Showing papers by "University of Bologna published in 1979"

The classical field limit of scattering theory for non-relativistic many-boson systems. II

Abstract: We study the classical field limit of non relativistic many-boson theories in space dimensionn≧3, extending the results of a previous paper to more singular interactions. We prove the expected results: when ħ tends to zero, the quantum theory tends in a suitable sense to the corresponding classical field theory, and the quantum fluctuations are governed by the equation obtained by linearizing the quantum evolution equation around the classical solution. These results hold uniformly in time and therefore apply to scattering theory. The interactions considered here are so singular as to require a change of domain in order to define the generator of the evolution of the fluctuations, but sufficiently regular so that no energy renormalization is needed.

Non-inactivation of an x-chromosome locus in man

Abstract: Cloned fibroblasts from women heterozygous for X-linked ichthyosis (steroid sulfatase deficiency) were examined to see whether or not this locus is subject to X-inactivation. Of 103 clones examined, all had normal levels of steroid sulfatase activity. Two of the women studied were also heterozygous for glucose-6-phosphate dehydrogenase deficiency. This allowed the demonstration that both X chromosomes were represented as the active X in various clones and that selection did not account for these findings. Thus, the steroid sulfatase locus, like the Xga locus to which it is linked, appears to escape X-inactivation in man.

Differentiation of myeloid leukaemic cells: new possibilities for therapy.

Abstract: The present status of therapy of acute myeloid leukaemia (AML) does not give much hope to chemotherapists and clinical haematologists (Gunz & Vincent, 1977). However, an interesting point was raised by Sachs (1978) in his recent annotation in this Journal. He suggested that a number of substances, including several cytotoxic drugs, could be exploited for their potential of inducing differentiation of myeloid leukaemic cells. One of these drugs is Arabinosyl Cytosine (ARA-C); its main action is on DNA replication (cell proliferation), and it can also affect the processes leading to cell maturation (Lotem & Sachs, 1974; Krystosek & Sachs, 1976). ARA-C is reputed to lead AML into complete remission through the killing of a substantial number of leukaemic cells. Such a cell killing effect of ARA-C a t the doses employed in AML is unquestionable, but the possibility also exists that ARA-C could also act by slowing down cell proliferation, so as to allow the cells that escape death to express their residual potential for differentiation and maturation. To test this possibility, we have scored the proportion of granulated versus non-granulated leukaemic blast cells before and immediately after a 24 h continuous infusion of ARA-C (total dose 10 mg/kg), in eight consecutive patients with AML, prior to any other therapy. The proportion of granulated blast cells became significantly higher after ARA-C in five of eight cases (mean value 31.6% before ARA-C, and 60.2% after the drug). In some patients the proportion of granulated cells before therapy was so low so as to make the diagnosis of AML difficult, but most of these 'undifferentiated' blast cells became clearly granulated after ARA-C. This was accompanied by a marked or total inhibition of cell proliferation, as shown by a drop of the mitotic index towards zero. The possibility that ARA-C can allow cell maturation through inhibition of cell proliferation is also suggested by the response to the drug of a patient with refractory anaemia with excess marrow myeloblasts. This is one of the haemopoietic dysplasias or preleukaemic disorders whose study may provide important information on human leukaemia (Dreyfus, 1976; Ricci et a l , 1978). This patient (Fig 1) was treated by red cell transfusions for 6 months. During that time he remained severely neutropenic (polymorphonuclears < 0.5 x 109/1) and thrombocytopenic (platelet count <50 x 109/l). At the sixth month he was given ARA-C in a very small dose (0.7 mg/kg/d i.v., for 7 consecutive days). 15-30 d after this course of ARA-C, platelet and polymorphonuclear (PMN) count became normal, and remained much higher than their pre-ARA-C levels for at least 6 months. During that time, the Hb level remained normal without any blood transfusion. Marrow was checked several times before and after ARA-C. Before ARA-C, the proportion of marrow myeloblasts ranged between 20% and 30%, and granulopoiesis was very defective, with very small numbers of myelocytes and PMN. Dyserythropoiesis was severe, and megakaryocytes were rare. After ARA-C, the proportion of marrow myeloblasts dropped to 5-lo%, with normal amount of myelocytes and PMN. Dyserythropoiesis became milder, and megakaryocytes were more frequent. Thus, the marrow picture remained abnormal, but cells matured better. Six months after ARA-C, the

Hemisphere‐dependent Cognitive Performances in Epileptic Patients

Abstract: Summary: Short-term memory (STM), long-term memory (LTM), and recency judgment were investigated in 75 right-handed nonaphasic patients without visual deficits who had epileptic foci localized in one of four different regions of the brain: right temporal lobe, left temporal lobe, right frontal lobe, and left frontal lobe. The results led to the following conclusions: (1) left temporal lesions yielded comparatively greater impairment for the verbal LTM task, whereas right temporal lesions were more disruptive for the spatial LTM task; (2) no significant differences between left- and right-brain-damaged patients in STM tasks were obtained; (3) left frontal lesions yielded deficits in a recency task in accordance with hemispheric specialization; (4) only prolonged epileptic syndroipes impaired neuropsychological performance in those tests; (5) comparisons between male and female patients and between those with and without clear evidence of a structural lesion did not reach statistical significance. RESUME La memoire des faits recents, celle des faits anciens ainsi que le “recency judgement” ont eteetudies chez 75 malades droitiers ne presentant ni aphasie, ni trouble de la vision mais porteurs de foyers epileptiques localises dans L'un des quatre territoires suivants: lobe temporal droit, lobe temporal gauche, lobe frontal droit et lobe frontal gauche. Les resultats obtenus permettent de conclure: 1o que les lesions du lobe temporal gauche entrainent des troubles compar-ativement plus importants pour les tests verbaux lies a la memoire des faits anciens alors que les lesions du lobe temporal droit pertubaient davantage les donn6es spatiales de la memoire des faits anciens; 2o qu'il n'a pas ete note de difference significative entre les sujets porteurs de lesions hemispheriques droites ou gauches en ce qui concerae la memoire des faits recents; 3o que les lesions frontales gauches entrainaient une diminution dans la “recency task” en accord avec la specialisation hemispherique; 4o que seuls les syndromes epileptiques prolonges alterent les perfomances neuropsychologiques etudiees par ces tests; 5o qu'il n'existe pas de difference statistiquement significative entre les sexes ni entre les sujets porteurs D'une lesion organique evidente et les autres. Das Kurzzeitgedachnis (STM), Langzeitgedachnis (LTM) und das akute Urteilsvermogen wurden bei 75 rechtshandigen nicht aphasischen Patienten ohne Sehdefekte untersucht, die epileptische Foci in einer der 4 verschiedenen Regionen des Gehirns hatten: Rechter Temporallappen, linker Temporallappen, rechter Frontallappen, linker Frontallappen. Die Ergebnisse erlauben folgende Schlusse: 1. Lasionen der linken Temporalregion fuhren zu verhaltnismasig groserer Beeintrachtigung fur Aufgaben des verbalen LTM, wahrend rechte Temporallasionen starker Aufgaben des raumlichen LTM beeintrachtigen. 2. Keine signifikanten Unterschiede bestehen zwischen links und rechts hirngeschadigten Patienten bei Aufgaben, die das STM betreffen. 3. Lasionen links frontal fuhren zu Beeintrachtigungen von Aufgaben des Frisch gedachtnisses entsprechend der hemispharis-chen Spezialisierung. 4. Nur sehr lange anhaltende epileptische Entladungen beeintrachtigten neuro-psychologische Ergebnisse in den gepruften Tests. 5. Signifikante Unterschiede zwischen mannlichen und weiblichen Patienten und zwischen denen mit und ohne Ware Hinweise auf strukturelle Lasionen ergeben sich nicht. ZUSAMMENFASSUNG

Inclusive interactions of high-energy neutrinos and antineutrinos in iron

Abstract: We present results on charged current inclusive neutrino and antineutrino scattering in the neutrino energy range 30–200 GeV. The results include a) total cross-sections; b)y distributions; c) structure functions; and d) scaling violations observed in the structure functions. The results, as well as their comparison with the results of electron and muon inclusive scattering, are in agreement with the expectations of the quark parton model and QCD.

Sequences of infinite bifurcations and turbulence in a five-mode truncation of the Navier-Stokes equations

Abstract: Two infinite sequences of orbits leading to turbulence in a five-mode truncation of the Navier-Stokes equations for a 2-dimensional incompressible fluid on a torus are studied in detail. Their compatibility with Feigenbaum's theory of universality in certain infinite sequences of bifurcations is verified and some considerations on their asymptotic behavior are inferred. An analysis of the Poincare map is performed, showing how the turbulent behavior is approached gradually when, with increasing Reynolds number, no stable fixed point or periodic orbit is present and all the unstable ones become more and more unstable, in close analogy with the Lorenz model.

Insulin and glucagon levels in liver cirrhosis. Relationship with plasma amino acid imbalance of chronic hepatic encephalopathy.

Abstract: Alterations in insulin and glucagon levels might account for the plasma amino acid imbalance of cirrhotics. In order to verify this hypothesis we evaluated basal insulin, glucagon, branched-chain amino acids, aromatic amino acids, and free tryptophan in 13 controls and 37 cirrhotics divided on the basis of their mental state; in 4 patients the hormonal and amino acid patterns were sequentially studied during various stages of encephalopathy. Glucagon is high in cirrhotics and progressively increases with the worsening of the mental state. Free tryptophan and aromatic amino acids show a similar behavior and significantly correlate with glucagon levels (r = 0.67 and r = 0.81, respectively). On the other hand insulin levels, which are high in cirrhotics without encephalopathy, fall in the presence of deep coma. Insulin did not correlate with any of the plasma amino acids considered. Our data suggest that the catabolic state associated with increased glucagon levels may account for some of the alterations in the plasma amino acid profiles of cirrhotics. Portal-systemic shunting does not seem to be the common cause of both hyperglucagonemia and hyperaminoacidemia. Decreased branched-chain amino acid levels may be related to factors different from those involved in the alterations of carbohydrate homeostasis.

Intralymphocytic sodium in hypertensive patients: a significant correlation.

Abstract: 1. Intralymphocytic sodium concentration was measured in 50 patients with essential stable hypertension, 44 patients with labile hypertension and 40 subjects with normal blood pressure. 2. Intralymphocytic sodium concentration in normotensive subjects was significantly lower than in the other two groups. 3. The concentration was significantly correlated with mean blood pressure in the group as a whole and in the groups with stable and with labile hypertension. No correlation was found in normal subjects.

Excited state electron-transfer reactions of transition metal complexes

Abstract: The properties of excited states of transition metal complexes are briefly reviewed. The outer-sphere electron transfer reactions of the excited states of complexes containing 2,2'-bipyridine or 1,10-phenanthroline ligands are discussed in detail, with particular reference to electron vs energy transfer quenching and conversion of light into chemical energy. The kinetic aspects of outer–sphere electron transfer reactions involving excited states are examined with particular reference to the so-called “Marcus inverted behavior” which is not observed in most of the systems studied. The extension of the kinetic formalism used for electron transfer reactions to energy transfer processes yields a unified view of “classical” and “ non-classical” energy transfer behavior.

Best coapproximation in normed linear spaces

Abstract: We consider, in normed linear spaces, a kind of “approximation” by elements of linear subspaces, introduced byC. Franchetti andM. Furi [5], which we call best coapproximation. We obtain some results on characterization and existence of elements of best coapproximation in arbitrary normed linear spaces and in spaces of continuous functions. We give some characterizations of strict convexity in terms of best coapproximation and we study some properties of the setvalued operators of best coapproximation.

The inhibition of susceptible and hypersensitive reactions by protein-lipopolysaccharide complexes from phytopathogenic pseudomonads: relationship to polysaccharide antigenic determinants

Abstract: Protein-lipopolysaccharide (pr-LPS) complexes were purified from a virulent strain of Pseudomonas tabaci (NCPPB 1427) and two incompatible strains ( P. aptata NCPPB 2664 and P. lachrymans NCPPB 1436). They all contained two major polypeptides with mol. wts of 20 000 and 40 000. Slide agglutination tests with O- or pr-LPS-antisera produced against antigens from P. aptata NCPPB 2664 showed that the surface antigens of P. aptata had common determinants with P. tabaci NCPPB 1427, but not with P. lachrymans NCPPB 1436. Precipitin ring tests of heat-stable antigens (121 °C) in the presence of pr-LPS antiserum indicated that most determinants were carried by lipopolysaccharides. Pr-LPS complexes from the three strains, pre-injected into tobacco leaves, prevented hypersensitive confluent necrosis evoked by seven incompatible pseudomonads, and delayed or inhibited the development of the susceptible reaction induced by five compatible strains. These effects were unrelated to the degree of virulence of compatible strains and to the type of surface antigenic determinants of the whole bacterium, as recognized by the rabbit immune system. This suggests a common mechanism of interaction in the protected tissue, causing plant tolerance to various degrees towards different strains. Pr-LPS complexes of P. tabaci NCPPB 1427 were most effective in inducing protection, consistent with the possibility that compatible strains may produce surface substances having higher tolerance-inducing activity.

Reflection and transmission of discontinuity waves through a shock wave. General theory including also the case of characteristic shocks

Abstract: An incident wave creates a discontinuity in the acceleration of the shock front. The amplitudes of the reflected and transmitted waves are also determined. Special attention is given to the case of the weak shocks and the characteristic shocks.

Two forms of NADP-dependent malic enzyme in expanding maize leaves.

Abstract: Etiolated maize leaves (Zea mays L.) contain a major isozyme of NADP-dependent malic enzyme (L-malate dehydrogenase, decarboxylating, EC 1.1.1.40) having an isoelectric point of 5.28±0.03, a Km (L-malate) 0.3–0.6 mM at pH 7.45; a broad pH optimum around pH 6.9 under the conditions of assay; a molecular weight of 280,000 (sometimes accompanied by a minor component of 150,000); and an NAD-dependent activity about 1/50 the NADP-dependent activity. This isozyme, resembling the NADP-malic enzyme of vertebrates, is labeled type 1. The dominant isozyme of young green leaves (type 2) has, however, a pI 4.90±0.03, a Km (L-malate) 0.10–0.15 mM, a pH optimum of 8, and a molecular weight of 280,000. It is also more stable and exhibits an appreciable NAD-dependent activity (1/5–1/7 the NADP activity). Both isozymes show linear kinetics, dependence on Mn or Mg ions, similar Km (NADP+), and the typical increase of Km for L-malate with increasing pH values. Type 1 isozyme of maize is assumed to be cytosolic. Type 2 corresponds in each property to the chloroplast enzyme of bundle-sheath cells. It is present at a low level in etiolated leaves and develops to a high specific activity (up to 100 nmol min-1 mg protein-1 by 150 h illumination) during photosynthetic differentiation, replacing the type 1 form.

Effect of ursodeoxycholic acid administration on biliary lipid composition and bile acid kinetics in cholesterol gallstone patients

Abstract: The effect of ursodeoxycholic acid (UDCA) on bile lipid composition and bile acid kinetics was evaluated in seven cholesterol gallstone patients following one month of UDCA administration (12 mg/kg/day). UDCA administration induces a significant reduction in the cholesterol saturation index (SI). After UDCA treatment, UDCA becomes the predominant biliary bile acid while chenodeoxycholic, cholic, and deoxycholic acid are significantly reduced. UDCA pool significantly increases, and chenodeoxycholic, cholic, and total bile acid pools significantly decrease. The reduction in bile lithogenicity during UDCA administration suggests that UDCA may be useful for cholesterol gallstone treatment in man.