PubMed Health⌕ Search

Biomedical subjects

D Bonnin

Publications and source records attributed to D Bonnin.

6 recordsLinked to original sources
PubMed1999

Ontogeny of synonymous T cell populations with specificity for a self MHC epitope mimicked by a bacterial homologoue: an antigen-specific T cell analysis in a non-transgenic system.

By means of a novel technique for identification and isolation of MHC class II-restricted antigen-specific T cells, we describe here in non-transgenic BALB / c mice physiological positive selection of an oligoclonal population of T cells which recognizes both a self MHC-derived peptide (Ialpha52) and a bacterial homologoue (Hi15). The results support a model for self peptide-mediated generation of T cells which have specificity for microbial antigens through molecular mimicry. This mechanism may be a model for the ontogeny of a physiological T cell response to infectious agents. Loss of control of these circuits may be part of the inciting factors of autoimmunity.

Animals↗
PubMed1999

Modeling EPR powder spectra using numerical diagonalization of the spin hamiltonian

A new modeling code, ZFSFIT (standing for Zero Field Splitting FITting), written in FORTRAN 77 is proposed. It is designed for computing and fitting EPR powder spectra described by any spin Hamiltonian including second- and fourth-order ZFS terms (S </= 52) and/or a hyperfine term (I </= 72). Based on numerical diagonalization of the spin Hamiltonian, this code computes the powder spectrum, the calculated angular dependencies, and the energy levels at any orientation. Least-squares refinement of the spin Hamiltonian parameters is performed either by adjusting powder line positions (EPRPLP module) or by directly fitting the powder spectra (ZFSFIT code). Especially, simultaneous fitting of EPR powder line positions recorded at distinct frequencies improves the accuracy of the refined EPR parameters. Superhyperfine effects as well as broadening effects due to site-to-site distribution of g-, A-, and ZFS parameters are treated using first-order perturbation theory and can also be refined. Parameters for several distinct centers can be fitted simultaneously, allowing quantification of their relative amounts in the sample. After a description of the algorithm, determination of second- and fourth-order ZFS parameters of Cr3+, Mn2+, and Fe3+ centers in low-symmetry sites in minerals are treated, including first evidence of structural Fe3+ centers in alphaAl(OH)3. The code is available without charge to academic users from the authors. Copyright 1999 Academic Press.

Journal Article↗
PubMed1998

Mucosal modulation of immune responses to heat shock proteins in autoimmune arthritis.

Induction of oral tolerance to antigens that are targets of self-reactive immune responses is an attractive approach to antigen-specific immune therapy of autoimmune diseases. Oral tolerization has indeed proven to be safe and effective in amelioration of autoimmune diseases in animal models. In humans, results have been somewhat controversial. The emphasis given to clinical outcome rather than to immunomodulation, and the difficulty in identifying appropriate candidate antigens contribute to the controversy. Heat shock proteins are promising targets for immune intervention. Immune reactivity to heat shock proteins has indeed been correlated with autoimmune arthritis in animal models, and abnormal immune responses to heat shock proteins have been described in human arthritis as well. Despite significant recent progress, little is known at a molecular level regarding the mechanisms which are responsible for a switch from autoimmunity to tolerance in humans. This is particularly true with respect to sequential analysis of several molecular and immunologic markers during both the course and treatment of disease. Novel approaches are currently under way to fill the gaps. We will briefly detail here the experience gained to date, and identify some of the avenues which future research will explore.

Administration, Oral↗
PubMed1990

Gallium-67 scan for distinguishing follicular hyperplasia from other AIDS-associated diseases in lymph nodes.

We have studied gallium-67 citrate scan (Ga-67) in the diagnosis of lymphadenopathy in patients with HIV-associated symptoms. Thirty HIV-infected patients with lymphadenopathy, fever and/or weight loss were evaluated with Ga-67. Lymph-node biopsy and/or needle aspirations were done in all patients. Twelve of 17 patients with grade 2 or 3 Ga-67 (uptake equal to or greater than that in the liver) had mycobacteriosis, three had lymphoma, one had Kaposi's sarcoma plus Castleman's disease and one had follicular hyperplasia. The three patients with grade 1 Ga-67 (uptake greater than that in soft tissue but less than that in the liver) had follicular hyperplasia. Of the 10 patients with grade 0 Ga-67 (less than or equal to that in soft tissue), nine had follicular hyperplasia and one had Kaposi's sarcoma. Sixteen of 17 patients with grade 2 or 3 Ga-67 versus one of 13 with Ga-67 grade 1 or 0 had diseases other than follicular hyperplasia (P less than 0.0001). Ga-67 may be a practical diagnostic tool in HIV-infected patients with lymphadenopathy and constitutional symptoms. A grade 1 or 0 Ga-67 suggests the presence of follicular hyperplasia, and lymph-node biopsy may be avoided unless Kaposi's sarcoma is suspected.

Adult↗
PubMed1968

[Not Available].

Explore the source record for details and available documents.

France↗