No abstract

A 56-year-old male patient had a history of mantle-cell lymphoma, which was treated with polychemotherapy and reduced-intensity conditioning allogeneic haematopoietic stem cell transplantation (ASCT) from his healthy sister with an identical human leucocyte antigen profile. Six years after transplantation, the patient developed asymptomatic eczema-like cutaneous lesions. Histologically the lesions contained a dense superficial lichenoid infiltrate, mainly consisting of CD4+ atypical medium to large lymphocytes showing indented hyperchromatic nuclei. In situ hybridization for Epstein-Barr virus was negative. PCR amplification of the T-cell receptor-gamma chain gene from several lesions revealed a monoclonal rearrangement without clonal variation. Two-colour fluorescence in situ hybridization (X and Y chromosomes) and microsatellite genotyping were used to compare samples from the patient (transplant recipient), his sister (donor) and the skin biopsy sample, which confirmed that the origin of the neoplastic cells was the donor graft. To our knowledge, this is the first case of post-transplant primary cutaneous T-cell lymphoproliferative disorder after ASCT.

Species distribution models have become some of the most important tools for assessment of impact of climatic change, impact of human activity and for the detection of failure in silvicultural or conservation management plans. In this study, we modeled the potential distribution of 13 tree species of temperate forests distributed in the Mexican state Durango in the Sierra Madre Occidental, for three periods of time. Models were constructed for each period of time using 19 climate variables from the MaxEnt (Maximum Entropy algorithm) modelling algorithm. Those constructed for the future used a severe climate change scenario. When comparing the potential areas of the periods, some species such as Pinus durangensis (Martínez), Pinus teocote (Schiede ex Schltdl. & Cham.) and Quercus crassifolia (Bonpl.) showed no drastic changes. Rather, the models projected a slight reduction, displacement or fragmentation in the potential area of Pinus arizonica (Engelm.), P. cembroides (Zucc), P. engelmanni (Carr), P. leiophylla (Schl), Quercus arizonica (Sarg), Q. magnolifolia (Née) and Q. sideroxila (Humb. & Bonpl.) in the future period. Thus, establishing conservation and reforestation strategies in the medium and long term could guarantee a wide distribution of these species in the future.

Abstract:In defining the environmental preferences of plant species, statistical models are part of the essential tools in the field of modern ecology. However, conventional linear models require compliance with some parametric assumptions and if these requirements are not met, imply a serious limitation of the applied model. In this study, the effectiveness of linear and nonlinear generalized models was examined to identify the unitary effect of the principal environmental variables on the abundance of three tree species growing in the natural temperate forests of Oaxaca, Mexico. The covariates that showed a significant effect on the distribution of tree species were the maximum and minimum temperatures and the precipitation during specific periods. Results suggest that the generalized models, particularly smoothed models, were able to detect the increase or decrease of the abundance against changes in an environmental variable; they also revealed the inflection of the regression. In addition, these models allow partial characterization of the realized niche of a given species according to some specific variables, regardless of the type of relationship.