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Biomedical subjects

B Maurer

Publications and source records attributed to B Maurer.

At least 37 records · Page 2Linked to original sources

Infectious DNA of the human spumaretrovirus.

An infectious molecular clone (pHSRV) of the human Spumaretrovirus (HSRV) was constructed using viral DNA and cDNA clones. The infectivity of pHSRV was proven by transfection of cell cultures and subsequent infection of susceptible cultures with cell free transfection derived virus. pHSRV derived virus produced foamy virus typical cytopathic effects in susceptible cultures. Infected cells could be stained specifically with foamy virus antisera by means of indirect immunofluorescence. Radioimmunoprecipitation revealed the presence of characteristic HSRV structural proteins in pHSRV infected cultures. By cotransfection of pHSRV and an indicator plasmid it was found that pHSRV is able to transactivate the viral LTR. Viral transcripts were found to be approximately 200 bases longer in pHSRV infected cultures compared to wildtype infected cultures. This difference is most likely due to an insertion of DNA of non-viral origin in the U3 region of the 3'LTR of the infectious clone.

Animals↗

Transacting transcriptional activation of human spumaretrovirus LTR in infected cells.

The long terminal repeat (LTR) of the human spumaretrovirus (HSRV) was examined with respect to its ability to function as transcriptional promotor in virus-infected and uninfected cells. Transient transfections using a plasmid in which the 3' LTR of HSRV was coupled to the bacterial chloramphenicol acetyltransferase (cat) gene revealed that the level of HSRV LTR-directed cat gene expression was markedly increased in HSRV-infected cells compared to uninfected cells. Northern blot analysis of cat mRNA from transfected cultures suggests that transactivation of HSRV-directed gene expression occurs at the transcriptional level.

Animals↗

Identification of the major immunogenic structural proteins of human foamy virus.

We have identified the major immunogenic structural proteins of the human foamy virus (HFV), a distinct member of the foamy virus subfamily of Retroviridae. Radiolabelled viral proteins were immunoprecipitated from HFV-infected cells by foamy virus antisera of human and non-human primate origin. Precipitated viral proteins were in the range of 31K to 170K. Labelling of proteins with [14C]glucosamine or with [35S]methionine in the presence of tunicamycin, as well as endo-beta-N-acetylglycosaminidase H and F treatment of [35S]methionine-labelled proteins, revealed three viral glycoproteins of approximately 170K, 130K and 47K, most likely representing the env gene-encoded precursor, the surface glycoprotein and the transmembrane protein of HFV, respectively.

Antigens, Viral↗

Staphylococcus aureus septicaemia: the initial presentation of polyarteritis nodosa.

A 51-year-old man presented with Staphylococcus aureus septicaemia. He improved initially but died suddenly on day 8 of his hospital admission. Post-mortem examination revealed multiple lesions of polyarteritis nodosa which were the cause of death. We are unaware of any other case of polyarteritis nodosa that presented with Staphylococcus aureus septicaemia. These two conditions have a number of similar clinical characteristics and are difficult to distinguish unless the association is considered.

Diagnosis, Differential↗

Genomic organization of the human spumaretrovirus and its relatedness to AIDS and other retroviruses.

The human spumaretrovirus (HSRV) isolated from a nasopharynx carcinoma patient 17 years ago has a RNA genome 11 kb in size. It encodes besides the gag, pol, and env genes several novel genes (S1 and bel 1, 2, and 3) that are comparable to the regulatory genes R, X, tat, art, and 3'-orf of the human (HIVs) and simian immunodeficiency viruses (SIVs) with respect to genomic location and to sizes of the putative gene products. A comparison between the HIV protein sequences of the pol and the novel genes to the corresponding gene product sequences of HSRV revealed that HSRV is related to the lentiviruses but occupies a distinct phylogenetic placement of its own. A detailed analysis of the reverse transcriptase domain allows the construction of a phylogenetic tree for the known retroviral subfamilies and/or groups, including the oncoviruses, the lentiviruses, the spumaviruses, the HLTV-BLV group, and the D-type viruses. Regions of the putative novel HSRV gene products with segmental protein sequence homology to the regulatory protein of other human retroviruses are discussed. The results strengthen the view that HSRV and its novel genes should be studied in comparison to the new genes of acquired immunodeficiency syndrome (AIDS) viruses and human T cell leukemia viruses (HTLV).

Chromosome Mapping↗

Analysis of the primary structure of the long terminal repeat and the gag and pol genes of the human spumaretrovirus.

The nucleotide sequence of the human spumaretrovirus (HSRV) genome was determined. The 5' long terminal repeat region was analyzed by strong stop cDNA synthesis and S1 nuclease mapping. The length of the RU5 region was determined and found to be 346 nucleotides long. The 5' long terminal repeat is 1,123 base pairs long and is bound by an 18-base-pair primer-binding site complementary to the 3' end of mammalian lysine-1,2-specific tRNA. Open reading frames for gag and pol genes were identified. Surprisingly, the HSRV gag protein does not contain the cysteine motif of the nucleic acid-binding proteins found in and typical of all other retroviral gag proteins; instead the HSRV gag gene encodes a strongly basic protein reminiscent of those of hepatitis B virus and retrotransposons. The carboxy-terminal part of the HSRV gag gene products encodes a protease domain. The pol gene overlaps the gag gene and is postulated to be synthesized as a gag/pol precursor via translational frameshifting analogous to that of Rous sarcoma virus, with 7 nucleotides immediately upstream of the termination codons of gag conserved between the two viral genomes. The HSRV pol gene is 2,730 nucleotides long, and its deduced protein sequence is readily subdivided into three well-conserved domains, the reverse transcriptase, the RNase H, and the integrase. Although the degree of homology of the HSRV reverse transcriptase domain is highest to that of murine leukemia virus, the HSRV genomic organization is more similar to that of human and simian immunodeficiency viruses. The data justify classifying the spumaretroviruses as a third subfamily of Retroviridae.

Amino Acid Sequence↗

The 3'-orf protein of human immunodeficiency virus 2 shows sequence homology with the bel3 gene of the human spumaretrovirus.

The primary amino acid sequence within a domain of 89 residues of the central part of the 3'-orf protein (p27 3'-orf) of human immunodeficiency virus (HIV-2) shares homology with the middle and carboxy-terminal portion of the bel3 gene product of human spumaretrovirus (HSRV). In addition, a limited region of the tat protein of HIV-2 but not HIV-1 shows a 28% degree of homology to the deduced protein sequence of the bel1 gene product of HSRV. Comparison between the viral sequences suggests that the 3'-orf and bel1 gene product of HSRV could serve similar functions to those in HIV-2.

Amino Acid Sequence↗

Nucleotide sequence analysis of the env gene and its flanking regions of the human spumaretrovirus reveals two novel genes.

Recombinant clones that represent the 3' part of the genome of the human spumaretrovirus (foamy virus) were established from viral DNA and from DNA complementary to viral RNA. The recombinant clones were characterized by blot hybridizations and nucleotide sequence analysis. The deduced protein sequence of the clones at their 5' ends was found to be homologous to the 3' domain of retroviral reverse transcriptases. Downstream of a small intergenic pol-env region a long open reading frame of 985 amino acid residues was identified that according to its genomic location, size, glycosylation signals, and hydrophobicity profile closely resembles the lentiviral env genes. The spumaretroviral env gene is followed by two open reading frames, termed bel-1 and bel-2 which are located between env and the long terminal repeat region. The long terminal repeat of 1259 nucleotides is preceded by a polypurine tract and contains the canonical signal sequences characteristic for transcriptional regulation of retroviruses. The provisional classification of the spumaretrovirus subfamily is discussed.

Amino Acid Sequence↗

Molecular cloning of the genome of human spumaretrovirus.

DNA of human spumaretrovirus (HSRV) was cloned from both cDNA and from viral DNA into phage lambda and bacterial plasmid vectors. The recombinant plasmids harboring viral DNA were characterized by Southern blot hybridization and restriction mapping. Physical maps were constructed from cDNA and found to be colinear with the restriction maps obtained from viral DNA. The recombinant clones isolated contained viral DNA inserts which range in size from 2.2 kb to 15.4 kb. The recombinant clones allowed to construct a physical map of the complete HSRV provirus of 12.2 kb.

Cloning, Molecular↗

Nucleotide sequence analysis of a cloned DNA fragment from human cells reveals homology to retrotransposons.

During molecular cloning of proviral DNA of human spumaretrovirus, various recombinant clones were established and analyzed. Blot hybridization revealed that one of the recombinant plasmids had the characteristic features of a member of the long interspersed repetitive sequences family. The DNA element was analyzed by restriction mapping and nucleotide sequencing. It showed a high degree of amino acid sequence homology of 54.3% when compared with the 5'-terminal part of the pol gene product of the murine retrotransposon LIMd. The 3' region of the cloned DNA element encodes proteins with an even higher degree of homology of 67.4% in comparison to the corresponding parts of a member of the primate KpnI sequence family.

Amino Acid Sequence↗

[Differential arthrographic diagnosis of the painful shoulder joint].

60 arthrograms of the shoulder were explored under morphologic and pathologic-anatomic aspects. Differentiation was made between acute and chronic pain. The possible findings in leaking of the contrast material out of the joint capsule are shown and discussed. Signs are quoted of degeneration of soft tissue and bone. The findings in patients with rheumatoid arthritis and a history of shoulder dislocation are summarised. Distension of the joint capsule without shoulder dislocation is described. Filling of the periarticular lymphatics is mentioned in different cases.

Adolescent↗

Bi-atrial myxomas presenting as recurrent pulmonary emboli in a girl.

A 14-year-old girl whose sole presenting features were symptoms of pulmonary embolism, was found to have bi-atrial myxomas. The diagnosis was made preoperatively, and the patient had a successful outcome following elective surgery. The absence of other features such as systemic embolism, atrioventricular valvular obstruction, fever and constitutional symptoms makes this a most unusual case. Right atrial myxoma should be considered in any patient presenting with pulmonary embolism for which there is no obvious source.

Adolescent↗