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Copyright of Medicina (Buenos Aires) is the property of Medicina (Buenos Aires) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Medicina (Buenos Aires) is the property of Medicina (Buenos Aires) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

After a primary immune response, T cell memory occurs when a subset of Ag-speciflc T cells resists peripheral selection by acquiring resistance to TCR-induced death. Recent data have implicated Bcl-2 interacting mediator of death (Bim) as an essential mediator of the contraction phase of T cell immunity. In this article, we describe that stromal-derived factor-l&agr; (SDF-l&agr;) ligation of CXCR4 on activated T cells promotes two parallel processes that favor survival, phospho-inactivation of Foxo3A, as well as Bim extralong isoform (BimEL) degradation, both in an Akt- and Erk-dependent manner. Activated primary CD4 T cells treated with SDF-l&agr; therefore become resistant to the proapoptotic effects of TCR ligation or IL-2 deprivation and accumulate cells of a memory phenotype. Unlike SDF-l&agr;, gp120 ligation of CXCR4 has the opposite effect because it causes p38-dependent BimEL upregulation. However, when activated CD4 T cells are treated with both gpl20 and SDF-l&agr;, the SDF-l&agr;-driven effects of BimEL degradation and acquired resistance to TCR-induced death predominate. These results provide a novel causal link between SDF-l&agr;-induced Chemotaxis, degradation of BimEL, and the development of CD4 T cell memory. [ABSTRACT FROM AUTHOR]

Fluorquinolone-prophylaxis has proven useful in preventing infections in high risk neutropenic patients. The objective of this study was to describe the clinical, microbiological and therapeutic characteristics, and outcome of patients in the first episode of febrile neutropenia, comparing those who received levofloxacin prophylaxis with those who didn't. It was a prospective observational study that included all the episodes of inpatients with febrile neutropenia (February 1997- November 2014), also including the first episode in a same patient in different hospitalizations. Of 946 episodes here included, 821 presented high risk febrile neutropenia. A total of 264 cases (27.9%) received levofloxacin prophylaxis. This group consisted of a higher proportion of high risk febrile neutropenia (99.2% vs. 82.3%, p = 0.0001) and patients that had received an hematopoietic stem cell transplant (67.8% vs. 29.3%, p = 0.0001) compared to those who didn't receive prophylaxis. Those who received levofloxacin prophylaxis presented a similar frequency of clinically diagnosed but a lower proportion of microbiologically documented infections (28.8% vs. 37.5%, p = 0.012) than those who didn't receive prophylaxis. The episodes of bacteremia that occurred in the first group were more frequently caused by multidrug resistant bacteria (MDRB) (34.5% vs. 17.3%, p = 0.007) and by extended spectrum beta lactamase producing Enterobacteriaceae (19% vs. 3.8%, p = 0.0001). The group that received prophylaxis had a lower proportion of adequate empirical antibiotic treatment (69.7% vs. 83.7%, p = 0.009), with similar outcomes in both groups. We suggest that levofloxacin prophylaxis should be stopped whenever there is a rise in the frequency of MDRB infections in this population.

Diarrhea is a frequent and potentially severe complication of kidney transplantation. We describe here, in a cross-sectional study, the epidemiological and microbiological characteristics of acute and persistent diarrhea in 52 inpatients with kidney and kidney-pancreas transplant in a hospital in Buenos Aires, 42 (80.8%) of whom had received a kidney and 10 (19.2%) a kidney-pancreas transplant. Diarrhea was the reason of admission of 34 cases (65.4%). The etiology could be studied in 50 patients: 25 (50%) had no etiological diagnosis of diarrhea and 18 (36%) had a specific infectious etiology: 3 (6%) cytomegalovirus disease, 6 (12%) diarrhea attributed to cytomegalovirus, 5 (10%) to rotavirus and 4 (8%) to Clostridium difficile. In 7 (14%) diarrhea was attributed to drugs (mycophenolate mofetil and sirolimus). Patients with infectious diarrhea had recently received high doses of immunosuppressive therapy more frequently than the rest (p = 0.048). Those with diarrhea attributed to drugs were more frequently on mycophenolate mofetil than the rest (p = 0.039). Empirical modification of the immunosuppressive treatment was done in 16 (30.8%) and empirical antibiotic therapy was given to 47 patients (90.4%). Median length of hospital stay was 6 days. Seven patients (14.6%) persisted with diarrhea at the fifth day of admission. At hospital discharge all cases had complete resolution of symptoms and one third persisted with kidney failure. Information provided in this study can be useful as a starting point for improving preventive, diagnostic and therapeutic measures in these patients.