Lead citrate method of guanylate cyclase and its application to tissue receiving rapid freeze substitution fixation.

Histochemistry of Cyclic Nucleotide Metabolizing Enzymes in Osteoarthritis.

“…Later, biochemical studies showed the degree of non-enzymatic break-down was not as high as had been reported [6,7,10]. A new capture agent of lead citrate was introduced showing that it is a better capture agent than lead nitrate [43].…”

“…However, biochemical experiments made later proved the inhibitory action of lead as well as that catalytic action on the substrate was not so great as they had stated [6,7,10]. The introduction of lead citrate, instead of lead nitrate, in the demonstration of ACase also decreased the anxiety on the cytochemical method of ACase [42,43].…”

“…The introduction of a histochemical method for GCase was first made by Saito et al (1992) [43] introducing guanylyl imidodiphosphate (GMP-PNP), giving lead citrate as the capture agent and bromotetramisole oxalate as the inhibitor of alkaline phosphatase, because the medium is rather high in pH, which may induce the contamination of alkaline phosphatase.…”

“…Then 40 ~cm frozen or non-frozen sections were made with a freezing microtome (Komatsu Electronics, Tokyo, Japan) or a Microslicer (Dosaka EM, Kyoto, Japan). Sections were incubated in a medium (Saito et al, 1992) [43]. For 5'-nucleotidase, the medium of Wachstein and Meisel (1957), consisting of a 20 mM Tris-maleate buffer, pH 7.2, 0.5-1.0 mM adenosine-5-monophosphate, 3.6 mM lead nitrate, 10 mM magnesium sulfate was applied [47].…”

“…However, most past studies have been limited to light microscopy so that the ultrastructural cytochemistry is limited [19,25]. The purpose of this report is to describe the cyclic nucleotide metabolizing enzymes, such as adenylate cyclase (ACase) [42], guanylate cyclase (GCase) [43], and 5'-nucleotidase (5'-N) [47], by focusing on the function of the synovial membrane in osteoarthritis cytochemically.…”