			Home About us Contact

Human Tonsils (human + tonsil)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Abstract no.: 10 DNA fragmentation, but not caspase-3 activation or PARP-1 cleavage, combined with macrophage immunostaining as a tool to study phagocytosis of apoptotic cells in situ

FUNDAMENTAL & CLINICAL PHARMACOLOGY, Issue 3 2006
Dorien M. Schrijvers
Efficient phagocytosis of cells undergoing apoptosis by macrophages is important to prevent immunological responses and development of chronic inflammatory disorders, such as systemic lupus erythematosus, cystic fibrosis or atherosclerosis. To study phagocytosis of apoptotic cells (AC) by macrophages in tissue, we validated different apoptosis markers (DNA fragmentation, caspase-3 activation and cleavage of its substrate poly (ADP-ribose) polymerase-1) in combination with macrophage immunostaining. Human tonsils were used as a model because they show a high apoptosis frequency under physiological conditions as well as efficient phagocytosis of AC by macrophages. On the other hand, advanced human atherosclerotic plaques were examined since phagocytosis of AC in a plaque is severely impaired. Our results demonstrate that the presence of non-phagocytized TUNEL-positive AC represents a suitable marker for poor phagocytosis by macrophages in situ. Other markers for apoptosis, such as cleavage of caspase-3 or PARP-1, should not be used to assess phagocytosis efficiency, because activation of the caspase cascade and cleavage of their substrates can occur in AC when they have not yet been phagocytized by macrophages. [source]

Optical-thermal simulation of tonsillar tissue irradiation

LASERS IN SURGERY AND MEDICINE, Issue 4 2001
Rahul K. Shah MD
Abstract Background and Objective Despite laser applications targetted toward tonsillar tissue, there has been no characterization of underlying optical and thermal events during laser irradiation of tonsillar tissue. Study Design/Materials and Methods The optical properties of canine and human tonsils were determined at 805 nm (diode laser) and 1,064 nm (Nd:YAG laser). An optical-thermal simulation was developed to predict the temperature rise in irradiated human tonsils. Results The optical properties of human and canine tonsillar tissue are similar at both wavelengths. The optical-thermal simulation was validated and predicts that at 10 W and 1 minute of irradiation, the heat will be contained within the human tonsil. The diode laser causes more superficial heating than the Nd:YAG laser. Conclusions The safety of irradiating human tonsils was shown. The diode laser is superior to the Nd:YAG laser because less heat affects collateral structures. The optical-thermal simulation detailed in this study can be used to predict the temperature rise in tissues undergoing irradiation. Lasers Surg. Med. 28:313,319, 2001. © 2001 Wiley-Liss, Inc. [source]

CD5+ B cells with the features of subepithelial B cells found in human tonsils

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2007
Mariella Dono
Abstract This study describes a CD5+ B cell that differs from the majority of the CD5+ B cells from human tonsils. This cell, isolated from in vivo activated B cells, expressed activation markers and featured a CD23,, IgMhigh, IgDlow surface phenotype, responded to T cell-independent type-2 antigens in vitro, and was detected in the subepithelial (SE) areas, the tonsil equivalent of the splenic marginal zone (MZ). Most of the cells utilized unmutated Ig VH genes, although cells with mutated genes also were found, a finding confirmed by single-cell studies. Mutated sequences were more frequent in suspensions enriched for CD27+ cells. Repeated VDJ gene sequences were observed in different molecular clones from the same cell suspension, suggesting in situ expansion. These CD5+ B cells seem to share features with previously characterized tonsil CD5, SE B cells and differ from the majority of tonsil CD5+ B cells, which have the surface phenotype of follicular mantle B cells, lack activation markers, do not respond to T cell-independent antigens, and utilize unmutated VH genes. These data are discussed considering the present views on the origin of B cell subset populations and the relationships between MZ and B1 cells. [source]