Leucine aminopeptidase activity in blood and hemopoietic organs of different vertebrates. A histochemical comparative study

Leucine aminopeptidase distribution was examined in the cells of peripheral blood and hemopioetic organs of different Vertebrate classes using histoenzymatic methods. Various degrees of staining intensity were observed in leukocytes of the distinct Vertebrates: in particular, leukocytes of fresh water Osteichthyes and Mammals looked strongly positive, whereas leukocytes of Amphibians, Reptiles, and Birds were barely reactive without great differences among species. The observations should be related to enzyme molecular structure and to kinetics and substrate specificity.

Ultrastructural patterns of the alpha-naphthyl butyrate esterase activity in normal and leukaemic peripheral blood leucocytes

The activity of alpha-naphthyl butyrate esterase was investigated at the ultrastructural level in normal human peripheral blood and in a few cases of hairy cell leukaemia, B-chronic lymphocytic leukaemia and acute monocytic leukaemia. A membrane reactivity was detected in most normal monocytes and lymphocytes. The activity in monocytes was very strong and was inhibited by NaF. It was NaF-resistant and less intense in lymphocytes. The reaction product was localized in the cytoplasm only in a small percentage of lymphocytes. In lymphocytes and monoblasts from pathological samples the pattern of reactivity was similar to that found in their normal counterparts, except for a lower intensity. The hairy cells showed a discrete distribution of the NaF-resistant reaction product on their cell surface. The different patterns of enzyme distribution are discussed critically.

Morphohistochemical changes in hepatocytes during the life cycle of the European eel

The comparative analysis of morphological, histochemical and cytochemical patterns of eel (Anguilla anguilla L.) hepatocytes reveals clear differences between two stages of its life cycle, i.e. the trophic stage (yellow eel) and reproductive stage (silver eel). The storage of glycogen prevails in the yellow eel, whilst lipids appear to be remarkably increased in the silver eel, in which some hepatocytes also show glycogen-rich areas. Generally, in the silver eel dehydrogenase and acid phosphatase activities seem greater and different distribution of the reaction products is present; on the contrary, a lower G6PDH activity is observed. The electron microscopy characteristics and distribution of both cellular organelles and reserve materials reflect the modifications found at light microscopy. The ultrastructural patterns provide further evidence for the heterogeneity of liver parenchyma in silver eel. In particular, the coexistence of nuclei showing a different degree of chromatin compactness is also accounted for by the quantitative cytochemical data on the nuclear DNA after Feulgen reaction and intercalation with propidium iodide at low and high concentrations. With regard to the DNA content, the hepatocytes in the silver eel as well as in the yellow eel are mainly 2c. However, some 4c values are also found, which according to the literature can be ascribed to cells in G2 phase. The present data may express the onset of different functional requirements during the reproductive stage in comparison with the trophic one. Moreover, our results are consistent with modifications found by other authors as a consequence of interruption of nourishment and during gonad maturation, i.e. two phenomena characterizing the transition from yellow to silver eel.

Cytochemical study of K+-dependent p-nitrophenyl-phosphatase activity in the urinary bladder of Salamandra salamandra

The ultrastructural Na+-K+-ATPase localization in the salamander urinary bladder has been studied by the histochemical techniques of Ernst (1972) and Mayahara et al. (1980). Reaction products have been specially found on the basal and lateral membranes of granular and mitochondria-rich cells. The variable presence of artifacts, often accompanying Pb-capture phosphatase cytochemistry, is discussed. Additional data on the active ion transport have been obtained by using electrophysiological techniques.

Cytochemical pattern of alpha-mannosidase, alpha-fucosidase and neutral maltase in normal blood cells

The activity of alpha-mannosidase, alpha-fucosidase and neutral maltase was studied by cytochemical techniques in blood cells of 20 controls and of 4 T and B lymphocyte concentrates. All granulocytes, monocytes and platelets showed fine or coarse reaction product deposition, whereas lymphocytes were negative or showed various positivity patterns. A significant difference of the positivity between T and B subpopulations was observed only for the fucosidase reaction. It is possible that the different positivity patterns of the lymphoid cells are related to different functional activities. Further studies will probably confirm the interest of the alpha-fucosidase reaction for the characterization of normal and pathological lymphoid cells.

Comparative aspects of circulating erythrocytes in the trophic and reproductive phases of European eel. Ultrastructure and cytochemistry

Different cytochemical and morphological parameters were used to compare the functional patterns of the erythrocytes in the transition from the trophic (yellow eel) to the reproductive (silver eel) phases of European eel (Anguilla anguilla L.). Data on the nucleus were obtained by microdensitometric (Feulgen reaction) and cytofluoremetric (propidium iodide and Hoechst 33342 fluorochromization) evaluations of DNA staining intensity. In the silver eel, chromatin condensation was more heterogeneous and chromatin also appeared to be looser. The fluorochromes provided information on the different degrees of organization of the chromatin filament, with regard to both primary and higher order DNA structure. In the silver eel, the fine structure showed a higher number of erythrocytes with large euchromatinic areas and the heterochromatinic component was occasionally present in scattered clumps. As for the cytoplasm, in the silver eel a positive correlation could be established between the presence of intact cytoplasmic organelles (mitochondria, Golgi complexes, ribosomes, etc.) and the high fluorescence intensity. This aspect is revealed through the detection of definite membrane components such as glycoconjugates and primary amino groups (PAS reaction and fluorescamine staining, respectively). All these findings allowed us to establish that the transition from the trophic to the premigratory reproductive phase is marked by a higher heterogeneity of the erythrocytes, due to different cell maturation levels. This fact can be ascribed to different metabolic requirements as well as to a more intense erythropoiesis, typical of the most active phase of the eel's life.

Cytochemistry of cell surface sialoglycoconjugates in endometrial adenocarcinoma. Effects of medroxyprogesterone therapy

Ferritin- and rhodamine-conjugated Limulus polyphemus agglutinin was used to localize, by electron microscopy, and to quantify, by microfluorometry, the cell surface sialoglycoconjugates in human endometrial adenocarcinoma before and after medroxyprogesterone acetate therapy. In the untreated tumor the lectin labelling was irregularly distributed on the cell surface, with a maximum density at the apical area and at the intercellular border; high values of the density-binding sites on cell surface were also detected by cytofluorometry. The binding pattern in both electron microscopy and microfluorometry on normal tissue and on tumor tissue submitted to medroxyprogesterone acetate stimulation appeared clearly modified; the lectin labelling concerned the apical areas only (also after treatment with chelating agents), with low fluorometric values of the reactive site density. The differences found in the lectin binding to the cellular sialic acid residues may be due to sialoglycoconjugate quantitative changes and/or to their different reactivity resulting from alterations of the cell membrane architecture. The data appear also correlated with a different proliferative activity and ploidy level of the three situations analyzed.

Cytofluorometric study of the erythrocyte glycoconjugates content in different species of vertebrates

The PAS-positive material was measured by cytofluorometry in peripheral circulating erythrocytes of 22 species from different classes of Vertebrates. The following parameters were considered: total fluorescence intensity per cell, concentration index, fluorescence fading. The highest variability of concentration indexes was found in Fishes with a minimum in the more active swimmers (Scylliorhinus and Salmo); this fact may be related to a more intense erythropoiesis. The values were more homogeneous in the Amphibians, Reptiles, and Birds, the difference never exceeding 1/2 between the maximum and minimum values. The lowest concentration indexes were found in Mammals, a class with very specialized and enucleated erythrocytes: the data appear rather heterogeneous with a minimum in Macaca. The patterns of fluorescence fading suggest a biochemical homogeneity of the PAS-positive erythrocyte material in the species considered. This fact might indicate the presence of a fundamental biochemical component possibly linked to different structures of the red cells.

Propidium iodide as a probe for the study of chromatin thermal denaturation in situ

The possibility of using propidium iodide, a phenanthridinic fluorochrome specific for double-stranded nucleic acids, for the study of chromatin thermal denaturation in situ has been examined. Smears of lymphocytes and hepatocyte nuclei from 15-day-old rats were fixed in acetic acid--ethanol (1:3 v/v), treated with RNAse and submitted to different protein extraction procedures, namely, incubation with pepsin, trypsin and sodium chloride. Denaturation experiments were performed in Sörensen buffer at pH 7.4 containing 10% formamide at temperatures between 27 and 95 degrees C. The samples were stained with propidium iodide and mounted in buffer or glycerol. Measurements were performed with a microfluorometer at a wavelength of 446 nm. The results indicate a higher thermostability of lymphocytes as compared to hepatocytes. The denaturation pattern suggests a certain organization complexity of chromatin, better emphasized by the derivative curves which show the presence of at least three fractions with different melting points. After protein extraction, the denaturation curves exhibit a somewhat simplified pattern, with the disappearance of the most stable peak in the derivative curves. The samples mounted in glycerine exhibit a better stability of staining with time, and an increased quantum efficiency of the fluorochrome with regard to those mounted in buffer. These data confirm the importance of protein--DNA interactions in the organization of chromatin and point to some differences, depending on the cell type and on functional activity.

[Histochemical demonstration of tetrahydrofolate dehydrogenase in human bone marrow: apparent enzymatic induction after administration of folic acid antagonists]

Folate antagonists interfere to a varying extent with the histochemical demonstration of tetrahydrofolate dehydrogenase. Some aspects of this interaction are investigated in normal hemopoietic cells of patients following antitumor treatment with methotrexate. In this situation the histochemically detectable activity of tetrahydrofolate dehydrogenase exceeds the control levels (apparent enzymatic induction). A protection of the enzyme-metabolite complex from degradation and diffusion might be effective for the changes in reaction intensity.

Tetrahydrofolate dehydrogenase in blood cells and in hematopoietic organs of different vertebrate species

Some general aspects in cytochemical demonstration of the tetrahydrofolate dehydrogenase, concerning the final reaction product, are studied. Steady and variable factors are detected in a comparative study of Vertebrate hemopoiesis: the enzyme exhibits peculiar features in different cell types. The reactivity progressively decrease in the erythropoietic series, in concomitance with hemoglobin synthesis. Conversely an increase in the intensity of reaction is found in the granulocytopoietic series; the correspondence of positive material with the specific (eosinophil and heterophil) granulations can be discussed. The thrombocytopoietic series is also labelled by this reaction.

Changes in liver cells ploidy of young rats following isoprenaline treatment

Cell proliferation induced by isoprenaline (IPR) stimulation in very high doses was assayed in the liver of young rats, and the formation of polyploid cells was studied form the 15th to the 70th day of life. A general stimulatory effect on a complex process of cellular multiplication, leading to a population of tetraploid cells, was found to be accelerated; the earlier appearance of binucleate cells and the subsequent significant variations in their incidence confirmed the role of this cell type as an intermediate step in the process of polyploidization. Evidence was found of concomitant size changes of the hepatocytes, which might be partially independent of the effect of DNA content. The stimulation was no longer evident 20--30 days from the end of treatment, by when the cells which had come into contact with IPR should have completed the whole sequence of events leading to the formation of tetraploid mononucleate cells.

The sulfatides and some histochemical correlations of the lachrymal glands involved in salt secretion in Chelonia

High concentrations of sulfolipids (four fractions having different hexose/sulfate ratio), intense enzyme activity (ATPase, oxoreductases) and evidence of mucines (staining with PAS and Alcian blue) in intercellular spaces were found in the lachrymal glands of Caretta caretta and Malaclemys terrapin adapted to sea water. In addition, the supranuclear region of the gland cells in Malaclemys terrapin is filled with mucin granules. These biochemical and histochemical observations indicate that these glands have a function in salt secretion in both species and are also consistent with a function of mucous secretion exclusively in Malaclemys terrapin. Limited signs of hypotrophy are not accompanied by changes in concentrations of sulfolipids in Malaclemys terrapin adapted to fresh water; only the reactions for enzyme activities are less intense. The mucous secretion is not affected, whereas, in correlation with changes in salt secretion, the change in ATPase activity is mot conspicuous. The correlations between the different components of the gland and salt secretion are compared with salt glands of birds and elasmobranchs.