Prediction of Secondary Structure of Proteins. A Comparison of the ?,Ψ Angles Previously Predicted for Cytochrome c with Recent X-Ray Crystallographic Findings

Newer data from the x-ray crystallographic studies of tuna heart ferrocytochrome c have increased the number of residues in alpha-helical segments. This provided an objective test of our method of predicting varphi,Psi values for cytochrome c using the sequences of 18 cytochromes c and twenty 20 x 20 tables for the varphi,Psi values of tripeptides in 10 other proteins whose three-dimensional structures were known from x-ray crystallographic studies. Of the 32 residues now considered from x-ray data to be in alpha-helices, 27 had been predicted to be in the alpha-helical domain.     

Cue-Induced Smoking Urges Deplete Cigarette Smokers’ Self-Control Resources

Background

Exposure to smoking-related cues leads to increased urge to smoke in regular cigarette smokers and resisting these urges requires considerable self-control.

Purpose

Adopting a resource depletion model, two studies tested the hypothesis that resisting smoking urges depletes self-control resources.

Methods

Adopting a within-participants randomized cross-over design, participants (study 1, N?=?19; study 2, N?=?32) were exposed to smoking-related (study 1: smoking images; study 2: cigarette cue-exposure task) and neutral (study 1: neutral images; study 2: drinking-straw task) cues with presentation order randomized. After each cue set, participants completed self-control tasks (study 1: handgrip task; study 2: handgrip and Stroop tasks), performance on which constituted dependent measures of self-control.

Results

Self-control task performance was significantly impaired when exposed to smoking-related cues compared to neutral cues. No significant presentation-order effects, or interaction effects between stimulus and presentation order, were found.

Conclusions

Findings corroborate our hypothesis that resisting smoking urges depletes cigarette smokers’ self-control resources and suggests that self-control capacity is governed by a limited resource.     

Interaction between serum amyloid A and leukocytes - a possible role in the progression of vascular complications in diabetes

Diabetes mellitus is associated with an increased incidence of cardiovascular events and microvascular complications. Serum amyloid A (SAA), a HDL apolipoprotein is a risk marker for cardiovascular disease. A permanent increase in SAA plasma levels is observed in diabetics. Because SAA acts on leukocytes, we evaluated whether the synthesis of proinflammatory cytokines and migration of neutrophils and monocytes induced by SAA is affected in diabetics. Cells, isolated from human blood, were cultured in the presence of SAA. TNF-alpha, IL-1beta, IL-8 and IL-1ra levels were measured by ELISA in the culture supernatants and in serum of subjects. Neutrophils and monocytes migration were followed in a chemotaxis chamber. We make the novel observation that neutrophils and monocytes of diabetics are more responsive to SAA for the induction of the proinflammatory cytokine IL-1beta and the proangiogenic and chemotactic protein IL-8. Incremental TNF-alpha production was also found to occur when monocytes were stimulated with SAA. Cell migration was also increased. The increased production of cytokines and increased migration of leukocytes from diabetics in response to SAA may contribute to a sustained accumulation and activation of inflammatory cells in the disease. Accordingly, the hyper-responsiveness of leukocytes to SAA may be relevant to the proinflammatory conditions associated to vascular complications in diabetic patients.     

Professional burnout and work engagement among dentists

A recent development within burnout research is the shift to its conceptual opposite: work engagement. This study aimed to unravel the concepts of burnout and work engagement, and to determine their levels among dentists. A representative sample of 497 Dutch general dental practitioners was included (survey response rate of 59%), consisting of 372 men and 121 women (the gender of 4 dentists remained unknown). The hypothesized three-factor structure of work engagement (vigor, dedication, and absorption), as measured by the Utrecht Work Engagement Scale (UWES), was substantiated among dentists. It was also found that work engagement was related negatively to burnout, as measured by the Maslach Burnout Inventory (MBI). However, a model consisting of a reduced ('core') burnout factor and an 'enhanced' engagement factor (composed of the three original factors plus the burnout factor, personal accomplishment) showed the best fit. Overall burnout levels among dentists are low, and the levels of engagement indicate that dentists have a positive working attitude.