bluuebunny/crossref_metadata_2025_split huggingface dataset:
Subcutaneous and continuous administration of lipopolysaccharide increases serum levels of triglyceride and monocyte chemoattractant protein‐1 in rats
Authors: Uchiumi D. , Kobayashi M. , Tachikawa T. , Hasegawa K. 
Published: February 2004

Objectives:  Previous studies have suggested an association between chronic infection and cardiovascular disease, and combined infection/inflammation is frequently related with hypertriglyceridemia, which may be a risk factor of cardiovascular disease. In fact, experimental transient or intermittent administration of lipopolysaccharide (LPS) is known to cause hypertriglyceridemia. We investigated the effects of subcutaneous and continuous administration of LPS in rats, which was considered to mimic chronic infection such as periodontal disease, on the serum levels of lipids [triglyceride (TG), total cholesterol (TC) and free fatty acid (FFA)] and cytokines [tumor necrosis factor‐α (TNF‐α) and monocyte chemoattractant protein‐1 (MCP‐1)], all of which are thought to be etiological factors of atherosclerotic cardiovascular disease.Methods:  Ten fasted Wistar rats were subcutaneously injected with LPS (500 µg/100 g of body weight) (LPS‐injected rats; n = 5) or saline (saline‐injected rats; n = 5) as a model of transient infection. Further, mini‐osmotic pumps containing the same concentration of LPS (LPS‐implanted rats; n = 5) or saline (saline‐implanted rats; n = 5) were subcutaneously implanted into an additional 10 rats as a model of chronic infection. After the injection or implantation, time‐dependent changes in serum levels of TG, TC, FFA, TNF‐α, MCP‐1 and LPS were determined.Results:  LPS was detected in serum until 24 h in LPS‐injected rats and until day 5 in LPS‐implanted rats. Serum TG levels significantly increased from 6 to 24 h in LPS‐injected rats and from day 5 to 14 in LPS‐implanted rats. In both LPS‐injected and LPS‐implanted rats, serum FFA levels increased only slightly, whereas serum TC levels did not appreciably change. Both types of LPS administration increased serum TNF‐α levels transiently and MCP‐1 levels continuously.Conclusions:  These findings suggest that chronic infection such as periodontal disease induces hypertriglyceridemia and increases serum MCP‐1 levels in a manner that increases the risk of atherosclerotic cardiovascular disease.
Effect of low dose Actinobacillus actinomycetemcomitans lipopolysaccharide pretreatment on cytokine production by human whole blood
Authors: Nakamura Tsutomu , Nitta Hiroshi , Ishikawa Isao 
Published: February 2004

Background and objective:  Periodontal disease is known to influence the systemic condition in various ways, and the bacteria and their products, such as lipopolysaccharides (LPS), may spread from periodontal lesions via the systemic circulation to affect distant organs. The level of LPS in plasma from such patients is reported to be very low, and this low level of LPS is suspected to have priming or desensitizing effect. Thus, we investigated the effects of low dose LPS pretreatment on LPS‐dependent cytokine production by whole blood cells ex vivo.Methods:  Blood samples obtained from seven systemically and periodontally healthy individuals were pretreated with or without 5 pg/ml Actinobacillus actinomycetemcomitans LPS, followed by further stimulation with 1 ng/ml A. actinomycetemcomitans LPS. The concentrations of interleukin‐1 beta (IL‐1β), IL‐6, IL‐10 and tumor necrosis factor‐alpha (TNF‐α) in the culture supernatants were then determined using enzyme‐linked immunosorbent assay (ELISA). In addition, intracytoplasmic cytokine staining of whole blood cells was performed for flow cytometry.Results:  Pretreatment with 5 pg/ml A. actinomycetemcomitans LPS significantly enhanced the production of IL‐1β and IL‐6 from whole blood when further induced by 1 ng/ml LPS (1.72 times higher for IL‐1β, 2.18 times higher for IL‐6 than without pretreatment). The pretreatment did not enhance the production of either TNF‐α or IL‐10. Intracytoplasmic staining showed that the monocyte fraction was primarily involved in producing IL‐1β and IL‐6. Flow cytometric analysis revealed that pretreatment increased the number of IL‐1β and IL‐6 producing cells as well as mean fluorescence intensity of the stained cells.Conclusion:  A low dose of bloodstream LPS found in periodontitis patients appears to be sufficient to prime monocytes, and may be capable of affecting the systemic responses of immune and inflammatory cells.
Variations of Porphyromonas gingivalis fimbriae in relation to microbial pathogenesis
Authors: Amano Atsuo , Nakagawa Ichiro , Okahashi Nobuo , Hamada Nobushiro 
Published: February 2004

Objectives:  Periodontal disease is an infectious disorder caused by a small subset of periodontal pathogens including Porphyromonas gingivalis. Accumulated evidences show that the expression of P. gingivalis heterogenic virulence properties is dependent on its clonal diversity. P. gingivalis expresses two distinct fimbria molecules, major and minor fimbriae, on its cell surfaces, both of which seem to be involved in the development of periodontitis. In this short review, variations of fimbriae in relation to microbial pathogenesis are discussed.Materials and Methods:  Our recent findings are summarized to elucidate the relationship between clonal variation of fimbriae and bacterial pathogenicity of various strains.Results:  Major fimbriae were classified into six types (I to V and Ib) based on the diversity of fimA genes encoding FimA (a subunit of major fimbriae). A majority of periodontitis patients were found to carry type II fimA organisms, followed by type IV, and type II fimA organisms were significantly occurred with more severe forms of periodontitis. Studies of clones with type II fimA have revealed significantly greater adhesive and invasive capabilities to epithelial cells than other fimA type clones. Minor fimbriae induced interleukin‐1α (IL‐1α), IL‐1β, IL‐6, and tumor necrosis factor‐α (TNF‐α) cytokine expression in macrophages and were suggested to be a causative factor of alveolar bone resorption in animal models. The clonal diversity of minor fimbriae is unclear, however, distinct minor fimbria molecules were found in different strains.Conclusion:  The fimbria variations may have an influence on the development of periodontal disease.
Role of MyD88 in Diminished Tumor Necrosis Factor Alpha Production by Newborn Mononuclear Cells in Response to Lipopolysaccharide
Authors: Yan Sen Rong , Qing Gefei , Byers David M. , Stadnyk Andrew W. , Al-Hertani Walla , Bortolussi Robert 
Published: February 2004

ABSTRACTHuman newborns are more susceptible than adults to infection by gram-negative bacteria. We hypothesized that this susceptibility may be associated with a decreased response by leukocytes to lipopolysaccharide (LPS). In this study, we compared LPS-induced secretion of tumor necrosis factor alpha (TNF-α) by mononuclear cells (MNC) from adult peripheral blood and newborn umbilical cord blood in vitro and attempted to determine the mechanisms involved in its regulation. At a high concentration of LPS (10 ng/ml) and in the presence of autologous plasma, MNC from adults and newborns secreted similar amounts of TNF-α. However, in the absence of plasma, MNC from newborns secreted significantly less TNF-α compared to MNC from adults. Moreover, at a low concentration of LPS (0.1 ng/ml) and in the presence of plasma, TNF-α secretion was significantly lower for newborn MNC compared to adult MNC. Adults and newborns had similar numbers of CD14 and Toll-like receptor 4 (TLR-4)-positive cells as measured by flow cytometry. However, the intensity of the CD14 marker was greater for adult than for newborn cells. Incubation of cells with LPS led to an increase in CD14 and TLR-4 intensity for adult cells but not for newborn cells. The effect of LPS stimulation of adult or newborn cells was similar for ERK, p38, and IκBα phosphorylation, as well as IκBα degradation. Finally, we assessed levels of the TLR-4 adapter protein, the myeloid differentiation antigen 88 (MyD88). We found a direct relation between adult and newborn TNF-α secretion and MyD88, which was significantly decreased in newborn monocytes. Since TLR-4 signals intracellularly through the adapter protein, MyD88, we hypothesize that MyD88-dependent factors are responsible for delayed and decreased TNF-α secretion in newborn monocytes.
Contribution of Long Polar Fimbriae to the Virulence of Rabbit-Specific Enteropathogenic
Escherichia coli
Authors: Newton Hayley J. , Sloan Joan , Bennett-Wood Vicki , Adams Louise M. , Robins-Browne Roy M. , Hartland Elizabeth L. 
Published: February 2004

ABSTRACT

Enteropathogenic
Escherichia coli
(EPEC) is a major of cause of diarrhea among children in developing countries. Although EPEC is a human specific pathogen, some related strains are natural pathogens of animals, including laboratory-bred rabbits. We have identified two chromosomal loci in rabbit-specific EPEC (REPEC) O15:H− strain 83/39, which are predicted to encode long polar fimbriae (LPF).

lpf
R154

was identical to a fimbrial gene cluster,

lpf
O113

, identified previously in enterohemorrhagic
E. coli
(EHEC) O113:H21. The second locus,

lpf
R141

, comprised a novel sequence with five predicted open reading frames,
lpfA
to
lpfE
, that encoded long fine fimbriae in nonfimbriated
E. coli
ORN103. The predicted products of

lpf
R141

shared identity with components of the
lpfABCC′DE
gene cluster from EHEC O157:H7, and the fimbriae were similar in morphology and length to LPF from EHEC O157:H7. Interruption of

lpf
R141

resulted in significant attenuation of REPEC 83/39 for rabbits with respect to the early stages of colonization and severity of diarrhea. However, there was no significant difference in the number of bacteria shed at later time points or in overall body weight and mortality rate of rabbits infected with

lpf
R141

mutant strains or wild-type REPEC 83/39. Although rabbits infected with the

lpf
R141

mutants did not develop severe diarrhea, there was evidence of attaching and effacing histopathology, which was indistinguishable in morphology, location, and extent compared to rabbits infected with wild-type REPEC 83/39. The results suggested that

lpf
R141

contributes to the early stages of REPEC-mediated disease and that this is important for the development of severe diarrhea in susceptible animals.
A Type III Secretion System Is Required for
Aeromonas hydrophila
AH-1 Pathogenesis
Authors: Yu H. B. , Rao P. S. Srinivasa , Lee H. C. , Vilches S. , Merino S. , Tomas J. M. , Leung K. Y. 
Published: February 2004

ABSTRACT

Aeromonas hydrophila
is a gram-negative opportunistic pathogen in fish and humans. Many bacterial pathogens of animals and plants have been shown to inject anti-host virulence determinants into the hosts via a type III secretion system (TTSS). Degenerate primers based on
lcrD
family genes that are present in every known TTSS allowed us to locate the TTSS gene cluster in
A. hydrophila
AH-1. A series of genome walking steps helped in the identification of 25 open reading frames that encode proteins homologous to those in TTSSs in other bacteria. PCR-based analysis showed the presence of
lcrD
homologs (
ascV
) in all of the 33 strains of
A. hydrophila
isolated from various sources. Insertional inactivation of two of the TTSS genes (
aopB
and
aopD
) led to decreased cytotoxicity in carp epithelial cells, increased phagocytosis, and reduced virulence in blue gourami. These results show that a TTSS is required for
A. hydrophila
pathogenesis. This is the first report of sequencing and characterization of TTSS gene clusters from
A. hydrophila
. The TTSS identified here may help in developing suitable vaccines as well as in further understanding of the pathogenesis of
A. hydrophila
.
A 38-Kilobase Pathogenicity Island Specific forMycobacterium aviumsubsp.paratuberculosisEncodes Cell Surface Proteins Expressed in the Host
Authors: Stratmann Janin , Strommenger Birgit , Goethe Ralph , Dohmann Karen , Gerlach Gerald-F. , Stevenson Karen , Li Ling-ling , Zhang Qing , Kapur Vivek , Bull Tim J. 
Published: February 2004

ABSTRACTWe have used representational difference analysis to identify a novelMycobacterium aviumsubsp.paratuberculosis-specific ABC transporter operon (mpt), which comprises six open reading frames designatedmptAto -Fand is immediately preceded by two putative Fur boxes. Functional genomics revealed that themptoperon is flanked on one end by afepcluster encoding proteins involved in the uptake of Fe3+and on the other end by asidcluster encoding non-ribosome-dependent heterocyclic siderophore synthases. Together these genes form a 38-kbM. aviumsubsp.paratuberculosis-specific locus flanked by an insertion sequence similar to IS1110. Expression studies using Western blot analyses showed that MptC is present in the envelope fraction ofM. aviumsubsp.paratuberculosis. The MptD protein was shown to be surface exposed, using a specific phage (fMptD) isolated from a phage-peptide library, by differential screening ofMycobacterium smegmatistransformants. The phage fMptD-derived peptide could be used in a peptide-mediated capture PCR with milk from infected dairy herds, thereby showing surface-exposed expression of the MptD protein in the host. Together, these data suggest that the 38-kb locus constitutes anM. aviumsubsp.paratuberculosispathogenicity island.
Purification and Analysis of a Phospholipase A2-Like Lytic Factor ofTrichomonas vaginalis
Authors: Lubick Kirk J. , Burgess Donald E. 
Published: February 2004

ABSTRACTTrichomonas vaginalisproduces soluble factors that have been reported to have the ability to damage target cells in vitro, and it has been hypothesized that these factors may play a role in the pathogenesis of human trichomoniasis. A lytic factor (LF) was purified fromT. vaginalis, and the molecular characteristics of LF were determined.T. vaginalisextract was subjected to hydrophobic chromatography with a 10 to 60%N-propanol gradient in 0.1 M ammonium acetate, resulting in the elution of LF from the column at 30%N-propanol. Cytotoxicity assays revealed that LF was cytotoxic to WEHI 164 cells and bovine red blood cells, and inactivation of LF by treatment with trypsin suggested that the active component of LF was a protein. Size exclusion chromatography of LF produced two fractions at 144 and 168 kDa, and analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of LF under reducing conditions revealed two subunits of 57 and 60 kDa. Results of a fluorescence assay of LF on carboxyfluorescein-labeled liposomes composed of phosphatidylcholine-cholesterol showed that liposomes were hydrolyzed, suggesting that LF had phospholipase activity. Thin-layer chromatography analysis of BODIPY (4,4-difluoro-3a,4adiaza-s-indacene)-labeled phosphatidylcholine treated with LF demonstrated products that migrated identically to the products produced by treatment with phospholipase A2(PLA2). These results suggest that LF is a PLA2and may be an important virulence factor ofT. vaginalismediating the destruction of host cells and contributing to tissue damage and inflammation in trichomoniasis.
Lutzomyia longipalpisSalivary Gland Homogenate Impairs Cytokine Production and Costimulatory Molecule Expression on Human Monocytes and Dendritic Cells
Authors: Costa Dirceu J. , Favali Cecília , Clarêncio Jorge , Afonso Lílian , Conceição Viviane , Miranda José Carlos , Titus Richard G. , Valenzuela Jesus , Barral-Netto Manoel , Barral Aldina , Brodskyn Cláudia Ida 
Published: February 2004

ABSTRACTIn this report, we describe an investigation of the effects ofLutzomyia longipalpissand fly salivary gland homogenates (SGH) on cytokine production and expression of costimulatory molecules on human monocytes, macrophages (Mφs), and dendritic cells (DCs). SGH ofL. longipalpisinduced an increase in interleukin-6 (IL-6), IL-8 and IL-12p40 production but a decrease in tumor necrosis factor alpha and IL-10 production by lipopolysaccharida (LPS)-stimulated monocytes. We also examined the expression of costimulatory molecules on the surface of monocytes, Mφs, and DCs. Whereas SGH affected the expression of these molecules on monocytes and Mφs, it had little effect on these molecules on DCs. However, when DCs were generated from human monocytes in the presence of SGH, SGH inhibited the expression of costimulatory molecules. In addition, a decrease in the maturation of DCs induced by CD40L was observed in the presence of SGH. Finally, preincubating SGH with human sera containing anti-SGH-specific antibodies abolished the effects of SGH on cytokine production by LPS-stimulated monocytes.
Cryptosporidium parvum-Specific CD4 Th1 Cells from Sensitized Donors Responding to Both Fractionated and Recombinant Antigenic Proteins
Authors: Morales Maria Angeles Gomez , Mele Raffaella , Ludovisi Alessandra , Bruschi Fabrizio , Tosini Fabio , Pozio Edoardo 
Published: February 2004

ABSTRACTT-cell-mediated immunity plays a central role in the host response toCryptosporidium parvum. Human T-cell clones (TCC) were isolated from peripheral blood mononuclear cells of five healthy donors with prior cryptosporidiosis by use of aC. parvumcrude extract, two antigen fractions obtained by ion-exchange chromatography (IEC1 and IEC2), and two recombinant peptides (SA35 and SA40) fromC. parvumsporozoites. The T-cell lines derived from the one recently infected donor had a higher proportion (26 to 38%) of T cells exhibiting the γ/δ T-cell receptor (γ/δ-TCR) than those from donors who had recovered from cryptosporidiosis several years earlier, suggesting that the γ/δ T-cell population is involved in the early stage of the infection. The specific TCC had the α/β-TCR, had the phenotype CD45RO+CD4+CD8−, and were characterized by either hyperproduction of gamma interferon (IFN-γ) alone, with a Th1 profile, or IFN-γ hyperproduction together with interleukin-4 (IL-4) or IL-5 production, with a Th0 profile. SA35, SA40, IEC1, and IEC2 may be considered good targets of the cellular response againstC. parvumand may play a role in maintaining the T-cell-mediated memory response to this parasite. Furthermore, the SA35 and SA40 peptides may be regarded as immunodominant antigens involved in the maintenance of the T-cell response in healthyC. parvum-sensitized persons.
Production of Interleukin-8 by Human Neutrophils Stimulated with
Trichomonas vaginalis
Authors: Ryu Jae-Sook , Kang Ji-Hyun , Jung Seung-Yong , Shin Myeong-Heon , Kim Jung-Mogg , Park Hyun , Min Duk-Young 
Published: February 2004

ABSTRACT

Neutrophils are the predominant inflammatory cells found in the vaginal discharges of patients infected with
Trichomonas vaginalis
. Although chemoattractants, such as leukotriene B
4
and interleukin-8 (IL-8), are found in the vaginal discharges of symptomatic trichomoniasis patients, little is known about the mechanism of how neutrophils accumulate or mediate initial inflammatory response after acute
T. vaginalis
infection. We examined IL-8 production in neutrophils activated by
T. vaginalis
and evaluated the factors involved in
T. vaginalis
adherence that might affect IL-8 production. When human neutrophils were stimulated with live trophozoites,
T. vaginalis
lysate, or
T. vaginalis
excretory-secretory products, the live trichomonads induced higher levels of IL-8 production than the lysate or products did. When live trichomonads were pretreated with various inhibitors of proteinase, microtubule, microfilament, or adhesin (which are all known to participate in the adherence of
T. vaginalis
to vaginal epithelial cells), IL-8 production significantly decreased compared with the untreated controls. Furthermore, an NF-κB inhibitor (pyrrolidine dithiocarbamate), a mitogen-activated protein (MAP) kinase (MEK) inhibitor (PD98059), and a p38 MAP kinase inhibitor (SB203580) significantly suppressed IL-8 synthesis in neutrophils. These results suggest that live
T. vaginalis
, particularly adherent trophozoites, can induce IL-8 production in neutrophils and that this action may be mediated through the NF-κB and MAP kinase signaling pathways. In other words,
T. vaginalis
-induced neutrophil recruitment may be mediated via the IL-8 expressed by neutrophils in response to activation by live
T. vaginalis
.
Identification of Novel Virulence-Associated Genes via Genome Analysis of Hypothetical Genes
Authors: Garbom Sara , Forsberg Åke , Wolf-Watz Hans , Kihlberg Britt-Marie 
Published: February 2004

ABSTRACT

The sequencing of bacterial genomes has opened new perspectives for identification of targets for treatment of infectious diseases. We have identified a set of novel virulence-associated genes (
vag
genes) by comparing the genome sequences of six human pathogens that are known to cause persistent or chronic infections in humans:
Yersinia pestis
,
Neisseria gonorrhoeae
,
Helicobacter pylori
,
Borrelia burgdorferi
,
Streptococcus pneumoniae
, and
Treponema pallidum.
This comparison was limited to genes annotated as hypothetical in the
T. pallidum
genome project. Seventeen genes with unknown functions were found to be conserved among these pathogens. Insertional inactivation of 14 of these genes generated nine mutants that were attenuated for virulence in a mouse infection model. Out of these nine genes, five were found to be specifically associated with virulence in mice as demonstrated by infection with
Yersinia pseudotuberculosis
in-frame deletion mutants. In addition, these five
vag
genes were essential only in vivo, since all the mutants were able to grow in vitro. These genes are broadly conserved among bacteria. Therefore, we propose that the corresponding
vag
gene products may constitute novel targets for antimicrobial therapy and that some
vag
mutants could serve as carrier strains for live vaccines.
Regulation of Adenosine Receptor Subtypes during Cultivation of Human Monocytes: Role of Receptors in Preventing Lipopolysaccharide-Triggered Respiratory Burst
Authors: Thiele Andrea , Kronstein Romy , Wetzel Anne , Gerth Anja , Nieber Karen , Hauschildt Sunna 
Published: February 2004

ABSTRACTAdenosine is a potent anti-inflammatory agent that modulates the function of cells involved in the inflammatory response. Here we show that it inhibits lipopolysaccharide (LPS)-induced formation of reactive oxygen intermediates (ROI) in both freshly isolated and cultured human monocytes. Blocking of adenosine uptake and inactivation of the adenosine-degrading enzyme adenosine deaminase enhanced the inhibitory action of adenosine, indicating that both pathways regulate the extracellular adenosine concentration. Adenosine-mediated inhibition could be reversed by XAC (xanthine amine congener), an antagonist of the adenosine receptor A2A, and MRS 1220 {N-9-chloro-2-(2-furanyl)[1, 2, 4]-triazolo[1,5-c]quinazolin-5-benzeneacetamide}, an A3receptor antagonist, in both cell populations, while DPCPX (1,3-dipropyl-8-cyclopentylxanthine), an A1receptor antagonist, had no effect. Similar to what was seen with adenosine, CGS 21680, an A2Aand A3receptor agonist, and IB-MECA, a nonselective A1and A3receptor agonist, dose dependently prevented ROI formation, indicating the involvement of A3and probably also A2Ain the suppressive effect of adenosine. Pretreatment of monocytes with adenosine did not lead to changes in the LPS-induced increase in intracellular calcium levels ([Ca2+]i). Thus, participation of [Ca2+]iin the action of adenosine seems unlikely. The adenosine-mediated suppression of ROI production was found to be more pronounced when monocytes were cultured for 18 h, a time point at which changes in the mRNA expression of adenosine receptors were observed. Most prominent was the increase in the A2Areceptor mRNA. These data demonstrate that cultivation of monocytes is accompanied by changes in the inhibitory action of adenosine mediated by A3and probably also the A2Areceptor and that regulation of adenosine receptors is an integral part of the monocyte differentiation program.