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Biomedical subjects

W G Spector

Publications and source records attributed to W G Spector.

11 recordsLinked to original sources
PubMed1979

Facsimile epithelioid cells obtained from stimulated peritoneal macrophages and their secretory activity in vitro.

Mouse peritoneal macrophages collected after exposure to new born calf serum in vivo were found to have some of the morphological and ultrastructural features attributed to epithelioid cells. These features were accentuated by short term culture in vivo or in vitro. Three accepted varieties of epithelioid cell were reproduced, i.e., those with predominant rough ER, those with predominant smooth vesicles and the plasmacytoid variety. Cells resembling fibroblasts were not seen, nor were lymphoid cells. The facsimile epithelioid cells had considerable secretory activity for a range of macrophage enzymes. They retained the phagocytic capacity and the surface receptors of macrophages but to a reduced extent. It is suggested that epithelioid cells are a form of stimulated macrophage, especially effective in enzyme secretion and liable to appear after excitation of the cell membrane by pinocytosis rather than phagocytosis.

Animals↗
PubMed1979

Inflammatory reactions in onchocerciasis: a report on current knowledge and recommendations for further study.

This report concerns the host's reactions to the presence of the parasite both in the course of the natural disease and during drug treatment. The various stages of Onchocerca volvulus are discussed in terms of the type of tissue reaction seen. The discussion then turns to basic hypotheses concerning the etiology of these reactions, emphasis being placed on the fact that while pathological changes are considerable in some locations there is a remarkable lack of reaction in others. Some of the mechanisms possibly involved in this apparent absence of host response are discussed, including anti-complement factors, poor antigenicity, acquisition of host antigen, immune tolerance, and blocking antibodies. In any study of the inflammatory response it is recommended that critical evaluations be made of histological material, haematological studies, the definition of the antigenic nature of O. volvulus, characterization of immunological reactivity of patients, and the definition of the migratory pathways of the parasite.The marked host reactions seen following chemotherapy, especially those related to the interaction of the drug diethylcarbamazine with microfilariae, are discussed at some length. The etiology of these reactions is considered and recommendations are made for the experimental elucidation of the mechanisms involved. Emphasis is placed on the necessity for detailed sequential histopathological and immunopathological studies in the definition of the tissue lesions found in onchocerciasis. Characterization of these lesions will assist greatly the approach to control of the adverse reactions seen during treatment.The use of anti-inflammatory agents in clinical trials is discussed and comments are made concerning the most suitable clinical situations for testing drugs and the types of drug that should be tested.

Anti-Inflammatory Agents↗
PubMed1977

Neoplastic macrophages grown from human leukaemic monocytes.

Leucocyte suspensions from some cases of acute myelogenous leukaemia produced large numbers of macrophages when cultured in vitro. The macrophages increased steadily in number during the first 1-2 wk of culture. The increase was partly derived from division of the macrophages themselves, partly from augmentation from supernatant cells not adherent to the surface of the culture flask. This augmentation occurred mostly in the first 24 hr of culture. The leukaemic macrophages had many features of normal macrophages as regards light microscopy, surface receptors, phagocytic activity and cytochemistry. Under the electron microscope, however, they had many abnormal characteristics, all of which have been recorded previously as features of malignant transformation. Cultures containing the abnormal macrophages and their precursor cells caused local solid tumours when injected into immune-deprived mice. The tumours were composed of rather uniform cells many of which resembled neoplastic reticulum cells. It is concluded that human leukaemic monocytes or promonocytes can develop into macrophages with ultrastructural features of malignancy. This appears to be the first demonstration of the development of neoplastic macrophages. It is suggested that some lymph node tumours of man may be composed of similar neoplastic macrophages and their precursor cells.

Animals↗
PubMed1976

Proliferation of macrophages in inflammation.

Proliferation of macrophages in chronic inflammatory loci is an essential part of granuloma development and as such helps to defend the host against dissemination of harmful microorganisms. Its induction seems to depend in part on local appearance of soluble mitogenic factors since sterile cell-free exudates will induce mitotic activity in vitro in a macrophage population otherwise unable to divide. Macrophage proliferation is probably checked and controlled by inherent restrictions on the number of divisions possible. This in turn probably depends on the rapid appearance of gross chromosomal defects, the effete cells being eliminated by their incorporation into multinucleate giant cells which then form non-viable polyploid cells.

Animals↗