Search PubMed⌕ Search

Biomedical subjects

R Hast

Publications and source records attributed to R Hast.

At least 19 recordsLinked to original sources
PubMed2001

Long-term follow-up of 18 patients with myelodysplastic syndromes responding to recombinant erythropoietin treatment.

The outcome of continued EPO therapy was studied in 18 responding MDS patients. The EPO dose was reduced in a stepwise fashion to find the lowest possible maintenance dose. Relapses of anemia were associated with either progressive disease or reduction of the administered EPO dose. In the latter group second responses to renewed EPO therapy were readily achieved. Long-term responses were seen in about a third of the patients. Thus, it seems safe to reduce the EPO dose among responding patients. This approach may have advantages both from a medical and a socio-economic perspective.

Aged↗
PubMed2001

Masked monosomy 7 in myelodysplastic syndromes is uncommon and of undetermined clinical significance.

Masked monosomy 7, i.e. detected by FISH but not by conventional cytogenetics, has been reported in varying frequency in MDS. To establish the prevalence and possible clinical significance of the aberration, we studied the 123 previously karyotyped MDS patients using FISH and a DNA probe specific for chromosome 7. Metaphase cytogenetics revealed ten patients (8%) with monosomy 7 (6 RAEB and 4 RAEB-t). FISH confirmed this result and detected four more cases (4%) with masked monosomy 7 (3 RA and 1 RARS). Thus, masked monosomy 7 is less common than has been suggested, and does not seem to carry the same prognostic weight as monosomy 7 diagnosed by metaphase cytogenetics.

Adult↗
PubMed2001

Sequential fluorescence in situ hybridization analyses for trisomy 12 in chronic leukemic B-cell disorders.

BACKGROUND AND OBJECTIVES: Trisomy 12 is one of the most common chromosomal abnormalities in B-cell chronic lymphocytic leukemia (CLL). The aberration is readily detected by fluorescence in situ hybridization (FISH). There are only a few reports in which FISH analyses have been used to study the expansion of the trisomy 12 clone over time. DESIGN AND METHODS: Repeat FISH analyses were performed in 77 patients with a chronic leukemic B-cell disorder. The aim was to study the development of the trisomy 12 clone throughout the course of the disease, to measure the effect of therapy on the proportion of trisomic cells, and to relate the findings to the response to therapy. RESULTS: Fifty-eight of the 60 patients with no trisomy 12 at the initial test were consistently disomic for chromosome 12, while 2 patients seemingly acquired trisomy 12 during follow-up. Seventeen patients showed trisomy 12 at the first test. Expansion of the trisomy 12 clone was seen in all patients with a progressive lymphocytosis. In contrast to poor responders, patients responding well to chemotherapy showed a significant decrease in the proportion of CD19+ cells with trisomy 12. The effect of purine analogs in patients with trisomy 12 seemed inferior, both clinically and when studying the effect on the trisomic clone. INTERPRETATIONS AND CONCLUSIONS: There is a strong association between expansion of the trisomy 12 clone and progressive disease, both in treated and untreated patients. Conversely, reduction of the trisomic B-cell clone was linked to clinical response to chemotherapy. Acquisition of trisomy 12 remains a rare event.

Antineoplastic Agents↗
PubMed2000

Isolation and characterization of hematopoietic progenitor/stem cells in 5q-deleted myelodysplastic syndromes: evidence for involvement at the hematopoietic stem cell level.

Myelodysplastic syndromes (MDS) are a heterogeneous group of clonal disorders characterized by ineffective hematopoiesis and frequent progression to acute myeloid leukemia. Within MDS, 5q- syndrome constitutes a distinct clinical entity characterized by an isolated deletion of the long arm of chromosome 5 (5q-), a relatively good prognosis, and infrequent transformation to acute leukemia. The cell of origin in 5q- syndrome as well as in other 5q-deleted MDS patients has not been established, but evidence for involvement of multiple myeloid (but not lymphoid) lineages has suggested that a myeloid-restricted progenitor rather than a pluripotent (lympho-myeloid) stem cell might be the primary target in most patients. Although in 9 patients no evidence of peripheral blood T-cell and only 1 case of B-cell involvement was found, the data herein support that 5q deletions occur in hematopoietic stem cells (HSCs) with a combined lympho-myeloid potential. First, in all investigated patients a minimum of 94% of cells in the minor CD34(+)CD38(-) HSC compartment were 5q deleted as determined by fluorescence in situ hybridization. Second, in 3 of 5 patients 5q aberrations were detected in a large fraction (25% to 90%) of purified CD34(+)CD19(+) pro-B cells. Furthermore, extensive functional characterization with regard to responsiveness to early-acting cytokines, long-term culture-initiating cells, and nonobese diabetic/severe combined immunodeficiency repopulating cells supported that MDS HSCs in 5q-deleted patients are CD34(+)CD38(-), but inefficient at reconstituting hematopoiesis.

Antigens, CD34↗
PubMed2000

Atypical lymphocytes in B-cell chronic lymphocytic leukemia and trisomy 12 studied by conventional staining combined with fluorescence in situ hybridization.

Trisomy 12 is one of the most frequent chromosomal abnormalities in B-cell chronic lymphocytic leukemia (CLL), and is predominantly found in CLL with atypical morphology (aCLL). It has been suggested that the atypical morphology might be a feature of the abnormal trisomy 12 clone, but so far it has been difficult to allocate chromosomal aberrations to individual leukemic cells identified by cytomorphology. We therefore wanted to use our MGG/FISH method, which combines fluorescence in situ hybridization (FISH) and standard cytomorphology, to study if the trisomy 12 clone in CLL was restricted to lymphocytes with atypical morphology. Peripheral blood specimens of four patients with aCLL were studied using a DNA probe against the pericentromeric region of chromosome 12. Trisomy 12 was found in 10-34 % of the lymphocytes. In three patients, the proportion of atypical and typical lymphocytes with trisomy 12 was quite comparable, and so was the percentage of atypical cells with lymphoplasmacytoid morphology and those with cleaved nucleus showing trisomy 12. Only one patient differed, since we found an overrepresentation of trisomy 12 among the atypical lymphocytes. However, this could be fully explained by the diluting effect of contaminating T-cells after chemotherapy. The results of the present study show that despite the strong association of trisomy 12 and atypical morphology in CLL, this chromosomal abnormality is not confined to lymphocytes with atypical morphology, but is also found in typical CLL cells. This supports that both cell types have the same clonal origin and that different cell morphology cannot be explained alone by the acquisition of an additional chromosome 12.

Aged↗
PubMed1999

Neutrophil dysplasia is not a specific feature of the abnormal chromosomal clone in myelodysplastic syndromes.

In order to study if dysplastic cells are part of the abnormal chromosomal clone in myelodysplastic syndromes (MDS) we used fluorescence in situ hybridization in combination with standard May-Grünwald-Giemsa morphology (MGG/FISH) to investigate the penetration of chromosomal abnormalities into dysplastic neutrophil granulocytes in five MDS patients with documented monosomy 7 or trisomy 8 in the bone marrow at diagnosis. Neutrophil dysplasia was defined as neutrophil granulocytes with extreme hypogranulation or with nuclear abnormalities of the pelgeroid type. In one patient all dysplastic cells were derived from the abnormal chromosomal clone, while in the other four cases only 6-43% of the hypogranulated neutrophils and 33-40% of the pelgeroid granulocytes exhibited the chromosomal marker. The results suggest that neutrophil dysplasia is not a specific feature of the abnormal chromosomal clone in MDS. It is not clear, however, if the disomic dysplastic cells were derived from a parallel MDS clone with a normal karyotype, or represent residual non-clonal, normal hematopoietic cells.

Aged↗
PubMed1999

DNA image cytometry in MDS bone marrow smears.

The nuclear DNA content, defined as DNA index (DI) in blasts/promyelocytes (bla/pro), were determined on Feulgen-stained bone marrow smears from 39 patients with myelodysplastic syndromes (MDS) and eight control subjects by the use of image cytometry (ICM). The DI in patients was compared to that of corresponding normal cell types, and to cytogenetic data available in 32/39 patients. The mean DI in bla/pro of patients with MDS was significantly (P < 0.01) lower compared to corresponding cell types in control subjects. By ICM, a DNA aneuploidy in bla/pro was found in 67% of the MDS patients, and 59% expressed DNA hypodiploidy. By cytogenetics, an abnormal karyotype was found in 31%, and 6/9 MDS patients with a 'hypodiploid' abnormal karyotype showed DNA hypodiploidy. Of patients with a normal karyotype (69%), seven (32%) showed a normal, 12 (55%) a lower, and three (14%) a higher DI compared to controls. No difference between groups of MDS patients was found. DNA hypodiploidy is suggested to be a common feature in MDS without a relationship to cytogenetics.

Adult↗
PubMed1999

Successful treatment with fludarabine in two cases of angioimmunoblastic lymphadenopathy with dysproteinemia.

Angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) is today recognized as a T-cell lymphoma which in most cases runs an aggressive course. The diagnosis is often difficult because of the varying clinico-pathological picture. Less than a third of the patients can be expected to have long-term remissions even after multiagent chemotherapy. Complete remissions have been reported after the use of interferon-alpha, cyclosporin A, and recently purine analogues in a few patients. We now report two cases of AILD that had unmaintained remissions for 32 and 10 months, respectively, after fludarabine therapy. In one of the patients fludarabine was used up-front and in the other after she had proved to be resistant to CHOP treatment. No severe infectious complications were noted. The use of purine analogues should be investigated further in AILD.

Aged↗
PubMed1998

Gain of chromosome 7 marks the progression from indolent to aggressive follicle centre lymphoma and is a common finding in patients with diffuse large B-cell lymphoma: a study by FISH.

Gain of chromosome 7 represents one of the most frequent cytogenetic findings in B-cell lymphomas with a follicular growth pattern. We used fluorescence in situ hybridization (FISH) and a probe specifying chromosome 7 on lymph node imprints and/or bone marrow (BM) and peripheral blood (PB) smears from six consecutive patients with follicle centre lymphomas (FCLs) grade I or II (low-grade lymphomas), four patients with FCLs grade III and 11 patients with diffuse large B-cell lymphomas (DLBCLs) (high-grade lymphomas). We found gains of chromosome 7 in 14/18 successfully analysed cases (i.e. 2/6 FCLs grade I-II, 3/3 FLCs grade III and in 9/9 DLBCLs) using lymph node imprints. Moreover, the FISH technique demonstrated gains of chromosome 7 in 1/4 BM and 0/4 PB samples from FCLs grade I-II, in 2/4 BM and 2/4 PB specimens from FCLs grade III and in 4/9 BM and 2/9 PB samples from the DLBCLs. In contrast, morphologically recognizable lymphoma cells were seen in only 1/4 BM and 0/4 PB samples from the FCLs grade III and in 1/11 BM and 1/11 PB samples from the DLBCLs. We conclude that: (i) gain of chromosome 7 marks the progression from indolent to aggressive FCL and would appear to be a common finding in patients with FCLs grade III and in DLBCLs, (ii) clonal lymphoid cells occur frequently in BM and PB in high-grade lymphomas, making traditional staging by cytomorphology uncertain, and (iii) using gains of chromosome 7 as a marker of lymphoma cells, FISH is a useful method to detect minimal residual disease in FCLs grade III and DLBCLs.

Adult↗
PubMed1998

Trisomy 12 and lymphoplasmacytoid lymphocytes in chronic leukemic B-cell disorders.

BACKGROUND AND OBJECTIVE: Although the finding of trisomy 12 in B-cell malignancies has been extensively documented especially in B-CLL, little is known about the clonal involvement of different tissues and there are few sequential studies documenting the development of trisomy 12 during the course of the disease. The aim of this study was, therefore, to: 1) ascertain the prevalence of trisomy 12 by FISH; 2) correlate the findings of trisomy 12 with hematologic and clinical features; 3) study the trisomy 12 positive clone during the course of the disease, and 4) compare findings of trisomy 12 in different tissues. DESIGN AND METHODS: This a study of an unselected population of 118 patients with CLL or other B-cell disorders in leukemic phase from a defined geographic area. Trisomy 12 was detected by FISH. RESULTS: Trisomy 12 was found in 18 patients (15%). The aberration was significantly more common in morphologically atypical CLL (aCLL) (24%) and CLL/PL (67%) compared to typical CLL (2%) (p < 0.001). aCLL cases had predominantly lymphocytes with lymphoplasmacytoid features. Sequential studies of peripheral blood showed an increase in the proportion of trisomic cells during the observation time, mostly associated with disease progression. None of the initially trisomy 12 negative patients acquired the aberration during follow-up. The percentage of lymphocytes exhibiting trisomy 12 was significantly (p < 0.05) higher in the bone marrow than in peripheral blood. INTERPRETATION AND CONCLUSIONS: Trisomy 12 might define a distinct disease entity with atypical lymphocytes in chronic leukemic B-cell disorders.

Aged↗
PubMed1997

[PNH--paroxysmal nocturnal hemoglobinuria. An old disease explained by new technology].

The review outlines developments in research on paroxysmal nocturnal haemoglobinuria (PNH). The disease is due to a somatic mutation of the PIG-A gene. This results in deficiency of the protein, GPI (glucosyl phosphatidyl inositol), which serves as an anchor for several membrane-bound proteins including MIRL (CD59; membrane inhibitor of reactive lysis) and DAF (CD55; decay accelerating factor). The absence of these proteins results in increased cellular sensitivity to complement-mediated lysis, affecting not only red cells, leukocytes and platelets, but also haemopoietic stem cells. This explains the often complex clinical picture in PNH (haemolysis, pancytopenia and increased thrombotic predisposition), and the well known relationship between PNH and aplastic anaemia.

Hemoglobinuria, Paroxysmal↗
PubMed1997

Plasma pharmacokinetics of idarubicin and its 13-dihydro metabolite--a comparison of bolus versus 2 h infusion during a 3 day course.

The plasma pharmacokinetics of a second generation anthracycline derivative, idarubicin (Ida), have been studied in 17 patients with acute myelocytic leukemia (AML) and high risk features. The drug (10 mg/m2) was given in a randomized cross-over design as 3 min and 2 h infusions for three consecutive days. Cytosine arabinoside (Ara-C, 1 g/m2) was given on days 1-4. The plasma concentration time course of Ida was most properly described by the three-compartment pharmacokinetic model, independent of administration time. The maximum plasma concentration (Cmax) of Ida was reduced by a factor of 3 by increasing the infusion time from 3 min to 2 h. The pharmacokinetic pattern of the active metabolite idarubicinol (IdaOH) was only to a minor extent affected by the longer infusion time. The time course of IdaOH following each dose of Ida was accurately described by the one-compartment model with a first-order formation phase. The are under the plasma concentration versus time curves (AUC) of Ida and IdaOH were not affected by the administration time. Following Ida in combination with Ara-C, the medial duration of leukopenia (< 1.0 x 10(9)/l) was 14 days (range 5-56) and of thrombocytopenia (< 50 x 10(9)/l) was 22 days (range 7-120). The large majority of patients developed infectious complications. Two patients with MDS-AML showed a good response. The results of the present study give no evidence of reduced hematologic toxicity by increasing the administration time of Ida from 3 min to 2 h. However, minimizing Cmax, by administration of Ida as prolonged infusion during a 3 day course, might be clinically important in order to reduce cardiotoxicity and hopefully to increase anti-tumor efficacy through an increased accumulation of Ida and IdaOH in leukemic cells.

Aged↗
PubMed1997

Differences in cell lineage involvement between MDS-AML and de novo AML studied by fluorescence in situ hybridization in combination with morphology.

We have employed fluorescence in situ hybridization (FISH) in combination with standard morphology (MGG/FISH) to identify the clonal involvement of different bone marrow cell lineages in 20 AML patients (14 MDS-AML, 6 de novo AML). Even though the number of cells belonging to the abnormal clone varied between individual cases, the percentage of clonal blasts was similar in MDS-AML and de novo AML patients. The erythropoietic cells appeared to be part of the abnormal clone in 13 of 14 patients with MDS-AML, but only in 1 of 6 with de novo AML. Similarly, clonal granulocytes were detected in 13 of 14 patients with MDS-AML, compared to 2 of 6 with de novo AML. Lymphocytes consistently displayed normal, diploid karyotype. The results suggest that it is possible to distinguish between MDS-AML and de novo AML by the use of MGG/FISH; in de novo AML the abnormal chromosomal clone is generally confined to the immature myeloid cells, while in MDS-AML mature granulocytes and erythroid cells are of clonal origin. It is, however, not possible to conclude that MDS-AML is a "multipotent" type of leukaemia, since it cannot be ruled out that the chromosomally aberrant erythroid cells and granulocytes represent surviving cells from the original MDS clone.

Adult↗
PubMed1996

A sequential erythropoietin and GM-CSF schedule offers clinical benefits in the treatment of anaemia in myelodysplastic syndromes.

In order to reduce anaemia in patients with myelodysplastic syndromes (MDS) a stepwise treatment protocol including erythropoietin (EP) and granulocyte-macrophage colony-stimulating factor (GM-CSF) was designed. Thirty-seven MDS patients (stages I-III) with symptomatic anaemia were first given EPO 10,000 U s.c. 3 times weekly for 6 weeks. Those not responding, i.e. increased their haemoglobin levels > 15 g/l, proceeded into the second phase of the study where GM-CSF (200 micrograms/d. s.c. on weeks 1-6) was combined with EPO (10,000 U s.c. 3 times weekly on weeks 5-14). Following the initial EPO treatment phase, 14 of the 37 patients (38%) responded with increased haemoglobin levels. Responders were significantly different from non-responders in that their pre-treatment values of s-EPO, s-LDH and bone marrow blast cell counts were lower, their baseline haemoglobin levels higher and their transfusion dependency less pronounced. Eighteen of the 23 non-responders proceeded into the second phase, 13 of those were evaluable having completed the entire schedule. Three of the 13 initially EPO resistant patients (23%) responded to the GM-CSF/EPO combination with increased haemoglobin levels, suggesting a positive synergy between the two cytokines. Thus, the overall response rate to the present protocol was 46% (17 of 37 cases), but only a limited subset of the patients did clearly benefit from the combined GM-CSF/EPO administration. Therefore, we believe this step-wise approach to multiple growth factor treatment in MDS, starting with EPO alone and reserving the combination for refractory cases, has considerable advantages, taking into account both medical and socio-economical aspects.

Aged↗
PubMed1996

Fluorescence in situ hybridization in combination with morphology detects minimal residual disease in remission and heralds relapse in acute leukaemia.

Fluorescence in situ hybridization in combination with morphology (MGG/FISH) was used to detect minimal residual disease (MRD) in complete remission (CR) in 12 cases of acute leukaemia (six MDS-AML, five de novo AML, one pre-B ALL) with numerical chromosomal aberrations at diagnosis. Residual leukaemic cells could be detected in the remission bone marrows by MGG/FISH in five patients, whereas the other seven showed no abnormalities. All five patients with signs of MRD at CR relapsed in the bone marrow with 2-9 months, in contrast to two of seven with a normal finding by MGG/FISH at CR. In both these patients a second MGG/FISH analysis showed that a subpopulation of leukaemic blasts had reappeared, 4 and 5 months prior to the leukaemia becoming clinically overt. One patient suffered a CNS relapse, but without any evidence of bone marrow involvement. The remaining four patients with no evidence of MRD at CR were still in haematological remission at follow-up after 4, 11, 12 and 13 months, respectively. We conclude that MGG/FISH seems to be a clinically useful method to detect MRD in acute leukaemia and to predict relapses, particularly when repeat studies are performed during CR.

Adult↗