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Biomedical subjects

J Kärner

Publications and source records attributed to J Kärner.

4 recordsLinked to original sources

Ultrastructural morphometry on human parathyroid tissue. Morphological and functional implications.

Ultrastructural morphometry was performed on human parathyroid tissue from adenomas in chronic and acute (pernicious) hyperparathyroidism (HPT) including contralateral atrophic glands with the aim to compare the observed alterations with the corresponding clinico-functional findings. Quantitative assessment of various cell organelles, nucleus and cell perimeter revealed that significant correlations between ultrastructural features and laboratory parameters were only calculable by regarding extreme ranges of functional stages, i.e. adenomas of acute HPT (hyperparathyroid crisis) and contralateral atrophic glands. In chief cells of chronic HPT there was an inhomogeneity of measurements due to the disparate composition of the adenomatous tissue. Our results show that large complex lipid bodies and extensive accumulations of glycogen are valuable indicators of a functionally suppressed chief cell in atrophic parathyroid glands. An increased number of coated pits and vesicles is amongst other features (increase in size or number of Golgi apparatus, rough endoplasmic reticulum, mitochondria, nucleus and nucleolus as well as extension of the plasma membrane) characteristic of an endocrine stimulation.

Acute Disease

Virus-like particles in yeast: isolation and infectivity.

Virus-like particles containing electron dense cores are seen in thin sections of intact and degenerated cells of a thermosensitive (ts) strain of Candida tropicalis. A particulate fraction not present in wild-type cells has been isolated from the ts cells disrupted by pressure. The particles are 80-120 nm in diameter. Empty particles with a central cavity are observed. The method of infecting mating pairs of Saccharomyces cerevisiae by partially purified particles is described.

Candida

Distribution of acid phosphatase in chick Hensen's node.

Acid phosphatase distribution and yolk drop ultrastructure in Hensen's node of chick blastoderm at Hamburger-Hamilton stages 3 and 4 are described. At stage 3 large deposits of the reaction product are localised in type-A yolk drops, where signs of intensive degradation are seen. It seems that during this degradation lipid droplets are being formed in the degrading yolk drops. Partly digested yolk drops with a vesicular appearance are extruded from the cells, especially in deeper layers of the node. The phosphatase reaction product is also distributed into intercellular spaces. At stage 4 the cells of the node are more vacuolated and contain acid phosphatase and electron-dense yolk drops in lesser amounts. The possible physiological role of acid phosphatase in Hensen's node during gastrulation is discussed.

Acid Phosphatase

Macrobodies in chick blastoderm.

The results of this study show that the epiblast cells of chick blastoderm at Hamburger-Hamilton stage 1 contain macrobodies which themselves contain particles resembling the 'lining bodies' described by Bellairs. Since different structures ranging from macrobodies to light vacuoles have been found, it seems probable that their contents are utilized at this stage. Typically, they are surrounded by mitochondria, some of which have an abnormal internal structure. At later developmental stages neither macrobodies nor abnormal mitochondria were observed.

Animals