Pre-existing autoimmune disease in patients with long-term survival after allogeneic bone marrow transplantation.

We reviewed the experience with allogeneic bone marrow transplantation (BMT) at Fred Hutchinson Cancer Research Center and affiliated Seattle hospitals for patients with preexisting autoimmune diseases. The review was limited to patients who received transplants between 1969 and 1989 from a related donor and who had at least 3 years of relapse-free survival. Of 901 evaluable patients, 11 were identified with a preexisting autoimmune disease and 2 with diseases that were possibly autoimmune in nature. Pretransplant diseases identified in this review included rheumatoid arthritis (n = 1), discoid or systemic lupus (n = 2), insulin dependent Type 1 diabetes (n = 3), hyperthyroidism (n = 4), dermatitis herpetiformis (n = 1), vasculitis (n = 1), and Crohn's disease (n = 1). All 13 patients survive with a median followup of 14 (range, 7-20) years after transplantation from an HLA identical sibling (n = 10), parent (n = 1) or identical twin (n = 2). Pre and post-transplant histories are presented. Variables to be considered in the assessment of any beneficial effect of BMT are discussed, including consideration of different patterns of activity that describe the natural history of various autoimmune diseases. Although autoimmune disease did not recur after allogeneic BMT in these 13 patients, disease and post-transplant variables may confound the interpretation of results from retrospective analysis.

Deteccion de casos autoctonos de malaria urbana por P. vivax en Barrios el Plan 3000, Santa Cruz-Bolivia / Detection of autocthonous cases of urban malaria by P. vivax in districts of the Plan 3000, Santa Cruz-Bolivia

Por medio de una encuesta epidemiologica realizada a 61 pacientes con diagnostico confirmado de infeccion por P.vivax en el "Plan 3000", una zona peri-urbana de la ciudad de Santa Cruz, se observo que 9 (15 por ciento) de los casos se presentaron en niños menores de 5 años y que 44 (72 por ciento) reportaron no haber tenido antecedente paludico, no haber vivido en los ultimos 5 años en zonas endemicas, ni haber visitado estas hasta 30 dias antes de la aparicion del cuadro febril lo que hace improbable una recaida por hipnozoito o malaria importada. Ademas, el numero de casos de malaria se concentro en los barrios donde las condiciones ecologicas para la reproduccion del vector son mas favorables tal como fue verificado con capturas larvarias del vector anofeles pseudopunctipennis. todas estas observaciones nos permiten indicar que efectivamente existe transmision local de P.vivax en la ciudad de Santa Cruz y que son necesarios estudios posteriores para cuantificar la magnitud del problema y caracterizarlo con vista de tomar eficientes medidas de control

Resource islands predict the distribution of heterotrophic bacteria in chihuahuan desert soils.

The resource island hypothesis predicts that soil resources such as nitrogen, phosphorus, and water will be distributed evenly in grasslands but have a patchy distribution focused around plants in shrublands. This hypothesis predicts that microorganism numbers will follow resources and be (i) evenly distributed in grasslands, (ii) concentrated around individual plants in shrublands, and (iii) higher where resources are higher when comparing the same vegetation type. This study enumerated total heterotrophic bacteria and a subset of these, the nitrogen-efficient guild (NEG), in three shrublands (playa fringe mesquite, tar bush, and creosote) and two grasslands (playa and bajada). Both heterotrophs and NEG members followed the distribution pattern predicted by the resource island hypothesis. There were no significant differences in heterotroph or NEG numbers comparing at-plant and interplant samples for both the playa and bajada grasslands. Furthermore, populations were generally higher in nutrient-rich playa grasslands than nutrient-poor bajada grasslands. In contrast, both heterotroph and NEG numbers were higher at shrubs than between shrubs in all three shrub sites. These results suggest that resource abundance in resource islands predicts the distribution of heterotrophic bacterial numbers in desert soils.

Seasonal and spatial population dynamics of the nitrogen-efficient guild in a desert bajada grassland.

This study examined the temporal and spatial variation in the populations of bacteria from a Chihuahuan desert bajada grassland that could grow on nearly nitrogen-free medium, a nitrogen-efficient guild (NEG). A Curtis similarity index of 0.876 and nearly identical diversity and equability indexes (H' = 1.22, J = 0.46 and H' = 1.27, J = 0.48 for the crown edge and interplant samples, respectively) indicated that there was no qualitative difference between the NEG assemblages isolated from samples taken at Bouteloua eriopoda plant crowns and in nonvegetated areas 45 cm from crowns. The difference in NEG populations between the crown and interplant samples was only 2-fold, despite a 9.5-fold difference in root biomass between the sites. These differences, while consistent, were statistically significant at only 50% of the sampling times. There was over an order of magnitude difference in NEG numbers in root-associated soil and in bulk soil from the crown or intercrown sites. The typical trend for temporal variation in NEG numbers was that they increased in the spring, fluctuated dramatically over the summer, and declined at the summer's end. The pattern of soil moisture change was the only abiotic variable which showed the same fluctuation pattern as NEG numbers.

Effect of water and nitrogen additions on free-living nitrogen fixer populations in desert grass root zones.

In this study we measured changes in population levels of free-living N2-fixing bacteria in the root zones of potted Bouteloua eriopoda and Sporobolus flexuosus plants as well as the photosynthetic indices of the plants in response to added nitrogen, added water, and added water plus nitrogen treatments. In addition, N2 fixer population changes in response to added carbon source and nitrogen were measured in plant-free soil columns. There were significant increases in the numbers of N2 fixers associated with both plant species in the water and the water plus nitrogen treatments. Both treatments increased the photosynthetic index, suggesting that plant exudates were driving N2 fixer population changes. Population increases were greatest in the water plus nitrogen treatments, indicating that added nitrogen was synergistic with added water and suggesting that nitrogen addition spared bacteria the metabolic cost of N2 fixation, allowing greater reproduction. Plant-free column studies demonstrated a synergistic carbon-nitrogen effect when carbon levels were limiting (low malate addition) but not when carbon was abundant (high malate), further supporting this hypothesis. The results of this study indicate the presence of N2 fixer populations which interact with plants and which may play a role in the nitrogen balance of desert grasslands.