bluuebunny/crossref_metadata_2025_split huggingface dataset:
Efficacy of a Swab Transport System in Maintaining Viability of
Neisseria gonorrhoeae
and
Streptococcus pneumoniae
Authors: Farhat Shaker E. , Thibault Mary , Devlin Roslyn 
Published: July 2002

ABSTRACT

The efficacy of swab transport systems in maintaining viability of
Neisseria gonorrhoeae
and
Streptococcus pneumoniae
is crucial both for establishing definitive diagnosis and for monitoring emerging resistance. We tested the efficacy of a newly modified Amies charcoal swab transport system, the StarSwab SP131X (Starplex Scientific, Inc., Etobicoke, Ontario, Canada), by using a combined total of 31 clinical and American Type Culture Collection stock reference strains of
N. gonorrhoeae
and
S. pneumoniae
in 46 suspensions of concentrations ranging from 10
5
to 10
8
CFU/ml. Triplicate swabs per strain held at room temperature for 0, 24, and 48 h were plated without prior vortexing, and their growths were graded. All 31 strains were viable at 0 and 24 h. Gonococcal viability at 48 h varied considerably, even among strains with comparable inoculum sizes, suggesting that viability might be strain dependent and confirming the different structural and growth profiles of gonococcal strains.
S. pneumoniae
strains showed consistent viability, with all strains recovered at all holding periods. This study demonstrates that the StarSwab SP131X is capable of maintaining the viability of
N. gonorrhoeae
and
S. pneumoniae
for at least 24 and 48 h, respectively, and reinforces the need for adequate sampling and for timely processing of specimens to maintain optimum performance.
Evaluation of the Affirm Ambient Temperature Transport System for the Detection and Identification of
Trichomonas vaginalis
,
Gardnerella vaginalis
, and
Candida
Species from Vaginal Fluid Specimens
Authors: Brown Haywood L. , Fuller DeAnna D. , Davis Thomas E. , Schwebke Jane R. , Hillier Sharon L. 
Published: July 2002

ABSTRACT

The objective of this study was to measure the performance of the Affirm Ambient Temperature Transport System (ATTS) over time and to estimate the length of time the system can preserve a vaginal specimen containing the three common organisms causing vaginitis:
Trichomonas vaginalis
,
Candida
species, and
Gardnerella vaginalis
(one of the causative agents of bacterial vaginosis). Women with symptoms of vaginitis presenting to one of three clinical centers were evaluated over a 4- to 8-week period. Four simultaneously obtained swabs were collected and tested by the Affirm VPIII assay at time zero with and without a preservative reagent, at 24 h with reagent, and at either 48 or 72 h with reagent. For each of the three organisms,
Trichomonas
,
Gardnerella
, and
Candida
, positivity at each time point was evaluated and compared to that at reference time zero with and without the ATTS. A total of 940 specimens were obtained from the three clinical sites. Eight hundred three were positive for one or more of the three organisms.
Gardnerella
had the highest overall positive rate (62%), followed by
Candida
with 18% and
Trichomonas
at 9%. The percent sensitivity versus control for
Trichomonas
ranged from 100% at time zero with and without reagent to 91% by 72 h.
Gardnerella
and
Candida
sensitivity remained at 100% for each time period. The Affirm VPIII ATTS system performed within 10% of the control swab (no transport reagent) at all four time points (0, 24, 48, and 72 h) for
Trichomonas
,
Gardnerella
, and
Candida
.
In Vitro Activities of Terbinafine in Combination with Fluconazole, Itraconazole, Voriconazole, and Posaconazole against Clinical Isolates of
Candida glabrata
with Decreased Susceptibility to Azoles
Authors: Perea Sofia , Gonzalez Gloria , Fothergill Annette W. , Sutton Deanna A. , Rinaldi Michael G. 
Published: July 2002

ABSTRACT

A checkerboard microdilution method, performed according to the recommendations of the National Committee for Clinical Laboratory Standards, was used to study the in vitro interaction of terbinafine (TRB) with fluconazole (FLU), itraconazole (ITRA), voriconazole (VRC), and posaconazole (PSZ) in 24 isolates of
Candida glabrata
with decreased susceptibility to azoles isolated from the oral cavities of human immunodeficiency virus patients. Synergy, defined as a fractional inhibitory concentration index of ≤0.5, was observed in 17% of TRB-FLU interactions, 21% of TRB-ITRA interactions, 33% of TRB-VRC interactions, and 12% of TRB-PSZ interactions. Where synergy was not achieved, there was still a decrease in the MIC of one or both drugs when used in combination. Antagonism was not observed in any drug combination. Clinical studies are warranted to elucidate the potential utility of these combination therapies.
Quantitative Detection of Respiratory
Chlamydia pneumoniae
Infection by Real-Time PCR
Authors: Kuoppa Yvonne , Boman Jens , Scott Lena , Kumlin Urban , Eriksson Iréne , Allard Annika 
Published: July 2002

ABSTRACT

Real-time PCR was evaluated as a quantitative diagnostic method for
Chlamydia pneumoniae
infection using different respiratory samples. Real-time PCR had efficiency equal to or better than that of nested touchdown PCR. This study confirmed sputum as the best sampling material to detect an ongoing
C. pneumoniae
infection.
Modification of the Cytoplasmic Domain of Influenza Virus Hemagglutinin Affects Enlargement of the Fusion Pore
Authors: Kozerski Christine , Ponimaskin Evgeni , Schroth-Diez Britta , Schmidt Michael F. G. , Herrmann Andreas 
Published: July 2002

ABSTRACT
The fusion activity of chimeras of influenza virus hemagglutinin (HA) (from A/fpv/Rostock/34; subtype H7) with the transmembrane domain (TM) and/or cytoplasmic tail (CT) either from the nonviral, nonfusogenic T-cell surface protein CD4 or from the fusogenic Sendai virus F-protein was studied. Wild-type or chimeric HA was expressed in CV-1 cells by the transient T7-RNA-polymerase vaccinia virus expression system. Subsequently, the fusion activity of the expression products was monitored with red blood cells or ghosts as target cells. To assess the different steps of fusion, target cells were labeled with the fluorescent membrane label octadecyl rhodamine B-chloride (R18) (membrane fusion) and with the cytoplasmic fluorophores calcein (molecular weight [MW], 623; formation of small aqueous fusion pore) and tetramethylrhodamine-dextran (MW, 10,000; enlargement of fusion pore). All chimeric HA/F-proteins, as well as the chimera with the TM of CD4 and the CT of HA, were able to mediate the different steps of fusion very similarly to wild-type HA. Quite differently, chimeric proteins with the CT of CD4 were strongly impaired in mediating pore enlargement. However, membrane fusion and formation of small pores were similar to those of wild-type HA, indicating that the conformational change of the ectodomain and earlier fusion steps were not inhibited. Various properties of the CT which may affect pore enlargement are considered. We surmise that the hydrophobicity of the sequence adjacent to the transmembrane domain is important for pore dilation.
Full-Length GB Virus C (Hepatitis G Virus) RNA Transcripts Are Infectious in Primary CD4-Positive T Cells
Authors: Xiang Jinhua , Wünschmann Sabina , Schmidt Warren , Shao Jianqiang , Stapleton Jack T. 
Published: July 2002

ABSTRACT
GB virus C (GBV-C or hepatitis G virus) is a recently described flavivirus which frequently leads to chronic viremia in humans. Although GBV-C is associated with acute posttransfusion hepatitis, it is not clear if the virus is pathogenic for humans. We constructed a full-length cDNA from the plasma of a person with chronic GBV-C viremia. Peripheral blood mononuclear cells (PBMCs) transfected with full-length RNA transcripts from this GBV-C clone resulted in viral replication. This was demonstrated by serial passage of virus from cell culture supernatants, detection of increasing concentrations of positive- and negative-sense GBV-C RNA over time, and the detection of the GBV-C E2 antigen by confocal microscopy. In addition, two types of GBV-C particles were identified in cell lysates; these particles had buoyant densities of 1.06 and 1.12 to 1.17 g/ml in sucrose gradients. PBMCs sorted for expression of CD4 contained 100-fold-more GBV-C RNA than CD4-negative cells. Taken together, these data demonstrate that RNA transcripts from GBV-C full-length cDNA are infectious in primary CD4-positive T cells. In contrast, RNA transcripts from an infectious hepatitis C virus clone did not replicate in the same cell culture system. Infectious RNA transcripts from GBV-C cDNA should prove useful for studying viral replication and may allow identification of differences between GBV-C and hepatitis C virus cultivation in vitro.
Mapping of Genetic Determinants of Rubella Virus Associated with Growth in Joint Tissue
Authors: Lund Karen D. , Chantler Janet K. 
Published: July 2002

ABSTRACT
Rubella virus (RV) strains vary in their abilities to replicate and persist in cell cultures derived from human joint tissue (synovial cells [SC]), and this arthrotropism appears to be linked to their association with joint symptoms in vivo. In order to map the genetic determinants of arthrotropism, an infectious clone of the Cendehill vaccine strain of RV was constructed, as well as two chimeric clones containing cDNAs from both Cendehill and Therien (wild-type) strains. Replacement of the entire structural gene region of Therien in the infectious clone pROBO302 with the corresponding region of Cendehill did not affect growth in SC. A further observation that Cendehill bound equally well to SC and the permissive Vero cell line indicated that restriction was not at the level of receptor binding, a function of the envelope proteins. Mutations that affected growth in joint cells were mapped to two locations in the nonstructural gene region. The first of these (nucleotides 2803 and 6416) resulted in a 10-fold decrease in yield of progeny virus from SC. This region contained five mutations, at nucleotides 2829, 3060, 3164, and 3528 (near the carboxy terminus of P150 where the protease domain is located) and at nucleotide 4350 in p90. Further substitution of the sequence representing nucleotides 1 to 2803 to give a complete Cendehill infectious clone restricted growth in SC by a further 100-fold to less than 10 PFU/ml. This region contains three mutations, at nucleotides 34, 37, and 55, within the 5′ stem-loop structure. In conclusion, the Cendehill-specific mutations believed to be determinants of joint cell growth are located in two regions, the 5′ nontranslated region and in a sequence that encodes the carboxy-terminal region of p150 extending into the helicase domain of p90.
CD21-Mediated Entry and Stable Infection by Epstein-Barr Virus in Canine and Rat Cells
Authors: Yang Lixin , Maruo Seiji , Takada Kenzo 
Published: July 2002

ABSTRACT

We developed an adenovirus vector for transduction of the human CD21 gene (Adv-CD21), the Epstein-Barr virus (EBV)-specific receptor on human B lymphocytes, to overcome the initial barrier of EBV infection in nonprimate mammalian cells. Inoculation of Adv-CD21 followed by exposure to recombinant EBV carrying a selectable marker resulted in the successful entry of EBV into three of seven nonprimate mammalian cell lines as evidenced by expression of EBV-determined nuclear antigen (EBNA). The EBV-susceptible cell lines included rat glioma-derived 9L, rat mammary carcinoma-derived c-SST-2, and canine kidney-derived MDCK. Subsequent selection culture with G418 yielded drug-resistant cell clones. In these cell clones, EBV existed as an episomal form, as evidenced through the Gardella gel technique. Among the known EBV latency-associated gene products, EBV-encoded small RNAs, EBNA1 and transcripts from the
Bam
HI-A rightward reading frame (BARF0), and latent membrane protein 2A were expressed in all EBV-infected cell clones. The viral lytic events could be induced in these cell clones by simultaneous treatment with 12-
O
-tetradecanoylphorbol-13-acetate and
n
-butyric acid, but they were abortive, and infectious virus was not produced. These results indicate that once the initial barrier for attachment is overcome artificially, EBV can establish a stable infection in some nonprimate mammalian cells, and they raise the possibility that transgenic animals with the human CD21 gene could provide an animal model for EBV infection.
The Level of CD4 Expression Limits Infection of Primary Rhesus Monkey Macrophages by a T-Tropic Simian Immunodeficiency Virus and Macrophagetropic Human Immunodeficiency Viruses
Authors: Bannert Norbert , Schenten Dominik , Craig Stewart , Sodroski Joseph 
Published: July 2002

ABSTRACTThe entry of primate immunodeficiency viruses into cells is dependent on the interaction of the viral envelope glycoproteins with receptors, CD4, and specific members of the chemokine receptor family. Although in many cases the tropism of these viruses is explained by the qualitative pattern of coreceptor expression, several instances have been observed where the expression of a coreceptor on the cell surface is not sufficient to allow infection by a virus that successfully utilizes the coreceptor in a different context. For example, both the T-tropic simian immunodeficiency virus (SIV) SIVmac239 and the macrophagetropic (M-tropic) SIVmac316 can utilize CD4 and CCR5 as coreceptors, and both viruses can infect primary T lymphocytes, yet only SIVmac316 can efficiently infect CCR5-expressing primary macrophages from rhesus monkeys. Likewise, M-tropic strains of human immunodeficiency virus type 1 (HIV-1) do not infect primary rhesus monkey macrophages efficiently. Here we show that the basis of this restriction is the low level of CD4 on the surface of these cells. Overexpression of human or rhesus monkey CD4 in primary rhesus monkey macrophages allowed infection by both T-tropic and M-tropic SIV and by primary M-tropic HIV-1. By contrast, CCR5 overexpression did not specifically compensate for the inefficient infection of primary monkey macrophages by T-tropic SIV or M-tropic HIV-1. Apparently, the limited ability of these viruses to utilize a low density of CD4 for target cell entry accounts for the restriction of these viruses in primary rhesus monkey macrophages.
Varicella-Zoster Virus Proteins in Skin Lesions: Implications for a Novel Role of ORF29p in Chickenpox
Authors: Annunziato Paula W. , Lungu Octavian , Panagiotidis Christos , Zhang Jing H. , Silvers David N. , Gershon Anne A. , Silverstein Saul J. 
Published: July 2002

ABSTRACT
Skin biopsy samples from varicella-zoster virus (VZV)-infected patients examined by immunohistochemistry demonstrated VZV replication in nonepithelial cell types. ORF29p, a nonstructural nuclear protein, was found in nerves of two of six patients with chickenpox. In tissue culture, ORF29p was secreted by VZV-infected fibroblasts. Extracellular ORF29p can be taken up through endocytosis by human neurons, implying a novel role for this protein in pathogenesis.
Herpes Simplex Virus Type 1-Specific Cytotoxic T-Lymphocyte Arming Occurs within Lymph Nodes Draining the Site of Cutaneous Infection
Authors: Jones Claerwen M. , Cose Stephen C. , Coles Richard M. , Winterhalter Adam C. , Brooks Andrew G. , Heath William R. , Carbone Francis R. 
Published: July 2002

ABSTRACTVarious studies have shown that major histocompatibility complex class I-restricted cytotoxic T lymphocytes (CTL) can be isolated from lymph nodes draining sites of cutaneous infection with herpes simplex virus type 1 (HSV-1). Invariably, detection of this cytolytic activity appeared to require some level of in vitro culture of the isolated lymph node cells, usually for 3 days, in the absence of exogenous viral antigen. This in vitro “resting” period was thought to represent the phase during which committed CD8+T cells become “armed” killers after leaving the lymph nodes and prior to their entry into infected tissue as effector CTL. In this study we reexamined the issue of CTL appearance in the HSV-1 immune response and found that cytolytic activity can be isolated directly from draining lymph nodes, although at levels considerably below those found after in vitro culture. By using T-cell receptor elements that represent effective markers for class I-restricted T cells specific for an immunodominant glycoprotein B (gB) determinant from HSV-1, we show that the increase in cytotoxicity apparent after in vitro culture closely mirrors the expansion of gB-specific CTL during the same period. Taken together, our results suggest that HSV-1-specific CTL priming does not appear to require any level of cytolytic machinery arming outside the lymph node compartment despite the absence of any detectable infection within that site.
Hepadnavirus Infection in Captive Gibbons
Authors: Lanford Robert E. , Chavez Deborah , Rico-Hesse Rebeca , Mootnick Alan 
Published: July 2002

ABSTRACT
The recent isolation of a nonhuman primate hepadnavirus from woolly monkeys prompted an examination of other primates for potentially new hepadnaviruses. A serological analysis of 30 captive gibbons revealed that 47% were positive for at least one marker of ongoing or previous infection with a hepatitis B virus (HBV). The amino acid sequences of the core and surface genes of human and gibbon virus isolates were very similar. Phylogenetic analysis indicated that the gibbon isolates lie within the human HBV family, indicating that these HBV isolates most likely stem from infection of gibbons from a human source.
Detection and Characterization of Porcine Endogenous Retrovirus in Porcine Plasma and Porcine Factor VIII
Authors: Takefman Daniel M. , Wong Susan , Maudru Thomas , Peden Keith , Wilson Carolyn A. 
Published: July 2002

ABSTRACT

The pig genome contains porcine endogenous retroviruses (PERVs) capable of infecting human cells. Detection of infectious retrovirus in porcine peripheral blood mononuclear cells and endothelial cells suggested to us that pig plasma is likely to contain PERV. Both PERV
env
sequences and viral reverse transcriptase (RT) activity were detected in all plasma samples isolated from four NIH minipigs. To detect infectious virus from plasma, we performed a culture assay using three cell lines of feline, swine, and human origin that had previously been shown to be permissive for PERV. Infectious virus was successfully cultured from all four NIH minipig plasmas on the swine cell line ST-IOWA. Using RT-PCR with
env
-specific primers, we could detect expression of PERV class C envelope in the supernatant of ST-IOWA cells that had been exposed to each pig plasma. We next examined a pig plasma derivative, Hyate:C (porcine factor VIII), and found evidence of PERV particles, since all six lots examined were positive for PERV RNA and RT activity. However, infectious virus could not be detected in clinical lots of Hyate:C, suggesting that the manufacturing process might reduce the load of infectious virus to levels below detectable limits of the assay. Detection of infectious virus in porcine plasma confirms and extends the previous findings that certain porcine cells express PERV when manipulated in vitro and clearly demonstrates that there are porcine cells that express infectious PERV constitutively in vivo.
B2 but Not B1 Cells Can Contribute to CD4+T-Cell-Mediated Clearance of Rotavirus in SCID Mice
Authors: Kushnir Natasha , Bos Nicolaas A. , Zuercher Adrian W. , Coffin Susan E. , Moser Charlotte A. , Offit Paul A. , Cebra John J. 
Published: July 2002

ABSTRACTStudies utilizing various immunodeficient mouse models of rotavirus (RV) infection demonstrated significant roles of RV-specific secretory immunoglobulin A (IgA), CD4+T cells, and CD8+T cells in the clearance of RV and protection from secondary infection. Secretion of small but detectable amounts of IgA in RV-infected αβ T-cell receptor knockout mice (11) and distinctive anatomical localization and physiology of B1 cells suggested that B1 cells might be capable of producing RV-specific intestinal IgA in a T-cell-independent fashion and, therefore, be responsible for ablation of RV shedding. We investigated the role of B1 cells in the resolution of primary RV infection using a SCID mouse model. We found that the adoptive transfer of unseparated peritoneal exudate cells ablates RV shedding and leads to the production of high levels of RV-specific intestinal IgA. In contrast, purified B1 cells do not ablate RV shedding and do not induce a T-cell-independent or T-cell-dependent, RV-specific IgA response but do secrete large amounts of polyclonal (total) intestinal IgA. Cotransfer of mixtures of purified B1 cells and B1-cell-depleted peritoneal exudate cells differing in IgA allotypic markers also demonstrated that B2 cells (B1-cell-depleted peritoneal exudate cells) and not B1 cells produced RV-specific IgA. To our knowledge, this is the first observation that B1 cells are unable to cooperate with CD4+T cells and produce virus-specific intestinal IgA antibody. We also observed that transferred CD4+T cells alone are capable of resolving RV shedding, although no IgA is secreted. These data suggest that RV-specific IgA may not be obligatory for RV clearance but may protect from reinfection and that effector CD4+T cells alone can mediate the resolution of primary RV infection. Reconstitution of RV-infected SCID mice with B1 cells results in the outgrowth of contaminating, donor CD4+T cells that are unable to clear RV, possibly because their oligoclonal specificities may be ineffective against RV antigens.
Novel, Soluble Isoform of the Herpes Simplex Virus (HSV) Receptor Nectin1 (or PRR1-HIgR-HveC) Modulates Positively and Negatively Susceptibility to HSV Infection
Authors: Lopez Marc , Cocchi Francesca , Avitabile Elisa , Leclerc Annouck , Adelaide Jose , Campadelli-Fiume Gabriella , Dubreuil Patrice 
Published: July 2002

ABSTRACT
A novel member of the nectin family, nectin1γ, was molecularly cloned. The cDNA has the same ectodomain as nectin1α and nectin1β, the two known transmembrane isoforms that serve as receptors for herpes simplex virus (HSV) entry into human cell lines (nectin1α and nectin1β, also called PRR1-HveC and HIgR, respectively). The 1.4-kb transcript, which originated by alternative splicing, is expressed in human cell lines, and appears to have a narrow distribution in human tissues. The sequence does not have a hydrophobic anchoring region, and the protein is secreted in the culture medium of cells transfected with the cDNA. Nectin1γ, purified from culture medium, can compete with membrane-bound nectin1β and reduce HSV infectivity. The expression of nectin1γ cDNA in cells resistant to HSV infection and lacking HSV receptors enables HSV to enter the cell, which implies that it is present at the cell surface. Thus, nectin1γ has the potential both to mediate and to reduce HSV entry into cells.