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S Bottomley

Publications and source records attributed to S Bottomley.

At least 19 recordsLinked to original sources
PubMed2000

Bioinformatics.

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Journal Article↗
PubMed2000

Development of a ubiquitin transfer assay for high throughput screening by fluorescence resonance energy transfer.

An assay based on fluorescence resonance energy transfer (FRET) has been developed to screen for ubiquitination inhibitors. The assay measures the transfer of ubiquitin from Ubc4 to HECT protein Rsc 1083. Secondary reagents (streptavidin and antibody to glutathione-S-transferase [GST]), pre-labeled with fluorophores (europium chelate, Eu(3+), and allophycocyanin [APC]), are noncovalently attached via tags (biotin and GST) to the reactants (ubiquitin and Rsc). When Rsc is ubiquitinated, Eu(3+) and APC are brought into close proximity, permitting energy transfer between the two fluorescent labels. FRET was measured as time-resolved fluorescence at the emission wavelength of APC, almost entirely free of nonspecific fluorescence from Eu(3+) and APC. The FRET assay generated a lower ratio of signal to background (8 vs. 31) than an assay for the same ubiquitination step that was developed as a dissociation-enhanced lanthanide fluoroimmunoassay (DELFIA). However, compared to the DELFIA method, use of FRET resulted in higher precision (4% vs. 11% intraplate coefficient of variation). Quenching of fluorescence was minimal when compounds were screened at 10 microg/ml using FRET. Employing a quick and simple homogeneous method, the FRET assay for ubiquitin transfer is ideally suited for high throughput screening.

Dimethyl Sulfoxide↗
PubMed1999

Bioinformatics.

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Journal Article↗
PubMed1999

Bioinformatics.

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Journal Article↗
PubMed1999

Comparing patient, parent, and staff descriptions of fatigue in pediatric oncology patients.

Fatigue in children and adolescents with cancer is a disruptive symptom meriting clinical intervention by nurses, but has eluded definition, measurement, and intervention. Fatigue in these patients exists within a greater context of illness, treatment, and child and family development. Any effort to define, measure, and intervene with fatigue needs to take into consideration the major components of these children and adolescents' treatment context. The purpose of this descriptive study was to learn from three perspectives (patient, parent, and staff) how fatigue is identified and defined in 7- to 12-year-old children and in 13- to 18-year-old adolescents with cancer, and what factors contribute to or alleviate this fatigue. To elicit this information, separate focus groups were conducted with patients, parents, and staff at two pediatric oncology centers. Resulting interview data were analyzed using pragmatic and semantic content analysis techniques and the Wilson concept analysis process. Findings clearly indicated that children, adolescents, parents, and staff define patient fatigue differently. The conceptual definition from the child data emphasizes the physical sensation of the fatigue; alternating and at times merging physical and mental tiredness are emphasized in the adolescent's definition. Parents and staff view themselves as responsible for alleviating patient fatigue; patients viewed rest and distraction as their primary sources of improving fatigue. The conceptual definitions of fatigue as rendered by our three groups of participants can assist pediatric oncology patients, their parents, and staff in identifying fatigue. Factors identified by these participants as contributing or alleviating fatigue could be the basis for future interventions designed to reduce fatigue in pediatric oncology patients.

Adolescent↗
PubMed1999

Providing quality care in childhood cancer survivorship: learning from the past, looking to the future.

As we move into the 21st century, we are faced with an increasing number of childhood cancer survivors who are living into their middle adult years and beyond. Providing appropriate, comprehensive follow-up care is a challenge for health care providers and one that can be met by developing quality follow-up programs for all childhood cancer survivors. The focus of these programs should be to educate these survivors on strategies to maximize their health and well being. This article discusses the evolution of survivor clinics, strategies for developing a quality program, and the role of nursing in the care of childhood cancer survivors.

Child↗
PubMed1997

Development of two instruments examining stress and adjustment in children with cancer.

The childhood cancer literature provides limited understanding of the school-age child's perception of cancer stressors and factors that contribute to adjustment in the midst of these stressors. This study evaluated the reliability and validity of two questionnaires: the Childhood Cancer Stressors Inventory (CCSI) and the Children's Adjustment to Cancer Index (CACI). The following steps were involved in the instrument development process: item development, face and content validation, internal consistency reliability, and construct validity. Questions for both instruments were developed from the literature and experience of the principal investigator. A panel of five expert pediatric oncology nurses was asked to evaluate the content validity of both instruments. All the experts rated every item a 4-5 using the content validity index, indicating that each item measured the concept addressed by the scale. Seventy-five children with cancer were asked to complete the two questionnaires and parents completed a demographic data sheet that included eight questions about the child's school attendance, performance, number of friends, and activities. Children were 7 to 13 years of age; 64% were diagnosed with a leukemia/ lymphoma, and 36% had a solid tumor. Internal coefficient reliability for the total CCSI was .82, and .91 for the CACI. The CCSI correlated negatively with the adjustment scale (r = -.63, P = 000). The number of days missed from school correlated positively with the CCSI and negatively with the CACI. Children who missed more school perceived more cancer stressors and had a lower adjustment rating. Children with lower adjustment ratings on the CACI also had fewer friends (t = 3.4(72), P = .001). Scores on both instruments demonstrated expected relationships with measures hypothesized to covary with the dimensions assessed by the new instruments. Adjustment issues for children with cancer have been difficult to assess because of the lack of appropriate instruments. These study findings indicate that the two new instruments can help to measure the child's perceptions of the cancer experience.

Adaptation, Psychological↗
PubMed1990

Absence of insulin-receptor downregulation in hepatocytes from hyperinsulinemic rats.

Insulin-induced downregulation of the insulin receptor occurs in conditions associated with high extracellular concentrations of insulin. This paper describes the effect of experimental hyperinsulinemia on insulin binding to isolated hepatocytes. In vivo experimental hyperinsulinemia was produced in rats by subcutaneous injection of long-acting insulin at low (10 mU.g-1.day-1), medium (up to 25 mU.g-1.day-1), and high (up to 50 mU.g-1.day-1) doses over 1 or 2 wk. Insulin-stimulated lipogenesis was measured to determine the efficacy of the experimentally produced hyperinsulinemia. The results showed that 1) insulin-induced downregulation, determined by insulin binding, was not present in hepatocytes from any of the hyperinsulinemic rats; 2) insulin binding was increased in hepatocytes from 1- and 2-wk high-dose hyperinsulinemic rats compared with 1-wk sucrose-control (P less than 0.05), 2-wk sucrose-control (P less than 0.01), and normal rats (P less than 0.01); 3) increased binding may have been due to an increase in the number of low-affinity receptors; 4) insulin's effect on lipogenesis (i.e., insulin-stimulated lipogenesis minus the basal value) was increased in either 1-wk (P less than 0.001) or 2-wk (P less than 0.001) high-dose insulin-treated rats compared with either normal or 2-wk sucrose-control rats; 5) insulin's effect on hepatocyte lipogenesis in sucrose-control (P less than 0.025) and in all other insulin-treated (P less than 0.008 or P less than 0.05 for 2-wk medium dose) rats was greater than insulin's effect in normal hepatocytes. The reasons for the absence of downregulation are not clear, but rapid receptor recycling, rapid degradation, and upregulation are listed as possibilities.

Animals↗
PubMed1988

HPLC separation of corticosterone metabolites and its use in following corticosterone metabolism and transport in the isolated rat hepatocyte.

Incubating isolated rat hepatocytes with tritium labelled and unlabelled corticosterone at 37 degrees C resulted in the rapid appearance of at least nine corticosterone metabolites. A quick, relatively easy, and quantitative high performance liquid chromatographic (HPLC) method was used to separate these metabolites and follow their rate of appearance both intra- and extracellularly. We found different intra- and extracellular amounts of each metabolite at a particular time and this suggested that some metabolites were more available for transport than others.

Animals↗
PubMed1987

Rat hepatocyte lipogenesis and insulin-stimulated lipogenesis: comparison of metabolite effects and methods of measurement.

This study compared the effects of certain metabolites (either singly or in various combinations) and the methods of measuring lipogenesis (using either 14C-acetate or 3H2O incorporation into lipids) on total lipid synthesis and insulin-stimulated total lipid synthesis in the isolated rat hepatocyte. There were quantitative and qualitative differences between 14C-acetate and 3H2O incorporation into lipids; metabolites acutely affected both lipogenesis and insulin-stimulated lipogenesis with either isotope; and insulin's effect on lipogenesis was greater when measured by 14C-acetate incorporation. It is suggested that a particular choice of incubation media and isotope may inadvertently bias a study of insulin-stimulated lipogenesis and that metabolite supply plays a major role in regulating insulin-stimulated lipogenesis.

Amino Acids↗
PubMed1984

Factors affecting fasting serum C-peptide levels in Micronesians: comparison with a Caucasoid population.

Fasting serum C-peptide immunoreactivity was determined on Nauruans, a Micronesian population with a high prevalence of diabetes. In Micronesian subjects neither age nor gender had a significant effect on fasting serum C-peptide. In non-diabetic subjects, as has been shown previously for Caucasiod subjects, both obesity and fasting plasma glucose levels were determinants of fasting serum C-peptide. Obesity was the major determinant. Taken overall, mean fasting serum C-peptide increased then possibly fell in subjects grouped by increasing 2-h post-glucose plasma glucose levels. Mean fasting serum C-peptide in newly-diagnosed diabetic subjects was greater than that in non-diabetic subjects with a similar degree of obesity, supporting the concept that the transition to diabetes may be associated with an increase in insulin resistance. The data for non-diabetic subjects were compared with serum C-peptide measured in the same laboratory on samples from a Caucasoid population in Busselton, Western Australia. There was no difference in fasting serum C-peptide level between Micronesian and Caucasoid subjects approximately matched for obesity and fasting plasma glucose levels.

Adult↗