Showing papers by "University of Turin published in 1983"
TL;DR: In this paper, a discussion of equazioni funzionali in the context of uniforme uniforme locale and the prolungamento of an operatore is presented.
Abstract: Nell’ambito della teoria delle equazioni funzionali nel senso di J. Aczel e della loro stabilita secondo D H. Hyers, si espongono alcuni risultati e problemi concernenti l’approssimazione uniforme locale e il prolungamento di un operatoref:D
f
⊂ ℝ →X (X spazio di Banach) per il quale sia verificata la condizione ‖f(x+y)−f(x)−f(y)‖ 0, oppure ‖f(x+y)+f(x−y)−2f(x)−2f(y)‖<δ, su un sottoinsieme assegnato di ℝ2.
526 citations
Journal Article•
TL;DR: Results indicate that HEC in culture are able to release platelet-activating factor and that metabolic pathways similar to those described for leukocytes are involved.
Abstract: The release of platelet-activating factor (PAF) from stimulated human endothelial cells (HEC) cultured from normal term, umbilical cord veins is described. HEC in primary cultures released PAF after challenge with A23187, rabbit anti-human factor VIII (RaHu/FVIII), angiotensin II, and vasopressin. HEC subcultures maintained the ability to release PAF in the presence of A23187 and RaHu/FVIII, whereas the release of PAF in response to angiotensin II and vasopressin was not constant and was reduced. Control cultured, smooth muscle cells derived from umbilical cord veins, previously depleted of endothelial cells, did not release PAF under the above-mentioned stimulation. Plastic-adherent or cultured monocytes released PAF with A23187, but not with RaHu/FVIII, angiotensin II, and vasopressin. The release of PAF from HEC in primary cultures required the presence of extracellular cations and the activation of membrane phospholipase A2. PAF release induced by A23187, RaHu/FVIII, angiotensin II, and vasopressin was unaffected by indomethacin, an inhibitor of cyclooxygenase, which, however, favored the release of PAF from HEC stimulated with thrombin, a stimulus that did not affect HEC in the absence of indomethacin. PGI2 inhibited PAF release from stimulated HEC. The relevance of an acetylation process in the biosynthesis of PAF and HEC was supported by the following evidence: 1) the increase in PAF yield in the presence of sodium acetate and, particularly, of acetyl-CoA; 2) the incorporation of [14C]acetate into PAF molecules; 3) the loss of radioactivity and of biologic activity after treatment with phospholipase A2. These results indicate that HEC in culture are able to release PAF and that metabolic pathways similar to those described for leukocytes are involved.
410 citations
29 Aug 1983
TL;DR: Graph models have been proposed by many authors as a useful tool for the analysis of peculiar features of computer systems such as concurrency, synchronization, communication, and cooperation among subsystems.
Abstract: Graph models have been proposed by many authors as a useful tool for the analysis of peculiar features of computer systems such as concurrency, synchronization, communication, and cooperation among subsystems. Much of the work in this field is related to the original ideas developed by C. A. Petri. These graph models are today generally known as Petri Nets (PNs).
159 citations
TL;DR: In this article, a computational scheme for the treatment of Coulomb sums in the Hartree-Fock approach to periodic systems in one, two, and three dimensions is presented, where the interaction of two charge distributions contributing to the total charge in cells is treated exactly at short range.
Abstract: A computational scheme for the treatment of Coulomb sums in the Hartree-Fock approach to periodic systems in one, two, and three dimensions is presented. The philosophy is as follows: (a) The interaction of two charge distributions contributing to the total charge in cells $\stackrel{\ensuremath{\rightarrow}}{0}$ and $\stackrel{\ensuremath{\rightarrow}}{\mathrm{m}}$ is treated exactly at short range; (b) when the reciprocal penetration of the distributions is sufficiently small, the charge distribution at $\stackrel{\ensuremath{\rightarrow}}{\mathrm{m}}$ is partitioned into "shell-charge distributions" which are then expanded in a multipole series; (c) for $|\stackrel{\ensuremath{\rightarrow}}{\mathrm{m}}|$ larger than a given threshold, a Madelung sum of atomic charges is performed. Results are reported for the $\mathrm{S}{\mathrm{N}}_{x}$ polymer, the graphite, boron nitride, and beryllium monolayers, for the beryllium monolayer with hydrogen chemisorbed thereon, and for three-dimensional silicon, with a view to compare two charge-partitioning schemes, and the convergence of the results with respect to the order of the multipole expansions. It is shown that the inclusion of all terms to hexadecapole confines the error in the Coulomb contribution to the total energy for all the systems considered to within 0.001 a.u./atom, with the exactly treated zone reduced to a few neighbors, and that at this level the results are essentially independent of the particular charge-partitioning scheme adopted.
116 citations
TL;DR: In this paper, a simplified model to account for couplings to inelastic excitation and transfer reaction channels was proposed to estimate sub-barrier fusion cross sections for 40 Ar + 122 Sn, 58 Ni + 58 Ni and 58 Ni+64 Ni.
96 citations
TL;DR: It is shown that addition of cyclic AMP to disaggregated cells specifically prevents the destabilization of these mRNAs.
Abstract: The stability of mRNA is an important facet of the regulation of protein synthesis. In mammalian cells most mRNAs have long half-lives (5–15 hours) but a substantial fraction are much less stable1,2. There are few examples where the stability of a particular mRNA or class of mRNAs is specifically affected by environmental or developmental stimuli. Certain hormones cause specific stabilization of mRNAs species3 and preferential mRNA stability is important in the accumulation of globin and myosin mRNAs during the terminal stages of erythropoesis or myogenesis, respectively4–7. Disaggregation of Dictyostelium discoideum aggregates induces the specific destabilization of a large class of developmentally regulated mRNAs; thus, this system is an excellent one in which to determine how such controls are effected8–10. Here we show that addition of cyclic AMP to disaggregated cells specifically prevents the destabilization of these mRNAs.
94 citations
TL;DR: The sequence indicates that Retinol Binding Protein is synthesized as a single polypeptide chain precursor which is then matured to the secreted protein by removal of a leader peptide.
Abstract: We have isolated and sequenced a cDNA clone coding for human Retinol Binding Protein. The sequence indicates that Retinol Binding Protein is synthesized as a single polypeptide chain precursor which is then matured to the secreted protein by removal of a leader peptide. Southern and Northern blot analysis suggest that the gene is present in one or few copies per haploid genome and is transcribed in a single mRNA species.
92 citations
TL;DR: The results show that insulin receptor binding is diminished in Type 1 diabetes, perhaps as a consequence of higher peripheral blood insulin levels and that metformin can improve binding, and so reduce the amount of insulin needed to reach euglycaemia.
Abstract: The effect of metformin on Type 1 (insulin-dependent) diabetes has been assessed with the artificial pancreas. Fourteen Type 1 diabetic patients of normal body weight received in addition to their usual insulin therapy 850 mg metformin or placebo three times a day for 4–6 weeks. The sequence was placebo-metformin in eight patients and metformin-placebo in the other six. On the last day of metformin or placebo treatment, an artificial pancreas was used for about 36 h to assess insulin requirement. There was a 25.8% reduction in insulin requirement during metformin management despite slightly lower blood glucose levels (5.25±0.20 versus 5.98±0.18 mmol/l, P<0.01). Maximum reduction (about 50%) occurred 2 h after both lunch and dinner. There was no nocturnal effect. A marked decrease in specific insulin binding before metformin was found (0.56 + 0.27% to 107 monocytes versus 2.82±0.75 of control subjects) and significant increase after metformin (1.36±0.36%, p<0.05). There were no significant changes in blood lactate, total and HDL-cholesterol, triglycerides and C-peptide levels. These results show that insulin receptor binding is diminished in Type 1 diabetes, perhaps as a consequence of higher peripheral blood insulin levels and that metformin can improve binding, and so reduce the amount of insulin needed to reach euglycaemia. The insulin sparing effect is greatest after meals, and interference with intestinal absorption of sugars may also be important. It follows that metformin could be usefully administered to Type 1 diabetic patients with unimpaired liver and renal function to reduce their insulin requirement.
92 citations
TL;DR: Treatment of isolated hepatocytes from 3-methylcholanthrene induced rats with 1 mM paracetamol has been found to greatly decrease cellular reduced glutathione (GSH) content and to promote lipid peroxidation, evaluated as malonaldehyde (MDA) production and conjugated diene absorbance.
90 citations
TL;DR: It is proved that all and the only type schemes deducible for X can be obtained from the p.t.s. of X by suitable operations.
89 citations
TL;DR: In this paper, the authors studied the covariant bifurcation problems from the point of view of singularity theory and group theory, thus refining the work of Sattinger.
Abstract: One of the simplifications, used by Sattinger (1978), in studying the planar Benard problem is to assume that the solutions are doubly periodic with respect to the hexagonal lattice in the plane. Once one makes this assumption, the generic situation is that the kernel of the linearized Boussinesq equations (linearized about the pure conduction solution) is six-dimensional, the eigenfunctions being superpositions of plane waves along three directions at mutual angles of 120°. In this situation the Liapunov-Schmidt procedure leads to a reduced bifurcation problem of the form g ( x, λ ) = 0 where g: [R6 x R -» R6 is smooth. Here λ represents the Rayleigh number. Moreover, such a g must commute with the symmetry group of the hexagonal lattice. In the paper we study such covariant bifurcation problems from the point of view of singularity theory and group theory, thus refining the work of Sattinger (1978). In particular we are able to classify the simplest such bifurcation problems as well as all of their perturbations. We find that stable rolls and stable hexagons occur as possible solutions. In addition, we find a rich structure of non-stable equilibrium solutions including wavy rolls and false hexagons appearing in the unfoldings of even the simplest degenerate bifurcation problems.
TL;DR: It is shown that destruction of its ventromedial, dorsomedial and arcuate nuclei persistently abrogates NK activity in mice, and agents inducing NK-cell maturation or activation such as poly inosinic-polycytidylic acid (poly(I:C), interferon (IFN) and interleukin-2 (IL-2) restore NK activity, and normalize the number of LGL.
Abstract: Natural killer (NK) cells have an important role in non-adaptative resistance to tumours and their metastatic spread in vivo. Maturation of NK cells and the intensity of their activity are affected by many endogenous and external factors, as well as by regulatory cells. The possibility that some effects of the central nervous system on tumour resistance are mediated via NK activity has also been suggested. Destruction of the tuberoinfundibular region of the hypothalamus in rodents led to a significant increase in tumour growth. We show here that destruction of its ventromedial, dorsomedial and arcuate nuclei persistently abrogates NK activity in mice. By contrast, cortical lesion and operative stress depress it partially, and for a brief period only. Abrogation is the result of a block of NK lineage maturation, causing a severe decrease in the number of large granular lymphocytes (LGL), a lymphocyte population associated with NK activity. Macrophage, B- and T- lymphocyte functions, however, are not significantly affected. Agents inducing NK-cell maturation or activation such as polyinosinic-polycytidylic acid (poly(I:C], interferon (IFN) and interleukin-2 (IL-2) restore NK activity, and normalize the number of LGL.
TL;DR: Fractionation experiments suggest that this functional impairment in B‐CLL is not only due to the abnormal T‐cell subset distribution seen in the majority of cases, but point to a possible intrinsic defect within the Tμ cell population.
Abstract: The helper and suppressor capacity of T, T mu (T non gamma) and T gamma cells was assessed in a group of patients with B-cell chronic lymphocytic leukaemia (B-CLL) in a pokeweed mitogen (PWM) stimulated system. The enriched T-cells (E-rosette positive) from all B-CLL cases showed a reduced capacity to induce the differentiation of normal B-lymphocytes compared with normal T-cells (P less than 0.005). After enrichment of the T mu cells, the helper/inducer capacity was still significantly depressed compared with the same fraction from normal controls (P less than 0.01). On the other hand, enriched T gamma cells from B-CLL were effective in suppressing the differentiation of normal B-lymphocytes to a similar degree as normal T gamma cells. These findings are indicative of a deficient T-cell helper function in B-CLL, which appears to be unrelated to the clinical stage of the disease. The fractionation experiments suggest that this functional impairment is not only due to the abnormal T-cell subset distribution seen in the majority of cases, but point to a possible intrinsic defect within the T mu cell population.
TL;DR: In this paper, four kinds of divalent Cr ions are present at the surface of CO-reduced, low-loaded (0.5% by weight) chromia/silica samples, and all react with NO eventually yielding linear dinitrosyl species.
TL;DR: In this article, a sample of flares detected in 1980 with the Bent Crystal Spectrometer and the Hard X-Ray Burst Spectrometers on the Solar Maximum Mission satellite has been analyzed to study the upward motions of part of the soft X-ray emitting plasma.
Abstract: A sample of flares detected in 1980 with the Bent Crystal Spectrometer and the Hard X-Ray Burst Spectrometer on the Solar Maximum Mission satellite has been analysed to study the upward motions of part of the soft X-ray emitting plasma. These motions are inferred from the presence of secondary blue-shifted lines in the Ca XIX and Fe XXV spectral regions during the impulsive phase of disk flares. Limb flares do not show such blue-shifted lines indicating that the direction of the plasma motion is mainly radial and outward. The temporal association of these upward motions with the rise of the thermal phase and with the impulsive hard X-ray burst, as well as considerations of the plasma energetics, favour the interpretation of this phenomenon in terms of chromospheric evaporation. The two measureable parameters of the evaporating plasma, emission measure and velocity, depend on parameters related to the energy deposition and to the thermal phase. The evaporation velocity is found to be correlated with the spectral index of the hard X-ray flux and with the rise time of the thermal emission measure of the coronal plasma. The emission measure of the rising plasma is found to be correlated with the total energy deposited by the fast electrons in the chromosphere by collisions during the impulsive phase and with the maximum emission measure of the coronal plasma.
TL;DR: The pharmacokinetics of norfloxacin were studied in six healthy volunteers, and three patients each with moderate renal and hepatic damage, and results indicated slight and not statistically significant differences in comparison with healthy volunteers.
Abstract: The pharmacokinetics of norfloxacin were studied in six healthy volunteers, and three patients each with moderate renal and hepatic damage. A new specific and sensitive high performance liquid chromatography method was set up to measure plasma and urine concentrations of norfloxacin. The mean urinary concentrations after a single oral dose of 400 mg norfloxacin exceeded many times the MIC and MBC values of most of the bacterial strains responsible for urinary tract infections. Results in the patients with hepatic and renal damage indicated slight and not statistically significant differences in comparison with healthy volunteers.
TL;DR: The aim of the present study was to investigate the pathways of platelet-activating factor production and release from human monocytes and found that PAF release from monocytes could be dissociated from phagocytosis and from release of lysozyme.
Abstract: The aim of the present study was to investigate the pathways of platelet-activating factor (PAF) production and release from human monocytes. For this purpose, both phagocytic stimuli and stimuli indu
TL;DR: The sequence shows that haptoglobin is very likely synthesized as a single polypeptide chain which is then cleaved at an Arg residue to generate its two characteristic alpha and beta subunit.
Abstract: We have isolated and sequenced a cDNA clone coding for human haptoglobin. Our sequence shows that haptoglobin is very likely synthesized as a single polypeptide chain which is then cleaved at an Arg residue to generate its two characteristic alpha and beta subunit. Southern blot analysis suggests that there are at least two copies of the haptoglobin gene per haploid genome.
TL;DR: Several finite difference-schemes for approximating solutions of initial value problems associated with systems of linear hyperbolic differential equations and extensions to several space-like dimensions by splitting methods are considered.
TL;DR: In this paper, 19 substituted 2-phenylbenz-X-azoles, which are intermediates for the synthesis of dyes, were prepared from p-aminosalicylic acid (PAS).
TL;DR: Cell viability measurements show that halothane metabolism in both hypoxic and aerobic conditions can lead to cell death, and oxidative lipid damage could be a cause of cell damage, as judged by cell viability, additional to covalent binding.
TL;DR: In this paper, a distinction is made between expressive and instrumental scapegoats, defined as the product of a rational strategy adopted by one or more power holders to prevent the blame for an incident from reaching higher hierarchical levels.
Abstract: A preliminary distinction is made between expressive and instrumental scapegoats. The latter are defined as the product of a rational strategy adopted by one or more power holders to prevent the blame for an incident from reaching higher hierarchical levels. The basic assumption in this article is that symbolic blame-giving processes within complex organizations must satisfy certain requirements in order to be credible. They can, thus, be studied in terms of purposive organizational behaviour and not solely as the emotional outcome of collective psychological dynamics. The analysis of five cases of scapegoating in the French political-administrative systems leads to the construction of a typology. The analysis of a number of Italian cases, however, shows that the French typology requires expansion in order to allow comparison with Italy. Possible means of achieving this comparison are suggested in the conclusion.
TL;DR: In this paper, it was shown that the compactified vacuum solution of D = 11 supergravity has an Osp ( 4 8 ) symmetry, and that the solution describes the rigid superspace Osp(4 8 )/ SO (1,3) ⊗ SO (7).
TL;DR: The results are consistent with the interpretation that the brush border of proximal tubules of human kidney activates the C system via the alternative pathway and it is suggested that this activation may occur in vivo in patients with a non-selective proteinuria.
Abstract: The aim of this investigation was to study complement fixation by normal human kidney tissue. C fixation was assessed on acetone-fixed sections of frozen human kidney. In addition, C consumption following incubation of normal fresh human serum with tubular or glomerular fractions of human kidney was measured. The results are consistent with the interpretation that the brush border of proximal tubules of human kidney activates the C system via the alternative pathway. It is suggested that this activation may occur in vivo in patients with a non-selective proteinuria.
TL;DR: The chelating material described in this article has iminodiacetate functional groups chemically bonded to commercial cellulose filters in order to preconcentrate trace metals in aqueous samples.
TL;DR: In 35 patients with B-cell chronic lymphocytic leukemia (B-CLL), T lymphocytes were characterized by their ability to react with OKT-4 andOKT-8 monoclonal antibodies and the expression of Fc receptors was compared, providing further evidence of the T-cell abnormality in this disease.
TL;DR: In this article, a tetrahedral tri-hydridic structure of the hexametallic NiOsmium complex was characterized by spectroscopic techniques, and a preliminary investigation of homogeneous hydrogenation of these substrates was reported.
TL;DR: The distribution of MND was uneven in the Province suggesting a proportional relationship to the distribution of population density, and Amyotrophic lateral sclerosis was found to be 4 times more frequent than progressive muscular atrophy.
Abstract: The incidence and prevalence of motor neuron disease (MND) in the Province of Turin, North-West Italy, were investigated for the period 1971-1980. The crude incidence rate of MND was 0.67/100,000/year. The annual incidence rate, age and sex adjusted to the Italian population in 1971 was 0.69 cases per 100,000 inhabitants, 0.94 for men and 0.45 for women, with a male to female incidence ratio of 2.09:1. The prevalence of MND was 2.62/100,000, 3.57 for males and 1.71 for females. The mean age at the time of diagnosis was 55.6 years. Annual incidence rates increased with advancing age. Amyotrophic lateral sclerosis was found to be 4 times more frequent than progressive muscular atrophy (0.53/100,000/year v. 0.14/100,000/year). The distribution of MND was uneven in the Province suggesting a proportional relationship to the distribution of population density. Possible explanations of this finding are discussed.
TL;DR: In the vacuum solution proposed by Englert, in which the three-index photon of d = 11 supergravity plays the role of a non-vanishing torsion which parallelizes the seven-sphere, all supersymmetries are broken as discussed by the authors.
TL;DR: The supernatant of the highly anaplastic Yoshida hepatoma is able to decrease the peroxidation rate in normal liver microsomes, which seems to be related to their degree of deviation, low deviation tumours displaying higher peroxidative ability.
Abstract: Lipid peroxidation rate in four different hepatomas is quite different and seems to be related to their degree of deviation, low deviation tumours displaying higher peroxidative ability. Moreover, the supernatant of the highly anaplastic Yoshida hepatoma is able to decrease the peroxidation rate in normal liver microsomes. This antioxidant ability is not dependent upon an increased level of glutathione. The concentration of reduced glutathione (GSH) declines strongly during incubation in conditions favouring lipid peroxidation. Unlike normal liver homogenates, this decline of GSH in hepatomas is not due to the transformation of GSH into oxidized glutathione (GSSG) but mostly to the increased activity of the gamma-glutamyl-transpeptidase pathway.