[13. Elution velocity and elution profile of non specific esterase of cryostate sections of mouse kidney (author's transl)]

Peroxide treatment changes activity of non specific esterase in vascular endothelium of isolated pig aorta in vitro

The effect of hydrogen peroxide on certain enzymes contained in endothelial cells was investigated in vitro. Specifically in this study the influence of hydrogen peroxide on the non-specific esterase activity in endothelial cells of the perfused pig aorta was examined. We perfused an isolated segment of the pig aorta for 10 h and added 5, 10, 12, 15 ml 10% hydrogen peroxide to 100 ml perfused medium. In unperfused pig aorta 99.34% of the endothelial cells reacted positive. After 10 h of perfusion without hydrogen peroxide administration 93.25% endothelial cells still showed positive enzyme reactivity. In presence of hydrogen peroxide in the perfusion medium the activity of non-specific esterase was progressively inhibited, finally causing complete inactivation.

[Azoindoxyl methods for the investigation of hydrolases. II. Biochemical and histochemical studies of acid beta-galactosidase (author's transl)]

The determination of various reaction constants yields the following assay for the photometric evaluation of acid beta-galactosidase (measurement of the azoindoxyl dye at 540 nm after extraction with dimethylformamide or -acetamide): 1.5 mM 5-Br-4-Cl-3-indolyl-beta-D-galactoside (1 mg dissolved in 0.05 ml dimethylformamide) and 0.01-0.015 ml hexazotized p-rosaniline/ml in 0.1 M citric acid-phosphate buffer, pH 4. By means of this procedure it becomes evident that the activity of the enzyme differs considerably in various rat organs; NaCl does not influence acid beta-galactosidase. -- Similar results were obtained with the indigogenic method; indigo can be dissolved and measured photometrically as the azoindoxyl dye. The enzyme is suppressed by high concentrations of hexazotized p-roaniline to 50%; low concentrations do not inhibit; the same is true for ferricyanide-ferrocyanide employed in the indigogenic media. -- The effect of glutar- and formaldehyde on acid beta-galactosidase cannot be investigated with the azoindoxyl reaction since the azoindoxyl dye partially withstands extraction from fixed blocks of tissue. On the basis of the biochemical findings the azoindoxyl technique can be recommended for the histochemical demonstration of acid beta-galactosidase: 7.5 mg (1.5 mM) 5-Br-4-Cl-3-indolyl-beta-D-galactoside (dissolved in 0.25 ml dimethylformamide) and 0.05-0.15 ml hexazonium-p-rosaniline in 10 ml 0.1 M citric acid-phosphate buffer, pH 4. After incubation the sections can be treated with osmium tetroxide followed by dehydration and mounting in resins or can be mounted without prior osmification of the azoindoxyl dye in glycerin jelly. The osmium chelate resists treatment with organic solvents; the stability of the chelate depends on the concentration of hexazotized p-rosaniline. After fixation in glutaraldehyde or in a mixture of form- and glutaraldehyde acid beta-galactosidase can be exactly localized in the lysosomes of many rat organs. In comparison with the indigogenic, the metal precipitation and the simultaneous azocoupling reactions for the in situ detection of acid beta-galactosidase the azoindoxyl procedure is superior if fixed material is used; it is equivalent or inferior in connection with membrane technique. The biochemical azoindoxyl assay represents a useful method for combined qualitative and quantitative studies of acid beta-galactosidase.

Nonspecific acid esterase activity: a criterion for differentiation of T and B lymphocytes in mouse lymph nodes

A modified technique was used to demonstrate lymphocytic acid alpha-naphthyl acetate esterase activity in frozen sections of mouse lymphoid tissue or smears. Positive, dot-like reaction products were noticed in more than 94% of the lymphocytes located in the diffuse cortical ("paracortical", "thymus-dependent") area of mesenteric lymph nodes of young adult ICR mice. Almost identical values were found for lymphocytes in the cisterna chyli. In contrast, the follicular cortex which is predominantly occupied by B cells, contained less than 7% esterase-positive lymphocytes. In vitro, cytotoxic anti-theta serum destroyed the vast majority of esterase positive lymphocytes while esterase-negative lymphocytes were resistent to this treatment. In mesenteric nodes of nude BALB/c (nu/nu) mice, follicular cortex and paracortex together contained approximately 16 times less esterase-positive lymphocytes than in the immunologically competent hybrid BALB/c (nu/+) animals. These findings indicate that non-specific acid esterase activity may serve as a criterion to differentiate peripheral T and B lymphocytes in lymph node sections and smears of mice by light microscopy. Possible implications of this enzyme activity in thymus-derived lymphocytes are discussed.