Eicosanoid synthesis in 7,12-dimethylbenz(a)anthracene-induced mammary carcinomas in Sprague-Dawley rats fed primrose oil,menhaden oil or corn oil diet

The comparative effects of high-fat diets (20%, w/w) on eicosanoid synthesis during mammary tumor promotion in 7,12-dimethylbenz(a)anthracene (DMBA)-induced rats were studied using diets containing 20% primrose oil (PO), 20% menhaden oil (MO) or 20% corn oil (CO). Sprague-Dawley rats fed the PO or MO diet had 21% or 24% fewer adenocarcinomas, respectively, than rats fed the CO diet. Histologically (i.e., mitotic figures, inflammatory cell infiltration and necrosis), the CO-fed rats exhibited the highest frequency of changes within tumors. Plasma fatty acid composition was significantly altered by diet, reflecting the composition of the oils which were being fed. Only the plasma of PO-fed rats contained detectable levels of gamma-linolenic acid (GLA). Arachidonic acid (AA) levels were significantly higher (p<0.05) in PO-fed than in CO- or MO-fed rats. MO-fed rats had significantly higher levels of plasma palmitic acid, while palmitoleic, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids were detected only in MO-fed rats. As expected, linoleic acid (LA) and AA levels were lower (p<0.05) in the MO-fed rats than in PO- or CO-fed groups. The plasma of the CO-fed rats contained significantly higher levels of oleic acid. Eicosanoid synthesis in mammary carcinomas of rats fed the 20%-fat diets was 2–10 times higher than in mammary fat pads of control rats. The synthesis of PGE₁ and LTB₄ was significantly (p<0.05) higher in PO-fed rats than in CO-fed or MO-fed rats, although PGE values were significantly (p<0.05) higher in CO-fed rats than in Mo or PO groups. The synthesis of eicosanoids in both mammary fat pads and mammary carcinomas of MO-fed rats was lower (p<0.05) than in tissues of rats fed either CO or PO diets due to less AA precursor being fed and/or to competition between n−6 and n−3 fatty acids for cyclooxygenase and lipoxygenase. The ratios of monoenoic to dienoic eicosanoids in both mammary fat pads and mammary carcinomas were higher in the PO group than in the MO or CO groups. These results suggest that inclusion of GLA (PO feeding) or EPA and DHA (MO feeding) in the diet may decrease malignancy by altering eicosanoid profiles.     

Graphite: An active or an inactive anode?

Positive polarization of a graphite anode in aqueous solution functionalizes the surface and releases soluble organic carbon to the solution concurrent with the electrolysis of water. Mineralization of the anode occurs at more positive potentials, and can be explained as a repetitive sequence involving functionalization, oxidation to carboxyl, and Kolbe decarboxylation, without recourse to hydroxyl radicals. Other lines of evidence against the intermediacy of hydroxyl radicals include the resistance of p-benzoquinone towards oxidation at graphite – i.e., graphite does not function as an inactive anode towards the oxidation of added substrates. A direct electron transfer mechanism operates for substrates that are oxidizable in the range of water stability, such as acetaminophen and sulfide ion. In the potential range of oxygen evolution we propose that graphite behaves as a modified active anode, at which the oxygen atom to be transferred to an oxidizable substrate first becomes bonded to the previously functionalized surface.     

Cognitive support at encoding attenuates age differences in recollective experience among adults of lower frontal lobe function.

Free recall and recollective experience were investigated in relation to low and high cognitive support at encoding and to neuropsychological measures of frontal lobe function (FLF) in 105 healthy adults divided into 3 age groups (young, young-old, old). Statistically significant main effects suggested free recall was inferior with increasing age and lower FLF. For recollective experience however, a significant interaction between age and FLF was modified by the provision of cognitive support at encoding. Recognition measures classified as familiar did not vary according to age, neuropsychological function, or encoding condition. The results suggest that the neural systems of the prefrontal cortex underlie age differences in recollective experience and that cognitive support modifies the influence of those systems in old age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Growth of single HL60 cells in liquid culture: analysis of the influences of differentiative agents

Treatment of serum-free grown HL60 cells with certain combined amounts of retinoic acid (9-cis or all-trans RA) and 1 alpha 25 dihydroxyvitamin D3 (D3) results in differentiation of 71-77% of cells towards either neutrophils or monocytes. Studies of the differentiation of HL60 cells in flask cultures does not reveal: (i) the extent to which selective growth of cells might have occurred; and (ii) the overall level of cell survival. This information can be obtained by monitoring the effects of differentiative agents on individual cells. Serum-free grown HL60 cells were cultured as single cells in microtitre wells in conditioned medium obtained from exponentially growing and serum-free cultures of HL60. This resulted in a cloning efficiency of 85% and HL60 cells doubled every 24 h. During a period of exponential growth < 0.5 to 2% of the cells generated died. Single HL60 cells were treated with 9-cis and all-trans RA (5 x 10(-7) M) together with a small amount of D3 (3.9 x 10(-14) M) to promote neutrophil differentiation. D3 alone (10(-7) M) and D3 (5 x 10(-9) M) in combination with 9-cis RA (10(-8) M) were used to promote monocyte differentiation. The growth kinetics of HL60 cell cultures that were differentiating to neutrophils and to monocytes were similar. Single-cell experiments have revealed that: (i) differentiating HL60 cells undergo a variable number of divisions (two to five) prior to arresting their growth; and (ii) up to 33% of the cells that are generated (by day 5) die. Seventy to eighty per cent of the cells in each of the wells had matured. These findings have important implications in regard to whether retinoids and D3 provide signals that determine the choice of maturation pathway or that merely facilitate selective survival and/or expansion of cells that have independently determined their differentiation fates.     

The influence of psychological flexibility on work redesign: Mediated moderation of a work reorganization intervention.

This quasi-experiment tested the extent to which an individual characteristic, psychological flexibility, moderated the effects of a control-enhancing work reorganization intervention in a call center. Results indicated that, compared with a control group, this intervention produced improvements in mental health and absence rates, particularly for individuals with higher levels of psychological flexibility. Findings also showed that these moderated intervention effects were mediated by job control. Specifically, the intervention enhanced perceptions of job control, and hence its outcomes, for the people who received it, especially for those who had greater psychological flexibility. Discussion highlights the benefits of understanding the processes (e.g., mediators, moderators, and mediated moderators) involved in work reorganization interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Utilization of Cognitive Support in Episodic Free Recall as a Function of Apolipoprotein E and Vitamin B?? or Folate Among Adults Aged 75 Years and Older.

Apolipoprotein E (APOE), vitamin B??, and folate were examined in relation to free recall among 167 community-based older adults. Cognitive support at encoding and retrieval was also taken into account. Participants were classified as APOE e4 or non-e4 allele carriers and as either low or normal vitamin B?? or folate status. A significant association was identified between low vitamin B?? and the e4 genotype in respect to free recall, but only in circumstances of low cognitive support. This result remained after removing dementia cases that occurred up to 6 years after testing. A similar, but nonsignificant, trend was evident in relation to folate. The research is discussed with reference to vulnerability models and genetic influences on brain reserves. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inhibition of Bacterial Dihydrofolate Reductase by 6‐Alkyl‐2,4‐diaminopyrimidines

(±)‐6‐Alkyl‐2,4‐diaminopyrimidine‐based inhibitors of bacterial dihydrofolate reductase (DHFR) have been prepared and evaluated for biological potency against Bacillus anthracis and Staphylococcus aureus. Biological studies revealed attenuated activity relative to earlier structures lacking substitution at C6 of the diaminopyrimidine moiety, though minimum inhibitory concentration (MIC) values are in the 0.125–8 μg mL^?1 range for both organisms. This effect was rationalized from three‐ dimensional X‐ray structure studies that indicate the presence of a side pocket containing two water molecules adjacent to the main binding pocket. Because of the hydrophobic nature of the substitutions at C6, the main interactions are with protein residues Leu 20 and Leu 28. These interactions lead to a minor conformational change in the protein, which opens the pocket containing these water molecules such that it becomes continuous with the main binding pocket. These water molecules are reported to play a critical role in the catalytic reaction, highlighting a new area for inhibitor expansion within the limited architectural variation at the catalytic site of bacterial DHFR.     

Electrochemical Deodorization and Disinfection of Hog Manure

Electrolysis of liquid hog manure under direct current achieved amelioration of odour, in terms of both odour quality and odour intensity, and simultaneously reduced the population of odour‐causing bacteria by two orders of magnitude. A comparison of anode materials indicated that hydroxyl radical‐forming anodes (boron‐doped diamond and Ebonex) were the most effective, but unfortunately these materials are not yet available commercially in large size format. Dimensionally stable anodes composed of Ti/IrO₂ were found to be satisfactory; lead‐based anodes leached unacceptable quantities of inorganic lead into the treated manure, and graphite anodes tended to disintegrate on long‐term use. The mechanism of action of the bactericidal effect involves a combination of toxicity by O₂ that is released at the anode and hypochlorination due to the chloride ion that is present in manure. The proposed technology was shown to be successful at the 27 L scale in an on‐farm demonstration.