Influence of calcium and magnesium containing fixatives of the ultrastructure of parathyroids

Wild, P.; Bertoni, Guiseppe; Schraner, Elisabeth M.; Beglinger, R

doi:10.1016/0739-6260(87)90025-6

Cited by 14 publications

(8 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Loss of both cytoplasmic and membrane material can be assumed to be enhanced in cells undergoing degenerative changes. They even may take place during postfixation with osmium tetroxide (Wild et al, 1987). Further, fixation is a rather slow process, considering both the penetration and reaction processes (Fox et al, 1985;Hayat, 1981).…”

Section: Discussionmentioning

confidence: 98%

Reevaluation of the effect of lysoyzme onEscherichia coli employing ultrarapid freezing followed by cryoelectronmicroscopy or freeze substitution

Wild

Gabrieli

Schraner

et al. 1997

Microsc. Res. Tech.

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 98%

Reevaluation of the effect of lysoyzme onEscherichia coli employing ultrarapid freezing followed by cryoelectronmicroscopy or freeze substitution

Wild

Gabrieli

Schraner

et al. 1997

Microsc. Res. Tech.

View full text Add to dashboard Cite

“…From each rat, small pieces (about 10 mm 3) of one lobe of thymic tissue were fixed by immersion in 0.1 M Na-cacodylate buffered 2.5% (v/v) glutaraldehyde and 2% (w/v) paraformaldehyde (pH 7.4) for at least 2 h at 4 ~ C. The buffer was supplemented with After washing, the tissue specimens were postfixed in 1% (w/v) osmium tetroxide in the same buffer supplemented with 500 p.M CaC12 and 1000 p.M MgC12, dehydrated and subsequently embedded in Epon 812. These ion supplements were employed to avoid ex vivo artefacts due to hypo-osmolality of the fixation buffers, which may result in an increased electron density of tissue elements (Wild et al 1987). Semithin sections (1 pm) were stained for light microscopy (Sato and Shamoto 1973).…”

Section: Methodsmentioning

confidence: 99%

Ultrastructure of the cortical epithelium of the rat thymus after in vivo exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Waal

Rademakers²,

Schuurman

et al. 1993

Arch Toxicol

View full text Add to dashboard Cite

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is known for inducing cortical atrophy in the rat thymus. The present study was conducted to provide ultrastructural evidence for the cortical epithelium to be a target for TCDD in vivo. Juvenile male Wistar rats were orally intubated once with either 50 or 150 micrograms/kg TCDD and killed 4 or 10 days thereafter. Major changes were found in the cortical thymic epithelium. First, a relative shift occurred from "pale" to darker cortical epithelial cell types, as judged by their nuclear and cytoplasmic electron density. This effect was most prominent at 10 days after exposure to 150 micrograms/kg TCDD. The increased electron density of the cortical epithelium indicates an altered state of cellular differentiation. Secondly, at the 150 micrograms/kg dose level focal epithelial cell aggregates were seen both at day 4 and day 10 after administration. This aggregation may either be compound induced or represent a secondary event to the collapse of the thymic stroma. Thirdly, increased vacuolation of cortical epithelial cells was apparent. This effect is interpreted as a consequence rather than a cause of thymocyte depletion from the cortex. This study indicates that TCDD exposure affects the cortical epithelium of the rat thymus at a high dose level. Electron microscopy reveals that the differentiation of epithelial cells is altered. In addition, epithelial cell aggregates are formed.

show abstract

“…1). This appearance, however, can be effectively affected simply by adding Ca and/or Mg ions in the micromolar range to Na-cacodylate for buffering both glutaraldehyde and OsO, (Wild et al, 1987a). For example, addition of 500 pM CaC1, to 0.1 M Na-cacodylate as buffer for 2.5% GA and 1% OsO, or the addition of 250 pM or 500 pM CaC1, or MgC1, to 0.1 M Na-cacodylate as buffer for OsO, resulted in the formation of dark and light cell variants in parathyroids of cats.…”

Section: Appearance Of Principal Parathyroid Cells Inmentioning

confidence: 99%

Mammalian parathyroids: Morphological and functional implications

Wild

Setoguti

1995

Microscopy Res & Technique

Self Cite

View full text Add to dashboard Cite

Fixation with aldehydes is achieved either by immersion or perfusion. The parenchyma of parathyroid glands fixed by immersion consists of dark cells containing a lot of membranes of these organelles which are concerned with hormone secretion, light cells which are poor in these organelles, intermediate forms between the two, and multinuclear syncytial cells. They have been attributed to represent different functional stages of secretory activity, the dark cell being in an active form, the light cell in a resting form. Studies of the parathyroids of mice, rats, rabbits, cats, dogs, pigs, cattle, sheep, goats, and horses employing various fixation protocols clearly demonstrate that light cell variants and multinuclear syncytial cells are formed during improper immersion fixation as a result of membrane disintegration. Parathyroids fixed by perfusion or by immersion in an appropriate fixation medium comprise only one cell type which correspond to the dark chief cell. Parathyroid cells are polar cells bearing some of the rough endoplasmic reticulum in the basal pole, the rest of it, the Golgi complex, and secretory granules in the apical pole. The secretory product is released by exocytosis at the apicolateral domain of the plasma membrane into the intercellular space. Secretory activity can be altered experimentally, leading to drastic changes in the amount of cell membrane related to hormone synthesis, intracellular transport, exocytic release, and secretion coupled membrane retrieval. The sensitive reaction of parathyroid cells to both the mode of fixation and to fixation media demands careful evaluation of the fixation protocol. This and the polarity of parathyroid cells have to be borne in mind for estimating secretory activity on the basis of morphological criteria.

show abstract

Influence of calcium and magnesium containing fixatives of the ultrastructure of parathyroids

Cited by 14 publications

References 34 publications

Reevaluation of the effect of lysoyzme onEscherichia coli employing ultrarapid freezing followed by cryoelectronmicroscopy or freeze substitution

Reevaluation of the effect of lysoyzme onEscherichia coli employing ultrarapid freezing followed by cryoelectronmicroscopy or freeze substitution

Ultrastructure of the cortical epithelium of the rat thymus after in vivo exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)

Mammalian parathyroids: Morphological and functional implications

Contact Info

Product

Resources

About