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Biomedical subjects

N Philippe

Publications and source records attributed to N Philippe.

At least 73 records · Page 4Linked to original sources
PubMed1994

[A rare cause of hyponatremia during introductory treatment of acute lymphoblastic leukemia in an infant: inappropriate secretion of atrial natriuretic factor?].

BACKGROUND: --Hyponatremia is frequently seen during the treatment of acute lymphoblastic leukemia: its causes are numerous. This work aims to present a case in whom hyponatremia was possibly due to an increased secretion of atrial natriuretic factor. CASE REPORT: --A 3 week-old baby was admitted because of malignant hemopathy. A diagnosis of acute lymphoblastic leukemia was rapidly made and the patient was firstly given alkaline diuresis, urate-oxidase and corticosteroids. Vincristine and daunorubicin were associated one week later. Insertion of a central intravenous line in the right subclavicular artery failed so that this catheter was finally inserted into the left jugular vein. Natremia was 126 mmol/l at that time and dramatically decreased within 24 hours to 109 mmol/l without net changes in water and electrolytic input. At that time, sodium urinary excretion was 6 mmol/kg/day (diuresis: 420 mlF/day). There was no hemodynamic changes, nor digestive or cardiac manifestations. Ultrasonography showed that the left superior cava vein drained into the right cardiac atrium. The catheter was withdrawn and the patient was given sodium supplementation permitting complete and definitive cure of hyponatremia within 2 days. CONCLUSIONS: --All usual causes of hyponatremia having been ruled out in this patient, we postulate that hyponatremia was due to direct stimulation of atrial natriuretic peptide through an increase in atrial pressure secondary to the catheter insertion near the cardiac atrium.

Atrial Natriuretic Factor↗
PubMed1993

Infusion of Fc gamma fragments for treatment of children with acute immune thrombocytopenic purpura.

Treatment of acute immune thrombocytopenic purpura (ITP) with intravenous immunoglobulin (IVIG) induces partial or complete responses, shown by transient or persistent increases in platelet count. The clinical benefit could be due to blockade of the Fc gamma receptor (Fc gamma R); platelets sensitised by IgG could not be cleared by cells of the reticuloendothelial system if Fc gamma R on these cells was blocked with IVIG. To find out whether this putative mechanism is correct, we treated twelve children who had acute ITP with intravenous infusions of Fc gamma fragments. Eleven children showed rapid increases in platelet counts to above the critical value of 50 x 10(9)/L, thereby avoiding major haemorrhagic risk. The response was stable in six patients and transient in five. No adverse reactions were observed. In responders who had detectable platelet-associated IgG before treatment (> 1500 IgG per platelet), platelet IgG fell substantially with treatment. Serum soluble CD16 (sCD16 or sFc gamma RIII) concentrations, measured in five children, showed transient or stable increases that correlated with the rise in platelet count. No sCD16 was detected in the Fc gamma preparation used. We conclude that the infusion of Fc gamma fragments is an efficient treatment of acute ITP in children. The efficacy of Fc gamma fragments strengthens the hypothesis that Fc gamma R blockade is the main mechanism of action of IVIG in ITP, although other immunoregulatory mechanisms triggered by the presence of increased sCD16 concentrations in serum could be involved in the clinical benefit observed.

Adolescent↗
PubMed1993

Increased thrombin generation in a child with a combined factor IX and protein C deficiency.

We report a quantitative protein C deficiency combined with a factor IX deficiency in a one-year-old boy. The inheritance of the two deficiency states was independent, the factor IX defect coming from the mother and the protein C defect from the father. Both factor IX activity and antigen were below 1%, and protein C activity as well as antigen were close to 27% of normal values. This association raises a real therapeutic and prognostic question. Protein C deficiency is indeed associated with a significant thrombotic risk and some factor IX concentrates seem to carry a potential thrombogenicity, particularly following infusion of repeated doses. We evaluated in this patient the potential activation of the coagulation system by measuring the levels of prothrombin fragment F1 + 2 at the basal state and after a single administration of 20 U/kg of a high purity factor IX concentrate. We found an unexpected basal activation of the hemostatic system before infusion (F1 + 2 = 1.6 nmol/L), which further increased during 8 hours. Despite the clinical predominant expression of the hemophilic trait, our results seem to assess the biologic prevalence of the protein C deficiency. This emphasizes the need for a careful follow-up after infusions of repeated doses of factor IX, as used during a surgical procedure. Furthermore, this raises the question of the prognosis because the risk of thrombotic manifestations associated with a protein C deficiency increases with age. Finally, these results highlight a part of the in vivo activation process of prothrombin in case of failure of the intrinsic pathway of coagulation. The protein C defect seems to be responsible for an upregulation of the prothrombin activation through the extrinsic pathway.

Factor IX↗
PubMed1993

pp120/ecto-ATPase, an endogenous substrate of the insulin receptor tyrosine kinase, is expressed as two variably spliced isoforms.

The insulin receptor possesses tyrosine kinase activity which is thought to mediate the biological effects of insulin upon target cells. pp120 is a liver-specific glycoprotein of apparent molecular size of 120 kDa that is phosphorylated on tyrosine residues by the receptors for insulin, insulin-like growth factor-I, and epidermal growth factor. Previously, we demonstrated that pp120 is identical to a liver-specific ecto-ATPase. In the present study, we have cloned the rat gene encoding pp120/ecto-ATPase. The gene is contained within approximately 15 kilobases of genomic DNA, and consists of nine exons interrupted by eight introns. Using the reverse transcriptase/polymerase chain reaction, we isolated cDNA clones complementary to rat liver mRNA encoding pp120/ecto-ATPase. Sequence analysis indicated the presence of two populations of cDNA's that differ by the presence or absence of a 53-base pair (bp) fragment encoding the juxta-membrane region of the cytoplasmic domain. By cloning the corresponding region of the ecto-ATPase gene, we demonstrated that the 53-bp represents exon 7 of the gene. This 53-bp exon undergoes alternative splicing, thereby giving rise to two mRNA variants. Deletion of this 53-bp cassette exon introduces a frameshift, and results in a premature chain termination codon that truncates the cytoplasmic domain. The truncated cytoplasmic domain contains 10 rather than 71 amino acid residues. Because the short isoform of ecto-ATPase lacks the putative sites for tyrosine- and serine-specific phosphorylation, this alternative splicing may have a major effect upon the physiological function of the enzyme.

Adenosine Triphosphatases↗
PubMed1993

Hepatic tumours during androgen therapy in Fanconi anaemia.

The occurrence of liver tumours in the course of Fanconi anaemia (FA) has been well documented. We present a case, review the literature and conclude that androgen therapy would increase the risk of developing tumours, most of which appear to be benign (adenomas or peliosis) and androgen-dependent, generally decreasing in size after cessation of treatment. Survival of patients is poor, mostly because of the rapid evolution of the tumour. In the absence of an allogenic bone marrow transplantation, administration of haematopoietic growth factors might be effective. As a preventive measure, other types of unsubstituted androgens may be used.

Adenoma↗
PubMed1993

Low expression allele alpha LELY of red cell spectrin is associated with mutations in exon 40 (alpha V/41 polymorphism) and intron 45 and with partial skipping of exon 46.

The alpha V/41 polymorphism of erythroid alpha-spectrin has been characterized initially by an increased susceptibility to proteolysis of the alpha IV-alpha V domain junction (Alloisio N., L. Morlé, J. Maréchal, A.-F. Roux, M.-T. Ducluzeau, D. Guetarni, B. Pothier, F. Baklouti, A. Ghanem, R. Kastally, et al. 1991. J. Clin. Invest. 87:2169-2177). Until now, it has been found associated invariably with a low expression level of the corresponding alpha chain. Among 61 chromosomes investigated in French and North African individuals or kindreds, we observed 19 chromosomes with the alpha V/41 polymorphism. With no single exception, the latter displayed a point mutation in exon 40 (Leu-->Val; CTA-->GTA) at position alpha 1857. According to the triple helical model of spectrin structure, this change accounts for the peptide maps' abnormalities. Sequencing the entire alpha V domain cDNA disclosed, in addition, a partial skipping of exon 46. At the gene level, a substitution (C-->T) was evidenced at nucleotide -12 of intron 45. This mutation appeared linked to the exon 40 mutation in 17 chromosomes, again with no single exception, among 53 examined chromosomes. We hypothesized that the lack of exon 46 would hamper the nucleation process and eventually account for the low expression feature. The present doubly mutated allele was renamed allele alpha LELY (low expression, Lyon).

Alleles↗
PubMed1993

[Langerhans cell histiocytosis associated with myasthenia in an infant].

The pathogenesis of Langerhans cell histiocytosis (LCH) is unclear, but there is increasing evidence that an immunological dysfunction is present. We describe an infant who presented a LCH associated with myasthenia gravis. The thymus is known to play an important role in the pathophysiology of myasthenia gravis and is often involved in LCH. Infancy and signs of organ dysfunction are predictive of poor prognosis: immunotherapy is to be investigated (thymic hormone, cyclosporin, alpha interferon), as well as allogeneic bone marrow transplantation.

Female↗
PubMed1993

[Psychological aspects of bone marrow donation in donor brothers and sisters in bone marrow transplantation].

It appears to be necessary to consider, during a bone marrow transplantation, brothers and sisters who are donors. These children face psychological difficulties, which are not always understood by medical staff and families who are mainly concerned with the health of the sick children. Systematic meetings with a hundred donors point out the distress experienced in these situations.

Bone Marrow Transplantation↗
PubMed1993

Characterization of a t(1;19) pre-B acute lymphoblastic leukemia (ALL) cell line which proliferates in response to IL-7.

The present study describes the establishment of the cell line Pre-Alp from the bone marrow of a pediatric patient with a t(1;19) pre-B acute lymphoblastic leukemia (ALL) at diagnosis. Proliferation of leukemic blasts was found to be initially dependent on the presence of autologous stromal cells. However, after five weeks of culture, the stromal cells were no longer necessary and cells began to grow autonomously, with a doubling time of approximately 24 hours. The established Pre-Alp cell line displays a pre-B cell phenotype (CD19+, CD10+, CD34-, c mu+, s mu-), with immunoglobulin (Ig) light chain DNA in germline configuration, and carries a (1;19)(p23;q13.3) chromosomal translocation identical to the freshly-isolated leukemic blasts. A unique feature of this cell line is represented by its ability to respond to interleukin 7 (IL-7). Thus, IL-7 enhances 3H-thymidine uptake by Pre-Alp cells in a dose-dependent manner, under conditions of low cell density and serum concentration, and increases cell recovery. Finally, Pre-Alp cells were found to remain at a pre-B stage even upon addition of various cytokines, which failed to induce a transition to surface Ig+ cells. The presently described cell line should constitute a useful model of t(1;19) pre-B ALL and permit the study of IL-7 dependent signal transduction in human pre-B cells.

Base Sequence↗
PubMed1992

Interleukin 4 inhibits in vitro proliferation of leukemic and normal human B cell precursors.

In the present study, we have investigated the effects of IL-4 on the proliferation and differentiation of leukemic and normal human B cell precursors (BCP). We have demonstrated that IL-4 significantly inhibited spontaneous [3H]thymidine ([3H]-TdR) incorporation by leukemic blasts from some B lineage acute lymphoblastic leukemia (BCP-ALL) patients (8 of 14). Furthermore, IL-4 was found to suppress the spontaneous and factor-dependent (IL-7 and IL-3) proliferation of normal BCP (CD10+ surface [s] IgM- cells) isolated from fetal bone marrow. Maximum growth inhibition of either leukemic or normal BCP was reached at low IL-4 concentrations (10 U/ml), and the effect was specifically neutralized by anti-IL-4 antibody. IL-4 was further found to induce the expression of CD20 antigen on BCP-ALL cells from a number of the cases examined (5 of 8), but in contrast to leukemic cells, IL-4 failed to induce CD20 antigen on normal BCP. Finally, IL-4 was found to induce neither the expression of cytoplasmic mu chain, nor the appearance of sIgM+ cells in cultures of normal or leukemic BCP. Our data indicate that IL-4 has the potential to inhibit cell proliferation in leukemic and normal human B lymphopoiesis but is unable to drive the transition from BCP to mature B cells.

Antigens, CD↗
PubMed1992

[Acute lymphoblastic leukemia in children: which prognostic factors in 1992?].

Considerable advances were made during the Eighties in the treatment of acute lymphoblastic leukemia in children, using an intensive treatment regimen. The impact of numerous diagnostic variables on the prognosis has been modified; their re-evaluation as prognosis factors is necessary. Great importance is now attributed to the appreciation of the tumor burden, to the immunophenotype, and most importantly to cytogenetic data. This paper describes the prognosis factors currently used to define risk-group, and risk-adapted treatment regimen.

Child↗
PubMed1992

[Cerebrovascular accidents and sickle cell disease].

A 7 year-old girl, with homozygous sickle cell disease experienced two cerebrovascular strokes over an 8-month period. The diagnostic investigations were performed with highly sensitive imaging methods (MRI, angiography). Such a complication raises problems in curative and prophylactic treatment. New diagnostic methods are being evaluated.

Anemia, Sickle Cell↗
PubMed1992

[Results and complications of induction treatment of acute leukemia in children. A personal series of 79 cases (1988-1989)].

In 1988 and 1989, 79 children have been treated for induction of acute leukemia. 68 presented an acute lymphoblastic leukemia (ALL) and 11 an acute non-lymphoblastic leukemia (ANLL). The complete remission rate was 92% (96% in ALL, 73% in ANLL). Fever occurred in 50% of the children, with positive blood cultures in 11 of them. One child died from streptococcal sepsis. No metabolic disorder was noted. Four patients were transferred into the intensive care unit. After 8 days, the treatment of ALL was continued in the outpatient clinic in more than 50% of the cases. The treatment of ANLL is frequently complicated by hemorrhages and sepsis and needs adapted supportive care in a specialized unit.

Adolescent↗