Biomedical subjects

H O Larsson

Publications and source records attributed to H O Larsson.

4 recordsLinked to original sources

PubMed1985

Quantitative morphological assessment of parathyroid activity in response to variations in calcium concentration in vitro.

Isolated parathyroid glands from gerbils incubated at low (0.5 mM), normal (1.25 mM) or high (3 mM) calcium concentration for 1 or 6 h were studied with regard to the following stereological parameters: the volume densities of the nucleus, mitochondria, endoplasmic reticulum, Golgi zone, lipid bodies, lysosomes, secretory granules and storage granules, and the surface densities of the cell membrane and endoplasmic reticulum. In glands incubated for 1 h no significant differences were seen between the experimental groups in any of the parameters investigated, however, the volume density of the Golgi zone and the surface density of the cell membrane were significantly increased in glands incubated for 6 h at low calcium concentration, compared with those incubated at high calcium concentration. The enlargement of the Golgi zone in stimulated glands was also evident when the two glands from the same animal incubated at different calcium concentrations were compared. The data suggest that the early response of parathyroid glands to altered concentration of extracellular calcium includes functional activities associated with the Golgi zone.

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PubMed1984

Structure of the parathyroid glands, as revealed by different methods of fixation. A quantitative light- and electron-microscopic study in untreated Mongolian gerbils.

Stereology and semi-automatic image analysis were used with the aim of comparing the structure of parathyroid glands from untreated adult Mongolian gerbils fixed by immersion with those fixed by perfusion. Subclassification of the chief cells based upon the staining affinity or electron density of the cytoplasm was readily performed only in glands fixed by immersion, and so-called atrophic cells were observed only in these glands. The atrophic cells were often surrounded by "light" chief cells. In glands fixed by perfusion, "light" chief cells were only rarely encountered. A significant difference between glands fixed by immersion and those fixed by perfusion was found only with regard to the form of cells and nuclei, those fixed by perfusion being more spherical. When comparing individual cells within glands fixed by immersion, "light" chief cells were more spherical and had a significantly larger nuclear and cellular size, and a lower mitochondrial volume density than the "intermediate"/"dark" chief cells. Otherwise there were no significant differences in any of the parameters investigated. These data indicate that occurrence of so-called "light" chief cells and atrophic cells is a result of improper fixation. The results of this study do not favour the concept of a functional cycle with a simultaneous occurrence of active and inactive cells within parathyroid glands.

Animals↗

PubMed1984

The normal parathyroid glands of the Mongolian gerbil. A quantitative structural study.

The parathyroid glands of the normal Mongolian gerbil were studied by light and electron microscopy, using stereology and semi-automatic image analysis. Basic quantitative data are presented for various nuclear parameters, and for mitochondria, endoplasmic reticulum, Golgi complex, secretory granules, storage granules, lysosomes and lipoid bodies. Chief cells predominate in the normal gland. Atrophic cells are only rarely encountered. The chief cells can be qualitatively subclassified into light, dark and intermediate variants, but quantitatively there is no difference among these variants with regard to the volume densities of mitochondria, lamellar rough endoplasmic reticulum, Golgi complex, secretory granules and storage granules, suggesting that the subclassification of the chief cells plays no functional role. A statistically significant correlation between volume densities of Golgi complex and secretory granules was found. Compared with the chief cells, the atrophic cells exhibit significantly less lamellar rough endoplasmic reticulum and secretory granules, whereas the content of vesicular rough endoplasmic reticulum is increased. The atrophic cells are suggested to be a degenerative variant of the chief cells.

Animals↗

PubMed1984

Quantitative parathyroid morphology is unaltered in prolonged hypocalcemia. A quantitative electron microscopic study in the Mongolian gerbil.

Hypocalcemia was induced in adult Mongolian gerbils by a combination of a calcium deficient diet and repeated injections of ethylene-diamine-tetra-acetate (EDTA). This treatment caused tetany and death in some of the animals. Laboratory analyses on the eight experimental day disclosed significantly decreased concentrations of serum calcium and significantly increased concentrations of serum phosphate. Stereological methods and semi-automatic image analysis were used for ultrastructural study of the parathyroid glands with the aim of disclosing if any quantitative alterations occur in prolonged hypocalcemia. Compared with normocalcemic animals no significant change was observed in the hypocalcemic gerbils with regard to the nuclear profile area, the volume densities of nucleus, mitochondria, endoplasmic reticulum, Golgi complex, lysosomes, secretory granules and storage granules, or the surface density of the cell membrane. The only significant change in the hypocalcemic animals was a slight increase in the volume density of lipoid bodies and a similarly slight decrease in the surface density of the endoplasmic reticulum, changes which at present are difficult to explain. The data demonstrate that hypocalcemic stimulation in vivo does not give rise to quantitative morphological changes in parathyroid chief cells, and thus do not support the idea of a functional adaptation of the chief cells to variations in the ambient calcium concentration.

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