Skeletal muscle fatty acids shift from oxidation to storage upon dexamethasone treatment in chickens

The effect of an exogenous glucocorticoid on the lipid metabolism and fatty acid pattern of skeletal muscle in broiler chickens (Gallus gallus domesticus) was investigated in vivo and in vitro. Male Arbor Acres chickens were subjected to dexamethasone (DEX) treatment for 3days. We found that DEX retarded body growth, facilitated lipid accumulation in adipose and skeletal muscle tissues, and elevated the thigh monounsaturated fatty acids (MUFA) to saturated fatty acids (SFA) ratio at fasted state. DEX-treated chickens exhibited increased stearoyl-CoA desaturase-1 (SCD1) activity and decreased carnitine palmitoyltransferase-1 (CPT1) activity in the thigh muscle under fasting conditions and in primary cultured myoblasts. Phosphorylation of AMP-activated protein kinase alpha at Thr172 did not occur in vivo but was increased in vitro by DEX. In cells exposed to DEX, fatty acid transport protein-1 mRNA expression and fatty acid storage were enhanced while fatty acid oxidation was repressed. In conclusion, in oxidative muscle of fasted chickens, DEX stimulated uptake of myocellular fatty acids which was stored with the modified MUFA to SFA ratio in a process that maybe involved SCD1 activation. The altered fatty acid composition together with the inactivation of CPT1 showed an increased tendency towards fatty acid accumulation as opposed to oxidation. These findings provide important insight concerning the influence of glucocorticoids on lipid metabolism.

Deaths observed in Medicare beneficiaries: average attributable fraction and its longitudinal extension for many diseases

Calculating the longitudinal extension of the average attributable fraction (LE-AAF) for many risk factors (RFs) requires a two-stage computational process using only those combinations of RFs observed in the dataset. We first screen candidates RFs in a Cox Model, and assuming piecewise constant hazards, use pooled logistic regression to model the probability of death as a function of combinations of selected RFs. We average the iterative differencing of the attributable fractions calculated for all overlapping subsets of co-occurring RFs to obtain a LE-AAF for each RF that is additive and symmetrical. We illustrate by partitioning the additive proportions of death from 10 different groupings of acute and chronic diseases, on a national sample of older persons from the US (Medicare Beneficiary Survey) over a 4-year period and compare with results reported by the National Center for Healthcare Statistics. We conclude that careful screening of RFs with analysis restricted to extant combinations greatly reduces computational burden. LE-AAF accounted for a cumulative total of 66% of the deaths in our sample, compared with the 83% accounted for by the National Center for Healthcare Statistics.

Co-evolution of genomic islands and their bacterial hosts revealed through phylogenetic analyses of 17 groups of homologous genomic islands

Horizontal gene transfer is an important mechanism for the evolution of microbial genomes, and many horizontal gene transfer events are facilitated by genomic islands (GIs). Until now, few reports have provided evidence for the co-evolution of horizontally transferred genes and their hosts. We obtained 17 groups of homologous GIs, all of which appear in 8 or more bacterial strains of the same species or genus. Using phylogenetic analyses, we found that the topological structure of a distance tree based on the proteins of each group of homologous GIs was consistent with that based on the complete proteomes of the hosts. This result clearly indicates that GIs and their bacterial hosts have co-evolved. In addition to presenting and providing evidence for a novel concept, i.e., the co-evolution of GIs and their bacterial hosts, we also describe a new and interesting detail for the phylogenetic analysis of horizontally transferred genes: consistent phylogenetic trees can be obtained by focusing on homologous GIs despite the commonly accepted theory that the phylogenies of horizontally transferred sequences and host organisms should be inconsistent.

Cool perch availability improves the performance and welfare status of broiler chickens in hot weather

A study was conducted to determine whether water-cooled perches would be preferred by commercial broilers exposed to a hot ambient environment, and subsequently, whether utilization of these perches would improve performance and the well-being of birds, beyond those provided by normal perches. Four hundred and thirty-two 14-d-old male chickens from a commercial fast-growing strain (Arbor Acres) were housed in the following conditions: 1) cool perches, 2) normal perches, and 3) control pens with no perches. The results showed that there was greater use of cool perches than normal perches for broiler chickens during summer (F1, 4=125, P=0.0004). Cool perches increased BW gain (F2, 6=5.44, P=0.0449) and breast (F2, 24=3.31, P=0.0539) and thigh muscle yields (F2, 24=6.29, P=0.0063), while decreasing abdominal fat deposition (F2, 24=7.57, P=0.0028), cooking loss (pectoralis major, F2, 24=3.30, P=0.0542; biceps femoris, F2, 24=3.42, P=0.0493), percentage of panting birds (F2, 6=102, P<0.0001), and scores of footpad (F2, 6=122, P<0.0001) and hock (F2, 6=68.2, P<0.0001) burn, and abdominal plumage condition (F2, 6=52.0, P=0.0002), particularly toward the end of the rearing period. In contrast, normal perches hardly affected growth performance, carcass composition, meat quality and behavioral patterns, and appeared to worsen the welfare status, including footpad and hock burns and abdominal plumage condition, due to a lower occupancy rate. Cool perches offer a thermoregulatory and performance advantage to broilers exposed to a hot environment and appear to be a management strategy for improving the production and well-being of commercial broilers.

Altered gene and protein expression of glucose transporter1 underlies dexamethasone inhibition of insulin-stimulated glucose uptake in chicken muscles

A study was performed to characterize the effects of dexamethasone (DEX) and insulin administration on gene expression of glucose transporters (GLUT) in chicken (Gallus gallus domesticus) skeletal muscles and in cultured embryonic myoblasts. Three groups of 1-wk-old male chickens were randomly subjected to one of the following treatments for 7 d: DEX (a subcutaneous injection of 1 mg/kg BW, twice daily at 0800 h and 2000 h), controls (injected with saline), and pair-fed controls (restricted to the same feed intake as for the DEX treatment). Expressions of GLUT-1, GLUT-3, GLUT-8, and 18S rRNA mRNA were determined by quantitative reverse transcription PCR in the pectoralis major (PM) and biceps femoris (BF) muscles. Using chicken embryonic myoblasts (CEM), the interaction between DEX (200 nM) and insulin (100 nM) administration was evaluated on GLUT gene and GLUT-1 protein expressions and 2-deoxy-D-[1, 2-(3)H]-glucose (2-DG) uptake. Myoblasts were incubated with serum-free medium for 3 h in the presence or absence of insulin (0, 0.02, 0.1, 0.5, and 2.5 μM). Although GLUT-1 is not considered an insulin-responsive GLUT in mammals, this study shows that insulin stimulated 2-DG uptake and GLUT-1 mRNA and protein expression in CEM (P < 0.0001), suggesting that both are regulated in chicken skeletal muscle. Dexamethasone inhibited insulin-stimulated glucose uptake in CEM (P < 0.0001), likely accounting for insulin resistance in skeletal muscles. The results of the present study indicate that the altered GLUT-1 gene and protein expression may contribute to the insulin resistance induced by DEX treatment in chicken muscles.

Dexamethasone facilitates lipid accumulation in chicken skeletal muscle

The effects of glucocorticoid on lipid metabolism of broiler chicken (Gallus gallus domesticus) skeletal muscle were investigated. Male Arbor Acres chickens (35 days old) were subjected to dexamethasone treatment for 3 days. We found that dexamethasone retards body growth while facilitating lipid accumulation. In M. pectoralis major (PM), dexamethasone increased the expression of glucocorticoid receptor (GR), fatty acid transport protein 1 (FATP1), heart fatty acid-binding protein (H-FABP) and long-chain acyl-CoA dehydrogenase (LCAD) mRNA and decreased the expression of liver carnitine palmitoyltransferase 1 (L-CPT1), adenosine-monophosphate-activated protein kinase (AMPK) α2 and lipoprotein lipase (LPL) mRNA. LPL activity was also decreased. In M. biceps femoris (BF), the levels of GR, FATP1 and L-CPT1 mRNA were increased. AMPKα (Thr172) phosphorylation and CTP1 activity of skeletal muscle were decreased by dexamethasone. In fed chickens, dexamethasone enhanced very low-density lipoprotein receptor (VLDLR) expression and AMPK activity in muscle, but it impaired the expression of LPL and L-CPT1 mRNA and LPL activity in PM and augmented the expression of GR, LPL, H-FABP, L-CPT1, LCAD and AMPKα2 mRNA in BF. Adipose triglyceride lipase (ATGL) protein expression was not affected by dexamethasone. In conclusion, in the fasting state, dexamethasone-induced-retarded fatty acid utilisation may be involved in the augmented intramyocellular lipid accumulation in both glycolytic (PM) and oxidative (BF) muscle tissues. In the fed state, dexamethasone promoted the transcriptional activity of genes related to lipid uptake and oxidation in muscles. Unmatched lipid uptake and utilisation are suggested to be involved in the augmented intramyocellular lipid accumulation.

Expectation enhances event-related responses to affective stimuli

How the expectation of forthcoming emotional events influences individuals' behaviors and brain responses to such events remains controversial. The present study addressed this issue using event-related potentials (ERPs) to overcome limitations in research techniques. In addition, a no cue condition was adopted as the unexpected condition to make the research paradigm closer to real life situations for ecological validity. Behavioral results showed that positive stimuli were experienced more pleasantly and negative ones were experienced more unpleasantly during the expected condition than the unexpected one. ERPs results also displayed larger P2, N2 and LPP amplitudes in the expected condition, regardless of stimulus valence. The finding that expected emotional events evoke enhanced behavioral and brain responses than the unexpected ones do provides a strong piece of evidence for the effect of expectation on emotion processing.

Effects of semen processing on the generation of reactive oxygen species and mitochondrial membrane potential of human spermatozoa

This study was designed to evaluate the effects of semen processing on the generation of intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) in spermatozoa, and to develop reliable indexes for the evaluation of sperm quality during sperm preparation. Swim-up and density gradient centrifugation methods were used to separate semen in oligoasthenoteratozoospermia (OAT), leucocytospermia (LC) and normozoospermia groups. Levels of ROS and MMP were measured by flow cytometry. Before preparation, the patients with abnormal semen parameters had a lower MMP and higher ROS, and there was a negative correlation between MMP and ROS. The levels of MMP and ROS increased significantly, especially ROS produced by swim-up. A significant difference was found between the correlation of MMP and total normal motile sperm count after preparation in the OAT group. The level of ROS was associated with the amount of white blood cells in the LC group. The MMP can be used as an objective index to evaluate the sperm quality of OAT patients, and the combination of MMP and ROS can be used to assess the efficiency of sperm preparation in LC patients. These findings can guide selection of the ideal sperm separation technique for different sperm samples.

Genome-wide identification and characterization of simple sequence repeat loci in grape phylloxera, Daktulosphaira vitifoliae

A genome-wide sequence search was conducted to identify simple sequence repeat (SSR) loci in phylloxera, Daktulosphaira vitifoliae, a major grape pest throughout the world. Collectively, 1524 SSR loci containing mono-, di-, tri-, tetra-, penta-, and hexanucleotide motifs were identified. Among them, trinucleotide repeats were the most abundant in the phylloxera genome (34.4%), followed by hexanucleotide (20.4%) and dinucleotide (19.6%) repeats. Mono-, tetra- and pentanucleotide repeats were found at a frequency of 1.3, 11.2 and 12.9%, respectively. The abundance and inherent variations in SSRs provide valuable information for developing molecular markers. The high levels of allelic variation and codominant features of SSRs make this marker system a useful tool for genotyping, diversity assessment and population genetic studies of reproductive characteristics of phylloxera in agricultural and natural populations.

Skin carotenoid status measured by resonance Raman spectroscopy as a biomarker of fruit and vegetable intake in preschool children

BACKGROUND/OBJECTIVE

Dietary assessment in children is difficult, suggesting a need to develop more objective biomarkers of intake. Resonance Raman spectroscopy (RRS) is a non-invasive, validated method of measuring carotenoid status in skin as a biomarker of fruit/vegetable intake. The purpose of this study was to examine the feasibility of using RRS in preschool children, to describe inter-individual variability in skin carotenoid status and to identify factors associated with the biomarker in this population.

SUBJECTS/METHODS

We conducted a cross-sectional study of 381 economically disadvantaged preschoolers in urban centers in Connecticut (USA). In all, 85.5% were black non-Hispanic or Hispanic/Latino, and 14.1% were obese and 16.9% were overweight by age- and sex-specific body mass index (BMI) percentiles. Children had their skin carotenoid status assessed by RRS in the palm of the hand. Fruit/vegetable consumption was assessed by a brief parent/guardian-completed food frequency screener and a liking survey.

RESULTS

We observed inter-individual variation in RRS values that was nearly normally distributed. In multiple regression analysis, higher carotenoid status, measured by RRS, was positively associated with fruit/vegetable consumption (P=0.02) and fruit/vegetable preference (P<0.01). Lower carotenoid status was observed among younger children, those participating in the US Supplemental Nutrition Assistance Program, and those with greater adiposity (P<0.05 for all).

CONCLUSIONS

We observed wide variability in skin carotenoid status in a population of young children, as assessed by RRS. Parent-reported fruit/vegetable intake and several demographic factors were significantly associated with RRS-measured skin carotenoid status. We recommend further development of this biomarker in children, including evaluating response to controlled interventions.

Subclinical endothelial dysfunction and low-grade inflammation play roles in the development of erectile dysfunction in young men with low risk of coronary heart disease

The purpose of this study is to investigate the possible underlying pathogenesis of erectile dysfunction(ED) in young men with low risk of coronary heart disease and no well-known aetiology. To conduct this study, 122 patients with ED under the age of 40 were enrolled, along with 33 age-matched normal control subjects. The patients with ED had significantly higher levels of systolic blood pressure (SBP), total cholesterol and triglyceride, high sensitivity C-reactive protein (hs-CRP), greater carotid intima-media thickness (CIMT) and Framingham risk score (FRS) than the control group, though all of these values were within the respective normal range. Further, the brachial artery flow- mediated vasodilation (FMD) values were significantly lower in ED patients and correlated positively with the severity of ED (r = 0.714, p < 0.001). When these significant factors were studied in the multivariate logistic regression model, FMD, SBP, hs-CRP and FRS remained the statistical significance. The receiver-operating characteristic (ROC) analysis demonstrated that FMD had a high ability to predict ED in young male with low FRS [area under the curve (AUC) 0.921, p < 0.001]. The cutoff value of FMD <10.25% had sensitivity of 82.8% and specificity of 100% for diagnosis of ED. FRS and hs- CRP were also proven to be predictors of ED (AUC 0.812, p < 0.001; AUC 0.645, p = 0.011, respectively). The results of this study validated that subclinical endothelial dysfunction and low-grade inflammation may be the underlying pathogenesis of ED with no well-known aetiology. Young patients complaining of ED should be screened for cardiovascular risk factors and possible subclinical atherosclerosis. Measurement of FMD, hs-CRP and FRS can improve our ability to predict and treat ED, as well as subclinical cardiovascular disease early for young male.