bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antifreeze Solution Improves DNA Recovery by Preserving the Integrity of Pathogen-Infected Blood and Other Tissues
Authors: Leal-Klevezas Diana Sara , Martı́nez-Vázquez Irma Olivia , Cuevas-Hernández Baltazar , Martı́nez-Soriano Juan Pablo 
Published: July 2002

ABSTRACT
Preserving blood samples for shipping and later DNA extraction has been performed by cooling, freezing, drying, freeze-drying, and protease treatment, among other methods. Most methods to preserve field samples for further DNA extraction do not prevent cellular and DNA damage or are useful only in preserving them for short periods. This report introduces a novel method for blood and tissue that allows preservation in freezing temperatures for a prolonged period of time. The solution reported here (20% ethylene glycol-propylene glycol) preserves cells and tissues integrity, as judged by microscopic analysis, and improves DNA yield and quality.
A Point Mutation in a Domain of Gamma Interferon Receptor 1 Provokes Severe Immunodeficiency
Authors: Allende Luis M. , López-Goyanes Alberto , Paz-Artal Estela , Corell Alfredo , Garcı́a-Pérez M. Angel , Varela Pilar , Scarpellini Atilio , Negreira Sagrario , Palenque Elia , Arnaiz-Villena Antonio 
Published: July 2002

ABSTRACTGamma interferon (IFN-γ) and the cellular responses induced by it are essential for controlling mycobacterial infections. Most patients bearing an IFN-γ receptor ligand-binding chain (IFN-γR1) deficiency present gross mutations that truncate the protein and prevent its expression, giving rise to severe mycobacterial infections and, frequently, a fatal outcome. In this report a new mutation that affects the IFN-γR1 ligand-binding domain in a Spanish patient with mycobacterial disseminated infection and multifocal osteomyelitis is characterized. The mutation generates an amino acid change that does not abrogate protein expression on the cellular surface but that severely impairs responses after the binding of IFN-γ (CD64 and HLA class II induction and tumor necrosis factor alpha and interleukin-12 production). A patient's younger brother, who was also probably homozygous for the mutation, died from meningitis due toMycobacterium bovis. These findings suggest that a point mutation may be fatal when it affects functionally important domains of the receptor and that the severity is not directly related to a lack of IFN-γ receptor expression. Future research on these nontruncating mutations will make it possible to develop new therapeutical alternatives in this group of patients.
Internal Transcribed Spacer Regions of rRNA Genes of
Pneumocystis carinii
from Monkeys
Authors: Hsueh John Y. C. , Bohm Rudolf P. , Didier Peter J. , Tang Xing , Lasbury Mark E. , Li Baozheng , Jin Shaoling , Bartlett Marilyn S. , Smith James W. , Lee Chao-Hung 
Published: July 2002

ABSTRACT

Analysis of sequence variations among isolates of
Pneumocystis carinii
f. sp.
macacae
from 14 Indian rhesus monkeys (
Macaca mulatta
) at the internal transcribed spacer (ITS) regions of the nuclear rRNA gene was undertaken. Like those from
P. carinii
f. sp.
hominis
, the ITS sequences from various
P. carinii
f. sp.
macacae
isolates were not identical. Two major types of sequences were found. One type of sequence was shared by 13 isolates. These 13 sequences were homologous but not identical. Variations were found at 13 of the 180 positions in the ITS1 region and 28 of the 221 positions in the ITS2 region. These sequence variations were not random but exhibited definite patterns when the sequences were aligned. According to this sequence variation, ITS1 sequences were classified into three types and ITS2 sequences were classified into five types. The remaining specimen had ITS1 and ITS2 sequences substantially different from the others. Although some specimens had the same ITS1 or ITS2 sequence, all 14 samples exhibited a unique whole ITS sequence (ITS1 plus ITS2). The 5.8S rRNA gene sequences were also analyzed, and only two types of sequences that differ by only one base were found. Unlike
P. carinii
f. sp.
hominis
infections in humans, none of the monkey lung specimens examined in this study were found to be infected by more than one type of
P. carinii
f. sp.
macacae
. These results offer insights into the genetic differences between
P. carinii
organisms which infect distinct species.
Neutralizing Antibodies against Autologous Human Immunodeficiency Virus Type 1 Isolates in Patients with Increasing CD4 Cell Counts despite Incomplete Virus Suppression during Antiretroviral Treatment
Authors: Sarmati Loredana , d'Ettorre Gabriella , Nicastri Emanuele , Ercoli Lucia , Uccella Ilaria , Massetti Paola , Parisi Saverio Giuseppe , Vullo Vincenzo , Andreoni Massimo 
Published: July 2002

ABSTRACT

Antiretroviral-treated human immunodeficiency virus (HIV) type 1-seropositive individuals can remain clinically stable for a long period of time with an increasing CD4 cell count irrespective of incomplete viral suppression. We evaluated the role of neutralizing antibody (NtAb) activity in the etiopathogenesis of this viro-immunological disconnection (defined as an increasing CD4
+
-cell count despite a persistent, detectable viral load during antiretroviral therapy) in 33 patients failing therapy with two analogue nucleoside reverse transcriptase inhibitors. An HIV NtAb titer of ≥1:25 was detected in specimens from 16 out of 33 (48%) patients. A significant correlation was found between NtAb titers and CD4
+
-cell counts (
P
= 0.001;
r
= 0.546) but not with HIV RNA levels in plasma. Five patients with a viro-immunological disconnection had an NtAb titer of >1:125, statistically higher than the NtAb titers for the remaining 28 patients with both virologic and immunologic failure (
P
< 0.0001). The HIV-specific humoral immune response could play a role during antiretroviral treatment to improve immunological function despite an incomplete suppression of viral load.
Spinal Cord Involvement in Uncomplicated Herpes Zoster
Authors: Steiner Israel , Steiner-Birmanns Bettina , Levin Netta , Hershko Klila , Korn-Lubetzki Isabelle , Biran Iftah 
Published: July 2002

ABSTRACT
We prospectively evaluated herpes zoster patients during the acute phase of the disease for central nervous system involvement. Of 24 patients with spinal zoster, 13 (54%) had spinal cord abnormality, which was asymptomatic in 12 of the 13. Age but not lack of acyclovir treatment was associated with such involvement. In all but 2, neurological involvement resolved within 6 months. Although the mechanism responsible for the neurological abnormalities is unknown, findings may support the hypothesis that zoster is associated with spread of viral infection into the spinal cord and therefore support the possibility that zoster is due to active viral replication in the ganglion.
Biological Activity of a Mouse-Human Chimeric Immunoglobulin G2 Antibody toCryptococcus neoformansPolysaccharide
Authors: Westin Kwon Katherine , Lendvai Nikoletta , Morrison Sherie , Trinh K. Ryan , Casadevall Arturo 
Published: July 2002

ABSTRACTThe variable regions of the heavy and light chains of the protective murine monoclonal antibody (MAb) 2H1 (m2H1) were expressed with the human constant region genes for immunoglobulin G2 (IgG2) and kappa, respectively, to construct a chimeric antibody (ch2H1). ch2H1 retains the specificity of the parent MAb, exhibits biological activity, and lacks the toxicity of the parent murine IgG1 in chronically infected mice.
Preconception Seroconversion and Maternal Seronegativity at Delivery Do Not Rule Out the Risk of Congenital Toxoplasmosis
Authors: Chemla C. , Villena I. , Aubert D. , Hornoy P. , Dupouy D. , Leroux B. , Bory J. P. , Pinon J. M. 
Published: July 2002

ABSTRACT
We describe two unusual cases of congenital toxoplasmosis, one occurring after preconception maternal infection with cervical adenopathies and the other occurring after maternal infection at the very end of pregnancy with maternal seronegativity at delivery. These documented cases of congenital toxoplasmosis demonstrate the value of extending the serologic monitoring period during pregnancy, according to the individual clinical context.
Interaction of Fimbriae of
Haemophilus influenzae
Type B with Heparin-Binding Extracellular Matrix Proteins
Authors: Virkola Ritva , Brummer Mirko , Rauvala Heikki , van Alphen Loek , Korhonen Timo K. 
Published: July 2002

ABSTRACT

The interaction of the fimbriae of
Haemophilus influenzae
type b (Hib) with two heparin-binding extracellular matrix proteins, human fibronectin (Fn) and heparin-binding growth-associated molecule (HB-GAM) from mouse, were studied. The fimbriated Hib strain 770235 fim+, as well as the recombinant strain
E. coli
HB101(pMH140), which expressed Hib fimbriae, adhered strongly to Fn and HB-GAM immobilized on glass. Purified Hib fimbriae bound to Fn and HB-GAM, and within the Fn molecule, the binding was localized to the N-terminal 30,000-molecular-weight (30K) and 40K fragments, which contain heparin-binding domains I and II, respectively. Fimbrial binding to Fn, HB-GAM, and the 30K and the 40K fragments was inhibited by high concentrations of heparin. The results show that fimbriae of Hib interact with heparin-binding extracellular matrix proteins. The nonfimbriated Hib strain 770235 fim− exhibited a low level of adherence to Fn but did not react with HB-GAM, indicating that Hib strains also possess a fimbria-independent mechanism to interact with Fn.
Protective Antigen-Mediated Antibody Response against a Heterologous Protein Produced In Vivo byBacillus anthracis
Authors: Brossier Fabien , Weber-Levy Martine , Mock Michèle , Sirard Jean-Claude 
Published: July 2002

ABSTRACTBacillus anthracissecretes a lethal toxin composed of two proteins, the lethal factor (LF) and the protective antigen (PA), which interact within the host or in vitro at the surfaces of eukaryotic cells. Immunization with attenuatedB. anthracisstrains induces an antibody response against PA and LF. The LF-specific response is potentiated by the binding of LF to PA. In this study, we investigated the capacity of PA to increase the antibody response against a foreign antigen. We constructed a chimeric gene encoding the PA-binding part of LF (LF254) fused to the C fragment of tetanus toxin (ToxC). The construct was introduced by allelic exchange into the locus encoding LF. Two recombinantB. anthracisstrains secreting the hybrid protein LF254-ToxC were generated, one in a PA-producing background and the other in a PA-deficient background. Mice were immunized with spores of the strains, and the humoral response and protection against tetanus toxin were assessed. TheB. anthracisstrain producing both PA and LF254-ToxC induced significantly higher antibody titers and provided better protection against a lethal challenge with tetanus toxin than did its PA-deficient counterpart. Thus, PA is able to potentiate protective immunity against a heterologous antigen, demonstrating the potential ofB. anthracisrecombinant strains for use as live vaccine vehicles.
Stable Expression of a New Chimeric Fluorescent Reporter in the Human Malaria Parasite
Plasmodium falciparum
Authors: Kadekoppala Madhusudan , Kline Kimberly , Akompong Thomas , Haldar Kasturi 
Published: July 2002

ABSTRACT

Stable transfection of a new, chimeric reporter in the human malaria parasite
Plasmodium falciparum
confers green fluorescence and methotrexate resistance that can be quantitated by Western blotting and flow cytometry. This provides a sensitive, live reporter for exploitation of genomic and high-throughput assays for the identification of new pathogenic determinants.
Capsular Polysaccharide and O-Specific Antigen Divergently Modulate Pulmonary Neutrophil Influx in an
Escherichia coli
Model of Gram-Negative Pneumonitis in Rats
Authors: Russo Thomas A. , Davidson Bruce A. , Priore Roger L. , Carlino Ulrike B. , Helinski Jadwiga D. , Knight Paul R 
Published: July 2002

ABSTRACT

Enteric gram-negative bacilli cause a severe, often life-threatening pneumonia. An improved understanding of the pathogenesis of this infection may lead to improved treatment. Nearly all of the responsible gram-negative bacilli possess capsular polysaccharides and/or an O-specific antigen as part of their lipopolysaccharide (LPS). We hypothesized that these surface polysaccharides may modulate the pulmonary host response. To investigate this, a rat pneumonitis model was used, and pulmonary neutrophil influx, a critical aspect of host defense, was measured. To assess for the effect of the capsule and O-specific antigen on this host response, three proven, isogenic derivatives that are deficient in capsular polysaccharide alone (CP9.137), the O-specific antigen moiety of the LPS alone (CP921), and both the capsular polysaccharide and O-specific antigen (CP923), as well as their wild-type parent (CP9), were used as challenge strains at various intratracheal challenge inocula (CI). Total lung myeloperoxidase (MPO), a surrogate marker for neutrophils, was measured for 15 h post-bacterial challenge. To determine the effect of capsule and the O-specific antigen on the measured MPO levels, a mathematical model was developed and used to describe the MPO levels as a function of time for each CI of each of the four strains. The results from this analysis demonstrated that in the absence of the K54 capsule, 80.7 times the CI is necessary to achieve the same maximum MPO level relative to K54 positive strains (
P
< 0.0001). In contrast, a diametric effect was observed in the absence of the O-specific antigen, where 0.13 times the CI was necessary to achieve the same maximum MPO level relative to O4-positive strains (
P
= 0.0032). No interactive effect was observed between the capsule and the O-specific antigen. These findings demonstrate that these surface polysaccharides modulate pulmonary neutrophil influx and suggest that the K54 capsular polysaccharide is a proinflammatory mediator and that the O4-specific antigen attenuates the proinflammatory response. If these speculations are substantiated, an understanding of how the capsule and the O-specific antigen modulate host response could have significant therapeutic implications. The potential use of biologic modulators directed against the host response, as well as approaches based on inactivating bacterial components (e.g., surface polysaccharides) in attempts to modify sepsis syndromes, could be developed.
A Commercial Preparation of Catalase Inhibits Nitric Oxide Production by Activated Murine Macrophages: Role of Arginase
Authors: Tian Y. , Xing Y. , Magliozzo R. , Yu K. , Bloom B. R. , Chan J. 
Published: July 2002

ABSTRACT

Catalase is widely used as a pharmacological probe to evaluate the role of hydrogen peroxide in antimicrobial activities of phagocytic cells. This report demonstrates that the ability of a commercial preparation of catalase to inhibit concomitantly macrophage antimycobacterial activity and production of reactive nitrogen intermediates can be attributed, at least in part, to the depletion of
l
-arginine by contaminating arginase. In experimental systems that employ pharmacological probes, the existence of nonspecific effects should be considered in data interpretation.
Evidence That Hyaluronidase Is Not Involved in Tissue Invasion of the Protozoan Parasite
Entamoeba histolytica
Authors: Nickel Rosa , Stern Robert , Leippe Matthias 
Published: July 2002

ABSTRACT

As previous reports suggested that a hyaluronidase is involved in tissue invasion of
Entamoeba histolytica
, we searched for such an activity in trophozoite extracts. A hyaluronidase activity was not detectable in long-term cultures or in amoebae freshly passaged through a gerbil liver, as evidenced by four different techniques.
Replacement of Histidine 340 with Alanine Inactivates the Group A
Streptococcus
Extracellular Cysteine Protease Virulence Factor
Authors: Gubba Siddeswar , Cipriano Vincent , Musser James M. 
Published: July 2002

ABSTRACT

Streptococcus pyogenes
expresses a highly conserved extracellular cysteine protease that is a virulence factor for invasive disease, including soft tissue infection. Site-directed mutagenesis was used to generate a His340Ala recombinant mutant protein that was made as a stable 40-kDa zymogen by
Escherichia coli
. Purified His340Ala protein was proteolytically inactive when bovine casein and human fibronectin were used as substrates. Wild-type 28-kDa streptococcal protease purified from
S. pyogenes
processed the 40-kDa mutant zymogen to a 28-kDa mature form, a result suggesting that the derivative protein retained structural integrity. The data are consistent with the hypothesis that His340 is an enzyme active site residue, an idea confirmed by recent solution of the zymogen crystal structure (T. F. Kagawa, J. C. Cooney, H. M. Baker, S. McSweeney, M. Liu, S. Gubba, J. M. Musser, and E. N. Baker, Proc. Natl. Acad. Sci. USA 97:2235–2240, 2000). The data provide additional insight into structure-function relationships in this
S. pyogenes
virulence factor.
Lipoarabinomannans Activate the Protein Tyrosine Kinase Hck in Human Neutrophils
Authors: Astarie-Dequeker Catherine , Nigou Jérôme , Puzo Germain , Maridonneau-Parini Isabelle 
Published: July 2002

ABSTRACTThe mycobacterial lipoarabinomannans (LAMs) are glycosylphosphatidyl-myo-inositol-anchored lipoglycans with diverse biological activities. It has been shown that purified LAMs interact directly, or indirectly, through receptors with the plasma membrane receptors of target cells located in domains rich in glycosylphosphatidylinositol-anchored proteins that contain Src family protein tyrosine kinases. To examine whether LAMs could activate Src-related kinases, human neutrophils were exposed to mannosylated LAMs (ManLAMs) purified from the vaccinal strainMycobacterium bovisBCG and to phosphoinositol-capped LAMs (AraLAM or PILAM) obtained from the nonpathogenic speciesMycobacterium smegmatis. We report first that both ManLAMs and PILAMs activate Hck in a rapid and transient manner and second that complete deacylation of ManLAM abolished its effect on Hck activity, thereby demonstrating that acylation of LAM but not mannosylation is critical for Hck activation. These data indicate that Hck is involved in the signaling pathway of LAMs, molecules known for their ability to trigger several responses in eukaryotic cells.
Extract ofNippostrongylus brasiliensisStimulates Polyclonal Type-2 Immunoglobulin Response by Inducing De Novo Class Switch
Authors: Ehigiator Humphrey N. , Stadnyk Andrew W. , Lee Timothy D. G. 
Published: July 2002

ABSTRACTInfection with the nematode parasiteNippostrongylus brasiliensisinduces a pronounced type-2 T-cell response that is associated with marked polyclonal immunoglobulin E (IgE) and IgG1 production in mice. To examine the differential roles of the infection and products produced by nematodes, we investigated a soluble extract ofN. brasiliensisfor the ability to mediate this type-2 response. We found that the extract induced a marked increase in IgE and IgG1 levels, similar to that induced by the infection. The extract did not affect the level of IgG2a in serum, showing that the effect was specific to IgE and IgG1 (type-2-associated immunoglobulin) rather than inducing a nonspecific increase in all immunoglobulin isotypes. This response was also associated with increased interleukin-4 production in vitro. These results confirm that the extract, like infection, is a strong inducer of polyclonal type-2 responses and a reliable model for investigating the regulation of nematode-induced responses. The extract induced the production of IgG1 when added to in vitro cultures of lipopolysaccharide-stimulated B cells. This provides evidence for the induction of class switch. It did not induce upregulation of IgG1 in naive (unstimulated) B cells or expand B cells in in vitro cultures. Analysis of DNA from the spleens of mice treated with the extract by digestion-circularization PCR demonstrated a marked increase in the occurrence of γ1 switch region gene recombination in the cells in vivo. These results provide strong evidence that soluble worm products are able to mediate the marked polyclonal γ1/ɛ response and that infection is not required to mediate this response. Furthermore, these data provide evidence that the soluble nematode extract induces this effect by causing de novo class switch of B cells and not by an expansion of IgG1 B cells or an increase in antibody production by IgG1 plasma cells.
Molecular Cloning, Sequencing, Expression, and Characterization of an Immunogenic 43-Kilodalton Lipoprotein of
Bartonella bacilliformis
That Has Homology to NlpD/LppB
Authors: Padmalayam Indira , Kelly Timothy , Baumstark Barbara , Massung Robert 
Published: July 2002

ABSTRACT

A recombinant clone expressing an immunoreactive antigen of
Bartonella bacilliformis
was isolated by screening a genomic DNA library with serum from a patient with the chronic verruga phase of bartonellosis. The clone, pBIPIM-17, contained a partial open reading frame that expressed an immunoreactive fusion protein. Subsequent rescreening of the library by plaque hybridization resulted in the isolation of recombinant clones that contain the entire open reading frame. The open reading frame (ORF-401) is capable of encoding a protein of 401 amino acids with a predicted molecular mass of 43 kDa. The deduced amino acid sequence of the encoded protein was found to be highly homologous to a recently identified bacterial lipoprotein (LppB/NlpD) which has been associated with virulence. Evidence has been provided to show that the 43-kDa antigen of
B. bacilliformis
is a lipoprotein and that it is likely to use the same biosynthetic pathway as other bacterial lipoproteins. This is the first report to date that characterizes a lipoprotein of
B. bacilliformis
. The immunogenicity of the
B. bacilliformis
LppB homologue was demonstrated by Western blot analysis using sera from patients with clinical bartonellosis. Sera from patients who had a high titer for
Bartonella henselae
, the causative agent of bacillary angiomatosis and cat scratch disease, also recognized the recombinant 43-kDa antigen, suggesting that a homologue of this antigen is present in
B. henselae
. Using a cocktail of synthetic peptides corresponding to predicted major antigenic sites, polyclonal antiserum specific for the LppB homologue of
B. bacilliformis
was generated. This antiserum did not recognize the NlpD homologue of
Escherichia coli
or the 43-kDa antigen of
B. henselae
.
T-Cell Responses to Immunodominant LACK Antigen Do Not Play a Critical Role in Determining Susceptibility of BALB/c Mice toLeishmania mexicana
Authors: Torrentera Fabiola Aguilar , Glaichenhaus Nicolas , Laman Jon D. , Carlier Yves 
Published: July 2002

ABSTRACTAlthough BALB/c mice develop lesions when infected withLeishmania mexicana, the mechanisms which are responsible for susceptibility to this parasite have not been elucidated. In contrast, susceptibility of BALB/c mice toLeishmania majorhas been shown to depend on the early production of interleukin-4 (IL-4) by T cells which react to the parasitic LACK antigen. Here, we demonstrate that the lesions induced byL. mexicanaare delayed compared to those induced byL. majorbut rapidly develop at later time points. Interestingly, while LACK-tolerant BALB/c-derived IE-LACK transgenic mice were resistant toL. major, they were susceptible toL. mexicanaand developed lesions similar to those observed in wild-type BALB/c mice. The latter result was observed despite the fact that (i) LACK was expressed byL. mexicana, (ii) splenocytes from BALB/c mice were able to stimulate LACK-specific T-cell hybridoma cells when incubated with liveL. mexicanapromastigotes, and (iii) LACK-specific T cells contributed to IL-4 production inL. mexicana-infected BALB/c mice. Thus, in contrast to what was observed forL. major-infected mice, LACK-specific T cells do not play a critical role in determining susceptibility toL. mexicana. Although BALB/c mice are susceptible to bothL. majorandL. mexicana, the mechanisms which are responsible for susceptibility to these parasites are likely to be different.