Biomedical subjects

H Kabisch

Publications and source records attributed to H Kabisch.

90 records · Page 5Linked to original sources

PubMedDate not supplied

[Minimal residual disease analysis in acute lymphoblastic leukemia of childhood within the framework of COALL Study: results of an induction therapy without asparaginase].

UNLABELLED: The detection of minimal residual disease (MRD) is a major prognostic factor for treatment in acute lymphoblastic leukemia (ALL) of childhood. Several groups showed the predictive value of MRD after 5 weeks of chemotherapy (at the end of induction therapy). Patients with more than 1 leukemic cells in 100 cells (> or = 10(-2)) at this time-point have a significantly higher relapse rate. The MRD measurement has been shown to be an independent prognostic factor at several time points in the BFM study (ALL-BFM 90) as well as in the EORTC study. The aim of our investigations was the detection of MRD at the end of induction therapy within the COALL studies which is different from the above studies. In the COALL studies, therapy starts with a 1 week DNR prephase (24 h infusion on day one) and i.th. MTX. Induction therapy consisted of 3 drugs over a period of 4 weeks (Prednisolone, Vincristine and Daunorubicin), asparaginase is given later in consolidation. At the end of induction therapy, bone marrow was obtained for cytomorphologic and molecular analysis. PATIENTS AND METHODS: We investigated bone marrow samples from 76 patients. All patients were in morphologic remission at the end. of induction therapy. For MRD analysis, DNA was isolated from bone marrow mononuclear cells. Clonal T-cell-receptor (TCR) or immunoglobulin gene (IgH) rearrangements were identified by PCR. Monoclonal products were either sequenced directly (TCR) or after excision from high resolution agarose gels. Subsequently patient-specific oligonucleotides for allele-specific PCR were generated. PCR analysis was performed with 1 microgram DNA for each reaction within a semiquantitative matter. This method reached sensitivities down to 10(-5). RESULTS: Eighty-four percent of the analysed samples were MRD positive at the end of induction therapy. 20 out of 76 patient samples (26%) were highly positive (> or = 10(-2)), 28 patients had levels of about 10(-3) (37%), 16 had levels around 10(-4) (21%) and 12 patients had no detectable residual cells (16%). All analysed 15 T-ALL patients had detectable residual disease at this timepoint. Until now, 5/20 patients with very high MRD level at the end of induction therapy suffered a relapse. DISCUSSION: Patients with very high MRD level at the end of induction therapy showed an elevated risk of relapse, but the predictive value is much poorer than for example in the BFM 90 MRD-study. We suggest, that a high MRD level at this timepoint results from a different induction therapy compared to the BFM 90 study. In the COALL studies asparaginase is given only after induction therapy to decrease the risk of thrombosis. We would like to conclude that this differences were compensated later during therapy as the event free survival of both studies is similar. In conclusion, an optimal information from MRD studies is strongly associated with the given therapy. Therefore we initiated an additional MRD time-point after the first chemotherapy block in consolidation.

Antineoplastic Combined Chemotherapy Protocols↗

PubMedDate not supplied

[Improved treatment results in children with AML: Results of study AML-BFM 93].

BACKGROUND: In the multicenter trial AML-BFM 93 daunorubicin or idarubicin was randomly applied in all patients during induction in combination with cytarabine and etoposide. After induction all patients were stratified to the standard or high risk group. To improve outcome in high risk patients high dose cytarabine and mitoxantrone (HAM) was introduced. The placing of HAM as either the 2nd or 3rd therapy block was randomized to evaluate the efficacy and toxicity accordingly. PATIENTS AND METHODS: 471 children with de novo AML entered the trial AML-BFM 93 (161 standard risk, 310 high risk). RESULTS: Overall, 387 of 471 (82 %) patients achieved remission, 5-year survival, event free survival (EFS), and disease free survival were 60 % SE 3 %, 51 % SE 2 % and 62 % SE 3 %, respectively. Idarubicin-based induction resulted in a significantly better blast cell reduction in the bone marrow on day 15 (25 of 144=17 % patients with > 5 % blasts compared to 46 of 149=31 % patients after daunorubicin, pchi(2)=0.01). This was, however, mainly seen in high risk patients treated with idarubicin (19 % vs. 38 %, pchi(2)=0.007). Cardiotoxicity, WHO grade 1 - 3 shortening fraction reduction after induction occurred in 6 % patients in both arms. In the total group of patients probabilities of five years event-free survival and disease-free survival were similar for patients treated with daunorubicin or idarubicin. However, in patients presenting with more than 5 % blasts on day 15 there was a trend for a better outcome after treatment with idarubicin (p logrank 0.06). Outcome in high risk patients was superior in study 93 compared to study 87 (remission rate and 5-year pEFS in study AML-BFM 93 vs. study 87: 78 % vs. 68 %, p=0.007, and 44 % vs. 31 %, p logrank=0.01). The placing of HAM as the 2nd or 3rd therapy block was of minor importance. However, patients who received the daunorubicin treatment during induction benefited from early HAM. CONCLUSION: Compared to study AML-BFM 87 treatment results in study AML 93 improved significantly in high risk patients. This can partly be contributed to the better response on day 15 after idarubicin induction but is mainly due to the introduction of HAM.

Acute Disease↗

PubMedDate not supplied

[Unrelated donor stem cell transplantation in children: low toxicity using a GvHD-prophylaxis regimen with CSA, MTX, metronidazole,iv-immunoglobulin and ATG].

BACKGROUND: Unrelated donor (UD) hematopoietic stem cell transplantation (HSCT) is accepted as a therapy for leukaemic diseases and varying inborn diseases if a suitable related donor cannot be found. The goal of immunosuppressive therapy with UD-HSCT is an effective prevention of graft-versus-host-disease (GvHD) on one hand. On the other hand an optimal balance with immunocompetence of the transplanted bone marrow is desirable in order to prevent graft failure, infection and, in the case of leukaemic diseases, potentially control the underlying disease. PATIENTS AND METHODS: Between 1992 and 2000 49 patients aged 11 months to 16.7 years received an UD-HSCT in Hamburg. Underlying diseases were leukaemia or MDS in 35, of these ALL in 21, hemophagocytic lymphohistiocytosis (HLH) in 9, immunodeficiency or inborn error of metabolism in 5 patients. GvHD-prophylaxis consisted of a combination of Cyclosporin A (CSA), methotrexate (MTX), metronidazole, IgM-enriched iv-immunoglobulin (ivIg) (Pentaglobin(R)) or ivIgG and anti-thymocyte-globulin (ATG). Within the same time span 10 patients with ALL received a matched related donor HSCT (MRD-HSCT). GvHD-prophylaxis in these patients was done without ATG in 8 of 10 cases. UD-HSCT were analyzed for survival, relapse and toxicity. Probability of survival of the patients with ALL after UD-HSCT was compared with results of MRD-HSCT in children with ALL. RESULTS: The Kaplan-Meier estimates of three year overall-survival (OS) were 74 % for all patients. Probability of disease-free survival (DFS) at three years was 62 % for leukaemia/MDS-patients and 100 % for the HLH-patients. Acute GvHD (aGvHD) grades II or III occurred in 51 % of patients. Chronic GvHD (cGvHD) occurred in 22 % of patients. There were 5 cases of treatment-related mortality (TRM). Probability of DFS for patients with ALL at three years was 65 % after UD-HSCT and 30 % in the patients after MRD-HSCT. CONCLUSIONS: UD-HSCT in children is an effective and safe therapy. A GvHD-prophylaxis regimen combining the standard immunosuppressive agents CSA and MTX with ivIg, metronidazole and serotherapy using ATG may result in a low incidence of severe GvHD-complications and low TRM rate without increase in relapse rates.

Adolescent↗

PubMedDate not supplied

[Effect of cranial irradiation on rate of recurrence in children with acute myeloid leukemia. Initial results of the AML-BFM-87 study. The AML-BFM Study Group].

Study AML-BFM-87 compared prospectively if cranial irradiation could be abandoned by adding two blocks of intensification with high dose ARA-C and VP-16 after consolidation and furthermore, improve prognosis compared to study -83. 210 children were enrolled in study AML-BFM-87 until March 31, 1991. 164 (78%) achieved complete remission. Probabilities for event-free survival (EFS) and event-free interval (EFI) of 5 years were: .45 (SD .04) and .57 (SD .05). In the first 2.5 years of the study irradiation was randomized (n = 31), selected or refused (n = 24). However, during this period irradiation was mandatory in patients with leukocyte count greater than 70,000/mm3, and also in children with initial CNS involvement. Since July 1989 prophylactic cranial irradiation was abandoned. Patients of the group with mandatory irradiation (n = 39) presented with more unfavourable risk parameters than the group of non-irradiated children, who were enrolled in the study after randomisation had been stopped. Nevertheless, results showed in randomized and selected patient groups as well as in the total cohort a longer relapse-free interval (RFI) in irradiated (n = 66) compared to non-irradiated (n = 94) patients (RFI of 5 years: .70, SD .04 vs. .51, SD .07, p less than .05). Relapses in non-irradiated children occurred mainly in the bone marrow and less often in the CNS. The increase in relapse rate was seen especially in non-irradiated patients of the low risk group as defined in study AML-BFM-83 (RFI: .40, SD .14 vs. .79, SD .09 with irradiation, p less than .01). In the high risk group, however, the differences were not significant. Our results suggest that cranial irradiation is an important part of therapy in childhood AML, and that the good prognosis of the low risk group in study AML-BFM-83 was probably based on the combination of intensive chemotherapy and cranial irradiation.

Antineoplastic Combined Chemotherapy Protocols↗

PubMedDate not supplied

[Treatment of recurrence of acute myeloid leukemia in childhood. A retrospective analysis of recurrence in the AML-BFM-83 study].

Complete remission (CR) rates of 80% are achieved with the AML-BFM protocols but one third of patients relapse within the first three years. There are few reports of treatment of relapsed childhood AML, and these deal with the evaluation of new drugs for frontline therapy. We performed a retrospective analysis to investigate how patients previously treated with the AML-BFM-83 protocol were treated after relapse and how many long term remissions were achieved. 48 of 139 patients relapsed after having achieved complete remission with the AML-BFM-83 protocol which consists of continous infusion of ARA-C 100 mg/m2 day 1-2, ARA-C 200 mg/m2 day 3-8, Daunorubicin 60 mg/m2 day 3, 4, and 5, and VP-16 150 mg/m2 day 6, 7, and 8, and an 8 week consolidation therapy consisting of Prednisolone, Thioguanine, Vincristine, ADR, ARA-C, Cyclophosphamide, intrathecal ARA-C and cranial irradiation followed by maintenance therapy. Duration of first remission ranged from 1.5 months to 66.3 months. Excluding 5 children with either isolated or combined extramedullary relapses and another 4 patients for missing data, 39 children were evaluable. 20 children received no therapy or palliative therapy while 16 patients received chemotherapy and another 3 children were transplanted in relapse. Although 9 different intensive chemotherapy regimens were used for reinduction, a high number (12 of 16 = 75%) of second complete remissions was achieved. Several therapeutic options were used to maintain a second remission: regular maintenance therapy (7 patients), allogeneous bone marrow transplantation (BMT) (2 patients), autologous BMT (3 patients).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

[N-myc status of neuroblastoma from bone marrow cells].

The analysis of the N-myc gene in bone marrow specimens at the time of initial diagnosis and as well at the time of relapse from patients with Neuroblastoma stage IV and bone marrow infiltration could give some informations about the N-myc status of these patients. In stage IV neuroblastoma patients with bone marrow infiltration an estimation of the N-myc gene amplification should be attempted, if otherwise no information about the tumor content of the N-myc gene could be gathered. In our investigation we could demonstrate a Southern-blot-analysis of 27 bone marrow specimens with respect to the N-myc gene status which correlated qualitatively well to the N-myc amplification detected later on in the corresponding tumor tissue. In six cases the tumor infiltrated bone marrow showed a clear amplification of the N-myc gene. Because of the contamination by non malignant cells in bone marrow there was a quantitative difference in the calculated N-myc gene copies between the examined bone marrow specimens and corresponding tumor tissue.

Biopsy, Needle↗

PubMedDate not supplied

[Retinoblastoma gene analysis in a patient with osteosarcoma following previous bilateral retinoblastoma].

In a native osteosarcoma specimen of a patient cured of a bilateral retinoblastoma eight years before we found a homozygous deletion of a 7.5 kb Hind III-fragment within the retinoblastoma gene and a hemizygous deletion of the same fragment in its constitutional cells. In a native osteosarcoma tissue of a lung metastasis of a patient with sporadic osteosarcoma the Rb-gene-analysis did not reveal any deletion within the gene. This might be due to the fact that the used c-DNA-probe did not detect point mutations. Nevertheless, the possibility of additional or alternative transforming events should be kept in mind.

Brain Neoplasms↗

PubMedDate not supplied

[Combined treatment strategy in over 200 children with Hodgkin's disease: graduated chemotherapy, involved field irradiation with low dosage and selective splenectomy. A report of the cooperative therapy study DAL-HD-82].

UNLABELLED: It was the aim of the cooperative therapy study HD-82 for children with Hodgkin's disease to reduce chemo- and radiotherapy and to investigate of a strategy for selective splenectomy previously developed in the Hodgkin study HD-78. Between December 1981 and December 1984 207 patients (131 boys and 76 girls) below 16 years of age were enrolled in this study. In 174 out of 207 patients (84.1%) the criteria for selective splenectomy were applied i.e. the spleen was only removed when the splenic surface was nodular or when the lymphnodes at the splenic hilus and/or the pancreatic tail were enlarged. 69 out of 174 patients (39.7%) had a splenectomy. 50 of the removed 69 spleens (72%) showed histological evidence of Hodgkin's disease. These results were comparable to the 36% and 73% predicted from the retrospective analysis in the HD-78 study. According to the stage of Hodgkin's disease three different treatment groups with 2, 4 and 6 cycles of OPPA/COPP were formed (stage I/IIA, IIB/IIIA and IIIB/IV). Radiation therapy was given as involved field irradiation with a total dose of 35, 30 and 25 Gy depending on the extent of the chemotherapy. 203 patients were treated according to the protocol. Until the 30th of November 1985 3 patients died from intercurrent disease during a follow-up period of 11 to 47 months (median 29 months). 5 patients relapsed. The probability for disease-free survival after 3 1/2 years is 96% for the total group and 99%, 96% and 87% for the three treatment groups including 100, 53 and 50 patients in each group respectively. CONCLUSIONS: 1. The OPPA/COPP chemotherapy eliminates reliably occult microfoci. 2. The radiation doses in combination with the chemotherapy are sufficient to prevent local recurrences. 3. The decisional model for selective splenectomy has proved to be extremely valuable prospectively.

Adolescent↗

PubMedDate not supplied

[Cooperative therapy study of nontesticular germ cell tumors MAKEI 83 of the Society of Pediatric Oncology: analysis after 3 years].

The German Society of Pediatric Oncology has initiated in 1983 a cooperative trial for the treatment of extratesticular germ cell tumors. The treatment plan is stratified according to histology, tumor site and tumor extension. Patients with unfavourable histology received depending on prognostic factors 4 courses of either vinblastine, actinomycin D and cyclophosphamide, or the combination of vinblastine, bleomycin and cisplatinum (4 courses) completed by 4 additional courses of VP 16, ifosfamide and cisplatinum. Within 3 years, 115 patients from 37 different institutions were entered into the trial. 55 of 72 protocol patients are under observation for at least 10 months since diagnosis. The disease-free survival rate according to Kaplan-Meier is 80% (+/- 6%) at 36 months. From the interim results of this ongoing study, the following conclusions are drawn: The chemotherapeutic regimens as delivered are tolerable. Radiotherapy does not seem necessary with the exception of ovarian dysgerminomas stage I a. In coccygeal teratomas the resection of the coccygeal bone decreases the hazard of local recurrences. Using the risk adapted regimen, the prognosis for teratomas with Yolk sac origin appears as favourable as for patients with mature teratomas.

Adolescent↗

PubMedDate not supplied

[Adult form of chronic myelogenous leukemia in childhood--a retrospective analysis of 20 patients].

The initial findings and the course of 20 children and adolescents with adult CML from 10 children hospitals were analyzed retrospectively. The Philadelphia chromosome was found in 18 patients. Initial findings, the course and the prognosis were similar to those published from adult patients. 7 of the 11 children who received chemotherapy alone are still alive with a median survival time of 26 months (range: 14 to 68 months). One patient survived the third blast crisis. For 9 children with a bone marrow transplantation during the chronic phase (median time before transplantation 30 months) the follow-up of 7 months is still too short. 4 of these patients died following graft versus host reaction, 5 show no signs of a renewed occurrence of CML so far. Since CML is rare in children, there is little large scale experience. Hence, there is an urgent need for the prospective and cooperative study of these patients.

Adolescent↗

PubMedDate not supplied

[Acute myelogenous leukemia in children: results of the cooperative BFM-78 therapy study after 3 3/4 years].

Between December, 1978, and October, 1982, 151 children with acute myelogenous leukemia from 30 pediatric clinics entered the cooperative study. The treatment consisted of a 10-week intensive induction therapy and a subsequent maintenance therapy, which is terminated for children in complete continuous remission after 2 years. The induction treatment during the first 4 weeks consisted of a combination of prednisone, 6-thioguanine (TG), vincristine, adriamycin (ADR) and cytosine-arabinoside (ARA-C). In the following 4 weeks i.v. cyclophosphamide, i.th. methotrexate and prophylactic cranial irradiation were administered in addition to TG, ARA-C and ADR. 119 of the 151 patients (79%) achieved complete remission. 13 children (9%) died of early hemorrhages, 2 of them before onset of therapy. 5 patients died initially of other complications, another 6 after remission has been achieved. 13 children did not respond or responded poorly to the induction therapy. So far, 40 relapses occurred, mainly in the bone marrow. In 6 relapses the central nervous system was involved. The probability for a continuous complete remission for the total group is 0.41 +/- 0.05 (life table analysis) and for the total group 0.56 +/- 0.06 after 45 months. The corresponding probability for survival after 46 months are 0.43 +/- 0.06 for the remission group. The risk for occurrence of early fatal hemorrhages was higher in children with acute monocytic leukemia than in the other morphological subtypes. An initial leukocyte count of more than 100,000/microliters was found significantly more often in patients who did not achieve remission (early deaths and nonresponders) than in children of the remission group. So far, no factors could be identified which influence the risk for relapse. The present results of the study allow the conclusion, that with the applied treatment strategy it is possible to achieve not only in a high portion of children with AML remission but also to improve the chances for long-time remission and perhaps cure.

Adolescent↗

PubMedDate not supplied

[COALL-80 therapy in the management of acute lymphoblastic leukemia in childhood--an interim report].

In order to reduce the toxicity of the otherwise very effective childhood ALL treatment protocol BFM 76/79 asparaginase was omitted from the 4-drug induction regimen and placed as single drug before the intensification phase. In addition the effect of 3-monthly intermediate dose methotrexate (ID-MTX) pulses versus conventional vincristine (VCR) pulses during maintenance therapy was studied. Of 145 evaluable patients 124 (85.5%) survive in continuous and complete remission (CCR) at a median observation time of 21 (1,5-47) months. The expected rate of patients in CCR at 4 years is 75% respectively 80% after exclusion of 4 patients with fatal complications and one remission failure. These relapse free survival data re equal to the BFM 76/79 and 79/81 results. There was very few therapy related morbidity and no mortality from the COALL-80 induction therapy modification. The intensification phase, however, which was adopted from the BFM study without modification was difficult to manage and was not free of life threatening mostly infectious complications which were fatal in 4 cases. ID-MTX pulses did not prove superior to conventional VCR pulses. The relapse rate in patients with the c-ALL subtype was markedly lower than in any other subtype, remarkably also than in the undifferentiated type.

Adolescent↗

PubMedDate not supplied

[Reducing radiation dosage to 20-30 Gy in combined chemo-/radiotherapy of Hodgkin's disease in childhood. A report of the cooperative DAL-HD-87 therapy study].

UNLABELLED: The main objective of the multicenter study DAL-HD-87 was to evaluate for the involved-field irradiation a dose reduction by 5 Gy compared with the precursor studies HD-82 and HD-85. Moreover, the decisional strategy for selective laparotomy developed on the basis of retrospective analyses in study HD-82 was to be tested in a prospective design. Chemotherapy in group 1 (stages I, IIA) consisted in 2 OPA cycles (vincristine, prednisone, adriamycin). Group 2 (stages IIEA, IIB, IIIA) received 2 x OPA + 2 x COP(P), and group 3 (stages IIEB, IIIB, IV) 2 x OPPA (with procarbacine) + 4 x COP(P). For the subsequent radiotherapy, doses of 30, 25, and 20 Gy respectively were applied in the 3 groups. Fields with incomplete lymphoma regression were to receive an additional boost of 5-10 Gy. -Exploratory laparotomy was considered indicated in the event of abnormal findings in abdominal CT/ultrasonography and/or enlargement of lymph nodes at the pulmonary hilus. RESULTS: From Dec. 1986 to Sept. 1990, 204 pts from 51 centres were enrolled in the study. 196 were evaluable. 109 pts (55.6%) were laparotomized, 58 (29.6%) splenectomized. The accuracy for the prediction of an abdominal involvement was 72.3% in case of abnormal findings in abdominal CT/ultrasound but only 36.4% in case of enlarged lymph nodes at the pulmonary hilus without abdominal abnormalities. 91.2% of the removed spleens were proven involved. -2 out of 196 pts suffered progression under treatment, and 22 relapsed (as of 1 Jan, 1994). 6 pts died, 4 of whom succumbed to Hodgkin's disease, and 2 to intercurrent infections. 2 pts in first remission developed a secondary malignancy, namely 1 malignant histiocytoma in radiation field and 1 ANLL. Another patient developed a thyroid carcinoma following salvage therapy for a relapse. The probabilities of event-free survival (EFS) and survival after 7 years are for the total group: 85% and 97%, in group 1: 84% and 99%, in group 2: 82% and 93%, and group 3: 89% and 95%. Comparison with the precursor studies HD-82 and HD-85 reveals that the dose reduction in radiotherapy has not affected the results. Differences in EFS are exclusively correlated with changes in chemotherapy.

Adolescent↗

PubMedDate not supplied

Studies of the RB1 gene and the p53 gene in human osteosarcomas.

We analyzed 14 native osteosarcoma tissue samples for alterations of the tumor suppressor genes RB1 and p53 on the DNA level, and as far as possible, the RNA level. Southern blot analyses concerning both tumor suppressor genes were carried out in all osteosarcomas. In two cases we could demonstrate a deletion within the RB1 gene. DNA analysis of a third osteosarcoma patient revealed a rearrangement of the p53 gene. We had the opportunity of performing corresponding northern analyses in eight native osteosarcoma specimens. The RB1 gene expression was significantly decreased or completely absent in six tumor samples. In two of these tissue probes the expression of both tumor suppressor genes was missing. We determined coexistence of decreased expression of both tumor suppressor genes in one additional case. In summary, 7/14 or 6/8 cases of osteosarcomas (including only those cases which allowed both analyses) showed RB1 gene alteration. In 3/14 or 3/8 osteosarcomas we could determine p53 gene abnormalities. This may indicate that either loss of p53 function is etiologically important only for the development of some osteosarcomas, or a major part of p53 gene mutations are subtle ones and their detection requires more sophisticated techniques, which are currently under development.

Bone Neoplasms↗

PubMedDate not supplied

Early toxicity of intensified conditioning with etoposide combined with total body irradiation/cyclophosphamide or busulfan/cyclophosphamide in children undergoing autologous or allogeneic bone marrow transplantation.

In recent years, high dose chemotherapy followed by bone marrow rescue has been established as a common treatment of hematologic and solid tumor malignancies. Despite unequivocal success, relapse after transplant remains a serious problem, being the main cause of treatment failure. In an attempt to reduce relapse rates, we intensified the conditioning regimens consisting of busulfan/cyclophosphamide versus fractionated total body irradiation (f-TBI)/ cyclophosphamide by the addition of high dose etoposide. Toxicity profiles of 25 pediatric patients with hematologic malignancies undergoing intensified conditioning did not differ significantly between the two groups, except for a higher incidence of veno-occlusive disease in busulfan-treated patients (3 of 13 patients) compared with the TBI group (0 of 12 patients). We observed no transplant-related mortality in neither group. Regimen-associated morbidity was moderate and reversible in all cases. Five patients died in each treatment arm, due to relapse of the underlying disease. We conclude that both regimens are feasible in marrow transplantation of pediatric patients. Open randomized trials are needed to assess the efficacy of intensified conditioning in terms of disease-free survival.

Adolescent↗

PubMedDate not supplied

Transcription of tal-1, a putative oncogene playing an important role in childhood T-ALL, can be shown in normal peripheral blood cells by a highly sensitive RT-PCR assay.

Rearrangement of the tal-1 gene is the most frequent clonal marker in childhood T cell acute leukemia. Previously, tal-1 mRNA expression has been observed only in cells of the erythroid, mast cell, and megakaryocytic lineages and in blastic lymphoid cells of normal bone marrow, not in normal lymphocytes or monocytes of the peripheral blood (PB). In this study we addressed the question of tal-1 expression during normal hematopoietic development by performing reverse transcription-polymerase chain reaction (RT-PCR) on RNA from PB cells of 12 healthy donors. Ten of 10 unsorted samples were RT-PCR positive for tal-1 expression. Sorted T cells and monocytes from three donors showed tal-1 RT-PCR products. This is the first direct experimental evidence of tal-1 transcripts in these two normal PB cell types.

Basic Helix-Loop-Helix Proteins↗

PubMedDate not supplied

SV40 sequences in human osteosarcoma of German origin.

Simian virus 40 (SV40) is a dsDNA polyomavirus that induces osteosarcomas and mesotheliomas in hamsters and transforms many types of cells in tissue culture, including human cells. Osteosarcoma is a bone malignancy with multiple molecular lesions underlining progression from normal bone to osteosarcoma. Recent investigations have identified SV40 DNA sequences in osteosarcomas, suggesting that SV40 may contribute to tumor development. However, these studies also demonstrated that geographical differences exist between SV40 and tumor association. Our study analyzed 46 frozen German tumor specimens (42 osteosarcomas and 4 sarcomas initially suspected to be osteosarcomas) for the presence of SV40 DNA sequences by using PCR. Two different primer sets amplifying a 573 bp region of SV40 Tag gene with the complete intron sequence (SV.for 2/SV.rev) and a 172 bp region with no intron sequence (SV.5/SV.6) were used. DNA sequencing analysis verified the results. No SV40 sequences could be detected using the primer set SV.for 2/SV.rev, while 2 out of 42 osteosarcoma specimens and 1 out of 4 poorly-differentiated tumor specimens contained SV40 sequences, using the primer set SV.5/SV.6. From one of these two positive osteosarcomas, multiple tumor biopsies taken at different times during the dissection, including metastasis, tested positive for SV40. These results indicated that in Germany, only rare osteosarcomas can be linked to SV40. These results support previous findings involving geographical differences in the presence of SV40. Finally, the specific detection of SV40 sequences with multiple specimens from one of the two patients and the absence of SV40 sequences in all other samples underscores the specificity and reproducibility of this investigation and ruled out PCR contamination.

Adolescent↗

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Effects of anti-tal-1 oligodeoxynucleotides in T-ALL cell lines.

Rearrangement of the gene tal-1 leads to transcriptional dysregulation and contributes to the formation of childhood T-cell acute lymphoblastic leukemia. Therefore, we tried to interfere with the transcription of the SIL/tal-1 fusion gene, the most common form of aberrant tal-1, by treatment with antisense oligodeoxynucleotides (ODNs). The potential of two different strategies was investigated, one targeting the cell line specific SIL/tal-1 fusion region, the other using an ODN complementary to tal-1 sequence downstream of the region not affected by any of the known types of tal-1 rearrangement. With both approaches a single-dose application of 3 mumol of ODN led to a significant antiproliferative effect of a about 25-60% in two T-ALL cell lines characterized by the SIL/tal-1 fusion gene. Investigation of the tal-1 mRNA level by reverse transcription-polymerase chain reaction was in concordance with these results: In both cell lines clearly less of the tal-1-specific fragment was generated after incubation with the antisense ODN tal-1 common than in the control experiments with a mismatched ODN or no ODN at all. Neither the antiproliferation antisense effect nor the downregulation of the steady state tal-1 mRNA level was observed in control cell lines bearing wildtype tal-1.

Basic Helix-Loop-Helix Proteins↗