An efficient method for immortalization of amniocytes with chromosome abnormalities for renewable application of rare disease sources

Objective: We describe a new method of immortalizing amniocytes with chromosome abnormalities to generate renewable resources for studying rare diseases. Methods: Three methods were investigated by randomly dividing 180 cases of adherent amniocytes into groups A, B, and C. Group A cells were digested with 0.25% trypsin for 10, 20, 30, 60, 90, and 120 mins. Group B and C cells were digested with 0.25% trypsin for 3–5 minutes. Group A and B cells were then transfected with PT67 cell-produced SV40LT. Group C digested cells underwent liposome-mediated SV40LT-transfection. Results: The percentage of clones immortalized by SV40LT transfection in groups A, B, and C were 18.3, 5.0, and 16.7%, respectively, after G418 screening. Group A produced a higher percentage of immortalized clones than did groups B and C, but only significantly differed from group B. The karyotypes and chromosome 13, 18, 21, X, and Y fluorescence signals in transfected cells of all groups were identical to those of the primary cells after passaging for 10–15 generations. Conclusions: The trypsin-mediated SV40LT transfection used in group A can be applied for routine establishment of amniocyte lines to obtain a renewable resource for the study of rare diseases and as quality control materials for prenatal diagnosis.

A Host-Parasite Model for a Two-Type Cell Population

We consider a host-parasite model for a population of cells that can be of two types, A or B, and exhibits unilateral reproduction: while a B-cell always splits into two cells of the same type, the two daughter cells of an A-cell can be of any type. The random mechanism that describes how parasites within a cell multiply and are then shared into the daughter cells is allowed to depend on the hosting mother cell as well as its daughter cells. Focusing on the subpopulation of A-cells and its parasites, our model differs from the single-type model recently studied by Bansaye (2008) in that the sharing mechanism may be biased towards one of the two types. Our main results are concerned with the nonextinctive case and provide information on the behavior, as n → ∞, of the number of A-parasites in generation n and the relative proportion of A- and B-cells in this generation which host a given number of parasites. As in Bansaye (2008), proofs will make use of a so-called random cell line which, when conditioned to be of type A, behaves like a branching process in a random environment.

A Host-Parasite Model for a Two-Type Cell Population

We consider a host-parasite model for a population of cells that can be of two types, A or B, and exhibits unilateral reproduction: while a B-cell always splits into two cells of the same type, the two daughter cells of an A-cell can be of any type. The random mechanism that describes how parasites within a cell multiply and are then shared into the daughter cells is allowed to depend on the hosting mother cell as well as its daughter cells. Focusing on the subpopulation of A-cells and its parasites, our model differs from the single-type model recently studied by Bansaye (2008) in that the sharing mechanism may be biased towards one of the two types. Our main results are concerned with the nonextinctive case and provide information on the behavior, as n → ∞, of the number of A-parasites in generation n and the relative proportion of A- and B-cells in this generation which host a given number of parasites. As in Bansaye (2008), proofs will make use of a so-called random cell line which, when conditioned to be of type A, behaves like a branching process in a random environment.

Mouse Strain Susceptibility to Gonadectomy-Induced Adrenocortical Tumor Formation Correlates with the Expression of GATA-4 and Luteinizing Hormone Receptor

Certain inbred strains of mice, including DBA/2J, develop adrenocortical tumors in response to gonadectomy. Spindle-shaped cells with limited steroidogenic capacity, termed A cells, appear in the subcapsular region of the adrenal gland, followed by sex steroid-producing cells known as B cells. These changes result from unopposed gonadotropin production by the pituitary, but the adrenocortical factors involved in tumorigenesis have not been characterized. GATA-4, a transcription factor normally expressed in fetal, but not adult, adrenocortical cells, was found in neoplastic cells that proliferate in the adrenal cortex of gonadectomized DBA/2J mice. GATA-4 mRNA was detected in the adrenal glands of female mice 0.5 months after ovariectomy and reached a maximum by 4 months. Castrated male mice developed adrenocortical tumors more slowly than gonadectomized females, and the onset of GATA-4 expression in the adrenal was delayed. In situ hybridization and immunohistochemistry revealed GATA-4 mRNA and protein in A and B cells, but not in normal adrenocortical cells. mRNA encoding another factor associated with adrenocortical tumorigenesis, LH receptor (LHR), was detected in A and B cells. In addition, transcripts for P450 17α-hydroxylase/C17-C20 lyase, an enzyme essential for the production of sex steroids, and inhibin-α were found in B cells. Unilateral ovarian regeneration, a phenomenon known to occur in gonadectomized mice, was observed in a subset of DBA/2J mice undergoing complete ovariectomy. In these animals, adrenocortical tumor progression was arrested; A cells and GATA-4 expression were evident, but there was no expression of LHR or P450 17α-hydroxylase/C17-C20 lyase. Strain susceptibility to adrenocortical tumorigenesis (DBA/2J ≫ FVB/N) correlated with the expression of GATA-4 and LHR, implicating these factors in the process of adrenocortical neoplasia in response to continuous gonadotropin stimulation.

THEORY OF MECHANICAL IMMUNOLOGY

Numerous autoimmune illnesses are not only caused by defects of the immune system but may also be caused by defects in anatomical barriers. Morphologically, most of these barriers consist of basal membranes combined with epithelial cells or, more precisely, their cell membranes. In many organs, these barriers are associated with specialized, phagocytizing cells (e.g. histiocytes, macrophages, microglial cells A and B cells in joints). A collapse of these anatomical barriers caused either by mechanical effects (invasion by micro-organisms) or destructive tumor growth, leads to contact between macrophages and the CD4 lymphocytes, with protein structures of the cell interior. In principle, many intracellular structures should be able to function, on this basis, as potential antigens via MHC II. Contact between intracellular structures and the immune system first leads to a restricted local immune reaction and then to local autoantibody production. In order that a systemic immune reaction can take place, the contact between macrophages, CD4 cells and intracellular structures must occur over a long period and with high intensity. As a desirable, remote target, new clinical therapeutic strategies can be developed from this theory, for example, for patients with cell damage. Examples of such illnesses are, amongst others, cardiac infarcts and strokes as well as accident traumas. An immunosuppressive therapy should reduce the immune reply in all the patients mentioned and thus reduce the volume of the cell damage, giving the patient an advantage.