Biomedical subjects

Jean-Pierre Doucet

Publications and source records attributed to Jean-Pierre Doucet.

6 recordsLinked to original sources

PubMed2004

Differences in the expression of apoptotic proteins in Burkitt's lymphoma cell lines: potential models for screening apoptosis-inducing agents.

Mammalian cells undergo programmed cell death by orchestrated interactions involving multiple independent pathways. At least one of them, the p53-dependent pathway is commonly compromised in Burkitt's lymphoma (BL) cell lines. Differences in the integrity of this pathway in various BL cell lines have made them useful experimental models in understanding response to standard or novel antitumor drugs vis-a-vis the p53 pathway. Non-p53-dependent loss of apoptotic regulation also contributes to the genesis and/or progression of lymphomas and it is possible that BL cell lines also represent these models. We have characterized the expression of multiple apoptotic proteins in a panel of BL cell lines and describe cell lines with loss of cIAP1, cIAP2, Bax, Bak, Bcl-Xs and p38 MAP-kinase. This data should make this panel of cell lines a useful screening system for testing novel apoptotic inducers.

Apoptosis↗

PubMed2003

MASSIS: a mass spectrum simulation system 1. Principle and method.

A mass spectrum simulation system was developed. The simulated spectrum for a given target structure is computed based on the cleavage knowledge and statistical rules established and stocked in pivot databases: cleavage rule knowledge, function groups, small fragments and fragment-intensity relationships. These databases were constructed from correlation charts and statistical analysis of large population of organic mass spectra using data mining techniques. Since 1980, several systems were proposed for mass spectrum simulation, but in present there is no any commercial software available. This shows the complexity and difficulties in the development of a such system. The reported mass spectral simulation system in this paper could be the first general software for organic chemistry use

Journal Article↗

PubMed2003

MASSIS: a mass spectrum simulation system. 2: Procedures and performance.

The use of the mass spectral simulation system, MASSIS, is reported and its performance has been evaluated. The search for substructures matching with fragments stored in four pivot databases was realised using the Ullmann algorithm. Special cleavage rules, such as the McLafferty rearrangement, the retro-Diels-Alder reaction, elimination of a neutral small molecule and oxygen migration, are processed through shortest path and depth-first search algorithms. For a search in the database of small fragments, the key step is to determine the tautomeric fragments; then a match can be obtained using a subgraph isomorphism algorithm. A string match is used to determine peak intensity. If the limited environment of an atom is the same as that found in the database of relationships between fragment and intensity, this intensity value is assigned to the query atom. Performance in a set of tests is very important in evaluating the system performance. A comparison of peaks with an intensity greater than 5% (relative) shows that our system has a very high performance figure (> 90% ) for routine organic compounds.

Algorithms↗

PubMed2003

Spectral code index (SPECOIND): a general infrared spectral database search method.

A new spectral code that can be used by Relational Database Management Systems (RDBMS) as an index for infrared (IR) spectra searches in Relational Database (RDB) is presented and its suitability is evaluated. Spectral codes are constructed for all spectra in the database as the spectral indexes and three query strings are created with the same theory used for the creation of the index code for the query spectrum. Some effects of parameters used to create index strings and query strings are discussed. All spectral searches are accomplished in structured query language (SQL) approach and the utilization examples of SQL have been shown. The sequential application of this procedure can reduce the original library of about 18000 spectra to a few spectra that can be used as references for subsequent detailed comparison. The software developed for the proposed system is particularly suitable for spectral search and structure interpretation.

Algorithms↗

PubMed2003

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and Fas apoptosis in Burkitt's lymphomas with loss of multiple pro-apoptotic proteins.

BACKGROUND AND OBJECTIVES: Normal B-cells in the germinal center (GC) may be exposed to both tumor necrosis factor-related apoptosis inducing ligand (TRAIL) and Fas-L. Whether abrogation of TRAIL apoptosis is a feature in the genesis of B cell lymphomas of GC-phenotype is not known. We assessed the integrity of the TRAIL pathway in Fas-resistant and Fas-sensitive Burkitt s lymphomas (BLs). DESIGN AND METHODS: Expression of TRAIL receptors was determined by flow cytometry and Western blots. The extent of apoptosis following exposure to TRAIL was measured by annexin-V/propidium iodide dual staining. The integrity of the Fas and TRAIL apoptotic pathways was determined by Western blotting to assess cleavage of downstream caspases. Western blot analyses were used to determine the expression of pro- and anti-apoptotic proteins and the profile of expression was correlated with response to TRAIL and CH11. RESULTS: Our results demonstrate that BL expresses both functional and decoy TRAIL receptors. BLs with a functional Fas pathway retained sensitivity to TRAIL: Frequent and compound loss of expression of pro-apoptotic proteins can be identified in BLs resistant to Fas. However, loss of Bax, Bak and Bcl-Xs did not compromise sensitivity to TRAIL: INTERPRETATION AND CONCLUSIONS: Our results indicate that BLs frequently retain sensitivity to the TRAIL pathway. These results underscore the utility of TRAIL-based therapeutic strategies in the treatment of those B-cell lymphomas that may have compromised expression of several pro-apoptotic proteins.

Apoptosis↗

PubMedDate not supplied

SIRS-SS: a system for simulating IR/Raman spectra. 2. Procedures and performance.

This paper is devoted to the description of procedures used in our IR/RAMAN spectrum simulation system, based on substructure/subspectrum correlations established between linked databases. The search is performed in the following order: small molecules/specific fragments/atom centered FRELs (FREL: FRagment centered on an Environment which is Limited)/bond focused FRELs. Comparative study with several reported methods has been carried out to show good performance of this software both for IR and RAMAN spectrum simulation.

Journal Article↗