Histology and histopathology Vol.10, nº 1 (1995)
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- PublicationOpen AccessVessel wall-dependent metabolic pat hways of the(Murcia : F. Hernández, 1995) Preissner, K.T.; Pötzsch, B.The integrity of the vessel wall under quiescent conditions as well as its appropriate responsiveness under conditions of stimulation, inflammation or vascular injury is controlled by a number of adhesive interactions involving distinct cellular receptor systems and various multifunctional adhesive ligands. While a number of these extracellular matrix components of the vessel wall are endogenously produced, secreted and deposited, exogenous adhesion proteins may become translocated from the intra- to the extravascular space by virtue of endothelial cell-specific transport systems. Two prominent examples for each metabolic pathway are discussed. Endothelial cellspecific biosynthesis and secretion as well as deposition of multimeric von-Willebrand-factor within intracellular granules (Weibel-Palade bodies) relates to the first possibility of processing, whereas binding of reactive forms of circulating vitronectin to diverse cellular receptors with subsequent extravasation and deposition into the extracellular matrix appears to be characteristic for the second case. In this review the known features of the metabolic routes of both adhesion proteins are discussed and set in perspective to their functional properties. Their localized mode of action in the vessel wall appears to be crucial for balanced haemostasis and immune systems, two major defence mechanisms of the organism.
- PublicationOpen AccessEffects of various antineoplastic agents on-2(Murcia : F. Hernández, 1995) García Reverte, Juana María; Bernabeu-Esclapez, A.; Muñoz Ramos, J.; Vicente Ortega, Vicente; Canteras Jordana, ManuelAn established human melanoma cell line was treated with severa1 concentrations of three antineoplastic drugs: melphalan (0.01 6, 0.032, 0.16 pn), CCNU (1- (2-chloroethy1)-3-cyclohexyl1-- nitrosourea) (0.04, 0.21, 0.42 pM) and 4-OHA (4-hydroxyanisole) (4.01 x 1 0-4, 1 . 2 0~1 0 -2~.,4 ~ pM), and the effects on cell growth and viability were compared. 24 hours after treatment, 4-OHA ( 1 ~ ~ ~ = 2 . 4 ~ 1 0 - ~ pM) was more cytotoxic than melphalan (ID50=0.016 pM) and CCNU (ID50=0.21 pM). However. after 96 hours exposure, the most effective drug was CCNU (growth rate = -1.277), which caused the death of the culture. This was followed by melphalan (growth rate = - 1.024) and finally 4-OHA (growth rate= -0.69). Similar ultrastructural cell injuries were observed after the use of the three drugs: the dilation of endoplasmic reticulum vesicles and the nuclear membrane; mitochondria swelling; and the existence of lamellar structures and cytoplasmic vacuoles.
- PublicationOpen AccessEpithelial-to-mesenchymal change of differentiation.(Murcia : F. Hernández, 1995) Guarino, M.ln embryonic morphogenesis, dramatic changes from one state of differentiation to another take place, and some epithelia transform into mesenchymal cells endowed with the ability to migrate and to form connective tissue. In vitro model systems have been developed which have provided new insights into crucial aspects of this differentiation change. Triggered perhaps by either extracellular matrix or growth factors. this phenotypic conversion involves a reorganization of the cytoskeleton, and changes in both cell-cell and cellmatrix interactions. As embryonic and adult tissues contain the same, albeit differently expressed, genetic information, one could expect, under particular circumstances, conversion to mesenchyme from epithelium to occur in adult tissues too. Indeed, there is evidence that this change really occurs in human diseases: some tissue reactions to injury: the process of tumour invasion and metastasis; and the development of carcinosarcomas, are al1 pathological conditions in which an epithelial conversion into mesenchyme probably plays a role. Here, recent observations on embryonic and in vitro epithelialmesenchymal conversion are reviewed. and these data are compared with findings from some pathological situations. Many similarities emerge which further strengthen the belief that this change in differentiation is involved in the pathogenesis, and underlies the pathological pattern of some diseases.
- PublicationOpen AccessLesions in lambs experimentally infected(Murcia : F. Hernández, 1995) Masot, A.J.; Gázquez, A.; Regodón, S.; Franco, A.; Redondo, E.An experimental model was designed to characterize lesions in the lung of lambs inoculated with bovine respiratory syncytial virus (BRSV). 25 Merino lambs of both sexes, with a live weight of 17+3 Kg, received an intratracheal inoculation of 20 m1 saline solution containing 1 . 2 6l~o 6 TCIDSOB RSV (strain NMK-7) per ml. Lambs were laughtered 1, 3, 7, 11 and 15 postinoculation days (PID), and histopathological, immunohistochemical and electron microscopic studies were performed. Results reflected a series of lesions, the most noteworthy of which were bronchiolitis obliterants with destruction of the mucociliary apparatus, the presence of syncytial cells in alveoli and a progressive interstitial reaction. BRSV antigen was detected in lung samples. These changes might be expected to decrease the efficiency of respiratory tract defence mechanisms, rendering the lung parenchyma susceptible to opportunist bacteria1 infection.
- PublicationOpen AccessEffects of bombesin on the morphology and(Murcia : F. Hernández, 1995) Malendowicz, L.K.; Nussdorfer, G.G.; Miskowiak, B.; Majchrzak, M.The acute and chronic effects of bornbesin (BM) on the structure and function of rat adrenal cortex were investigated by rnorphornetric and radioirnrnunological techniques. An intraperitoneal bolus injection of 2 yglrat BM rnarkedly raised plasma corticosterone (B) concentration (PBC). The intraperitoneal BM infusion (1 yg/rat.h-l) for 1, 2 or 4 days evoked a notable increase in the nurnber of adrenocortical cells, without inducing apparent changes in either PBC or B output by adrenal quarters. Since proliferation and expression of specialized functions are rnutually exclusive states of cells, our findings suggest that the conspicuous stirnulation of adrenocortical-cell proliferation evoked by BM infusion may be responsible for the apparent lack of effect of this treatrnent on B secretion.