Acute effects of inspiratory pressure threshold loading upon airway resistance in people with asthma

This is the post-print version of the final paper published in Respiratory Physiology & Neurobiology. The published article is available from the link below. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. Copyright @ 2009 Elsevier B.V.Large inspiratory pressures may impart stretch to airway smooth muscle and modify the response to deep inspiration (DI) in asthmatics. Respiratory system resistance (Rrs) was assessed in response to 5 inspiratory manoeuvres using the forced oscillation technique: (a) single unloaded DI; (b) single DI at 25 cmH2O; (c) single DI at 50% maximum inspiratory mouth pressure [MIP]; (d) 30 DIs at 50% MIP; and (e) 30 DIs at 50% MIP with maintenance of normocapnia. Rrs increased after the unloaded DI and the DI at 25 cmH2O but not after a DI at 50% MIP (3.6 ± 1.6 hPa L s−1 vs. 3.6 ± 1.5 hPa L s−1; p = 0.95), 30 DIs at 50% MIP (3.9 ± 1.5 hPa L s−1 vs. 4.2 ± 2.0 hPa L s−1; p = 0.16) or 30 DIs at 50% MIP under normocapnic conditions (3.9 ± 1.5 hPa L s−1 vs. 3.9 ± 1.5 hPa L s−1; p = 0.55). Increases in Rrs in response to DI were attenuated after single and multiple loaded breaths at 50% MIP

Parental stress increases body mass index trajectory in pre-adolescents.

What is already known about this subjectRates of childhood obesity have increased since the mid-1970s. Research into behavioural determinants has focused on physical inactivity and unhealthy diets. Cross-sectional studies indicate an association between psychological stress experienced by parents and obesity in pre-adolescents.What this study addsWe provide evidence of a prospective association between parental psychological stress and increased weight gain in pre-adolescents. Family-level support for those experiencing chronic stress might help promote healthy diet and exercise behaviours in children.ObjectiveWe examined the impact of parental psychological stress on body mass index (BMI) in pre-adolescent children over 4 years of follow-up.MethodsWe included 4078 children aged 5-10 years (90% were between 5.5 and 7.5 years) at study entry (2002-2003) in the Children's Health Study, a prospective cohort study in southern California. A multi-level linear model simultaneously examined the effect of parental stress at study entry on the attained BMI at age 10 and the slope of change across annual measures of BMI during follow-up, controlled for the child's age and sex. BMI was calculated based on objective measurements of height and weight by trained technicians following a standardized procedure.ResultsA two standard deviation increase in parental stress at study entry was associated with an increase in predicted BMI attained by age 10 of 0.287 kg m(-2) (95% confidence interval 0.016-0.558; a 2% increase at this age for a participant of average attained BMI). The same increase in parental stress was also associated with an increased trajectory of weight gain over follow-up, with the slope of change in BMI increased by 0.054 kg m(-2) (95% confidence interval 0.007-0.100; a 7% increase in the slope of change for a participant of average BMI trajectory).ConclusionsWe prospectively demonstrated a small effect of parental stress on BMI at age 10 and weight gain earlier in life than reported previously. Interventions to address the burden of childhood obesity should address the role of parental stress in children

Targeting of cre to the Foxg1 (BF-1) Locus Mediates loxP Recombination in the Telencephalon and Other Developing Head Structures

AbstractThe use of genetics to study the development of the telencephalon and derivatives such as the cerebral cortex has been limited. The telencephalon begins to form midway through gestation, and targeted mutations in genes suspected of playing roles in its development often lead to early phenotypes that preclude analysis of their role at later stages. This problem can be circumvented using a Cre/loxP recombination system. A mouse line was produced in which cre was targeted to the Foxg1 (BF-1) locus, a gene expressed specifically in the telencephalon and discrete head structures. Crosses between Foxg1–Cre mice and three separate loxP reporter mice generated embryos with recombination patterns matching that expected from the normal pattern of Foxg1 expression. Recombination occurs invariably in the telencephalon, anterior optic vesicle, otic vesicle, facial and head ectoderm, olfactory epithelium, mid–hindbrain junction, and pharyngeal pouches. Recombination in some animals also occurs less efficiently in tissues not known to express Foxg1. We show that the genetic background of the parental mice and the loxP target allele can each contribute to differences in the exact pattern of recombination. Collectively, these data show that Foxg1–Cre mice should be useful in the deletion or ectopic expression of any floxed target gene in a Foxg1-like pattern

Proprioceptive changes impair balance control in individuals with chronic obstructive pulmonary disease

Copyright @ 2013 Janssens et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Introduction: Balance deficits are identified as important risk factors for falling in individuals with chronic obstructive pulmonary disease (COPD). However, the specific use of proprioception, which is of primary importance during balance control, has not been studied in individuals with COPD. The objective was to determine the specific proprioceptive control strategy during postural balance in individuals with COPD and healthy controls, and to assess whether this was related to inspiratory muscle weakness. Methods: Center of pressure displacement was determined in 20 individuals with COPD and 20 age/gender-matched controls during upright stance on an unstable support surface without vision. Ankle and back muscle vibration were applied to evaluate the relative contribution of different proprioceptive signals used in postural control. Results: Individuals with COPD showed an increased anterior-posterior body sway during upright stance (p=0.037). Compared to controls, individuals with COPD showed an increased posterior body sway during ankle muscle vibration (p=0.047), decreased anterior body sway during back muscle vibration (p=0.025), and increased posterior body sway during simultaneous ankle-muscle vibration (p=0.002). Individuals with COPD with the weakest inspiratory muscles showed the greatest reliance on ankle muscle input when compared to the stronger individuals with COPD (p=0.037). Conclusions: Individuals with COPD, especially those with inspiratory muscle weakness, increased their reliance on ankle muscle proprioceptive signals and decreased their reliance on back muscle proprioceptive signals during balance control, resulting in a decreased postural stability compared to healthy controls. These proprioceptive changes may be due to an impaired postural contribution of the inspiratory muscles to trunk stability. Further research is required to determine whether interventions such as proprioceptive training and inspiratory muscle training improve postural balance and reduce the fall risk in individuals with COPD.This work was supported by the Research Foundation – Flanders (FWO) grants 1.5.104.03, G.0674.09, G.0598.09N and G.0871.13N

Impaired Postural Control Reduces Sit-to-Stand-to-Sit Performance in Individuals with Chronic Obstructive Pulmonary Disease

Abstract Background: Functional activities, such as the sit-to-stand-to-sit (STSTS) task, are often impaired in individuals with chronic obstructive pulmonary disease (COPD). The STSTS task places a high demand on the postural control system, which has been shown to be impaired in individuals with COPD. It remains unknown whether postural control deficits contribute to the decreased STSTS performance in individuals with COPD. Methods: Center of pressure displacement was determined in 18 individuals with COPD and 18 age/gender-matched controls during five consecutive STSTS movements with vision occluded. The total duration, as well as the duration of each sit, sit-to-stand, stand and stand-to-sit phase was recorded. Results: Individuals with COPD needed significantly more time to perform five consecutive STSTS movements compared to healthy controls (1966 vs. 1364 seconds, respectively; p = 0.001). The COPD group exhibited a significantly longer stand phase (p = 0.028) and stand-to-sit phase (p = 0.001) compared to the control group. In contrast, the duration of the sit phase (p = 0.766) and sit-to-stand phase (p = 0.999) was not different between groups. Conclusions: Compared to healthy individuals, individuals with COPD needed significantly more time to complete those phases of the STSTS task that require the greatest postural control. These findings support the proposition that suboptimal postural control is an important contributor to the decreased STSTS performance in individuals with COPD

Maximal quadratic modules on *-rings

We generalize the notion of and results on maximal proper quadratic modules from commutative unital rings to $\ast$-rings and discuss the relation of this generalization to recent developments in noncommutative real algebraic geometry. The simplest example of a maximal proper quadratic module is the cone of all positive semidefinite complex matrices of a fixed dimension. We show that the support of a maximal proper quadratic module is the symmetric part of a prime $\ast$-ideal, that every maximal proper quadratic module in a Noetherian $\ast$-ring comes from a maximal proper quadratic module in a simple artinian ring with involution and that maximal proper quadratic modules satisfy an intersection theorem. As an application we obtain the following extension of Schm\" udgen's Strict Positivstellensatz for the Weyl algebra: Let $c$ be an element of the Weyl algebra $\mathcal{W}(d)$ which is not negative semidefinite in the Schr\" odinger representation. It is shown that under some conditions there exists an integer $k$ and elements $r_1,...,r_k \in \mathcal{W}(d)$ such that $\sum_{j=1}^k r_j c r_j^\ast$ is a finite sum of hermitian squares. This result is not a proper generalization however because we don't have the bound $k \le d$.Comment: 11 page

Constraining recent lead pollution sources in the North Pacific using ice core stable lead isotopes

Trends and sources of lead (Pb) aerosol pollution in the North Pacific rim of North America from 1850 to 2001 are investigated using a high-resolution (subannual to annual) ice core record recovered from Eclipse Icefield (3017 masl; St. Elias Mountains, Canada). Beginning in the early 1940s, increasing Pb concentration at Eclipse Icefield occurs coevally with anthropogenic Pb deposition in central Greenland, suggesting that North American Pb pollution may have been in part or wholly responsible in both regions. Isotopic ratios (208Pb/207Pb and 206Pb/207Pb) from 1970 to 2001 confirm that a portion of the Pb deposited at Eclipse Icefield is anthropogenic, and that it represents a variable mixture of East Asian (Chinese and Japanese) emissions transported eastward across the Pacific Ocean and a North American component resulting from transient meridional atmospheric flow. Based on comparison with source material Pb isotope ratios, Chinese and North American coal combustion have likely been the primary sources of Eclipse Icefield Pb over the 1970–2001 time period. The Eclipse Icefield Pb isotope composition also implies that the North Pacific mid-troposphere is not directly impacted by transpolar atmospheric flow from Europe. Annually averaged Pb concentrations in the Eclipse Icefield ice core record show no long-term trend during 1970–2001; however, increasing 208Pb/207Pb and decreasing 206Pb/207Pb ratios reflect the progressive East Asian industrialization and increase in Asian pollutant outflow. The post-1970 decrease in North American Pb emissions is likely necessary to explain the Eclipse Icefield Pb concentration time series. When compared with low (lichen) and high (Mt. Logan ice core) elevation Pb data, the Eclipse ice core record suggests a gradual increase in pollutant deposition and stronger trans-Pacific Asian contribution with rising elevation in the mountains of the North Pacific rim

The amylase gene cluster in house mice (Mus musculus) was subject to repeated introgression including the rescue of a pseudogene

Amylase gene clusters have been implicated in adaptive copy number changes in response to the amount of starch in the diet of humans and mammals. However, this interpretation has been questioned for humans and for mammals there is a paucity of information from natural populations

Activation in the COMPTEL double-scattering gamma-ray telescope

Abstract-The COMPTEL gamma-ray telescope has been operating in low Earth orbit for six years, since the launch of the Compton Gamma-Ray Observatory in April 1991. Comparisons of data for different orbits and epochs show evidence of activation on time scales from minutes (27Mg, q,2=9.5 min) to years C2Na, q&.58 yr). The activation is correlated with both the orbital altitude and solar cosmic-ray modulation. Because it requires coincident measurements in two different detectors, COMPTEL is most susceptible to instrumental background events in which two or more photons are produced simultaneously