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P Skaaring

Publications and source records attributed to P Skaaring.

8 recordsLinked to original sources
PubMed1978

Tumor cell interactions in vitro microtubules, 100 angstrom filaments, and contractile microfilaments of tumor cells involved in "emperipolesis".

An increase in the number of examples of emperiopolesis, i.e., cells within cells, was observed subsequently to addition of Bt2cAMP to spinner flask cultures of JB-1-E tumor cells. A conspicuous arrangement of microtubules and 100 angstrom filaments in the tumor cells involved in emperiopelesis was observed. Absence of emperipolesis in cultures treated with cytochalasin B indecates a possible role of the contractile microfilaments in the events leading to emperiopolesis. The significance of and the term emperipolesis are discussed.

Animals↗
PubMed1978

Tumour cell interactions in vitro. Evidence for the occurrence of tumour cells within other tumour cells.

After addition of dibutyryl cAMP to spinner flask cultures of JB-1-E tumour cells an increase in the number of examples of emperipolesis was observed. Ruthenium red staining of the cells revealed a conspicuous staining of the cell membrane of the outer cell, while that of the inner cell was unstained. The differences in staining properties of the cell membranes of the outer and inner cells involved in emperipolesis and apparently viable inner cells make it evident that coexistence of cells--one within another--is possible.

Animals↗
PubMed1977

Further evidence for the existence of intralobular nerves in the rat liver.

In a recent study (Skaaring and Bierring, 1976) we found cholinesterase-positive nerve-like structures in the lobules of rat liver, and scanning electron microscopy revealed cords having a distribution pattern similar to that of the cholinesterase-positive structures. To obtain further evidence for an intralobular nerve supply the methods of cobalt and Procion Yellow nerve staining (Stretton and Kravitz, 1968; Iles and Mulloney, 1971; Pitman, Tweedle and Cohen, 1972) were adapted, iontophoretic introduction of the dyes being attempted through cut axonal ends in the surface of small excised blocks of rat liver.

Animals↗
PubMed1977

Surface structure of tooth germs from newborn infants: a light and scanning electron microscopical study.

Tooth germs from the mandibles of 5 stillborn infants were examined by scanning electron microscopy and light microscopy in order to investigate the surgace structure at different stages of mineralization. The surface of the completed enamel of the incisal third of the incisors was smooth, indicating that amelogenesis was at an end. The interface relief between ameloblasts and enamel matrix on the remaining part of the incisors, and on the forming cusps, was characterized by numerous deep pits caused by the Tomes' processes of the ameloblasts. When parts of the organic matrix were removed by sodium hypochlorite, the crystals were exposed as needle-shaped structures. Towards the bases of the cusps the pits gragually smoothed out, continuing as a narrow even surface zone corresponding to the first formed aprismatic enamel. In this zone circular holes 1 micronm were encountered which the light microscope studies showed were dentinal tubules passing into the enamel. At the bases of the cusps there was a rather abrupt demarcation toward a surface zone exhibiting countless slender villi. The light microscope observations indicated that these villi represented the first formed dentine after the basement membrane had disappeared.

Amelogenesis↗
PubMed1976

On the intrinsic innervation of normal rat liver. Histochemical and scanning electron microscopical studies.

With the Bodian method stained fibers were observed in the lobules of the rat liver and with the modified Karnovsky and Roots thiocholine method cholinesterase (presumably acetylcholinesterase (AChE))-positive nerve fibers were found in a pattern similar to that of the Bodian-stained fibers. The AChE-positive nerve fibers form a network in the liver lobules in close relation to hepatocytes and sinusoids. Fluorescent varicose nerve fibers demonstrated by the glyoxylic acid and Falck-Hillarp fluorescence methods were found only in the interlobular spaces associated with vessels. As no overlapping of distribution patterns of AChE-positive nerve fibers and fluorescent nerve fibers occurs, the AChE activity of the nerves of the liver lobules probably reflects the associated presence of acetylcholine in the nerve fibers. In consequence we suggest that nerves of the liver lobules belong to the autonomic parasympathetic nervous system. SEM of liver tissue revealed light cords apparently situated in smooth-surfaced channels between adjacent hepatocytes and in the space of Disse, where fibers also cross sinusoids. We tentatively suggest that the cords of the SEM represent the AChE-positive nerve fibers of our LM observations.

Acetylcholinesterase↗
PubMed1975

Increasing occurence of tumour cell -- tumour cell emperipolesis in the regenerating JB-1 ascites tumour.

During the investigation of JB-1 ascites tumour cells in recurrent growth several cases of emperiopolesis were observed. Different types of emperipolesis are presented. Light microscopical serial sections, autoradiography and transmission electron microscopy indicate that the cells involved in emperipolesis are separate cells, and the authors suggest that cytopagocytosis is the initial mechanism in the development of emperipolesis.

Animals↗