886
A.J.C.P. • November 1979
LETTERS TO THE EDITOR
Histochemical Demonstration of Leukocytic Acid Phosphatase To the Editor: — In a recent letter, Janckila and Yam 1 describe difficulties encountered by investigators with a method 2 for the histochemical demonstration of leukocytic acid phosphatase. These problems have been attributed to the purity of fast garnet GBC used as the coupling agent. This diazonium salt, which is prepared for Sigma, has been offered previously as a "practical grade" containing 25% fast garnet GBC. Following a query from Dr. Yam's
WILLIAM H. STARKWEATHER,
M.S.
R O N A L D L. SEARCY, P H . D .
Sigma Diagnostics Sigma Chemical Company St. Louis, Missouri 63118 References 1. Janckila AJ, Yam LT: Cytochemistry of tartrate-resistant acid phosphatase. Am J Clin Pathol 71:356-357, 1979 2. Janckila AJ, Li CY, Lam KW, et al: The cytochemistry of tartrate-resistant acid phosphatase. Am J Clin Pathol 70:45-55, 1978 3. Yam LT, Li CY, Lam KW: Tartrateresistant acid phosphatase isoenzymes in the reticulum cells of leukemic reticuloendotheliosis. N. Engl J Med 284:357-360, 1971
The Authors' Reply To the Editor: — In response to the letter by Mr. Starkweather and Dr. Searcy regarding fast garnet GBC, we are pleased to see that Sigma Chemical Company has recognized the clinical usefulness of tartrate-resistant acid phosphatase cytochemistry 6 and had taken steps to further purify its product. However, the increase in price for this purified reagerit has prompted us to investigate alternate sources for fast garnet GBC. Three companies other than Sigma were contacted and inquiries were made as to price, availability and purity of their fast garnet GBC. 3 - 5 Prices ranged from $8.50 per 100 grams to $8.00 per 25 grams, in contrast to $69.00 per 25 grams as quoted by Sigma Chemical Company for the purified reagent. Unfortunately, none of these companies could provide any information regarding the purity of its product. Two separate lots of fast garnet GBC Received and accepted for publication July 10, 1979. Address reprint requests to Dr. Yam.
were obtained from Roboz Surgical Instrument Company and tested for applicability for tartrate-resistant acid phosphatase cytochemistry. 1 One lot (6-76) proved to be satisfactory, whereas the other (3-78) caused the same inconsistencies as Sigma's lot 86C-0276, which we refer to in our original letter. 2 It appears that, rather than dye content, the most important criterion for an effective azo coupler is whether or not it contains enzyme inhibitors. As these dyes are manufactured primarily for industry, the scientific community has no control over production. Further, the Biological Stain Commission has no established protocol for certification of these dye stuffs for histologic application. It would be most advantageous if screening procedures could be devised to determine whether inhibitors are present in a particular lot of azo dye prior to its release to the customer by the scientific distributor. Until it can be determined which substances present in these products
may inhibit various enzymes and standard technics developed to test a particular azo coupler, we must suffer either the high price of purification and/or the possibility of obtaining a lot of material that proves to be unsatisfactory. ANTHONY J. JANCKILA L U N G T . YAM,
M.D.
Veterans Administration Medical Center Louisville, Kentucky 40202 References 1. Janckila AJ, Li CY; Lam KW, et al: The cytochemistry of tartrate-resistant acid phosphatase. 1. Technical considerations. Am J Clin Pathol 70:4555, 1978 2. Janckila AJ, Yam LT: Cytochemistry of tartrate-resistant acid phosphatase. Am J Clin Pathol 71: 356-357, 1979 3. Pfaltz and Bauer, Inc., Stamford, Connecticut 4. Polysciences, Inc., Warrington, Pennsylvania 5. Roboz Surgical Instrument Co., Inc., Washington, D. C. 6. Sigma Chemical Co: Technical Bulletin, No. 386, 1978
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
Received June 7, 1979; accepted for publication July 10, 1979. Address reprint requests to Dr. Searcy: Sigma Diagnostics, Sigma Chemical Company, St. Louis, Missouri 63118. Key words: Leukocyte acid phosphatase; Fast garnet GBC.
group in late 1977, it became evident that the product did not yield consistent results when used for this method of leukocytic acid phosphatase detection. The performance of the test, as described by Yam and co-workers, 3 was studied at Sigma using various lots of "practical grade" fast garnet GBC. Two lots (46C-0271 and 86C-0276) of the diazonium salt yielded poor results. Subsequently, the "practical grade" was purified to contain 70-80% diazonium salt. This material performed satisfactorily and is now available from Sigma Chemical Company as "Purified" Fast Garnet GBC Salt, Product No. F 6504, or as a component of the Sigma leukocytic acid phoshatase reagent system (Procedure No. 386).
A.J.C.P. • November 1979
LETTERS TO THE EDITOR
Histochemical Demonstration of Leukocytic Acid Phosphatase To the Editor: — In a recent letter, Janckila and Yam 1 describe difficulties encountered by investigators with a method 2 for the histochemical demonstration of leukocytic acid phosphatase. These problems have been attributed to the purity of fast garnet GBC used as the coupling agent. This diazonium salt, which is prepared for Sigma, has been offered previously as a "practical grade" containing 25% fast garnet GBC. Following a query from Dr. Yam's
WILLIAM H. STARKWEATHER,
M.S.
R O N A L D L. SEARCY, P H . D .
Sigma Diagnostics Sigma Chemical Company St. Louis, Missouri 63118 References 1. Janckila AJ, Yam LT: Cytochemistry of tartrate-resistant acid phosphatase. Am J Clin Pathol 71:356-357, 1979 2. Janckila AJ, Li CY, Lam KW, et al: The cytochemistry of tartrate-resistant acid phosphatase. Am J Clin Pathol 70:45-55, 1978 3. Yam LT, Li CY, Lam KW: Tartrateresistant acid phosphatase isoenzymes in the reticulum cells of leukemic reticuloendotheliosis. N. Engl J Med 284:357-360, 1971
The Authors' Reply To the Editor: — In response to the letter by Mr. Starkweather and Dr. Searcy regarding fast garnet GBC, we are pleased to see that Sigma Chemical Company has recognized the clinical usefulness of tartrate-resistant acid phosphatase cytochemistry 6 and had taken steps to further purify its product. However, the increase in price for this purified reagerit has prompted us to investigate alternate sources for fast garnet GBC. Three companies other than Sigma were contacted and inquiries were made as to price, availability and purity of their fast garnet GBC. 3 - 5 Prices ranged from $8.50 per 100 grams to $8.00 per 25 grams, in contrast to $69.00 per 25 grams as quoted by Sigma Chemical Company for the purified reagent. Unfortunately, none of these companies could provide any information regarding the purity of its product. Two separate lots of fast garnet GBC Received and accepted for publication July 10, 1979. Address reprint requests to Dr. Yam.
were obtained from Roboz Surgical Instrument Company and tested for applicability for tartrate-resistant acid phosphatase cytochemistry. 1 One lot (6-76) proved to be satisfactory, whereas the other (3-78) caused the same inconsistencies as Sigma's lot 86C-0276, which we refer to in our original letter. 2 It appears that, rather than dye content, the most important criterion for an effective azo coupler is whether or not it contains enzyme inhibitors. As these dyes are manufactured primarily for industry, the scientific community has no control over production. Further, the Biological Stain Commission has no established protocol for certification of these dye stuffs for histologic application. It would be most advantageous if screening procedures could be devised to determine whether inhibitors are present in a particular lot of azo dye prior to its release to the customer by the scientific distributor. Until it can be determined which substances present in these products
may inhibit various enzymes and standard technics developed to test a particular azo coupler, we must suffer either the high price of purification and/or the possibility of obtaining a lot of material that proves to be unsatisfactory. ANTHONY J. JANCKILA L U N G T . YAM,
M.D.
Veterans Administration Medical Center Louisville, Kentucky 40202 References 1. Janckila AJ, Li CY; Lam KW, et al: The cytochemistry of tartrate-resistant acid phosphatase. 1. Technical considerations. Am J Clin Pathol 70:4555, 1978 2. Janckila AJ, Yam LT: Cytochemistry of tartrate-resistant acid phosphatase. Am J Clin Pathol 71: 356-357, 1979 3. Pfaltz and Bauer, Inc., Stamford, Connecticut 4. Polysciences, Inc., Warrington, Pennsylvania 5. Roboz Surgical Instrument Co., Inc., Washington, D. C. 6. Sigma Chemical Co: Technical Bulletin, No. 386, 1978
Downloaded from http://ajcp.oxfordjournals.org/ by guest on June 5, 2016
Received June 7, 1979; accepted for publication July 10, 1979. Address reprint requests to Dr. Searcy: Sigma Diagnostics, Sigma Chemical Company, St. Louis, Missouri 63118. Key words: Leukocyte acid phosphatase; Fast garnet GBC.
group in late 1977, it became evident that the product did not yield consistent results when used for this method of leukocytic acid phosphatase detection. The performance of the test, as described by Yam and co-workers, 3 was studied at Sigma using various lots of "practical grade" fast garnet GBC. Two lots (46C-0271 and 86C-0276) of the diazonium salt yielded poor results. Subsequently, the "practical grade" was purified to contain 70-80% diazonium salt. This material performed satisfactorily and is now available from Sigma Chemical Company as "Purified" Fast Garnet GBC Salt, Product No. F 6504, or as a component of the Sigma leukocytic acid phoshatase reagent system (Procedure No. 386).
