Pharmacological ablation of the airway smooth muscle layer—Mathematical predictions of functional improvement in asthma

Airway smooth muscle (ASM) plays a major role in acute airway narrowing and reducing ASM thickness is expected to attenuate airway hyper-responsiveness and disease burden. There are two therapeutic approaches to reduce ASM thickness: (a) a direct approach, targeting specific airways, best exemplified by bronchial thermoplasty (BT), which delivers radiofrequency energy to the airway via bronchoscope; and (b) a pharmacological approach, targeting airways more broadly. An example of the less well-established pharmacological approach is the calcium-channel blocker gallopamil which in a clinical trial effectively reduced ASM thickness; other agents may act similarly. In view of established anti-proliferative properties of the macrolide antibiotic azithromycin, we examined its effects in naive mice and report a reduction in ASM thickness of 29% (p <.01). We further considered the potential functional implications of this finding, if it were to extend to humans, by way of a mathematical model of lung function in asthmatic patients which has previously been used to understand the mechanistic action of BT. Predictions show that pharmacological reduction of ASM in all airways of this magnitude would reduce ventilation heterogeneity in asthma, and produce a therapeutic benefit similar to BT. Moreover there are differences in the expected response depending on disease severity, with the pharmacological approach exceeding the benefits provided by BT in more severe disease. Findings provide further proof of concept that pharmacological targeting of ASM thickness will be beneficial and may be facilitated by azithromycin, revealing a new mode of action of an existing agent in respiratory medicine

Carotid arterial remodeling - A maladaptive phenomenon in type 2 diabetes but not in impaired glucose metabolism: The Hoorn Study

Background and Purpose-Deteriorating glucose tolerance is associated with an increased cardiovascular disease (CVD) risk. The underlying mechanisms remain unclear. Arterial remodeling is the change in structural properties through time in response to atherogenic and/or hemodynamic alterations and aims to maintain circumferential wall stress constant (

Asymptotics of the trap-dominated Gunn effect in p-type Ge

We present an asymptotic analysis of the Gunn effect in a drift-diffusion model---including electric-field-dependent generation-recombination processes---for long samples of strongly compensated p-type Ge at low temperature and under dc voltage bias. During each Gunn oscillation, there are different stages corresponding to the generation, motion and annihilation of solitary waves. Each stage may be described by one evolution equation for only one degree of freedom (the current density), except for the generation of each new wave. The wave generation is a faster process that may be described by solving a semiinfinite canonical problem. As a result of our study we have found that (depending on the boundary condition) one or several solitary waves may be shed during each period of the oscillation. Examples of numerical simulations validating our analysis are included.Comment: Revtex, 25 pag., 5 fig., to appear Physica

Intramolecular Force Mapping at Room Temperature

Acquisition of dense, three-dimensional, force fields with intramolecular resolution via noncontact atomic force microscopy (NC-AFM) has yielded enormous progress in our ability to characterize molecular and two-dimensional materials at the atomic scale. To date, intramolecular force mapping has been performed exclusively at cryogenic temperatures, due to the stability afforded by low temperature operation, and as the carbon monoxide functionalization of the metallic scanning probe tip, normally required for submolecular resolution, is only stable at low temperature. In this paper we show that high-resolution, three-dimensional force mapping of a single organic molecule is possible even at room temperature. The physical limitations of room temperature operation are overcome using semiconducting materials to inhibit molecular diffusion and create robust tip apexes, while challenges due to thermal drift are overcome with atom tracking based feedforward correction. Three-dimensional force maps comparable in spatial and force resolution to those acquired at low temperature are demonstrated, permitting a quantitative analysis of the adsorption induced changes in the geometry of the molecule at the picometer level

Deteriorating glucose tolerance status is associated with left ventricular dysfunction - the Hoorn Study

Background: Type 2 diabetes (DM2) is associated with a greater risk of heart failure. The mechanisms underlying this association remain controversial and include diabetes-associated hypertension and obesity, impaired small and large artery function, and a distinct metabolic cardiomyopathy related to hyperglycaemia/hyperinsulinaemia. The proximate causes of heart failure are left ventricular (LV) systolic dysfunction (SDF) and diastolic dysfunction (DDF). We investigated, in a population-based cohort (n=746), the association between glucose tolerance status and SDF and DDF. Methods and results: The study population consisted of 274 individuals with normal glucose metabolism (NGM), 174 with impaired glucose metabolism (IGM) and 298 with DM2 (mean age 68.5 years). All participants underwent an LV echocardiogram. SDF was defined as ejection fraction <55%. DDF was determined by a sum score of peak A velocity (abnormal, ≥97 cm/s), the difference between Apv and Amv duration (≥41 ms), and left atrial volume (≥57 ml), where cut-off values were based upon the 90th percentile in NGM. In addition, we analysed the ratio of early to late diastolic filling (E/A ratio) on a continuous scale using linear regression analyses. The age- and sex-standardised prevalences in NGM, IGM and DM2 were 13, 14 and 30% for SDF, and 26, 36 and 47% for DDF (P(trend) for both <0.001). After adjustment for sex, age, hypertension, body mass index, prior cardiovascular disease and (micro) albuminuria, DM2 was significantly associated with both SDF (odds ratio (95% CI) 2.04 (1.24 to 3.36)) and DDF (2.42 (1.63 to 3.60)) (90th percentile definition). This was also true for the analyses with the E/A ratio on a continuous scale (regression coefficient β (95% CI) -0.05 (-0.09 to -0.01). After adjustment for sex, age, hypertension, body mass index, prior cardiovascular disease and (micro) albuminuria IGM was not significantly associated with SDF (odds ratio (95% CI) 1.04 (0.58 to 1.88)) or DDF (1.33 (0.86 to 2.06)) using the definition based upon the 90th percentile. However, IGM was significantly associated with DDF if the E/A ratio was analysed on a continuous scale (regression coefficient β (95% CI) -0.05 (-0.10 to -0.01). Additional adjustment for brachial artery flow-mediated vasodilation or arterial stiffness, as measures of large artery function, did not materially alter the results. Hyperglycaemia and hyperinsulinaemia together explained ∼30% of the association of DM2 with SDF and ∼40% of that with DDF. Conclusion: DM2 is independently associated with a 2.0-fold greater risk of SDF and a 2.4-fold greater risk of DDF. IGM was not associated with SDF, and the association with DDF was limited to the E/A ratio. These observations may therefore explain the increased risk of systolic and diastolic heart failure in elderly individuals with DM2

Arterial stiffness increases with deteriorating glucose tolerance status - The Hoorn Study

Background - Type 2 diabetes (DM-2) and impaired glucose metabolism (IGM) are associated with an increased cardiovascular disease risk. In nondiabetic individuals, increased arterial stiffness is an important cause of cardiovascular disease. Associations between DM-2 and IGM and arterial stiffness have not been systematically investigated. Methods and Results - In a population-based cohort (n=747; 278 with normal glucose metabolism, 168 with IGM, and 301 with DM-2; mean age, 68.5 years), arterial stiffness was ultrasonically estimated by distensibility and compliance of the carotid, femoral, and brachial arteries and by the carotid elastic modulus. After adjustment for age, sex, and mean arterial pressure, DM-2 was associated with increased carotid, femoral, and brachial stiffness, whereas IGM was associated only with increased femoral and brachial stiffness. Carotid but not femoral or brachial stiffness increased from IGM to DM-2. Standardized βs (95% CI) for IGM and DM-2, compared with normal glucose metabolism, were -0.06 (-0.23 to 0.10) and -0.37 (-0.51 to -0.23) for carotid distensibility; -0.02 (-0.18 to 0.18) and -0.25 (-0.40 to -0.09) for carotid compliance; -0.05 (-0.23 to 0.13) and 0.25 (0.10 to 0.40) for carotid elastic modulus; -0.70 (-0.89 to -0.51) and -0.67 (-0.83 to -0.52) for femoral distensibility; and -0.62 (-0.80 to -0.44) and -0.79 (-0.94 to -0.63) for femoral compliance. The brachial artery followed a pattern similar to that of the femoral artery. Increases in stiffness indices were explained by decreases in distension, increases in pulse pressure, an increase in carotid intima-media thickness, and, for the femoral artery, a decrease in diameter. Hyperglycemia or hyperinsulinemia explained only 30% of the arterial changes associated with glucose tolerance. Adjustment for conventional cardiovascular risk factors did not affect these findings. Conclusions - IGM and DM-2 are associated with increased arterial stiffness. An important part of the increased stiffness occurs before the onset of DM-2 and is explained neither by conventional cardiovascular risk factors nor by hyperglycemia or hyperinsulinemia

Increased central artery stiffness in impaired glucose metabolism and type 2 diabetes - The Hoorn study

Impaired glucose metabolism (IGM) and type 2 diabetes (DM-2) are associated with high cardiovascular disease risk. Increases in peripheral and central artery stiffness may represent pathophysiologic pathways through which glucose tolerance status leads to cardiovascular disease. Peripheral artery stiffness increases with deteriorating glucose tolerance status, whereas this trend remains unclear for central artery stiffness. Therefore, we investigated the associations between glucose tolerance status and estimates of central arterial stiffness. We performed a population-based study of 619 individuals (normal glucose metabolism, n=261; IGM, n=170; and DM-2, n=188) and assessed central artery stiffness by measuring total systemic arterial compliance, aortic pressure augmentation index, and carotid-femoral transit time. After adjustment for sex, age, heart rate, height, body mass index, and mean arterial pressure, DM-2 was associated with decreased total systemic arterial compliance, increased aortic augmentation index, and decreased carotid-femoral transit time. IGM was borderline significantly associated with decreased total systemic arterial compliance. Respective regression coefficients (95% confidence intervals) for IGM and DM-2 compared with normal glucose metabolism were -0.05 (-0.11 to 0.01) and -0.13 (-0.19 to -0.07) mL/mm Hg for total system carterial compliance; 1.1 (-0.2 to 2.5) and 1.6 (0.2 to 3.0) percentage points for aortic augmentation index; and -0.85 (-5.20 to 3.49) and -4.95 (-9.41 to -0.48) ms for carotid-femoral transit time. IGM and DM-2 are associated with increased central artery stiffness, which is more pronounced in DM-2. Deteriorating glucose tolerance is associated with increased central and peripheral arterial stiffness, which may partly explain why both DM-2 and IGM are associated with increased cardiovascular risk

S-Adenosylmethionine and 5-Methyltetrahydrofolate are associated with endothelial function after controlling for confounding by homocysteine: the Hoorn study

): 48.57 microm (21.16; 75.98) and -32.15 microm (-59.09; -5.20), but high homocysteine was not (-15.11 microm (-42.99; 12.78). High SAM and low 5-MTHF were also significantly associated with high and low NMD, respectively. NMD explained the association of 5-MTHF with FMD but not of SAM. No interactions were observed for diabetes or cardiovascular risk factors. CONCLUSIONS: In this elderly population, both SAM and 5-MTHF are associated with endothelial and smooth muscle cell function. The effect of homocysteine on endothelial function is relatively small compared with SAM and 5-MTHF. The relative impact of SAM, 5-MTHF, and homocysteine, and the mechanisms through which these moieties may affect endothelial and smooth muscle cell function need clarification. Both SAM and 5-MTHF are associated with endothelial and smooth muscle cell function whereas the effect of homocysteine is relatively small compared with SAM and 5-MTH

Mirror Energy Differences at Large Isospin Studied through Direct Two-Nucleon Knockout

The first spectroscopy of excited states in Ni52 (Tz=-2) and Co51 (Tz=-3/2) has been obtained using the highly selective two-neutron knockout reaction. Mirror energy differences between isobaric analogue states in these nuclei and their mirror partners are interpreted in terms of isospin nonconserving effects. A comparison between large-scale shell-model calculations and data provides the most compelling evidence to date that both electromagnetic and an additional isospin nonconserving interactions for J=2 couplings, of unknown origin, are required to obtain good agreement. � 2013 American Physical Society