Search

Background: Protein Fv is an endogenous protein, synthesized in liver and largely released in the digestive tract during acute and chronic viral hepatitis, that binds to immunoglobulin (Ig) from various mammalian and nonmammalian species. Methods: Basophils obtained from normal subjects were purified by a double Percoll gradient and elutriation. The secretion of histamine induced by protein Fv was assayed by a fluorometric technique, the extracellular protein levels of IL–4 and IL–13 were measured by ELISA, and IL–4 mRNA levels were evaluated by RT–PCR. Results: Protein Fv concentration–dependently induced histamine and IL–4 and IL–13 release from purified basophils. IL–4 mRNA, constitutively present in basophils, was increased after stimulation by protein Fv. Histamine and IL–4 secretion from basophils, but not histamine and IL–13 release, activated by protein Fv was significantly correlated (r[sub s ] = 0.70, p<0.001). Basophils from which IgE had been dissociated by brief exposure to lactic acid no longer released IL–4 in response to protein Fv and anti–IgE. Two preparations of human V[sub H] 3[sup +] monoclonal IgM inhibited protein Fv–induced secretion of IL–4 and histamine from basophils. In contrast, V[sub H] 6[sup +] monoclonal IgM did not inhibit the release of mediators caused by protein Fv. Conclusions: These results indicate that protein Fv, which acts as an endogenous superallergen, interacts with the V[sub H] 3 domain of IgE to induce the synthesis and release of IL–4, IL–13 and the secretion of histamine from basophils. [ABSTRACT FROM AUTHOR]

Objective: To propose a standardized protocol for the evaluation of Legionella contamination in air., Design: A bathroom having a Legionella contamination in water >1,000 cfu/l was selected in 10 different healthcare facilities. Air contamination was assessed by active (Surface Air System, SAS) and passive (Index of Microbial Air, IMA) sampling for 8 hours, about 1 m away from the floor and 50 cm from the tap water. Two hundred liters of air were sampled by SAS every 12 min, after flushing water for 2 min. The IMA value was calculated as the mean value of colony forming units/16 plates exposed during sampling (2 plates/hour). Water contamination was evaluated at T0, after 4 and 8 hours, according to the standard methods., Results: Air contamination by Legionella was found in three healthcare facilities (one with active and two with passive sampling), showing a concomitant tap water contamination (median=40,000; range 1,100-43,000 cfu/l). The remaining seven hospitals isolated Legionella spp. exclusively from water samples (median=8,000; range 1,200-70,000 cfu/l)., Conclusions: Our data suggest that environmental Legionella contamination cannot be assessed only through the air sampling, even in the presence of an important water contamination.

Beta-thymosins are structurally related, highly conserved acidic polypeptides, originally isolated from calf thymus. We have recently shown that the TB10 gene is overexpressed in human thyroid carcinoma cell lines and tissues, particularly in undifferentiated thyroid carcinomas, but expressed at an undetectable level in normal thyroid cells. The precise role of thymosin beta-10 (TB10) activity in maintaining the malignant phenotype of thyroid cell lines is unknown. To investigate TB10 function and relevance in a model system we used an antisense methodology to suppress TB10 protein synthesis in two human thyroid carcinoma cell lines (NPA and ARO). The growth in soft agar of NPA and ARO cells carrying a TB10 construct in an antisense orientation was significantly reduced. Conversely, anchorage-dependent growth was unchanged in NPA and ARO cells carrying the TB10 construct in a sense orientation or carrying the backbone vector. TB10 expression also affected actin organization. In fact, stress fibers were long and thick in ARO cells in which TB10 expression was suppressed by the antisense construct. Conversely, they were scarce and short in the vector-transfected ARO cells. These data suggest that TB10 plays a critical role in the regulation of anchorage-independent growth and assembly of actin filaments.