[Hand hygiene in intensive care]. / "Mani pulite" in terapia intensiva.

Hand hygiene represents the main way to prevent and/or at least reduce nosocomial infection incidence. In this paper we discuss this "hot topic" through both the analysis of CDC guide lines and the data resulting from a questionnaire survey sent to health care workers, eventually corroborated by their direct observation. From literature data and our survey result analyses, we are more than convinced that the winning strategies for a slow but progressive improvement of hand washing practice and compliance are (i). using a product able to decontaminate hands very quickly and without needing water; (ii). the health care worker awareness of hand hygiene and compliance feed-back importance. From our questionnaire survey as well as from our direct observation, we found a very low (5.6%) compliance of our hospital health care workers to CDC guidelines for hand washing. This may be justified above all by ward logistical and structural problems, as only 55% of sinks are located inside patient rooms, but also because there is a lacking of knowledge of new CDC suggested practices and decontaminating products. Health care worker specific training and the choice of an alcoholic antiseptic disinfectant, allowed us to significantly increase their compliance to proper practices in hand washing and hygiene, showing their interest in such an important and delicate matter.

Sequence-specific binding of human immunodeficiency virus type 1 nucleocapsid protein to short oligonucleotides.

We have analyzed the binding of recombinant human immunodeficiency virus type 1 nucleocapsid protein (NC) to very short oligonucleotides by using surface plasmon resonance (SPR) technology. Our experiments, which were conducted at a moderate salt concentration (0.15 M NaCl), showed that NC binds more stably to runs of d(G) than to other DNA homopolymers. However, it exhibits far more stable binding with the alternating base sequence d(TG)n than with any homopolymeric oligodeoxyribonucleotide; thus, it shows a strong sequence preference under our experimental conditions. We found that the minimum length of an alternating d(TG) sequence required for stable binding was five nucleotides. Stable binding to the tetranucleotide d(TG)2 was observed only under conditions where two tetranucleotide molecules were held in close spatial proximity. The stable, sequence-specific binding to d(TG)n required that both zinc fingers be present, each in its proper position in the NC protein, and was quite salt resistant, indicating a large hydrophobic contribution to the binding. Limited tests with RNA oligonucleotides indicated that the preferential sequence-specific binding observed with DNA also occurs with RNA. Evidence was also obtained that NC can bind to nucleic acid molecules in at least two distinct modes. The biological significance of the specific binding we have detected is not known; it may reflect the specificity with which the parent Gag polyprotein packages genomic RNA or may relate to the functions of NC after cleavage of the polyprotein, including its role as a nucleic acid chaperone.

A new major histocompatibility complex class I b gene expressed in the mouse blastocyst and placenta.

Because of the role major histocompatibility complex (MHC) class I b molecules may play during mouse embryonic development, we thought it would be interesting to search for additional MHC class I b molecules that might be expressed in preimplantation embryos, and in particular in the trophoblastic lineage. We therefore screened a mouse preimplantation blastocyst cDNA library for MHC class I sequences. This search led to the identification and characterization of a new MHC class I b gene, blastocyst MHC. Sequences identical to the exons and 3' untranslated region of this gene have been found in many laboratory mouse strains, as well as in the related mouse species Mus spreciligus. The presence of this gene in mouse strains of different MHC class I haplotypes argues that blastocyst MHC is a unique, newly-described gene rather than a new allele of a previously described mouse MHC class I gene. Blastocyst MHC has the structure of an MHC class I b gene, with the six exons characteristic of T-region genes. It is linked to H2-D. The amino acid sequence encoded by this gene maintains all the features of a functional antigen-presentation domain. The blastocyst MHC gene, like the human class I b gene HLA-G, is expressed at the blastocyst stage and in the placenta, and may be the mouse analog for HLA-G.

The protein tyrosine kinase P59fyn is associated with prolactin (PRL) receptor and is activated by PRL stimulation of T-lymphocytes.

The clonal expansion of antigen-stimulated T-lymphocytes during an immune response is mediated by several lymphokines. Strong evidence now exists that the neuroendocrine hormone PRL is necessary, but not sufficient, for T-cell proliferation. Little is known, however, of the signal transduction mechanisms of the PRL receptor (PRLR) within T-cells. We demonstrate here that PRL stimulation of the T-cell line Nb2 induced the concentration- and time-dependent activation of the protein tyrosine kinase p59fyn, but not of four other src family protein tyrosine kinases. Activation of fyn was also observed in Concanavalin-A-primed peripheral blood lymphocytes stimulated with PRL and in Nb2 cells incubated with anti-PRLR antibodies. The activation of fyn by PRL stimulation correlated with Nb2 cell proliferation. Immunoblot analysis of anti-fyn and anti-PRLR immune complexes revealed an association between each PRLR isoform and p59fyn. These studies demonstrate for the first time an association between the PRLR and a src family protein tyrosine kinase affiliated with signal transduction.