Bengt Arborgh

Giant cell tumor of bone

The fine structural localization of nonspecific alkaline phosphatase was elucidated in two giant cell tumors of bone using lead as capturing ion and Β-glycerophosphate as substrate in the incubation solution. Lead phosphate precipitate — indicating presence of alkaline phosphatase — was demonstrated on the plasma membranes, and the membranes bordering vesicles and vacuoles of presumed endocytotic nature, in giant cells and type 1 stromal cells (fibroblast-like cells). The findings support the view that stromal cells type I and giant cells are histogenetically related.

Giant cell tumor of bone. Variations in patterns of appearance of different cell types.

Eleven benign giant cell tumors of bone were studied in the electron microscope, and the fine structural localization of acid phosphatase was elucidated. Three distinct cell types are always present in these tumors: stromal cells type 1; stromal cells type 2; and multinucleated giant cells. Small mononuclear cells may also occur, but are not likely to be actively participating in the neoplastic process. The range of variability in the fine structure of the different cell types constituting this tumor has been established. Variations in appearances include: a) presence of nuclear pseudoinclusions in stromal cells type 1 and multinucleated giant cells; b) aberrations in the structure of the rough surfaced endoplasmic reticulum in the same cell types; c) occurrence of ruffled borders, ectoplasmic layers and cytoplasmic labyrinths containing acid phosphatase in the giant cells. Some giant cells show evidence of marked phagocytic activity and contain large and numerous residual bodies carrying acid phosphatase. The significance of the interrelations between the different cell types are discussed and the possible role of stromal cells type 2 in immunological mechanisms directed against the tumor cells are mentioned.

Studies on the fine structure of osteoblastoma with notes on the localization of nonspecific acid and alkaline phosphatase.

Electron microscopy of two osteoblastomas revealed the existence of three distinct types of cells in this tumor: osteoblast like, macrophage like, and multinucleated giant cells. In addition to the lysosomes, most Golgi cisternae and vesicles in the osteoblast like cells showed evidence of acid phosphatase activity. Deposits of lead phosphate indicating the site of this enzyme in the macrophage like cells were confined to the large and abundant lysosomes. Wide spread deposition of final product was noted in the cytoplasm of the multi‐nucleated giant cells, both in conventional lysosomes, Golgi regions and special organelles probably corresponding to GERL. With regard to nonspecific alkaline phosphatase, final product indicating the location of enzyme activity was confined to the plasma membranes and associated vesicular and vacuolar structures in the osteoblast like cells. The findings suggest that the giant cells in osteoblastomas participate in lytic bone destructive and resorptive processes while osteoblast like cells appear to be osteoid and bone forming carriers of the neoplastic properties of the tumor.

Quantitation of acid phosphatase and aryl sulphatase in rat hepatic parenchymal and kupffer cells

The two acid hydrolases ‘acid phosphatase’ (orthophosphoric monoester phosphohydrolase, EC 3.1.3.2) and ‘aryl sulphatase’ (aryl-sulphate sulphohydrolase, EC 3.1.6.1) are both enzymes which are known to be present in the lysosomes of almost all cell types [cf. l] . Histochemical studies have revealed apparent activity of acid phosphatase in both hepatic parenchymal and Kupffer cells [2,3] , and parenchymal liver cells have been claimed to show enzyme activity in granular form as revealed by light microscopy of sections incubated at pH 5 5 [4] ; however, histochemical methods have so far failed to reveal the situation in the Kupffer cells [5] . Evidence from studies of other tissues have suggested that lysosomes are heterogeneous with regard to content of lysosomal enzymes, and it has been claimed on the basis of results of histochemical studies that the distribution of aryl sulphatase may not completely agree with the distribution of acid phosphatase [4,6] . Furthermore, higher purification of aryl sulphatase than for instance acid phosphatase was obtained in lysosomes isolated from rat liver [7] . Methods have recently been worked out for the separation of parenchymal and Kupffer cells in highly purified fractions of rat liver [8-lo]. In the present study these methods were utilized with the aim of elucidating and comparing the activities of aryl sulphatase and acid phosphatase in the two main cell types of the liver.

Isolation of Kupffer cell lysosomes, with observations on their chemical and enzymic composition☆

Abstract The purpose of the present investigation was twofold: The isolation of Kupffer cell lysosomes by changing their density in vivo through uptake of colloidal silver iodide (Neosilvol R ), and the characterization of the isolated fraction. No significant changes in the activities or distribution of acid phosphatase, aryl sulphatase, and cathepsin D were found after the injection of Neosilvol R . A method is presented for the isolation of silver-loaded lysosomes from rat liver Kupffer cells by means of ultracentrifugation in sucrose gradients. Morphological and biochemical data indicate that the lysosomal fraction was contaminated with other subcellular organelles only to a minor degree. The lysosomal fraction showed non-parallel enrichment of various acid hydrolases, with the highest degree of purification found for aryl sulphatase and the lowest for acid phosphatase. The lysosomal enzyme activity pattern was similar to that found in Kupffer cell preparations.

Histochemical and biochemical studies on the localization and activity of lysosomal enzymes in fracture callus

SummaryQuantitative biochemical studies on the activities of four lysosomal hydrolases during different stages of fracture healing in the rat were performed, and the results obtained were integrated with those of histochemical observations relating to changes in the localization of acid phosphatase in the same tissue.The findings showed presence of all the four lysosomal enzymes assayed in the callus; during early callus formation the enzyme activities calculated on a DNA basis increased up to about 12 days after the fracture. The enzyme activities appeared to be roughly reflected histochemically by the acid phosphatase staining. The increasing activity during early callus formation seemed to depend on the presence of numerous macrophage-like cells in the tissue containing many large lysosomes. A decrease in enzyme activity was found after day 12. Comparison with the histochemical and ultrastructural findings suggested that this decrease was due to a reduction in the number of macrophage-like cells and a concomitant increase in osteogenic cells with a lower enzyme content.

Malignant giant cell tumor of bone

The fine structure of the different cell types constituting a primary malignant giant cell tumor of bone has been studied and the localization of acid phosphatase in relation to the subcellular organelles been demonstrated. Three distinct cell types with characteristic ultrastructural features were observed: giant cells, fibroblast-like cells, and cells with abundant lipid inclusions and mitochondria. Certain differences were noted between these three cell types and their counterparts in benign giant cell tumors of bone (described in a separate report). The enzyme histochemical and morphological data suggested that the giant cells in the malignant tumor might possess a more active and expansive lysosomal apparatus than corresponding cells in the benign variant.

Induction of liver lysosomal enzymes during the autophagic phase following phenobarbital treatment of rat

SummaryPhenobarbital was given to male rats as a single injection and as repetitive injections for 7 days. The effects of treatment on the lysosomal hydrolases acid phosphatase, cathepsin D, and aryl sulfatase were analyzed at different intervals ranging from 1 to 15 days after seven injections, and from 1 to 48 h after a single injection. In both cases, microsomal protein and NADPH-cytochromec reductase were measured to ensure proper induction. After a single injection, a slight decrease in hydrolytic activities was observed. Repetitive administration of phenobarbital gave rise to a marked decrease of lysosomal enzyme activities 1 day after cessation of treatment. This decrease was followed by a continuous increase in activity up to day 3 and 4. One or 2 weeks after treatment, enzyme activities declined to control values. The increase in activity of lysosomal hydrolytic enzymes was correlated with the onset of induced autophagy of endoplasmic reticulum membranes described as occurring in liver upon cessation of phenobarbital exposure. It is concluded that phenobarbital treatment per se decreases lysosomal enzyme activities, whereas the induced autophagy following cessation of exposure is associated with enhanced levels of lysosomal hydrolases in rat liver.