Brain-derived neurotrophic factor (BDNF) is involved in synaptic plasticity, neuronal differentiation and survival of neurons. Observations of decreased serum BDNF levels in patients with neuropsychiatric disorders have highlighted the potential of BDNF as a biomarker, but so far there have been no studies directly comparing blood BDNF levels to brain BDNF levels in different species. We examined blood, serum, plasma and brain-tissue BDNF levels in three different mammalian species: rat, pig, and mouse, using an ELISA method. As a control, we included an analysis of blood and brain tissue from conditional BDNF knockout mice and their wild-type littermates. Whereas BDNF could readily be measured in rat blood, plasma and brain tissue, it was undetectable in mouse blood. In pigs, whole-blood levels of BDNF could not be measured with a commercially available ELISA kit, but pig plasma BDNF levels (mean 994±186 pg/ml) were comparable to previously reported values in humans. We demonstrated positive correlations between whole-blood BDNF levels and hippocampal BDNF levels in rats (r2=0.44, p=0.025) and between plasma BDNF and hippocampal BDNF in pigs (r2=0.41, p=0.025). Moreover, we found a significant positive correlation between frontal cortex and hippocampal BDNF levels in mice (r2=0.81, p=0.0139). Our data support the view that measures of blood and plasma BDNF levels reflect brain-tissue BDNF levels.

OBJECTIVETo describe the prevalence of biochemical B12 deficiency in adults with type 2 diabetes taking metformin compared with those not taking metformin and those without diabetes, and explore whether this relationship is modified by vitamin B12 supplements.RESEARCH DESIGN AND METHODSAnalysis of data on U.S. adults ≥50 years of age with (n = 1,621) or without type 2 diabetes (n = 6,867) from the National Health and Nutrition Examination Survey (NHANES), 1999–2006. Type 2 diabetes was defined as clinical diagnosis after age 30 without initiation of insulin therapy within 1 year. Those with diabetes were classified according to their current metformin use. Biochemical B12 deficiency was defined as serum B12 concentrations ≤148 pmol/L and borderline deficiency was defined as >148 to ≤221 pmol/L.RESULTSBiochemical B12 deficiency was present in 5.8% of those with diabetes using metformin compared with 2.4% of those not using metformin (P = 0.0026) and 3.3% of those without diabetes (P = 0.0002). Among those with diabetes, metformin use was associated with biochemical B12 deficiency (adjusted odds ratio 2.92; 95% CI 1.26–6.78). Consumption of any supplement containing B12 was not associated with a reduction in the prevalence of biochemical B12 deficiency among those with diabetes, whereas consumption of any supplement containing B12 was associated with a two-thirds reduction among those without diabetes.CONCLUSIONSMetformin therapy is associated with a higher prevalence of biochemical B12 deficiency. The amount of B12 recommended by the Institute of Medicine (IOM) (2.4 μg/day) and the amount available in general multivitamins (6 μg) may not be enough to correct this deficiency among those with diabetes.

We estimate an increasing prevention of FAPSBA in the world through folic acid fortification, yet the pace is slow. Our new model estimates that only 25% prevention and reminds us that there remains a lot of work to do in countries that do not implement mandatory fortification, which is key to achieving global and total prevention. If we are to prevent all FAPSBA, there is an urgent need to build the global political will to find sufficient resources to aid in this effort.

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Background The United States implemented mandatory folic acid fortification of enriched cereal grains in 1998. Although several studies have documented the resulting decrease in anemia and folate deficiency, to our knowledge, no one has determined the prevalence of folate-deficiency anemia after fortification. Objective We determined the prevalence of folate deficiency and folate-deficiency anemia within a sample of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. Design The REGARDS cohort is a prospective cohort of 30,239 black and white participants living in the contiguous United States. We measured serum folate concentrations in a random sample of 1546 REGARDS participants aged ≥50 y with baseline hemoglobin and red blood cell mean corpuscular volume measurements. Folate deficiency was defined as a serum folate concentration <6.6 nmol/L (<3.0 ng/mL), and anemia was defined as a hemoglobin concentration <13 g/dL in men and <12 g/dL in nonpregnant women (WHO criteria). Folate-deficiency anemia was defined as the presence of both folate deficiency and anemia. Results The mean hemoglobin concentration was 13.6 g/dL, and 15.9% of subjects had anemia. The median serum folate concentration was 34.2 nmol/L (15.1 ng/mL), and only 2 of 1546 participants 0.1%) were folate deficient. Both subjects were African American women with markedly elevated C-reactive protein concentrations, macrocytosis, and normal serum cobalamin concentrations; only one subject was anemic. Overall, the prevalence of folate-deficiency anemia was <0.1% (1 of 1546 subjects). Conclusion Our data suggest that, after mandatory folic acid fortification, the prevalence of folate-deficiency anemia is nearly nonexistent in a community-dwelling population in the United States.

J. Neurochem. (2011) 116, 1112–1121. Abstract Dendritic trafficking and translation of brain‐derived neurotrophic factor (BDNF) transcripts play a key role in mediating synaptic plasticity. Recently, we demonstrated that siRNA‐mediated knockdown of translin, an RNA‐binding protein, impairs KCl‐induced dendritic trafficking of BDNF mRNA in cultured hippocampal neurons. We have now assessed whether translin deletion impairs dendritic trafficking of BDNF mRNA in hippocampal neurons in vivo. We have found that translin and its partner protein, trax, undergo dendritic translocation in response to treatment with pilocarpine, a pro‐convulsant muscarinic agonist that increases dendritic trafficking of BDNF mRNA in hippocampal neurons. In translin knockout mice, the basal level of dendritic BDNF mRNA is decreased in CA1 pyramidal neurons. However, translin deletion does not block pilocarpine’s ability to increase dendritic trafficking of BDNF mRNA indicating that the requirement for translin in this process varies with the stimulus employed to drive it. Consistent with this inference, we found that dendritic trafficking of BDNF mRNA induced by bath application of recombinant BDNF in cultured hippocampal neurons, is not blocked by siRNA‐mediated knockdown of translin. Taken together, these in vivo and in vitro findings indicate that dendritic trafficking of BDNF mRNA can be mediated by both translin‐dependent and ‐independent mechanisms.

Most women of reproductive age who receive a valproate prescription do not have epilepsy. Valproate prescriptions did not decline, despite increasing knowledge of its teratogenicity. Reducing valproate use among women of reproductive age, especially among those who use the drug for psychiatric indications, would prevent birth defects and cognitive deficits.

Survivors of childhood cancer are at risk for a variety of treatment-related late effects and require lifelong individualized surveillance for early detection of late effects. This study assessed knowledge and perceptions of late effects risk before and after a survivor clinic visit. Young adult survivors (≥ 16 years) and parents of child survivors (< 16 years) were recruited prior to initial visit to a cancer survivor program. Sixty-five participants completed a baseline survey and 50 completed both a baseline and follow-up survey. Participants were found to have a low perceived likelihood of developing a late effect of cancer therapy and many incorrect perceptions of risk for individual late effects. Low knowledge before clinic (odds ratio = 9.6; 95% confidence interval, 1.7-92.8; P = .02) and low perceived likelihood of developing a late effect (odds ratio = 18.7; 95% confidence interval, 2.7-242.3; P = .01) were found to predict low knowledge of late effect risk at follow-up. This suggests that perceived likelihood of developing a late effect is an important factor in the individuals' ability to learn about their risk and should be addressed before initiation of education.