68 resultados para Operant conditioning


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We describe a single centre experience of eight consecutive patients with relapsed or refractory Ph+ ALL treated with the FLAG/idarubicin regimen followed by BMT or PBSCT. Following FLAG/idarubicin, one achieved a partial response and seven CR. All patients subsequently received allogeneic transplants: one sibling BMT, three matched unrelated (MUD) BMT and four sibling PBSCT. Two patients received second transplants with PBSC from their original BM donors following FLA/Ida with no further conditioning. Three patients are alive in CR 9, 24 and 32 months after transplant. Seven of eight patients had a cytogenetic response following FLAG/Ida induction and one of seven became bcr-abl negative. All eight patients had a complete cytogenetic response following transplant. Four of five assessable patients became p190 bcr-abl negative after transplant; three of these subsequently relapsed. Both patients with the p210 bcr-abl transcript remained bcr-abl positive in CR after transplant. FLAG/Ida was well tolerated and appears to be effective in inducing remission in relapsed Ph+ ALL. The use of FDR-containing chemotherapy without further conditioning prior to PBSCT deserves further study in heavily pre-treated patients and, in patients with relapsed ALL following BMT, may be a safer option than DLI (donor lymphocyte infusion) by avoiding the associated risk of aplasia.

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Ex vivo T cell depletion of allogeneic grafts is associated with a high (up to 80%) rate of mixed chimerism (MC) posttransplantation. The number of transplanted progenitor cells is an important factor in achieving complete donor chimerism in the T cell depletion setting. Use of granulocyte colony-stimulating factor (G-CSF) peripheral blood allografts allows the administration of large numbers of CD34+ cells. We studied the chimeric status of 13 patients who received allogeneic CD34+-selected peripheral blood progenitor cell transplants (allo-PBPCTs/CD34+) from HLA-identical sibling donors. Patients were conditioned with cyclophosphamide (120 mg/kg) and total-body irradiation (13 Gy in four fractions). Apheresis products were T cell-depleted by the immunoadsorption avidin-biotin method. The median number of CD34+ and CD3+ cells infused was 2.8x10(6)/kg (range 1.9-8.6x10(6)/kg) and 0.4x10(6)/kg (range 0.3-1x10(6)/kg), respectively. Molecular analysis of the engraftment was performed using polymerase chain reaction (PCR) amplification of highly polymorphic short tandem repeat (PCR-STR) sequences in peripheral blood samples. MC was detected in two (15%) of 13 patients. These two patients relapsed at 8 and 10 months after transplant, respectively. The remaining 11 patients showed complete donor chimerism and were in clinical remission after a maximum follow-up period of 24 months (range 6-24 months). These results were compared with those obtained in 10 patients who were treated with T cell-depleted bone marrow transplantation by means of elutriation and who received the same conditioning treatment and similar amounts of CD3+ cells (median 0.45x10(6)/kg; not significant) but a lower number of CD34+ cells (median 0.8x10(6)/kg; p = 0.001). MC was documented in six of 10 patients (60%), which was significantly higher than in the allo-PBPCT/CD34+ group (p = 0.04). We conclude that a high frequency of complete donor chimerism is achieved in patients receiving allo-PBPCT/CD34+ and that this is most likely due to the high number of progenitor cells administered.

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Chronic myeloid leukaemia (CML) can be treated successfully with allogeneic bone marrow transplantation (BMT) leading to long-term disease-free survival. Leukemia relapse, however, remains a significant clinical problem. Relapse following BMT presumably results from the expansion of small numbers of recipient leukaemic cells which have survived the conditioning therapy. In order to define patients who are at a high risk of leukaemia relapse, a variety of techniques have been employed to detect persistence of host haemopoiesis (mixed chimaerism, MC) or residual leukaemia (minimal residual disease, MRD). However, the precise relationship between the detection of MC and MRD post-BMT is unknown. We have investigated chimaerism and MRD status in 22 patients who were in clinical and haematological remission post-allogeneic BMT for chronic phase CML. Chimaerism was assessed using short tandem repeat PCR (STR-PCR) while BCR-ABL mRNA detection using reverse transcriptase polymerase chain reaction (RT-PCR) was performed to detect the presence of MRD. Seventeen patients received unmanipulated marrow (non-TCD) while in five patients a T cell-depleted transplant (TCD) was performed as additional GVHD prophylaxis. Chimaerism was evaluated in 18 patients (14 non-TCD, four TCD). Mixed chimaerism was an uncommon finding in recipients of unmanipulated BMT (21%) when compared to TCD BMT (100%). No evidence of MRD, as identified using the BCR-ABL mRNA RT-PCR assay, was detected in those patients who were donor chimaeras. Early and transient MC and MRD was detected in four patients (two non-TCD, two TCD) who have subsequently converted to a donor profile. One patient has stable low-level MC but remains MRD negative 4 years post-BMT. Late MC and MRD was observed in two patients who relapsed >6 years after TCD BMT for CML. We conclude that mixed chimaerism is a rare event in recipients of unmanipulated BMT and that donor chimaerism as detected by STR-PCR assay is consistent with disease-free survival and identifies patients with a low risk of leukaemic relapse post-BMT for CML.

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It is important to be able to assess the contribution of donor cells to the graft followmg bone marrow transplantation (BMT), as complete engraftment of marrow progenitors that can give rise to long term donor derived hemopoiesis may be important in long-term disease-free survival. The contribution of the donor marrow, both in terms of filling the marrow "space" created by the intense conditioning regimen and in its ability to mediate a graft versus leukemia effect may be assessed by studying the kinetics of the engraftment process. As BMT involves repopulation of the host hemopoietic system with donor cells, recipients of allogeneic marrow are referred to as hemopoietic chimeras. A donor chimera is an individual who exhibits complete donor hemopoiesis and we would imagine that donor chimertsm carries the best long-term prognosis. A patient who has both donor and recipient cells coexistmg in a stable fashion post-BMT without hematological evidence of relapse or graft rejection is referred to as a mixed chimera. Mixed chimerism may be a prelude to graft rejection or leukemic relapse; therefore, it is important to be able to monitor the presence of these cells in a precise manner.

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Autologous stem cell transplantation (ASCT) consolidation remains the treatment of choice for patients with relapsed diffuse large B cell lymphoma. The impact of rituximab combined with chemotherapy in either first- or second-line therapy on the ultimate results of ASCT remains to be determined, however. This study was designed to evaluate the benefit of ASCT in patients achieving a second complete remission after salvage chemotherapy by retrospectively comparing the disease-free survival (DFS) after ASCT for each patient with the duration of the first complete remission (CR1). Between 1990 and 2005, a total of 470 patients who had undergone ASCT and reported to the European Blood and Bone Transplantation Registry with Medical Essential Data Form B information were evaluated. Of these 470 patients, 351 (74%) had not received rituximab before ASCT, and 119 (25%) had received rituximab before ASCT. The median duration of CR1 was 11 months. The median time from diagnosis to ASCT was 24 months. The BEAM protocol was the most frequently used conditioning regimen (67%). After ASCT, the 5-year overall survival was 63% (95% confidence interval, 58%-67%) and 5-year DFS was 48% (95% confidence interval, 43%-53%) for the entire patient population. Statistical analysis showed a significant increase in DFS after ASCT compared with duration of CR1 (median, 51 months versus 11 months; P < .001). This difference was also highly significant for patients with previous exposure to rituximab (median, 10 months versus not reached; P < .001) and for patients who had experienced relapse before 1 year (median, 6 months versus 47 months; P < .001). Our data indicate that ASCT can significantly increase DFS compared with the duration of CR1 in relapsed diffuse large B cell lymphoma and can alter the disease course even in patients with high-risk disease previously treated with rituximab.

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Bone Mineral Density (BMD) is a highly heritable trait, but genome-wide association studies have identified few genetic risk factors. Epidemiological studies suggest associations between BMD and several traits and diseases, but the nature of the suggestive comorbidity is still unknown. We used a novel genetic pleiotropy-informed conditional False Discovery Rate (FDR) method to identify single nucleotide polymorphisms (SNPs) associated with BMD by leveraging cardiovascular disease (CVD) associated disorders and metabolic traits. By conditioning on SNPs associated with the CVD-related phenotypes, type 1 diabetes, type 2 diabetes, systolic blood pressure, diastolic blood pressure, high density lipoprotein, low density lipoprotein, triglycerides and waist hip ratio, we identified 65 novel independent BMD loci (26 with femoral neck BMD and 47 with lumbar spine BMD) at conditional FDR < 0.01. Many of the loci were confirmed in genetic expression studies. Genes validated at the mRNA levels were characteristic for the osteoblast/osteocyte lineage, Wnt signaling pathway and bone metabolism. The results provide new insight into genetic mechanisms of variability in BMD, and a better understanding of the genetic underpinnings of clinical comorbidity.

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This study follows on from a research project that developed guidelines for the Universal Design (UD) of Dementia Friendly Dwellings for People with Dementia, their Families and Carers. Research findings point to the need for thermal environments that support people with dementia and do not provoke stress, agitation or anxiety. Using semi-structured interviews and qualitative analysis of people with dementia this paper aims to provide insight into the questions of appropriate thermal environments. The qualitative analysis is supported by example simulated indoor environment studies that investigate comfort in common thermal environment provision scenarios in the homes of people with dementia. This paper focuses on the thermal environment, its impact on people with dementia, its therapeutic value, and its role in encouraging engagement in every day activity.
Findings from the interviews emphasize that control over their own internal environment is a priority for people with dementia. A strong preference for naturally or passively conditioned environments over mechanical conditioning is evident. Preferences are expressed for naturally ventilated environments enabling occupant instigated air movement. Repeated emphasis is placed on familiar elements including the fire and hot water bottle. Little desire is expressed for information feedback or technological displays.

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Willingness to lay down one’s life for a group of non-kin, well documented in the
historical and ethnographic records, represents an evolutionary puzzle. Here we
present a novel explanation for the willingness to fight and die for a group, combining evolutionary theorizing with empirical evidence from real-world human groups. Building on research in social psychology, we develop a mathematical model showing how conditioning cooperation on previous shared experience can allow extreme (i.e., life-threatening) pro-social behavior to evolve. The model generates a series of predictions that we then test empirically in a range of special sample populations (including military veterans, college fraternity/sorority members, football fans, martial arts practitioners, and twins). Our results show that sharing painful experiences produces “identity fusion” – a visceral sense of oneness – more so even than bonds of kinship, in turn motivating extreme pro-group behavior, including willingness to fight and die for the group. These findings have theoretical and practical relevance. Theoretically, our results speak to the origins of human cooperation, as we offer an explanation of extremely costly actions left unexplained by existing models.
Practically, our account of how shared dysphoric experiences produce identity fusion, which produces a willingness to fight and die for a non-kin group, helps us better understand such pressing social issues as suicide terrorism, holy wars, sectarian violence, gang-related violence, and other forms of intergroup conflict.