Circulating insulin-like growth factor I modulates mood and is a biomarker of vulnerability to stress:from mouse to man

Individual susceptibility to anxiety disorders after maladaptive responses to stress is not well understood. We now report that while exploring stress responses in mice after traumatic brain injury (TBI), a condition associated to stress susceptibility, we observed that the anxiogenic effects of either TBI or exposure to life-threatening experiences (predator) were blocked when both stressors were combined. Because TBI increases the entrance into the brain of serum insulin-like growth factor I (IGF-I), a known modulator of anxiety with a wide range of concentrations in the human population, we then determined whether circulating IGF-I is related to anxiety measures. In mice, anxiety-like responses to predator were inversely related to circulating IGF-I levels. Other indicators of mood regulation such as sensitivity to dexamethasone suppression and expression levels of blood and brain FK506 binding protein 5 (FKBP5), a co-chaperone of the glucocorticoid receptor that regulates its activity, were also associated to circulating IGF-I. Indeed, brain FKBP5 expression in mice was stimulated by IGF-I. In addition, we observed in a large human cohort (n = 2686) a significant relationship between plasma IGF-I and exposure to recent stressful life events, while FKBP5 expression in blood cells was significantly associated to plasma IGF-I levels. Collectively, these data indicate that circulating IGF-I appears to be involved in mood homeostasis across different species. Furthermore, the data in mice allow us to indicate that IGF-I may be acting at least in part by modulating FKBP5 expression

Using network analysis to examine links between individual depressive symptoms, inflammatory markers, and covariates

Background   Studies investigating the link between depressive symptoms and inflammation have yielded inconsistent results, which may be due to two factors. First, studies differed regarding the specific inflammatory markers studied and covariates accounted for. Second, specific depressive symptoms may be differentially related to inflammation. We address both challenges using network psychometrics.   Methods   We estimated seven regularized Mixed Graphical Models in the Netherlands Study of Depression and Anxiety (NESDA) data (N = 2321) to explore shared variances among (1) depression severity, modeled via depression sum-score, nine DSM-5 symptoms, or 28 individual depressive symptoms; (2) inflammatory markers C-reactive protein (CRP), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α); (3) before and after adjusting for sex, age, body mass index (BMI), exercise, smoking, alcohol, and chronic diseases.   Results   The depression sum-score was related to both IL-6 and CRP before, and only to IL-6 after covariate adjustment. When modeling the DSM-5 symptoms and CRP in a conceptual replication of Jokela et al., CRP was associated with ‘sleep problems’, ‘energy level’, and ‘weight/appetite changes’; only the first two links survived covariate adjustment. In a conservative model with all 38 variables, symptoms and markers were unrelated. Following recent psychometric work, we re-estimated the full model without regularization: the depressive symptoms ‘insomnia’, ‘hypersomnia’, and ‘aches and pain’ showed unique positive relations to all inflammatory markers.   Conclusions   We found evidence for differential relations between markers, depressive symptoms, and covariates. Associations between symptoms and markers were attenuated after covariate adjustment; BMI and sex consistently showed strong relations with inflammatory markers

Chronotype, daily affect and social contact:An ecological momentary assessment study

Eveningness is associated with lower daily positive affect (PA). The relationship between negative affect (NA) and chronotype, however, is less consistent in the literature. Eveningness may be further characterized by increased social isolation, which could explain the associations between chronotype and PA/NA. In the present longitudinal study, we used ecological momentary assessment (EMA) to investigate the associations of chronotype with daily PA, NA, and social contact in individuals with current and remitted major depressive disorder (MDD) and healthy controls. As part of the Netherlands Study of Depression and Anxiety (NESDA), 279 participants (n = 49 depressed, n = 172 remitted, n = 58 controls) monitored daily PA, NA, and social contact (i.e., being alone vs. with others) for two weeks, five times per day. Overall, eveningness was associated with less social contact. This effect became nonsignificant, however, after accounting for sociodemographics (gender, age, education, living situation). Chronotype was not related to PA or NA. Less social contact was associated with lower PA and higher NA independent of chronotype. In conclusion, we could not replicate the finding of lower PA among evening types, but found social contact to associate with both daily PA and NA

Chronotype changes with age; seven-year follow-up from the Netherlands study of depression and anxiety cohort

Background: Chronotype reflects an individual's optimal daily timing of sleep, activity, and cognitive performance. Previous, cross-sectional, studies have suggested an age effect on chronotype with later chronotypes in adolescents and earlier chronotypes in children and elderly. Additionally, later chronotypes have been associated with more depressive symptoms. Few studies have been able to study longitudinal associations between chronotype and age, while adjusting for depressive symptoms. Methods: Chronotype was assessed twice with the Munich Chronotype Questionnaire 7 years apart in the Netherlands Study of Depression and Anxiety (T1: N = 1842, mean age (SD): 42.63 years (12.66)) and T2: N = 1829, mean age (SD) 50.67 (13.11)). The longitudinal association between change in age and change in chronotype was tested using a generalized estimated equation analysis adjusted for covariates (including level of depressive symptoms). Using age-bins of 5 years (age at T2), change in chronotype between T1 and T2 was analyzed with Linear Mixed Models. Results: We found a change towards an earlier chronotype with higher age (B (95% CI): -0.011 (-0.014-0.008), p < 0.001). For the age-bins, the difference in chronotype was significant for the 25-29 years age-bin. Limitations: The sample did not include individuals younger than 19 years or older than 68 years. Conclusions: In the whole sample chronotype changed towards becoming more morning-type over a period of 7 years, but this change was only significant for those aged 25-29 years. The study was performed in a large naturalistic cohort study with a wide age-range, including patients with a diagnosis of depressive and anxiety disorder and healthy controls.Stress and Psychopatholog

New Results for Two Optically Faint Low Mass X-Ray Binary Systems

We present optical photometry of the low mass X-ray binary systems GX 349+2 and Ser X-1. Extensive VRI photometry of the faint optical counterpart (V=18.4) to GX 349+2 reveals a period of 22.5 +/- 0.1 h and half-amplitude 0.2 mag. This result confirms and extends our previously reported 22 h period. No color change is detected over the orbit, although the limits are modest. We also report the discovery of two new variable stars in the field of GX 349+2, including a probable W UMa system. Ser X-1 is one of the most intense persistent X-ray burst sources known. It is also one of only three burst systems for which simultaneous optical and X-ray bursts have been observed. The faint blue optical counterpart MM Ser (B~19.2) has long been known to have a companion 2.1" distant. Our images indicate that MM Ser is itself a further superposition of two stars, separated by only 1". At the very least, the ratio of inferred burst to quiescent optical flux is affected by the discovery of this additional component. In the worst case, the wrong object may have previously been assumed as the optical counterpart.Comment: 16 pages including 10 figures and 3 tables; Uses AASTeX 4.0; Accepted for publication in The Astrophysical Journal, Volume 490, November 20, 199

Disappearance of Hard X-ray Emission in the Last BeppoSAX Observation of the Z Source GX 349+2

We report on the results from two BeppoSAX observations of the Z source GX 349+2 performed in February 2001 and covering the broad energy range 0.12-200 keV. The light curve obtained from these observations shows a large flaring activity, the count rate varying from ~130 to ~260 counts/s, indicating that the source was in the flaring branch during these observations. The average spectrum is well described by a soft blackbody and a Comptonized component. To well fit the energy spectrum three gaussian lines are needed at 1.2 keV, 2.6 keV, and 6.7 keV with corresponding equivalent widths of 13 eV, 10 eV, and 39 eV, probably associated to L-shell emission of Fe XXIV, Ly-alpha S XVI, and Fe XXV, respectively. These lines may be produced at different distances from the neutron star, which increase when the count rate of the source increases. An absorption edge is also needed at 9 keV with an optical depth of ~3 10^{-2}. From the Color-Color Diagram (CD) we selected five zones from which we extracted the corresponding energy spectra. The temperatures of the blackbody and of the Comptonized component tend to increase when the intensity of the source increases. We discuss our results comparing them to those obtained from a previous BeppoSAX observation, performed in March 2000, during which the source was a similar position of its Z-track. In particular we find that, although the source showed similar spectral states in the 2000 and the 2001 observations, a hard tail, that was significantly detected in March 2000, is not observed in these recent observations.Comment: Accepted for publication on Ap

Levenswaardering bij ouderen (LWO): de validering van een meetinstrument

De doelstelling van dit onderzoek is de aanpassing en validering van een door Lawton en collega’s ontwikkelde schaal “Valuation of Life”, door ons vertaald als Levenswaardering. Lawton et al. ontwikkelden deze schaal om te laten zien dat naast de gezondheidsgerelateerde kwaliteit-van-leven (GKvL) er een andere kwaliteitsdimensie is die inzicht kan verschaffen in de subjectieve gezondheidsutiliteit op latere leeftijd, waaronder opvattingen over de gewenste levensduur en/of over levensverlenging en –beëindiging. Na een geautoriseerde vertaling is de schaal geïmplementeerd in de vierde waarneming van de LASA studie (2001-2002). In totaal hebben 1139 respondenten van 65-95 jaar de schaal ingevuld. Uitgebreide structuuranalyses leidden tot de conclusie dat de oorspronkelijke 19-item schaal tot een schaal van Levenswaarderingbij- Ouderen van 12 items kan worden gereduceerd, welke op te delen valt in drie subschalen: Veerkracht, Ambitie en Levenslust. Er blijkt nauwelijks overlap te zijn met de GKvL terwijl de overlap met min of meer objectieve gezondheidsmaten (discriminante validiteit) beperkt blijft. Er blijkt wel een verwantschap met de zg. positieve zelfbelevingsmaten (concurrente validiteit). We concluderen dan ook dat de LWO-schaal de waardering meet die iemand aan het leven hecht, waarbij er in de schaal-items geen enkele expliciete verwijzing is naar gezondheidsaspecten. De uiteindelijke toets voor het belang van de LWO-schaal zal moeten blijken in de onafhankelijke voorspellende kracht van de gezondheidsutiliteit die in een volgend artikel nader onderzocht gaat worden