A procedure to measure concanavalin-A binding with atomic spectroscopy and X-ray microanalysis

Summary

The purpose of this study was to measure the binding of concanavalin A (conA) in minute regions of tissue by labelling the conA with iron dextran; then by measuring the bound iron per site by a procedure which uses atomic absorption spectrophotometry, X-ray microanalysis, and image analysis. The resulting data for a given region γ are entered into the formula:

$${\text{iron at }}\gamma {\text{ = }}\left( {\frac{{{\text{Fe K}}\alpha {\text{X - rays from }}\gamma }}{\begin{gathered} {\text{Sum of Fe K}}\alpha {\text{ x - rays}} \hfill \\ {\text{ from all regions}} \hfill \\ \end{gathered} }} \right) \left( {\frac{{{\text{Area of }}\gamma }}{\begin{gathered} {\text{Sum of all}} \hfill \\ {\text{ areas}} \hfill \\ \end{gathered} }} \right) \left( \begin{gathered} {\text{Total iron}} \hfill \\ {\text{in section}} \hfill \\ \end{gathered} \right)$$

The resulting quantity “iron at γ” is directly proportional to conA binding in that region.

For this study, three regions of rat renal cortex were compared: (1) distal tubules, collecting ducts and blood vessels; (2) glomeruli; and (3) proximal tubules.

Regional iron concentrations were: (1) Combined region (distal tubules, etc.), 0.147±0.107 μg/mg tissue; (2) glomeruli, 0.199±0.087 μg/mg tissue; and (3) proximal tubules, 1.711±0.303 μg/mg tissue.