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:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The reverse transcriptase-polymerase chain reaction and the nested polymerase chain reaction were used for detection of respiratory syncytial virus (RSV) sequences in middle ear effusions collected from children with otitis media. Sequences of RSV were detected in 21 of 34 samples tested. These samples were collected during and/or after natural outbreaks of RSV infection in the community. In those patients from whose nasopharynges RSV was isolated, the viral sequences were highly detectable (75%) in the effusions. These observations suggest RSV as an important factor in the pathogenesis of otitis media with effusion.
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PMID:Detection of genomic sequences of respiratory syncytial virus in otitis media with effusion in children. 141 57

In vivo preinfection of chicks with rabies virus (RV) or vesicular stomatitis virus (VSV) ts 1026 inhibits tumour formation after superinfection with Rous sarcoma virus (RSV). The degree of inhibition depends on the titre of the infecting viruses and the interval between rhabdovirus and RSV infection. In vitro, cells preinfected with VSV ts 1026 under non-permissive conditions and superinfected with RSV, are not transformed as judged by cell morphology, serum requirement for growth or the capacity to form colonies in soft agar, all these being the same as in uninfected cells. Doubly infected cells take up less deoxyglucose than cells infected with RSV only and more than cells infected with VSV only. RSV multiplication in inhibited in doubly infected cells: the supernatant fluid of these cells contains fewer focus-forming units and less reverse transcriptase activity than that of cells infected with RSV only. Doubly infected cells contain both VSV and RSV internal antigens 15 days after infection. The supernatant fluid of cells infected with VSV and maintained under non-permissive conditions inhibits transformation by RSV and multiplication of RSV, but not of VSV. Under non-permissive conditions, the rhabdoviruses undergo at least part of the infectious cycle, but no infectious virus is produced. RV antigen can be detected in the brain of parenterally infected chicks and VSV antigen in cells infected 15 days previously. We conclude that the inhibition of RSV multiplication and expression is probably due to one or more processes linked to the persistence of rhabdovirus components and that it cannot be attributed exclusively to interferon.
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PMID:Inhibition of Rous sarcoma virus-induced transformation by preinfection with rhabdoviruses. 630 Feb 84

The induction of immunoregulatory cytokines IL-1 beta, IL-6, IL-12, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) was studied with neonatal (cord blood) monocyte-derived macrophages (MDM) after in vitro infection with respiratory syncytial virus (RSV). The expression of mRNAs for these cytokines in RSV-infected MDM was examined by reverse transcriptase-polymerase chain reaction (RT-PCR). The activities of these cytokines were assayed by ELISA. Significant increase of expression of mRNA for IL-6, IL-12, TNF-alpha and IFN-gamma occurred within 2 h after infection and decreased within 6 h after infection. At 20 h after infection the MDM produced and secreted moderate levels of IL-6 and TNF-alpha; however, no IL-12 and IFN-gamma activities were detected. Moderate IL-1 beta mRNA was expressed before RSV infection, and its expression increased at 2 h after infection. However, no detectable IL-1 beta was secreted in culture fluids. These observations suggest that RSV-infected neonatal macrophages produce and secrete IL-6 and TNF-alpha quickly during the eclipse phase of RSV infection and therefore may play a prominent role in the initiation of the immune response to RSV.
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PMID:Respiratory syncytial virus-induced cytokine production by neonatal macrophages. 897 10

Paired samples of milk and serum collected 3 days postpartum from 20 women were tested for the presence and level of interleukin (IL)-1, IL-6, IL-12, tumor necrosis factor alpha (TNF-alpha), and interferon-gamma (IFN-gamma) by enzyme immunoassay. The expression of these cytokine mRNAs in milk macrophages from eight donors were semiquantitatively analyzed by reverse transcriptase-polymerase chain reaction. The effects of respiratory syncytial virus (RSV) infection on cytokine production were determined in five samples of milk macrophages. Over 90% of the milk samples tested exhibited detectable levels of IL-1beta, IL-6, and TNF-alpha. No IL-12 or IFN-gamma activity was detected in the milk. IL-6 activity was weakly detected in about 45%, and TNF-alpha activity in about 10% of the serum samples tested. However, no IL-1beta, IL-12, or IFN-gamma activity was demonstrated in any of the serum samples. Milk macrophages from eight subjects all exhibited mRNA for IL-1beta, TNF-alpha, and IL-6, and IFN-gamma mRNA in six of eight subjects, although no IFN-gamma was detected in any of the 20 samples of milk tested. RSV exposure resulted in a 2- to 100-fold increase in the expression of IL-1beta, IL-6, and TNF-alpha mRNA as well as cytokine protein. Although RSV infection enhanced the expression of IFN-gamma mRNA, no detectable IFN-gamma was produced by the milk macrophages. These observations suggest that the milk macrophages are actively engaged in the physiological production of IL-1beta, IL-6, TNF-alpha, and IFN-gamma in the mammary gland and continue to possess the capacity to increase production of these cytokines in response to RSV and possibly other viral infections.
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PMID:Enhanced cytokine production by milk macrophages following infection with respiratory syncytial virus. 912 13

Interleukin-1beta (IL-1beta) production in response to respiratory syncytial virus (RSV) was investigated in normal neonate monocytes. Intracellular or culture supernatant IL-1beta protein levels were measured by enzyme immunoassay. The expression of mRNAs for interferon regulatory factor 1 (IRF-1), IL-1beta-converting enzyme (ICE), and IL-1beta in the cells was analyzed semiquantitatively by reverse transcriptase-PCR. Before RSV exposure, some IRF-1, ICE, and IL-1beta transcripts were already expressed in the monocytes. The levels of these transcripts increased significantly 2 h after RSV exposure compared with those in mock-infected cells. At that time, significantly higher intracellular IL-1beta protein levels were observed in RSV-exposed cells. After 20 h of RSV exposure, quantities of soluble IL-1beta secreted from RSV-exposed cells were moderately higher than those from noninfected cells. These observations suggest that RSV infection of neonatal monocytes triggers enhanced transcription and increased translation of the IL-1beta gene and increased secretion of the soluble protein. The later phase of these processes may be promoted by ICE activity, which was upregulated by increased IRF-1. The increase in IRF-1 activity may also result from RSV infection.
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PMID:Respiratory syncytial virus infection of neonatal monocytes stimulates synthesis of interferon regulatory factor 1 and interleukin-1beta (IL-1beta)-converting enzyme and secretion of IL-1beta. 942 Feb 96

The induction kinetics of the transcriptional activities of interferon regulatory factor 1 (IRF-1), interleukin-1beta-converting enzyme (ICE), and CPP32 by respiratory syncytial virus (RSV) infection of human type II alveolar epithelial cells (A549 cells) were analyzed semiquantitatively by reverse transcriptase PCR. The appearance of ICE and CPP32 protein in cell lysate was examined by Western blotting analysis. The induction of apoptosis by RSV infection was examined by the appearance of DNA fragmentation detected by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling. RSV moderately enhanced IRF-1 mRNA as early as 4 h after infection, and this enhancement lasted several hours. Following induction of the IRF-1 gene, ICE gene expression increased significantly, and an increase of ICE protein was observed in the RSV-infected cell lysate. These increments were observed in cells treated with live RSV but not in cells treated with inactivated RSV or control antigen. However, no infection-specific increase of CPP32 gene expression or the protein was observed. No nucleosomal fragmentation was observed in RSV-infected cells during the whole course of infection, despite the appearance of extensive cytopathic change and cell death. These observations suggest that RSV infection of human alveolar epithelial cells induces the ICE gene and its protein as a result of increased IRF-1 induction but that the increased ICE was insufficient to cause apoptosis in the RSV-infected cells. ICE might not be able to activate CPP32, which is thought to be the more important protease for apoptosis.
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PMID:Respiratory syncytial virus infection of human alveolar epithelial cells enhances interferon regulatory factor 1 and interleukin-1beta-converting enzyme gene expression but does not cause apoptosis. 955 48

Respiratory syncytial virus (RSV) infection is now recognised as a significant problem in elderly adults. Epidemiological evidence indicates the impact of RSV in older adults may be similar to non-pandemic influenza, both in the community and in long-term care facilities. Attack rates in nursing homes are approximately 5-10% per year with significant rates of pneumonia (10-20%) and death (2-5%). Estimates using US health care databases and viral surveillance results over a 9-year period indicate that RSV infection causes approximately 10,000 all-cause deaths annually among persons >64 years of age. In contrast, influenza A accounted for approximately 37,000 yearly deaths in the same age group. The clinical features of RSV infection may be difficult to distinguish from those of influenza but include nasal congestion, cough, wheezing and low-grade fever. Older persons with underlying heart and lung disease and immunocompromised patients are at highest risk for RSV infection-related pneumonia and death. Diagnosis of RSV infection in adults is difficult because viral culture and antigen detection are insensitive, presumably because of low viral titres. The combination of serology and reverse transcriptase polymerase chain reaction assay offers the best sensitivity and specificity for the diagnosis of RSV but unfortunately these techniques are not widely available; consequently, most adult RSV disease goes unrecognised. Although treatment of RSV infection in the elderly is largely supportive, early therapy with ribavirin and intravenous gamma-globulin improves survival in immunocompromised persons. An effective RSV vaccine has not yet been developed. Therefore, prevention of RSV is limited to standard infection control practices, such as hand washing and the use of gowns and gloves.
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PMID:Respiratory syncytial virus infection in elderly adults. 1603 73

The present study was performed to elucidate the clinical outcome, and etiology of acute otitis media (AOM) in children based on virologic and bacteriologic tests. The study group consisted of 120 children aged 6 to 144 months with AOM. Middle ear fluid (MEF) was tested for viral pathogens by reverse transcriptase polymerase chain reaction (RT-PCR) and for bacteria by gram-staining and culture. Clinical response was assessed on day 2 to 4, 11 to 13, 26 to 28. Respiratory viruses were isolated in 39 patients (32.5%). Respiratory syncytial virus (RSV) (46.5%) was the most common virus identified in MEF samples, followed by human rhinovirus (HRV) (25.6%), human coronavirus (HCV) (11.6%), influenza (IV) type A (9.3%), adenovirus type sub type A (AV) (4%), and parainfluenza (PIV) type -3 (2%) by RT-PCR. In total 69 bacterial species were isolated from 65 (54.8%) of 120 patients. Streptococcus pneumoniae (S. pneumoniae) was the most frequently isolated bacteria. Viral RNA was detected in 31 (56.3%) of 55 bacteria-negative specimens and in 8 (12.3%) of 65 bacteria-positive MEF samples. No significant differences were found between children representing viral infection alone, combined viral and bacterial infection, bacterial infection alone, and neither viral nor bacterial infection, regarding clinical cure, relapse and reinfection rates. A significantly higher rate of secretory otitis media (SOM) was observed in alone or combined RSV infection with S. pneumonia or Haemophilus influenzae (H. influenzae) than in other viruses infection. Conclusion. This study provides information about etiologic agents and diagnosis of AOM in Turkish children. The findings highlight the importance of common respiratory viruses and bacterial pathogens, particularly RSV, HRV, S. pneumoniae and H. influenzae, in predisposing to and causing AOM in children.
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PMID:Acute otitis media and respiratory viruses. 1696 96

One hundred years ago Peyton Rous recovered a virus, now known as the Rous sarcoma virus (RSV), from a chicken sarcoma, which reproduced all aspects of the tumor on injection into closely related chickens. There followed recovery of causal viruses of tumors of different morphology from 4 more of 60 chicken tumors. Subsequent studies in chickens of the biology of the first RSV isolated moved slowly for 45 y until an assay of ectodermal pocks of the chorioallantoic membrane of chicken embryos was introduced. The inadequacies of that assay were resolved with the production of transformed foci in cultures of chicken fibroblasts. There followed a productive period on the dynamics of RSV infection. An avian leukosis virus (ALV) was found in some chicken embryos and named resistance-inducing factor (RIF) because it interferes with RSV. Its epidemiology in chickens is described. Another ALV was found in stocks of RSV and called Rous-associated virus (RAV). Cells preinfected with RAV interfere with RSV infection, but RSV does not produce infectious virus unless RAV is added during or after RSV infection. Intracellular RAV provides the infectious coat for the otherwise defective RSV. The coat determines the antigenicity, host range, and maturation rate of RSV. RSV particles carry reverse transcriptase, an enzyme that converts their RNA into DNA and allows integration into the cell's DNA, where it functions as a cellular gene. This was the bridge that joined the biological era to the molecular era. Its relation to oncogenes and human cancer is discussed.
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PMID:The early history of tumor virology: Rous, RIF, and RAV. 2181 62

Respiratory syncytial virus (RSV) rapid antigen detection tests (RADT) are extensively used in clinical laboratories. We performed a systematic review and meta-analysis to evaluate the accuracy of RADTs for diagnosis of RSV infection and to determine factors associated with accuracy estimates. We searched EMBASE and PubMed for diagnostic-accuracy studies of commercialized RSV RADTs. Studies reporting sensitivity and specificity data compared to a reference standard (reverse transcriptase PCR [RT-PCR], immunofluorescence, or viral culture) were considered. Two reviewers independently extracted data on study characteristics, diagnostic-accuracy estimates, and study quality. Accuracy estimates were pooled using bivariate random-effects regression models. Heterogeneity was investigated with prespecified subgroup analyses. Seventy-one articles met inclusion criteria. Overall, RSV RADT pooled sensitivity and specificity were 80% (95% confidence interval [CI], 76% to 83%) and 97% (95% CI, 96% to 98%), respectively. Positive- and negative-likelihood ratios were 25.5 (95% CI, 18.3 to 35.5) and 0.21 (95% CI, 0.18 to 0.24), respectively. Sensitivity was higher in children (81% [95% CI, 78%, 84%]) than in adults (29% [95% CI, 11% to 48%]). Because of this disparity, further subgroup analyses were restricted to pediatric data (63 studies). Test sensitivity was poorest using RT-PCR as a reference standard and highest using immunofluorescence (74% versus 88%; P < 0.001). Industry-sponsored studies reported significantly higher sensitivity (87% versus 78%; P = 0.01). Our results suggest that the poor sensitivity of RSV RADTs in adults may preclude their use in this population. Furthermore, industry-sponsored studies and those that did not use RT-PCR as a reference standard likely overestimated test sensitivity.
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PMID:Diagnostic Accuracy of Rapid Antigen Detection Tests for Respiratory Syncytial Virus Infection: Systematic Review and Meta-analysis. 2635 16


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