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Biomedical subjects

Y Bertrand

Publications and source records attributed to Y Bertrand.

At least 37 records · Page 2Linked to original sources
PubMed2004

Effects of allogeneic bone marrow transplantation on pulmonary function in 80 children in a single paediatric centre.

We retrospectively reviewed the results of serial pulmonary function tests (PFT) after allogeneic bone marrow transplantation (BMT) performed in 80 children at a single institution over a 16-year period. We looked for associations linking PFT results to graft-versus-host disease (GVHD), conditioning regimen (total body irradiation (TBI) vs busulphan), and cytomegalovirus immune status. The median follow-up after BMT was 4 years. At 2 years after BMT, significant declines were found in forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), as compared to baseline. Both FEV1 and the FEV1/FVC ratio showed significantly greater reductions in the group conditioned with busulphan (n=22) than in the group conditioned with TBI (n=49) and were significantly lower in the patients with (n=16) than without (n=64) chronic GVHD. Busulphan may be associated with greater long-term lung toxicity than TBI. The relevance of this finding to selection of conditioning regimens for BMT should be examined in the light of the overall pattern of side effects. Chronic GVHD was associated with airway obstruction.

Adolescent↗
PubMed2004

Antileukemic and long-term effects of two regimens with or without TBI in allogeneic bone marrow transplantation for childhood acute lymphoblastic leukemia.

Between September 1986 and June 1997, 24 children with high-risk ALL in CR1 were allografted after TAM (fractionated TBI, high-dose Ara-C, and melphalan; n = 10) or BAM protocol (busulfan, high-dose Ara-C, and melphalan; n = 14). The EFS for transplants from sibling donors was 33% with TAM and 62% with BAM (P = 0.148). The probability of acute GvHD was 70% with TAM and 15% with BAM (P = 0.003). Four of 17 evaluable patients relapsed: one after TAM and three after BAM. In all, 46 other children transplanted in CR beyond CR1 were studied for sequelae. Long-term side effects were more frequent in TAM vs BAM. In children with ALL, busulfan may be a good alternative to TBI to improve the quality of life.

Adolescent↗
PubMed2004

Human mesenchymal stem cells suppress induction of cytotoxic response to alloantigens.

Mesenchymal stem cells (MSC) fail to induce allogeneic responses in mixed lymphocyte reaction assays. Because MSC express HLA class I molecules, here we investigated whether they could be recognized as allogeneic targets by cytolytic T lymphocytes (CTL). With this aim, CTL precursor (CTLp) frequencies were measured following stimulation of T cells with either allogeneic mononuclear cells (MNC) or MSC originated from the same human bone marrow donor. Lysis of MSC was measured at day 10 of culture in standard chromium release assays. In addition, allogeneic PHA blast T cells or B-EBV lymphoblastoid cell lines (LCLs) generated from the same donor were used as positive controls of lysis. Our results showed that when allogeneic MNC were used to stimulate T cells, a high CTLp frequency was detected towards MSC targets. However, when MSC were used as stimulators, CTLp frequencies were markedly altered whatever the targets used, i.e.: MSC, PHA blast T cells or EBV-B LCLs. Moreover, when graded concentrations of MSC were added together with MNC upon stimulation of alloreactive T cells, we observed a dose-dependent decrease in CTLp frequencies towards MSC targets. This inhibition of MSC lysis was partially overcome by adding exogenous rh-IL-2 from the beginning of cultures. In addition, this suppressive effect was totally reproduced when, instead of MSC, supernatant harvested from MSC cultures was added to allogeneic MNC, upon stimulation of alloreactive T cells. In conclusion, our results demonstrate that MSC which can be recognized as targets by pre-activated alloreactive CTLs, may be able to suppress differentiation of CTL precursors into CTL effectors through secretion of suppressive factors.

Cell Differentiation↗
PubMed2003

Lymphocyte-predominant Hodgkin's lymphoma in children: therapeutic abstention after initial lymph node resection--a Study of the French Society of Pediatric Oncology.

PURPOSE: To clarify treatment strategy for lymphocyte-predominant Hodgkin's lymphoma (LPHL), the French Society of Pediatric Oncology initiated a prospective, nonrandomized study in 1988. Patients received either standard treatment for Hodgkin's lymphoma or were not treated beyond initial adenectomy. PATIENTS AND METHODS: From 1988 to 1998, 27 patients were available for study. Twenty-four patients were male, and median age was 10 years (range, 4 to 16 years). Twenty-two, two, and three patients had stage I, II, and III disease, respectively. Thirteen patients (stage I, n = 11; stage III, n = 2) received no further treatment after initial surgical adenectomy (SA). Fourteen patients received combined treatment (CT; n = 10), involved-field radiotherapy alone (n = 1), or chemotherapy alone (n = 3). The two groups were comparable for clinical status, treatment, and follow-up. RESULTS: Twenty-three of 27 patients achieved complete remission (CR). With a median follow-up time of 70 months (range, 32 to 214 months), overall survival to date is 100%, and overall event-free survival (EFS) is 69% +/- 10% (SA, 42% +/- 16%; CT, 90% +/- 8.6%; P <.04). If we considered only the patients in CR after initial surgery (n = 12), EFS was no longer significantly different between the two groups. Patients with residual mass after initial surgery (n = 15) had worse EFS if they did not receive complementary treatment (P <.05). CONCLUSION: Although based on a small number of patients, our study showed that (1). no further therapy is a valid therapeutic approach in LPHL patient in CR after initial lymph node resection, and (2). complementary treatment diminishes relapse frequency but has no impact on survival.

Adolescent↗
PubMed2003

Hematopoietic stem cell transplantation in patients with severe Langerhans cell histiocytosis and hematological dysfunction: experience of the French Langerhans Cell Study Group.

The aim of this study was to assess the results of hematopoietic stem cell transplantation (HSCT) in refractory Langerhans cell histiocytosis (LCH). Among 85 patients with LCH and hematological dysfunction diagnosed in France between 1987 and 2000, eight received HSCT in six institutions. Median age at diagnosis was 0.54 years. The median LCH activity score at diagnosis was 10 (range 3-20). All patients responded poorly to initial chemotherapy. At the time of HSCT, the median activity score was 16.5 (range 7-18). HSCT was autologous in three cases and allogeneic in five cases. The conditioning regimen consisted of TBI in two cases and chemotherapy alone in six cases. Conditioning had to be attenuated in two patients. All patients had persistent active disease after autologous HSCT, which was fatal in two cases and controlled by chemotherapy in one case. After allogeneic HSCT, two patients died from toxicity and three had complete responses; two patients had had no recurrences after 21 months and 7 years of follow-up, while the other patient relapsed and died from sepsis related to splenectomy. HSCT for refractory LCH can thus be highly toxic but can also achieve sustained disease control.

Chimera↗
PubMed2003

Outcome of 27 patients with Hurler's syndrome transplanted from either related or unrelated haematopoietic stem cell sources.

Over the last 15 years, we have performed a total of 30 haematopoietic stem cell transplants on 27 children suffering from Hurler's syndrome. These children were of median age 11 months at the time of diagnosis and 25 months at the time of transplantation. The phenotype was severe in 21 cases (78%). The donor was familial in 13 cases: nine genotypically identical, one phenotypically identical father and three HLA-mismatched donors. Unrelated donors were selected in 17 cases: four phenotypically identical and 13 with 1-4 HLA mismatches. The conditioning regimen generally consisted of busulphan 600 mg/m(2) plus cyclophosphamide (Endoxan) 260 mg/kg and cyclosporin with methotrexate for GvHD prophylaxis. Rabbit anti-thymocyte globulin (Thymoglobuline) was given for all unrelated or familial mismatched transplantations. The median nucleated cell dose infused was 6.00 x 10(8) TNC/kg. No bone marrow (apart from one) was T cell depleted. For first transplants, engraftment was observed in 23/27 patients (pts) (85%). Primary graft failure was observed in 4/27 patients (16%), two were retransplanted from an unrelated donor, one with success. Four patients have died. The primary cause of death was infection in three cases (TRM : 11%) and disease progression in one case, after primary graft failure. Of the 23 living patients, two have disease progression after graft failure and 21 (78%) have functional grafts with a favourable long-term outcome after a median follow-up of 4.7 years, having either full or mixed chimaerism. Among surviving patients with functional grafts, 13 (62%) were transplanted from unrelated donors of whom 10 (77 %) had HLA disparities. There was a remarkably low incidence of GvHD. In our experience, haematopoietic stem cell transplantation using an HLA-matched familial donor or an HLA-matched or -mismatched unrelated donor without T cell depletion or irradiation can achieve a favourable outcome in Hurler's syndrome, with improved cognitive function, but with a limited effect on the corneas and skeleton.

Adolescent↗
PubMed2003

Relationship between CsA trough blood concentration and severity of acute graft-versus-host disease after paediatric stem cell transplantation from matched-sibling or unrelated donors.

In order to determine optimal CsA trough blood concentrations (TBC) in the early post transplantation period, we analysed relationships between TBC and acute graft-versus-host disease (aGVHD) in paediatric SCT. A total of 94 children consecutively underwent allogeneic stem cell transplantation (SCT) from: matched-sibling (MSD) (n=36), mismatched-related (MMRD) (n=3) and unrelated donors (UD) (n=55). GVHD prophylaxis usually included CsA alone or with methotrexate. Antithymocyte globulin was added in UD-SCT. TBC during the first weeks of post transplantation were estimated retrospectively by a Bayesian pharmacokinetic method and statistically associated with aGVHD. In MSD-SCT, the mean TBC during the first 2 weeks post transplantation were 42+/-10 and 90+/-7 ng/ml, respectively, in patients with grade II-IV and 0-I aGVHD (P=0.001). In SCT from UD and MMRD, TBC were 73+/-4 vs 95+/-8 ng/ml (P=0.284). For TBC >85 ng/ml, no patient developed grade II-IV aGVHD, 10 developed mild aGVHD and 30 had no aGVHD. For TBC <65 ng/ml, 7/11 patients receiving an MSD-SCT and 4/18 receiving an UD- or MMRD-SCT developed grade II-IV aGVHD. The mean TBC corresponding to each grade were: no GVHD: 101+/-10 ng/ml, mild: 77+/-11 ng/ml, moderate: 61+/-13 ng/ml, severe: 56+/-15 ng/ml (P <0.001). These results reveal a strong relationship between TBC during the early post transplantation period and the severity of aGVHD in paediatric SCT.

Acute Disease↗
PubMed2003

Clinical and pharmacological risk factors for acute graft-versus-host disease after paediatric bone marrow transplantation from matched-sibling or unrelated donors.

The aim of this study was to identify the risk factors for acute graft-versus-host disease (aGVHD) in children transplanted from a matched-sibling donor (MSD) or an unrelated donor (UD). In all, 87 children consecutively underwent allogeneic bone marrow transplantation (BMT) from MSD (n=36), and UD (n=51). GVHD prophylaxis included CsA alone (n=33) or with MTX (n=51). ATG was added in UD-BMT and thalassemic recipients. CsA whole-blood concentrations were measured by EMIT and the dosing regimen was monitored by Bayesian pharmacokinetic modelling. Trough blood concentration (TBC) during the first 2 weeks post transplantation was lower in children who developed grade II-IV aGVHD than those developing no GVHD or only grade I (57+/-9 vs 94+/-8 ng/ml, P=0.007), whereas peak blood concentration and area under concentration curve vs time were similar in both groups. TBC <85 ng/ml and 'use of MTX' were associated with aGVHD in MSD-SCT (P=0.003 and 0.007, respectively) as well as in UD-SCT (P=0.006 and 0.003). Donor age >or=8 years was significant only in MSD-BMT. Our results have shown the significant decisive role of pharmacological factors such as CSA TBC or use of MTX in the occurrence of GVHD in MSD as well as in UD paediatric BMT.

Acute Disease↗
PubMed2002

[Rectal localization of Burkitt's lymphoma].

BACKGROUND: Rectal tumors are rare in childhood and among them malignant tumors are even less common. Only eight cases of primary rectal lymphomas were reported in children, with various presenting signs and histology. Burkitt's lymphomas are among these cases. CASE REPORT: A five-year-old child presented with hematochezia and unusual constipation. The rectal examination showed a voluminous intra rectal mass. Radiographic and pathologic examinations led to the diagnostic of Burkitt's lymphoma with medullary involvement. Complete remission was obtained after initial chemotherapy but a local relapse occurred and the child died eight months later. CONCLUSION: Hematochezia associated with unusual constipation impose a rectal examination. Early diagnosis of a rectal tumor may allow patients survival.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

Reticular dysgenesis: HLA non-identical bone marrow transplants in a series of 10 patients.

Reticular dysgenesis is a very rare congenital immunodeficiency classified within the severe combined immunodeficiencies (SCID) and characterized by impairment of both lymphoid and myeloid cell development. We report our experience in 10 patients with RD, treated between 1979 and 1999 with HLA-haploidentical hematopoietic stem cell transplantation (HSCT). All children but one were symptomatic within the first days of their lives. Five patients required two HSCT. Five patients received conditioning therapy with busulfan (16 mg/kg) and cyclophosphamide. Three of them are alive and well with myeloid and T and B cell lymphoid reconstitution, whereas two patients died (one chronic graft-versus-host disease, one pneumonitis). Transplantation without or with other conditioning regimens in the other five cases led to absent or incomplete engraftment and none of these cases survived. These results demonstrate the mandatory need for intensive conditioning before haploidentical HSCT in RD to achieve full lymphoid and myeloid engraftment.

Bone Marrow Transplantation↗
PubMed2001

Artemis, a novel DNA double-strand break repair/V(D)J recombination protein, is mutated in human severe combined immune deficiency.

The V(D)J recombination process insures the somatic diversification of immunoglobulin and antigen T cell receptor encoding genes. This reaction is initiated by a DNA double-strand break (dsb), which is resolved by the ubiquitously expressed DNA repair machinery. Human T-B-severe combined immunodeficiency associated with increased cellular radiosensitivity (RS-SCID) is characterized by a defect in the V(D)J recombination leading to an early arrest of both B and T cell maturation. We previously mapped the disease-related locus to the short arm of chromosome 10. We herein describe the cloning of the gene encoding a novel protein involved in V(D)J recombination/DNA repair, Artemis, whose mutations cause human RS-SCID. Protein sequence analysis strongly suggests that Artemis belongs to the metallo-beta-lactamase superfamily.

Amino Acid Sequence↗
PubMed2001

Pharmacokinetics of liposomal daunorubicin (DaunoXome) during a phase I-II study in children with relapsed acute lymphoblastic leukaemia.

PURPOSE: The pharmacokinetics of DaunoXome were studied during a multicentric phase I-II study performed in children suffering from relapsed acute lymphoblastic leukaemia and treated on a weekly schedule. PATIENTS AND METHODS: A group of 18 patients were studied during the first course of treatment at dose levels between 40 and 120 mg/m2. Blood samples were obtained up to 72 h after infusion. The liposomal and free forms of daunorubicin, as well as daunorubicinol, were separated and quantified by HPLC using fluorometric detection, and data were analysed using a model-independent approach. RESULTS: Unchanged liposomal daunorubicin disappeared from plasma following a monoexponential decay. Its AUC represented 95.8% of the total fluorescent species found in plasma and increased linearly with the dose administered. The elimination half-life was 5.23 h, total plasma clearance 0.344 1/h per m2, and volume of distribution at steady state 2.08 l/m2. Free daunorubicin and daunorubicinol were detected in plasma at all time-points studied. Their AUCs represented, respectively, 2.53% and 1.70% of total fluorescent species and their elimination half-lives were, respectively, 16.6 h and 22.3 h. The daunorubicinol/daunorubicin AUC ratio was 0.82%. CONCLUSIONS: This study is the first to demonstrate that free daunorubicin is present in plasma after DaunoXome administration and that it originates from in vivo release from the liposomes. The pharmacokinetics of free daunorubicin appeared to be comparable to those observed after conventional administration. However, the concentration of daunorubicinol appeared to be lower than that found after conventional administration of daunorubicin.

Adolescent↗
PubMed2001

[Burkitt's lymphoma revealed by acute intussusception in children].

STUDY AIM: Burkitt's lymphomas are rarely revealed by acute intestinal intussusception in children. The study aim was to report eight cases. PATIENTS AND METHODS: Between 1988 and 1999, eight children, seven boys and one girl (mean age: 6 years) were hospitalized for an acute abdominal syndrome. Abdominal ultrasonography showed intestinal intussusception (n = 8) primitive tumor (n = 2), mesentivic lymph nodes (n = 2) and liver nodes (n = 1). Enema (n = 6) confirmed presence and irreductibility of the intestinal intussusception. A laparotomy was performed on emergency in seven patients and found the primitive tumor in 6. The procedure consisted in disinvagination (n = 4) and intestinal resection for ischaemia (n = 2). One patient was not operated on and the diagnosis was performed through ultrasonography guided tumoral puncture. RESULTS: According to the Murphy classification, there were 2 stage II, 3 stage III and 3 stage IV patients. With LMB protocol chemotherapy, a complete remission was observed following the first cure. All the children were alive at the time of this study with a follow-up longer than one year after the complete remission. CONCLUSION: Abdominal sonography is the most efficient examination for the diagnosis of intestinal intussusception and sometimes of the primitive lesion. In the absence of sonographic intestinal impair, thanks to ultrasonography guided tumoral puncture, diagnosis may be made and chemotherapy started. If the lymphoma is not visualized with ultrasonography, an emergency laparotomy is necessary for the diagnosis of the lymphoma and the intestinal resection in case of necessity. Burkitt's lymphoma is very sensible to chemotherapy.

Acute Disease↗
PubMed2001

Lupus nephritis in a child with AIDS.

Concomitant acquired immunodeficiency syndrome (AIDS) and lupus nephritis is an exceptional feature in white patients. A white boy with maternofetal human immunodeficiency virus (HIV) infection had no medical follow-up until he presented at 12 years of age with a nephrotic syndrome, macrohematuria, renal failure, pancytopenia, and low CD4(+) cell count. A renal biopsy revealed severe lupus nephritis (World Health Organization class IV) with specific immune deposits in the absence of any clinical sign of systemic lupus erythematosus or specific autoantibodies at the time of diagnosis. The treatment consisted of methylprednisolone pulses followed by oral prednisone; antiretroviral triple therapy was started a few weeks later, which contributed to clinical and biologic improvement. To our knowledge, this is the first case report of lupus-like nephritis in a white child with AIDS, whose outcome might be improved significantly by a combination of steroids and antiretroviral therapy.

AIDS-Associated Nephropathy↗
PubMed2001

[Collagen gastritis, an unusual cause of anemia in children. Report of 2 cases].

UNLABELLED: When a child presents a severe anemia or resistant to iron supplementation, an upper gastrointestinal endoscopy has to be realized to find special causes. CASE REPORTS: We report observations of two patients, respectively 11 and 12 years old, who were admitted to hospital for a severe microcytic, hypochromic, aregenerative anemia (hemoglobin less than 50 g/L) due to an iron deficiency. The two children's history did not reveal a deficient diet, gastrointestinal tract disorder, ingested toxic or gastrotoxic drugs, or exteriorized hemorrhage. Upper gastrointestinal endoscopy showed a macroscopic pattern of gastritis. The stomach biopsies revealed subepithelial collagenous deposits. CONCLUSION: The collagenous gastritis involves lesions similar to those described in the small intestine (collagenous sprue) and colon (collagenous colitis). The pathogenic factors of the three entities are presently unknown, but they are often associated with autoimmune pathology. These two observations are the third and the fourth pediatric cases described.

Anemia↗
PubMed2001

Epstein-Barr virus-related lymphoproliferative disease complicating childhood acute lymphoblastic leukemia: no recurrence after unrelated donor bone marrow transplantation.

A 16-year-old boy in complete remission of ALL, undergoing oral maintenance therapy, developed intestinal perforation related to EBV-associated lymphoproliferative disease (LPD). He was successfully managed with surgical resection, acyclovir, immunoglobulins and discontinuation of maintenance therapy. Leukemic marrow relapse occurred 3 months later, treated by polychemotherapy followed by unmanipulated BMT from a matched unrelated EBV seropositive donor. Donor lymphocytes were infused twice after transplant because of delayed immunologic recovery and severe CMV colitis. This was followed by acute GVHD requiring prolonged immunosuppressive treatment. Despite intensive and prolonged immunosuppression, recurrence of LPD was not observed. Following EBV-related LPD, allogeneic BMT can be performed if indicated. Selection of an EBV seropositive donor is of major importance for the prevention of LPD recurrence as the recipient may be protected by passive transfer of EBV-specific cytotoxic T cells.

Adolescent↗