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At least 577 records · Page 32Linked to original sources
PubMed1993

Differentiation of species of the genus Orthopoxvirus in a dot blot assay using digoxigenin-labeled DNA-probes.

A dot blot assay using five different digoxigenin-labeled probes was established for specific detection and differentiation of four species belonging to the genus Orthopoxvirus. As little as 20 pg orthopoxvirus DNA can be detected, corresponding to approximately 8 x 10(4) DNA molecules. A total of 37 orthopoxvirus strains and isolates of different origin were investigated and could be assigned to the species vaccinia, cowpox, camelpox, and mousepox virus. These findings agree with their identification by biological means. Additionally, a simple procedure to isolate orthopoxvirus DNA directly from scab material was developed. This allows a fast classification without isolating the virus.

Animals↗
PubMed2001

[The examinations associating with hepatitis C virus and medical reimbursement].

The number of persons infected with hepatitis C virus(HCV) is estimated to be about one to two million in Japan. Recently researchers have shown a growing interest in HCV, since the virus infection may cause liver cirrhosis and hepatocellular carcinoma. The examinations for HCV can be divided into host factor and virus factor detection methods. Classification and cost of HCV tests are shown. Antibody tests as host factor detection are used to screen for infection, for auxiliary diagnosis of viremia and for choosing treatment. Virus factor tests, such as the measurement of the viral load can be used for choosing treatment and determining the response to therapy. We describe that usage of laboratory tests for HCV and discuss medical insurance coverage.

Hepatitis C↗
PubMed2004

Sample size calculations for Bayesian prediction of bovine viral-diarrhoea-virus infection in beef herds.

We used a Bayesian classification approach to predict the bovine viral-diarrhoea-virus infection status of a herd when the prevalence of persistently infected animals in such herds is very small (e.g. <1%). An example of the approach is presented using data on beef herds in Wyoming, USA. The approach uses past covariate information (serum-neutralization titres collected on animals in 16 herds) within a predictive model for classification of a future observable herd. Simulations to estimate misclassification probabilities for different misclassification costs and prevalences of infected herds can be used as a guide to the sample size needed for classification of a future herd.

Animals↗
PubMed1995

Evaluation of a reverse hybridization assay for genotyping of hepatitis C virus.

BACKGROUND/AIMS: Several strains of the hepatitis C virus exist; distinct genotypes and subtypes can be identified by sequence comparison of the viral genomes. Recent evidence that the genotype/subtype of hepatitis C virus may influence the clinical course of chronic hepatitis C and the response to interferon-alpha therapy for this disease suggests that methods to identify the genotype may become clinically useful. In the present study we evaluated a recently introduced reverse hybridization assay. METHODS: HCV-RNA was isolated from serum samples from 61 consecutive patients attending our out-patient clinic and subsequently sequenced in the 5'-noncoding and the nonstructural-5 region by the dideoxynucleotide chain termination method. HCV-genotyping was performed by phylogenetic analysis of nonstructural-5 sequences. The amplification product for the reverse hybridization assay was obtained by "nested" polymerase chain reaction using biotinylated primers corresponding to the 5'-noncoding region. The assay is based on hybridization of the resulting polymerase chain reaction product with oligonucleotide probes immobilized as parallel lines on membrane strips. RESULTS: According to the phylogenetic analysis of the nonstructural-5 region the prevalence of hepatitis C virus subtypes was as follows: 1a 18%, 1b 51%, 2a 3%, 2b 3%, 2c 7% and 3a 18%. The reverse hybridization assay correctly identified each hepatitis C virus genotype (1, 2, and 3). However, differentiation of hepatitis C virus subtypes was insufficient. 1/11 HCV-1a isolates was incorrectly classified by the reverse hybridization assay as HCV-1b and vice versa 3/31 HCV-1b isolates as HCV-1a. Classification of hepatitis C virus subtypes 2a, 2b and 3a was correct, but 4/4 HCV-2c isolates were misinterpreted by the assay as HCV-2a. CONCLUSIONS: The reverse hybridization assay can differentiate between hepatitis C virus genotypes 1, 2, and 3, but is not completely reliable for hepatitis C virus subtyping.

Base Sequence↗
PubMed1990

[Primates in the study of hepatitis viruses].

There is no a conventional tissue culture system for the propagation of the hepatitis viruses and only some of them can be maintain in continuous cell culture in particular conditions. A transmissibility of hepatitis is limited to primates. The narrow host specificity may help to establish the classification of the hepatitis viruses and their mode of transmission. Moreover, the primate animal model provided the most accessible source of viruses and for clinical reasons presents the only opportunity for the studies of pathogenic mechanisms involving cellular immunity with allogenic restriction. The marmosets and chimpanzees susceptible to the hepatitis A and B viruses, respectively are the primates of choice for the experimental models. For the studies on parenterally transmitted NANB hepatitis the chimpanzee and some rhesus monkeys may provide an animal system. At last, most of the primates seem to be susceptible to agent responsible for the water-borne non A non B hepatitis.

Animals↗
PubMed1994

[Immunological study of Japanese encephalitis virus--characterization of monoclonal antibodies against Muar and 691004 strains].

Based on our previous study using monoclonal antibodies against three Japanese encephalitis (JE) virus strains, Nakayama-RFVL, Beijing 1 and Kamiyama, twenty-five JE virus strains isolated between 1935 and 1979 were classified into four or five serotypes. In the present study, monoclonal antibodies against Muar and 691004 strains which showed different reactivities from the three above strains were produced to analyze immunological characteristics of JE virus in detail and identify isolated viruses accurately. The ten anti-Muar (MUAMA 1-10) and the fourteen anti-691004 (69-MA 1-14) monoclonal antibodies which reacted specifically with the JE virus by the hemagglutination inhibition (HI) test were obtained. In order to clarify the immunological characteristics of MUAMAs and 69-MAs, the HI reactivity of each was tested against the twenty-five JE virus strains. Of the ten MUAMAs, one strain-specific (MUAMA 1), two intermediately reactive and seven JE species-specific antibodies were recognized, but 691004 strain-specific antibody was not obtained. The serological classification of 25 JE virus strains using MUAMAs and 69-MAs basically corresponded with our previous results. However, 691004 strain would be classified into a subtype of Nakayama serotype according to the reactive pattern. Consequently, the 25 JE virus strains all fell into four serotypes: Nakayama, Beijing 1, Kamiyama and Muar. All twenty-four monoclonal antibodies produced in this study showed neutralization activities and belonged to the IgM class, kappa type.

Animals↗
PubMed1994

Isolation and classification of temperature-sensitive mutants of influenza B virus.

We isolated 25 temperature-sensitive mutants of B/Kanagawa/73 strain generated by mutagenesis with 5-fluorouracil and classified them into seven recombination groups by pair-wise crosses. All mutants showed a ratio of plaquing efficiency at the nonpermissive temperature (37.5 C) to the permissive temperature (32 C) of 10(-4) or less. At 37.5 C most of group I, II, and III mutants did not produce appreciable amounts of protein, but all other group mutants were protein synthesis-positive. A group VII mutant produced active hemagglutinin (HA) and neuraminidase (NA) at the nonpermissive temperature, but Group V mutants produced only active NA and were defective in the HA molecule. The other group mutants, including group IV mutants with mutation only in the NA gene (8, 10), lacked both activities at the nonpermissive temperature. One of nine influenza B virus isolates in 1989 had EOP 37.5/32 of 1/3 x 10(-2) and belonged to recombination group VII.

Animals↗
PubMed1978

Classification of the New Jersey serotype of vesicular stomatitis virus into two subtypes.

We propose a reclassification of five strains of the New Jersey serotype of vesicular stomatitis virus into two subtypes designated Concan and Hazelhurst. This subclassification into two subtypes is based on reciprocal differences in antibody neutralization of virion infectivity, nucleotide base sequence homology, oligonucleotide maps of virion RNA, and interference by defective-interfering particles.

Base Sequence↗
PubMed2006

Overview on chronic viral cardiomyopathy/chronic myocarditis.

Myocarditis is most often induced by cardiotropic viruses and often resolves with minimal cardiac remodelling and without discernable prognostic impact. Acute myocarditis has a highly diverse clinical presentation (asymptomatic, infarct-like presentation, atrioventricular (AV)-block, atrial fibrillation, sudden death due to ventricular tachycardia, fulminant myocarditis with severely depressed contractility). Progression of myocarditis to its sequela, dilated cardiomyopathy (DCM), has been documented in 20% of cases and is pathogenically linked to chronic inflammation and viral persistence. Persistence of cardiotropic viruses (enterovirus, adenovirus) constitutes one of the predominant aetiological factors in DCM. Additionally, circulating autoantibodies to distinct cardiac autoantigens have been described in patients with DCM, providing evidence for autoimmune involvement. Since clinical complaints of myocarditis and DCM are unspecific, a positive effect of any specific therapy depends on an accurate biopsy-based diagnosis and characterization of the patients with histological, immunohistological and molecular biological methods (PCR), which have developed into sensitive tools for the detection of different viruses, active viral replication, and myocardial inflammation. The immunohistochemical characterization of infiltrates has supported a new era in the diagnosis of myocardial inflammation compared with the Dallas criteria, which has led to a new entity of secondary cardiomyopathies acknowledged by the WHO, the inflammatory cardiomyopathies (DCMi). Immunohistochemically quantified lymphocytes significantly better reflect troponin levels and correlate with findings by anti-myosin scintigraphy compared with the histological analysis. Furthermore, the orchestrated induction of endothelial cell adhesion molecules (CAMs) in 65% of DCM patients has confirmed that CAM induction is a prerequisite for lymphocytic infiltration in DCMi. The combination of these immunohistological with molecular biological diagnostic techniques of virus analysis allows a further classification of dilated cardiomyopathy by differentiating the disease entity in subgroups of virus-positive and virus-negative patients with or without cardiac inflammation. Further analysis of the predominant Th1-/Th2-immune response may provide additional prognostic information on the natural course of the disease. This differential analysis improves the clinical management of patients and is an indispensable prerequisite for the development of specific antiviral or immunomodulatory treatment strategies.

Cardiomyopathies↗
PubMed2000

Single genotype of measles virus is dominant whereas several genotypes of mumps virus are co-circulating.

We have reported that in Japan measles virus strains have been classified into three distinct different genotypes (C1, D3 and D5) under the new international genotype classification since 1984. Similarly, mumps virus strains have been divided into two genotypes with three subtypes (B1, B2, B3, and D) under the proposed international classification since 1976. To differentiate these genotypes we developed a restriction fragment length polymorphism assay in the hemagglutinin (H) region for measles virus and in the hemagglutinin-neuraminidase (HN) region for mumps virus to facilitate the expanded molecular epidemiology. In the Sapporo 1995/1996 measles outbreak, all 26 strains were classified as D5. Among 32 samples from patients with measles from 1994 to 1997 in Tokyo, 28 were identified as D5 and four were D3; these D3 strains were ascertained as a same hospital acquired infection. Among 45 strains obtained in the Tokyo 1999 outbreak, 38 were D3 and the remaining seven were D5. The dominant genotype of measles in Tokyo has replaced from D5 to D3 similar to the Chicago1/89 strain. We obtained 220 samples from patients with mumps from 1993 to 1997 and they were classified into one strain of B1, 14 strains of B2, 151 strains of B3, and 54 strains of D. Therefore, we suggest that two or three subtypes of mumps virus are co-circulating with a different geographic pattern in genotype distribution, whereas a single measles virus genotype is dominantly observed, showing different epidemiological patterns.

Amino Acid Sequence↗
PubMed1996

Human recombinant antibody fragments neutralizing human immunodeficiency virus type 1 reverse transcriptase provide an experimental basis for the structural classification of the DNA polymerase family.

We describe in this paper the binding and biochemical properties of two human antibody fragments directed against the human immunodeficiency virus type 1 reverse transcriptase (RT). These fragments were isolated from a synthetic combinatorial library of human Fab antibody fragments displayed on the surface of filamentous phage. The antibody fragments were selected by using recombinant heterodimeric human immunodeficiency virus type 1 RT purified from insect cells as a solid-phase selector. This procedure led to the isolation of two antibody fragments that completely neutralize the RNA-dependent DNA polymerase activity of RT at nanomolar concentrations. Both antibody fragments bind only to the enzymatically active form of the RT. The inhibitory activity of the anti-RT antibody fragments is competitive with respect to the template primer. The antibody fragments also neutralize the activities of RTs from avian and murine retroviruses and of DNA polymerases of prokaryotic origin as well as human DNA polymerase alpha. Thus, the antibody fragments selected and characterized in this study appear to recognize a structural fold that is common to the different DNA polymerases and necessary for their activity. The results provide an immunological experimental basis for a purely structural and evolutionary classification of the polymerase family.

Animals↗
PubMedDate not supplied

Identification of mosquito-borne flavivirus sequences using universal primers and reverse transcription/polymerase chain reaction.

A reverse transcription/polymerase chain reaction (RT/PCR) protocol for the rapid detection and identification of flaviviruses was developed using a set of universal oligonucleotide primers. These primers correspond to sequences in the 3' non-coding region and in the NS5 gene which are highly conserved among the mosquito-borne flaviviruses. The sequences of the resulting amplified products were analysed for dengue 1, dengue 2, dengue 3, dengue 4, Japanese encephalitis, West Nile, yellow fever and Zika viruses, and compared with the published sequences of other flaviviruses. The 291-297 nucleotides corresponding to the C-terminus of NS5 gene showed 56 to 76% similarity, whereas the 3' non-coding region (190 to 421 nucleotides) showed only 20 to 36% similarity. Genetic classification of the Zika virus supported its traditional serological grouping. Recombinant plasmids containing the flavivirus sequences were used in a nucleic acid hybridization test to identify the RT/PCR products derived from viral RNA extracted from experimentally infected mosquitoes. The plasmids were dotted on a strip of nitrocellulose membrane and incubated with the RT/PCR product labelled with digoxigenin during the PCR step. This is a valuable method for the rapid and specific identification of mosquito-borne flaviviruses in biological specimens and for subsequent sequence analysis.

Animals↗
PubMed1978

[Rotavirus as a causative agent of infantile gastroenteritis. Diagnosis and epidemiology (author's transl)].

Some years ago it was not possible in spite of intensive bacteriological and virological work on the etiology of acute infantile gastroenteritis to find any agent that may readily be linked to this disease. Since five years now early sporadic reports about virus-like particles have proved worldwide to be correct and in the meantime have substantially been supported by new findings in that these particles are the main causative agent of infantile gastroenteritis. As part of our electron-microscopic studies some morphological characteristics are shown. The physico-chemical as well as structural properties of the new virus apparently justify its classification into the family of the reoviruses. Rotavirus positive stool specimens were found in 46% of the material sent in by paediatric clinics.

Child↗
PubMed1998

[Appllcation of PYGC and the hierarchical clustering analysis to recognization of viruses].

The pyrolysis gas chromatography of 29 strains nuclear polyhedrosis viruses, 11 strains cytoplasmic polyhedrosis viruses and 16 strains granulosis viruses were performed on a shimadzu GV-9A capillary gas chromatography equipped with a pyrolyser model PYR-2A. The differences among the inclusion bodies of NPV, CPV and GV could clearly be distinguished and also beidentified through analysis of fingerprinting the hierarchical clustering analysis of GC, This procedure has provided a usefel method for the classification and identification of viruses.

Algorithms↗
PubMed1974

Serological characterization of the three major proteins of vesicular stomatitis virus.

The three major proteins of vesicular stomatitis virus-Indiana, glycoprotein (G), nucleoprotein (N), and membrane protein (M), were isolated and characterized by means of specific monocomponent antisera. G, N, and M proteins are distinct, nonrelated antigens with specific serological properties. The G protein is the only antigen inducing the formation of virus-neutralizing antibodies and was shown to confer immunity to mice. Specific complement-fixing and precipitating activity was demonstrated for each of the three antisera. The future use of isolated rhabdovirus components and of monospecific antisera is considered for therapeutic and diagnostic purposes as well as for virus strain differentiation and classification work.

Animals↗