Cytokine induction in human mononuclear cells stimulated by IgG-coated culture surfaces and by IgG for infusion

The effect of IgG on cytokine production by human mononuclear cells (MNC) was studied. Tumor necrosis factor-alpha (TNF) was determined both by bioassay and by immunoassay. Interleukin-1 (IL1) was measured by a thymocyte costimulator assay, which was shown to be completely inhibitable by polyclonal anti-IL1. Precautions were taken to avoid inadvertent exposure of the studied cells to endotoxin. In a first model, TNF and IL1 production by adherent MNC in IgG-coated cluster plates were determined. IgG induced a strong TNF response, usually leveling off after 6 hr, and was comparable in kinetics and magnitude with an LPS-induced response. The thymocyte co-stimulatory activity response was relatively weak and peaked at 6 hr. In contrast, LPS-induced co-stimulatory activity production steadily increased over 24 hr. In a second model, MNC in suspension cultures containing autologous serum were exposed to IgG for intravenous use (IgG-IV). Cells exposed to IgG-IV produced higher amounts of cytokines than control counterparts and were primed for enhanced production of cytokines upon a second, unrelated stimulus. This implies that the effect of IgG-IV on suspended MNC resembles that of surface-adsorbed IgG and raises the possibility that cytokine release is an integral part of the mechanism of action of infused IgG. Evidence is presented suggesting that both surface IgG and IgG-IV act directly on monocytes, in a Fc-dependent manner.

Bipartite graphs and quasipositive surfaces

We present a simple combinatorial model for quasipositive surfaces and positive braids, based on embedded bipartite graphs. As a first application, we extend the well-known duality on standard diagrams of torus links to twisted torus links. We then introduce a combinatorial notion of adjacency for bipartite graph links and discuss its potential relation with the adjacency problem for plane curve singularities.

Implicit motives and basic need satisfaction in extreme endurance sports.

Previous research has shown that the effects of basic psychological needs on the flow experience in sports are moderated by implicit motives. However, so far, only leisure and health-oriented sports have been analyzed. In a pilot study and a main study (N = 29, 93), we tested whether the implicit achievement and affiliation motives interact with the need for competence and the need for social relatedness satisfaction, respectively, to predict flow experience and well-being in extreme endurance athletes. Results showed that highly achievement-motivated individuals benefited more from the need for competence satisfaction in terms of flow than individuals with a low achievement motive did. In addition, highly affiliation-motivated individuals whose need for social relatedness is satisfied reported higher positive affect and lower exercise addiction scores than athletes with a low motive. We discuss the differential effects of the interplay between the achievement and affiliation motives and basic needs on different outcome variables.

The implicit affiliation motive moderates cortisol responses to acute psychosocial stress in high school students

It has been previously shown that the implicit affiliation motive – the need to establish and maintain friendly relationships with others – leads to chronic health benefits. The underlying assumption for the present research was that the implicit affiliation motive also moderates the salivary cortisol response to acute psychological stress when some aspects of social evaluation and uncontrollability are involved. By contrast we did not expect similar effects in response to exercise as a physical stressor. Fifty-nine high school students aged M = 14.8 years were randomly assigned to a psychosocial stress (publishing the results of an intelligence test performed), a physical stress (exercise intensity of 65–75% of HRmax), and a control condition (normal school lesson) each lasting 15 min. Participants’ affiliation motives were assessed using the Operant Motive Test and salivary cortisol samples were taken pre and post stressor. We found that the strength of the affiliation motive negatively predicted cortisol reactions to acute psychosocial but not to physical stress when compared to a control group. The results suggest that the affiliation motive buffers the effect of acute psychosocial stress on the HPA axis.

The effect of age and time perspective on implicit motives

People differ in how open-ended or limited they perceive their future. We argue that individual differences in future time perspective affect the activation of implicit motives. Perceiving the time remaining for the satisfaction of one’s motives as limited should be associated with a higher activation of these motives than perceiving one’s future as more open-ended. Given that future time perspective decreases across adulthood, older adults should score higher on implicit motives than younger adults. This hypothesis was supported in a study with young (n = 53, age M = 25.60 years) and older adults (n = 55, age M = 68.05 years). Additionally, an experimental manipulation of future time perspective showed that age-related differences in implicit motives are influenced by future time perspective. These findings demonstrate that future time perspective is an important factor to explain the strength of motives.

Implicit Motives of Elite Athletes, Sport Students, and Non-Sport Students: Power, Affiliation, and Achievement

Research on performance and participation in (elite) sports has predominantly focused on variables relating to the achievement motive. However, some authors describe that athletes in interactive sports (e.g. tennis) are assumed to exhibit a strong power motive in order to win competitive matches, usually resulting in the demonstration of dominance or the experience of inferiority. The affiliation motive, by contrast, is not functional in elite sports due to their competitive rather than social character. In the present chapter we discuss how the three basic implicit motives of power, affiliation, and achievement relate to the sports field and describe how they can affect athletes’ performance. We present empirical evidence for the existence of different strengths of the three basic motives in three studies with elite athletes (Study 1), non-elite athletes (sport students, Study 2), and non-sport students infrequently involved in sports (Study 3). Our results suggest that elite athletes show higher levels of the implicit power motive compared to sport students, who in turn have higher power motives than non-sport students. Surprisingly, elite athletes do not differ from non-sport students regarding their implicit achievement motive. Moreover, non-sport students exhibit higher implicit affiliation motive scores than sport students and elite athletes. We propose that research on motivational processes of highly competitive athletes should – in addition to the achievement motive – focus more on motive themes like the implicit motives of power and affiliation.

Explicit vs implicit affiliation motives predict different social behavior in sports competition

Objectives The present study investigated the predictive value of the explicit and implicit affiliation motive for social behavior in sport competitions. From an information processing perspective, an explicit motive is linked to verbal cues and respondent behavior. The implicit motive in turn is linked to nonverbal stimuli and operant behavior (McClelland, Koestner, & Weinberger, 1989; Schultheiss, 2008). Both respondent affiliative behavior (e.g., verbal interactions with teammates) and operant nonverbal social behavior (e.g., pleasant to opponents) can be observed in racquet sports team competitions. Design & Methods Fifty-two male racquet sportsmen completed the Personality Research Form (explicit affiliation motive) and the Operant Motive Test (implicit affiliation motive). Motive measures were used to predict social behavior during competitions using multiple regression analyses. To this aim real competitive matches were videotaped and analyzed. Results Results show that the explicit affiliation motive is associated with time spent in verbal team contact. The implicit affiliation motive, by contrast, is linked to pleasant nonverbal behavior shown toward opponents. Conclusions Findings suggest that implicit and explicit affiliation motives predict different kinds of social behavior in sports competition respectively. Indirect motive measures may be of additional predictive value for different behavior in real sports settings.