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T E Mifflin

Publications and source records attributed to T E Mifflin.

22 records · Page 2Linked to original sources
PubMed1985

University of Virginia case conference. Macroamylase, macro creatine kinase, and other macroenzymes.

The importance of macroenzymes has become increasingly apparent in recent years (1,2). Macroamylase (EC 3.2.1.1) and macro CK (EC 2.7.3.2) are the macroenzymes most commonly noted in the clinical laboratory, and they are frequently responsible for diagnostic confusion. Several methods are available for the confirmation and analysis of macroenzymes, many of which require expensive equipment or complicated techniques. In this report we summarize two cases of macro creatine kinase and two cases of macroamylase that illustrate the clinical importance of recognizing these macroenzymes. We review the features of these macroenzymes, discuss their laboratory evaluation, and describe a simple method that we have used to detect the macroenzymes in these (and other) patients at our institution. Finally, we review the literature on other, less commonly observed macroenzymes in human blood. We stress (a) the impact of methodology on clinical impressions and (b) the importance of discussing laboratory observations with the patient's physician and communicating them to the patient's medical record in writing.

5'-Nucleotidase↗
PubMed1985

Rapid quantitative, specific measurement of pancreatic amylase in serum with use of a monoclonal antibody.

In this rapid quantitative assay for pancreatic alpha-amylase (EC 3.2.1.1) in serum, we precipitate salivary amylases by 10-min incubation with monoclonal anti-salivary amylase antibody immobilized on particles of polyvinylidene fluoride. We then centrifuge the serum mixture and measure the pancreatic amylase activity remaining in the supernate by a kinetic method. The assay requires 50 microL of serum and the standard curve is linear to at least 1300 U of pancreatic amylase per liter of serum. CVs were 1.3% within-run, 6-8% day-to-day. Apparent analytical recovery of pancreatic amylase activity added to serum was 101% +/- 2%. Addition of purified salivary amylase, 356 U/L, to sera gave a value for apparent pancreatic amylase of less than 4 U/L, or 1% of the added salivary amylase activity. This assay correlated well with an electrophoretic method (slope, 0.97-0.99; intercept, 0.5 to -4 U/L; correlation coefficient, 0.946-0.990; and standard error of the estimate 3-5 U/L). Estimated normal reference intervals with maltotetraose as substrate were: total amylase, 39-118 U/L; pancreatic amylase, 11-50 U/L; and salivary amylase, 18-79 U/L.

Antibodies, Monoclonal↗
PubMed1983

Calorimetric studies of flavin binding protein: flavin analog binding.

The effect of flavin structure variation upon the overall binding reaction of flavin to hen egg white riboflavin binding protein (WRBP) was correlated to thermodynamic parameters obtained via titration calorimetry. This effect was measured by determining a reference binding enthalpy (delta Href) for 3-carboxymethylriboflavin and subsequently comparing delta Href to the binding enthalpies determined for all other flavin analogs in this study. The reference enthalpy change was measured in detail under a variety of temperatures (14, 25, and 38 degrees C), pH's (5.5, 6.5, 7.4, 8.5), and buffer types. The reference enthalpy for the binding of N(3)-carboxymethylriboflavin to WRBP was measured as delta H = -20.9 kcal/mol at 25.0 degrees C and pH 7.4. Evaluation of the binding thermodynamic values for the reference flavin indicates that there is no H+ flux concomitant with binding. A small negative change in heat capacity (delta Cp) occurs during the binding process suggesting a contraction of the protein. Finally, the reaction appears to be independent of pH and buffer type indicating little, if any, involvement of charged residues in the binding of flavin to apoWRBP. Thermodynamic values for the binding of an additional eight flavin analogs were then measured at pH 7.4 and 25.0 degrees C. The thermodynamic binding parameters for these analogs were evaluated by comparison to those determined for the reference flavin. The results indicate that the ribityl C2' position is a major influence in the interaction between the ribityl side chain and the protein; the C9 position of the isoalloxazine ring is sterically restricted in a manner similar to positions C7 and C8; and the positions C7 and C8 appear to be unequal with regard to enthalpy release, suggesting that the C8 position is the most restricted region in the aromatic ring. These various findings indicate the unique ability of titration calorimetry to evaluate structural variation of ligands to their corresponding binding site interactions.

Animals↗