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Biomedical subjects

B Mahé

Publications and source records attributed to B Mahé.

27 records · Page 2Linked to original sources
PubMed1995

High dose radiochemotherapy followed by autologous stem cell transplantation in four patients with multiple lymphomatous polyposis.

BACKGROUND: Multiple lymphomatous polyposis (MLP) results from gastrointestinal involvement by a B-cell lymphoma that originates from the mantle zone of lymphoid follicles. This well described clinicopathologic entity has a poor prognosis: the rate of complete response after conventional chemotherapy is very low. High dose radiochemotherapy with autologous stem cell transplantation (ASCT), which is one of the most intensive treatments of lymphoma, to the authors' knowledge has not been evaluated in the treatment of MLP. METHODS: Four consecutive patients with MLP were treated with high dose radiochemotherapy and ASCT while they were in partial response after conventional chemotherapy. RESULTS: Three patients achieved a complete clinical and histologic response and one achieved a complete clinical resolution of symptoms, but with persistent histologic lesions. Progression free survival ranged from 11 to 35 months. CONCLUSIONS: Autologous stem cell transplantation for patients with MLP is feasible and may be more effective than conventional chemotherapy. However, further studies are needed to assess the actual place of this type of treatment in the management of MLP.

Adult↗
PubMed1995

Differential expression of two siderophore-dependent iron-acquisition pathways in Erwinia chrysanthemi 3937: characterization of a novel ferrisiderophore permease of the ABC transporter family.

In planta expression of a high-affinity iron-uptake system involving the siderophore chrysobactin in Erwinia chrysanthemi 3937 contributes greatly to invasive growth of this pathogen on its natural host, African violets. A previous study reported that global regulation by iron in this strain was mediated at the transcriptional level via the cbr locus which, when inactivated by insertional mutation, prevents the chrysobactin system from being tightly repressed by FeCl3. Herein, we report the nucleotide sequence of this locus and the functional analysis of its encoded products. Sequence analysis of a 4.8 kb genomic segment of a plasmid encompassing the cbr locus and characterization of the cognate translated products made it possible to uncover a system exhibiting similarity with prokaryotic transporters implicated in the transport of iron complexes. Accordingly, the CbrA product was shown to be the periplasmic component of a permease complex also including two integral membrane proteins, CbrB and CbrC, and the ATP-binding unit CbrD. This system allowed internalization of Fe(III) when supplied to bacterial cells as 59FeCl3 or 59Fe dicitrate, via complexation to a second siderophore recently detected in strain 3937. Most notably, we demonstrate that this second siderophore-mediated iron-acquisition system is operational in bacterial cells grown in the presence of FeCl3. The regulatory effect of cbr was further assessed on a lacZ chrysobactin operon fusion indicating that the transcriptional control exerted by cbr on expression of the chrysobactin system is of homeostatic nature. in conclusion, E. chrysanthemi provides an interesting model in which iron acquisition involves an inductive process resulting in differential expression of two siderophore-mediated pathways in relation to external iron accessibility.

ATP-Binding Cassette Transporters↗
PubMed1994

Administration of granulocyte colony-stimulating factor from day 7 after autologous bone marrow transplantation: effects on neutropenia and duration of hospitalization.

G-CSF (5 mg/kg/day Filgrastim) was administered from day 7 after autologous bone marrow transplantation (ABMT) in a series of 17 patients treated for multiple myeloma or non-Hodgkin's lymphoma. In comparison with retrospective controls receiving ABMT without G-CSF and matched for age, underlying disease, disease status at ABMT, number of CFU-GM/kg reinfused, conditioning regimen and number and type of chemotherapy courses prior to ABMT, the duration of neutropenia, intravenous antibiotics and hospitalization was significantly reduced in the G-CSF group (p < 0.001). Delaying the administration of G-CSF after ABMT is an interesting possibility which merits further exploration in prospective randomized studies.

Adult↗
PubMed1994

Autologous bone marrow transplantation using TBI and CBV for disseminated high/intermediate grade cutaneous non-epidermotropic non-Hodgkin's lymphoma.

Patients with stage IV high/intermediate grade cutaneous non-epidermotropic lymphoma of skin as first localization of the disease have a poor prognosis. In this setting, autologous bone marrow transplantation (BMT) has rarely been evaluated. We report here on the treatment of four patients with such lymphomas with autologous BMT using 12 Gy total body irradiation (TBI) and CBV (cyclophosphamide, carmustine and etoposide). Using a plexiglass screen, TBI delivered an homogenized dose to the skin. With this conditioning regimen, all patients are still in complete remission 22, 44, 46 and 51, respectively, months after high-dose chemotherapy, TBI and autologous BMT.

Adult↗
PubMed1994

Isolated Richter's syndrome of the brain: two recent cases.

Two new cases of central nervous system (CNS) large cell lymphoma without evidence of systemic lymphoma in patients with chronic lymphocytic leukaemia (CLL) are reported. This unusual presentation of Richter's syndrome emphasizes the necessity to evoke this diagnosis in the case of neurologic symptoms in CLL.

Aged↗
PubMed1993

Localized invasive pulmonary aspergillosis in patients with neutropenia. Effectiveness of surgical resection.

BACKGROUND: Invasive pulmonary aspergillosis (IPA) is a major cause of morbidity and mortality in patients with neutropenia. Two severe complications with poor outcome can be observed after apparently successful IPA medical treatment: severe hemoptysis and IPA relapse during subsequent cytotoxic treatments. Early surgical therapy has not been considered routinely in the management of localized IPA. METHODS: Six consecutive patients (four women, two men; median age, 52 years) with localized cavitating IPA diagnosed during chemotherapy-induced aplasia were treated with early surgical resection after hematologic recovery. RESULTS: All patients received a lobectomy. Surgery was uneventful. This procedures allows patients to proceed with further intensive chemotherapy and/or bone marrow transplantation without IPA reactivation. CONCLUSIONS: For selected patients, surgical resection of localized IPA with unique cavitating lesion, which prevents hemoptysis and IPA recurrence and allows for subsequent cytotoxic treatment, may be recommended.

Adult↗
PubMed1993

Specificity of T cells invading the skin during acute graft-vs.-host disease after semiallogeneic bone marrow transplantation.

The mechanisms responsible for skin lesions during acute graft-vs.-host disease (aGVHD) after allogeneic bone marrow transplantation (BMT) are poorly understood. The exact role of various effector cell populations and "major" (particularly HLA-DP) or "minor" antigens as target molecules is not known. To investigate the nature of cells responsible for tissue injury, we cultured T cells from skin biopsy first with interleukin 2 (IL-2) alone and then in polyclonal activation conditions to avoid in vitro antigenic sensitization before specificity testing. We applied this method to two biopsies performed during aGVHD after semiallogeneic BMT and obtained cytotoxic T cells against four graft mismatches: CD8+ T cells against HLA-A2.2 and HLA-B27 and CD4+ T cells against HLA-DP101 and HLA-DP401. This demonstrates that T cells with documented specificity can be obtained from an aGVHD lesion without antigenic selection. Moreover, these data directly implicate DP as a potential target antigen for aGVHD.

Adult↗