Complement, polymorphonuclear leukocytes and platelets in acute experimental respiratory reactions to Aspergillus.
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Biomedical subjects
Publications and source records attributed to F H Green.
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The morphology of canine thoracic duct and peripheral collecting lymphatics was determined using light microscopy together with scanning and transmission electron microscopy (SEM and TEM). The thoracic duct was compared to the thoracic aorta and to the vena cava. Luminal surface detail was determined using the secondary imaging mode of the SEM. Subsurface nuclear and connective tissue detail was determined using back-scattered electron imagining combined with Willard's modification of Gomori's Methenamine Silver Stain. Central and peripheral lymphatic vessels have surface morphology distinct from either arteries or veins. The endothelial cell density in lymphatic vessels is less than in arteries or veins. The nuclear chromatin of lymphatic endothelial cells is coarsely granular and evenly distributed. This contrasts with nuclei from arteries or veins in which the chromatin is segmented. The distribution and orientation of lymphatic subsurface connective tissue fibers also differs from that seen in arteries and veins. It is concluded that canine lymphatic vessels have a unique surface and subsurface morphology and can be unequivocally identified by SEM.
In colonic adenocarcinomata abnormalities have been noted in all morphological aspects of the local immune system of the bowel; thus, in such tumours there is a defective production of secretory IgA, a diminished content of secretory component (SC) and a marked decrease in intraepithelial lymphocytes. By contrast, no such abnormalities were noted in the non-neoplastic areas of the bowel, either immediately adjacent to, or some distance from, the carcinoma. These findings suggest that there is not usually any generalised morphological abnormality of the local immune systems in intestinal neoplasia and that the immunological abnormalities noted within the tumour are a result of the changed nature of the epithelium, thus altering, or interfering with, the normal interactions between epithelial and lymphoid tissue in the gut.
A model of digestion is proposed in which oligopeptides arriving at the small bowel epithelium are bound to secretory antibodies, which hold them in contact with proteases and thus facilitate their breakdown and utilization. "Immunity" and "digestion" are thus seen as two sides of the same coin. Absence of this pathway, predictably, would cause a degree of malabsorption, while partial deficiency (either quantitative or qualitative) would give rise to a coeliac-like illness. Breast-feeding with colostrum and then milk provides the infant gut with both immunity and "digestivity", and this could be adopted therapeutically for coeliac disease and other consequences of local immunodeficiency.
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Twelve patients with ulcerative protocolitis were treated for six months with each of oral disodium cromoglycate (2 g/day) and placebo in a double-blind cross-over trial. The active drug significantly improved the patients' sense of well-being and the signoidoscopic and rectal biopsy appearances. Orally administered disodium cromoglycate may have a place in the long-term management of colitis.
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The numbers of mast cells and of IgE-containing immunocytes in the bowel wall of patients suffering from Crohn's disease of ulcerative colitis have been estimated and the results compared with those found in normal control specimens. In ulcerative colitis there is a slight rise in the number of mast cells and it appears that these participate in the inflammatory process in a non-specific manner; the number of IgE-containing immunocytes is not significantly altered. In Crohn's disease there is an almost total absence of stainable mast cells in affected areas of the bowel, together with a marked decrease in IgE-containing immunocytes. It is suggested that these findings are due to degranulation of mast cells and consumption of IgE as a result of an immediate hypersensitivity reaction in the bowel wall, this being one component of the protein inflammatory and immunological response to the entry of a variety of antigenic material.
Specimens of intestine from 24 patients with histologically proven Crohn's disease have been studies by an immunofluorescent technique for the distribution of immunoglobulins A, G, M, E, and D. A marked reduction of IgA in lymphoid and epithelial cells was noted in those areas of the bowel which, although histologically affected, were not ulcerated; in the histologically unaffected areas of the bowel the distribution of IgA was similar to that found in control sections of normal bowel. There was an increase in IG7 in the affected areas but the numbers of lymphoid cells staining for IgD did not differ from those found in normal controls; in 12 cases of Crohn's disease, however, IgG appeared to be present in bound form on the surface of, and in, the epithelial cells. It is postulated that the local deficiency in IgA in the affected areas may be secondary to a local cell-mediated immune reaction, to a focal metaplasia of the surface epithelium, or to patchy bindings of anticolon antibodies to the surface epithelium. The effect of this local deficiency of IgA will be to allow for an increased focal entry of antigenic material into the bowel wall, and it is suggested that many of the pathological features of Crohn's disease are explicable on the basis of deep penetration of a variety of antigens.
Immunocytes in the female genital tract are found principally in the endocervix. The predominant immunoglobulin produced in this site is IgA and this, together with the presence of secretory component in endocervical epithelium, indicates that a local secretory immune system, similar to that found in the gastrointestinal and respiratory tracts, exists in the endocervix. This local secretory immune system appears to be the major source of immunoglobulins in cervical mucus and the presence of secretory IgA in cervico-vaginal secretions provides an effective protection mechanism against viral and bacterial infections. Secretory IgA also acts non-specifically against exogenous antigens and may, by binding spermatozoal antigens, play a role in immunologically mediated infertility.
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