Soy versus whey protein bars: Effects on exercise training impact on lean body mass and antioxidant status

BACKGROUND: Although soy protein may have many health benefits derived from its associated antioxidants, many male exercisers avoid soy protein. This is due partly to a popular, but untested notion that in males, soy is inferior to whey in promoting muscle weight gain. This study provided a direct comparison between a soy product and a whey product. METHODS: Lean body mass gain was examined in males from a university weight training class given daily servings of micronutrient-fortified protein bars containing soy or whey protein (33 g protein/day, 9 weeks, n = 9 for each protein treatment group). Training used workouts with fairly low repetition numbers per set. A control group from the class (N = 9) did the training, but did not consume either type protein bar. RESULTS: Both the soy and whey treatment groups showed a gain in lean body mass, but the training-only group did not. The whey and training only groups, but not the soy group, showed a potentially deleterious post-training effect on two antioxidant-related related parameters. CONCLUSIONS: Soy and whey protein bar products both promoted exercise training-induced lean body mass gain, but the soy had the added benefit of preserving two aspects of antioxidant function

Identification of important regressor groups, subgroups and individuals via regularization methods: Application to gut microbiome data

Motivation: Gut microbiota can be classified at multiple taxonomy levels. Strategies to use changes in microbiota composition to effect health improvements require knowing at which taxonomy level interventions should be aimed. Identifying these important levels is difficult, however, because most statistical methods only consider when the microbiota are classified at one taxonomy level, not multiple.Results: Using L1 and L2 regularizations, we developed a new variable selection method that identifies important features at multiple taxonomy levels. The regularization parameters are chosen by a new, data-adaptive, repeated cross-validation approach, which performed well. In simulation studies, our method outperformed competing methods: it more often selected significant variables, and had small false discovery rates and acceptable false-positive rates. Applying our method to gut microbiota data, we found which taxonomic levels were most altered by specific interventions or physiological status.Availability: The new approach is implemented in an R package, which is freely available from the corresponding author. © 2013 The Author 2013. Published by Oxford University Press. All rights reserved

Prior experience with photostimulation enhances photo-induced reproductive response in female house finches

In vertebrates, reproductive output often increases with age. Unlike older birds, first-year photoperiodic birds lack experience with the reproductively stimulatory effects of long day lengths (photostimulation). We examined whether age-related differences in annual reproductive development could be partially attributed to previous experience with photostimulation in the photoperiodic house finch (Carpodacus mexicanus). By manipulating photoperiod, we generated 2 groups of first-year females: a photo-experienced group that underwent 1 photoperiodically induced cycle of gonadal development and regression and a photo-naïve group exposed to long days since hatch. We transferred both groups from long to short days and then photostimulated and exposed them to male birdsong prior to sacrifice. Following concurrent photostimulation, both groups exhibited similar plasma luteinizing hormone surges and hypothalamic vasoactive intestinal polypeptide immunoreactivity. In contrast, hypothalamic gonadotropin-releasing hormone immunoreactivity and circulating vitellogenin levels were higher in photo-experienced birds, and yolk deposition occurred in only 2 females, both of which were photo-experienced. Our results demonstrate that photo-experience enhances some aspects of early photo-induced reproductive development and raise the hypothesis that photo-experience may account for at least some age-related variation in reproductive output

Structured variable selection with q-values

When some of the regressors can act on both the response and other explanatory variables, the already challenging problem of selecting variables when the number of covariates exceeds the sample size becomes more difficult. A motivating example is a metabolic study in mice that has diet groups and gut microbial percentages that may affect changes in multiple phenotypes related to body weight regulation. The data have more variables than observations and diet is known to act directly on the phenotypes as well as on some or potentially all of the microbial percentages. Interest lies in determining which gut microflora influence the phenotypes while accounting for the direct relationship between diet and the other variables. A new methodology for variable selection in this context is presented that links the concept of q-values from multiple hypothesis testing to the recently developed weighted Lasso. © The Author 2013. Published by Oxford University Press. All rights reserved

Prevalence of and risk factors associated with atherosclerosis in psittacine birds

OBJECTIVE: To estimate the prevalence of clinically relevant atherosclerotic lesions in birds and identify epidemiological variables and illness types associated with development of atherosclerosis. DESIGN: Retrospective case-control study. SAMPLE: Records of 7683 psittacine birds, including 525 with advanced atherosclerosis. PROCEDURES: 5 pathology centers provided databases and access to histopathology slides. Age and sex were collected for all birds of the Amazona, Ara, Cacatua, Nymphicus, and Psittacus genera. Databases were searched for atherosclerosis cases, and slides were reviewed for the presence of type IV through VI atherosclerotic lesions. Results were used to build several multiple logistic models to define the association between advanced atherosclerosis and age, sex, genus, illness type, and specific lesions. Prevalence was reported as a function of age, sex, and genus. RESULTS: In the first model including 7683 birds, age, female sex, and the genera Psittacus, Amazona, and Nymphicus were significantly associated with clinically relevant atherosclerosis detected via necropsy. Subsequent models of 1,050 cases revealed further associations with reproductive disease, hepatic disease, and myocardial fibrosis, controlling for age, sex, and genus. CONCLUSIONS AND CLINICAL RELEVANCE: Age, female sex, and 3 genera appeared to be positively associated with the presence of advanced atherosclerotic lesions in psittacine birds. This information may be useful in clinical assessment of the cardiovascular system and patient management. Reproductive diseases were the only potentially modifiable risk factor identified and could be a target for prevention in captive psittacine birds