Understanding urbanicity: how interdisciplinary methods help to unravel the effects of the city on mental health

Twenty-first century urbanization poses increasing challenges for mental health. Epidemiological studies have shown that mental health problems often accumulate in urban areas, compared to rural areas, and suggested possible underlying causes associated with the social and physical urban environments. Emerging work indicates complex urban effects that depend on many individual and contextual factors at neighbourhood and country level and novel experimental work is starting to dissect potential underlying mechanisms. This review summarizes findings from epidemiology and population- based studies, neuroscience, experimental, and experience-based research and illustrates how a combined approach can move the field towards an increased understanding of the urbanicity-mental health nexus

Differential expression of neurotrophin receptors during renal development

Early kidney differentiation is driven by local cell-cell interactions. The metanephrogenic mesenchyme stimulates the epithelial ureter bud to grow and branch, whereas the ureter bud stimulates the mesenchyme to convert into a new epithelium. These interactions may be dependent on local growth factors and their receptors. We studied the expression of receptors for nerve growth factors during kidney development. Expression of the low- and high-affinity receptors was cell-type specific. The low-affinity NGF receptor was found in the uninduced mesenchyme at early developmental stages, but in the glomerular podocytes at later developmental stages. In contrast, the high-affinity trkB receptor was found in the cortical mesenchyme cells that will differentiate into stroma. The trkC receptor was found only weakly expressed and in a few parts of the collecting ducts. The role of these receptors and c-ros, a receptor-type kinase expressed on the tip of the ureter bud, was studied by modified antisense oligonucleotides. However, we found that both sense, antisense and nonsense phosphorothioate oligonucleotides inhibited mouse and rat embryonic kidney development in vitro. The oligonucleotides appeared to be toxic for rodent embryonic kidneys in the experimental conditions that we used. Moreover, oligonucleotides did not penetrate well into the epithelial sheets in the organ cultures. We conclude that studies with phosphorothioate antisense oligonucleotides in organ cultures of embryonic kidneys should be interpreted with caution. Our current data do not allow us to not assign a function for the low- or high-affinity NGF receptors or c-ros in kidney development