Nonesterified Fatty Acids and Depression in Cancer Patients and Caregivers.

BACKGROUND: Nonesterified fatty acids (NEFAs) are known to have inflammatory effects. The inflammatory hypothesis of depression suggests that omega-3 (ω-3) and omega-6 (ω-6) fatty acids might be negatively and positively correlated with depression, respectively. OBJECTIVE: An exploratory study was conducted to determine the association between dietary free fatty acids and depressive symptoms in cancer patients and caregivers. METHODS: Associations between depression and the NEFA pool were investigated in 56 cancer patients and 23 caregivers using a combination of nonparametric tests and regularized regression. Plasma NEFAs were measured using thin layer and gas chromatography with flame ionization detection. Depression was characterized both as a continuous severity score using the GRID-Hamilton Depression Rating Scale (GRID Ham-D), and as a categorical diagnosis of major depression by structured clinical interview. RESULTS: Initial hypotheses regarding the relation between depression and omega-3 or omega-6 fatty acids were not well supported. However, elaidic acid, a trans-unsaturated fatty acid found in hydrogenated vegetable oils, was found to be negatively correlated with continuous depression scores in cancer patients. No significant associations were found in caregivers. CONCLUSIONS: An unexpected negative association between elaidic acid and depression was identified, supporting recent literature on the role of G protein-coupled receptors in depression. Further research is needed to confirm this result and to evaluate the potential role of G protein agonists as therapeutic agents for depression in cancer patients.

Positive relationships between genetic diversity and abundance in fishes.

Molecular markers, such as mitochondrial DNA and microsatellite loci, are widely studied to assess population genetics and phylogeography; however, the selective neutrality of these markers is increasingly being questioned. Given the importance of molecular markers in fisheries science and conservation, we evaluated the neutrality of both mtDNA and microsatellite loci through their associations with population size. We surveyed mtDNA and microsatellite data from the primary literature and determined whether genetic diversity increased with abundance across a total of 105 marine and freshwater fishes, with both global fisheries catch data and body size as proxies for abundance (with an additional 57 species for which only body size data were assessed). We found that microsatellite data generally yielded higher associations with abundance than mtDNA data, and within mtDNA analyses, number of haplotypes and haplotype diversity were more strongly associated with abundance than nucleotide diversity, particularly for freshwater fishes. We compared genetic diversity between freshwater and marine fishes and found that marine fishes had higher values of all measures of genetic diversity than freshwater fishes. Results for both mtDNA and microsatellites generally conformed to neutral expectations, although weaker relationships were often found between mtDNA nucleotide diversity and 'abundance' compared to any other genetic statistic. We speculate that this is because of historical events unrelated to natural selection, although a role for selection cannot be ruled out.

Historical influences dominate the population genetic structure of a sedentary marine fish, Atlantic wolffish (Anarhichas lupus), across the North Atlantic Ocean.

Genetic variation was assessed in Atlantic wolffish, Anarhichas lupus, across the North Atlantic Ocean using microsatellite and amplified fragment length polymorphism (AFLP) markers. Despite unusual life history attributes such as large benthic eggs, large larvae, a limited pelagic stage and relatively sedentary adults, which suggest potential for strong population structure, range-wide FST values were comparable to other marine fishes (≤0.035). Nevertheless, both significant genetic differentiation among regions and isolation by distance were observed, suggesting limited dispersal in this species. AFLP loci, evaluated on a subset of samples, revealed slightly higher FST values, but similar patterns of differentiation and isolation-by-distance estimates, compared to microsatellites. The genetic structure of Atlantic wolffish has likely been shaped by its post-glacial history of recolonization, North Atlantic current patterns and continuity of habitat on continental shelves.

Phylogeography of 3 North Atlantic Wolffish species (Anarhichas spp.) with phylogenetic relationships within the family Anarhichadidae.

Phylogenetic analyses of all 4 wolffish species (Atlantic, Spotted, Northern, and Bering wolffishes) and the Wolfeel were assessed with both mitochondrial (D-loop and ND1) and nuclear (amplified fragment length polymorphism) DNA to resolve relationships within the family Anarhichadidae. Species-specific mitochondrial DNA (mtDNA) mutation rates were estimated based on 2 possible dates of divergence between the Pacific and Atlantic lineages. Phylogeographic patterns within each of the 3 North Atlantic wolffishes were investigated with Markov chain Monte Carlo simulations based on mtDNA to determine whether population size changes occurred following the last glaciation and where wolffishes likely survived glaciation. All 3 species of North Atlantic wolffishes showed evidence of postglacial expansion but did not show evidence of persistence in multiple refugia in both the eastern and western Atlantic Ocean. Rather, the data supported persistence in a single refuge, with postglacial expansion into the rest of the range. Nucleotide diversity, in particular, was low in wolffishes compared with other marine fishes, possibly related to reductions in population sizes during the last glaciation.