Biomedical subjects

Z Lojda

Publications and source records attributed to Z Lojda.

At least 181 records · Page 10Linked to original sources

PubMed1975

The use of hexazonium-p-rosanilin in the histochemical demonstration of peptidases.

The suitability of hexazonium-p-rosanilin (HP) in the histochemical demonstration of peptidases was investigated. The detection was carried out in cold mictrotome sections adherent to slides or semipermeable membranes. Alanyl-1-naphthylamide, alanyl-2-naphthylamide, leucyl-2-naphthylamide, leucyl-4-methoxy-2-naphthylamide (all substrates in concentration of 0.4 mg/1 ml of citrate phosphate buffer pH 6.5), gamma-L-glutamyl-1-naphthylamide, gamma-L-glutamyl-2-naphthylamide (both substances in concentration of 0.24 mg/1 ml of acetate buffer pH 6.5) were used as the substrates. Results were compared with those obtained with Fast Blue B and Fast Garnet GBC. In comparison with Fast Blue B and Fast Garnet GBC HP is a faster coupler, furnishes azodyes which are stable, amorphous (even without lipid extractions from sections), more substantive and in the case of 1-naphthylamine almost insoluble in ordinary lipid solvents used for the dehydration and clearing of sections before mounting. The molecular extinction coefficient of azodyes furnished by HP is 1.5X higher for 1-naphthylamine than for 2-naphthylamine. It is higher than that of Fast Garnet GBC, however, lower than that of Fast Blue B. The inhibitory influence of individual diazonium salts on enzyme activity (activities) splitting leucyl-2-naphthylamide amounts to 36% (Fast Garnet GBC), 37% (Fast Blue B), 52% (HP, 0.03 ml/1 ml) and 63% (HP, 0.09 ml/1 ml) at pH 6.5. For gamma-glutamyl-transpeptidase the corresponding values are 50%, 59%, 62% and 67%. The higher inhibitory influence of HP is compensated by the possibility of its using in the technic of semipermeable membranes. HP improves greatly the localization of peptidases in cold microtome sections from which lipids were not extracted. The best results are furnished by 1-naphthylamine dervatives. In the case of 4-methoxy-2-naphthylamine derivatives the localization is very sharp, however, the azodye is less distinct than that of 2-naphthylamine. The localization as obtained with HP in combination with substrates derived of simple naphthylamines is similar or even better than with 4-methoxy-2-naphthylamine derivatives applied with Fast Blue B. Typical examples are shown.

1-Naphthylamine↗

PubMed1975

Distribution of acid phosphatase, beta-glucuronidase, n-acetyl-beta-d-glucosaminidase and beta-galactosidase in cornea of albino rabbit.

Activities of acid phosphatase, beta-glucuronidase, N-acethyl-beta-D-glucosaminidase and acid beta-galactosidase were investigated histochemically in rabbit corneas. Frozen sections after block fixation in cold 4% formaldehyde with 1% CaCl2 followed by washing in cold physiological saline as well as cold microtome sections of corneas quenched in petroleter chilled with acetone-dry ice mixture, transferred to nonprecooled slides or semipermeable membranes were used. Standard aqueous media were employed in the case of free-floating frozen sections of fixed corneas as well as of cold mictrotome sections (postfixed in cold 4% formaldehyde). Agar media were used in connection with the technic of semipermeable membranes. Gomori method (in the case of acid phosphatase), simultaneous azocoupling methods (substrates derivated of naphthol-AS-BI with hexazonium-p-rosanilin) in the case of acid phosphatase, beta-glucuronidase and N-acetyl-beta-D-glucosaminidase and the indigogenic method in the case of acid beta-galactosidase were applied. Enzyme activities in sections of fixed corneas were minimal in comparison with those in cold microtome sections of unfixed material revealed particularly with the technic of semipermeable membranes which is to be preferred. This technic is recommended in studies concerned with lysosomal enzymes in the cornea, particularly in keratocytes. All enzymes investigated were present in corneal epithelium, keratocytes and endothelium. Acid phosphatase displayed the highest activity followed by beta-glucuronidase and acetyl-beta-D-glucosaminidase. The activity of beta-galactosidase was the lowest. For the demonstration of activities in keratocytes sections parallel to the surface are very suitable. In these sections enzyme activities were demonstrated in small granules (apparently lysosomes) present in the central part of their cytoplasm as well as in projections. Diffuse staining was also seen, being the highest in the case of acid phosphatase.

Acetylglucosaminidase↗

PubMed1975

Alkali burns of the rabbit cornea. I. A histochemical study of beta-glucuronidase, beta-galactosidase and N-acetyl-beta-D-glucosaminidase.

In alkali burned rabbit corneas activities of beta-glucuronidase, N-acetyl-beta-D-glucosaminidase and acid beta-galactosidase were studied histochemically in various time intervals after the traumatization. The technic with semipermeable membranes was employed. Within four days after the injury enzyme activities in the traumatized area were almost lacking. The corresponding activities in the unaffected part of the cornea were within the norm. On the 7th day enzyme activities were on an increase (but still subnormal) in the traumatized area. This area was surrounded by a zone of keratocytes with high levels of enzyme activities. This was particularly remarkable in keratocytes subjacent to the epithelium. The activation of all enzymes studied was present in the basal layer of the epithelium and in the endothelium as well. On the 14th day enzyme activities in the traumatized area were nearly restored and on the 32nd day they could not be distinguished from the normal cornea. Beta-galactosidase displayed a relatively maximal increase in the activity of all enzymes investigated.

Acetylglucosaminidase↗

PubMed1975

Alkali burns of the rabbit cornea. II. A histochemical study of glycosaminoglycans.

In alkali burned rabbit cornea the stainability of glycosaminoglycans in cold microtome setions was investigated. Staining by Alcian blue in 3% acetic acid, Alcian blue in various MgCl2 concentration and toluidine blue (pH 4.5) was employed. From the 1st to the 4th experimental day the intensity of reactions was decreased. This is most probably due to an increased hydration of the corneal stroma. On the 7th day hydration was markedly suppressed and reached nearly the normal level. In this time interval a decreased stainability of glycosaminoglycans was seen accompanied by a complete loss of staining in the marginal zone. On the 14th day the stainability in the traumatized area began to restore and in the marginal zone appeared. On the 32nd day the staining intensity of both areas was normalised, however when lower concentrations of MgCl2 were used; in the presence of higher concentrations of MgCl2 the decreased staining intensity persisted and points to a lower sulfatation of glycosaminoglycans. This was particularly remarkable in the area bordering the injured zone. This decrease runs parallel to the increased activities of acid glycosidases (especially of acid beta-galactosidase) which were reported previously.

Alcian Blue↗

PubMed1975

Suitability of the azocoupling reaction with 1-naphthyl-beta-D-glucoside for the histochemical demonstration of lactase (lactase-beta-glucosidase complex) in human enterobiopsies.

The suitability of the simultaneous azocoupling reaction with 1-naphthyl-beta-D-glucoside and hexazonium-p-rosanilin in the detection of the activity of lactase (or lactase-beta-glucosidase complex) in jejunal biopsies of patients with various forms of the malabsorption syndrome was tested. Results were compared with those obtained with the indigogenic method using 4-Cl-5-Br-3-indolyl-beta-D-fucoside which is the method of choice. Both methods gave identical results as far as the relative intensity of the brush border staining was concerned. The azocoupling method applied in unfixed cold microtome sections can be recommended for the routine diagnostics of the malabsorption syndrome when the indolyl substrate is not available.

Adult↗

PubMed1975

The histochemical demonstration of aminopeptidase with bromoindolyl leucinamide.

The indigogenic method for aminopeptidase of Pearson et al. (1963) was critically evaluated. The localization obtained with it is not correct due to diffusion artifacts. Ferricyanide cannot be used as an oxidation agent. Based on experiments with other oxidation agents (phenazonium methosulfate, nitro BT, tetranitro BT) a new method was devised. The recommended incubation medium contains 0.9 mM L-N-(5-bromoindol-3-yl) leucinamide hydrobromide (chloride), 0.73 mM tetranitro BT, 0.27 mM phenazonium methosulfate and 0.67 M phosphate buffer pH 7.4. The enzyme activity is indicated by the deposition of tetranitro BT formazan. Results with this method in rat kidney, jejunum, liver, lung, and submaxillary gland, in monkey kidney and jejunum, and in human jejunal biosies are almost identical with those obtained with L-leucyl-4-methoxy-beta-naphthylamide applied in a simultaneous azocoupling procedure. The given principle of the demonstration of aminopeptidase activity with an indolylamine substrate deserves a further exploration in the demonstration of peptidases "in situ" both on optical as well as electronmicroscopical levels.

Aminopeptidases↗

PubMed1975

[Jejunal mucosa in children with mucoviscidosis].

Thirty-eight specimens obtained by jejunal biopsy from 22 children suffering from mucoviscidosis were examined by histochemical techniques. In 27% of the patients the findings were within normal limits. In 18% of cases, associated coeliacal sprue was disclosed. The remaining cases displayed slight morphological abnormalities associated with trehalase and/or lactase deficiency, and in 41% there was hypersecretion of viscous mucus filling up dilated crypts and adhering to the surface of villi. The findings as observed in enterobiopsis are not pathognostic of mucoviscidosis. They however, should make one to think of it, particularly if trehalase and/or lactase deficiency is found associated with hypersecretion of viscous mucus and an almost normal morphological appearance. Neither normal findings nor that of coeliacal sprue exclude the diagnosis of mucoviscidosis. It appears that malabsorption in mucoviscidosis is not only pancreatogenic; the intestinal mucosa may be contributory to a various degree as well.

Biopsy↗

PubMed1975