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Biomedical subjects

C D Williams

Publications and source records attributed to C D Williams.

At least 109 records · Page 6Linked to original sources

Information technology and computer-based decision support in diabetic management.

This paper describes the application of computer-based techniques within an intelligent, knowledge-based framework to the management of diabetes. The objectives are to structure data collection and storage so that the relevant patient-specific data are collected and made accessible as needed, and to provide clinical decision support on either a day-by-day or longer timescale as appropriate; these objectives relating to both hospital clinic and general practice. For longer-term management, a prototype rule set (greater than 500 rules) has been developed (coded in Sigma PROLOG), validated and tested on patient data. The data collection programs (written in SCULPTOR) to feed the ruleset have been tested in the hospital clinic and compared with the resident data collection system for usability, and impact on the running of the clinic. Links between the data collection programs and the ruleset program have been written and tested. The computer system will also incorporate a module, combining knowledge-based advisory system and glucose/insulin model as patient simulator, that can be tested as a potential decision aid for adjusting insulin dosage on a daily basis.

Data Collection↗

Computer-assisted diabetic management: a complex approach.

This paper describes the architecture of, and the main reasoning methods involved in, a computer system developed to assist in diabetic management. The system integrates (i) a database module used for blood glucose monitoring, (ii) an interpreter module used to analyse the adequacy of diet and insulin treatment for diabetics, and (iii) an advisory module suggesting alterations in diet and/or insulin regimen in order to improve glycaemic control. The analysis of blood glucose profiles and hypoglycaemic episodes, as well as the suggestions for altered diet and insulin therapy, are based on qualitative and quantitative models of insulin effect and carbohydrate absorption using meal-time related glucose balance and distance from the preselected target (DFT) glucose values as focal concepts in the reasoning process. During the sequence of consultations with the system, a dynamic model of carbohydrate metabolism is gradually adjusted in order to constitute an appropriate simulation for the specific patient. This model is used to confirm the suggestions made by the ADVISOR program and to assist the health care professional in selecting the best control action by predicting the blood glucose profiles resulting from alternative control policies.

Algorithms↗

A consultation system for insulin therapy.

This paper describes a computer system to advice on insulin therapy for diabetic in-patients. A mathematical model was developed to describe the effect of insulin on blood glucose (BG) level. The system uses an adaptive approach to analyse the response to an applied insulin dosage. It learns the patient's individual parameters. All conventional injection and insulin pump regimens are supported. The individualised model is used to predict BG level of the proposed insulin dosage. The system uses a generate-reject strategy to output optimum insulin therapy in terms of optimum BG. The predictive capability of the system was tested and it is able to predict BG with a precision of 2.5 mmol/l after 3 days and 6 days of insulin pump treatment and conventional injection therapy, respectively.

Blood Glucose Self-Monitoring↗

Environmental influences, employment status, and religious activity predict current cigarette smoking in the elderly.

The objective of this study was to describe the smoking histories, patterns of cigarette use, and quitting behaviors in a predominantly African American sample of older adults. Study participants were a convenience sample of senior center attendees in the Washington, DC metropolitan area. Self-report questionnaires were used to measure depression, nicotine dependence, smoking motives, and readiness to quit. Results showed that living with another smoker increased the likelihood of current smoking (odds ratio = 2.07, 95% CI = 1.72-36.73). Being employed or seeking work was also associated with a higher likelihood of current smoking (odds ratio = 2.73, 95% CI = 2.00-118.76). Subjects who reported less frequent participation in organized religious activities were also more likely to smoke (odds ratio = 2.04, 95% CI = 1.17-50.38). Both former and current smokers identified personal will power and physician advice as the two most influential factors in successful smoking cessation. However, current smokers believed that nicotine replacement would aid in a successful cessation attempt, while former smokers did not endorse the efficacy of these products. The findings are discussed in terms of implications for intervention.

Aged↗

Addictive behaviors and depression among African Americans residing in a public housing community.

Numerous studies have indicated that there is an association between cigarette smoking, alcohol use, and depression. However, little attention has been devoted to understanding how demographic factors, such as socioeconomic status and ethnicity, influence these relationships. To address this gap in the literature, cigarette and alcohol use were examined in a sample of African Americans from an urban area. A single public-housing community in Washington, DC was selected for complete ascertainment of the adult population. A total of 126 African American subjects were recruited. Semi-structured interviews were conducted to assess depressive symptoms and to characterize cigarette and alcohol use patterns. Cigarette smoking was not related to the severity of depressive symptoms. By contrast, increased symptoms of depression were related to alcohol use patterns. Light drinkers had a mean score of 5.77 on the Centers for Epidemiologic Studies Depression Scale, compared to a mean of 8.30 for abstainers and 10.07 for heavy drinkers (F = 4.968, p < .003). An analysis of patterns of substance use revealed that subjects were more likely to either abstain from both substances (30.2%) or to use both substances (32.5%) (chi2 = 8.516, df = 1. p < .004). It is unclear which specific processes work to link alcohol use and depressive symptoms in this group of urban African Americans from a low-income community. What is clear is that alcohol use is clearly related to depressive symptoms in the sample. It is hypothesized that both self-medicating processes and substance-induced depressive symptoms may be responsible for these findings. Important factors to consider in developing effective intervention programs that target this specific population are discussed.

Adult↗

Regulation of arrestin mRNA levels in Limulus lateral eye: separate and combined influences of circadian efferent input and light.

Most animals experience daily changes in light and darkness. The retinas of many of these animals show concomitant rhythmic changes in the levels of mRNAs that encode proteins involved in the photoresponse. These changes may be circadian and independent of light, independent of circadian clocks and regulated by light, or regulated by a circadian clock and light. We have taken advantage of the organization of the Limulus visual system to examine the separate and combined effects of signals from a circadian clock and light on arrestin mRNA levels in photoreceptors. The clock that regulates photoreceptors in the lateral eye of Limulus is in the brain, and signals from the clock reach the lateral eye via activation of a well-characterized efferent projection in the lateral optic nerve. In the experiments described, clock-driven efferent input to the lateral eye was eliminated by cutting the lateral optic nerve, and light input to the lateral eye was eliminated by placing an opaque patch over the eye. Arrestin mRNA levels were quantified relative to 18s rRNA with a ribonuclease protection assay. We observed the following. In lateral eyes exposed to natural diurnal light and endogenous efferent nerve activity, the level of arrestin mRNA was higher during the day in the light than during the night in the dark. Circadian efferent nerve activity was necessary and sufficient to produce normal daily fluctuations in the level of arrestin mRNA. Light influenced arrestin mRNA levels only in eyes with intact and active efferent projections. We conclude that arrestin mRNA levels in lateral eye photoreceptors are controlled entirely by efferent nerve activity, and that light exerts its effects by modulating this output from the circadian clock. Light-stimulated changes in arrestin mRNA in the vertebrate retina may likewise require interactions between light-driven biochemical cascades and clock output.

Animals↗

Lymphoma in a pelvic spleen: CT features.

A case of recurrent lymphoma presenting as a pelvic mass on CT is described. At surgery this proved to represent an ectopic spleen with lymphomatous infiltration.

Female↗

Use of memory meters to measure reliability of self blood glucose monitoring.

Glucose reflectance meters equipped with memories were used in 21 insulin-dependent diabetic patients to assess reliability of self blood glucose monitoring records. Results reported in logbooks showed widespread discrepancies when compared with corresponding meter-held records. Discrepancy rates of at least one in five were observed in 11 patients. Unreliable reporting was usually recognized by clinical staff, and associated with high glycosylated haemoglobin levels and poor technique in measuring blood glucose at home.

Adult↗

Psychosocial and demographic correlates of television viewing.

PURPOSE: The present study was grounded in the notion that previously identified physical activity determinants were associated in reverse with television viewing. Identifying demographic and psychosocial correlates and other potential determinants of television viewing may allow for the development and conceptualization of models and interventions to reduce sedentary behavior. DESIGN: Cross-sectional data from self-report measures were analyzed using multiple hierarchical regression. SETTING: Data were collected from 1995 to 1996 on seniors attending a large public university in southern California. SAMPLE: Subjects were 321 female and 255 male university seniors attending a public university in southern California. The sample's ethnic distribution was 53.8% European-American, 16.3% Latino, 16.6% Asian/Pacific Islander, 16.1% African-American, and 4.3% other. MEASURES: Typical television viewing practices on weekdays and weekends were assessed using self-report items. Physical activity determinants were assessed using self-report measures derived from social cognitive theory and the transtheoretical model of behavior change. RESULTS: The variables explaining a significant amount of variance after controlling for ethnicity and employment status in females were barriers to physical activity (p < .05), body image dissatisfaction (p < .01), and processes of change (p < .02). The entire model for females captured 16% of the variance, with the psychosocial variables accounting for 8% of the variance. The significant variables in the male model were quality of life (p < .01) and grade point average (p < .03). The full model accounted for 15% of the variance, with nondemographic variables accounting for 5% of the variance in television viewing. CONCLUSIONS: Relationships between television viewing and potential determinants were found. However, additional variables that may influence the amount of television viewing need to be conceptualized and investigated.

Adult↗

Therapeutic electromagnetic field effects on angiogenesis and tumor growth.

BACKGROUND: A new approach to cancer therapy based on the application of therapeutic electromagnetic fields (TEMF) has been developed by EMF Therapeutics, Inc., Chattanooga, TN, USA. This study was designed to assess the effect of TEMF on tumor vascularization and growth of murine 16/C mammary adenocarcinoma cells in C3H/HeJ mice. MATERIALS AND METHODS: Implanted tumors were allowed to grow for seven days until the tumor volume reached 100 mm3 before treatment was started. Mice (20 per control, 10 per EMF exposed group) received treatment (10 minutes per day with 0, 10 mT, 15 mT or 20 mT) with a 120 pulses per second pulsating magnetic field. Tumor growth was assessed throughout the treatment period. The extent of tumor vascularization was evaluated by immunohistochemical staining for CD31. RESULTS: Exposure to TEMF significantly reduced tumor growth, significantly reduced the percentage of area stained for CD31 indicating a reduction in the extent of vascularization and there was a concomitant increase in the extent of tumor necrosis. CONCLUSION: A novel TEMF treatment safely reduced growth and vascularization of implanted breast cancers in mice. IMPLICATION: TEMF may prove a useful adjuvant to increase the therapeutic index of conventional cancer therapy.

Adenocarcinoma↗