bluuebunny/crossref_metadata_2025 huggingface dataset:
Protective Role of Angiopoietin-1 in Endotoxic Shock
Authors: Witzenbichler Bernhard , Westermann Dirk , Knueppel Sabine , Schultheiss Heinz-Peter , Tschope Carsten
Published: December 2004

Background—

Angiopoietin-1 (Ang1) plays an essential role in embryonic vasculature development, protects the adult peripheral vasculature from leakage, and has antiinflammatory properties. Because endotoxin-induced shock is a condition with microvascular leakage resulting from inflammation, we examined the potential therapeutic benefit of Ang1 in a murine model of lipopolysaccharide (LPS)-induced endotoxic shock.

Methods and Results—

To induce endotoxic shock, LPS was injected intraperitoneally into C57BL/6 mice. Half of the mice received an intravenous application of 1.0×10
9
plaque-forming units of an adenoviral construct expressing human Ang1 (AdhAng1); in the other half an identical vector expressing green fluorescent protein (AdGFP) was injected as a control. In the AdhAng1-treated mice, hepatic transfection and high expression of circulating Ang1 protein were observed. Whereas in LPS-treated control mice, hemodynamic function was severely depressed 12 hours after LPS injection (decrease of blood pressure from 91±3 to 49±7 mm Hg, d
P
/d
t
max
from 7284±550 to 2699±233 mm Hg/s, cardiac output from 11.3±1.2 to 2.8±0.8 mL/min;
P
<0.0005), in LPS-treated AdhAng1 mice blood pressure fell only to 76±3 mm Hg, d
P
/d
t
max
to 5091±489 mm Hg/s, and cardiac output to 6.7±1.4 mL/min (
P
<0.05). This resistance to LPS-induced hemodynamic changes was reflected by an improved Kaplan-Meier survival rate of the AdhAng1 mice. Histological analysis revealed that lung injury after LPS injection was markedly attenuated in AdhAng1 mice. In addition, LPS-induced increase in lung water content and pulmonary myeloperoxidase activity was significantly reduced. Furthermore, LPS-induced increases in the expression level of vascular cell adhesion molecule-1, intracellular adhesion molecule-1, and E-selectin protein in the lungs were markedly lower in AdhAng1 mice than in control mice. Finally, in the mice overexpressing Ang1, pulmonary endothelial NO synthase (eNOS) expression and activity remained preserved after LPS challenge, providing evidence that the beneficial effect of Ang1 in endotoxic shock is mediated by eNOS-derived NO.

Conclusions—

Our study demonstrates an improved mortality rate in mice with endotoxic shock pretreated with an adenoviral construct encoding Ang1. The enhanced survival rate induced by Ang1 was accompanied by an improvement in hemodynamic function, reduced lung injury, a lower expression of inflammatory adhesion molecules, and preserved eNOS activity in the lung tissue. Ang1 may therefore have utility as an adjunctive agent for the treatment of septic shock condition.
Functional Variant of
CYP4A11
20-Hydroxyeicosatetraenoic Acid Synthase Is Associated With Essential Hypertension
Authors: Gainer James V. , Bellamine Aouatef , Dawson Elliott P. , Womble Kristie E. , Grant Sarah W. , Wang Yarong , Cupples L. Adrienne , Guo Chao-Yu , Demissie Serkalem , O’Donnell Christopher J. , Brown Nancy J. , Waterman Michael R. , Capdevila Jorge H.
Published: December 2004

Background—

The CYP4A11 arachidonic acid monooxygenase oxidizes endogenous arachidonic acid (AA) to 20-hydroxyeicosatetraenoic acid (20-HETE), a metabolite with renovascular and tubular functions. Mice with targeted disruption of
Cyp4a14
, a murine homologue of
CYP4A11
, have severe hypertension. We combined molecular and biochemical approaches to identify a functional variant of the
CYP4A11
20-HETE synthase and determine its association with hypertensive status in 2 independent human populations.

Methods and Results—

A thymidine-to-cytosine polymorphism at nucleotide 8590 resulted in a phenylalanine-to-serine substitution at amino acid 434. Expression of cDNA with serine 434 resulted in a protein with a significantly reduced AA and lauric acid metabolizing activity. In a population of 512 whites from Tennessee, the age, body mass index, and gender-adjusted OR of having hypertension attributable to the 8590C variant was 2.31 (95% CI 1.41 to 3.78) compared with the reference 8590TT genotype. In subjects from the Framingham Heart Study, the adjusted ORs of hypertension associated with the 8590C variant were 1.23 (CI 0.94 to 1.59; n=1538) in all subjects and 1.33 (CI 1.01 to 1.77; n=1331) when subjects with diabetes were excluded. No association of the variant with hypertension was detected in a population of 120 blacks.

Conclusions—

We identified a variant of the human
CYP4A11
(T8590C) that encodes for a monooxygenase with reduced 20-HETE synthase activity. The association of the T8590C variant with hypertension supports its role as a polygenic determinant of blood pressure control in humans, and results obtained from the large population database suggest that the relevance of the variant may vary according to hypertension comorbidity.
Elevated Levels of High-Sensitivity C-Reactive Protein and Serum Amyloid-A Late After Kawasaki Disease
Authors: Mitani Yoshihide , Sawada Hirofumi , Hayakawa Hidetoshi , Aoki Kenzo , Ohashi Hiroyuki , Matsumura Masahiko , Kuroe Kenji , Shimpo Hideto , Nakano Masataka , Komada Yoshihiro
Published: December 2004

Background—

Coronary sequelae that persist after Kawasaki disease (KD) have been associated with obstructive changes of the lesions and coronary vascular events in adolescents and young adults. However, little is known about the association between sequelae late after KD and inflammatory markers, which are potential mediators and markers for atherogenesis.

Methods and Results—

Cross-sectional study was performed to test the hypothesis that coronary sequelae are associated with elevated levels of inflammatory markers in patients late after KD (mean time interval after the onset, 10 years, 10 months). Levels of high-sensitivity C-reactive protein (CRP), serum amyloid-A (SAA), interleukin-6, and soluble intercellular adhesion molecule-1 were measured in the 4 groups (n=80): the referent group (n=15) and KD subgroups with normal coronary arteries from the onset (n=27); with regressed aneurysms (n=18); and with coronary artery lesions, such as persistent aneurysms, stenosis, and occlusion (n=20). CRP levels were significantly elevated in a KD subgroup with coronary artery lesions compared with the referent or other KD subgroups, as analyzed by ANOVA and ANCOVA after adjustment for a confounding factor body mass index. Levels of CRP, SAA, and interleukin-6 were positively correlated. Stepwise regression and logistic regression analyses support the association between the persistence of coronary artery lesions and the levels of CRP and SAA.

Conclusions—

Results demonstrate that the persistence of coronary lesions late after KD was independently associated with levels of CRP and SAA, suggesting that inflammation may be a novel functional aspect of coronary artery diseases late after KD.
Functional Integration of Electrically Active Cardiac Derivatives From Genetically Engineered Human Embryonic Stem Cells With Quiescent Recipient Ventricular Cardiomyocytes
Authors: Xue Tian , Cho Hee Cheol , Akar Fadi G. , Tsang Suk-Ying , Jones Steven P. , Marbán Eduardo , Tomaselli Gordon F. , Li Ronald A.
Published: December 2004

Background—

Human embryonic stem cells (hESCs) derived from blastocysts can propagate indefinitely in culture while maintaining pluripotency, including the ability to differentiate into cardiomyocytes (CMs); therefore, hESCs may provide an unlimited source of human CMs for cell-based therapies. Although CMs can be derived from hESCs ex vivo, it remains uncertain whether a functional syncytium can be formed between donor and recipient cells after engraftment.

Methods and Results—

Using a combination of electrophysiological and imaging techniques, here we demonstrate that electrically active, donor CMs derived from hESCs that had been stably genetically engineered by a recombinant lentivirus can functionally integrate with otherwise-quiescent, recipient, ventricular CMs to induce rhythmic electrical and contractile activities in vitro. The integrated syncytium was responsive to the β-adrenergic agonist isoproterenol as well as to other pharmacological agents such as lidocaine and ZD7288. Similarly, a functional hESC-derived pacemaker could be implanted in the left ventricle in vivo. Detailed optical mapping of the epicardial surface of guinea pig hearts transplanted with hESC-derived CMs confirmed the successful spread of membrane depolarization from the site of injection to the surrounding myocardium.

Conclusions—

We conclude that electrically active, hESC-derived CMs are capable of actively pacing quiescent, recipient, ventricular CMs in vitro and ventricular myocardium in vivo. Our results may lead to an alternative or a supplemental method for correcting defects in cardiac impulse generation, such as cell-based pacemakers.
Cardiac Mortality Is Higher Around Christmas and New Year’s Than at Any Other Time
Authors: Phillips David P. , Jarvinen Jason R. , Abramson Ian S. , Phillips Rosalie R.
Published: December 2004

Background—

Research published in
Circulation
has shown that cardiac mortality is highest during December and January. We investigated whether some of this spike could be ascribed to the Christmas/New Year’s holidays rather than to climatic factors.

Methods and Results—

We fitted a locally weighted polynomial regression line to daily mortality to estimate the number of deaths expected during the holiday period, using the null hypothesis that natural-cause mortality is unaffected by the Christmas/New Year’s holidays. We then compared the number of deaths expected during the holiday period, given the null hypothesis, with the number of deaths observed. For cardiac and noncardiac diseases, a spike in daily mortality occurs during the Christmas/New Year’s holiday period. This spike persists after adjusting for trends and seasons and is particularly large for individuals who are dead on arrival at a hospital, die in the emergency department, or die as outpatients. For this group during the holiday period, 4.65% (±0.30%; 95% CI, 4.06% to 5.24%) more cardiac and 4.99% (±0.42%; 95% CI, 4.17% to 5.81%) more noncardiac deaths occur than would be expected if the holidays did not affect mortality. Cardiac mortality for individuals who are dead on arrival, die in the emergency department, or die as outpatients peaks at Christmas and again at New Year’s. These twin holiday spikes also are conspicuous for noncardiac mortality. The excess in holiday mortality is growing proportionately larger over time, both for cardiac and noncardiac mortality.

Conclusions—

Our findings suggest that the Christmas/New Year’s holidays are a risk factor for cardiac and noncardiac mortality. There are multiple explanations for this association, including the possibility that holiday-induced delays in seeking treatment play a role in producing the twin holiday spikes.
Endothelial Cell Activation in Patients With Decompensated Heart Failure
Authors: Colombo Paolo C. , Banchs Javier E. , Celaj Sulejman , Talreja Ashok , Lachmann Justine , Malla Shailesh , DuBois Nicholas B. , Ashton Anthony W. , Latif Farhana , Jorde Ulrich P. , Ware J. Anthony , LeJemtel Thierry H.
Published: December 2004

Background—

Vascular endothelial functions, other than nitric oxide (NO)–mediated control of vasomotor tone, are poorly characterized in patients with chronic heart failure (CHF). Veins and arteries are exposed to the same circulating proinflammatory mediators in patients with CHF. The present study tested whether endothelial cell activation occurs in veins of patients with decompensated CHF and whether activation, if present, subsides with return to a clinically compensated state.

Methods and Results—

Fifteen patients with decompensated CHF requiring transient inotropic support and 6 age-matched, healthy controls were studied. Endothelial cells and blood were collected from a forearm vein, and brachial artery flow–mediated dilation (FMD) was measured before and 24 hours after discontinuation of short-term inotropic therapy, when patients had returned to a steady compensated state. Nitrotyrosine immunoreactivity (an intracellular marker of oxidative stress), cyclooxygenase-2 (COX-2), and inducible NO synthase (iNOS) expression were significantly higher in venous endothelial cells of patients in clinical decompensation when compared with healthy subjects. Return to a compensated state resulted in a significant reduction in nitrotyrosine immunoreactivity, COX-2, and iNOS expression. Concomitantly, a significant increase in FMD and a decline in plasma total 8-isoprostane and bicycloprostaglandin E
2
levels were observed. Venous endothelial NOS expression was unaffected by clinical decompensation.

Conclusions—

Clinical decompensation in CHF is associated with activation of the venous endothelium. Return to a compensated state after short-term inotropic therapy results in a significant reduction in endothelial nitrotyrosine formation, COX-2, and iNOS expression.
Cardioprotection by ε-Protein Kinase C Activation From Ischemia
Authors: Inagaki Koichi , Begley Rebecca , Ikeno Fumiaki , Mochly-Rosen Daria
Published: December 2004

Background—

We previously showed that a selective activator peptide of ε-protein kinase C (PKC), ψεRACK, conferred cardioprotection against ischemia-reperfusion when delivered ex vivo before the ischemic event. Here, we tested whether in vivo continuous systemic delivery of ψεRACK confers sustained cardioprotection against ischemia-reperfusion in isolated mouse hearts and whether ψεRACK treatment reduces infarct size or lethal arrhythmias in porcine hearts in vivo.

Methods and Results—

After ψεRACK was systemically administered in mice either acutely or continuously, hearts were subjected to ischemia-reperfusion in an isolated perfused model. Whereas ψεRACK-induced cardioprotection lasted 1 hour after a single intraperitoneal injection, continuous treatment with ψεRACK induced a sustained preconditioned state during the 10 days of delivery. There was no desensitization to the therapeutic effect, no downregulation of εPKC, and no adverse effects after sustained ψεRACK delivery. Porcine hearts were subjected to ischemia-reperfusion in vivo, and ψεRACK was administered by intracoronary injection during the first 10 minutes of ischemia. ψεRACK treatment reduced infarct size (34±2% versus 14±1%, control versus ψεRACK) and resulted in fewer cases of ventricular fibrillation during ischemia-reperfusion (87.5% versus 50%, control versus ψεRACK).

Conclusions—

The εPKC activator ψεRACK induced cardioprotection both in vivo and ex vivo, reduced the incidence of lethal arrhythmia during ischemia-reperfusion, and did not cause desensitization or downregulation of εPKC after sustained delivery. Thus, ψεRACK may be useful for patients with ischemic heart disease. In addition, the ψεRACK peptide should be a useful pharmacological agent for animal studies in which systemic and sustained modulation of εPKC in vivo is needed.
Thiazide-Like Diuretics Attenuate Agonist-Induced Vasoconstriction by Calcium Desensitization Linked to Rho Kinase
Authors: Zhu Zhiming , Zhu Shanjun , Liu Daoyan , Cao Tingbing , Wang Lijuan , Tepel Martin
Published: December 2004

Lowering blood pressure using thiazide-like diuretics, including chlorthalidone and hydrochlorothiazide, has been proven to be effective in clinical studies. However, the mechanisms by which thiazide-like diuretics lower blood pressure are still poorly understood. To evaluate whether thiazide-like diuretics cause calcium desensitization in smooth muscle cells, we measured their effects on agonist-induced increase of blood pressure in Wistar rats in vivo and on agonist-induced vasoconstriction of aortic rings, DNA synthesis, and protein synthesis, RhoA, Rho kinase, and intracellular calcium in vascular smooth muscle cells in vitro. Thiazide-like diuretics significantly attenuated angiotensin II–induced or norepinephrine-induced increase of systolic blood pressure in rats. Thiazide-like diuretics inhibited agonist-induced vasoconstriction of aortic rings in a concentration-dependent manner in the presence and absence of endothelium. The inhibitory effects of thiazide-like diuretics were similar to that of the specific Rho kinase inhibitor Y27632. RT-PCR and immunoblotting showed that RhoA and Rho kinase were significantly reduced in vascular smooth muscle cells after administration of thiazide-like diuretics. In contrast, thiazide-like diuretics did not affect protein tyrosine phosphatase-2 (SHP-2) expression. Agonist-induced changes of intracellular calcium were not affected by thiazide-like diuretics. The study indicates that thiazide-like diuretics inhibit agonist-induced vasoconstriction by calcium desensitization in smooth muscle cells linked to the Rho–Rho kinase pathway.
Simulation of Effects of Atmospheric Aerosols on Deep Turbulent Convective Clouds Using a Spectral Microphysics Mixed-Phase Cumulus Cloud Model. Part II: Sensitivity Study
Authors: Khain A. , Pokrovsky A.
Published: December 2004

Effects of different size distributions of cloud condensational nuclei (CCN) on the evolution of deep convective clouds under dry unstable continental thermodynamic conditions are investigated using the spectral microphysics Hebrew University Cloud Model (HUCM). In particular, high supercooled water content just below the level of homogeneous freezing, as well as an extremely high concentration of ice crystals above the level, observed recently by Rosenfeld and Woodley at the tops of growing clouds in Texas, were successfully reproduced.

Numerical experiments indicate a significant decrease in accumulated precipitation in smoky air. The fraction of warm rain in the total precipitation amount increases with a decrease in the CCN concentration. The fraction is low in smoky continental air and is dominating in clean maritime air. As warm rain is a smaller fraction of total precipitation, the decrease in the accumulated rain amount in smoky air results mainly from the reduction of melted precipitation.

It is shown that aerosols significantly influence cloud dynamics leading to the elevation of the level of precipitating particle formation. The falling down of these particles through dry air leads to a loss in precipitation. Thus, close coupling of microphysical and dynamical aerosol effects leads to the rain suppression from clouds arising in dry smoky air.

The roles of freezing, CCN penetration through lateral cloud boundaries, and turbulent effects on cloud particles collisions are evaluated.

Results, obtained using spectral microphysics, were compared with those obtained using two well-known schemes of bulk parameterization. The results indicate that the bulk parameterization schemes do not reproduce well the observed cloud microstructure.
Solar Radiation Budget from the MRI Radiometers for Clear and Cloudy Air Columns within ARESE II
Authors: Asano Shoji , Uchiyama Akihiro , Yamazaki Akihiro , Kuchiki Katsuyuki
Published: December 2004

As an international collaborative research activity within the Japanese Cloud-Climate Study (JACCS) program, the authors participated in the second Atmospheric Radiation Measurement (ARM) Enhanced Shortwave Experiment (ARESE II) using the Meteorological Research Institute (MRI) radiometers. This paper describes results of ARESE II, as well as specifications and calibration of the MRI radiometers. The solar radiation budget for 2 days of typical clear sky (27 February and 20 March 2000) and overcast sky (3 and 21 March 2000) has been analyzed using spatially collocated, total-band solar irradiances measured by the MRI pyranometers (Kipp & Zonen CM21). These were installed on a Twin Otter aircraft, and deployed at the ARM Southern Great Planes Central Facility site. On average, the clear-sky and overcast-sky air columns between the surface and the Twin Otter flight level of 7 km absorbed about 13% ± 2% and 20% ± 3%, respectively, of the total-band solar radiation incident on the column top. The measured solar radiation budgets agree well with those computed for models of clear and cloudy atmospheres. The present results indicate no evidence of anomalous solar absorption for either the clear- or cloudy-sky cases. It is suggested that about half of the observed absorption enhancement of 7% for the overcast-sky cases could be caused by the presence of larger water vapor, compared with the clear-sky cases, and that the other half could be caused by increased absorption within and above the rather low cloud layers.
Mixing Layer Formation near the Tropopause Due to Gravity Wave–Critical Level Interactions in a Cloud-Resolving Model
Authors: Moustaoui Mohamed , Joseph Binson , Teitelbaum Hector
Published: December 2004

A plausible mechanism for the formation of mixing layers in the lower stratosphere above regions of tropical convection is demonstrated numerically using high-resolution, two-dimensional (2D), anelastic, nonlinear, cloud-resolving simulations. One noteworthy point is that the mixing layer simulated in this study is free of anvil clouds and well above the cloud anvil top located in the upper troposphere. Hence, the present mechanism is complementary to the well-known process by which overshooting cloud turrets causes mixing within stratospheric anvil clouds. The paper is organized as a case study verifying the proposed mechanism using atmospheric soundings obtained during the Central Equatorial Pacific Experiment (CEPEX), when several such mixing layers, devoid of anvil clouds, had been observed. The basic dynamical ingredient of the present mechanism is (quasi stationary) gravity wave–critical level interactions, occurring in association with a reversal of stratospheric westerlies to easterlies below the tropopause region. The robustness of the results is shown through simulations at different resolutions. The insensitivity of the qualitative results to the details of the subgrid scheme is also evinced through further simulations with and without subgrid mixing terms. From Lagrangian reconstruction of (passive) ozone fields, it is shown that the mixing layer is formed kinematically through advection by the resolved-scale (nonlinear) velocity field.
Effects of Large Eddies on the Structure of the Marine Boundary Layer under Strong Wind Conditions
Authors: Ginis Isaac , Khain Alexander P. , Morozovsky Elena
Published: December 2004

A model of the atmospheric boundary layer (BL) is presented that explicitly calculates a two-way interaction of the background flow and convective motions. The model is utilized for investigation of the formation of large eddies (roll vortices) and their effects on the structure of the marine boundary layer under conditions resembling those of tropical cyclones. It is shown that two main factors controlling the formation of large eddies are the magnitude of the background wind speed and air humidity, determining the cloud formation and latent heat release. When the wind speed is high enough, a strong vertical wind shear develops in the lower part of the BL, which triggers turbulent mixing and the formation of a mixed layer. As a result, the vertical profiles of velocity, potential temperature, and mixing ratio in the background flow are modified to allow for the development of large eddies via dynamic instability. Latent heat release in clouds was found to be the major energy source of large eddies. The cloud formation depends on the magnitude of air humidity.

The most important manifestation of the effects of large eddies is a significant increase of the near-surface wind speed and evaporation from the sea surface. For strong wind conditions, the increase of the near-surface speed can exceed 10 m s−1 and evaporation from the sea surface can double. These results demonstrate an important role large eddies play in the formation of BL structure in high wind speeds. Inclusion of these effects in the BL parameterizations of tropical cyclone models may potentially lead to substantial improvements in the prediction of storm intensity.
A New Heuristic Lagrangian Marine Boundary Layer Cloud Model
Authors: Park Sungsu , Leovy Conway B. , Rozendaal Margaret A.
Published: December 2004

A new heuristic model of stratocumulus cloudiness in the inversion-capped marine boundary layer is developed and tested. The essential ingredient is a new method for predicting the statistical distribution of temperature and specific humidity at the inversion base under partially decoupled conditions along steady-state marine boundary layer (MBL) trajectories. MBL decoupling is parameterized as an increasing function of the height difference between the inversion base and lifting condensation level (LCL) of the mixed-layer air. Required inputs are sea surface temperature (SST), free air (above inversion) temperature and humidity, subsidence velocity, and mean boundary layer wind speed. Upstream boundary conditions must also be specified but have little influence at sufficient downstream distances (>2000 km).

The model is applied to the cold advection regime of the northeastern subtropical Pacific and to both warm and cold advection regimes of the eastern equatorial Pacific Ocean. The model is conceptually simple and avoids explicit calculation of several important physical processes. Nevertheless, it is at least qualitatively successful in predicting both the climatological mean properties and climate anomaly variations of MBL stratocumulus in both regions. These results suggest that, regardless of other properties, successful MBL stratocumulus models will need to accurately predict inversion base height and the LCL and they will have to account for downstream memory effects.
Simulation of Effects of Atmospheric Aerosols on Deep Turbulent Convective Clouds Using a Spectral Microphysics Mixed-Phase Cumulus Cloud Model. Part I: Model Description and Possible Applications
Authors: Khain A. , Pokrovsky A. , Pinsky M. , Seifert A. , Phillips V.
Published: December 2004

An updated version of the spectral (bin) microphysics cloud model developed at the Hebrew University of Jerusalem [the Hebrew University Cloud Model (HUCM)] is described. The model microphysics is based on the solution of the equation system for size distribution functions of cloud hydrometeors of seven types (water drops, plate-, columnar-, and branch-like ice crystals, aggregates, graupel, and hail/frozen drops) as well as for the size distribution function of aerosol particles playing the role of cloud condensational nuclei (CCN). Each size distribution function contains 33 mass bins.

The conditions allowing numerical reproduction of a narrow droplet spectrum up to the level of homogeneous freezing in deep convective clouds developed in smoky air are discussed and illustrated using as an example Rosenfeld and Woodley's case of deep Texas clouds.

The effects of breakup on precipitation are illustrated by the use of a new collisional breakup scheme. Variation of the microphysical structure of a melting layer is illustrated by using the novel melting procedure.

It is shown that an increase in the aerosol concentration leads to a decrease in precipitation from single clouds both under continental and maritime conditions. To provide similar precipitation, a cloud developed in smoky air should have a higher top height. The mechanisms are discussed through which aerosols decrease precipitation efficiency. It is shown that aerosols affect the vertical profile of the convective heating caused by latent heat release.
Mechanisms of Up-Valley Winds
Authors: Rampanelli Gabriele , Zardi Dino , Rotunno Richard
Published: December 2004

The basic physical mechanisms governing the daytime evolution of up-valley winds in mountain valleys are investigated using a series of numerical simulations of thermally driven flow over idealized three-dimensional topography. The three-dimensional topography used in this study is composed of two, two-dimensional topographies: one a slope connecting a plain with a plateau and the other a valley with a horizontal floor. The present two-dimensional simulations of the valley flow agree with results of previous investigations in that the heated sidewalls produce upslope flows that require a compensating subsidence in the valley core bringing down potentially warmer air from the stable free atmosphere. In the context of the three-dimensional valley–plain simulations, the authors find that this subsidence heating in the valley core is the main contributor to the valley– plain temperature contrast, which, under the hydrostatic approximation, is the main contributor to the valley– plain pressure difference that drives the up-valley wind.
Living wages and the ‘making work pay’ strategy
Authors: Grover Chris
Published: December 2004

Poverty among workers is a perennial problem. Recently there has been much interest in the idea of living wages. As mechanisms to increase wages above the ‘poverty line’, living wages present an alternative to New Labour’s ‘making work pay’ strategy; a combination of minimum wage regulation and means-tested, in-work relief. Through a comparison of living wages and the ‘making work pay’ strategy this paper critically examines both by focusing upon the aims of the two strategies, their ability to deliver higher incomes to workers and their families, and the assumptions upon which the two strategies are based. The paper demonstrates that while the ‘making work pay’ strategy is more sensitive to need than living wages, outside of wider changes in the social relations of capital and gender, the two strategies are similar in buttressing capitalism and institutionalizing stereotypes of women as dependants and carers.
Employability and problem drug users
Authors: Kemp Peter A. , Neale Joanne
Published: December 2004

The New Labour government in Britain has introduced a major programme of welfare to work, known as the New Deal, which aims to help unemployed and economically inactive people into paid work. Although welfare to work programmes may be appropriate for those who are more or less job ready, it is less clear that they are suitable for hard-to-help groups with multiple disadvantages. This article draws on new survey evidence from Scotland to question the suitability of welfare to work for problem drug users. It demonstrates that many people using drug treatment services suffer from a range of serious personal, health, lifestyle, and other problems that would need to be addressed before they are in a position either to complete welfare to work programmes successfully or to take up and retain paid employment.
The privatization of council housing
Authors: Ginsburg Norman
Published: December 2004

Direct provision of affordable rented housing by local authorities is fast disappearing in Britain with the transfer of homes to quasi-private landlords. This article describes the process as it has unfolded since the late 1980s, and suggests that it imposes greater long-term risks on former council tenants and town hall staff, while also generating considerable costs for the taxpayer. The process also excludes the many tenants who either reject transfer or are not given the choice, and therefore exacerbates inequalities. There are immediate and substantial benefits for transferred tenants, but this has to be weighed against the loss of a municipal public service.
Effects of Administration of Exogenous Growth Factors on Biomechanical Properties of the Elongation-type Anterior Cruciate Ligament Injury with Partial Laceration
Authors: Kondo Eiji , Yasuda Kazunori , Yamanaka Masanori , Minami Akio , Tohyama Harukazu
Published: December 2004

Background

No studies have been conducted to clarify the in vivo effect of growth factor application on healing in the injured anterior cruciate ligament.

Hypothesis

Administration of exogenous growth factors significantly increases the structural properties of the injured anterior cruciate ligament.

Study Design

Controlled laboratory study.

Methods

Thirty-six rabbits were randomly divided into 4 groups of 9 animals each after an overstretched injury was made in the right anterior cruciate ligament. In group 1, no treatment was applied around the injured anterior cruciate ligament. In group 2, 0.2 mL fibrin sealant was applied around it. In group 3, 4 ng transforming growth factor–β1 mixed with 0.2 mL fibrin sealant was applied. In group 4, 20 μg platelet-derived growth factor–BB mixed with 0.2 mL fibrin sealant was applied. Each rabbit was sacrificed at 12 weeks after the surgery. In addition, 9 knees randomly harvested from all the left knees were used to obtain normal control data. The femur–anterior cruciate ligament–tibia complex specimens were biomechanically and histologically evaluated.

Results

Concerning the maximum load and the stiffness, group 3 was significantly greater than groups 1 and 2, whereas there were no significant differences among groups 1, 2, and 4. Groups 1, 2, 3, and 4 were significantly lower than the control group.

Conclusions

The application of 4 ng transforming growth factor–β1 significantly enhances healing in the injured anterior cruciate ligament.

Clinical Relevance

Administration of certain growth factors is of value to be studied as one of the future therapeutic options for the overstretched anterior cruciate ligament injury.
Bone Stress Injuries in Asymptomatic Elite Recruits
Authors: Kiuru Martti J. , Niva Maria , Reponen Anssi , Pihlajamäki Harri K.
Published: December 2004

Background

The occurrence and clinical significance of asymptomatic bone stress injuries is unknown.

Hypothesis

To evaluate by clinical and magnetic resonance imaging follow-up the occurrence of asymptomatic bone stress injuries, their clinical significance, and whether they all progress to stress fractures in subjects undergoing intensive physical training.

Study Design

Cohort study (prognosis); Level of evidence, 1.

Methods

Twenty-one male elite-unit military recruits voluntarily underwent clinical examination and magnetic resonance imaging before their intensive training period, 6 weeks into it, and on completion of the 5-month training program.

Results

Based on magnetic resonance imaging, a total of 75 bone stress injuries were detected. Only 40% (30/75) of the bone stress injuries had been symptomatic. Symptoms depended on location and magnetic resonance imaging grade of injury, with higher grades usually more symptomatic. Repeated clinical and magnetic resonance imaging assessment indicated that asymptomatic grade I bone stress injuries healed (21/25, 84%) or remained grade I and asymptomatic (3/25, 12%). The numbers of bone stress injuries, symptomatic cases, and recruits with bone stress injury increased toward the end of the intensive training period.

Conclusions

Asymptomatic grade I bone stress injuries seem common in subjects undergoing intensive physical training. Such bone stress injuries heal or remain asymptomatic grade I bone stress injuries even if intensive physical activity continues. They are therefore of no clinical significance. Only subjects who exhibit symptoms need undergo imaging studies. Subjects with an asymptomatic grade I bone stress injury may continue training but should be clinically monitored for symptoms.
Primary Anterior Cruciate Ligament Reconstruction Using Fresh-Frozen, Nonirradiated Patellar Tendon Allograft
Authors: Bach Bernard R. , Aadalen Kirk J. , Dennis Michael G. , Carreira Dominic S. , Bojchuk John , Hayden Jennifer K. , Bush-Joseph Charles A.
Published: December 2004

Background

There are conflicting reports of allograft performance, immune response, tissue incorporation, and rerupture rates when used for anterior cruciate ligament reconstruction.

Purpose

To evaluate the clinical outcome of a fresh-frozen, nonirradiated, patellar tendon allograft for primary anterior cruciate ligament reconstruction surgery.

Study Design

Case series; Level of evidence, 4.

Methods

Patients who underwent endoscopic primary anterior cruciate ligament reconstruction with allograft tissue a minimum of 2 years ago were evaluated with physical examinations, the KT-1000 arthrometer, functional testing, radiographic evaluation, subjective assessment, and outcomes tools.

Results

Fifty-nine patients (60 knees) were evaluated at an average of 51 months after surgery. Ninety-four percent of patients were mostly or completely satisfied. A negative pivot shift test result was noted in 90% of subjects. The KT-1000 arthrometer side-to-side differences were = 3 mm in 95% of patients, and no patient exceeded 5 mm. The mean International Knee Documentation Committee score was 78 (SD = 19), and the mean Lysholm score was 82 (SD = 17). There were no clinical symptoms consistent with graft rejection or infection. Radiographic evaluation demonstrated infrequent significant tunnel widening.

Conclusions

Use of a fresh-frozen, nonirradiated allograft for primary reconstruction of the anterior cruciate ligament is a successful procedure both subjectively and functionally for restoring stability in patients selected for allograft reconstruction. In the patients selected for this surgical procedure, clinical, arthrometric stability testing, and subjective satisfaction were comparable to our previously published cohort studies using patellar tendon autograft at similar postoperative follow-up.
Effect of Cyclic Loading on New Polyblend Suture Coupled with Different Anchors
Authors: De Carli Angelo , Vadalà Antonio , Monaco Edoardo , Labianca Luca , Zanzotto Edoardo , Ferretti Andrea
Published: December 2004

Background

Secure tendon-to-bone fixation is essential for successful rotator cuff repair. Biomechanical properties of devices used in rotator cuff repair should be better understood.

Purpose

To evaluate the response to incremental cyclic loading of 6 different anchor-suture complexes commonly used in rotator cuff repair.

Study Design

Controlled laboratory study.

Methods

Two absorbable anchors 5 mm and 6.5 mm in diameter and 1 metallic anchor, coupled with Ethibond or FiberWire, were tested on 5 pairs of fresh-frozen human cadaveric shoulders. An incremental cyclic load was applied until failure using a Zwich-Roell Z010 electromechanical testing machine. The ultimate failure load and mode of failure were recorded. An analysis of variance model was used for statistical analysis.

Results

The FiberWire suture coupled with both absorbable and metallic anchors provided statistically significantly stronger fixation. However, although the metallic anchors in most cases failed because of slippage of the anchor, absorbable anchors failed because of rupture of the eyelet.

Conclusions

The FiberWire seems to increase the strength of fixation devices under cyclic load using both absorbable and metallic anchors, with relevant differences in failure mode (slippage of the metallic anchor and eyelet failure in the absorbable anchor).

Clinical Relevance

Use of the FiberWire suture might change the mode of failure of the suture-anchor complexes.
American Collegiate Men's Ice Hockey
Authors: Flik Kyle , Lyman Stephen , Marx Robert G.
Published: December 2004

Background

Reported rates and types of ice hockey injuries have been variable. Ice hockey combines tremendous speeds with aggressive physical play and therefore has great inherent potential for injury.

Purpose

To identify rates and determinants of injury in American men's collegiate ice hockey.

Study Design

Prospective cohort study.

Methods

Data were collected from 8 teams in a Division I athletic conference for 1 season using an injury reporting form specific for ice hockey.

Results

There were a total of 113 injuries in 23 096 athlete exposures. Sixty-five percent of injuries occurred during games, although games accounted for only 23% of all exposures. The overall injury rate was 4.9 per 1000 athlete exposures (13.8 per 1000 game athlete exposures and 2.2 per 1000 practice athlete exposures). Collision with an opponent (32.8%) or the boards (18.6%) caused more than half of all injuries. Concussion (18.6%) was the most common injury, followed by knee medial collateral ligament sprains, acromioclavicular joint injuries, and ankle sprains.

Conclusions

The risk of injury in men's collegiate ice hockey is much greater during games than during practices. Concussions are a main cause for time lost and remain an area of major concern.
The Effect of Anterior Cruciate Ligament Reconstruction on Knee Joint Kinematics under Simulated Muscle Loads
Authors: Yoo Jae Doo , Papannagari Ramprasad , Park Sang Eun , DeFrate Louis E. , Gill Thomas J. , Li Guoan
Published: December 2004

Background

Numerous studies have investigated anterior stability of the knee during the anterior drawer test after anterior cruciate ligament reconstruction. Few studies have evaluated anterior cruciate ligament reconstruction under physiological loads.

Purpose

To determine whether anterior cruciate ligament reconstruction reproduced knee motion under simulated muscle loads.

Study Design

Controlled laboratory study.

Methods

Eight human cadaveric knees were tested with the anterior cruciate ligament intact, transected, and reconstructed (using a bone–patellar tendon–bone graft) on a robotic testing system. Tibial translation and rotation were measured at 0 °, 15 °, 30 °, 60 °, and 90 ° of flexion under anterior drawer loading (130 N), quadriceps muscle loading (400 N), and combined quadriceps and hamstring muscle loading (400 N and 200 N, respectively). Repeated-measures analysis of variance and the Student-Newman-Keuls test were used to detect statistically significant differences between knee states.

Results

Anterior cruciate ligament reconstruction resulted in a clinically satisfactory anterior tibial translation. The anterior tibial translation of the reconstructed knee was 1.93 mm larger than the intact knee at 30 ° of flexion under anterior load. Anterior cruciate ligament reconstruction overconstrained tibial rotation, causing significantly less internal tibial rotation in the reconstructed knee at low flexion angles (0 °-30 °) under muscle loads (P<. 05). At 30 ° of flexion, under muscle loads, the tibia of the reconstructed knee was 1.9 ° externally rotated compared to the intact knee.

Conclusions

Anterior cruciate ligament reconstruction may not restore the rotational kinematics of the intact knee under muscle loads, even though anterior tibial translation was restored to a clinically satisfactory level under anterior drawer loads. These data suggest that reproducing anterior stability under anterior tibial loads may not ensure that knee joint kinematics is restored under physiological loading conditions.

Clinical Relevance

Decreased internal rotation of the knee after anterior cruciate ligament reconstruction may lead to increased patellofemoral joint contact pressures. Future anterior cruciate ligament reconstruction techniques should aim at restoring 3-dimensional knee kinematics under physiological loads.
Bleaching-induced Colour Change in Plastic Filling Materials
Authors: Yalcin Filiz , Gurgan Sevil
Published: December 2004

The purpose of this in vitro study is to compare the colour changes of five different tooth-coloured restoratives: Ormocer (Definite/Degussa), compomer (Dyract AP/Dentsply De Tray), packable composite (Filtek P60/3M), flowable composite (Filtek Flow/3M) and hybrid composite (Filtek Z250/3M) after two different bleaching regimens [Vivastyle (10% carbamide peroxide)/Vivadent and Crest Professional Whitestrips (6.5% hydrogen peroxide strip bands)/Procter & Gamble]. Fifteen specimens of 30 × 30 × 2mm3 size were fabricated from each material and randomly divided into three groups of five. Specimens in group one were stored in distilled water at 37°C for two weeks and served as control. Group two specimens were treated with Vivastyle for two hours per day for two weeks and group three specimens were treated with Whitestrips for 30 min twice daily for two weeks. During the test period the specimens were kept at 37 C and in 100% relative humidity. At the end of the bleaching regimens colour measurements of the control and test groups were made with UV visible recording spectrophotometer. Colour changes were calculated with the use of the CIE-LAB uniform colour scale and compared by the use of Kruskall–Wallis test, followed by the Mann–Whitney U test. Control, Vivastyle and Whitestrips L*, a* and b* values differed significantly for all materials except Filtek Z250 ( p < 0.05). All restorative materials demonstrated significantly higher colour change (Δ E) with Whitestrips ( p < 0.05). Dyract AP demonstrated the highest colour change both for the bleaching regimens followed by Filtek Flow, Definite, Filtek P60, and Filtek Z250 showed the smallest colour change. Colour change of plastic restorative materials during bleaching is both filling material and bleach specific.
Hydraulic Permeability of Polyglycolic Acid Scaffolds as a Function of Biomaterial Degradation
Authors: Li Jiashen , Mak Arthur F. T.
Published: December 2004

Using a simple experimental setup, the hydraulic permeability of fibrous nonwoven polyglycolic acid (PGA) scaffolds is studied after different degradation durations in PBS. The hydraulic permeability of the scaffolds increased with the degradation time. After being incubated for about 4 weeks, the permeability of the scaffold begins to drop. It is noted that the PGA scaffold apparently begins to contract and cannot maintain its original shape after 4 weeks of degradation. These results underpin the understanding of the biotransport processes in the scaffolds during tissue engineering experiments.
Mineral dust in urban air: Beijing, China
Authors: Whittaker A. G. , Jones T. P. , Shao L. , Shi Z. , Bérubé K. A. , Richards R. J.
Published: December 2004

The PM10 (airborne particulate matter with aerodynamic diameter <10 mm) in Beijing has a distinct seasonality, with industrial, domestic and natural sources providing a heterogeneous cocktail of airborne particulate matter (PM). Collections were made during late winter, summer and high wind dust storms to determine composition and probable sources of this PM. The concentration of the PM during winter (174 μg m–3) was approximately four times higher than summer (37 μg m–3) with dust storms raising the concentration further (200 μg m–3). During the winter the PM was dominated by combustion products (66% filter area). During the summer combustion products and loess contributed ~35% to the filter area each, but during elevated wind speeds (>10 mph) loess completely dominated the collections (96% filter area). The majority of the PM10 collected was in the respirable (PM2.5) size range (winter 99.7%, summer 96.6%, dust storms 82.3%). The loess in Beijing comprises quartz, feldspar, calcite, chlorite and mica and is in the coarse silt to sand (20–60 mm) size range. The collections are therefore likely to be made up of finer silt and clay, primarily derived from of the erosion of cultivated land. Using a plasmid assay, the Beijing particulate matter was found to have little or no surface free radical activity.
Haptoglobin modifies the hemochromatosis phenotype in mice
Authors: Tolosano Emanuela , Fagoonee Sharmila , Garuti Cinzia , Valli Linda , Andrews Nancy C. , Altruda Fiorella , Pietrangelo Antonello
Published: December 2004

Classic hereditary hemochromatosis (HH) is a common genetic disorder of iron metabolism caused by a mutation in the HFE gene. Whereas the prevalence of the mutation is very high, the clinical penetrance of the disease is low, suggesting that the HFE mutation is a necessary but not sufficient cause of clinical HH. Several candidate modifier genes have been proposed in mice and humans, including haptoglobin. Haptoglobin is the plasma protein with the highest binding affinity for hemoglobin. It delivers free plasma hemoglobin to the reticuloendothelial system, thus reducing loss of hemoglobin through the glomeruli and allowing heme-iron recycling. To gain insight into the role of haptoglobin as a modifier gene in HH, we used Hfe and haptoglobin double-null mice. Here, we show that Hfe and haptoglobin compound mutant mice accumulate significantly less hepatic iron than Hfe-null mice, thus demonstrating that haptoglobin-mediated heme-iron recovery may contribute significantly to iron loading in HH. (Blood. 2005;105:3353-3355)