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Biomedical subjects

F Bianchi

Publications and source records attributed to F Bianchi.

At least 127 records · Page 7Linked to original sources
PubMed1989

Dimethylnitrosamine-induced cirrhosis. Evidence for an immunological mechanism.

The present study is concerned with the early events associated with the development of cirrhosis induced by dimethylnitrosamine (DMN). The antigenic expression of MHC class II components (Ia) and of some intermediate filament proteins (vimentin and desmin) have been studied by immunohistochemistry and the findings correlated with ultrastructural data. Micronodular cirrhosis developed after 3 weeks of treatment with DMN but enhanced expression of Ia antigen on macrophages and on infiltrating lymphocytes was observed after 1 week, before the formation of septa, suggesting that immune-mediated mechanisms are involved in the response to DMN-induced liver injury. The expression of vimentin and of desmin also increased at an early stage and at 3 weeks the septa were outlined by cellular elements showing positivity for both intermediate filament proteins. In keeping with these observations, ultrastructural data showed active division of macrophages in situ, infiltration of the parenchyma by T and B lymphocytes, activation of lipocytes (Ito cells) showing evidence of mitosis, and the presence of transitional elements between lipocytes, myofibroblasts and fibroblasts. This experimental model may be helpful in understanding the relationship between immune-mediated response to liver injury and development of hepatic fibrosis.

Animals↗
PubMed1989

Immune dysfunction in primary biliary cirrhosis. II. Increased production of prostaglandin E.

In a previous study we observed that after in vitro treatment with indomethacin, lymphocyte response to phytohaemagglutinin (PHA) in primary biliary cirrhosis (PBC) patients was higher than that of controls. We know that indomethacin also inhibits prostanoid production, and thus in the present work we directly measured prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) production by mononuclear cells and monocytes from 12 PBC patients, 11 control subjects, and three control disease patients (alcoholic cirrhosis, AC). PHA-stimulated enriched monocytes from PBC patients produced approximately threefold more PGE2 (after 48 h of culture) than did normal and AC monocytes (P less than 0.05). TXB2 production was similar in all groups studied. We also made cultures in which PBC-purified lymphocytes proliferated better than PBC mononuclear cells (i.e. lymphocytes plus monocytes). Thus, a monocyte population producing PGE2 could be responsible, at least in part, for the hyporesponsiveness to PHA observed in PBC patients.

Humans↗
PubMed1989

The significance of intestinal flow in the maturing of B lymphocytes and the chicken antibody response.

The aim of the present study was to evaluate the influence of intestinal material on the maturing of B lymphocytes in the bursa of Fabricius and on the antibody response to SRBC. Experiments were carried out on chicks whose burso-cloacal stalk had been ligated at hatching, in order to avoid any contact between the bursal tissues and intestinal material. Chicks subjected to a sham operation, or not operated at all, were used as controls. Results obtained by immunoperoxidase test, using an anti-chicken Ig antiserum, indicate that burso-cloacal stalk ligature leads to an increase in B cells in the bursa of Fabricius 20 days after the operation and a slight decrease after 60 days. The response to SRBC reveals an increase after 20 days, though no variations are found with respect to controls after 60 days. Thus, B lymphocytes mature independently of intestinal stimuli. Furthermore, observations carried out at the age of 20 days indicate that B lymphocytes disappear almost completely from the area of cloacal lymphoid infiltration in chicks with a ligated bursa. It is hypothesised that together with a systemic peripheralisation of B lymphocytes in secondary lymphoid organs and in blood, there exists an intramural local peripheralisation, which is interrupted by ligature of the burso-cloacal stalk.

Animals↗
PubMed1988

Distribution of esterase activity at the level of the epithelium of the diffusely infiltrated area (DIA) and of the cloaca in the Gallus domesticus: an ultrastructural study.

Esterase activity studies on the areas of lymphoid infiltration in the bursa of Fabricius (diffusely infiltrated area) and the dorsal wall of the cloaca showed that the epithelial cells exhibit varying degrees of diffuse esterase activity; it was possible to demonstrate the presence of spot-like esterase positivity in star-shaped cells in the epithelium itself. These cells can be found at various levels from the proximal to the distal region and have also been observed in the connective tissue of the tunica propria; as a result, the hypothesis has been advanced that they are connective tissue.

Animals↗
PubMed1988

Distribution of B-lymphocytes in the areas of bursal and cloacal lymphoid infiltration.

The present study was carried out on the Diffusely Infiltrated Area of the bursa of Fabricius (DIA) and the area of lymphoid infiltration of the dorsal wall of the cloaca, using immunoperoxidase and electron transmission microscopy, in order to verify the behaviour of antibody-producing cells and their distribution in the two organs. An anti-chicken Ig antiserum was used for this purpose, and the results obtained show that there is a progressive increase in the antibody-producing cells in the DIA, and subsequently also in the cloaca, during the first few weeks of life; the percentage values remain constantly higher in the DIA compared with the cloaca. Electron microscopy made it possible to detect numerous lymphocytes and some plasma cells in the epithelium. Many of the intra-epithelial lymphocytes were immunoperoxidase-positive. The possible role played by the B-lymphocytes found in both organs is discussed.

Animals↗
PubMed1988

Diffusely infiltrated lymphoid areas of the bursa of Fabricius (DIA) and of the cloaca: an embryological study with morphological analogies.

The aim of the present experiment was to verify whether the origin of the DIA is ectodermal or endodermal. A rabbit serum against the epithelial cells of the final portion of the cloaca was prepared. The indirect immunofluorescence method was applied to strips obtained with a cryostat, carefully cut in such a way as to include a part of the cloaca, the burso-cloacal stalk, the DIA, and the bursal plicae. In this way, it was possible to demonstrate that the epithelium of the cloaca, of the burso-cloacal stalk, and of the DIA exhibited an intense fluorescence that could not be observed at the level of the epithelium of the bursal plicae. These findings would appear to indicate that the DIA, like the cloaca and the burso-cloacal stalk, is ectodermal in origin. Furthermore, histological study revealed that the DIA exhibits close structural analogies with the dorsal wall of the cloaca. In both areas, unorganized lymphoid infiltrations of the tunica propria can be seen, and the epithelium does not show any follicle-associated epithelial cells. The glands often assume the aspect of dilated crypts containing intestinal transit material. The epithelium of these glands reveals lymphoid infiltrations at various points, and it is not uncommon to detect accumulations of cells in their lumina. Several groups of eosinophilic granulocytes can also be observed in the tunica propria of these two areas, with a clear predominance at the level of the DIA. These similarities between the cloaca and the DIA might lead one to suppose the existence of a functional as well as a morphological correspondence.

Age Factors↗
PubMed1987

Immune dysfunction in primary biliary cirrhosis (PBC): I. Increased sensitivity of PHA stimulated lymphocyte cultures to indomethacin.

A reduced responsiveness of peripheral blood lymphocytes from PBC patients to phytohaemagglutinin (PHA) was observed. Such an alteration may be related either to an intrinsic defect of T cells to proliferate or to a derangement of endogenously secreted mediators with regulatory functions, i.e., prostaglandins (PG). The role of the PG mediated suppressor system in 14 PBC patients and in 12 age and sex matched controls was evaluated. After the addition of indomethacin, the lymphocyte responsiveness to PHA increased in both controls and in PBC patients. However, this increment was statistically significantly only in PBC patients. The addition of PGE1 and PGE2 to PHA stimulated cultures decreased the lymphocyte proliferative activity. No differential sensitivity to PGEs was detectable in lymphocytes from PBC patients. Our data suggest, that, after polyclonal stimulation, mononuclear cells from PBC patient may release increased levels of PGEs which in turn affect the proliferative activity of mitogen activated lymphocytes.

Adult↗
PubMed1984

Ischemic necrosis of proximal gastric remnant following subtotal gastrectomy with splenectomy.

Ischemic necrosis of the gastric remnant is a rare and serious complication of high subtotal gastrectomy, rarely of the distal resection of the stomach. The authors report one case after subtotal gastrectomy with splenectomy, review the literature about this subject, and suggest that in all procedures the surgeon must take full account of the variability of gastric blood flow. Conservative therapy of this complication with total parenteral nutrition is proposed.

Adult↗