Archives d'anatomie microscopique et de morphologie experimentale最新文献

The authors studied, for the first time, the effects of 3-acetylpyridine administration on the nervous system of birds. The results were compared with those obtained in a mammal not studied yet. The data achieved from the guinea-pig confirmed substantially those got from other mammals, particularly from the rat. They pointed out the constant toxic action caused by the above drug inoculation on the central nervous system. The effects on birds are quite different: 3-AP administration, even at different doses from those employed in mammals, seldom provokes lesions of the central nervous system and the appearance of alterations does not depend on the considered species.

Quantitative changes in hepatocyte ultrastructures during normal gestation were studied in Wistar rats with morphometric methods. On the 18th day of the gestation, variations in nuclearcytoplasmic ratio, size of R.E.R., mitochondria, lysosomes and microbodies were observed, with variations according to the localisation of hepatocyte inside the lobule. We report the most obvious effects as follows: An increase of R.E.R. in the central and perilobular zones. Mitochondria are larger and the rounded forms are more numerous inside the two lobular zones. The number of lysosomes and microbodies are only elevated in the perilobular cells. In conclusion, it is suggested that the hepatocyte organelles are significantly increased during gestation. This is probably due to the metabolic activation. These cellular modifications are only one aspect of the liver increase.

The surface ultrastructure of ten human breast cancer cell lines were studied by utilizing the scanning electron microscope (SEM). Comparison revealed that all lines were richly covered with specific surface features and were pleomorphic with many spheroidal dividing cells. Microvilli (MV) were the main and almost constant surface feature. Blebs, microridges, cauliflower-like processes and/or various cytoplasmic cell processes were also seen. Specific reproducible surface characteristics could be seen in each cell line.

Sensitivity of cultured chick embryo heart cells to acetylcholine changes with time in culture. In 24 h cultures, about 25% of the cells exhibit a positive chronotropic response to acetylcholine. This effect is no longer observed after 48 h in culture. Positive and negative chronotropic effects of acetylcholine can be related to the presence of nicotinic and muscarinic receptors evidenced by autoradiography. Some data suggest a possible relationship between the type of sensitivity to acetylcholine and the changes in cell membrane properties occurring in culture.

The three concentric zones of the horse adrenal cortex (zonae glomerulosa, fasciculata and reticularis) showed marked interpenetration and exhibited a different relative development according to their position in the gland. Whereas the three cortical zones each had a specific histological structure, the ultrastructure of their cells showed a certain qualitative homogeneity. The differences corresponded essentially to the relative abundance of the constituents which are generally considered typical of steroidogeneous cells: mitochondria with vesicular cristae, smooth endoplasmic reticulum and lipid droplets. Their importance increased progressively from the zona glomerulosa to the zona reticularis. In this zone, the presence of gap and septate-like cell junctions, and mitochondria with vesicular cristae in close proximity to a smooth endoplasmic reticulum with numerous dilated tubules, suggested that steroidogenesis may be the most active. Ultrastructural findings were indicative of only quantitative differences between the steroidogenic capacities of the three zones of the mare adrenal cortex.