Influence of bone staple design on interfragmentary compression.

Staple fixation, most commonly thought of as static, has been studied with regard to effecting dynamic compression. Features of staple design that relate to the creation of interfragmentary compression have been analyzed, and a simple manipulative technique to effect compression is illustrated. Compressive forces of bone fixation staples were measured using pressure-sensitive film. Thirteen staple designs were tested in a wood-block model and in cadaveric bone. Staples with legs splayed outward produced higher compressive forces than standard staple designs. Internal beveling of the staple leg tips also produced high compressive forces, while external beveling produced distraction. Staples with legs tapered over their entire length produced compression, but caused splitting in the wood-block model. Our results show that outward splaying of the staple legs is a simple method to increase compression in any staple design.

Aminophenylboronic acid affinity chromatography and thiobarbituric acid colorimetry compared for measuring glycated albumin.

Two techniques originally developed for measurement of glycated ("glycosylated") hemoglobin but also applicable to determination of glycated albumin are the thiobarbituric acid colorimetric technique (I) and the aminophenylboronic acid affinity chromatographic procedure (II). The latter reliably distinguishes diabetics from nondiabetics, and concentrations of glycated hemoglobin and glycated albumin are linearly correlated. I is nonspecific; it neither correlates with diabetic status nor with values derived via the affinity technique. Most of the chromogenic material is present in the fraction of albumin that does not bind to aminophenylboronic acid. Glucose interferes significantly with I but only slightly with II. Prolonged incubation of plasma with glucose dramatically increases the II-determined glycated albumin. Reactivity with thiobarbituric acid increases much less, and mainly in the II-bound fraction. This fraction contains a high proportion of nonspecifically reactive material. The percentage of glycated albumin determined in crude plasma samples by II differs only slightly from the value determined by purifying the albumin from the plasma. This technique appears more promising than I for eventual clinical applications.

Use of aminophenylboronic acid affinity chromatography to measure glycosylated albumin levels.

A simple technique for the measurement of glycosylated albumin by affinity chromatography on m-aminophenylboronic acid agarose columns is presented. The technique relies on bromcresol green determination of albumin in the nonbound and bound fractions. There is a linear correlation between albumin concentration of the bound fraction and glycohemoglobin values in individuals. A control nondiabetic plasma pool with a glycohemoglobin value of 7.10% +/- 0.05% (mean +/- SEM) had a glycoalbumin value of 1.64% +/- 0.06%, while a diabetic control plasma pool with a glycohemoglobin value of 13.63% +/- 0.07% had a glycoalbumin value of 4.02% +/- 0.12%. Compared with results from the affinity technique, the preponderance of colorimetric reaction determined with the thiobarbituric acid procedure is nonspecific, in that it does not correlate with diabetic status or with values derived by the affinity procedure. The bulk of thiobarbituric acid-reactive material is present in the fraction of albumin that does not bind to aminophenylboronic acid. This nonbound fraction contains plasma glucose, which significantly interferes with thiobarbituric acid determinations but only very slightly interferes with the affinity procedure. Prolonged incubation of plasma with 500 mg/dl glucose dramatically increases affinity-determined glycosylated albumin. Thiobarbituric acid reactivity increases much less, the increase being mainly in the fraction bound to aminophenylboronic acid. The percentage glycosylated albumin determined by the affinity technique in crude plasma samples differs very slightly, if at all, from that determined by purification of the albumin from plasma. The affinity technique appears very promising for eventual clinical applications in the management of diabetes.