Biomedical subjects

E del Cacho

Publications and source records attributed to E del Cacho.

30 records · Page 2Linked to original sources

PubMed1996

Cytochemical study of the germinal membrane of the Echinococcus granulosus cyst.

The present cytochemical study was undertaken to provide more information on the localization of enzymatic and glycoconjugates in the germinal membrane of the Echinococcus granulosus cyst. The distinctive distribution of binding sites for two lectins (peanut agglutinin and Dilochos biflorus agglutinin) in the germinal membrane are described. An investigation is made of the distribution and specific activity of adenosine triphosphatase, alkaline phosphatase and acid phosphatase. The results suggest that cells located in the deeper layer of the germinal membrane are intrinsic in the cellular differentiation process. The dissimilarities detected in both the enzymatic activity and the lectin-binding receptors could be associated with metacestode development or degeneration.

Acid Phosphatase↗

PubMed1995

Localization of splenic cells with antigen-transporting capability in the chicken.

BACKGROUND: The objective of the present study is to investigate the migration pattern of the splenic dendritic cell of the chicken named the ellipsoid-associated cell (EAC) from the site of initial location at the periphery of the ellipsoid to the splenic T- and B-dependent areas. METHODS: Bovine serum albumin bound to biotin and conjugated to gold particles was used as a histochemically identifiable antigen detected as a peroxidase reaction. The antigen was intravenously injected, and subsequently its pattern of distribution in a time sequence and within the tissue was examined at the light and electron microscopy levels. In addition, an hour prior to sacrifice, the chickens received a single injection of the thymidine analogue 5-bromo-2'-deoxyuridine, in order to quantify the number of DNA synthesizing cells and to establish a relationship between the migrating EAC and the rate of mitosis in the white pulp. RESULTS: The observations showed that between 12 hours and 3 days after the second antigen administration the labeled EAC, which was first located around the ellipsoid, progressively reached further areas with time towards the periarteriolar lymphoid sheaths, where newly formed germinal centers appeared. Furthermore, the rate of cell proliferation within the white pulp was associated with the arrival of the antigen-transporting EAC. CONCLUSIONS: The results suggest that migrating EAC have a role as both antigen-transporting cell and antigen-presenting cell in the T- and B-dependent areas, as a result of which migrating EAC is transiently found in periellipsoidal white pulp, then periarteriolar lymphoid sheaths, and finally germinal centers, where it may function as an interdigitating cell or as a follicular dendritic cell, depending on its location. Thus, we conclude that the EACs are precursors of both interdigitating and follicular dendritic cells.

Animals↗

PubMed1995

Antigen-binding cells in the cecal tonsil and Peyer's patches of the chicken after bovine serum albumin administration.

It has been previously reported in the chicken that the ellipsoid-associated cells (EAC), which are considered to be a type of splenic dendritic cell, migrate from the spleen into the blood after binding antigen on their surface. In the current study we traced the localization of these cells within two peripheral lymphoid organs, the cecal tonsil (CT) and the Peyer's patches (PP). The migration of the cells was followed by light microscopy using bovine serum albumin bound to biotin and conjugated to gold particles as a histochemically identifiable antigen detected as peroxidase reaction. The observations showed that the EAC after entering the circulating blood migrated into the lymphoid tissue of the CT and the PP. As a consequence, the antigen-binding cells were found in the diffuse lymphoid tissue and the germinal centers in both lymphoid organs. In the former location they were seen 24 h after the second antigen administration and in the germinal centers on Day 3. In addition, antigen-binding cells started to be observed in the lymphoid tissue at the same time as T and B cells were found to proliferate by using 5-bromo-2'-deoxyuridine. Based upon these findings, we suggested that the EAC have a role as antigen-transporting cells from the spleen to the CT and the PP via the blood stream. Furthermore, our results provided evidence that after the antigen-transporting EAC entered the above-mentioned organs, these cells behaved as antigen-presenting cells in both the T- and B-dependent areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

Characterization of distal lymphoid nodules in the chicken caecum.

In this report, we describe lymphoid nodules consistently found in the distal region of each chicken caecum at approximately 3 cm from the ileo-cecal junction. These structures were studied by light microscopy both in normal and Eimeria tenella-infected chickens. They were observed with the naked eye in infected birds but not in normal chickens. In these latter the region of the caecal lamina propria corresponding to that in which the lymphoid aggregates were visible revealed a light infiltration by diffuse lymphoid tissue as well as a few germinal centers. The distal lymphoid nodules were studied using a panel of monoclonal antibodies which are specific for chicken Ig-containing cells, macrophages, Ia-like positive cells, and interdigitating cells, as well as a policlonal antiserum reactive with S-100 protein to stain both interdigitating cells and follicular dendritic cells. The immunohistochemical study demonstrated the resemblance of these aggregates to the caecal tonsils, suggesting that they represent specialized mucosa-associated lymphoid tissue that respond to antigens in the caecal lumen, their function being to enhance the mucosal defense provided by the caecal tonsils against antigens in the lumen of the caeca.

Animals↗

PubMed1993

Follicular dendritic cell activation in the harderian gland of the chicken.

The avian follicular dendritic cell changes that occur in the germinal center of the Harderian gland during the course of the immune response were studied by electron microscopy and the immunoperoxidase method was employed for the detection of S-100 protein. The chickens were injected twice with Salmonella O Antigen into the nictitating membrane at 9-day intervals. The follicular dendritic cells exhibited filiform processes at between 24 and 96 h after the second antigen administration. Filiform dendrites tended to convolute near the cell body. Therefore, it can be assumed that these processes make it more difficult for macrophages and B cells to make contact with the immune complexes retained by the follicular dendritic cells and, as a consequence, the period of antigen handling by these cells increases. Evidence is provided that the dendritic processes are closely associated with both lymphoblasts and lymphocytes. Furthermore, S-100 protein was found in the abovementioned cells exclusively and only in those cells where filiform dendrites were observed. These findings suggest that, during a secondary immune response, the follicular dendritic cell undergoes a functional activation which involves morphological changes and the phenotypic expression of the S-100 protein. This activation is hypothesized to be similar to that described for follicular dendritic cells in mammals after fixing immune complex.

Animals↗

PubMed1993

Immune complex-mediated glomerulopathy in Barbus graellsi infected with Myxobolus spp.

Membranous glomerulonephritis caused in Barbus graellsi by myxosporidian infections have been studied by electron microscopy and immunoelectron microscopy techniques. This study indicates that Myxosporidian infection produces a chronic severe aggression. Spores reach the spleen, the kidney and the liver, where they are trapped and phagocyted by Melano Macrophage Centres. Consequently, the commencement of a immunological response to myxosporidian is evident. Our results show the presence of immunodeposits in the basement membrane of the glomeruli, suggesting that they might initiate glomerulonephritis. The lesion was markedly similar to immune complex-mediated glomerulonephritis disease in higher vertebrates.

Animals↗

PubMed1992

Local immune response in the chicken Harderian gland to antigen given by different ocular routes.

The effectiveness of three ocular routes of antigen administration to produce a local immune response in the Harderian gland was studied. The routes were by eyedrop, injection into the ocular conjunctiva and injection into the nictitating membrane. The antigen was observed in the cytoplasm of macrophages located within the lymphoid tissue only after the injection into the nictitating membrane. The numbers of germinal centres and plaque forming cells found in the gland after injection into the nictitating membrane was higher than the numbers observed following the other two ocular applications. These findings indicate that the injection of the antigen into the nictitating membrane is the most effective ocular route for producing a local immune response in the Harderian gland.

Animals↗

PubMed1992

Immunoglobulin classes synthesised by the chicken Harderian gland after local immunisation.

The immunoglobulin (Ig) levels in tears and sera were compared after antigen administration (salmonella O antigen) by eyedrop and injection into the nictitating membrane, to determine the Ig classes synthesised by the plasma cells in the chicken Harderian gland. Samples of tears and sera were collected from immunised and control birds between 24 hours and 24 days after the antigen or sterile saline was administered. Samples were assayed for IgA, IgG and IgM concentrations using radial immunodiffusion. It is suggested that most of the IgG found in tears after local immunisation has an extraglandular origin.

Animals↗

PubMed1992

Immunocytochemical detection of dendritic cell by S-100 protein in the chicken.

Positivity for S-100 protein in paraffin embedded chicken lymphoid tissue was found by using a polyclonal antibody against whole bovine S-100 protein. The S-100 protein-containing cells were observed in the locations which have been reported to contain avian dendritic cells such as the medulla of the bursal follicles, and the germinal centers and T-dependent areas in the spleen, Peyer's patches, caecal tonsil and Harderian gland. Positive cells were also found in the location where ellipsoid associated cell have been described, and between epithelial cells covering the Peyer's patches and the caecal tonsil, as well as between the cells lining the ducts within the Harderian gland. Macrophages were devoid of immunostaining. Our results confirm the location described elsewhere for chicken dendritic cells and indicate that S-100 protein can be considered as a cell marker for the identification of the chicken dendritic cell. Intraepithelial positive cells may be interdigitating dendritic cells in an unusual location (their function being the transport of the antigen from the epithelium to the diffuse lymphoid tissue), or cytotoxic T-lymphocytes which, in mammals, are immunoreactive for S-100 protein.

Animals↗

PubMed1991

Myofibroblasts and myoepithelial cells in the chicken harderian gland.

An electron microscopic study of the myoepithelial cells in the chicken Harderian gland provides evidence that these cells can be transformed into myofibroblasts. After the application of a Brucella ovis suspension in sterile saline onto the eyeball, every 5 minutes for half an hour, myoepithelial cells gradually develop over a 90-minute period the characteristic features of myofibroblasts: bundles of intracytoplasmic microfilament; abundant rough endoplasmic reticulum; prominent Golgi complex; and surface membrane differentiations, that provide attachment to neighbouring epithelial cells. No typical desmosomes are observed. Besides, the intercellular space between epithelial cells and myofibroblasts increases and the basement membrane adjacent to myofibroblasts disappears. Hypoxia is hypothesized to be involved in the transformation of myoepithelial cells into myofibroblasts.

Actin Cytoskeleton↗

PubMed1991

Granulopoiesis in the pineal gland of chickens.

Foci of differentiating heterophilic granulocytes in the pineal gland were studied by light and electron microscopy in chickens, from hatching until 56 weeks of age. Foci of granulopoiesis could be seen in the first 24 hours after hatching. Thereafter, their number and cellular density increased, becoming highest at 2 weeks. From then on, numbers decreased progressively until foci disappeared at 18 weeks. Granulopoietic cells established local associations with fibroblast-like cells. Mature granulocytes reached the bloodstream by the 2 mechanisms described for hematopoietic cells in the bone marrow, either passing between lining cells or through the cytoplasm of lining cells.

Animals↗

PubMedDate not supplied

Ultrastructural localization of a soluble antigen in the chicken Harderian gland.

The relationship between plasma cells, macrophages, B and T cells, dendritic cells, and epithelium in the chicken Harderian gland have been studied by means of ultrastructural localization of the horseradish peroxidase following local immunization. After 5 d, peroxidase activity was found in vesicles located in macrophages and immature plasma cells. On day 7, peroxidase-antiperoxidase complexes were found in vesicles of the epithelial cells lining the secondary ducts and the acini, in the lumina of the ducts, and on the surface of lymphocytes located among these epithelial cells. Dendritic cells showing peroxidase activity on their surface were seen in the subepithelial lymphoid tissue and in the lymphoid follicles. On day 9, peroxidase activity was found as iccosomes on the surface of dendritic cells and lymphoblasts. These results indicate that immature plasma cells in the Harderian gland can take up antigen and may have a role in presenting it to T cells. Further, our results suggest that intraepithelial lymphocytes might be involved in antigen transportation from the epithelium to the subepithelial lymphoid tissue.

Animals↗