Cervical screening in Luxembourg: 1990–1999

For quality assurance purposes, the results of the 1990's obtained by the National Cervical Cancer Screening Programme (NCCSP) launched in 1962 were reviewed. The positive cytodiagnosis, the histologically verified in situ and invasive cervical cancers and the mortality rates were reported.     

Mutations that increase the mitotic stability of minichromosomes in yeast: characterization of RAR1

Summary In an attempt to identify proteins involved in the initiation of DNA replication, we have isolated a series of Saccharomyces cerevisiae mutants in which the function of putative replication origins is affected. The phenotype of these Rar^- (regulation of autonomous replication) mutants is to increase the mitotic stability of plasmids whose replication is dependent on weak ARS elements. These mutations are generally recessive and complementation analysis shows that mutations in several genes may improve the ability of weak ARS elements to function. One mutation (rar1-1) also confers temperature-sensitive growth, and thus an essential gene is affected. We have determined the DNA sequence of the RAR1 gene, which reveals an open reading frame for a 48.5 kDa protein. The RAR1 gene is linked to rna1 on chromosome XIII.     

Blastocystis hominis--a potential intestinal pathogen.

The parasite Blastocystis hominis has been found in 10% to 18% of stool specimens submitted to microbiology laboratories. Controversy exists as to whether this organism can cause illness in humans. We have reviewed the records of 65 symptomatic patients with B hominis in their stool. We conclude that B hominis is a potential pathogen that may or may not require drug therapy depending on the overall clinical circumstances, the severity of symptoms, and the presence of other pathogenic organisms.     

Activation of the phosphatidylinositol cycle in spreading cells

Metabolites of the phosphatidylinositol cycle were analyzed in BHK-21 (C13) cells spreading on fibronectin-coated culture plates in comparison with attached nonspreading cells 45 min after plating. Among the water-soluble metabolites (glycerophosphoinositol, inositol, inositol monophosphate, inositol bisphosphate, inositol trisphosphate, and inositol tetrakisphosphate), significant elevations were found for inositol monophosphate, inositol bisphosphate, and inositol tetrakisphosphate. In the lipid fraction, phosphatidylinositol 4-monophosphate and phosphatidylinositol 4,5-bisphosphate were significantly elevated. The activation of the phosphatidylinositol cycle in spreading versus nonspreading attached BHK-21 (C13) cells may be involved in the permissive effect of the extracellular matrix on cell proliferation.     

Fermentative degradation of nonionic surfactants and polyethylene glycol by enrichment cultures and by pure cultures of homoacetogenic and propionate-forming bacteria

Linear alkyl ethoxylates (polyethylene glycol alkyl ethers) were fermented completely to methane and CO2 in enrichment cultures inoculated with anoxic sewage sludge. Long-chain fatty acids were released as intermediates. No degradation was found with polypropylene glycol and polypropylene glycol-containing surfactants. Two types of primary ethoxylate-degrading bacteria were isolated and characterized. Both degraded polyethylene glycols with molecular weights of 1,000 completely. Strain KoB35 fermented polyethylene glycol, ethoxyethanol, and lactate to acetate and propionate and was assigned to the described species Pelobacter propionicus. Strain KoB58 converted polyethylene glycol and many other substrates to acetate only and was assigned to the genus Acetobacterium. The pathways of anaerobic degradation of nonionic surfactants are discussed with respect to their limitations and the various groups of bacteria involved.     

Flow cytometric evaluation of cell dispersion from human head and neck tumors

The preparation of single-cell suspensions from 25 human head and neck tumors is described. Dispersal was performed overnight at 4 degrees C under slight agitation of the tissue suspensions using various combinations of enzymes and additives. The cell suspensions were examined for number of cells released, viability, amount of debris, and DNA distribution by means of flow cytometry (FCM). It was shown that both trypsin/dithioerythritol (TD) and collagenase/D Nase (CDse) were of value in dispersing single cells from tumor tissue. In contrast to CDse, incubation with TD appeared to be cytolytic to normal lymphocytes. In a number of cases, DNA-FCM revealed ploidy abnormalities in a TD-suspension, which were not discernible in the concurrent CDse-suspension. Cell culture of primary cell suspensions corroborated the reliability of the DNA-FCM measurements. Pretreatment with CDse improved tumor disaggregation by TD and indicated a different dispersal capacity. Addition of Ca2+ and Mg2+ ions to the dispersal mixtures and preincubation of tumor slices in complete medium for 1 day before initiation of cell dispersion influenced favorably the quality of the cell suspension.     

Production of auto-anti-idiotypic antibody during the normal immune response: IX. Characteristics of the auto-anti-idiotype antibody and its production

Using hapten-reversible inhibition of plaque formation as an assay for auto-anti-idiotype antibody (anti-Id) and as a means for following idiotype (Id) expression, we have obtained evidence that following immunization with trinitrophenyl (TNP) conjugates (a) there are differences in Id expression in the anti-TNP antibody response to different TNP conjugates although there is some overlap; (b) different strains, although showing some differences in Id expression, tend to produce cross-reactive Ids, thus no obvious allotype linked inheritance of Id expression is observed in this heterogeneous immune response; (c) the auto-anti-Id produced following immunization with TNP-Brucella abortus or TNP-Ficoll tends to be of the IgG_2a and IgG_2b isotypes.     

Isolation, expression and characterization of a human apolipoprotein B 100-specific cDNA clone

The isolation and characterization of a human apolipoprotein B 100-specific cDNA clone (lambda gt-B1) containing a 1321 base pairs (bp) spanning insert is described. It encodes the 3'-nontranslated 281 bp long region up to the polyadenylation site and 1040 bp of the C-terminal coding region of 345 amino-acid residues of human apo B 100 and the stop codon. The lambda gt-B1 cDNA clone has been isolated from a human hepatoma cDNA expression library by immunoscreening using affinity-purified polyclonal anti apo B 100 antibodies. The nucleotide sequence of the apo B 100 insert has been determined. A part of the polypeptide sequence derived from this nucleotide sequence was identical with the amino-acid sequence obtained by protein sequencing of a purified cyanogen bromide fragment of apo B 100. The fusion protein consisting of beta-galactosidase and the 345 amino-acid residue long C-terminus of apo B 100 had an apparent molecular mass of 148 kDa in NaDodSO4 polyacrylamide gel electrophoresis. In Northern blot hybridization analysis the insert of the apo B 100-cDNA clone hybridized to a 20 to 22 kb mRNA from adult human liver.