Search results for "Pois"
showing 10 items of 1683 documents
Topotecan-triggered degradation of topoisomerase I is p53-dependent and impacts cell survival.
2005
Abstract The anticancer drug topotecan belongs to the group of topoisomerase I (topo I) inhibitors. In the presence of topotecan, topo I cleaves the DNA but is unable to religate the single-strand break. This leads to stabilization of topo I-DNA–bound complexes and the accumulation of DNA strand breaks that may interfere with DNA replication. The molecular mechanism of controlling the repair of topo I-DNA covalent complexes and its impact on sensitivity of cells to topotecan is largely unknown. Here, we used mouse embryonic fibroblasts expressing wild-type p53 and deficient in p53, in order to elucidate the role of p53 in topotecan-induced cell death. We show that p53-deficient mouse embryo…
Optimization of a GF-AAS method for lead testing in blood and urine: A useful tool in acute abdominal pain management in emergency.
2021
Suspicion of lead poisoning is confirmed by its concentration in blood and protoporphyrin red blood cells. At low concentrations, lead influences the synthesis of the heme in the sense of lowering it. Acute and chronic lead intoxication is extremely polymorphic in regards to its clinical manifestations, with digestive, hematological, cardiovascular, renal hepatic and neurological features. The aim of the study was to evaluate the presence of lead in human whole blood and urine harvested before and during chelation treatment in the case of lead poisoning. An atomic absorption spectroscopic method for the analysis of lead was developed using graphite furnace atomic absorption spectrophotomete…
Volumetric changes of articular cartilage during stress relaxation in unconfined compression
2000
The time-dependent lateral expansion and load relaxation of cartilage cylinders subjected to unconfined compression were simultaneously recorded. These measurements were used to (1) test the assumption of incompressibility for articular cartilage, (2) measure the Poisson's ratio of articular cartilage in compression and (3) investigate the relationship between stress relaxation and volumetric change. Mechanical tests were performed on fetal, calf, and adult humeral head articular cartilage. The instantaneous Poisson's ratio of adult cartilage was 0.49+/-0.08 (mean+S.D.), thus confirming the assumption of incompressibility for this tissue. The instantaneous Poisson's ratio was significantly …
Causalidad en salud laboral: el caso ardystil
1995
ResumenEl establecimiento de relaciones causa-efecto ha sido y sigue siendo objeto de debate en epidemiología. La naturaleza observacional de la investigación epidemiológica dificulta el reconocimiento de estas relaciones. En este contexto, se han propuesto diferentes modelos para explicar las relaciones causales en los procesos de salud y enfermedad, desde el modelo determinista puro defendido por los postulados de Koch, que requiere la aceptación de relaciones unicausales, pasando por otras explicaciones que asumen la naturaleza multicausal de los problemas de salud en la población. En Salud Laboral se debe disponer también de modelos explicativos y criterios consensuados para valorar las…
Polyketides from the marine-derived fungus Aspergillus falconensis: In silico and in vitro cytotoxicity studies.
2020
Abstract Fermentation of the marine-derived fungus Aspergillus falconensis, isolated from sediment collected from the Red Sea, Egypt on solid rice medium containing 3.5% NaCl yielded a new dibenzoxepin derivative (1) and a new natural isocoumarin (2) along with six known compounds (3–8). Changes in the metabolic profile of the fungus were induced by replacing NaCl with 3.5% (NH4)2SO4 that resulted in the accumulation of three further known compounds (9–11), which were not detected when the fungus was cultivated in the presence of NaCl. The structures of the new compounds were elucidated by HRESIMS and 1D/2D NMR as well as by comparison with the literature. Molecular docking was conducted fo…
Synthesis and biological evaluation of a D-ring-contracted analogue of lamellarin D
2017
A D-ring contracted analogue of the strongly cytotoxic marine pyrrole alkaloid lamellarin D was synthesized and investigated for its antiproliferative action towards a wild type and a multidrug resistant (MDR) cancer cell line. The compound was found to inhibit tumor cell growth at submicromolar concentrations and showed a lower relative resistance in the MDR cell line than the antitumor drug camptothecin to which lamellarin D shows cross resistance and with which lamellarin D shares the same binding site.
Synthesis and Antitumor Properties of 2,5-Bis(3'-indolyl) thiophenes: Analogues of Marine Alkaloid Nortopsentin
2007
A series of 11 bis-indolylthiophenes of formula I were obtained by cyclization of bis-indole 1,4-diketones using Lawesson''s reagent. Derivs. I (R = OMe, R1 = SO2Ph), I (R = OMe, R1 = Me), I (R = Cl, R1 = Me), and I (R = OMe, R1 = H) were selected to be evaluated in the full panel of about 60 human tumor cell lines derived from nine human cancer cell types and showed antiproliferative activity generally in the micromolar range. The most sensitive cell lines were: CCRF-CEM, MOLT-4, HL60 (TB), and RPMI-8226 of the leukemia subpanel, HT29 and HCC-2998 cell lines of the colon sub-panel, NCI-H522 of the non-small cell lung cancer sub-panel, LOX IMVI of the melanoma sub-panel, and UO-31 of the re…
Path integral solution for non-linear system enforced by Poisson White Noise
2008
Abstract In this paper the response in terms of probability density function of non-linear systems under Poisson White Noise is considered. The problem is handled via path integral (PI) solution that may be considered as a step-by-step solution technique in terms of probability density function. First the extension of the PI to the case of Poisson White Noise is derived, then it is shown that at the limit when the time step becomes an infinitesimal quantity the Kolmogorov–Feller (K–F) equation is fully restored enforcing the validity of the approximations made in obtaining the conditional probability appearing in the Chapman Kolmogorov equation (starting point of the PI). Spectral counterpa…
Probabilistic response of nonlinear systems under combined normal and Poisson white noise via path integral method
2011
In this paper the response in terms of probability density function of nonlinear systems under combined normal and Poisson white noise is considered. The problem is handled via a Path Integral Solution (PIS) that may be considered as a step-by-step solution technique in terms of probability density function. A nonlinear system under normal white noise, Poissonian white noise and under the superposition of normal and Poisson white noise is performed through PIS. The spectral counterpart of the PIS, ruling the evolution of the characteristic functions is also derived. It is shown that at the limit when the time step becomes an infinitesimal quantity an equation ruling the evolution of the pro…
Charged particles at fluid interfaces as a probe into structural details of a double layer
2011
Electrostatic interactions between charged, distant colloids in a bulk electrolyte solution do not depend on the inherent structure of ions and a solvent forming a double layer. For charged colloids trapped at an interface between an electrolyte and air this no longer holds; as the electrostatic interactions are mediated via air and the field lines determining the interactions originate at the charged surface, these details come into prominence. Using the Langevin-Poisson-Boltzmann equation we investigate how steric effects and the polarization saturation of a solvent effect the contact potential at the colloid surface and, in consequence, the long range interactions between colloids trappe…