A POLICARD's research while affiliated with Institut National de la Transfusion Sanguine, Paris and other places

... Although the cytotoxicity of various modifications of silica and asbestos fibers has been studied extensively on phagocytic cells in vitro, the time of onset and the extent of damage are still under discussion. While some authors report extensive damage within minutes after the in vitro phagocytosis of certain mineral dusts (principally silica) (5)(6)(7)(8)(9)(10), others find that these cells are impaired only when incubated with the dust for long periods or with large amounts of it (11)(12)(13)(14)(15). ...

... Streaming of cytoplasmic granules has also been demonstrated by cinematography of mast cells obtained from peritoneal transudates evoked by particulate substances such as quartz (16). No ectoplasmic pseudopodial activity was reported, but the phase optics used in that study are not so suitable for this purpose as the Nomarski optics used in this study. ...

... A number of authors (King, 1966;Duncker, 1970;King & Molony, 1971;Bouverot, 1978;Meban, 1980) have remarked on the thinness of the avian blood-gas barrier. However, few actual measurements have been published, the only available data being approximate estimates by Schulz (1962), Policard, Collet & Martin (1962) and King & Molony (1971), and a preliminary report of the present work by Maina (1981). ...

... Since the structure of lung tissue in the normal rat has been described extensively in previous articles (40)(41)(42)(43), only a few points essential for the present study shall be highlighted. ...

... If high endothelial venules may become wider than medullary venules under certain conditions, this could favour the recruitment of blood lymphocytes by slowing flow in high endothelial venules. Irregularities of the endothelial surface of these venules, which are accentuated by vascular narrowing (Belisle & Sainte-Marie, 1985), may also facilitate recruitment (Policard, Collet & Martin, 1962; Cho & De Bruyn, 1986). The actual mechanism of recruitment still needs to be elucidated. ...

... This was confirmed in in vivo animal studies of rats where coal dust was supplemented with different concentrations of quartz. [8,[34][35][36] Three studies aimed at investigating the effect of the quartz on the occurrence of opacities and thereby indirectly stating the effect of the non-quartz part of the mixed coalmine dust. [16][17][18] In Hurley et al. [17], a large study with a high quality exposure assessment, they excluded an effect of ash. ...

... It has also been confirmed that quartz represents the most toxic form and that there is a relationship between increasing dust/silica concentration, number of bacilli and development of tuberculous lesions (62). Co-exposure in vivo in guinea pig models has also provided information about the active role of Mtb in pneumoconio-tuberculous lesion formation, with the introduction of the antituberculotic drug rifampicin resulting in decreased formation or its elimination (63). ...

... Second, the treatment of both types of aggregate with formic acid results in the complete removal of their granular and crystalline material, as discussed in detail below . Moreover, as far as the crystalline aggregates are concerned, their inorganic nature is proved by the fact that they are found in von Kossa-positive, alizarin red S-stained mitochondria and by the observation that they consist of structures which have the same morphology and give the same electron diffractograms as the inorganic crystals found in bone, cartilage, and dentine (8-10, 18, 19, 22, 23, 29, 30, 43, 46, 67, 117, 122, 132, 137) and in many calcified soft tissues (13,16,37,48,55,68,90,98,99,116) . ...

... Gangadharam and co-workers (108) administered silica intravenously to Swiss Webster mouse strain, infected them with M. intracellulare, and showed that they had a greater burden of bacilli in the lungs than control mice without silica exposure. Coal and quartz given to guinea pigs by inhalation increased the burden of M. kansasii lung disease even though the NTM was given intravenously (109). An often-cited mechanism for silicainduced susceptibility to mycobacterial infections is that following macrophage ingestion of silica particles, these phagocytes are impaired in their effector functions. ...

... Binding of uteroferrin by endothelial and(or) Kupfer cells appears to depend upon the mannose residues in the carbohydrate portion of the molecule (P.T.K. Saunders, unpublished data). Presumably, uteroferrin is directed to lysosomes where the iron is released to ferritin and transferred to erythroblasts by a process called ropheocytosis (Policard and Bessis, 1958) for synthesis of hemoglobin. ...