A compared study on the purification of fetal and adult rat hepatocyte suspensions by biomagnetic isolation techniques and flow cytometry analysis.

An analysis of liver cell populations from both adult and 21 day pregnancy rat fetuses (E21) was carried out. The results show that E21 hepatocytes express OX-43, as do endothelial cells but not adult hepatocytes. OX-43 could be used in future as a cell marker for the hepatocyte maturation.

Optimization of the technique to isolate fetal hepatocytes, and assessment of their functionality by transplantation.

In contrast to adult hepatocytes, fetal hepatocytes (FH) are thought to be highly proliferative less immunogenic and more resistant to both cryopreservation and ischemic injury. In the present study, we describe the method for isolation of FH and the relationship between the transplantability of FH into the spleen of analbuminemic rats and expression of albumin mRNA. Rat FH were obtained using the nonperfusion collagenase/DNase digestion method. Nagase analbuminemic rats (NAR), a strain which bears a mutation that determines the impossibility of the normal splicing of the albumin mRNA were used as recipients. The transplanted FH immediately migrated to the liver via portal vein, and anchored there. To assess the functional state of the transplanted cells, one month after transplantation, the expression of the albumin gene was studied in the liver of the recipients.

Ultrastructural changes in the spleen of the natterjack, Bufo calamita, after antigenic stimulation.

In the present study comparative aspects of the ultrastructure of the spleen were analyzed in non-immunized and T-dependent antigen-challenged natterjacks, Bufo calamita. Special attention is focused on the role of the non-lymphoid components in the splenic immunoreactivity. Ten days after primary immunization with sheep erythrocytes, splenic lymphoid follicles increase considerably in number and size. By that time, lymphoblasts, medium and large lymphocytes abound in the periphery of the white pulp near the marginal zone. Meanwhile, in the red pulp numerous monocytes migrating across the sinusoidal walls apparently transform into giant, dendritic-like cells. Twenty days after immunization the splenic lymphoid follicles decrease in number, although certain reactivity persists and numerous plasma cells occur in the cell cords and sinusoids of the red pulp. These results are discussed comparatively with those reported in other lower vertebrates.

Non-lymphoid cells of the anuran spleen: an ultrastructural study in the natterjack, Bufo calamita.

The present study is concerned with the ultrastructure of the spleen in the natterjack, Bufo calamita (Anura, Bufonidae), with special emphasis on the structure and function of the non-lymphoid elements occurring in the red and white pulp. The organ consists of two clearly distinguishable areas, the white and the red pulp, separated by a prominent marginal zone. Thus, the pattern of lymphocytic arrangement in the spleen of Bufo calamita corresponds to a follicular model and is similar to that reported in the primitive anurans of the Pipidae family, such as Xenopus laevis. The white pulp presents a reticular network consisting of two different cell types and free cells, such as lymphocytes, plasma cells, and macrophages. The red pulp is formed by cell cords, where reticular cells and fibers, macrophages and lymphocytes occur, and blood sinuses which sometimes contain developing erythroid elements. Colloidal carbon particles injected via the lymph sac are trapped exclusively by free macrophages in the red pulp which then move through the marginal zone to the white pulp. Giant, ramified, non-phagocytic cells appear in both white and red pulp. They have been functionally related with the trapping of antigen-antibody complexes on their surface, and a possible dendritic significance is discussed on the basis of their morphologic characteristics.