Tephra transformations: variable preservation of tephra layers from two well-studied eruptions

Financial support was provided by the National Science Foundation of America through grant 1202692 ‘Comparative Island Ecodynamics in the North Atlantic’, and grant 1249313 ‘Tephra layers and early warning signals for critical transitions’ (both to AJD).Volcanologists often use terrestrial tephra layers to reconstruct volcanic eruptions. However, the conversion of fresh tephra deposits into tephra layers is poorly understood. To address this knowledge gap, we surveyed tephra layers emplaced by the 1980 eruption of Mount St Helens, USA (MSH1980) and the 1947 eruption of Hekla, Iceland (H1947). We compared our measurements with observations made shortly after the 1947 and 1980 eruptions, to calibrate the subsequent transformation of the tephra deposit. We expected the tephra layers to retain the broad characteristics of the original deposits, but hypothesized a) changes in thickness and mass loading due to re-working, and b) positive correlations between thickness and vegetation density. We observed some systematic changes in tephra layer properties with distance from the vent and the main plume axis. However, the preservation of the layers varied both between and within our survey locations. Closed coniferous forest appeared to provide good conditions for the preservation of the MSH1980 tephra, as expected; preservation of the H1947 deposit in sparsely vegetated parts of Iceland was much more variable. However, preservation of the MSH1980 deposit in sparsely vegetated areas of eastern Washington State was also excellent, possibly due to biocrust formation. We concluded that the preservation of tephra layers is sensitive to surface conditions at the time of the eruption. These findings have implications for the reconstruction of past eruptions where eruption plumes span regions of variable surface cover.PostprintPeer reviewe

A Prognostic Score for Patients with Acute Leukemia or Myelodysplastic Syndromes Undergoing Allogeneic Stem Cell Transplantation

AbstractAllogeneic hematopoietic stem cell transplantation (SCT) has the potential to cure patients with acute leukemia or myelodysplastic syndromes (MDS), but a number of prognostic factors can influence the outcome of transplantation. At present, no transplantation-specific risk score exists for this patient population. We propose a simple scoring system for patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL), or MDS, based on a retrospective analysis of 445 patients undergoing SCT at our institution (divided into training and validation subsets). The score depends on 5 variables: age, disease, stage at transplantation, cytogenetics, and pretransplantation ferritin. It divides patients into 3 groups of comparable size, with 5-year overall survival (OS) of 56% (low risk), 22% (intermediate risk), and 5% (high risk). This prognostic score could be useful in making treatment decisions for individual patients, in stratifying patients entering clinical trials, and in adjusting transplantation outcomes across centers under the new federal reporting rules

dynamics of immune cell reconstitution in allogeneic hematopoietic cell transplant patients receiving post transplant cyclophosphamide ptcy

In the setting of haploidentical hematopoietic cell transplantation (haplo-HCT), post-transplant cyclophosphamide (PTCy) selectively eliminates alloreactive T cells in-vivo, resulting in favorable graft versus host disease (GVHD), non-relapse mortality (NRM) and relapse outcomes. However, few studies have examined the impact of PTCy on immune reconstitution (IR). We quantified IR in 63 patients after haplo-HCT with PTCy, mofetil mycophenolate and tacrolimus (TAC) and compared results to 93 patients with 8/8 HLA matched related or unrelated donors (MD) receiving TAC, methotrexate and sirolimus for GVHD prophylaxis. Both groups received reduced intensity conditioning for hematologic malignancies. The median age of the Haplo-PTCy and MD cohorts was 55 and 57 years. Patient samples were analyzed using multi-color flow cytometry panels to characterize distinct lymphocyte populations. All IR values are expressed as median absolute cell count per μL. One month after HCT, recovery of all T cell subsets (CD3, CD4Tcon, Treg, CD8) was significantly reduced in the PTCy cohort compared to MD (Figure A, B, C). Recovery of CD4Tcon was also reduced at 2 and 3 months after PTCy (p NK cells were lower 1 month after PTCy (52.7 vs 91.1, p=0.08), but were significantly higher at 2, 3 and 6 months (153.4 vs 94.8, p=0.001, 153.7 vs 87.5, p=0.008, 180 vs 102, p=0.01, respectively, Figure D) compared to the MD cohort. Delayed NK cell recovery at 1 month after PTCy was due entirely to reduced numbers of CD56dim NK cells (Figure E). Subsequently recovery of CD56dim NK cells was similar in both cohorts. Recovery of CD56bright NK cells was significantly increased in the PTCy cohort (p Consistent with prior reports, 1 year cumulative incidence of extensive cGvHD was lower in the PTCy cohort compared to the MD cohort, 13% (5-26%, 95% CI) and 40% (30-50%, 95% CI) respectively, p=0.003, without increased NRM (p=0.28) or relapse (p=0.17). In summary, the effect of PTCy on IR was most pronounced 1 month after transplant with significantly delayed recovery of CD3, CD4Tcon, Treg, CD8 and CD56dim NK cells. Slow recovery of CD4Tcon persisted for 3 months and delayed recovery of Treg persisted for 1 year. Beginning 2 months after HCT, recovery of both CD56dim and CD56bright NK cells was more rapid in the PTCy cohort. Further studies will examine the effects of these differences in IR on clinical outcomes such as relapse, infections and GVHD

Mucositis after Allogeneic Hematopoietic Stem Cell Transplantation: A Cohort Study of Methotrexate- and Non-Methotrexate-Containing Graft-versus-Host Disease Prophylaxis Regimens

AbstractOral mucositis occurs in up to 75% of recipients of high-dose chemoradiotherapy conditioning regimens used for allogeneic hematopoietic stem cell transplantation (HSCT). As a result of mucositis, narcotic analgesia and total parenteral nutrition (TPN) are commonly required after HSCT. Methotrexate, an antiproliferative graft-versus-host disease (GVHD) prophylaxis agent, impairs mucosal regeneration and worsens and prolongs mucositis. We assessed the effect of substituting sirolimus for methotrexate as GVHD prophylaxis on outcomes associated with mucositis. Two patient cohorts undergoing allogeneic HLA-matched related donor peripheral blood stem cell transplantation with cyclophosphamide/total body irradiation conditioning were prospectively analyzed for mucositis severity and retrospectively reviewed for correlative outcomes. GVHD prophylaxis consisted of sirolimus/tacrolimus (ST) in the study group and tacrolimus/methotrexate (TM) in the control group. Thirty patients received ST and 24 patients received TM as GVHD prophylaxis between October 2000 and May 2003. Mild, moderate, and severe mucositis was noted in 37%, 57%, and 7% of the ST group and 8%, 42%, and 50% of the TM group (P = .0002). Less TPN was used in the ST group than the TM group (17% versus 43% of posttransplantation hospital days; P = .02). The total number of narcotic days was lower in the ST group in comparison with the TM group (median, 13.5 versus 17 days; P = .08). The time to first hospital discharge was shorter in the ST group compared with the TM group (median, 18 versus 22 days; P = .07). The substitution of sirolimus for methotrexate as GVHD prophylaxis is associated with a reduction in mucositis severity. As a result, TPN and narcotic use are reduced, and hospitalization duration is shortened. Less toxic GVHD prophylaxis regimens without methotrexate may have a significant effect on patient quality of life, patient outcomes, and economic outcomes associated with allogeneic stem cell transplantation

Long-Term Follow-up of Reduced Intensity Allogeneic Stem Cell Transplantation for Chronic Lymphocytic Leukemia: Prognostic Model to Predict Outcome

CLL remains incurable with chemoimmunotherapy, and allogeneic hematopoietic stem cell transplantation (HSCT) offers potential for cure. We assessed the outcomes of 108 CLL patients undergoing first allogeneic HSCTs, 76 with reduced intensity (RIC) and 32 with myeloablative (MAC) conditioning between 1998 and 2009 at Dana-Farber Cancer Institute. With median follow-up 5.9 years in surviving patients, the 5 year OS for the entire cohort is 63% for RIC regimens and 49% for MAC regimens (p=0.18). The risk of death declined significantly starting in 2004 and we found that 5 year OS for HSCT between 2004–2009 was 83% for RIC regimens compared to 47% for MAC regimens (p=0.003). For RIC transplantation, we developed a prognostic model based on predictors of PFS, specifically remission status, LDH, comorbidity score and lymphocyte count, and found 5-year PFS 83% for score 0, 63% for score 1, 24% for score 2, and 6% for score >= 3 (p<0.0001). We conclude that RIC HSCT for CLL in the current era is associated with excellent long-term PFS and OS, and, as potentially curative therapy, should be considered early in the disease course of relapsed high-risk CLL patients

A Bortezomib-Based Regimen Offers Promising Survival and Graft-versus-Host Disease Prophylaxis in Myeloablative HLA-Mismatched and Unrelated Donor Transplantation: A Phase II Trial

AbstractHematopoietic stem cell transplantation (HSCT) recipients lacking HLA-matched related donors have increased graft-versus-host disease (GVHD) and nonrelapse mortality (NRM). Bortezomib added to reduced-intensity conditioning can offer benefit in T cell–replete HLA-mismatched HSCT and may also benefit myeloablative conditioning (MAC) transplants. We conducted a phase II trial of short-course bortezomib plus standard tacrolimus/methotrexate after busulfan/fludarabine MAC in 34 patients with predominantly myeloid malignancies. Fourteen (41%) received 8/8 HLA-matched unrelated donor (MUD) and 20 (59%) received 7/8 HLA-mismatched related/unrelated donor peripheral blood stem cell grafts. Median age was 49 years (range, 21 to 60), and median follow-up was 25 months (range, 11 to 36). The regimen was well tolerated. No dose modifications were required. Neutrophil and platelet engraftment occurred at a median of 14 (range, 10 to 33) and 17 (range, 10 to 54) days, respectively. Median 30-day donor chimerism was 99% (range, 90 to 100), and 100-day grades II to IV and III to IV acute GVHD incidence was 32% and 12% respectively. One-year chronic GVHD incidence was 50%. Two-year cumulative incidence of both NRM and relapse was 16%. Two-year progression-free and overall survival rates were 70% and 71%, respectively. Outcomes were comparable to an 8/8 MUD MAC cohort (n = 45). Immune reconstitution was robust. Bortezomib-based MAC HSCT is well tolerated, with HLA-mismatched outcomes comparable with 8/8 MUD MAC HSCT, and is suitable for randomized evaluation. (clinicaltrials.gov: NCT01323920.

Allogeneic Hematopoietic Cell Transplantation Improves Outcome in Myelodysplastic Syndrome Across High-Risk Genetic Subgroups:Genetic Analysis of the Blood and Marrow Transplant Clinical Trials Network 1102 Study

PURPOSE:Allogeneic hematopoietic cell transplantation (HCT) in patients with myelodysplastic syndrome (MDS) improves overall survival (OS). We evaluated the impact of MDS genetics on the benefit of HCT in a biological assignment (donor v no donor) study.METHODS:We performed targeted sequencing in 309 patients age 50-75 years with International Prognostic Scoring System (IPSS) intermediate-2 or high-risk MDS, enrolled in the Blood and Marrow Transplant Clinical Trials Network 1102 study and assessed the association of gene mutations with OS. Patients with TP53 mutations were classified as TP53multihit if two alleles were altered (via point mutation, deletion, or copy-neutral loss of heterozygosity).RESULTS:The distribution of gene mutations was similar in the donor and no donor arms, with TP53 (28% v 29%; P =.89), ASXL1 (23% v 29%; P =.37), and SRSF2 (16% v 16%; P =.99) being most common. OS in patients with a TP53 mutation was worse compared with patients without TP53 mutation (21% ± 5% [SE] v 52% ± 4% at 3 years; P &lt;.001). Among those with a TP53 mutation, OS was similar between TP53single versus TP53multihit (22% ± 8% v 20% ± 6% at 3 years; P =.31). Considering HCT as a time-dependent covariate, patients with a TP53 mutation who underwent HCT had improved OS compared with non-HCT treatment (OS at 3 years: 23% ± 7% v 11% ± 7%; P =.04), associated with a hazard ratio of 3.89; 95% CI, 1.87 to 8.12; P &lt;.001 after adjustment for covariates. OS among patients with molecular IPSS (IPSS-M) very high risk without a TP53 mutation was significantly improved if they had a donor (68% ± 10% v 0% ± 12% at 3 years; P =.001).CONCLUSION:HCT improved OS compared with non-HCT treatment in patients with TP53 mutations irrespective of TP53 allelic status. Patients with IPSS-M very high risk without a TP53 mutation had favorable outcomes when a donor was available.</p

Beneficial effects of word final stress in segmenting a new language: evidence from ERPs

Background: How do listeners manage to recognize words in an unfamiliar language? The physical continuity of the signal, in which real silent pauses between words are lacking, makes it a difficult task. However, there are multiple cues that can be exploited to localize word boundaries and to segment the acoustic signal. In the present study, word-stress was manipulated with statistical information and placed in different syllables within trisyllabic nonsense words to explore the result of the combination of the cues in an online word segmentation task. Results: The behavioral results showed that words were segmented better when stress was placed on the final syllables than when it was placed on the middle or first syllable. The electrophysiological results showed an increase in the amplitude of the P2 component, which seemed to be sensitive to word-stress and its location within words. Conclusion: The results demonstrated that listeners can integrate specific prosodic and distributional cues when segmenting speech. An ERP component related to word-stress cues was identified: stressed syllables elicited larger amplitudes in the P2 component than unstressed ones