Cell-induced Modification

The earliest recognizable lesion of atherosclerosis is the fatty streak, an a egation of lipid-rich macrophages and 

Evidence from cellular studies in vitro initially showed how oxidative processes could play a central role in the pathological changes involved in the genesis of atherosclerosis. LDL can be oxidatively modified in culture by a range of cell types including endothelial cells (Henriksen et a.1., 1981), arterial smooth muscle cells 

IN CULTURE BY CELLS OF TYPE LOCATED IN ARTERY WALL 

Transition metals, or haem Proteins and Ruptured Erythrocytes and Myocytes 

Injury to cells and tissues may enhance the toxicity of the active oxygen species by releasing intracellular transition metal ions (such as iron) into the surrounding tissue from storage sites, decompartmentalized haem proteins, or metalloproteins by interaction with delocalized proteases or oxidants. Such delocalized iron and haem proteins have the capacity to decompose peroxide to peroxyl and alkoxyl radicals, exacerbating the initial lesion. 

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Parthasarathy, S., Steinbrecher, U.P., Barnett, J., Witztum, J.L. and Steinberg, D. (1985). Essential role of phospholipase A2 activity in endothelial cell-induced modification of low density lipoprotein. Proc. Natl Acad. Sci. USA 82, 3000-3004. 

The cytotoxicity of LDL can also be inferred from the study by Blake et al. (1985). In this study of human cultured endothelial cells, stored sera from patients with necrotizing arteritis demonstrated an enhanced tendency to develop oxidized LDL, which correlated closely with endothelial cell cytotoxicity. This process appears to require the presence of both oxygen and transition metal ions such as iron in the presence of a reducing agent (Gebicki ef /., 1991). There is considerable evidence that transition metals are involved in cell-induced modifications of LDL including the inhibitory effects of EDTA and desfer-rioxamine (Hiramatsu et 1987). A role for Of in LDL modification by endothelial cells and fibroblasts comes from studies showing inhibition of LDL oxidation by SOD (Steinbrecher, 1988). 

Generalized Two-Dimensional (2D) correlation analysis is a powerful tool applicable to data obtained from a very broad range of measurements, such as chromatography or infrared spectroscopy. Relationships among systematic variations in infrared spectra are obtained as a function of spectroscopic frequencies. In this paper, the variation is induced by the introduction of small doses of CO in the catalytic cell, inducing a pressure change and a modification of adsorbed CO concentration. The correlation intensities are displayed in the form of 2D maps, usually referred to as 2D correlation spectra. 2D correlation analysis can help us to solve the complexity of the spectra... 

The variation of the unit cell parameters versus temperature is reported in Figure 2. For the as-synthesized sample, at room temperature, the cell parameter are a=7.5675, b=l 8.1187, c=26.0605 A and the cell volume is 3573.2 A3. In the first step of heating (T <120 °C) only small variation of the cell parameters are shown. The volume variation is mostly due to the c parameter shortening, since it is the most subjected to temperature induced modifications. Between 120 and 360 °C a remains almost constant, c decreases of 0.1%, while b slightly increase-up to 215 °C- and subsequently regains its initial value. The combination of these variations leads an inflection in the volume contraction, slowing down its decrease. Above 390 °C the cell volume remains almost constant and only minor variations in the parameters are observed. The final values obtained after the refinement at 715 °C accounted a variation of -0.25, +0.07, -0.77 and -0.95% for a, b, c and V respectively. The minor variation of the cell parameters above 450 °C indicates that at this temperature the dehydration process is almost fulfilled. The TG curve in flowing air shows that the total mass variation of the as-synthesized phase is 15.8%. Dehydration process is almost fulfilled at about 500 °C above this temperature only... 

UV-C technology is widely used as an alternative to chemical sterilization and microorganism reduction in food products (Lamikanra 2002 Fan and others 2008). Ultraviolet light also induces biological stress in plants and defense mechanisms in plant tissues with the consequent production of phytochemical compounds (Lee and Kader 2000). Phytoalexin accumulation could be accompanied by other inducible defenses such as cell-wall modifications, defense enzymes, and antioxidant activity, which have been reported with health benefits (Gonzalez-Aguilar and others 2007). It is well documented that UV-C irradiation has an effect in secondary metabolism. 

Abscisic acid is a negative regulator in that it primarily antagonizes the action of cytokinins, auxins, and in particular, gibberellins. Abscisic acid decreased the activity of polymerase in radishes (52), peas (53), maize coleoptiles (54), and pear embryos (55). More detailed studies are needed before the question of ABA-induced "modification" of RNA polymerase (54) or "alterations" in the number of sites for template activity (56) can be answered. In barley aleurone cells, ABA-induced suppression of GA-induced <-amylase formation was presumed to involve the continuous synthesis of a short-lived RNA (57). 

Colquhoun, A. and Schumacher, R.I., Gamma-linolenic acid and eicosapentaenoic acid induce modifications in mitochondrial metabohsm, reactive oxygen species generation, lipid peroxidation and apoptosis in Walker 256 rat carcinosarcoma cells, Biochim. Biophys. Acta, 1533, 207, 2001. 

Monocytes migrate from the endothelium to the intima and differentiate into macrophages. The oxidation of LDL by free radicals generated by smooth muscle cell endothelial cells and macrophages, induces modifications to both the lipid and protein moieties of the lipoprotein particle. 

Complex interactions and displacements of the omega-3 and omega-6 fatty acids take place in plasma and cellular lipids after dietary manipulations. Early steps of cell activation, such as generation of inositol phosphates, are induced by dietary fatty acids (Galli et al., 1989). The effects of dietary fatty acids on the inositol phosphate pathway indicate that diet-induced modifications of PUFA at the cellular level affect the activity of the enzymes responsible for the generation of lipid mediators in addition to the formation of products (eicosanoids) directly derived from their fatty acid precursors. This shows that dietary fats affect key processes in cell function. 

ECM is facilitated by small hyaluronic acid molecules implies a function in host defense, but has not been proven (106). Increased levels of hyaluronic acid were associated with colon inflammation, psoriasis, osteoarthritis, rheumatoid arthritis, and scleroderma (101,107,108), as well as with viral infections (109). Hyaluronic acid is produced by endothelial cells and binds to its receptor, CD44, expressed by activated T and B cells, inducing the attachment of the two cell types (110). This interaction is controlled by the expression of specific hyaluronic acids sub-types or by modifications of CD44 on platelets (111). High molecular weight hyaluronic acid and CD44 are essential for scarless embryonic wound repair (112). 

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