In a recent paper, Sagiroglu & Sagiroglu (1970) reported findings which have a bearing on the mechanism of action of intrauterine devices (IUDs) in women. By preparing smears directly from Lippes loops ('coil smears') immediately after their removal from the uterus, they claim to have found `up to 50,000 macrophages on each slide', equivalent to `more than one million' per device in situ. They think that these cells have so far been overlooked by other workers and believe that they are capable of phagocytosing spermatozoa entering the uterus and, in the event of fertilization, the blastocyst.
Although the authors (Sagiroglu & Sagiroglu, 1970; Sagiroglu, 1971) show photomicrographs of the macrophages, they have so far given no detailed description of them. Similar cells, interpreted as macrophages, were also found by Joshi (1971)
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