bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Epidemiology of Outbreak of Respiratory Syncytial Virus within Bone Marrow Transplantation Unit
Authors: Taylor Graham S. , Vipond I. Barry , Caul E. Owen 
Published: July 2002

ABSTRACT
During the winter of 1995–1996, eight of nine bone marrow transplantation (BMT) unit patients were infected with the same strain of respiratory syncytial virus (RSV). This RSV strain was not detected in 20 hospitalized patients from the community, suggesting that the BMT unit infections did not occur by independent incidents of transmission from the community.
Detection of
Chlamydia trachomatis
and
Neisseria gonorrhoeae
by Enzyme Immunoassay, Culture, and Three Nucleic Acid Amplification Tests
Authors: Van Dyck E. , Ieven M. , Pattyn S. , Van Damme L. , Laga M. 
Published: July 2002

ABSTRACT

The purpose of this study was to evaluate and compare three commercially available nucleic acid amplification tests (NAATs) for the detection of
Neisseria gonorrhoeae
and
Chlamydia trachomatis
. Roche PCR and Becton Dickinson strand displacement amplification (SDA) were performed on 733 endocervical swab specimens from commercial sex workers. Abbott ligase chain reaction (LCR) was performed on a subset of 396 samples. Endocervical specimens from all women were also tested by culture for
N. gonorrhoeae
and by Syva MicroTrak enzyme immunoassay (EIA) for
C. trachomatis
. A positive
N. gonorrhoeae
result was defined as a positive result by culture or by two NAATs, and a positive
C. trachomatis
result was defined as a positive result by two tests. According to these definitions, the sensitivities and specificities for the subsample of 396 specimens of
N. gonorrhoeae
culture, PCR, SDA, and LCR were 69.8, 95.2, 88.9, and 88.9% and 100, 99.4, 100, and 99.1%, respectively; the sensitivities and specificities of
C. trachomatis
EIA, PCR, SDA, and LCR were 42.0, 98.0, 94.0, and 90.0% and 100, 98.0, 100, and 98.6%, respectively. The performance characteristics of
N. gonorrhoeae
culture, PCR, and SDA and
C. trachomatis
EIA, PCR, and SDA for all 733 specimens were defined without inclusion of LCR results and by discrepant analysis after resolution of discordant
N. gonorrhoeae
PCR results and of discordant
C. trachomatis
EIA and PCR results by LCR testing. The sensitivities of
N. gonorrhoeae
culture, PCR, and SDA before and after LCR resolution were 67.8, 95.7, and 93.9% and 65, 95.8, and 90.0%, respectively. The sensitivities of
C. trachomatis
EIA, PCR, and SDA decreased from 39.4, 100, and 100% to 38.7, 98.7, and 94.7%, respectively. All three NAATs proved to be superior to
N. gonorrhoeae
culture and to
C. trachomatis
EIA. The accuracies of the different NAATs were quite similar. SDA was the only amplification assay with 100% specificity for detection of both
N. gonorrhoeae
and
C. trachomatis
in endocervical specimens.
The Common Ovine Shiga Toxin 2-Containing
Escherichia coli
Serotypes and Human Isolates of the Same Serotypes Possess a Stx2d Toxin Type
Authors: Ramachandran Vidiya , Hornitzky Michael A. , Bettelheim Karl A. , Walker Mark J. , Djordjevic Steven P. 
Published: July 2002

ABSTRACT

Shiga toxin 2 (Stx2) has been reported as the main Shiga toxin associated with human disease. In addition, the Stx2 toxin type can have a profound impact on the degree of tissue damage in animal models. We have characterized the
stx
2
subtype of 168 Shiga toxin-producing
Escherichia coli
(STEC) isolates of which 146 were derived from ovine sources (principally feces and meat) and 22 were isolated from humans. The ovine STEC isolates were of serotypes that have been shown to occur commonly in the gastrointestinal tract of healthy sheep. The major
stx
2
subtype in the ovine isolates was shown to be
stx
2d-Ount
(119 of 146 [81.5%]) and was predominantly associated with serotypes O75:H
−
/H8/H40, O91:H
−
, O123:H
−
, O128:H2, and OR:H2. However, 17 of 18 (94.4%) ovine isolates of serotype O5:H
−
possessed a
stx
2d-O111/OX3a
subtype. Furthermore, STEC isolates of serotypes commonly found in sheep and recovered from both clinical and nonclinical human infections also contained a
stx
2d
(
stx
2d-Ount/O111/OX3a
) subtype. These studies suggest that a specific
stx
2
subtype(s) associates with serotype and may have important epidemiological implications for tracing sources of
E. coli
during outbreaks of STEC-associated diseases in humans.
Spread of Drug-Resistant Pulmonary Tuberculosis in Estonia
Authors: Krüüner Annika , Hoffner Sven E. , Sillastu Heinart , Danilovits Manfred , Levina Klavdia , Svenson Stefan B. , Ghebremichael Solomon , Koivula Tuija , Källenius Gunilla 
Published: July 2002

ABSTRACT

Restriction fragment length polymorphism (RFLP) analysis of 209
Mycobacterium tuberculosis
clinical isolates obtained from newly detected pulmonary tuberculosis patients (151 male and 58 female; mean age, 41 years) in Estonia during 1994 showed that 61 isolates (29%) belonged to a genetically closely related group of isolates, family A, with a predominant IS
6110
banding pattern. These strains shared the majority of their IS
6110
DNA-containing restriction fragments, representing a predominant banding pattern (similarity, >65%). This family A comprised 12 clusters of identical isolates, and the largest cluster comprised 10 strains. The majority (87.5%) of all multidrug-resistant (MDR) isolates, 67.2% of all isolates with any drug resistance, but only 12% of the fully susceptible isolates of
M. tuberculosis
belonged to family A. These strains were confirmed by spoligotyping as members of the Beijing genotype family. The spread of Beijing genotype MDR
M. tuberculosis
strains was also frequently seen in 1997 to 1999. The members of this homogenous group of drug-resistant
M. tuberculosis
strains have contributed substantially to the continual emergence of drug-resistant tuberculosis all over Estonia.
Genotypes and Clinical Phenotypes of Hepatitis B Virus in Patients with Chronic Hepatitis B Virus Infection
Authors: Kao Jia-Horng , Chen Pei-Jer , Lai Ming-Yang , Chen Ding-Shinn 
Published: July 2002

ABSTRACT

Genotype C of hepatitis B virus (HBV) has been shown to be associated with a poor clinical outcome, compared to genotype B. To explore the clinical phenotypes, with special reference to the seroconversion of hepatitis B e antigen (HBeAg) and frequency of acute exacerbation between patients infected with HBV genotypes B and C, a cohort of 272 Taiwanese patients with chronic HBV infection was analyzed. According to the status of HBeAg at enrollment and frequency of acute exacerbation during the follow-up period, five groups of patients with distinct clinical phenotypes were categorized. Of the 272 HBV carriers, 185 (68%) were infected with HBV genotype B and the remaining 87 (32%) were infected with genotype C. Among them, 150 (55%) were positive for HBeAg and patients with genotype C infection tended to have a higher positive rate of HBeAg than those with genotype B infection (63 versus 51%). Genotype B was more prevalent than genotype C in different groups of HBV carriers. However, the prevalence of genotype C in patients with multiple episodes of acute exacerbation who failed to have HBeAg seroconversion was significantly higher than in all 272 patients (50 versus 32%,
P
= 0.025), in those with HBeAg seroconversion after only one episode of acute exacerbation (50 versus 12%,
P
= 0.01), or in those negative for HBeAg at enrollment and without acute exacerbations (50 versus 23%,
P
= 0.002). In conclusion, patients with genotype C infection have a more aggressive clinical phenotype than do those with genotype B infection, which contributes to the former group's progressive liver disease and poor clinical outcomes.
Molecular Analysis of Group A
Streptococcus
Type
emm18
Isolates Temporally Associated with Acute Rheumatic Fever Outbreaks in Salt Lake City, Utah
Authors: Smoot James C. , Korgenski E. Kent , Daly Judy A. , Veasy L. George , Musser James M. 
Published: July 2002

ABSTRACT

Acute rheumatic fever (ARF) and subsequent rheumatic heart disease are rare but serious sequelae of group A
Streptococcus
(GAS) infections in most western countries. Salt Lake City (SLC), Utah, and the surrounding intermountain region experienced a resurgence of ARF in 1985 which has persisted. The largest numbers of cases were encountered in 1985-1986 and in 1997-1998. Organisms with a mucoid colony phenotype when grown on blood agar plates were temporally associated with the higher incidence of ARF. To develop an understanding of the molecular population genetic structure of GAS strains associated with ARF in the SLC region, 964 mucoid and nonmucoid pharyngeal isolates recovered in SLC from 1984 to 1999 were studied by sequencing the
emm
gene. Isolates with an
emm18
allele were further characterized by sequencing the
spa
,
covR
, and
covS
genes. Peak periods of ARF were associated with GAS isolates possessing an
emm18
allele encoding the protein found in serotype M18 isolates. Among the serotype M18 isolates, the difference in the number of C repeats produced three size variants. Variation was limited in
spa
, a gene that encodes a streptococcal protective antigen, and
covR
and
covS
, genes that encode a two-component regulatory system that, when inactivated, results in a mucoid phenotype and enhanced virulence in mouse infection models. Pulsed-field gel electrophoresis showed a single restriction profile for serotype M18 organisms isolated during both peak periods of ARF. In SLC, the incidence of ARF coresurged with the occurrence of GAS serotype M18 isolates that have very restricted genetic variation.
Detection of Porcine Circovirus Types 1 and 2 in Serum and Tissue Samples of Pigs with and without Postweaning Multisystemic Wasting Syndrome
Authors: Calsamiglia Maria , Segalés Joaquim , Quintana Josefina , Rosell Carles , Domingo Mariano 
Published: July 2002

ABSTRACT
Presence of porcine circovirus type 1 (PCV1) and PCV2 was studied in sera and superficial inguinal lymph nodes from postweaning multisystemic wasting syndrome (PMWS)-affected and non-PMWS-affected pigs by using in situ hybridization and PCR. PCV1 and PCV2 were found in less than 3% and more than 50% of the samples, respectively. The most sensitive technique and site was PCR in superficial inguinal lymph nodes, but in situ hybridization correlated better with presence of characteristic lesions.
Antimicrobial Susceptibility Testing of
Bacillus anthracis
: Comparison of Results Obtained by Using the National Committee for Clinical Laboratory Standards Broth Microdilution Reference and Etest Agar Gradient Diffusion Methods
Authors: Mohammed M. Jasmine , Marston Chung K. , Popovic Tanja , Weyant Robbin S. , Tenover Fred C. 
Published: July 2002

ABSTRACT

We determined the patterns of antimicrobial susceptibility of 65 isolates of
Bacillus anthracis
(50 historical and 15 recent U.S. clinical isolates) to nine antimicrobial agents using the National Committee for Clinical Laboratory Standards (NCCLS) broth microdilution reference method. The results for the 50 historical
B. anthracis
isolates obtained by the broth microdilution method were compared to those generated by the Etest agar gradient diffusion method. One isolate of
B. anthracis
was β-lactamase positive and resistant to penicillin (MIC, 128 μg/ml); a second isolate, which was β-lactamase negative, was borderline penicillin resistant, with the penicillin MICs for the isolate varying from 0.12 to 0.25 μg/ml; and the remainder of the isolates were β-lactamase negative and penicillin susceptible (MICs, ≤0.12 μg/ml). Approximately 78% of the isolates showed reduced susceptibility to ceftriaxone (MICs, ≥16 μg/ml). All
B. anthracis
isolates were susceptible to chloramphenicol (MICs, ≤8 μg/ml), ciprofloxacin (MICs, ≤ 1 μg/ml), clindamycin (MICs, ≤0.5 μg/ml), rifampin (MICs, ≤0.5 μg/ml), tetracycline (MICs, ≤0.06 μg/ml), and vancomycin (MICs, ≤2 μg/ml) by use of NCCLS breakpoints for staphylococci. All 15 recent
B. anthracis
isolates from the United States were susceptible to penicillin, doxycycline, and ciprofloxacin. By use of the susceptibility breakpoint for staphylococci of ≤0.5 μg/ml, 97% of the
B. anthracis
isolates tested would have been categorized as intermediate to erythromycin. No statistically significant difference was found between the results of broth microdilution testing and the results of the Etest method for any of the antimicrobial agents tested; however, the results for penicillin obtained by the Etest were 1 to 9 dilutions lower than those obtained by the broth microdilution method. The differences in the penicillin MICs by the Etest method and the difficulties of reading the Etest results through the glass of a biological safety cabinet may limit the utility of this alternate susceptibility testing method for
B. anthracis
isolates.
High-Sensitivity PCR Detection of Parvovirus B19 in Plasma
Authors: Daly P. , Corcoran A. , Mahon B. P. , Doyle S. 
Published: July 2002

ABSTRACT

Parvovirus B19 (B19) is a human pathogen transmitted to susceptible individuals via respiratory secretions and contaminated blood or blood products. B19 levels in pooled plasma of less than 10
4
genome equivalents/ml may not be infectious, while those greater than 10
7
/ml are capable of transmitting infection. A World Health Organization (WHO) B19 DNA international standard has been recently introduced. The purpose of the present work was to develop a PCR-enzyme-linked immunosorbent assay (PCR-ELISA) calibrated against the WHO B19 DNA international standard which could easily and reliably detect B19 DNA levels in plasma above 10
4
IU/ml (6.5 × 10
3
genome equivalents/ml). A B19 PCR-ELISA system was developed which uses a dinitrophenylated oligonucleotide probe to detect immobilized biotinylated amplicons following single-round PCR amplification. The level of B19 DNA (in international units per milliliter) in individual and pooled plasma specimens was evaluated. Proteinase K treatment of plasma was found to be sufficient to quantitatively release B19 DNA. The B19 PCR-ELISA had a sensitivity of detection of 1.6 × 10
3
IU/ml B19 DNA and a dynamic range extending from 8 to 1,000 IU of B19 DNA (equivalent to 1.6 × 10
3
to 2 × 10
5
IU of B19 DNA/ml). Furthermore, the antibody profile of pooled plasma products was determined in terms of B19 immunoglobulin G (IgG) (in international units per milliliter). The B19 IgG level was found to be 64.7 ± 17.5 IU/ml (mean ± standard deviation). The B19 PCR-ELISA, which is calibrated against the B19 DNA international standard, may have an application for the rapid screening of plasma minipools for B19 DNA, thereby leading to an improvement in blood product safety.
Enterococcus gallinarum
Endocarditis Occurring on Native Heart Valves
Authors: Dargere Sylvie , Vergnaud Michel , Verdon Renaud , Saloux Eric , Le Page Olivier , Leclercq Roland , Bazin Claude 
Published: July 2002

ABSTRACT

We report the first case of
Enterococcus gallinarum
endocarditis developing on normal native heart valves. Using phenotypic and molecular methods, a precise identification of this naturally vancomycin-resistant species allowed an optimal antibiotic therapy and the patient's recovery.
Differential Narrow Focusing of Immunodominant Human Immunodeficiency Virus Gag-Specific Cytotoxic T-Lymphocyte Responses in Infected African and Caucasoid Adults and Children
Authors: Goulder Philip J. R. , Brander C. , Annamalai K. , Mngqundaniso N. , Govender U. , Tang Y. , He S. , Hartman K. E. , O'Callaghan C. A. , Ogg G. S. , Altfeld M. A. , Rosenberg E. S. , Cao H. , Kalams S. A. , Hammond M. , Bunce M. , Pelton S. I. , Burchett S. A. , McIntosh K. , Coovadia H. M. , Walker B. D. 
Published: July 2002

ABSTRACTCytotoxic T-lymphocyte (CTL) activity plays a central role in control of viral replication and in determining outcome in cases of human immunodeficiency virus type 1 (HIV-1) infection. Incorporation of important CTL epitope sequences into candidate vaccines is, therefore, vital. Most CTL studies have focused upon small numbers of adult Caucasoid subjects infected with clade-B virus, whereas the global epidemic is most severe in sub-Saharan African populations and predominantly involves clade-C infection in both adults and children. In this study, sensitive enzyme-linked immunospot (elispot) assays have been utilized to identify the dominant Gag-specific CTL epitopes targeted by adults and children infected with clade-B or -C virus. Cohorts evaluated included 44 B-clade-infected Caucasoid American and African American adults and children and 37 C-clade-infected African adults and children from Durban, South Africa. The results show that 3 out of 46 peptides spanning p17Gagand p24Gagsequences tested contain two-thirds of the dominant Gag-specific epitopes, irrespective of the clade, ethnicity, or age group studied. However, there were distinctive differences between the dominant responses made by Caucasoids and Africans. Dominant responses in Caucasoids were more often within p17Gagpeptide residues 16 to 30 (38 versus 12%;P< 0.01), while p24Gagpeptide residues 41 to 60 contained the dominant Gag epitope more often in the African subjects tested (39 versus 4%;P< 0.005). Within this 20-mer p24Gag, an epitope presented by both B42 and B81 is defined which represents the dominant Gag response in >30% of the total infected population in Durban. This epitope is closely homologous with dominant HIV-2 and simian immunodeficiency virus Gag-specific CTL epitopes. The fine focusing of dominant CTL responses to these few regions of high immunogenicity is of significance to vaccine design.
Kinetic Analysis of Human Immunodeficiency Virus Type 1 Assembly Reveals the Presence of Sequential Intermediates
Authors: Tritel Marc , Resh Marilyn D. 
Published: July 2002

ABSTRACT
The assembly and budding of lentiviruses, such as human immunodeficiency virus type 1 (HIV-1), are mediated by the Gag protein precursor, but the molecular details of these processes remain poorly defined. In this study, we have combined pulse-chase techniques with density gradient centrifugation to identify, isolate, and characterize sequential kinetic intermediates in the lentivirus assembly process. We show that newly synthesized HIV-1 Gag rapidly forms cytoplasmic protein complexes that are resistant to detergent treatment, sensitive to protease digestion, and degraded intracellularly. A subpopulation of newly synthesized Gag binds membranes within 5 to 10 min and over several hours assembles into membrane-bound complexes of increasing size and/or density that can be resolved on Optiprep density gradients. These complexes likely represent assembly intermediates because they are not observed with assembly-defective Gag mutants and can be chased into extracellular viruslike particles. At steady state, nearly all of the Gag is present as membrane-bound complexes in various stages of assembly. The identification of sequential assembly intermediates provides the first demonstration that HIV-1 particle assembly proceeds via an ordered process. Assembly intermediates should serve as attractive targets for the design of antiviral agents that interfere with the process of particle production.
A Cytoplasmic RNA Vector Derived from Nontransmissible Sendai Virus with Efficient Gene Transfer and Expression
Authors: Li Hai-Ou , Zhu Ya-Feng , Asakawa Makoto , Kuma Hidekazu , Hirata Takahiro , Ueda Yasuji , Lee Yun-Sik , Fukumura Masayuki , Iida Akihiro , Kato Atsushi , Nagai Yoshiyuki , Hasegawa Mamoru 
Published: July 2002

ABSTRACT

We have recovered a virion from defective cDNA of
Sendai virus
(SeV) that is capable of self-replication but incapable of transmissible-virion production. This virion delivers and expresses foreign genes in infected cells, and this is the first report of a gene expression vector derived from a defective viral genome of the
Paramyxoviridae
. First, functional ribonucleoprotein complexes (RNPs) were recovered from SeV cloned cDNA defective in the F (envelope fusion protein) gene, in the presence of plasmids expressing nucleocapsid protein and viral RNA polymerase. Then the RNPs were transfected to the cells inducibly expressing F protein. Virion-like particles thus obtained had a titer of 0.5 × 10
8
to 1.0 × 10
8
cell infectious units/ml and contained F-defective RNA genome. This defective vector amplified specifically in an F-expressing packaging cell line in a trypsin-dependent manner but did not spread to F-nonexpressing cells. This vector infected and expressed an enhanced green fluorescent protein reporter gene in various types of animal and human cells, including nondividing cells, with high efficiency. These results suggest that this vector has great potential for use in human gene therapy and vaccine delivery systems.
Assembly of Retrovirus Capsid-Nucleocapsid Proteins in the Presence of Membranes or RNA
Authors: Zuber Guy , McDermott Jason , Karanjia Sonya , Zhao Weiyi , Schmid Michael F. , Barklis Eric 
Published: July 2002

ABSTRACT
Retrovirus Gag precursor (PrGag) proteins direct the assembly of roughly spherical immature virus particles, while after proteolytic processing events, the Gag capsid (CA) and nucleocapsid (NC) domains condense on viral RNAs to form mature retrovirus core structures. To investigate the process of retroviral morphogenesis, we examined the properties of histidine-tagged (His-tagged) Moloney murine leukemia (M-MuLV) capsid plus nucleocapsid (CANC) (His-MoCANC) proteins in vitro. The His-MoCANC proteins bound RNA, possessed nucleic acid-annealing activities, and assembled into strand, circle (or sphere), and tube forms in the presence of RNA. Image analysis of electron micrographs revealed that tubes were formed by cage-like lattices of CANC proteins surrounding at least two different types of protein-free cage holes. By virtue of a His tag association with nickel-chelating lipids, His-MoCANC proteins also assembled into planar sheets on lipid monolayers, mimicking the membrane-associated immature PrGag protein forms. Membrane-bound His-MoCANC proteins organized into two-dimensional (2D) cage-like lattices that were closely related to the tube forms, and in the presence of both nickel-chelating lipids and RNAs, 2D lattice forms appeared similar to lattices assembled in the absence of RNA. Our observations are consistent with a M-MuLV morphogenesis model in which proteolytic processing of membrane-bound Gag proteins permits CA and NC domains to rearrange from an immature spherical structure to a condensed mature form while maintaining local protein-protein contacts.
Infectious Hematopoietic Necrosis Virus Matrix Protein Inhibits Host-Directed Gene Expression and Induces Morphological Changes of Apoptosis in Cell Cultures
Authors: Chiou Pinwen P. , Kim Carol H. , Ormonde Patricia , Leong Jo-Ann C. 
Published: July 2002

ABSTRACT
Infectious hematopoietic necrosis virus (IHNV) infection in tissue culture cells has previously been shown to result in the shutdown of host protein synthesis, cell rounding, and cell death. We report here an investigation of the cytopathogenicity of the viral phosphoprotein (P or M1), matrix (M or M2), and nonvirion (NV) proteins in cultured fish cells. The expression of M alone potently inhibited reporter gene expression from a viral and an interferon (IFN)-inducible promoter, whereas P and NV did not produce a similar effect. Northern blot analysis further revealed a reduction in the steady-state level of reporter mRNA when the M gene was cotransfected into cells; conversely, M mRNA was not drastically reduced in the same cells. By immunofluorescence confocal microscopy, fragmented nuclei were found in some cells expressing M protein but not in cells expressing P, NV, or β-galactosidase protein. Electron microscopy revealed the morphological changes associated with apoptosis in the M-transfected cells. Furthermore, IHNV infection was shown to produce DNA “laddering” in cultured cells. Taken together, these data suggested at least two functions for M protein in an IHNV infection: down regulation of host transcription and the induction of programmed cell death. In the course of these experiments, we also discovered that NV expression was associated with cell rounding, the first biological effect on cells to be attributed to the NV gene.