Search PubMed⌕ Search

Biomedical subjects

W Hiddemann

Publications and source records attributed to W Hiddemann.

At least 109 records · Page 6Linked to original sources
PubMed2001

Fludarabine plus cyclophosphamide is an efficient treatment for advanced chronic lymphocytic leukaemia (CLL): results of a phase II study of the German CLL Study Group.

The efficacy and toxicity of a combination of fludarabine and cyclophosphamide (FC) was evaluated in patients with B-cell chronic lymphocytic leukaemia (CLL). Between April 1997 and July 1998, 36 patients with CLL (median age 59 years) received a regimen that consisted of fludarabine 30 mg/m(2) in a 30-min IV infusion, d 1-3, and cyclophosphamide 250 mg/m(2) in a 30-min IV infusion on d 1-3. Cycles were repeated every 28 d. Twenty-one patients had received between one and three different treatment regimens prior to the study, while 15 patients had received no prior therapy. The median Eastern Cooperative Oncology Group performance score was 1. One patient was at Binet stage A, 18 were stage B and 17 patients were stage C. Objective responses, assessed according to the revised guidelines of the National Cancer Institute-sponsored Working Group, were recorded in 29 out of 32 assessable patients (90.6%). Twenty-four partial remissions and five complete remissions were observed. Two patients showed no change and one patient showed disease progression. At February 2000, three of the responders had relapsed. Severe neutropenia, anaemia and thrombocytopenia (Common Toxicity Criteria grade 3 and 4) were observed in 25, six and six patients (69.4%, 16.7% and 16.7%) respectively. Other side-effects were uncommon. No treatment-related deaths and no grade 3 or 4 infections occurred. We conclude that the combination of fludarabine and cyclophosphamide showed significant activity in patients with CLL. Myelosuppression was the major side-effect. These results warrant further study on the FC combination in randomized trials.

Adult↗
PubMed2001

Acute myeloid leukaemia (AML): treatment of the older patient.

Undertreatment of the older patients with acute myeloid leukaemia (AML) can explain, in part, their inferior outcome when compared with that of younger patients. Corresponding to the benefit to patients under the age of 60 from high-dose Ara-C there are also dose effects in those over 60 years old, in particular for daunorubicin in the induction treatment, and for the quantity in terms of duration of postremission treatment. The use of these effects can partly overcome the mostly unfavourable disease biology seen in older age AML patients, which is expressed by the absence of favourable and the over-representation of adverse chromosomal abnormalities as well as by the expression of drug resistance. We recommend an adequate dosage of 60 mg/m(2)daunorubicin for 3 days in combination with standard dose Ara-C and 6-thioguanine given for induction and consolidation, followed by a prolonged monthly maintenance chemotherapy for a duration of at least 1 year. Further improvements in supportive care may help in delivering additional anti-leukaemic cytotoxicity. As a novel approach, non-myeloablative preparative regimens may open up the field of allogeneic transplantation for older patients with AML. Given that the actual median age in this disease is more than 60 years the management of older age AML remains as the major challenge.

Acute Disease↗
PubMed2001

An orthotopic model of ductal adenocarcinoma of the pancreas in severe combined immunodeficient mice representing all steps of the metastatic cascade.

INTRODUCTION: Clinically relevant animal models are needed to evaluate new therapeutic strategies against pancreatic adenocarcinoma, which is almost incurable by established treatment. AIMS: To establish and characterize a metastatic orthotopic transplant model for pancreatic ductal adenocarcinoma in severe combined immunodeficient (SCID) mice. METHODOLOGY: Human pancreatic ductal carcinoma cells, PancTu 1, were implanted either subcutaneously or orthotopically into the pancreas. RESULTS: After 4 weeks, orthotopic transplantation resulted in an extensive local tumor growth of an undifferentiated ductal adenocarcinoma with slight to moderate desmoplastic reaction. The tumor growth and spread resembled the situation in humans, including invasion into adjacent organs causing biliary and stomach obstruction. In addition, tumor metastases to regional lymph nodes of the pancreas, lung, liver, mesentery, and diaphragm, and attached to the kidneys, spleen, and reproductive organs were observed. In contrast, no invasion or metastases could be demonstrated by subcutaneous implanted PancTu I cells. Using immunohistochemical analysis, even single human tumor cells could be detected in blood vessels and metastatic organs, providing evidence that the orthotopic transplant model appropriately reflects the entire process of the metastatic cascade. CONCLUSION: This cancer model in SCID mice appears to be a powerful tool to investigate the identity of metastasis-associated genes and to evaluate preclinically the potency of novel antimetastatic agents in ductal adenocarcinoma of the pancreas.

Animals↗
PubMed2001

A 14-mer Hsp70 peptide stimulates natural killer (NK) cell activity.

Compared with normal cells, tumor cell lines exhibit an unusual plasma membrane localization of heat shock protein 70 (Hsp70). This tumor-selective Hsp70 membrane expression has been found to correlate with an increased sensitivity to lysis mediated by human natural killer (NK) cells that transiently adhere to plastic following cytokine stimulation. A human Hsp70-specific monoclonal antibody (mAb) detects membrane-bound Hsp70 on viable tumor cells and blocks the immune response of NK cells against Hsp70-expressing tumor cells. By peptide scanning (pep-scan) analysis, the epitope of this mAb was mapped as the C-terminal-localized 8-mer NLLGRFEL (NLL, amino acids [aa] 454-461). Most interestingly, similar to full-length Hsp70 protein, the N-terminal-extended 14-mer peptide TKDNNLLGRFELSG (TKD, aa 450-463) was able to stimulate the cytolytic and proliferative activity of NK cells at concentrations equivalent to full-length Hsp70 protein. Blocking studies revealed that an excess of the 14-mer peptide TKDNNLLGRFELSG inhibits the cytolytic activity of NK cells similar to that of Hsp70 protein. In comparison, other TKD-related peptides, including the 8-mer antibody epitope NLLGRFEL (aa 454-461), the 12-mer TKDNNLLGRFEL (aa 450-461), the 13-mer C-terminal-extended peptide NLLGRFELSGIPP (aa 454-466), the 14-mer TKD-equivalent sequences of Hsp70hom TKDNNLLGRFELTG (aa 450-463), Hsc70 TKDNNLLGKFELTG (aa 450-463), and DnaK AADNKSLGQFNLDG (aa 447-460) failed to activate NK activity.

Amino Acid Sequence↗
PubMed2001

Constitutive activation of STAT transcription factors in acute myelogenous leukemia.

Hematopoietic growth factors (HGF) are essential for proliferation and differentiation of hematopoietic precursors and activate a distinct set of JAK-STAT (Janus kinases-signal transducers and activators of transcription) proteins. Previous results from our group have shown a strong expression of JAK-STAT proteins in primary acute myelogenous leukemia (AML) blasts and AML cell lines. Here, we asked whether a constitutive activation of the JAK-STAT pathway might be involved in the pathogenesis of AML. We could demonstrate a constitutive activation of STAT1, 3 and 5 by immunoprecipitation of the tyrosine phosphorylated proteins in different human AML cell lines. Three patterns of STAT activation were found: (I) activation of only STAT1, (II) activation of STAT1 in combination with STAT3, and (III) activation of STAT1, 3 and 5. Furthermore, STAT1 and 3 formed stable heterodimers only in cell lines with constitutive STAT3 activation. In all cell lines analyzed, tyrosine phosphorylation of the four known Janus kinases could not be detected, although JAK1 was stably associated with STAT3. To further analyze whether a constitutive activation of tyrosine kinases might contribute to the autonomous growth of AML blasts, inhibitor studies were performed. The tyrphostin AG490, an inhibitor of the JAK-STAT pathway, but not A1, an inactive tyrphostin induced a time- and dose-dependent growth arrest without overt morphological signs of differentiation in AML cell lines. Our results show that STAT transcription factors are constitutively activated in human AML cell lines and might contribute to the autonomous proliferation of AML blasts. Inhibition of this pathway might be of interest for the establishment of more specific antileukemic strategies.

Acute Disease↗
PubMed2000

Adoptive transfer of human natural killer cells in mice with severe combined immunodeficiency inhibits growth of Hsp70-expressing tumors.

In vitro, tumor-selective Hsp70 plasma membrane localization correlates with increased sensitivity to lysis mediated by a subpopulation of human natural killer (NK) cells that adhere to plastic following cytokine stimulation. In the present study, we analyzed the capacity of adoptively transferred human NK cells in SCID/beige mice for local tumor control and prevention of metastatic dissemination of Hsp70-expressing CX(+) and non-expressing CX(-) tumors following orthotopic (o.t.) injection. Both tumor sublines were derived by cell sorting of the original cell line, CX2, and thus exhibit an identical MHC and adhesion molecule expression pattern but differ with respect to Hsp70 plasma membrane expression. Viability of adherent, human NK cells in SCID/beige mice up to 18 days and the capacity to migrate have been demonstrated. Growth of Hsp70-expressing and non-expressing CX(+) and CX(-) tumor cells was completely suppressed when 10 x 10(6) NK cells were injected into the i.p. cavity on day 4 after inoculation of 2.5 x 10(6) tumor cells. Although a single injection of 5 or 2.5 x 10(6) NK cells was not sufficient to suppress tumor growth completely in all mice, the reduction in size of CX(+) tumors was significantly greater than that of CX(-) tumors. To mimic the clinical situation, ex vivo stimulated NK cells were injected i.v. on day 4 after o.t. injection of tumor cells. Under these conditions, growth of Hsp70-expressing primary tumors and metastases was suppressed. If CX(-) tumor cells were injected, 3 of 9 mice developed Hsp70-negative primary tumors. However, none of these mice developed distant metastases. In summary, our data indicate that Hsp70 acts as a recognition structure for adherent NK cells in a SCID/beige mouse model.

Animals↗
PubMed2000

[Unclear lactate acidosis in a patient with heart failure under long-term diuretic therapy].

HISTORY AND CLINICAL PRESENTATION: A severely ill 84-year old patient, known to suffer from a chronic congestive heart failure, was admitted to the emergency room because of increasing dyspnea. His blood pressure was stable (125/80), his heart rate normal (66/min), the respiratory rate, however, was elevated at 35/min and he exhibited substantial peripheral edema. There were no signs indicating an infectious process. EXAMINATIONS: Blood gas analysis yielded a marked, respiratorically compensated metabolic acidosis with a base excess of -8.6. The chest roentgenography showed a markedly dilated heart without pulmonary-vascular congestion or infiltrates. The serum lactate was substantially increased at 11.4 mmol/l (0.6-2.44). TREATMENT AND COURSE: A cardiovascular beriberi syndrome was suspected and 100 mg of thiamine administered i.v. Within hours the clinical picture improved significantly. Two hours after administration of thiamine serum lactate concentration was 5.7 mmol/l, about 12 hours later the patient suffered no longer from dyspnea and the lactate was at a normal level. CONCLUSION: Thiamine deficiency as a cause for an elevated serum lactate or lactate acidosis with or without cardiovascular failure may not be overlooked. Without adequate treatment it may end lethally, although it can be treated easily, effectively and without side effects. The potential frequency of thiamine deficiency among the normal population even in our society may be under-estimated due to the particular properties of this vitamin.

Acidosis, Lactic↗
PubMed2000

Chromosomal organization and localization of the human histone deacetylase 5 gene (HDAC5).

Histone deacetylases (HDACs) are important participants in the remodeling of chromatin structure and in the regulation of eukaryotic proliferation and differentiation. We have isolated and characterized the human HDAC5 genomic sequence, which spans a region of 39,138 bp and which has one single chromosomal locus. Determination of the exon-intron splice junctions established that HDAC5 is encoded by 26 exons ranging in size from 22 bp (exon 1) to 285 bp (exon 12). Characterization of the 5' flanking genomic region revealed that the human HDAC5 promoter lacks both the canonical TATA and CCAAT boxes. The human HDAC5 mRNA encodes a 1122 aa protein with a predictive molecular mass of 121.9 kDa and an isoelectric point of 5.84. Fluorescence in situ hybridization analysis localized the human HDAC5 gene to chromosome 17q21, a region which is characterized by frequent gains and losses of chromosomal material in several types of cancer.

Amino Acid Sequence↗
PubMed2000

Improved outcome in childhood acute lymphoblastic leukemia despite reduced use of anthracyclines and cranial radiotherapy: results of trial ALL-BFM 90. German-Austrian-Swiss ALL-BFM Study Group.

Trial ALL-BFM 90 was designed to improve outcome in patients with childhood acute lymphoblastic leukemia (ALL) by using a reduced treatment regimen. Patients were stratified into a standard-risk group (SRG), a medium-risk group (MRG), both defined by adequate early treatment response; and a high-risk group (HRG), defined by inadequate response to the cytoreductive prednisone prephase, induction failure, or Philadelphia-chromosome-positive ALL. Four treatment modifications were evaluated: dose intensification in induction by a more rapid drug sequence; administration of L-asparaginase during consolidation therapy in the MRG (randomized); enforced consolidation by rotational elements in the HRG; and reduction in the dose of anthracyclines and use of only 12-Gy preventive cranial radiotherapy in the MRG and HRG, with the aim of avoiding toxicity. Among all 2178 patients (</= 18 years of age), the 6-year event-free survival (EFS) rate (+/- SE) was 78% +/- 1%, with a median observation time of 4.8 years. EFS was 85% +/- 2% in the SRG (n = 636) and 82% +/- 1% in the MRG (n = 1299). L-asparaginase did not improve outcome in the MRG: the event-free interval was 83% +/- 2% with L-asparaginase (n = 528) and 81% +/- 2% without it (n = 557). Because there were more systemic relapses in the HRG (n = 243), EFS was 34% +/- 3%, an outcome inferior to that in the HRG in a previous trial, ALL-BFM 86, in which EFS was 47% +/- 5% (P =.04). The rates of isolated central nervous system relapse in the MRG and HRG were 0.8% and 1.6%, respectively; thus, the 12-Gy preventive cranial radiotherapy regimen apparently provided sufficient central nervous system prophylaxis. The overall improvement over the results in ALL-BFM 86 (6-year EFS, 72%; P =. 001) was based on fewer recurrences among patients in the MRG with B-cell-precursor ALL, indicating an advantage of more condensed induction therapy. In multivariate analysis, inadequate in vivo response emerged as the strongest adverse prognostic variable.

Adolescent↗
PubMed2000

Operative and conservative management of primary gastric lymphoma: interim results of a German multicenter study.

PURPOSE/OBJECTIVE: Biology and appropriate management of gastrointestinal (GI lymphomas are matters of an ongoing controversial debate. To evaluate histological features, sites of involvement and management of primary GI-lymphomas, a prospective multicentric study was initiated in 10/1992. Aim of study was the further standardization of operative and conservative treatment modalities. MATERIALS AND METHODS: Study started 10/1992 and was closed 11/1996. A total of 381 evaluable patients had been accrued then. Standardized diagnostic workup included endoscopic and radiological evaluation of the complete GI-tract as well as a central histological review. Diagnosis was established after Lewin, stage classification was made after Musshoff, and histological classification was made after Isaacson. Treatment decision concerning operative or conservative management was due to the initially acting physician. Patients with resection of low grade lymphoma received total abdominal irradiation 30 Gy + 10 Gy boost to incompletely resected areas. After resection of high grade lymphoma CHOP chemotherapy (4 cycles for stage IE, 6 cycles for higher stages) after McKelvy was followed by total abdominal irradiation 30 Gy for stage IE respectively involved field irradiation 30 Gy for higher stages with 10 Gy boost to incompletely resected areas. Primary conservative- treatment consisted of six cycles COP chemotherapy after Bagley for low grade lymphomas stage > IE and total abdominal irradiation 30 Gy + 10 Gy boost to involved areas for all stages. Patients with high grade lymphomas received 4 x CHOP followed by total abdominal irradiation 30 Gy + 10 Gy boost to involved areas or 6 x CHOP plus involved field radiation therapy with 40 Gy. 257 patients are considered for analysis due to exclusion criteria of the study, 190 of them were suffered from gastric lymphoma. Their median observation time is 29 months, maximum observation time is 68 months. RESULTS: Sites of involvement were stomach in 73.4%, small bowel 9.6%, ileocoecal region 6.9%, and other sites 3.2% More than one GI site was involved in 6.9%. Gastric lymphomas achieved a survival probability of 89% after 3 years. Though surgical and conservative treatment was not randomized, outcome was analyzed in gastric NHL stages I and II (histologic subtype not considered showing no significant influence). At 3 and 5 years survival is 88% in resected cases vs. 94% and 86% in conservatively treated patients (p = 0.350). Analyzing only stages I + II(1) surgery also seems of no advantage even considering only RO-resections. There was one acute gastrointestinal bleeding under primary chemotherapy for a high grade lymphoma. Toxicities of grade III and IV WHO were rarely seen during treatment. All other acute toxicities were not more than grade II WHO. CONCLUSION: Conservative treatment in this setting is feasible. The operative approach seems not to be advantageous compared to conservative treatment and should be critically reconsidered.

Adult↗