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By
Ishikawa, Hidekazu; Maeda, Hidefumi; Takamatsu, Hisao; Saito, Yosio
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28 Citations
Summary
Systematic hyalinosis (juvenile hyaline fibromatosis) is characterized by hyalinized skin lesions. Electron microscopic examination of a hyalinized skin tumor from a 19-year-old man with this syndrome revealed that the hyaline was composed of ruthenium red-positive ultrastructures (granules, filaments, and a kind of cross-banded structure), indicating the presence of glycosaminoglycan or glycoprotein, and a small number of thin collagen fibrits. Using a new ruthenium red staining method combined with an enzymatic digestion procedure, it was demonstrated that the cross-banded structure and granules consisted of chondroitin sulfate-proteoglycan and/or glycoprotein, and that the cross-banded structure is probably a noncollageneous aggregate of the granules attached to the parallel-arranged filaments of hyaluronic acid-like nature.
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By
Genton, C. Y.
4 Citations
Summary
The fine structure of an ovarian clear cell carcinoma in a 65 year old woman was analysed. The tumor cells were of both clear and “hobnail” types. Both were characterized by the presence of short microvilli, abundant glycogen granules, a well-developed granular endoplasmic reticulum and Golgi apparatus, scanty lysosomes and very few lipid bodies. The tubules and gland-like spaces were always separated from the stroma by a basement membrane. At ultrastructural level the tumor cells do not resemble at all those of clear cell renal carcinomas. On the other hand, their submicroscopic features are strongly similar to those of the clear cell tumors found elsewhere in the female genital tract, emphasizing therewith their very probable müllerian origin. It is recommended to eliminate the term “mesonephroma ovarii” to designate the clear cell carcinomas of the ovary.
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By
Black, P. McL; Liszczak, Th.; Kornblith, P. L.
6 Citations
Summary
Cultured cells derived from a psammomatous meningioma were induced to from whorls in vitro by deprivation of nutrients. The ultrastructural features of desmosomes and junctional complexes were similar to sections from the surgical specimen; also prominent were 9–10 nm cytoplasmic filaments. Microelectrode recording of whorled cells showed a larger resting membrane potential than that of similar isolated meningioma cells in culture. Whorl formation seen in this tumor may be a result of relative nutritional deprivation and the need for metabolic cooperation among tumor cells.
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By
Domagala, Wenancjusz; Koss, Leopold G.
Summary
Surface configuration of mesothelial cells identified by light microscopy (LM) has been studied by scanning electron microscopy (SEM). It has been shown that mesothelial cells may have a variable SEM appearance. The surfaces of a small proportion of mesothelial cells are covered by regular microvilli (MV) and show openings of the pinocytotic vesicles. The surfaces of the majority of these cells are covered by vesicles or blebs. An intermediate population of mesothelial cells, i.e., cells displaying side-by-side blebs and MV, has also been observed. The latter cells no longer display pinocytotic vesicles. Occasional mesothelial cells have smooth surfaces. It has been shown by LM and transmission electron microscopy that cells with blebs are viable and capable of mitotic activity. It is concluded that mesothelial cells, detached from their epithelial setting, lose microvilli and pinocytotic vesicles and acquire surface blebs. The possible relationship between mesothelial cells and macrophages based on surface features has been discussed.
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By
Winston, M. L.
14 Citations
Summary
The timing of queen rearing and swarming are described after queens were removed from colonies of Africanized bees. New queens were reared from newly hatched to three day old worker larvae, many of which were moved in the egg or newly eclosed larval stages by workers into newly constructed queen cells. Mortality of worker eggs and larvae following dequeening was high, averaging 50%. When new queens emerged, swarms issued from two-thirds of the colonies. This process of queen replacement and queen-loss swarming differs from that of reproductive swarming in the lack of preparation before queen loss, longer queenless interval, lack of correlation between number of swarms and sealed brood area or number of queen cells, and lack of Congestion in colonies when swarms issued.
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By
Franck, Heinz-Gerhard; Knop, André
1 Citations
Zusammenfassung
Nachdenklich saß an einem Abend des Jahres 1781 der französische Papierfabrikant Joseph Montgolfier vor dem Feuer seines Kamins, als sich ihm plötzlich die Frage aufdrängte, ob es nicht möglich sei, das Gas, das den Rauch und die Funken emportrug, einzufangen, um es zum Heben von Lasten zu verwenden. Aus diesen Überlegungen vor dem Kamin entstand der “Aerostat” der Brüder Montgolfier, der am 7. Juli 1783 erstmals der begeisterten Öffentlichkeit vorgeführt wurde. Der Aerostat war ein Ballon, unter dem die Luft durch ein Feuer erhitzt wurde.
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