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)

Epizootiologic outbreaks of disseminated neoplasia have been reported in association with massive mortalities of various bivalve species. In cockles, Cerastoderma edule, this pathological condition was described in Ireland and France. Since 1997, different populations affected by this pathology have been detected in Galicia (NW Spain). Transmission electron microscopy allowed the visualization of virus-like particles in neoplastic cells, resembling a retrovirus-like agent. To confirm this hypothesis, we used a commercial kit for detection and quantification of reverse transcriptase (RT) activity, based on the use of bromo-deoxyuridine triphosphate (BrdUTP) and a BrdU binding antibody conjugated to alkaline phosphatase. In addition, we developed a product-enhanced RT assay using RNA of hepatitis A virus as a template. These two assays showed positive RT activity in 90.9 and 81.8% of samples, respectively, from cockles displaying disseminated neoplasia as determined by light microscopy. These results strongly support the hypothesis of retroviral etiology for this pathological condition.
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PMID:Evidence of retroviral etiology for disseminated neoplasia in cockles (Cerastoderma edule). 1709 15

The present article describes the presence of hepatitis C virus (HCV) core protein in relation to HCV antibody in different types of liver diseases caused by hepatitis viral infections. One hundred thirty patients with various types of liver diseases, including those with acute viral hepatitis (n = 50), chronic viral hepatitis (n = 30), cirrhosis of the liver (n = 30), and fulminant hepatic failure (n = 20), were analyzed for HCV core protein, HCV-ribonucleic acid (RNA) and anti-HCV antibodies using enzyme immunoassays and reverse transcriptase-polymerase chain reaction. All patients were also simultaneously analyzed for other hepatitis markers to diagnose hepatitis A to E in all cases. Patients with HCV infection were additionally tested for HCV core protein and HCV-RNA. The results of analysis demonstrated the presence of hepatitis B, C, and E in different proportions of patients with these liver diseases. Hepatitis A and D infections were absent in all cases. Analysis of sera from acute viral hepatitis demonstrated the presence of HCV core protein, HCV-RNA, anti-HCV antibodies, and both core protein and anti-HCV together in 18%, 16%, 6%, and 2% of cases, respectively. In fulminant hepatic failure patients, these markers were recorded in 20%, 10%, 10%, and 5% of cases, respectively. In the chronic viral hepatitis group, the pattern was reversed, and their presence was recorded in 13.3%, 13.3%, 46.6%, and 10% of cases, respectively. Similarly, in cirrhosis patients, these markers were noted in 23.3%, 23.3%, 23.3%, and 13.3% of cases, respectively. None of the control sera were positive for any hepatitis marker. The significance of HCV core protein in relation to HCV-RNA and anti-HCV for the diagnosis of HCV infection in different liver diseases has been discussed.
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PMID:Significance of hepatitis C virus core protein in the diagnosis of hepatitis C virus infection in different liver diseases. 1716 73

Water, salad vegetables and fruits exposed to fecal contamination may cause outbreaks of hepatitis A. A protocol of viral concentration by filtration on electronegative membrane filter and a protocol based on a viral elution in Tris-glycine buffer, pH 9.5 with concentration by polyethylene glycol precipitation were associated with real-time, reverse transcriptase-PCR to detect hepatitis A virus (HAV) artificially inoculated in 2 l of tap water, or on 25 g of fruits or salad vegetables. These methods were characterized by an intra-laboratory study using the international standard ISO 16140 on five types of tap water, six types of fruit and five types of salad vegetable. Linear regression models describing the quantitative reactions were good fits to data, and the variances of results were constant in the whole range of viral concentrations tested, which was from about 1.7 to 5.7 log plaque-forming units (PFU) per 2 l of tap water, from about 2.0 to 4.5 log PFU/25 g of fruits, and from 1.5 to 3.5 log PFU/25 g of salad vegetables. Fractions of inoculated viruses recovered were estimated to be about 20% for tap water, about 16% for salad vegetables, and about 7% for fruits. The probability of detecting positive samples was 50% (the critical level of detection) when 2 l samples of tap water were inoculated with 0.7 log PFU of HAV, 25 g samples of iceberg lettuce were inoculated with 1.0 log PFU of HAV, and 25 g samples of fresh and frozen raspberries were inoculated with 1.0 and 1.5 log PFU of HAV, respectively.
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PMID:Detection and quantification by real-time RT-PCR of hepatitis A virus from inoculated tap waters, salad vegetables, and soft fruits: characterization of the method performances. 1749 Jul 71

Hepatitis E indigenous to developed countries (hepatitis EIDC) is a form of hepatitis E in persons with no travel history to highly endemic areas. It has been recognized recently as an emerging clinical entity in a significant number of economically developed countries including UK. However, it is still perceived as a rare disease and routine laboratory testing for hepatitis E is not performed. A series of 13 cases of hepatitis EIDC, diagnosed in a 13-month period from June 2005 within a single center in South Hampshire, UK, is presented. These patients were identified after implementing a novel-screening algorithm that introduced routine hepatitis E serological investigations. Patients were middle aged or elderly and males were affected more commonly. Four patients (31%) required hospital admission. All reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed cases carried hepatitis E virus (HEV) genotype-3, which bore close sequence homology to HEV circulating in UK pigs. None of these patients recalled eating undercooked pork products or close contact with pigs during the 2 months preceding the onset of acute hepatitis. In comparison, during the same period, only two cases of hepatitis A and five cases of acute hepatitis B were diagnosed. These data illustrate the importance of introducing routine hepatitis E testing in all patients with unexplained acute liver disease and absence of relevant travel history. Routine testing can clarify hepatitis E epidemiology whilst improving the clinical management of patients with acute liver disease.
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PMID:Unexpectedly high incidence of indigenous acute hepatitis E within South Hampshire: time for routine testing? 1809 34

Anti-HAV IgM positive serum samples from acute phase hepatitis A patients from various areas in Turkey were tested for viral RNA by RT-PCR (reverse transcriptase polymerase chain reaction), using primer pairs from two different regions of the HAV genome. The PCR products amplified from both genomic regions underwent phylogenetic analyses. A comparison of the regions showed the same genotyping results, and the RT-PCR-2 in the 5'NCR demonstrated greater sensitivity compared to RT-PCR-1 in the VP1-P2A region. The majority of the isolates belonged to genotype IB and are related closely to each other; however, two isolates related even more strongly to the HAV HM175 strain. Two (n = 37) RT-PCR positive sera were classified under genotype IA. A surprising finding emerged for the mean levels of serum transaminases AST and ALT: higher levels were found in patients under 10 years of age compared to older patients. Anti-HAV IgM levels were determined quantitatively and, in addition, the HAV-RNA genome equivalents were ascertained by real time RT-PCR. No evidence was found for an association between viral load and the higher transaminase levels in the younger group.
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PMID:Acute hepatitis A virus infection in Turkey. 1836 Aug 91

The aim of this study was to assess the presence and seasonal frequency of various enteric viruses in wastewater treatment. The detection of astrovirus, norovirus, enterovirus, hepatitis A virus (HAV) and rotavirus was carried out by molecular analyses in concentrated water samples collected over 18 months at the entrance and exit of an activated sludge sewage treatment plant. The reverse transcriptase-polymerase chain reaction (RT-PCR) results were confirmed by sequencing, and comparative phylogenetic analysis was performed on the isolated strains. Genomes of human astrovirus and human rotavirus were identified in 26/29 and 11/29 samples of raw sewage, respectively, and in 12/29 and 13/29 treated effluent samples, respectively. Some rotavirus sequences detected in environmental samples were very close to those of clinical strains. Noroviruses, enteroviruses and HAV were not detected during the study period. This could be related to the small sample volume, to the sensitivity of the detection methods or to local epidemiological situations. Frequent detection of viral RNA, whether infectious or not, in the exit effluent of sewage treatment indicates wide dispersion of enteric viruses in the environment. Consequently, viral contamination resulting from the use of these treated waters is a risk that needs to be addressed.
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PMID:An epidemiological study of enteric viruses in sewage with molecular characterization by RT-PCR and sequence analysis. 1910 55

Polymerase chain reaction (PCR)-based approaches to the detection, differentiation and characterization of avian pathogens continue to be developed and refined. The PCRs, or reverse transcriptase-PCRs, may be general, designed to detect all or most variants of a pathogen, or to be serotype, genotype or pathotype specific. Progress is being made with respect to making nucleic acid approaches more suitable for use in diagnostic laboratories. Robotic workstations are now available for extraction of nucleic acid from many samples in a short time, for routine diagnosis. Following general PCR, the DNA products are commonly analyzed by restriction endonuclease mapping (restriction fragment length polymorphism), using a small number of restriction endonucleases, based on a large body of sequence data. Increasingly, however, nucleotide sequencing is being used to analyze the DNA product, in part due to the expanding use of non-radioactive sequencing methods that are safe and enable high throughout. In this review, I highlight some recent developments with many avian viruses: Newcastle disease virus; circoviruses in canary and pigeon; infectious bursal disease virus (Gumboro disease virus); avian adenoviruses, including Angara disease/infectious hydropericardium virus, haemorrhagic enteritis virus of turkeys, and egg drop syndrome virus; avian herpesviruses, including infectious laryngotracheitis virus, duck plague virus, psittacine herpesvirus (Pacheco's parrot disease virus), Marek's disease virus and herpesvirus of turkeys; avian leukosis virus (associated with lymphoid leukosis or myeloid leukosis, and egg transmission); avian pneumoviruses (turkey rhinotracheitis virus); avian coronaviruses, including infectious bronchitis virus, turkey coronavirus and pheasant coronavirus; astrovirus, in the context of poult enteritis and mortality syndrome, and avian nephritis virus; and avian encephalomyelitis virus, a picornavirus related to hepatitis A virus.
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PMID:Innovation and discovery: the application of nucleic acid-based technology to avian virus detection and characterization. 1918 52

Hepatitis A virus (HAV) infection is the leading worldwide cause of acute viral hepatitis. An important aspect of viral control is rapid diagnosis. Epidemiological studies have linked hepatitis A outbreaks to the consumption of drinking water or soft fruits exposed to faecal contamination. Real-time reverse transcriptase PCR (qRT-PCR) is now widely used for detecting RNA viruses in food samples. Efficiency of viral concentration, nucleic acid extraction and the presence of potential inhibitors of the RT-PCR reaction must be monitored to prevent false negative results. In this study, the MS2 bacteriophage used as a process control was detected simultaneously with HAV in a one-step duplex real-time qRT-PCR. The assay was developed for testing water and raspberries. Adding MS2 showed no loss of sensitivity for HAV detection in water and raspberry samples. The limit of detection of HAV with this new approach was 10PFU for 1.5L of bottled water, 100PFU for 1.5L of tap water, 50PFU for 25g of fresh raspberries and 100PFU for 25g of frozen raspberries. The data show that the MS2 offers a very reliable and simple way to monitor false-negative results, making it a valuable tool in the routine diagnostics laboratory.
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PMID:Duplex real-time qRT-PCR for the detection of hepatitis A virus in water and raspberries using the MS2 bacteriophage as a process control. 2018 60

RNA extraction from environmental samples yields frequently an RNA preparation containing inhibitors of molecular reactions. Commercial RNA extraction kits commonly permit extraction of only 0.1-0.2 ml sample volume. An RNA extraction buffer (RNAX buffer) was formulated for the extraction of viral RNA from 4.0 ml using a silica column based protocol. To evaluate the RNAX buffer based protocol, we used hepatitis A virus (HAV) and coxsackievirus B3 (CVB3) to monitor the RNA extraction efficiency from environmental samples. For evaluation of viral RNA recovery from water concentrates which were prepared from river and pond water by PEG concentration, serial ten fold dilutions of two waterborne viruses were added to the water concentrates for evaluation by quantitative detection. Quantitative recovery of HAV and CVB3 was determined by reverse transcriptase quantitative real-time PCR (RT-qPCR). The extracted RNA was compatible with RT-qPCR and sensitivity of detection of 0.8PFU per reaction was found with RNAX buffer and the developed protocol. This level of sensitivity was obtained using viral RNA extracted from 4.0 ml of an inoculated water sample concentrate. The RNAX buffer developed in this study could be applicable to the detection of other pathogens in water and food.
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PMID:Development of an RNA extraction protocol for detection of waterborne viruses by reverse transcriptase quantitative PCR (RT-qPCR). 2060 Mar 32

Foodborne outbreaks caused by noroviruses (NoVs) and hepatitis A virus (HAV) are often linked to consumption of contaminated shellfish. The objective of this study was to identify an appropriate virus recovery method for real-time reverse transcriptase (RT)-PCR detection and subsequently to evaluate this method on shellfish bioaccumulated with virus in a collaborative study. Five methods were compared for recovery of NoV GII.7 and feline calicivirus from spiked digestive tissue of oysters and mussels. A method based on proteinase K digestion followed by NucliSENS miniMAG extraction was found to be the most efficient with a 50% limit of detection (LOD(50)) of 62 and 12 RT-PCR U/1.5 g digestive tissue for NoV GII.7 in oysters and mussels, respectively. Evaluation of the method in four laboratories found the percentage of sensitivity, based on low/high levels of virus bioaccumulated in oysters, to be 33/80 for NoV GI.3b, 13/92 for NoV GII.4 and 50/42 for HAV. A specificity of 100% was found for all three viruses in non-bioaccumulated oysters. As process control Mengovirus (vMC(0)) showed an average recovery of 1.8% from oysters and 1.2% from mussels. The study demonstrates that this recovery method can be useful for harmonized data generation and routine viral analyses of shellfish.
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PMID:Evaluation of a rapid method for recovery of norovirus and hepatitis A virus from oysters and blue mussels. 2060 52


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