bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arterial viscoelasticity: role in the dependency of pulse wave velocity on heart rate in conduit arteries
Authors: Xiao Hanguang , Tan Isabella , Butlin Mark , Li Decai , Avolio Alberto P. 
Published: March 2017

Experimental investigations have established that the stiffness of large arteries has a dependency on acute heart rate (HR) changes. However, the possible underlying mechanisms inherent in this HR dependency have not been well established. This study aimed to explore a plausible viscoelastic mechanism by which HR exerts an influence on arterial stiffness. A multisegment transmission line model of the human arterial tree incorporating fractional viscoelastic components in each segment was used to investigate the effect of varying fractional order parameter (α) of viscoelasticity on the dependence of aortic arch to femoral artery pulse wave velocity (afPWV) on HR. HR was varied from 60 to 100 beats/min at a fixed mean flow of 100 ml/s. PWV was calculated by intersecting tangent method (afPWVTan) and by phase velocity from the transfer function (afPWVTF) in the time and frequency domain, respectively. PWV was significantly and positively associated with HR for α ≥ 0.6; for α = 0.6, 0.8, and 1, HR-dependent changes in afPWVTan were 0.01 ± 0.02, 0.07 ± 0.04, and 0.22 ± 0.09 m/s per 5 beats/min; HR-dependent changes in afPWVTF were 0.02 ± 0.01, 0.12 ± 0.00, and 0.34 ± 0.01 m/s per 5 beats/min, respectively. This crosses the range of previous physiological studies where the dependence of PWV on HR was found to be between 0.08 and 0.10 m/s per 5 beats/min. Therefore, viscoelasticity of the arterial wall could contribute to mechanisms through which large artery stiffness changes with changing HR. Physiological studies are required to confirm this mechanism. NEW & NOTEWORTHY This study used a transmission line model to elucidate the role of arterial viscoelasticity in the dependency of pulse wave velocity on heart rate. The model uses fractional viscoelasticity concepts, which provided novel insights into arterial hemodynamics. This study also provides a means of assessing the clinical manifestation of the association of pulse wave velocity and heart rate.
Prosthetic model, but not stiffness or height, affects the metabolic cost of running for athletes with unilateral transtibial amputations
Authors: Beck Owen N. , Taboga Paolo , Grabowski Alena M. 
Published: March 2017

Running-specific prostheses enable athletes with lower limb amputations to run by emulating the spring-like function of biological legs. Current prosthetic stiffness and height recommendations aim to mitigate kinematic asymmetries for athletes with unilateral transtibial amputations. However, it is unclear how different prosthetic configurations influence the biomechanics and metabolic cost of running. Consequently, we investigated how prosthetic model, stiffness, and height affect the biomechanics and metabolic cost of running. Ten athletes with unilateral transtibial amputations each performed 15 running trials at 2.5 or 3.0 m/s while we measured ground reaction forces and metabolic rates. Athletes ran using three different prosthetic models with five different stiffness category and height combinations per model. Use of an Ottobock 1E90 Sprinter prosthesis reduced metabolic cost by 4.3 and 3.4% compared with use of Freedom Innovations Catapult [fixed effect (β) = −0.177; P < 0.001] and Össur Flex-Run (β = −0.139; P = 0.002) prostheses, respectively. Neither prosthetic stiffness ( P ≥ 0.180) nor height ( P = 0.062) affected the metabolic cost of running. The metabolic cost of running was related to lower peak (β = 0.649; P = 0.001) and stance average (β = 0.772; P = 0.018) vertical ground reaction forces, prolonged ground contact times (β = −4.349; P = 0.012), and decreased leg stiffness (β = 0.071; P < 0.001) averaged from both legs. Metabolic cost was reduced with more symmetric peak vertical ground reaction forces (β = 0.007; P = 0.003) but was unrelated to stride kinematic symmetry ( P ≥ 0.636). Therefore, prosthetic recommendations based on symmetric stride kinematics do not necessarily minimize the metabolic cost of running. Instead, an optimal prosthetic model, which improves overall biomechanics, minimizes the metabolic cost of running for athletes with unilateral transtibial amputations.NEW & NOTEWORTHY The metabolic cost of running for athletes with unilateral transtibial amputations depends on prosthetic model and is associated with lower peak and stance average vertical ground reaction forces, longer contact times, and reduced leg stiffness. Metabolic cost is unrelated to prosthetic stiffness, height, and stride kinematic symmetry. Unlike nonamputees who decrease leg stiffness with increased in-series surface stiffness, biological limb stiffness for athletes with unilateral transtibial amputations is positively correlated with increased in-series (prosthetic) stiffness.
Mathematical Modeling Links Pregnancy-Associated Changes and Breast Cancer Risk
Authors: Temko Daniel , Cheng Yu-Kang , Polyak Kornelia , Michor Franziska 
Published: March 2017

Abstract
Recent debate has concentrated on the contribution of bad luck to cancer development. The tight correlation between the number of tissue-specific stem cell divisions and cancer risk of the same tissue suggests that bad luck has an important role to play in tumor development, but the full extent of this contribution remains an open question. Improved understanding of the interplay between extrinsic and intrinsic factors at the molecular level is one promising route to identifying the limits on extrinsic control of tumor initiation, which is highly relevant to cancer prevention. Here, we use a simple mathematical model to show that recent data on the variation in numbers of breast epithelial cells with progenitor features due to pregnancy are sufficient to explain the known protective effect of full-term pregnancy in early adulthood for estrogen receptor–positive (ER+) breast cancer later in life. Our work provides a mechanism for this previously ill-understood effect and illuminates the complex influence of extrinsic factors at the molecular level in breast cancer. These findings represent an important contribution to the ongoing research into the role of bad luck in human tumorigenesis. Cancer Res; 77(11); 2800–9. ©2017 AACR.
Influence of Left Atrial Function on Exercise Capacity and Left Ventricular Function in Patients With Heart Failure and Preserved Ejection Fraction
Authors: von Roeder Maximilian , Rommel Karl-Philipp , Kowallick Johannes Tammo , Blazek Stephan , Besler Christian , Fengler Karl , Lotz Joachim , Hasenfuß Gerd , Lücke Christian , Gutberlet Matthias , Schuler Gerhard , Schuster Andreas , Lurz Philipp 
Published: March 2017

Background—
Although left atrial (LA) dysfunction is common in heart failure with preserved ejection fraction (HFpEF), its functional implications beyond the reflection of left ventricular (LV) pathology are not well understood. The aim of this study was to further characterize LA function in HFpEF patients.

Methods and Results—

We performed cardiac magnetic resonance myocardial feature tracking in 22 patients with HFpEF and 12 patients without HFpEF. LA reservoir strain, LA conduit strain, and LA booster pump strain were quantified. Peak oxygen uptake (VO2max) was determined. Invasive pressure–volume loops were obtained to evaluate LV diastolic properties. LV early filling was determined from LV volume–time curves as derived from cardiac magnetic resonance. LA reservoir and conduit strain were significantly lower in HFpEF (LA reservoir strain, 22±7% versus 29±6%,
P
=0.04; LA conduit strain, −9±5% versus −15±4%,
P
<0.01). Patients with HFpEF showed lower oxygen uptake (17±6 versus 29±8 mL/(kg min);
P
<0.01). Strain measurement for LA conduit function was strongly associated with VO2max (
r
=0.80;
P
<0.01). On multivariable regression analysis, LA conduit strain emerged as strongest predictor for VO2max even after inclusion of LV stiffness and relaxation time (β=0.80;
P
<0.01). LA conduit strain correlated with the volume of early ventricular filling (
r
=0.67;
P
<0.01), but not LV stiffness constant β (−0.34;
P
=0.051) or relaxation constant τ (
r
=−0.33;
P
=0.06).

Conclusions—
Cardiac magnetic resonance myocardial feature tracking–derived conduit strain is significantly impaired in HFpEF and associated with exercise intolerance. Impaired conduit function is associated with impaired early ventricular filling, as potential mechanism leading to impaired oxygen uptake. Our results propose that impaired LA conduit function represents a distinct feature of HFpEF, independent of LV stiffness and relaxation.

Clinical Trial Registration—

URL:
http://www.clinicaltrials.gov
. Unique identifier: NCT02459626.
Multimodality Strategy for Cardiovascular Risk Assessment
Authors: de Lemos James A. , Ayers Colby R. , Levine Benjamin D. , deFilippi Christopher R. , Wang Thomas J. , Hundley W. Gregory , Berry Jarett D. , Seliger Stephen L. , McGuire Darren K. , Ouyang Pamela , Drazner Mark H. , Budoff Matthew , Greenland Philip , Ballantyne Christie M. , Khera Amit 
Published: March 2017

Background:
Current strategies for cardiovascular disease (CVD) risk assessment among adults without known CVD are limited by suboptimal performance and a narrow focus on only atherosclerotic CVD (ASCVD). We hypothesized that a strategy combining promising biomarkers across multiple different testing modalities would improve global and atherosclerotic CVD risk assessment among individuals without known CVD.

Methods:
We included participants from MESA (Multi-Ethnic Study of Atherosclerosis) (n=6621) and the Dallas Heart Study (n=2202) who were free from CVD and underwent measurement of left ventricular hypertrophy by ECG, coronary artery calcium, N-terminal pro B-type natriuretic peptide, high-sensitivity cardiac troponin T, and high-sensitivity C-reactive protein. Associations of test results with the global composite CVD outcome (CVD death, myocardial infarction, stroke, coronary or peripheral revascularization, incident heart failure, or atrial fibrillation) and ASCVD (fatal or nonfatal myocardial infarction or stroke) were assessed over >10 years of follow-up. Multivariable analyses for the primary global CVD end point adjusted for traditional risk factors plus statin use and creatinine (base model).

Results:

Each test result was independently associated with global composite CVD events in MESA after adjustment for the components of the base model and the other test results (
P
<0.05 for each). When the 5 tests were added to the base model, the c-statistic improved from 0.74 to 0.79 (
P
=0.001), significant integrated discrimination improvement (0.07, 95% confidence interval [CI] 0.06–0.08,
P
<0.001) and category free net reclassification improvement (0.47; 95% CI, 0.38–0.56;
P
=0.003) were observed, and the model was well calibrated (χ
2
=12.2,
P
=0.20). Using a simple integer score counting the number of abnormal tests, compared with those with a score of 0, global CVD risk was increased among participants with a score of 1 (adjusted hazard ratio, 1.9; 95% CI, 1.4–2.6), 2 (hazard ratio, 3.2; 95% CI, 2.3–4.4), 3 (hazard ratio, 4.7; 95% CI, 3.4–6.5), and ≥4 (hazard ratio, 7.5; 95% CI, 5.2–10.6). Findings replicated in the Dallas Health Study were similar for the ASCVD outcome.

Conclusions:
Among adults without known CVD, a novel multimodality testing strategy using left ventricular hypertrophy by ECG, coronary artery calcium, N-terminal pro B-type natriuretic peptide, high-sensitivity cardiac troponin T, and high-sensitivity C-reactive protein significantly improved global CVD and ASCVD risk assessment.
Biomarker Profiles in Heart Failure Patients With Preserved and Reduced Ejection Fraction
Authors: Tromp Jasper , Khan Mohsin A. F. , Klip IJsbrand T. , Meyer Sven , de Boer Rudolf A. , Jaarsma Tiny , Hillege Hans , van Veldhuisen Dirk J. , van der Meer Peter , Voors Adriaan A. 
Published: March 2017

Background

Biomarkers may help us to unravel differences in the underlying pathophysiology between heart failure (
HF
) patients with a reduced ejection fraction (
HF
r
EF
) and a preserved ejection fraction (
HF
p
EF
). Therefore, we compared biomarker profiles to characterize pathophysiological differences between patients with
HF
r
EF
and
HF
p
EF
.

Methods and Results

We retrospectively analyzed 33 biomarkers from different pathophysiological domains (inflammation, oxidative stress, remodeling, cardiac stretch, angiogenesis, arteriosclerosis, and renal function) in 460
HF
patients (21%
HF
p
EF
, left ventricular ejection fraction ≥45%) measured at discharge after hospitalization for acute
HF
. The association between these markers and the occurrence of all‐cause mortality and/or
HF
‐related rehospitalizations at 18 months was compared between patients with
HF
r
EF
and
HF
p
EF
. Patients were 70.6±11.4 years old and 37.4% were female. Patients with
HF
p
EF
were older, more often female, and had a higher systolic blood pressure. Levels of high‐sensitive C‐reactive protein were significantly higher in
HF
p
EF
, while levels of pro‐atrial‐type natriuretic peptide and N‐terminal pro‐brain natriuretic peptide were higher in
HF
r
EF
. Linear regression followed by network analyses revealed prominent inflammation and angiogenesis‐associated interactions in
HF
p
EF
and mainly cardiac stretch–associated interactions in
HF
r
EF
. The angiogenesis‐specific marker, neuropilin and the remodeling‐specific marker, osteopontin were predictive for all‐cause mortality and/or
HF
‐related rehospitalizations at 18 months in
HF
p
EF
, but not in
HF
r
EF
(
P
for interaction <0.05).

Conclusions

In
HF
p
EF
, inflammation and angiogenesis‐mediated interactions are predominantly observed, while stretch‐mediated interactions are found in
HF
r
EF
. The remodeling marker osteopontin and the angiogenesis marker neuropilin predicted outcome in
HF
p
EF
, but not in
HF
r
EF
.
Progressive massive fibrosis in patients with pneumoconiosis: utility of MRI in differentiating from lung cancer
Authors: Ogihara Yukihiro , Ashizawa Kazuto , Hayashi Hideyuki , Nagayasu Takeshi , Hayashi Tomayoshi , Honda Sumihisa , Uetani Masataka 
Published: March 2017

Background It is occasionally difficult to distinguish progressive massive fibrosis (PMF) from lung cancer on computed tomography (CT) in patients with pneumoconiosis. Purpose To evaluate the magnetic resonance imaging (MRI) features of PMF and to assess its ability to differentiate PMF from lung cancer. Material and Methods Between 2000 and 2014, 40 pulmonary lesions suspected to be lung cancer on the basis of CT in 28 patients with known pneumoconiosis were evaluated. Twenty-four of the 40 lesions were pathologically or clinically diagnosed as PMF. The signal pattern on T2-weighted (T2W) images, post-contrast enhancement pattern on T1-weighted (T1W) images, and the pattern of the time intensity curve (TIC) on contrast-enhanced dynamic studies were evaluated. All images were analyzed independently by two chest radiologists. Results All 24 PMF lesions showed low signal intensity (SI) on T2W images (sensitivity, 100%), while 15 of 16 lung cancer lesions showed intermediate or high SI on T2W images (specificity, 94%) when PMF was regarded as a positive result. Six of 17 PMF lesions showed a homogeneous enhancement pattern (sensitivity, 35%), and 4/9 lung cancer lesions showed an inhomogeneous or a ring-like enhancement pattern (specificity, 44%). Six of 16 PMF lesions showed a gradually increasing enhancement pattern (sensitivity, 38%), and 7/9 lung cancer lesions showed rapid enhancement pattern (specificity, 78%). Conclusion When differentiation between PMF and lung cancer in patients with pneumoconiosis is difficult on CT, an additional MRI study, particularly the T2W imaging sequence, may help differentiate between the two.
Salvage of Combat Hindfoot Fractures in 2003-2014 UK Military
Authors: Bennett Philippa M. , Stevenson Thomas , Sargeant Ian D. , Mountain Alistair , Penn-Barwell Jowan G. 
Published: March 2017

Background: Hindfoot fractures pose a considerable challenge to military orthopaedic surgeons, as combat injuries are typically the result of energy transfers not seen in civilian practice. This study aimed to characterize the pattern of hindfoot injuries sustained by UK military casualties in recent conflicts, define the early amputation and infection rate, and identify factors associated with poor early outcomes. Methods: The UK Joint Theatre Trauma Registry was searched for British military casualties sustaining a hindfoot fracture from Iraq and Afghanistan between 2003 and 2014. Data on the injury pattern and management were obtained along with 18-month follow-up data. Statistical analysis was performed with the chi-square test and binomial logistic regression analysis. The threshold for significance was set at P < .05. One hundred fourteen patients sustained 134 hindfoot injuries. Eighteen-month follow-up was available for 92 patients (81%) and 114 hindfeet (85%). Results: The calcaneus was fractured in 116 cases (87%): 54 (47%) were managed conservatively, 32 (28%) underwent K-wire fixation, and 30 (26%) underwent internal fixation. Nineteen patients (17%) required transtibial amputation during this time. A deep infection requiring operative treatment occurred in 13 cases (11%) with Staphylococcus aureus, the most common infectious organism (46%). A deep infection was strongly associated with operative fracture management ( P = .0016). When controlling for multiple variables, the presence of a deep infection was significantly associated with a requirement for amputation at 18 months ( P = .023). There was no association between open fractures and a requirement for amputation at 18 months ( P = .640), nor was conservative management associated with a requirement for amputation ( P = .999). Thirty-six fractures (32%) required unplanned revision surgery within the first 18 months following salvage, of which 19 (53%) involved amputation. Conclusion: A deep infection was the sole variable significantly associated with a requirement for amputation by 18 months. These results suggest that attempts at salvaging these injuries are at the limits of orthopaedic technical feasibility. Level of Evidence: Level III, comparative series.
Heterogeneous impact of body mass index on in-hospital mortality in acute heart failure syndromes: An analysis from the ATTEND Registry
Authors: Yoshihisa Akiomi , Sato Takamasa , Kajimoto Katsuya , Sato Naoki , Takeishi Yasuchika ,   on behalf of the Acute Decompensated Heart Failure Syndromes (ATTEND) investigators
Published: March 2017

Background:Although the obesity paradox may vary depending upon clinical background factors such as age, gender, aetiology of heart failure and comorbidities, the reasons underlying the heterogeneous impact of body mass index (BMI) on in-hospital cardiac mortality under various conditions in patients with acute heart failure syndromes (AHFSs) remain unclear.Methods:Among 4617 hospitalised patients with AHFSs enrolled in the Acute Decompensated Heart Failure Syndromes (ATTEND) registry, the patient characteristics and in-hospital cardiac mortality rates in those with low BMI (BMI <25 kg/m2, n = 3263) were compared to those with high BMI (BMI ⩾25 kg/m2, n = 1354).Results:Compared to the high-BMI group, the low-BMI group was significantly older, less likely to be male and to have hypertensive or idiopathic dilated aetiologies and more likely to have valvular aetiologies and a history of prior hospitalisation for AHFS. The low-BMI group also had lower prevalence rates of diabetes, dyslipidaemia, hypertension and atrial fibrillation and higher prevalence rates of anaemia and chronic obstructive pulmonary disease. In addition, cardiac mortality was significantly higher in the low-BMI group than in the high-BMI group (5.5 vs. 1.5%, p < 0.001). Logistic regression analysis demonstrated that low BMI was a predictor of cardiac mortality (odds ratio: 3.89, 95% confidence interval: 2.44–6.21). In subgroup analyses, the impact of BMI on cardiac mortality differed depending on the presence of hypertensive aetiology, hypertension, chronic obstructive pulmonary disease and hyponatremia (all p < 0.05), although there were no interactions between the impacts of BMI and age, gender, other aetiologies, prior hospitalisation, diabetes, anaemia, cardio-renal function and in-hospital management.Conclusion:It is necessary to appreciate the obesity paradox in AHFS patients, and a patient’s heterogeneous background should also be considered.
The Functional Arm Scale for Throwers (FAST)—Part I: The Design and Development of an Upper Extremity Region-Specific and Population-Specific Patient-Reported Outcome Scale for Throwing Athletes
Authors: Sauers Eric L. , Bay R. Curtis , Snyder Valier Alison R. , Ellery Traci , Huxel Bliven Kellie C. 
Published: March 2017

Background: Upper extremity (UE) region-specific, patient-reported outcome (PRO) scales assess injuries to the UE but do not account for the demands of overhead throwing athletes or measure patient-oriented domains of health-related quality of life (HRQOL). Purpose: To develop the Functional Arm Scale for Throwers (FAST), a UE region-specific and population-specific PRO scale that assesses multiple domains of disablement in throwing athletes with UE injuries. In stage I, a beta version of the scale was developed for subsequent factor identification, final item reduction, and construct validity analysis during stage II. Study Design: Descriptive laboratory study. Methods: Three-stage scale development was utilized: Stage I (item generation and initial item reduction) and stage II (factor analysis, final item reduction, and construct validity) are reported herein, and stage III (establishment of measurement properties [reliability and validity]) will be reported in a companion paper. In stage I, a beta version was developed, incorporating National Center for Medical Rehabilitation Research disablement domains and ensuring a blend of sport-related and non–sport-related items. An expert panel and focus group assessed importance and interpretability of each item. During stage II, the FAST was reduced, preserving variance characteristics and factor structure of the beta version and construct validity of the final FAST scale. Results: During stage I, a 54-item beta version and a separate 9-item pitcher module were developed. During stage II, a 22-item FAST and 9-item pitcher module were finalized. The factor solution for FAST scale items included pain (n = 6), throwing (n = 10), activities of daily living (n = 5), psychological impact (n = 4), and advancement (n = 3). The 6-item pain subscale crossed factors. The remaining subscales and pitcher module are distinctive, correlated, and internally consistent and may be interpreted individually or combined. Conclusion: This article describes the development of the FAST, which assesses clinical outcomes and HRQOL of throwing athletes after UE injury. The FAST encompasses multiple domains of disability and demonstrates excellent construct validity. Clinical Relevance: The FAST provides a single UE region-specific and population-specific PRO scale for high-demand throwers to facilitate measurement of impact of UE injuries on HRQOL and clinical outcomes while quantifying recovery for comparative effectiveness studies.