Wall Of Animals Research Articles

Gut-associated lymphoid tissue in the large intestine of calves. I. Distribution and histology.

Gut-associated lymphoid tissue (GALT) in the large intestine was characterized in 12 calves (10 to 84 days old) obtained at necropsy (7, group A) or healthy animals (5, group B). Patches of mucosal lymphoid follicles were in all calves at ileocecal entrances (ICE), 23-42 cm distal to the ICE in the proximal loop of the ascending colon (proximal colon [PC] patch), and in the terminal rectum. PC patches varied from 8 to 30 cm in length. Solitary lymphoid follicles were found in the cecum of three calves, between the ileocecal entrances and the PC patch in four calves, adjacent to the PC patch in all calves, and in the ampulla recti. GALT occupied 7.8% of the large intestinal wall in animals of group A: 0.6% at the ileocecal entrance, 4.8% in the proximal colon, and 2.4% in the rectum. There were two different types of mucosal lymphoid follicles in group B: propria nodules with lymphoid follicles predominantly in the lamina propria, and lymphoglandular complexes with lymphoid follicles in the submucosa. In three 3-, 6-, and 7-day-old, germfree calves, distinct follicle-associated epithelium covered propria nodules and covering folds in depths of the lymphoglandular complexes; it was characterized by numerous intraepithelial cells and lack of goblet cells.

The role of circulating antigen in the formation of immune deposits in experimental membranous nephropathy.

To investigate the role of circulating antigen in the formation of subepithelial immune deposits in the Heymann rat model of membranous nephropathy, the renal uptake and site of renal deposition of intravenously injected renal tubular antigen (F X 1A) was studied. F X 1A, (15, 30, 60, and 600 micrograms) radiolabeled with 125I, and bovine serum albumin (BSA; 15 micrograms) labeled with 131I were intravenously injected into naive rats. Plasma clearance and organ uptake of brush border antigens were determined. Of the injected F X 1A, 75% was cleared from the circulation by 1 hr as compared to 10% of the BSA. Uptake of F X 1A by heart, lung, and spleen was less than 1% at all doses studied. Renal uptake of F X 1A (29.8 micrograms/g tissue) was greater than that for liver (4.75 micrograms/g), spleen, heart, and lung (each less than 1 microgram/g tissue). Evaluation of washed renal homogenate and isolated glomeruli confirmed specific tissue-associated F X 1A antigen. Direct immunofluorescence demonstrated deposits of F X 1A antigen along the glomerular capillary wall in animals injected with F X 1A. Small scattered electron dense deposits were demonstrated in the subepithelial space. Similar binding could be reproduced in vitro by incubating cryostat sections of normal rat kidney or isolated glomeruli with solubilized F X 1A antigens. Direct binding of a tubular antigen to a constituent of the glomerulus could initiate in situ immune complex formation, and may explain the variably demonstrable "cross-reactivity" of the Heymann antibody with the glomerular capillary wall.

Morphometric and dispersion analysis of lung acinus components during wholebody cooling

The high prevalence of diseases of the respiratory organs in persons resident in the Far North is known to be attributable to prolonged exposure to cold [I, 3]. However, the immediate mechanisms of cold injury to the lungs and its severity are not yet known. There have been isolated studies of the ultrastructure of the alveolar wall in animals [5, 7] exposed to below comfortable temperatures, and the ultrastructure of type II alveolocytes and surfactant during acute cooling, but no analogy can be drawn between these experiments and human residence in high latitudes.

Studies on the Acid Polysaccharides in Blood Vessel Walls (3) : INFLUENCE OF ACID POLYSACCHARIDES ON CAPILLARY FRAGILITY AND CAPILLARY PERMEABILITY IN EXPERIMENTAL HEMORRHAGIC DIATHESIS

The author studied the influence of hi acid and cho sulfate on capillary fragility and permeability of guinea pigs with experimental hemorrhagic diathesis (scurvy, thrombopenic purpura, vascular purpura). Capillary permeability is determined by the concentration of T-1824 in the plasma, and capillary fragility by the Borbely negative pressure method. Capillary permeability and fragility of normal male rats did not increase or decrease by administration of hi acid or cho sulfate. The increase of capillary permeability and fragility in experimental scorbutic guinea pigs was ameliorated by administration of Vitamin C or hi acid. hi acid seemed to inhibit the increase of capillary fragility and permeability in experimental thrombopenic purpuric guinea pigs. Increased capillary fragility of experimental vascular purpura was decreased by administration of hi acid. It seemed that cho sulfate did not ameliorate the increase of capillary permeability and fragility in the experimental hemorragic diathesis. Capillary fragility and permeability were not always parallel each others. In experimental vascular purpura, when the capillory fragility began to increase, the capillary permeability decreased. The contents of acid polysaccharides in blood vessel walls in animals with experimental hemorrhagic diathesis were approximately the same as in normal animals.