The thymus in autoimmune Myasthenia Gravis: Paradigm for a tertiary lymphoid organ.

In autoimmune Myasthenia Gravis (MG), a neuromuscular disease generally mediated by autoantibodies against the acetylcholine receptor (AChR), the muscle is the target organ of the autoimmune attack, while the thymus seems to be the primary production site of the autoantibodies. In the majority of patients with anti-AChR antibodies, it is characterized by the presence of germinal centers, which contain B cells that produce anti-AChR antibodies. In this review, we summarize recent results regarding neoangiogenic processes, cell infiltration and modified chemokine expression in the MG thymus, which are typical features of secondary lymphoid organs. The structural and functional changes in the MG thymus therefore allow us to declare it to be an archetype for tertiary lymphoid neogenesis providing optimal settings for the interaction between lymphocytes and antigen presenting cells in order to elicit an immune response. We further discuss factors that may have a key role in the transformation of the MG thymus into a tertiary lymphoid organ, such as IFN type I and dsRNA signaling. These factors could also be of importance in other autoimmune diseases, especially those characterized by tertiary lymphoid neogenesis.

Human ovarian tissue cryopreservation: quality of follicles as a criteria of effectiveness.

Experiments comparing vitrification and conventional freezing of mammalian ovarian tissue show that vitrification can also guarantee the storage of viable follicles after warming, but conventional freezing is more effective. The central goal of cryotechnology is the preservation of intact follicles. This article presents a critical opinion about the normality of follicles after vitrification of human ovarian tissue and microbial contamination as a result of direct contact of this tissue with liquid nitrogen at vitrification.

Short-term effects of IGF-I and estradiol on LH secretion from female rat gonadotrophs.

OBJECTIVE: Growth factors and ovarian steroids modulate LH-secretion from pituitary gonadotrophs. Our previous studies demonstrated that long-term IGF-I treatment enhanced LH-secretion from female rat pituitary cells and estradiol facilitated this effect. The effects of estradiol on LH secretion are time-dependent. Short-term treatment inhibited, long-term treatment enhanced GnRH-induced LH-secretion in serum-containing medium. Here we tested the short-term actions of IGF-I and its interaction with estradiol and whether IGF-I is a prerequisite for the negative effect of short-term estradiol treatment in female rat pituitary cells. DESIGN: Pituitary cells were incubated with a series of increasing concentrations of estradiol (1 pM, 10 pM, 50 pM, 100 pM, 500 pM, 1 nM, 10 nM and 100 nM) for 4 h, IGF-I (10 pM, 100 pM, 1 nM and 10 nM) for 4 h and 14 h and their combinations for 4h in serum-free medium, and then stimulated with 1 nM GnRH during the last 3h of incubation. To clarify the role of IGF-I, cells were incubated simultaneously with estradiol, IGF-I and antibody against IGF-I. LH was measured by radioimmunoassay. RESULTS: Short-term IGF-I treatment did not modify basal or GnRH-induced LH-secretion. Short-term treatment with estradiol did not affect basal or GnRH-induced LH-secretion in serum-free medium. The addition of 100 pM IGF-I to serum-free medium established the negative effect of estradiol short-term treatment on GnRH-induced LH-secretion. The addition of IGF-I antibody fully abolished the negative effect of estradiol. CONCLUSIONS: In conclusion, effects of IGF-I on LH-secretion in female rat pituitary cells require long-term treatment. The negative effect of estradiol short-term treatment on GnRH-induced LH-secretion is dependent on serum-containing medium or the addition of 100 pM IGF-I to serum-free medium.