Showing papers by "Université catholique de Louvain published in 1983"
TL;DR: Tissue distribution, blood clearance and excretion of biodegradable cyanoacrylic nanoparticles, and the enzymatic contribution to the degradation of the nanoparticles in vivo are described.
313 citations
TL;DR: The development of the cross decomposition method captures profound relationships between primal and dual decomposition, and shows that the more constraints can be included in the Langrangean relaxation, the fewer the Benders cuts one may expect to need.
Abstract: Many methods for solving mixed integer programming problems are based either on primal or on dual decomposition, which yield, respectively, a Benders decomposition algorithm and an implicit enumeration algorithm with bounds computed via Lagrangean relaxation. These methods exploit either the primal or the dual structure of the problem. We propose a new approach, cross decomposition, which allows exploiting simultaneously both structures. The development of the cross decomposition method captures profound relationships between primal and dual decomposition. It is shown that the more constraints can be included in the Langrangean relaxation (provided the duality gap remains zero), the fewer the Benders cuts one may expect to need. If the linear programming relaxation has no duality gap, only one Benders cut is needed to verify optimality.
179 citations
TL;DR: A role for the human liver in selective removal of p-IgA from plasma is supported, but another mechanism than the SC-dependent biliary transport should be considered.
Abstract: We have studied the relative contributions of monomeric (m-) and polymeric IgA (p-IgA) and of IgA1 and IgA2 to total serum IgA in healthy adults and patients with liver disease (LD) or with other diseases and high serum IgA. Serum concentration of total secretory component (SC) was also determined. In addition, fractional catabolic rates (FCR) and synthetic rates for both m- and p-IgA were measured in nine controls and nine cirrhotics. Our results support four main conclusions: (a) In healthy adults, intravascular p-IgA contributes to only 4-22% (mean 12%) of serum IgA, because its FCR and synthetic rate are approximately two times higher and four times smaller, respectively, than those of intravascular m-IgA. (b) in LD, biliary obstruction does not result in a significant increase in serum p-IgA unlike in rats and rabbits, indicating that in humans the SC-dependent biliary transport of p-IgA plays a much less significant role in selective removal of p-IgA from plasma than in rats and rabbits. (c) In contrast to biliary obstruction, parenchymal LD results in a significant and preferential increase in serum p-IgA, which in cirrhotics correlates with a selective reduction of the p-IgA-FCR. This supports a role for the human liver in selective removal of p-IgA from plasma, but another mechanism than the SC-dependent biliary transport should be considered. (d) Total SC, p-IgA, and IgA2 in serum are unlinked parameters, not necessarily reflecting mucosal events. A marked increase in serum SC occurs almost selectively in LD. Although a shift to IgA2 is suggested in Crohn's disease and alcoholic cirrhosis, a shift to IgA1 frequently associated to a shift to p-IgA occurs in chronic active LD, primary Sicca, and connective tissue diseases.
175 citations
TL;DR: In this article, the spectrum of the ground state nonets, JPC = (0, 1, 2)−+; 1−− is calculated in the MIT bag model including O(αs) energy shifts.
159 citations
TL;DR: In human brain, [3H]ketanserin was found to bind on serotonin (5-HT) S2-receptors; only 5-HT antagonists competed with the labelled ligand at nanomolar concentrations; other drugs were much less active or inactive.
141 citations
TL;DR: Analysis of the correlations between serum lipids and plasma lipolytic enzymes suggests that the mechanism of the hypolipidaemic action of clofibrate and bezafibrate might be related to increased catabolism of triglyceride-rich particles; that of fenofibrates and probucol was less clear and might be multifactorial in origin.
Abstract: Ten male, normolipaemic, non-obese subjects were given clofibrate 2g daily, fenofibrate 300 mg daily, bezafibrate 600mg daily and probucol 1g daily for eight days, in a crossover study with a wash-out period of 4–8 weeks between each drug regimen. Clofibrate, fenofibrate and bezafibrate caused a significant decrease in serum triglycerides, total cholesterol and LDL-cholesterol concentrations. Probucol caused a significant increase in serum LDL-cholesterol concentration. Serum HDL-cholesterol concentration was significantly increased by bezafibrate and significantly decreased by probucol. All drugs but probucol led to a significant rise in the activity of the plasma lipoprotein lipase; there was not a significant increase in the activity of plasma hepatic lipase after any drug. The activity of plasma lecithin: cholesterol acyltransferase was significantly increased by fenofibrate and probucol. Analysis of the correlations between serum lipids and plasma lipolytic enzymes suggests that the mechanism of the hypolipidaemic action of clofibrate and bezafibrate might be related to increased catabolism of triglyceride-rich particles; that of fenofibrate and probucol was less clear and might be multifactorial in origin.
137 citations
TL;DR: The distributions of the individual results suggest that about 1-2% of the daily meals sampled had mercury and cadmium contents that exceeded the tolerable level proposed by WHO; in the case of lead this level was exceeded in 10%.
131 citations
TL;DR: The uptake of transferrin-bound iron by cultured mammalian cells involves receptor-mediated endocytosis and internalization of thetransferrin-receptor complex, followed by iron release in an intracellular acidic vesicle.
130 citations
TL;DR: In this article, the mechanism of action of organic nucleating agents such as sodium benzoate and its derived salts completely differs from the generally accepted model, at least in the case of polyesters.
Abstract: Several attempts1–5 have been made to control the rate of crystallization and the morphology by the addition of very finely-divided substances which promote abundant nucleation. However, these studies have mostly been carried out on an empirical basis and, except in a few cases (self-seeding6, epitaxy2–5), the mechanism of action of these nucleating agents is poorly understood despite several attempts at modelling1,2. This is particularly so in the case of most technical nucleating agents such as mica, talc and organic salts. We report here that the mechanism of action of organic nucleating agents such as sodium benzoate and its derived salts completely differs from the generally accepted model, at least in the case of polyesters. The nucleating agent reacts as a true chemical reagent with the molten macromolecules and produces ionic end groups which constitute the true nucleating species.
122 citations
TL;DR: In this paper, the authors discuss numerical methods for evaluating key characteristics of posterior and predictive density functions, as well as analytical methods remain indispensable to evaluate these densities, either fully or conditionally on a few parameters amenable to numerical treatment.
Abstract: Publisher Summary This chapter discusses the Bayesian inference and identification. A Bayesian analysis of the scanning electron microscope (SEM) proceeds along the same lines as any other Bayesian analysis. Thus, if the analyst has chosen to work in a given parameter space, a prior density on that space is defined and Bayes theorem is applied to revise this prior density in the light of available data. The resulting posterior density is then used to solve problems of decision and inference. Predictive densities for future observations can also be derived. The chapter discusses numerical methods for evaluating key characteristics of posterior and predictive density functions. For models with many parameters, such as most simultaneous equation models, analytical methods remain indispensable to evaluate these densities—either fully, or conditionally on a few parameters amenable to numerical treatment, or approximately to construct importance functions for Monte Carlo integration. The classes of prior densities permitting analytical evaluation of the posterior density are limited. In most Bayesian analyses they comprise essentially the so-called noninformative and natural-conjugate families.
120 citations
TL;DR: These are the first confirmed cases, outside East Asia, of human illness due to rat-borne Hantaan-like virus, and of infection in laboratory rats, in staff handling laboratory rats on a Belgian university campus.
TL;DR: On demontre des theoremes d'existence pour les solutions 2π-periodiques de l'equation x″+f(x)x'+g(t,x)=e(t), avec f continue, g Caratheodory and e Lebesgue integrable sous certaines hypotheses as mentioned in this paper.
Abstract: On demontre des theoremes d'existence pour les solutions 2π-periodiques de l'equation x″+f(x)x'+g(t,x)=e(t), avec f continue, g Caratheodory et e Lebesgue integrable sous certaines hypotheses
TL;DR: In this paper, a numerical scheme for the determination of the fiber orientation state in dilute suspensions is developed, based on the numerical integration of Jeffery's orienta tion equation along the streamlines obtained on the basis of the finite element method.
Abstract: A numerical scheme for the determination of the fiber orientation state in dilute suspensions is developed. Fiber orientations are calculated from the numerical integration of Jeffery's orienta tion equation along the streamlines obtained on the basis of the finite element method. Numerical solutions of the fiber orientation state are presented for the simple shear flow, the fountain flow and the flow in an infinite expansion.
TL;DR: In this article, the influence of the bulk P/V ratio of V-P-O catalysts on their phase composition, surface P/v ratio and catalytic activity for n-butane partial oxidation is reported.
TL;DR: Pyrophosphate—fructose‐6‐ph phosphate 1‐phosphotransferase was the only enzyme present in a tuber extract which was found to be sensitive to fructose 2,6‐bisphosphate, which could not be explained by an increase in the concentration of fructose 6‐ phosphate or of ATP.
TL;DR: In this paper, aphasic subjects' verbal behavior is impaired, but they produce more speech-related gestures than normals, while non-aphasic participants produce fewer gestures.
Abstract: Samples of free conversations were recorded in 6 normal and 12 aphasic subjects. Manual activity during speech was observed. Groups were shown to behave in an opposite way for the verbal and nonverbal measures: while aphasic subjects' verbal behavior is impaired, they produce more speech-related movements than normals. No differences appear concerning other movements (automanipulation, hand-to-hand posture, miscellaneous movements). Analysis of the aphasie group reveals no difference between the fluent and the nonfluent aphasies. Verbal fluency is shown to be a non-critical factor in the explanation of gesture production. Increased gestural production in aphasies may be interpreted according to the hypothesis that gestures are cues for the difficulties the speaker experiences in the verbal encoding process.
On a recueilli des echantillons de conversation spontanee chez six sujets normaux et douze aphasiques. L'activite manuelle accompagnant la parole a ete analysee. Les groupes different en sens oppose selon les mesures, verbales ou non-verbales: perturbes dans leur comportement verbal, les aphasiques produisent plus de gestes que les sujets normaux. Aucune difference ne se manifeste en ce qui concerne les autres mouvements (automanipulation du visage, des mains et mouvements divers). L'analyse du groupe aphasique ne montre aucune difference entre les aphasiques fluents et non-fluents. La fluidite verbale ne parait donc pas constituer le facteur essentiel dans l'explication de la production gestuelle. L'augmentation de la gesticulation chez les aphasiques peut etre interpretee dans le cadre de l'hypothese selon laquelle les gestes sont des indices des difficultes que le locuteur eprouve dans les processus d'encodage verbal.
TL;DR: Visual fixation and pursuit abilities of human infants were tested during their first year of life and show that the fixation of visual targets is accomplished by a head rotation accompanied by a series of small eye saccades.
TL;DR: It is found that the c-myc gene was rearranged in four of five immunocytomas carrying the characteristic chromosomal translocation in human Burkitt's lymphoma and murine plasmacytoma and in rats of a third species, the rat.
Abstract: Two B-cell-derived tumours, human Burkitt's lymphoma (BL) and murine plasmacytoma (MPC), are regularly associated with a distinctive form of chromosomal translocation (for reviews see refs 1, 2) In BL, the distal portion of chromosome 8 breaks off and is transposed, in most cases, to chromosome 14, known to carry the immunoglobulin heavy-chain locus In about 5% of the cases the same distal part of the chromosome 8 has moved to either chromosome 2 or 22, to the neighbourhood of the kappa or the lambda locus, respectively In MPC the distal region of chromosome 15 is transposed to the chromosome 12, known to carry the immunoglobulin heavy-chain locus, or enters into reciprocal exchange with the kappa locus-carrying chromosome 6 (ref 7) Several laboratories have located c-myc, the cellular homologue of the MC29 retroviral oncogene v-myc, to human chromosome 8 (refs 8-10) and mouse chromosome 15 (refs 11-13) It has also been shown that the BL- and MPC-associated translocations remove the c-myc gene from its original site and transpose it into or close to one of the immunoglobulin gene clusters In view of the above findings we also looked for possible involvement of the c-myc gene in a B-cell-derived tumour of a third species, the rat Rat immunocytomas of spontaneous origin carry a reciprocal translocation between chromosomes 6 and 7 (ref 17) Here we have localized the c-myc locus to chromosome 7 of the rat Moreover, we have found that the c-myc gene was rearranged in four of five immunocytomas carrying the characteristic chromosomal translocation
TL;DR: In this article, stable state and time-dependent finite element simulations have been generated to represent transport phenomena in a Czochralski melt, and three basic convection mechanisms, previously recognized in the literature, have been verified.
TL;DR: In this paper, the structure and representations of the rotation reflection symmetry group of the four-dimensional cubic lattice are described and connections with the representations of three-dimensional lattice rotation reflection group, and with the representation of the continuous O(3) and O(4) groups are given.
TL;DR: The major rat liver microsomal esterases acting on o-nitrophenylacetate with isoelectric points 5.0, 5.5, 6.1 and 6.2 behaved as monomers except the pI-6.1 enzyme which behaved as a trimer, and two enzymes were inducible by phenobarbital.
Abstract: The major rat liver microsomal esterases acting on o-nitrophenylacetate with isoelectric points 5.0, 5.5, 6.1 and 6.4 were resolved by isoelectric focusing. Molecular weights were determined by sedimentation analysis in isokinetic gradients of sucrose and, after purification, in sodium dodecyl sulphate/polyacrylamide gel electrophoresis. Their subunit molecular weights were between 57 000 and 60 000. They behaved as monomers except the pI-6.1 enzyme which behaved as a trimer. Esterases of pI 5.0, pI 6.1 and pI 6.4 behaved like glycoproteins of the polymannose type in the presence of 125I-labelled concanavalin A. Preparations of the pI-5.0 enzyme contained two esterases of highly homologous structure. Antibodies directed against this preparation did not inhibit but precipitated pI-5.0 esterase activity quantitatively. They did not react with the pI-6.1 and pI-6.4 esterases but precipitated several nonimmunologically related esterases. Two of these enzymes were inducible by phenobarbital. Total activity was very low in 3-day-old animals. Individual esterase activities rose at different rates during development; the enzyme focusing near pI 5.0 was about three times more active in adult females than in males. All microsomal esterases are located on the luminal side of the endoplasmic reticulum.
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TL;DR: In this article, it was shown that the problem of deciding whether or not a point ξ ∈ R|b can be written as a convex combination of the incidence vectors of the trees of a finite undirected graph G can be solved by computing a minimum cut, i.e., by carrying out at most n − 2 maximum flow calculations where n is the number of nodes of G and |E the total number of edges of G.
Abstract: We show that the problem of deciding whether or not a point ξ ∈ R|b can be written as a convex combination of the incidence vectors of the trees of a finite undirected graph G can be solved by computing a minimum cut, i.e., by carrying out at most n – 2 maximum flow calculations where n is the number of nodes of G and |E the number of edges of G.
TL;DR: The results indicate that proliferation of bacteria already present on the teeth accounts for the major part of the microbial mass increase during early plaque formation, and that the mean generation time is shorter during the first 8 hours than during the following 16 hours.
Abstract: Plaque growth may be a result of proliferation of bacteria already present on the teeth and/or of a continuous deposition of additional salivary bacteria. The purpose of this investigation was to study the relative significance of these two mechanisms.
During 4, 8, or 24 hours, plaque was allowed to form on plastic films placed on the buccal surface of the premolar 14 of subjects with healthy gingiva. In addition plastic films were used to collect plaque for an initial 4 hour period after which a filter was applied to prevent further bacterial aggregation to the deposits. The filter-covered plastic films remained in situ for another 4 or 20 hours. After removal, the samples were processed for electron microscopy.
After 4 hours, the plastic films were covered by a surface coating of an acellular material in or on which bacteria, epithelial cells, and leukocytes were observed. The 8-hour samples exhibited the same general morphology, but contained more cellular components. After 24 hours, the plaque consisted mainly of a multilayer of bacteria. The 4-hour samples which remained in the mouth for an additional 4-hour period covered by a filter resembled the 8-hour samples. Furthermore, the samples which were covered by the filter after 4 hours and allowed to remain for another 20 hours in the mouth were very similar to the 24-hour samples.
Finally, the number of bacteria present in a specified area in the section along the plastic film adjacent to the gingival margin was counted in one section from each sample. These data indicated that the number of bacteria had increased between 4 and 8 hours, but no difference was noted between the number of bacteria originating from the 8-hour samples with or without filter. For the period between 4 and 24 hours, an obvious increase in bacterial counts was ascertained.
The results indicate that proliferation of bacteria already present on the teeth accounts for the major part of the microbial mass increase during early plaque formation, and that the mean generation time is shorter during the first 8 hours (1–2 hours) than during the following 16 hours (3–7 hours).
TL;DR: It is concluded that, in the 129/Sv mouse, RF production during secondary immune responses is a physiological phenomenon.
Abstract: The involvement of rheumatoid factor (RF)-secreting cells in normal immune responses was examined by screening hybridomas derived from 129/Sv mice during primary and secondary immune responses against foreign proteins. No RF-secreting cells were detected during primary responses, but up to 10% of the total number of clones obtained during secondary responses produced IgM with anti-IgG activity. Like typical mouse RF, these anti-IgG autoantibodies had a strict isotypic specificity, mostly for IgG1, and a much stronger avidity for immune complexes than for native IgG. The selective activation of IgG1-specific RF during these secondary immune reactions was not due to fortuitous antigenic similarities between mouse IgG1 and the antigens used for immunization, nor did it result from the use of adjuvants for priming, or from contamination of antigen preparations with lipopolysaccharide. It is therefore concluded that, in the 129/Sv mouse, RF production during secondary immune responses is a physiological phenomenon.
TL;DR: A rapid carbachol‐induced disappearance of muscarinic cell surface receptors was shown using [3H]methyl scopolamine as ligand on intact 108CC15 hybrid cells or rat cerebellar cells, which could represent the first event in cell desensitization which could be followed by receptor recycling in physiological conditions or by receptor degradation if the stimulation by agonists persists, as in long‐term regulation.
TL;DR: Reconstitution experiments of irradiated naïve C57BL/6 mice with various combinations of syngeneic antibody against human transferrin and primed or unprimed spleen cells indicated that important RF responses could be induced only when antigen was injected into mice that had received both antibody and immune spleen Cells.
Abstract: Production of IgM rheumatoid factor (RF) during secondary immune responses was studied in normal mouse strains by measuring RF synthesis in spleen cell cultures. A considerable, although transient, RF response was observed in BALB/c and C57BL/6 mice immunized and i. v. boosted with various protein antigens and with sheep erythrocytes. With most antigens, RF production equalled or exceeded that of antigen-specific IgM, but it peaked and subsided earlier. No RF production was detected when either priming or boosting was omitted. The isotypic specificity of RF depended upon the antigens used for immunization: all proteins tested stimulated the synthesis of RF specific for IgG1, whereas sheep erythrocytes induced both IgG1- and IgG2a-specific RF. Reconstitution experiments of irradiated naive C57BL/6 mice with various combinations of syngeneic antibody against human transferrin and primed or unprimed spleen cells indicated that important RF responses could be induced only when antigen was injected into mice that had received both antibody and immune spleen cells.
TL;DR: If the blood concentration of tetrachloroethylene does not exceed 1 mg/1,16 h after the end of exposure, the time-weighted average exposure is likely to have been below 50 ppm, which does not seem to exert any adverse effect on the central nervous system, the liver and the kidney.
Abstract: Behavioral, renal, hepatic and pulmonary tests were applied to 22 subjects exposed to tetrachloroethylene in 6 dry-cleaning shops. The results were compared with those obtained in 33 subjects non-occupationally exposed to organic solvents. The intensity of exposure was monitored by personal environmental monitoring and by urine analysis for trichloroacetic acid and expired air and venous blood analysis for tetrachloroethylene. The time-weighted average exposure to tetrachloroethylene amounted to 21 ppm (range 9 to 38 ppm). The correlation between the concentration of tetrachloroethylene in ambient air sampled with the charcoal tube method and with a passive dosimeter indicates that the latter can correctly estimate the time-weighted average exposure to the solvent. In view of the long biological half-life of tetrachloroethylene, the internal dose may be better estimated by measuring its concentration in blood 16 h after the end of exposure (i.e. before resuming work the next morning). The present study suggests that if the blood concentration of tetrachloroethylene does not exceed 1 mg/1,16 h after the end of exposure, the time-weighted average exposure is likely to have been below 50 ppm. Exposure to such level for 6 years on the average does not seem to exert any adverse effect on the central nervous system, the liver and the kidney.
TL;DR: It is concluded that the pma locus, affected by these mutations, is the structural gene either for the 100000-Mr subunit of plasma membrane ATPase or for a protein which tightly controls the conformation of the plasma-membrane ATPase within the membrane.
Abstract: Mutations affecting the plasma membrane ATPase of Saccharomyces cerevisiae were obtained by selecting mutants resistant to Dio-9. In a plasma-membrane-enriched fraction of the mutant MG2130, the ATPase activity was resistant to vanadate (50% inhibition by 26 microM in the mutant compared to 1.3 microM in the parental strain). Several catalytic properties of the membrane-bound ATPase were modified by 60-120% in the mutant which had a higher Km for MgATP and was more heatstable, less sensitive to mercurials, and more stimulated by monovalent cations than the parental type. A single mutation is responsible for the phenotypes of four independent allelic mutants. Resistance to Dio-9 in vivo and resistance to vanadate in vitro segregated together in three tetrads issued from a cross between the wild type and mutant. The mutation is semi-dominant as shown by expression of the mutant phenotype in a heterozygous diploid resulting from the cross between the wild type and mutant. It is concluded that the pma locus, affected by these mutations, is the structural gene either for the 100000-Mr subunit of plasma membrane ATPase or for a protein which tightly controls the conformation of the plasma-membrane ATPase within the membrane.