A randomized trial of the efficacy of hand disinfection for prevention of rhinovirus infection.

BACKGROUND: Hand disinfection is frequently recommended for prevention of rhinovirus (RV) infection and RV-associated common colds. The effectiveness of this intervention has not been established in a natural setting. The purpose of this study was to determine the effect of hand disinfection on RV infection and RV-associated common cold illness in a natural setting. METHODS: A controlled clinical trial was done in young adult volunteers during 9 weeks of the fall 2009 RV season. Volunteers were randomized to either an antiviral hand treatment containing 2% citric acid and 2% malic acid in 62% ethanol (n = 116) or to a no-treatment control group (n = 96). The hand treatment was applied every 3 hours while the subjects were awake. All volunteers kept a daily diary of symptoms and had a nasal lavage for polymerase chain reaction once each week and 2 additional lavages around the time of each common cold illness. The primary endpoint was the number of RV-associated illnesses. The incidence of RV infection and of common cold illnesses were evaluated as secondary endpoints. RESULTS: The hand treatment did not significantly reduce RV infection or RV-related common cold illnesses. The total number of common cold illnesses was significantly reduced in the intent-to-treat analysis, but this effect was not seen in the per protocol analysis. CONCLUSIONS: In this study, hand disinfection did not reduce RV infection or RV-related common cold illnesses. CLINICAL TRIALS REGISTRATION: NCT00993759.

Effectiveness of hand sanitizers with and without organic acids for removal of rhinovirus from hands.

These studies evaluated the effectiveness of ethanol hand sanitizers with or without organic acids to remove detectable rhinovirus from the hands and prevent experimental rhinovirus infection. Ethanol hand sanitizers were significantly more effective than hand washing with soap and water. The addition of organic acids to the ethanol provided residual virucidal activity that persisted for at least 4 h. Whether these treatments will reduce rhinovirus infection in the natural setting remains to be determined.

Alternative hand contamination technique to compare the activities of antimicrobial and nonantimicrobial soaps under different test conditions.

Antimicrobial hand soaps provide a greater bacterial reduction than nonantimicrobial soaps. However, the link between greater bacterial reduction and a reduction of disease has not been definitively demonstrated. Confounding factors, such as compliance, soap volume, and wash time, may all influence the outcomes of studies. The aim of this work was to examine the effects of wash time and soap volume on the relative activities and the subsequent transfer of bacteria to inanimate objects for antimicrobial and nonantimicrobial soaps. Increasing the wash time from 15 to 30 seconds increased reduction of Shigella flexneri from 2.90 to 3.33 log(10) counts (P = 0.086) for the antimicrobial soap, while nonantimicrobial soap achieved reductions of 1.72 and 1.67 log(10) counts (P > 0.6). Increasing soap volume increased bacterial reductions for both the antimicrobial and the nonantimicrobial soaps. When the soap volume was normalized based on weight (approximately 3 g), nonantimicrobial soap reduced Serratia marcescens by 1.08 log(10) counts, compared to the 3.83-log(10) reduction caused by the antimicrobial soap (P < 0.001). The transfer of Escherichia coli to plastic balls following a 15-second hand wash with antimicrobial soap resulted in a bacterial recovery of 2.49 log(10) counts, compared to the 4.22-log(10) (P < 0.001) bacterial recovery on balls handled by hands washed with nonantimicrobial soap. This indicates that nonantimicrobial soap was less active and that the effectiveness of antimicrobial soaps can be improved with longer wash time and greater soap volume. The transfer of bacteria to objects was significantly reduced due to greater reduction in bacteria following the use of antimicrobial soap.

Effect of hand wash agents on controlling the transmission of pathogenic bacteria from hands to food.

The goals of this study were to evaluate the effectiveness of two hand wash regimens in reducing transient bacteria on the skin following a single hand wash and the subsequent transfer of the bacteria to a ready-to-eat food item, freshly cut cantaloupe melon. The number of bacteria recovered from hands and the quantity transferred to the melon were significantly less following the use of an antibacterial soap compared with plain soap. The antimicrobial soap achieved > 3-log reductions versus Escherichia coli and 3.31- and 2.83-log reductions versus Shigella flexneri. The plain soap failed to achieve a 2-log reduction against either organism. The bacteria recovered from the melon handled by hands treated with antimicrobial hand soap averaged 2 log. Melon handled following hand washing with plain soap had > 3 log bacteria in the experiments. Based on previously published feeding studies, an infection rate in the range of approximately 15 to 25% would be expected after ingesting melon containing 2 log CFU compared with ingesting greater than the 3 log transferred from hands washed with plain soap, which would result in a higher infection attack rate of 50 to 80%. The data thus demonstrate there is a greater potential to reduce the transmission and acquisition of disease through the use of an antimicrobial hand wash than through the use of plain soap.

The scavenger mRNA decapping enzyme DcpS is a member of the HIT family of pyrophosphatases.

We recently demonstrated that the major decapping activity in mammalian cells involves DcpS, a scavenger pyrophosphatase that hydrolyzes the residual cap structure following 3' to 5' decay of an mRNA. The association of DcpS with 3' to 5' exonuclease exosome components suggests that these two activities are linked and there is a coupled exonucleolytic decay-dependent decapping pathway. We purified DcpS from mammalian cells and identified the cDNA encoding a novel 40 kDa protein possessing DcpS activity. Consistent with purified DcpS, the recombinant protein specifically hydrolyzed methylated cap analog but did not hydrolyze unmethylated cap analog nor did it function on intact capped RNA. Sequence alignments of DcpS from different organisms revealed the presence of a conserved hexapeptide, containing a histidine triad (HIT) sequence with three histidines separated by hydrophobic residues. Mutagenesis analysis revealed that the central histidine within the DcpS HIT motif is critical for decapping activity and defines the HIT motif as a new mRNA decapping domain, making DcpS the first member of the HIT family of proteins with a defined biological function.

Identifying mRNAs bound by RNA-binding proteins using affinity purification and differential display.

Many methods are available and widely used to determine specific proteins that bind to a particular RNA of interest. However, approaches to identify unknown substrate RNAs to which an RNA-binding protein binds and potentially regulates are not as common. In this article we describe a technique termed isolation of specific nucleic acids associated with proteins (SNAAP) that allows the identification of mRNAs associated with a protein. Methods are detailed for expressing and purifying fusion proteins that are used to isolate substrate mRNPs employing differential display technology. Lastly, experiments are described to confirm that the RNAs identified are indeed bonafide substrates for an RNA-binding protein. As the number of known RNA-binding proteins increases, of which many are involved in genetic disorders, it is essential that methodologies exist to identify RNA-protein interactions to better understand the manifestation of disease.

Regulated alpha-globin mRNA decay is a cytoplasmic event proceeding through 3'-to-5' exosome-dependent decapping.

The alpha-globin mRNA contains a C-rich stability element (CRE) in its 3' untranslated region (3' UTR) which is critical for the stability of this long-lived mRNA. A protein complex, termed the alpha-complex, forms on the CRE and has been shown to contribute to stabilization of the mRNA by at least two mechanisms, first by interacting with the poly(A)-binding protein (PABP) to prevent deadenylation, and second by protecting the mRNA from attack by an erythroid endoribonuclease. In this report, we demonstrate that the alpha-globin 3' UTR can confer stability on a heterologous mRNA in cells, and this stability is dependent on the alpha-complex. Moreover, the stability was exclusively detected with cytoplasmic mRNA, suggesting that the regulation of alpha-globin mRNA stability is a cytoplasmic event. An additional mechanism by which the alpha-complex can confer stability on an RNA in vitro was also identified and shown to involve inhibition of 3' to 5' exonucleolytic degradation. Furthermore, using an in vitro mRNA decay system, we were able to follow the demise of the alpha-globin RNA and demonstrate that the decay was initiated by deadenylation followed by 3'-to-5' decay carried out by the exosome and ultimately hydrolysis of the residual cap structure.

Characterization and purification of a mammalian endoribonuclease specific for the alpha -globin mRNA.

The alpha-globin mRNA has previously been shown to be the target of an erythroid-enriched endoribonuclease (ErEN) activity which cleaves the mRNA within the 3'-untranslated region. We have currently undertaken a biochemical approach to purify this enzyme and have begun characterization of the enzyme to determine requirements for substrate recognition as well as optimal cleavage conditions. Through mutational analysis and truncations we show that a 26-nucleotide region of the alpha-globin 3'-untranslated region is an autonomous element that is both necessary and sufficient for cleavage by ErEN. Mutations throughout this region abolish cleavage activity by ErEN suggesting that the entire sequence is important for recognition and cleavage. ErEN is most active under biological salt concentrations and temperature and activity of the enzyme does not require cations. The size for ErEN was estimated by denaturing gel filtration analysis and is approximately 40 kDa. Interestingly, the exquisite specificity of ErEN cleavage became compromised with increased purity of the enzyme suggesting the involvement of other proteins in specificity of ErEN cleavage. Nondenaturing gel filtration of MEL extract demonstrated that ErEN is a component of an approximately 160 kDa complex implying that additional proteins may regulate ErEN activity and provide increased cleavage specificity.