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Biomedical subjects

R Bélanger

Publications and source records attributed to R Bélanger.

At least 19 recordsLinked to original sources
PubMed2001

Allogeneic transplantation for multiple myeloma: further evidence for a GVHD-associated graft-versus-myeloma effect.

We report a series of 37 consecutive patients with multiple myeloma (MM) who received an allograft between 1990 and 2000 at our institution. Median age was 47 years, and nearly 70% of patients were Durie-Salmon stage III. A median of five cycles of chemotherapy were given before transplant, with a median interval between diagnosis and transplant of 9.3 months. We report a nonrelapse mortality rate of 22% with a median follow-up period of 40 months, whereas complete remission (CR) rate at 12 months is estimated at 57%. Treatment failure rate and overall survival at 40 months are estimated at 52% and 32%, respectively. The number of chemotherapy cycles prior to allotransplantation achieved borderline statistical significance as a poor prognosis factor for overall survival (P = 0.05), while the presence of chronic graft-versus-host disease (cGVHD) was significantly correlated with CR achievement (P = 0.036). Our study confirms that early allografting in MM can yield toxicity rates significantly lower than those associated with historical cohorts, and supports the hypothesis that cumulative chemotoxicity has a negative influence on mortality and survival rates. More importantly, our study clearly demonstrates an association between cGVHD and CR and brings further evidence in favor of a graft-versus-myeloma effect.

Adult↗
PubMed2000

Relapse after bone marrow transplantation: evidence for distinct immunological mechanisms between adult and paediatric populations.

Donor lymphocyte infusions are particularly effective for remission induction in malignant cells in patients who relapse after allogeneic progenitor cell transplantation (PCT) and who remain sensitive to the administration of unprimed donor T and/or natural killer (NK) cells present in donor lymphocyte infusions. To determine whether relapse after unmanipulated PCT could be ascribed to donor T and/or NK cell loss or tolerization, we evaluated the chimeric status of 81 patients with haematological malignancies who were receiving allogeneic unmanipulated PCT. The incidence of mixed chimaerism (MC) in unfractionated mononuclear leucocyte samples decreased rapidly after transplant, and was not detectable 4 months after PCT, even in patients who subsequently relapsed. The chimeric status of immune effector cell subsets was then evaluated in 15 patients at the time of relapse. All adults demonstrated complete donor haematopoiesis (CDH) for all cell lineages, whereas T- and NK-cell MC was only found in patients younger than age 13 years (P = 0.004). MC was not found in T nor NK cells of a control group consisting of age-matched paediatric patients in remission after allogeneic PCT. Thus, in adults, T and NK cell MC disappears early after unmanipulated allogeneic PCT and is absent at the time of relapse. However, the identification of donor T and NK cell loss in the paediatric relapsed but not remission patients suggests a distinct mechanism of relapse.

Adolescent↗
PubMed2000

Quantitative analysis of cytomegalovirus (CMV) viremia using the pp65 antigenemia assay and the COBAS AMPLICOR CMV MONITOR PCR test after blood and marrow allogeneic transplantation.

The performance of a commercially available qualitative PCR test for plasma (AMPLICOR CMV Test; Roche Diagnostics) and a quantitative PCR test for plasma and leukocytes (COBAS AMPLICOR CMV MONITOR Test; Roche Diagnostics) was evaluated with samples from 50 blood or marrow allogeneic transplant recipients who received short courses of sequential ganciclovir therapy (2 weeks intravenously followed by 2 weeks orally) based on a positive cytomegalovirus (CMV) pp65 antigenemia (AG) assay. The number of persons with a positive CMV test was significantly higher for leukocyte-based assays (AG, 67.5%; PCR, 62.5%) compared to both quantitative and qualitative PCR tests of plasma (42.5 and 35%, respectively). One person developed CMV disease during the study despite a negative AG assay; in this particular case, all PCR assays were found to be positive 10 days before his death. There was a trend for earlier positivity after transplantation and more rapid negativity after initiation of ganciclovir for the tests performed on leukocytes. The mean number of CMV copies as assessed by PCR was significantly higher in leukocytes than in plasma (P = 0.02). Overall, excellent agreement (kappa coefficient, >0.75) was found only between the two PCR assays (qualitative and quantitative) based on plasma. These results suggest that either the pp65 AG assay or the COBAS AMPLICOR CMV MONITOR Test using leukocytes could be used to safely monitor CMV viremia in related allogeneic blood or marrow transplant recipients. Such a strategy will result in preemptive treatment for about two-thirds of the persons with a relatively low rate (<33%) of secondary viremic episodes following short courses of ganciclovir therapy.

Bone Marrow Transplantation↗
PubMed1998

Lymphoma cell burden in progenitor cell grafts measured by competitive polymerase chain reaction: less than one log difference between bone marrow and peripheral blood sources.

A controversy persists in autologous transplantation as to which source of progenitor cells, bone marrow (BM) or peripheral blood (PB), contains the lowest number of contaminating lymphoma cells, and how mobilization procedures affect these numbers. To accurately measure the number of non-Hodgkin's lymphoma (NHL) cells harboring the bcl-2/immunoglobulin H (IgH) rearrangement in progenitor cell grafts, we developed a nested quantitative competitive polymerase chain reaction assay (QC-PCR). DNA from lymph nodes of four patients with NHL were cloned into the pSK(+) vectors to generate four internal controls (ICs) (two with major breakpoint region [MBR] and two with minor cluster region [mcr] rearrangements). The kinetics of amplification of ICs paralleled those of bcl-2/IgH rearranged genomic DNA. When used in a QC-PCR assay, these ICs were accurate at a 0.2-log level and provided reproducible results, as shown by low intrarun and interrun variability. An excellent correlation between predicted and observed lymphoma cell content (r = .99) was observed over a range of at least 5 logs of rearranged cells. This approach was used to measure involvement by NHL cells at the time of progenitor cell harvest in 37 autologous transplant patients. The number of bcl-2/IgH rearranged cells in BM, PB, and mobilized PB (mPB) was found to vary from 1 to 1.1 x 10(5) per million cells. The number of lymphoma cells present in BM was significantly higher than in PB (P = .0001), with a median difference in lymphoma cell content between BM and PB of 0.48 log of cells (range, -0.7 to 5 logs). In contrast, we found no difference in the concentration of bcl-2/IgH rearranged cells present in BM versus PB progenitor cells mobilized with cyclophosphamide and granulocyte colony-stimulating factor (G-CSF) (mPB) (P = .57). In conclusion, the QC-PCR assay described in this study could measure accurately and reproducibly the number of bcl-2/IgH rearranged cells among normal cells. Differences in levels of contamination by lymphoma cells between BM and PB were of less than one log (10-fold), and no differences in lymphoma cell concentrations were observed between BM and mobilized PB. As more cells are usually infused with mPB than with BM grafts, mPB progenitor cell grafts may actually be associated with higher levels of contamination by lymphoma cells. Furthermore, this QC-PCR assay should provide an important tool to assess the prognostic impact of lymphoma cell burden both in progenitor cell grafts and in vivo.

Adult↗
PubMed1998

Quantitative assessment of hematopoietic chimerism after allogeneic bone marrow transplantation has predictive value for the occurrence of irreversible graft failure and graft-vs.-host disease.

Primary graft failure, secondary to either host-vs.-graft reaction or delayed engraftment, and graft-vs.-host disease (GVHD) are among the most difficult clinical problems to manage in the field of allogeneic bone marrow transplantation (BMT). Early diagnosis of both conditions would greatly improve their outcome. Using fluorescence in situ hybridization (FISH) with an X- and Y-probe mixture, we sequentially monitored chimerism of neutrophils and lymphoid cells from day 1 to 100 in 28 consecutive recipients of sex-mismatched unmanipulated bone marrow grafts. The objective was to quantitatively assess the evolution of chimerism during this crucial time interval and to determine whether chimerism patterns would be predictive of engraftment and GVHD. In recipients with primary graft failure (n=7), the presence of donor-type neutrophils and NK cells as well as the predominance of donor-type T cells distinguished patients who responded to G-CSF (n=5) from nonresponders (n=2). Furthermore, the clearance of host CD3+CD56- cells during days 5-10 posttransplantation was significantly hastened in patients who subsequently developed acute (delta=80%) or chronic (delta=81%) GVHD compared with patients without GVHD (delta=17%). Thus, our data suggest that molecular monitoring of the fate of host/donor hematopoietic cells in the early posttransplantation period could be useful in differentiating patients with delayed engraftment from those with irreversible rejection and in predicting the occurrence of GVHD as soon as day 10. This investigational approach may provide an appropriate basis on which to select adequate treatment for primary graft failure and high-risk candidates that could benefit from novel preemptive therapies for GVHD.

Bone Marrow Transplantation↗
PubMed1996

Phenotypic and functional characterization of peripheral blood and bone marrow natural killer cells prior to autologous transplantation.

NK cells can exert potent anti-leukemia activity after either autologous or allogeneic BMT. However, in autologous blood or marrow transplant patients, NK cell number and/or function could be reduced, and also may vary according to the sampling site. In order to evaluate the hypothesis that blood or marrow grafts from autologous transplant patients exhibit impaired NK cell activity that could contribute to disease recurrence, we evaluated the immunologic characteristics of NK cells in the bone marrow (BM) and peripheral blood (PB) from 27 patients undergoing autologous BMT, and also from 20 normal donors. We measured baseline and interleukin-2 (IL-2)-activated NK cell cytotoxicity, as well as expression of IL-2 receptors (IL-2R) (alpha-chain (p55) and beta-chain (p75)), and adhesion molecules. The cytotoxic activity of PB NK cells was significantly lower in autologous transplant patients than in normal donors (P < 0.0005) and this difference was not mitigated following IL-2 activation. In contrast, BM from autologous patients showed normal NK cell cytotoxicity, but contained higher numbers of NK cells (P < 0.025), with more intense CD56 expression (P < 0.05). Expression of p75 was lower on BM than on PB NK cells in both patients and normal donors. In addition, induction of p55 by IL-2 was abrogated in autologous PB NK cells. Therefore, depending on the site of harvest and the nature of donor cells (pre-BMT vs normal), our results show significant differences in NK cell number, function, and IL-2 receptor expression. This may affect relapse rates following autologous transplants performed with either PB or BM grafts.

Adolescent↗
PubMed1995

Elimination of B-lineage leukemia and lymphoma cells from bone marrow grafts using anti-B4-blocked-ricin immunotoxin.

Bone marrow is the primary site of disease in patients with acute lymphoblastic leukemia (ALL) and is frequently involved in patients with non-Hodgkin's lymphoma (NHL). At the time of autologous bone marrow transplantation, marrow grafts from patients with leukemia and lymphoma are often still contaminated by malignant cells, even when such patients achieve complete clinical remission. In this study, we evaluated the potential of anti-B4-blocked-ricin (anti-B4-bR) immunotoxin to eliminate residual ALL and NHL cells from bone marrow. Anti-B4-bR binds to the CD19 antigen, which is B-lineage specific, and, at concentrations of 5 x 10(-9) M or greater, could eliminate more than 3 logs of CD19+ Nalm-6 or Namalwa cells in a 20-fold excess of normal irradiated bone marrow after only 5 hr of incubation. This activity was abrogated by the addition of anti-B4 but not by the presence of galactose, which is the natural ligand for native ricin. Also, when used at these high concentrations, anti-B4-bR showed little nonspecific toxicity against normal hematopoietic progenitors. In conclusion, a single short exposure to anti-B4-bR is capable of inducing high levels of depletion of CD19+ leukemia and lymphoma cells without significant nonspecific toxicity against normal marrow progenitors. Therefore, anti-B4-bR offers an interesting approach to the elimination of B-lineage malignant cells prior to autologous bone marrow transplantation.

Antibodies, Monoclonal↗
PubMed1995

Distinct patterns of minimal residual disease associated with graft-versus-host disease after allogeneic bone marrow transplantation for chronic myelogenous leukemia.

PURPOSE: Allogeneic bone marrow transplantation (BMT) has been shown to provide effective therapy for chronic myelogenous leukemia (CML), but previous reports have also demonstrated the persistence of bcr-abl-positive cells for months to years after BMT in the majority of patients. To evaluate the biologic significance of persistent bcr-abl-positive cells, we examined the relationship between clinical parameters known to affect the risk of relapse and the ability to detect bcr-abl-positive cells post-BMT. PATIENTS AND METHODS: We analyzed 480 samples from 92 patients at two transplant centers for the presence of bcr-abl-positive cells by polymerase chain reaction (PCR). Two different BMT preparative regimens and protocols for prevention of graft-versus-host disease (GVHD) were used. One center used cyclophosphamide plus total-body irradiation (CY/TBI) and T-cell-depleted marrow; the second center used busulfan plus cyclophosphamide (Bu/CY) and untreated marrow with cyclosporine and methotrexate (Csp/MTX) as GVHD prophylaxis. RESULTS: We first determined the percent of patients at each center with > or = one PCR-positive (PCR+) result at defined intervals post-BMT. Between 0 and 6 months post-BMT, the majority of patients (80% to 83%) in both populations had PCR-detectable bcr-abl-positive cells. Between 6 and 24 months post-BMT, 80% to 88% of patients who received T-cell-depleted marrow remained PCR+, as compared with 26% to 30% of patients who received unmodified marrow. After 24 months post-BMT, the percentage of PCR+ patients was not significantly different in the two populations. This pattern of detection of bcr-abl-positive cells post-BMT followed the development of chronic GVHD in patients who received unmodified marrow. All patients were also divided into three groups based on post-BMT PCR results as follows: (1) persistent PCR+ (n = 29), (2) intermittent PCR-negative ([PCR-] n = 40), and (3) persistent PCR- (n = 23). These three groups were found to have a low, intermediate, and high probability of maintaining remission and disease-free survival, respectively (P = .0001). Intermittent or persistent PCR- results, which reflect levels of minimal residual disease < or = the limit of detection by PCR, were clearly associated with both acute (P = .004) and chronic (P = .000005) GVHD. Nevertheless, 44% of patients without GVHD also had intermittent or persistent PCR- assays. CONCLUSION: The persistence of PCR-detectable bcr-abl-positive cells early post-BMT in more than 80% of patients suggests that neither BMT preparative regimen effectively eradicates CML cells in most patients. Subsequently, acute and/or chronic GVHD are associated with a decreased ability to detect residual bcr-abl-positive cells, which suggests that immunologic mechanisms mediated by donor cells are important for inducing long-term remissions after BMT. The demonstration that 44% of patients without GVHD had either low or undetectable levels of residual leukemia suggests the presence of mechanisms capable of suppression or eradication of CML independent of GVHD.

Acute Disease↗
PubMed1995

[Diagnosis of differentiated thyroid cancers].

Thyroid nodule is a frequent clinical problem. Since the majority of these are benign, it is important to identify the cancers among them and at the same time avoid surgery in most. Fine needle aspiration biopsy is a direct method, reliable and without risk. Today this technique constitute the first step in evaluation of a thyroid nodule. If done properly, it will have a false negative rate of 1 to 2%. In few cases the diagnosis will remain uncertain even after the needle biopsy. In these cases thyroid scan and clinical criteria will be helpful to reach a therapeutic decision.

Biopsy, Needle↗
PubMed1995

Bursitis of the iliopsoas: four cases with pain as the only clinical indicator.

Bursitis of the iliopsoas is a clinical entity rarely encountered, and may be underdiagnosed. Reports in the literature have usually considered the condition to result from an increase in bursal volume. Bursitis of the iliopsoas is most commonly observed in conjunction with pathologies such as rheumatoid arthritis or osteoarthritis of the hip, and is rarely reported as an isolated condition. We describe 4 cases of bursitis of the iliopsoas in which bursal swelling was absent and hip pain was the only clinical indicator. Diagnostic and therapeutic criteria based on clinical and radiological criteria are suggested.

Adult↗
PubMed1994

Graft-host tolerance in bone marrow transplant chimeras. Absence of graft-versus-host disease is associated with unresponsiveness to minor histocompatibility antigens expressed by all tissues.

Because bone marrow (BM) transplantation is used with increasing frequency, it is important to elucidate the mechanisms involved in the establishment of tolerance to host minor histocompatibility antigens (MiHA) in recipients transplanted with T-cell-undepleted marrow grafts. We have previously shown that BM chimeras transplanted across MiHA barriers showed specific unresponsiveness to MiHA expressed on recipient-type concanavalin A blasts. Because expression of many MiHA is tissue-specific, we wanted to determine if chimera T lymphocytes would be tolerant to MiHA expressed by all host tissues and organs. To investigate this issue, we measured in vivo proliferation of lymphoid cells from normal C57BL/10 (B10) mice and (B10-->LP) chimeras in tissues and organs of lethally irradiated syngeneic and allogeneic recipients. Donor B10 cells were either untreated, or depleted with anti-Thy-1.2, anti-CD4, or anti-CD8 antibodies. Transplantation of B10 cells in LP recipients triggered an important T-cell-dependent 125I-dUrd uptake in several organs that involved both CD4+ and CD8+ cells. Using Thy-1-congeneic mice we showed that in long-term chimeras practically all CD4+ and CD8+ T lymphocytes were derived from hematopoietic progenitors and not from mature T cells present in the BM graft. When (B10-->LP) BM chimera cells were injected to secondary recipients, no proliferation was observed in any organ of LP hosts whereas normal proliferation was seen in H-2k allogeneic hosts. Thus, in these BM chimeras, tolerance encompasses MiHA expressed by all organs.

Animals↗
PubMed1994

Quality-of-life following thoracotomy for lung cancer.

Contrary to the issues of perioperative morbidity and survival following surgery for lung cancer, little attention has been given to quality-of-life. To address this, quality-of-life was assessed preoperatively and 1, 3, 6 and 9 months postoperatively in a cohort of 117 consecutive subjects who underwent thoracotomy with a certain or presumptive diagnosis of lung cancer. Those with cancer (n = 91) confirmed at thoracotomy were contrasted to those without (n = 26). Moderate to severe dyspnea, reported in 14% preoperatively, increased to 34% at 1 and 3 months (p < 0.005) but returned to approximately 10% at 6 and 9 months. Similarly, activities of daily living were impaired in 11% preoperatively; this disability increased to 21% at 1 month (p < 0.005), and returned to baseline at 6 and 9 months. Those with cancer compared to those without a postoperative diagnosis of cancer had similar quality-of-life preoperatively but deteriorated more in the postoperative period. This study demonstrates that important deterioration in quality-of-life occurs during the first 3 months postoperatively in those with a final diagnosis of cancer but improvement back to baseline can be expected thereafter.

Activities of Daily Living↗
PubMed1994

Synoviorthesis with colloidal 32P chromic phosphate for the treatment of hemophilic arthropathy.

Between 1977 and 1992, we performed ninety-two synoviortheses (destruction of synovial tissue by intra-articular injection of a radioactive agent) on forty-eight patients who had a severe congenital disorder of hemostasis and chronic hemophilic synovitis that was resistant to conventional treatment. Colloidal 32P chromic phosphate was injected intra-articularly: 1.0 millicurie for knees and 0.5 millicurie for other joints. The duration of follow-up ranged from one to fifteen years. The frequency and importance of bleeding decreased in most of the patients. The range of motion of half of the joints remained stable or improved and that of the other half continued to decrease. Radiographic scores worsened progressively despite the decreased frequency of hemarthrosis. In most patients, the extra-articular leakage of the radioactive agent was slight. Chromosome breakages were observed almost exclusively in patients who were seropositive for human immunodeficiency virus and in whom the CD4-lymphocyte count was decreased from normal. The patients' level of satisfaction with the results was high.

Adolescent↗
PubMed1993

Ergonomics aspects of tree-planting using 'multipot' technology.

The highlights of a descriptive study on the ergonomics and occupational health and safety aspects of tree-planting in Québec are presented. The study was planned to consider the most representative geographical sites, planting technologies, and planting organizations. Semi-directed interviews were made with a mixed group of 48 male and female tree-planters and physiological measurements were made on four male planters. Tools and other equipment were also examined. An analysis of the work identified the main elements of the planting cycle, and the high cardiac rate in the working planters was related more to his manual transportation of seedlings and travel on rough paths than to planting per se. A tree-planter will typically travel 2.4 km carrying 16.8 kg of material and equipment in order to plant an average of 1245 seedlings daily. One out of two interviewed planters reported having a work-related accident or incident during his or her lifetime planting career. The body parts reported most frequently injured were the lower extremities (knee, foot, ankle), the skin, the eyes, and the wrist. Recommendations on the development of appropriate tools and footwear for tree-planters and for further research on repetitive strain injury induced by tree-planting have been made.

Accidents, Occupational↗
PubMed1993

Allogeneic bone marrow transplantation following busulfan-cyclophosphamide with or without etoposide conditioning regimen for patients with acute lymphoblastic leukaemia.

We have investigated the feasibility and efficacy of administering a radiation-free preparative regimen in the setting of allogeneic bone marrow transplantation (BMT) in 40 consecutive patients with acute lymphoblastic leukaemia (ALL). Busulfan (4 mg/kg/d x 4 d) and cyclophosphamide (50 mg/kg/d x 4 d) (BuCy4) were given in 29 patients and 11 received busulfan (4 mg/kg/d x 4 d), etoposide (60 mg/kg) and cyclophosphamide (60 mg/kg/d x 2 d) (BuCy+VP - 16). Median age was 22 years (range 1-50); 11 patients were children < or = 15 years of age. All children and 20 adults were at high risk of relapse pretransplant. Nine adults and one child died from transplant-related toxicity. 11 patients relapsed at a median of 11 months post-transplant (range 2-27). The 3-year Kaplan-Meier estimated probability of relapse was 42.1% and found to be significantly lower in patients with chronic GVHD (P = 0.03). 19 patients are leukaemia-free survivors with a median follow-up of 33 months (range 7-59). The Kaplan-Meier actuarial probability of disease-free survival at 3 years was 43% for all patients. 63.6% for children versus 30.2% for adults (P = 0.24) and 51.6% for patients transplanted in first remission versus 30.2% for those transplanted in subsequent remissions (P = 0.20).

Adolescent↗
PubMed1992

Cytogenic characterization of primary refractory anemia.

Refractory anemia (RA) is the only myelodysplastic syndrome (MDS) devoid of quantitative marrow diagnostic criteria. The diagnosis rests mainly on the subjective identification of qualitative abnormalities according to the French-American-British criteria (FAB) involving one or more bone marrow hematopoietic cell lineages. The occurrence of nonrandom chromosome abnormalities remains the hallmark of the disease and the only means of investigation which confirms the disease objectively. With the purpose in mind to further characterize RA among MDS, we have undertaken a prospective high resolution banding chromosome analyses of bone marrow cells in patients with primary refractory anemia (PRA) with the aim of defining a cytogenetic phenotype and of assessing the clinical relevance of clonal abnormalities at initial diagnosis. Of 39 patients consecutively referred for chromosome analyses with a diagnosis of RA according to the FAB criteria, 27 patients had PRA and fulfilled our criteria for adequate chromosome analyses. Median age was 68 years. Fourteen of 27 patients (52%) had clonal chromosomal abnormalities at diagnosis. None of the patients showed a complex karyotype; 9/14 (64%) had a mixture of normal and abnormal cells. Interstitial or terminal deletions, involving chromosomes 5, 6, 7, 9, 11, 12, and 20, were found in 11/14 (79%) of the patients. Comparison of survival between patients with and without abnormalities showed no difference. The presence of clonal abnormalities did not predict transformation to acute myeloblastic leukemia (AML) nor was it associated with poor survival. In this study, patients with PRA were found to have a predominant pseudodiploid karyotypic pattern characterized by interstitial and/or terminal deletions as opposed to derivatives, specific and non-specific balanced translocations, or other structural and numerical abnormalities. We were unable to reveal any prognostic significance to the presence of these clonal abnormalities at initial diagnosis.

Adult↗