Search results for "STRESS"
showing 10 items of 6278 documents
Plasma corticosteroids, free fatty acids, insulin and glucose in maternal blood during delivery.
1970
Plasma-corticosteroids (PCS), free fatty acids (FFA), insulin and glucose were determined continously in maternal blood during the entire course of delivery, from the first stage of labour until 6 hours after delivery. A steep increase in the PCS and FFA concentration could be noticed from the onset of labour (PCS: 37,8±11.2 µg/100 ml;\(s_{\bar x} \),p≦0.01; FFA: 556±106.6 µVal/l;\(s_{\bar x} \),p≦0.01) to the birth of the child (PCS: 96.8±19,5 µg/100 ml;\(s_{\bar x} \),p≦0.01; FFA: 1129±220 µVal/l;\(s_{\bar x} \),p≦0.01) and basal levels were already reached 6 hours later (PCS: 36.0±18.5 µg/100 ml;\(s_{\bar x} \),p≦0.01; FFA: 538±192.8 µVal/l;\(s_{\bar x} \),p≦0.01). The rise of insulin an…
Oxidant stress: the role of nutrients in cell-lipoprotein interactions
1999
Oxidant stress is increasingly becoming an important hypothesis to explain the genesis of several pathologies, including cancer, atherosclerosis and also ageing. Beside a few rare genetic defects, dietary factors are thought to play a key role in the regulation of the production of reactive oxygenated species. An imbalance between nutrients, and in particular those involved in antioxidant status, could explain the onset of an enhanced production of free radicals. We will briefly review information concerning oxidation of lipids and lipoproteins which lead to atherothrombosis. We also present new findings supporting a role for blood platelets in generating oxidant species. New data are also …
Haemostasis in chronic kidney disease
2013
The coagulation system has gained much interest again as new anticoagulatory substances have been introduced into clinical practice. Especially patients with renal failure are likely candidates for such a therapy as they often experience significant comorbidity including cardiovascular diseases that require anticoagulation. Patients with renal failure on new anticoagulants have experienced excessive bleeding which can be related to a changed pharmacokinetic profile of the compounds. However, the coagulation system itself, even without any interference with coagulation modifying drugs, is already profoundly changed during renal failure. Coagulation disorders with either episodes of severe bl…
Novel α2β1 integrin inhibitors reveal that integrin binding to collagen under shear stress conditions does not require receptor preactivation.
2012
The interaction between α2β1 integrin (GPIa/IIa, VLA-2) and vascular collagen is one of the initiating events in thrombus formation. Here, we describe two structurally similar sulfonamide derivatives, BTT-3033 and BTT-3034, and show that, under static conditions, they have an almost identical effect on α2-expressing CHO cell adhesion to collagen I, but only BTT-3033 blocks platelet attachment under flow (90 dynes/cm(2)). Differential scanning fluorimetry showed that both molecules bind to the α2I domain of the recombinant α2 subunit. To further study integrin binding mechanism(s) of the two sulfonamides, we created an α2 Y285F mutant containing a substitution near the metal ion-dependent ad…
Synthesis and characterization of Sn(IV) complexes of lower rim 1,3-diacid derivative of calix[4]arene and their protective effects on tissue oxidati…
2005
The two Sn(IV) complexes synthesized using calix[4]arene-1,3-di-acid derivative were characterized by analytical, 1H, 13C and 119Sn NMR, matrix assisted laser desorption ionization mass, and 119Sn Mossbauer techniques and found that the complexes are tetranuclear possessing structurally two different types of tin centers. These complexes were evaluated for their protective value against blood and tissue oxidative stress in lead exposed male albino rats of Wistar strain. The results suggest that the two tin complexes significantly protect changes in lead induced biochemical variables indicative of heme synthesis pathway and exhibit only moderate effect on tissue oxidative stress. The benefic…
Enhanced platelet thromboxane synthesis and reduced macrophage-dependent fibrinolytic activity related to oxidative stress in oral contraceptive-trea…
1996
Abstract In previous studies conducted in rats and in women, we have shown that oral contraceptive (OC) administration induced a platelet hyperaggregation simultaneously with an increased platelet lipid biosynthesis which might be related to lipid peroxidation. In the present study, we specifically studied the arachidonic acid and the fibrinolytic pathways in relation to the fatty acid composition in female rats treated for 6 weeks with OC (ethinyl estradiol plus lynestrenol). We found that platelets of treated animals were not only hyper-responsive to thrombin and ADP, but also to sodium arachidonate. In addition, the results of the thrombin-induced release of labeled arachidonic acid pre-…
Folic Acid Deficiency Enhances Oral Contraceptive-Induced Platelet Hyperactivity
1997
Abstract In previous studies conducted in female rats and in women, oral contraceptives (OC) were found to induce a platelet hyperactivity that was related to an oxidative stress. Because cases of megaloblastic anemia have been reported to occur in women taking OC, these treatments are suspected of depleting folate stores. In the study presented herein, which was conducted in rats, we sought to determine the influence of dietary folic acid deficiency (FD) on the thrombogenicity of OC. Animals were fed for 6 weeks with either a folic acid-deficient diet (250 μg/kg folic acid) or a control diet (750 μg/kg). One-half of the animals in each group were treated with OC (ethinyl estradiol plus ly…
Heme oxygenase-1 induction and regulation in unstimulated mouse peritoneal macrophages
2003
Heme oxygenase-1 (HO-1) is a stress protein induced by a variety of stimuli in inflammatory cells. This study was set up to investigate the induction of this protein in unstimulated macrophages. Resident mouse peritoneal macrophages purified by adhesion and cultured in basal conditions strongly induced HO-1 in a time-dependent manner, with a peak at 20 hr. At the same time, low levels of nitrite accumulated in the culture medium and expression of nitric oxide synthase-2 (NOS-2) and NOS-3 protein was detected. Inhibition of NO production and/or NOS expression by incubating macrophages with different drugs inhibiting NOS activity or modulating the redox state of the cell, such as N-acetylcyst…
The mechanically-based approach to 3D non-local linear elasticity theory: Long-range central interactions
2010
Abstract This paper presents the generalization to a three-dimensional (3D) case of a mechanically-based approach to non-local elasticity theory, recently proposed by the authors in a one-dimensional (1D) case. The proposed model assumes that the equilibrium of a volume element is attained by contact forces between adjacent elements and by long-range forces exerted by non-adjacent elements. Specifically, the long-range forces are modelled as central body forces depending on the relative displacement between the centroids of the volume elements, measured along the line connecting the centroids. Further, the long-range forces are assumed to be proportional to a proper, material-dependent, dis…
The finite element method for the mechanically based model of non-local continuum
2011
SUMMARY In this paper the finite element method (FEM) for the mechanically based non-local elastic continuum model is proposed. In such a model each volume element of the domain is considered mutually interacting with the others, beside classical interactions involved by the Cauchy stress field, by means of central body forces that are monotonically decreasing with their inter-distance and proportional to the product of the interacting volume elements. The constitutive relations of the long-range interactions involve the product of the relative displacement of the centroids of volume elements by a proper, distance-decaying function, which accounts for the decrement of the long-range interac…