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Biomedical subjects

C Stephenson

Publications and source records attributed to C Stephenson.

At least 37 records · Page 2Linked to original sources
PubMed1992

Prescribing and dispensing of insulin: margins for error?

To investigate recent anecdotal reports of incorrect insulin dispensing, we compared retail pharmacists' and doctors' understanding of commonly used insulin brands. Eighty pharmacists, 29 general practitioners (GPs), and 31 junior hospital doctors were interviewed and completed a questionnaire concerning the duration of action and formulation of 17 insulins. Views on dispensing of alternative insulins were sought from the pharmacists. Fifteen insulin pairs in two columns, 'insulin prescribed' and 'dispense instead', were presented and pharmacists and doctors asked if substitution was appropriate. Mixtard, Penmix and Actrapid were the best understood insulins, Insulatard, Humulin Zn and Protaphane the worst. Both GPs (p = 0.014) and hospital doctors (p < 0.001) scored better than pharmacists. No pharmacist stated that they would routinely dispense alternative insulin, 27 out of 80 not even in an emergency, though 37 were prepared to do so in such a situation after checking, usually with a doctor or in the relevant literature. Sixteen pharmacists, 24 GPs, and all 31 hospital doctors completed the section on insulin pairs but accuracy at identifying appropriate substitutions was poor. These findings coupled with confusing insulin nomenclature may lead to dangerous dispensing errors.

Dosage Forms↗
PubMed1991

Normal expression of thymidine kinase and O6-methylguanine-DNA methyltransferase in cultured fibroblasts from individuals with hereditary galactokinase deficiency.

Expression of the enzymes galactokinase, thymidine kinase, and O6-methylguanine-DNA methyltransferase is occasionally coordinately regulated in human cell lines. We have measured the activities of these three enzymes in extracts of fibroblasts from individuals with hereditary galactokinase deficiency. These cells do not express measurable galactokinase activity. The levels of O6-methylguanine-DNA methyltransferase were in the normal range in cells from three galactokinase-deficient individuals. The activity of thymidine kinase in the affected cells was in the normal range for two of the three individuals. The reduced thymidine kinase activity in the third individual reflected the extremely poor growth of the cells in culture. Immortalization of one galactokinase-deficient cell line resulted in loss of O6-methylguanine-DNA methyltransferase activity, but the galactokinase and thymidine kinase levels remained unchanged. The data indicate that the loss of galactokinase activity in these individuals is the consequence of an alteration of gene expression which does not involve coordinate silencing with the thymidine kinase and methyltransferase loci.

Cell Line↗
PubMed1991

The concept of hope revisited for nursing.

The development of nursing knowledge and interventions involve understanding human responses and needs. The human response of hope was identified as a concept in need of further clarification. The purpose of this paper was to review definitions and contextual usage of the word 'hope' from the literature and answer the conceptual question 'What is hope?' Literature from theology, philosophy, psychology and nursing was reviewed for contextual usage of the word 'hope'. In the literature, hope was viewed as part of human development, a process, a theory and a source of meaning in life. In addition, antecedents, attributes and outcomes of hope were identified from the literature that contributed to a clearer understanding of the concept.

Affect↗
PubMed1990

Coregulation of the human O6-methylguanine-DNA methyltransferase with two unrelated genes that are closely linked.

The loss of expression of the enzyme O6-methylguanine-DNA methyltransferase (the Mex- phenotype), which often results from cellular transformation, confers hypersensitivity to alkylating agents. We have observed two unrelated examples in which human cell lines have undergone a spontaneous alteration in their Mex phenotype during propagation in vitro. The change was reversible and was not the result of mutation. In both cases a loss of methyltransferase expression was accompanied by a simultaneous loss of expression of two metabolically unrelated enzymes: thymidine kinase and galactokinase. "Reversion" to methyltransferase expression was accompanied by simultaneous reexpression of both kinase activities. A third example of this coordinate gene regulation was seen with the Burkitt's lymphoma cell line Raji which expresses methyltransferase, thymidine kinase, and galactokinase at high levels. A thymidine kinase- Raji cell line derived by bromodeoxyuridine mutagenesis that is also Mex- was found to be galactokinase-. It appears that methyltransferase expression may in some instances be coordinately regulated with the tk and glk loci which are closely linked on human chromosome 17.

Adenosine Triphosphatases↗
PubMed1990

Intralesional interferon gamma treatment for keloids and hypertrophic scars.

Keloids and hypertrophic scars are characterized by excessive collagen formation. Interferon gamma is a lymphokine that can down-regulate collagen synthesis in vitro and in vivo and, therefore, has potential therapeutic benefit in the management of abnormal scars. Intralesional scar injections of interferon gamma were performed to determine the tolerance toxicity and to obtain preliminary evidence for the efficacy of this treatment in the management of hypertropic and keloid lesions. All scars decreased in linear dimensions and flattened out. Five of 10 scars studied decreased at least 50% in linear dimensions. Interferon gamma can safely be administered intralesionally once per week up to a dosage of 0.05 mg for 10 weeks with no serious toxic effects. The commonest reported side effect was a mild headache.

Adult↗
PubMed1989

Selective binding to DNA base pair mismatches by proteins from human cells.

Using the technique of delayed oligonucleotide migration through polyacrylamide gels, we have demonstrated that cell-free extracts of the human Burkitt's lymphoma cell line Raji contain proteins which can recognize and bind to mismatched single base pairs in short fragments of DNA. One of these binding proteins resembles an activity previously reported in HeLa cells (Jiricny, J., Hughes, M., Corman, N., and Rudkin, B. B. (1988) Proc. Natl. Acad. Sci. U. S. A. 85, 8860-8864) and recognizes DNA containing G.T mismatches. Extracts of Raji cells contain an additional activity which recognizes A.C, T.C, or T.T mismatches in DNA. This second binding protein can be distinguished from the G.T binding activity by its size, substrate specificity, and its fractionation properties. In addition to Raji cells, the new mismatch binding protein is present in extracts of human lymphoblastoid cell lines from a normal individual and a xeroderma pigmentosum patient as well as the SV40-transformed human fibroblast cell line MRC5V1. It seems likely that this novel activity is involved in a broad specificity DNA repair pathway for the correction of single base mismatches in human cells.

Base Composition↗
PubMed1988

The contribution of O6-methylguanine and methylphosphotriesters to the cytotoxicity of alkylating agents in mammalian cells.

A modified Escherichia coli ada+ gene which encodes methyltransferase active on O6-methylguanine, but not methylphosphotriester residues in DNA has been introduced by transfection into Chinese hamster ovary cells. Expression of the altered Ada protein in these cells conferred resistance to methylating agents. However, in two independently derived cell lines, the relation between enzyme activity and the degree of protection was not quantitative. The molecular nature of the Ada protein fragment produced differed between the two cell lines. In addition, cell lines exhibiting increased resistance to N-methyl-N'-nitro-N-nitrosoguanidine have been derived from a cell line expressing the Ada protein methylphosphotriester repair function. The resistant cell lines expressed elevated levels of methylphosphotriester repair protein. However, this enhanced DNA repair activity was not responsible for the observed resistance.

Alkylating Agents↗
PubMed1988

Clinicopathological significance of immunoreactive beta-hCG production by bladder cancer.

Immunocytochemical screening of bladder tumors with an antibody to beta-human chorionic gonadotrophin (hCG) demonstrates a correlation with malignant behavior in that 0 of 20 G1M0, 5 of 20 G3M0, and 11 of 20 G2/3M + showed strong staining, while only 2/20 G3 Ca prostate and 0/18 renal cell carcinoma showed weak staining. There was a suggestion that hCG positive bladder cancer responded less well to chemotherapy (1 of 12 hCG positive and 6 of 13 hCG negative patients achieved a complete or partial response) and also patients whose tumors showed strong hCG staining did less well after radiotherapy, though paradoxically patients showing only occasional stained cells did better than patients whose tumor showed no staining. The possible significance of these observations in relation to recent observations on the mechanisms of trophoblast escape from immune surveillance is discussed.

Biomarkers, Tumor↗
PubMed1986

Factors influencing acquired subgottic stenosis in infants.

A prospective study of factors that might contribute to the development of acquired subglottic stenosis was undertaken in newborn infants with endotracheal tubes in place for 7 days or more. Duration of intubation, the number of endotracheal tubes inserted, the duration of mechanical ventilation, the presence of post-extubation stridor, and the size of the endotracheal tube in relation to gestational age significantly correlated with the development of subglottic stenosis. Patients at risk for significant subglottic stenosis were those with post-extubation stridor and those with tubes in place for 25 days or longer. On the basis of these findings, it is recommended that endotracheal tubes be chosen such that the ratio of nominal tube size divided by the patient's gestational age in weeks is less than 0.1.

Birth Weight↗
PubMed1983

Reconstruction of the eyelid using a myocutaneous island flap.

Traditionally, skin flaps have been based upon a contiguous skin pedicle. Recently the concept has re-emerged that the important blood supply frequently lies subjacent to the flap. A temporally based island flap composed of skin and orbicularis muscle, nourished only by its subjacent pedicle, has been successfully used in the reconstruction of 91 eyelid defects.

Aged↗
PubMed1983

Visits by elementary school children to the school nurse.

Various factors seem to influence health seeking and illness behavior in childhood, among which are early socialization, modeling behavior in adults, the labeling of illness and psychological distress. The characteristics of a group of elementary school children who visited the nurse's office were observed and descriptive data were obtained on 551 students during a six-month period. Correlation analysis of the data was made. The conclusion of the study supported the following ideas: 1) health seeking and illness behavior was a learned process; 2) there was no differences noted in the frequency of visitation by boys or girls; and 3) recurrent health problems contributed to the frequency of visitation. The role of the school nurse in assessing potential physical and or psychological problems was affirmed.

Age Factors↗
PubMed1978

Small nuclear RNAs: an association with condensed chromatin in amoebae.

For the purpose of studying the relationship of small nuclear RNAs (snRNAs) to chromatin, we studied the effect of the chromatin-binding agent actinomycin D (AMD) on the nuclei of amoebae. By electron microscopy we noted that when mitotic cells were placed in AMD their chromatin was highly condensed 3 h later. This contrasts strikingly with the situation in untreated cells, in which the chromatin at the same time is largely decondensed. After arranging, by nuclear transplantation of labelled nuclei into unlabelled cytoplasm, for the only labelled molecules in the cell to be 3H-snRNAs, we noted that in such cells similarly treated with AMD the labelled material was clustered in a form quite similar to that of the chromatin in 3-h post-division, AMD-treated cells. In untreated cells the 3H-snRNAs were distributed essentially uniformly throughout the nucleus. These observations, together with earlier findings that snRNAs associate with chromosomes during mitosis, lead us to conclude that snRNAs have a particular affinity for condensed chromatin.

Amoeba↗