654 research outputs found
SDF1 Gene Variation Is Associated with Circulating SDF1 alpha Level and Endothelial Progenitor Cell Number-The Bruneck Study
BACKGROUND: Stromal cell-derived factor-1 (SDF1) and its receptor CXC chemokine receptor 4 (CXCR4) play a critical role in progenitor cell homing, mobilization and differentiation. It would be interesting to assess the predictive value of SDF-1alpha level for EPC number, and to ascertain whether there is a relationship between SDF1 gene variation, plasma SDF-1alpha level, and the number and function of circulating EPCs. We also tested whether EPC number and function was related to CXCR4 gene variation.
METHODOLOGY AND PRINCIPAL FINDINGS: We genotyped a cohort of individuals who participated in the Bruneck Study for single nucleotide polymorphisms (SNPs) in the SDF1 and CXCR4 genes, and measured blood SDF1alpha level as well as EPC number and function. SDF1alpha levels were correlated with age, gender, alcohol consumption, circulating reticulocyte numbers, and concentrations of matrix metalloproteinase-9, C-reactive protein, cystatin C, fibrinogen and homocytein. In blood samples taken in 2005, EPC number was inversely associated with SDF1alpha level (p<0.001). EPC number in 2005 was also inversely associated with SDF1alpha level in 2000 (p = 0.009), suggesting a predictive value of plasma SDF1alpha level for EPC number. There was an association between the SDF1 gene rs2297630 SNP A/A genotype, increased SDF1alpha level (p = 0.002) and lower EPC number (p = 0.006).
CONCLUSIONS: Our data indicate that a SDF1 gene variation (rs2297630) has an influence on SDF1alpha level and circulating EPC number, and that plasma SDF1alpha level is a predictor of EPC number
Novel Approach to Repairing a Traumatic Aortic Arch Pseudoaneurysm Following a Fall.
Traumatic pseudoaneurysms of the aortic arch are often treated with surgical repair regardless of the lesion size or age. The authors report a simple, less invasive surgical repair in a patient who sustained blunt aortic injury following a fall
Effect of Anionic Polymers on Drug Loading and Release from Clindamycin Phosphate Solid Lipid Nanoparticles
Purpose: To develop and characterize solid lipid nanoparticle (SLN) systems containing dextran sulfate or sodium alginate as anionic polymers for the delivery of clindamycin phosphate as a model hydrophilic cationic drug.Methods: A multi-level factorial design was used for the preparation and optimization of clindamycin SLNs. Polymers (dextran sulfate and sodium alginate), Tween 80, and Pluronic F68 were chosen as the independent variables. The SLNs were prepared using stearic acid as the lipid matrix by an emulsion congealing technique with cold homogenization. Particle size and drug loading were evaluated as the primary responses. The morphology and drug release rate of the selected formulations were also determined.Results: The results revealed that incorporation of anionic polymers increased drug loading of theSLNs. Dextran sulfate had a greater effect on drug loading, increasing it from 1.32 to 18.19 %, compared to the 6.73 % achieved using sodium alginate. Dextran sulfate also reduced drug release rate by half compared with sodium alginate, probably due to the higher charge density, lower molecular weight and lower branching density of the ionic polymer.Conclusion: Incorporation of anionic polymers can increase the loading of clindamycin phosphate into SLNs. Drug release from SLNs is also dependent on the polymer type.Keywords: Clindamycin, Solid lipid nanoparticles, Dextran sulfate, Sodium alginate, Anionic polymers, Drug release, Drug loadin
Incidence of Neonatal Birth Injuries and Related Factors in Kashan, Iran
Background: Birth injuries are defined as the impairment of neonatal body function due to adverse events that occur at birth and can be avoidable or inevitable. Despite exact prenatal care, birth trauma usually occurs, particularly in long and difficult labor or fetal malpresentations.
Objectives: This study aimed to investigate the incidence of birth injuries and their related factors in Kashan, Iran, during 2012-2013.
Patients and Methods: In this cross-sectional study, all live-born neonates in the hospitals of Kashan City were assessed prospectively by a checklist included demographic variables (maternal age, weight, and nationality), reproductive and labor variables (prenatal care, parity, gestational age, premature rupture of membrane (PROM), fetal heart rate (FHR) pattern, duration of PROM, induction of labor, fundal pressure, shoulder dystocia, fetal presentation, duration of second stage, type of delivery, and delivery attendance), and neonatal variables (sex, birth weight, height, head circumference, Apgar score, and neonatal trauma). Birth trauma was diagnosed based on pediatrician or resident examination and in some cases confirmed by paraclinic methods. Statistical analyses were performed by chi-square, student’s t-test, and multiple logistic regression analyses using SPSS version 17. P ≤ 0.05 was considered statistically significant.
Results: In this study, the incidence of birth trauma was 2.2%. Incidence of trauma was 3.6% in vaginal deliveries and 1.2% in cesarean sections (P < 0.0001). The most common trauma was cephalohematoma (57.2%) and then asphyxia (16.8%). In multiple logistic regression analyses, decreased fetal heart rate (FHR), fundal pressure, shoulder dystocia, vaginal delivery, male sex, neonatal weight, delivery by resident, induction of labor, and delivery in a teaching hospital were predictors of birth trauma.
Conclusions: Overall, incidence of birth trauma in Kashan City was lower in comparison with most studies. Considering existing risk factors, further monitoring on labor, and delivery management in teaching hospitals are recommended to prevent birth injuries. In addition, careful supervision on students and residents' training should be applied in teaching hospitals
Evaluation of hemostatic and coagulation factor abnormalities in patients undergoing the Fontan operation
AbstractObjective: Low-velocity and nonlaminar flow patterns in the Fontan circulation, as well as abnormal liver function in some patients, may partly account for the coagulation abnormalities seen. We examined (1) coagulation factor abnormalities before and after the Fontan procedure and (2) regional coagulation factor abnormalities in the Fontan circulation. Methods: Levels of factors V, VII, VIII, X, antithrombin III, prothrombin fragment F1+2, protein C, and protein S were measured in 2 groups of patients: In 14 patients undergoing the Fontan procedure, blood was analyzed before the operation and 5 days after the operation (group 1). The median age in this group was 3.2 years. In 10 patients who had undergone the Fontan procedure, cardiac catheterization was performed and samples were taken from the femoral vein, inferior vena cava, right atrium, and pulmonary artery (group 2). The median age in this group was 6.2 years and the median follow-up from the Fontan procedure was 4.1 years. Results: In group 1 a significant increase was noted postoperatively in the concentration of factor VIII (P < .001), factor X (P < .001), and prothrombin fraction F1+2 (P < .001). A significant decrease in the levels of antithrombin III (P < .001), protein C (P < .004), and protein S (P < .02) was also found. The increase in factors VIII and X persisted at 4 years' follow-up in group 2 patients. In group 2, no significant regional differences were observed between the coagulation factors measured at different sites. Conclusions: There is an increased tendency toward coagulation after the Fontan procedure. A prothrombotic state is supported by thrombin generation associated with reduced antithrombin III concentration. This increase in coagulation may contribute to the early and late risks of thromboembolism observed after the Fontan procedure. We did not find any regional differences in coagulation abnormalities in patients late after the Fontan procedure. Therefore, the mechanisms and causes of the coagulation abnormalities remain unclear. (J Thorac Cardiovasc Surg 2000;120:778-82
Optimal B-spline Mapping of Flow Imaging Data for Imposing Patient-specific Velocity Profiles in Computational Hemodynamics.
OBJECTIVE: We propose a novel method to map patient-specific blood velocity profiles obtained from imaging data such as 2D flow MRI or 3D colour Doppler ultrasound) to geometric vascular models suitable to perform CFD simulations of haemodynamics. We describe the implementation and utilisation of the method within an open-source computational hemodynamics simulation software (CRIMSON). METHODS: The proposed method establishes point-wise correspondences between the contour of a fixed geometric model and time-varying contours containing the velocity image data, from which a continuous, smooth and cyclic deformation field is calculated. Our methodology is validated using synthetic data, and demonstrated using two different in-vivo aortic velocity datasets: a healthy subject with normal tricuspid valve and a patient with bicuspid aortic valve. RESULTS: We compare our method with the state-of-the-art Schwarz-Christoffel method, in terms of preservation of velocities and execution time. Our method is as accurate as the Schwarz-Christoffel method, while being over 8 times faster. CONCLUSIONS: Our mapping method can accurately preserve either the flow rate or the velocity field through the surface, and can cope with inconsistencies in motion and contour shape. SIGNIFICANCE: The proposed method and its integration into the CRIMSON software enable a streamlined approach towards incorporating more patient-specific data in blood flow simulations
Operative planning in Thoracic Surgery: A pilot study comparing imaging techniques and 3D printing.
BACKGROUND: Careful preoperative planning in thoracic surgery is essential for positive outcomes especially in video assisted thoracic surgery (VATS) where palpation and 3-dimensional imaging is restricted. The objective of this study was to evaluate the ability of different imaging techniques such as Computerized Tomography (CT) scanning, maximal intensity projection (MIP) imaging, 3-dimensional (3D) reconstruction as well as 3D printing, to define the anatomy of the hilar structures prior to anatomical lung resection. METHODS: All patients undergoing elective lung resections by VATS for cancer under a single surgeon were identified over a three-month period. A single surgeon was asked to record the number of pulmonary artery branches supplying the lobe to be resected using the preoperative CT scan, MIP images and 3D reconstructed CT images. 3 patients had their lung hilum printed. These were then compared to the intraoperative findings. RESULTS: 16 patients had their preoperative imaging analyzed. A further 3 patients had their lung hilum 3D printed. Although not statistically significant, the 3D prints of the hilum were found to be the most accurate measurement with a correlation of 0.92. CT, 3D reconstructed CT and MIP images tended to under recognize the number of arterial branches and therefore scored between 0.26 and 0.39 in terms of absolute agreement with the number of arteries found at operation. CONCLUSIONS: 3D printing in the planning of thoracic surgery may suggest a benefit over contemporary available imaging modalities and the use of 3D printing in practicing operations is being established
Multiworm algorithm quantum Monte Carlo
We review the path-integral quantum Monte Carlo method and discuss its
implementation by multiworm algorithms. We analyze in details the features of
the algorithms, and focus our attention on the computation of the -body
density matrix to study N-body correlations. Finally, we demonstrate the
validity of the algorithms on a system of dipolar bosons trapped in a stack of
one-dimensional layers in the case of zero and finite inter-layer hopping.Comment: 20 pages, 10 figure
Output-only Modal Identification of beams with different boundary condition
Structural Health Monitoring (SHM) evaluates the integrity of a structure by
observing its dynamic responses by an array of sensors over time to determine
the current health state of the structure. The most important step of SHM is
system identification which in civil structures is the identification of modal
parameters of structures. Due to numerous limitations of input-output methods,
system identification of ambient vibration structures using output-only
identification techniques has become a key issue in structural health
monitoring and assessment of engineering structures. In this paper, four beams
with different boundary conditions and with arbitrary loading have been modeled
in finite element software, ANSYS, and the responses (Acceleration of nodes)
have been achieved. By using these data and the codes written in MATLAB
software, the modal parameters (natural frequencies, mode shapes) of the beams
are identified with FDD (frequency Domain Decomposition) and PP (Peak Picking)
methods and then justified with the results of input-output method which was
determined by frequency relation function (FRF). The results indicate a good
agreement between the three methods for determining the dynamic characteristics
of beams.Comment: Conference paper. arXiv admin note: substantial text overlap with
arXiv:2010.0749
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