achilles tendon near the insertion to bone. The left limb (the control side) received no shock wave therapy. Biopsies of the tendon–bone junction were performed in 0, 1, 4, 8 and 12 weeks. The number of neo‐vessels was examined microscopically with hematoxylin–eosin stain. Neovascularization was confirmed by the angiogenic markers including vessel endothelial growth factor (VEGF) and endothelial nitric oxide synthase (eNOS) expressions and endothelial cell proliferation determined by proliferating cell nuclear antigen (PCNA) expression examined microscopically with immunohistochemical stains. The results showed that shock wave therapy produced a significantly higher number of neo‐vessels and angiogenesis‐related markers including eNOS, VEGF and PCNA than the control without shock wave treatment. The eNOS and VEGF began to rise in as early as one week and remained high for 8 weeks, then declined at 12 weeks; whereas the increases of PCNA and neo‐vessels began at 4 weeks and persisted for 12 weeks. In conclusion, shock wave therapy induces the ingrowth of neovascularization associated with early release of angiogenesis‐related markers at the Achilles tendon–bone junction in rabbits. The neovascularization may play a role to improve blood supply and tissue regeneration at the tendon–bone junction. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Conservation of feline semen: Part I: Cooling and freezing protocols
Authors: Luvoni G.C , Kalchschmidt E , Leoni S , Ruggiero C
Published: June 2003

There has been increased interest recently in the conservation of wild felids and preservation of valuable cat breeds. Assisted reproduction, by means of artificial insemination (AI), is an important tool for developing breeding programs for conservation. Optimal use of AI requires accurate data on semen conservation protocols and its long-term storage/survival. In this paper, semen cooling and freezing processes are described, with special emphasis on the results obtained in experiments performed in the domestic cat. Conception rates after AI in wild and domestic cats are also reported.
Effects of noradrenalin and albumin in patients with type I hepatorenal syndrome: A pilot study
Authors: Duvoux Christophe , Zanditenas David , Hézode Christophe , Chauvat Anthony , Monin Jean-Luc , Roudot-Thoraval Françoise , Mallat Ariane , Dhumeaux Daniel
Published: June 2003

Treatment of hepatorenal syndromes (HRSs) is currently based on vasopressin analogs. The aim of this pilot study was to evaluate the efficacy and safety of noradrenalin (NA) in the treatment of type 1 HRS. Between 1998 and 2000, 12 consecutive patients with type 1 HRS (7 men, 5 women; mean age, 54 ± 11 years; mean Child-Pugh score, 11.3 ± 1.7) were treated with intravenous NA (0.5-3 mg/h), in combination with intravenous albumin and furosemide. NA was given for 10 ± 3 days, at a mean dose of 0.8 ± 0.3 mg/h. Reversal of HRS was observed in 10 of 12 patients (83%; 95% confidence interval, 52%-98%) after a median of 7 days (range, 5-10 days). Serum creatinine levels fell from 358 ± 161 to 145 ± 78 μmol/L (P < .001), creatinine clearance rose from 13 ± 9 to 40 ± 15 mL/min (P = .003), and urinary sodium output increased from 8 ± 14 to 52 ± 72 mEq/d (P = .002). Changes in renal function under NA treatment were associated with an increase in mean arterial pressure (MAP; 65 ± 7 to 73 ± 9 mm Hg, P = .01) and a marked reduction in active renin (565 ± 989 to 164 ± 196 ng/L, P = .001) and aldosterone plasma concentrations (1,945 ± 1,931 to 924 ± 730 ng/mL, P = .02). There was one episode of reversible myocardial hypokinesia (in a patient on 1.5 mg/h NA) that did not recur after a dose reduction. In conclusion, NA combined with albumin and furosemide appears effective and safe for the treatment of type 1 HRS.
Jun kinase modulates tumor necrosis factor-dependent apoptosis in liver cells
Authors: Liedtke Christian , Plümpe Jörg , Kubicka Stefan , Bradham Cynthia A. , Manns Michael P. , Brenner David A. , Trautwein Christian
Published: June 2003

Tumor necrosis factor (TNF) triggers distinct pathways in liver cells through TNF receptor 1 (TNF-R1) via adapter molecules, including the intracellular cascades leading to apoptosis, nuclear factor-κB (NF-κB), and Jun kinase (JNK) activation. TNF-dependent activation of NF-κB induces the transcription of antiapoptotic genes that renders liver cells resistant against TNF-induced apoptosis. In contrast, the role of JNK during TNF-induced apoptosis is less clear, so we studied its role during this process. Hepatoma cells treated with TNF and cycloheximide undergo apoptosis, which is proceeded by a strong activation of JNK. Adenoviral vectors (adv) were tested to block TNF-dependent JNK activation selectively. An adv expressing dominant-negative (dn) TRAF2 inhibited only JNK and not ERK or NF-κB activation. However, the effect of inhibiting JNK activation with a dn TAK1 virus was also specific but was stronger than that via dn TRAF2. In further experiments, the inhibitory effect of dn TAK1 on JNK was used to define its role during TNF-dependent apoptosis. Inhibition of JNK by adv dn TAK1 resulted in an earlier and stronger induction of apoptosis. Interestingly, TAM67, a dn form of c-Jun, did not mediate the JNK-dependent effect on TNF-dependent apoptosis, indicating that other molecular targets are essential to confer this mechanism. However, the modified apoptosis pattern could be inhibited by adv expressing Bcl-2 or dn FADD. In conclusion, we define TAK1 as a kinase specifically involved in TNF-induced JNK activation in hepatoma cells and show that JNK transduces antiapoptotic signals, which modulate the strength and time course of FADD-dependent cell death involving mitochondrial permeability transfer.
Involvement of 85-kd cytosolic phospholipase A2 and cyclooxygenase-2 in the proliferation of human cholangiocarcinoma cells
Authors: Wu Tong , Han Chang , Lunz John G. , Michalopoulos George , Shelhamer James H. , Demetris Jake A.
Published: June 2003

Cyclooxygenase 2 (COX-2) and cytosolic phospholipase A2 (cPLA2) are the crucial rate-limiting enzymes in prostaglandin (PG) metabolism that show increased expression in a number of human cancers, including cholangiocarcinomas; and treatment of cholangiocarcinoma cell lines with COX-2 inhibitors can decrease proliferation. Cholangiocarcinomas also produce and proliferate in response to nonneoplastic biliary epithelial cell mitogens, such as interleukin 6 (IL-6) and hepatocyte growth factor (HGF). This study was designed to determine whether there is any relationship between eicosanoid metabolism and growth stimulation by IL-6 and HGF, two important biliary epithelial cell and cholangiocarcinoma mitogens. Incubation of SG231, a well-characterized human cholangiocarcinoma cell line, with HGF, IL-6, PGE2, or PGF2α resulted in significantly increased cell growth. HGF and IL-6 also induced a rapid release of arachidonic acid (AA) from SG231 and increased the synthesis of PGE2 and PGF2α. The cPLA2 inhibitor arachidonyl fluorophosphonate (MAFP) and the COX-2 inhibitor NS-398 significantly inhibited HGF- and IL-6-induced release of AA, PG synthesis, and proliferation in SG231 cells as well as two other human cholangiocarcinoma cell lines, HuCCT1 and CC-LP-1 cells. Thus, PGs alone can induce cholangiocarcinoma growth, and the HGF- and IL-6-induced proliferation is mediated, at least in part, by PGs. HGF and IL-6 also induced a rapid phosphorylation of cPLA2 (within 1 minute) but did not alter cPLA2 and COX-2 protein expression. The HGF- and IL-6-induced cPLA2 phosphorylation was blocked by the inhibitors of p38 and p42/44 MAP kinases, protein kinase C, calmodulin kinase, and tyrosine kinase, showing that HGF- and IL-6-induced AA release and PG production are mediated by phosphorylation of cPLA2. In conclusion, molecular pathways link classic biliary epithelial cell mitogens to PG metabolism constituents in cholangiocarcinoma growth, which may be exploited as potential therapeutic targets.
Underexpression of mRNA in human hepatocellular carcinoma focusing on eight loci
Authors: Kinoshita Moritoshi , Miyata Masahiko
Published: June 2003

Genetic alterations associated with human hepatocellular carcinoma (HCC) have been reported previously, but are not sufficient to specify differences of HCCs from precancerous diseases of the liver, such as hepatitis, hepatic fibrosis, and cirrhosis. In the present study, we performed differential gene display analysis (DGDA) to clarify the specific genetic alterations associated with gene expression changes in the course of development of HCC from chronic viral hepatitis. Four pairs of surgically resected HCCs and hepatitis tissues were investigated. We found 1,028 expression sequence tags (ESTs) that were decreased or increased in HCC tissues compared with hepatitis tissues in the same patient. Nucleotide sequencing showed that they included 55 EST clones in the GenBank database, which were considered candidates for specific messenger RNA (mRNA) expression alterations in HCCs. After excluding 9 ESTs that code mitochondrial DNA, we performed quantitative real-time reverse-transcription polymerase chain reaction (RT-PCR) for the 46 remaining EST clones. We found 8 mRNAs underexpressed in primary HCC tissues in 20 patients in higher percentages than found in previous studies, including 18 cases (90%) for aldolase B (ALDOB), 15 cases (75%) for carbamyl phosphate synthetase 1 (CPS1), albumin (ALB), plasminogen (PLG), and EST 51549, 13 cases (65%) for cytochrome P450 subfamily 2E1 (CYP2E1), 12 cases (60%) for human retinol-binding protein 4 (RBP4), and 11 cases (55%) for human organic anion transporter C (OATP-C) gene. In conclusion, underexpression of key gene products may be important in the development and/or progression of HCC.
Hepatitis E virus superinfection in patients with chronic liver disease
Authors: Hamid Saeed S. , Atiq Muslim , Shehzad Farooq , Yasmeen Aneela , Nissa Tayyabun , Salam Abdul , Siddiqui Anwar , Jafri Wasim
Published: June 2003

Infection with hepatitis A virus (HAV) can cause severe illness in adult patients with chronic liver disease (CLD) caused by hepatitis C. In endemic areas such as South Asia, however, most adult patients already have been exposed to HAV but could still be susceptible to hepatitis E virus (HEV) infection. We document that HEV superinfection in 4 of our CLD patients caused severe liver decompensation. We then determined the seroprevalence of HAV and HEV in 233 patients with stable CLD, with the goal of defining the need for protection against these viruses in these patients. Overall, 41 (17.5%) of 233 CLD patients were HEV antibody immunoglobulin G (IgG)-positive, and 228 of 233 (97.8%) were HAV IgG-positive. As controls, we tested 90 age- and sex-matched healthy volunteer blood donors for HAV and HEV antibodies IgG. There was no difference in the percentage of CLD patients and blood donors positive for HEV antibody IgG (17.7% vs. 17.5%) or for HAV IgG (97.8% vs. 94%). No differences were observed in the severity of liver disease between previously HEV-exposed and -nonexposed patients. In conclusion, superinfection with HEV in patients with underlying CLD can cause severe hepatic decompensation leading to increased morbidity and mortality. The large majority of adult CLD patients in endemic countries are vulnerable to infection with HEV, but are protected against hepatitis A, and are ideal candidates for an HEV vaccine.
Detection of a
luxS
-Signaling Molecule in
Bacillus anthracis
Authors: Jones Marcus B. , Blaser Martin J.
Published: June 2003

Quorum-sensing regulation of density-dependent genes has been described for numerous bacterial species. The partially annotated genome sequence of
Bacillus anthracis
contains an open reading frame (BA5047) predicted to encode an ortholog of
luxS
, required for synthesis of the quorum-sensing signaling molecule autoinducer-2 (AI-2). To determine whether
B. anthracis
produces AI-2, the
Vibrio harveyi
luminescence bioassay was used. Cell-free conditioned media from vaccine (Sterne) strain 34F
2
induced luminescence in
V. harveyi
reporter strain BB170, indicating its production of AI-2. Cloned BA5047, expressed in
Escherichia coli
DH5α cells, restored AI-2 activity to these cells. To evaluate whether BA5047 is essential for AI-2 synthesis, it was deleted through allelic exchange with marker rescue; the resulting mutant had no functional
luxS
activity and had reduced growth in vitro. In the wild-type strain, AI-2 activity was greatest during the exponential phase of growth. In total, these data indicate that BA5047 is a functional
luxS
ortholog in
B. anthracis
necessary for growth-phase-specific AI-2 expression. Thus,
B. anthracis
may utilize extracellular signaling molecules to regulate density-dependent gene expression.
Thioredoxin fromBrugia malayi:Defining a 16-Kilodalton Class of Thioredoxins from Nematodes
Authors: Kunchithapautham Kannan , Padmavathi B. , Narayanan R. B. , Kaliraj P. , Scott Alan L.
Published: June 2003

Thioredoxins are a family of small redox proteins that undergo NADPH-dependent reduction by thioredoxin reductase. This results in a supply of reducing equivalents that cells use in a wide variety of biological reactions, which include maintaining reduced forms of the enzymes important for protection against damage from high-energy oxygen radicals, the regulation of transcription factor activity, and the inhibition of apoptosis. Here we report on a new member of the thioredoxin family of proteins from the filarial nematodeBrugia malayi,Bm-TRX-1, which defines a new subclass of 16-kDa thioredoxins that occur widely in nematodes, includingCaenorhabditis elegans. In addition to being larger than the thioredoxins found in mammalian and bacterial species, the putative active site sequence ofBm-TRX-1, WCPPC, does not conform to the highly conserved WCGPC reported for thioredoxins from mammals to bacteria. Interestingly, an allelic form ofBm-TRX-1 was identified with an active site sequence WCPQC, which appears to be unique to the thioredoxins from filarial species.Bm-TRX-1 was between 98% and 35% identical to thioredoxins from other nematodes and ≈20% identical to the thioredoxins from mammals andEscherichia coli. Bm-TRX-1 was constitutively transcribed throughout theB. malayilife cycle, andBm-TRX protein was detectable in somatic extracts and excretory-secretory products from adults and microfilariae. RecombinantBm-TRX-1 had thiodisulfide reductase activity, as measured by the reduction of insulin, and protected DNA from the nicking activity of oxygen radicals. Overexpression ofBm-TRX-1 in a human monocyte cell line negatively regulated tumor necrosis factor alpha-induced p38 mitogen-activated protein kinase activity, suggesting a possible role of the 16-kDaBm-TRX-1 in immunomodulation.
Production of Cellulose and Curli Fimbriae by Members of the Family
Enterobacteriaceae
Isolated from the Human Gastrointestinal Tract
Authors: Zogaj Xhavit , Bokranz Werner , Nimtz Manfred , Römling Ute
Published: June 2003

Citrobacter
spp.,
Enterobacter
spp., and
Klebsiella
spp. isolated from the human gut were investigated for the biosynthesis of cellulose and curli fimbriae (
csg
). While
Citrobacter
spp. produced curli fimbriae and cellulose and
Enterobacter
spp. produced cellulose with various temperature-regulatory programs,
Klebsiella
spp. did not show pronounced expression of those extracellular matrix components. Investigation of multicellular behavior in two
Citrobacter
species and
Enterobacter sakazakii
showed an extracellular matrix, cell clumping, pellicle formation, and biofilm formation associated with the expression of cellulose and curli fimbriae. In those three strains, the
csgD-csgBA
region and the cellulose synthase gene
bcsA
were conserved. PCR screening for the presence of
csgD, csgA
and
bcsA
revealed that besides
Klebsiella pneumoniae
and
Klebsiella oxytoca,
all species investigated harbored the genetic information for expression of curli fimbriae and cellulose. Since
Citrobacter
spp.,
Enterobacter
spp., and
Klebsiella
spp. are frequently found to cause biofilm-related infections such as catheter-associated urinary tract infections, the human gut could serve as a reservoir for dissemination of biofilm-forming isolates.
Vaccine Efficacy of a Lysine Auxotroph of
Mycobacterium tuberculosis
Authors: Pavelka Martin S. , Chen Bing , Kelley Cynthia L. , Collins Frank M. , Jacobs William R.
Published: June 2003

The in vivo growth phenotype and vaccine efficacy of a lysine auxotrophic mutant of
Mycobacterium tuberculosis
strain H37Rv are described. An immunization experiment using a mouse model with an aerosol challenge showed that two doses of the
M. tuberculosis
mutant were required to generate protection equivalent to that of the
Mycobacterium bovis
BCG vaccine.
Apolipoprotein E-ε4 protects against severe liver disease caused by hepatitis C virus
Authors: Wozniak Matthew A. , Itzhaki Ruth F. , Faragher Brian E. , James Martin W. , Ryder Steven D. , Irving William L.
Published: June 2003

The outcome of infection with hepatitis C virus (HCV) varies greatly. The virus associates with serum lipoproteins, including those containing apolipoprotein E (apoE) and apolipoprotein B (apoB), and may enter cells via the low-density lipoprotein receptor (LDLR). ApoE genotypes can affect the extent of damage in diseases caused by 2 other viruses—herpes simplex virus type 1 (HSV1; in Alzheimer’s disease and herpes labialis) and human immunodeficiency virus (HIV). We therefore investigated whether specific apoE and apoB alleles were associated with different outcomes of HCV infection. A total of 156 anti-HCV-positive patients and 104 non-HCV-infected patients were studied. Liver biopsy specimens from patients with chronic HCV infection (n = 111) were assessed for disease severity by the Knodell system. ApoE and apoB genotypes were determined by standard polymerase chain reaction (PCR) methods. There was no significant difference among the apoE genotypes of HCV-infected subjects compared with previously published population data, or between HCV-RNA positive or negative patients. However, chronically HCV-infected subjects with mild liver disease (n = 65) had a significantly higher apoE-ε4 allele frequency (20.0%) than those (n = 46) with severe disease (6.5%). ApoB alleles alone or in combination with apoE were not associated with mild or severe disease. The overall apoE allele frequencies of patients with liver disease not caused by HCV were similar to those of the total HCV group and in contrast to the HCV patients, the apoE allele frequencies were similar in those patients with no or mild fibrosis as compared with those with bridging fibrosis or cirrhosis. In conclusion, carriage of an apoE-ε4 allele may be protective against liver damage caused by HCV, but not against damage due to various nonviral causes. This is yet another case in which apoE may determine the severity of a viral disease.
Candida albicans
Septin Mutants Are Defective for Invasive Growth and Virulence
Authors: Warenda Amy J. , Kauffman Sarah , Sherrill Taylor P. , Becker Jeffrey M. , Konopka James B.
Published: June 2003

Hyphal growth of
Candida albicans
is implicated as an important virulence factor for this opportunistic human pathogen. Septin proteins, a family of cytoskeletal elements that regulate membrane events and are important for proper morphogenesis of
C
.
albicans
, were examined for their role in tissue invasion and virulence in the mouse model of systemic infection. In vitro, septin mutants are only mildly defective for hyphal growth in liquid culture but display pronounced defects for invasive growth into agar. In vivo, the septin mutants were found to exhibit attenuated virulence. However, mice infected with the mutants displayed high fungal burdens in their kidneys without obvious symptoms of disease. Histological examination of infected kidneys revealed defects in organ invasion for the
cdc10Δ
and
cdc11Δ
deletion mutants, which displayed both reduced tissue penetration and noninvasive fungal masses. Thus, the septin proteins are necessary for invasive growth, which appears to be more important to the successful pathogenesis of
C
.
albicans
than hyphal growth alone.
CD44-Regulated Intracellular Proliferation ofListeria monocytogenes
Authors: Eriksson Emma , Dons Lone , Rothfuchs Antonio Gigliotti , Heldin Paraskevi , Wigzell Hans , Rottenberg Martin E.
Published: June 2003

CD44 has been implicated in immune and inflammatory processes. We have analyzed the role of CD44 in the outcome ofListeria monocytogenesinfection in murine bone marrow-derived macrophages (BMM). Surprisingly, a dramatically decreased intracellular survival ofL. monocytogeneswas observed in CD44−/−BMM. CD44−/−heart or lung fibroblast cultures also showed reduced bacterial levels. Moreover, livers from CD44−/−-infected mice showed diminished levels ofL. monocytogenes. In contrast, intracellular growth ofSalmonella entericaserovar Typhimurium was the same in CD44−/−and control BMM. The CD44-mediated increased bacterial proliferation was not linked to altered BMM differentiation or to secretion of soluble factors. CD44 did not mediate listerial uptake, and it played no role in bacterial escape from the primary phagosome or formation of actin tails. Furthermore, CD44-enhanced listerial proliferation occurred in the absence of intracellular bacterial spreading. Interestingly, coincubation of BMM with hyaluronidase or anti-CD44 antibodies that selectively inhibit hyaluronan binding increased intracellular listerial proliferation. Treatment of cells with hyaluronan, in contrast, diminished listerial growth and induced proinflammatory transcript levels. We suggest thatL. monocytogenestakes advantage of the CD44-mediated signaling to proliferate intracellularly, although binding of CD44 to certain ligands will inhibit such response.
Bordetella bronchiseptica
Persists in the Nasal Cavities of Mice and Triggers Early Delivery of Dendritic Cells in the Lymph Nodes Draining the Lower and Upper Respiratory Tract
Authors: Gueirard Pascale , Ave Patrick , Balazuc Anne-Marie , Thiberge Sabine , Huerre Michel , Milon Genevieve , Guiso Nicole
Published: June 2003

Early after the intranasal instillation of
Bordetella bronchiseptica
into mice, not only are mature dendritic leukocytes recovered from lung parenchyma and bronchoalveolar lavage fluid but their numbers are also increased in the mediastinal lymph nodes and the nasal mucosa-associated lymphoid tissue. Later during the infectious process, the bacteria persist mainly in the nasal cavity.
The σ
B
Regulon Influences Internalization of
Staphylococcus aureus
by Osteoblasts
Authors: Nair Sean P. , Bischoff Markus , Senn Maria M. , Berger-Bächi Brigitte
Published: June 2003

Individual strains of
Staphylococcus aureus
have different capacities to become internalized by osteoblasts. Here we report that the levels of σ
B
expressed by
S
.
aureus
correlate with the capacity of this bacterium to be internalized by osteoblasts. However, σ
B
is not essential for internalization and does not necessarily account for the differences in the capacities of strains to be internalized.
Inhibition of Hepatic Stellate Cell Proliferation and Activation by the Semisynthetic Analogue of Fumagillin Tnp–470 in Rats
Authors: Wang Yan Qing , Ikeda Kazuo , Ikebe Takashi , Hirakawa Kosei , Sowa Michio , Nakatani Kazuki , Kawada Norifumi , Kaneda Kenji
Published: June 2003

Proliferation and activation of hepatic stellate cells (HSCs) are critical steps for the development of postnecrotic fibrosis in the liver. The present study aimed to reveal the inhibitory effect of the semisynthetic analogue of fumagillin TNP–470 on these events for its possible use as an antifibrogenic agent. Rat models of carbon tetrachloride (CCl4)– and dimethylnitrosamine–induced hepatic fibrosis were used for anin vivostudy. In both models, the fibrotic area was considerably decreased by concurrent repetitive subcutaneous injections of 30 mg/kg body weight of TNP–470. In CCl4–induced fibrosis, factor VIII–related antigen–positive blood vessels, desmin–, or α–smooth muscle actin (αSMA)–positive mesenchymal cells, bromodeoxyuridine (BrdU)–positive mesenchymal cells also decreased in number by treatment with TNP–470. Inin vitroexperiments, a supplement of 1,000 ng/mL TNP–470 suppressed BrdU incorporation and cyclins D1, D2, and E expression by cultured HSCs in the absence and/or presence of platelet–derived growth factor (PDGF). Expression of HSC activation markers,i.e., αSMA and PDGF receptor β, was also suppressed. The present results indicate that TNP–470 inhibits HSC proliferation by blocking the cell–cycle transition from G1 to S and HSC activation, and, as the consequence, prevents the progression of hepatic fibrosis, probably being coupled with its antiangiogenic effect.
The Hemodynamic Response to Medical Treatment of Portal Hypertension As A Predictor of Clinical Effectiveness in the Primary Prophylaxis of Variceal Bleeding in Cirrhosis
Authors: Merkel Carlo , Bolognesi Massimo , Sacerdoti David , Bombonato Giancarlo , Bellini Barbara , Bighin Raffaella , Gatta Angelo
Published: June 2003

In the prevention of variceal rebleeding, it is already established that hemodynamic response to drug treatment (decrease in hepatic venous pressure gradient [HVPG] to 12 mm Hg or by >20%) is predictive of clinical effectiveness. In primary prophylaxis very few clinical data are available. We assessed the role of the hemodynamic response to beta–blockers or beta–blockers plus nitrates in predicting clinical efficacy of prophylaxis. A total of 49 cirrhotic patients with varices at risk of bleeding, without prior variceal bleeding, were investigated by hepatic vein catheterization before and after 1 to 3 months of chronic treatment with nadolol or nadolol plus isosorbide mononitrate, and were followed during treatment for up to 5 years. A total of 30 patients (61%) were good hemodynamic responders, and among them in 12 (24%) HVPG was ≤12 mm Hg during treatment. During treatment 9 patients had variceal bleeding: 7 were poor responders and 2 were good responders. The probability of bleeding at 3 years of follow–up was significantly higher in poor responders (41%) than in good responders (7%;P= .0008). No patient reaching an HVPG of 12 mm Hg or less during treatment had variceal bleeding during follow–up. Cox's regression analysis showed that poor hemodynamic response was the main factor predicting bleeding (β = 1.91; SE(β) = 0.80;P= .01). During follow–up 11 patients died of hepatic causes. Survival was related to Child–Pugh class and to initial value of HVPG, according to Cox's analysis. In conclusion, the assessment of hemodynamic response to drugs in terms of HVPG is the best predictor of efficacy of prophylaxis of variceal bleeding in patients treated with beta–blockers or beta–blockers plus nitrates.
The clinical importance of adrenal insufficiency in acute hepatic dysfunction
Authors: Harry Rachael , Auzinger Georg , Wendon Julia
Published: June 2003

Acute liver failure and septic shock share many clinical features, including hyperdynamic cardiovascular collapse. Adrenal insufficiency may result in a similar cardiovascular syndrome. In septic shock, adrenal insufficiency, defined using the short synacthen test (SST), is associated with hemodynamic instability and poor outcome. We examined the SST, a dynamic test of adrenal function, in 45 patients with acute hepatic dysfunction (AHD) and determined the association of these results with hemodynamic profile, severity of illness, and outcomes. Abnormal SSTs were common, occurring in 62% of patients. Those who required noradrenaline (NA) for blood pressure support had a significantly lower increment (median, 161 vs. 540 nmol/L; P < .001) following synacthen compared with patients who did not. Increment and peak were lower in patients who required ventilation for the management of encephalopathy (increment, 254 vs. 616 nmol/L, P < .01; peak, 533 vs. 1,002 nmol/L, P < .01). Increment was significantly lower in those who fulfilled liver transplant criteria compared with those who did not (121 vs. 356 nmol/L; P < .01). Patients who died or underwent liver transplantation had a lower increment (148 vs. 419 nmol/L) and peak (438 vs. 764 nmol/L) than those who survived (P < .01). There was an inverse correlation between increment and severity of illness (Sequential Organ Failure Assessment, r = −0.63; P < .01). In conclusion, adrenal dysfunction assessed by the SST is common in AHD and may contribute to hemodynamic instability and mortality. It is more frequent in those with severe liver disease and correlates with severity of illness.
Normal hepatocytes correct serum bilirubin after repopulation of Gunn rat liver subjected to irradiation/partial resection
Authors: Guha Chandan , Parashar Bhupesh , Deb Niloy J. , Garg Madhur , Gorla Giridhar R. , Singh Anupam , Roy-Chowdhury Namita , Vikram Bhadrasain , Roy-Chowdhury Jayanta
Published: June 2003

The treatment of inherited metabolic liver diseases by hepatocyte transplantation (HT) would be greatly facilitated if the transplanted normal hepatocytes could be induced to proliferate preferentially over the host liver cells. We hypothesized that preparative hepatic irradiation (HIR) should inhibit host hepatocyte proliferation in response to partial hepatectomy (PH). Normal nonirradiated hepatocytes transplanted in this setting should have a selective growth advantage over the host liver cells and should progressively repopulate the liver. To test this hypothesis, we transplanted 5 million hepatocytes from normal Wistar-Roman High Avoidance (RHA) rats into the livers of congeneic bilirubin-uridine 5’-diphosphoglucuronate glucuronosyltransferase (UGT1A1)-deficient jaundiced Gunn rats by intrasplenic injection after one of the following treatments: (1) 68% PH, (2) HIR (50 Gy), or (3) HIR + PH. In rats receiving either PH or HIR alone before HT, serum bilirubin concentrations declined by 25% to 30% in 28 weeks. In contrast, serum bilirubin levels were normalized completely in rats receiving HIR + PH before HT. Massive repopulation of the Gunn rat liver by the UGT1A1-positive Wistar-RHA hepatocytes was shown by UGT1A1 enzyme assay, immunoblot analysis, and immunohistochemical staining of the recipient liver. High-performance liquid chromatography analysis of the bile collected from Gunn rats 5 months after PH, HIR, and HT showed normalization of the pigment profile, with bilirubin diglucuronide and monoglucuronide as the predominant pigments. In conclusion, a preparative regimen of HIR + PH results in massive repopulation of the liver with functionally normal transplanted hepatocytes, resulting in complete correction of a metabolic deficiency. Noninvasive strategies to replace PH for providing proliferative stimuli to the transplanted cells should make this regimen valuable in augmenting the effects of HT for the treatment of liver diseases.
Hepatocytes undergo phenotypic transformation to biliary epithelium in organoid cultures
Authors: Michalopoulos George K. , Bowen William C. , Mulè Karen , Lopez-Talavera Juan Carlos , Mars Wendy
Published: June 2003

Organoid cultures of hepatocytes in the presence of hepatocyte growth factor (HGF) and epidermal growth factor (EGF) display characteristic histologic organization. Biliary epithelium covers the surface of the tissue exposed to the culture medium. Hepatocytes, stellate cells and endothelial cells compose the underlying structures. In order to investigate the origin of the biliary epithelial cells in the organoid cultures, we utilized the retrorsine/DPPIV system of hepatocyte transplantation to create hybrid livers in which clones of DPPIV hepatocytes colonize variable portions of the lobules. We demonstrate that, as others have shown, biliary epithelium in this in vivo system remains that of the recipient (DPPIV negative) rat. Hepatocytes are the only cells positive for the DPPIV marker enzyme in the hybrid livers. Organoid cultures were prepared from the hybrid livers. Overall, 46.82% of the hepatocytes placed into culture were positive for DPPIV at time zero (after isolation). At 21 days in culture, 47.54% of the biliary epithelium on the surface of the organoid cultures was positive for DPPIV. Since the only DPPIV cells inoculated in the cultures were hepatocytes, this finding demonstrates that, in the conditions of the organoid cultures, hepatocytes do undergo phenotypic transition to biliary epithelial cells.
Selective mitochondrial glutathione depletion by ethanol enhances acetaminophen toxicity in rat liver
Authors: Zhao Ping , Kalhorn Thomas F. , Slattery John T.
Published: June 2003

Chronic alcohol consumption may potentiate acetaminophen (APAP) hepatotoxicity through enhanced formation of N-acetyl-p-benzoquinone imine (NAPQI) via induction of cytochrome P450 2E1 (CYP2E1). However, CYP2E1 induction appears to be insufficient to explain the claimed magnitude of the interaction. We assessed the role of selective depletion of liver mitochondrial glutathione (GSH) by chronic ethanol. Rats were fed the Lieber-DeCarli diet for 10 days or 6 weeks. APAP toxicity in liver slices (% glutathione-S-transferase α released to the medium, GST release) and NAPQI toxicity in isolated liver mitochondria (succinate dehydrogenase inactivation, SDH) from these rats were compared with pair-fed controls. Ethanol induced CYP2E1 in both the 10-day and 6-week groups by ˜2-fold. APAP toxicity in liver slices was higher in the 6-week ethanol group than the 10-day ethanol group. Partial inhibition of NAPQI formation by CYP2E1 inhibitor diethyldithiocarbamate to that of pair-fed controls abolished APAP toxicity in the 10-day ethanol group only. Ethanol selectively depleted liver mitochondrial GSH only in the 6-week group (by 52%) without altering cytosolic GSH. Significantly greater GSH loss and APAP covalent binding were observed in liver slice mitochondria of the 6-week ethanol group. Isolated mitochondria of the 6-week ethanol group were ˜50% more susceptible to NAPQI (25-165 μmol/L) induced SDH inactivation. This increased susceptibility was reproduced in pair-fed control mitochondria pretreated with diethylmaleate. In conclusion, 10-day ethanol feeding enhances APAP toxicity through CYP2E1 induction, whereas 6-week ethanol feeding potentiates APAP hepatotoxicity by inducing CYP2E1 and selectively depleting mitochondrial GSH.
Role of transarterial chemoembolization before liver resection for hepatocarcinoma
Authors: Gerunda Giorgio Enrico , Neri Daniele , Merenda Roberto , Barbazza Franco , Zangrandi Fabio , Meduri Francesco , Bisello Marco , Valmasoni Michele , Gangemi Antonio , Faccioli Alvise Maffei
Published: June 2003

The aim of this study was to clarify whether chemoembolization (TACE) before liver resection (LR) can reduce postoperative hepatocellular carcinoma (HCC) recurrence and improve disease-free and overall survival. Eighty-nine patients with tumor-stage (TNM) I-II HCC were evaluated for LR. Patients were prospectively allocated to LR alone or TACE plus LR based on their place of residence. Twenty nonlocal patients (24%) were selected for LR, while 69 (77.5%) local patients were selected for TACE plus LR. Following TACE, the tumor stage could be confirmed in only 20 patients (29%) who then underwent LR. Operative mortality was 0%, but in the TACE-LR group, 3 patients died of liver failure between 2 and 5 months after surgery. Early recurrence (<24 months) was 59% for LR versus 20% for TACE plus LR (P < .05). Late recurrence was 18% for LR versus 10% for TACE plus LR (P = not significant [NS]). The overall recurrence rate was 76% for LR versus 30% for TACE plus LR (P < .02). Death due to HCC recurrence was 70% for LR versus 15% for TACE plus LR (P < .05). The overall 1- and 5-year survival rates did not differ significantly (71% to 38% for LR v 85% to 43% for TACE + LR; P = NS), whereas the difference in 1- and 5-year disease-free survival was highly significant (64% to 21% for LR v 82% to 57% for TACE + LR; P < .02). TACE was able to improve the HCC staging process and significantly reduce the incidence of early and overall HCC recurrence and related death after LR; it improved the disease-free interval, but not the overall survival, due to an increase in liver failure in the first 5 months.