Exercising Metabolic, Ventilatory, and Cardiovascular Responses to Isometric Whole Body Vibration Exercise

Purpose: To determine if metabolic, ventilatory, or cardiovascular response to isometric squats with or without external load was enhanced by the addition of a whole body vibration (WBV). Methods: Fifteen subjects (28.4±6.5y; 173.7±8.6 cm; 75.5±20.8 kg) underwent four exercise sessions with three days’ rest between sessions. The sample included 7 males and 8 females. Subject performed 10-sets of one-minute isometrics squats with 45 degrees of knee flexion standing on a WBV platform under four conditions: Unloaded, Unloaded Vibration, Loaded, and Loaded Vibration. Each condition was performed on a separate day; the session order was presented at random. One-minute recovery was given between sets. During the vibration conditions, the plate vibrated at 4mm peak-to-peak displacement and 30Hz. Loaded sessions were performed with a barbell equal to 30% body weight across the subjects shoulder. Oxygen consumption (VO2) and ventilation (VE) were measured using a metabolic cart and heart rate was obtained using polar chest straps. A 2x2 ANOVA was used to evaluate main effects for vibration (vibration vs. no vibration), load (loaded vs. unloaded), and interactions. Results: There were significant vibration (p = 0.02) and load (p = 0.003) main effects for VO2. VO2 during vibration (9.2±3.3 mL.kg-1.min-1) was significantly greater than no vibration (7.9±1.2 mL.kg-1.min-1); VO2 was also greater during the loaded (9.6 ± 3.1 mL . kg-1 . min-1) condition compared to unloaded (7.5±1.1 mL.kg-1.min-1). There were significant vibration (p=0.01) and load (p=0.01) main effects for VE. VE during vibration (20.8±10.0 L.min-1) was greater than no vibration (17.8±4.8 L.min-1); VE was greater during loaded (21.5±9.4 L.min-1) conditions compared to unloaded (17.7±5.5 L.min-1). There were significant vibration (p=0.02) and load (p=0.008) main effects for HR. HR during vibration (97.0±20.3 beats . min-1) was greater than no vibration (86.8 ± 25.7 beats . min-1); HR was also greater during loaded (101.3±20.8 beats . min-1) conditions compared to unloaded (90.8±12.6 beats.min-1). No interaction effects were detected for VO2 (p= 0.16), VE (p=0.14), or HR (p=0.84). Conclusion: Significant differences were observed in VO2, VE, and HR while exercising with WBV. Differences were similar across loaded and unloaded conditions. It is unclear if these small differences would be sufficient to induce enhanced long-term training adaptations. Future research should investigate similar physiological responses during dynamic exercise with a range of loads. Further, research is also needed to determine if these responses are enhanced or diminished by the amplitude, frequency, or duration of the vibration stimulus

Nonapeptide influences on social behaviour: effects of vasotocin and isotocin on shoaling and interaction in zebrafish

Nonapeptides are important regulators of social behaviour across vertebrate taxa. While their role in simple grouping behaviour has been explored in estrildid finches, other taxa are understudied, prompting us to investigate nonapeptide influences on shoaling behaviour in zebrafish. Subjects received injections of isotocin, an isotocin antagonist, vasotocin, a vasotocin antagonist, or saline, followed by a test of grouping behaviour. Vasotocin decreased social interaction with the shoal. Unexpectedly, the vasotocin antagonist also reduced social interaction with the shoal, as well as general shoaling behaviour. Isotocin and its antagonist had minimal effects on grouping behaviours. These results suggest social interaction and shoaling are discrete aspects of sociality differentially influenced by vasotocin, although we cannot discount possible anxiogenic effects of vasotocin. Contrasting these results with studies in other systems demonstrates that each nonapeptide’s role in social behaviour varies across taxa, and cautions against a simplistic characterisation of nonapeptides as prosocial regulators of behaviour

X-raying the Beating Heart of a Newborn Star: Rotational Modulation of High-energy Radiation from V1647 Ori

We report a periodicity of ~1 day in the highly elevated X-ray emission from the protostar V1647 Ori during its two recent multiple-year outbursts of mass accretion. This periodicity is indicative of protostellar rotation at near-breakup speed. Modeling of the phased X-ray light curve indicates the high-temperature (~50 MK), X-ray-emitting plasma, which is most likely heated by accretion-induced magnetic reconnection, resides in dense (>~5e10 cm-3), pancake-shaped magnetic footprints where the accretion stream feeds the newborn star. The sustained X-ray periodicity of V1647 Ori demonstrates that such protostellar magnetospheric accretion configurations can be stable over timescales of years.Comment: 26 pages, 10 figure

Distinctive Responsiveness to Stromal Signaling Accompanies Histologic Grade Programming of Cancer Cells

Whether stromal components facilitate growth, invasion, and dissemination of cancer cells or suppress neoplastic lesions from further malignant progression is a continuing conundrum in tumor biology. Conceptualizing a dynamic picture of tumorigenesis is complicated by inter-individual heterogeneity. In the post genomic era, unraveling such complexity remains a challenge for the cancer biologist. Towards establishing a functional association between cellular crosstalk and differential cancer aggressiveness, we identified a signature of malignant breast epithelial response to stromal signaling. Proximity to fibroblasts resulted in gene transcript alterations of >2-fold for 107 probes, collectively designated as Fibroblast Triggered Gene Expression in Tumor (FTExT). The hazard ratio predicted by the FTExT classifier for distant relapse in patients with intermediate and high grade breast tumors was significant compared to routine clinical variables (dataset 1, n = 258, HR – 2.11, 95% CI 1.17–3.80, p-value 0.01; dataset 2, n = 171, HR - 3.07, 95% CI 1.21–7.83, p-value 0.01). Biofunctions represented by FTExT included inflammatory signaling, free radical scavenging, cell death, and cell proliferation. Unlike genes of the ‘proliferation cluster’, which are overexpressed in aggressive primary tumors, FTExT genes were uniquely repressed in such cases. As proof of concept for our correlative findings, which link stromal-epithelial crosstalk and tumor behavior, we show a distinctive differential in stromal impact on prognosis-defining functional endpoints of cell cycle progression, and resistance to therapy-induced growth arrest and apoptosis in low vs. high grade cancer cells. Our experimental data thus reveal aspects of ‘paracrine cooperativity’ that are exclusively contingent upon the histopathologically defined grade of interacting tumor epithelium, and demonstrate that epithelial responsiveness to the tumor microenvironment is a deterministic factor underlying clinical outcome. In this light, early attenuation of epithelial-stromal crosstalk could improve the management of cases prone to be clinically challenging

Muscarinic cholinergic hyperactivity in schizophrenia : relationship to positive and negative symptoms

Based on the implication of increased muscarinic ACh activity in the production of negative symptoms, the association of decreasing cholinergic activity with positive symptoms, and the covariance of positive and negative symptoms in the psychotic phase of schizophrenia, a model of (DA) dopaminergic/(ACh) cholinergic interactions in schizophrenia was recently formulated. It suggests that DA/ACh balance is of central importance in schizophrenic pathophysiology and that muscarinic ACh activity increases in an attempt to maintain this balance in the face of increasing DA activity that occurs in the psychotic phase of the illness. The model further suggests that the muscarinic system exerts a damping influence on the emergence of positive symptoms associated with DA hyperactivity, but that this compensatory increase in muscarinic activity is accompanied by an intensification of negative symptoms. In the present study, we tested two important postulates of this model. We tested the prediction that muscarinic activity is increased in schizophrenia by comparing the effect of biperiden, an antimuscarinic M-1 agent, on REM latency in 12 drug-free schizophrenic inpatients and matched normal controls. We found that biperiden caused a smaller increase in REM latency in schizophrenic patients, suggesting that muscarinic activity is increased in schizophrenia. We tested the prediction that an anticholinergic agent would increase positive symptoms and decrease negative symptoms by studying the effect of 8 mg of biperiden/day for 2 days on positive and negative symptoms (assessed by the BPRS) in 30 medication-free schizophrenic inpatients. Biperiden produced a significant increase in positive symptoms (t = 6.36, DF = 29, P t = -2.05, DF = 29, P < 0.05). These findings suggest that central muscarinic activity is increased in the psychotic phase of schizophrenia and is relevant to the expression of positive and negative symptoms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29522/1/0000609.pd

Highly Variable Extinction and Accretion in the Jet-driving Class I Type Young Star PTF 10nvg (V2492 Cyg, IRAS 20496+4354)

We report extensive new photometry and spectroscopy of the highly variable young stellar object PTF 10nvg including optical and near-infrared time series data as well as mid-infrared and millimeter data. Following the previously reported 2010 rise, during 2011 and 2012 the source underwent additional episodes of brightening and dimming events including prolonged faint states. The observed high-amplitude variations are largely consistent with extinction changes having a 220 day quasi-periodic signal. Spectral evolution includes not only changes in the spectral slope but correlated variation in the prominence of TiO/VO/CO bands and atomic line emission, as well as anticorrelated variation in forbidden line emission which, along with H_2, dominates optical and infrared spectra at faint epochs. Neutral and singly-ionized atomic species are likely formed in an accretion flow and/or impact while the origin of zero-velocity atomic LiI 6707 in emission is unknown. Forbidden lines, including several rare species, exhibit blueshifted emission profiles and likely arise from an outflow/jet. Several of these lines are also seen spatially offset from the continuum source position, presumably in a shocked region of an extended jet. CARMA maps resolve on larger scales a spatially extended outflow in mm-wavelength CO. We attribute the observed photometric and spectroscopic behavior in terms of occultation of the central star as well as the bright inner disk and the accretion/outflow zones that renders shocked gas in the inner part of the jet amenable to observation at the faint epochs. We discuss PTF 10nvg as a source exhibiting both accretion-driven (perhaps analogous to V1647 Ori) and extinction-driven (perhaps analogous to UX Ori or GM Cep) high-amplitude variability phenomena.Comment: accepted to AJ - in press (74 pages