Search PubMed⌕ Search

Biomedical subjects

N Philippe

Publications and source records attributed to N Philippe.

At least 55 records · Page 3Linked to original sources
PubMed1996

Differential expression of cell proliferation regulatory proteins in B- and T-lineage acute lymphoblastic leukaemias.

In order to better understand the molecular background of differences between the clinical picture of T- and B-lineage ALLs, we studied the expression of several proteins involved in the regulation of cell proliferation in bone marrow blast cells from 30 cases of previously untreated acute lymphoblastic leukaemia (ALL); 14 cases were T- and 16 B-cell lineage ALLs. We studied several cyclin-dependent kinases (cdk1, cdk2, cdk4, cdk6) and cyclins (cyclin A, cyclin B1, cyclin D3 and cyclin E). We also studied proliferating cell nuclear antigen (PCNA) and Bcl-2 expression, the latter protein known to be involved in the prolonged survival of B-lineage ALL blasts. Proteins obtained from cell lysates were resolved on polyacrylamide gel followed by immunodetection and densitometry of specific bands. Expression of cdk1 and PCNA, markers of proliferative activity, was significantly higher in T- than in B-lineage ALL. Cdk6, which was highly correlated to PCNA, was also higher in T-cell ALL. In contrast, B-lineage ALL displayed a higher expression of anti-apoptotic protein Bcl-2. We hypothesize that those particularities may reflect differential roles of cell multiplication and apoptosis in the neoplastic proliferation of B- and T-lineage ALL.

Adult↗
PubMed1996

Strong increase in the percentage of the CD8bright+ CD28- T-cells and delayed engraftment associated with cyclosporine-induced autologous GVHD.

Four children with acute lymphoblastic leukaemia had autologous bone marrow (BM) or peripheral stem cell (PSC) transplantation with low dose of cyclosporine (CsA, img/kg/d i.v. during the first 28 d) to induce an autologous GVHD (auto-GVHD). Two children did not have clinical auto-GVHD and they relapsed 3 and 4 months after treatment. The 2 other children had clinical signs of auto-GVHD (grade I and grade II); they both are in complete remission but after a first normal haematological recovery they had a prolonged period of aplasia until month 9 for 1 patient and still persistent at month 7 in the other case. We studied lymphocyte subsets reconstitution after transplantation in these patients. All patients had an important decrease in the CD4/CD8 ratio related both to a strong decrease in the CD4+ cells and a strong increase in the CD8+ cells. Most of the CD8+ cells were of the CD8bright+ CD28- phenotype. These CD8bright+ CD28- T-cells represented from 33% to 68% of the total lymphocytes. We discuss the role of these cells after autologous transplantation with CsA, and wonder if these cells could mediate cytotoxicity. In conclusion, among 4 children who received autologous BM or PBC transplantation with low dose of CsA, we observed a complete remission after an auto-GVHD and a prolonged period of aplasia in 2 patients and a relapse of leukaemia in 2 other patients. All these 4 patients had an increase in the CD8bright+ CD28- T lymphocytes.

Autoimmune Diseases↗
PubMed1996

Juvenile myelomonocytic leukemia: analyses of treatment results in the EORTC Children's Leukemia Cooperative Group (CLCG).

Forty-six children with juvenile myelomonocytic leukemia (JMML) diagnosed between 1978 and 1993 in 12 centers were retrospectively studied. There is no evidence that any conventional treatment influences the long-term evolution of JMML. Among 28 patients treated without bone marrow transplantation (BMT), 26 died (median survival: 17 months), two are alive, one in complete remission (CR) after intensive chemotherapy. Allogenic BMT is the best treatment: 18 patients underwent BMT, 11 are in CR (at 9, 15, 22, 25, 41, 45, 49, 53, 66, 90 and 108 months). Conditioning regimens using chemotherapy alone may cure some patients (3/6) occasionally despite autologous reconstitution (1/3); if relapse occurs, a second BMT may be curative (2/3). Among the 12 patients conditioned immediately with TBI, six are in CR, one is in relapse, five died (one of them in durable autologus CR from Schwannoma). It is our opinion that splenectomy is of therapeutic value and seems not to have influenced the incidence of infections complications. We found no argument in favor of intensive chemotherapy before conditioning. Results with HLA-matched unrelated donors are satisfactory. One patient relapsed at 4 months after an unrelated BMT and entered a new CR after discontinuation of cyclosporine.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Receptor-mediated internalization of insulin. Potential role of pp120/HA4, a substrate of the insulin receptor kinase.

pp120/HA4 is a hepatocyte membrane glycoprotein phosphorylated by the insulin receptor tyrosine kinase. In this study, we have investigated the role of pp120/HA4 in insulin action. Transfection of antisense pp120/HA4 cDNA in H35 hepatoma cells resulted in inhibition of pp120/HA4 expression and was associated with a 2-3-fold decrease in the rate of insulin internalization. Furthermore, insulin internalization in NIH 3T3 fibroblasts co-transfected with insulin receptors and pp120/HA4 was increased 2-fold compared with cells expressing insulin receptors alone. In contrast, no effect on internalization was observed in cells overexpressing a naturally occurring splice variant of pp120/HA4 that lacks the phosphorylation sites in the intracellular domain. Insulin internalization was also unaffected in cells expressing three site-directed mutants of pp120/HA4 in which the sites of phosphorylation by the insulin receptor kinase had been removed (Y488F, Y488F/Y513F, and S503A). Our data suggest that pp120/HA4 is part of a complex of proteins required for receptor-mediated internalization of insulin. It is possible that this function is regulated by insulin-induced phosphorylation of the intracellular domain of pp120/HA4.

3T3 Cells↗
PubMed1995

Insulin-stimulated phosphorylation of recombinant pp120/HA4, an endogenous substrate of the insulin receptor tyrosine kinase.

Insulin binding to the alpha-subunit of its receptor stimulates the receptor tyrosine kinase to phosphorylate the beta-subunit and several endogenous protein substrates, including pp120/HA4, a liver-specific plasma membrane glycoprotein of M(r) 20,000. Analysis of the deduced amino acid sequence of rat liver pp120/HA4 revealed two potential sites for tyrosine phosphorylation in the cytoplasmic domain (Tyr488 and Tyr513), as well as a potential cAMP-dependent protein kinase phosphorylation site (Ser503). To determine which of these sites is phosphorylated in response to insulin, each of these amino acid residues was altered by site-directed mutagenesis. Mutant cDNAs were then expressed by stable transfection in NIH 3T3 cells. Two mutations (Phe488 and Ala503) impaired insulin-induced phosphorylation of pp120/HA4, suggesting that pp120/HA4 undergoes multisite phosphorylation. It seems likely that Tyr488 is phosphorylated by the insulin receptor kinase, and phosphorylation of Ser513 may contribute to the regulation of tyrosine phosphorylation. Since pp120/HA4 is believed to be associated with a Ca2+/Mg(2+)-dependent ecto-ATPase activity, we determined the effects of insulin-induced phosphorylation on this enzymatic activity. In NIH 3T3 cells co-expressing the insulin receptor and pp120/HA4, insulin caused a 2-fold increase in ecto-ATPase activity. Moreover, elimination of the phosphorylation sites of pp120/HA4 impaired the ability of insulin to stimulate the ecto-ATPase activity. These data suggest that tyrosine phosphorylation of pp120/HA4 may regulate Ca2+/Mg(2+)-dependent ecto-ATPase activity.

3T3 Cells↗
PubMed1995

p16 gene homozygous deletions in acute lymphoblastic leukemia.

The p16 protein is a cyclin inhibitor encoded by a gene located in 9p21, which may have antioncogenic properties, and is inactivated by homozygous p16 gene deletion or, less often, point mutation in several types of solid tumors often associated to cytogenetic evidence of 9p21 deletion. We looked for homozygous deletion and point mutation of the p16 gene in acute lymphoblastic leukemia (ALL), where 9p21 deletion or rearrangement are also nonrandom cytogenetic findings. Other hematologic malignancies including acute myeloid leukemia (AML), myelodysplastic syndromes (MDS), chronic lymphocytic leukemia (CLL), and myeloma were also studied. Homozygous deletion of the p16 gene was seen in 9 of the 63 (14%) ALL analyzed, including 6/39 precursor B-ALL, 3/12 T-ALL, and 0/12 Burkitt's ALL. Three of the 7 ALL with 9p rearrangement (including 3 of the 5 patients where this rearrangement was clearly associated to 9p21 monosomy) had homozygous deletion compared to 5 of the 55 patients with normal 9p (the last patient with homozygous deletion was not successfully karyotyped). Single stranded conformation polymorphism analysis of exons 1 and 2 of the p16 gene was performed in 88 cases of ALL, including the 63 patients analyzed by Southern blot. Twenty-six of the cases had 9p rearrangement, associated to 9p21 monosomy in at least 12 cases. A missense point mutation, at codon 49 (nucleotide 164), was seen in only 1 of the 88 patients. No homozygous deletion and no point mutation of the p16 gene was seen in AML, MDS, CLL, and myeloma. Homozygous deletion of interferon alpha genes (situated close to p16 gene in 9p21) was seen in only 3 of the 9 ALL patients with p16 gene homozygous deletion, and none of the ALL without p16 gene homozygous deletion. Our findings suggest that homozygous deletion of the p16 gene is seen in about 15% of ALL cases, is not restricted to cases with cytogenetically detectable 9p deletion, and could have a pathogenetic role in this malignancy. On the other hand, p16 point mutations are very rare in ALL, and we found no p16 homozygous deletions or mutations in the other hematologic malignancies studied.

Base Sequence↗
PubMed1995

Allogenic BMT in children: differential lymphocyte subset reconstitution according to the occurrence of acute GVHD.

To acquire some biological markers associated with the occurrence of acute graft-versus-host disease (aGVHD) after allogeneic bone marrow transplant (BMT) in children, we have studied the lymphocyte subset reconstitution and the percentage of peripheral blood mononuclear cells bearing HLA-DR and HLA-DQ class II molecules. This study included 37 allogeneic BMT: either with (n = 17) or without (n = 20) aGVHD. Within 2 months after transplantation, we observed that patients with aGVHD had a unique mononuclear cell profile characterized by (i) a significant increase in the percentages of CD8bright+CD28- T cells (P = 0.05) and CD3+ T cells (P = 0.001), (ii) an important decrease in the percentage of CD56+ cells (P = 0.0001), and (iii) a decrease in the percentages of HLA-DQ+ and HLA-DR+ monocytes (P = 0.001) and HLA-DQ+ T lymphocytes (P = 0.0001), in comparison with patients without aGVHD. Moreover, statistical studies indicate that there was a positive correlation between CD8bright+CD28- and CD3+ T cells, whereas CD3+ T cells were negatively correlated to CD56+ cells. We did not find any statistical correlation between the percentages of HLA-DQ+ or HLA-DR+ cells and the percentages of these lymphocyte subsets. Therefore, in this study done in children, we suggest that patients with (i) less than 20% of DQ+ monocytes, (ii) less than 25% of CD56+ lymphocytes, and (iii) an enhanced percentage of CD8bright+CD28- T cells are strongly associated with aGVHD. Unfortunately, these biological markers of a GVHD may not precede the clinical manifestations of the disease.

Acute Disease↗
PubMed1995

[Transient erythroblastopenia in early childhood].

BACKGROUND: Transient erythroblastopenia is rare in young children although its frequency is increasing. POPULATION AND RESULTS: Six infants (four boys, two girls), aged 29-41 months (mean: 33) were admitted for polar and asthenia. Only one displayed infectious episode two months earlier. Hemoglobin ranged from 40 to 67 g/l and reticulocyte number from 1 to 10 G/l. Mean corpuscular volume was normal as was Coombs' test. There was a profound erythroblastopenia in the bone marrow in five of the six patients. Parvovirus B19 infection was excluded in all. The white cell and platelet counts were normal. All patients were given an unique blood transfusion. Reticulocytosis spontaneously appeared within a few weeks in three patients. Another patient had normal number of erythroid precursors in the bone marrow 1 month after admission. CONCLUSION: Diagnosis of transient erythroblastopenia can only be made after exclusion of known causes such as drugs, virus, immune deficiency, leukemia and of Blackfan-Diamond disease. Its persistence must lead to search for another cause.

Age Factors↗
PubMed1995

Analysis of p16 gene deletion and point mutation in breast carcinoma.

We looked for p16 gene deletion by Southern analysis and p16 gene point mutation by single-stranded conformation polymorphism (SSCP) analysis and direct sequencing of DNA from fresh tumour samples of 35 and 33 breast carcinomas respectively. No homozygous p16 gene deletion was found in any case. A missense point mutation of the p16 gene was found in only one patient. This point mutation was absent from the patient's lymphocytes, ruling out a polymorphism or a germline mutation. These findings suggest that p16 gene alterations are rarely observed in breast carcinoma.

Base Sequence↗
PubMed1995

A new alpha chain variant Hb Sallanches [alpha 2 104(G11) Cys-->Tyr] associated with HbH disease in one homozygous patient.

We identified a new alpha-chain variant (alpha Sal) associated with haemolytic anaemia and low level of HbH in one homozygous patient. This new mutation is located in codon 104 (TGC-->TAC) of the alpha 2 globin gene and results in a Cys-->Tyr replacement. In vitro and in vivo biosynthetic studies suggest that the mechanism leading to HbH disease in this homozygous patient is mostly related to a significant instability of alpha Sal:beta dimers rather than to the hyperinstability of the alpha Sal chain itself only.

Adult↗
PubMed1995

Proliferation of MIELIKI a novel t(7;9) early pre-B acute lymphoblastic leukemia cell line is inhibited concomitantly by IL-4 and IL-7.

The present study describes a novel cell line, MIELIKI, established from bone marrow of a pediatric patient with B lineage acute lymphoblastic leukemia (ALL) at diagnosis. The MIELIKI cell line displays an early pre-B cell phenotype (CD10+, CD19+, CD20+, CD34-, Cmu-, sIg-) with rearrangements on both Ig heavy chain and k light chain alleles, and carries an unfrequent t(7;9) chromosomal translocation identical to the freshly isolated leukemic blasts. The proliferation of MIELIKI cells was abrogated by IL-4 and by IL-7, as measured by DNA replication and viable cell recovery. The effects of IL-4 and IL-7 were mediated, respectively, through the CDw124 and CDw127 IL-4 and IL-7 receptor components. Growth inhibition by IL-4 was not mediated by soluble factors released by MIELIKI cells in response to IL-4, suggesting the existence of an intrinsic negative signaling pathway. Finally, neither IL-4 nor IL-7 were found to induce maturation of MIELIKI into cells expressing cytoplasmic or surface membrane mu chain. The present cell line should constitute a useful model of t(7;9) early pre-B ALL and allow investigation of the relationship between IL-4 and IL-7 negative signaling in leukemic B cell ontogeny.

Antigens, CD↗
PubMed1995

Molecular study of Glanzmann thrombasthenia in 3 patients issued from 2 different families.

In an effort to further understand Glanzmann thrombasthenia (GT) 3 patients from 2 different families were studied. After biochemical and immunological analysis these patients were classified as type I. We observed in the first family a new restriction site for Stu I in exon II of the glycoprotein (GP) IIIa gene caused by a homozygous nonsense mutation: 62 Arg to stop codon. The parents were heterozygotes for this mutation. We found in the second family a previously described nonsense mutation: 584 Arg to stop codon in exon 17 of the GPIIb gene. The father and his two affected sons were heterozygous for this genetic defect. This mutation 62 Arg to stop codon is a new description of a genetic defect associated with GT. Furthermore, the discovery of the same mutation in 3 affected families from different ethnic groups raises the possibility of either a hot spot mutation in the CG dinucleotide region of GPIIb gene, or an ancient mutant allele present in diffuse populations at a relatively high frequency.

Amino Acid Sequence↗
PubMed1994

Partial albinism with immunodeficiency (Griscelli syndrome).

Partial albinism with immunodeficiency is a rare and fatal immunologic disorder characterized by pigmentary dilution and variable cellular immunodeficiency. To define the phenotype, therapy, and outcome, we retrospectively analyzed seven consecutive patients. Primary abnormalities included a silvery-grayish sheen to the hair, large pigment agglomerations in hair shafts, and an abundance of mature melanosomes in melanocytes, with reduced pigmentation of adjacent keratinocytes. Clinical onset occurred between the ages of 4 months and 4 years and was characterized by accelerated phases (lymphohistiocytic infiltration of multiple organs, including the brain and the meninges), triggered by viral and bacterial infections. Characteristic laboratory features included pancytopenia, hypofibrinogenemia, hypertriglyceridemia, and hypoproteinemia. Consistent immunologic abnormalities were characterized by absent delayed-type cutaneous hypersensitivity and impaired natural killer cell function. Some patients had secondary hypogammaglobulinemia, impaired major histocompatibility complex-mediated cytotoxic effects, a decreased capacity of lymphocytes to trigger a mixed lymphocyte reaction, or various functional granulocytic abnormalities. The disease seems to be invariably lethal without bone marrow transplantation; the mean age at the time of death was 5 years. Bone marrow transplantation has been performed in three cases; two patients died in the immediate posttransplantation period of infectious complications, but one patient is cured after a follow-up of 5 years. We conclude that partial albinism with immunodeficiency (Griscelli syndrome) can be differentiated from Chédiak-Higashi syndrome by pathognomonic histologic features. One of the underlying immunologic defects may be a defective function of natural killer cells, predisposing the patient to virus-associated hemophagocytic syndrome or accelerated phases. The prognosis is very poor unless early bone marrow transplantation is carried out.

Adrenal Cortex Hormones↗
PubMed1994

A high percentage of HLA-DQ+ and HLA-DR+ mononuclear cells is associated with a low incidence of acute graft-versus-host disease after allogeneic bone marrow transplantation (BMT) in children.

In order to discover some biological markers of acute graft-versus-host disease (aGVHD), we have studied the percentage of peripheral monocytes and T lymphocytes bearing HLA-DR and HLA-DQ class II molecules. This study included 25 allogeneic BMT in children, either with (n = 10) or without (n = 15) aGVHD. Within 2 months after transplantation, a higher percentage of DQ+ and DR+ monocytes and of DQ+ T lymphocytes was observed in patients without aGVHD compared with patients with aGVHD. The most discriminating marker was the strong increase in the percentage of DQ+ monocytes in patients without aGVHD (P = 0.001). In a sequential study, we observed a low percentage of DQ+ and DR+ peripheral blood mononuclear cells (PBMC) as long as the clinical manifestations of aGVHD continued. We speculate if the modulation of DQ and DR molecules on PBMC after BMT is a consequence of the action of some lymphokines, and if it plays a role in the regulation of the acute GVH reaction. We conclude that MHC class II molecules on peripheral mononuclear cells may be reliable biological markers for the diagnosis of aGVHD.

Acute Disease↗
PubMed1994

A phase II study of recombinant human granulocyte-colony stimulating factor (rHuG-CSF, lenograstim) in the treatment of agranulocytosis in children.

The present study evaluated the clinical efficacity and tolerability of the subcutaneous (SC) administration of lenograstim, a glycosylated form of rHuG-CSF identical to human G-CSF, in the treatment of congenital agranulocytosis. Assessment criteria included neutrophil response and response stability, incidence and severity of infection and gingivostomatitis and quality of life. Lenograstim, at induction dosages of 5 (n = 9), 10 (n = 2) or 20 (n = 1) microgram/kg/day SC, produced neutrophil recovery in all of 12 children with congenital agranulocytosis. There was a median delay of 7 days to recovery after establishment of the effective induction dose. Whereas this dosage maintained a stable neutrophil response in 7 patients, the remaining 5 required dosage increases and dose reduction during maintenance therapy was not possible in these 5 cases. Among 4 patients stabilised at a dosage of 5 micrograms/kg/day, in 2 cases a lower minimum effective dose of 2 micrograms/kg/day was attained over the maintenance phase. Administration of twice the daily dose of lenograstim on alternate days was feasible in 3 of 8 patients. Lenograstim therapy reduced the incidence of infection and hospitalisation for infection relative to the prestudy period, while in 6 of 9 cases there was complete recovery from gingivostomatitis. Only one patient discontinued treatment on account of adverse events. Finally, perceived health and disease related symptoms showed a significant (p < 0.001) amelioration in the course of the study. Thus, lenogastrim produced sustained neurotrophil recovery in patients with congenital agranulocytosis, decreased the incidence and severity of infection and improved the quality of life.

Adolescent↗