PubMed Health⌕ Search

Biomedical subjects

D Gillet

Publications and source records attributed to D Gillet.

At least 19 recordsLinked to original sources
PubMed2003

Clinical evaluation of the Carisolv chemomechanical caries removal technique according to the site/stage concept, a revised caries classification system.

The objective of the present study was to assess the efficiency and benefit of a chemomechanical system for carious dentin removal, Carisolv, in general practice. A revised caries classification, the site/stage concept, was used to describe the clinical situations of all carious lesions treated. The study was performed by 12 investigators, and 120 carious lesions were treated with Carisolv. Sixty percent of the cases were treated without anaesthesia, and we found a significant correlation between chemomechanical treatment without anaesthesia and absence of pain ( P=0.01). In 78.3% of the cases, carious dentin was totally removed with Carisolv, and in 21.7%, the dentin treatment was completed by drilling. In cases performed with Carisolv alone, the time required to remove carious dentin was 11.1+/-9.51 min (mean+/-SD). Treatment time was equivalent for all sites and increased significantly with each successive stage of lesion progression ( P<0.001). In 82.5% of cases, the clinicians were satisfied with Carisolv, and in 99.2%, so were the patients. We conclude that, using clinical examination methods, Carisolv seems to remove carious dentin at all sites and stages of carious lesions but must be made more efficient for use in general practice.

Adolescent↗
PubMed2002

Microleakage and penetration depth of three types of materials in fissure sealant: self-etching primer vs etching: an in vitro study.

Clinical preventive procedures must be done after a risk assessment. One of the risk factors is the occlusal morphology of the posterior teeth. These caries-free fissures must be sealed. This first in vitro experimentation of the study evaluated the microleakage and the penetration depth of three types of materials by Vivadent: Helioseal F, Tetric, Tetric Flow. The teeth were etched with phosphoric acid and bonded using a one bottle bonding in order to determine the best material for the sealing of the fissure. The depth of penetration of fuschine dye as well as that of the tested material was measured with a grid. The results, compared to the depth of the fissures, are expressed in percentage of penetration. The results were as follows: penetration of fuschine dye: 0% for the 2 composites, 100% for Helioseal F; penetration of the materials: 96.90% for Helioseal F, 70.82 for Tetric and 86.10 for Tetric Flow (significant difference, Wilcoxon test = 0.0105). In this first in vitro study, Tetric Flow shows no microleakage and is more efficient when compared to Helioseal F and Tetric in obturating deep fissures of non carious bicuspids. The second experiment of the study evaluated the microleakage and the penetration depth of Tetric Flow when it is bonded by two different methods: Group 1: total etch (phosphoric acid) and Scotch-bond 1 (3M), and Group 2: self-etching primer with Prompt (Espe). There was no significant difference (p > 0.03) between classical bonding vs self-etching primer. The self-etching primer Prompt is very efficient vs phosphoric acid in obturating the fissures of non carious bicuspids with Tetric Flow. It is concluded that for prevention by sealing, using a flowable ceromer (Tetric Flow) with the self-etching (Prompt), is a really good technique.

Acid Etching, Dental↗
PubMed2002

[Patients, practitioners, faculty and dental esthetics: the same level of perception?].

The aim of this study was to evaluate the importance of the dental aesthetic for the patients, the dental surgeon and the dental teachers by the study of the consultation reason, the complaints, the post-university congress program, the practical program of the dental students and the programs of the IADR congress. It appears that in odontology, patients ask strongly for aesthetic care, in consultation and litigation. The content of congress and professional literature shows that dental surgeons answer to that request. Only the practical teaching was a bit less but it was recently modify. The research workers are also very interesting for aesthetic care.

Attitude of Health Personnel↗
PubMed2002

[Water absorption of five dental resins used in bonded restorations].

The actual restorative dentistry need to bond material which are under the constraint of saliva likely, as all liquid, to enter inside the product with time and to modify its characteristics. In this study, we compare the behaviour of five materials opposite water absorption, in vitro, until one year: two composite resins (Tetric et Pertac II), two ceromer (ceromer (Tetric ceram et Tetric flow) and one compomer (Hytac(r)). Each pastille weight is expressed in percentage of initial weight. All materials loose weight in the first hours except Tetric ceram which stay stable. At 48 h, all materials except Pertac II get back their initial weight. At long-term, all the materials are stable with a profit of 1% for Hytac, 0.5% for Tetric, Tetric ceram et Tetric flow and a loss of à 0.3% for Pertac II. As a result of this study, we understand why the clinical used of Hytac must be done following strict conditions.

Absorption↗
PubMed2001

Comet assay and early apoptosis.

The comet assay is a single cell gel electrophoresis test currently used as a qualitative and quantitative genotoxicity test. However, some of the results from this comet assay and current knowledge on apoptosis lead us to suspect the presence of some false positive results. The aim of this study was to ascertain if apoptotic cells can yield comet images that might distort the interpretation of the results. Using Jurkat cells, that hardly express Fas antigen, and apoptosis induction with anti-Fas antibody, it was possible to show that apoptosis can generate typical comet pictures as soon as the cells enter the apoptosis process. Therefore, comet images cannot be interpreted as a genotoxicity indicator when an apoptosis risk is present. Yopro-1 staining, that is also nearly immediate after apoptosis induction, can be used to balance comet assay results.

Apoptosis↗
PubMed2001

Prolonged display or rapid internalization of the IgG-binding protein ZZ anchored to the surface of cells using the diphtheria toxin T domain.

We have shown previously that the diphtheria toxin transmembrane domain (T) may function as a membrane anchor for soluble proteins fused at its C-terminus. Binding to membranes is triggered by acidic pH. Here, we further characterized this anchoring device. Soluble proteins may be fused at the N-terminus of the T domain or at both extremities, without modifying its membrane binding properties. This allows one to choose the orientation of the protein to be attached to the membrane. Maximum binding to the cell surface is reached within 1 h. Anchoring occurs on cells previously treated with proteinase K, suggesting that T interacts with the lipid phase of the membrane without the help of cell surface proteins. Binding does not permeabilize cells or affect cell viability, despite the fact that it permeabilizes liposomes and alters their structure. When attached to L929 fibroblasts, the proteins are not internalized and remain displayed at their surface for more than 24 h. When bound to K562 myeloid cells, the molecules are internalized and degraded. Thus, depending on the cell type, soluble proteins may be anchored to the surface of cells by the T domain for an extended time or directed towards an internalization pathway.

Animals↗
PubMed2001

Improving standards in the treatment of acute otitis externa by the use of a treatment protocol and open access to aural toilet.

A prospective audit of the procedure and outcome in the management of acute otitis externa was undertaken in our unit. The first cycle demonstrated a heterogeneous approach and clinical isolation of junior staff. A questionnaire survey of local general practitioners highlighted clinical confusion over the use of topical medication and a need for improved access to facilities for aural toilet. General practitioner liaison and education was an essential component in formulating a change in practice. In particular, open access for aural toilet was introduced and utilization encouraged. Following changes in practice, the second cycle of the audit showed that treatment protocols were effective and adhered to by junior staff.

Acute Disease↗
PubMed2001

[Anchoring cytokines to cancer cells using diphtheria toxin: better than immunotherapy by gene transfer?].

Many cytokines are able to stimulate the antitumor immune response. However, in order to avoid the toxic effects due to systemic injection, it is necessary to concentrate the cytokines in the tumor microenvironment. Current methods, based on the transfer of cytokine genes into tumor cells, still suffer drawbacks. We describe an alternative approach using recombinant cytokines genetically conjugated to a membrane anchor derived from diphtheria toxin. Interleukin-2 anchored to lymphoma and melanoma cells remained displayed on their surface and were not internalized. Injection of these cell preparations to mice led to an immune response able to prevent or slow tumor growth following tumor challenge.

Animals↗
PubMed1998

Anchoring antibodies to membranes using a diphtheria toxin T domain-ZZ fusion protein as a pH sensitive membrane anchor.

We have constructed a fusion protein, T-ZZ, in which the IgG-Fc binding protein ZZ was fused to the C-terminus of the diphtheria toxin transmembrane domain (T domain). While soluble at neutral pH, T-ZZ retained the capacity of the T domain to bind to phospholipid membranes at acidic pH. Once anchored to the membrane, the ZZ part of the protein was capable of binding mouse monoclonal or rabbit polyclonal IgG. Our results show that the T-ZZ protein can function as a pH sensitive membrane anchor for the linkage of IgG to the membrane of lipid vesicles, adherent and non-adherent cells.

Animals↗
PubMed1998

The diphtheria toxin transmembrane domain as a pH sensitive membrane anchor for human interleukin-2 and murine interleukin-3.

We have constructed two fusion proteins T-hIL-2 and T-mIL-3 in which human interleukin-2 (hIL-2) or murine interleukin-3 (mIL-3) are fused to the C-terminus of the diphtheria toxin transmembrane domain (T domain). Two additional fusion proteins, T-(Gly4-Ser)2-hIL-2 and T-(Gly4-Ser)2-mIL-3, were derived by introduction of the (Gly4-Ser)2 spacer between the T domain and cytokine components. Recognition of the hIL-2 receptor or the mIL-3 receptor by the corresponding recombinant proteins was demonstrated by their capacity to stimulate cytokine-dependent cell lines. All proteins retained the capacity of the T domain to insert into phospholipid membranes at acidic pH. Finally, anchoring of both cytokines to the membrane of lipid vesicles or living cells was assessed by specific antibody recognition. Our results show that the T domain fused to the N-terminus of a given protein can function as a pH sensitive membrane anchor for that protein.

Animals↗
PubMed1997

Characterization and receptor specific toxicity of two diphtheria toxin-related interleukin-3 fusion proteins DAB389-mIL-3 and DAB389-(Gly4Ser)2-mIL-3.

We have constructed two fusion proteins, DAB389-mIL-3 and DAB389-(Gly4Ser)2-mIL-3, in which the receptor-binding domain of diphtheria toxin is replaced by mouse interleukin-3 (IL-3). Cytotoxic activity of the fusion toxins was observed on three out of six cell lines assayed. This toxicity was mediated through binding to the IL-3 receptor as it was inhibited in a dose-dependent manner with murine IL-3 or anti-IL-3 neutralizing antibodies. DAB389-(Gly4Ser)2-mIL-3 was up to 5 times more toxic than DAB389-mIL-3, depending on the cell line (0.8 x 10(-10) M < IC50 < 3 x 10(-10) M). These proteins can be used for the detection of IL-3 receptors on mouse cells and should allow for the selective elimination of IL-3 receptor-positive pluripotent hematopoietic stem cells prior to bone marrow transplantation.

Animals↗
PubMed1997

Clostridium perfringens epsilon-toxin acts on MDCK cells by forming a large membrane complex.

Epsilon-toxin is produced by Clostridium perfringens types B and D and is responsible for a rapidly fatal enterotoxemia in animals, which is characterized by edema in several organs due to an increase in blood vessel permeability. The Madin-Darby canine kidney (MDCK) cell line has been found to be susceptible to epsilon-toxin (D. W. Payne, E. D. Williamson, H. Havard, N. Modi, and J. Brown, FEMS Microbiol. Lett. 116:161-168, 1994). Here we present evidence that epsilon-toxin cytotoxic activity is correlated with the formation of a large membrane complex (about 155 kDa) and efflux of intracellular K+ without entry of the toxin into the cytosol. Epsilon-toxin induced swelling, blebbing, and lysis of MDCK cells. Iodolabeled epsilon-toxin bound specifically to MDCK cell membranes at 4 and 37 labeled C and was associated with a large complex (about 155 kDa). The binding of epsilon-toxin to the cell surface was corroborated by immunofluorescence staining. The complex formed at 37 degrees C was more stable than that formed at 4 degrees C, since it was not dissociated by 5% sodium dodecyl sulfate and boiling.

Animals↗
PubMed1994

Recombinant technology in the preparation of immunogen and enzymatic tracer. Application to the development of an enzyme immunoassay for rat prolactin.

A competitive enzyme immunoassay for rat prolactin using an immunogen and a tracer obtained by recombinant DNA technology is described. Polyclonal antibodies were raised in rabbits immunized with a purified chimeric protein consisting of rat prolactin fused with two synthetic immunoglobulin G binding domains derived from staphylococcal Protein A. The enzymatic tracer was obtained using an expression system which permits insertion of rPRL DNA sequence in the alkaline phosphatase gene. Antibodies and tracer were used to develop a solid-phase competitive immunoassay for the measurement of rat prolactin in plasma with a minimal detectable concentration of 0.5 ng/ml. The mean intra- and inter-assay coefficients of variation were 7.8 and 13.2%, respectively. Rat plasma concentrations measured with this assay correlated well with those obtained with a conventional enzyme immunoassay (r = 0.993, slope = 1.037, n = 24).

Alkaline Phosphatase↗
PubMed1993

Enzyme immunoassay using a rat prolactin-alkaline phosphatase recombinant tracer.

This paper describes a competitive enzyme immunoassay of rat prolactin (rPrl) using a recombinant conjugate as a colorimetric tracer. rPrl was inserted into the N-terminal end of Escherichia coli alkaline phosphatase (AP), using an expression vector which allows insertion of foreign DNA sequences between codons +6 and +7 of the phoA gene. The assay was performed in 96-well microtiter plates coated with a mouse monoclonal antibody raised against rabbit immunoglobulin G. Each component (recombinant tracer, rabbit antiserum against rPrl, and rPrl standard) was added in a volume of 50 microL. The sensitivity of the assay was sufficiently high to allow titration of rPrl in plasma. The detection threshold was 15 pg (0.3 ng/mL) and the B/B0 50% value was 150 pg (3 ng/mL). The intraassay coefficient of variation was less than 10% over a wide range of rPrl concentrations (2.9-50 ng/mL). The interassay coefficient of variation was less than 15% for rat plasma samples in the concentration range of 4-40 ng/mL. The good parallelism observed between the standard curve and sample dilution curves showed that the immunoreactivity in rat plasma behaves like standard rPrl. Together with recovery experiments, these results indicated that assay without extraction is possible. A single immunoreactive peak that comigrates with standard rPrl is observed after molecular sieve fractionation of plasma samples. The reliability of the assay was confirmed by good correlation with conventional radioimmunoassay (r = 0.996, slope 0.978).

Alkaline Phosphatase↗
PubMed1993

Recombinant colorimetric antibodies: construction and characterization of a bifunctional F(ab)2/alkaline phosphatase conjugate produced in Escherichia coli.

We have designed a vector which allows the synthesis in Escherichia coli of bifunctional F(ab)2-alkaline phosphatase conjugates. The vector contains a di-cistronic operon encoding truncated heavy chain (Fd or VH-CH1) of an IgG inserted between residues +6 and +7 of bacterial alkaline phosphatase (PhoA), and the light chain of the same IgG. We demonstrate the utility of this approach with the heavy and light chain domains of a snake toxin-specific monoclonal antibody, M alpha 2-3. We show that the VH-CH1-PhoA hybrid and VL-CL are concomitantly expressed and exported to the periplasm of E. coli where they form a disulfide-linked chimeric protein. The hybrid has the same affinity as M alpha 2-3 for the snake toxin antigen and possesses PhoA enzymatic activity.

Alkaline Phosphatase↗
PubMed1993

Biochemical and functional characteristics of soluble MHC molecules derived from H-2Ld/Q10d chimeric gene.

We have constructed a chimeric class I gene in which the 5' half of the H-2Ld gene is linked to the 3' half of Q10d. The resulting H-2Ld/Q10d protein is homologous to the native H-2Ld heavy chain for the three external domains except for an Arg to His substitution at position 260. The transmembrane and intracytoplasmic domains of the H-2Ld chain are replaced by the short low hydrophobic transmembrane-like domain of the Q10d chain. Following DNA-mediated gene transfer into mouse L cells, transformants were selected for the presence of specific mRNA. Radiolabelling and immunoprecipitation analysis revealed secretion of a 48-46 kd chain weakly associated with beta 2-microglobulin. This molecule reacts with H-2Ld-specific mAb that identify determinants on the first and second domains as well as with an anti-Q10 carboxyl-terminal peptide antiserum, but is not recognized by a mAb specific for a determinant of H-2Ld third domain. The integrity of antibody reactivity of the first and second domains together with beta 2-microglobulin association suggest that our molecule may be considered a good soluble counterpart of the native membrane H-2Ld molecule with which to perform functional studies. In order to analyze the immunogenic capacities and T-cell recognition of the soluble H-2Ld molecules, T-cell lines were produced from mice of various inbred strains immunized with supernatant from H-2Ld/Q10d-transfected fibroblasts. Characterization of these T cells revealed that they expressed a CD4+CD8- phenotype, and recognized H-2Ld/Q10d products in a class II-restricted manner.

Animals↗