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K Neben

Publications and source records attributed to K Neben.

13 recordsLinked to original sources
PubMed2004

[Dynamic MRI of the bone marrow for monitoring multiple myeloma during treatment with thalidomide as monotherapy or in combination with CED chemotherapy].

PURPOSE: To quantify changes of bone marrow microcirculation in multiple myeloma (MM) using contrast enhanced dynamic MRI (dMRI) during thalidomide as antiangiogenic monotherapy or in combination with chemotherapy (cyclophosphamide, etoposide, dexamethasone). MATERIALS AND METHODS: The study includes 63 patients with refractory or relapsed MM, who underwent dMRI with high temporal resolution (T1w-turboFLASH) of the lumbar spine before and following treatment. The contrast uptake was quantified using a two compartment model with the output parameters amplitude and k (ep) (exchange rate constant). The evaluation considered the initial dMRI finding (pathological or non-pathological) and the clinical therapeutic response (response or no response). RESULTS: During monotherapy with thalidomide (n = 38), no significant changes of the dMRI parameters were found, even when considering the initial dMRI finding (positive n = 22) and the therapeutic response (responder n = 14). The combination with chemotherapy (n = 25) had a significant reduction of k (ep) (p = 0.01) in 18 patients with positive initial dMRI finding and therapeutic response. Reduction of the amplitude was seen in most cases, but in the end without any significance (p = 0.09). CONCLUSION: dMRI can quantify significant changes of bone marrow microcirculation solely during treatment with thalidomide combined with chemotherapy, not with thalidomide alone.

Administration, Oral↗
PubMed2003

Centrosome aberrations as a possible mechanism for chromosomal instability in non-Hodgkin's lymphoma.

Recently, centrosome aberrations have been described as a possible cause of aneuploidy in many solid tumors. To investigate whether centrosome aberrations occur in non-Hodgkin's lymphoma (NHL) and correlate with histologic subtype, karyotype, and other biological disease features, we examined 24 follicular lymphomas (FL), 18 diffuse large-B-cell lymphomas (DLCL), 33 mantle cell lymphomas (MCL), and 17 extranodal marginal zone B-cell lymphomas (MZBCL), using antibodies to centrosomal proteins. All 92 NHL displayed numerical and structural centrosome aberrations as compared to nonmalignant lymphoid tissue. Centrosome abnormalities were detectable in 32.3% of the cells in NHL, but in only 5.5% of lymphoid cells from 30 control individuals (P<0.0001). Indolent FL and MZBCL contained only 25.8 and 28.8% cells with abnormal centrosomes. In contrast, aggressive DLCL and MCL harbored centrosome aberrations in 41.8 and 35.0% of the cells, respectively (P<0.0001). Centrosomal aberrations correlated to lymphoma grade, mitotic, and proliferation indices, but not to the p53 labeling index. Importantly, diploid MCL contained 31.2% cells with abnormal centrosomes, while tetraploid samples harbored centrosome aberrations in 55.6% of the cells (P<0.0001). These results indicate that centrosome defects are common in NHL and suggest that they may contribute to the acquisition of chromosomal instability typically seen in NHL.

Cell Division↗
PubMed2002

Centrosome replication, genomic instability and cancer.

Karyotypic alterations, including whole chromosome loss or gain, ploidy changes, and a variety of chromosome aberrations are common in cancer cells. If proliferating cells fail to coordinate centrosome duplication with DNA replication, this will inevitably lead to a change in ploidy, and the formation of monopolar or multipolar spindles will generally provoke abnormal segregation of chromosomes. Indeed, it has long been recognized that errors in the centrosome duplication cycle may be an important cause of aneuploidy and thus contribute to cancer formation. This view has recently received fresh impetus with the description of supernumerary centrosomes in almost all solid human tumors. As the primary microtubule organizing center of most eukaryotic cells, the centrosome assures symmetry and bipolarity of the cell division process, a function that is essential for accurate chromosome segregation. In addition, a growing body of evidence indicates that centrosomes might be important for initiating S phase and completing cytokinesis. Centrosomes undergo duplication precisely once before cell division. Recent reports have revealed that this process is linked to the cell division cycle via cyclin-dependent kinase (cdk) 2 activity that couples centriole duplication to the onset of DNA replication at the G(1)/S phase transition. Alterations in G(1)/S phase regulating proteins like the retinoblastoma protein, cyclins D and E, cdk4 and 6, cdk inhibitors p16(INK4A) and p15(INK4B), and p53 are among the most frequent aberrations observed in human malignancies. These alterations might not only lead to unrestrained proliferation, but also cause karyotypic instability by uncontrolled centrosome replication. Since several excellent reports on cell cycle regulation and cancer have been published, this review will focus on the role of centrosomes in cell cycle progression, as well as causes and consequences of aberrant centrosome replication in human neoplasias.

Aneuploidy↗
PubMed2001

Salvage therapy for multiple myeloma with thalidomide and CED chemotherapy.

The feasibility and efficacy of a combination of thalidomide, cyclophosphamide, etoposide, and dexamethasone were studied in 56 patients with poor-prognosis multiple myeloma. Of 50 patients evaluable for response, 4% achieved complete response (CR), 64% partial response (PR), 18% minimal response (MR), 6% stable disease (SD), and 8% progressive disease (PD), resulting in an objective response rate (> or = MR) of 86.0% (76.7% overall objective response rate in intent-to-treat analysis; n = 56). Subsequent to successful remission induction, 18 patients received autologous or allogeneic stem cell transplantation. The median progression-free survival in all patients was 16 months. The median overall survival time could not be calculated, since the last observed death occurred after 16 months of follow-up (median follow-up of 14 months) with a corresponding estimated survival probability of 55%. Severe adverse effects (World Health Organization III/IV) included infectious complications (35.7%) and cardiovascular events (7.1%). The data suggest that Thal improves antitumor activity of salvage chemotherapy regimens in poor-prognosis multiple myeloma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Angiogenesis in hematologic malignancies.

Angiogenesis, defined as the blood vessel generation from preexisting blood vessels, was found to play an important role in the progression of solid tumors. In addition, bone marrow-derived endothelial precursor cells may contribute to tumor angiogenesis. Recently angiogenesis induction was described in several hematologic neoplasms as leukemia, lymphoma, myelodysplastic syndrome and multiple myeloma (MM). Clinical angiogenesis research also termed as angiodiagnosis has established the prognostic relevance of markers of angiogenesis e.g., microvessel density and circulating levels of angiogenic peptides. Development of antiangiogenic treatment for hematologic neoplasms has recently been sparked by the success of Thalidomide (Thal) which has antiangiogenic properties in MM. Antiangiogenic treatment strategies are now being tested in clinical trials on several types of hematologic neoplasms.

Angiogenesis Inhibitors↗
PubMed2001

Bone marrow microcirculation analysis in multiple myeloma by contrast-enhanced dynamic magnetic resonance imaging.

The aim of our study was to investigate the quantitative microcirculation parameters amplitude A (hypothetical intravascular volume) and exchange rate constant k(21) (hypothetical vascular permeability) by contrast-enhanced dynamic magnetic resonance imaging (dMRI) as markers of angiogenesis in multiple myeloma (MM). Therefore lumbar spine and spina iliaca superior posterior of 16 normal controls and 41 patients with active MM were assessed using a dMRI protocol with a pump controlled bolus infusion of Gadolinium-DTPA. Pharmacokinetic parameters, amplitude A and exchange rate constant k(21) were calculated according to a 2-compartment model. Color-coded parameter images were generated from pharmacokinetic data analysis and superimposed onto the conventional MR images. Amplitude A and k(21) parameters were significantly increased in patients with MM compared with controls (p = 0.001; median A(ctr), 0.2 [range, 0.09-0.4]; median A(MM), 0.93 [range, 0.2-2.2]; median k(21ctr), 0.09 min(-1) [range, 0.03-0.9]; median k(21MM), 4.58 [range, 0.22-23.8]). Within the group of MM patients the pattern of color-coded parameter images were found to be either of "diffuse" (n = 13, 31%) or "focal" (n = 28, 69%) type of distribution of microcirculation. Comparison of amplitude A in patients with "focal" vs. "diffuse" pattern of the pharmacokinetic maps revealed a significant increase in the median of amplitude A in the "focal" group. Amplitude A values allowed a classification of patients according to severe osteolytic bone involvement (p = 0.023) with the best cutoff value of 0.7 for amplitude A. Downmodulation of amplitude A was observed in a MM patient treated with standard VAD chemotherapy. Our data demonstrate that dMRI is a novel imaging technique for the detection and monitoring of MM bone lesions. It provides independent evidence for angiogenesis in MM.

Adult↗
PubMed2001

A man with hereditary exostoses and high-grade non-Hodgkin's lymphoma of the bone.

Multiple cartilaginous exostoses (MCE) is an autosomal dominant disorder that can lead to malignant transformation from exostoses to a secondary chondrosarcoma. We present a case report of a 52-year-old man with MCE who had a palpable mass at the left shoulder. At the site of the left proximal humerus, a cartilaginous exostosis was localized, suggesting that the tumor developed by a malignant transformation of an exostosis into a secondary chondrosarcoma. Interestingly, a biopsy showed a diffuse large B-cell lymphoma with Burkitt-like features. To our knowledge, the association of high-grade lymphoma and hereditary exostoses has not been described previously. This case demonstrates that a malignant tumor at the location of a cartilaginous exostosis is not necessarily a chondrosarcoma and that a biopsy is an essential part of the diagnostic work-up.

Bone Neoplasms↗
PubMed2001

Response to thalidomide in progressive multiple myeloma is not mediated by inhibition of angiogenic cytokine secretion.

Thalidomide (Thal) is a drug with anti-angiogenic properties. To explore whether the effect of Thal on angiogenesis is associated with a reduction of angiogenic cytokine levels in progressive multiple myeloma (MM), plasma levels of basic fibroblast growth factor, vascular endothelial growth factor, interleukin 6, tumour necrosis factor-alpha and hepatocyte growth factor (HGF) were measured in 51 patients at 0, 3 and 6 months of Thal therapy. After 6 months of treatment, 26 patients were considered to be responsive to Thal therapy, including 17 minimal responses, eight partial responses and one complete response. Only HGF (decreasing, P = 0.02) in the group of responsive patients showed a statistically significant change over a period of 6 months. Because HGF levels are known to correlate to MM tumour burden, we conclude that the mechanism of action of Thal in MM is not caused by a specific inhibition of angiogenic cytokine secretion.

Adult↗
PubMed2001

High plasma basic fibroblast growth factor concentration is associated with response to thalidomide in progressive multiple myeloma.

The aim of this study was to define prognostic factors that might be predictive for response to thalidomide (Thal) in progressive multiple myeloma (n = 54). We examined the concentration of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), two potent heparin-binding mediators of angiogenesis in peripheral blood (PB; PB-VEGF and PB-bFGF) and bone marrow (BM; BM-VEGF and BM-bFGF), in combination with well-characterized predictors for response and survival to chemotherapy. After a median follow-up time of 15 months (range, 0.3-20), 29 patients (pts.) showed at least a minimal response to Thal therapy, whereas 25 pts. were nonresponsive. As shown by univariate analysis, responsive pts. had statistically significant higher concentrations of PB-bFGF (P = 0.009) and beta2-microglobulin (P = 0.03) before therapy, as well as lower hemoglobin (P = 0.008) and albumin (P = 0.02) levels, whereas no statistically significant difference was found for PB-VEGF (P = 0.93). When a multiple logistic regression analysis was performed, PB-bFGF was the only statistically significant predictor for response to therapy (P = 0.01). None of these variables was associated with a prolonged progression-free survival. In conclusion, our findings indicate that high pretreatment plasma bFGF levels in pts. with progressive multiple myeloma are associated with unfavorable parameters of response and survival but nevertheless predict for response to Thal therapy.

Adult↗
PubMed2000

[Functional magnetic resonance tomography in the diagnosis and therapy monitoring in multiple myeloma].

AIM OF THE STUDY: Investigation of the quantitative microcirculation parameters amplitude A and exchange rate constant k21 determined by contrast-enhanced dynamic magnetic resonance imaging (d-MRI) in multiple myeloma (MM). METHODS: d-MRT of lumbar spine and right spina iliaca superior posterior of 16 controls (ctr) and 35 patients with active MM. Generation of colour-coded images of microcirculation parameters superimposed onto static MRI images. RESULTS: Amplitude A and k21 parameters were significantly increased in patients with MM and down modulated by therapy in 7 of 8 MM cases in a follow-up investigation [p < 0.01; median Actr = 0.2 (0.09-0.4); median AMM = 0.93 (0.2-1.52); median k21ctr = 0.09 min-1 (0.03-0.9); median k21MM = 4.57 min-1 (0.21-23.8)]. Thirteen patients revealed a "diffuse" and 22 a "focal" pattern of distribution of microcirculation parameters. Bone marrow biopsies in 8 cases revealed an correlation between bone marrow plasma cell infiltration and increased microcirculation parameters. CONCLUSION: Identification of microcirculation changes by d-MRI is a novel imaging technique for the detection and monitoring of MM bone lesions.

Antineoplastic Agents, Alkylating↗
PubMed2000

High-dose therapy with peripheral blood stem cell transplantation for patients with relapsed or refractory Hodgkin's disease: long-term outcome and prognostic factors.

From March 1986 to March 1998, 82 patients with relapsed or refractory Hodgkin's disease underwent high-dose chemotherapy (HDCT) with peripheral blood stem cell (PBSC) transplantation in our center. This is a retrospective analysis of the long-term clinical outcome. There were 52 males and 30 females with a median age of 32 years (range 18-59 years). Prior to transplantation, 36 patients were in complete remission (CR), 34 in partial remission (PR), and 12 had refractory disease after salvage therapy. For HDCT, 78 patients were treated with CBV (cyclophosphamide, 6.0-6.8 g/ m2; etoposide, 1.0-1.6 g/m2; carmustine, 0.45-0.8 g/m2), while four patients received different regimens. Probability of freedom from progression (FFP), overall survival (OS), and event-free survival (EFS) at 5 years of the entire group was 63%, 61%, and 54%, respectively. Early mortality rate ( < or = 100 days) declined from 17% to 6% after 1992. Five patients died of late transplant-related complications (> 100 days), including secondary lymphoma and leukemia in two patients. None of the refractory patients survived beyond 3.5 years. Multivariate analyses identified extranodal sites of disease at relapse and refractory disease status prior to transplantation as significant prognostic factors for FFP, EFS, and OS. As we have shown in our study, remarkable progress was achieved in reducing early morbidity and mortality over time, but this was associated with only a slight, not significant improvement of long-term outcome (OS 66% vs 57% at 5 years for patients undergoing PBSC transplantation before and after 1992, P = 0.26). Although the results as a whole are encouraging for chemosensitive patients, new therapeutic strategies are needed to reduce toxicity and improve the clinical outcome of patients, especially of those with a less favorable prognosis.

Adolescent↗
PubMed1999

Impaired thymopoietic potential of immature CD3(-)CD4(+)CD8(-) T cell precursors from SIV-infected rhesus monkeys.

Immature thymocyte subpopulations were examined for their capacity to differentiate in a newly developed xenogeneic monkey-mouse fetal thymus organ culture (FTOC) system. We provide evidence for impaired precursor function of CD3(-)CD4(+)CD8(-) thymocytes after in vivo infection with SIVmac251 as indicated by a reduced cell number per FTOC and a lower percentage of thymocytes with more mature phenotypes. Addition of recombinant SIV glycoprotein 120 (rgp120) also resulted in a dose-dependent impairment of T cell maturation in FTOC. The data suggest that in patients infected with HIV, T cell maturation and thus replenishment of peripheral pools may be compromised as a result of intrathymic infection or circulating viral gp120.

Animals↗