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Biomedical subjects

A Najman

Publications and source records attributed to A Najman.

At least 37 records · Page 2Linked to original sources
PubMed1996

Recombinant human erythropoietin in transfusion-dependent anemic patients with multiple myeloma and non-Hodgkin's lymphoma--a randomized multicenter study. The European Study Group of Erythropoietin (Epoetin Beta) Treatment in Multiple Myeloma and Non-Hodgkin's Lymphoma.

One hundred twenty-one anemic, transfusion-dependent patients with multiple myeloma (MM) or low-grade non-Hodgkin's lymphoma (NHL) were randomly allocated to receive (a) recombinant human erythropoietin (rhEPO) 10,000 U/d subcutaneously 7 days a week (fixed dose group) (n = 38), or (b) rhEPO 2,000 U/d subcutaneously for 8 weeks followed by step-wise escalation of the rhEPO dose (titration group) (n = 44), or (c) no rhEPO therapy (control group) (n = 39). The total treatment period was 24 weeks. There were no differences between the three groups with regard to baseline clinical, demographic, or health status measures. The cumulative response frequency, defined as elimination of the transfusion need in combination with an increase in the hemoglobin concentration by >20 g/L, was 60% in both rhEPO treatment groups and 24% in the control group (P = .01 and .02, respectively, log rank test). For patients in the titration group the response rate on the first dose level (2,000 U/d) was only 14%. Cox's univariate regression analysis revealed that an inadequately low endogenous erythropoietin concentration in relation to the degree of anemia and a baseline platelet concentration > or = 100 x 10(9)/L were significant predictors for response to rhEPO therapy (P < .01). Multivariate regression analysis showed that relative erythropoietin concentration was the most important factor and the platelet count had no additional influence on response. Treatment with rhEPO was well tolerated. We conclude that treatment with rhEPO may be indicated in anemic MM and NHL patients with a relative erythropoietin deficiency. An initial dose of 5,000 U/d subcutaneously may be recommended.

Adult↗
PubMed1996

Monitoring of cytomegalovirus infection and disease in bone marrow recipients by reverse transcription-PCR and comparison with PCR and blood and urine cultures.

Preemptive therapy is a promising strategy for the prevention of serious cytomegalovirus (CMV) disease after bone marrow (BM) transplantation but requires relevant diagnostic tests. We compared the clinical value of a reverse transcription (RT)-PCR method, which detected a late viral mRNA in peripheral blood leukocytes (PBL), with a PCR method that detected the viral DNA in PBL and with viral culture from leukocytes and urine for the diagnosis of symptomatic CMV infection after BM transplantation. Forty-five consecutive BM recipients were prospectively tested at weekly intervals by the four methods. CMV infection, demonstrated either by the culture of CMV or by repeated detection of viral DNA, was observed in 28 patients, but only 14 developed CMV-related clinical symptoms. The clinical sensitivity and specificity of each technique for detection of symptomatic infection were, respectively, 36 and 74% for urine culture, 43 and 84% for leukocyte culture, 100 and 65% for PCR, and 71 and 94% for RT-PCR. Although PCR detection of DNA in PBL was the earliest and most sensitive technique for the diagnosis of CMV infection, RT-PCR was more predictive of the onset of CMV-related clinical symptoms. These data suggest that both molecular methods should be used for identifying BM recipients at highest risk of CMV disease.

Adolescent↗
PubMed1996

Heterogeneity of B lineage acute lymphoblastic leukemias (B-ALL) with regard to their in vitro spontaneous proliferation, growth factor response and BCL-2 expression.

The spontaneous proliferation and the effects of 8 various growth factors (GF) were evaluated on leukemic cells from 27 patients with B-lineage ALL. Two groups of ALLs were distinguished. ALLs from group I (21 patients) exhibited a low spontaneous proliferative rate and were stimulated by IL-3 + IL-7 +/- SCF and/or LIF, while ALLs from group II (6 patients) had a high spontaneous proliferative rate and did no longer require this combination of GFs for proliferation. No effect of bFGF, IGF-I, IL-10 and IL-11 alone or in combination, was observed. Such differences in the behaviour of B-ALLs indicated that the GF requirement of ALL blasts was not related to the presence of serum in the culture nor to the pattern of reactivity of ALL blasts for B lymphoid markers or CD34 antigen. Furthermore, we showed in 1/9 cases that high proliferation might be due to an overexpression of the bcl-2 proto-oncogene and to the acquisition of an autocrine secretion.

Adult↗
PubMed1996

Thymosin beta4, inhibitor for normal hematopoietic progenitor cells.

Thymosin beta4 (Tbeta4), isolated from the calf thymus fraction 5, has a ubiquitous localization and plays a pleiotropic role in both the immune and nonimmune systems. Because it contains at its N-terminal end the sequence of a known inhibitor of hematopoiesis, the acetylated tetrapeptide Ac-N-Ser-Asp-Lys-Pro (AcSDKP, Goralatide), we have assayed Tbeta4 on human hematopoietic cells. We demonstrate that it inhibits normal bone marrow progenitor cell growth; indeed, it decreased the growth of both granulo-macrophagic and erythroid progenitors and reduces their percentage in S phase. Furthermore, we show that Tbeta4 reduces both the clonogenicity and the cell proliferation of purified CD34+ cells induced by a combination of seven growth factors. Although Tbeta4's inhibitory effect is very similar to that of AcSDKP, we demonstrate, using neutralizing antibodies and a truncated form of Tbeta4 devoid of the AcSDKP sequence, that the inhibitory effect of Tbeta4 is not mediated by the sequence AcSDKP. These data indicate that Tbeta4 is a novel inhibitor for human normal hematopoietic progenitors.

Amino Acid Sequence↗
PubMed1996

Autologous bone marrow transplantation is feasible in patients with a prior history of invasive pulmonary aspergillosis.

We report on seven adult leukemic patients who were autografted in spite of a prior history of invasive pulmonary aspergillosis (IPA). Their median age was 41 years (range: 19-61); six patients were male and one female. All seven had acute myeloblastic leukemia (AML) and underwent an autologous marrow transplantation (ABMT) with a marrow purged in vitro by mafosfamide. IPA was suspected prior to ABMT on clinical and radiological features. CT scan confirmed nodular infiltrates and cavitations in six cases. Microbiological documentation consisted of: identification of the fungus from bronchoalveolar lavage: one case, positive antigenemia: one case, positive antibodies: two cases. Prior ABMT patients received amphotericin B for a median total dose of 1915 mg (range: 970-3300). No patient underwent surgery. The median time from diagnosis of IPA to ABMT was 7.3 months (range: 3-10). During ABMT all patients received prophylactic amphotericin B and itraconazole. No patient died from toxicity and no IPA reactivation was observed in any patients. Post-graft, itraconazole was kept on for a median of 3 months (range: 3-5). This study demonstrates that IPA occurring during the management of AML patients is not necessarily a contraindication to subsequent ABMT.

Acute Disease↗
PubMed1995

Recombinant human erythropoietin in the anemia associated with multiple myeloma or non-Hodgkin's lymphoma: dose finding and identification of predictors of response.

Previous phase I-II clinical trials have shown that recombinant human erythropoietin (rHuEpo) can ameliorate anemia in a portion of patients with multiple myeloma (MM) and non-Hodgkin's lymphoma (NHL). Therefore, we performed a randomized controlled multicenter study to define the optimal initial dosage and to identify predictors of response to rHuEpo. A total of 146 patients who had hemoglobin (Hb) levels < or = 11 g/dL and who had no need for transfusion at the time of enrollment entered this trial. Patients were randomized to receive 1,000 U (n = 31), 2,000 U (n = 29), 5,000 U (n = 31), or 10,000 U (n = 26) of rHuEpo daily subcutaneously for 8 weeks or to receive no therapy (n = 29). Of the patients, 84 suffered from MM and 62 from low- to intermediate-grade NHL, including chronic lymphocytic leukemia; 116 of 146 (79%) received chemotherapy during the study. The mean baseline Hb level was 9.4 +/- 1.0 g/dL. The median serum Epo level was 32 mU/mL, and endogenous Epo production was found to be defective in 77% of the patients, as judged by a value for the ratio of observed-to-predicted serum Epo levels (O/P ratio) of < or = 0.9. An intention-to-treat analysis was performed to evaluate treatment efficacy. The median average increase in Hb levels per week was 0.04 g/dL in the control group and -0.04 (P = .57), 0.22 (P = .05), 0.43 (P = .01), and 0.58 (P = .0001) g/dL in the 1,000 U, 2,000 U, 5,000 U, and 10,000 U groups, respectively (P values versus control). The probability of response (delta Hb > or = 2 g/dL) increased steadily and, after 8 weeks, reached 31% (2,000 U), 61% (5,000 U), and 62% (10,000 U), respectively. Regression analysis using Cox's proportional hazard model and classification and regression tree analysis showed that serum Epo levels and the O/P ratio were the most important factors predicting response in patients receiving 5,000 or 10,000 U. Approximately three quarters of patients presenting with Epo levels inappropriately low for the degree of anemia responded to rHuEpo, whereas only one quarter of those with adequate Epo levels did so. Classification and regression tree analysis also showed that doses of 2,000 U daily were effective in patients with an average platelet count greater than 150 x 10(9)/L. About 50% of these patients are expected to respond to rHuEpo. Thus, rHuEpo was safe and effective in ameliorating the anemia of MM and NHL patients who showed defective endogenous Epo production. From a practical point of view, we conclude that the decision to use rHuEpo in an individual anemic patient with MM or NHL should be based on serum Epo levels, whereas the choice of the initial dosage should be based on residual marrow function.

Adult↗
PubMed1995

Treatment of Waldenstrom's macroglobulinemia with very low doses of alpha interferon.

Waldenström's macroglobulinemia (WM) is a differentiated B-cell malignancy which is usually less responsive to standard chemotherapy because of low-proliferating cells. Interferon alpha has been shown to possess a therapeutic action in numerous B-cell malignancies including the early stage of chronic lymphocytic leukemia, multiple myeloma, follicular lymphoma and hairy cell leukemia. Fourteen patients with progressive WM were included in a pilot study using very low dose of interferon alpha-2a (1 Million Units 3 times a week). The mean duration of treatment was 10.3 months (range 2-44). Six of 14 (42%) patients presented an increase in the hemoglobin level (> or = 0.9 g/dL) and 4/14 (28%) had a substantial decrease of the monoclonal component (> or = 20% of reduction). Only two patients presented both types of response, while the others with an increase in the hemoglobin level had a slight decrease in the monoclonal component (MC) (1 patient), a stable MC (1 patient) or a slight increase of MC (1 patient). One additional patient had a 15% decrease of the MC with a stable hemoglobin level. Response was observed within 3 months with a median duration of 6 months. Treatment was stopped for 3 patients because of flu-like symptoms (2 patients), or thrombocytopenia (1 patient). Follow up was possible in 12 patients lasting up to a maximum of 30 months after discontinuing treatment. Seven patients died, including 4 with progressive disease, two of infection and one of cardiac failure. In the view of these results, very low dose of interferon alpha may constitute a new approach for treatment of some cases of WM.

Aged↗
PubMed1995

Comparison of the inhibitory effect of AcSDKP, TNF-alpha, TGF-beta, and MIP-1 alpha on marrow-purified CD34+ progenitors.

The aim of this study was to compare the inhibitory effect of the tetrapeptide AcSDKP, tumor necrosis factor-alpha (TNF-alpha), which contains the sequence of the peptide, transforming growth factor-beta (TGF-beta), and macrophage inflammatory protein-1 alpha (MIP-1 alpha) on sorted CD34+ cells using both proliferation and clonogenic assays. Although a short treatment with any of the molecules decreased the growth of colony-forming unit granulocyte/macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E) progenitors (except for TNF-alpha as it is a greater inhibitor for CFU-GM), further experiments using a 6-day liquid culture in the presence of a combination of growth factors (recombinant human interleukin-3 [rhIL-3], IL-6, IL-1 beta, GM colony-stimulating factor [GM-CSF], G-CSF, erythropoeitin [Epo], and stem cell factor [SCF]) allowed us to determine a number of differences between their effects: 1) TGF-beta and TNF-alpha induced a stronger decrease in the proliferation and clonogenicity of CD34+ subsets than MIP-1 alpha and AcSDKP, 2) the dose-response curves appeared different, and 3) contrary to TGF-beta and TNF-alpha, AcSDKP and MIP-1 alpha required repeated addition to induce inhibition. Therefore, our data clearly show that while the inhibitory effect of TNF-alpha and AcSDKP appeared to be different, there is a close similarity in the effect of AcSDKP and MIP-1 alpha on normal human progenitor response to the combination of growth factors used.

Antigens, CD↗
PubMed1995

Pharmacokinetics of a more reliable Chloraminophene formulation.

The pharmacokinetics of two formulations of chlorambucil, Chloraminophene capsules and Chloraminophene tablets, were compared in 12 patients in a randomized cross-over study. Chlorambucil concentrations in plasma were measured by HPLC over a period of 24 h after drug intake. The peak concentration (Cmax) occurred earlier after administration of capsules than after administration of tablets [median (range)]: 0.50 (0.33-0.66) h vs 2.00 (0.66-4.00) h (p < 0.01). Although values of Cmax and the area under the plasma concentration versus time curve (AUC) were not significantly different, the two formulations were not bioequivalent. Tolerance was in both cases acceptable, with only a transient decrease in haemoglobin one day after last drug intake. The variability of chlorambucil pharmacokinetics tended to be less important for capsules than for tablets: 38% vs 71% and 35% vs 113% for Cmax and AUC respectively. Capsules are therefore likely to be more reliable than tablets for clinical use.

Aged↗
PubMed1994

Tumor necrosis factor alpha (TNF alpha) downregulates c-kit proto-oncogene product expression in normal and acute myeloid leukemia CD34+ cells via p55 TNF alpha receptors.

Tumor necrosis factor alpha (TNF alpha), as a modulator of hematopoiesis, interacts with many growth factor receptors, such as interleukin-3, granulocyte-macrophage colony-stimulating factor (CSF), and granulocyte-CSF receptors. Here, we studied the interactions between TNF alpha and the stem cell factor (SCF) receptor, c-kit, in normal CD34+ hematopoietic progenitors and their leukemic counterpart, ie, acute myeloid leukemic (AML) CD34+ cells coexpressing c-kit antigen. The results showed that (1) incubation of normal bone marrow mononuclear cells with 200 U/mL rhTNF alpha for 20 hours induced a diminution of 31.2% +/- 5.2% of CD34+ cells coexpressing c-kit; (2) the same decrease was observed using purified CD34+ cells and, furthermore, their proliferative response to SCF was inhibited by 31.5% +/- 7.3% after exposure to TNF alpha; (3) similar experiments performed on CD34+ c-kit+ AML cells from 11 patients gave comparable results. Further analysis at the mRNA level indicated that TNF alpha decreased c-kit mRNA transcripts. Moreover, using monoclonal antibodies against the two types of TNF alpha receptors, p75 and p55, we showed that the downregulation of c-kit proto-oncogene product by TNF alpha, on normal and leukemic CD34+ cells, was exclusively mediated by the TNF alpha p55 receptor. Therefore, we conclude that TNF alpha acts as a downregulator of the SCF receptor expression.

Adult↗
PubMed1994

Efficacy of recombinant human erythropoietin in the treatment of refractory anemias without excess of blasts in myelodysplastic syndromes.

To determine the efficacy of recombinant human erythropoietin at pharmacological doses in myelodysplastic syndromes (MDS) without excess of blasts, 20 patients with refractory anemias (RA) or refractory anemias with ring sideroblasts (RARS) were treated in an open study with escalating doses from 40 U/kg to 300 U/kg three times a week subcutaneously during a period of 3 months. Maintenance therapy at the lowest effective dose was continued in responders. A dose response of CFU-E and BFU-E to Epo was analysed at the entry. Bone marrow examination with an in vitro study of hematopoietic progenitors was performed before and after the first three months. Seven of 20 patients responded: a total recovery was observed in 3 patients; one became transfusion independent and a reduction of 50% of the transfusion requirement was achieved in 3 others. 3 patients are still receiving treatment for 2, 3 and 4 years. No significant correlation was found between the in vitro and clinical response. A non parametric analysis of responders and non responders emphasised the importance of a long delay between the diagnosis and the treatment, (p = 0.024) and an endogenous Epo level less than 100 mU/ml (p = 0.025) in order to predict the efficacy of rhEpo. This study offers evidence that patients with refractory anemias without excess of blasts in the bone marrow respond to rhEpo at pharmacological doses. Larger studies are required in order to define the patients who may respond and to elucidate the mechanism of the positive effect of rhEpo.

Adult↗
PubMed1994

Bone marrow protection.

During the Third International Conference on Negative Control of Hematopoiesis (Paris, April 1993), a special session was devoted to bone marrow protection. Myelotoxicity is often a limiting factor in the use of efficient doses of chemo- or radiotherapy. It appeared therefore of great importance to protect hematopoietic stem cells in order to allow the restoration of hematopoiesis and to prevent the occurrence of lethal aplasia. Several approaches to decrease the myelotoxicity of chemo- and/or radiotherapy were discussed: MDR gene therapy, use of chemical compounds (AS101, WR 2721), cytokines such as TNF alpha and IL-1 and small peptides, pEEDCK and AcSKDP. Interestingly, several of these molecules appear of interest to protect normal stem cells during marrow purging for autograft.

Amino Acid Sequence↗
PubMed1994

In vivo effects of GM-CSF and IL-3 on hematopoietic cell recovery in bone marrow and blood after autologous transplantation with mafosfamide-purged marrow in lymphoid malignancies.

This retrospective study evaluates the impact of GM-CSF and interleukin 3 (IL-3) on bone marrow (BM) and peripheral blood (PB) cell recovery following autologous bone marrow transplantation (ABMT) with mafosfamide-purged BM in patients with lymphoid malignancies compared with a control group receiving no colony-stimulating factor. GM-CSF was administered at 250 micrograms/m2/day (8 patients) as a continuous infusion from day of autologous BMT until the absolute neutrophil count (ANC) reached 0.5 x 10(9)/l for 7 days or until day 30, whichever was first. IL-3 was administered daily starting on the first day of transplant at a dose of 1 microgram/kg/day (6 patients) and 5 micrograms/kg/day (6 patients) for 30 days. CFU-GM and BFU-E were sequentially evaluated in BM and PB at days 7, 14, 21, 28, and 56 post-graft. The neutrophil recovery (ANC > 0.5 x 10(9)/l) was significantly faster in the GM-CSF group compared with IL-3 5 micrograms, IL-3 1 microgram and control group (respectively, days 15, 21, 22, 24) (p < 0.05 to p < 0.01). Similarly, leukocyte recovery was faster in the GM-CSF group compared with control and IL-3 1 microgram groups (p < 0.01 and p < 0.05). No difference was noticed between the two IL-3 groups. Although no difference was observed in platelet recoveries (> 50 x 10(9)/l), it appeared that the GM-CSF group required more units of platelets than either the IL-3 1 microgram or 5 micrograms groups (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Direct and reversible inhibitory effect of the tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (Seraspenide) on the growth of human CD34+ subpopulations in response to growth factors.

The tetrapeptide Acetyl-N-Ser-Asp-Lys-Pro (AcSDKP, Seraspenide; Ipsen-Biotech, Paris, France), an inhibitor of murine spleen colony-forming units reduces the number and the percentage in DNA synthesis of progenitors from human unfractionated bone marrow. To determine whether AcSDKP may directly affect the growth potential of purified progenitors even at the most primitive level, CD34+HLA-DRhigh and CD34++HLA-DRlow cells were highly purified by cell sorting. Then, CD34+ subsets were stimulated in liquid culture with combinations of growth factors (GFs) and AcSDKP was added for 20 hours or 6 days and cells plated in methylcellulose. After a 20-hour incubation, we show that AcSDKP (at 10(-10) mol/L) significantly inhibits the colony formation of both CD34+ subsets. Moreover, when added daily for 6 days, AcSDKP: (1) reduces the proliferation of both CD34+ cell fractions stimulated by 3 or 7 GFs, and (2) decreases the number of progenitors generated from the CD34+HLA-DRhigh and CD34++HLA-DRlow cell fractions. Furthermore, we show for the first time, using both high proliferative potential cell and long-term culture initiating cell assays, that AcSDKP inhibits the most primitive cells contained in the CD34++HLA-DRlow subpopulation. Finally, by using limiting dilution assays we demonstrated that AcSDKP acts directly at a single cell level and that its inhibitory effect is reversible and dose dependent.

Amino Acid Sequence↗