Differential patterns of PMN-elastase and type III procollagen peptide in knee joint effusions due to acute and chronic sports injuries

In 38 traumatic knee joint effusions the proteolytic enzyme PMN-elastase (PMN-E) and the repair marker procollagen III aminoterminal peptide (PIIINP) were determined. According to the period between trauma and first aspiration of the effusion, the patients were divided into 3 groups. Group I (17 patients; period between trauma and first aspiration not longer than 72 hours) showed high concentrations of PMN-E (up to 5400 ng/ml) and low concentrations of PIIINP (<13 U/ml). Group II (11 patients; aspiration within 4 to 14 days) had mean PMN-E and PIIINP concentrations of 125.6 ng/ml and 52.1 U/ ml, respectively. In group III (10 patients, aspiration after 14 days) mean PMN-E concentration was 123.8 ng/ml and mean PIIINP concentration was 63.4 U/ml. Graphic depiction of PMN-E and PIIINP levels in each individual sample as a function of time between trauma and fluid collection revealed highly increasing PMN-E levels during the first 24 posttraumatic hours, followed by rapidly decreasing levels within 72 hours post trauma, and no change after the 4th posttraumatic day. In contrast, PIIINP increased continuously up to the first posttraumatic week and stayed at high levels up to 90 days (end of the observation period). The differential patterns of PMN-E and PIIINP concentration in knee joint effusions may be useful in estimating the period between trauma and first treatment (aspiration of effusion) and should, therefore, be helpful in detecting degenerative lesions, which seem to be characterized by low PMN-E concomitantly with high PIIINP levels

Characteristics of Alveolar Bone Marrow Cells from Patients Undergoing Dental Extractions or Dental Implant Therapy

Alveolar bone marrow stromal cells (aBMSCs) play important roles in craniofacial wound healing. To establish an easy, efficient and reliable method to harvest aBMSCs, we compared three different methods: extraction socket aspiration, osteotomy aspiration and bone core digestion. Samples of aBMSC were collected from two groups of subjects. Group 1 (dental extraction): after dental extraction, 22.5-gauge needles were used to collect 0.5-1cc marrow aspirate. Group 2 (dental implant): during implant surgeries, bone core and 0.5-1cc marrow aspirate were obtained from the osteotomy. Samples were cultured in petri dishes and attached cells were expanded. The population doubling time (PDT), surface markers, and osteogenic differentiation potential of these cells were studied. In total 12 subjects were enrolled in the study. The success rates of generating aBMSCs from extraction socket aspiration, osteotomy aspiration and bone core digestion were 42.8% (3/7), 40% (2/5) and 80% (4/5), respectively. Cells from extraction socket aspiration had the fastest proliferation rate among the three sample types, followed by bone core and osteotomy aspiration, as shown in PDTs and DNA fold changes. After isolation and expansion, all the aBMSCs expressed high levels of CD 73, CD90, and CD105, however, the expression of CD146 varied among the cells. Cells derived from bone core had the highest ALP activity after osteogenic induction, followed by cells from osteotomy aspiration, and then extraction aspiration. Taken together, bone core samples obtained during implant surgery is a more reliable source for generating aBMSCs and aBMSCs harvested from different methods may have different characteristics

Cooperation as a Result of Learning with Aspiration Levels

It is shown that a win-stay, lose-hift behavior rule with endogenous aspiration levels yields cooperation in a certain class of games. The aspiration level in each round equals the current population average. The class of games includes the prisoner's dilemma and Cournot oligopoly and thus yields an explanation for cooperation and collusion.cooperation

Aspiration Levels and Educational Choices An experimental study

The explanation of social inequalities in education is still a debated issue in economics. Recent empirical studies tend to downplay the potential role of credit constraint. This article tests a different potential explanation of social inequalities in education, specifically that social differences in aspiration level result in different educational choices. Having existed for a long time in the sociology of education, this explanation can be justified if aspiration levels are seen as reference points in a Prospect Theory framework. In order to test this explanation, this article applies the method of experimental economics to the issue of education choice and behaviour. One hundred twenty-nine individuals participated in an experiment in which they had to perform a task over fifteen stages grouped in three blocks or levels. In order to continue through the experiment, a minimum level of success was required at the end of each level. Rewards were dependent on the final level successfully reached. At the end of each level, participants could either choose to stop and take their reward or to pay a cost to continue further in order to possibly receive higher rewards. To test the impact of aspiration levels, outcomes were either presented as gains or losses relative to an initial sum. In accordance with the theoretical predictions, participants in the loss framing group choose to go further in the experiment. There was also a significant and interesting gender effect in the loss framing treatment, such that males performed better and reached higher levels. Expliquer les inégalités sociales en éducation demeure un défi pour les économistes. Des études récentes tendent à indiquer que les contraintes de crédit ne joueraient pas un rôle déterminant dans l’explication. Notre étude examine l’importance de niveaux d’aspirations sociales différentes pour expliquer les différences observées dans les choix éducationnels. Cette explication trouve sa logique en associant les aspirations sociales à des points de référence dans le cadre de la théorie des perspectives (prospect theory). Notre article mobilise l’économie expérimentale pour étudier la question des choix éducationnels dans ce contexte. Cent trente-neuf sujets ont participé à une expérience dans laquelle ils devaient réaliser une tâche distribuée sur quinze étapes regroupées en blocs ou niveaux. Pour poursuivre l’expérience, un minimum de succès dans les tâches réalisées devait être atteint. À la fin de chaque niveau, les participants choisissaient d’arrêter et d’encaisser leurs gains acquis ou de poursuivre contre un tarif donné pour espérer réaliser des gains supérieurs. Pour tester l’impact des différents niveaux d’aspirations, les résultats étaient mesurés comme des gains ou des pertes relativement à un montant donné. En conformité avec les prédictions théoriques, les participants dans le traitement perte ont choisi de poursuivre plus souvent l’expérience que ceux dans le traitement gain. Nous avons également noté un effet lié au genre du participant dans le traitement perte, avec les hommes performant mieux que les femmes et atteignant des niveaux supérieurs.education inequality, prospect theory, experimental economics, inégalité en éducation, théorie de la prospective, économie expérimentale

Asset Prices in an Overlapping Generations Model with Case-Based Decision Makers with Short Memory

I consider an economy, populated by case-based decision makers with one-period memory. Consumption can be transferred between the periods by the means of a riskless storage technology or a risky asset with iid dividend payments. I analyze the dynamics of asset holdings and asset prices. Whereas an economy in which the investors have low aspiration levels exhibits constant prices and asset holdings, investors with high aspiration levels create cycles, which may be stochastic or deterministic. Arbitrage possibilities, deviation of the price from the fundamental value, predictability of returns and excessive volatility are shown to obtain in a market with case-based investors.

Tempus Fugit: Time Pressure in Risky Decisions

We study the effects of time pressure on risky decisions for pure gain prospects, pure loss prospects, and mixed prospects involving both gains and losses. In an experiment we find that risk aversion for gains is robust under time pressure whereas risk seeking for losses turns into risk aversion under time pressure. For mixed prospects, subjects become more loss averse and more gain seeking under time pressure, depending on the framing of the prospects. The results suggest the importance of aspiration levels under time pressure. We discuss the implications of our findings for decision making situations that involve time pressure.time pressure; risky decisions; risk aversion; loss aversion; gain seeking; aspiration level

The effects of exogenous lipid on THP-1 cells : an in vitro model of airway aspiration?

Chronic inflammatory diseases of the airways are associated with gastro-oesophageal reflux (GOR) and aspiration events. The observation of lipid laden macrophages (LLM) within the airway may indicate aspiration secondary to GOR. The proposed mechanism, that lipid droplets from undigested or partially digested food are aspirated leading to accumulation in scavenging macrophages led us to hypothesise that an activated population of LLM could interact with other immune cells to induce bronchial inflammation. To test this, we generated an in vitro model using differentiated THP-1 cells which were treated with a high fat liquid feed. Here we show that THP-1 cells can take up lipid from the high fat feed independent of actin polymerisation or CD36 dependent phagocytosis. These cells did not exhibit M1 or M2 polarisation. Gene array analysis confirmed over 8000 genes were upregulated by at least two fold following high fat exposure and IL-8 was the most upregulated gene. Pathway analysis revealed upregulation of genes known to be involved in chronic obstructive pulmonary disease (COPD) pathophysiology. We suggest that aspiration and macrophage phagocytosis may be important mechanisms in the aetiology of diseases such as COPD and cystic fibrosis which are characterised by high levels of IL-8 within the airways

Is there an optimization in bounded rationality? The ratio of aspiration levels

Simon’s (1955) famous paper was one of the first to cast doubt on the validity of rational choice theory; it has been supplemented by many more papers in the last three and a half decades. Nevertheless, rational choice theory plays a crucial role in classical and neoclassical economic theory, which presumes a completely rational agent. The central points characterizing such an agent are: (1) The agent uses all the information that is given to him. (2) The agent has clear preferences with respect to the results of different actions. (3) The agent has adequate competences to optimize his decisions. As an alternative to this conception, Simon (1955) himself suggests the concept of “bounded rationality”. In this context, Simon (1956) discusses a principle, which he names the “satisficing principle” (for explanations with respect to this notion cf. Gigerenzer & Todd 1999, p. 13). It assumes that, instead of searching for an optimal action, the search for an action terminates if an alternative has been found that satisfies a given “aspiration level”. It will be demonstrated that although the satisficing principle is nothing but a heuristic, there is a mathematical optimization at work when aspiration levels are used in this kind of problems. The question about the optimal aspiration level can be posed. Optimization within the framework of bounded rationality is possible. However, the way in which such an optimization can be achieved is very simple: Optimal thresholds in binary sequential decisions rest with the median.