Histology and histopathology Vol.15, nº 1 (2000)
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- PublicationOpen AccessThe visualization of oxidant stress in tissues and isolated cells(Francisco Hernández, Professor of Cell Biology, University of Murcia, Murcia, Spain, 2000) Frank, J.; Biesalsk, H. K.; Dominici, S.; Pompella, A.Many studies have implicated the role of oxidant stress in a wide range of human diseases and have led to the rapid expansion of research in this area. With many experimental approaches a direct detection of the production of reactive oxygen species (ROS) and free radicals is not possible. Free radicals are very reactive, short-lived and react in a non-specific way, so that ongoing oxidative damage is generally analyzed by measurement of secondary products e.g. H2O2, "oxidized" proteins, peroxidized lipids and their breakdown products, "oxidized" DNA or by fluorographic analysis in combination with fluorescent dyes e.g. dichlorofluorescin (DCFH). The histochemical visualization of selected molecular markers for oxidative phenomena can often provide valuable information concerning the distribution of oxidative processes in vivo. A number of biochemical methods are available for the monitoring of almost all oxidant stress-related processes, although their applicability in vivo is limited. This review summarizes the biochemical methods currently available for histochemical detection and indirect visualization of an excess of free radicals and ROS. The cited methods are discussed and the results obtained from their application are critically evaluated.
- PublicationOpen AccessCatenins and their associated proteins in colorectal cancer(Murcia : F. Hernández, 2000) Tucker, E.L.; Pignatelli, M.Colorectal cancer is the second most common cause of cancer mortality in the western world. Colorectal cancer has been well studied, and the genetic steps involved in the adenoma to carcinoma sequence have been well elucidated. The first genetic alteration, found in 85% of adenomas, are mutations in the adenomatous polyposis coli (MC) gene. However, the consequences of this and the exact function of APC in the colon is not fully understood. It has been suggested that APC could function through its regulation of Bcatenin, an ubiquitous cytoskeletal protein with multiple binding specificities resulting in diverse functions including cell growth, adhesion, and migration. Any change in these associations may play a role in colorectal cancer development and progression.
- PublicationOpen AccessThe female prostate and prostate-specific antigen. lmmunohistochemical localization, implications of this prostate marker in women and reasons for using the term "prostate" in the human female(Murcia : F. Hernández, 2000) Zaviacic, M.; Ablin, R.J.Prostate-specific antigen (PSA) is currently the most frequently used marker for the identification of normal and pathologically altered prostatic tissue in the male and female. Immunohistochemically PSA is expressed in the highly specialized apically-superficial layer of female and male secretory cells of the prostate gland, as well as in uroepithelial cells at other sites of the urogenital tract of both sexes. Unique active moieties of cells of the female and the male prostate gland and in other parts of the urogenital tract are indicative of secretory and protective function of specialized prostatic and uroepithelial cells with strong immunological properties given by the presence of PSA. In clinical practice, PSA is a valuable marker for the diagnosis and monitoring of diseases of the male and the female prostate, especially carcinoma. In the female, similarly as in the male, the prostate (Skene's gland) is the principal source of PSA. The value of PSA in women increases in the pathological female prostate, e.g., carcinoma. Nevertheless, the total amount of PSA in the female is the sum of normal or pathological female prostate and non-prostatic female tissues production, e.g., of diseased female breast tissue. The expression of an antigen specific for the male prostate, i.e., PSA in female Skene's glands and ducts, and structural and functional parameters and diseases similar to that of the male prostate, have provided convincing evidence of the existence of a prostate in women and definitive preference of the term "prostate" over that of Skene's glands and ducts. The use of the term Skene's glands incorrectly implies that some other structure rather than prostate is involved, promoting the vestigial position of this female organ.
- PublicationOpen AccessRole of myofibroblasts during normal tissue repair and excessive scarring:Interest of their assessment in nephropathies(Murcia : F. Hernández, 2000) Badid, C.; Mounier, N.; Costa, A.M.A.; Desmoulière, A.Following injury, tissue repair process takes place involving inflammation, granulation tissue formation and scar constitution. Granulation tissue develops from the connective tissue surrounding the damaged area and contains vessels, inflammatory cells, fibroblasts and myofibroblasts. Myofibroblasts play an important role in many tissue injuries and fibrocontractive diseases. The process of normal wound repair after tissue injury follows a closely regulated sequence including the activation and the proliferation of fibroblastic cells. In pathological situations, the normal resolution stages are abrogated and the proliferation of myofibroblasts continues, inducing excessive accumulation of extracellular matrix. The differentiation of fibroblastic cells into myofibroblasts is an early event in the development of tissue fibrosis. Myofibroblastic cells express smooth muscle cytoskeletal markers (asmooth muscle actin in particular) and participate actively in the production of extracellular matrix. The evaluation of myofibroblast differentiation in renal biopsies would be useful for histopathologists to appreciate the intensity of tissue injury and particularly to predict the long term outcome of some nephropathies. Immunohistochemical studies for a-smooth muscle actin should be made systematically in renal tissue biopsies. Myofibroblastic differentiation appears to play a significant role in the progression of renal failure and seems to be a useful marker of progressive disease.
- PublicationOpen AccessCurrent understanding of macrophage type 1 cytokine responses during intracellular infections(Murcia : F. Hernández, 2000) Xing, Z.Macrophages are important effector cells in cell-mediated immunity against intracelllular infection. Among cytokines that macrophages are able to release are IL-12 and TNFa. IL-12 is a critical linker between the innate and adaptive cell-mediated immunity, capable of Thl differentiation and IFNy release by T and NK cells. IFNy is critically required for the activation of macrophage bactericidal activities. Recently emerging evidence suggests that macrophages are able to release not only IL-12 and TNFa but also IFNy. However, the mechanisms that control the release of each of these type 1 cytokines in macrophages appear different. While macrophages release TNFa in an indiscriminate and IL- 12-independent way, the release of IL-12, particularly bioactive IL-12 p70, and IFNy is under tight control. We are just beginning to understand what controls the release of IL-12 p70, a question of fundamental importance to understanding the mechanisms underlying the initiation of cell-mediated immunity. Our recent findings have shed more insights into the regulatory mechanisms of macrophage IFNy responses. It has become evident that IL-12 is required not only for Thl differentiation but also for IFNy responses by both T cells and macrophages during intracellular infection. In this overview, we have discussed about the current understanding of the regulation of macrophage type 1 cytokine responses during intracellular infection, based upon the recent findings from us and others.