Age-associated thymic involution has considerable physiological impact by inhibiting de novo T-cell selection. This impaired T-cell production leads to weakened immune responses. Yet the molecular mechanisms of thymic stromal adipose involution are not clear. Age-related alterations also occur in the murine thymus providing an excellent model system. In the present work structural and molecular...

During early fetal ontogeny in birds, the epithelial thymic rudiment is colonized by T cell precursors at specific developmentally regulated time intervals (1, 2) . Avian yolk sac, bone marrow, and to a lesser degree, spleen and bursa of fabricius contain hematopoietic cell precursors that are able to migrate to thymic rudiments and give rise to T lymphocytes (2, 3) . In vitro studies using emb...

Background: Thymoma is a rare malignant tumour in adults which originates from thymic epithelial cells. Micronodular thymoma with lymphoid stroma subtype that accounts for about 1% of all cases. Due to the extremely limited number reported cases, clinical guidelines and therapeutic regimens have not yet been established.

Recently, a role of the receptor for advanced glycation endproducts (RAGE) in myasthenia gravis was described. RAGE and its ligand high mobility group box 1 (HMGB1) play key roles in autoimmunity and cancer. To test whether these molecules are involved in patients with thymic abnormalities we applied immunohistochemical analysis in 33 cases of thymic epithelial tumors, comprising 27 thymomas an...

Using a monoclonal antibody (A2B5), which binds to GQ ganglioside, and tetanus toxin, which binds to GD and GT gangliosides, distinct regions of human and rodent thymic epithelial cells have been identified. The lymphoid elements of the thymus do not bind A2B5 or tetanus toxin. The A2B5 and tetanus toxin-binding cells form a network of thymic epithelial cells throughout the thymic subcapsular c...

Thymic epithelial reticular cells together with lymphocytes constitute the thymic parenchyma. Morphologically they are characterized by the stellate aspect forming a cytoreticulum, a large and vesicular nucleus, a tonofilament-rich cytoplasm, and abundance of desmosomes. Besides the role of providing a structural support for lymphocytes, epithelial reticular cells are responsible for the secret...

The thymic microenvironment constitutes a unique cell environment composed of thymic epithelial cells, myoid cells, and bone marrow-derived accessory cells for the differentiation, maturation and selection of T lymphocytes. The histological feature of thymus is markedly dependent on the age of individual and on various negative stimuli. Our study group consisted of fourteen newborns whose thymu...

Secondary and primar neoplasms of the appendix are rare tumors found in approximately 1% appendectomy specimens, with epithelial neuroendocrine being more frequent. (1). Epithelial adenocarcinoma is most common malignancy mucinous (37%) non-mucinous (27%) histological subtypes. We present a clinical case.

Primary anterior mediastinal neoplasms comprise a diverse group of tumors and account for 50% of all mediastinal masses. Thymomas are most common and can be locally invasive and associated with parathymic syndromes. Thymic carcinomas and thymic carcinoids are rare malignancies with a propensity for local invasion and distant metastases. Thymolipomas are benign thymic tumors. The mediastinal ger...