Stress-Induced Cortisol,Mood, and Fat Distribution in Men

EPEL, ELISSA A., ANNE E. MOYER, CHLOE D. MARTIN, SUSAN MACARY, NANCY CUMMINGS, JUDITH RODIN, AND MARIELLE REBUFFE-SCRIVE. Stress-induced Cortisol, mood, and fat distribution in men. Obes Res. 1999;7:9–15. Objective : A previous study in our laboratory (Moyer et al., Obes Res. 1994;2:255-62 found that, in response to uncontrollable laboratory stress, women with a high waist-to-hip ratio (WHR) had higher Cortisol reactivity, poorer coping skills, and lower anger responses than women with low WHR. We aimed to compare high WHR men's stress responses to these women. Research Methods and Procedures : The current study examined Cortisol reactivity and psychological data of 27 healthy high WHR men exposed to the same laboratory challenges as the women from our previous study. Men's data are discussed in relation to that of the high and low WHR women. Results : Men responded to the stress with increases in both Cortisol and blood pressure. In comparison with the high and low WHR women, men had significantly higher total cortisof on the stress day. However, when comparing a sub-sample of men and women matched in WHR's, differences in Cortisol secretion were greatly diminished and no longer significant. In addition, men had higher desire for control than both high and low WHR women, and lower mood reactivity than low WHR women. Despite the lower mood reactivity of high WHR groups, the high mood reactors among the high WHR women, and to a lesser extent, men, tended to have higher Cortisol reactivity. Discussion: These results suggest that the psychological differences and greater exposure to Cortisol observed amon; the high WHR men and women may have played a role ii contributing to their greater abdominal fat depots. Discussion : These results suggest that the psychological differences and greater exposure to cortisol observed among the high WHR men and women may have played a role contributing to their greater abdominal fat depots.     

A mechanistic analysis of light and carbon use efficiencies

We explore the extent to which a simple mechanistic model of short-term plant carbon (C) dynamics can account for a number of generally observed plant phenomena. For an individual, fully expanded leaf, the model predicts that the fast-turnover labile C, starch and protein pools are driven into an approximate or moving steady state that is proportional to the average leaf absorbed irradiance on a time-scale of days to weeks, even under realistic variable light conditions, in qualitative agreement with general patterns of leaf acclimation to light observed both temporally within the growing season and spatially within plant canopies. When the fast-turnover pools throughout the whole plant (including stems and roots) also follow this moving steady state, the model predicts that the time-averaged whole-plant net primary productivity is proportional to the time-averaged canopy absorbed irradiance and to gross canopy photosynthesis, and thus suggests a mechanistic explanation of the observed approximate constancy of plant light-use efficiency (LUE) and carbon-use efficiency. Under variable light conditions, the fast-turnover pool sizes and the LUE are predicted to depend negatively on the coefficient of variation of irradiance. We also show that the LUE has a maximum with respect to the fraction of leaf labile C allocated to leaf protein synthesis ( a_lp ), reflecting a trade-off between leaf photosynthesis and leaf respiration. The optimal value of a_lp is predicted to decrease at elevated [CO₂] _a , suggesting an adaptive interpretation of leaf acclimation to CO₂. The model therefore brings together a number of empirical observations within a common mechanistic framework.     

Structural Basis for Recognition of a Unique Epitope by a Human Anti-tau Antibody

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The Neuronal Gene Arc Encodes a Repurposed Retrotransposon Gag Protein that Mediates Intercellular RNA Transfer

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Xenopsylla cheopis (Siphonaptera: Pulicidae) Susceptibility to Deltamethrin in Madagascar

The incidence of bubonic plague in Madagascar is high. This study reports the susceptibility of 32 different populations of a vector, the flea Xenopsylla cheopis (Siphonaptera: Pulicidae), to the insecticide Deltamethrin. Despite the use of Deltamethrin against fleas, plague epidemics have re-emerged in Madagascar. The majority of the study sites were located in the Malagasy highlands where most plague cases have occurred over the last 10 years. X. cheopis fleas were tested for susceptibility to Deltamethrin (0.05%): only two populations were susceptible to Deltamethrin, four populations were tolerant and 26 populations were resistant. KD50 (50% Knock-Down) and KD90 (90% Knock-Down) times were determined, and differed substantially from 9.4 to 592.4 minutes for KD50 and 10.4 min to 854.3 minutes for KD90. Susceptibility was correlated with latitude, but not with longitude, history of insecticide use nor date of sampling. Combined with the number of bubonic plague cases, our results suggest that an immediate switch to an insecticide other than Deltamethrin is required for plague vector control in Madagascar.     

Effects of elevated [CO2] on forest growth and carbon storage: a modelling analysis of the consequences of changes in litter quality/quantity and root exudation

Many researchers have proposed that the stimulus of plant growth under elevated [CO₂] observed in short-term experiments will be moderated in the longer term by a reduction in soil nitrogen (N) availability linked to decreased litter quality and/or increased litter production. However, these negative feedbacks may be offset to some extent by a stimulus in N fixation linked to increased root exudation. The aim of this modelling study is to examine how changes in litter quality/quantity and root exudation –- if they occur –- will affect the CO₂ responses of net primary productivity and ecosystem carbon (C) storage on different timescales. We apply a model of C and N cycling in forest ecosystems (G’DAY) to stands of Norway spruce (Picea abies, L. Cast) growing at a N-limited experimental site at Flakaliden, Sweden, and draw the following conclusions: (1) in the absence of changes in litter quality and root exudation, the short-term CO₂ stimulus of litter quantity leads to only a minimal CO₂ stimulus of productivity or C storage in the medium term (≈ 20 years) and long term (≈ 200 years), because of constraints on soil N availability; (2) increasing plant nitrogen use efficiency (via a decrease in the N:C ratio of new litter) makes little impact on these results; (3) a significant CO₂ response in the medium term requires a substantial decrease in the N:C ratio of older litter, when it is approaching stabilisation as soil organic matter, although the long-term CO₂ response remains small; and (4) an increase in N fixation leads to a small effect on productivity in the short term, but a very large effect on both productivity and C storage in the long term. These results suggest that soil N constraints on the long-term CO₂-fertilisation effect can be overcome to a significant extent only by increases in N acquisition, although only modest increases may be required. This revised version was published online in June 2006 with corrections to the Cover Date.     

Genetic Regulation of Zfp30, CXCL1, and Neutrophilic Inflammation in Murine Lung

Allergic asthma is a complex disease characterized in part by granulocytic inflammation of the airways. In addition to eosinophils, neutrophils (PMN) are also present, particularly in cases of severe asthma. We sought to identify the genetic determinants of neutrophilic inflammation in a mouse model of house dust mite (HDM)-induced asthma. We applied an HDM model of allergic asthma to the eight founder strains of the Collaborative Cross (CC) and 151 incipient lines of the CC (preCC). Lung lavage fluid was analyzed for PMN count and the concentration of CXCL1, a hallmark PMN chemokine. PMN and CXCL1 were strongly correlated in preCC mice. We used quantitative trait locus (QTL) mapping to identify three variants affecting PMN, one of which colocalized with a QTL for CXCL1 on chromosome (Chr) 7. We used lung eQTL data to implicate a variant in the gene Zfp30 in the CXCL1/PMN response. This genetic variant regulates both CXCL1 and PMN by altering Zfp30 expression, and we model the relationships between the QTL and these three endophenotypes. We show that Zfp30 is expressed in airway epithelia in the normal mouse lung and that altering Zfp30 expression in vitro affects CXCL1 responses to an immune stimulus. Our results provide strong evidence that Zfp30 is a novel regulator of neutrophilic airway inflammation.