Non-use of cancer information services among people experiencing cancer in Ireland.

PURPOSE: The purpose of this study was to explore the reasons for non-use of a national cancer society's cancer information services among people experiencing cancer. METHOD: This study used a qualitative design. Semi-structured interviews were conducted with a total of 17 participants who had not previously utilised the Cancer Society's information services. Data were analysed using Thematic Analysis. RESULTS: The key themes to emerge from the date were 'living in the here and now' and 'awareness of the Cancer Society'. For most participants, not utilising cancer information services was a means of coping with the initial diagnosis and the impact of treatment. Those who progressed to being ready to seek information identified the multi-disciplinary team as the primary source of trusted information, with particular mention of cancer nurse specialists. For participants with children, their role as a parent was central in how they managed their diagnosis. The majority of participants lacked awareness of the range of services provided by the Cancer Society. CONCLUSIONS: Reasons for non-use of cancer information services were identified as: readiness to seek information and a lack of knowledge of the Cancer Societies' services. Cancer information services need to continue make a concerted effort to enhance visibility and awareness of its services to optimise patient engagement.

Subunit dissociation of Busycon canaliculatum hemocyanin.

The hemocyanin of the channeled whelk, Busycon canaliculatum, is a multisubunit protein with a molecular weight close to 9 X 10(6). The increase in pH above neutrality and the addition of 0-5 M urea and 0-2 M GdnHCl is found to dissociate the whole molecules to half-molecules and smaller dimeric and monomeric fragments of one-tenth and one-twentieth mass of the parent hemocyanin. The molecular weight transitions investigated at constant protein concentration of 5 X 10(-2) g X l-1 show no clearly discernible plateau regions, where essentially only half-molecules and one-tenth molecules are present. The ultracentrifugation patterns in much of the dissociation region produced by urea at pH 6.9 suggests the presence of three distinct components consisting of whole molecules, half-molecules and largely one-tenth molecular weight fragments. At pH 8.2 and higher, where whole molecules are largely absent, the effects of urea on the dissociation of half-molecules to tenths and tenth-molecules to twentieth molecule was investigated by means of light scattering. Analysis of the urea data based on a decamer to dimer and dimer to monomer scheme of dissociation used in our earlier studies gave apparent estimates of about 90 amino acid groups at the contact areas of the dimers in the half-molecules and 110 groups at the monomer contacts forming the dimers. The latter relatively large estimate of groups suggests that the dissociation of the tenth molecules or dimers must occur by longitudinal splitting of the contact areas along both the folded domains and the connecting chain segments of the twentieth molecules. Circular dichroism, absorbance and viscosity data suggest that the secondary structure and conformation of the folded domains of the hemocyanin subunits are largely retained at both high pH and in 3-8 M urea solutions. The molecular weights at pH 9.0-10.6 and in 3-8 M urea are found to be (4.2-4.7) X 10(5), close to one-twentieth of the mass of the parent hemocyanin. Denaturation and unfolding of the subunit domains is observed between 3 and 6 M GdnHCl solutions, as evidenced by the abolition of the characteristic copper absorbance in the neighborhood of 346 nm and the relatively pronounced changes in circular dichroism at 222 nm and intrinsic viscosity. The further decrease in molecular weights to about (2.6-3.2) X 10(5), below one-twentieth of the mass of hemocyanin suggests the presence of hidden breaks or scissions in the polypeptide chains suffered during isolation, which become exposed as a result of complete unfolding in GdnHCl solutions.(ABSTRACT TRUNCATED AT 400 WORDS)

A fluorescence study of the interaction of protein synthesis initiation factors 4A, 4E, and 4F with mRNA and oligonucleotide analogs.

The initial interaction of mRNA with the protein synthesis machinery presumably involves recognition of the 5'-cap (m7GpppN), although it is not clear at the present time whether this recognition is by eIF-4E or eIF-4F. This process has been studied by direct fluorescence titration experiments. The equilibrium constants for the formation of the binary protein: m7GpppG, protein:mRNA, and protein:protein complexes as well as the ternary mRNA:eIF-4E:eIF-4A complexes were measured. These studies show, for the first time, direct evidence for an eIF-4A:eIF-4E interaction. In contrast to earlier studies, we show that the affinity of eIF-4E and eIF-4F for globin mRNA is similar. Furthermore, the relative affinities of mRNA analogs (capped oligonucleotides) for these initiation factors indicate that the cap is the predominant feature recognized for binding, but other features also contribute to the eIF-4E:mRNA interaction.

Reactions of stereoisomeric and structurally related bay region diol epoxide derivatives of benz[a]anthracene with DNA. Conformations of noncovalent complexes and covalent carcinogen-DNA adducts.

The modes of reaction of the tumorigenic bay region diol epoxide anti-BADE [+/-)-trans-3,4-diol-anti-1,2-epoxy-1,2,3,4-tetrahydrobenz[a]anthr acene) and the less potent tumor initiating diastereomer syn-BADE [+/-)-trans-3,4-diol-syn-1,2-epoxy-1,2,3,4-tetrahydrobenz[a]anthra cene) with native, double-stranded DNA were compared. The bay-region diol epoxide derived from 3-methylcholanthrene (3-MCDE, racemic trans-9,10-diol-anti-7,8-epoxy-7,8,9,10-tetrahydromethylcholanthrene+ ++) was included in this study in order to assess the effects of the methyl and methylene substituents on the reactivity with DNA. Utilizing linear dichroism and other spectroscopic methods, it is shown that all three diol epoxides forn non-covalent complexes with DNA. The diastereomers anti-BADE and syn-BADE form intercalative physical complexes, but the association constant K of the syn-diastereomer is about 6-7 times smaller than for anti-BADE; this effect is ascribed to the bulky quasi-diaxial conformation of the diol epoxide ring in the syn diastereomer. The value of K (4000 M-1) is similar for anti-BADE and 3-MCDE, although the latter is not intercalated in the classical sense since the short axis of the molecule is tilted closer to the axis of the DNA double helix. The conformations of the covalent DNA adducts are interpreted in terms of a quasi-intercalative conformation (site I), and a conformation in which the long axes of the polycyclic molecules are tilted closer to the axis of the helix (site II). Both tumorigens, anti-BADE and 3-MCDE, undergo a marked re-orientation from a non-covalent site I to a covalent site II conformation upon binding chemically with the DNA bases, although a small fraction of the covalent anti-BADE adducts remains quasi-intercalated; in contrast, the alkyl substituents in 3-MCDE not only prevent the formation of intercalative physical complexes, but also the formation of site I covalent adducts. In the case of the less tumorigenic syn-BADE, both the non-covalent complexes and the covalent adducts are of the site I-type. The bay-region diol epoxide of benz[a]anthracene and of 3-methylcholanthrene display a similar pattern of reactivities and covalent adduct conformations as the bay region diol epoxide derivatives of benz[a]pyrene, suggesting that adduct conformation might be an important factor in determining the levels of mutagenic and tumorigenic activities of this class of compounds.

Updated estimate of trans fat intake by the US population.

The dietary intake of industrially-produced trans fatty acids (IP-TFA) was estimated for the US population (aged 2 years or more), children (aged 2-5 years) and teenage boys (aged 13-18 years) using the 2003-2006 National Health and Nutrition Examination Survey (NHANES) food consumption database, market share information and trans fat levels based on label survey data and analytical data for packaged and in-store purchased foods. For fast foods, a Monte Carlo model was used to estimate IP-TFA intake. Further, the intake of trans fat was also estimated using trans fat levels reported in the US Department of Agriculture (USDA) National Nutrient Database for Standard Reference, Release 22 (SR 22, 2009) and the 2003-2006 NHANES food consumption database. The cumulative intake of IP-TFA was estimated to be 1.3 g per person per day (g/p/d) at the mean for the US population. Based on this estimate, the mean dietary intake of IP-TFA has decreased significantly from that cited in the 2003 US Food and Drug Administration (FDA) final rule that established labelling requirements for trans fat (4.6 g/p/d for adults). Although the overall intake of IP-TFA has decreased as a result of the implementation of labelling requirements, individuals with certain dietary habits may still consume high levels of IP-TFA if certain brands or types of food products are frequently chosen.

Characterization of the interaction of wheat germ protein synthesis initiation factor eIF-3 with mRNA oligonucleotide and cap analogues.

Direct fluorescence titration experiments of wheat germ protein synthesis initiation factor eIF-3 with mRNA cap and oligoribonucleotide analogues were performed in order to determine the equilibrium association constants (Keq) for the eIF-3.mRNA interaction as a function of pH and temperature. These data suggest that (i) the eIF-3.mRNA interaction is not cap-specific (i.e., m7G-specific), (ii) ATP hydrolysis is not involved in the interaction, and (iii) the interaction is primarily ionic in nature. Competition experiments between a rabbit alpha-globin mRNA oligoribonucleotide analogue and either mRNA cap analogues or nucleoside triphosphates (NTPs) are also reported; these experiments indicate that NTPs act as both activators and competitive inhibitors of the mRNA.eIF-3 association. The results are consistent with a partially uncompetitive binding mechanism, whereby at low NTP concentrations (less than or equal to 10 microM) the bound NTP enhances subsequent mRNA binding to eIF-3, perhaps by inducing a conformational change, and at higher NTP concentrations, the NTP acts as a competitive inhibitor for the mRNA binding site on eIF-3.

Interaction of wheat germ protein synthesis initiation factors eIF-3, eIF-(iso)4F, and eIF-4F with mRNA analogues.

The interaction of wheat germ eIF-3 with the wheat germ cap-binding proteins eIF-(iso)4F and eIF-4F as a function of pH and ionic strength is described. Direct fluorescence titration experiments are used to measure the equilibrium association constants (Keq) for the binary protein/protein complexes as well as for the interaction of eIF-3 with methylated cap analogues and rabbit alpha-globin mRNA oligonucleotide analogues. The Keq values for ternary eIF-3/eIF-(iso)4F/analogue and eIF-3/eIF-4F/analogue interactions were also measured. The equilibrium binding constants were used to calculate coupling free energies, which provide an estimate of the cooperativity for the interaction of the mRNA analogues, eIF-3, and either eIF-4F or eIF-(iso)4F. These data suggest a mechanism in which the binding of eIF-(iso)4F or eIF-4F to mRNA enhances the subsequent binding of eIF-3 to the message. This may lead to favorable positioning of the complex on the ribosome and thereby enhance translation.

Wheat germ initiation factors 4F and (iso)4F interact differently with oligoribonucleotide analogues of rabbit alpha-globin mRNA.

The binding of capped oligoribonucleotide analogues of the 5' terminus of rabbit alpha-globin mRNA to wheat germ protein synthesis initiation factors eIF-4F and eIF-(iso)4F was measured by direct fluorescence techniques. An analysis of the equilibrium association constants (Keq) indicates that both eIF-4F and eIF-(iso)4F recognize primarily the m7G cap structure but differ in the recognition of other structural features. eIF-4F is sensitive to the position and sequence of hairpin structures within the oligoribonucleotide, while eIF-(iso)4F shows a preference for linear sequences. These differences suggest that wheat germ eIF-4F and eIF-(iso)4F may have discriminatory activity for mRNA recognition.

A spectroscopic study of the binding of m7GTP and m7GpppG to human protein synthesis initiation factor 4E.

The binding of analogues of the 7-methylguanosine-containing cap, m7GTP and m7GpppG, to eIF-4E from human erythrocytes as a function of pH, temperature, and ionic strength is described. From the pH-dependent binding of m7GTP and m7GpppG to eIF-4E, a new model describing the nature of the cap.eIF-4E interaction is proposed. The thermodynamic values and ionic strength dependence of binding are consistent with a binding site which is primarily hydrophobic. Fluorescence and circular dichroism data indicate that tryptophan residues may be involved in base-stacking interactions with the cap in a somewhat buried environment. The model presented here confirms the earlier proposal [Rhoads et al. (1983) Biochemistry 22, 6084-6088] that the enolate tautomer of the cap is preferred for interaction and further proposes that the interaction is with a protonated amino acid residue, such as histidine, while stacking with an aromatic amino acid, such as tryptophan.

Reactions of stereoisomeric non-bay-region benz[a]anthracene diol epoxides with DNA and conformations of non-covalent complexes and covalent adducts.

The reactions of the non-bay-region diol epoxides racemic trans-8,9-dihydroxy-anti-10,11-epoxy-8,9,10,11-tetrahydrobenz[a]an thracene (anti-BA-10,11-DE) and racemic trans-8,9-dihydroxy-syn-10,11-epoxy-8,9,10,11-tetrahydrobenz[a]ant hracene (syn-BA-10,11-DE) with native double-stranded DNA in aqueous solutions (5 mM sodium cacodylate buffer, pH 7.0, 23 degrees C) was investigated utilizing various spectroscopic techniques. The results of linear dichroism experiments suggest that both diastereomers form non-covalent, intercalative complexes with DNA prior to undergoing chemical reactions; the association constant for the anti stereoisomers is about twice as large (850 +/- 100 M-1) as that for the syn-diastereomers, thus qualitatively paralleling the behavior established previously for the bay-region diol epoxides of benzo[a]pyrene and benz[a]anthracene. The reaction rates of both anti- and syn-BA-10,11-DE are significantly accelerated in the presence of DNA, and the fraction of diol epoxide molecules which bind covalently to DNA is 13 +/- 2% and 3 +/- 1% respectively; these levels of covalent binding are lower by factors of about two respectively, than in the case of the bay-region diol epoxides of benz[a]anthracene. The phenanthrenyl residues in the covalent anti-BA-10,11-DE-DNA adducts are tilted with their long axes closer to the average orientations of the normals to the DNA bases; in contrast, the adducts derived from the binding of the syn diastereomers, appear to be characterized by intercalative-type conformations; however, the overall degrees of orientations are weak in the cases of these non-bay-region diol epoxide-DNA adducts. Nevertheless, these adduct conformations resemble those derived from the highly tumorigenic anti and the less active syn diasteromers of benzo[a]pyrene and benz[a]anthracene, thus providing one additional example to the previously observed correlations between adduct structure and biological activity.

A comparison of the binding of methylated cap analogues to wheat germ protein synthesis initiation factors 4F and (iso)4F.

The binding of the 5'-terminal cap analogues m7GpppG and m7GTP to wheat germ protein synthesis initiation factors eIF-4F and eIF-(iso)4F as a function of pH, ionic strength, and temperature is described. Equilibrium binding data indicate that eIF-4F and eIF-(iso)4F have different mechanisms for interacting with the 5'-cap structure, but the complexes formed between m7GpppG and wheat germ factor eIF-(iso)4F more closely resemble complexes formed between this cap analogue and either mammalian eIF-4E or eIF-4F. The binding of these initiation factors to the hypermethylated cap analogues m2,7GMP, m2,7GpppG, and m2,2,7GpppG is also investigated. The differences in affinity of eIF-4F and eIF-(iso)4F for the hypermethylated 5'-terminal cap structures suggest that these factors may have discriminatory activity.

Linear dichroism characteristics of ethidium-and proflavine-supercoiled DNA complexes.

A flow linear dichroism technique is utilized to study the unwinding of supercoiled DNA induced by the binding of ethidium bromide (EB) and proflavine (PF) at different ratios r (drug added/DNA base). In the case of either EB or PF bound to linear calf thymus DNA, the reduced linear dichroism signals LD/A (LD: linear dichroism; A: absorbance, both measured at the same wavelength), determined at 258, and 520 or 462 nm (corresponding to contributions predominantly from the partially oriented DNA bases, intercalated EB, or PF, respectively) are nearly independent of drug concentration. In the case of supercoiled DNA, the magnitude of LD/A at 258 nm first increases to a maximum value near r = 0.04-0.05, and then decreases as r is increased further, mimicking the behavior of the sedimentation coefficients, viscosities, and gel electrophoresis patterns measured by other workers at similar values of r. However, LD/A at 520 nm, which is due to DNA-bound EB molecules, is constant within the range of r values of 0.02-0.06 in which the magnitude of LD/A determined at 258 nm due to the DNA bases exhibits a pronounced maximum. In contrast, in the case of PF, the magnitudes of LD/A determined at 258 or 462 nm are characterized by similar dependencies on r, both exhibiting pronounced maxima at r = 0.05; this parallel behavior is expected according to a simple intercalation model in which the DNA bases and drug molecules are stacked on top of one another, and in which both are oriented to similar extents in the flow gradient. The unexpected differences in the dependencies of (LD/A)258 and (LD/A)520 on r in the case of EB bound to supercoiled DNA, are attributed to differences in the net overall alignment of the EB molecules and DNA bases in the flow gradient. The magnitude of the LD signal at 258 nm reflects the overall degree of orientation of the supercoiled DNA molecules that, in turn, depends on their hydrodynamic shapes and sizes; the LD signals characterizing the bound EB molecules may reflect this orientation also, as well as the partial alignment of individual DNA segments containing bound EB molecules.(ABSTRACT TRUNCATED AT 400 WORDS)

Integrating communicative goals for real-time clinical decision support.

A critiquing system evaluating a physician's management plan may produce a set of individual comments that, taken together, appear repetitious or incoherent. This paper presents TraumaGEN, a system for integrating sets of possibly inter-related communicative goals into one or more coherent messages. TraumaGEN takes account of the purpose of the messages, the situation in which the messages will be received, and the social role of the system. Preliminary evaluation of TraumaGEN indicates that it produce coherent integrated messages.

Binding of protein synthesis initiation factor 4E to oligoribonucleotides: effects of cap accessibility and secondary structure.

The binding of rabbit globin mRNA to the 25-kDa cap binding protein eIF-4E from human erythrocytes was found to be 5.3-fold stronger than the binding of the cap analogue m7GpppG to eIF-4E [Gross et al. (1990) Biochemistry 29, 5008-5012]. In order to investigate whether this effect is due to the longer sequence of nucleotides in globin mRNA or to other features such as cap accessibility or secondary structure, oligoribonucleotide analogues of rabbit alpha-globin mRNA were synthesized by T7 RNA polymerase from a synthetic oligodeoxynucleotide template in the presence of m7GpppG; these oligoribonucleotide analogues possess varying degrees of cap accessibility and secondary structure. Equilibrium association constants for the interaction of these oligoribonucleotides and purified human erythrocyte eIF-4E were obtained from direct fluorescence titration experiments. The data indicate that while the presence of the m7G cap is required for efficient recognition by eIF-4E, the cap need not be completely sterically accessible, since other structural features within the mRNA also influence binding.

Differences in unwinding of supercoiled DNA induced by the two enantiomers of anti-benzo[a]pyrene diol epoxide.

The unwinding of supercoiled phi X174 RFI DNA induced by the tumorigenic (+) and non-tumorigenic (-) enantiomers of trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) has been investigated by agarose slab-gel and ethidium titration tube gel electrophoresis. The differences in adduct conformations were verified by flow linear dichroism techniques. Both enantiomers cause a reversible unwinding by the formation of noncovalent intercalative complexes. The effects of covalently bound BPDE residues on the electrophoretic mobilities of the RF I DNA form in agarose gels were investigated in detail in the range of binding ratios rb approximately 0.0-0.06 (covalently bound BPDE residues/nucleotide). In this range of rb values, there is a striking difference in the mobilities of (+)-BPDE- and (-)-BPDE-adducted phi X174 DNA in agarose slab-gels, the covalently bound (+)-BPDE residues causing a significantly greater retardation than (-)-BPDE residues. Increasing the level of covalent adducts beyond rb approximately 0.06 in the case of the (+)-BPDE enantiomer, leads to further unwinding and a minimum in the mobilities (corresponding to comigration of the nicked form and the covalently closed relaxed modified form) at rb 0.10 +/- 0.01; at still higher rb values, rewinding of the modified DNA in the opposite sense is observed. From the minimum in the mobility, a mean unwinding angle (per BPDE residue) of theta = 12 +/- 1.5 degrees is determined, which is in good agreement the value of theta = 11 +/- 1.8 degrees obtained by the tube gel titration method. Using this latter method, values of theta = 6.8 +/- 1.7 degrees for (-)-BPDE-phi X174 adducts are observed. It is concluded that agarose slab gel techniques are not suitable for determining unwinding angles for (-)-BPDE-modified phi X174 DNA because the alterations in the tertiary structures for rb < 0.06 are too small to cause sufficiently large changes in the electrophoretic mobilities. The major trans (+)-BPDE-N2-guanosine covalent adduct is situated at external binding sites and the mechanisms of unwinding are therefore different from those relevant to noncovalent intercalative BPDE-DNA complexes or to classical intercalating drug molecules; a flexible hinge joint and a widening of the minor groove at the site of the lesion may account for the observed unwinding effects. The more heterogeneous (-)-BPDE-nucleoside adducts (involving cis and trans N2-guanosine, and adenosine adducts) are less effective in causing unwinding of supercoiled DNA for reasons which remain to be elucidated.

Characterization of the ATP-dependent binding of wheat germ protein synthesis initiation factors eIF-(iso)4F and eIF-4A to mRNA.

The ATP-dependent binding of wheat germ protein synthesis initiation factors eIF-(iso)4F and eIF-4A to an oligoribonucleotide has been investigated by direct fluorescence titration techniques. In addition, the effect of ATP on the interaction between another cap-binding initiation factor, eIF-4F, and eIF-4A was studied using the same methods. Comparison of the equilibrium association constants (K(eq)) indicate that 1) hydrolyzable ATP affects the affinity of eIF-(iso)4F for eIF-4A, regardless of whether or not mRNA was previously bound to the eIF-(iso)4F; in contrast, ATP had no effect on the eIF-(iso)4F/oligoribonucleotide interaction; 2) in the presence of ATP, the binding of the binary eIF-(iso)4F.eIF-4A complex to the oligoribonucleotide is of similar affinity as the binding of the oligoribonucleotide to the eIF-(iso)4F alone; the stoichiometry of this ternary eIF-(iso)4F.eIF-4A.mRNA complex was found to be 1:1:1; and 3) a similar ATP effect is observed for the eIF-4F/eIF-4A interaction as for the eIF-(iso)4F.eIF-4A complex.

A spectroscopic study of the binding of N-7-substituted cap analogues to human protein synthesis initiation factor 4E.

The binding of N-7-substituted cap analogues to eIF-4E from human erythrocytes is described. Data presented here indicate that there is a correlation between the tightness of binding of these cap analogues to eIF-4E and their potency as inhibitors of protein synthesis. This result indicates that the inhibitory activity of the cap analogues is strictly a function of the affinity of the analogue for eIF-4E under equilibrium conditions. The pH dependence of binding of the cap analogues to eIF-4E indicates that the enolate form of the cap is preferred, as originally postulated by Rhoads et al. [(1983) Biochemistry 22, 6084-6088]. Data indicate that there are differences in the mode of binding of alkyl-substituted and aryl-substituted cap analogues to eIF-4E arising from favorable interactions of the phenyl ring with the guanosine moiety. These differences may explain the enhanced recognition of the aryl-substituted cap analogues by eIF-4E.

Fluorescence study of the binding of m7GpppG and rabbit globin mRNA to protein synthesis initiation factors 4A, 4E, and 4F.

The interactions of protein synthesis initiation factors eIF-4E from human erythrocytes and eIF-4A and eIF-4F from rabbit reticulocytes with the cap analogue m7GpppG and rabbit globin mRNA were investigated. The equilibrium binding constants for the binary complex formation of eIF-4E-eIF-4A, m7GpppG-eIF-4E, m7GpppG-eIF-4F, globin mRNA-eIF-4E, globin mRNA-eIF-4F, and globin mRNA-eIF-4A were measured by direct fluorescence titration experiments. The binding of eIF-4E to globin mRNA was found to be 5.5-fold tighter than its binding to m7GpppG; the binding of eIF-4F for globin mRNA and m7GpppG was similar to that of eIF-4E. Association equilibrium constants were determined for the ternary system mRNA-eIF-4E-eIF-4A; four thermodynamically independent equilibria characterize the system. These equilibrium binding constants were used to calculate coupling free energies, which provided an estimate of the cooperativity of the interaction of eIF-4E, eIF-4A, and mRNA. These coupling energies were all found to be small and positive, indicative of anticooperative binding.