This study was undertaken to evaluate a use of the dinitrosalicylic acid (DNS) reaction in places of the jodometric and the Somogyi's saccharogenic methods which had been conventionally used for measuring serum amylase activity in spite of its advantage and disadvantage of the each method in regards to simplicity of the procedures and accuracy of the results. As a result, it was concluded that the modified dinitrosalicylic acid method was suitable as a routine clinical test for determining the saccharogenic activities of human serum and pancreatic juice. 1) The following assay conditions in the DNS method were found suitable; 25 times in dilution of normal human serum, 104 times in that of pancreatic juice and 30 minutes for duration of incubation of the both materials. 2) The calibration formulas were derived, which permitted to converse amylase activities of human serum and pancreatic juice obtained by the DNS method. 3) Amylase activities determined by the DNS method were found to be not influenced by clinically usual contents of serum protein and blood sugar. 4) Serum amylase activity levels in 50 normal human determined by this method ranged from 59 to 141 Somogyi units. Changes with more than 30 units were considered to be significant.
Five cases of esophageal carcinoma, two of esophageal leukoplakia and one of carcinoma of tongue were investigated enzyme-histochemically. Enzymes studied in the study were alkaline phosphatase, acid phosphatase, β-esterase, aminopeptidase and β-glocuronidase as hydrolytic enzymes, and succinic dehydrogenase, lactic dehydrogenase, malic dehydrogenase, α-glycerophosphate dehydrogenase glutamic dehydrogenase, βhydroxybutyric dehydrogenase, glucose-6-phosphate dehydrogenase and isocitric dehydrogenase as oxidative enzymes. The activity of alkaline phosphatase and aminopeptidase were negative in squamous cell carcinoma, but occasionally positive in stromal element, especially in that of infiltrating carcinoma. Succinic dehydrogenase activity of normal esophageal epithelium was stronger in basal cell layer than in keratinized layer. Other NAD dependent enzymes of it showed a similar tendency. On the other hand the activity of NADP dependent glucose-6-phosphate dehydrogenase of it was stronger in keratinized layer than in basal cell layer. Generally, these squamous cell carcinomas appeared weak enzyme activity, but glucose-6-phosphate dehydrogenase activity was rather stronger than other enzymes. Some infiltrating marginal area and small cell nestle of carcinomas showed rather strong activities of succinic, β-hydoxybutyric and malic dehydrogenases, also pearl formation revealed moderate activity of glucose-6-phosphate dehydrogenase. Enzymatic activity in stromal element of all cases was very weak.