Effect of exercise duration on postprandial hypertriglyceridemia in men with metabolic syndrome.

We examined the effect of exercise on postprandial hypertriglyceridemia (PHTG) and insulin resistance in individuals with metabolic syndrome. Subjects were 10 hypertriglyceridemic men with insulin resistance [age = 35.0 +/- 1.8 yr, body weight = 90.7 +/- 3.3 kg, fasting triglyceride (TG) = 2.6 +/- 0.4 mmol/l, peak oxygen consumption ((.)Vo(2peak)) = 36.0 +/- 1.3 ml(-1).kg(-1).min(-1), and homeostatic model assessment of insulin resistance (HOMA-IR)= 3.1 +/- 0.3]. Each participant performed a control trial (Ctr; no exercise) and three exercise trials at 60% of their (.)Vo(2peak) for 30 min (30 min-Ex), 45 min (45 min-Ex) and 60 min (60 min-Ex). All subjects had a fat meal in each trial. In the exercise trials, the subject jogged on a treadmill for a designated duration of 12 h before ingestion of a fat meal. Blood samples were taken at 0 h (before the meal) and at 2, 4, 6, and 8 h after the meal. The plasma TG, area score under TG concentration curve over an 8-h period (TG AUC) after the meal, and HOMA-IR were analyzed. The TG AUC scores in both the 45 min-Ex and 60 min-Ex were 31 and 33% lower, respectively, than Ctr (P < 0.02). There were no significant differences in TG AUC scores between the 30 min-Ex and the Ctr (P > 0.05). There were no trial differences in the fasting plasma glucose concentration (P > 0.05). HOMA-IR values in the 30 min-Ex, 45 min-Ex, and 60 min-Ex trials were lower than the Ctr (P < 0.03), but no significant differences were found in HOMA-IR among the exercise trials. The results suggest that for physically inactive individuals with metabolic syndrome, exercising at moderate intensity for 45 min effectively attenuates PHTG while exercise for 30 min is sufficient to improve insulin action.     

Associations of physical activity with gut microbiota in pre-adolescent children

[Purpose] To determine whether physical activity (PA), primarily the recommended 60 minutes of moderate-to-vigorous PA, is associated with gut bacterial microbiota in 10-year-old children.[Methods] The Block Physical Activity Screener, which provides minutes/day PA variables, was used to determine whether the child met the PA recommendations. 16S rRNA sequencing was performed on stool samples from the children to profile the composition of their gut bacterial microbiota. Differences in alpha diversity metrics (richness, Pielou’s evenness, and Faith’s phylogenetic diversity) by PA were determined using linear regression, whereas beta diversity (unweighted and weighted UniFrac) relationships were assessed using PERMANOVA. Taxon relative abundance differentials were determined using DESeq2.[Results] The analytic sample included 321 children with both PA and 16S rRNA sequencing data (mean age [SD] =10.2 [0.8] years; 54.2% male; 62.9% African American), where 189 (58.9%) met the PA recommendations. After adjusting for covariates, meeting the PA recommendations as well as minutes/day PA variables were not significantly associated with gut richness, evenness, or diversity (p ≥ 0.19). However, meeting the PA recommendations (weighted UniFrac R² = 0.014, p = 0.001) was significantly associated with distinct gut bacterial composition. These compositional differences were partly characterized by increased abundance of Megamonas and Anaerovorax as well as specific Christensenellaceae_R-7_group taxa in children with higher PA.[Conclusion] Children who met the recommendations of PA had altered gut microbiota compositions. Whether this translates to a reduced risk of obesity or associated metabolic diseases is still unclear.     

Serum PAF acetylhydrolase increases during neonatal maturation

Acetylhydrolase is an acid-labile, 43 kd protein that catalyzes the degradation of platelet activating factor (PAF), a potent phospholipid inflammatory mediator, to its biologically inactive metabolite lysoPAF. PAF has a short half-life, thus acetylhydrolase plays an important role in its regulation. Since previous work suggests that PAF may be involved in certain neonatal diseases such as necrotizing enterocolitis, we studied the effect of age on acetylhydrolase activity. Serum acetylhydrolase activity was quantified using radio-labelled PAF and measuring reaction products. Serum samples were obtained prospectively from 70 subjects ranging in age from 4 hr to 48 yr. Acetylhydrolase activity was lower for newborns (less than 3 wk) than all other age ranges (8.2 +/- 1.4 nmole/ml/min vs 30.0 +/- 1.6 nmole/ml/min, p less than .01). Furthermore, enzyme activity increased linearly with respect to the natural logarithm of age from 0 days to 6 weeks (r = 0.65, p less than .001). By 6 weeks of life acetylhydrolase activity approached values of older children and adults. Newborn acetylhydrolase activity was similar between term and preterm infants (8.6 +/- 1.9 nmole/ml/min vs 7.2 +/- 2.4 nmole/ml/min, p = NS). We conclude that acetylhydrolase activity is low in human neonates and increases during the first 6 weeks of life. These results suggest that newborn infants may be at increased risk for pathophysiologic processes mediated by PAF.     

Transgressive character expression in a hybrid sunflower species

Diploid hybrid lineages often are ecologically distinct from their parental species. However, it is unclear whether this niche divergence is typically achieved via hybrid intermediacy, a mixture of parental traits, and/or the evolution of extreme (transgressive) morphological and ecophysiological features. Here we compare an extensively studied hybrid sunflower species, Helianthus anomalus, with its putative parents, H. annuus and H. petiolaris, for 41 morphological and 12 ecophysiological traits. Helianthus anomalus was morphologically intermediate for one trait (2.4%), parental-like for 23 traits (56.1%), and transgressive for 17 traits (41.5%). For ecophysiological traits, H. anomalus was not significantly different from one or both parents for nine traits (75%), and was transgressive for the remaining three (25%). Thus, H. anomalus appears to be a mosaic of parental-like and transgressive phenotypes. Although the fitness effects of the transgressive characters are not yet known, many of these characters are consistent with adaptations reported for other sand dune plants. Genetic studies are currently underway to ascertain whether these extreme characters arose as a direct byproduct of hybridization or whether they evolved via mutational divergence.     

Kinetic characterization of wild-type and proton transfer-impaired variants of beta-carbonic anhydrase from Arabidopsis thaliana

We have cloned and overexpressed a truncated, recombinant form of beta-carbonic anhydrase from Arabidopsis thaliana. The wild-type enzyme and two site-directed variants, H216N and Y212F, have been kinetically characterized both at steady state by stopped-flow spectrophotometry and at chemical equilibrium by (18)O isotope exchange methods. The wild-type enzyme has a maximal k(cat) for CO2 hydration of 320 ms(-1) and is rate limited by proton transfer involving two residues with apparent pK(a) values of 6.0 and 8.7. The mutant enzyme H216N has a maximal k(cat) at high pH that is 43% that of wild type, but is only 5% that of wild type at pH 7.0. (18)O exchange studies reveal that the effect of the mutations H216N or Y212F is primarily on proton transfer steps in the catalytic mechanism and not in the rate of CO2-HCO3- exchange. These results suggest that residues His-216 and Tyr-212 are both important for efficient proton transfer in A. thaliana carbonic anhydrase.     

Acidomucin goblet cell expansion induced by parenteral nutrition in the small intestine of piglets

Total parenteral nutrition (TPN) impairs small intestine development and is associated with barrier failure, inflammation, and acidomucin goblet cell expansion in neonatal piglets. We examined the relationship between intestinal goblet cell expansion and molecular and cellular indices of inflammation in neonatal piglets receiving TPN, 80% parenteral + 20% enteral nutrition (PEN), or 100% enteral nutrition (control) for 3 or 7 days. Epithelial permeability, T cell numbers, TNF-alpha and IFN-gamma mRNA expression, and epithelial proliferation and apoptosis were compared with goblet cell numbers over time. Epithelial permeability was similar to control in the TPN and PEN jejunum at day 3 but increased in the TPN jejunum by day 7. By day 3, intestinal T cell numbers were increased in TPN but not in PEN piglets. However, goblet cell expansion was established by day 3 in both the TPN and PEN ileum. Neither TNF-alpha nor IFN-gamma mRNA expression in the TPN and PEN ileum correlated with goblet cell expansion. Thus goblet cell expansion occurred independently of overt inflammation but in association with parenteral feeding. These data support the hypothesis that goblet cell expansion represents an initial defense triggered by reduced epithelial renewal to prevent intestinal barrier failure.     

The association between lameness,ovarian cysts and fertility in lactating dairy cows

The objective of this observational study was to evaluate the association between lameness, ovarian cysts, and fertility in lactating dairy cows. Data analysis of historical records from a 3000 Holstein farm was conducted. Sixty-five cows that became lame within 30 days postpartum were used as cases, and 130 nonlame cows served as controls. The outcome variables were incidence of ovarian cysts (OC, %), conception rate at first service (CRFS, %), overall pregnancy rate (PR, %), and calving to first service interval (CFSI, day), Incidence of OC and CRFS were analyzed by logistic regression, PR by survival analysis and CFSI by ANOVA. Lame cows had a lower CRFS (17.5% versus 42.6%) and higher incidence of OC (25.0% versus 11.1%) than controls (P0.05). There was a multicollinearity relationship between lameness and ovarian cysts. The results show that cows that became lame within the first 30 days postpartum were associated with a higher incidence of ovarian cysts, a lower likelihood of pregnancy, and lower fertility than control cows. Because this is an observational study it is not possible to conclude a cause-effect relationship.     

Harmonic analysis of perfusion pumps

The controversy over the use of nonpulsatile versus pulsatile pumps for maintenance of normal organ function during ex vivo perfusion has continued for many years, but resolution has been limited by lack of a congruent mathematical definition of pulsatility. We hypothesized that the waveform frequency and amplitude, as well as the underlying mean distending pressure are all key parameters controlling vascular function. Using discrete Fourier Analysis, our data demonstrate the complexity of the pulmonary arterial pressure waveform in vivo and the failure of commonly available perfusion pumps to mimic in vivo dynamics. In addition, our data show that the key harmonic signatures are intrinsic to the perfusion pumps, are similar for flow and pressure waveforms, and are unchanged by characteristics of the downstream perfusion circuit or perfusate viscosity.