The chronic psychosocial stress paradigm in male tree shrews: evaluation of a novel animal model for depressive disorders

To improve our knowledge of the causal mechanisms of stress-related disorders such as depression, we need animal models that mirror the situation in patients. One promising model is the chronic psychosocial stress paradigm in male tree shrews, which is based on the territorial behaviour of these animals that can be used to establish naturally occurring challenging situations under experimental control in the laboratory. Co-existence of two males in visual and olfactory contact leads to a stable dominant-subordinate relationship, with subordinates showing distinct stress-induced behavioural and neuroendocrine alterations that are comparable to the symptoms observed during episodes of depression in patients such as constantly elevated circulating glucocorticoid hormones due to a chronic hyperactivity of the hypothalamic-pituitary-adrenal axis. To elucidate whether the chronic psychosocial stress model in tree shrews besides its "face validity" for depression also has "predictive validity", we treated subordinate tree shrews with the tricyclic antidepressant clomipramine and found a time-dependent restoration of both endocrine and behavioural parameters. In contrast, the anxiolytic diazepam was ineffective. Although the chronic psychosocial stress model in tree shrews requires further validation, it has sufficient face, predictive, and construct validity to become an interesting non-rodent model for research on the etiology and pathophysiology of depression.     

Galectin-3 decreases in mice exposed to immobilization stress

Using M3/38 monoclonal antibody we have analyzed effects of immobilization stress on the expression of galectin-3 in liver, spleen and peritoneal macrophages from adult RFM and C3H mice, as well as from aged C3H mice (total of 22 animals). In all analyzed tissues, immobilization stress caused a significant decrease in the expression of galectin-3, ranging from 14% to 47%. The decrease of galectin-3 was observed in both strains of mice, as well as in old animals. Moreover, the same range of decrease (approximately 50%) was observed when cells grown in vitro were exposed to subculturing, or heat-shock. Although the biological significance of this effect is not known, it is very interesting that a single episode of immobilization stress was sufficient to cause a significant decrease in galectin-3, implicating that this beta-galactoside-binding lectin might be involved in the physiological response to psychological stress.     

Quality of life and depression in haemodialysis patients

Chronic kidney disease is associated with a high prevalence of depression, which increases inversely with the glomerular filtration rate. This paper aims to evaluate the factors associated with a low quality of life and depression in patients on haemodialysis. Two hundred patients undergoing haemodialysis answered the Medical Outcomes Study 36 – Item Short – Form Health Survey (SF-36) and Beck Depression Inventory (BDI). Clinical and laboratory variables were analysed and correlated with these two tools. The prevalence of depression was 29%. Anaemia and hypoalbuminemia were independent risk factors for depression. All SF-36 domains showed worse results in patients with depression, and the pain domain presented the highest correlation. Our findings provide evidence that patients on haemodialysis have a low quality of life and a high prevalence of depression. A greater number of comorbidities, an excessive number of medications, diabetes mellitus, anaemia and hypoalbuminemia were associated with a reduced quality of life.     

Homophobia as a Boundary Phenomenon: The Dynamic Dance Between Different Tensions

From the commentaries presented in this issue, the main goal of this reply is to improve the analysis of homophobia as a boundary phenomenon of affective meaning-making, a collective historical–cultural construction. According to dialectical philosophical tradition, the notion of tension of opposites united within the same whole is a central notion that assumes an important role in the studies of meaning-making processes (Josephs and Valsiner, Social Psychology Quarterly, 61(1):68–83, 1998). Therefore, this paper intends to analyze homophobia issues from the dynamic dance between different tensions: (a) the tension between the general and the particular; (b) the tension between the HEIMWEH and the FERNWEH processes; and (c) the tension between stability and change. Presented in the conclusion are some suggestions for future approaches about homophobia that could be advanced within the general area of cultural psychology.