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G Gahrton

Publications and source records attributed to G Gahrton.

At least 19 recordsLinked to original sources
PubMed2001

Expression and release of stable and active forms of murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) targeted to different subcellular compartments.

Cytokines have been used for several years as immunomodulators. However, one of the main drawbacks of systemically applied cytokines is their high toxicity. In addition, cytokines work in a paracrine form and frequently after cell-to-cell interaction. Therefore, a very restricted release of cytokines-in time and space-could be desired for most of their therapeutic applications. The murine granulocyte-macrophage colony-stimulating factor (mGM-CSF) is one of the most promising cytokine candidates for cancer immunotherapy and as an adjuvant of DNA vaccines. With the aim of improving the administration and release of cytokines in a very restricted area, we have designed vectors expressing the mGM-CSF cDNA with different localization signals. Using this strategy we have shown that cytokines can be expressed and targeted to different subcellular compartments (i.e. the cytoplasm, the endoplasmic reticulum and the nucleus), stored inside the cells and released after cell lysis as stable active proteins. Moreover, a plasma membrane targeted form of mGM-CSF displayed substantial amount of biological activity. These vectors could have potential applications in immunotherapy for tumours and DNA vaccination protocols.

Animals↗
PubMed2001

Proximal promoter of the murine syndecan-1 gene is not sufficient for the developmental pattern of syndecan expression in B lineage cells.

Syndecan-1 (CD138) is a cell membrane proteoglycan that binds extracellular matrix components and various growth factors. The role of syndecan-1 in the control of cell growth and morphology has been illustrated by its altered expression in hematological malignancies such as multiple myeloma as well as some solid tumors. It has been reported that the expression of syndecan-1 in cells of the B lineage is developmentally regulated such that pre-B cells and plasma cells express syndecan-1 while mature B cells do not. Thus, we investigated whether the proximal promoter region of the murine syndecan-1 promoter was able to confer the observed on-off-on expression of syndecan-1 in cells of the B lineage as they develop from pre-B cells to plasma cells. Experiments carried out using deletion mutants of the proximal promoter cloned upstream of the CAT reporter gene transfected into murine cell lines, representing the above stages of B-cell development, such as BA/F3 (pro-B cell), 70Z/3 (pre-B cell), 2PK3 (late mature B cell), and MPC-11 (plasma cell), showed detectable levels of CAT expression. The WEHI-231 (mature B cell) cell lines did not show detectable levels of CAT reporter activity. The strong levels of expression were observed with a fragment of the proximal promoter spanning the region from -365 to -95 (from the translation start point). However, Northern analysis of RNA obtained from the five murine B-cell lines, representing various stages of B-cell development, showed that the 70Z/3, MPC-11 but not BA/F3, and 2PK3 cells expressed detectable levels of syndecan-1 mRNA. By FACS analysis, using a rat anti mouse syndecan-1 antibody, syndecan-1 expression on the cell surface was found to correlate with the observed mRNA expression patterns in these cell lines. Our results indicate that the proximal promoter of the murine syndecan-1 promoter is not sufficient for the observed developmental pattern of syndecan expression in B cells.

Animals↗
PubMed2001

Alpha-interferon maintenance treatment is associated with improved survival after high-dose treatment and autologous stem cell transplantation in patients with multiple myeloma: a retrospective registry study from the European Group for Blood and Marrow Transplantation (EBMT).

The purpose of this study was to evaluate the effect of alpha-IFN maintenance treatment after autologous stem cell transplantation (ASCT) for multiple myeloma in a retrospective registry analysis. 473 patients with multiple myeloma who received IFN maintenance treatment ASCT were compared with 419 patients who did not receive IFN-treatment. Patients who were evaluable for response and in complete or partial remission at 6 months after ASCT were eligible, after excluding patients with graft failure. Cox proportional hazards assumptions were checked and handled by stratification. The prognostic variables unevenly distributed between the two groups were statistically corrected for in the Cox analysis. 391 patients reached complete remission (CR) after ASCT (203 in the IFN group and 188 in the no-IFN group) and 501 were in partial remission (PR, IFN 270, no-IFN 231). Overall survival (OS) and progression-free survival (PFS) were significantly better in the IFN-group (OS, 78 vs 47 months, P = 0.007, and PFS, 29 vs 20 months, P = 0.006, respectively). The difference in OS and PFS was most strongly pronounced in the PR patients. 209 patients have died (IFN, 84; no-IFN, 125). Progressive myeloma was the cause of death in 94% of the IFN-treated patients and in 83% of the no-IFN group (P = NS). Thus, IFN maintenance treatment after ASCT was associated with better OS and PFS. Treatment seemed to be most beneficial in patients who did not achieve CR. The difference in median survival was as long as 2.5 years, and although part of this difference is attributable to differences in other prognostic factors, it might justify possible differences in quality-of-life due to adverse effects of interferon treatment.

Adolescent↗
PubMed2001

Mapping of herpes simplex virus-1 VP22 functional domains for inter- and subcellular protein targeting.

The herpes simplex virus 1 (HSV-1) tegument protein VP22 has been utilised as a vehicle for trafficking proteins. It has a remarkable property of exiting the cell that is producing it and entering the neighbouring cells, which has been used to deliver therapeutic proteins, p53 and herpes simplex virus thymidine kinase (tk). It has a complex pattern of expression and subcellular localisation. Functions of VP22 include intercellular transport, binding to and bundling of microfilaments, inducing cytoskeleton collapse, nuclear translocation during mitosis, and binding to chromatin and nuclear membrane. The regions of VP22 which contain each of these functions have not been characterised. Finding the region carrying the property of intercellular spread would facilitate enhancement of transport function. By constructing a series of deletion constructs of VP22 tagged by the green fluorescent protein (GFP) we have mapped the functions of VP22 to specific regions in the polypeptide as follows: intercellular transport - aa 81-195; binding and reorganisation of cytoskeleton - aa 159-267; nuclear targeting, inhibition of cytoskeleton collapse - aa 81-121; and nuclear targeting and facilitation of intercellular transport - aa 267-301. Separation of VP22 functions enables focus on the mechanism of VP22-mediated transport and improve the transportation efficiency of VP22.

Animals↗
PubMed2001

Progress in allogenic bone marrow and peripheral blood stem cell transplantation for multiple myeloma: a comparison between transplants performed 1983--93 and 1994--8 at European Group for Blood and Marrow Transplantation centres.

Out of 690 allogeneic matched sibling donor transplants for multiple myeloma reported to the European Group for Blood and Marrow Transplantation (EBMT) registry, 334 were performed during the period 1983-93 (all with bone marrow) and 356 during 1994-98 [223 with bone marrow and 133 with peripheral blood stem cells (PBSCs)]. The median overall survival was 10 months for patients transplanted during the earlier time period and 50 months for patients transplanted with hone marrow during the later period. The use of PBSCs was associated with earlier engraftment but no significant survival benefit compared to bone marrow transplants during the same time period. The improvement in survival since 1994 with the result of a significant reduction in transplant-related mortality, which was 38%, 21% and 25% at 6 months and 46%, 30% and 37% at 2 years during the earlier period, and the later period with bone marrow and PBSCs respectively. Reasons for the reduced transplant-related mortality appeared to be fewer deaths owing to bacterial and fungal infections and interstitial pneumonitis, in turn a result of earlier transplantation and less prior chemotherapy. Better supportive treatment and more frequent use of cytokines may also play a role. The improvement in survival was not directly related to the increased use of PBSCs.

Adult↗
PubMed2001

Introduction.

Explore the source record for details and available documents.

Gene Transfer Techniques↗
PubMed2001

Suicide gene therapy: possible applications in haematopoietic disorders.

Although the treatment results for some forms of haematologic malignancies are excellent, especially for the childhood acute leukaemias, there is still a significant fraction of patients that will not benefit from the therapy available today. The identification of new techniques, such as gene therapy, may therefore be of great importance for future therapeutic applications. Suicide gene therapy is one of several gene therapeutic approaches to treat cancer. A suicide gene is a gene encoding a protein, frequently an enzyme, that in itself is nontoxic to the genetically modified cell. However, when a cell is exposed to a specific nontoxic prodrug, this is selectively converted by the gene product into toxic metabolites that kill the cell. The suicide gene most commonly employed, both in experimental and a clinical settings, is herpes simplex thymidine kinase (HSVtk). Some suicide gene products also induce a so-called 'bystander effect', i.e. a toxic effect on adjacent nongene modified tumour cells and sometimes also on more distant tumour cells. The bystander effect is most evident in tumour cells that have a high number of gap junctions, cellular channels build up by proteins called connexins. Many tumours, amongst them many haematological ones, have a low number of gap junctions. Therefore, it is important to develop gap junction independent drug delivery systems. Suicide gene technology may also be used for the ex vivo purging of tumour cells in bone marrow or peripheral blood stem cell autografts or for inactivation of effector cells, such as antitumour T donor lymphocytes in allogeneic transplantation to prevent severe graft versus host reactions. New constructs, e.g. combining suicide genes and immune response enhancing genes or suicide genes and connexin inducing genes may further improve the value of suicide gene therapy.

Animals↗
PubMed2000

Comparative sequence analysis of a region on human chromosome 13q14, frequently deleted in B-cell chronic lymphocytic leukemia, and its homologous region on mouse chromosome 14.

Previous studies have indicated the presence of a putative tumor suppressor gene on human chromosome 13q14, commonly deleted in patients with B-cell chronic lymphocytic leukemia (B-CLL). We have recently identified a minimally deleted region encompassing parts of two adjacent genes, termed LEU1 and LEU2 (leukemia-associated genes 1 and 2), and several additional transcripts. In addition, 50 kb centromeric to this region we have identified another gene, LEU5/RFP2. To elucidate further the complex genomic organization of this region, we have identified, mapped, and sequenced the homologous region in the mouse. Fluorescence in situ hybridization analysis demonstrated that the region maps to mouse chromosome 14. The overall organization and gene order in this region were found to be highly conserved in the mouse. Sequence comparison between the human deletion hotspot region and its homologous mouse region revealed a high degree of sequence conservation with an overall score of 74%. However, our data also show that in terms of transcribed sequences, only two of those, human LEU2 and LEU5/RFP2, are clearly conserved, strengthening the case for these genes as putative candidate B-CLL tumor suppressor genes.

Animals↗
PubMed2000

Mutagen exposures and chromosome 3 aberrations in acute myelocytic leukemia.

Thirteen patients with acute myelocytic leukemia (AML) and with clonal aberrations involving chromosome 3 were studied. Three patients had monosomy 3, four had trisomy 3, and six had structural aberrations of chromosome 3. In the majority of cases chromosome 3 aberrations were parts of complex karyotypes, but in two patients, the abnormalities appeared as single aberrations, one as an interstitial deletion del(3)(p13p21) and the other as monosomy 3. All breakpoints of chromosome 3 were found in the fragile site regions 3p14.2, 3q21 and 3q26-27. All patients with monosomy 3 or structural aberrations of chromosome 3 and one of the four patients with trisomy 3 had been exposed to mutagens, such as occupational exposures to organic solvents and/or petroleum products or treatments with irradiation or antineoplastic agents. The association among mutagen exposure, structural chromosome 3 aberrations and fragile sites in AML may indicate that targeting of the mutagens to these sites is of importance for the etiology of the disease. Leukemia (2000) 14, 112-118.

Adolescent↗
PubMed2000

Progress in haematopoietic stem cell transplantation for multiple myeloma.

High-dose myeloablative treatment followed by autologous haematopoietic stem cell transplantation has significantly improved survival of patients younger than 65 years of age with multiple myeloma as compared with conventional chemotherapy. However, all patients seem to relapse and molecular remissions are rare. Results of allogeneic transplantation, still hampered by high transplant-related mortality, have improved dramatically over the last 5-6 years and this is an option for patients younger than 50-55 years old. The relapse rate is lower than with autologous transplantation and molecular remissions are frequent. Some patients are still in complete haematological remission more the 10 years following transplantation. Autologous transplantation followed by nonmyeloablative allogeneic transplantation is on trial and may be a way to eventually cure a fraction of younger patients with multiple myeloma.

Combined Modality Therapy↗
PubMed1999

Molecular analysis of the human chromosome 5q13.3 region in patients with hairy cell leukemia and identification of tumor suppressor gene candidates.

The pathogenesis of hairy cell leukemia (HCL) remains largely unknown since no specific genetic lesion has been identified in this disease. Previous cytogenetic analysis from our group has shown that chromosome abnormalities involving the 5q13 band are common in HCL, occurring in approximately 1/3 of patients. The data suggest that the 5q13.3 band is likely to harbor a gene involved in the transformational events of this disease. We have recently found two cosmids flanking the 5q13.3 breakpoint in patients with HCL, and the distance between them is approximately 35 kb, as analyzed by fiber-FISH. The two cosmids have been located between the markers SGC34998 and WI-15505/WI-6897 by radiation hybrid mapping. Five of 11 patients with HCL had a hemizygous deletion of the two cosmids, indicating that the function of a tumor suppressor gene may be lost. With the aim of delineating the critical region of 5q13.3 loss in patients with HCL, we have constructed an integrated contig of YAC, BAC, PAC, P1, and cosmid clones that covers the region. Within this area, three expressed sequences were identified as candidates for the putative 5q13.3 tumor suppressor gene involved in the pathogenesis of HCL.

Amino Acid Sequence↗
PubMed1999

Syngeneic transplantation in multiple myeloma - a case-matched comparison with autologous and allogeneic transplantation. European Group for Blood and Marrow Transplantation.

Twenty-five patients with multiple myeloma received bone marrow grafts (n = 24) or peripheral blood stem cells (n = 1) from twin donors. The outcome was compared in a case-matched analysis to 125 patients who underwent autologous transplantation, and 125 who underwent allogeneic transplantation. Seventeen patients (68%) receiving twin transplants entered complete remission, which was not significantly different from that of autologous (48%) or allogeneic (58%) transplants. The median overall and progression-free survival for the twins was 73 and 72 months, respectively. The overall survival tended to be better (73 vs 44 months) and the progression-free survival was significantly better (72 vs 25 months) than with autologous transplantation and both were significantly better than with allogeneic transplantation. Three of 17 patients who entered complete remission following transplantation had relapsed at follow-up. This relapse rate was significantly lower than following autologous transplantation and similar to the relapse rate with allogeneic transplantation. Only two twins died of transplant-related toxicity. Six further patients died of progressive or relapsing disease. Syngeneic transplantation in multiple myeloma appears to be the treatment of choice if a twin donor is available. A lower relapse risk than in autotransplantation may be due to reinfusion of malignant cells in some patients treated with this modality or to the presence of a graft-versus-myeloma effect in some syngeneic transplants.

Adult↗
PubMed1999

Allogeneic bone marrow transplantation in multiple myeloma.

Allogeneic transplantation in multiple myeloma can induce complete remission, defined as disappearance of abnormal immunoglobulins in the blood, light chains in the urine and no apparent myeloma cells in the marrow, in about 50 percent of patients. The five-year survival is about 30 percent and important prognostic factors for survival are to be a female, to be in stage I at the time of diagnosis irrespective of the time of transplantation, to have received only one line of treatment before transplantation, to have responsive disease and a low beta 2-microglobulin. Transplant-related mortality is between 40-50 percent, and therefore overall survival is poorer than with autologous transplantation, while long-term survival is similar with both transplant modalities. Although the relapse rate of patients in complete remission is about 50 percent at 5 years, it is still lower than with autologous transplantation. Donor lymphocyte transfusion to patients with persistent abnormal immunoglobulins or relapse may induce regression or new complete remissions. Further studies aim at reducing transplant-related mortality by using peripheral blood stem cells, CD34-selected cells, more aggressive anti-bacterial, anti-fungal and anti-viral treatment and relapse rate will be counteracted by donor lymphocyte transfusions and perhaps post-transplant interferon treatment.

Bone Marrow Transplantation↗
PubMed1998

Risk assessment for patients with chronic myeloid leukaemia before allogeneic blood or marrow transplantation. Chronic Leukemia Working Party of the European Group for Blood and Marrow Transplantation.

BACKGROUND: Transplantation of blood or bone-marrow stem cells is the treatment of choice for selected patients with chronic myeloid leukaemia (CML). Transplantation is used with increasing frequency and success, but remains associated with substantial risks of morbidity and mortality. Other treatments with satisfactory short-term outcome are available. For appropriate counselling of patients, a rapid and simple way to assess risk is needed. METHODS: Data from 3142 patients (1873 [60%] male, 1269 [40%] female; mean age 34 years, range <1-60 years) treated with allogeneic blood or marrow transplants for CML between 1989 and 1997, reported to the European Group for Blood and Marrow Transplantation (EBMT), were used to develop and test a simple risk score based on previously reported major pretransplant risk factors: histocompatibility, stage of disease at time of transplantation, age and sex of donor and recipient, and time from diagnosis to transplantation. We analysed probabilities of survival, leukaemia-free survival, transplant-related mortality, and relapse incidence with respect to these risk factors. FINDINGS: At the time of analysis, 1922 (61%) of the 3142 patients were alive-1567 (65%) of those with HLA-identical sibling donors and 417 (57%) of those with unrelated donors. 1682 (54%) were alive without relapse. 1220 (39%) patients had died, 1013 (83%) of transplant-related causes, 207 (17%) of relapse. 447 (14%) patients had relapsed. The final scoring system was highly predictive for leukaemia-free survival, survival and transplant-related mortality. Survival at 5 years was 72%, 70%, 62%, 48%, 40%, 18%, and 22% for patients with scores 0, 1, 2, 3, 4, 5, and 6, respectively. Risk of transplant-related mortality was 20%, 23%, 31%, 46%, 51%, 71%, and 73%. Data showed the same trends for HLA-identical sibling transplants and unrelated transplants for transplants done in 1989-93 and 1994-96. INTERPRETATION: Pretransplant risk factors are cumulative for individual patients with CML having blood or marrow transplantation. A simple system based on five main factors gives adequate risk assessment for counselling of patients and taking decisions.

Adolescent↗
PubMed1998

6q deletions in acute lymphoblastic leukemia and non-Hodgkin's lymphomas.

Deletions on the long arm of chromosome 6 are frequently found in acute lymphoblastic leukemia (ALL) and non-Hodgkin's lymphomas (NHL). We have used polymerase chain reaction analysis to study loss of heterozygosity of 16 microsatellite markers on chromosome 6 in 74 ALL and 54 NHL patients. Our results show that deletions of 6q in ALL are more frequent than what has been reported in previous studies, occurring in at least 32% of the patients. The corresponding figure for NHL patients is 7%. Our results define a region of minimal deletion in ALL of less than 500 kb between markers D6S1709 and D6S434. The common region of deletion in NHL is located telomeric of this region. Thus, two different tumor suppressor genes on chromosome 6q seem to be relevant for the development of lymphoid malignancies.

Chromosome Deletion↗
PubMed1998

Detailed molecular delineation of 13q14.3 loss in B-cell chronic lymphocytic leukemia.

A region of chromosome 13q14.3, telomeric to the Retinoblastoma gene RB-1 is frequently deleted in patients with B-cell chronic lymphocytic leukemia (B-CLL). A cosmid and P1-derived artificial chromosome (PAC) contig spanning over 600 kb has been constructed, which encompasses this locus. The contig clones have been used to order a number of markers along the minimally deleted region and to localize a series of CpG islands corresponding to possible candidate genes. A novel polymorphic dinucleotide repeat, 6E3.2, present in one of the ordered cosmid clones has been isolated for use in deletion mapping studies of patient DNA. Leukemic samples from 229 CLL patients have been screened for loss of heterozygosity using microsatellite markers and analyzed for hemizygous and homozygous deletions by Southern blot techniques using genomic probes selected from cosmids across the region. Hemizygous deletions were found in 31% of cases with an additional 10% showing homozygous loss. The use of these probes has defined the commonly deleted area to less than 130 kb, centromeric to the locus D13S272.

Chromosomes, Artificial, Yeast↗