Biomedical subjects

Claire Toquet

Publications and source records attributed to Claire Toquet.

4 recordsLinked to original sources

PubMed2003

In situ immunophenotype of the inflammatory infiltrate in eosinophilic fasciitis.

OBJECTIVE: Eosinophilic fasciitis (EF) is histologically characterized by a fibrous and inflammatory thickening of subcutaneous septal-fascial-perimysial collagenous scaffold. This study aims to define the immunophenotype of inflammatory cells of fascia and muscle underlying the in situ immune response in EF. METHODS: In 11 cases of EF, we determined the phenotype of inflammatory cells, expression of MHC class I and class II antigens, and C5b9 membranolytic attack complex (MAC) deposits by immunohistochemistry analysis of fascia tissue. Muscle biopsies from 9 patients with active dermatomyositis and 5 with active polymyositis were used as controls. Results. In all patients but one, the inflammatory infiltrate was mainly composed of macrophages associated with CD8+ T lymphocytes (CD4/CD8 ratio < 1) and few eosinophils. Cytotoxic properties were found in 14% of CD8+ T lymphocytes, as shown by granzyme B expression. MHC Class I antigens were overexpressed (5/7) by muscle fibers, with a paratrabecular reinforcement in 4 cases. MHC class II antigens were not expressed by muscle fibers except in one case. C5b9 MAC deposits were not detected. CONCLUSION: Our in situ characterization of inflammatory infiltrate demonstrates the predominancy of macrophages and CD8+ T lymphocytes. Some of these CD8+ lymphocytes contain granzyme B, thus suggesting a cytotoxic cellular immune response in EF, which could be triggered by infectious or environmental agents.

CD4-CD8 Ratio↗

PubMed2003

Temporal arteritis associated with systemic necrotizing vasculitis.

OBJECTIVE: To evaluate the clinical and laboratory characteristics of patients with systemic vasculitis associated with temporal artery involvement. METHODS: From a cohort of 120 patients fulfilling American College of Rheumatology criteria for temporal arteritis, we retrospectively identified 7 patients with systemic necrotizing vasculitis associated with histological temporal arteritis. RESULTS: Among the 7 patients, 2 had classic polyarteritis nodosa, one had unclassified systemic vasculitis, one had Wegener's granulomatosis (WG), and 3 had microscopic polyangiitis. The mean age of the patients was 70.2 years, and cranial symptoms revealed the disease in all but one patient. Temporal arteritis was generally associated with extracephalic manifestations suggestive of systemic vasculitis. Antineutrophilic cytoplasmic antibodies were positive in 3 of the 4 patients with small vessel vasculitis. Pathologically, the main temporal artery was involved in all but one patient, with inflammatory infiltrate of vasa vasorum and adventitia associated in 5 with small tributary involvement. Fibrinoid necrosis was rare, observed in 2 specimens; 2 patients with unclassified systemic vasculitis and WG had a classic giant cell arteritis (GCA) histologic pattern. Only one patient had exclusive involvement of small vessels, surrounding the spared main temporal artery. Muscle biopsies showed histopathological evidence of vasculitis in 2 patients, skin biopsy in one, and vein biopsy in the other. CONCLUSION: Temporal artery involvement in systemic necrotizing vasculitis was generally associated with extracranial clinical features suggestive of systemic vasculitis. Temporal artery biopsy is a simple tool for diagnosis of vasculitis, but the histopathological findings do not always discriminate between necrotizing vasculitis and classic GCA.

Aged↗

PubMed2002

Growth phase-dependent expression of ICAD-L/DFF45 modulates the pattern of apoptosis in human colonic cancer cells.

The inhibitor of caspase-3-activated DNase (ICAD) is a caspase-3 substrate that controls nuclear apoptosis. ICAD has two isoforms: a functional isoform of M(r) 45,000, ICAD-L/DNA fragmentation factor (DFF) 45; and a M(r) 35,000 isoform, ICAD-S/DFF35. ICAD-deficient murine cells display resistance to apoptotic stimuli and absence of typical nuclear changes of apoptosis. Our aim was to: (a) characterize the ICAD expression in several human colonic cancer cell lines compared with human normal colonocytes; and (b) correlate the phenotypic features of apoptosis to the level of ICAD expression. ICAD expression was assessed by immunoblot analysis. Early markers of apoptosis of cultured cells included lactate dehydrogenase retention in dying cells, cytokeratin 18 cleavage, and caspase-3 activation. Nuclear markers of apoptosis were assessed by Hoechst staining of nuclei, electron microscopy, and DNA electrophoresis. Inhibition of caspases was performed using a broad-spectrum caspase inhibitor, z-Val-Ala-Asp-fluoromethyl ketone. ICAD expression was restricted to the functional ICAD-L/DFF45 isoform in colonic cancer cells as well as in human normal colonocytes. In a clonal derivative of HT29 cells (HT29-Cl.16E cells), ICAD expression was found to be down-regulated during the exponential phase of growth, and the cell death triggered by IFN-gamma, anti-Fas antibody plus Adriamycin was characterized by the expression of early markers of apoptosis, whereas the key nuclear features of apoptosis were absent. In contrast, exposure of confluent cells to this treatment led to a typical apoptotic nuclear fragmentation. Both forms of apoptosis, in exponentially growing and confluent cells, were sensitive to the broad spectrum inhibitor of caspases, z-Val-Ala-Asp-fluoromethyl ketone. Our findings support the concept that the expression of ICAD is essential to the execution of full-blown apoptosis in colonic cancer cells. Altogether, our results point to ICAD as a potential target for restoring a normal apoptotic signal transduction pathway in colonic cancer cells.

Apoptosis↗

PubMed2002

Elevated (> or = 10%) MIB-1 proliferative index correlates with poor outcome in gastric stromal tumor patients: a study of 35 cases.

Mitotic activity and tumor size are currently regarded as the most powerful prognostic indicators for patients with gastrointestinal stromal tumor (GIST). This retrospective study evaluated the prognostic accuracy of MIB-1 proliferative index (PI) in combination with these two indicators in 35 GIST patients. Within a high-risk group, determined initially by tumor size and mitotic count, overall survival was significantly shorter for patients whose tumors had PI > or = 10% MIB-1 positive cells. When tumor location (gastric versus small intestine) was taken into account, a combination of tumor size, mitotic count, and PI > or = 10% identified a subgroup of patients with significantly shorter survival for gastric (but not small intestinal) GIST. Based on our results, MIB-1 immunostaining, when used in combination with tumor size and mitotic count, appears to be a powerful tool for identifying patients, especially those with gastric tumors, at high risk of recurrence and early tumor-related death.

Adult↗