RESUMO
We evaluated the genotypic origin of mesenchymal stem cells (MSC) following sex-mismatched allogeneic bone marrow transplantation (BMT), and investigated the telomere dynamics in MSC in normal individuals and patients after BMT. The study population consisted of 11 patients with hematologic disorders who showed complete chimerism after BMT. Telomere length was measured in MSC using Southern blotting analysis in eight patients and 18 healthy subjects as a control group. Following culture, MSC were identified by the expression of SH2 and SH4, and lack of CD14, CD34, and CD45. All MSC showed the recipient genotype, based on the results of fluorescent in situ hybridization analysis using X-chromosome satellite probes or microsatellite DNA polymorphism analysis. The mean telomere length in MSC from normal controls was 7.2+/-0.53 kb (range, 6.12-7.78), and progressive telomere shortening was seen with age. There was no significant difference in MSC telomere length between the BMT group and age-matched controls. This study confirmed that the MSC isolated from the recipients of allogeneic BMT did not have the donor genotype, despite complete chimerism. Moreover, MSC were demonstrated to show progressive loss of telomere length with age, but the telomeres in MSC were not affected by BMT.
Assuntos
Transplante de Medula Óssea , Células Estromais/citologia , Telômero/metabolismo , Quimeras de Transplante , Adolescente , Adulto , Células da Medula Óssea , Estudos de Casos e Controles , Células Cultivadas , Criança , Feminino , Genótipo , Doenças Hematológicas/terapia , Humanos , Masculino , Células-Tronco Mesenquimais/citologia , Transplante HomólogoRESUMO
Site-specific recombination by phages lambda and P22 is carried out by multiprotein-DNA complexes. Integration host factor (IHF) facilitates lambda site-specific recombination by inducing DNA bends necessary to form an active recombinogenic complex. Mutants lacking IHF are over 1,000-fold less proficient in supporting lambda site-specific recombination than wild-type cells. Although the attP region of P22 contains strong IHF binding sites, in vivo measurements of integration and excision frequencies showed that infecting P22 phages can perform site-specific recombination to its maximum efficiency in the absence of IHF. In addition, a plasmid integration assay showed that integrative recombination occurs equally well in wild-type and ihfA mutant cells. P22 integrative recombination is also efficient in Escherichia coli in the absence of functional IHF. These results suggest that nucleoprotein structures proficient for recombination can form in the absence of IHF or that another factor(s) can substitute for IHF in the formation of complexes.
Assuntos
Sítios de Ligação Microbiológicos , Proteínas de Bactérias/metabolismo , Bacteriófago P22/genética , Recombinação Genética , Salmonella typhimurium/virologia , Integração Viral/fisiologia , Bacteriófago P22/fisiologia , Escherichia coli/virologia , Fatores Hospedeiros de Integração , Lisogenia , Plasmídeos/genética , Ativação ViralRESUMO
We investigated telomere length changes in patients with non-Hodgkin's lymphoma (NHL) receiving conventional-dose chemotherapy. Using Southern blot analysis, telomere length was measured in peripheral blood mononuclear cells from five NHL patients at diagnosis, 15 NHL patients after chemotherapy, and 39 healthy controls. Compared with age-matched putative normal controls, telomeres were significantly shorter in NHL patients at diagnosis. Mean telomere length was shorter after chemotherapy than before chemotherapy and was shorter after chemotherapy than in age-matched putative healthy controls. There was no correlation between the extent of telomere shortening and time elapsed after chemotherapy. These findings suggest that in NHL patients hematopoietic stem cells lose telomere length during the recovery period from bone marrow suppression after conventional-dose chemotherapy.
Assuntos
Linfoma não Hodgkin/tratamento farmacológico , Linfoma não Hodgkin/genética , Telômero/genética , Protocolos de Quimioterapia Combinada Antineoplásica , Protocolos Antineoplásicos , Southern Blotting , Estudos de Casos e Controles , Ciclofosfamida , Doxorrubicina , Feminino , Humanos , Masculino , Monócitos , Prednisolona , Fatores de Tempo , VincristinaRESUMO
Nitric oxide (NO) is a biological mediator that is synthesized from L-arginine by the nitric oxide synthase (NOS) family. We investigated the expression of iNOS in bone marrow (BM) mononuclear cells (MNCs) using a reverse transcriptase polymerase chain reaction (RT-PCR) assay and the concentration of NO from BM serum by measuring the metabolite NO(2)(-) in 13 patients with aplastic anemia (AA) compared with 10 normal controls who were donors for allogeneic bone marrow transplantation (BMT). All samples of BM MNCs in patients with AA expressed iNOS mRNA, but iNOS was not expressed in patients who were treated successfully with allogeneic BMT. Normal control samples and samples from leukemia patients who had bone marrow aplasia after chemotherapy did not show significant iNOS expression. When we measured the density of bands for both iNOS and beta(2)-microglobin expressed as the iNOS/beta(2)-microglobin density ratio, there was a significant difference in the ratio between AA and normal controls (0.88+/-0.15 vs 0.26+/-0.05, P<0.001). The BM serum NO(2)(-) concentration in the patients with AA was significantly higher than that of normal controls (88.1+/-32.8 microM vs 48.8+/-8.6 microM, P=0.002). In addition, there was a significant correlation between the NO(2)(-) concentration and the calculated iNOS/beta(2)-microglobin density ratio (r=0.567, P=0.01). These findings suggest that upregulation of iNOS expression for local NO production may contribute in part to the pathogenesis of AA.