118,021 research outputs found
Warm hepatic ischemia in pigs: effects of L-arginine and oligotide treatment
No full textReperfusion injury represents a key event leading to graft nonfunction. Maintaining adequate nitric oxide levels and stimulating vasodilator synthesis can probably minimize endothelial damage. The aim of this study was to investigate the effect of L-arginine, a substrate of nitric oxide synthesis, and oligotide, a promoter of prostacyclin synthesis, on liver function and morphology after warm ischemia-reperfusion injury. After constructing a side-to-side portacaval shunt, ischemia was induced by clamping the hepatic hilum for 2 h above the shunt, in 19 female pigs divided into a control group (n = 7), an L-arginine treatment group (n = 6), and an oligotide treatment group (n = 6). Liver function tests and measurements of serum and red blood cell malondialdehyde and plasma nitric oxide levels were performed before reperfusion and at 1, 10, 60, and 120 min after reperfusion. Liver biopsies, taken before reperfusion and at 30 min and 7 days after reperfusion, were analyzed for tissue malondialdehyde, histological-ultrastructural features, and apoptosis evaluation. Thirty minutes after reperfusion, liver malondialdehyde, sinusoidal congestion, necrosis, and apoptosis were significantly lower in the L-arginine group than in the controls (p < .05). On postoperative day 7, tissue malondialdehyde decreased, while plasma nitric oxide and hepatocyte glycogen content were increased in the L-arginine group compared to controls (p < .05). This study demonstrates the protective effect of L-arginine on hepatic lipoperoxidation and liver morphology in a pig model of warm ischemia-reperfusion injury. The increased plasma levels of nitric oxide a week after ischemia-reperfusion injury support the hypothesis that it has a role in preventing liver damage. The same beneficial effect was not confirmed for oligotide
Le scritture documentarie tra oriente e occidente: qualche osservazione
No full textNel contributo si esaminano in chiave comparativa i caratteri paleografici e del formulario dei documenti bizantini orientali e occidentali, compresi entro l'XI secolo. Si verifica che i documenti prodotti in Puglia presentano elementi in comune con quelli orientali, mentre quelli calabresi se ne differenziano. La ragione risiede nella maggiore possibilita' di contatti tra la Puglia e l'Oriente, che fece di questa regione italiana un luogo strategico, anche dal punto di vista politico nelle guerre combattute da Bisanzio contro Arabi e gli Slavi
Composición química del aceite de palta : variedad "Lula" (Provincia de Jujuy)
No full textEste trabajo tiene por objeto continuar el estudio de composiciónde aceites de pulpa de paltas argentinas iniciado con latesis de Jorge Alvarez (l), quien estableció las característicasfísico-químicas y composición del aceite correspondiente a lavariedad "Fuerte 40" (Calilegua, Pcia. de Jujuy). Enéste caso, se estudia en la misma forma, el aceite procedentede frutos de la variedad "Lula", cosechados en Ledesma, Provincia de Jujuy .Fil: Rigotti, Juan Pedro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Composición química del aceite de palta : variedad "Lula" (Provincia de Jujuy)
No full textEste trabajo tiene por objeto continuar el estudio de composiciónde aceites de pulpa de paltas argentinas iniciado con latesis de Jorge Alvarez (l), quien estableció las característicasfísico-químicas y composición del aceite correspondiente a lavariedad "Fuerte 40" (Calilegua, Pcia. de Jujuy). Enéste caso, se estudia en la misma forma, el aceite procedentede frutos de la variedad "Lula", cosechados en Ledesma, Provincia de Jujuy .Fil: Rigotti, Juan Pedro. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Update on the use of montelukast in pediatric asthma
No full textCysteinyl leukotrienes are inflammatory bioactive lipids produced by various cells. They are present in increased amounts in
airway secretions of all different asthma phenotypes and can induce all the inflammatory changes observed in the airways of
asthmatic patients. For this reason, an attempt to inhibit the actions of these mediators through the use of cysteinyl receptor
antagonists appears rational. Montelukast belongs to this new class of drugs, which has been proved effective in asthmatic
children and its safety profile is comparable with that of placebo. The major advantages of this drug are its once-daily oral
administration, which increases adherence to the therapeutic regimen; its long-term persistent efficacy in the prevention of
exercise-induced bronchoconstriction; its possible preventive activity on viral-induced asthma exacerbations; and its complementary
and additive effects when used with inhaled corticosteroids. As established for all drugs commonly used in the
treatment of asthma, there is an interindividual variability also in response to montelukast. Therefore, it is important that
caregivers evaluate treatment effect objectively in every asthmatic child to provide the single patient with a therapeutic regimen
allowing the best quality of life
The protective effects of L-arginine after liver ischaemia/reperfusion injury in a pig model.
No full textHepatic ischaemia/reperfusion is characterized by circulatory and metabolic derangement, liver dysfunction, and tissue damage. To evaluate the role of L-arginine, a substrate of nitric oxide, in ischaemia/reperfusion injury, total liver ischaemia was induced for 120 min in 22 Landrace x Large White female pigs, which were randomly assigned to a treatment group (10 animals) or a control group (12 animals). An L-arginine bolus (540 mg/kg i.v.) was administered to the treatment group 1 h before clamping the hepatic hilum, at clamping, at reperfusion, and at 1 and 2 h after reperfusion. The control animals received normal saline and an i.v. infusion. Liver function tests and analysis of serum, erythrocyte, and tissue malondialdehyde contents were performed at commencement of laparotomy, before reperfusion, and at 30 min and 7 days after reperfusion. Liver biopsies were taken at laparotomy, at 30 min, and at 7 days after reperfusion for histological and ultrastructural examination. Assessment of apoptosis included in situ end-labelling analysis and DNA gel electrophoresis. Survival at 7 days was better in the treated animals than in the controls (9/10 vs. 7/12). Tissue malondialdehyde content, aspartate aminotransferase, and lactate dehydrogenase levels were lower in the treatment group, in which morphological changes were significantly less evident than in the controls 30 min after reperfusion. At 7 days, differences between the groups with respect to cell integrity were apparent only on ultrastructural analysis. Glycogen content, 7 days after reperfusion, was higher in the treatment group than in the controls: 70.25 per cent vs. 21.66 per cent positive hepatocytes (score 3 vs. score 1). Multiparametric analysis showed fewer apoptotic cells in the treatment group at all times. Our data show that the administration of L-arginine reduces damage to liver tissue after ischaemia/reperfusion injury in a pig model. This may be explained not only by the known vasodilator, anti-aggregation, and superoxide inactivation effects of increased nitric oxide release, but possibly also by some other action of L-arginine, such as its influence on cellular metabolism
Role of ventilator and nasal interface in pressure transmission during neonatal intermittent positive pressure ventilation: A bench study
No full textWe aimed at evaluating pressure transmission and stability during non-synchronized neonatal nasal intermittent positive pressure ventilation (NIPPV) delivered using five mechanical ventilators and three nasal interfaces. An artificial nose–throat model was connected to a mechanical analog of the infant respiratory system and a breath generator. Ventilation was administrated via a nasal mask (NM), short bi-nasal prongs (SBN), or RAM® cannula. We applied positive end-expiratory pressures (PEEP) of 5 and 10 cmH2O, inspiratory pressures (PIP) of 15 and 30 cmH2O, inspiratory times of 0.23, 0.42, and 0.57 s. Measurements were performed with leaks of 0, 1.5, and 4 L/min. The pressure was measured at the airways opening (PAW) and the glottis (PGL). The difference between set and delivered pressures (PAW) was less than ±1 cmH2O for all ventilators. We documented a significant difference between PAW and PGL in the presence of leaks. With 4 L/min leaks, PEEP dropped by 43%, 49%, and 63% with NM, SBP, and RAM® cannula, respectively; PIP dropped by 58%, 64%, and 74%. On average, the SD of PEEP fluctuations was ±0.60 and ±2.50 cmH2O for PAW and PGL; the breath-by-breath SD of PIP was ±0.77 and ±2.06 cmH2O. During NIPPV, the PIP and PEEP transmission to the glottis is markedly lower than the set values and highly variable. The impact of leaks and nasal interface is much more significant than the differences in ventilators' performance on the efficacy of pressure transmission and stability of non-synchronized ventilator-generated NIPPV
Optimal design of experiments with simulation models of nearly saturated queues
No full textexperimental design;simulation models;queueing network;regression analysis
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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