Search results for "thymus"

Anomalous occurrence of immunoreactive calcitonin cells in the thymus of the rat.

1982

In a study of the effect of pinealectomy on thyroid C-cell number, 8 animals out of 66 were found to have thymic tissue in close association with the thyroid. Cells containing immunoreactive calcitonin were found in all of the thyroids but in only one of the 8 pieces of thymus. These cells found in a piece of thymic tissue associated with the right thyroid lobe were located immediately under the capsule and did not form or associate with follicles. Unlike the other animals the rat with thymic calcitonin cells had an unequal distribution of C-cells between the left and right thyroid lobes, but the total number of thyroidal C-cells was the same as that of the other rats. Since the thymus prop…

Propagation of three thymus species by stem cuttings

2006

Many herbs native to the Mediterranean region are grown for ornamental purposes and represent an important segment of the bedding plant industry. Although the majority of Thymus species are used as officinal plants, some of them are also used as ornamental bedding plants to provide aesthetic enhancement of public and private garden beds, porches, patios, balconies. The aim of this research was to study the vegetative propagation of T. capitatus, T. serpyllum and T. vulgaris. To verify the rooting response to exogenous application of auxin, softwood cuttings were either treated with a 500 ppm 1H-indol-3-butyric acid (IBA) solution, or not treated (control). Propagation was performed in an un…

T-cell-derived helper factor allows in vivo induction of cytotoxic T cells in nu/nu mice

1980

T-cell immunocompetence and diversity are thought to be generated in the thymus1,2. This view is based on the findings that (1) T-cell ontogeny is thymus dependent3,4, (2) the major histocompatibility restrictions of T-cell interactions are phenotypically related to the H–2 type of the thymus5–9, and (3) the phenotypic manifestation of H–2-linked immune responsiveness parallels the restriction elements selected in thymus10–12. However, it is unclear whether pre-thymic cells programmed to develop into T cells do already express a receptor diversity, also whether pre-thymic cells have the potential to react against self-antigens, and whether the mechanism of self-tolerance is initiated in the…

Alloreactive and H-2-restricted Lyt 23 cytotoxic T lymphocytes derive from a common pool of antecedent Lyt 123 precursors.

1980

If the collaborative requirement of Lyt 1 T helper cells is bypassed by the Lyt 1 T cell-derived mediator of T help, termed Il-2, upon antigenic stimulation, PNA+ Lyt 123 thymocytes differentiate into either alloreactive or H-2-restricted PNA- Lyt 23 cytotoxic effector cells. Along the differentiation pathway from Lyt 123 leads to 23 effector cells, cytolytic activity is carried out by T cells that still express the Lyt 123 phenotype. The data establish that Lyt 23 CTL are produced by differentiation from antecedent Lyt 123 cells.

T cell-mediated cytotoxic immune responsiveness of chimeric mice bearing a thymus graft fully allogeneic to the graft of lymphoid stem cells

1980

Fully allogeneic, chimeric mice were established by adult thymectomy of (A × B) F1animals, grafting parental A-type thymus under the kidney capsula, followed by lethal (900 rd) irradiation and reconstitution with B parental-type bone marrow cells treated with xenogeneic anti-T cell antiserum plus complement. Following in vivo sensitization with inactivated Sendai virus (SV) suspensions, no virus-specific T cells could be detected within the spleen cells of the mice. Upon stimulation with third-party allogeneic cells in a primary mixed lymphocyte culture, spleen cells of all animals generated alloreactive cytotoxic T lymphocytes (CTL). More interestingly, upon secondary in vitro stimulation …

Impact of thymus on the generation of immunocompetence and diversity of antigen-specific MHC-restricted cytotoxic T-lymphocyte precursors.

1981

Differences between cysteine and homocysteine in the induction of deoxyribose degradation and DNA damage.

2001

The effect of two naturally occurring thiols, such as cysteine and homocysteine, has been examined for their ability to induce deoxyribose degradation and DNA damage. Copper(II) ions have been added to incubation mixtures and oxygen consumption measurements have been performed in order to correlate the observed damaging effects with the rate of metal catalyzed thiol oxidation. Ascorbic acid plus copper has been used as a positive control of deoxyribose and DNA oxidation due to reactive oxygen species. Cysteine or homocysteine in the presence of copper ions induce the degradation of deoxyribose and the yield of 8-hydroxy-2'-deoxyguanosine (8-OHdG), although important differences are observed…

Alternatively spliced transcripts of the thymus-specific protease PRSS16 are differentially expressed in human thymus.

2004

The putative serine protease PRSS16 is abundantly expressed in the thymic cortex and the gene is encoded within the HLA I complex. Although its function is not yet defined, the very restricted expression points to a role in T-cell development in the thymus. In this study, we show that the PRSS16 mRNA is alternatively spliced to generate at least five transcripts. Apart from the full-length sequence, we found two other isoforms with all putative active site residues of the serine protease, suggesting that those variants may also be functional. Semi-quantitative analysis of the splice variants in different tissue samples revealed a strong correlation between the specific formation of alternat…

A study of thyme germplasm in Sicily

2009

hyme is characteristic of the Mediterranean and is of interest for its multifunctional nature. It is widely used in seasoning and flavouring, in herbal products and cosmetics. The versatility of this species means it is also useful in the protection of areas prone to erosion or an ornamental plant when designing low-maintenance gardens. Thyme germplasm constitutes a large part of the wild flora in Sicily and is a potentially useful source of genetic variability. On the basis of this, in the two-year period from 2004-2005, research was carried out on wild thyme accessions. These were used to evaluate both its productivity and individual biotypes with the functional characteristics most sough…

Inter-laboratory validation of procedures for measuring 8-oxo-7,8-dihydroguanine/8-oxo-7,8-dihydro-2’-deoxyguanosine in DNA.

2002

The aim of ESCODD, a European Commission funded Concerted Action, is to improve the precision and accuracy of methods for measuring 8-oxo-7,8-dihydroguanine (8-oxoGua) or the nucleoside (8-oxodG). On two occasions, participating laboratories received samples of different concentrations of 8-oxodG for analysis. About half the results returned (for 8-oxodG) were within 20% of the median values. Coefficients of variation (for three identical samples) were commonly around 10%. A sample of calf thymus DNA was sent, dry, to all laboratories. Analysis of 8-oxoGua/8-oxodG in this sample was a test of hydrolysis methods. Almost half the reported results were within 20% of the median value, and half …