DNA aptamers were selected against recombinant human (rhu) cellular prion protein (PrP(C)) 23-231 by systematic evolution of ligands via a systematic evolution of ligands by exponential (SELEX) enrichment procedure using lateral flow chromatography. The SELEX procedure was performed with an aptamer library consisting of a randomized 40-nucleotide core flanked by 28-mer primer-binding sites that, theoretically, represented approximately 10(24) distinct nucleic acid species. Sixty nanograms of rhuPrP(C)23-231 immobilized in the center of a lateral flow device was used as the target molecule for SELEX. At the end of 6 iterations of SELEX, 13 distinct candidate aptamers were identified, of which, 3 aptamers represented 32%, 8%, and 5% of the sequences respectively. Eight aptamers, including the three most frequently occurring candidates, were selected for further evaluation. Selected aptamers bound to rhuPrP(C)23-231 at 10(-6) M to 10(-8) M concentrations. Two of the eight aptamers bound at higher concentrations to rhuPrP(C)90-231. Theoretical thermodynamic modeling of selected aptamer sequences identified several common motifs among the selected aptamers that could play a role in PrP binding. Binding affinity to rhuPrP(C)23-231 was both aptamer sequence and structure dependent. Further, selected aptamers bound to mammalian PrPs derived from brain of healthy sheep, calf, piglet, and deer, and to PrP(C) expressed in mouse neuroblastoma cells. None of the aptamers bound to proteinase K-digested scrapie-infected mouse neuroblastoma cells or untreated PrP-null cells, which further confirmed the PrP(C) specificity of the aptamers. In summary, we enriched and selected DNA aptamers that bind specifically to rhuPrP(C) and mammalian PrP(C) with varying affinities and can be applied to biological samples for PrP(C) enrichment and as diagnostic tools in double ligand assay systems.

The antiterminator Q gene of bacteriophage 933W ( Q 933 ) was identified upstream of the stx 2 gene in 90% of human disease–origin Escherichia coli O157:H7 isolates and in 44.5% of bovine isolates. Shiga toxin production was higher in Q 933 -positive isolates than Q 933 -negative isolates. This genetic marker may provide a useful molecular tool for epidemiologic studies.

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Pattern recognition as a caring partnership in families with cancer The purpose of this study was to address the process of a caring partnership by elaborating pattern recognition as nursing intervention with families with cancer. It is based on Newman's theory of health as expanding consciousness within the unitary-transformative paradigm and is an extension of a previous study of Japanese women with ovarian cancer. A hermeneutic, dialectic method was used to engage 10 Japanese families in which the wife-mothers were hospitalized because of cancer diagnosis. The family included at least the woman with cancer and her primary caregiver. Each of four nurse-researchers entered into partnership with a different family and conducted three interviews with each family. The participants were asked to describe the meaningful persons and events in their family history. The family's story was transmuted into a diagram of sequential patterns of interactional configurations and shared with the family at the second meeting. Evidence of pattern recognition and insight into the meaning of the family pattern were identified further in the remaining meetings. The data revealed five dimensions of a transformative process. Most families found meaning in their patterns and made a shift from separated individuals within the family to trustful caring relationships. One-third of them went through this process within two interviews. The families showed increasing openness, connectedness and trustfulness in caring relationships. In partnership with the family, each nurse-researcher grasped the pattern of the family as a whole and experienced the meaning of caring. Pattern recognition as nursing intervention was a meaning-making transforming process in the family-nurse partnership.

The effects of immunization with the ferric citrate receptor FecA on antibody responses and on experimentally induced mastitis following intramammary challenge were investigated. Twenty-one cows were assigned to seven blocks of three cows based on expected parturition. Cows within block were randomly assigned to one of three treatments: 1) FecA immunization, 2) Escherichia coli J5 immunization, and 3) unimmunized controls. Challenge was by infusion of approximately 60 cfu of E. coli 727 into one uninfected mammary gland between 13 and 31 d after parturition. Cows within block were challenged on the same day. Cows immunized with FecA had higher immunoglobulin (Ig)G titers against FecA in serum and in mammary secretions at calving, immediately before challenge, and 7 d after challenge than did cows immunized with E. coli J5 or control cows. Immunization with FecA also increased IgG titers against whole-cell E. coli 727 in serum and in mammary secretions at calving. Serum IgM titers against FecA were higher in FecA immunized cows than in other treatment groups immediately before challenge. Bacterial counts in milk, duration of bacterial isolation in milk, rectal temperature, and milk somatic cell counts following intramammary challenge were similar among treatments. Milk production and dry matter intake did not differ among treatments. The ferric citrate receptor FecA was immunogenic in cows, but immunization had minimal effect on the clinical severity of experimentally induced E. coli mastitis.