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Biomedical subjects

D S Bell

Publications and source records attributed to D S Bell.

At least 37 records · Page 2Linked to original sources
PubMed1999

Dealing with diabetic nephropathy.

Nephropathy may develop in patients with type 1 diabetes because poor glycemic control produces effects that eventually lead to glomerular scarring and renal failure. The worse and more prolonged the hyperglycemia, the greater the risk of diabetic nephropathy. In patients with type 2 diabetes, hyperglycemia, as well as insulin resistance and generalized vascular disease, is involved in the pathogenesis of nephropathy. The glomerular changes of early diabetic nephropathy can be identified only by renal biopsy or by testing for microalbuminuria. Once macroalbuminuria occurs (albumin excretion rate, > 300 mg/day), usually after type 1 diabetes has been present for 10 to 15 postpubertal years, end-stage renal disease is almost inevitable. However, aggressive control of hypertension in diabetic patients without microalbuminuria helps avoid nephropathy, and tight glycemic control in those with microalbuminuria can avoid or delay its onset. Even when macroalbuminuria is present, treatment can prolong renal function. Aggressive antihypertensive therapy, especially with ACE inhibitors, can reduce renal decline by half. Avoiding circumstances that may damage the kidneys (e.g., use of radiocontrast materials or nephrotoxic drugs, dehydration, hyperlipidemia, urinary tract infection, buildup of AGEs) is critical. Some treatment methods are controversial (dietary protein restriction) or still under investigation (use of injected or oral heparin) but may help delay renal transplantation or dialysis.

Diabetic Nephropathies↗
PubMed1997

Diabetic ketoacidosis. Why early detection and aggressive treatment are crucial.

Diabetic ketoacidosis is a preventable condition that usually has a satisfactory outcome. However, the potential for a poor outcome and even death demands early and aggressive treatment. Insulin administration, rehydration, and electrolyte replacement are the mainstays of treatment. A search for the underlying cause is also a priority if recurrences are to be avoided.

Diabetic Ketoacidosis↗
PubMed1997

Decision-analytic valuation of clinical information systems: application to an alerting system for coronary angiography.

BACKGROUND: Many patients who need coronary angiography fail to get it and they have decreased survival as a result. This study demonstrates the use of decision analysis to predict the survival value of an alerting system for necessary angiography. METHODS: Data on the use of angiography and survival after myocardial infarction (MI) were taken from a published cohort study. The expected value of information (EVI) was calculated for alerts that angiography is necessary. Maximal EVI was estimated by assuming that alert advice is always followed. Sensitivity analysis relaxed that assumption. Hypothetical data were generated to demonstrate EVI analysis for narrower subcohorts. RESULTS: A maximally effective alerting system would increase survival in this cohort by 2.2% over 1-4 years after MI. The system would therefore need to be applied to 46 people to prevent one death. Its effectiveness would decrease linearly with decreasing adherence to its advice. Given sufficiently detailed outcome and prevalence data, EVI analysis could also predict the survival value of the system's individual data elements. CONCLUSIONS: An alerting system that ensures necessary angiography post-MI should have a survival value comparable to the value of t-PA over streptokinase. EVI analysis provides a framework for predicting the overall effectiveness of information systems and for understanding the contribution of individual features to a system's effectiveness.

Cohort Studies↗
PubMed1996

Structured entry of radiology reports using World Wide Web technology.

Structured data entry--in which information is entered by using predetermined data elements and formats--has the potential to improve the radiology reporting process. The dependence on particular computer hardware and software platforms has posed a barrier to wider use of this approach. The World Wide Web (WWW), a client-server protocol for delivery of multimedia data via the Internet, was used to achieve platform-independent structured entry of radiology reports. A developmental system for structured entry of radiology reports, called SPIDER, incorporates a knowledge base of hierarchically organized concepts, a WWW server, and two specialized programs. The WebForm program transforms the system's knowledge into graphical WWW data-entry forms; the WebReport program converts data entered on these forms into outline-format reports. SPIDER received favorable evaluations from sonographers and physicians who used the system to record the results of several test cases. WWW technology can be used to achieve platform-independent entry of the results of radiologic procedures.

Artificial Intelligence↗
PubMed1996

Alcohol and the NIDDM patient.

Historically, alcohol use by the diabetic patient has been controversial. Recent studies in the general population have shown an improvement in mortality with moderate alcohol intake (one to three drinks per day). This improved mortality is greatest in those individuals who have a higher risk of ischemic heart disease. The mechanisms of the beneficial effects of alcohol include positive effects on insulin resistance, HDL cholesterol, platelet aggregation, and fibrinolysis. Since the diabetic patient has an especially high risk of ischemic heart disease because of these factors, the use of a moderate amount of alcohol should not be discouraged. The short-term risks of heavy or continuous alcohol intake include hypoglycemia, glucose intolerance, and ketone and lactate accumulation. In the long term, heavy alcohol intake is associated with an increased prevalence of cancer, hypertension, cirrhosis of the liver, and symptomatic neuropathy. Moderate alcohol intake taken with a meal has been shown to have little or no effect on postprandial glycemic excursions.

Alcohol Drinking↗
PubMed1996

Health status assessment via the World Wide Web.

We explored the use of the World Wide Web to collect health status information for medical outcomes research. The RAND 36-Item Health Survey 1.0 (RAND-36), which contains the 36 multiple-choice questions of the Medical Outcomes Study SF-36 "Short Form" and differs only in its simplified scoring scheme, was made available for anonymous use on the Internet. Participation in the survey was invited through health-related Internet news groups and mailing lists. Participants entered data and received, their scores using the World Wide Web protocol. Entries were recorded from 15 June 1995 to 14 June 1996 (1 year). The survey was completed anonymously by 4876 individuals with access to the World Wide Web. Two-thirds completed the survey within 5 minutes, and 97% did so within 10 minutes. The item-completion rate was 99.28%. Values of Cronbach's alpha of 0.76 to 0.90 for the scoring scales matched the high reliability found in the Medical Outcomes Study. The World Wide Web provides a method of rapidly measuring individual health status and may play an important role in advancing health services research and outcomes-based patient care.

Computer Communication Networks↗
PubMed1995

The motivation of addiction.

The addict pursues the drug effect despite its damaging impact. The aberration results from the side-tracking of a mood-dominated activity, which utilises automatic mechanisms beyond conscious introspection to regulate the pursuit of pleasure. The indirect nature of the mechanism creates the potential for its subversion. Drug use, for the non-addicted as well as the addict, bypasses the primary purpose of the pleasure principle, the motivation to achieve success. Instead, drug use produces pleasure on demand. The addict abandons the effort of striving for a goal, which has an uncertain chance of success, in preference for the certainty of the drug-induced pleasure. The sequence of unpleasure following pleasure, each proportional to the other, brings each response to a timely end and so sets in train renewed effort to achieve success and the chance of yet another bout of pleasure. The sequence delivers pleasure only on condition of prior payment or, in the case of drug use, "trip now and pay later". The bipolar nature of the pleasure principle draws comparison to a similar bipolarity extending throughout the structure and function of existence.

Affect↗
PubMed1995

Segmentation and analysis of colour Doppler images of tumour vasculature.

A technique has been developed to segment (separate), from a digitized colour Doppler video image, the colour and greyscale information and then to estimate from the colour information the original mean Doppler frequency shift data from which the image was created. The remapped velocity image is then analysed to extract numerical features of the tumour vasculature. The present version of the software is set-up to work for an Acuson 128 colour Doppler system using the V4 colour scale, although it should work well with any system which modulates only two colours for each flow direction and displays a colour calibration scale at the side of the image. Accuracy of classification of greyscale, colour and flow direction was estimated as being in the region of 95% for typical breast tumour images. The degree of agreement between the remapped colour velocity values and those stated by the scanner at the same image locations was evaluated in terms of the linearity of the relationship (> 99%), precision (better than +/- 5%) and accuracy (better than 7.6%). We investigated the value, for diagnosis and assessment of response of, a variety of characteristics of the displayed vascularity. At present, the software calculates the following vascular image features within any region of interest defined by the operator: mean displayed velocity, maximum displayed velocity, standard deviation of displayed velocity, total area occupied by colour signal, percentage area occupied by colour signal, area integral of displayed velocity and the total displayed velocity per unit area.

Algorithms↗
PubMed1995

Colour DOPPLER image analysis for tissue vascularity and perfusion: a preliminary clinical evaluation.

An automated system for measuring features of colour Doppler (CD) images has been examined for its ability to measure tissue perfusion in vivo under conditions of diffuse vascularity. Seven statistical features were extracted from CD images of human calf muscle and compared with the arterial input measured by plethysmography. It was found that, when appropriate scanning procedures are employed, good correlation is achieved with arterial input (r = 0.96 to 0.99). Ultrasound beam angle was important, even for the assessment of "colour area." A sensitive velocity scale was ideal for "percentage colour" (r = 0.979). "Mean colour velocity" correlates well with arterial input (r = 0.979) when the volocity scale was optimised for each CD scan. "Integrated colour velocity per unit area" was more responsive when using a variable velocity scale (r = 0.99) than a fixed velocity scale (r = 0.98), but was less responsive to low flow. Automated CD analysis speeds up the process of quantitative assessment of tissue vasculature and perfusion. It is therefore essential for the analysis of dynamic studies of ultrasound contrast agents and serial examinations when monitoring response to therapy.

Arteries↗