Proportion Of Giant Cells Research Articles

Growth characteristics of diabetic rat ectoplacental cones in vivo and in vitro.

To investigate the outgrowth of the ectoplacental cone in diabetic rats in vivo and in vitro. Female Wistar rats were injected intraperitoneally with streptozotocin (75 mg/kg body weight, n = 15), or with control buffer (n = 27) 3 days before mating. On day 9 (day 1 = copulation plug) decidual swellings were weighed and the volume and mitotic index of the embryo and ectoplacental cone were estimated. Also, ectoplacental cones were cultured either in the presence of decidual cells from pseudopregnant diabetic rats or in high glucose concentration media. Cultures were evaluated by the daily outgrowth and by the proportion of giant cells and proliferating cells on day 5. In diabetic rats on day 9, the weight of the decidual swellings and the mitotic index in the ectoplacental cone were lower compared with controls (p < 0.0001 and p < 0.05, respectively). In vitro, control ectoplacental cones in the presence of decidual cells from diabetic rats showed a slight reduction in outgrowth on day 3 and 5 of culture. Outgrowth of diabetic ectoplacental cones in high glucose concentration medium was impaired on day 1 (p < 0.0005) compared with control ectoplacental cones in control medium, and on day 1 and 2 (both p < 0.005) compared with control ectoplacental cones in high glucose concentration medium. In control medium, the outgrowth of diabetic ectoplacental cones was impaired on day 1 (p < 0.05), compared with control ectoplacental cones. Proliferation was stimulated in diabetic ectoplacental cone cultures. These data suggest that the outgrowth of diabetic ectoplacental cones is impaired by high glucose concentrations.

Clonal heterogeneity in the progeny of HeLa cells which survive X-irradiation.

Clones of HeLa cells that had survived 9 Gy X-rays were investigated for plating efficiency, radiosensitivity, the proportion of giant cells, and chromosome numbers. A significant decrease in plating efficiency was observed that persisted for > 20 population doublings. The reduced plating efficiency was associated with an increased proportion of giant cells in the colonies. There was pronounced clonal heterogeneity in the progeny of irradiated surviving cells with respect to plating efficiency, proportion of giant cells, and chromosome numbers. The radiosensitivity of progeny from irradiated cells did not change compared with controls.

Effect of some endodontic materials on the influx of macrophages and multinucleated giant cell development in experimental granulomas

Calcium hydroxide, AH-26, and zinc oxide-eugenol greatly influenced the influx rate of mononuclear phagocytes and the fusion potential of these cells in coverslip granulomas. Zinc oxide-eugenol reduced the fusion index and the proportion of multinucleated giant cells in the short- and long-term implant periods. This along with the greater rate influx of mononuclear macrophages suggests that this material was highly cytotoxic for macrophages. Calcium hydroxide did not greatly influence the fusion process and the rate of entry of mononuclear phagocytes. This indicates that calcium hydroxide developed a low toxic effect on macrophages. AH-26 increased the influx rate of mononuclear phagocytes during the 4-, 8-, and 12-day implant periods. In the 24-, 30-, and 40-day periods the proportion of mononuclear macrophages decreased, and in the 30- and 40-day periods the values remained between the above mentioned materials. Fusion index and the proportion of giant cells was also depressed during the long-term implant period, suggesting that AH-26 should be considered mild to moderate in toxicity to the macrophage system.

Regional specialization in the golden hamster's retina.

Ganglion cell swere counted and measured in whole mounts of the hamster's retina, stained with methylene blue. Their density varies between about 1,000/mm2 at the edge of the retina to about 5-6,000/mm2 in a broad area centralis centred about 1.9 mm(39 deg) directly temporal to the optic disk. Maps of cell density show a long horizontal extension of the dense area in the nasal direction. The sizes of ganglion cell somata fall into two main groups--small cells (5-11 mum diameter) and large cells (greater than 11 mum), the latter including a small proportion of giant cells (greater than 17 mum). All three classes of cells are maximal in density in the area centralis, although the small cells are relatively more numerous there. The total number of cells is about 114,000 with about 63,000 small cells and about 51,000 large. The optic nerve contains about 69,000 unmyelinated axons and about 50,000 myelinated axons, suggesting that the latter are the fibres of the larger ganglion cells. It is likely that the projections of the centres of the areae centrales of the two eyes are normally divergent in space; they are therefore not on "corresponding retinal points."