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S Moskalewski

Publications and source records attributed to S Moskalewski.

At least 73 records · Page 4Linked to original sources
PubMed1980

Effects of colchicine on the Golgi complex and GERL of cultured rat peritoneal macrophages and epiphyseal chondrocytes.

Thioglycollate-elicited rat peritoneal macrophages and epiphyseal chondrocytes were cultured in vitro, treated with colchicine, and then studied by electron-microscopic and cytochemical techniques. Colchicine, but not lumicolchicine, caused disappearance of cytoplasmic microtubules and breakup of the Golgi complex with spreading of its dictyosomes from a well defined juxtanuclear area throughout the cytoplasm. There was also an altered distribution of lysosomes, which oriented themselves close to the dictyosomes both in control and colchicine-treated cells. Further, the structure of the individual dictyosomes was changed, especially in the chondrocytes. GERL equivalents were observed in control cells but were difficult to detect after exposure to colchicine. Reaction product for thiamine pyrophosphatase was found in narrow cisternae on the inner side of the dictyosomes in control cells but in vacuole-like structures in colchicine-treated cells. Reaction product for acid phosphatase was present in GERL equivalents and lysosomes in control cells but mainly in lysosomes in colchicine-treated cells. Nevertheless, the total specific activities of these enzymes as well as of 5'-nucleotidase, a plasma membrane marker, remained unaffected by the drug treatment. These observations show that cytoplasmic microtubules play an important and, in many respects similar, cytoskeletal role in two so functionally diverse cell types as macrophages and chondrocytes. They are particularly important for the structural integrity of the Golgi complex, which in both cells is normally organized in the area around the centrioles, from which numerous microtubules radiate into the cytoplasm. The observations further suggest that GERL is an integrated part of the Golgi complex in these cells.

Animals↗
PubMed1980

Influence of vincristine on the Golgi complex of leukaemic lymphoblasts.

In vitro and in vivo effects of vincristine on the Golgi complex of leukaemic lymphoblasts were studied. The cells incubated in vitro for 4 hours with vincristine of 1.25 x 10(-5) M concentration lacked microtubules, but regularly contained paracrystals and parallel arrays of macrotubules associated with ribosomes. The Golgi complex in control lymphoblasts was represented by 1-3 dictyosomes (stacks of cisternae) grouped in one area. After exposure to vincristine the dictyosomes lay at a considerable distance from each other. In many of them the cisternae were shorter than in controls and distended or transformed into large vacuoles. In cells incubated in vitro with lower concentrations of vincristine (1.25 x 10(-6) and 1.25 x 10(-7) M) and in cells obtained after the second therapeutic dose of vincristine (in the course of normal clinical treatment) neither changes in the Golgi complex nor formation of paracrystals and macrotubules were observed.

Adolescent↗
PubMed1979

Comparison of the in vitro effects of colchicine and its derivative colchiceine on chondrocyte morphology and function.

Colchiceine is a colchicine-metabolite which has been reported to inhibit axonal transport although not binding to brain tubulin. In the present study, colchiceine was shown not to depolymerize cytoplasmic microtubules, nor to mimic other effects of colchicine on the ultrastructure of cultured chondrocytes. In addition, the synthesis of proteoglycans was inhibited by colchicine but slightly stimulated by colchiceine. These results support the idea that the disturbances in cultured chondrocytes caused by colchicine are specifically related to a loss of cytoplasmic microtubules.

Animals↗
PubMed1979

Maturation of rabbit auricular chondrocytes grown in vitro in monolayer culture.

Chondrocytes isolated from auricular cartilage of 7-day-old rabbits were grown in vitro until the onset of phase III, occurring after 10-14 population doublings (PD). The size of cells and their dry mass were measured at various PD levels. These data were compared with results of analogous measurements of chondrocytes freshly isolated from 28-day-old rabbits. Both in vivo, during cartilage growth, and in vitro, some of the chondrocytes increased considerably in size and acquired two nuclei. Chondrocytes cultured in vitro for 4 population doublings were still capable of depositing elastic fibers in culture and forming cartilage after intramuscular transplantation. After longer periods of cultivation the ability of cells to produce a cartilage matrix declined. It is suggested that the auricular chondrocytes may represent a convenient model for comparative studies of cell aging in culture and in vivo, owing to the simplicity of matching senescent cells arising in both these situations.

Age Factors↗
PubMed1979

Bone formation in cartilage produced by transplanted epiphyseal chondrocytes.

Chondrocytes were isolated from rat epiphyseal cartilage, cultured in vitro, and exposed to exogenous tracers which accumulated in their lysosomes. The cells were then injected into the posterior tibial muscle of animals from the same outbred strain, where they reconstructed calcifying hyaline cartilage. The mineralization of the tissue was followed by ingrowth of blood capillaries from the host bed. Macrophage-like cells surrounding the vessels phagocytized degenerated chondrocytes and unmineralized matrix, whereas multinucleated chondroclasts removed some of the mineralized cartilage matrix. Mesenchyme-like cells accompanying the invading vessels attached to the remaining septa of calcified cartilage matrix and developed into osteoblasts depositing bone matrix on the surface of these septa. The apparent lack of inherent tracer labeling of the lysosomes in the different bone cells indicate that they were derived from the host. No signs of transformation of chondrocytes into bone cells were observed. When isolated rat epiphyseal chondrocytes were injected into the wall of the hamster cheek pouch, calcifying cartilage was reconstructed without signs of subsequent ossification. Transplantation of cartilage reconstructed in the hamster into the dorsal muscles of rats was, however, followed by formation of bone by a sequence analogous to that described above. Such an osteogenetic response was also obtained when the cartilage had been devitalized before transplantation. These experiments show that calcified cartilage, developing in or grafted into an intramuscular site, is able to induce and serve as a substrate for endochondral bone formation, similar to that occurring during normal development. They further indicate that bone induction by calcified cartilage does not require the presence of living chondrocytes.

Animals↗
PubMed1978

Effects of antimicrotubular agents on the fine structure of the Golgi complex in embryonic chick osteoblasts.

Embryonic chick frontal bones were cultured in the presence of colchicine or vinblastine and subsequently examined by tranmission electron microscopy. In control cultures the osteoblasts showed a large Golgi complex consisting of dictyosomes arranged in a well-defined juxtanuclear area. Microtubules were particularly numerous within this Golgi area although they could be observed throughout the cytoplasm. Colchicine and vinblastine caused the disappearance of cytoplasmic microtubules, while bundles of 10 nm diameter filaments appeared more frequently. In addition, cell polarity was lost and the Golgi complex became disorganized, with the dictyosomes randomly dispersed in the cytoplasm and showing a decreased number of cisternae and an increased number of vacuoles, the latter generally lacking stainable material. Increased number of autophagosomes were also noted. These findings indicate that microtubules function in the organization of the Golgi complex in osteoblasts. In view of the well documented role of this organelle system in collagen secretion it is suggested that previously observed secretory disturbances produced by antimicrotubular drugs may be due to a defective transfer of material to the dictyosomes and/or a defect in the packaging and transport of such material away from them.

Animals↗
PubMed1978

Proteoglycans synthesized by fetal guinea pig chondrocytes in culture.

Short term cultures were carried out with chondrocytes and tissue fragments from fetal guinea pig epiphyseal cartilage. Proteoglycans were isolated from these cultures and their properties were compared with those of proteoglycans from adult hyaline cartilage. It was concluded that the proteoglycans synthesized in culture were essentially similar to those present in cartilage matrix in vivo. The authors therefore suggest that fetal guinea pig chondrocytes cultured in monolayer or as aggregates in suspension constitute a useful system for the study of synthesis and secretion of proteoglycans.

Animals↗
PubMed1977

Fine structure of the golgi complex during mitosis of cartilaginous cells in vitro.

Chondrocytes were isolated enzymatically from guinea-pig epiphyses and grown in vitro. The fate of the Golgi complex during mitosis in relation to changes in the cytoplasmic microtubules was then studied by transmission electron microscopy. Interphase cells were observed to be polarized, with the Golgi complex occupying a well-defined juxtanuclear area of the cell's cytoplasmic pole. During prophase the cytoplasmic microtublues were largely lost, the nucleus moved to the center of the cell and the Golgi complex dissolved into single dictyosomes spread diffusely throughout the cytoplasm. The distribution of other organelles also changed to a more random pattern. In telophase, i.e. after the completion of nuclear division, the mitotic spindle decomposed and cytoplasmic microtubules reappeared. Furthermore, the organization of the Golgi complex and other organelles returned to that characteristic of interphase cells. Previous studies on cells treated with colchicine have indicated that the polarized distribution of cell organelles is dependent on the presence of intact cytoplasmic microtubules. It is suggested that the disappearance of such tubules observed here to be coupled with the disorganization of cell interphase structure fulfills the double function of providing free tubulin units from which to build the mitotic spindle and ensuring an approximately equal distribution of dictyosomes and other organelles to the daughter cells during cytokinesis.

Anaphase↗
PubMed1977

The influence of the degree of maturation of donor tissue on the reconstruction of elastic cartilage by isolated chondrocytes.

Chondrocytes isolated from auricular cartilage of 1-, 14-, 28- and 56-day-old rabbits were injected intrasmuscularly as auto- or allogeneic transplants, and the development of the reconstructed cartilage was compared to that of intact tissue. Chondrocytes in cartilage of 1- and 14-day-old rabbits (younger group) were relatively uniform in size. During further development in situ (28 and 56 days) central cells increased considerably and many of them became binucleated. Cartilage reconstructed by chondrocytes from the younger group of animals displayed regular arrangement of cells, i.e. smaller cells at the periphery and larger in the centre. Transplantation of chondrocytes from 28 or 56-day-old rabbits (older group) led to the reconstruction of cartilage with irregular distribution of cells, i.e. some large cells were located at its periphery, while in the centre smaller and larger cells were intermingled in a haphazard manner. Elastic fibres were scanty and thin in cartilage of 1-day-old animals, but their number and size increased with time and they displayed a characteristic pattern. Formation and maturation of these fibres proceeded in cartilage reconstructed by chondrocytes from the younger gorup of animals similarly as in the intact tissue. Chondrocytes from the older group of rabbits reconstructed cartilage in which the number of elastic fibres was reduced and their arrangement appeared irregular.

Age Factors↗
PubMed1977

Effects of colchicine and vinblastine on the phytohaemagglutinin-induced transformation of lymphocytes.

The effects of 2 microtubular-disruptive drugs, colchicine and vinblastine, on the phytohaemagglutinin (PHA)-induced blast transformation and mitogenic stimulation of human lymphocytes were studied. Both drugs markedly inhibited cell growth and DNA synthesis and lowered the mitotic index. No microtubules were seen with the electron microscope in cells treated with PHA plus colchicine or vinblastine. Moreover, the PHA-induced development of all organelles was partially inhibited by these drugs, especially that of the Golgi complex. As compared to cells treated with PHA alone, the dictyosomes were fewer, not so clearly localized in one area of the cytoplasm, and contained a decreased number of cisternae and an increased number of vacuoles. These results indicate that cytoplasmic microtubules play an important role in the PHA-induced blast transformation and mitogenic stimulation of lymphocytes. It is suggested that the microtubules function in the structural organization of the cell and particularly the Golgi complex. In the drug-induced absence of microtubules this and other organelle systems do not respond as usual to PHA stimulation, which could largely explain the decreased cell growth. This in turn suggests that lowered mitotic activity is a result of inhibition of cell growth, as a critical amount of G1-associated cell growth is believed to be required for the initiation of DNA synthesis and thus mitosis.

Colchicine↗
PubMed1977

Inflammatory giant cells: immunophagocytosis and rosette formation.

Mouse inflammatory giant cells formed after subcutaneous implantation of coverslips were exposed to sheep red blood cells opsonized with isologous antibodies. The maximal number of engulfed erythrocytes in numerous multinuclear cells exceeded that encountered in subcutaneous macrophages, but, on a per nucleus basis, the giant cells appeared less phagocytic.

Animals↗
PubMed1976

In vitro elastic fiber formation by aggregated arotic cells of newborn rabbits.

Cells isolated enzymatically from the aortas of newborn rabbits were aggregated and grown in organ culture. Bundles of microfibrils, some of them with an amouphous core (elastin), were evident in 3-day-old aggregates. Furthermore, droplets of elastin surrounded by darker dots and short filaments, corresponding to the elastic units were observed. In 6-day-old aggregates the number of elastic fibers composed of bundles of microfibrils with deposited elastin increased. Elastic elements which probably resulted from a coalescence of elastic units were also present. These two ways of elastic fiber formation in aggregates are compared with those described in papers on aortic development.

Animals↗
PubMed1976

Elastic fiber formation in monolayer and organ cultures of chondrocytes isolated from auricular cartilage.

Chondrocytes were isolated from auricular cartilage of immature rabbits and maintained in monolayer or organ culture for 14 days. In both types of culture the chondrocytes formed conspicuous elastic fibers. In monolayer culture the fibers could be identified by orcein staining in the culture dish. Electron microscopy of organ cultures revealed the presence of two basic components of elastic fibers, i.e. microfibrils and elastin.

Animals↗