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Biomedical subjects

C M Burns

Publications and source records attributed to C M Burns.

At least 19 recordsLinked to original sources
PubMed2005

Knowledge of treatment intent among patients with advanced cancer: a longitudinal study.

Increasingly, patients with cancer wish to be more fully informed about their disease, treatment and prognosis, and to participate in decision making. The objective of this study was to assess knowledge of diagnosis and goals of treatment among patients with advanced cancer, and also to assess whether this knowledge changed over time. A cohort of 181 subjects with advanced cancer receiving palliative therapies were interviewed at entry and again 12 weeks later. Knowledge of disease diagnosis, treatment intent, and the main sources of information were determined. Twenty per cent of subjects considered their illness to be non-life threatening, and 46% correctly perceived treatment intent as non-curative; 29% believed the intent of treatment was cure. Subjects resident in rural areas were more likely to misunderstand the goal of their treatment. Treatment modality was significantly associated with knowledge of treatment intent, and subjects in the last 6 months of life had clearer understanding that treatment intent was non-curative. Many patients with advanced cancer do not understand the goals of treatment. Excessive optimism may lead to impaired decision making. Further empirical research into information transfer and predictors of accurate patient understanding would assist clinicians in their discussions of prognosis and potential treatment outcomes with patients.

Aged↗
PubMed2004

Food cost and availability in a rural setting in Australia.

INTRODUCTION: The burden of chronic diseases is rapidly increasing worldwide. In Australia rural populations have a greater burden of disease. Chronic diseases are largely preventable with diet as a key risk factor. With respect to diet-related chronic disease, dietary risk may be due to poor food access, namely, poor availability and/or the high cost of healthy food. It is likely that poor food access is an issue in rural areas. OBJECTIVE: To assess food access in rural south-west (SW) Victoria, Australia. METHODS: A total of 53 supermarkets and grocery stores in 42 towns participated in a survey of food cost and availability in the rural area of SW Victoria. The survey assessed availability and cost of a Healthy Food Access Basket (HFAB) which was designed to meet the nutritional needs of a family of 6 for 2 weeks. RESULTS: Seventy-two percent of the eligible shops in SW Victoria were surveyed. The study found that the complete HFAB was significantly more likely to be available in a town with a chain-owned store (p <0.00). The complete HFAB was less likely to be available from an independently owned store in a town with only one grocery shop (p <0.004). The average cost of the HFAB across SW Victoria was AU380.30 dollars +/- 25.10 dollars (mean +/- SD). There was a mean range in difference of cost of the HFAB of 36.92 dollars. In particular, high variability was found in the cost of fruits and vegetables. CONCLUSIONS: Cost and availability of healthy food may be compromised in rural areas. IMPLICATIONS: Improvements in food access in rural areas could reduce the high burden of disease suffered by rural communities.

Journal Article↗
PubMed2004

Evaluation of IS900-PCR assay for detection of Mycobacterium avium subspecies Paratuberculosis infection in cattle using quarter milk and bulk tank milk samples.

A study was conducted to evaluate sensitivity, specificity, and predictive value of IS900-PCR assay for detection of Mycobacterium avium subspecies paratuberculosis in pooled quarter milk and bulk tank milk. Feces, blood and pooled quarter milk from 1493 lactating cattle on 29 herds were analyzed. Bulk tank milk (n = 29 bulk tanks) samples were also examined. Culture analysis revealed that 10.9%, 2.8%, and 20.6% of fecal, pooled quarter milk samples and bulk tanks were positive for M. avium subsp. paratuberculosis, respectively. While 13.5% and 27.5% of pooled quarter milk samples and bulk tanks were positive by IS900 PCR assay, respectively. Moderate to high antibody titers for M. avium subsp. paratuberculosis were detected in 223 of 1493 (14.4%) cows. Cows positive on fecal culture were taken as true positives relative to which the IS900 PCR assay was evaluated. The sensitivity and predictive value of KELA, pooled quarter milk culture, and IS900 PCR assay increased with lactation age. While the specificity of the tests decreased with increase in lactation age. Overall, the IS900 PCR assay using pooled quarter milk samples had a sensitivity, specificity and predictive value of 0.87, 0.95 and 0.71, respectively. The IS900 PCR assay using bulk tank milk had poor sensitivity (0.21), specificity (0.5) and predictive value (0.6). Pooled quarter milk culture analysis had a very low sensitivity (0.17). The kinetics ELISA had lower sensitivity (0.59), specificity (0.90) and predictive value (0.43) as compared to the IS900 PCR assay using pooled quarter milk samples. Results from our study suggest that IS900 PCR assay using bulk tank milk may not be useful for screening herds with M. avium subsp. paratuberculosis infected animals. In conclusion, use of IS900 PCR assay for cows in 2(nd) lactation and higher, using aseptically collected pooled quarter milk samples, can be a useful tool for screening and monitoring lactating cattle in herds with M. avium subsp. paratuberculosis infection.

Animals↗
PubMed2001

The nucleoid-associated protein StpA binds curved DNA, has a greater DNA-binding affinity than H-NS and is present in significant levels in hns mutants.

The StpA protein is closely related to H-NS, the well-characterised global regulator of gene expression which is a major component of eubacterial chromatin. Despite sharing a very high degree of sequence identify and having biochemical properties in common with H-NS, the physiological function of StpA remains unknown. We show that StpA exhibits similar DNA-binding activities to H-NS. Although both display a strong preference for binding to curved DNA, StpA binds DNA with a four-fold higher affinity than H-NS, with K(d)s of 0.7 microM and 2.8 microM, respectively. It has previously been reported that expression of stpA is derepressed in an hns mutant. We have quantified the amount of StpA protein produced under this condition and find it to be only one-tenth the level of H-NS protein in wild-type cells. Our findings explain why the presence of StpA does not compensate for the lack of H-NS in an hns mutant, and why the characteristic pleiotropic hns mutant phenotype is observed.

Bacterial Proteins↗
PubMed2001

Modeling a medical environment: an ontology for integrated medical informatics design.

Modern medical environments have seen an increase in technological complexity and pressures of handling more patients with fewer resources, resulting in higher demands on medical practitioners. Medical informatics designers will have to focus on the problem of organizing medical information more effectively to enable practitioners to cope with these challenges. This article addresses this research problem for the particular area of medical problem solving in patient care. First, we describe a traditional modeling approach for medical reasoning used as a basis for developing some decision support systems. We argue these models may be faithful to what is known about biomedical knowledge, but they have limitations for human problem solving, especially in unanticipated situations. Second, we present an ontological framework, known as the abstraction hierarchy (Rasmussen, IEEE Trans. Man. Cybernetics 15 (1985) 234-243), for integrating patient representations that are faithful to existing biomedical knowledge and that are consistent with what is known about human problem solving. Through an example of a critical event in the operating room, we reveal how this framework can support medical problem solving in unanticipated situations. Third, we show how to use these representations as a frame of reference for mapping medical roles, responsibilities, sensors, and controls in an operating room context. Finally, we provide some insight for medical informatics designers in using this framework to design novel training programs and human-computer displays.

Decision Support Techniques↗
PubMed2001

The relationship between quality of life and perceived body weight and dieting history in Dutch men and women.

OBJECTIVES: (1) To study the relationship between quality of life (QoL) and measured and perceived weight and dieting history in Dutch men and women; (2) to assess the effect of weight loss over a 5 y period on QoL. DESIGN: A cross-sectional study, in a sub-sample longitudinal over 5 y. SUBJECTS: A total of 2155 men and 2446 women, aged 20-59 and recruited from the general population from three towns in The Netherlands. MEASUREMENTS: Body weight, height, self-administered questionnaire including questions concerning demographic variables and weight loss practices as part of the Dutch Monitoring project on Risk Factors for Chronic Disease (MORGEN). The Rand-36 questionnaire was used as the QoL measure. RESULTS: In men, measured overweight (body mass index, BMI>25 kg/m(2)) was not associated with any dimension of QoL after adjustment for age, educational level and perceived overweight. Perceived overweight was related to reduced scores for general health and vitality. This relationship was independent of measured obesity. A history of repeated weight loss was associated with reduced scores for role functioning due to both physical and emotional problems. In women, measured overweight was significantly associated with lower scores for five out of eight QoL dimensions and perceived overweight with three: general health, vitality and physical functioning. A history of frequent weight loss was related to significantly reduced scores in six dimensions. However, only with history of frequent weight loss, and uniquely in women, was there a significant reduction in scores on mental health and limited emotional role functioning. Measured and perceived overweight and frequent weight loss were all related to reduced scores for physical functioning. Longitudinal data indicate that in older women weight gain of 10% body weight or more was associated with a significant deterioration in QoL. CONCLUSIONS: When looking at measures of QoL in relation to overweight it is important to separate the effects of perception of weight status and history of weight loss. We observed that the latter two factors were associated with reduced scores on several dimensions of QoL, particularly in women. These associations were observed to be independent of body weight.

Adult↗
PubMed2001

Penetrating neck injuries: analysis of experience from a Canadian trauma centre.

OBJECTIVE: To study the demographics and treatment outcome of penetrating neck injuries presenting to a major trauma centre in order to develop a treatment protocol. DESIGN: A case review. SETTING: A trauma centre at a tertiary care institution. PATIENTS: One hundred and thirty consecutive patients who had 134 neck wounds penetrating the platysma and presented to the trauma service between 1979 and 1997. INTERVENTION: Surgical exploration or observation alone. MAIN OUTCOME MEASURES: The location of injury, patient management, number of significant injuries, duration of hospital stay and outcome. RESULTS: Injuries were caused by stab wounds in 124 patients (95%) and gunshot wounds in 6 (5%). The location of injury was zone I (lower neck) in 20 cases (15%), zone II (midportion of the neck) in 108 (81%) and zone III (upper neck) in 5 (4%). The location was not recorded in 1 case. Fifty patients were managed by observation alone and 80 were managed surgically. Neck exploration in 48 asymptomatic patients was negative in 32 (67%). Significant injuries, including major vascular (12), nerve (13) and aerodigestive tract (19) injuries, were identified in 34 patients. Two of the 130 patients (1.5%) died of major vascular injuries. Seventy-six percent of significant injuries, including all zone II major vascular injuries, were symptomatic on presentation. The mean (and standard deviation) hospital stay for asymptomatic patients treated with observation alone and surgical exploration was similar (3.5 [6.02] versus 4.3 [5.46] days respectively, p = 0.575). Long-term disability, all neurologic in nature, was documented in 3 patients managed by observation alone and 6 patients managed by surgical exploration. CONCLUSIONS: Penetrating neck trauma, in particular stab wounds to zone II in asymptomatic patients, is associated with low morbidity and mortality. A selective management protocol with investigations directed by symptoms is the most appropriate approach for the patient population and resource base in this setting.

Adolescent↗
PubMed2000

Determination of the free-energy change for repair of a DNA phosphodiester bond.

The repair of phosphodiester bonds in nicked DNA is catalyzed by DNA ligases. Ligation is coupled to cleavage of a phosphoanhydride bond in a nucleotide cofactor resulting in a thermodynamically favorable process. A free energy value for phosphodiester bond formation was calculated using the reversibility of the T4 DNA ligase reaction. The relative number of DNA nicks to phosphodiester bonds in a circular plasmid DNA, formed during this reaction at fixed concentrations of ATP to AMP and PP(i), was quantified. At 25 degrees C, pH 7, the equilibrium constant (K(eq)) for the ligation reaction is 3.89 x 10(4) m. This value corresponds to a standard free energy (DeltaG degrees ') of -6.3 kcal mol(-1). By subtracting the known energy contribution due to hydrolysis of ATP to AMP and PP(i), DeltaG degrees ' for the hydrolysis of a DNA phosphodiester bond is -5.3 kcal mol(-1).

Adenosine Monophosphate↗
PubMed2000

A participant-observer study of ergonomics in engineering design: how constraints drive design process.

Too often, ergonomics is relegated to being a "post-design" evaluation, leaving ergonomists little opportunity to make significant and important design changes. One way to start attacking this problem is to study the process of design and, in particular, ergonomics in design. This article describes the findings from a four-month long participant-observer study of the relationship between ergonomics and engineering design. The study was conducted in the context of a large, interdisciplinary project consisting of design of a control room for a nuclear power plant. It was observed that designers and ergonomists must negotiate through a changing web of constraints from many sources. The impact that these constraints had on the course of the design was documented. A model is developed based on the abstraction hierarchy (Rasmussen, 1985, IEEE Trans. Systems Man Cybernet. SMC-15, 234-243; 1990, Int. J. Ind. Ergon. 5, 5-16) which shows the interaction of conflicting goals as ergonomists and other designers attempt to solve a complex design problem. This model leads to several insights: (1) locally optimal ergonomic designs may not be globally optimal, (2) ergonomists can improve their solutions by understanding the goals of other designers, and (3) future tools to aid ergonomists must be compatible with the constraint-rich environments in which they work.

Ergonomics↗
PubMed2000

Putting it all together: improving display integration in ecological displays.

Computer displays are being designed for increasingly larger industrial systems. As the application domain scales up, maintaining integration across different kinds of views becomes more challenging. This paper presents the results of a study of three different approaches to integration based on the spatial and temporal proximity of related information objects. The domain used for evaluation was a simulation of an industry-scale conventional power plant. All three displays were ecological displays developed using an abstraction hierarchy analysis. Views were integrated in a high-space/low-time, low-space/high-time, and high-space/high-time integration of means-end related objects. During a fault detection and diagnosis task, it was found that a low level of integration, high-space/ low-time, provided the fastest fault detection time. However, the most integrated condition, high-space/high-time, resulted in the fastest and most accurate fault diagnosis performance. Actual or potential applications of this research include computer displays for large-scale systems such as network management or process control, for which problem solving is critical and integration must be maintained.

Adult↗
PubMed2000

There is more to monitoring a nuclear power plant than meets the eye.

A fundamental challenge in studying cognitive systems in context is how to move from the specific work setting studied to a more general understanding of distributed cognitive work and how to support it. We present a series of cognitive field studies that illustrate one response to this challenge. Our focus was on how nuclear power plant (NPP) operators monitor plant state during normal operating conditions. We studied operators at two NPPs with different control room interfaces. We identified strong consistencies with respect to factors that made monitoring difficult and the strategies that operators have developed to facilitate monitoring. We found that what makes monitoring difficult is not the need to identify subtle abnormal indications against a quiescent background, but rather the need to identify and pursue relevant findings against a noisy background. Operators devised proactive strategies to make important information more salient or reduce meaningless change, create new information, and off-load some cognitive processing onto the interface. These findings emphasize the active problem-solving nature of monitoring, and highlight the use of strategies for knowledge-driven monitoring and the proactive adaptation of the interface to support monitoring. Potential applications of this research include control room design for process control and alarm systems and user interfaces for complex systems.

Cognitive Science↗
PubMed1999

Activation of Rho-dependent transcription termination by NusG. Dependence on terminator location and acceleration of RNA release.

There is a kinetic limitation to Rho function at the first intragenic terminator in the lacZ gene (tiZ1) which can be overcome by NusG: Rho can terminate transcription with slowly moving, but not rapidly moving, RNA polymerase unless NusG is also present. Here we report further studies with two other Rho-dependent terminators that are not kinetically limited (tiZ2 and lambda tR1) which show that the requirement for NusG depends on the properties of the terminator and its location in the transcription unit. NusG is also shown to increase the rate of Rho-mediated dissociation of transcription complexes arrested at a specific termination stop point in the tiZ1 region and the rates of dissociation with three different Rho factors and two different terminators correlated with their sensitivity to RNA polymerase elongation kinetics. These results suggest a model of NusG function which involves an alteration in the susceptibility of the transcription complex to Rho action which allows termination to occur within the short kinetic window when RNA polymerase is traversing the termination region.

Bacterial Proteins↗
PubMed1999

Perception of weight status and dieting behaviour in Dutch men and women.

OBJECTIVE: To study the perception of weight status, the accuracy of self-assessment of weight status and weight control practices relative to the degree of adiposity in Dutch men and women. DESIGN: A cross-sectional study. SUBJECTS: 2155 men and 2446 women, aged 20-65y, of mostly caucasian origin, non-diabetic, not pregnant or with cancer. MEASUREMENTS: Body weight, height, waist and hip, total cholesterol, high density lipoprotein (HDL) cholesterol, blood pressure, self-administered questionnaire (including questions concerning demographic variables), weight loss practices, dietary intake, participation in sport as part of Dutch Monitoring Project on Risk Factors for Chronic Diseases (MORGEN). RESULTS: In the study population, 53% of men and 39% of women were overweight or obese. An association was shown between degree of adiposity and participation in sport for both men and women, and dietary fat intake in men. Of the subjects studied 56% of men and 52% of women described their weight as appropriate. A degree of inaccuracy in the estimation of relative body weight was observed. While dieting was prevalent, particularly among women, there was a lack of weight control action on the part of many overweight or obese individuals. This effect was most marked in men. Body Mass Index (BMI) was the strongest determinant of weight perception and dieting behaviours with some effect of educational level in men. Physical activity was not widely used as a method of weight control. CONCLUSION: These results point to a need for regular assessment of an individual's relative weight and health risk, gender specific obesity treatments and prevention strategies, and an emphasis in treatment and prevention of obesity on physical activity.

Adult↗
PubMed1998

Combinatorial effects of NusA and NusG on transcription elongation and Rho-dependent termination in Escherichia coli.

The transcription factors NusA and NusG from Escherichia coli are modulators of the RNA polymerase elongation reaction and Rho-dependent transcription termination. NusA decreases the elongation rate and termination efficiency while NusG increases both activities. Both Nus factors are able to physically interact with Rho and with RNA polymerase. Experiments with purified components designed to determine whether these factors act independently or competitively showed that the change in elongation rate was a composite of their individual effects, that the combined effect on termination was dependent on the reaction conditions and that the two factors do not compete for their sites of action for either effect. The two factors were also found not to enhance significantly the slight (20%) inhibition of elongation caused by 200 microM guanosine 3',5'-bisdiphosphate (ppGpp) during transcription in vitro. The results also show that the effects of NusA and NusG on RNA polymerase elongation and Rho function are contrary to the inverse relationship between elongation and termination that is expected for a kinetic coupling of Rho action to RNA polymerase elongation. This property suggests that in addition to their known actions on RNA polymerase that influence the length of pausing, these factors act on some other rate-limiting step of the Rho-dependent termination process.

Bacterial Proteins↗
PubMed1998

Effects of providing comprehensive ambulatory services to children with chronic conditions.

OBJECTIVE: To document the effects of a comprehensive program of care on the resource utilization and cost of care for children with chronic conditions. DESIGN: Descriptive study of 10715 admissions between 1984 and 1995 with analyses of costs based on charges. Comparisons were made with data from a national consortium of academic medical centers and from a national survey of hospitals. A 2-week survey of staff was conducted to identify their use of time in the care of these patients. PATIENTS: Children aged birth through 18 years meeting International Classification of Diseases, Ninth Revision, Clinical Modification criteria for chronic conditions. Patients with acute conditions were used as controls. INTERVENTION: A program of expanded care funded since 1989 by a regional insurance company. RESULTS: Between 1984 and 1995, mean length of stay for children with chronic conditions decreased from 83.9 to 10.6 days; mean annual admissions decreased from 2796 to 1622. Median hospital inpatient charges, adjusted for cost of living, decreased from $26.1 to $14.6 million. A $77.7 million savings occurred for inpatient care, with total expenditures from the insurance program of $3.6 million (a 21:1 ratio). Almost half the professional activities provided for these children were for services that could not be reimbursed in a fee-for-service model. Median adjusted inpatient charges were lower in Rochester, NY ($8746) than in other academic medical centers ($12773) or in a national survey of hospitals ($12462), and fewer children were readmitted within 30 days in Rochester (12.7%) than in other academic medical centers (15.0%). CONCLUSIONS: An investment of funds by a regional insurance company was associated with reduced costs, admissions, and lengths of stay for children with chronic conditions, and resulted in significant savings for the company. This model may be applicable to other centers.

Adolescent↗
PubMed1998

A retroductive theoretical model of the pathway to chemical dependency in nurses.

Much of the research on chemical dependency in nurses over the past 25 years has been a-theoretical and has tended to focus on descriptive characteristics of nurses. This field of study lacks systematic knowledge building and a useful theoretical base. This article focuses on the development of a middle range theory that begins to explicate the transactions of the chemically dependent nurse with the environment and the process through which nurses become addicted. Steiner's theory models approach using retroductive inference was the method selected to develop the theory. Theoretical work from Bandura, Jessor, and Pender were used as source theories to develop the middle range theory presented.

Female↗
PubMed1997

Modulation of AUUUA response element binding by heterogeneous nuclear ribonucleoprotein A1 in human T lymphocytes. The roles of cytoplasmic location, transcription, and phosphorylation.

The heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) shuttles between the cytoplasm and nucleus and plays important roles in RNA metabolism. Whereas nuclear hnRNP A1 has been shown to bind intronic sequences and modulate splicing, cytoplasmic hnRNP A1 is associated with poly(A)+ RNA, indicating different RNA ligand specificity. Previous studies indicated that cytoplasmic hnRNP A1 is capable of high-affinity binding of reiterated AUUUA sequences (ARE) that have been shown to modulate mRNA turnover and translation. Through a combination of two-dimensional gel and proteolysis studies, we establish hnRNP A1 (or structurally related proteins that are post-translationally regulated in an identical manner) as the dominant cytoplasmic protein in human T lymphocytes capable of interacting with the ARE contained within the context of full-length granulocyte-macrophage colony-stimulating factor mRNA. We additionally demonstrate that cytoplasmic hnRNP A1 preferentially binds ARE relative to pre-mRNAs in both cross-linking and mobility shift experiments. RNA polymerase II inhibition increased the binding of ARE (AUBP activity) and poly(U)-Sepharose by cytoplasmic hnRNP A1, while nuclear hnRNP A1 binding was unaffected. Nuclear and cytoplasmic hnRNP A1 could be distinguished by the differential sensitivity of their RNA binding to diamide and N-ethylmaleimide. The increase in AUBP activity of cytoplasmic hnRNP A1 following RNA polymerase II inhibition correlated with serine-threonine dephosphorylation, as determined by inhibitor and metabolic labeling studies. Thus, cytoplasmic and nuclear hnRNP A1 exhibit different RNA binding profiles, perhaps transduced through serine-threonine phosphorylation. These findings are relevant to the specific ability of hnRNP A1 to serve distinct roles in post-transcriptional regulation of gene expression in both the nucleus and cytoplasm.

Adenosine↗