Staging of α‐synuclein in the olfactory bulb in a model of Parkinson's disease: Cell types involved

Impaired olfaction is an early symptom of Parkinson's disease. The underlying neuropathology likely includes α‐synucleinopathy in the olfactory bulb at an earlier stage (Braak's stage1) than pathology in the substantia nigra, which is not observed until stage 3. In this report, we investigated the distribution and cell types affected by α‐synuclein in the olfactory bulb of transgenic mice (2–8 months of age) expressing the human A53T variant of α‐synuclein. α‐Synuclein immunostaining progressively affects interneurons and mitral cells. Double labeling studies demonstrate that dopaminergic cells are hardly involved, whereas glutamatergic‐ and calcium binding protein‐positive cells are severely affected. This temporal evolution and the cell types expressing α‐synuclein are reminiscent of idiopathic Parkinson's disease and support the usefulness of this model to address specific topics in the premotor phase of the disease. © 2010 Movement Disorder Society     

Developing a methodology for assigning glycaemic index values to foods consumed across Europe

There is growing evidence that the glycaemic index (GI) of the diet is important with respect to body weight and metabolic disease risk. However, research is limited by the paucity of GI values for commonly consumed carbohydrate‐rich foods in European countries. A new methodology has been developed for consistent assignment of GI values to foods across five European databases used in the Diogenes intervention study. GI values were assigned according to five decreasing levels of confidence (1) Measured values for specific foods; (2) Published values from published sources; (3) Equivalent values where published values for similar foods existed; (4) Estimated values assigned as one of three values representing low/medium/high GI ranges and (5) Nominal values assigned as 70, where no other value could be assigned with sufficient confidence. GI values were assigned to 5105 foods. In food records collected at baseline, the contribution to carbohydrate intake of foods assigned levels 1–2 ranged from 16% to 43% depending on country, and this increased to 53–81% including level 3 foods. The degree of confidence to assigned GI values differed across Europe. This standardized approach of assigning GI values will be made available to other researchers to facilitate further investigation into the effects of dietary GI on health.     

Imaging pH and metastasis

Metastasis is a multistep process that culminates in the spread of cells from a primary tumor to a distant site or organs. For tumor cells to be able to metastasize, they have to locally invade through basement membrane into the lymphatic and the blood vasculatures. Eventually they extravasate from the blood and colonize in the secondary organ. This process involves multiple interactions between the tumor cells and their microenvironments. The microenvironment surrounding tumors has a significant impact on tumor development and progression. A key factor in the microenvironment is an acidic pH. The extracellular pH of solid tumors is more acidic in comparison to normal tissue as a consequence of high glycolysis and poor perfusion. It plays an important role in almost all steps of metastasis. The past decades have seen development of technologies to non-invasively measure intra- and/or extracellular pH. Most successful measurements are MR-based, and sensitivity and accuracy have dramatically improved. Quantitatively imaging the distribution of acidity helps us understand the role of the tumor microenvironment in cancer progression. The present review discusses different MR methods in measuring tumor pH along with emphasizing the importance of extracelluar tumor low pH on different steps of metastasis; more specifically focusing on epithelial-to-mesenchymal transition (EMT), and anti cancer immunity.     

Bulimia nervosa and evidence for striatal dopamine dysregulation: a conceptual review

Objective

This article reviews concepts and evidence, based in particular on the work of Bartley G. Hoebel and colleagues, which suggest that a better understanding of the role of striatal dopamine (DA) in the initiation and/or maintenance of bulimia nervosa (BN) may result in a clearer characterization of mechanisms underlying BN.

Methods

Literature review, using PubMed search.

Results

Several lines of evidence, including the work of Bartley G. Hoebel, implicate the importance of striatal DA in feeding behavior, as well as in the disordered eating behaviors relevant to BN. Preclinical models of ‘BN-like’ eating behaviors have been associated with changes in striatal DA and DA receptor measures. Emerging clinical research also suggests that striatal DA abnormalities exist in individuals with BN.

Conclusion

Alterations in striatal DA may exist in patients with BN. While the precise relationship between these findings and the etiology and maintenance of bulimic symptomatology remains unclear, further investigation of brain DA systems is a fruitful avenue of future research in BN.