Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.48 (transcriptase)
9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Human immunodeficiency virus (HIV) production continues in patients receiving highly active antiretroviral therapy (HAART) with undetectable (<50 copies/mL) virus loads. Our initial cross-sectional study showed that this viremia is composed of viruses that lack new resistance mutations to the HAART regimen. Here we describe a longitudinal, clonal genotypic analysis of plasma virus loads in treated adults who had undetectable virus loads. We document a continuous production of virus in 8 HIV-1-infected adults who maintained suppression of viremia for up to 15 months. Using analytical approaches for distinguishing selected resistance mutations from nonselected mutations and polymerase chain reaction errors, we detected no evolution of resistance in the reverse-transcriptase and protease genes. Sporadic resistance mutations were detected in some viral clones that were not selected for subsequently. Thus, in some patients, HAART suppresses replication to a level that does not allow the evolution of drug resistance over a time frame of years.
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PMID:Genotypic analysis of HIV-1 drug resistance at the limit of detection: virus production without evolution in treated adults with undetectable HIV loads. 1507 83

Although randomized trials have shown enhancement of efficacy for combination therapy with interferon (IFN) alpha-2b and ribavirin compared with IFN monotherapy as first-line treatment for chronic hepatitis C, infection with genotype 1b and high viremia are still associated with significantly low response rates compared with non-1 genotypes and low viremia. We analysed amino acid sequences of the viral RNA-dependent RNA polymerase (RdRP) or nonstructural protein 5B (NS5B), responsible for ribavirin misincorporation into RNA products in patients with genotype 1b-related chronic hepatitis C and high viremia, and examined the relationship between such RdRp polymorphisms, and the initial decline in viral load induced by combination therapy with IFN-alpha and ribavirin. Substitution of glutamic acid to lysine at the 124th position (E124K) and of isoleucine to valine at the 85th position (I85V) were found to be closely associated with a potent decline of viral load and viral clearance at 8 weeks of treatment (five of five patients, coincidence rate 100%). In conclusion, our results suggest that the polymorphisms of E124K and I85V identified in NS5B protein are crucial for early viral clearance in patients with genotype 1b and high viremia by combination therapy with IFN and ribavirin, and that detection of amino acid sequence motifs might enable prediction of clinical efficacy.
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PMID:Polymorphisms of NS5B protein relates to early clearance of hepatitis C virus by interferon plus ribavirin: a pilot study. 1511 24

In summer 2001, Usutu virus (USUV), a mosquito-borne flavivirus, was isolated for the first time in Europe during a mortality incident among Eurasian blackbirds (Turdus merula) in Austria. Chickens are frequently used as sentinel animals for arbovirus surveillance systems. In the present study, the pathogenicity of USUV for specific pathogen free chickens was investigated. Ten 2-week-old chickens were inoculated intravenously with 0.1 ml inoculum containing 10(3) median (50%) tissue culture infectious dose of USUV strain Vienna 2001-blackbird (939/01). Clinical signs, viraemia, gross and microscopic lesions, contact transmission and immunological response were evaluated. No clinical signs were observed in the USUV-inoculated animals during the experimental period. Pathological examination showed moderate splenomegaly and follicular infiltrates in the liver of several inoculated animals. Mild non-suppurative encephalitis was observed in the brain tissue of one virus-inoculated chicken examined 7 days post inoculation (d.p.i.). USUV nucleic acid was detected by reverse-transcriptase polymerase chain reaction in the organs of six inoculated chickens, although immunohistochemistry for flavivirus antigen was negative in all tissues from all chickens. Virus shedding was shown in three inoculated birds by detecting USUV RNA in cloacal swabs of two chickens at 5 d.p.i., and in the cloacal and pharyngeal swabs of one chicken at 7 d.p.i. Based on detection of viral RNA in peripheral blood mononuclear cells, viraemia was detected only in two chickens (at 7 d.p.i.). Only one of the inoculated chickens developed an antibody response. There was no evidence of virus transmission to chickens kept in contact with inoculated birds. No USUV was isolated from in-contact birds and all in-contact and control animals lacked USUV-specific antibodies. The present data suggest that domestic chickens are not at risk of developing clinical disease following USUV infection and that chickens are unlikely to be useful for sentinel purposes in USUV surveillance programmes.
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PMID:Limited pathogenicity of Usutu virus for the domestic chicken (Gallus domesticus). 1623 70

In June 2006, 150 wild common carp were sampled from Hamilton Harbour, Lake Ontario, Canada. Tissue pools consisting of kidney, spleen and encephalon were screened for viruses as a condition facilitating the export of live carp to France. Cytopathic effect (CPE), indicative of a viral infection, became evident after 8 days of incubation at 15 degrees C. Eighteen of 30 tissue pools (five fish per pool) eventually demonstrated viral CPE. The viral pathogen was initially cultured and isolated on the epithelioma papulosum cyprini cell line and subsequently shown to produce CPE in the fathead minnow and bluegill fin cell lines. Electron microscopy demonstrated the virus to be a rhabdovirus. Reverse transcriptase-polymerase chain reaction assay and nucleotide sequence analysis identified the isolate as spring viraemia of carp virus (SVCV). Phylogenetic analysis of a 533 bp region of the glycoprotein gene grouped the Canadian isolate in SVCV genogroup Ia together with isolates from Asia and the USA. Sequence comparisons revealed the Hamilton Harbour, Lake Ontario isolate to be most similar to an isolate obtained from common carp in the Calumet Sag Channel in Illinois in 2003 (98.9% nucleotide identity). This is the first report of the detection of SVCV in Canada.
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PMID:First detection and confirmation of spring viraemia of carp virus in common carp, Cyprinus carpio L., from Hamilton Harbour, Lake Ontario, Canada. 1795 10

To asses the role of virus load in the pathogenesis of hemorrhagic fever with renal syndrome, the serum Dobrava virus RNA load in 46 patients was measured with a novel quantitative real-time reverse-transcriptase polymerase chain reaction assay and compared to the disease severity. The level of viremia, detected in 26 patients, ranged from 10(2)-10(8) copies/mL of serum. The patients with severe disease had, on average, higher viral RNA loads than patients with a milder course of disease (6.15 vs. 4.67 log(10) copies/mL; P = .053). These results suggest that the Dobrava virus load might be associated with the severity of disease.
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PMID:Dobrava virus RNA load in patients who have hemorrhagic fever with renal syndrome. 1826 19

Five monoclonal antibodies (mAbs) against spring viraemia of carp (SVCV0504, isolated from common carp in China) were produced from mice immunized with purified virus preparations. The virion of SVCV contains five structural proteins, representing the nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G) and RNA-dependent RNA polymerase (L). Western blotting analysis revealed that three mAbs (1H5, 1E10, and 1H7) recognized specifically to a single protein of 47kDa (N), the mAb 3G4 reacted with two SVCV0504 proteins of 69kDa (G) and 47kDa (N), while the mAb 1A9 reacted with three SVCV0504 proteins of 69kDa (G), 50kDa (P), and 47kDa (N). By indirect ELISA, two mAbs (1H5 and 1H7) showed cross-reactivity with pike fry rhabdovirus (PFRV), but no cross-reactions with the Siniperca chuatsi rhabdovirus (SCRV), Scophthalmus maximus rhabdovirus (SMRV), Paralichthys olivaceus rhabdovirus (PoRV) were demonstrated with the five mAbs. Indirect immunofluorescence showed intense fluorescence in the cytoplasm of the SVCV0504-infected epithelioma papulosum cyprini (EPC) cells in areas corresponding to the location of granular structures. The sucrose gradient-purified SVCV0504 particles could be detected successfully by these mAbs using immunodot blotting. mAb 1A9 could completely neutralize 100 TCID(50) (50% tissue culture infective dose) of SVCV0504 at a dilution of 1:8. This is the first report of development of the neutralizing mAbs against SVCV. The mAb 1A9 was analyzed further and could be used to successfully detect viral antigens in the infected-EPC cell cultures or in cryosections from experimentally infected crucian carp (Carassius auratus) by immunohistochemistry assay. Furthermore, a flow cytometry procedure for the detection and quantification of cytoplasmic SVCV0504 in cell cultures was developed with mAb 1A9. At 28h after inoculation with the virus (0.01PFU/cell), 10.12% of infected cells could be distinguished from the uninfected cells. These mAbs will be useful in diagnostic test development and pathogenesis studies for fish rhabdovirus.
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PMID:Development and characterization of monoclonal antibodies to spring viraemia of carp virus. 1837 3

Rhesus macaque rhadinovirus (RRV) is closely related to Kaposi sarcoma-associated herpesvirus (KSHV) and is associated with the development of B-cell hyperplasia and persistent lymphadenopathy resembling multicentric Castleman disease in rhesus macaques (RMs) coinfected with simian immunodeficiency virus (SIV). Here we investigated whether RMs experimentally infected with SIV and RRV can develop other disease manifestations observed in HIV- and KSHV-infected patients. As reported earlier, inoculation of SIV-infected RMs with RRV results in persistent RRV infection, whereas immunocompetent animals infected with RRV exhibit viremia 2 weeks after infection, followed by a period of no virus detection until they are subsequently made immunodeficient by SIV infection. A subset of animals developed abnormal cellular proliferations characterized as extranodal lymphoma and a proliferative mesenchymal lesion. In situ hybridization and immunohistochemistry analysis indicate RRV is present in both malignancies, and DNA microarray analysis detected viral interleukin-6 (vIL-6) and viral FLICE-like inhibitory protein (vFLIP) transcripts. Reverse-transcriptase polymerase chain reaction analysis confirmed vIL-6 and vFLIP expression, and that of RRV open reading frames 72 and 73, homologs of KSHV open reading frames shown to be expressed in primary effusion lymphoma. These data support the utility of the RRV-/SIV-infected RM as an excellent animal model to investigate KSHV-like pathogenesis.
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PMID:Rhesus macaque rhadinovirus-associated non-Hodgkin lymphoma: animal model for KSHV-associated malignancies. 1875 78

The objectives of this experiment were to determine how long porcine reproductive and respiratory syndrome virus (PRRSV) could be detected in muscle tissues of experimentally infected pigs and to evaluate the transmissibility of PRRSV to pigs via ingestion of quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR)-positive muscle tissues. Serum, lymphoid tissues, and muscle (M. longissimus dorsi) samples were collected from 135 pigs (89 PRRSV-inoculated pigs and 46 negative control). Between 28 and 202 days post-inoculation, 13 of 89 (14.6%) muscle samples were positive by qRT-PCR. Among these 13, PRRSV was isolated from four of the 13 corresponding serum samples and three of 13 lymphoid tissue samples. In addition, infectious virus was detected in lymphoid tissue homogenates of six of 13 pigs by intramuscular bioassay. Swine transmissibility studies were performed by feeding thirteen 3-week-old PRRSV-naive pigs (recipient pigs) qRT-PCR-positive muscle and then monitoring recipients for evidence of PRRSV viremia by qRT-PCR. No transmission of PRRSV to recipient pigs via consumption of muscle samples was observed. These data suggested that qRT-PCR detected non-infectious PRRSV in pig meat and/or PRRSV is not highly transmissible to susceptible pigs via consumption of PRRSV-contaminated meat.
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PMID:Evaluation of the risk of PRRSV transmission via ingestion of muscle from persistently infected pigs. 1877 59

A significant obstacle to the prevention and control of porcine reproductive and respiratory syndrome virus (PRRSV) is the inability of current diagnostic tests to provide information concerning the stage of PRRSV infection. To explore possible prognostic combinations of cell-mediated and humoral immune responses, 3-week-old pigs (n=10) were intramuscularly (IM) inoculated with PRRSV isolate VR-2332 and followed for 193 days post-inoculation (DPI). Negative control pigs (n=10) were IM inoculated with minimum essential medium (MEM). At approximately 2-week intervals, blood samples were collected from all animals and tested for the number of interferon (IFN)-gamma-secreting peripheral blood mononuclear cells (enzyme-linked immunosorbent spot, Elispot), PRRSV viremia (quantitative reverse-transcriptase polymerase chain reaction, qRT-PCR), and serum antibodies using PRRSV protein ELISAs (N, GP5 3', GP5 5', M 5', M 3', GP5-M, and nsp2p) and a commercial PRRSV ELISA (IDEXX Laboratories Inc.). All pigs were viremic by 7 days post-inoculation, with 50% of the pigs resolving viremia by 56 DPI. A PRRSV-specific IFN-gamma response was detected at DPI 28, reached a plateau at 42 DPI, declined slightly, and remained relatively stable from 56 to 193 DPI. On the basis of ROC area under the curve (AUC) analysis, the ELISAs that most reliably differentiated PRRSV-inoculated pigs from negative control pigs were the commercial ELISA (AUC=0.97), the N ELISA (AUC=0.96), and the M 3' ELISA (AUC=0.93). Multivariate analyses were performed to evaluate the relationship between the immune response and the duration and level of viremia. With all antibody assays and Elispot included in the models, the analysis determined that the serum-virus neutralizing antibody response was the best predictor of both level and duration of viremia. It was concluded that humoral antibody responses, particularly the commercial ELISA, N ELISA, and M 3' ELISA were good predictors of prior exposure to PRRSV, but provided little information regarding the ontogeny of the protective immune response. Likewise, cell-mediated immunity based on the number of IFN-gamma-secreting lymphocytes was a poor prognosticator of PRRSV infection status.
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PMID:Immune response against porcine reproductive and respiratory syndrome virus during acute and chronic infection. 1883 44

Essential mixed cryoglobulinemia (type II) has turned out to be secondary to hepatitis C virus (HCV) infection in the large majority of patients. Interferon might be anticipated to be effective only in HCV-associated cryoglobulinemias. We found that interferon was highly effective in an HCV-positive patient with true essential type II mixed cryoglobulinemia. The patient presented with symptomatic cryoglobulinemic vasculitis without underlying immunologic, infectious, or neoplastic diseases. Tests for HCV viremia, a reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay, and anti-HCV antibodies (third-generation assays) were positive before therapy. The patient had severe cryoglobulinemic vasculitis with purpura, peripheral neuropathy, and membranous proliferative glomerulonephritis. The cryocrit before therapy was 6 percent in the patient. Recombinant interferon alfa-2a (Roferon-A, Hoffmann-LaRoche, Basel, Switzerland) was administered at a dose of 3 million units per day for three months and 3 million units every other day for the subsequent nine months, a protocol adopted for HCV-associated cryoglobulinemia. The patient had a complete clinical response, with the disappearance of serum cryoglobulins and all signs of cutaneous vasculitis and with the normalization of kidney-function results and urinary values in the patient with nephropathy. The patient has remained in complete remission for more than one year since the withdrawal of therapy. True essential mixed cryoglobulinemia with HCV infection complicated with glomerulonephritis represents a therapeutic challenge.
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PMID:Hepatitis C virus-associated type II mixed cryoglobulinemia vasculitis complicated with membranous proliferative glomerulonephritis. 1921 13


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