bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunoblot Assay Using Recombinant Antigens as a Supplemental Test To Confirm the Presence of Antibodies to
Trypanosoma cruzi
Authors: Cheng Kevin Y. , Chang Chi-Deu , Salbilla Vince A. , Kirchhoff Louis V. , Leiby David A. , Schochetman Gerald , Shah Dinesh O. 
Published: February 2007

ABSTRACT

The diagnosis of chronic Chagas' disease is generally made by detecting antibodies to
Trypanosoma cruzi
. Most conventional serological tests are based on lysates of whole parasites or semipurified antigen fractions from
T. cruzi
epimastigotes grown in culture. The occurrence of inconclusive and false-positive results has been a persistent problem with the conventional assays, and there is no universally accepted gold standard for confirmation of positive test results. We describe here an immunoblot assay for detecting antibodies to
T. cruzi
in which four chimeric recombinant antigens (rAgs), designated FP3, FP6, FP10, and TcF, are used as target antigens. Each of these rAgs is composed of several antigenically distinct regions and includes repetitive as well as nonrepetitive sequences. Each rAg is coated as a discrete line on a nitrocellulose strip. Assay sensitivity was assessed by testing 345 specimens known to be positive for antibodies to
T. cruzi
. All 345 of these samples showed two to four reactive test bands in addition to the three on-board control bands that are on each strip. Assay specificity was determined by testing 500 specimens from random U.S. blood donors, all of which gave negative results. Based on the results obtained in this study, we propose the following scheme for interpretation of test results: (i) no bands or a single test band = a negative result; (ii) two or more test bands with at least one band showing intensity of 1+ or higher = a positive result; and (iii) multiple faint test bands (±) = indeterminate result. Based on this scheme, the prototype immunoblot assay showed sensitivity of 100% (
n
= 345) and specificity of 100% (
n
= 500). Additionally, all 269 potentially cross-reacting and
T. cruzi
antibody-negative specimens tested negative in our immunoblot assay. The rAg-based immunoblot assay has potential as a supplemental test for confirming the presence of antibodies to
T. cruzi
in blood specimens and for identifying false-positive results obtained with other assays.
Zoonotic Vaccinia Virus Infection in Brazil: Clinical Description and Implications for Health Professionals
Authors: de Souza Trindade Giliane , Drumond Betania Paiva , Guedes Maria Isabel Maldonado Coelho , Leite Juliana Almeida , Mota Bruno Eduardo Fernandes , Campos Marco Antônio , da Fonseca Flávio Guimarães , Nogueira Maurício Lacerda , Lobato Zélia Inês Portela , Bonjardim Cláudio Antônio , Ferreira Paulo César Peregrino , Kroon Erna Geessien 
Published: February 2007

ABSTRACT
Bovine vaccinia virus outbreaks have been occurring in different regions of Brazil. We report here the time course of natural human infection by vaccinia virus and describe important clinical and epidemiological aspects of this zoonotic infection. The diagnosis of vaccinia virus infection was based on clinical, serological, and molecular procedures.
Molecular Identification of
Cryptococcus neoformans
Serotypes
Authors: Enache-Angoulvant A. , Chandenier J. , Symoens F. , Lacube P. , Bolognini J. , Douchet C. , Poirot J. L. , Hennequin C. 
Published: February 2007

ABSTRACT

Cryptococcus neoformans
is a fungal pathogen that causes life-threatening infections primarily in immunocompromised hosts. Based on the genetic characteristics and serologic properties of capsular polysaccharides, three varieties and five serotypes have been defined:
C. neoformans
var.
neoformans
(serotype D),
C. neoformans
var.
grubii
(serotype A), hybrid serotype AD, and
C. neoformans
var.
gattii
(serotypes B and C). Epidemiologic features, such as geographic distribution and ecologic niche, and clinical characteristics have been shown to be associated with serotypes. At the present time, serotyping is based on agglutination tests with either commercial or “homemade” antisera or on immunofluorescence assays using a monoclonal antibody directed against the capsule polysaccharide. In this paper, we describe two molecular methods (PCR-restriction enzyme analysis and length polymorphism analysis) for
C. neoformans
serotype identification. Both are based on the sequence characteristics of a fragment of the
CAP59
gene required for capsule biosynthesis. Testing of 72
C. neoformans
strains including representatives of the five serotypes demonstrated the reliability of these methods.
Detection of Extended-Spectrum Beta-Lactamases among
Enterobacteriaceae
by Use of Semiautomated Microbiology Systems and Manual Detection Procedures
Authors: Wiegand Irith , Geiss Heinrich K. , Mack Dietrich , Stürenburg Enno , Seifert Harald 
Published: February 2007

ABSTRACT

Three commercially available microbiology identification and susceptibility testing systems were compared with regard to their ability to detect extended-spectrum β-lactamase (ESBL) production in
Enterobacteriaceae
, i.e., the Phoenix Automated Microbiology System (BD Diagnostic Systems, Sparks, MD), the VITEK 2 System (bioMérieux, Marcy l'Etoile, France), and the MicroScan WalkAway-96 System (Dade Behring, Inc., West Sacramento, CA), using routine testing panels. One hundred fifty putative ESBL producers were distributed blindly to three participating laboratories. Conventional phenotypic confirmatory tests such as the disk approximation method, the CLSI double-disk synergy test, and the Etest ESBL were also evaluated. Biochemical and molecular characterization of β-lactamases performed at an independent laboratory was used as the reference method. One hundred forty-seven isolates of
Escherichia coli
,
Klebsiella pneumoniae
,
Klebsiella oxytoca
,
Enterobacter cloacae
,
Enterobacter aerogenes
,
Citrobacter freundii
,
Serratia marcescens
,
Proteus mirabilis
,
Proteus vulgaris
, and
Morganella morganii
were investigated. Of these isolates, 85 were identified as ESBL producers by the reference method. The remaining isolates were identified as non-ESBL producers; they were either hyperproducers of their chromosomal AmpC, Koxy, or SHV enzymes or lacked any detectable β-lactamase activity. The system with the highest sensitivity for the detection of ESBLs was the Phoenix (99%), followed by the VITEK 2 (86%) and the MicroScan (84%); however, specificity was more variable, ranging from 52% (Phoenix) to 78% (VITEK 2). The performance of the semiautomated systems differed widely with the species investigated. The sensitivities of the conventional test methods ranged from 93 to 94%. The double-disk synergy test showed the highest specificity and positive predictive value among all test methods, i.e., 97% and 98%, respectively.
Controlled Evaluation of the IDI-MRSA Assay for Detection of Colonization by Methicillin-Resistant
Staphylococcus aureus
in Diverse Mucocutaneous Specimens
Authors: de San Nour , Denis Olivier , Gasasira Marie-Fabrice , De Mendonça Ricardo , Nonhoff Claire , Struelens Marc J. 
Published: February 2007

ABSTRACT

Rapid and reliable detection of methicillin-resistant
Staphylococcus aureus
(MRSA) carriers is crucial for the effective control of MRSA transmission in healthcare facilities. The aim of this study was to verify the performance of the IDI-MRSA real-time PCR assay for direct MRSA detection in diverse mucocutaneous swabs from hospitalized patients. Swabs from nares (
n
= 522) and skin or other superficial sites (
n
= 478) were prospectively collected for MRSA screening from 466 patients admitted to an 858-bed teaching hospital. Swabs were inoculated onto selective chromogenic MRSA-ID agar, buffer extraction solution for IDI-MRSA assay, and enrichment broth. MRSA was detected by culture in 100 specimens from 47 patients. Compared to enrichment culture, the sensitivity and specificity of the PCR assay were 81.0 and 97.0%, respectively, and its positive and negative predictive values were 75.0 and 97.9%, respectively. The IDI-MRSA assay was more sensitive on swabs from nares (90.6%) than from other body sites (76.5%,
P
< 0.01). The PCR assay detected MRSA in 42 of 47 patients with culture positive study samples. Of 26 patients with culture-negative but PCR-positive study samples, 11 were probable true MRSA carriers based on patient history and/or positive culture on a new sample. The median turnaround time for PCR results was 19 h versus 3 days for agar culture results and 6 days for enrichment culture results. These data confirm the value of IDI-MRSA assay for rapid screening of MRSA mucocutaneous carriage among hospitalized patients. Cost-effectiveness studies are warranted to evaluate the impact of this assay on infection control procedures in healthcare settings.
High Frequencies of Clindamycin and Tetracycline Resistance in Methicillin-Resistant
Staphylococcus aureus
Pulsed-Field Type USA300 Isolates Collected at a Boston Ambulatory Health Center
Authors: Han Linda L. , McDougal Linda K. , Gorwitz Rachel J. , Mayer Kenneth H. , Patel Jean B. , Sennott Janet M. , Fontana John L. 
Published: February 2007

ABSTRACT

Individual or multiple resistance to clindamycin, tetracycline, erythromycin, levofloxacin, or mupirocin was detected in a large proportion of methicillin-resistant
Staphylococcus aureus
pulsed-field type USA300 isolates collected at an ambulatory health center in Boston. The clindamycin, tetracycline, and mupirocin resistance genes identified in these isolates are commonly associated with plasmids.
Deletion of
fetA
Gene Sequences in Serogroup B and C
Neisseria meningitidis
Isolates
Authors: Marsh Jane W. , O'Leary Mary M. , Shutt Kathleen A. , Harrison Lee H. 
Published: February 2007

ABSTRACT

The immunogenic iron-regulated FetA outer membrane protein of
Neisseria meningitidis
is one of various outer membrane proteins that have been considered potential meningococcal vaccine candidates. In this report, we describe the characterization of three meningococcal isolates that have deleted
fetA
sequences through genetic recombination at repetitive elements.
Real-Time PCR Assay Using Specimens on Filter Disks as a Template for Detection of Cytomegalovirus in Urine
Authors: Nozawa Naoki , Koyano Shin , Yamamoto Yumiko , Inami Yuhki , Kurane Ichiro , Inoue Naoki 
Published: February 2007

ABSTRACT
Since congenital cytomegalovirus (CMV) infection causes late-onset sequelae, the identification of CMV-infected newborns is important. For this purpose, we established a simple real-time PCR assay using a filter disk. Combined with the collection of urine using filter papers placed in the diaper, this assay can make CMV screening more feasible and cost-effective.
Characterization of Class I Newcastle Disease Virus Isolates from Hong Kong Live Bird Markets and Detection Using Real-Time Reverse Transcription-PCR
Authors: Kim L. Mia , King Daniel J. , Suarez David L. , Wong Chun W. , Afonso Claudio L. 
Published: February 2007

ABSTRACT
Newcastle disease viruses isolated from Hong Kong live bird markets (LBMs) were not detected by a USDA-validated matrix gene real-time reverse transcription-PCR (RT-PCR) assay. Based upon phylogenetic analysis of the fusion gene, these viruses were related to lentogenic class I viruses found in U.S. LBMs and wild waterfowl. An alternative real-time RT-PCR assay which complements the matrix gene assay was developed to efficiently detect class I viruses.
Identification of a Third Human Polyomavirus
Authors: Allander Tobias , Andreasson Kalle , Gupta Shawon , Bjerkner Annelie , Bogdanovic Gordana , Persson Mats A. A. , Dalianis Tina , Ramqvist Torbjörn , Andersson Björn 
Published: February 2007

ABSTRACT
We have previously reported on a system for large-scale molecular virus screening of clinical samples. As part of an effort to systematically search for unrecognized human pathogens, the technology was applied for virus screening of human respiratory tract samples. This resulted in the identification of a previously unknown polyomavirus provisionally named KI polyomavirus. The virus is phylogenetically related to other primate polyomaviruses in the early region of the genome but has very little homology (<30% amino acid identity) to known polyomaviruses in the late region. The virus was found by PCR in 6 (1%) of 637 nasopharyngeal aspirates and in 1 (0.5%) of 192 fecal samples but was not detected in sets of urine and blood samples. Since polyomaviruses have oncogenic potential and may produce severe disease in immunosuppressed individuals, continued searching for the virus in different medical contexts is important. This finding further illustrates how unbiased screening of respiratory tract samples can be used for the discovery of diverse virus types.
Human Immunodeficiency Virus Type 1: Resistance to Nucleoside Analogues and Replicative Capacity in Primary Human Macrophages
Authors: Perez-Bercoff Danielle , Wurtzer Sébastien , Compain Séverine , Benech Henri , Clavel François 
Published: February 2007

ABSTRACTAntiretroviral treatment failure is associated with the emergence of resistant human immunodeficiency virus type 1 (HIV-1) populations which often express altered replicative capacity (RC). The resistance and RC of clinical HIV-1 strains, however, are generally assayed using activated peripheral blood mononuclear cells (PBMC) or tumor cell lines. Because of their high proliferation rate and concurrent high deoxynucleoside triphosphate (dNTP) content, both resistance and RC alterations might be misestimated in these cell systems. We have evaluated the resistance of HIV-1 clones expressing a variety of RT resistance mutations in primary human macrophages using a single cycle system. Our experiments indicate that d4T, ddI, and 3TC are more potent in macrophages than in HeLa-derived P4 tumor cells. Mutant viruses bearing thymidine analogue mutations (TAMs) or the K65R mutation had similar resistance levels in the two cell types. Strikingly, however, the M184V mutant, although fully resistant to 3TC in P4 cells, maintained some susceptibility to 3TC in macrophages from 8 of 11 donors. Using the same system, we found that the impact of resistance mutations on HIV RC was minimal in activated PBMC and in P4 cells. In contrast, mutant viruses exhibited strongly impaired RC relative to the wild type (WT) in macrophages, with the following RC order: WT > two TAMs > four TAMs = M184V > K65R. In undifferentiated monocytes, WT virus replication could be detected in three of six donors, but replication of all mutant viruses remained undetectable. Altogether, our results confirm that nucleoside reverse transcriptase inhibitors (NRTIs) are powerful antiviral agents in differentiated macrophages, reveal that HIV resistance to some NRTIs may be less efficient in these cells, and indicate that resistance-associated loss of RC is more pronounced in macrophages than in high-dNTP content cell systems.
Fusogenic Variants of a Noncytopathic Paramyxovirus
Authors: Seth Shaguna , Skountzou Ioanna , Gernert Kim M. , Compans Richard W. 
Published: February 2007

ABSTRACTSER virus is a type 5 parainfluenza virus that does not exhibit syncytium formation, in contrast to most other paramyxoviruses. This property has been attributed, at least in part, to the presence of an extension of the cytoplasmic tail (CT) of the SER F protein, as truncations or mutations of this region resulted in enhanced fusion. In this study we used repeated passage to select for mutant SER viruses, which were found to be fusogenic. The mutant viruses replicated at levels comparable to or higher than the wild-type SER virus and caused plaque formation, in contrast to the wild-type virus which does not form plaques. The mutants differed strikingly in their plaque sizes. The F genes of mutant viruses were cloned and sequenced and shared some mutations, including a proline-to-leucine change at position 22 and an isoleucine-to-leucine substitution at position 191; other changes that were specific to each mutant were also found. The HN proteins of mutant viruses also showed mutations spanning the length of the protein whereas the M protein showed a consistent mutation, threonine to isoleucine, at position 129. The structure of the F protein was used to identify residues involved in the mutant phenotypes in terms of their location and proximity to heptad repeat domains.
Kaposi's Sarcoma-Associated Herpesvirus Promotes Angiogenesis by Inducing Angiopoietin-2 Expression via AP-1 and Ets1
Authors: Ye Feng-Chun , Blackbourn David J. , Mengel Michael , Xie Jian-Ping , Qian Li-Wu , Greene Whitney , Yeh I-Tien , Graham David , Gao Shou-Jiang 
Published: February 2007

ABSTRACT
Infection by Kaposi's sarcoma-associated herpesvirus (KSHV) is required for the development of Kaposi's sarcoma (KS), a highly inflammatory angiogenic tumor of endothelial cells commonly found in untreated AIDS patients. Angiopoietin 2 (Ang-2) modulates the vasculature during inflammation and angiogenesis, but the mechanism by which KSHV regulates Ang-2 expression has not been investigated. Here, we show that KSHV infection of primary human umbilical vein endothelial cells induced the expression and release of Ang-2, which in turn was required for KSHV-induced paracrine-dependent angiogenesis in vivo. Ang-2 was strongly expressed in small vessels and spindle tumor cells in KS tumors. Mechanistically, KSHV activated the Ang-2 promoter via AP-1 and Ets1 transcriptional factors, which were mediated by ERK, JNK, and p38 mitogen-activated protein kinase (MAPK) pathways. Our findings demonstrate the importance of Ang-2 in KS angiogenesis and define a novel role for AP-1 and MAPK pathways in regulating angiogenesis. This study also illustrates a distinct mechanism by which a tumor virus modulates vasculature to promote tumorigenesis and exemplifies the convergence of oncogenesis and angiogenesis pathways in tumor development.
Kaposi's Sarcoma-Associated Herpesvirus Induces Sustained NF-κB Activation during De Novo Infection of Primary Human Dermal Microvascular Endothelial Cells That Is Essential for Viral Gene Expression
Authors: Sadagopan Sathish , Sharma-Walia Neelam , Veettil Mohanan Valiya , Raghu Hari , Sivakumar Ramu , Bottero Virginie , Chandran Bala 
Published: February 2007

ABSTRACT
In vitro Kaposi's sarcoma-associated herpesvirus (KSHV) infection of primary human dermal microvascular endothelial (HMVEC-d) cells and human foreskin fibroblast (HFF) cells is characterized by the induction of preexisting host signal cascades, sustained expression of latency-associated genes, transient expression of a limited number of lytic genes, and induction of several cytokines, growth factors, and angiogenic factors. Since NF-κB is a key molecule involved in the regulation of several of these factors, here, we examined NF-κB induction during de novo infection of HMVEC-d and HFF cells. Activation of NF-κB was observed as early as 5 to 15 min postinfection by KSHV, and translocation of p65-NF-κB into nuclei was detected by immunofluorescence assay, electrophoretic mobility shift assay, and p65 enzyme-linked immunosorbent assay. IκB phosphorylation inhibitor (Bay11-7082) reduced this activation significantly. A sustained moderate level of NF-κB induction was seen during the observed 72 h of in vitro KSHV latency. In contrast, high levels of ERK1/2 activation at earlier time points and a moderate level of activation at later times were observed. p38 mitogen-activated protein kinase was activated only at later time points, and AKT was activated in a cyclic manner. Studies with UV-inactivated KSHV suggested a role for virus entry stages in NF-κB induction and a requirement for KSHV viral gene expression in sustained induction. Inhibition of NF-κB did not affect target cell entry by KSHV but significantly reduced the expression of viral latent open reading frame 73 and lytic genes. KSHV infection induced the activation of several host transcription factors, including AP-1 family members, as well as several cytokines, growth factors, and angiogenic factors, which were significantly affected by NF-κB inhibition. These results suggest that during de novo infection, KSHV induces sustained levels of NF-κB to regulate viral and host cell genes and thus possibly regulates the establishment of latent infection.
Transmission and Adaptation of Chronic Wasting Disease to Hamsters and Transgenic Mice: Evidence for Strains
Authors: Raymond Gregory J. , Raymond Lynne D. , Meade-White Kimberly D. , Hughson Andrew G. , Favara Cynthia , Gardner Donald , Williams Elizabeth S. , Miller Michael W. , Race Richard E. , Caughey Byron 
Published: February 2007

ABSTRACT
In vitro screening using the cell-free prion protein conversion system indicated that certain rodents may be susceptible to chronic wasting disease (CWD). Therefore, CWD isolates from mule deer, white-tailed deer, and elk were inoculated intracerebrally into various rodent species to assess the rodents' susceptibility and to develop new rodent models of CWD. The species inoculated were Syrian golden, Djungarian, Chinese, Siberian, and Armenian hamsters, transgenic mice expressing the Syrian golden hamster prion protein, and RML Swiss and C57BL10 wild-type mice. The transgenic mice and the Syrian golden, Chinese, Siberian, and Armenian hamsters had limited susceptibility to certain of the CWD inocula, as evidenced by incomplete attack rates and long incubation periods. For serial passages of CWD isolates in Syrian golden hamsters, incubation periods rapidly stabilized, with isolates having either short (85 to 89 days) or long (408 to 544 days) mean incubation periods and distinct neuropathological patterns. In contrast, wild-type mouse strains and Djungarian hamsters were not susceptible to CWD. These results show that CWD can be transmitted and adapted to some species of rodents and suggest that the cervid-derived CWD inocula may have contained or diverged into at least two distinct transmissible spongiform encephalopathy strains.
Inhibition of Airway Na
+
Transport by Respiratory Syncytial Virus
Authors: Kunzelmann Karl , Sun Jane , Meanger Jayesh , King Nicholas J. , Cook David I. 
Published: February 2007

ABSTRACT

In previous studies, we have shown that two major respiratory pathogens, influenza virus and parainfluenza virus, produce acute alterations in ion transport upon contacting the apical membrane of the respiratory epithelium. In the present study, we examine the effects on ion transport by the mouse tracheal epithelium of a third major respiratory pathogen, respiratory syncytial virus (RSV). RSV infections are associated with fluid accumulation in the respiratory tract and cause illnesses that range in severity from rhinitis, sinusitis, otitis media, and bronchitis to bronchiolitis and pneumonia. We find that within minutes of RSV contacting the apical membrane; it inhibits amiloride-sensitive Na
+
transport by the epithelium. This effect is mediated by protein kinase C and is reproduced by recombinant viral F (fusion) protein. Since this inhibition is not accompanied by any alteration in the epithelial responses to carbachol or to forskolin plus 3-isobutyl-1-methylxanthine (IBMX), it is not due to a nonspecific toxic action of the virus. The inhibition also appears to require Toll-like receptor 4 and the presence of asialogangliosides in the apical membrane. Since the concentration range over which this inhibition is observed (10
2
to 10
5
PFU/ml) is comparable to the viral concentrations observed in clinical and experimental RSV infections, it seems likely that direct inhibition by the virus of epithelial Na
+
transport may contribute to the fluid accumulation that is observed in RSV infections.