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Biomedical subjects

A Ganser

Publications and source records attributed to A Ganser.

At least 55 records · Page 3Linked to original sources
PubMed2002

Increased risk of complicated CMV infection with the use of mycophenolate mofetil in allogeneic stem cell transplantation.

Mycophenolate mofetil (MMF) is increasingly used for prophylaxis and therapy of GVHD in allogeneic stem cell transplantation. In some recent reports of use of MMF in solid organ transplantation a high incidence of CMV disease has been described. We evaluated the frequency and course of active CMV infection in patients who received MMF compared to those who did not receive MMF after allogeneic stem cell transplantation. We retrospectively analyzed 48 adult patients who consecutively underwent unmanipulated allogeneic bone marrow (n = 15) or peripheral stem cell transplantation (n = 33) from HLA-compatible family donors (n = 30) or unrelated donors (n = 18) from February 1997 to September 2000 at our institution. Only patients who were evaluable for the first 100 days were included in this analysis. Sixteen patients received MMF post transplant (MMF+). CMV-antigenemia was monitored by CMV-pp65 antigen. CMV-antigenemia occurred in 14 patients and was virtually only observed in CMV-IgG+ recipients (13/23, 56%). CMV-IgG+/MMF+ patients developed a higher incidence of CMV-antigenemia (8/9, 89%) compared to the CMV-IgG+/MMF- patients (5/14, 35%; P < 0.05). Moreover, five of six patients with persistent or recurrent CMV-antigenemia received MMF. No patient in either group developed CMV disease or died of CMV-related complications. In multivariate analysis including MMF treatment, unrelated vs related donor, GVHD, CMV-serostatus of the donor and stem cell graft type, only MMF treatment was found to be a significant risk factor for both overall and complicated CMV infection.

Adult↗
PubMed2002

Efficient gene transfer into the CNS by lentiviral vectors purified by anion exchange chromatography.

Lentiviral vectors have been shown to stably transduce dividing and non-dividing target cells in vitro and in vivo. However, in vivo gene transfer applications with viral vectors in the central nervous system require highly efficient vector preparations, because only very small volumes can be injected stereotactically without damage to the brain tissue. Since lentiviral vectors are generated in transient co-transfection systems, viral preparations need to be purified and efficiently concentrated before injection into the brain. We describe an alternative procedure to concentrate lentiviral preparations by binding viral particles to an anion exchange column. Viral particles are eluted with sodium chloride, desalted and further concentrated by ultrafiltration. These vector preparations allowed high levels of gene transfer into terminally differentiated neuronal and glial cells and long-term transgene expression without any signs of acute and long-term toxicity or inflammation. The purification of lentiviral vectors from large-scale preparations by anion exchange chromatography allowed us to concentrate the virus to small volumes and to use these preparations to genetically modified target cells in vivo without signs of acute inflammatory responses.

Animals↗
PubMed2002

Central venous catheter infections in patients with acute leukemia.

BACKGROUND: Central venous catheters (CVCs) have become an essential tool for an appropriate management of patients with acute leukemia. Infectious complications are a major concern in patients treated for acute leukemia. Although CVC-related infections are considered to be a major source of infections during neutropenia (<500/microl), data regarding the incidence of CVC-related infections are rare in acute leukemia. PATIENTS AND METHODS: We analyzed nontunneled CVCs in 58 patients with acute leukemia (22 men/36 women) in 119 chemotherapy cycles from April 1996 to January 1998 in a prospective trial. Proven CVC-related infection was defined as the isolation of the same organism from peripheral blood and CVC tip. CVC infection was suspected or possible when exit site inflammation and positive blood culture or organisms typical for CVC infection were observed. RESULTS: Mean neutropenia/cycle was 16.3 days (SD 8.0). 178 CVCs with 2,576 CVC days (mean 14.5 days, SD 7.2 days) were used in 119 cycles. Fever occurred in 87 cycles (73%). Blood stream infection was proven in 31 out of 87 febrile episodes (26.1%) with 40 isolates (8 gram-negative, 31 gram-positive, 1 Candida spp.). Colonization of the CVC tip was observed in 24 CVC lines with 28 isolates (27 gram-positive, 1 gram-negative); however, proven CVC-related infections were observed in 5 episodes only, all with coagulase-negative staphylococci. In another 6 episodes, CVC-related infection was assumed (local inflammation and gram-positive blood culture). Six further episodes had typical blood isolates (4 coagulase-negative staphylococci, 1 Candida spp.) and were considered possible CVC-related infections. In none of the remaining afebrile 32 cycles was a CVC infection observed or suspected. CONCLUSION: Gram-positive organisms contributed to the majority of CVC-related infections (16 out 17 CVC infections); however, the overall incidence of CVC infections in acute leukemia patients was 6.5/1,000 CVC days only (1.9 proven/2.3 suspected/2.3 possible/1,000 CVC days).

Adult↗
PubMed2001

Inhibition of granulocyte-macrophage colony-stimulating factor receptor function by a splice variant of the common beta-receptor subunit.

The receptors for human granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3), and IL-5 are composed of a ligand-specific alpha-chain (eg, alpha-GM-CSF receptor [alpha-GMR]) and a common beta-subunit (beta-GMR). Ligand binding is believed to induce assembly or conformational changes in preformed complexes containing more than one alpha- and beta-subunit in the activated receptor complex. To analyze the function of a splice variant of beta-GMR with a truncation in the intracellular domain (beta-GMR(IT)), BaF-3 cells expressing human alpha-GMR plus beta-GMR were transfected with beta-GMR(IT). In these cells, coexpression of beta-GMR(IT) inhibits GM-CSF-mediated survival and proliferation in a GM-CSF concentration-dependent manner. To analyze the effect of cytoplasmic assembly of truncated and full-length intracellular beta-GMR sequences, beta-GMR and beta-GMR(IT) were coexpressed with different chimeric alpha/beta-GMR constructs. Whereas both beta-GMR and beta-GMR(IT) generate high-affinity GMR complexes in the presence of alpha/beta-GMR, beta-GMR(IT) inhibits while beta-GMR supports proliferation and cell survival mediated by alpha/beta-GMR. Correspondingly, beta-GMR, but not beta-GMR(IT), generates functional GMR complexes when coexpressed with a defective alpha/beta-GMR construct. These data indicate that beta-GMR(IT) can inhibit survival and mitogenic signaling of the wild-type GMR and demonstrate that recruitment of alternatively spliced receptor subunits may regulate the function of heteromeric cytokine receptors.

Alternative Splicing↗
PubMed2001

[Multilocular Castleman's Disease of the mixed type. An rare differential diagnosis in lymphadenopathy with weakness, weight loss and night-sweats].

HISTORY AND CLINICAL FINDINGS: A 36 years old nurse had been suffering from prolonged weakness, weight-loss of 6 kg, night-sweat and painful swelling of neck lymph nodes for one year. On admission she was in a reduced physical condition. Nuchal, cervical and inguinal lymphnodes were enlarged bilaterally. INVESTIGATIONS: Computed tomography showed enlarged lymph nodes in the neck and inguinally. Histology of the biopsies revealed the diagnosis of the mixed variant of Castleman's Disease. TREATMENT AND COURSE: A steroid treatment was initiated, administering 100 mg prednisone for 2 weeks, 75 mg for another 2 weeks and 50 mg for a month. The dose was then gradually reduced by steps of 10 mg. After 3 months the patient's physical state and lymph nodes were normalized. So treatment was terminated and the nurse was able to take up work again. CONCLUSION: If confronted with general lymphadenopathy associated with B-symptoms even without fever a Castleman's Disease should be taken into consideration. The prognosis of the multivariant form is uncertain. Transformation to malignant lymphoma is frequent.

Adult↗
PubMed2001

Detection and quantification of CBFB/MYH11 fusion transcripts in patients with inv(16)-positive acute myeloblastic leukemia by real-time RT-PCR.

We used a newly established real-time RT-PCR assay for the quantification of the leukemia-specific CBFB/MYH11 transcripts in inv(16)-positive acute myeloblastic leukemia. CBFB/MYH11 could be quantified over a five log range, with a detection limit of 10 molecules of a CBFB/MYH11 plasmid and a 1:10(5) dilution of RNA of the inv(16)-positive ME-1 cell line, respectively. The fusion transcripts were also quantified in 19 patients with acute myeloblastic leukemia and an inv(16) at initial diagnosis. The expression of CBFB/MYH11 varied over a two log range without correlation to clinical response or relapse rate. In nine patients, CBFB/MYH11 was also quantified during/after chemotherapy and autologous or allogeneic stem cell transplantation. All of these patients showed a similar decline of CBFB/MYH11 after intensive therapy. Six of these patients are in complete remission with a stable low-level or absent CBFB/MYH11 expression. Three patients relapsed, and their CBFB/MYH11 transcripts rose again to pretreatment levels. In two patients, this increase in CBFB/MYH11 could be detected by real-time PCR before hematological relapse. These data indicate that real-time RT-PCR can be used for the sensitive detection and quantification of CBFB/MYH11 transcripts in the follow-up of patients with inv(16)-positive AML.

Chromosome Inversion↗
PubMed2001

Detection of antisense and ribozyme accessible sites on native mRNAs: application to NCOA3 mRNA.

The efficacies of antisense oligonucleotides and ribozymes are greatly dependent on the accessibility of their mRNA targets. Target site accessibility is affected by both RNA structure and the proteins associated along the length of the RNA. To mimic the native state of mRNA for site identification, we have previously used endogenous mRNAs in cellular extracts as targets for defined sequence oligodeoxynucleotides (ODNs) designed to identify both antisense pairing and potential ribozyme cleavage sites. The rationale for this approach is that the specific pairing of an ODN with a mRNA forms a DNA:RNA hybrid that is cleaved by the endogenous RNaseH in the cell extract. To extend the usefulness of this basic approach, we report here the use of semi-random ODN libraries to identify hammerhead ribozyme cleavage sites. Thus, the most accessible sites for antisense and ribozyme base pairing are selected by this approach. A novel feature of the approach described here is the use of terminal transferase-dependent PCR (TDPCR) after reverse transcription to estimate the cleavage efficiency and to precisely determine the RNaseH and ribozyme cleavage sites on mRNAs in cell extracts following treatment with ODN or ribozyme libraries. As a model system, we have targeted the NCOA3 (also known as AIB-1) mRNA in cell extracts. The NCOA3 mRNA encodes a nuclear receptor co-activator that is amplified and over-expressed in a high proportion of breast and ovarian cancers. A highly accessible site on this mRNA was identified, and a ribozyme targeted to this site was demonstrated to effectively downregulate NCOA3 function in cells.

Base Pairing↗
PubMed2001

Evolving treatment options of myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) comprise a heterogenous group of myeloid stem cell disorders characterized by peripheral cytopenias and dysplasia of bone marrow progenitor cells. A clonal evolution can result in progressive bone marrow failure and transformation towards acute myelogenous leukemia. A patient's prognosis as estimated by the International Prognostic Scoring System, age, and co-morbidities have to be considered for the selection of various treatment options. Although supportive care remains standard therapy for low-risk MDS, a number of treatment approaches that aim to improve cytopenia in transfusion-dependent patients are currently under investigation. Among others, immunosuppressive, anticytokine, and antiangiogenic therapy will be discussed. The demethylating agents 5-azacytidine and decitabine are promising for the treatment of elderly patients with high-risk MDS. An increase of the upper age limit for allogeneic stem cell transplantation, the only curative treatment option, by the development of dose-reduced conditioning regimens may have implications for the treatment of MDS patients in the future.

Adult↗
PubMed2001

Safe administration of irinotecan, oxaliplatin and raltitrexed in a DPD-deficient patient with metastatic colon cancer.

Dihydropyrimidine dehydrogenase deficiency is diagnosed more frequently and is now generally accepted as a potentially life-threatening condition. It predisposes patients receiving treatment with fluoropyrimidines such as 5-fluorouracil (5-FU) to severe and, in case of complete dihydropyrimidine dehydrogenase deficiency, often fatal toxicity. A patient who had severe side effects following standard dose adjuvant 5-FU exposure was diagnosed of having hereditary partial dihydropyrimidine dehydrogenase deficiency. When the patient relapsed with liver metastases, we treated him with the non-fluoropyrimidine cytotoxic agents irinotecan, oxaliplatin and raltitrexed in sequential manner, and were able to show that these drugs can be safely applied in patients with this metabolic defect.

Adenocarcinoma↗
PubMed2001

Donor cell-derived acute myeloid leukemia developing 14 months after matched unrelated bone marrow transplantation for chronic myeloid leukemia.

We report a patient with Ph-positive CML who developed a Ph-negative AML in donor cells 14 months after BMT from an HLA-identical male unrelated donor. The Ph translocation could not be detected by either conventional cytogenetics, FISH or RT-PCR analysis excluding relapse of CML in myeloid blast crisis. Chimerism studies were performed by variable number of tandem repeats (VNTR) analysis. These revealed donor-type hematopoiesis in both unseparated mononuclear cells and CD34+ selected blasts proving the leukemia to be of donor origin. The patient received three cycles of polychemotherapy with mitoxantrone, topotecan and ara-c resulting in CR after the first treatment cycle and reconstitution with donor hematopoiesis. A second transplant from a female alternative matched unrelated donor was performed after conditioning with fludarabine and 200 cGy TBI and was well tolerated. Nine months after the second transplant the patient is at home and in CR. T cell chimerism was studied by sex chromosome analysis and revealed complete female donor chimerism.

Adult↗
PubMed2001

HLA phenotype and cytokine-induced tumor control in advanced renal cell cancer.

BACKGROUND: The natural history of malignancies, the response to cytokine-based therapy and survival of patients may be partly determined by the human leukocyte antigen (HLA) phenotype. Here, we investigated in a retrospective analysis the correlation of the HLA phenotype of 73 prognostic favored patients with advanced renal cell carcinoma to (a) the expected HLA distribution in Caucasians, (b) the susceptibility or resistance to metastatic sites, (c) response to cytokine-based therapy and (d) sustained cytokine-induced effective tumor control. METHODS: We retrospectively determined the MHC class I and II antigens in patients with metastatic renal cell carcinoma selected by survival. Antigens were serologically typed by standard lymphocytotoxicity techniques. For statistical analysis, we calculated the probability of the presented HLA antigens in correlation to the expected Caucasian HLA phenotypes. An independent confirmation was performed by using the chi-square and two-tailed Fisher's exact test. RESULTS: Various HLA antigens deviated significantly from the normal distribution in the Caucasian population. HLA.B44 was the only antigen associated (p < 0.01) with the absence of lung and presence of bone metastases, while it did not impact on overall survival or response to therapy. A1 (p < 0.0001, p < 0.002) and B8 (p < 0.009, p < 0.04) alleles were more frequently expressed in responding patients than expected from the normal distribution in Caucasians and that observed in non-responding patients, respectively. The HLA analysis of patients achieving a durable complete remission showed a significantly higher frequency of expression of the A1 and B8 antigens and furthermore of the B14 antigen (p < 0.05). CONCLUSIONS: Our data underline the pivotal role of the MHC complex in controlling and regulating the cellular immune response in renal cell cancer. We could identify HLA antigens, which correlate with response to cytokine-treatment, with a long-lasting effective tumor control and prolonged overall survival.

Adult↗
PubMed2001

Receptor-mediated endocytosis of CD34 on hematopoietic cells after stimulation with the monoclonal antibody anti-HPCA-1.

CD34 most probably acts as a receptor molecule on hematopoietic progenitor cells; however, its precise function remains to be elucidated. To track the intracellular pathway of CD34 after binding of a stimulatory antibody (anti-HPCA-1), immuno-electron microscopical analysis was performed on cells of normal bone marrow (NBMPC), acute leukemias, and the KG1a cell line. Before stimulation, CD34 was evenly distributed over the cell surface. After binding of the anti-HPCA-1, but not the anti-HPCA-2 antibody to CD34 and labeling with 30-nm immunogold, a rapid capping of CD34 and a subsequent internalization from the cell surface via clathrin-coated pits and coated vesicles was observed. The percentage of internalized CD34/immunogold complexes ranged from 8 to 80% in the NBMPC and the leukemic blasts, whereas KG1a cells showed an internalization rate of only 0.42%. Moreover, in the KG1a cells, the CD34/immunogold complexes were not associated with the coated pits. These differences in CD34 internalization did not correlate to the mRNA expression for the full-length or truncated CD34 assessed by isotype-specific real-time PCR. Taken together, evidence was found that CD34 is a surface receptor molecule that is modulated by receptor-mediated endocytosis. CD34 on KG1a cells appears to have a functional and/or structural defect, preventing modulation of this epitope.

Acute Disease↗
PubMed2001

Tissue factor and thrombomodulin levels are correlated with stage of cirrhosis in patients with liver disease.

Liver cirrhosis is associated with alterations of the coagulation system commonly causing bleeding as well as thromboembolic complications. The potential pathophysiological roles of tissue factor (TF) (the initiator of the extrinsic coagulation pathway) and thrombomodulin (TM) (an initiator of the anticoagulatory protein C pathway) are unknown. We therefore measured plasma concentrations of TF and TM in 111 patients with liver diseases who were evaluated for liver transplantation. We could demonstrate that the levels of both molecules increased with the Child's class of liver cirrhosis, independently of aetiology. TM was significantly elevated in Child A, B and C patients compared with patients without cirrhosis; TF only in Child C patients. The plasma TM and TF concentrations correlated with prothrombin time, activated partial thromboplastin time, and inversely with factor VII activity, cholinesterase serum activity, and serum albumin concentration. TM was elevated in patients with a bleeding tendency, but TM and TF did not differ between patients with or without prior thrombotic events. Further studies are warranted to clarify the underlying mechanisms that raise TM and TF plasma levels in liver disease with possible clinical consequences.

Adolescent↗
PubMed2001

Quantification and facilitated comparison of von Willebrand factor multimer patterns by densitometry.

The analysis of von Willebrand factor (vWF) multimers is an important laboratory tool for distinguishing among the numerous subtypes of von Willebrand disease (vWD). Comparability and reproducibility of this method are insufficient; standardization and external references are pending. Interlaboratory comparison of results therefore may be difficult. We applied densitometry to obtain a reproducible quantification of vWF multimer patterns in healthy donors, patients with vWD variants, and factor VIII/vWF concentrates to improve the reproducibility and comparability of vWF multimer analysis. Multimers were separated and visualized luminographically on x-ray films. Films were scanned and evaluated by densitometry. The variation inherent in vWF multimer analysis and the range of the normal could be quantified. In vWD variants and factor VIII/vWF concentrates, densitometry could quantify and visualize alterations of vWF multimer patterns and facilitate their comparison. Densitometry permits a precise quantitative comparison of sample patterns to a reference plasma. It could be a valuable tool offering reproducible quantification and additional visualization of normal and pathologic vWF multimer patterns, facilitating their comparison and contributing to a standardization of vWF multimer analysis.

Adult↗
PubMed2001

Quantitative determination of lentiviral vector particle numbers by real-time PCR.

Here, we describe a quantitative, DNA-based, real-time PCR approach to determine the number of lentivirus particles that are present in vector preparations. In this approach, the minus strong-stop cDNA fragment that is present in viral capsids serves as template for PCR. Using this technology, we found that only 0.1%-1% of the virus particles that are present in vector preparations are infectious. The approach described here is rapid, reliable, and simple in concept and can be used to estimate both vector particles in supernatants and the number of infectious particles. Also, this approach can easily be adapted to a high-throughput system by using 96-well plates and a 2-h running time.

Genetic Vectors↗
PubMed2001

Prevalence of a 23bp insertion in exon 3 of the endothelial cell protein C receptor gene in venous thrombophilia.

BACKGROUND: The endothelial cell protein C receptor (EPCR) enhances protein C activation by the thrombin-thrombomodulin complex. As evidence is accumulating that EPCR is an important component of the protein C anticoagulant pathway, polymorphisms in the EPCR gene might be candidate risk factors predisposing to venous thromboembolism (VTE). Recently, a 23bp insertion in exon 3 of the EPCR gene has been identified, which duplicates the preceding 23 bases and results in a STOP codon downstream from the insertion point. However, the clinical significance of this mutation in VTE remains to be clarified. METHODS AND RESULTS: In this study we evaluated the EPCR 23bp insertion in 889 patients with documented VTE and in 500 healthy controls. The prevalence of the EPCR insertion among patients was 0.1%, which was not significantly different compared to controls (0.6%, p = 0.1). CONCLUSIONS: Our findings showed that the EPCR 23bp insertion is very rare in both patients with VTE and the general population and failed to support an association between the EPCR 23bp insertion and an increased risk of VTE.

Adult↗
PubMed2000

Increased lipoprotein (a) levels as an independent risk factor for venous thromboembolism.

Elevation of serum lipoprotein (a) (Lp[a]) is a known risk factor predisposing to cardiovascular and cerebrovascular disease. However, little is known about the role of increased Lp(a) in venous thromboembolism (VTE). This study evaluated the role of Lp(a) among a panel of established hereditary thrombogenic defects in patients with VTE. A total of 685 consecutive patients with at least one episode of VTE and 266 sex- and age-matched healthy controls were screened with regard to activated protein C resistance, protein C, protein S, and antithrombin deficiency, elevated serum levels of Lp(a), and the factor V G1691A, MTHFR C677T, and prothrombin G20210A mutations. Elevated Lp(a) levels above 30 mg/dL were found in 20% of all patients, as compared to 7% among healthy controls (P <.001, odds ratio [OR] 3.2, 95% confidence interval [CI], 1.9-5.3). The coexistence of FV G1691A and elevated Lp(a) was significantly more prevalent among patients with VTE than in the control group (7% versus 0.8%; P <.001, OR 9.8, 95% CI, 2.4-40.7). No other established prothrombotic risk factor was found to be significantly combined with increased Lp(a). These data suggest that Lp(a) concentrations greater than 30 mg/dL are a frequent and independent risk factor for VTE. Furthermore, elevated Lp(a) levels might contribute to the penetrance of thromboembolic disease in subjects being affected by other prothrombotic defects, such as FV G1691A mutation.

Adolescent↗