PubMed Health⌕ Search

Biomedical subjects

G Prevost

Publications and source records attributed to G Prevost.

52 records · Page 3Linked to original sources
PubMed1989

In vitro characterization of tissue-specific nuclear proteins preferentially bound to the mouse beta-globin gene during MEL cell terminal differentiation.

Using DNA restriction fragments of the mouse beta-globin gene and other promoter-containing DNA fragments (LTR-MMTV and pBR322) as controls, we have characterized by protein blotting, in extracts of mouse erythroleukemia (MEL) cells, specific nuclear DNA binding proteins with a preferential affinity for the beta-globin DNA. Some proteins (110 and 75 kDa) appear in differentiated MEL cells while others (100, 95, and 35 kDa) are present in immature MEL and normal erythroblast cells and bind selectively to the far-upstream region of the gene. These proteins could modulate either positively or negatively the expression of the beta-globin gene and maybe, of other genes, during the terminal differentiation of erythroid cells.

Animals↗
PubMed1989

Study of the arrangement of the functional domains along the yeast cytoplasmic aspartyl-tRNA synthetase.

Aspartyl-tRNA synthetase from yeast (AspRS) was screened for functional domains by measuring the effect of two types of amino acid mutations on its catalytic properties: (a) insertion of a dipeptide or a tetrapeptide along the polypeptide chain, (b) deletion of various lengths from the enzyme C-terminal. It was shown that insertion mutations significantly affect the kinetic properties of AspRS only when occurring in the second quarter of the molecule and the two centrally located mutations even inactivate the enzyme completely. Analysis of kinetic data strongly suggests that, in fact, all the observed activity modifications result from alteration of the activation reaction rate constant, kappa cat only. This led to the conclusion that the domain involved in aspartic acid activation should be located in the second quarter of the molecule. Furthermore, a deletion mutant with a modification of the last five amino acid residues was isolated. This mutant is fully active in the activation step, but has lost 80% of the wild-type aminoacylation activity. This involvement of the C-terminus in acylation implies that it has to be folded towards strategic regions of the enzyme, thus favouring conformations required for catalysis or maintaining the tRNA in a functional position.

Amino Acid Sequence↗
PubMed1989

South western blot mapping: a procedure for simultaneous characterization of DNA binding proteins and their specific genomic DNA target sites.

A method called "South Western blot mapping" for rapid characterization of both DNA binding proteins and their specific sites on genomic DNA is described. Proteins are separated on a sodium dodecyl sulfate (SDS) polyacrylamide gel, renatured by removing SDS in the presence of urea, and blotted onto nitrocellulose by diffusion. The genomic DNA region of interest is digested by restriction enzymes selected to produce fragments of appropriate but different sizes, which are subsequently end-labeled and allowed to bind to the separated proteins. The specifically bound DNA is eluted from each individual protein-DNA complex and analyzed by acrylamide gel electrophoresis. Evidence that tissue-specific DNA binding proteins may be detected by this technique is presented. Moreover, their sequence-specific binding allows the purification of the corresponding selectively bound DNA fragments and may improve protein-mediated cloning of DNA regulatory sequences.

Animals↗
PubMed1989

Synthetic exfoliative toxin A and B DNA probes for detection of toxigenic Staphylococcus aureus strains.

Two methods for the detection of exfoliative toxin (ET) from Staphylococcus aureus were compared: (i) a phenotypic assay, electrosyneresis, and (ii) a genotypic assay, staphylococcal DNA hybridization with oligodeoxynucleotide probes. The probes were chosen from the previously determined sequences of serotype A and B of ET, one probe for serotype A and another for serotype B. Strains exhibiting ET production in electrosyneresis always possessed the ET gene(s). Conversely, some strains not exhibiting ET production in electrosyneresis harbored the ET gene(s). The latter strains produced levels of ET. ET-negative phage group 2 strains of S. aureus as well as tested coagulase-negative staphylococci did not possess the ET gene(s). The sensitivity of the DNA hybridization technique was 10(6) bacteria or 100 ng of genomic DNA.

Bacterial Toxins↗
PubMed1981

[Contribution of contact lenses to the reduction of aniseikonia in myopic patients after unilateral cataract operations (author's transl)].

The most rapid method for determining the best mode of optical compensation in myopic patients following cataract operations was studied, by employing a graphic method for calculating theoretical aniseikonia and measuring subjective aniseikonia with a new stereo-projector. Several examples of the method chosen are given, this involving optical equipment--glasses, lens, myopisation--aniseikonia being reduced to a maximum.

Adult↗
PubMedDate not supplied

Piperacillin and netilmicin combination therapy for febrile episodes in neutropenic patients.

We assessed the efficacy of a piperacillin (3 x 4 g/d) and netilmicin (5 mg/kg/d) combination therapy for infections in febrile neutropenic patients. The study was conducted over a 30-month period and 203 patients were included. Bone marrow transplant recipients were not included in this study. Origin of infection was documented in 101 (50%) episodes: 33 fungal, viral or parasitic infections and 68 bacterial infections mainly composed of septicemia. Of the 169 evaluable patients with proved bacterial infections or non-documented infections, 129 (76%) recovered with the piperacillin and netilmicin combination treatment. All gram-positive bacterial infections failing first line therapy were cured after the addition of vancomycin. Piperacillin and netilmicin appeared very effective in this large monocentric prospective study. It does not seem necessary to include vancomycin in first line therapy of infections of the neutropenic patients in our institution; however, vancomycin must be added early in the case of suspected or documented staphylococcal infection failing empiric treatment.

Acute Disease↗