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Biomedical subjects

M Maaronen

Publications and source records attributed to M Maaronen.

4 recordsLinked to original sources

Pathogenetic differences between coxsackie A and B virus infections in newborn mice.

Coxsackieviruses are divided into A and B subgroups on the basis of their pathogenicity in newborn mice. Although used in the classification of these viruses, our understanding of the details of the infection is incomplete due to the lack of sensitive and specific techniques to localize the viruses in affected tissue. We have used in situ hybridization to detect coxsackievirus genomes in tissues of newborn mice after infection by five serotypes (A2, A9, A21, B3 and B4) through different administration routes. Our results indicate that coxsackie A viruses are able to affect both skeletal and heart muscle while the coxsackievirus B subgroup infects a wide range of tissues. In addition to striated muscle these include central nervous system, liver, exocrine pancreas and brown fat. This model will make it possible to analyze molecular factors determining tissue tropism.

Animals

A distinct picornavirus group identified by sequence analysis.

Although echovirus 22 is presently classified as a member of the enterovirus group in the family of picornaviruses, it has been reported to have exceptional biological properties when compared with other representatives of the group. We have determined the complete nucleotide sequence of the echovirus 22 (Harris strain) genome, which appears to be significantly different from all the other studied picornaviruses. However, the organization of the genome [7339 nucleotides, excluding the poly(A) tract] is similar to that of previously sequenced picornaviruses. This genome includes a 5' untranslated region, relatively well-conserved when compared with aphtho- and cardioviruses, followed by an open reading frame coding for a 2180-amino acid-long polyprotein. The amino termini of capsid polypeptides VP1 and VP3 were determined by direct sequencing, and the other proteolytic cleavage sites in the polyprotein were predicted by comparison with other picornavirus proteins. The amino acid identities of echovirus 22 polypeptides with the corresponding proteins of other picornaviruses are in the 14-35% range, similar to those percentages seen when representatives of the five picornavirus groups (entero-, rhino-, cardio-, aphtho-, and hepatoviruses) are compared. Our results suggest that echovirus 22 belongs to an independent group of picornaviruses.

Amino Acid Sequence

Polymerase chain reaction for human picornaviruses.

We have used enzymic amplification of specific nucleic acid sequences followed by hybridization, for the rapid detection and typing of human picornaviruses after cell culture isolation. The test is based on the synthesis of cDNA, the polymerase chain reaction and the use of oligonucleotide probes. The primers were selected from the 5' non-coding region of the genome representing highly conserved regions. Sequences specific to enteroviruses and rhinoviruses were used as probes. The assay was able to identify all the picornavirus reference strains analysed and it was also possible to discriminate between enteroviruses and rhinoviruses by the hybridization procedure. When 29 picornavirus clinical isolates were analysed, all except one were detected by gel electrophoresis and a specific hybridization signal was obtained with all except three strains using the oligonucleotide probes.

Base Sequence

Nucleic acid sequence relationships between enterovirus serotypes.

Forty-eight different enterovirus serotypes were analysed by a nucleic-acid hybridization test using probes derived from the 3' end of coxsackievirus A21 (CA21) and B3 (CB3), poliovirus 3 (P3) and enterovirus 70 (E70). More than 90% of the serotypes could be detected with this collection of reagents. The CB3 probe reacted with all the coxsackie B viruses, with all three poliovirus serotypes, and with almost all of the 30 ECHO virus types tested. In addition some of the coxsackie A viruses and the BrDr 73 strain of enterovirus 71 gave a positive signal with this probe. The P3 probe detected all the poliovirus strains and also some coxsackievirus A isolates but no coxsackie B or ECHO viruses. A similar hybridization pattern as with the P3 probe was obtained when the CA 21 probe was used. The E70 probe appeared to be strain-specific. The results indicate that nucleic-acid hybridization is a useful method for rapid detection and subgrouping of enteroviruses during virus isolation, and that the test could be further developed for typing of the strains.

Animals