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J Rischewski

Publications and source records attributed to J Rischewski.

7 recordsLinked to original sources
PubMed2002

Long-term follow-up of allogeneic stem cell transplantation in patients with severe aplastic anemia after conditioning with cyclophosphamide plus antithymocyte globulin.

We investigated the efficacy of an antithymocyte globulin/cyclophosphamide preparative regimen prior to allogeneic stem cell transplantation from HLA-identical siblings in patients with severe aplastic anemia. Since 1990, 21 patients, 6 males and 15 females, with a median age of 25 years (range: 7-43) have been enrolled in the protocol consisting of 200 mg/kg cyclophosphamide and 90-120 mg/kg antithymocyte globulin (ATG, rabbit, Fresenius, Bad Homburg, Germany). For further graft-versus-host disease (GVHD) prophylaxis all patients received cyclosporin A and a short course of methotrexate (MTX). Only one patient had a primary graft failure (5%). All other patients engrafted with a leukocyte count >1.0 x 10(9)/l and a platelet count >20 x 10(9)/l after a median of 19 (range: 11-28) and 26 days (range: 13-67), respectively. No late graft failure or relapse was observed. Two patients experienced mild acute GVHD grade I (10%), and one patient developed grade II GVHD (5%). No severe grade III/IV GVHD was observed; 17% of the patients developed limited chronic GVHD. The treatment-related mortality was 14% and mainly due to fungal infection. After a median follow-up of 70 months (range: 2-139), the estimated overall and event-free survival at 10 years for all patients is 86% (95% confidence interval: 70-100%). We conclude that ATG plus cyclophosphamide is an effective conditioning regimen in patients with aplastic anemia undergoing stem cell transplantation with a low treatment-related mortality, resulting in an excellent outcome.

Adolescent↗
PubMed2002

In vivo T cell depletion with pretransplant anti-thymocyte globulin reduces graft-versus-host disease without increasing relapse in good risk myeloid leukemia patients after stem cell transplantation from matched related donors.

One-hundred and two patients with good risk myeloid leukemia (CML first chronic phase or AML first CR) were transplanted from HLA-related donors after conditioning with (n = 45) or without anti-thymocyte globulin (ATG) (n = 57). One graft failure was observed in the non-ATG and none in the ATG group. The median time to leukocyte engraftment (> 1 x 10(9)/l) was 16 (range 12-33) in the ATG group and 17 days (range 11-29) in the non-ATG group (NS) and for platelet engraftment (> 20 x 10(9)/l) 24 and 19 days (P = 0.002), respectively. Acute GVHD grade II-IV was observed in 47% of the non-ATG and in 20% of the ATG group (P = 0.004). Grade III/IV GVHD occurred in 7% of the ATG and in 32% of the non-ATG group (P = 0.002). Chronic GVHD was seen in 36% and 67% (P = 0.005), respectively. After a median follow-up of 48 months (range 2-128), the 5-year estimated OS is 66% (95% KI: 51-81%) for the ATG group and 59% (95% KI: 46-72%) for the non-ATG group (NS). The 5-year estimated DFS is 64% (95% KI: 50-78%) for ATG and 55% (95% KI: 43-67%) for the non-ATG regimen (NS). The 5-year probability of relapse was 5% in the ATG and 15% in the non-ATG group (NS). ATG as part of the conditioning regimen leads to a significant reduction in GVHD without increase of relapse in patients with myeloid leukemia after stem cell transplantation from HLA-related donors.

Adolescent↗
PubMed2001

Screening strategies for a highly polymorphic gene: DHPLC analysis of the Fanconi anemia group A gene.

INTRODUCTION: Patients with Fanconi anemia (Fanc) are at risk of developing leukemia. Mutations of the group A gene (FancA) are most common. A multitude of polymorphisms and mutations within the 43 exons of the gene are described. To examine the role of heterozygosity as a risk factor for malignancies, a partially automatized screening method to identify aberrations was needed. We report on our experience with DHPLC (WAVE (Transgenomic)). METHODS: PCR amplification of all 43 exons from one individual was performed on one microtiter plate on a gradient thermocycler. DHPLC analysis conditions were established via melting curves, prediction software, and test runs with aberrant samples. PCR products were analyzed twice: native, and after adding a WT-PCR product. Retention patterns were compared with previously identified polymorphic PCR products or mutants. RESULTS AND DISCUSSION: We have defined the mutation screening conditions for all 43 exons of FancA using DHPLC. So far, 40 different sequence variations have been detected in more than 100 individuals. The native analysis identifies heterozygous individuals, and the second run detects homozygous aberrations. Retention patterns are specific for the underlying sequence aberration, thus reducing sequencing demand and costs. DHPLC is a valuable tool for reproducible recognition of known sequence aberrations and screening for unknown mutations in the highly polymorphic FancA gene.

Base Sequence↗
PubMed2001

Denaturing HPLC for identification of clonal T-cell receptor gamma rearrangements in newly diagnosed acute lymphoblastic leukemia.

BACKGROUND: Denaturing HPLC (DHPLC) can be used to screen DNA for known and unknown mutations. We describe a novel, HPLC-based method for discrimination among polyclonal, oligoclonal, and/or clonal T-cell receptor gamma (TCR-gamma) rearrangements in samples from children with newly diagnosed acute lymphoblastic leukemia. METHODS: TCR rearrangements were PCR amplified from initial leukemic samples and, after heteroduplex-induction, the clonality status of each product was evaluated. To attain this, we used DHPLC on a high-resolution micropellicular matrix. Running conditions were established by melting-curve analysis of known clonal and polyclonal products and melting-point prediction software. Elution profiles were studied at 50 degrees C (native) and, to achieve optimal separation, at different column temperatures between 56 and 64 degrees C. RESULTS: For VgammaI-Jgamma1.3/2.3 rearrangements, an analysis temperature of 60 degrees C with a linear triethylammoniumacetate-acetonitrile gradient separated clonal bands from the polyclonal background amplification. Less than 15% clonal PCR product was detectable in mixtures of initial leukemic cell DNA and polyclonal DNA. Biallelic rearrangements produced two sharp peaks. Clonality of PCR products from 100 initial leukemic samples was completely identified in all investigated cases. CONCLUSIONS: Heteroduplex analysis with standardized DHPLC conditions simplifies the detection of unknown clonal or polyclonal TCR rearrangements in newly diagnosed leukemias. Clonal targets for detection of minimal residual disease are available after a short, automated analysis of PCR amplified rearrangements.

Base Sequence↗
PubMed2000

Molecular analysis in glycogen storage disease 1 non-A: DHPLC detection of the highly prevalent exon 8 mutations of the G6PT1 gene in German patients.

We investigated the molecular basis of glycogen storage disease type 1 non-A (GSD1 non-A) in 21patients. In addition to 8 novel mutations within the G6PT1 gene (c.250T>A, c.580G>A, c.627C>T, c.653-4delAG, c. 844C>A, c.1071A>C, c.1268G>A, c.1348G>A), we found a remarkably high prevalence of exon 8 mutations in German patients. The c.1211-2delCT mutation and the c.1184G>T mutation accounted for 32% and 29% of mutant chromosomes, respectively, supporting the hypothesis of a Middle European origin of these two mutations. Together with less common mutations, 79% of German GSD1 non-A patients were either homozygous or heterozygous for an exon 8 mutation. In addition to direct sequencing, these exon8 mutations could be detected by mutation-specific methods such as the detection of heteroduplex formation on polyacrylamide gel electrophoresis or by the amplification of DNA segments by allele-specific oligonucleotides. Furthermore, the use of denaturating high performance liquid chromatography (DHPLC) allowed a 100% detection and discrimination of all exon 8 mutations. In conclusion from these results, we recommend the use of either conventional or DHPLC screening as the initial non-invasive and efficient diagnostic procedure in patients with GSD1 non-A from populations with a similar distribution of mutations. Hum Mutat 16:177, 2000.

Antiporters↗
PubMed1993

Delayed pattern discrimination in patients with unilateral temporal lobe damage.

Behavioral and neurophysiological studies in macaque monkeys suggest a role of the inferior temporal cortex in pattern discrimination and visual memory. To determine whether this cortical area is also involved in human short-term visual memory, we measured spatial frequency discrimination thresholds for sequentially presented stimuli in 17 patients with unilateral, postoperative focal damage to the temporal cortex (11 left, 6 right hemisphere). These results are compared to those of 17 age-matched control subjects. Contrast detection thresholds and difference thresholds for spatial frequency were determined for spatially truncated sine wave gratings presented in the left and right visual fields. Detection thresholds were measured for sine wave gratings in a spatial two-alternative forced-choice procedure for three spatial frequencies [2.5, 5, and 10 cycles (c)/degree] for each hemifield. Discrimination thresholds were determined for two gratings sequentially presented either 4 degrees to the left or right of fixation. Grating contrast was five times the value of detection threshold and reference frequency was 5 c/degree. Within each trial, the gratings were separated in time by 1, 3, and 10 sec interstimulus intervals (ISIs), and subjects signaled which grating had the higher spatial frequency. The results indicate that (1) contrast detection thresholds overall did not differ between patient and control groups; (2) spatial frequency discrimination thresholds were, however, significantly elevated in patients and this elevation was significantly more pronounced in the visual field contralateral to the damaged hemisphere; and (3) patients with inferotemporal damage exhibited higher discrimination thresholds for the longest ISI, whereas patients with medial/superior temporal lobe damage did not show this effect. The results suggest that visual areas in human temporal cortex are involved in the higher visual processes underlying delayed pattern discrimination.

Adult↗