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 AccessApoptosis in gallbladder carcinomas and dysplasias, its relation to the expression of caspases 3,6 and 8 and apoptosis regulating proteins bcl-2, mcl-l and bax(Murcia : F. Hernández, 2000) Turunen, N.; Paakko, P.; Solni, Y.In this study we investigated apoptosis and the expression of caspases 3, 6 and 8 and bcl-2, mcl-l and bax in 39 gallbladder carcinomas and 7 epithelia1 dysplasias. The average apoptotic index was 0.68+0.91%. The extent of apoptosis was higher in grade 11-111 than grade I tumours or epithelial dysplasias (p=0.003). Also, tumours invading beyond serosa or into other organs (T3-T4) had a higher apoptotic index than other tumours (p=0.05). Caspase 3 expression was found in 37 (95%) and caspase 6 and 8 expression each in 30 (77%) carcinomas. Their expression associated with each other and tended to increase along with the progression of the lesions. Bcl-2 expression was found in only 4 (10%) tumours. In contrast, mcl-l positivity was found in 34 (87%) and bax positivity in all cases. The results show that apoptosis is increased along with progression of the neoplastic lesion of the gallbladder epithelium. Caspases 3,6 and 8 are strongly expressed in gallbladder carcinomas suggesting that they contribute to the increased apoptosis observed in them. Of the bcl-2 family proteins, bcl-2 was expressed infrequently suggesting that it does not play any significant role in apoptosis inhibition in gallbladder tumours.
- 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.
- 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 AccessElastin variations implicating in vascular smooth muscle cells phenotype in human tortuous arteries(Murcia : F. Hernández, 2000) Ortiz, P.P.; Sarrat, R.; Daret, D.; Whyte, J.; Torres, A.; Daniel-Lamaziere, J.M.The aim of the present work was to study the morphological implications between the elastin and the phenotypic expression of the vascular smooth muscle cells. For this purpose, sixty human tortuous arteries from different territories have been studied. We have measured the morphometric indexes Intimal Thickening Index and Elastolyse Index and they have been quantified with computer system analysis, image-colour corresponding to the orcein and Verhoeff reactions for detecting elastin and the a-actin in the smooth muscle cells. We compared both territorial arteries from the cranial and from abdominal origin. The elastin concentration was similar in both territories, but not its morphology according to its spatial distribution. We have observed a relationship between the elastin structural organisation from the media of arteries and of the internal elastic lamina in these territories and the variation of reactivity to the smooth muscle a-actin as a marker of the phenotypic state. Our results confirm the hypothesis that elastin, besides intervening in the architecture of the arterial wall, is a factor implicated in the phenotypic variability of the smooth muscle cells and in the development and evolution of the intimal thickenings in human atherosclerosis.