bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical Manifestations, Epidemiology, and Laboratory Diagnosis of Human Monocytotropic Ehrlichiosis in a Commercial Laboratory Setting
Authors: Olano Juan P. , Hogrefe Wayne , Seaton Brent , Walker David H. 
Published: September 2003

ABSTRACTClinical, epidemiological, and laboratory diagnostic issues of human monocytotropic ehrlichiosis (HME) were investigated in a retrospective case study conducted at a national reference laboratory (Focus Technologies, formerly MRL Reference Laboratory), and at the University of Texas Medical Branch at Galveston, Texas, during 1997 and 1998. Standard questionnaires were sent to physicians for each laboratory-diagnosed patient 2 days to 2 weeks after immunofluorescent antibody assay results were available. Among the 41 cases for which data were obtained, 32 (78%) were definite cases of HME, and 9 (22%) were probable cases of HME. Tick bite or exposure to ticks was recorded in more than 97% of cases. The most prominent clinical findings were fever, abdominal tenderness, and regional lymphadenopathy. There was an association between age and severity of illness. The main laboratory findings included leukopenia, thrombocytopenia, and elevated aspartate aminotransferase and alanine aminotransferase. Clinical and laboratory findings were nonspecific and were not good predictors of the severity of illness. The 90% of patients who received doxycycline treatment underwent rapid clinical improvement with a favorable outcome. The usual duration of effective treatment with doxycycline was 7 to 10 days. This retrospective study is unique because it was based in a commercial reference laboratory setting that receives specimens from different geographic locations. The clinical and laboratory information from 41 patients provides insight into the epidemiological, clinical, and laboratory characteristics of HME.
Detection by Two Enzyme-Linked Immunosorbent Assays of Antibodies toEhrlichia ruminantiumin Field Sera Collected from Sheep and Cattle in Ghana
Authors: Bell-Sakyi Lesley , Koney Enoch B. M. , Dogbey Otilia , Sumption Keith J. , Walker Alan R. , Bath Alasdair , Jongejan Frans 
Published: September 2003

ABSTRACTTwo serological tests for detection of antibodies toEhrlichia(previouslyCowdria)ruminantium, the causative agent of heartwater, were compared by using field sera collected from sheep and cattle as part of serosurveys in Ghana. Sera selected as either negative or positive by a new polyclonal competitive enzyme-linked immunosorbent assay (PC-ELISA) were tested by the indirect MAP1-B ELISA. Cutoff values of 14 percent positivity (14 PP) for both ruminant species were obtained for the MAP1-B ELISA by using preseroconversion Ghanaian sera and were compared with previously recommended cutoff values of 29 PP for sheep and 38 PP for cattle. With the 14-PP cutoff, of 151 sheep sera which tested negative by PC-ELISA, 89% were also negative by MAP1-B ELISA, while of 419 sheep sera positive by PC-ELISA, 98% were also positive by MAP1-B ELISA. Of 261 bovine sera negative by PC-ELISA, 82% were also negative by MAP1-B ELISA. Of 511 bovine sera positive by PC-ELISA, only 47% were positive by MAP1-B ELISA; these included 168 sera collected from cattle following first seroconversion as detected by both tests, with 125 of these sera positive by PC-ELISA but only 59 and 5 positive by MAP1-B ELISA with the 14- and 38-PP cutoff levels, respectively. These results indicate that both assays are highly sensitive and specific for detection ofE. ruminantiumexposure in sheep but that the MAP1-B ELISA lacks sensitivity for postseroconversion bovine sera in comparison to the PC-ELISA. Both tests confirmE. ruminantiumseroprevalence of at least 70% in Ghanaian sheep; levels of exposure amongAmblyomma variegatum-infested Ghanaian cattle are likely to be higher than the seroprevalence value of 66% obtained with the PC-ELISA.
Cloning and Expression of Mitochondrial Heat Shock Protein 70 ofTrypanosoma congolenseand Potential Use as a Diagnostic Antigen
Authors: Bannai Hiroshi , Sakurai Tatsuya , Inoue Noboru , Sugimoto Chihiro , Igarashi Ikuo 
Published: September 2003

ABSTRACTThe ability to use mitochondrial heat shock protein 70 (MTP) ofTrypanosoma congolenseas a diagnostic antigen was examined. One cDNA clone was obtained by immunoscreening of aT. congolenseprocyclic form (PCF) cDNA library with monoclonal antibody (MAb) 10F9. The cDNA clone contained an open reading frame of 1,977 bp encoding a polypeptide consisting of 659 amino acids. Southern blotting analysis indicated that there were at least three copies of theMTPgene in the haploid genome. Interference of the MTP RNA resulted in complete inhibition, which indicated that MTP is essential at the PCF stage. Northern and Western blotting analyses revealed that MTP is expressed both in the bloodstream form (BSF) and in PCF. The B-cell epitope recognized by MAb 10F9 was located within 206 amino acids from the C terminus. Depending on the conditions of protein extraction, MTP was cleaved into smaller polypeptides by endogenous proteases. However, the C-terminal epitope of MTP was preserved with a high degree of antigenicity, even after cleavage. Antibody detection by enzyme-linked immunosorbent assay with the truncated recombinant MTP revealed that anti-MTP antibodies exist in experimentally infected mouse sera. Thus, MTP may be useful as an antigen for the serodiagnosis of primaryT. congolenseinfection.
Detection of Antiendothelial Cell Antibodies by an Enzyme-Linked Immunosorbent Assay Using Antigens from Cell Lysate: Minimal Interference with Antinuclear Antibodies and Rheumatoid Factors
Authors: Drouet Christian , Nissou Marie-France , Ponard Denise , Arvieux Josiane , Dumestre-Pérard Chantal , Gaudin Philippe , Imbert Bernard , Massot Christian , Sarrot-Reynauld Françoise 
Published: September 2003

ABSTRACT

The objective of the present work was to set up a routine test adapted to screening for antiendothelial cell antibodies (AECAs) in serum samples with minimal interference from antinuclear antibodies (ANAs) or rheumatoid factors (RFs). We compared the titers of AECAs titrated following two enzyme-linked immunosorbent assays (ELISAs): (i) an ELISA with ethanol-fixed EA.hy926 monolayers as the antigenic substrate and (ii) an ELISA with nucleus-depleted lysates prepared from EA.hy926 cells and normalized for protein (1.0 to 1.7 mg/ml) and DNA (≤0.1 μg/ml) contents as a surrogate substrate (postnuclear supernatant ELISA [PNS-ELISA]). The AECA titers in 51 serum samples, including 28 samples containing ANAs, were compared. A significantly positive correlation (
r
= 0.77;
P
< 0.001) between the two series was shown only for the ANA-negative serum samples. Conversely, ANAs or RFs in samples were shown not to interfere in tests for AECAs by the PNS-ELISA. AECAs recognize their antigenic targets in postnuclear supernatants, which is representative of the endothelial antigenic content, with improvement of the reliability of the assay, a prerequisite to application of the assay for their evaluation in clinical practice.
Effects of Hypothermia on Mortality and Inflammatory Responses to Endotoxin-Induced Shock in Rats
Authors: Taniguchi Takumi , Kanakura Hiroko , Takemoto Yasuhiro , Yamamoto Ken 
Published: September 2003

ABSTRACTWe studied the effects of hypothermia on mortality rate, concentrations of tumor necrosis factor alpha and interleukin 6 in plasma, and the end products of nitric oxide (NO) in endotoxemia. It was found that moderate and mild hypothermia improved the mortality rate and attenuated cytokine responses and the elevation of the end products of NO after endotoxin injection and that these beneficial effects were similar for moderate and mild hypothermia.
Effects of Ovarian Steroids on Immunoglobulin-Secreting Cell Function in Healthy Women
Authors: Lü Fabien X. , Ma Zhongmin , Moser Susie , Evans Thomas G. , Miller Christopher J. 
Published: September 2003

ABSTRACTTo determine the effect of the ovarian hormone cycle on immunity, immunoglobulin-secreting cell (ISC) frequency and lymphocyte subsets were examined in the blood of healthy women. We found that immunoglobulin A (IgA)-secreting cells (IgA-ISC) were fourfold more frequent than IgG-ISC in peripheral blood mononuclear cells (PBMC). Further, the ISC frequency in PBMC was highest (P< 0.05) during the periovulatory stage of the menstrual cycle. Thus, endogenous ovarian steroids regulate the ISC frequency and this may explain why women are more resistant to viral infections and tend to have more immune-mediated diseases than men do.
Immunological Characterizations of a Cloned 13.1-Kilodalton Protein from Pathogenic
Naegleria fowleri
Authors: Cho Myoung-Soo , Jung Suk-Yul , Park Sun , Kim Kyongmin Hwang , Kim Hyung-Il , Sohn Seonghyang , Kim Han-Jip , Im Kyung-Il , Shin Ho-Joon 
Published: September 2003

ABSTRACT

We previously cloned an antigenic gene (named
nfa1
) from a cDNA library of
Naegleria fowleri
by immunoscreening. The
nfa1
gene had a coding nucleotide sequence consisting of 357 bases and produced a recombinant 13.1-kDa protein (Nfa1). In this study, to get more information regarding the recombinant Nfa1 protein (rNfa1), we produced an anti-Nfa1 polyclonal antibody from mice immunized with rNfa1 and used a peroxidase staining method to carry out immunocytochemistry experiments. In addition, we observed the effect of the presence of an anti-Nfa1 antibody on the in vitro cytotoxicity of
N. fowleri
against Chinese hamster ovary (CHO) cells. Trophozoites of
N. fowleri
in cultivation reacted strongly with a peroxidase-labeled anti-Nfa1 antibody. In inflammatory and necrotic regions of brain tissue infected with
N. fowleri
, labeled trophozoites that were stained brown were also observed. When examined using a transmission electron microscope, the Nfa1 protein showed pseudopodium-specific immunolocalization on a trophozoite of
N. fowleri
. When examined using a light microscope, CHO cells grown in cocultures with
N. fowleri
trophozoites (group I) for 48 h showed morphologically severe destruction but CHO cells grown in cocultures with
N. fowleri
trophozoites and an anti-Nfa1 polyclonal antibody (group II) showed less destruction. The results of a lactate dehydrogenase release assay showed that group I CHO cells exhibited 81% cytotoxicity and group II CHO cells exhibited 13.8% cytotoxicity.
Diagnostic Implications of Antigen-Induced Gamma Interferon, Nitric Oxide, and Tumor Necrosis Factor Alpha Production by Peripheral Blood Mononuclear Cells fromMycobacterium bovis-Infected Cattle
Authors: Waters W. R. , Palmer M. V. , Whipple D. L. , Carlson M. P. , Nonnecke B. J. 
Published: September 2003

ABSTRACTBovine tuberculosis in the United States has proven costly to cattle producers as well as to government regulatory agencies. While in vivo responsiveness to mycobacterial antigens is the current standard for the diagnosis of tuberculosis, in vitro assays are gaining acceptance, especially as ancillary or complementary tests. To evaluate in vitro indices of cellular sensitization, antigen-induced gamma interferon (IFN-γ), nitric oxide (NO), and tumor necrosis factor alpha (TNF-α) responses by blood mononuclear cells fromMycobacterium bovis-infected cattle were quantified and compared. Using an aerosol model of infection, two doses of each of two strains ofM. bovis(95-1315 and HC-2045T) were used to induce a range of IFN-γ, NO, and TNF-α responses. Infection-specific increases in NO, but not in IFN-γ or TNF-α, were detected in nonstimulated cultures at 48 h, a finding that is indicative of nonspecific activation and spontaneous release of NO. The infective dose ofM. bovisorganisms also influenced responses. At 34 days postinfection, IFN-γ, NO, and TNF-α responses in antigen-stimulated cells from cattle receiving 105CFU ofM. bovisorganisms were greater than responses of cells from cattle infected with 103CFU ofM. bovisorganisms.The NO response, but not the IFN-γ and TNF-α responses, was influenced by infective strains ofM. bovis. The TNF-α, NO, and IFN-γ responses followed similar kinetics, with strong positive associations among the three readouts. Overall, these findings indicate that NO and TNF-α, like IFN-γ, may prove useful as indices for the diagnosis of bovine tuberculosis.
Modified Direct Agglutination Test for Simplified Serologic Diagnosis of Leishmaniasis
Authors: Gómez-Ochoa P. , Castillo J. A. , Lucientes J. , Gascón M. , Zarate J. J. , Arbea J. I. , Larraga V. , Rodriguez C. 
Published: September 2003

ABSTRACT

Human leishmaniasis is a severe health problem in many countries around the world. Hence, a cheap, reliable, and accurate diagnostic test is required to fight this disease. Perhaps the direct agglutination test (DAT) meets these criteria, but antigen elaboration involves many difficulties. We have developed a new antigen elaboration method, the EasyDAT method, that avoids the problems associated with the DAT. In this study, we compared the traditional DAT antigen method with our EasyDAT antigen method by using canine sera. The sensitivities (100%) and specificities (98.7%) were the same for both methods; we therefore concluded that the EasyDAT
Leishmania
antigen method simplifies serologic diagnosis, making this method easier and cheaper to use.
Serotyping Isolates of
Anaplasma phagocytophilum
by Using Monoclonal Antibodies
Authors: Inokuma Hisashi , Brouqui Philippe , Dumler J. Stephen , Raoult Didier 
Published: September 2003

ABSTRACT

Ten mouse monoclonal antibodies (MAbs) that react with
Anaplasma phagocytophilum
(the human granulocytic ehrlichiosis agent) Webster isolates were developed. Seven different isolates of
A. phagocytophilum
were subtyped with these MAbs. Western blot analysis revealed that these MAbs reacted mainly with 41- to 46-kDa Msp2 proteins. Six MAbs reacted with all isolates. Four other MAbs reacted with human isolates from Wisconsin, but not with human isolates from New York or with animal isolates. Three different serotypes were identified. These features may lead to the development of other specific MAbs in order to provide tools for antigenic characterization of human isolates of
A. phagocytophilum
.
Differential Recognition of
Plasmodium falciparum
Merozoite Surface Protein 2 Variants by Antibodies from Malaria Patients in Brazil
Authors: Kanunfre Kelly A. , Leoratti Fabiana M. S. , Hoffmann Erika H. E. , Durlacher Rui R. , Ferreira Antônio W. , Moraes-Ávila Sandra L. , Ferreira Marcelo U. 
Published: September 2003

ABSTRACT

Four variants of merozoite surface protein 2 (MSP-2) of
Plasmodium falciparum
were used in serology to examine whether changes in repeat units affect its recognition by antibodies during infection with parasites of known MSP-2 types. The results indicate that variation in MSP-2 repeats may represent a mechanism for parasite immune evasion.
Ancient Origin of the Tryptophan Operon and the Dynamics of Evolutionary Change
Authors: Xie Gary , Keyhani Nemat O. , Bonner Carol A. , Jensen Roy A. 
Published: September 2003

SUMMARY

The seven conserved enzymatic domains required for tryptophan (Trp) biosynthesis are encoded in seven genetic regions that are organized differently (whole-pathway operons, multiple partial-pathway operons, and dispersed genes) in prokaryotes. A comparative bioinformatics evaluation of the conservation and organization of the genes of Trp biosynthesis in prokaryotic operons should serve as an excellent model for assessing the feasibility of predicting the evolutionary histories of genes and operons associated with other biochemical pathways. These comparisons should provide a better understanding of possible explanations for differences in operon organization in different organisms at a genomics level. These analyses may also permit identification of some of the prevailing forces that dictated specific gene rearrangements during the course of evolution. Operons concerned with Trp biosynthesis in prokaryotes have been in a dynamic state of flux. Analysis of closely related organisms among the Bacteria at various phylogenetic nodes reveals many examples of operon scission, gene dispersal, gene fusion, gene scrambling, and gene loss from which the direction of evolutionary events can be deduced. Two milestone evolutionary events have been mapped to the 16S rRNA tree of Bacteria, one splitting the operon in two, and the other rejoining it by gene fusion. The Archaea, though less resolved due to a lesser genome representation, appear to exhibit more gene scrambling than the Bacteria. The
trp
operon appears to have been an ancient innovation; it was already present in the common ancestor of Bacteria and Archaea. Although the operon has been subjected, even in recent times, to dynamic changes in gene rearrangement, the ancestral gene order can be deduced with confidence. The evolutionary history of the genes of the pathway is discernible in rough outline as a vertical line of descent, with events of lateral gene transfer or paralogy enriching the analysis as interesting features that can be distinguished. As additional genomes are thoroughly analyzed, an increasingly refined resolution of the sequential evolutionary steps is clearly possible. These comparisons suggest that present-day
trp
operons that possess finely tuned regulatory features are under strong positive selection and are able to resist the disruptive evolutionary events that may be experienced by simpler, poorly regulated operons.
Longevity Regulation inSaccharomyces cerevisiae: Linking Metabolism, Genome Stability, and Heterochromatin
Authors: Bitterman Kevin J. , Medvedik Oliver , Sinclair David A. 
Published: September 2003

SUMMARYWhen it was first proposed that the budding yeast Saccharomyces cerevisiae might serve as a model for human aging in 1959, the suggestion was met with considerable skepticism. Although yeast had proved a valuable model for understanding basic cellular processes in humans, it was difficult to accept that such a simple unicellular organism could provide information about human aging, one of the most complex of biological phenomena. While it is true that causes of aging are likely to be multifarious, there is a growing realization that all eukaryotes possess surprisingly conserved longevity pathways that govern the pace of aging. This realization has come, in part, from studies of S. cerevisiae, which has emerged as a highly informative and respected model for the study of life span regulation. Genomic instability has been identified as a major cause of aging, and over a dozen longevity genes have now been identified that suppress it. Here we present the key discoveries in the yeast-aging field, regarding both the replicative and chronological measures of life span in this organism. We discuss the implications of these findings not only for mammalian longevity but also for other key aspects of cell biology, including cell survival, the relationship between chromatin structure and genome stability, and the effect of internal and external environments on cellular defense pathways. We focus on the regulation of replicative life span, since recent findings have shed considerable light on the mechanisms controlling this process. We also present the specific methods used to study aging and longevity regulation in S. cerevisiae.
Candida albicansSecreted Aspartyl Proteinases in Virulence and Pathogenesis
Authors: Naglik Julian R. , Challacombe Stephen J. , Hube Bernhard 
Published: September 2003

SUMMARYCandida albicans is the most common fungal pathogen of humans and has developed an extensive repertoire of putative virulence mechanisms that allows successful colonization and infection of the host under suitable predisposing conditions. Extracellular proteolytic activity plays a central role in Candida pathogenicity and is produced by a family of 10 secreted aspartyl proteinases (Sap proteins). Although the consequences of proteinase secretion during human infections is not precisely known, in vitro, animal, and human studies have implicated the proteinases in C. albicans virulence in one of the following seven ways: (i) correlation between Sap production in vitro and Candida virulence, (ii) degradation of human proteins and structural analysis in determining Sap substrate specificity, (iii) association of Sap production with other virulence processes of C. albicans, (iv) Sap protein production and Sap immune responses in animal and human infections, (v) SAP gene expression during Candida infections, (vi) modulation of C. albicans virulence by aspartyl proteinase inhibitors, and (vii) the use of SAP-disrupted mutants to analyze C. albicans virulence. Sap proteins fulfill a number of specialized functions during the infective process, which include the simple role of digesting molecules for nutrient acquisition, digesting or distorting host cell membranes to facilitate adhesion and tissue invasion, and digesting cells and molecules of the host immune system to avoid or resist antimicrobial attack by the host. We have critically discussed the data relevant to each of these seven criteria, with specific emphasis on how this proteinase family could contribute to Candida virulence and pathogenesis.
Surviving the Acid Test: Responses of Gram-Positive Bacteria to Low pH
Authors: Cotter Paul D. , Hill Colin 
Published: September 2003

SUMMARYGram-positive bacteria possess a myriad of acid resistance systems that can help them to overcome the challenge posed by different acidic environments. In this review the most common mechanisms are described: i.e., the use of proton pumps, the protection or repair of macromolecules, cell membrane changes, production of alkali, induction of pathways by transcriptional regulators, alteration of metabolism, and the role of cell density and cell signaling. We also discuss the reponses ofListeria monocytogenes,Rhodococcus,Mycobacterium,Clostridium perfringens,Staphylococcus aureus,Bacillus cereus, oral streptococci, and lactic acid bacteria to acidic environments and outline ways in which this knowledge has been or may be used to either aid or prevent bacterial survival in low-pH environments.
Transmembrane Movement of Exogenous Long-Chain Fatty Acids: Proteins, Enzymes, and Vectorial Esterification
Authors: Black Paul N. , DiRusso Concetta C. 
Published: September 2003

SUMMARY
The processes that govern the regulated transport of long-chain fatty acids across the plasma membrane are quite distinct compared to counterparts involved in the transport of hydrophilic solutes such as sugars and amino acids. These differences stem from the unique physical and chemical properties of long-chain fatty acids. To date, several distinct classes of proteins have been shown to participate in the transport of exogenous long-chain fatty acids across the membrane. More recent work is consistent with the hypothesis that in addition to the role played by proteins in this process, there is a diffusional component which must also be considered. Central to the development of this hypothesis are the appropriate experimental systems, which can be manipulated using the tools of molecular genetics. Escherichia coli and Saccharomyces cerevisiae are ideally suited as model systems to study this process in that both (i) exhibit saturable long-chain fatty acid transport at low ligand concentrations, (ii) have specific membrane-bound and membrane-associated proteins that are components of the transport apparatus, and (iii) can be easily manipulated using the tools of molecular genetics. In both systems, central players in the process of fatty acid transport are fatty acid transport proteins (FadL or Fat1p) and fatty acyl coenzyme A (CoA) synthetase (FACS; fatty acid CoA ligase [AMP forming] [EC 6.2.1.3]). FACS appears to function in concert with FadL (bacteria) or Fat1p (yeast) in the conversion of the free fatty acid to CoA thioesters concomitant with transport, thereby rendering this process unidirectional. This process of trapping transported fatty acids represents one fundamental mechanism operational in the transport of exogenous fatty acids.