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R F Dons

Publications and source records attributed to R F Dons.

25 records · Page 2Linked to original sources
PubMed1981

The insulin receptor is an age-dependent integral component of the human erythrocyte membrane.

Human erythrocytes were separated according to age to determine whether there is heterogeneity in the specific binding of 125I-insulin to red cells. The mean cell age of erythrocyte isolates was determined from the cumulative distribution frequency of the cells in an isotonic (290 milliosmolar) density gradient and confirmed by assay for pyruvate kinase, an age-dependent red cell enzyme. An IBM 2997 centrifugal cell separator was used to obtain larger quantities of younger erythrocytes from normal subjects. 125I-insulin binding to red cells including reticulocytes was found to decrease exponentially as a function of their mean cell age in 8 normal subjects. A change in receptor number rather than affinity appeared to account for the observed change in 125I-insulin binding. An exponential, age-dependent change in binding of a hormone to its cell membrane bound receptor has not previously been observed. Consistent with these results is the possibility that regulation of the red cell insulin receptor concentration takes place only in the younger red cells.

Adult↗
PubMed1976

Isolation and characterization of aldose reductase from calf brain.

Aldose reductase activity (alditol: NADP+ 1-oxidoreductase, EC 1.1.1.21) from calf brain was separated into two protein fractions by DEAE chromatography. Further purifcation by molecular sieve chromotography and electrofocusing yielding two distinctive enzymes, which were designated AR I and AR II. AR I was purified 646-fold and found to have an isoelectric point of 6.18. AR I was most active as a monomer with a molecular weight of 29 000 and appeared to be in equilibrium with a less active dimer. AR II was purified 425-fold and found to have an isoelectric point of 4.88. The molecular weight of this enzyme was 30 000. Although both enzymes had specificity for aldoses as substrates, AR I had two to three times larger turnover numbers with aromatic aldehydes and hexonates than did AR II. AR I was activated by sulfhydryl compounds and exhibited biphasic double reciprocal plots. AR I was more sensitive to inhibition by high substrate and phenobarbital concentrations than was AR II. AR I and AR II did not have antigenic similarity as tested by Ouchterlony immunodiffusion and counter immunoelectrophoresis. An immunochemical cross-reaction was observed between AR II and lens aldose reductase.

Alcohol Oxidoreductases↗
PubMedDate not supplied

Interpretive reporting of laboratory data: proposed criteria to qualify as a high-quality, limited clinical pathology consultation.

OBJECTIVE: To present recommended criteria designed to improve the computer-based interpretation of laboratory test results. METHODS: Guidelines for providing high-quality test interpretations and an outline for incorporating such criteria into a program for interpretive reporting are presented. RESULTS: Traditionally, when a laboratory reports a test result, the clinician interprets it within the clinical context. More recently, even in the absence of clinical information about the patient, laboratories that report test results, including biochemical thyroid function tests, have begun to insert "informative" statements about the test. These statements fail to provide an adequate limited pathology consultation that merits the CPT code 80500. Such interpretations can be improved by making them optional, specific for the test result, considerations rather than recommendations, and accompanied, on request, by an expanded list of differential diagnoses and an itemization of drugs known to affect the test result. CONCLUSION: High-quality interpretations of laboratory tests should improve patient care, avoid unnecessary costs, and prompt appropriate referrals to specialists.

Journal Article↗