Ligature of the cervical lymph duct in guinea pigs resulted in marked dilatation of the lymphatics draining the thymus and marked reduction of mitosis in the thymus. A decrease of about 50% in the number of mitoses was found in the cortex within one day after ligation and in the medulla within five days after ligation. The thickness of the cortex also decreased rapidly and markedly in direct pr...

Thymus transplants can correct deficiencies of the thymus epithelium caused by the complete DiGeorge syndrome or FOXN1 mutations. However, thymus transplants were never used to correct T cell-intrinsic deficiencies because it is generally believed that thymocytes have short intrinsic lifespans. This notion is based on thymus transplantation experiments where it was shown that thymus-resident ce...

An inverse relation exists between melatonin and androgen in most of the seasonally breeding rodents, but the regulation of their receptors in modulation of immune function has never been reported. The present study accessed the expression pattern of melatonin receptor types (mt1R & mt2R), immune parameters (lymphoid organs weight, leucocyte count, delayed type hypersensitivity and lymphocyte p...

The effect of physiological and pharmacologically induced thymus involution was studied in 12-week-old female C57BL mice. Thymus involution was estimated by measurement of the thymus weight and the ability of thymocytes to induce a graft-versus-host (GvH) reaction at 48 h after delivery or drug administration in comparison with control (virgin, saline-treated) mice. The thymus weight and immuno...

AIMS Electromagnetic fields (EMFs) can act as inducers or mediators of stress response through the production of heat shock proteins (HSPs) that modulate immune response and thymus functions. In this study, we analyzed cellular stress levels in rat thymus after exposure of the rats to a 2.45 GHz radio frequency (RF) using an experimental diathermic model in a Gigahertz Transverse Electromagneti...

A progressive decrease of the restoring effectivity of syngeneic or allogeneic thymus and functional thymoma grafts was observed when the treatment of neonatally thymectomized mice was delayed. Early treatment (5-20 days postthymectomy) was effective, while the number of restored animals was markedly decreased after late treatment (30-50 days postthymectomy). Similar results were obtained with ...

Corticosteroids suppress the humoral antibody response of mice to sheep erythrocytes. This response depends on interactions between thymus-derived helper cells and bone marrow-derived antibody-forming cell precursors (AFC precursors). Previous experiments had shown that spleen cells (a mixture of thymus-derived and marrow-derived cells) were sensitive to corticosteroids while AFC precursors in ...

Cyclic adenosine 3':5'-monophosphate (cyclic AMP) levels were slightly increased in preleukemic AKR mouse thymus cells, compared with nonleukemic thymus cells, but were markedly reduced in leukemic cells. Adenylate cyclase activity rose during the preleukemic and leukemic phases of leukemogenesis. Although the drop of epinephrine-induced stimulation of thymus adenylate cyclase in the preleukemi...

Hematopoietic precursors continuously colonize the thymus where they give rise mainly to T cells, but also to B and dendritic cells. The lineage relationship between these three cell types is unclear, and it remains to be determined if precursors in the thymus are multipotent, oligopotent, or lineage restricted. Resolution of this question necessitates the determination of the clonal differenti...

Congenital osteopetrosis in the mutant rat "op" is accompanied by early atrophy of the thymus gland. The response of thymocytes to concanavalin A and phytohemagglutinin P was greatly diminished at age 28 days, even before pronounced thymic atrophy could be detected. The response of spleen cells to mitogens that stimulate thymus-derived (T) and bone-marrow-derived (B) cells was diminished as ear...