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R D Stevens

Publications and source records attributed to R D Stevens.

49 records · Page 3Linked to original sources
PubMed1984

Variability in the management of hypertension and cost-effectiveness: methodology, community care results and potential cost reductions.

This study examined factors contributing to variability in the cost-effectiveness of managing hypertension using the Weinstein and Stason methodology. Empirical analysis was based on resource use and blood pressure data from 160 persons ages 25-64 in an urban community family practice center in 1976. The exploratory study presented results on blood pressure reduction, annual treatment costs, the importance of different cost factors, variability in management costs and potentials for increasing cost-effectiveness. For males cost-effectiveness estimates were similar to those of Weinstein and Stason , while the results for women were somewhat different due to less cost-effectiveness in hypertension management for older women. With small modifications in current Family Practice procedures the cost-effectiveness of managing hypertension appears to be able to be increased in many cases by as much as one-third.

Adult↗
PubMed1980

Fat digestion in patients with bile acid malabsorption but minimal steatorrhea.

Patients with an interrupted enterohepatic circulation of bile acids and minimal or no steatorrhea were studied to determine if their fat absorption was aided by compensatory mechanisms which delivered increased amounts of lipid to the aqueous phase of post-prandial duodenal fluid. The data suggested that the molar stoichiometry of association of fatty acid and bile acid in an aggregated (micelle) form was reduced in the patients (0.8) as compared to normals (1.4). Each patient had either normal sized or undetectable micelles; one patient had a large fatty acid-rich aggregated species. The bile acid composition of the whole duodenal fluid was found to have an increased proportion of dihydroxy bile acids which were conjugated with glycine. There was a selective precipitation of dihydroxybile acids from the aqueous phase, such that the patients had a normal proportion of these bile acids in the aqueous phase. We were unable to identify a consistent compensatory mechanism whereby these patients could increase the concentration of lipid in the aqueous phase which would have led to a better understanding of their minimal steatorrhea. We believe that the reduced stoichiometry of aggregated fatty acid to aggregated bile acid is in part due to the altered bile acid pool composition of these patients.

Bile Acids and Salts↗
PubMed1980

The laboratory method as a variable in the interpretation of serum bilirubin fractionation.

Fractionation of the serum bilirubin into direct and indirect-reacting components has been used in the differentiation of patients with hepatobiliary disease from those with unconjugated hyperbilirubinemia. Previous studies have shown that patients with indirect hyperbilirubinemia usually have total serum bilirubin concentrations less than 5 mg/dl. Therefore, clinically useful methods of fractionating bilirubin must yield reliable results in patients with mild hyperbilirubinemia. Experience with 4 patients with mild hyperbilirubinemia indicated that conflicting results could be obtained from two different laboratories. Therefore, a panel of hyperbilirubinemic sera were submitted to four different laboratories. While there was general agreement in sera containing high concentrations of bilirubin, marked variations were observed in the results reported on sera with less than 5 mg/dl total bilirubin. Finally, clinical and other laboratory parameters were reviewed in patients who had had bilirubin fractionation performed by one or the other of two routine laboratories. In one laboratory, bilirubin fractionation correctly distinguished patients with hepatobiliary disease, while the other laboratory was not able to differentiate patients on the basis of this test. These data suggest that despite the general reported agreement in standard methods for bilirubin fractionation there may be marked differences among methods in ability to reliably fractionate sera with total bilirubin concentrations less than 5 mg/dl.

Adult↗
PubMed1978

Lymph-node bacilliform bodies resembling those of Whipple's disease in a patient without intestinal involvement.

A 38-year-old man developed symptoms of arthalgias and arthritis, lymphadenopathy, and weight loss. An axillary lymph-node biopsy was done in the diagnostic study; a periodic acid Schiff stain, done for evidence of fungal infection, showed periodic acid Schiff reagent-positive macrophages. Electron microscopy showed the typical morphologic features of the bacilliform bodies associated with Whipple's disease to be present in the macrophages of the lymph node. The patient had no intestinal symptoms. The absorption of a variety of substrates was found to be normal. Nine intestinal biopsies showed no organisms similar to those found in his lymph node. On tetracycline therapy, he symptomatically improved. The findings raise the question of the route of infection in Whipple's disease and point up the usefulness of periodic acid Schiff staining of lymph-node biopsies.

Adult↗
PubMed1977

An electron spin resonance study of cholestane spin label in aqueous mixtures of biliary lipids.

The effect of cholesterol on the fluidity of the phospholipid matrix in mixed micelles derived from bile salts and lecithin has been determined by the paramagnetic probe technique. It was found that correlation times for the cholestane spin label were discontinuous functions of cholesterol content and that these discontinuities correlate with the equilibrium solubility limit for cholesterol in this quaternary system. The origin of these discontinuities is attributed to the existence of another aggregate in addition to the discshaped mixed micelle in lipid solutions supersaturated with cholesterol.

Bile↗