ABSTRACT
The supernatant fluid of axenically grown Entamoeba histolytica-HM1 significantly modifies the ultrastructural features associated with monocyte chemotaxis as assayed in Boyden chambers. This morphological evidence supports the existence of a factor, monocyte locomotion inhibitory factor (MLIF), produced by E. histolytica that inhibits the in vitro locomotion of human monocytes. None of the leucocyte-locomotion modifying drugs included in this study (i.e., cytochalasin-B, colchicine, vinblastine, and hydrocortisone) caused changes totally comparable with those induced by MLIF. The most striking feature was the increase of centriole-associated microtubules induced by MLIF and by cytochalasin-B. MLIF may inhibit monocyte locomotion by directly inducing excessive microtubule assembly, although a direct, if somewhat weak effect upon microfilaments cannot be excluded. The increase in microtubules could then represent a perhaps futile attempt of the microtubule organizing center to overcome the locomotion blockade that has occurred elsewhere in the cell. If active in vivo, MLIF may contribute to the paucity of inflammation in the advanced stages of invasive amebiasis, and consequently to the lack of scar tissue formation upon recovery from such lesions, as monocytes constitute an essential link to the healing process.
Subject(s)
Chemotaxis, Leukocyte/drug effects , Entamoeba histolytica/metabolism , Monocytes/ultrastructure , Colchicine/pharmacology , Cytochalasin B/pharmacology , Humans , Hydrocortisone/pharmacology , Monocytes/drug effects , Vinblastine/pharmacologyABSTRACT
Antitrypsin activity was studied in 62 sera of patients with cancer and in healthy volunteers. In 68% of the former there was diminished the activity of the trypsin inhibitor. Arbitarily 100 was established as the mean value for normal sera; the mean value found for cancer population was 83.62+/-27.05 (P less than 0.05).
