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Biomedical subjects

D S Bell

Publications and source records attributed to D S Bell.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

A comparison of lovastatin, an HMG-CoA reductase inhibitor, with gemfibrozil, a fibrinic acid derivative, in the treatment of patients with diabetic dyslipidemia.

Hyperlipidemia associated with non-insulin-dependent diabetes mellitus (NIDDM) and insulin resistance is characterized by high triglyceride levels; raised levels of total low-density lipoprotein (LDL), which is made up of small, dense, cholesterol-rich particles; low levels of high-density lipoprotein (HDL); and glycosylation of apolipoproteins. Optimal drug therapy for this lipid profile is controversial. To test whether a fibrinic acid derivative (gemfibrozil) or a 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor (lovastatin) would produce better results in these patients, a crossover study was performed. Gemfibrozil 600 mg twice daily and, after a washout period, lovastatin 20 to 40 mg twice daily were administered to nine patients with NIDDM. Gemfibrozil significantly decreased triglyceride, very-low-density lipoprotein (VLDL), and intermediate-density lipoprotein (IDL) levels, the total cholesterol:HDL ratio, and the IDL plus VLDL;HDL ratio, and significantly increased levels of HDL, HDL2, and HDL3. Lovastatin significantly decreased levels of total cholesterol, calculated LDL, directly measured LDL, IDL, total triglycerides, VLDL, and the ratios of LDL:HDL, total cholesterol:HDL, and directly measured LDL:HDL and significantly increased total HDL and HDL3 levels. Gemfibrozil was significantly more effective than lovastatin in raising total HDL and HDL3 levels and in lowering the IDL plus VLDL:HDL ratio. Lovastatin was significantly more effective than gemfibrozil in lowering total cholesterol, LDL, directly measured LDL, and the LDL:HDL and directly measured LDL:HDL ratios. In the absence of malignant hypertriglyceridemia, an HMG-CoA reductase inhibitor, rather than a fibrinic acid derivative, is indicated for the treatment of patients with dyslipidemia associated with NIDDM and insulin resistance.

Adult↗
PubMedDate not supplied

Risk factors associated with chronic fatigue syndrome in a cluster of pediatric cases.

After seven pediatric cases of chronic fatigue syndrome (CFS) were diagnosed in a farming community in upstate New York, a questionnaire regarding symptoms and potential risk factors of CFS was distributed to all students enrolled in the same school district. Twenty-one students with symptoms of CFS were identified. Two controls per case matched for age and sex were randomly selected from questionnaire respondents. Health status was verified for all subjects by telephone, and diagnosis of CFS was confirmed by a physician. Information was collected on the following factors: symptoms of CFS among other family members; history of allergy/asthma; consumption of raw milk, raw eggs, raw cheese, or raw meat; water supply; exposure to animals; home heating source; proximity to farmland/orchards; tick bite; blood transfusion; camping; and appendicitis. Logistic-regression analyses indicated that the best model (characterized by symptoms among other family members, recent ingestion of raw milk, and history of allergy/asthma) produced significant estimates of relative risk (P less than .05) of 35.9, 44.3, and 23.3, respectively, for the three factors (corrections were made for the effect of the other covariates). These data suggest that a combination of host and environmental factors, including an infectious agent or agents, are involved in the etiology of CFS.

Adolescent↗
PubMedDate not supplied

The future of clinical engineering in the 1990's.

The problems in hospitals which led to the development of the clinical engineering profession are described along with recent changes in the hospital environment. The authors discuss how the profession is adapting to these changes. Also discussed is the tendency for BMETs to move into clinical engineering roles.

Biomedical Engineering↗
PubMedDate not supplied

Toward a medical-concept representation language. The Canon Group.

The Canon Group is an informal organization of medical informatics researchers who are working on the problem of developing a "deeper" representation formalism for use in exchanging data and developing applications. Individuals in the group represent experts in such areas as knowledge representation and computational linguistics, as well as in a variety of medical subdisciplines. All share the view that current mechanisms for the characterization of medical phenomena are either inadequate (limited or rigid) or idiosyncratic (useful for a specific application but incapable of being generalized or extended). The Group proposes to focus on the design of a general schema for medical-language representation including the specification of the resources and associated procedures required to map language (including standard terminologies) into representations that make all implicit relations "visible," reveal "hidden attributes," and generally resolve ambiguous or vague references. The Group is proceeding by examining large numbers of texts (records) in medical sub-domains to identify candidate "concepts" and by attempting to develop general rules and representations for elements such as attributes and values so that all concepts may be expressed uniformly.

Computer Simulation↗
PubMedDate not supplied

Experiments in concept modeling for radiographic image reports.

OBJECTIVE: Development of methods for building concept models to support structured data entry and image retrieval in chest radiography. DESIGN: An organizing model for chest-radiographic reporting was built by analyzing manually a set of natural-language chest-radiograph reports. During model building, clinician-informaticians judged alternative conceptual structures according to four criteria: content of clinically relevant detail, provision for semantic constraints, provision for canonical forms, and simplicity. The organizing model was applied in representing three sample reports in their entirety. To explore the potential for automatic model discovery, the representation of one sample report was compared with the noun phrases derived from the same report by the CLARIT natural-language processing system. RESULTS: The organizing model for chest-radiographic reporting consists of 62 concept types and 17 relations, arranged in an inheritance network. The broadest types in the model include finding, anatomic locus, procedure, attribute, and status. Diagnoses are modeled as a subtype of finding. Representing three sample reports in their entirety added 79 narrower concept types. Some CLARIT noun phrases suggested valid associations among subtypes of finding, status, and anatomic locus. CONCLUSIONS: A manual modeling process utilizing explicitly stated criteria for making modeling decisions produced an organizing model that showed consistency in early testing. A combination of top-down and bottom-up modeling was required. Natural-language processing may inform model building, but algorithms that would replace manual modeling were not discovered. Further progress in modeling will require methods for objective model evaluation and tools for formalizing the model-building process.

Computer Simulation↗
PubMedDate not supplied

Randomized testing of alternative survey formats using anonymous volunteers on the World Wide Web.

Consenting visitors to a health survey Web site were randomly assigned to a "matrix" presentation or an "expanded" presentation of survey response options. Among 4,208 visitors to the site over 3 months, 1,615 (38 percent) participated by giving consent and completing the survey. During a pre-trial period, when consent was not required, 914 of 1,667 visitors (55 percent) participated (odds ratio 1.9, P<0.0001). Mean response times were 5.07 minutes for the matrix format and 5.22 minutes for the expanded format (P=0.16). Neither health status scores nor alpha reliability coefficients were substantially influenced by the survey format, but health status scores varied with age and gender as expected from U.S. population norms. In conclusion, presenting response options in a matrix format may not substantially speed survey completion. This study demonstrates a method for rapidly evaluating interface design alternatives using anonymous Web volunteers who have provided informed consent.

Health Status↗
PubMedDate not supplied

Oral candidiasis in patients with diabetes mellitus: a thorough analysis.

It has generally been assumed that oral candidiasis occurs with increased frequency in patients with diabetes mellitus. To evaluate this, we compared the frequency and severity of oral Candida colonization in 60 patients with insulin-dependent diabetes mellitus (IDDM) admitted to a low-intensity-care diabetes unit with those in 57 age- and sex-matched controls. Swabs taken from the tongue and buccal mucosa were examined by cytology rather than culture because of the discrimination provided by the former. Cytological smears were classified according to the presence and morphology of the Candida organisms. Overall, a significant difference in Candida species colonization was found between patients with diabetes (75.0%) and controls (35.1%) (P less than .005). In the diabetic group, no relationship was found to recent use of antibiotics, total or differential white blood cell count, serum glucose, presence of diabetic retinopathy, or glycosylated hemoglobin values. We conclude that in IDDM there is a predisposition to oral candidiasis and that this predisposition is independent of glucose control.

Adolescent↗
PubMedDate not supplied

An evaluation of patient performance of and their satisfaction with various rapid blood glucose measurement systems.

We evaluated the performance of 50 insulin-dependent diabetic patients in the measurement of their own capillary blood glucose concentrations using Chemstrip bG, Dextrostix-Dextrometer, and Stat Tek systems. With all systems, patient performance was suboptimal when compared with the accuracy of paramedical personnel. The percentage of patient determinations that differed from the laboratory value by more than 20% was 37%, 30%, and 14% for the Chemstrip bG, Dextrostix-Dextrometer, and Stat Tek systems, respectively. Only 39 of the patients (78%) could perform accurately with any system. Youth, lack of a higher education, and lower income status contributed significantly to the patients' inaccuracy with the Chemstrip bG technique, whereas these factors had no effect on patient performance with the reflectance meter techniques. Nearly all of the patients were enthusiastic about the value of home glucose monitoring as a means to assess their glycemic control. However, only 30% of the patients selected for home use a technique at which they were suitably adept. In part, this selection error appeared to be due to the greater cost and inconvenience of the reflectance meter techniques compared with the Chemstrip bG technique. These data indicate that unless proper instruction is provided, home glucose monitoring should only be used by a fraction of insulin-requiring diabetic patients and the choice of a particular system for use by an individual patient should be predicated upon his or her demonstrated proficiency with that system.

Adolescent↗
PubMedDate not supplied

Nondiabetic neuropathy in a patient with diabetes.

A case of peripheral neuropathy in a patient with diabetes who had atypical clinical findings is presented. Because of the atypical initial manifestations and short duration of insulin-dependent diabetes, another cause of the neuropathy was suspected. The presence of vitiligo, hypothyroidism, and diabetes prompted a search for evidence of pernicious anemia. Despite a normal blood cell count, the diagnosis of pernicious anemia was confirmed on the basis of an increased serum gastrin level and antiparietal cell antibody titer. Treatment with vitamin B12 resulted in an arrest, but not a reversal, of the signs of peripheral neuropathy. In patients with diabetes, vitamin B12 deficiency should be suspected; its early diagnosis and treatment are important in minimizing neurologic damage.

Journal Article↗
PubMedDate not supplied

Outcome of metformin-facilitated reinitiation of oral diabetic therapy in insulin-treated patients with non-insulin-dependent diabetes mellitus.

OBJECTIVE: To test the feasibility of reimplementation of oral diabetic therapy in insulin-treated patients with non-insulin-dependent diabetes mellitus (NIDDM) and to determine the characteristics of patients in whom such conversion was successful. METHODS: We attempted reinitiation of combination oral therapy with metformin and a sulfonylurea in 55 consecutive C-peptide-positive patients who had had NIDDM for less than 30 years and had received insulin therapy for less than 10 years. RESULTS: Reinitiation of oral therapy was successful in 42 patients and unsuccessful in 13. Reinitiation of oral therapy was unsuccessful because of lack of diabetic control in nine patients and gastrointestinal side effects in four patients. The successful group had a lower insulin requirement (P = 0.004), a shorter duration of insulin therapy (P = 0.013), and a lower body mass index (P = 0.014). Baseline glycosylated hemoglobin, C-peptide level, age, and duration of diabetes were not significant predictive factors. Glycosylated hemoglobin levels were significantly lower (mean, 1.3%; P = 0.0001) after successful reinitiation of oral therapy in comparison with before. Both groups of patients (those with successful and those with unsuccessful conversion to oral therapy) lost weight. CONCLUSION: The group of patients with NIDDM in whom reinitiation of combination oral therapy is most likely to be successful are those with a shorter duration of insulin therapy, lower insulin requirements, and lower body mass index. Successful conversion to oral diabetic therapy significantly decreases the glycosylated hemoglobin level.

Journal Article↗
PubMedDate not supplied

Frequency of severe hypoglycemia in patients with non-insulin-dependent diabetes mellitus treated with sulfonylureas or insulin.

OBJECTIVE: To assess the frequency of severe hypoglycemia in patients with non-insulin-dependent diabetes mellitus (NIDDM). METHODS: We surveyed a single diabetologist's clinical practice of consecutive patients with NIDDM during a 3-month period. RESULTS: Of the 262 study participants interviewed, 172 insulin-using and 90 sulfonylurea-using patients were asked whether they had ever had hypoglycemia severe enough to require the assistance of another person. Of the 90 sulfonylurea-treated patients with NIDDM, 3 (3.3%) reported experiencing severe hypoglycemia on one occasion only. Of the 172 insulin-utilizing patients, 13 (7.6%) had had severe hypoglycemic episodes--8 on one occasion only (5 of these had been iatrogenic circumstances and 3 had been precipitated by exercise or lack of food). Five insulin-requiring patients reported multiple bouts of severe hypoglycemia. With one exception, all patients were thin, and C peptide levels were low or undetectable. CONCLUSION: On the basis of this study, we conclude that severe hypoglycemia is extremely uncommon in NIDDM. When it occurs, it is usually accidental and seldom recurs. Patients with multiple bouts of severe hypoglycemia have almost complete insulin deficiency. Thus, aggressive treatment of NIDDM to avoid diabetic complications is rarely associated with severe hypoglycemia and is usually well tolerated.

Journal Article↗
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Improved glycemic control with use of oral hypoglycemic therapy with or without insulin.

OBJECTIVE: To determine whether combination oral hypoglycemic therapy in insulin-using patients with non-insulin-dependent diabetes mellitus (NIDDM) can improve glycemic control for a prolonged period. METHODS: We expanded and extended an earlier study to include 130 patients with NIDDM for 10 to 30 years who had been using twice-daily mixed insulin for less than 10 years. Reduction and eventual elimination of the insulin therapy and substitution of metformin and a sulfonylurea were attempted. At follow-up visits, patients were weighed, random plasma glucose levels were determined, and glycosylated hemoglobin values were obtained. RESULTS: Of 130 C-peptide-positive patients with NIDDM receiving twice-daily mixed insulin, 100 were successfully transferred to combination oral hypoglycemic therapy with glyburide originally and later glimepiride and metformin--a primary failure rate of 23.1%. Secondary failure occurred in 20 patients after a mean duration of 6.4 months. Two patients with successful conversion to oral combination therapy resumed insulin treatment because of cost. Of the patients with primary failures, 6 had gastrointestinal side effects, 10 were successfully managed on combination oral therapy plus evening mixed insulin, and 14 ultimately received twice-daily insulin and metformin. Of the secondary failures, 13 were controlled on combination oral therapy plus evening insulin and 7 on twice-daily insulin in conjunction with metformin. No difference was found in the original C-peptide levels among these three groups. Glycosylated hemoglobin levels were significantly less on combined oral hypoglycemic therapy (9.8% versus 8.3%; P = 0.0001), on combination oral therapy plus evening insulin (11.2% versus 9.7%; P = 0.001), and on return to twice-daily mixed insulin with metformin (11.0% versus 9.9%; P = 0.04). Those eight patients who resumed twice-daily insulin therapy alone, however, had a nonsignificant increase in glycosylated hemoglobin (9.3% versus 9.9%). CONCLUSION: Improvement in glycosylated hemoglobin level in insulin-using patients with NIDDM can be obtained with combination oral therapy alone, combination oral therapy with once-daily evening insulin, or twice-daily mixed insulin with metformin in comparison with twice-daily insulin alone.

Journal Article↗
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Triple oral antidiabetic therapy in type 2 diabetes mellitus.

To determine the effectiveness of triple oral antidiabetic therapy with a sulfonylurea, a biguanide, and a thiazolidinedione, we analyzed the results in 35 patients who had previously had inadequate glycemic control with a combination of glimepiride and metformin. The study cohort consisted of 27 men and 8 women (mean age, 55.8 years) who had had type 2 diabetes mellitus for a mean duration of 8.7 years. The addition of troglitazone (600 mg/day administered with the largest meal) to the glimepiride and metformin therapy yielded normal or near-normal glycemia in all 35 patients. Glycemic control was initially associated with mean weight gain; subsequently, however, mean weight was reduced to below the baseline level--perhaps attributable to the anorectic effect of metformin. Thus, for the first time, triple oral antidiabetic therapy with glimepiride, metformin, and troglitazone has been shown to be an efficacious therapeutic option for type 2 diabetes.

Journal Article↗
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Health-care charges generated by patients with diabetes.

For assessment of health-care charges generated by patients with diabetes, 50 patients (25 who were older than 65 years and 25 who were age 65 or younger) whose primary care had been delivered between 1990 and 1995 by a single diabetologist were randomly selected. Institutional health-care bills were accessed from all but three medical center billing offices (dermatology, psychiatry, and radiation oncology areas did not respond). For each dollar billed by endocrinology, the hospital billed 25.90 dollars, other medical specialties 2.70 dollars, surgery 1.10 dollars, radiology 0.70 dollars and pathology 0.60 dollars. The charges generated by the endocrinologist-diabetologist account for approximately 3% of the total charges for the care of the patient with diabetes mellitus in a fee-for-service practice. Although the endocrinologist-diabetologist provides the most cost-effective medical service for patients with diabetes, low reimbursement jeopardizes the practice of this subspecialty.

Journal Article↗
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Weight loss in patients with diabetes treated with a metformin-sulfonylurea combination in comparison with twice-daily mixed insulin.

OBJECTIVE: To investigate whether patients previously treated with insulin or sulfonylureas alone can be transferred to a combination of sulfonylureas and metformin therapy and realize a prolonged weight loss. METHODS: We conducted a retrospective review of medical records to identify three groups of patients with type 2 diabetes: group 1, those requiring insulin who had remained on a daily regimen of two injections of mixed insulin; group 2, patients whose regimen had been changed from sulfonylureas alone to a combination of a sulfonylurea and metformin; and group 3, patients whose regimen had been converted from twice-daily mixed insulin alone to a sulfonylurea-metformin combination. Results relative to loss of weight in these three groups were analyzed. RESULTS: For a 12-month period, no significant weight loss was noted in group 1, and group 2 showed a small nonsignificant weight loss in 6 months. Only group 3 had a significant weight loss at 3, 6, 9, and 12 months, maximizing at a mean weight loss of 22 lb (10 kg) at 12 months. In addition, in those patients in whom data were available, a significant weight loss was found at 18 and 21 months. At 21 months, however, weight began to increase. Percentage weight loss followed a pattern similar to that seen with total weight loss. The proportion of patients losing weight did not differ significantly in groups 1 and 2; however, in group 3, after 3 and 12 months a significant proportion of patients (79% and 86%, respectively) had lost weight. Race, gender, or baseline body weight had no effect on weight loss. CONCLUSION: From this retrospective study of patients with type 2 diabetes, we conclude that conversion from insulin to combination oral therapy with sulfonylureas and metformin results in a significant weight loss for up to 21 months.

Journal Article↗