The endophytic mycobiota of Arabidopsis thaliana

Fungal endophytes are receiving increasing attention as resources to improve crop production and ecosystem management. However, the biology and ecological significance of these symbionts remains poorly understood, due to a lack of model systems for more efficient research. In this work, we have analyzed the culturable endophytic mycobiota associated, in the wild, with leaves and siliques of the model plant A. thaliana. We have studied the effect of biotic and abiotic factors in the frequency of fungal endophytes in plant specimens, and in the species composition of the endophytic community. Our results indicate that the frequency of Arabidopsis plants hosting endophytes depends on the time of the year and the phenological stage of the plant, and that the probability of endophyte colonization increases as the life cycle of the plant progresses. The diversity of the endophytic assemblages of natural A. thaliana populations was high, and precipitation and temperature were the two main factors determining the diversity and species composition of the communities. We propose A. thaliana and its endophytes as a model system for an integral approach to the principles governing the endophytic lifestyle, taking advantage of the molecular tools and the abundant knowledge accessible from the host plant.     

The clinical implications of platelet transfusions associated with ABO or Rh(D) incompatibility

Despite the time elapsed since their development, and substantial human and economical efforts searching for alternatives, platelet transfusion, continues to be the main therapeutic measure available for the management of patients suffering from quantitative and qualitative platelet disorders. However, there are still aspects of their use that are not completely established. One of these is ABO and/or Rh(D) compatibility. A major ABO group incompatibility appears to decrease the response to a platelet transfusion, whereas a minor ABO incompatibility can be associated with, sometimes lethal, acute hemolytic transfusion reactions in the recipient. Other detrimental effects on the recipient of a minor ABO incompatibility have also been reported. In contrast, the main problem associated to a Rh(D) incompatible platelet transfusion is the development of alloimmunization of a Rh(D)-negative woman in childbearing age or younger. Factors like degree of patient immunosuppression and red blood cell content in the platelet concentrate significantly modulate the risk of alloimmunization. New clinical studies are needed to define clearly the current risk associated to ABO- and/or Rh(D)-incompatible platelet transfusions, and such defined risks would help establish the most cost effective measures to prevent the appearance of the potential complications related to platelet use.     

Enlightenment about the new Architect-i2000 estradiol (Abbott Laboratories) immunoassay during in vitro fertilization

OBJECTIVE: We assessed a new estradiol (E2) immunoassay on the Architect-i2000 (Abbott Laboratories) for monitoring ovulation stimulation for IVF-ET and re-establishing clinical cut-off points. The method has been modified to improve E2 measurements especially at normal and low concentrations. DESIGN AND METHOD: E2 was determined for 552 samples, from 83 women, presenting normal follicular status and undergoing 100 cycles of IVF treatment. We assessed the value of this assay for down-regulation of E2 concentration limit using gonadoliberin-releasing hormone agonist (GnRHa), and monitoring of the ovarian hyperstimulation, expected range of E2 per mature follicle prior to the administration of exogenous hCG and day 3 concentration limit. We compared results with our routine method (E2-6II Advia-Centaur; Siemens-Diagnostics) for which decision-making values were known. RESULTS: Considering E2 concentrations obtained with the new Architect-i2000 assay for patients treated with GnRHa for 2 weeks, the cutoff-point for ovarian down-regulation should be set down at 110 pmol/L to maintain 100% of sensitivity. Considering day 3 concentration limit determination, results were not significantly different from those obtained with our routine method. The mean E2 values per mature follicle fell into the range generally expected. CONCLUSION: E2 determination with the new E2 Architect-i2000 assay could be used to monitor ovulation, in patients undergoing IVF-ET, in combination with transvaginal ultrasound.     

Impact of Human Leukocyte Antigen Molecules E,F, and G on the Outcome of Transplantation

BackgroundHLA class I molecules are divided into classic (Ia) and nonclassic (Ib). Nonclassic HLA molecules (E, F, and G) have acquired relevance owing to their immunomodulatory properties and possible repercussions for induction of tolerance in organ transplantation. The objective of this study was to identify the impact of these molecules on transplant success or failure.MethodsA systematic review of literature was performed with the use of MeSH terms in Pubmed. Clinical trials, randomized clinical trials, case-control studies, and reviews from the past 15 years were included.ResultsHLA-E*0103/E*0103 genotype is associated with lower risk of graft-versus-host disease, decreased mortality, and greater disease-free survival after bone marrow transplantation. There were no significant associations between HLA-F and clinical outcomes in any of the studies. Elevated serum levels of HLA-G were associated with a lower incidence of rejection in hepatic and renal transplantation during the 1st year and lower T-cell response after bone marrow, liver, and kidney transplantation. Detection of mRNA of HLA-G1 was also associated with less graft rejection.ConclusionsCurrent literature suggests that nonclassic HLA Ib molecules play an important role in immunotolerance in organ transplantation; however, more studies are required to predict outcomes related to specific genotypes.