PubMed Health⌕ Search

Biomedical subjects

R Elkaim

Publications and source records attributed to R Elkaim.

14 recordsLinked to original sources
PubMed1997

Prevalence of six periodontal pathogens detected by DNA probe method in HIV vs non-HIV periodontitis.

OBJECTIVE: The aim of the study was to examine the prevalence of selected periodontal pathogens associated with HIV and non-HIV related periodontal lesions. METHODS: Subgingival plaque samples were obtained from both HIV-seropositive and HIV-seronegative patients affected with periodontal disease. DNA probes were used to detect Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus, Eikenella corrodens and Campylobacter rectus. RESULTS: A actinomycetemcomitans, P. intermedia and B. forsythus (P < 0.05) were more prevalent in HIV-seronegative patients with rapidly progressive periodontitis. Only C. rectus was slightly more prevalent in HIV-seropositive subjects with periodontal diseases, but this was not significant.

AIDS-Related Opportunistic Infections↗
PubMed1990

Hybricomb. A novel diagnostic tool for DNA probing.

A technique is described in which unlabeled DNA probes are immobilized on the plastic surface of a 12-tooth comb and used to capture homologs by a hybridization procedure. In the examples described, cellular DNA from cervical biopsies is chemically labeled using the Chemi-probe system. The sample containing labeled DNA is then hybridized with the immobilized unlabeled probe (reverse hybridization). By means of this technique, human papillomavirus sequences can be detected with a sensitivity comparable to that of radioactive probe procedures. DNA hybrids are visualized as colored spots on each tooth by moving the comb through the reagent solutions of the prefilled developing plate. The whole procedure requires less than 50 minutes hands-on time, and the results are obtained in a few hours. Application of the technique to the detection and typing of mycoplasma DNA is also reported.

Bacterial Typing Techniques↗
PubMed1985

Transcriptional analysis of the adenovirus-5 EIII promoter: absence of sequence specificity for stimulation by EIa gene products.

To identify the adenovirus-5 EIII promoter sequences that are involved in basal level of transcription, a series of promoter deletion mutants were analyzed in vivo by transfection into HeLa cells and in vitro using a HeLa whole cell extract system. Three regions within the EIII promoter were shown to be important for efficient transcription: the TATA sequence, an upstream element centered at -55/-57, and an additional element located between -111 and -233. In vivo transcriptional analysis of EIII promoter deletions in the presence of adenovirus EIa gene products have demonstrated that the same three regions are required for EIa-stimulated transcription. We conclude that there is no sequence element in the EIII promoter between -15 and -233 that is uniquely required for the stimulation of EIII transcription by EIa gene products.

Adenoviruses, Human↗
PubMed1984

Individual products of the adenovirus 12S and 13S EIa mRNAs stimulate viral EIIa and EIII expression at the transcriptional level.

Recombinant plasmids containing mutant or wild-type adenovirus serotype 2 EIa genes that produce the 12S mRNA alone, the 13S mRNA alone, or both mRNAs were cotransfected into HeLa cells with plasmids containing the viral EIIa or EIII transcription units. The amount of RNA produced from the EIIa and EIII promoters was increased by the products of both the 13S and the 12S RNAs. By measuring the level of specific transcription in nuclei isolated from transfected cells we directly demonstrate that the increased amount of EIIa RNA is due to stimulation of the rate of transcription.

Adenoviridae↗
PubMed1983

The adenovirus-2 EIIa early gene promoter: sequences required for efficient in vitro and in vivo transcription.

A series of deletion mutants extending from -250 toward the capsite has been constructed in the early promoter region of the adenovirus 2 EIIa gene and tested both in vitro, and in vivo after transfection of HeLa cells, for the ability to act as a template for transcription. A region between positions -94 and -63 upstream from the major EIIa early cap site is essential both in vivo and in vitro for efficient promoter function. By cotransfection of the EIIa deletion mutants with the EIa transcription unit it has been possible to demonstrate that deletion to position -94 does not affect induction of transcription of the EIIa early gene by the EIa transcription unit, but deletion to position -63 results in loss of detectable levels of EIIa early specific RNA. Thus, sequences upstream from position -94 of the EIIa early gene are not involved in the induction of the EIIa early gene by the EIa transcription unit.

Adenoviruses, Human↗
PubMed1981

Specific in vitro initiation of transcription on the adenovirus type 2 early and late EII transcription units.

Three transcription units are present in the adenovirus type 2 region EII. Transcription units EIIaE and EIIaL encode the mRNA for the 72,000-dalton DNA binding protein, early and late in the lytic cycle, respectively, and transcription unit EIIb encodes the mRNA for the protein that binds to the 5' termini of adenovirus DNA. By using a cell-free transcription system in the presence of purified RNA polymerase B (or II), we have obtained specific initiation of transcription from both the EIIaE promoter, which does not contain a T-A-T-A box, and the EIIaL promoter, which does. In addition, we have identified a new EII T-A-T-A box promoter that is located close to the early non-T-A-T-A box promoter and is used both in vivo and in vitro.

Adenoviruses, Human↗
PubMed1981

Protein kinases and their protein substrates in free messenger ribonucleoprotein particles and polysomes from mouse plasmacytoma cells.

In free messenger ribonucleoprotein particles (mRNP) and polysomes from plasmacytoma cells, a phosphorylated protein/protein kinase system has been characterized by a combination of oligo(dT)-cellulose chromatography and CsCl isopycnic gradient centrifugation. The presence phosphorylated in vivo has been detected in both types of particles. Endogenous protein phosphorylation occurs in vitro by particle-associated cAMP-independent protein kinase(s) using [gamma-32P]ATP and [gamma-32P]GTP. These kinases are sensitive to hemin action. Analysis of mRNP proteins by gel electrophoresis and autoradiography showed strong analogies between the phosphorylation patterns obtained in vivo and in vitro, suggesting a substrate specificity for the associated enzymes. The phosphorylated proteins have been compared to initiation factors and ribosomal proteins. We have partially purified the cAMP-independent protein kinase activities responsible for the endogenous phosphorylation in free mRNP and polysomes; two activities were identified in free mRNP whereas three activities were found to be associated with polysomes.

Adenosine Triphosphate↗
PubMed1979

mRNP proteins, initiation factors and phosphorylation.

Information has been collected to stimulate interest regarding the nature and the possible role of mRNP protein phosphorylation in a cytoplasmic control mechanism for protein synthesis. It does not imply a direct relationship between mRNP protein and initiation factors. These proteins have some properties in common (e.g. molecular weight, phosphorylation, protein kinase, mRNA binding activity). We emphasize that some free mRNP may be translatable after modification of their protein by interference factors belonging to other cellular compartments. Thus, some mRNP proteins might possess initiation factor or protein synthetic activity if we accept Spirin's theory, i.e., "Eukaryotic messenger RNA and informosomes omnia mea mecum porto.

Animals↗
PubMedDate not supplied

Adenosine diphosphate ribosyltransferase and protein acceptors associated with cytoplasmic free messenger ribonucleoprotein particles.

ADP-ribosyltransferase activity has been characterized in free messenger ribonucleoprotein particles (mRNP) from mouse plasmacytoma cells. This enzymatic activity appears to be associated with the free mRNP and not due to nuclear contamination. The enzyme activity is not stimulated by added DNA or histone H1 and represents 34 per cent of the total cellular ADP-ribosyltransferase activity while the DNA contamination in free mRNP is less than 4 per cent of the total cellular DNA. Moreover, the ADP-ribosyltransferase specific activity per mg of DNA is about 75-fold higher in free mRNP than in the nuclei. During CsCl gradient centrifugation of the cytoplasmic fraction, the ADP-ribosylated material separates out at a buoyant density similar to that of free mRNP. This ADP-ribosyltransferase activity is inhibited by thymidine, nicotinamide and 3-aminobenzamide, while it is highly stimulated by exogenous pancreatic RNase. The in vitro synthesized acid insoluble material is rendered partly soluble by treatment by a proteolytic enzyme or by snake venom phosphodiesterase resulting in phosphoribosyl-AMP formation: the pancreatic RNase does not solubilize this material. Several ADP-ribosylated proteins are detected by lithium dodecylsulfate gel electrophoresis. Such an ADP-ribosyltransferase activity has also been detected in free mRNP from rat liver. It is suggested that this ADP-ribosylation of specific free mRNP proteins may be associated with free mRNP structure and/or with some chemical covalent type of modification rendering mRNA available for translation.

Adenosine Diphosphate Ribose↗
PubMedDate not supplied

Active gamma-carboxylated human factor IX expressed using recombinant DNA techniques.

Factor IX (Christmas factor), a vitamin K-dependent plasma protein made in the liver, functions in the middle phase of the intrinsic pathway of blood coagulation. A functional deficiency of factor IX underlies haemophilia B, a chromosome X-linked recessive disease for which the major therapeutic approach is replacement treatment using factor IX concentrates. The cloning and characterization of the gene for human factor IX would mean that human factor IX could be produced in greater yield and purity through using recombinant DNA techniques. We have now used a human factor IX cDNA clone, inserted into a vaccinia virus-derived vector, to infect human hepatoma cells which normally produce no factor IX, and mouse fibroblasts. Fully active factor IX was produced by the hepatoma cells, whereas the fibroblasts produced a protein less active than natural factor IX, even in the presence of high levels of vitamin K. Human factor IX is extensively post-translationally modified, and thus represents probably the most complex protein produced in active form by recombinant DNA techniques to date. Our study also illustrates the potential of vaccinia virus-based vectors for expressing significant amounts of complex, clinically useful proteins in eukaryotic cells, in addition to its already demonstrated usefulness for producing live recombinant vaccines.

Animals↗