Showing papers by "University of Udine published in 1993"

PCR-amplified microsatellites as markers in plant genetics.

Abstract: In order to assess the feasibility of using microsatellites as markers in plant genetics, a survey of published DNA sequence data for presence, abundance and ubiquity in higher plants of all types of dinucleotide and trinucleotide repeats with a minimum number of 10 and 7 units, respectively, was conducted. This search revealed that such microsatellites are frequent and widely distributed; they were uncovered in 34 species, with a frequency of one every 50 kb. AT repeats were by far the most frequently observed class of dinucleotide microsatellites, whereas AC/TG repeats, which are common in animals, were observed only once. TAT repeats prevailed among trinucleotides. Polymerase chain reaction amplification of (AT)n and (TAT)n microsatellites in soybean (Glycine max (L.) Merr.) revealed that they are highly polymorphic, as a consequence of length variation, somatically stable and inherited in a co-dominant Mendelian manner. The abundance and amount of information derived from such markers, together with the ease by which they can be identified, make them ideal markers for plant genetic linkage and physical mapping, population studies and varietal identification.

Coagulation activation in diabetes mellitus: the role of hyperglycaemia and therapeutic prospects.

Abstract: Numerous studies have shown that coagulation abnormalities occur in the course of diabetes mellitus, resulting in a state of thrombophilia. These observations are supported by epidemiological studies which demonstrate that thromboembolic events are more likely to occur in diabetic patients. The coagulation abnormalities observed in diabetic patients seem to be caused by the hyperglycaemia, which also constitutes the distinguishing feature of this disease. These data are also supported by in vitro studies which demonstrate how glucose can directly determine alterations in the coagulation system. The abnormalities observed involve all stages of coagulation, affecting both thrombus formation and its inhibition, fibrinolysis, platelet and endothelial function. The final result is an imbalance between thrombus formation and dissolution, favouring the former. Hyperglycaemia probably determines the onset of these abnormalities through three mechanisms which are, respectively, non-enzymatic glycation, the development of increased oxidative stress and a decrease in the levels of heparan sulphate. The first seems to affect the functionality of key molecules of coagulation in a negative sense. Oxidative stress constitutes an important pro-thrombotic stimulus, while the decrease in heparan sulphate determines a reduction in antithrombotic defenses. Good metabolic control could play a key role in controlling the coagulation irregularities in diabetes. However, considering the difficulties in achieving such an objective, it is possible that the use of drugs may represent a valid alternative. In fact, several drugs exist which are of potential interest. It is, however, necessary to perform long-term studies which demonstrate unequivocably that by controlling the coagulation abnormalities in diabetic patients, prolongation of life is possible.

Metformin for obese, insulin-treated diabetic patients: improvement in glycaemic control and reduction of metabolic risk factors

Abstract: The efficacy and safety of metformin in the treatment of obese, non-insulin-dependent, diabetic subjects poorly controlled by insulin after secondary failure to respond to sulphonylureas has been investigated. Fifty insulin-treated, obese diabetics participated in this prospective, randomised double-blind six-month trial. After a four-week run-in period, during which all patients were given placebo (single-blind), patients were randomly assigned to continue to receive placebo or to active treatment with metformin. At six months, there was a relevant and significant improvement in glycaemic control in diabetics receiving the combined insulin-metformin treatment (decrease in glucose −4.1 mmol·l−1; glycosylated haemoglobin A1 decrease −1.84%). No significant changes were seen in diabetics receiving insulin and placebo. There was a significant decrease in blood lipids (trygliceride and cholesterol), an increase in HDL-cholesterol and a reduction in blood pressure in diabetics taking metformin. These postive findings were most marked in the 14 diabetics who experienced a good response to metformin (glucose profile 10 mmol·l−1). The fasting insulin level was significantly lower after six months of combined insulin-metformin treatment as shown by a 25% reduction in the daily dose of insulin (−21.6 U/day). Metformin was well tolerated by all diabetics. Combining metforming with insulin in obese, insulin-treated and poorly controlled diabetics may represent a safe strategy to achieve better glycaemic control with a reduction in certain metabolic risk factors associated with the increased incidence of cardiovascular disease in diabetes mellitus.

Renal tubular dysfunction in chronic alcohol abuse : effects of abstinence

Abstract: Background Alcohol abuse may be accompanied by a variety of disorders of electrolyte and acid-base metabolism. The role of the kidney in the pathogenesis of these disturbances is obscure. We sought to evaluate the alcohol-induced abnormalities of renal function and improvement during abstinence and to assess the relation between renal dysfunction and electrolyte and acid-base disorders. Methods We measured biochemical constituents of blood and renal function before and after four weeks of abstinence in 61 patients with chronic alcoholism who had little or no liver disease. Results On admission, 18 patients (30 percent) had hypophosphatemia and hypomagnesemia, 13 patients (21 percent) had hypocalcemia, and 8 patients (13 percent) had hypokalemia. Twenty-two patients (36 percent) had a variety of simple and mixed acid-base disorders. Twenty of these patients had metabolic acidosis, and among them, 80 percent had alcoholic acidosis. A wide range of defects in renal tubular function, with normal glomerular filtration rate, were detected in these patients. The defects included decreases in the threshold and maximal reabsorptive ability for glucose (38 percent of patients) and in the renal threshold for phosphate excretion (36 percent); increases in the fractional excretion of beta 2-microglobulin (38 percent), uric acid (12 percent), calcium (23 percent), and magnesium (21 percent); and aminoaciduria (38 percent). Seventeen patients (28 percent) had a defect in tubular acidification, and five an impairment in urinary concentrating ability. Urinary excretion of N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase were increased in 41 and 34 percent of patients, respectively. The abnormalities of blood chemistry and renal tubular function disappeared after four weeks of abstinence. Conclusions Transient defects in renal tubular function are common in patients with chronic alcoholism and may contribute to their abnormalities of serum electrolyte and blood acid-base profiles.

Volatile metabolites produced in wine by mixed and sequential cultures of Hanseniaspora guilliermondii or Kloeckera apiculata and Saccharomyces cerevisiae

Abstract: Secondary products in wines obtained by pure, mixed and sequential cultures of Saccharomyces cerevisiae, Hanseniaspora guilliermondii or Kloeckera apiculata were studied. Consistent differences in the composition were determined in wines fermented by sequential cultures. When S. cerevisiae was added to musts partially fermented by apiculate yeasts, its metabolism was significantly affected. In particular it synthesized high amounts of n-propanol and metabolized high quantities of acetoin, produced by apiculate yeasts

‘Mirror pain’ in the formalin test: behavioral and 2-deoxyglucose studies

Abstract: Subcutaneous injection of a dilute formaldehyde solution (5 or 10%) into a hind paw induced, in the majority of rats, the appearance of ‘mirror pain’: licking the contralateral untreated hind paw 10–60 min after injection. Contralateral licking activity was much less frequent than the ipsilaterally directed one, but the overall intensities of the two responses were positively correlated. Qualitatively, the two behaviours were similar. Functional activity levels of the lumbar spinal cord, as revealed by the 2-deoxyglucose (2-DG) technique, were increased bilaterally over the first hour after unilateral hind limb formalin injection in unanesthetized, freely moving rats. The enhancement of the [14C]2-DG uptake could be detected both in dorsal and ventral horns, as well as in the gray matter surrounding the central canal, and the anterolateral and dorsolateral funiculi. These metabolic changes may reflect an enhancement of the functional activity of both interneuronal pools and units projecting to supraspinal centers, giving rise to a referred contralateral pain.

Response of leguminosae to cadmium exposure

Abstract: Bush bean and pea plants grown in a sandy substrate and treated daily with nutrient solutions containing either 50 and 125 pM cadmium (Cd), added as cadmium nitrate [Cd(NO3)2], were analyzed for dry matter production, total Cd content, and extractable Cd. Cadmium depressed dry matter production of both plant species. Bush bean plants accumulated larger amounts of Cd in tissues and displayed lower Cd tolerance than pea plants. The high accumulation of Cd in roots of bush bean does not seem to prevent Cd translocation. Pea plants show a higher exclusion capacity at the root level, suggesting that membrane selectivity rather than apoplastic compartmentation may act as a defence mechanism against Cd toxicity. Gel‐permeation chromatography and voltammetric analyses showed that part of water‐soluble Cd extracted from tissues of pea and bush bean was as free metal ion (Cd2+). In addition, Cd into the nutrient solution induced progressively the synthesis of water‐soluble proteins at low molecular weigth ...

Low molecular weight humic substances stimulate H+-ATPase activity of plasma membrane vesicles isolated from oat (Avena sativa L.) roots

Abstract: The effect of 5 KDa (high molecular weight, HMW) humic fractions on transport activities of isolated plasma membrane vesicles was studied. The K+-stimulated component of the ATP-hydrolyzing activity was considerably increased by LMW humic substances at concentrations ranging from 0.075 mg org CL-1 to 1 mg org CL-1. The stimulation was still evident when the detergent Brij-35 was added in the assay mixture, indicating a direct effect of LMW humic substances on plasma membrane ATPase activity. The LMW humic fraction stimulated ATP-dependent intravesicular H+-accumulation with a pattern similar to that recorded for ATP hydrolysis. LMW humic substances induced also an increase in passive membrane permeability to protons, as revealed by following the dissipation of an artificially imposed pH gradient. Membrane permeability to anions, as measured by the anion-dependent active proton accumulation was affected by LMW humic substances. In the presence of NO3 - these molecules clearly enhanced proton transport, while Cl--dependent activity was almost unaffected, thus suggesting a specific action of LMW humic fraction on transmembrane NO3 - fluxes. On the other hand, HMW humic substances decreased the passive permeability to protons and reduced the anion-dependent intravesicular H+-accumulation. The results suggest that the stimulatory effect of soil humic substances on plant nutrition and growth might be, at least in part, explained on the basis of both direct action of LMW humic molecules on plasma membrane H+-ATPase and specific modification of cell membrane permeability.

Designing a high energy ball-mill for synthesis of nanophase materials in large quantities

Abstract: Nanophase materials can be synthesized by high energy milling. However, processing of large quantities finds a limitation in the devices available commercially, which are usually designed mainly for comminution and for laboratory-scale operations. We propose the design of a high energy, high capacity ball-mill which can be easily scaled up. An experimental device capable of processing up to about 250 g of powders with about 5 kg of balls has been realized. Impact velocities of about 3.5 m s −1 has been measured with operating frequencies of 17 Hz. The synthesis of nanophase iron carbides (assumed as a test system) is shown to be feasible with the new mill, with kinetics comparable with the best obtained in a Spex mill.

Kiwifruit pollination: An unbiased estimate of wind and bee contribution

Abstract: The role of wind and bees in kiwifruit (Actinidia deliciosa (A. Chev.) C.F. Liang et A.R. Ferguson) pollination was investigated using large cages enclosing 80 mature vines and assembled so as to prevent insects entering without reducing wind flow within the cages. Monitoring wind speed within the cage and in the open orchard showed that the cages were suitable for such experimentation. Cages without hives, cages with hives, open pollination with hives, and hand pollination were compared during 1990 and 1991. Wind pollination led to an appreciable fruit set (81 and 98% in the first and second year respectively) but fruit weight was low, averaging 61 and 66 g. The use of hives resulted in 98–100% fruit set, but fruit size did not improve significantly, remaining far below that achieved by hand pollination (66 g versus 108 g, the first year; 78 g versus 119 g, the second year). The short flowering period, the frequent adverse weather conditions, and the unpredictable foraging efficiency of bee colo...

A lambda calculus of objects and method specialization

Abstract: An untyped lambda calculus, extended with object primitives that reflect the capabilities of so-called delegation-based object-oriented languages, is presented. A type inference system allows static detection of errors, such as message not understood, while at the same time allowing the type of an inherited method to be specialized to the type of the inheriting object. Type soundness, in the form of a subject-reduction theorem, is proved, and examples illustrating the expressiveness of the pure calculus are presented. >

Pore-forming and haemolytic properties of the Gardnerella vaginalis cytolysin.

Abstract: The pleomorphic bacterium Gardnerella vaginalis releases in the culture broth a haemolytic exotoxin (Gvh) which is probably a virulence determinant of this unique bacterium, implicated in gynaecological and urological disorders. This 59 kDa cytolysin was purified to homogeneity in just one chromatographic step directly from the culture supernatant, a final specific activity up to 1.9 x 10(6) HU mg-1 being obtained. The toxin-induced lesion on human erythrocytes results from the formation of a pore whose radius is approximately 2.4 nm. The damage is inhibited by osmotic protectants and shows a sigmoidal dose-response profile suggesting an aggregation process of haemolysin molecules on the target membrane to create the functional lesion. The extent and the kinetics of haemolysis are strongly dependent on temperature and an activation energy of 64.0 kJ mol-1 has been derived. Lipid membranes can be very efficient inhibitors of Gvh-haemolysis, being able to bind the toxin quite avidly. The inhibitory effect requires the presence of cholesterol and it is stronger when cholesterol is mixed with negatively charged phospholipids rather than with zwitterionic phospholipids, suggesting that a negative surface potential increases the affinity of the toxin for the lipid bilayer. The functional properties of Gvh have been compared with those of Clostridium perfringens thetatoxin (PFO) and Escherichia coli haemolysin (HlyA), which are representative of widespread haemolysins produced by Gram-positive and Gram-negative bacteria, respectively. The toxin shares several features with the family of the so-called 'sulphydryl-activated' cytolysins produced by Gram-positive bacteria, although Gvh does not truly belong to this family, being deactivated by beta-mercaptoethanol and being antigenically distinct from them. We report here for the first time the detection in the vaginal fluid of infected women of a specific IgA response against the toxin.

Linear programming approach to the control of discrete-time periodic systems with uncertain inputs

Abstract: The problem is considered of finding a control strategy for a linear discrete-time periodic system with state and control bounds in the presence of unknown disturbances that are only known to belong to a given compact set. This kind of problem arises in practice in resource distribution systems where the demand has typically a periodic behavior, but cannot be estimated a priori without an uncertainty margin. An infinite-horizon keeping problem is formulated, which consists in confining the state within its constraint set using the allowable control, whatever the allowed disturbances may be. To face this problem, the concepts of periodically invariant set and sequence are introduced. They are used to formulate a solution strategy that solves the keeping problem. For the case of polyhedral state, control, and disturbance constraints, a computationally feasible procedure is proposed. In particular, it is shown that periodically invariant sequences may be computed off-line, and then they may be used to synthesize on-line a control strategy. Finally, an optimization criterion for the control law is discussed.

Synthesis of Osmotically Active Substances in Winter Wheat Leaves as Related to Drought Resistance of Different Genotypes)

Abstract: Water stress increased mono-saccharides and decreased di-saccharides concentration in four field grown genotypes, regardless of their different drought susceptibility. Sandy, a USA genotype known for giving satisfying yields in droughty environments, outstood the other cultivars in terms of betaine and proline concentration in leaf tissues; these aminoacids are therefore considered responsible for the most negative Ψs perceived in this cultivar. PV-curve technique revealed for Tullio, the drought susceptible Italian genotype, an osmotic adjustment of –0.63 MPa, four times greater than in Pandas, though this drought resistant cultivar showed a similar content in osmotically active substances; the authors therefore hypothesize an alternative mechanism in the response to water shortage in Tullio. Zusammenfassung Synthese osmotisch aktiver Substanzen bei Winterweizenblattern in Beziehung zur Durreresistenz unterschiedlicher Genotypen Durch Wasserstres wurden bei vier im Feld angebauten Genotypen die Konzentrationen der Mono-Saccharide erhoht und die der Di-Saccharide erniedrigt; dies trat unabhangig von der Durreempfindlichkeit der Genotypen auf. Sandy, ein USA-Genotyp, der fur befriedigende Ertrage unter Durrebedingungen bekannt ist, ubertraf die anderen Kukivare im Hinblick auf Betain- und Prolin-Konzentrationen in den Blattgeweben. Diese Aminosauren werden daher als verantwortlich fur die meist negativen ψs, die in den Kultivaren gefunden werden, verantwortlich gemacht. PV-curve-Technik zeigte fur Tullio, den durreempfindlichen italienischen Genotyp, eine osmotische Anpassung von –0,63 MPa, viermal groser als bei Pandas, obwohl dieser durreresistente Kultivar einen vergleichbaren Gehalt in osmotisch aktiven Substanzen aufwies. Die Verfasser gehen daher davon aus, das ein alternativer Mechanismus in der Reaktion auf Wassermangel bei Tullio wirksam wird.

A Comparative Analysis of the Sensitivity of Multidrug Resistant (MDR) and Non-MDR Cells to Different Anthracycline Derivatives

Abstract: Because of the fact that tumor cell sensitivity to cytotoxic agents may play a major role in cancer treatment, and several anthracyclines are widely used for first-line treatment of leukemia, lymphoma and other tumors, and since the overexpression of the mdr-1 gene-coded 170 Kd glycoprotein (P170) decreases cell sensitivity to anthracyclines, we investigated the relationship between P170 overexpression and the cytotoxicity of two classic anthracyclines (Daunorubicin or DNR and Doxorubicin or DX) and two lipophilic anthracycline derivatives (Idarubicin or IDA and Iododoxorubicin or IDX). For these purposes, we used multidrug resistant (MDR) and non-MDR tumor and leukemia cell lines and the MTT-microcultured tetrazolium colorimetric assay. We showed that mdr-1 gene overexpression was strongly associated with the development of a high level of resistance to DNR and DX, but not to the derivatives IDA and IDX. These data suggest that more lipophilic anthracycline derivatives may also be active in MDR cell systems.

Embedding time granularity in a logical specification language for synchronous real-time systems

Abstract: Formal methods have proved to be highly beneficial in the requirements specification phase of software production and are particularly valuable in the development of real-time applications (the most critical software systems). Unfortunately, most common specification languages are inadequate for real-time applications because they lack a quantitative representation of time. In this paper, we define a logical language to specify the temporal constraints of the wide-ranging class of real-time systems whose components have dynamic behaviours regulated by very different time constants. We motivate the need for allowing the consistent treatment of different time scales in formal specifications of these systems with the purpose of enhancing the naturalness and practical usability of the notation. The logical specification language is based on a revised version of the specification language TRIO. We first present the features of the basic logical language; then, we semantically and axiomatically define its granularity extension in a topological logic framework. Finally, we show some examples of its application.

Cystoid macular oedema after extracapsular cataract extraction and intraocular lens implantation in diabetic patients without retinopathy.

Abstract: Postoperative onset or aggravation of cystoid macular oedema (CMO) in diabetic patients after extracapsular cataract extraction (ECCE) with intraocular lens (IOL) implantation is a frequent problem. At present little is known about the occurrence and prognosis of this complication in diabetics with no clinically detectable diabetic retinopathy (DR). Twenty five diabetic eyes (24 subjects) without DR and 45 normal eyes (44 subjects) were studied before surgery and 30, 90, 180, 360 days after ECCE and posterior chamber IOL implantation. Fluorescein angiography was performed at each examination. The frequency of angiographic CMO in the two groups was comparable 30 days after surgery but was significantly higher in diabetic eyes at 90, 180, and 360 days. This finding is probably related to an impairment of the blood-retinal barrier in diabetics. Final visual acuity, however, was similar in the two groups.

Expression of multidrug resistance gene (MDR-1) in human normal leukocytes.

Abstract: BACKGROUND The mdr-1 gene, which codes for a 170-kd transmembrane glycoprotein (P170), is frequently overexpressed in multidrug resistant (MDR) tumor cell lines and in spontaneous tumors, including leukemia and lymphoma. However, it is also constitutively expressed as a normal gene in normal tissues. METHODS We used human mdr-1 cDNA and three anti-P170 monoclonal antibodies (MoAbs: MRK-16, C-219 and JSB-1) to investigate the normal peripheral blood leukocyte content of mdr-1 specific mRNA and of P170 through immunocytochemistry and flow cytometry. RESULTS We did not find any increase in mdr-1-specific mRNA, while small amounts of P170 were easily detectable in about two thirds of the lymphocytes and monocytes and in about one third of the granulocytes. The level of P170 expression in leukocytes was similar to that found in non-MDR tumor cell lines. CONCLUSIONS mdr-1 is constitutively expressed in human normal leukocytes at levels that cannot significantly affect drug resistance. Accordingly, low-level mdr-1 expression in leukemic cells should not be considered a label of pleiotropic drug resistance.

Selection against inbreds in early life-cycle phases in Pinus leucodermis Ant.

Abstract: Conifers are self-compatible hermaphroditic plants which usually show very low levels of selfing and severe inbreeding depression. Positive fixation indices are observed in the seed stage owing to partial selfing but not in the adult stage and selection against inbreds has been frequently invoked to explain this observation. To determine the stage of elimination of inbreds in Pinus leucodermis Ant., a narrow-ranged and relic species characterized by 18-28 per cent selfing rates, fixation indices at isozyme gene loci were estimated in nursery grown individuals at three different juvenile life-cycle phases and in adult parent trees. Two populations with different levels of selfing were studied. In both populations a deficiency of heterozygotes as a result of selfing was observed in dormant and in germinated embryos, while an excess of heterozygotes comparable with that of the adult trees was found in 5-year-old plantlets. Young plantlets of the same two populations grown in the wild also had negative fixation indices confirming that selection takes place in the first years of growth.

Pharmacokinetic optimisation of tricyclic antidepressant therapy.

Abstract: Pharmacokinetics has greatly contributed to the elucidation of the variability in clinical response to antidepressants in terms of differences in plasma concentrations due to genetic constitution, age, associated diseases and drug interactions. Despite no general agreement, therapeutic and toxic concentrations have been suggested for some tricyclic antidepressants (TCAs) [amitriptyline, nortriptyline, imipramine, desipramine]. Predictive techniques may be implemented on the basis of which starting TCA dosages may be selected to reach more rapidly those concentrations at which efficacy is more probable. Therapeutic drug monitoring may thereafter assist the clinician in refining the individualisation of the dosage regimen.