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Biomedical subjects

G Lenoir

Publications and source records attributed to G Lenoir.

At least 145 records · Page 8Linked to original sources
PubMed1989

Tumor-specific loss of 11p15.5 alleles in del11p13 Wilms tumor and in familial adrenocortical carcinoma.

We have compared constitutional and tumor genotypes in nine cases of hereditary Wilms tumor (WT) and in three unrelated cases of familial adrenocortical carcinoma (ADCC). Since susceptibility to these tumors can be observed in malformation syndromes associated with a constitutional deletion of band 11p13 (WT) and with a constitutional duplication of band 11p15.5 (WT, ADCC), we investigated these two candidate regions by using 11p polymorphic markers. As expected, somatic chromosomal events, resulting in a loss of heterozygosity limited to region 11p15.5, were observed in the tumor of two familial cases of adrenocortical carcinoma. Surprisingly, however, analysis of the WT of two patients with a constitutional deletion of band 11p13, associated with aniridia, genitourinary abnormalities, and mental retardation (WAGR syndrome), revealed a loss of heterozygosity limited to region 11p15.5. These data therefore suggest that observation of a specific loss of heterozygosity may not necessarily point to the site of the initial germinal mutation. Together with previous similar observations of a loss of heterozygosity limited to 11p15.5 in breast cancer and in rhabdomyosarcoma, our data suggest that region 11p15.5 may carry a non-tissue-specific gene that could be involved in genetic predisposition, in tumor progression, or in both.

Adrenal Cortex Neoplasms↗
PubMed1989

[Iron deficiency and Pseudomonas aeruginosa colonization in cystic fibrosis].

The incidence of iron deficiency and its relationship with the concentration or iron in sputum and the number of Pseudomonas aeruginosa (PA) colonies was studied in an unselected group of 53 cystic fibrosis (CF) patients with an age range of 3 months to 21 years. Parameters used to assess the iron status included serum iron, the % saturation of transferrin (n = 53). The number of subjects with depletion of iron stores was estimated by levels of ferritin (n = 50). The concentration of iron and of PA was measured in a subgroup (n = 24) and compared to a control group (n = 8) with pulmonary infections of varying etiology. A close correlation was found between serum iron and the % saturation of transferrin (r = 0.952; p less than 0.001). Between 22.6 to 28.3% of patients were found to be iron deficient. An abnormally low ferritin (less than 12 ng/ml) was noted in 28% of cases but no correlation could be established between changes of serum iron and ferritin levels as a function of the degree of infection and/or of inflammation. In 62% of cases (n = 15) the concentration of iron in sputum was found to be within the range of control values (12-27 mumols/l). In 38% of cases (n = 9), ferritin values were above 27 mumols/l. No correlation was found between the concentration of iron and the number of PA colonies in sputum. We can therefore conclude the following: 1) iron deficiency is more common in CF than previously reported; 2) ferritin levels constitute a poor index of iron deficiency; 3) colonisation with PA is not associated with iron content of bronchial secretions.

Adolescent↗
PubMed1989

Phenotypic analysis of human myeloma cell lines.

Multiple myeloma (MM) is a B-cell malignancy characterized by the accumulation, primarily in bone marrow, of a clone of plasma cells. The nature of the stem cells feeding the tumoral compartment is still unknown. To investigate this special point, we have studied the phenotypes of nine well-known human myeloma cell lines (HMCLs) and compared them with those of normal lymphoblastoid cell lines (LCLs). Twenty-four clusters of differentiation involved in B lymphopoiesis were investigated using a panel of 65 monoclonal antibodies (MoAbs). For each cluster, the percentage of positive cells and the antigen density were determined, giving rise to a "quantitative phenotype". We thus classified the HMCLs into two different groups: those with cytoplasmic mu chains (c mu+) and those without (c mu-). In the first (c mu+) group, comprising seven cell lines, the HMCLs had a phenotype of pre-B/B cells close to that of Burkitt's lymphoma cell lines. They expressed low densities of surface mu chains, without detectable cytoplasmic or surface light chains. Three of them were infected with the Epstein Barr virus (EBV). These c mu+ HMCLs bore most of the B-cell antigens except CD23. They expressed the CALLA antigen (CD10) and lacked the plasma-cell antigen PCA1. In contrast, LCLs expressed surface light chains, high densities of CD23, low densities of PCA1 antigen, and no CD10 antigen. The c mu- HMCLs had a plasma-cell phenotype, lacking most of the B-cell antigens and expressing high densities of PCA1 antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Differentiation, B-Lymphocyte↗
PubMed1989

Epstein-Barr virus associated lymphoproliferative diseases (B cell lymphoma) after transplantation.

We report 12 cases of lymphomas which occurred among 1670 patients with kidney or combined renal and pancreatic transplantation. Group 1 comprised nine patients presenting with the diffuse form of the disease where immunoblasts or mature plasma cells massively infiltrated all organs. The first symptom was a viral syndrome, associated with a restriction of heterogeneity of immunoglobulins; oligoclonal to monoclonal peaks of immunoglobulins appeared about 50 days after transplantation. All patients received antilymphocyte globulins (ALG), and seven were treated with cyclosporin. EBV infection could be demonstrated in almost all patients; three EBV lymphoblastoid cell lines were established, their HLA phenotype being the same as the recipient of the graft. All patients finally died with renal and hepatic failure. Group 2 comprises three patients who presented solid B cell tumours of tonsils, lungs, and spleen at onset, extending to liver, kidney graft, lymph nodes, and brain. All received cyclosporin; two patients were treated with ALG, and one with OKT3. Immunoglobulins were polyclonal, oligoclonal, or decreased. Cell surface immunoglobulins were monoclonal on two tumours. EBV-DNA was positive within two tumours. Two patients presented EBV and CMV primary infection. CD4+T lymphocytes subsets were diminished at onset, and increased after cessation of immunosuppressive therapy. One patient died because of brain involvement; the two others are alive, one with perfect graft function. Therapy consisted of stopping immunosuppressive treatment, Acyclovir, and in two patients of group 2, monoclonal antibodies to pan-B and EBV receptor antigens.

Acyclovir↗
PubMed1989

[Immunodeficiency and cancer].

The analysis of cancers associated with immunodeficiencies (either congenital, iatrogenic or acquired) enabled us to define the possible role of these deficiencies in the sequence of events leading to cancer and in particular the emergence of hematopoietic proliferations. Immunodeficiency increases the risk of viral infection, and in severe deficiencies, uncontrolled infections (Epstein-Barr virus) are directly responsible for the appearance of polyclonal proliferations; in moderately severe deficiencies, the hyperstimulation of the immune system by repeated infections increases the number of mutagenic events, but the immortalization of a malignant clone is a late event, which may or may not be linked to a viral infection. On the other hand, some intrinsic congenital or acquired abnormalities of lymphoid cells may be responsible both for immunodeficiency and carcinogenesis (chromosomic fragility). Apart from any immunological reaction, the immune system plays a role in the proliferation and differentiation events in various tissues; and any dysregulation of the latter may indicate the emergence of a cancer.

Acquired Immunodeficiency Syndrome↗
PubMed1989

[Joint tolerance of pefloxacin and ofloxacin in children and adolescents with cystic fibrosis].

Retrospective analysis of 63 patients with mucoviscidosis (age: 11 to 21 years), treated with pefloxacine, shows the occurrence of arthropathies ascribed to pefloxacine in 9 patients (age: 9 to 20 years), or 14% of the patients under treatment. The dose of pefloxacine was normal (9 to 16 mg/kg/day) in all cases, except one case of overdose (29 mg/kg/day). Mechanical arthralgias, affect the knees, elbows and wrists, resulting in functional discomfort, and frequently accompanied by mechanical synovial extravasation. They always subside after pefloxacine is discontinued. The role of age is essential as the incidence of arthropathies reaches 45% when pefloxacine is first administered between the ages of 15 and 20 years. Retrospective analysis of 37 patients with mucoviscidosis (age: 2 to 20 years), treated with ofloxacine, failed to show any joint complication. In this study, the best joint tolerance of ofloxacine, compared with pefloxacine is statistically significant. Arthropathies induced by pefloxacine represent an original entity which seems related to the cartilage toxicity of quinolones, observed in animal experiments, during growth.

Adolescent↗
PubMed1988

[Pharmacokinetics of ceftazidime in cystic fibrosis].

Ceftazidime has been recognized as an invaluable antibiotic for the treatment of lower respiratory infections in patients with cystic fibrosis. In these patients the apparent volume of distribution of ceftazidime is increased. Its clearance is besides increased, with a significant reduction in the area under concentrations curve. The distribution of ceftazidime in the bronchi seems to be very satisfactory. It results from these data that dosage in children with cystic fibrosis may reach 200 to 300 mg/kg/day divided into 3 or 4 injections. The intrabronchial administration of ceftazidime has not proved effective.

Bronchi↗
PubMed1988

Cytogenetic evaluation of bone marrow involvement in Burkitt's lymphoma.

Twenty-six bone marrow samples from 21 patients with Burkitt's lymphoma were examined cytogenetically after short-term culture. Clonal chromosomal changes were detected in one of 18 samples from morphologically normal marrows, and in three out of six samples with verified tumor invasion. Three patients had the translocation (8;14)(q24;q32) and one had t(2;8)(p12;q24). Two samples with suspect tumor involvement (less than 5% putative tumor cells) showed no clonal abnormalities. In two samples without morphologic bone marrow infiltration and with only normal metaphases in short-term cultures, clones with t(8;14)(q24;q32) were revealed after a longer time (3-12 weeks) spent in vitro.

Adolescent↗
PubMed1988

6q1 monosomy: a distinctive syndrome.

A female infant with a de novo del 6q14q16.2 and five other patients with del 6q1 reported in the literature allow the delineation of a characteristic syndrome, the main features of which are: severe mental retardation, a round face with full cheeks, upslanting palpebral fissures, a short neck, umbilical hernia, malpositioned feet with syndactyly II-III, and typical dermatoglyphics with an excess of whorls and clinodactyly of the Vth finger.

Abnormalities, Multiple↗
PubMed1988

Treatment of severe Epstein-Barr virus-induced polyclonal B-lymphocyte proliferation by anti-B-cell monoclonal antibodies. Two cases after HLA-mismatched bone marrow transplantation.

We treated two children who developed Epstein-Barr virus-induced polyclonal B-cell proliferation after HLA-mismatched bone marrow transplantation for congenital immunodeficiency with two monoclonal anti-B-cell antibodies. Lymphoproliferative syndrome occurred between 50 and 60 days after bone marrow infusion, and was diagnosed by the presence of spontaneously growing B cells containing Epstein-Barr-nuclear antigen in the blood and bone marrow. The mouse monoclonal anti-B-cell antibodies used were a CD21-specific antibody recognizing the CR2 receptor on B cells (BL13, IgG1) and a CD24-specific antibody binding B cells at all steps of differentiation (ALB9 IgG1). Both antibodies were given intravenously (0.2 mg/kg/body weight.d for 10 days). All clinical and biological manifestations resolved within 3 weeks of treatment. Recurrence was not seen at 18- and 15-month follow-ups. T-cell function developed normally; B-cell function remained partially deficient in one patient 21 months after bone marrow transplantation. These results suggest that monoclonal anti-B-cell antibodies could be useful in controlling severe polyclonal lymphoproliferative syndrome in profoundly immunodeficient patients after bone marrow transplantation.

Antibodies, Monoclonal↗
PubMed1988

[Removal of prednisone and prednisolone during plasma exchange].

Prednisone and prednisolone extraction was determined during seven sessions of plasma exchange in four patients. Each patient received 0.5 mg/kg of prednisone administered orally 2 hours before plasma exchange. Concentrations of prednisone and prednisolone were determined in blood before, every half hour during and at the end of plasma exchange. Both drugs were also determined in removed plasma, mean volume of removed plasma being 0.96 plasmatic mass. The amount of combined prednisone and prednisolone removed by plasma exchange was 1.70% of the administered prednisone dose. This quantity appears minimal and supplemental dosing of prednisone or modification of administration time would seem to be unnecessary.

Chromatography, High Pressure Liquid↗
PubMed1987

Paired Epstein-Barr virus (EBV)-negative and EBV-converted Burkitt lymphoma lines: stimulatory capacity in allogeneic mixed lymphocyte cultures.

Epstein-Barr virus (EBV)-negative Burkitt lymphoma lines (BLE-) and their in vitro EBV-converted sublines (BLEc), obtained by infection with the P3HRI and B95-8 strains of EBV, were compared for their capacity to induce T-lymphocyte proliferation in allogeneic mixed lymphocyte cultures (MLC). Regardless of the virus strain used for conversion, the BLEc lines induced a considerably stronger primary MLC response than their EBV-negative parentals. Only the BLEc lines were able to maintain T-lymphocyte proliferation in repeated stimulations. The low proliferative response observed in cultures stimulated with BLE- cells was not due to the generation of suppressor cells or to the release of inhibitory factors. The increased stimulatory capacity of BLEc lines was unrelated to changes in expression of MHC class-I and class-II antigen, or of B-cell activation markers, and was not due to the reactivation of EBV-specific memory T cells, since lymphocytes from EBV-seropositive and seronegative donors responded similarly. The results indicate that the capacity of BL cells to elicit cellular immune responses may be influenced by their EBV-carrying status.

Antigens, Viral↗
PubMed1987

Effects of long-term maintenance therapy with a new glucocorticoid, deflazacort, on mineral metabolism and statural growth.

Deflazacort was substituted for Prednisone (based on the equivalence 1 mg Prednisone equals 1.2 mg Deflazacort), during maintenance glucocorticoid therapy in 9 children, 5 with renal diseases and 4 with connective tissue or immunoproliferative disorders. Six patients received 0.26-0.35 mg/kg body weight (B.W.)/day and 3 0.48-1.2 mg/kg B.W. on alternate days, for 10-16 months. Except for a child with chronic juvenile arthritis, who was also unresponsive to Prednisone, the therapeutic effects of Deflazacort were excellent. Steroid side effects present in 8 patients decreased or disappeared. Plasma Ca, P, Mg, creatinine, alkaline phosphatase, iPTH(1-34), urinary excretion of Ca, cAMP, and TRP remained normal. Plasma iPTH(1-84) remained normal in 5 children; in the other 4 patients it increased from normal to slightly elevated values. On Deflazacort, plasma calcidiol concentrations were within the normal range in 6/8 patients prescribed daily doses of vitamin D2 (1,600-2,400 IU) or calcidiol (20 micrograms). Plasma 1,25(OH)2D levels monitored in 5 children were also normal. The osteoporosis, evaluated on the tibial cortico-diaphyseal ratio and the trabecular aspect of bone radiograms, present in 5 patients, persisted in 1 and improved in the others. On Deflazacort, statural growth proceeded normally in all subjects, with a modest acceleration of growth velocity in 3 children. These results seem encouraging for extending clinical trials with Deflazacort to the active phase of pediatric diseases requiring glucocorticoid.

Adolescent↗