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Biomedical subjects

A Bosch

Publications and source records attributed to A Bosch.

At least 73 records · Page 4Linked to original sources
PubMed1995

Retroviral properties inherent to viral erythrocytic infection in sea bass.

The characterization of the aetiological agent of viral erythrocytic infection (VEI) of sea bass suggests a retroviral origin of the disease. RNA from viral erythrocytic infection virus (VEIV) and DNA from blood and organs of VEI-affected fish hybridized to a specific retrovirus cDNA probe. Sequences homologous to retrovirus genome were also detected in non-infected SBL cells (a sea bass cell line), however, Southern blot analysis showed that the DNA restriction patterns in VEI-affected erythrocytes differed from those of SBL cells. RNA-dependent DNA polymerase activity was detected in VEI-affected sea bass blood. This reverse transcription was strongly Mn(2+)-dependent and is the first report of its occurrence in a marine fish and in fish blood samples. Nucleic acid sequences homologous to retrovirus RNA were detected in chromatographic fractions exhibiting reverse transcriptase activity and the presence of virus-like particles, 125-150 mm in diameter. The density of VEIV in sucrose was 1.17-1.18 g/cm3. The symptomatology of VEI is not far from those described for some retroviral diseases.

Animals↗
PubMed1995

A new human gene from the Down syndrome critical region encodes a proline-rich protein highly expressed in fetal brain and heart.

Down syndrome is a major cause of mental retardation and congenital heart defects. While most of the affected individuals have three copies of chromosome 21, patients with partial trisomy 21 have also been described. These rare cases define a minimal region for the Down syndrome phenotype encompassing about 3 Mb around D21S55. By using a new method for the identification of coding sequences (Alu-splice PCR) we have identified a new gene, DSCR1, from region 21q22.1-q22.2. DSCR1 encodes a novel protein which has an acidic domain, a serine-proline motif, a putative DNA binding domain and a proline-rich region with the characteristics of a SH3 domain ligand. These features suggest that DSCR1 could be involved in transcriptional regulation and/or signal transduction. DSCR1 is highly expressed in human brain and heart, and increased expression in the brains of young rats compared with adults suggests a role for DSCR1 during central nervous system development. Structural characteristics, together with its particular expression in brain and heart, encourage us to suggest that the overexpression of DSCR1 may be involved in the pathogenesis of Down syndrome, in particular mental retardation and/or cardiac defects.

Aging↗
PubMed1995

Anti-hepatitis A virus antibody response elicited in mice by different forms of a synthetic VP1 peptide.

Peptide VP1 (11-25) of the capsid of hepatitis A virus was synthesized by the Fmoc-polyamide solid phase method, and administered to mice in different forms: (1) free, (2) encapsulated in multilamellar liposomes, (3) coupled to keyhole limpet hemocyanin (KHL), and (4) incorporated into a tetrameric branched lysine core. The highest anti-VP1 peptide responses were generated by synthetic peptides entrapped into liposomes and coupled to KLH. No anti-HAV response was generated with the free peptide, while all the other forms induced both anti-HAV and HAV-neutralizing antibodies. Maximum neutralization indices were observed in ascites from mice treated with liposome-entrapped and KLH peptides.

Adjuvants, Immunologic↗
PubMed1995

Genotyping of rotaviruses isolated from sewage.

Rotaviruses from environmental samples have been genotyped by a seminested reverse transcription PCR assay with serotype-specific primers derived from variable regions of gene 9, which produce different characteristic segment sizes for serotypes 1 to 4. The method enabled the detection and identification of type 1, 2, and 3 group A rotaviruses in sewage.

Genotype↗
PubMed1995

Changes in core histone variant composition in differentiating neurons: the roles of differential turnover and synthesis rates.

The core histone classes H2A, H2B, H3, and H4 are the main group of proteins responsible for the folding of DNA in nucleosomes. Each of the core histone classes except H4 is composed of nonallelic variants. The core histone variant composition changes during postnatal development in rat cerebral cortex neurons; H2A.1, H2B.1, H3.1 and H3.2 decay exponentially, whereas H2A.2, H2A.x, H2B.2, and H3.3 accumulate. H2A.z is the only variant that remains constant. We have studied the synthesis of core histone variants in cortical neurons and their neuroblasts by in vivo labeling with [14C]lysine. The variant synthesis pattern of neuroblasts has been determined by labeling gravid rats during the period of proliferation of the brain cortical neurons of the fetuses, and synthesis in neurons has been studied by postnatal labeling. The incorporation of H2A.1 is about twice that of H2A.2, both in neurons and neuroblasts. Despite its higher synthesis rate, the proportion of H2A.1 decreases during postnatal development indicating that the turnover of H2A.1 is faster than that of H2A.2. Differential turnover and a change in synthesis rate are both involved in determining the relative concentrations of H2B.1 and H2B.2 in neurons. H3.1 and H3.2 are synthesized in neuroblasts, but not in neurons, and are thus replaced by H3.3 in neuronal chromatin. The fact that the synthesis pattern of immature neurons from newborns does not differ from that of mature neurons indicates that the changes in the synthesis pattern of core histones occur at the arrest of cell proliferation and are unrelated to the state of differentiation of the cells.

Animals↗
PubMed1995

Solid phase synthesis and immunogenicity of a VP3 peptide from hepatitis A virus.

The synthesis of a peptide belonging to the VP3 capsid protein of Hepatitis A virus has been accomplished by the continuous flow Fmoc-polyamide solid phase method. The use of methoxytrimethylbenzenesulphonyl (Mtr) and pentamethylchromansulphonyl (Pmc) as arginine side-chain protecting groups in the presence of tryptophan without lateral protection or protected with t-Boc is discussed. The synthetic VP3 peptide has been administered to mice in different forms: (i) free, (ii) coupled to keyhole limpet hemocyanin, (iii) encapsulated in multilamellar (MLV) liposomes, and (iv) incorporated to a tetrameric branched lysine core. The immune response induced by these preparation is reported.

Animals↗
PubMed1994

New alleles at microsatellite loci in CEPH families mainly arise from somatic mutations in the lymphoblastoid cell lines.

In the analysis of 40 CEPH families, under the EUROGEM project, with a total of 29 microsatellites (26 CA-repeats, a TCTA-repeat within the vWFII-3 gene, a TTA-repeat within the PLA-2 gene, and an AAAT-repeat intragenic to the NF1 gene) from human chromosomes 12, 17, and 21, we have detected 21 cases of abnormal segregation of alleles in 16 pedigrees for a total of 14 markers (48%). In 11 cases, the abnormal transmissions were of somatic origin, 10 of which (91%) occurred in the lymphoblastoid cell lines. In 9 other cases, it was not possible to determine if the origin of the new alleles was somatic or germline, and in one case hemizygosity in several family members was observed, so its origin was germline. The 20 new mutations detected in the 22,852 meioses analysed represent a mutation frequency of 8.7 x 10(-4) per locus per allele. The germline mutation rate could be as high as 3.9 x 10(-4) per locus per gamete (from 0 to 3.9 x 10(-4)), but the rate of somatic mutations detected in the study was much higher (4.8 x 10(-4) to 8.7 x 10(-4) per locus per allele). Individual mutation rates ranged from 0 to 3.8 x 10(-3). Among the markers analysed, all three that were tri- or tetranucleotide repeats showed one or two new alleles, compared to only 10 of the 26 (38%) CA-repeats showing mutations. Three CEPH families (102, 45 and 1333) each had several mutational events, and one individual (10210) had somatic mutations for two microsatellites from different chromosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Use of the colonic carcinoma cell line CaCo-2 for in vivo amplification and detection of enteric viruses.

The use of the continuous cell line CaCo-2 as an in vivo amplification system for the detection of fastidious human enteric viruses is reported. CaCo-2 cells showed an increased sensitivity to laboratory strains of group A rotavirus 3, reovirus 3, astrovirus 1, poliovirus 1, coxsackievirus A 24, enterovirus 70, and adenovirus 5, 40 and 41, when compared to a routine host cell line for each virus. Nucleic acids from wild-type infectious rotavirus, astrovirus, and adenovirus 40 in stool samples of patients with acute gastroenteritis could be amplified after infection of CaCo-2 cells with trypsin-pre-treated virus inocula. Virus diagnosis was carried out subsequently by dot-blot hybridisation with specific cDNA probes. An amplification factor between 10 and 1,000x was obtained by infection of CaCo-2 cells, thus enabling specific detection of low numbers of a wide range of enteric viruses, and the differentiation between infectious and noninfectious particles.

Adenocarcinoma↗
PubMed1994

Three CA/GT repeat polymorphisms from loci D21S414 and D21S1234 on human chromosome 21.

We report three new polymorphic CA repeat microsatellites (ABM-21, ABM-C37A, and ABM-C37B) in two different loci (D21S414 and D21S1234), located in bands q21 and q11.2 of human chromosome 21 (HC21) and that were isolated from a HC21 phage library (LA21NS01). Heterozygosities for ABM-21, ABM-C37A, and ABM-C37B were 0.74, 0.50, and 0.67 respectively. These three CA repeat markers should be useful in the construction of a high resolution genetic map of this region of HC21.

Base Sequence↗
PubMed1994

Structures associated with the expression of rabies virus structural genes in insect cells.

When rabies virus structural genes were expressed in insect cells, major observed alterations were a high level of cytoplasmic vacuolization caused by the matrix protein M2 and the glycoprotein G. Ring-like structures, 16 nm in diameter, were observed in cell-free extracts from insect cells that expressed the N protein alone. Hexagonally shaped structures, 16-20 nm in diameter, and regular lattice aggregates of the same structures appeared on co-expression of N and M1 proteins. Co-expression of the four structural proteins led to the formation of cell surface blebs containing the structures corresponding to N and M1 proteins.

Animals↗
PubMed1994

Survival of enteric viruses on environmental fomites.

The survival of human enteric viruses on several porous (paper and cotton cloth) and nonporous (aluminum, china, glazed tile, latex, and polystyrene) environmental surfaces has been evaluated. Viruses persisted for extended periods on several types of materials commonly found in institutions and domestic environments. The stability of the viruses was generally influenced by environmental factors such as relative humidity (RH), temperature, and the type of surface contaminated. Overall, hepatitis A virus (HAV) and human rotavirus (HRV) were more resistant to inactivation than enteric adenovirus (ADV) and poliovirus (PV). The resistance to the desiccation step appears to be of major significance in determining the survival of a virus dried on fomites. ADV and PV showed a pronounced decrease in titer at this stage, whereas HAV and HRV displayed little decay at the desiccation step. HAV and HRV persistence was not affected by the presence of fecal material. On nonporous surfaces, PV and ADV persisted better in the presence of feces. However, on porous fomites the presence of fecal material had a negative influence on the survival of PV and ADV. Except for HRV, greater virus survival was observed at 4 degrees than at 20 degrees C. PV and HAV survival was enhanced at high RH; the survival of the latter was enhanced at least for nonporous materials. When dried on porous materials, HRV also exhibited greater persistence at high RH. The survival of ADV was not affected by RH. The validity of using bacteriophages of Bacteroides fragilis as indicators of human viruses dried on fomites was evaluated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoviruses, Human↗
PubMed1994

Disinfection of human enteric viruses in water by copper and silver in combination with low levels of chlorine.

The efficacy of copper and silver ions, in combination with low levels of free chlorine (FC), was evaluated for the disinfection of hepatitis A virus (HAV), human rotavirus (HRV), human adenovirus, and poliovirus (PV) in water. HAV and HRV showed little inactivation in all conditions. PV showed more than a 4 log10 titer reduction in the presence of copper and silver combined with 0.5 mg of FC per liter or in the presence of 1 mg of FC per liter alone. Human adenovirus persisted longer than PV with the same treatments, although it persisted significantly less than HRV or HAV. The addition of 700 micrograms of copper and 70 micrograms of silver per liter did not enhance the inactivation rates after the exposure to 0.5 or 0.2 mg of FC per liter, although on some occasions it produced a level of inactivation similar to that induced by a higher dose of FC alone. Virus aggregates were observed in the presence of copper and silver ions, although not in the presence of FC alone. Our data indicate that the use of copper and silver ions in water systems may not provide a reliable alternative to high levels of FC for the disinfection of viral pathogens. Gene probe-based procedures were not adequate to monitor the presence of infectious HAV after disinfection. PV does not appear to be an adequate model viral strain to be used in disinfection studies. Bacteroides fragilis bacteriophages were consistently more resistant to disinfection than PV, suggesting that they would be more suitable indicators, although they survived significantly less than HAV or HRV.

Adenoviruses, Human↗
PubMed1994

Mutational analysis of ERCC3, which is involved in DNA repair and transcription initiation: identification of domains essential for the DNA repair function.

The human ERCC3 gene, which corrects specifically the nucleotide excision repair defect in human xeroderma pigmentosum group B and cross-complements the repair deficiency in rodent UV-sensitive mutants of group 3, encodes a presumed DNA helicase that is identical to the p89 subunit of the general transcription factor TFIIH/BTF2. To examine the significance of the postulated functional domains in ERCC3, we have introduced mutations in the ERCC3 cDNA by means of site-specific mutagenesis and have determined the repair capacity of each mutant to complement the UV-sensitive phenotype of rodent group 3 cells. A conservative substitution of arginine for the invariant lysine residue in the ATPase motif (helicase domain I), six deletion mutations in the other helicase domains, and a deletion in the potential helix-turn-helix DNA-binding motif fail to complement the ERCC3 excision repair defect of rodent group 3 mutants, which implies that the helicase domains as well as the potential DNA-binding motif are required for the repair function of ERCC3. Analysis of carboxy-terminal deletions suggests that the carboxy-terminal exon may comprise a distinct determinant for the DNA repair function. In addition, we show that a functional epitope-tagged version of ERCC3 accumulates in the nucleus. Deletion of the putative nuclear location signal impairs neither the nuclear location nor the repair function, indicating that other sequences may (also) be involved in translocation of ERCC3 to the nucleus.

Amino Acid Sequence↗