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Biomedical subjects

G Henze

Publications and source records attributed to G Henze.

At least 91 records · Page 5Linked to original sources
PubMed1996

Adsorptive stripping voltammetric determination of vanadium as chloranilic acid complex.

Traces of vanadium(V) can be determined up to 21 ng/l by adsorptive stripping voltammetry using 2,5-dichloro-1,4-dihydroxy-3,6-benzoquinone (chloranilic acid) as complex forming reagent. The complex is stable in a 0.1 mol/l acetate buffer (pH 4.6) solution and adsorbed at the electrode surface in a potential range between -150 mV and -400 mV. The adsorption process is solved by alternating current (ac) voltammetric measurements. The method is applied to different real samples.

Journal Article↗
PubMed1996

Voltammetric determination of Ioxynil and 2-methyl-3-nitroaniline using C(18) modified carbon paste electrodes.

The stripping voltammetric behaviour of Ioxynil and 2-methyl-3-nitroaniline has been studied by means of a C(18) modified carbon paste electrode. The analytes are preconcentrated under open-circuit conditions (Ioxynil at pH 3.9; 2-methyl-3-nitroaniline at pH 10). For the determination of Ioxynil and 2-methyl-3-nitroaniline 0.01 mol/l HCl and 1 mol/l KOH, respectively, have been used as supporting electrolyte. Under optimized conditions detection limits up to 0.1 microg/ml Ioxynil and 0.3 microg/ml 2-methyl-3-nitroaniline have been obtained. The methods have been applied to the determination of Ioxynil and 2-methyl-3-nitroaniline in drinking water.

Journal Article↗
PubMed1996

Determination of adenine, caffeine, theophylline and theobromine by HPLC with amperometric detection.

A relatively simple method for quantifying caffeine, theobromine, theophylline and adenine by HPLC with amperometric detection was developed. A C(18)-column and an isocratic elution with phosphate buffer pH 3.5/methanol (90 : 10) were employed for the chromatographic separation of the investigated compounds. The optimal detection potential was +1.4 V. The limits of detection were 0.4 ng for adenine, 1 ng for theophylline and 2.5 ng for caffeine and theobromine. The method was applied to the determination of these purine alkaloids in beverages, tea, coffee and cacao. The determination was carried out directly or after solid-phase extraction.

Journal Article↗
PubMed1996

Cerebrospinal fluid soluble L-selectin (sCD62L) in meningoencephalitis.

The leucocyte adhesion molecule L-selectin (CD62L) is rapidly cleaved off proteolytically after cell activation, generating soluble L-selectin (sCD62L) molecules. sCD62L concentrations were determined in 185 cerebrospinal fluid (CSF) samples obtained from children aged 1 month to 17 years. In 36 CSF samples of children with meningoencephalitis, sCD62L was significantly higher (median 209 fmol/ml) than in samples of children with other febrile diseases (n = 67, median 50 fmol/ml) or non-febrile disorders (n = 82, median 44 fmol/ml). There was a positive correlation between CSF protein and CSF sCD62L (rS = 0.68), suggesting that a disturbed blood-brain barrier contributes to raised sCD62L concentrations in the CSF. However, the CSF sCD62L/protein ratio of children with meningoencephalitis was significantly higher than in children with other febrile diseases or non-febrile disorders, indicating that sCD62L concentrations in children with meningoencephalitis were higher than expected from plasma leakage alone. It is concluded that both an impaired blood-brain barrier and the generation of sCD62L by infiltrating leucocytes contribute to raised CSF sCD62L concentrations in children with meningoencephalitis.

Acute Disease↗
PubMed1996

Peripheral blast counts at diagnosis of late isolated bone marrow relapse of childhood acute lymphoblastic leukemia predict response to salvage chemotherapy and outcome. Berlin-Frankfurt-Münster Relapse Study Group.

PURPOSE: In newly diagnosed childhood acute lymphoblastic leukemia (ALL), a high tumor burden indicates a poor prognosis, while no such link has been established yet after relapse. The impact of the absolute peripheral blast count (PBC) at the time of relapse on the response to salvage chemotherapy after a late isolated bone marrow (BM) relapse is the subject of this prospective analysis. PATIENTS AND METHODS: Since 1983, 260 children with a first isolated BM relapse of ALL that occurred 6 months or later after elective cessation of front-line therapy were enrolled onto four consecutive multicenter trials of the Berlin-Frankfurt-Münster (BFM) Relapse Study Group. All patients received intensive multiagent induction and consolidation chemotherapy for 6 months, followed by maintenance therapy with methotrexate (MTX) and thioguanine for 2 years. Treatment of subclinical meningeal leukemia consisted of high-dose intravenous MTX and intrathecally administered cytostatic drugs, which was augmented by cranial irradiation since 1988. RESULTS: At the time relapse was diagnosed, PBC varied considerably among patients (median, 1,060/microL; range, 0 to 106,800/microL). Achievement of a second complete remission (CR) was not significantly different in children without detectable circulating blasts at relapse (37 of 38) and those with moderate (1 to 9,999/microL) PBC (165 of 171). In contrast, only 42 of 51 children with high PBC (> or = 10,000/microL) achieved a second CR (P = .0015). At a median follow-up time of 40 months, the 10-year event-free survival (EFS) probability was significantly (P = .0001) higher in children without circulating blasts (.64) than in children with moderate PBC (.32) or high PBC (.10). There was a preponderance of boys in the group without detectable circulating blasts, while the three PBC-defined groups did not differ with respect to frontline treatment, age at initial diagnosis, age at relapse, time off therapy, or salvage treatment protocol. On sequential univariate and multivariate analysis, only duration of first remission > or = 48 months was an additional independent indicator of adverse prognosis, while preventive cranial irradiation improved outcome independently of PBC. CONCLUSION: The absence of blasts on peripheral-blood smears at the time of a first late isolated BM relapse of childhood ALL is associated with a favorable response and prognosis in chemotherapy-treated children, who should be regarded as ineligible for bone marrow transplantation (BMT) unless a second round of chemotherapy has failed to produce a response.

Adolescent↗
PubMed1996

Allogeneic BMT vs. chemotherapy in late bone marrow relapsed childhood non-T/non-B ALL: results of BFM ALL relapse studies. BFM Relapse Study Group.

In first BM relapsed non-T/non-B ALL, the outcome is not significantly different after radio-chemotherapy compared with allogeneic BMT. Therefore, radio-chemotherapy is convenient af first late BM relapse and BMT may be performed not before a second BM relapse had occurred. Only a small subgroup of children with isolated BM relapse and peripheral blast cells > or = 10,000/microliter at diagnosis of first relapse has a dismal prognosis after radio-chemotherapy and might benefit from BMT.

Adolescent↗
PubMed1996

Which children do benefit from bone marrow transplant? The EBMT Paediatric Diseases Working Party.

The development of chemotherapy in childhood ALL has been the leader of the success story of paediatric oncology. At least 2/3 of the children can be cured nowadays at the first attempt of treatment. From the remaining again 1/3 can be treated successfully for the relapse of their disease with conventional therapeutic strategies. This means, however, that there is no chance for cure with chemotherapy alone for 20 to 25% of the children. BMT has been shown for a long time to be an alternative therapy especially in those cases in which conventional chemotherapy fails. In spite of the fact that many children with ALL have been transplanted during recent years there is still no general agreement on the question which children need BMT. However a few statements can be made: The value of ABMT in ALL is probably not better than that of chemotherapy alone. In 1st CR a group of children can be defined, which might benefit from BMT. In 2nd CR the value of chemotherapy depends very much from the duration of 1st remission. Allogeneic BMT is the only chance for cure in very early relapses, superior to chemotherapy in early and late relapses and possibly equal to chemotherapy in very late relapses. The paper tries to summarise our current knowledge about the situation.

Bone Marrow Transplantation↗
PubMed1995

In vitro cellular drug resistance in children with relapsed/refractory acute lymphoblastic leukemia.

Cellular drug resistance is thought to be an important cause of the poor prognosis for children with relapsed or refractory acute lymphoblastic leukemia (ALL), but it is unknown when, to which drugs, and to what extent resistance is present. We determined in vitro resistance to 13 drugs with the MTT assay. Compared with 141 children with initial ALL, cells from 137 children with relapsed ALL were significantly more resistant to glucocorticoids, L-asparaginase, anthracyclines, and thiopurines, but not to vinca-alkaloids, cytarabine, ifosfamide, and epipodophyllotoxins. Relapsed ALL cells expressed the highest level of resistance to glucocorticoids, with a median level 357- and >24-fold more resistant to prednisolone and dexamethasone, respectively, than initial ALL cells, whereas the resistance ratios for the other drugs differed from 0.8- to 1.9-fold, intraindividual comparisons between initial and relapsed samples from 16 children with ALL showed that both de novo and acquired drug resistance were involved. Specific in vitro drug-resistance profiles were associated with high-risk relapsed ALL groups. In vitro drug resistance was also related to the clinical response to chemotherapy in relapsed/refractory childhood ALL. We conclude that drug resistance may explain the poor prognosis for children with relapsed/refractory ALL. These day may be helpful to design alternative treatment regimens for relapsed childhood ALL.

Antibiotics, Antineoplastic↗
PubMed1995

Autologous bone-marrow transplants compared with chemotherapy for children with acute lymphoblastic leukaemia in a second remission: a matched-pair analysis. The Berlin-Frankfurt-Münster Study Group.

It is unclear how best to treat children with acute lymphoblastic leukaemia (ALL) who are in a second remission. Treatment with bone-marrow transplants from HLA-identical siblings results in a statistically greater likelihood of leukaemia-free survival than does chemotherapy. Less than 25% of relapsed patients are able to benefit from this therapy due to a lack of matching donors; chemoradiotherapy or autologous BMT are considered for the rest. We compared treatment results for children who underwent autologous BMT with those who had chemotherapy. All patients were registered between 1983-94 in the multicentre trials. We selected groups of patients by matching variables associated with treatment outcome and duration of second remission. 52 matched-pairs were studied. The probability of event-free survival at 9 years was 0.32 (SD 0.07) for patients receiving chemotherapy versus 0.26 (SD 0.07) for patients who underwent autologous BMT. For two groups--children with prognostic factors indicating high risk of relapse and those with factors indicating lower risk--the outcome from transplantation did not differ significantly from that of chemotherapy: no advantage of autologous BMT over chemotherapy as post-induction treatment for children with ALL in a second remission could be detected with regard to event-free survival. Because autologous BMT has been used as the final step of treatment it is possible that its relative ineffectiveness has been due to the lack of continuation therapy after transplant. Attempts should be made to complement autologous BMT by subsequent immunotherapy, molecular biotherapy, chemotherapy, or a combination of these.

Adolescent↗
PubMed1995

[The significance of preventive CNS irradiation during antineoplastic therapy in childhood with regard to late odontogenic and mandibulofacial injuries].

The aim of the present study was to determine the adverse effects of antineoplastic chemotherapy and radiotherapy on tooth development, i.e., on dentition in general and on craniofacial growth. The patients studied consisted of 26 children with solid tumors treated with chemotherapy alone and 34 patients with acute lymphoblastic leukemia (ALL) who were treated with intensive and follow-on radiation therapy (18 and 24 Gy) to the neurocranium as a constituent of central nervous system prophylactics in treatment protocols for ALL. The treatment protocol employed in these children is known as the BFM (Berlin, Frankfurt, Münster) protocol. At the time of diagnosis the children ranged in age from 3 to 52 months. All treated patients had microdontia, enamel dysplasia, thinning and tapering of apical roots portions, and marked shortening of the roots. These defects were more pronounced in children treated for ALL, but it was not possible to establish statistically relevant evidence on the influence of adjuvant radiotherapy in this group. This indicates that there is a catch up in craniofacial growth 9 years after therapy and that the most serious long-term adverse effects are on dentition.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Non-Hodgkin's lymphomas of childhood and adolescence: results of a treatment stratified for biologic subtypes and stage--a report of the Berlin-Frankfurt-Münster Group.

PURPOSE: To prove the efficacy of a treatment stratified according to histology for children with non-Hodgkin's lymphoma (NHL), including acute B-cell leukemia (B-ALL). PATIENTS AND METHODS: From October 1986 to March 1990, 302 assessable patients, 0.6 to 17.8 years of age, with newly diagnosed NHL were enrolled onto study ALL/NHL-BFM 86. Fifty percent of patients had Burkitt-type lymphomas, including B-ALL; 24% had lymphoblastic lymphoma; 18% had diffuse large-cell lymphoma; and 8% had an NHL not further classified. Therapy group B included Burkitt's-type lymphomas, B-ALL, and most large-cell lymphomas including Ki-1 anaplastic large-cell lymphoma. Patients with stage I and II disease resected received three, while all others received six, 5-day therapy courses (dexamethasone, methotrexate [MTX] 0.5 g/m2 [5 g/m2 for stage IV and B-ALL], and intrathecal [IT] therapy in each course, plus ifosfamide, cytarabine, and etoposide alternating with cyclophosphamide and doxorubicin). Therapy for group non-B patients (lymphoblastic lymphoma and pleomorphic T-cell lymphoma [PTCL]) consisted of a Berlin-Frankfurt-Münster (BFM) acute lymphoblastic leukemia protocol, including cranial irradiation for advanced stage. Local therapy was restricted to patients with incomplete tumor regression. RESULTS: The probabilities of event-free survival (pEFS) at 7 years were 80% +/- 2% for the whole group, 81% +/- 3% for group B (n = 225), and 78% +/- 5% for group non-B (n = 77) with a follow-up duration of 3.6 to 7 years (median 5 years). Treatment results were comparable between NHL subtypes, except for PTCL, in which three of four patients suffered from relapse. Local disease manifestations were the most frequent site of failure. CONCLUSION: This therapy strategy provided patients of all NHL subtypes with an equally high chance to survive event-free, except patients with PTCL. With reduced systemic failure, local tumor control may become more important.

Adolescent↗
PubMed1995

Isolated extramedullary relapse in children with acute lymphoblastic leukemia: a comparison between treatment results of chemotherapy and bone marrow transplantation. BFM Relapse Study Group.

The purpose of this study was to determine the therapeutic efficacy of different treatment strategies, namely chemotherapy, allogeneic and autologous bone marrow transplantation (BMT), for extramedullary relapse of acute lymphoblastic leukemia (ALL) in children in second or subsequent remission. Between 1983 and 1993, 165 patients up to 19 years of age with extramedullary relapse of ALL were registered in the multicenter ALL-REZ BFM trials. One hundred and thirty four children received chemotherapy only; 17 children were grafted from HLA-identical sibling donors 152 days (46-392 days) after diagnosis of relapse, and 14 children underwent autologous BMT after a median time of 137 (range 23-300) days. Event-free survival (EFS) at 5 years was 0.47 +/- 0.05 for patients receiving chemotherapy: 0.76 +/- 0.07 for late, 0.33 +/- 0.08 for early and 0.33 +/- 0.07 for very early relapsed patients. Sixty five patients are in complete remission (CR), 61 patients relapsed, 5 died from therapy related complications, 2 patients in CR were lost to follow-up and one patient developed a second malignancy. For patients who had undergone BMT, EFS at 5 years was 0.36 +/- 0.10 without significant difference between autologous BMT (8 of 14 in CR, 6 relapsed) and allogeneic BMT (6 of 17 in CR, 4 died of acute toxicity, and 7 relapsed).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

High-performance liquid chromatographic determination of methotrexate, 7-hydroxymethotrexate, 5-methyltetrahydrofolic acid and folinic acid in serum and cerebrospinal fluid.

A method for the simultaneous determination of the antifolates methotrexate and 7-hydroxymethotrexate as well as the folates 5-methyltetrahydrofolic acid and folinic acid (5-formyltetrahydrofolic acid) in serum and cerebrospinal fluid (CSF) is described. High-performance liquid chromatography with gradient elution and dual detection (ultraviolet absorption and fluorescence) was used to separate and quantitate the analytes. Serum samples containing high levels of the substances of interest and CSF samples were injected directly onto the HPLC column. For determination of low concentrations, serum samples were subjected to a solid-phase extraction method for clean-up and concentration purposes. The determination limits were 10 ng/ml for both antifolates, 100 ng/ml for folinic acid, and 0.1 ng/ml for the physiologically occurring methylated folate which is about 1/100 the serum concentration in healthy children. The suitability of the method for pharmacokinetic monitoring of high-dose methotrexate therapy combined with leucovorin rescue administered to children with acute lymphoblastic leukemia was demonstrated. Minimum values of the serum folate during treatment ranged from 0.2 to 3.1 ng/ml. Even those very low concentrations could be reliably measured.

Calibration↗
PubMed1994

Chemotherapy in 998 unselected childhood acute lymphoblastic leukemia patients. Results and conclusions of the multicenter trial ALL-BFM 86.

In trial ALL-BFM 86, the largest multicenter trial of the Berlin-Frankfurt-Münster (BFM) study group for childhood acute lymphoblastic leukemia (ALL), treatment response was used as an overriding stratification factor for the first time. In the previous trial ALL-BFM 83, the in vivo response to initial prednisone treatment was evaluated prospectively. A blast cell count of > or = 1,000/microL peripheral blood after a 7-day exposure to prednisone and one intrathecal dose of methotrexate (MTX) identified 10% of the patients as having a significantly worse prognosis. In trial ALL-BFM 86 patients with > or = 1,000/microL blood blasts on day 8 were included in an experimental branch EG. Patients with < 1,000/microL blood blasts on day 8 were stratified by their leukemic cell burden into two branches, Standard Risk Group (SRG) and Risk Group (RG). SRG patients received an eight-drug induction followed by consolidation protocol M (6-mercaptopurine, high-dose [HD] MTX 4 x 5 g/m2) and maintenance. RG patients were treated with an additional eight-drug reinduction element. For EG patients protocol M was replaced by protocol E (prednisone, HD-MTX, HD-cytarabine, ifosfamide, mitoxantrone). All patients received intrathecal MTX therapy; only those of branches RG and EG received cranial irradiation. In branch RG, patients were randomized to receive or not to receive late intensification (prednisone, vindesine, teniposide, ifosfamide, HD-cytarabine) in the 13th month. During the trial reinduction therapy was introduced in branch SRG, because in the follow-up of trial ALL-BFM 83 the randomized low-risk patients receiving reinduction did significantly better. Nine hundred ninety-eight evaluable patients were enrolled, 28.6% in SRG, 61.1% in RG, 10.3% in EG. At a median follow-up of 5.0 (range 3.4 to 6.9) years, the estimated 6-year event-free survival was 72% +/- 2% for the study population, 58% +/- 5% in branch SRG for the first 110 patients without reinduction therapy, 87% +/- 3% for the next 175 patients with reinduction therapy, 75% +/- 2% in branch RG, and 48% +/- 5% in branch EG. Late intensification did not significantly affect treatment outcome of RG patients; however, only 23% of the eligible patients were randomized. Prednisone poor response remained a negative prognostic parameter despite intensified therapy. The results confirmed the benefit of intensive reinduction therapy even for low-risk patients. The strategy of induction, consolidation, and intensive reinduction may offer roughly 75% of unselected childhood ALL patients the chance for an event-free survival.

Adolescent↗
PubMed1994

Importance of effective central nervous system therapy in isolated bone marrow relapse of childhood acute lymphoblastic leukemia. BFM (Berlin-Frankfurt-Münster) Relapse Study Group.

Presymptomatic central nervous system (CNS) treatment in children with a late isolated first bone marrow (BM) relapse of acute lymphoblastic leukemia (ALL) was based on intermediate-dose systemic and intrathecal (IT) methotrexate (MTX) in the multicenter trial, ALL-REZ BFM 85. Because this was associated with an excess of overt second CNS relapses, cranial radiotherapy (cRT) plus prolonged triple IT therapy with MTX, cytarabine, and prednisone was instituted during the course of the subsequent trial, ALL-REZ BFM 87. Results of children with or without cRT, but otherwise identical chemotherapy, are presented here. Between April 1985 and March 1990, 93 children with their first late isolated BM relapse of ALL were entered on protocols ALL-REZ BFM 85M and ALL-REZ BFM 87. An intensive 6-month phase of multiagent chemotherapy that included 8 courses of systemic MTX (1 g/m2) plus IT MTX was followed by 2 years of conventional maintenance therapy with daily 6-thioguanine and biweekly MTX. Children with bone marrow transplantation excluded, 73 were in complete remission at the end of intensive polychemotherapy, 40 of whom received fractionated cRT plus triple IT therapy during the following 6 months; 11 did not receive cRT but prolonged triple IT; 22 received neither cRT nor prolonged triple IT. Except for a higher percentage of children who had received cRT in front-line protocols (29 of 33 v 20 of 40), the patient groups without or with salvage cRT were comparable. Of 33 children without salvage cRT, 26 relapsed, compared with 21 of 40 who had received cRT (P < .05). The difference was solely attributable to second relapses with CNS involvement (10 of 33 v 1 of 40; P < .01). Estimated 6-year event-free survival rates were .18 for children without cRT and .46 for children with cRT (P < .01). In patients without cRT, no impact of prolonged IT therapy could be shown. The data suggest that second CNS prophylaxis with cRT and prolonged triple IT therapy in children with late isolated BM relapse of ALL is effective in preventing CNS relapses, in reducing the overall relapse rate, and in increasing the overall survival rate.

Adolescent↗