Your browser does not allow saving data (e.g. private mode): bookmarks will be lost when the tab closes.
Search PubMed
Keywords, author, journal, years — results from PubMed, abstracts with Russian translation, bookmarks in your browser.
Found: 5 468
Page 185 of 547-
Differentiation of human anterior hypophysial cells during fetal life.
This paper deals with cell differentiation in the anterior hypophysis of the human fetus, as may be stated by electronmicroscopy. In the 9 cm fetus the greater number of cells are devoid of granules; this was the reason for their being considered as nondifferentiated cells. A small number of cells however contain granules which vary from cell to cell in number and size and may be considered as cells with different functions. Usually the granules secreted within the same cell have very close diameters. The number of such cells increases with the age of the fetus; thus, in 170 mm fetal length there remain very few nondifferentiated cells. Some cells have their granules located centrally, while in others they are closer to the cell membrane, suggesting that the product of cell secretion is extruded in the nearby lumen of capillaries. The shape of the cells, their location, as well as the features of the cell organelles are similar to those described for adults, but in the fetus they are proportionally fewer. The electronmicroscopic pattern does not seem to be a sufficient criterion for the specification of the type of cells, except ACTH-MSH secreting cells.
-
Electron microscopic observation on rat ovaries in different stages of development and steroidogenesis.
-
The fine structure of some intraganglionic alterations. Neurofibrillary tangles, granulovacuolar bodies and "rod-like" structures as seen in Guam amyotrophic lateral sclerosis and parkinsonism-dementia complex.
-
[On the fine structure of the subformical organ of the cat. 3. Nerve and glial cells].
-
Some light- and electron-microscopical observations on the pars tuberalis of the pituitary gland of the rabbit.
-
Intercisternal parallel filaments in the endoplasmic reticulum in cells of the rat subcommissural organ.
-
[Peculiar neuronal cells in the ependyma of the central canal of Salamandra maculosa].
-
An electron microscopic study of the neuroglia during postnatal development of the rat cerebrum.
-
Amino acid neurotoxicity: intracellular sites of calcium accumulation associated with the onset of irreversible damage to rat cerebellar neurones in vitro.
Electron microscopy and the combined oxalate-pyroantimonate technique were used to locate calcium in intracerebellar nucleus neurones of rat cerebellar slices subjected to a neurotoxic concentration of N-methyl-D-aspartate. After a sub-lethal exposure period (5 min) calcium pyroantimonate deposits were found in swollen cisterns of the Golgi apparatus and, in lesser amounts, in the nuclei. Deposits were more prominent in the nuclei after a just-lethal exposure (10 min) when they were additionally observed within a population of swollen mitochondria and also apparently free in the dendritic and somatic cytoplasm. The results support the proposal that amino acid neurotoxicity is a consequence of an intracellular Ca2+ overload brought about by excessive Ca2+ influx.
-
The influence of noradrenaline on the process of protein/peptide secretion in the mammalian pineal organ. Comparative in vitro studies.
From studies conducted with the pineal organ of the mouse, it was ascertained that for the in vitro investigation of secretory processes (synthesis and release) of proteic/peptidic compound(s), a culture time of 5 to 14 days is optimal. A 5-day organ culture was therefore chosen to study the effects of noradrenaline on these secretory processes. Addition to noradrenaline to the culture medium provokes, in pineal explants of the normal mouse and the "eyeless" mouse, an inhibition of the secretory process, characterized by the formation of granular vesicles. In the hamster and rat, however, opposite results were obtained. Moreover, it appears that noradrenaline, at least in the rat, may also be involved in the regulation of the ependymal-like secretory process. The present results indicate clearly that noradrenaline (thus, the sympathetic innervation) is implicated in the regulation of the production of proteic/peptidic hormonal agents, but that the effect of this neurotransmitter is species-specific. This could explain the numerous contradictory results reported in the literature.