The recognition and non-recognition of problem-solving stages in nursing practice

A requirement for high-quality individualized nursing care is that nurses must recognize and attempt to solve patients' health problems. In this study, it was decided to investigate problem solving using a model similar to the nursing process derived from the general literature. Insight into nurses' perceptions and understanding of problem solving was gained by interviewing 116 nurses using vignettes of clinical problem solving. Data analysis revealed that many informants failed to discuss some problem-solving stages, in particular planning and evaluation. Conversely, problem assessment and implementation attracted more comment. The implications for these variations in nurses' problem-solving behaviour are examined in relation to contemporary nursing issues.

How common are epileptic seizures in old age?

A large primary-care computerized database was searched to determine the incidence and prevalence of epilepsy and epileptic seizures in old age compared with the general population. The prevalence of subjects with a diagnosis of epileptic seizures was higher in older age groups: 10.9/1000 for sexagenarians, 12.0 for septuagenarians and 13.1 for those over 80, compared with 9.0/1000 in the overall population. The overall prevalence in subjects aged over 60 was 11.8. Annual incidence rose even more sharply in old age: 76/100,000 for sexagenarians, 147 for septuagenarians, and 159 for those over 80, compared with an overall population incidence of 69/100,000. The overall incidence in subjects over 60 was 117. Of incident cases requiring treatment, 35.5% were over 60 years old. Our findings are in keeping with other recent epidemiological studies and in part reflect the age-associated increase in the prevalence of cerebrovascular disease. They have implications for the organization of services for elderly people, for the education of general practitioners and hospital doctors and for directing epilepsy research.

Transcriptional role of a conserved GATA-1 site in the human epsilon-globin gene promoter

The epsilon-globin gene is the first of the human beta-like globin genes to be expressed during development. We have analyzed protein-DNA interactions in the epsilon-globin promoter region by DNase I footprinting and electrophoretic mobility shift experiments using nuclear extracts from K562 human erythroid cells and from nonerythroid HeLa cells. A restricted set of ubiquitous proteins, including Sp1, bound to regions of the promoter including the CACCC and CCAAT sites. Three interactions, at positions -213, -165, and +3 relative to the transcription start site, were erythroid specific and corresponded to binding of GATA-1, a transcription factor highly restricted to the erythroid lineage. Interestingly, the GATA-1 site at -165 has been conserved in the promoters of 10 mammalian embryonic globin genes. Point mutations demonstrate that GATA-1 binding to this site is necessary for interaction with an erythroid-specific enhancer but that in the absence of an enhancer, GATA-1 does not increase transcription.

Yeast alpha 2 repressor positions nucleosomes in TRP1/ARS1 chromatin

The yeast alpha 2 repressor suppresses expression of a-mating-type-specific genes in haploid alpha and diploid a/alpha cell types. We inserted the alpha 2-binding site into the multicopy TRP1/ARS1 yeast plasmid and examined the effects of alpha 2 on the chromatin structure of the derivative plasmids in alpha cells, and a/alpha cells. Whereas no effect on nucleosome position was observed in a cells, nucleosomes were precisely and stably positioned over sequences flanking the alpha 2 operator in alpha and a/alpha cells. In addition, when the alpha 2 operator was located upstream of the TRP1 gene, an extended array of positioned nucleosomes was formed in alpha cells and a/alpha cells, with formation of a nucleosome not present in a cells, and TRP1 mRNA production was substantially reduced. These data indicate that alpha 2 causes a positioning of nucleosomes over sequences proximal to its operator in TRP1/ARS1 chromatin and suggest that changes in chromatin structure may be related to alpha 2 repression of cell-type-specific genes.

Effect of transforming growth factor-beta 1 on proliferation and induction of hemoglobin accumulation in K-562 cells

The effects of transforming growth factor-beta 1 (TGF-beta 1) on proliferation and hemoglobinization in K-562 cells, a human multipotential hematopoietic cell line, were studied. We found that TGF-beta 1 could induce hemoglobin accumulation in K-562 cells. Various clones were selected on the basis of the inducibility of hemoglobinization by TGF-beta 1. One high response clone (no. 1) and one low response clone (no. 8) were studied in detail. Hemoglobin accumulation peaked on day 5 of culture in the presence of TGF-beta 1 (0.5 ng/mL, 20 pmol/L), when 90% of clone 1 cells, 55% of parent line cells, and less than 10% of clone 8 cells contained hemoglobin. There was a concomitant reduction in proliferation of 60% for clone 1, 40% for the parent line, and 30% for the clone 8 on day 5 of culture. Quantitative analysis showed that the hemoglobin contents in clone 1 after 5-day induction by TGF-beta 1 and hemin were 1.0 pg/cell and 2.9 pg/cell, respectively. The hemoglobin induced by TGF-beta 1 showed the same electrophoretic characteristics as the hemoglobin induced by hemin. The expression of epsilon-globin mRNA was minimally detectable in control cells and was induced in both TGF-beta 1 and hemin treated cells. Other cytokines with potential effects on K-562 cell proliferation and differentiation were also studied. Interleukin-1, interleukin-3, interferon alpha, interferon gamma, and inhibin, tested as single agents, showed minimal effects on proliferation. None of these agents could induce hemoglobinization or inhibit the hemoglobinization induced by TGF-beta 1.

Measuring the communication of social support from adult children

Further knowledge of the nature and significance of the relationships of elderly persons to their adult children requires the application of social support scales tapping the quality and content of their interactions. Scaling efforts must further address conceptual and operational specification, the differentiation of sources and dimensions of support, the objectification of self-report scales, and construct validity. Respondents to this survey are a community, stratified probability sample of adults aged 50 and older (N = 1,174). Measures employed include 2 items reflecting instrumental support and 17 items designed to tap Cobb's (1976) definition of expressive support as consisting of information that one is loved, esteemed, and embedded in a social relationship characterized by mutual caring and obligation. Factor analyses consistently discern one instrumental and three expressive dimensions of support: Caring and Concern, Social Integration, and Love and Affection. These subscales are differentially correlated with sociodemographic characteristics of the parents and adult children, as well as with depression and disability. Implications of these and other findings are discussed.

Yeast nucleosomes allow thermal untwisting of DNA

Thermal untwisting of DNA is suppressed in vitro in nucleosomes formed with chicken or monkey histones. In contrast, results obtained for the 2 micron plasmid in Saccharomyces cerevisiae are consistent with only 30% of the DNA being constrained from thermal untwisting in vivo. In this paper, we examine thermal untwisting of several plasmids in yeast cells, nuclei, and nuclear extracts. All show the same quantitative degree of thermal untwisting, indicating that this phenomenon is independent of DNA sequence. Highly purified yeast plasmid chromatin also shows a large degree of thermal untwisting, whereas circular chromatin reconstituted using chicken histones is restrained from thermal untwisting in yeast nuclear extracts. Thus, the difference in thermal untwisting between yeast chromatin and that assembled with chicken histones is most likely due to differences in the constituent histone proteins.

An evaluation of the Coulter Counter Model T660

An evaluation of a Coulter Counter Model T660 has been carried out. This instrument is a compact, fully automated, blood cell counter which measures WBC, RBC, Hb, haematocrit, MCV and platelet count on a 100 microliter sample of whole blood. The instrument was assessed during one month of regular use. One possible microbiological hazard was detected, which could be corrected by an instrument modification. No mechanical hazards were identified. The instrument as supplied produced some inaccurate WBCs; this malfunction appeared to be consequent on a design fault relating to the burn circuit of the white cell aperture and following instrument modification performance was considerably improved. Results produced were broadly comparable with those produced by a Coulter Counter Model S Plus IV. Precision was satisfactory. Deviations from linearity on dilution were not sufficient to be of practical importance. Carryover was satisfactorily low. Time-lapse of up to 48 h did not introduce inaccuracy of sufficient magnitude to be of practical importance. Throughout varied from 52 to 63 specimens/h. Following instrument modification the overall assessment was that the T660 was easy to operate, reliable, and clinically useful.

Permissible discontinuity region of the alpha-chain of hemoglobin: noncovalent interaction of heme and the complementary fragments alpha 1-30 and alpha 31-141

Generation of a fragment-complementing system of the alpha-chain on limited proteolysis with Staphylococcus aureus V8 protease has been investigated. Digestion of the alpha-chain (0.4 mM) of hemoglobin with V8 protease in phosphate buffer at pH 6.0 and 37 degrees C is limited to the peptide bonds of Glu-23, Glu-27, Glu-30, and Asp-47. Gel filtration of a V8 protease digest of the alpha-chain on a Sephadex G-50 column did not release any heme to the low molecular weight region, though some peptides were released from the protein. The filtration studies revealed the presence of two heme-containing components in the digest, the major one eluting at the alpha-chain position and the minor one eluting slightly ahead of the alpha-chain position. Reversed-phase high-performance liquid chromatography and amino-terminal sequence analysis demonstrated that the component eluting at the alpha-chain position contains species generated by the noncovalent interactions of heme and the complementary fragments alpha 1-30 and alpha 31-141. In dilute solutions (0.04 mM) the V8 protease digestion occurred exclusively on the carboxyl side of Glu-30(alpha). This high selectivity was also observed at pH 4.0 and pH 7.8. The visible spectra and the ultraviolet circular dichroic spectra of the digest reflect the native-like structure of the noncovalent fragment system. The dissociation constant of alpha 1-30 appears to be in the range of 10(-8) M. In tetrameric hemoglobin A the peptide bond of Glu-30-Arg-31 of the alpha-chain is not accessible to V8 protease digestion.(ABSTRACT TRUNCATED AT 250 WORDS)

An evaluation of the Coulter Counter Model S880

An evaluation of a Coulter Counter Model S880 has been carried out. Certain findings have been further evaluated on a second instrument. Several safety hazards have been identified which could be corrected by minor modifications of the instrument or the mode of operation. Precision was found to be generally satisfactory, though for the platelet count and the WBC it was sometimes worse than specified. Most parameters were not strictly linear on dilution but only for the MCV and the MCH was the deviation from linearity sufficient to be of practical importance. Carryover was satisfactory. Results were generally comparable with those of a Coulter Counter Model S Plus IV. Estimates on all parameters were satisfactory on blood samples stored up to 24 h at either 4 degrees C or room temperature; beyond 24 h inaccuracy was seen particularly in the WBC, platelet count and MCV. Throughput was 60 to 70 samples/h in the whole-blood mode. Start-up and shut-down times were acceptably short. The instrument was assessed as acceptable and clinically useful, although reliability was somewhat less than expectations.

Unique pattern of HTLV-III (AIDS-related) antigen recognition by sera from African children in Uganda (1972)

Of 75 sera collected in the West Nile district of Uganda over a 1-year period between 1972 and 1973, 50 (66%) had antibody reactivity to human T-cell lymphotropic virus subgroup III (HTLV-III) at low titer levels. Sera were initially screened by HTLV-III enzyme linked immunosorbent assay and sera with values less than normal mean + 2 SD were removed from testing. The remaining sera were tested for positivity by an amplified Western blotting procedure which incorporated a three-layer immunoperoxidase procedure. Immunoglobulin reactive with HTLV-III Mr 24,000, 41,000, and 76,000 proteins were present in nearly all positive sera. The antibody status of this group was unlike any normal or acquired immunodeficiency syndrome-risk group previously tested. The high prevalence and relatively low titers suggest the detection as early as 1972 of a relative or predecessor of HTLV-III or of HTLV-III itself but existing in a population acclimated to its presence. It further suggests a likely African origin of HTLV-III.

Expression of red cell antigens by K562 human leukemia cells before and after induction of hemoglobin synthesis by hemin

We studied the red cell antigens present on K562 human leukemia cells before and after induction of hemoglobin synthesis by hemin. The fetal antigens i, IF, and IT were detected on uninduced cells. While expression of both i and IT antigens increased after hemin induction, expression of IT was closely related to fetal hemoglobin synthesis as determined in experiments in which the induction was reversed. The EnaFR, NVg, and T antigens of glycophorin A were also present on uninduced cells. In contrast, the M and Pra antigens of glycophorin A, the Kell system antigens, and the P1 antigen became detectable only after hemin induction. Antigens of other major red cell systems were not detected.

A beta-globin gene, inactive in the K562 leukemic cell, functions normally in a heterologous expression system

The K562 human leukemia cell is an erythroid-like cell that may serve as a model for the study of globin gene expression in transcriptionally active human erythroid cells. K562 cells express all globin genes with the exception of that for beta-globin; failure to produce beta-globin could result from an acquired mutation in each of the beta-globin genes or from an alteration in the regulatory factor environment of the beta-globin gene. To uncover a possible acquired mutation, restriction endonuclease analysis of genomic K562 DNA and expression studies of a cloned K562 beta-globin gene were carried out. Restriction endonuclease analysis revealed no structural alteration of the K562 beta-globin genes. Analysis of the polymorphic Ava II site in intervening sequence 2 of the beta-globin gene showed that K562 cells contain two different beta-globin alleles, both of which are inactive. A K562 beta-globin gene was cloned, ligated into the expression vector pLTN3B, and introduced into COS cells. Transcripts were analyzed by RNA blot, dot blot, S1 nuclease mapping, and primer extension assay. The cloned K562 beta-globin gene was transcribed in COS cells as efficiently as a normal beta-globin gene introduced into COS cells; the mRNA was 10 S and polyadenylylated; the 5' and 3' termini and the processing of transcripts were identical to that of mRNA transcribed from a normal gene. Based on these data we suggest that the absence of beta-globin gene expression results not from an alteration in the beta-globin gene, but from a quantitative or qualitative alteration in a trans-acting factor important in beta-globin gene expression.

Control of oxygen affinity of hemoglobin in K562 cells induced by hemin

The oxygen affinity of hemoglobin in K562 cells induced by hemin and the relationship between levels of 2,3-diphosphoglycerate (2,3-DPG) and hemoglobin have been investigated. Absorption spectra of induced cells indicate that the hemoglobin is oxygenated; oxygen dissociation curves are symmetric, with a P50 of 20 +/- 0.9 mm Hg, Hill coefficient of 2.5, and a normal temperature dependence. The intracellular pH measured by phosphorus 31 nuclear magnetic resonance (NMR) was 7.3. The amount of 2,3-DPG was determined by an enzymatic method and by 31P NMR. The level of 2,3-DPG in uninduced K562 cells, containing 0.5 pg of hemoglobin per cell, was low (5 +/- 0.5 mumole/10(8) cells), but increased to 64 +/- 5 mumole/10(8) cells upon induction of hemoglobin accumulation (to a final level of 20 pg hemoglobin/cell). For several experiments, there was a closely coordinated relationship between 2,3-DPG and hemoglobin levels, at about 1:1 stoichiometry of the two molecules. The time course of induction of hemoglobin, and of 2,3-DPG levels, are very similar; both processes are reversible. These data suggest that induction of hemoglobin synthesis in K562 cells by hemin results in hemoglobin-containing cells with normal oxygenation properties and that 2,3-DPG and hemoglobin levels are coordinately controlled in these cells. Elucidation of the mechanism of this effect should be of importance in understanding the erythroid-like differentiation of these cells.

Inducible transcription of five globin genes in K562 human leukemia cells

We studied the abundance and structure of globin mRNAs present in K562 cells both before and after induction of hemoglobin synthesis by hemin. In vitro translation of poly(A)+ RNA from K562 cells generated protein products corresponding to alpha, A gamma-, G gamma-, epsilon-, and zeta-globin mRNAs. Individual globin mRNAs increased 1.5- to 3-fold after induction. Similar results were obtained by measuring steady-state mRNA concentrations of induced and uninduced cells by using S1 nuclease mapping. Globin gene transcripts were correctly initiated and processed. In addition, S1 nuclease analysis revealed the presence of delta-globin mRNA in both control and induced cells. A small percentage of delta-globin transcripts appeared to be initiated upstream from the normal initiation site. beta-Globin mRNA was not detected in any studies. The results (i) suggest that hemin induction of K562 cells is mediated at a transcriptional level and (ii) reveal the dissociation of delta- and beta-globin gene expression in K562 cells compared with normal erythroid cells.