PubMed Health⌕ Search

Biomedical subjects

N Schmitz

Publications and source records attributed to N Schmitz.

At least 181 records · Page 10Linked to original sources
PubMed1993

Amplification of a Y-chromosomal DNA sequence by the polymerase chain reaction for documentation of residual recipient cells in small samples from bone marrow, peripheral blood and cerebrospinal fluid after bone marrow transplantation.

The long arm of the human Y-chromosome contains about 800 to 5000 copies of the tandemly repeated DNA sequence DYZ1. A major part of the repeating unit (pHY10) has been cloned and sequenced. Primers were designed to match a part of this repeat sequence for the amplification of a 154 bp fragment spanning the EcoRI restriction site of the unit. Typical dilution experiments showed that this polymerase chain reaction (PCR) method allows the detection of 5 to 10 male cells among 100,000 female cells, or in 500 microL of cerebrospinal fluid containing only one cell per microL. In addition, the quality of the DNA used for the amplification reaction is less critical, thus allowing analysis of long-term stored samples such as bone marrow smears or dried blood stains spotted onto filter paper, which might contain partially degraded DNA. We applied this technique to detect residual host cells in the clinical setting of human sex-mismatched bone marrow transplantation (BMT). Fourteen patients, receiving transplantations because of leukemias could be supervised so far. Throughout the whole period of monitoring (days +14 until +911 post BMT; median: 160 days), residual host cells were detected in all but three patients. Persistence of host cells in the early phase post-BMT was mostly transient and probably due to long-term surviving host T-lymphocytes. Reappearance of host cells several months after BMT is highly suspicious of relapse from the underlying malignancy. Due to its high sensitivity, PCR is a valuable tool in monitoring the switch from recipient to donor cell population.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1993

High-dose chemotherapy and hematopoietic stem cell rescue in patients with relapsed Hodgkin's disease.

Fifty-one consecutive patients with Hodgkin's disease (HD) have been treated with high-dose chemotherapy (HDT) and transplantation of autologous bone marrow (BM) (n = 44), autologous BM plus peripheral blood stem cells (PBSC) (n = 2), PBSC (n = 1), syngeneic (n = 1), or allogeneic BM (n = 3). All patients had received standard salvage chemotherapy prior to HDT and were classified as sensitive (n = 33) or resistant (n = 17) to this treatment; one patient was in untreated relapse prior to BMT. The preparative regimens for patients receiving autologous BM and/or PBSC consisted of cyclophosphamide, VP 16, and BCNU (CVB) (n = 44) or BCNU, etoposide, ara-C, and melphalan (BEAM) (n = 3). The patients receiving allogeneic transplants were treated with the CVB regimen (n = 2) or busulfan (16 mg/kg body wt.) and cyclophosphamide (200 mg/kg body wt.). With a median follow-up of 12 months, overall survival for 44 patients grafted with autologous BM is 61% +/- 9%, progression-free survival for patients with sensitive disease is 44% +/- 11%; no patient with resistant relapse survived beyond 1 year post transplant. Two of three patients grafted with allogeneic BM still survive 15 and 24 months after BMT with Karnofsky performance scores of 70% and 100%, respectively. The main toxicity encountered with the CVB regimen was interstitial pneumonia (IP), seen in four of 15 patients (27%) receiving > or = 600 mg/m2 of BCNU. Three of these patients have died. The results show that HDT followed by hematopoietic stem cell rescue may effectively salvage an important fraction of patients with relapsed HD who respond to standard chemotherapy. The same approach is largely unsuccessful in patients with proven refractoriness to standard chemotherapy. Whether HDT followed by BMT or PBSC support is superior to intensive chemotherapy without stem cell support can be answered only by a prospectively randomized trial.

Adolescent↗
PubMed1993

Effective mobilisation of peripheral blood progenitor cells with 'Dexa-BEAM' and G-CSF: timing of harvesting and composition of the leukapheresis product.

The mini-BEAM regimen (BCNU, etoposide, cytarabine, melphalan) and its modification 'Dexa-BEAM' are effective salvage protocols for relapsed Hodgkin's disease and non-Hodgkin's lymphoma. Since many patients with relapsed lymphoma are eligible for high-dose chemotherapy with autologous stem cell rescue, we were interested in the suitability of these second line regimens for mobilising peripheral blood progenitor cells (PBPC). The kinetics of PBPC were studied in 15 patients treated with Dexa-BEAM and granulocyte colony-stimulating factor (G-CSF). Leukocytes started to rise from < 0.5 nL-1 on day 18 (16-22) after Dexa-BEAM, and exceeded 10 nL-1 on day 20 (18-28). Peripheral blood CFU-GM peaked on day 21 (19-28) and declined slowly thereafter; the median leukocyte count was 18.7 nL-1 (12.2-60) on the day of CFU-GM-peak. The maximum number of CFU-GM circulating in peripheral blood was inversely correlated to the duration of leukopenia after Dexa-BEAM. Measurement of CD34+ cells with the monoclonal antibody 8G12-PE (HPCA-2) predicted the number of CFU-GM precisely in both peripheral blood and leukapheresis products (r = 0.90-0.95). Two to six leukapheresis procedures yielded 6.39 x 10(8) mononuclear cells kg-1 (1.82-13.49) containing 44.4 x 10(4) CFU-GM kg-1 (2.2-213.8). Immunophenotypical analysis revealed that the percentage of CD19+ B cells was very low in all collection products (less than 1%). Nine patients were autografted with PBPC (15.4-213.8 x 10(4) CFU-GM kg-1) after myeloablative chemotherapy and experienced rapid and sustained engraftment (Platelets > 50 nL-1 on day +13 [9-22]). We conclude that PBPC can be mobilised effectively by Dexa-BEAM plus G-CSF. An adequate timing of PBPC collection (when the leukocyte count has exceeded 10 nL-1) and evaluation of the progenitor content of the leukapheresis products with 8G12-PE will allow to minimise the number of leukaphereses.

Adult↗
PubMed1993

Granulocyte-colony-stimulating factor induces increased serum levels of soluble interleukin 2 receptors preceding engraftment in autologous bone marrow transplantation.

The serum levels of soluble interleukin 2 receptors (sIL-2R) were determined in 19 patients who received high-dose chemotherapy and an autologous or syngeneic bone marrow transplant (BMT) for treatment of Hodgkin's disease (n = 18) or non-Hodgkin's lymphoma (n = 1). Twelve patients received granulocyte colony-stimulating factor (G-CSF) from day 0 or day +1 after autologous BMT until the white blood cell count had been stable for 9 d above 1 x 10(9)/l, the remaining seven patients did not receive growth factors. In all G-CSF-treated patients the sIL-2R levels increased steadily in the early post-transplant course, even in the absence of infection. This increase was statistically significant 2-4 d prior to the appearance of leucocytes in the peripheral blood (median 340 pM versus median 256 pM immediately after BMT, P < 0.025) and peaked with the appearance of first peripheral blood leucocytes (median 536 pM, P < 0.001). Cessation of G-CSF administration resulted in a decline of sIL-2R levels. In contrast, five of seven patients without G-CSF treatment did not exhibit an sIL-2R increase before or at the time of engraftment. Infection was associated with a rise of sIL-2R levels. A correlation between sIL-2R levels and total leucocyte count, lymphocyte count, or CD25+ lymphocyte count was not evident. These data suggest that after autologous BMT G-CSF induces increased sIL-2R levels, which occur independent of lymphocyte activation. This may be compatible with involvement of immature bone marrow cells in G-CSF-induced sIL-2R release.

Adolescent↗
PubMed1993

Monitoring of chimerism after allogeneic bone marrow transplantation with unmanipulated marrow by use of DNA polymorphisms.

Highly polymorphic tandemly repetitive DNA sequences provide powerful genetic markers for the identification of individuals by restriction fragment length polymorphisms (RFLP) even in close relatives. Over a three-year period, 61 consecutive patients from a single institution undergoing allogeneic bone marrow transplantation (BMT) for various hematological diseases were grafted with unmanipulated marrow and followed for the development of hematopoietic chimerism. Three synthetic oligonucleotide probes homologous to the so-called minisatellite or variable number of tandem repeat (VNTR) sequences were evaluated in the clinical setting of BMT for their usefulness: (i) to document marrow engraftment or rejection; (ii) to elucidate the kinetics of mixed chimerism; and (iii) in providing a sensitive tool for early detection of relapse. In addition, in patients with CML karyotyping and analysis of bcr/abl gene rearrangement was performed. Using this panel of three oligonucleotide probes, informative markers specific for donor or recipient RFLP could be demonstrated in all cases. Engraftment could be documented in all patients surviving beyond day +14 after BMT. Mixed chimerism was detected in 14% of the patients in the early phase (day +14 to day +78) after BMT but only one patient turned out to become a long-term stable mixed chimera. These results support the hypothesis that lymphocytes of recipient origin surviving the conditioning regimen may considerably contribute to mixed chimerism early after BMT. Long-term stable mixed chimerism is a rare event after BMT with unmanipulated marrow. Simultaneous analysis of chimerism after BMT by VNTR-RFLP, karyotyping, and detection of bcr/abl rearrangement in patients with CML showed corresponding results in nine out of 12 patients. In three patients either one of the methods failed to detect residual recipient cells in the early phase after BMT. Therefore different methods for assessment of mixed chimerism seem to complement rather than to exclude each other. Eleven patients who all exhibited complete chimerism early after BMT relapsed from their underlying disease. In seven of these patients grafted for acute leukemia, analysis of DNA-RFLP had been performed shortly before clinical relapse (30-86 days) and failed to herald relapse. As the sensitivity for the detection of the minor cell population by analysis of DNA-RFLPs is approximately 1%, these data may indicate that relapse of acute leukemia after BMT is characterized by a sudden increase in the percentage of recipient blast cells not detectable even by frequent RFLP analyses.

Adolescent↗
PubMed1993

[The language of pediatric asthma patients. A study of symptom description].

BACKGROUND: Questions on asthma symptoms like "wheezing" or "whistling in the chest" must be easily understood by the general population. In preparation of a standardized German questionnaire we investigated, how children with asthma and their parents would describe symptoms during an asthma attack. METHODS: From June until December 1991, 72 children aged 13-15 years, and parents of 138 children aged 7-15 years with diagnosed asthma, where interviewed whilst they visited the outpatient department of the universities of Berlin, Leipzig, and Munich. The parents and children were asked to answer a questionnaire which included a list of adjectives and descriptions proposed to describe the child's breathing during an asthma attack. The items included descriptions which have been used on German questionnaires, others which we considered possibly useful, anc control items which we considered inappropriate. Parents and children were asked to rate on scales how much they would agree or disagree to the proposed items as possible descriptors. Descriptive and cluster analyses revealed those descriptions which received the best ratings. RESULTS: The rating was rather independent of the sex of the child, the respondent (child vs parent) and the severity of attacks, but differences between regions were observed. CONCLUSION: The verbal descriptors with the best rating will be used for the wording of a German questionnaire on asthma symptoms.

Adolescent↗
PubMed1992

Vertebrate p34cdc2 phosphorylation site mutants: effects upon cell cycle progression in the fission yeast Schizosaccharomyces pombe.

We have used the fission yeast Schizosaccharomyces pombe to analyse the effects of in vitro mutagenesis of the four known phosphorylation sites in the chicken p34(cdc2) protein, Thr 14, Tyr 15, Thr 161 and Ser 277, upon cell cycle progression. We have studied both the effect of overexpression of mutant proteins in a cdc2+ background and assayed their ability to rescue null and temperature-sensitive alleles of cdc2. Mutations of Thr 14 and Tyr 15 within the ATP binding domain of p34(cdc2) that mimic constitutive phosphorylation cause dominant negative cell cycle arrest when overexpressed. In contrast, some substitutions that simulate permanent dephosphorylation of the corresponding sites advance dephosphorylation of the corresponding sites advance mitosis. These data confirm the model that p34(cdc2) function is negatively regulated by phosphorylation of residues in the ATP binding site. Mutagenesis of the conserved residue Thr 161 functionally inactivates p34(cdc2), and our data suggest that both phosphorylation and dephosphorylation events at Thr 161 are required for progression through the cell cycle. Mutations at the fourth site of phosphorylation. Ser 277, lead to cold-sensitive cell cycle arrest, in minimal but not rich growth medium, suggesting that this site is involved in monitoring the nutritional status of the cell.

Amino Acid Sequence↗
PubMed1992

Intensive chemotherapy and bone marrow transplantation for myelodysplastic syndromes.

In myelodysplastic syndromes (MDS), complete remission rates of acute myelogenous leukemia (AML)-type chemotherapeutic regimens vary widely, ranging from 15% in patients with myelodysplasia after previous cytotoxic therapy to 61% in patients with refractory anemia with an excess of blasts in transformation without previous exposure to leukemogenic chemicals. The duration of remission is usually short, and those that exceed 24 months are unusual. Results of treatment are identical in the different types of MDS. No sufficient data on aggressive therapy are available for refractory anemia and refractory anemia with ringed sideroblasts. Prognostically favorable subgroups of patients are defined by age (below 45 or 50 years), no prior history of cytotoxic drug exposure, and absence of cytogenetic aberrations, especially of chromosomes 5 and/or 7. In contrast to AML-type chemotherapy, allogeneic bone marrow transplantation following high-dose (radio) chemotherapy offers a significantly greater chance of cure with a long-term relapse-free survival rate of 30% to 60%.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1992

[Juvenile chronic leukemia and chronic myelomonocytic leukemia. Experiences with bone marrow transplantation in childhood in 5 cases].

Chronic leukemias of early childhood (JCML/CMML) are rare malignant diseases for which effective regimens of chemotherapy have not been established. However, some of these patients may be cured by BMT. We report on 4 children with JCML and one child with CMML undergoing BMT from HLA-identical siblings and from matched unrelated donors. 3 of 5 patients are disease-free 9 to 37 months post BMT. According to our observations an effective reduction of blastic cells before BMT seems to be necessary for a sustained remission of these diseases. This reduction can be reached by intensive chemotherapy and by splenectomy before BMT. Moreover, we stress the need for total body irradiation (TBI) during BMT in order to eradicate residual malignant cells.

Blood Cell Count↗
PubMed1991

High-dose cytostatic agents in allogeneic bone marrow transplantation: comparison of the engraftment promoting potential.

We investigated the potential of various cytostatic agents for preventing graft rejection following allogeneic bone marrow transplantation. LEW rats received a lethal dose (35 mg/kg) of busulfan followed by injection of 1 x 10(8) F1(CAP x LEW) marrow cells, which are unable to induce a graft-versus-host reaction in LEW recipients. Rejection of the marrow graft was assessed by monitoring haematocrit and granulocyte counts. Due to its weak immunosuppressive activity, busulfan by itself is unable to allow engraftment of allogeneic marrow. Therefore, agents administered in addition to busulfan can be tested for their capacity to prevent marrow graft rejection. 120 mg/kg of cyclophosphamide, 20 mg/kg of ACNU and 240 mg/kg of ifosfamide completely prevented rejection of the allogeneic marrow. Maximum doses of BCNU applicable in conjunction with busulfan reduced the rejection rate to 12% (30 mg/kg) and 17% (40 mg/kg), whereas the antitumour agents thiotepa, melphalan, and carboplatin exhibited a very limited engraftment-promoting potential in this experimental setting. Thus, BCNU (carmustine), ACNU (nimustine), and ifosfamide might be suitable candidates for conditioning of allogeneic bone marrow graft recipients.

Animals↗