Heart and systemic effects of statin pretreatment in a rat model of abdominal sepsis. Assessment by Tc99m-sestamibi biodistribition

PURPOSE: To evaluate the heart and the Tc-99m-sestamibi biodistribution after statin pretreatment in a rat model of abdominal sepsis. METHODS: Twenty-four Wistar rats were randomly distributed into four groups (n=6 per group): 1) sepsis with simvastatin treatment, 2) sepsis with vehicle, 3) sham control with simvastatin and 4) sham control with vehicle. 24 hours after cecal ligation and puncture rats received 1.0MBq of Tc-99m-sestamibi i.v. 30min after, animals were euthanized for ex-vivo tissue counting and myocardium histological analysis. RESULTS: Myocardial histologic alterations were not detected 24 hours post-sepsis. There was significantly increased cardiac Tc-99m-sestamibi activity in the sepsis group with simvastatin treatment (1.9$\pm$0.3%ID/g, p<0.001) in comparison to the sepsis group+vehicle (1.0$\pm$0.2% ID/g), control sham group+ simvastatin (1.2$\pm$0.3% ID/g) and control sham group (1.3$\pm$0.2% ID/g). Significant Tc-99m-sestamibi activity in liver, kidney and lungs was also detected in the sepsis group treated with simvastatinin comparison to the other groups. CONCLUSIONS: Statin treatment altered the biodistribution of Tc-99m-sestamibi with increased cardiac and solid organ activity in rats with abdominal sepsis, while no impact on controls. Increased myocardial tracer activity may be a result of a possible protection effect due to increased tissue perfusion mediated by statins

Serum Albumin Is Inversely Associated With Portal Vein Thrombosis in Cirrhosis

We analyzed whether serum albumin is independently associated with portal vein thrombosis (PVT) in liver cirrhosis (LC) and if a biologic plausibility exists. This study was divided into three parts. In part 1 (retrospective analysis), 753 consecutive patients with LC with ultrasound-detected PVT were retrospectively analyzed. In part 2, 112 patients with LC and 56 matched controls were entered in the cross-sectional study. In part 3, 5 patients with cirrhosis were entered in the in vivo study and 4 healthy subjects (HSs) were entered in the in vitro study to explore if albumin may affect platelet activation by modulating oxidative stress. In the 753 patients with LC, the prevalence of PVT was 16.7%; logistic analysis showed that only age (odds ratio [OR], 1.024; P = 0.012) and serum albumin (OR, -0.422; P = 0.0001) significantly predicted patients with PVT. Analyzing the 112 patients with LC and controls, soluble clusters of differentiation (CD)40-ligand (P = 0.0238), soluble Nox2-derived peptide (sNox2-dp; P &lt; 0.0001), and urinary excretion of isoprostanes (P = 0.0078) were higher in patients with LC. In LC, albumin was correlated with sCD4OL (Spearman's rank correlation coefficient [r(s)], -0.33; P &lt; 0.001), sNox2-dp (r(s), -0.57; P &lt; 0.0001), and urinary excretion of isoprostanes (r(s), -0.48; P &lt; 0.0001) levels. The in vivo study showed a progressive decrease in platelet aggregation, sNox2-dp, and urinary 8-iso prostaglandin F2 alpha-III formation 2 hours and 3 days after albumin infusion. Finally, platelet aggregation, sNox2-dp, and isoprostane formation significantly decreased in platelets from HSs incubated with scalar concentrations of albumin. Conclusion: Low serum albumin in LC is associated with PVT, suggesting that albumin could be a modulator of the hemostatic system through interference with mechanisms regulating platelet activation

ESSAY ON INDUSTRIAL ORGANIZATION

La presente tesi fornisce un contributo originale al dibattito esistente tra gli economisti industriali sul rapporto tra concorrenza e asimmetrie informative. Infatti, l’obiettivo principale di questo lavoro consiste nell'investigare, da un punto di vista teorico (e supportato dall'evidenza empirica), come alcune barriere informative presenti nel mercato influenzano le strategie imprenditoriali in diversi contesti competitivi, fornendo implicazioni di policy per autorità garanti della concorrenza e a tutela del consumatore. Nello specifico, il primo capitolo esamina gli incentivi di una impresa dominante in un mercato a monte a offrire contratti di esclusiva ad un monopolista nel mercato a valle, quando vi è incertezza riguardo alla domanda finale dei consumatori. Nei capitoli seguenti, invece, l’analisi si caratterizza dalla presenza del concetto comportamentale di "avversione alla perdita", particolarmente rilevante nelle decisioni di acquisto dei cosiddetti "beni di esperienza". In questi mercati le imprese possono decidere liberamente di permettere test sui propri prodotti prima del loro acquisto, modificando quindi l’utilità attesa dei consumatori. Il secondo capitolo analizza le strategie di vendita per un monopolista. Il terzo capitolo, invece, esamina l’equilibrio di mercato in un contesto competitivo e come l’utilizzo di test sui prodotti possa essere adoperato come strumento collusivo.This dissertation provides an original contribution to the existing debate between industrial economists on the relationship between competition and information asymmetries. Indeed, the main goal of this work consists in investigating, from a theoretical point of view (and supported by empirical evidence), how some informational frictions in the market affect firm’s strategies in different competitive environments, providing policy implications for competition and consumer protection authorities. Specifically, the first chapter looks at the incentives of a dominant firm in an upstream market to offer exclusive dealing contracts to a monopolist in the downstream market, when there is uncertainty about consumer demand. In the following chapters, instead, the analysis is characterized by the presence of the behavioral concept of "loss aversion", which is particularly relevant in the purchase decisions of the so-called "experience goods". In these markets, firms can freely decide to allow product experimentation before purchase, thus modifying the consumers' expected utility. The second chapter analyzes the monopolist's sales strategies. The third chapter, instead, examines the market equilibrium in a competitive environment and how product experimentation can be used as a collusive device

Collusion Sustainability with a Capacity Constrained Firm

We study an infinitely repeated oligopoly game in which firms compete on quantity and one of them is capacity constrained. We show that collusion sustainability is non-monotonic in the size of the capacity constrained firm, which has little incentive to deviate from a cartel. We also present conditions for the emergence of a partial cartel, with the capacity constrained firm being excluded by the large firms or self-excluded. In the latter case, we show under which circumstances the small firm induces a partial conspiracy that is Pareto-dominant. Implications for cartel identification and enforcement are finally discussed

History-Based Price Discrimination with Imperfect Information Accuracy and Asymmetric Market Shares

In this paper, we consider a duopoly model with history-based price discrimination where firms have imperfect information on consumers’ purchase history and asymmetric inherited market shares. We analyze the effects of the degree of information accuracy on market configuration, firms profits, and consumers surplus. We find that the equilibrium market structure is jointly determined by the size of the inherited market shares and the degree of information accuracy. With high degrees of information accuracy firms are more likely to use symmetric pricing strategies, both poaching rival’s consumers. Conversely, with low degrees of information accuracy or highly asymmetric market shares, firms adopt different pricing strategies and price discrimination is enforced only by the firm inheriting the smaller quota of market shares. We show that, everything else equal, a higher degree of information accuracy has a non-monotonic effect on firms’ profits and a decreasing effect on social welfare; the effect on consumer surplus varies according to the equilibrium market configuration

Analisi proteomica dell'epicarpo di Limone (Citrus limon [L.] Burm.) Le qualità biochimiche del limone di Rocca Imperiale

Dottorato di Ricerca in Biologia Vegetale, XXII Ciclo, a.a.2006-2009Università della Calabri

Personalized Pricing with Imperfect Customer Recognition

We consider a duopoly model where firms can identify only a share of consumers, which is positively correlated with the consumer’ preferences. Firms charge personalized prices to the consumers they can recognize and a uniform price to the rest of consumers. The firms’ available information is given by the combination of two factors: the intensive margin, which determinesthe share of consumers the firms can recognize in each single location, and the extensive margin, which determines how many locations the firms can identify. Different market configurations emerge according to the size of these margins. We characterize the values of the intensive and extensive margins that maximize firms’ profits, and we show that profits are non-monotonic. We also show that the composition, in addition to the size, of the available information – i.e., the mix of these margins – affects firms’ profits significantly. Implications for regulatory policies concerning the protection of consumers’ information are finally discussed

History-Based Price Discrimination with Imperfect Information Accuracy and Asymmetric Market Shares

The paper considers a duopoly model in which firms inherited asymmetric market shares and history-based price discrimination is viable. However, firms can identify only a share of their own consumers depending to the degree of information accuracy. We derive the pricing strategies and we analyze the relationship between information accuracy and asymmetric market shares, showing under which circumstances there exists an equilibrium in pure strategies. We show that history-based price discrimination makes the dominant firm’s profits always lower than those of the rival, with an ambiguous effect of the information accuracy on industry profits. Moreover, we prove that the level of information accuracy has a decreasing effect on social welfare, while it affects consumer surplus non-monotonically, according to the size of asymmetry in the inherited market shares

Imperfect history-based price discrimination with asymmetric market shares

We consider a duopoly model with history-based price discrimination where firms inherit asymmetric shares of consumers that they might partly recognize according to the degree of information completeness. We analyze the impact of the amount of information on market configuration, profits and welfare. With high degrees of information completeness and sufficiently small asymmetries in the market shares, firms are more likely to use aggressive pricing strategies, both poaching rival's consumers. Otherwise, firms adopt different pricing strategies and price discrimination is enforced only by the smaller firm. Greater information completeness has a non-monotonic effect on profits and a decreasing effect on welfare. Finally, we show that the case with perfect information is a special case whose results do not hold when even a small degree of uncertainty is introduced in the game