Gluteal Muscle Activation During Common Yoga Poses

BackgroundApproximately 24% of physical therapists report regularly using yoga to strengthen major muscle groups. Although clinicians and athletes often use yoga as a form of strength training, little is known about the activation of specific muscle groups during yoga poses, including the gluteus maximus and medius.Hypothesis/PurposeThe purpose of this study was to measure gluteus maximimus and gluteus medius activation via electromyography (EMG) during five common yoga poses. A secondary purpose of the current study was to examine differences in muscle activation between sexes and experience levels.Study DesignCross-SectionalMethodsThirty-one healthy males and females aged 18-35 years were tested during five yoga poses performed in a randomized order. Surface EMG electrodes were placed on subjects’ right gluteus maximus and gluteus medius. Subjects performed the poses on both sides following a maximal voluntary isometric contraction (MVIC) test for each muscle. All yoga pose EMG data were normalized to the corresponding muscle MVIC data.ResultsHighest gluteus maximus activation occurred during Half Moon Pose on the lifted/back leg (63.3% MVIC), followed by the stance/front leg during Half Moon Pose (61.7%), then the lifted/back leg during Warrior Three Pose (46.1%). Highest gluteus medius activation occurred during Half Moon Pose on the lifted/back leg (41.9%), followed by the lifted/back leg during the Warrior Three Pose (41.6%). A significant difference was found in %MVIC of gluteus medius activity between male and female subjects (p = 0.026), and between experienced and inexperienced subjects (p = 0.050), indicating higher activation among males and inexperienced subjects, respectively.ConclusionHalf Moon Pose and Warrior Three Pose elicited the highest activation for both the gluteus maximus and the gluteus medius. Higher gluteus medius activation was seen in males and inexperienced subjects compared to their female and experienced counterparts.Level of Evidence3     

Emergency department blood transfusion: the first two units are free

Introduction

Studies on blood product transfusions after trauma recommend targeting specific ratios to reduce mortality. Although crystalloid volumes as little as 1.5 L predict increased mortality after trauma, little data is available regarding the threshold of red blood cell (RBC) transfusion volume that predicts increased mortality.

Materials and methods

Data from a level I trauma center between January 2000 and December 2008 were reviewed. Trauma patients who received at least 100 mL RBC in the emergency department (ED) were included. Each unit of RBC was defined as 300 mL. Demographics, RBC transfusion volume, and mortality were analyzed in the nonelderly (<70 y) and elderly (≥70 y). Multivariate logistic regression was performed at various volume cutoffs to determine whether there was a threshold transfusion volume that independently predicted mortality.

Results

A total of 560 patients received ≥100 mL RBC in the ED. Overall mortality was 24.3%, with 22.5% (104 deaths) in the nonelderly and 32.7% (32 deaths) in the elderly. Multivariate logistic regression demonstrated that RBC transfusion of ≥900 mL was associated with increased mortality in both the nonelderly (adjusted odds ratio 2.06, P = 0.008) and elderly (adjusted odds ratio 5.08, P = 0.006).

Conclusions

Although transfusion of greater than 2 units in the ED was an independent predictor of mortality, transfusion of 2 units or less was not. Interestingly, unlike crystalloid volume, stepwise increases in blood volume were not associated with stepwise increases in mortality. The underlying etiology for mortality discrepancies, such as transfusion ratios, hypothermia, or immunosuppression, needs to be better delineated.     

Noggin resistance contributes to the potent osteogenic capability of BMP9 in mesenchymal stem cells

Mesenchymal stem cells (MSCs) are multipotent progenitors and can differentiate into osteogenic, chondrogenic, and adipogenic lineages. Bone morphogenetic proteins (BMPs) play important roles in stem cell proliferation and differentiation. We recently demonstrated that BMP9 is a potent but less understood osteogenic factor. We previously found that BMP9‐induced ectopic bone formation is not inhibited by BMP3. Here, we investigate the effect of BMP antagonist noggin on BMP9‐induced osteogenic differentiation. BMP antagonists noggin, chording, gremlin, follistatin, and BMP3 are highly expressed in MSCs, while noggin and follistatin are lowly expressed in more differentiated pre‐osteoblast C2C12 cells. BMP9‐induced osteogenic markers and matrix mineralization are not inhibited by noggin, while noggin blunts BMP2, BMP4, BMP6, and BMP7‐induced osteogenic markers and mineralization. Likewise, ectopic bone formation by MSCs transduced with BMP9, but not the other four BMPs, is resistant to noggin inhibition. BMP9‐induced nuclear translocation of Smad1/5/8 is not affected by noggin, while noggin blocks BMP2‐induced activation of Smad1/5/8 in MSCs. Noggin fails to inhibit BMP9‐induced expression of downstream targets in MSCs. Thus, our results strongly suggest that BMP9 may effectively overcome noggin inhibition, which should at least in part contribute to BMP9's potent osteogenic capability in MSCs. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1796–1803, 2013     

Gill bacteria enable a novel digestive strategy in a wood-feeding mollusk

Bacteria play many important roles in animal digestive systems, including the provision of enzymes critical to digestion. Typically, complex communities of bacteria reside in the gut lumen in direct contact with the ingested materials they help to digest. Here, we demonstrate a previously undescribed digestive strategy in the wood-eating marine bivalve Bankia setacea, wherein digestive bacteria are housed in a location remote from the gut. These bivalves, commonly known as shipworms, lack a resident microbiota in the gut compartment where wood is digested but harbor endosymbiotic bacteria within specialized cells in their gills. We show that this comparatively simple bacterial community produces wood-degrading enzymes that are selectively translocated from gill to gut. These enzymes, which include just a small subset of the predicted wood-degrading enzymes encoded in the endosymbiont genomes, accumulate in the gut to the near exclusion of other endosymbiont-made proteins. This strategy of remote enzyme production provides the shipworm with a mechanism to capture liberated sugars from wood without competition from an endogenous gut microbiota. Because only those proteins required for wood digestion are translocated to the gut, this newly described system reveals which of many possible enzymes and enzyme combinations are minimally required for wood degradation. Thus, although it has historically had negative impacts on human welfare, the shipworm digestive process now has the potential to have a positive impact on industries that convert wood and other plant biomass to renewable fuels, fine chemicals, food, feeds, textiles, and paper products.Shipworms are important pest organisms that burrow in wood (Fig. 1), causing extensive damage to wooden structures in marine and brackish waters, including ships, boats, piers, and fishing equipment. However, these worm-like marine mollusks also provide benefits by clearing wood debris from navigable waters and transforming this recalcitrant material into their own more readily digestible biomass (1, 2). At least one shipworm species (Lyrodus pedicellatus) has been shown to grow and reproduce normally using wood as its sole particulate food source (3). However, unlike their terrestrial herbivorous and xylophagous counterparts, whose digestive systems contain complex communities of microbes (4–9), Bankia setacea and several other shipworm species accumulate and digest wood in the cecum (Fig. 1 A and B), a region of the foregut that is devoid of any conspicuous microbial community (10).Open in a separate windowFig. 1.Anatomy of B. setacea. (A) Schematic diagram of B. setacea. (B) B. setacea removed from its burrow. (Scale bar: 1 cm.) (C) B. setacea exposed in wood burrow. The abrasive surfaces of the valves (shells) excavate wood particles that are ingested and transported to the cecum for digestion. a, anus; b, burrow; c, cecum; fg, food groove; gi, gill; gn, gonad; I, intestine; m, mouth; p, pallets; si, siphons; st, stomach; v, valve. (Scale bar: 1 cm.) B and C courtesy of Jeffrey Schilling, Oregon Health & Science University, Portland, OR. In B, the cecum (orange) is partially obscured by the gonad (white). (D) Transmission electron micrograph showing endosymbionts within a single bacteriocyte in the B. setacea gill. e, endosymbonts; n, nucleus. (Scale bar: 2 μm.) (Inset) Endosymbiont cells. (Scale bar: 250 nm.)Although the cecum of B. setacea is depauperate of microorganisms, dense communities of endosymbiotic bacteria (Fig. 1D) are found in an internal region of the gill referred to as the gland of Deshayes (11–15). Culture-independent 16S rRNA gene analyses have shown that the gill endosymbiont community of L. pedicellatus is composed of several endosymbiont types that are closely related to the polysaccharide-degrading gammaproteobacterium Saccharophagus degradans (11, 12, 16, 17) (Fig. 2A and Fig. S1A). These endosymbiont types include Teredinibacter turnerae, a cellulolytic and nitrogen-fixing gammaproteobacterium that has been isolated in pure culture from the gills of many shipworm species from around the world (16, 18, 19). The metabolic capabilities displayed by T. turnerae when grown in vitro suggest two potential functions for the shipworm gill endosymbionts: (i) fixing nitrogen to supplement the host’s nitrogen-deficient diet of wood and (ii) producing hydrolytic enzymes that contribute to wood digestion (1, 18). Although the former function has been demonstrated experimentally (20), the latter has not until now.Open in a separate windowFig. 2.Gill endosymbiont community of B. setacea. (A) Bayesian phylogeny (16S rRNA) of cultivated and uncultivated gill endosymbionts of B. setacea (subtree from Fig. S1A). The area of closed circles is proportional to the fraction of the clone library represented by each OTU (Table S2). Posterior probabilities >0.5 are shown. (Scale bar: 0.05 substitutions per nucleotide position.) (B) FISH showing five gill tissue sections from B. setacea (columns), each dual-labeled with a bacteria-selective probe (EUB338; red) plus the indicated isolate-selective probe (green). (Scale bars: 100 μm.) Colocalization (yellow) of bacteria- and isolate-selective probes demonstrates that the four isolates account for most but not all (arrow) detectable gill endosymbionts. (Insets) Details of the boxed areas at a magnification and exposure appropriate to demonstrate the fainter but clearly detectable fluorescence in BsC2 containing bacteriocytes. (Scale bar: 5 μm.) Negative controls are shown in Fig. S1B.     

Circadian Polymorphisms in Night Owls,in Bipolars,and in Non-24-Hour Sleep Cycles

People called night owls habitually have late bedtimes and late times of arising, sometimes suffering a heritable circadian disturbance called delayed sleep phase syndrome (DSPS). Those with DSPS, those with more severe progressively-late non-24-hour sleep-wake cycles, and those with bipolar disorder may share genetic tendencies for slowed or delayed circadian cycles. We searched for polymorphisms associated with DSPS in a case-control study of DSPS research participants and a separate study of Sleep Center patients undergoing polysomnography. In 45 participants, we resequenced portions of 15 circadian genes to identify unknown polymorphisms that might be associated with DSPS, non-24-hour rhythms, or bipolar comorbidities. We then genotyped single nucleotide polymorphisms (SNPs) in both larger samples, using Illumina Golden Gate assays. Associations of SNPs with the DSPS phenotype and with the morningness-eveningness parametric phenotype were computed for both samples, then combined for meta-analyses. Delayed sleep and "eveningness" were inversely associated with loci in circadian genes NFIL3 (rs2482705) and RORC (rs3828057). A group of haplotypes overlapping BHLHE40 was associated with non-24-hour sleep-wake cycles, and less robustly, with delayed sleep and bipolar disorder (e.g., rs34883305, rs34870629, rs74439275, and rs3750275 were associated with n=37, p=4.58E-09, Bonferroni p=2.95E-06). Bright light and melatonin can palliate circadian disorders, and genetics may clarify the underlying circadian photoperiodic mechanisms. After further replication and identification of the causal polymorphisms, these findings may point to future treatments for DSPS, non-24-hour rhythms, and possibly bipolar disorder or depression.     

Generalization of Variants Identified by Genome‐Wide Association Studies for Electrocardiographic Traits in African Americans

Electrocardiographic (ECG) measurements vary by ancestry. Genome‐wide association studies (GWAS) have identified loci that contribute to ECG measurements; however, most are performed in Europeans collected from population‐based cohorts or surveys. The strongest associations reported are in NOS1AP with QT interval and SCN10A with PR and QRS durations. The extent to which these associations can be generalized to African Americans has yet to be determined. Using electronic medical records, PR and QT intervals, QRS duration, and heart rate were determined in 455 African Americans as part of the Vanderbilt Genome‐Electronic Records Project and Northwestern University NUgene Project. We tested for an association between these ECG traits and >930K SNPs. We identified a total 36 novel associations with PR interval, QRS duration, QT interval, and heart rate at p < 1.0 × 10^?6. Using published GWAS data, we compared our results with those previously identified in other populations. Five associations originally identified in other populations generalized with respect to statistical significance and direction of effect. A total of 43 associations have a consistent direction of effect with European and/or Asian populations. This work provides a catalogue of generalized versus nongeneralized associations, a necessary step in prioritizing GWAS‐identified regions for further fine‐mapping in diverse populations.     

Behavioral parenting interventions for child disruptive behaviors and anxiety: What's different and what's the same

This paper reviews the role of parents in behavioral interventions with children's disruptive and anxiety problems. The evolution of interventions for these two types of problems differs, as has the role of parents in these interventions. In contrast to the central role of parents in the conceptualization and treatment of disruptive behaviors, parents have played a more varied and less prominent role in the conceptualization and treatment of children's anxiety. Furthermore, the literature involving parents in the treatment of children's anxiety indicates these interventions are more efficacious than control groups but not more efficacious than intervening with the child alone. Some limited evidence emerges for parenting as a mediator in the treatment of disruptive behaviors, but not of anxiety, where the role of parenting has rarely been measured. Implications for conceptualizing the role of parents in intervention programs for youth are discussed and directions for future research are delineated (e.g., collecting long term follow-up data, examine moderators of treatment response, develop programs for comorbid diagnoses).