Follicular dendritic cells in lymph nodes after x-irradiation.

in International Journal of Radiation Biology and Related Studies in Physics, Chemistry, and Medicine (1982), 42(2), 121-30

Follicular dendritic cells (FDC), non lymphoid cells present in lymph follicles, are characterized by numerous cytoplasmic processes retaining antigen-antibody complexes. Their origin, nature and function ... [more ▼]

Follicular dendritic cells (FDC), non lymphoid cells present in lymph follicles, are characterized by numerous cytoplasmic processes retaining antigen-antibody complexes. Their origin, nature and function are unknown. Mice inguinal lymph nodes after 4.5 or 7.5 Gy X-irradiation were depleted of lymphoid cells. Ultrastructural observations during the first few days post-irradiation show that FDC are unaltered and possess dendritic processes enveloping dense material. Furthermore, they show intense metabolic activity. A lamina densa, never observed so well-developed in other lymph node cells, was detected around the nuclear envelope. The localization of junctions between FDC was analysed. FDC preserve their typical cytoplasmic processes even if lymphoid cells are rare. The latter thus seem not to be responsible for the maintenance of FDC integrity or their development. The possible role of this for antibody production is discussed. Irradiated lymph nodes of lymphoid cells are highly convenient for studying FDC. Isolation of FDC from irradiated lymph organs would seem to be possible. [less ▲]

Relations entre immunogénicité et différenciation des métastases d'un mélanome expérimental chez la souris.

in Comptes Rendus des Séances de la Société de Biologie et de ses Filiales (1982), 176(2), 223-6

The graft into the footpad of Jackson mice of B16 melanoma cells which are only slightly pigmented, induces the simultaneous appearance of achromatic and well-pigmented metastatics. We have analysed ... [more ▼]

The graft into the footpad of Jackson mice of B16 melanoma cells which are only slightly pigmented, induces the simultaneous appearance of achromatic and well-pigmented metastatics. We have analysed histologically both types of metastases from the 8th to the 20th day after the resection of the primary tumor. The percentages of mitoses are higher in the achromatic metastases than in the pigmented ones. Both are infiltrated by lymphocytes and by a small number of macrophages and polymorphonuclears. A statistical analysis demonstrates however that the percentage of lymphocytes is not related to the importance of the metastase pigmentation. The discussion is devoted to the relations between the infiltration by lymphocytes, the immunogenicity and the differentiation of the tumor. [less ▲]

Histological structure and functions of synovium.

in Proceedings of the international symposium on articular synovium (1982)

Effets du cis-dichlorodiammineplatine (II) (cis-Pt II) sur l'ultrastructure de la chromatine de cellules animales ou vegetales et repercussions sur le cycle cellulaire.

in Comptes Rendus des Séances de la Société de Biologie et de ses Filiales (1982), 176(3), 364-8

Cultivated animal cells (mouse peritoneal macrophages, chick fibroblasts or mouse Ehrlich tumor cells) or Zea mays root tips are treated with cis-Pt (II). Various effects (chromatin dispersion or ... [more ▼]

Cultivated animal cells (mouse peritoneal macrophages, chick fibroblasts or mouse Ehrlich tumor cells) or Zea mays root tips are treated with cis-Pt (II). Various effects (chromatin dispersion or condensation, pycnosis) are observed under some experimental conditions in all cell types. Cytoplasmic ribosomes in helical aggregates appear but only in vegetal cells. Mitosis and cell cycle disturbances due to cis-Pt (II) are probably related to chromatin alterations. We suggest that the latter and helical polyribosomes are produced by cis-Pt (II) reaction with nucleic acids in these structures. [less ▲]

Etude ultrastructurale des effets de la neuraminidase sur des processus palatins de rat.

in Bulletin de l'Association des Anatomistes (1981), 65(190), 329-39

In a previous work, we demonstrated that palatine processes treated with 10 micrograms/ml neuraminidase for 30 minutes at 37 degrees C show a delayed fusion in vitro. In order to investigate the effects ... [more ▼]

In a previous work, we demonstrated that palatine processes treated with 10 micrograms/ml neuraminidase for 30 minutes at 37 degrees C show a delayed fusion in vitro. In order to investigate the effects of neuraminidase, the treated palatine processes were observed with the aid of transmission and scanning electron microscopy. The effect of neuraminidase is exclusively detectable on superficial flat cells of the palatine processes, especially the cells of the medial edge of the process. The epithelial basal cells remain unchanged. Observed with the S.E.M., the superficial epithelial cells show bubbles, become spherical and detached. To explain these observations, we namely propose the following hypothesis: the action of neuraminidase prevents the fusion of the palatine processes because it denudes basal cells bearing a too immature cell coat for ensuring sufficient adherence between the palatine processes. [less ▲]

Scanning electron microscopic study on the interaction of liposomes with cells in vitro

in European Journal of Cell Biology (1980), 22

Etude de la relation entre la structure chimique et l'activite antimitotique d'une serie nouvelle d'arylthioethers pyrimidiniques.

in Annales Pharmaceutiques Françaises (1980), 38(3), 267-70

Modifications des membranes foetales de la ratte apres amniocentese (observations preliminaires).

in Bulletin de l'Association des Anatomistes (1979), 63(180), 59-67

With the aid of scanning electron microscopy the normal pattern of both faces of amnion and visceral yolk sac were described. The inner face of the amnion turned towards the amniotic cavity is overlaid by ... [more ▼]

With the aid of scanning electron microscopy the normal pattern of both faces of amnion and visceral yolk sac were described. The inner face of the amnion turned towards the amniotic cavity is overlaid by large pavimentous cells bearing numerous microvilli. The opposite face, which delimits the exocoelome, consists of flattened fibroblasts separated by a fundamental connective substance. The two faces of the visceral yolk sac also show very different patterns. The exocoelomic face is covered by pavimentous cells ; these are smaller and bear less microvilli than amniotic cells. The yolk sac endoderm appears built up with prismatic or cubic cells, whose apical part is bulging and possesses a dense covering of microvilli. Amniocentesis effects are then reported. This intervention seems to provoke fetal membrane modifications only after 15 hours. These modifications essentially concern the visceral yolk sac whose exocoelomic cells are covered by more numerous microvilli which may show an intensification of a secretory process. [less ▲]

Effects of antimitotic agents either free or bound to DNA on mouse peritoneal macrophages cultivated in vitro.

in Virchows Archiv. B : Cell pathology (1978), 27(1), 79-87

Mouse peritoneal macrophages were cultivated in vitro and treated with ethidium bromide (EB) or with cis-dichloro-diammine platinum (II) (cis-Pt). EB provokes strong cytological alterations and cell ... [more ▼]

Mouse peritoneal macrophages were cultivated in vitro and treated with ethidium bromide (EB) or with cis-dichloro-diammine platinum (II) (cis-Pt). EB provokes strong cytological alterations and cell degeneration; cis-Pt was not toxic under our experimental contitions. EB-DNA complex penetrates into the macrophages, is liberated from DNA in vacuoles, then diffuses into the cell and is highly cytotoxic. Cis-Pt-DNA complex also penetrates into the cells, but cis-Pt cannot be released from DNA, cis-Pt-DNA complex accumulates inside cytoplasmic vacuoles but has no cytotoxic activity. [less ▲]

Etude des polysaccharides presents dans les cretes palatines du rat peu avant leur fusion.

in Bulletin de l'Association des Anatomistes (1978), 62(176), 65-76

When slices of rat palatal shelves removed by dissection from 16 days 8 hours old fetuses, just before fusion, are treated by the periodic acid Schiff reaction (PAS), colored substances may be detected ... [more ▼]

When slices of rat palatal shelves removed by dissection from 16 days 8 hours old fetuses, just before fusion, are treated by the periodic acid Schiff reaction (PAS), colored substances may be detected especially in the epithelium of the potential fusion zone; these substances are normally observed at the free surface of the epithelium. Our histochemical research, realized with the aid of the photonic microscope and of the transmission electron microscope, shows that most of the PAS positive material consists in glycogen; at the surface, this polysaccharide remains in the cytoplasm of flat degenerating cells and cannot be confused with the "cell coat" which presents no particularity, at this level, after demonstration by ruthenium red and by lanthanum nitrate. [less ▲]